Distribution network reliability enhancement through reliability based methodology

Full text

(1)COPYRIGHT AND CITATION CONSIDERATIONS FOR THIS THESIS/ DISSERTATION. o Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. o NonCommercial — You may not use the material for commercial purposes.. o ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.. How to cite this thesis Surname, Initial(s). (2012) Title of the thesis or dissertation. PhD. (Chemistry)/ M.Sc. (Physics)/ M.A. (Philosophy)/M.Com. (Finance) etc. [Unpublished]: University of Johannesburg. Retrieved from: https://ujcontent.uj.ac.za/vital/access/manager/Index?site_name=Research%20Output (Accessed: Date)..

(2) Distribution network reliability enhancement through reliability based methodology. By: Thando R Khumalo (Montso) 920311149. A Minor dissertation in fulfillment of the requirement for the degree MASTER in ENGINEERING MANAGEMENT In the FACULTY OF ENGINEERING AND BUILT ENVIROMENT – SCHOOL OF EGNINEERING MANAGEMENT Of the. UNIVERSITY OF JOHANNESBURG Supervisor: J.H.C Pretorius November 2016.

(3) Distribution network reliability enhancement through reliability based methodology. DECLARATION. I, Thando Roselette (Khumalo) Montso declare that the work presented in this research report, apart from the recognised assistance from my supervisor is solely my own and that it has not been submitted to another academic institution either by myself or another in obtaining a research qualification. I understand that unethical academic behaviour such as plagiarism is a serious offence to the University of Johannesburg which is dealt with by disciplinary action , thus all information obtained from external sources have been referenced to the best of my abilities and knowledge.. …………………………………………………. T.R Khumalo (Montso). Date ……………………………….. II.

(4) Distribution network reliability enhancement through reliability based methodology. ACKNOWLEDGEMENT. Much thanks and gratitude is given to firstly my God and creator, this dissertation wouldn’t be possible without the strength and spirit of endurance against all odds provided by him. I thank my husband Mr Montso & family, their prayers, support and encouragement to go on with the dissertation goes beyond words. They were there to help take care of my daughter when I was busy conducting the research and attending classes. I thank my Eskom colleagues who played a critical role in my research. Special thanks to Eskom reliability workgroup, Eskom information centre and especially my manager Mrs Cecilia Ntlhe who helped with giving critical info during the research. I thank all the respondents who gave valuable information and took their precious time in answering the questionnaire. I thank my supervisor JHC Pretorius, who gave guidance, constructive criticism and assistance in ensuring that I include relevant information in the dissertation.. T.R Khumalo (Montso). III.

(5) Distribution network reliability enhancement through reliability based methodology. ABSTRACT. Looking at the economic and technological growth of South Africa 50 years back until now, it is evident that electricity is very essential. The need of a reliable power distribution system has grown tremendously in this decade. The majority of the households and businesses rely on the functions of electric appliances and equipment to assist with daily tasks such as cooking, bathing, etc. The objective and function of Eskom is to ensure that electricity is delivered to every household and business in the country; hence, due to the rapid social development in areas such as Soweto, the distribution network operates under the pressure of being reliable against the odds of the network. This dissertation describes a methodology for reliability enhancement of distribution network system by calculating the reliability indices such as SIADI, SAIFI and RSLI in order to determine the improvements that can be done to the distribution network using the reliability based methodology. These indices indicate the performance of the system relative to its reliability namely the frequency of failures; the number of failures and the average rate of failures in the distribution system (includes feeders, reclosers, transformer, fuses, etc.). The problem of distribution system failure in Jabulani, Soweto has been decomposed in two stages. The first stage determines the optimum failure rates and the second stage optimizes repair times satisfying constraints. Identifying potential for power failure cost reduction through extended parts life of the system, reduced maintenance labour cost, and other parts of the network-related improvement techniques are essential in reducing the power constraints. The implementation of reliability based method in planning and design of capital changes in network layout is done to ensure full maintainability of equipment and utilities. Customer and energy based reliability indices are important to evaluate predictive performance of distribution network system. A case study of demand energy in Jabulani, Soweto has been presented to evaluate optimum failure rate and repair time for each section so as to achieve desired reliability goals in terms of the mentioned indices. Applying this reliability method helps in monitoring the distribution network feeders and consequently, improving its reliability.. T.R Khumalo (Montso). IV.

(6) Distribution network reliability enhancement through reliability based methodology. TABLE OF CONTENTS DECLARATION ......................................................................................................................................... II ACKNOWLEDGEMENT ............................................................................................................................ III ABSTRACT............................................................................................................................................... IV LIST OF TABLES ..................................................................................................................................... VIII TABLE OF FIGURES ............................................................................................................................... VIII ACRONYMS ............................................................................................................................................. X Chapter 1: Introduction and Context ...................................................................................................... 1 1.1. Introduction ............................................................................................................................ 1. 1.2. Background to the problem .................................................................................................... 2. 1.3. Problem statement ................................................................................................................. 7. 1.4. Aim and objective of the study ............................................................................................... 8. 1.4.1. Primary objective ............................................................................................................ 8. 1.4.2. Secondary objectives ...................................................................................................... 8. 1.5. Research questions ................................................................................................................. 9. 1.6. Significance of the study ......................................................................................................... 9. 1.7 Format of the study .................................................................................................................... 11 Chapter 2: Literature Review ................................................................................................................ 13 2.1 Introduction ................................................................................................................................ 13 2.2 Reliability management definition of terms and concepts......................................................... 14 2.2.1 Reliability risk management................................................................................................. 14 2.2.2 Reliability management general considerations ................................................................. 15 2.3 Eskom in terms of reliability ....................................................................................................... 16 2.3.1 Distribution Network System: Overview ............................................................................. 16. T.R Khumalo (Montso). V.

(7) Distribution network reliability enhancement through reliability based methodology. 2.4 Electricity distribution best practises and lessons from various international utilities. ............. 19 2.4.1 Power distribution reliability challenges: Lesson from Rwanda .......................................... 19 2.4.2 Power distribution reliability challenges: Lessons from independent regulation in Indian electricity....................................................................................................................................... 22 2.4.3 Power distribution reliability challenges: Rethinking the regulation of European electricity DSOs. ............................................................................................................................................. 24 2.5 Conclusion ................................................................................................................................... 26 Chapter 3: Research Methodology ....................................................................................................... 27 3.1 Introduction ................................................................................................................................ 27 3.2 Qualitative reliability research strategy ...................................................................................... 28 3.3 Research statement .................................................................................................................... 28 3.4 Reliability predictions methods .................................................................................................. 29 3.5 Analysis of research outcomes ................................................................................................... 30 3.6 Reliability research risk management ......................................................................................... 30 3.7 Reliability research modelling ..................................................................................................... 31 3.8 Research assumptions applied.................................................................................................... 31 3.9 Research validity and reliability .................................................................................................. 33 3.9.1 Cronbach’s Alpha as a reliability measure in the case study used as a pilot study ............. 33 3.9.2 Validity ................................................................................................................................. 34 3.9.3 Reliability.............................................................................................................................. 34 3.10 Limitation of the study .............................................................................................................. 35 3.11 Elimination of bias..................................................................................................................... 35 3.12 Ethical consideration................................................................................................................. 36 3.12.1 Privacy of possible and actual participants ........................................................................ 36. T.R Khumalo (Montso). VI.

