Smart Grid, Smart City Project

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Smart Grid, Smart City

Project

Monitoring and Measurement Report

Report III

Grid Applications

Substation Feeder Monitoring

01 January 2012 – 30 June 2012

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Smart Grid, Smart City Monitoring and Measurement Report III – Substation Feeder Monitoring 2 IMPORTANT NOTE:

In a number of attachments, Ausgrid has removed certain material that we do not consider

appropriate to release, such as personal information and commercially sensitive financial information. Ausgrid believes the removal of this information does not detract from the general value of the information or findings in the attachments.

This document has been approved for publication by Ausgrid and the consortium partners who contributed to it. The document has been prepared with all reasonable care and responsibility. Ausgrid believes these findings to be technically and factually accurate when applied to Ausgrid’s network as at the date of those findings.

However it should not be considered a recommendation and naturally, it would be prudent for anyone who wishes to rely on, or use the information in this report to independently verify its accuracy, completeness and suitability for use for their own purpose.

Consequently, Ausgrid makes no representation or warranty as to the accuracy, currency, reliability, completeness or suitability, of the information in this report. You acknowledge that Ausgrid (and its officers, employees, agents and consultants) to the full extent permitted by law, excludes all liability: (a) (including liability to any person by reason of negligence or negligent misstatement) for any statement, opinion, information or matter (expressed or implied) contained in, and for any omissions from, this document; and (b) arising out of your use of or reliance on this document and any

information contained in it.

Ausgrid owns copyright in (or otherwise has the rights necessary to publish) this document. You may only reproduce this document with the permission of Ausgrid.

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Smart Grid, Smart City Monitoring and Measurement Report III – Substation Feeder Monitoring 3

Attachment List

Area Title Category Type

SFM MMR3_GA_SFM_DGA Merewether.xlsx Raw Data Spreadsheet SFM MMR3_GA_SFM_Preliminary Report - DGA

for Merewether.pdf

Report Adobe

SFM MMR3_GA_SFM_DTR S02904.xlsx Raw Data Spreadsheet

SFM MMR3_GA_SFM_DTR S08502.xlsx Raw Data Spreadsheet

SFM MMR3_GA_SFM_Environmental HS39614 Temperature.xlsx

Raw Data Spreadsheet

SFM MMR3_GA_SFM_Environmental HP13102 Temperature & Humidity.xlsx

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1 Interoperability

1.1 Introduction

This suite of applications for SGSC looks at the condition of substation and feeder assets and the quality/characteristics of power.

Substation monitoring techniques look at oil condition on transformers and power characteristics. The transformer monitoring implementation is complete (on a single deployment – considered sufficient for the project) and is currently providing data which is contained in the data gathering section. Power characteristics monitoring from the PowerSense RTU implementation is providing data plus analysis results, which are included.

Feeder monitoring uses a range of techniques from distributed temperature, partial discharge, condition of oil and gas cables, weather and low voltages from smart meters. Progress is mixed through installation to operate, acquire and report results. The implementation of temperature sensors in the cable systems is currently being completed, allowing status reporting but no analysis and results in this progress update. The partial discharge analysis has been designed with

procurement and implementation complete. Data collection has just commenced and no meaningful data or results can yet be reported. Oil condition monitoring of cables is being implemented, but is still to be commissioned for data reporting. Some weather monitoring has been deployed on sites, with some installations just completed as an integrated portion of PowerSense data acquisition. Those sites where it is implemented had initial data reports, which are included. Business groups have an improved understanding on the potential for this information, allowing effective case study preparation.

Substations (IEC 61850 compliant) with feeder monitoring technology have had their designs finalised, apart from the LAN’s designs, which are still to be finalised. Two substations with 61850 compliant functionality installed, are in build progress; the first is Rathmines substation, due for completion in September 2012. The second substation at Broadmeadows is due for completion at the end of 2012. No data is available from these substations.

Wireless Communications. At the moment 3G communications supports non fibre connected smart grid points. Selection of a 4G equipment vendor and limited functionality testing has been completed. Negotiations on supply of equipment have been completed. Procurement, delivery and

implementation is pending, however connectivity needed by field devices is occurring with the existing Telco 3G network connections.