(8) Distribution network reliability enhancement through reliability based methodology. 3.12.2 Maintenance of the confidentiality of data provided........................................................ 36 3.13 Conclusion ................................................................................................................................. 36 Chapter 4: Research Findings................................................................................................................ 38 4.1 Introduction ................................................................................................................................ 38 4.2 Analytical techniques used ......................................................................................................... 38 4.2.1 Determination of performance levels for an electricity distribution network .................... 40 4.2.2 Benchmarking performance levels in the context of distribution networks. ...................... 42 4.3 Case study research findings and results .................................................................................... 44 4.4 Employee survey results ............................................................................................................. 54 4.5 Response to the questionnaire. .................................................................................................. 55 4.5.1 Response graphs and discussion .......................................................................................... 56 4.6 Discussion of the reliability analysis used ................................................................................... 62 4.7 Improvement of distribution network reliability ........................................................................ 70 4.8 Conclusion ................................................................................................................................... 71 Chapter 5: Conclusion and Recommendations ..................................................................................... 72 5.1 Overview of the research ............................................................................................................ 72 5.2 Challenges encountered with the research ................................................................................ 72 5.3 General Conclusion ..................................................................................................................... 73 5.4 Recommendations ...................................................................................................................... 74 5.5 Future investigation .................................................................................................................... 74 References ............................................................................................................................................ 76 Appendix ............................................................................................................................................... 80. T.R Khumalo (Montso). VII.

(9) Distribution network reliability enhancement through reliability based methodology. LIST OF TABLES Table 1 : Legal and operational structure of the Group ......................................................................... 3 Table 2: The new organisation structure is indicated below ................................................................ 10 Table 3: Total energy losses experience by Electrogaz (Rwanda Utility) between 2004 and July 2009. (Source (Mwaura*, 2012)) .................................................................................................................... 21 Table 4 : Base case example for network reliability evaluation ........................................................... 32 Table 5: Network reliability optimisation strategies............................................................................. 42 Table 6: Worst events in the supply area. ........................................................................................... 50 Table 7: Soweto main substation's base load forecast. ........................................................................ 52 Table 8: Soweto main substation's future load forecast. ..................................................................... 53 Table 9: Load forecast for the new Jabulani 132/11kV Substation ...................................................... 54. TABLE OF FIGURES Figure 1: Eskom Distribution nation-wide network. ............................................................................... 4 Figure 2: The electricity value chain power delivery diagram ................................................................ 5 Figure 3 : Format of the study .............................................................................................................. 11 Figure 4 : Electricity purchase, sales and percent loss for Umeme between 2005 and 2010. ............. 21 Figure 5 : Adopted from Saunders et al. (2009:371) research validity ................................................. 33 Figure 6: Adopted from Saunders et al. (2009:371) research validity .................................................. 33 Figure 7: Reliability modelling decision work flow ............................................................................... 39 Figure 8: Geographical layout of Jabulani in Soweto ............................................................................ 45 Figure 9: Current sub-transmission network that feeds the distribution network for Soweto............ 46 Figure 10: Future network indicating the proposed Jabulani 132/11kV substation ............................ 47 Figure 11: SAIDI for the Zola CNC ......................................................................................................... 48 Figure 12: SAIFI for the ZOLA CNC ........................................................................................................ 49 Figure 13: RSLI for Zola CNC .................................................................................................................. 49 Figure 14: Power interruptions root cause for the Zola CNC................................................................ 51 Figure 15: Respondents Distribution .................................................................................................... 55. T.R Khumalo (Montso). VIII.

(10) Distribution network reliability enhancement through reliability based methodology. Figure 16: Occupancy of participants ................................................................................................... 56 Figure 17: Response on being part of the Reliability planning/maintenance team. ............................ 56 Figure 18: Respondents answers on being involved in distribution reliability outputs. ...................... 57 Figure 19: Respondents answers on power interruptions in Soweto.................................................. 58 Figure 20: Respondents experience of power outages in the past 3 months. ..................................... 58 Figure 21: Respondents knowledge of SAIFI. ........................................................................................ 59 Figure 22: Answer on the effectiveness of Eskom Reliability standard ................................................ 60 Figure 23: Response on the improvement of the Soweto distribution network. ................................. 60 Figure 24: respondent rating on the Soweto distribution Network ..................................................... 61 Figure 25: Response on the overall Johannesburg network. ................................................................ 62 Figure 26: Process to restore supply after a fault and key operational parameters ......................... 63 Figure 27: Process of sectionalising to limit fault finding distance (no substation RTU)................... 64 Figure 28: Sectionalising benefit of adding a substation RTU and a single FPI in improving the network reliability ................................................................................................................................. 65 Figure 29: Eskom SAIDI compared to United States (US), European Union (EU) and South America (SA)]....................................................................................................................................................... 67 Figure 30: Eskom SAIFI compared to United States (US), European Union (EU) and South America (SA)]....................................................................................................................................................... 67 Figure 31: CUOE curve diagram ............................................................................................................ 69 Figure 32: Focus on Reliability analysis in optimising the network (Source-Eskom). ........................... 70 Figure 33: Diepsloot’s illegal connections on the distribution network. .............................................. 75. T.R Khumalo (Montso). IX.

(11) Distribution network reliability enhancement through reliability based methodology. ACRONYMS. MV - Medium Voltage kV - Kilo Volt Km - kilometre MW - Mega Watt O/C - Over-current E/F - Earth Fault SE/F - Sensitive earth Fault RTU - Remote terminal unit ARC - Automatic reclosing cycle FPI -Fault Path indicator EPBS - Electricity Payment billing system GWh - Giga Watt per hour Hz-herdz COUE - Cost of Unserved Energy CNC -Customer Network Centre VT - Voltage transformer. T.R Khumalo (Montso). X.

(12) Chapter 1: Introduction and Context. 1.1 Introduction. Electricity is an essential product in South Africa. Considering the rate at which the country is growing, it has rather become more essential than before as many households depends on it to carry out their day to day tasks. Reliability has always been a concern in the energy sector, but concerns are escalating as energy demand increases and the political stability of many energy supply regions becomes more questionable (McCarthy, et al., 2007).The provision of reliable, secure and affordable energy services are central to addressing many of today’s global development challenges, including poverty, inequality, climate change, food, security, health and education (Brian Ó Gallachóir, 2012). They are also required for wealth creation and economic development.The South African bill of rights indicates that every citizen in the country has the right to electricity. In the White Paper on the Energy Policy of the Republic of South Africa (December 1998) from the Department of Minerals and Energy, the following definition is provided regarding Universal Access: “Government recognises that household access to adequate energy services for cooking, heating, lighting and communication is a basic need. Whilst these needs can be met by various fuel-appliance combinations, government recognises that without access to electricity, a clean, convenient and desirable fuel, human development potential is ultimately constrained. Government commits itself to implementing reasonable legislative and other measures, within its available resources, to progressively realise universal household access to electricity. Access to electricity is taken to include grid supplies, Solar Home Systems, generators, hybrid systems, battery systems or any other supply solution which provides an appropriate and affordable electricity supply. The decision of which technology to utilise, will be based on life cycle cost analysis and the number of connections made in terms of the budget allocation.”.

(13) Distribution network reliability enhancement through reliability based methodology. Currently Eskom has more than 8,000 individual Medium Voltage (MV) feeders (i.e. 1 kV – 33 kV) supplying more than 4.5 million customers, most of which were designed on a least-capital-cost basis with limited redundancy and back-feed capability. Focused initiatives are underway to improve the performance of the MV network in order to improve Eskom Distribution’s overall network reliability and technical performance (D GÜTSCHOW, 2013) .. 1.2 Background to the problem. Eskom has its head office in Johannesburg, with satellite operations located across South Africa (Limited, 2015). A Key function of Eskom is to buy and sell electricity to the countries of the Southern African Development Community (SADC). The future involvement in African markets outside South Africa (that is the SADC countries connected to the South African grid and the rest of Africa) is limited to those projects that have a direct impact on ensuring security of supply for South Africa (Eskom). It maintains a small office in London, primarily for quality control of the equipment being manufactured in Europe for the capacity expansion programme. The newly established Group Technology and Commercial division has as its core responsibility the oversight, monitoring and execution of the engineering and procurement (including primary energy) activities across Eskom, as well as oversight of the Eskom Enterprises group of companies. These are the new changes on the structure for Eskom. However, in the rush to implement reliability management, many ﬁrms are taking a much too simplisUc, ―one size fits all approach. Sourcing groups are quickly dividing goods into commodities, evaluating equipment quality, evaluating their current suppliers, consolidating purchases, and heavily leveraging their new purchasing power in order to improve the service and goods they provide their customers with. Firms can blindly seek the promises of strategic reliability management without understanding (H. P. BLOCH, Janaury 2008) the risks and the skills required. When high amounts of outsourcing and uncertain environments are involved, reliability management entails more complex tasks. It requires detailed analysis, long-term contingency planning, and a certain degree of introspection. Eskom Distribution is continuing researching the best practices to implement strategic reliability sourcing management since the T.R Khumalo (Montso). 2.

(14) Distribution network reliability enhancement through reliability based methodology. benefits have not being thoroughly realised. According to the purpose of maintaining a reliable power supply system, there change is to increase the organizations effectiveness or even to ensure its survival according to Harvey and Brown (2006: 159). Table 1 : Legal and operational structure of the Group. Source: Eskom Divisional Report (2012). The economic growth of South Africa heavily relies on the power delivery system. Figure 1 below indicates the national power distribution grid. Focused initiatives are underway to improve the performance of the Medium Voltage network in order to improve Eskom Distribution’s overall network reliability and technical performance (D GÜTSCHOW, 2013).. T.R Khumalo (Montso). 3.

(15) Distribution network reliability enhancement through reliability based methodology. Figure 1: Eskom Distribution nation-wide network. Source: (ESKOM GIS system Smallworld - TIPS). Eskom Distribution – Gauteng province economic activity in 2015 was comprised of the following: Industrial (1.7%), Mining (1.5%), Commercial (10%), Residential (9.8%), Agricultural (1.9%) & Redistributors (75.1%). The number of customers served just around the Nigel, Vaal Triangle, Westrand and Johannesburg are approximately 682 323 fed by 433 substations (Eskom, 2010-2019).. T.R Khumalo (Montso). 4.

(16) Distribution network reliability enhancement through reliability based methodology. Figure 2: The electricity value chain power delivery diagram Source: Eskom intranet (June 2015) Reliability management principles are not fully implemented at all Eskom Groups such as Group Commercial hence the benefits are not fully realised. Reliability management is still viewed by many organisations, particularly in developing countries, as a maintenance function and this result in missed opportunities for huge savings, which ultimately impact on the bottom lines of the organisation (Brian Ó Gallachóir, 2012) . Smart companies tap the power of their supply base not. T.R Khumalo (Montso). 5.

(17) Distribution network reliability enhancement through reliability based methodology. only for best-in-practise technological innovation but also for supply value chain improvements that can dramatically improve the performance of the national Grid. The problem at Eskom Distribution is maintaining a reliable electricity delivery network system at a reasonable cost (Cameron, et al., 2012). Most of the functions at Eskom Distribution still exclude cost effective reliability management in their early planning (functions such as procurement) and this further limits strategic sourcing opportunity in leveraging the overall saving for Eskom. The State Owned Company (Eskom Holdings SOC) which is known as Eskom plays a major role in the economy of South Africa and has been a monopoly in the electricity industry for approximately 100 years. The biggest challenge facing Eskom is the imbalance of supply and demand of electricity. As the current government is trying to electrify many of the households, previously excluded during the apartheid era, the country is now faced with electricity load shedding. Eskom is therefore building more power stations to balance the demand through its expansion build programme, but this process has its disadvantage as more people cannot afford electricity costs (Eskom, 2012-2015). The problems analysed for Eskom therefore has to use most its current reserves and to borrow money off shore to build additional power stations and to also maintain a positive financial statements. Increasing tariffs for electricity has its negative effect as the unemployment rates is high, and this is coupled with fuel increases. This all factors increase in the inflation for the entire country. Reliability management as one dimension can contribute to the bottom line of Eskom. The impact of reliability management has a positive outcome for not only Eskom profit, but also for the South African economy and the society at large. This research hopes to find solutions to current power reliability problems in Eskom and to provide to Eskom management, particularly at Eskom Distribution, solutions and develop preventative measures to the power delivery problems caused by an unreliable network in the country especially in political sensitive areas such as the biggest township in the country -SOWETO as looked after by Eskom.. T.R Khumalo (Montso). 6.