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1.2 Addressing the SFM Data Priorities

The Substation and Feeder Monitoring trial design and data collection to date have been addressing the Data Priorities of the SGSC program as described in the table below:

Project Data Priorities Addressed in SFM Trials Though Quantify and understand the

potential of reduced operating costs and improved energy efficiencies associated with substation and feeder monitoring

The SFM trials include monitoring and measurement of asset condition as well as grid power characteristics (voltages, current, and power factor) for specific assets including HV underground cables, zone and distribution transformers. The program also leverages Ausgrid’s much broader distribution monitoring rollout creating a data set across thousands of distribution transformers. By monitoring these characteristics the SFM program informs the potential for operating cost savings in areas including:

• Reduced manual inspection and measurements

• Reduced or avoided reactive and proactive maintenance activities

• Reduced or avoided equipment failure, repair, and/or replacement activities • Reduced costs of secondary equipment inspections, battery replacements

etc

• Reduced costs of some customer requested services such as voltage complaints

• Avoided outage costs / STPIS benefits

With respect to energy efficiency, the SFM initiatives inform overall network loss calculations, identification of imbalance conditions, and the impacts of load cycles on transformer and cable heat losses. Moreover, by monitoring distribution level power flows, the potential grid impacts of energy efficiency actions by customers can be more closely assessed. For example the impact of increased solar PV installations.

Understand, analyse and report how these technologies operate as part of an

integrated smart grid and contribute to enhanced network efficiencies

The operation of SFM technologies as part of an integrated smart grid is informed through integration with Ausgrid’s broader operational technology platform. Distribution substation transformer monitoring data is directed into the DM&C historian and visualization application, and SCADA collected data is also available on the common technology platform.

The contribution to network capital efficiency is informed by the SFM technologies in areas including:

• Potential network augmentation deferrals though:

o Monitoring actual peak loads and associated temperature effects o Better informed power factor correction

o Better informed demand management programs

• Potential re-rating of substations and feeders through monitoring of ‘limiting factor’ equipment such as fans, batteries etc

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1.3 Distributed Temperature Sensing

1.3.1 Introduction

Distributed Temperature Sensing (DTS) is a system that uses a laser emitted into a fibre optic cable to measure the temperature that the fibre experiences to a high resolution and accuracy.

DTS fibres may be integral to the cable design, attached to the outside of the cable, or in an adjacent conduit. For new sub-transmission cables, Ausgrid either runs a conduit alongside the cables, through which a fibre optic cable can be blown down the conduit using compressed air, or uses cables where one of the wires in the earth screen has been replaced with a fibre optic cable (the former has been preferred due to the relative ease of jointing).

Since January 2011, the SFM project team, along with representatives from various Ausgrid business groups, have been scoping and designing trials relating to DTS technology on the Ausgrid network. The project is now at the stage where installation is completed and commissioning work is

progressing at the Merewether STS. It is expected that experimentation relating to the capability of the monitoring systems and the relevance to the Ausgrid network will be undertaken from October 2012.

Preliminary results from the experiments will be available from November 2012.

For any cable that is DTS capable/ready, there is the potential for the application of the technology to perform:

• Reassessment of design criteria for static ratings

• Real time rating of cables allowing temporary increase of ratings over cables

• Life cycle asset management and targeted capital investment including deferral of capital works

• Identification of hotspots and identification of deviations from design criteria (e.g. Thermal resistivity changes such as vegetation and new heat sources such as roadways)

1.3.2 Activities

Over the last 18 months, the DTS project has progressed by:

• Engaging Ausgrid's, Transmission Mains, and Ratings & Supply groups to obtain requirements and identify current legacy systems on Ausgrid's network

• Gain an understanding of the supply market via a restricted tender to establish supplier capability in both the physical monitoring and real time ratings areas

• Conducting experiments at Merewether STS that aim to address and compare different fibre configurations, monitoring systems and rating systems (current activity)

• Integrating DTS into a centralised system of data management and control • Assessing the organisation's ability to deliver and manage / operate the system Existing systems

At the start of the SFM trial, two existing DTS systems were identified on the Ausgrid network: City South – Hitele and the Sensornet – Sentinel portable unit. However, both these units were non-functioning and unsupported by their suppliers. Remediation and re-calibration of the Sentinel device were performed and this unit will be re-introduced into the test bed at Merewether. The Hitele unit will not be repaired as there are no ongoing support options available for this device.