(18) Distribution network reliability enhancement through reliability based methodology. 1.3 Problem statement. Throughout the lifecycle of the network, zero interruptions and faults are ideal, but different factors impact the performance of the network. The causes are mainly due to design and topology of the network, planned operation and maintenance sessions and but not limited to physical infrastructure failures (Chauke, 2013) .The focus is on the factors that contribute to power outages such as unplanned faults and failures that occur on the physical structure of the network of which the typical causes are: •Incorrect design application •Poor construction •Equipment overloading •Poor condition due to inadequate maintenance / refurbishment •Environmental factors (lightning, vegetation, pollution). All of which have an impact on the undesired load shedding situation. An efficient and reliable model at the planning and design and operational stage of the network is necessary in monitoring this situation. This research also explores the causes of ineffective and unreliable power distribution by Eskom to the public in Jabulani, Soweto. Global recession during 2008 and the resulted negative reporting of financial statement have compelled Eskom to change its strategy for the generation and distribution of electricity. The new build programme project at Eskom, in which new power station are being build has resulted in the organisation to request guarantees from the government in borrowing money to cater for the escalated cost in building the power stations (Eskom, 2012-2015). Since the entire build programmes aims to bring more power capacity in the country, the purpose is to examine the causes, particularly network distribution reliability failures, so that recommendation may be made to Eskom management to ensure that the organisation can survive in terms of. T.R Khumalo (Montso). 7.

(19) Distribution network reliability enhancement through reliability based methodology. financial difficulties by optimising the distribution network with long term planning, and by doing so, also contributing to the government objectives.. 1.4 Aim and objective of the study The aim of this research is to determine factors that will improve the reliability management of Eskom Distribution regarding power delivery. The research objectives for this study are divided into primary and secondary objectives.. 1.4.1 Primary objective The primary objective of this study is to determine causes that have direct effect on the distribution power delivery network system. Benchmark the distribution network against the distribution network of other utilities internationally.. 1.4.2 Secondary objectives The secondary objectives of the research study are to: 1. Investigate how effective the distribution network reliability initiatives are as applied in Eskom Distribution. 2. Investigate how effective reliability management principle increases the power supply capacity of the distribution network. 3. Investigate the factors affecting the Eskom Distribution in carrying out its objectives. 4. Examine how SA government objectives affect Eskom network reliability goals. 5. Conduct a case study that will realise the result of implementing reliability management (Reliability based planning methodology). in the distribution (Soweto) grid to minimise power. failures.. T.R Khumalo (Montso). 8.

(20) Distribution network reliability enhancement through reliability based methodology. 1.5 Research questions The following are research questions: o. How efficient is Eskom Distribution reliability management system?. o. What reliability management standards are being used in the utility?. o. How is reliability management of the utility affecting its overall function?. o. What factors contribute to power system failures?. o. How are international utilities succeeding in power distribution reliability management?. o. What must be done to improve the elimination of power failures?. 1.6 Significance of the study. Although much theory has been written on the impact of how reliability management has on any organisation’s bottom lines, the question that remains is the implementation of this theory into practice. Every organisation, whether it is for selling goods or services, must implement reliability management in their activities in completing its transactions successfully. During the global recession of 2008, Eskom found itself in financial difficulties in its build programme to raise money. Build programme is the terminology used in Eskom in building more power stations to increase its megawatts. Today there are more uses of electricity that put pressure on Eskom electricity grid to meet the rising demands. During winter times, more electricity is used which results at times in load shedding. The importance of this study within Eskom is to show the impact and role that reliability management can play in saving money for the organisation, which can have a significance for the South African economy and thus contributing to some of the objectives that the current government. T.R Khumalo (Montso). 9.

(21) Distribution network reliability enhancement through reliability based methodology. is facing, namely halving poverty in 2018 and beyond (office, 2010-2030), also contribution to the promotion of black economic empowerment (BEE) etcetera. The high level of Eskom Organisational structure from February 2012 is listed below. The complete organisational structure is indicated in table 2. Table 2: The new organisation structure is indicated below. Source: Eskom Divisional Report (2013) Eskom has a number of subsidiaries: The Eskom Enterprises group provides lifecycle support and plant maintenance, network protection as well as support for the capacity expansion programme for all Eskom divisions (Eskom, 2012-2015). Eskom Enterprises operates primarily in South Africa; it has two subsidiaries that have an interest in electricity operations and maintenance concessions in Mali, Senegal and Mauritania as well as in Uganda. Eskom Finance Company grants home loans to Eskom employees. Escap, Eskom’s wholly owned captive insurance company, manages and insures Eskom’s business risk. The Eskom Development Foundation NPC is a wholly owned non-profit company that manages Eskom’s corporate social investment (Eskom).. T.R Khumalo (Montso). 10.

(22) Distribution network reliability enhancement through reliability based methodology. 1.7 Format of the study This. research. study. is. divided. into. five. Chapters. as. illustrated. in. Figure. 3.. Figure 3 : Format of the study 1.8.1 Chapter 1: Introduction and Context This chapter presents the problem statement of the research study, background to the problem, aim of the study, the context in which this study would be done, the research objectives, and the reason for this study. It will also define and explain the importance of the research.. T.R Khumalo (Montso). 11.

(23) Distribution network reliability enhancement through reliability based methodology. 1.8.2 Chapter 2: Literature Review This chapter reviews the literature relevant to this study. The discussions are aligned to both the research questions and research objectives of the study. The material reviewed indicates the worst and best practices that Eskom is benchmarked against. 1.8.3 Chapter 3: Research Methodology In this chapter, the research design and methodology will be elaborated upon. Included in the discussions are: introduction, research methodology, sampling strategy, the questionnaire construction, data collection, validity and reliability, limitations of the study, ethical considerations and chapter summary. 1.8.4 Chapter 4: Statement of Results and Discussion This chapter makes sense of the data through discussion. This involves stating what the theory says and outlines the author’s findings from the case study presented and the integration of the results of the questionnaire survey. The findings are presented and discussed under five sections aligned to both the research questions and objectives. 1.8.5 Chapter 5: Conclusions and Recommendations Conclusions and recommendations for the study are discussed in this chapter. Key elements raised will be revisited and recommendations will be made not only to mitigate the research problem, but also provide answers to the research questions and the associated investigative questions and case study results. These sections will include: findings from the study and findings from the primary research. This chapter presents the information pertaining to the context of the research. It provides the reasons for the research study with an overview of what the author has concluded in the research topic concerned and highlights the conclusion obtained from the study and recommendations from the research.. T.R Khumalo (Montso). 12.

(24) Distribution network reliability enhancement through reliability based methodology. Chapter 2: Literature Review. 2.1 Introduction. Reliability is like safety, it is much favored, yet the sustainability of it proves to be a challenge and can’t be overlooked. It’s an important factor when planning, designing and operating a system. People have always expected trains to be on time, electric power not to fail, telephones and communications lines to be reliable at any instant of time for an effective conversation, and so on (H. P. BLOCH, Janaury 2008) . A reliable electricity delivery system in South Africa has become more important since the stability of the economy relies heavily on it. Utilities around the world have been taking a fresh, hard look at managing reliability. Since risk management directly affects reliability management, in the process, utilities are redefining the role of reliability management in achieving objectives, and ultimately, increasing shareholder value. The main goal is not to totally eliminate risk, but rather to be proactive in assessing and managing risk for their advantage including the customers concerned (H. P. BLOCH, Janaury 2008). Reliability has over the past few years emerged as a widespread practice in utility organisations and has been increasingly included in regulatory, corporate governance and organisational management blueprints (DHILLON, OCTOBER 1986). However a question is always asked as to why are utilities/organisations struggling to implement, embed and sustain a pragmatic reliability management system solution that is robust, adds value and creates a balance between cost and reward, if risk management is a well-established philosophy and methodology? What measures need to be considered and implemented in order to optimise a reliable power delivery system? This study focuses on the evaluation of Eskom’s Reliability Management in one of its divisions (Distribution) and its impact or contribution to the power delivery management system as guided by the above-mentioned arguments. The discussions in this chapter are structured along the issues raised in both the research questions and research objectives. The literature review outlines the T.R Khumalo (Montso). 13.

(25) Distribution network reliability enhancement through reliability based methodology. definitions and explanations of key reliability management terms and concepts whilst highlighting the relevance of risk management to utility organisations and its relationship to strategic objectives. In addition, this chapter discusses the evolution, trends, principles, frameworks and best practices of international utilities that are widely applied relative to Eskom’s reliability management practices.. 2.2 Reliability management definition of terms and concepts. Reliability management has its roots in the military and space technology which keeps on evolving and improving (Utley). It started with few fields such as transportation and medical equipment, where people’s lives are involved and endangered by unreliable equipment. Its influence has been increasing into many other applications, e. g. nuclear and conventional power generation and transmission systems, communication systems, medical equipment and chemical systems (H. P. BLOCH, Janaury 2008). The assessment of reliability is no longer restricted to military equipment but also, the commercial world. The impact of reliability is becoming greater and greater (H. P. BLOCH, Janaury 2008). The world’s economy changes over time with a high speed and the industry has to keep up to survive. The power distribution system is also part of the applications that are influenced by reliability. 2.2.1 Reliability risk management Reliability engineering is the application of engineering knowledge to risk management. By increasing the probability that the network will operate or perform when needed by defining strategies to prevent failures, system operators must detect the onset of failures in their earliest stages, and minimize all risks associated with the overall network (DHILLON, OCTOBER 1986) (Utley). Identifying potential for cost reduction through extended parts life reduced labour cost, and other parts or equipment-related improvement techniques. The Participation in review phases of design of capital changes in network layout is done to ensure full maintainability of equipment and utilities (Cameron, et al., 2012).. T.R Khumalo (Montso). 14.

(26) Distribution network reliability enhancement through reliability based methodology. The Initiation of corrective action using the study of corrosion, fatigue, wear, and erosion rates throughout the life cycle of the network reduces the reoccurrence of failures (Brunekreeft, 2015). Also Alternate solutions to reduce the high costs associated with certain units of equipment. The application of reliability modelling addresses these reliability risks. 2.2.2 Reliability management general considerations Reliability management considers a number of factors in an electricity delivery system .Factor such as increasing system complexity and size, economics, and competitiveness in the market. South African distribution increases in the number of connections everyday as new residential and commercial dwellings develop daily. Under present environments, neither can overdesigns be permissible nor unreliability be tolerated, as in the case of load shedding. In this respect, management plays an important role by guiding input to the specified reliability and the ways and means to achieve it (Brian Ó Gallachóir, 2012) (Brown, 2008). In order to have an effective reliability program that will ensure optimisation of a distribution network system, there are various factors in which the responsibilities of management are embedded in, namely: 1) The establishment a program to access in real time, with respect to reliability, the current performance of the utility operations performance; 2) The establishment of certain reliability objectives or goal, in this case, ‘Keeping the lights on’; 3) The establishment of an effective program to fulfil set reliability goals and eradicating current deficiencies. An absolutely effective program should be able to pay in return many times its establishing cost; the public’s corporation plays a role in this regard; 4) Providing necessary program related authority, funds, manpower (qualifies personnel), and time schedule; 5) Monitoring the program -on a regular basis (National Grid performance power alert system and modifying associated- policies, procedures, organization and 'so on, to the most desirable level (Brown, 2008).. T.R Khumalo (Montso). 15.

(27) Distribution network reliability enhancement through reliability based methodology. Facts such as the following are a guiding force for the general management to have an effective power delivery reliability program. Changes in maintenance, storage, testing and usage in field of the engineering product tend to lower the reliability of the design. Planned programs are needed for application in design, manufacturing, testing and field phases of the engineering product to control reliability (Arends, et al., 2014). It is during the early phases of the design (planning included) and evaluation testing programs when high levels of reliability can be achieved most economically. Power distribution performance indicators assist in incorporating reliability in a network.. 2.3 Eskom in terms of reliability. Eskom Distribution’s power network has experienced rapid expansion since the early 1990’s in keeping with the government’s policy of extending electricity as a basic service to millions of previously disadvantaged citizens. The power delivery network operates under pressure .Focused initiatives are underway to improve the performance of the MV(medium voltage) network in order to improve Eskom Distribution’s overall network reliability and technical performance (Newbery, 2002). Since the inception of the electrification programme (or universal access) in 1991 Eskom has connected 4.05 million new households to the electricity grid (D GÜTSCHOW, 2013). The current and past approach to connecting electrification customers did not explicitly consider the impact that such connections (based on current design for such connections) would have on both the national system’s performance and the economic cost implications thereof (Cameron, et al., 2012). Consequently, electrical network infrastructure provision in South Africa has traditionally been based on a least-cost approach for the last 20-plus years.. 2.3.1 Distribution Network System: Overview The Distribution network is made of a number of equipment, namely – power generator, power transformers, overhead line, underground cables, etc. The combination of the equipment allows for power delivery to the customers (Eskom). In order to ensure visible performance of the. T.R Khumalo (Montso). 16.