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Smart Grid, Smart City Monitoring and Measurement Report III – Substation Feeder Monitoring 8 It has been established that the first cables to support DTS were introduced to Ausgrid’s network in 2000 on the 33kV – Warringah feeder and 132kV – Bankstown to Greenacre (291/2) feeder around 2002.

A preliminary analysis of the numbers of feeders installed after this period, sourced from the GIS system, is estimated to be:

• 33kV – 210 Feeders • 132kV – 92 Feeders New systems

Two new systems have been purchased as incremental offerings related to the Ausgrid cable works program. The first, a LIOS unit, will be installed to monitor the feeders at the Kogarah Zone

Substation. The second will be installed on three feeders between Waverley & Rose Bay Zone Substations.

Both these systems will be installed by the Ausgrid Transmission Mains group in Sydney.

1.3.3 Analysis and Results

All data from the SGSC trial will be made available via the Information Clearing House. For this MMR only sample data sets can be made available.

Data gathered

Merewether DTS

During September 2012, the AP Sensing device was installed at Merewether STS. Integration is complete and live data are available. Calibration and commissioning of this unit is scheduled for October 2012. The device will be used to measure losses through the fibre splicing at Merewether STS.

The following charts show results to confirm fibre optic cable condition. Note that the spikes shown in the Loss Trace chart correlate with splicing joints along the fibre.

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Figure 2. Temperature results

The first graph plots temperature over the length of the underground power cable at 1 meter increments. The temperature is higher initially as the cables are collocated with other power cables that mutually heat the cable. The spikes represent splicing points affecting the readings and will be calibrated out so that the line is smooth for the baseline. The temperature can then be determined against the load to measure the actual performance of the cable against its designed performance. Preliminary Results

The analysis is an indicative assessment of cost to deploy an integrated DTS system throughout the Ausgrid network. A detailed study will be required prior to the production of a cost / benefit analysis to determine the feasibility and advantages of such a system in the wider context.

Assumptions

When analysing this data in relation to DTS capabilities and costs, there are a number of assumption identified that could only be resolved during a physical audit process:

• Number of feeders sharing common ducts with single DTS fibre placement. For the purpose of this exercise, the worse case scenario of 1 fibre per feeder has been used

• Number of feeders that can be marshalled into a single monitoring unit. Units may come with the capacity of between 1 and 12 channels with each channel supporting 1 fibre. Calculation assumes 8 feeders can be monitored per device

• Unit costs differ significantly. Figures used in this analysis relate to the AP Sensing solution installed at Merewether for approximately $185k for 8 channels (8 incoming fibres)

• It is assumed that the substation layout and feeders are marshalled in such a way that the number of locations where you would need to install DTS monitors can be minimised • Dynamic rating costs (that is, the cost of modelling the cable configuration in order to

calculate the temperature in the core of the power cables) are not included in this estimation. Current costs are $6,500 per thermal section. The 2 feeders at Merewether are defined with 3 thermal sections each

Costs to saturate the network for Static Ratings

The following demonstrates a preliminary assessment of the cost to cover all Ausgrid network cables installed with DTS capability, taking into account the assumptions from above:

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Capital Cost

• Unit cost - $ 180k

• Unit implementation cost - $ 100k (Ausgrid BAU business groups) • Number of feeders per DTS unit - 8

• Number of cables - ~300 [210 (33kV) + 92 (132kV)]

• Total cost for implementation - $ 10.5M [(300 / 8 x (180 + 100)]

In addition, costs for (FTE) project resources and development costs for integration and data distribution should also be factored in.

Operational Cost

Depending on the final scope of the deployment, operational costs could include some of the following:

• One or two full time equivalent resources, with appropriate expertise, to operate and maintain the system

• Server and infrastructure costs

• Cost of business groups for maintenance activities

• Maintenance & Support contracts for DTS systems – Undetermined at this point

Dynamic ratings

The previously mentioned assumption also applies for dynamic ratings. Due to the costs involved the project is looking for internal sponsorship.

A Statement of Work from a real time ratings software provider, were received amounting to $200k. The solution will allow the thermal sections to be configured internally (expected by June 2013).