(28) Distribution network reliability enhancement through reliability based methodology. aforementioned equipment, there are electronic devices that are installed at various places of the network being the following: Automatic reclosers. Automatic reclosers are hydraulically or electrically operated devices. that can sense over-current (O/C), earth-fault (E/F) or sensitive earthfault (SE/F) conditions. Under these conditions the recloser will, subject to pre-determined settings, trip and after a time delay re-close automatically. If the fault is not cleared the recloser will go through a fixed sequence of trip and re-close cycles after which it will lock out. When the recloser is in the lock-out mode the faulted section will be isolated from the supply and human intervention is required to close the recloser. Integrated automatic reclosers have integrated remote terminal units (RTUs) that enable remote control and monitoring. Automatic. sectionalizing Sectionalisers are hydraulically or electronically operated devices that. devices. are used in conjunction with an upstream recloser to isolate a fault. These devices do not have fault breaking capability and rely on the upstream recloser to detect and open for a downstream fault. The device isolates the faulted section before the recloser finishes a sequence of automatic reclosing cycles (ARCs) and locks out. Sectionalisers can be current operated, voltage operated or a combination of both.. Fuses. Expulsion fuses, installed in a fuse cut-out base, are used extensively in. Eskom. These fuses provide a relatively inexpensive yet effective method of clearing fault current. Fault path indicators. A fault path indicator (FPI) is a device that provides a visible and/or. remote indication that fault current passed through the location at which the FPI is installed. It is thus a very useful fault finding device,. T.R Khumalo (Montso). 17.

(29) Distribution network reliability enhancement through reliability based methodology. Remote terminal unit. A remote terminal unit (RTU) is an intelligent electronic device that. facilitates remote control and monitoring of electrical equipment by means of a communications network. Through the use of RTUs the control centre has remote visibility and control over substations and switchgear installed on feeders. Indoor switchgear. Indoor switchgear refers to metal-clad switchgear that can be of the. fixed pattern or withdrawable type. It excludes gas-insulated switchgear (GIS) as well outdoor switchgear used indoors. Outdoor switchgear. Outdoor switchgear refers to switchgear designed to be used outdoors. in combination with air insulated busbars. Gas insulated switchgear. Gas insulated switchgear refers to switchgear assemblies that contain. gas-insulated busbars. These components form part of the power delivery system .The system comprising generation, transmission and/or distribution, are subjected to many adverse events such as accidents, random component failures and weather conditions resulting in power interruptions (Qzobo, et al., 2012).The use of these devices is very crucial because faults, network interruptions and failure maybe caused by different reasons .The causes are mainly due to design and topology of the network, planned operation and maintenance sessions and but not limited to physical infrastructure failures. Major contributors on load planned, unplanned faults and failures that occur on the physical structure of the network of which the typical causes are: •Incorrect design application (feeders design without contingency) •Poor construction •Equipment overloading •Poor condition due to inadequate maintenance / refurbishment •Environmental factors (lightning, vegetation, pollution).. T.R Khumalo (Montso). 18.

(30) Distribution network reliability enhancement through reliability based methodology. 2.4 Electricity distribution best practises and lessons from various international utilities.. The reliability challenges that the South African National distribution grid is facing is not entirely new. Utilities internationally have been and some are still having challenges of providing a reliable power system. The international community is vastly growing. The climate is ever changing. Optimisation of the power distribution system internationally, at least cost to both the supplier and consumer is the solution. 2.4.1 Power distribution reliability challenges: Lesson from Rwanda Before 1947 electricity was supplied by a private entity called the East Africa Power and Lighting Company (EAPLC), which operated diesel generator stations in Kampala and Ninja. The company had a total installed capacity of 12.1MWand served about 3200 customers in the two towns. Later in that same year the government corporation, Uganda Electricity Board (UEB) was established by an Electricity Ordinance and started operations in June 1948 (Mwaura*, 2012). During the 1970’s to 1980’s the electricity infrastructure suffered neglect in terms of maintenance, then couldn’t perform optimally. A significant proportion of energy produced was lost due to power transmission and distribution system breakdown, and the inability of UEB to bill and collect money from electricity users. Uganda’s electricity generation potential of 5300 MW including hydro (2000 MW), biomasscogeneration (1650 MW), peat (800 MW), geothermal (450 MW), mini hydro (200 MW) and solar (200 MW), is poorly developed).There were some low investments. Reasons for low investment in the electricity sub-sector have been identified assets , perceived technical and financial risks by the private sector in Uganda .Although the total electricity demand was estimated at 580 MW by 2005, the country installed capacity is 464 MW with actual power generation ranging from 195 to255 MW. The situation is aggravated by unpredictable rainfall and is likely to suffer from climate change (Mwaura*, 2012).. T.R Khumalo (Montso). 19.

(31) Distribution network reliability enhancement through reliability based methodology. The situation worsened in Rwanda .The country experienced high non-technical energy losses estimated at 18 percent of the total generated power remained a major constraint for Uganda as it pursues transformation to a modern economy. Consensus has been reached among electricity stakeholders on the importance of prioritizing reduction of non-technical energy losses in the subsector. These non-technical losses refer to electrical energy lost through theft, which could be in form of illegal connections, fraud or non-payment of bills. The high energy loss had a disastrous impact on the power sub-sector, both on supply and demand side management. Illegal tapping of power from the distribution lines led to overloading of the power delivery system resulting in intermittent power disruptions (Mwaura*, 2012). Those who pay for power were exorbitantly charged to cover the costs of energy lost (due to illegal connections) as the utility companies pursue cost recovery strategies. Failure to implement energy loss reduction strategies has impacted negatively on government’s efforts to increase connectivity and increase supply to meet the expanding demand effectively and affordably. The Rwanda utility took relevant intervention to counter-act the effects of energy losses due to lack of reliability management in their power delivery system. Control and preventative failure maintenance was implemented to alleviate the risk of collapsing the power grid. The EPBS (Electricity Pre-Payment Billing System) information technology-based innovation that mostly utilizes a “smart card” was also implemented. This technology requires the customer to make advance payment before electricity can be used. If the available credit is exhausted then the supply of electricity is cut off by a relay. Illegal connections were significantly reduced and utility profits. T.R Khumalo (Montso). 20.

(32) Distribution network reliability enhancement through reliability based methodology. increased. The figure5 below indicates Rwanda’s utility increase in system reliability and profits.. Figure 4 : Electricity purchase, sales and percent loss for Umeme between 2005 and 2010. (Source (Mwaura*, 2012)). Table 3: Total energy losses experience by Electrogaz (Rwanda Utility) between 2004 and July 2009. (Source (Mwaura*, 2012)). The benefits of energy losses reduction in Uganda included reducing cost of thermal generation; reducing tariff; improving power planning and implementation; improving profitability to power T.R Khumalo (Montso). 21.

(33) Distribution network reliability enhancement through reliability based methodology. utility distributors, manufacturing sector and the entire economy; reducing load shedding; breaking the hindrances to wider and quality distribution (Mwaura*, 2012). These benefits as they harnessed strongly, they would lead to economic growth, environment protection and reduction of incidences of diseases associated with poor energy sources such as the use of paraffin and biomass; poverty reduction; stimulation of investments in the sub-sector; and withdrawal of government subsidy to shield private entities . Rwanda Electrogaz continues currently to implement these reliability management strategies in order to supply electricity reliably to its communities.. 2.4.2 Power distribution reliability challenges: Lessons from independent regulation in Indian electricity. The electricity reliability challenges that were present in the past two decades in India were influenced by the political and economic situation. Many developing countries introduce independent regulation of power distribution as part of a larger program of electricity reform and restructuring (Navroz K. Dubash, 2008). Dating back to 1989, the Indian national electricity state was operating under huge constraints due to power shortages and uneconomical operations (Navroz K. Dubash, 2008). There were four major regional grids, namely: eastern, northern, western and southern. These regions were managed by five regional electricity boards (REBs), which monitored the interstate (within the region) and interregional exchange of power .these board operated differently which contributed to unreliable power supply in the country. The primary power resources of which were mainly coal accounted for 62% of the total generation and was concentrated in relatively small areas which were in the southern and eastern regions. In order to get the energy resources to these two regions, coal was to be transported over long distances – in some cases in excess of 1000 km (Navroz K. Dubash, 2008). That incurred high cost of transportation which made generation of power expensive for many coal-based plants. Operations in the southern region were highly constrained by the required licences and releases of water for irrigation, which took preference for multi-purpose hydro projects. Projects to build new hdro power stations were delayed . T.R Khumalo (Montso). 22.

(34) Distribution network reliability enhancement through reliability based methodology. In 1995 India power contraints got worse because of the integrated operations of the 5 boards. The power boards needed to overcome serious hurdles which were hampering the development of the country. These hurdles were constraints that were categorised into the following: infrastructural constraints, operational constraints and institutional constraints. Infrastructural constraints: There was an overemphasis on goals such as regional self-sufficiency made at the cost of sacrificing the benefits of a total systems approach that would have benefited the country. There were weak connection links between and within regions of which limited interregional power transfers. It was estimated that construction of additional inter-regional links would have led to additional utilization of 6500-6700 GWh. There was lack of communication facilities amongst the power boards which resulted in a large number of grid collapses, long response and restoration time, and unscheduled power flow among states. There was lack of metering facilities for power exchanges, real-time monitoring and an efficient accounting system. The availability of funds for building transmission links and system control facilities, which was l estimated at Rs.500-600 million over the next8-10 years. The economic state of the country was challenged with this constraint. Operational constraints: There were technical Large-scale voltage fluctuations (320-430kV on a 400kV bus), frequency deviations (48.0-51.5Hz), and inadequate reactive power compensation at all voltage levels. The lack of grid, discipline in the system, in terms of penalties for overdrawing and underdrawing by SUs from the scheduled transfer and time-of-use pricing schemes. Institutional constraints:. T.R Khumalo (Montso). 23.

(35) Distribution network reliability enhancement through reliability based methodology. The Lack of commercial agreements between the SUs resulted in energy being traded under ad hoc arrangements which were rarely related to the marginal cost of generation and was without appropriate division of benefits between the importers and exporters. The unremunerated tariff structure in terms of providing electricity was at a highly subsidized rate to agricultural consumers of which results in poor financial performance of SEBs. Indian electricity regulators were established explicitly to de-politicize the sector, but little thought was given as to whether devolving legal power to regulatory technocrats was a sufficient way to overcome these power constraints faced by these Indian state (Navroz K. Dubash, 2008) . The political state of the country influenced how the energy regulator operated. The national grid was a promising option for improving upon the status of power shortages and uneconomic operations that existed in India. The Indian power crisis experience suggested that in a rapidly changing electricity sector, the separation between the political and economic content of regulatory decisions, as is often advocated, may not be feasible or indeed desirable. The national Grid standardised how the different state utilities operated .The building of a democratic legitimacy was necessary, which required a focus not only on robust legal procedures and adequate training of regulators and their staff, but also support for citizen engagement in regulatory processes that were insuring a reliable power system in the country. This was implemented and India continues to ensure that power is deliverer reliably.. 2.4.3 Power distribution reliability challenges: Rethinking the regulation of European electricity DSOs. European countries also faced power reliability challenges. The drive to renewable energy was influenced by the demand of power which was by far more than the available supply of power generated. The technological advances are reshaping how power systems operate in ensuring an optimised network at a distribution level.. T.R Khumalo (Montso). 24.

(36) Distribution network reliability enhancement through reliability based methodology. More mature technologies which are used such as the renewable generation, have decreased the related investment costs and optimised the distribution power network by operating reliably. The national support schemes have led to a significant market penetration of distributed generation (DG) in many EU countries. (Revuelta*, 31 January 2014) For instance, in Germany, “in some parts of that country, the DG output of the power distribution networks had already exceeded the local demand load, sometimes by multiple times” (Eurelectric, 2013) (p. 3).this resulted in power outages due to the system failure and longer response time in restoring system optimal operation.The storage of power was not available at all voltage levels. Research indicates that this is still the case in a number of European countries. This situation placed the DSO (Distribution system operators) in a state where they had to investigate how the regulation of European electricity DSOs should be adjusted so that there could be least friction between the utilities and the regulators. In order to overcome the power constraints in EU, the energy regulators indicated that the use of local resources will alleviate the problem faced by these countries. These local resources can provide a diversity of services with economic value, and may successfully compete with centralized generation in offering new tools for system control. A more active distribution system management could help to decrease the total cost of DSOs compared to the traditional “fit-and-forget approach” of merely connecting the new devices to the network to measure power usage .Firstly to create a level playing field for the market needed to be created at the entry of DER technologies, and secondly, the utilisation (directly or indirectly) of local resources could assist in managing the distribution system efficiently. The question is : What are the EU countries doing to overcome power constraints? The solution used is to keep regulation at a minimum level, and respect the principle of subsidiarity. Accordingly, there is also neither a need, nor a solid justification, for an EU-wide comprehensive harmonization of the regulation of DSOs. Recent innovations in metering and communication devices installed in the distribution grid enable active demand response and enhanced distribution automation, thereby facilitating and allowing for a wider deployment of distributed generation, local storage and electric vehicles.[10] The difference is that at the beginning of the liberalization process demand response was considered only interesting for large, typically industrial customers. Technological advances (for example, intelligent metering and control systems that can optimize individual consumption T.R Khumalo (Montso). 25.