1.3.4 Lessons Learnt

During the course of engagement with Ausgrid's business groups, including Transmission Mains, Mains Design and Rating & Supply Quality groups, it was determined that their business

requirements, particularly supportability and operations-readiness, could not be met directly with the technology that is currently available on the market. In identifying the legacy systems on the network and the future projects that suppliers were already contracted to deliver it was determined that the data that was available and would be available would probably be of minimal value.

Ausgrid has been deploying DTS systems within its network for about 10 years now. Over this time Ausgrid:

• Has deployed two different brands of DTS on the network, each requiring its own supporting software. Ausgrid plans to install two new brands of DTS

• Did not engage any system support capability as it was not available. Support relied on individual relationships and was driven by the data recipients, not the support groups The SFM project engaged Ausgrid's business groups, including Transmission Mains, Mains Design and Rating & Supply Quality group and it was found:

• Of the two legacy systems identified, one was faulty and had to be sent back to the UK for repair and re-calibration. The other in City South was not being used at all

• There had been no apparent attempt or plan to integrate the systems into a centralised model of support and data processing

• Each system (with exception of a portable unit) required at least one complete 19" rack within the substation control room

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Smart Grid, Smart City Monitoring and Measurement Report III – Substation Feeder Monitoring 11 • There was no capability for a centralised real-time rating function. Each system supplied its

own ratings software, with associated multiple and parallel licence fees and software support processes

The SFM project decided to go out to tender for both the monitoring system and the real time ratings function. The objective was to determine the market's capability to provide a fully integrated system that could be scaled through Ausgrid's network.

Three observations relate to current system deployment of DTS systems within Ausgrid: • There were no current support contracts for legacy systems

• Technology selection is not controlled and there are a number of different systems being introduced onto the network

• There is no current capacity to manage the integration of all of the deployment into a single, centrally managed system

With these learnings in mind, test plans and experiments have been constructed to ensure that these points are being addressed.

1.3.5 Case studies

When assessing the DTS supply market it was determined that suppliers of equipment do not attempt to integrate their systems. This makes it very difficult to manage these systems centrally. In this situation, no real time or event processing (with the exception of some alarming) could be achieved. The project team therefore constructed a technical specification for the tender that required the supplier to integrate into existing backend systems. The AP Sensing device at Merewether STS was chosen for this tender. Integration of the device has been achieved to allow the following:

• Data dissemination to anywhere on the Ausgrid IT network • Centralised management and control

• The supplier will be able to remotely log-in and support the system from Germany; and, • Other systems can be integrated into a standard platform

• Minimal equipment located in the Zone Substation (reduces overall capital and operational costs)

1.3.6 Next steps

• Complete installation and commissioning at Merewether STS to trial the portable Sensornet and the AP Sensing fixed unit in a controlled environment on feeders to Newcastle CBD ZN and Carrington ZN

• Complete test plan and perform testing regime at Merewether STS • Continue assisting with the development of standards for network design

• Produce report and recommendations for future work including the development of cost / benefit analysis including:

o Identify feeders suitable for applying DTS technology (audits required)

o Technology selection and identification of supply chain and appropriate industry

support models

o Preparation of a business case identifying savings, CAPEX, OPEX and resource

requirements and the development of work schedules

• Assist with the integration of new DTS systems by Transmission Mains at Kogarah and Rose Bay as requested

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1.4 Dissolved Gas Analysis

1.4.1 Introduction

Ausgrid has roughly 240 major substations (zone substations ZN, and sub-transmission substations STS), most of them with multiple transformers. The expected life of a transformer in a zone

substation is between 30 and 50 years.

Ausgrid manually extracts oil samples from major transformers every 2 years. Laboratory analysis is conducted, covering a range of indicators, including dissolved gasses. The reports typically include:

• Dissolved Gas Analysis – Hydrogen, Oxygen, Nitrogen, Methane, Carbon MonoxideCO, Carbon DioxideCO2, Ethylene, Ethane, Acetylene, Propane

• Other aspects analysed include Water, Acidity, IFT, ES, DDF, Aox, Furans, Passivator The result of this analysis is a measure of the condition of the transformer and is typically of interest to Substation Design and Plant Engineering groups. The presence of, or changes in, dissolved gasses indicate internal changes in the transformer, potentially due to internal faults or the deterioration of seals. Increasing the frequency and availability of dissolved gas information for major transformers will provide more insight into the transformer’s life expectancy, faults and maintenance requirements. The SFM project includes the implementation of GE Hydran DGA monitors in five 11kV Chamber substations. GE Hydran devices provide composite gas and moisture measurements that provide an indication of changes in condition of the transformer.

Figure 3. GE Hydran

1.4.2 Activities

DGA project progress to date:

• Identification of suitable transformers: The transformer selected (Transformer No.3 (T3) at Merewether STS) has long been assumed to have migration of fault gasses from the tap-changer compartment to the main tank (this is a reasonably safe assumption – if the gas levels found in previous manual DGA testing were from the main tank the transformer would have almost certainly failed in service by now). Part of the reason this transformer was selected was to try and learn more about gas migration inside transformers

• Tap-changer gas can potentially mask serious faults, because the gasses are assumed to be being produced in the tap-changer, when they may be produced in the main tank

• Commissioning and integration of a GE Taptrans DGA unit at Merewether STS: Installation and commissioning were completed in September 2011, with the first results being recorded on 13th September 2012. Data is being collected from this date

• Analysis for the data returned from the Merewether STS Dissolved Gas Analysis (DGA) deployment: The Ausgrid Substation design group has been conducting comparative analysis of the data collected to date. A preliminary report has been produced

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Smart Grid, Smart City Monitoring and Measurement Report III – Substation Feeder Monitoring 13 • Twelve units commissioned on 11kV distribution transformers around the central Sydney

are: Integration activities to be completed prior to the data becoming available • Data obtained from an existing deployment on Transformer 3 at the City South Zone

substation (ZN): Project was initiated to investigate the impact of using FR3 (Vegetable oil) in transformers

1.4.3 Analysis and results

Data gathered

A number of manual samples were taken for comparison with the samples recorded online. The exact time and date of the manual samples were noted so that comparison to the nearest online sample could be made.

In addition to the Merewether STS deployment, the City South zone substation DGA unit has been returning data for the previous 3 years. A sample data set is available: MMR3_GA_SFM_DGA Merewether.xlsx.

Analysis

The Merewether STS data has been used to compare and calibrate against the manual testing regime. Discrepancies discovered between the DGA device results and laboratory testing will be further investigated.

The DGA equipment monitors dissolved gasses at 4-6 hour intervals. Although some interesting incidental analysis has been performed, the preliminary view is the equipment has limited value for Ausgrid. A copy of the report is available: MMR3_GA_SFM_Preliminary Report - DGA for

Merewether.pdf. Results

As described in the Preliminary Report in the previous section, there is currently no clear advantage in rolling out DGA to functioning transformers. Asset life is up to 50 years and transformer technology is well established, understood and demonstrably reliable over that time frame. The monitoring system tested relies on electronics and operational procedures to ensure that they remain operable and calibrated, requiring additional internal, and potentially external, support structures. The current sampling interval of every two years is based on decades of transformer failure-analysis and maintenance programs. Scenarios where a higher frequency DGA process (utilising the devices tested) may be appropriate due to exceptions to usual business practices, will be investigated and reported.

Examples where the DGA technology may be more appropriate:

• Monitoring and analysis when trialling new materials (e.g. vegetable oil), equipment or processes

• Increasing the life expectancy of older transformers through more ‘regular’ monitoring • If there is a suspicion of performance issues or fault conditions

The project has demonstrated that without regular monitoring and support, the tested DGA systems provide no advantage over existing technology and processes.

The introduction of inexpensive monitoring equipment, such as the Hydran device in 11kV

substations, is yet to be determined, however, experiences with the installation of these devices in this trial has demonstrated that benefits can be achieved within the current Ausgrid infrastructure and resources.

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1.4.4 Lessons learnt

The current sampling interval of every two years is based on decades of transformer failure-analysis and maintenance programs. Currently, there is little justification to change it. The City South zone substation deployment has been used over the last three years to collect data relating to performance of Vegetable oil in Transformer three. The results from the trial demonstrated that the oil performed as expected and comparable to traditional synthetic oils.