(37) Distribution network reliability enhancement through reliability based methodology. patterns are used so that customer can be involved in monitoring their power consumption, thereby reducing risks and efforts related to reacting to price signals) which also make this concept interesting for the smaller-scale commercial and residential sectors. According to a positive cost benefit analysis, at least 80 percent of European households should be equipped with intelligent metering systems by 2020 (European Commission (EC), 2009). In addition, distributed storage might soon become viable at all voltage levels and in large amounts, of which is a critical component of “the grid of the future” (Revuelta*, 31 January 2014). Likewise, the use of electric vehicles charging from the grid, and possibly also injecting power back into it and delivering so-called vehicle-to-grid services, is also projected to grow, thus a reliable power distribution system would be achieved and maintained.. 2.5 Conclusion. Many countries have faced challenges that are similar to what the South African power utility is facing (Brian Ó Gallachóir, 2012). On one hand, the recent multi-day blackouts across much of India made it painfully clear that the ability to correctly predict (and react quickly to) power disaster scenarios is prized by risk, adverse shareholders, sympathy-infused publics, and politicians keenly attuned to the 24-h news cycle (Navroz K. Dubash, 2008). On the other hand, India’s blackouts also demonstrated that resources – financial, technical, and ecosystemic – are in perennially short supply, engendering a focus on the primacy of ephemeral successes at the expense of long-term sustainability, investment, and durability. The different best practises revived the distribution grid of the mentioned countries.. T.R Khumalo (Montso). 26.

(38) Distribution network reliability enhancement through reliability based methodology. Chapter 3: Research Methodology. 3.1 Introduction. This chapter discusses the research design and methodology used in the study .The objective is to integrate the literature that was reviewed in chapter2 with the problem statement that was discussed in the first chapter and the researched questions. The research was under taken within Eskom Network Planning proceedings to determine the impact they can have in addressing the question posed in chapter1, particularly on the impact that network planning has in ensuring that the network has minimal failure. The distribution system reliability is most important in measuring the service quality which can have an impact on the profit maximisation and network optimisation of the organisation. This research also checks whether Eskom has the complete reliability resources to use to its advantage and whether Eskom is effectively contributing to the objectives of SA in ensuring that electricity is available to the nation on a continuous basis. The main problem researched is restated along with the data collection, measuring tools and limitations to the study. According to Saunders, Lewis and Thornhill (2009:5) define a research as something that people undertake in order to find out things in a systematic way, thereby increasing their knowledge. Below is the different research approach design methods considered in this study. o. Explanatory research – It’s a research that focuses on studying a situation or a problem in order to explain the relationships between variables. and. o. Exploratory research – It’s a research that aims to seek new insights into phenomena, to ask questions, and to assess the phenomena in a new light. (Wellman, et al., 2005). It would be sensible to define business reliability management research as undertaking systematic research to find out things about business and management regarding network reliability. The researcher adopted an exploratory approach to the study by means of the descriptive case study research method with a questionnaire and simulations. T.R Khumalo (Montso). 27.

(39) Distribution network reliability enhancement through reliability based methodology. 3.2 Qualitative reliability research strategy. Eskom’s business environment is very dynamic so it’s constantly changing. This makes it necessary to implement new and diverse methodologies to provide an organization with reliability advantages. Firstly we need to understand what reliability means. Reliability is defined as the probability that an item or a system for example, production or utility asset and work processes, will continue to do what the user needs it to do without failure under specified conditions for a specified period of time. (DHILLON, OCTOBER 1986) Qualitative research strategy was adopted in this study since it involves the subject of an objective nature. Exploratory research had to be conducted as the subject is of a qualitative nature because of the limited volume of knowledge available on the subject considered (Partington, 2002). The advantages of the research strategy for this study are the following (according to online classroom, 2011): Allows researchers to test for validity of theories, assumptions, claims or generalization in reality; The nature of different situations are revealed, such as, systems, people, relationships, etc. Gain new insight , rhetorical perspective and problems about a certain subject or phenomenon The researchers can check the effectiveness of certain policies, practices and innovations of systems. Network performance data was collected and analysed to research the theories and assumptions applied in this study.. 3.3 Research statement. T.R Khumalo (Montso). 28.

(40) Distribution network reliability enhancement through reliability based methodology. The study seeks to ensure that there is a clear understanding of the causes of nation-wide power failure. The critical factors for electricity delivery system success within Eskom Distribution are considered in order to recommend ways in which these challenges can be addressed to ensure improvement in optimising the organisation’s power distribution network performance.. 3.4 Reliability predictions methods. The early reliability prediction can aid evaluation of produce ability, maintainability, whole-lifecosting, warranties and logistic support for optimising the distribution network. The most obvious reason for performing a reliability prediction research methodology is to determine whether a proposed network design will meet a numerical, or another equivalent statement of, reliability requirement that will improve the performance of the network (Cameron, et al., 2012). Reliability network predictions are used to assess alternatives and provide design direction in the early stages of network development and improvement (Cameron, et al., 2012). This could save time, money, other resources such as personnel & transport and it could improve the design .This method aids in the final network design stage where changes won’t be very expensive. An accurate prediction of the reliability of a new network, before it is developed, is obviously highly desirable. Optimistic (too high) or non-credible reliability predictions have led to unanticipated disasters; and pessimistic (too low) reliability predictions can lead to over planning of network by having a surplus of spare to maintain the network and, at its worst, lead to demise of systems due to high cost, or, if yet developed, being to over expensive (Rel). The objective of this mini dissertation is to determine factors that will improve the reliability management of Eskom Distribution regarding power delivery.. T.R Khumalo (Montso). 29.

(41) Distribution network reliability enhancement through reliability based methodology. 3.5 Analysis of research outcomes. Data analysis is the statistical design and tests applied to the obtained data to test the various hypotheses (Partington, 2002) (Naoum, 1998). Once data processing has been completed the analysis of this data should follow. The purpose of grouping data is to reduce the number of figures or scores presented in a distribution to enable the reader to grasp the main features of the data and to present the information more effectively (Wellman, et al., 2005).. 3.6 Reliability research risk management. Reliability engineering is the application of engineering knowledge to risk management. By increasing the probability that the network will operate or perform when needed by defining strategies to prevent failures, system operators must detect the onset of failures in their earliest stages, and minimize all risks associated with the overall network (H. P. BLOCH, Janaury 2008). Identifying potential for cost reduction through extended parts life reduced labour cost, and other parts or equipment-related improvement techniques. The Participation in review phases of design of capital changes in network layout is done to ensure full maintainability of equipment and utilities (Cameron, et al., 2012). The Initiation of corrective action using the study of corrosion, fatigue, wear, and erosion rates throughout the life cycle of the network reduces the reoccurrence of failures. Also Alternate solutions to reduce the high costs associated with certain units of equipment. Reliability modelling addresses these reliability risks.. T.R Khumalo (Montso). 30.

No results found