In the example, the plant monitored is far more reliable than the monitoring equipment, which required constant monitoring and maintenance. This reduces the anticipated benefits of the project as current manual sampling and lab testing appear to be both more cost effective and accurate. Having said this, there are benefits in seeing the trend over time when assessing changes in equipment condition. Traditional sampling every 1-2 years typically does not have the resolution of data to permit this type of analysis.

1.4.5 Case studies

None available at this stage

1.4.6 Next steps

• Complete integration of dissolved gas analysis on 11kV Chamber distribution transformers. Although fully commissioned, data will not become available until the communications from the substation to the data centre is achieved. This is expected to be in place October 2012 • Complete analysis of City South zone substation DGA data: The trial for this unit is now

complete and a report has been produced. Permission to publish the report is pending. Servicing of the unit is dependent on whether the Ausgrid business groups want to continue with the trial

• Continue with data collection at Merewether STS

• Address the following aspects of the SFM Data Priorities:

o Reduction in operating cost o Integration to a Smart Grid

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1.5 Distribution Transformer Ratings

1.5.1 Introduction

Transformer rating is defined as the maximum load that the asset may deliver over a sustained period of time without reducing its life expectancy. Distribution transformer ratings are limited by

temperature, as the transformer winding-losses generate heat. At extreme levels the insulation of the transformer windings will damage, leading to eventually failure. When substations are built, a number of assumptions are made in the analysis relating to maximum temperature and the load cycle that will be experienced by the transformer.

Near real time substation load information in conjunction with accurate temperature data has the potential to remove assumption made by planners. Collecting measurement data to built historical trends and converting them into more relevant load profile and asset performance models can give planning engineers better context for decisions around the future.

PowerSense RTUs, installed in a number of low voltage distribution substations (11kV to 415 V), were identified to use to monitor transformer and ambient temperature. The goal is to validate the current transformer ratings model, and where possible improve the utilisation of the substation assets without negatively impacting the equipment’s maintenance and life expectancy. The ability of the

transformer’s environment to dissipate heat affects the transformer rating, and should be taken into consideration when estimating the rating. This analysis has the potential to defer capital expenditure relating to substation replacement or augmentation.

Up to 20 ground substations and 10 pole top substations will be used for this initiative. Sites chosen already have commissioned PowerSense units and have historically shown high loads. Loaded substations will provide the best opportunities for deferring an augmentation or replacement. Appropriate temperature sensors will be connected to each of the selected PowerSense units. Measurement data will be relayed back and stored in a Historian database for analysis. The trial criteria for the selected sensors are:

• Can sensors interface reliably with the existing RTUs (Up to four sensors)

• Can sensors be reliably mounted to transformer surfaces and in airways (ambient) • Minimal effort to install

• Reasonable cost of equipment and installation The following analysis will be undertaken:

• Estimate hot spot temperature (the limiting factor of transformers) using transformer temperature, ambient temperature and transformer load

• Recalculate the transformer Contract Ratings using transformer load profiles and measured ambient temperatures

1.5.2 Activities

• Site selection in progress. Ten sites selected • Procurement of 28 probes completed

• Installation activities commenced. Two sites completed. (1st installation on 21 June 2012 – See photos below)

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Smart Grid, Smart City Monitoring and Measurement Report III – Substation Feeder Monitoring 16 Installation at Substation George Allen No.2

‘Sensor Install Kits’ is provided to technicians so that they install into chosen sites over a period of time

Figure 4. Ring main isolator and PowerSense device at kiosk substation

Attached via cable tie or some other methods to the PowerSense device stand

Figure 5. Ambient temperature sensor

Attached to the top of the transformer on the accessible side (the same side where the nameplate and oil gauge is) via magnetic cable ties.

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1.5.3 Analysis and results

Data gathered

All data from the SGSC trial will be made available via the Information Clearing House. For this MMR only sample data sets can be made available:

MMR3_GA_SFM_DTR S02904.xlsx MMR3_GA_SFM_DTR S08502.xlsx Analysis1

Data analysis was started soon after the first temperature probes were installed. The initial focus is on reviewing sensor choice and placement to ensure optimal data quality. A baseline will be created against which future studies and benefits analysis can be performed.

Average Transformer Load (A) on LV side

The average load shown here is of a typical residential + commercial mix substation, i.e. daily cycles which clearly shows the 5 weekdays (higher load) and 2 weekend days (lower load).

Figure 7. Average Load per Phase

Transformer Temperatures

These are calculated values using Australian standard AS2374 formula for power transformers. These values exclude the substation ambient temperature which is a measured value.

Figure 8. Transformer Temperatures

1_{Data validation and analysis is still work in progress. Drawing any conclusions based on results}

shown here is entirely at the user’s own discretion and risk.

Monday to Sunday

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Utilisation

A reliable method to calculate transformer utilisation is to take the spot load as a percentage of the rated load. However, the real rating is the transformer temperature in its windings and oil. For this reason a metric using temperature will be a better representation of the true utilisation.

The following graph shows the transformer utilisation based on three different metrics, all calculated for the same site. In the case of this example, a lower utilisation is reported when using temperature metrics compared to load based metrics, meaning the transformer is possibly under-utilised.

Figure 9. Transformer Utilisation

60°C from AS2374-2 and 115°C from AS2374-7.

Measured vs. Calculated transformer top oil temperature

The calculated top oil values are much higher than the measured values. It is still unclear which values are more reliable as the sensor position could be incorrect. Further investigation will be performed.

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1.5.4 Lessons learnt

• Early analysis indicates that installing the temperature probe on the top of the transformer casing is not effective in measuring transformer oil temperature. This could be due to internal insulation of the transformer casing, as well as the temperature probe being exposed to the substation ambient temperature. Different contact-type temperature probes will be tested to see if a better result can be achieved

• It is still possible to estimate the transformer time constant by comparing the measured 'transformer' temperature and the substation ambient temperature. At this early stage it appears the generally assumed value of 2.5 hours for the transformer time constant is reasonably accurate

1.5.5 Case studies

1.5.6 Next steps

• Deploy remainder of temperature sensors in alternate locations • Develop analysis scripts for measurement analyses

• Develop a model for extrapolating monitored substation data to non-temperature monitored substations

• Address the following aspects of the SFM Data Priorities:

o Reduction in operating cost o Integration to a Smart Grid o Business case and case study

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1.6 Environmental Monitoring

1.6.1 Introduction

With the deployment of RTUs on the low voltage network, Ausgrid is developing a smart grid platform on which various additional technologies can be deployed. Using the opportunity this presents, the SFM project decided to test a number of environmental monitoring devices in some of the distribution substations. This supports the SFM data priorities by investigating opportunities to reduce operating costs while integrating with other smart grid technologies.

The following types of environmental monitors were selected: Sensor Description Application

Temperature/Humidity Monitoring of temperature and humidity in distribution substations in order to create more advanced models of asset ratings and asset life expectancy. Leverage the PowerSense RTU.

Air Flow Monitoring of chamber substations which have continuous forced

ventilation in order to achieve a higher rating for the substation. Flood

(i.e. inundation by water)

Early detection of substation flooding in order to avert potential equipment damage. Leverage the TransformerIQ RTU

Table 2. Environmental Monitors

1.6.2 Activities

Temperature/Humidity Sensors

To date, one humidity and four temperature sensors have been installed:

• A temperature and humidity sensor was installed on a Pole Transformer in Mayfield to prove the concept

• At Mt Hutton Shopping Centre a temperature sensor was installed to monitor the ambient temperature in a chamber substation

• Two temperature sensors were installed in George Allen No. 2, one to monitor ambient temperature and the other to monitor external temperature of the power transformer • Data is being collected and stored in the Historian

Air Flow Sensor

• A Weber Vent Captor Flow Switch, used for air flow monitoring, was tested with PowerSense in a laboratory environment. The sensor was found to

operate satisfactorily, but was found to be unsuitable for a substation environment after one of the ceramic plates used to detect air flow was damaged in the office

• An air flow sensor from a different manufacturer was identified and also tested with satisfactory results

• In the search for a suitable substation to test the device, only one chamber substation with continuous forced ventilation could be identified in Ausgrid's network. Special access is required for this

substation and it currently does not have a RTU installed. Further work on the air flow sensor will not be performed due to the limited application of this technology in Ausgrid’s network. Instead of a field trial, the laboratory results will be used

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Smart Grid, Smart City Monitoring and Measurement Flood Sensor

• A successful trial installation took place at Gadigal Lachlan substation using the

TransformerIQ RTU. The device was removed again after confirming it operated correctly as this substation is unlikely to flood

• A site has been identified with a

the commissioning of the TransformerIQ RTU

1.6.3 Analysis and results

Data gathered

All data from the SGSC trial will be made available via the Information Clearing House. For this MMR only sample data sets can be made available:

MMR3_GA_SFM_Environmental HS39614 Temperature.xlsx

MMR3_GA_SFM_Environmental HP13102 Temperature & Humidity.xlsx Analysis

Early observations clearly indicate a seasonal pattern; however the actual values are influenced b the devices within the substation and the recorded temperatures are typically above the outside temperate. Data has been collected, with further analysis still to be undertaken.

1.6.4 Lessons learnt

Airflow sensor: Despite the requirements that were considered in the equipment selection, the air flow sensor was not physically robust enough that we could be confident they would be successfully installed in a substation without being damaged. Further investigation would be required to find a unit robust enough for the substation environment.

1.6.5 Case studies

1.6.6 Next steps

• Flood Sensor: Install a flood sensor at corner Sussex &

TransformerIQ RTU has been commissioned; analyse the data received from the sensor; document any lessons from the install and operation of the equipment; consider the operational cost benefits

Monitoring and Measurement Report III – Substation Feeder Monitoring

A successful trial installation took place at Gadigal Lachlan substation using the

TransformerIQ RTU. The device was removed again after confirming it operated correctly as ubstation is unlikely to flood

A site has been identified with a high risk of flooding for an installation. Currently waiting for oning of the TransformerIQ RTU

All data from the SGSC trial will be made available via the Information Clearing House. For this MMR le data sets can be made available:

Environmental HS39614 Temperature.xlsx

Environmental HP13102 Temperature & Humidity.xlsx

Early observations clearly indicate a seasonal pattern; however the actual values are influenced b the devices within the substation and the recorded temperatures are typically above the outside temperate. Data has been collected, with further analysis still to be undertaken.

Figure 11. Substation Ambient Temperature/Humidity

Airflow sensor: Despite the requirements that were considered in the equipment selection, the air flow sensor was not physically robust enough that we could be confident they would be successfully

talled in a substation without being damaged. Further investigation would be required to find a unit robust enough for the substation environment.

Flood Sensor: Install a flood sensor at corner Sussex & Goulburn substation once the TransformerIQ RTU has been commissioned; analyse the data received from the sensor; document any lessons from the install and operation of the equipment; consider the operational cost benefits from the use of this equipment

21 A successful trial installation took place at Gadigal Lachlan substation using the

TransformerIQ RTU. The device was removed again after confirming it operated correctly as high risk of flooding for an installation. Currently waiting for

All data from the SGSC trial will be made available via the Information Clearing House. For this MMR

Environmental HP13102 Temperature & Humidity.xlsx

Early observations clearly indicate a seasonal pattern; however the actual values are influenced by the devices within the substation and the recorded temperatures are typically above the outside

Airflow sensor: Despite the requirements that were considered in the equipment selection, the air flow sensor was not physically robust enough that we could be confident they would be successfully

talled in a substation without being damaged. Further investigation would be required to find a unit

substation once the TransformerIQ RTU has been commissioned; analyse the data received from the sensor; document any lessons from the install and operation of the equipment; consider the

(22)

Smart Grid, Smart City Monitoring and Measurement Report III – Substation Feeder Monitoring 22 • Temperature/Humidity: Continue analysis of temperature and humidity data; consider the

impacts of dynamic ratings on distribution transformer specifications; how will this impact on ratings, how will nameplate ratings be interpreted

• Temperature/Humidity: Work with planning groups to identify additional uses for this equipment; consider the operational cost benefits from the use of this equipment

(23)

Glossary of Abbreviations

Abbreviation Term

AVVC Active Volt-VAr Control DGA Dissolved Gas Analysis

DM&C Distribution Monitoring and Control DTS Distribution Temperature Sensing FTE Full Time Equivalent

LAN Local Area Network

MPLS Multiprotocol Label Switching RTU Remote Terminal Unit

SCADA Supervisory Control And Data Acquisition STS Subtransmission Station

Smart Grid, Smart City Project