• No results found

A Case Study on SCADA Implementation in 220 kV Substation

N/A
N/A
Protected

Academic year: 2022

Share "A Case Study on SCADA Implementation in 220 kV Substation"

Copied!
11
0
0

Loading.... (view fulltext now)

Full text

(1)

A Case Study on SCADA Implementation in 220 kV Substation

Vinuta V Koluragi

1

M.Tech(Power and Energy Systems) Assisstant Professor

B.L.D.E.A’s V P Dr P. G. Halakatti College of Engg. & Tech., Bijapur.

ABSTRACT

Development of nation depends upon electricity energy and at present scenario there is large gap between electric generation and load. This gap can be filled with proper control, monitoring and coordinating the distribution components at power sector. In this view, Automation of power distribution system has increasingly been adopted by power utilities worldwide in recent years. As part of its efforts to provide a more reliable supply to the customer and to enhance operational efficiency, the automation of the power system can be achieved by SCADA (Supervisory Control And Data Acquisition). It is a boon to the automation concept of dynamic technology. Karnataka Power Transmission Corporation Limited (KPTCL) has undertaken steps to automate existing substation and new substation by use of most advanced controlling and monitoring technology ABB SCADA. Karnataka Power Transmission Corporation Limited, presently with the help of SCADA covers major generating stations and Independent Power Producers (IPP), receiving stations ranging from 33kV to 400kV, collects data from all feeders from 11 KV to 400 KV, upgrades information to Load Despatch Center (LDC). Real time data acquisition from all interface points by SCADA, helps to perform energy billing, energy audit and Availability Based Tariff (ABT) functions, and Sub-system to perform Open Access operations.

Keywords: Real Time Monitoring and Controlling, SCADA, RTU, ABT.

NOMENCLATURE

SCADA : Supervisory Control And Data Acquisition RTU : Remote Terminal Unit

ABT : Availability Based Tariff

1. INTRODUCTION

Karnataka Power Transmission Corporation Limited is a registered company under the Companies Act, 1956 was incorporated on 28-7-1999 and is a company wholly owned by the Government of Karnataka with an authorized share capital of Rs. 1000 crores. KPTCL was formed on 01-08-1999 by carving out the Transmission and Distribution functions of the erstwhile Karnataka Electricity Board [5].

Present day power systems have large interconnected networks. The success of the recently evolving electricity market structure will heavily depend on modern information systems and online decision tools. Maintaining system security, reliability, quality, stability and ensuring economic

operation are the major operating concerns. Online monitoring, operation and control of the modern day power systems have become impossible without computer aided monitoring & dispatching systems. The basic requirement to fulfill these needs is SCADA.

The ability to perform operations at an unattended location from an attended station or operating center and to have a definite indication that the operations have been successfully carried out can provide significant cost saving in the operation of a system. This is exactly what is achieved through the SCADA system. A formal definition of SCADA system, as recommended by IEEE [1], is “A collection of equipment that will provide an operator at a remote location with sufficient

(2)

information to determine the status of particular equipment or a process and cause actions to take place regarding that equipment or process without being physically present”.

SCADA provides open architecture rather than a vendor controlled proprietary environment. It interfaces hardware and software, and it includes functionality such as trending, alarm handling, logging archiving, report generation, and facilitation of automation. Thus SCADA has been used has powerful tool for power system automation, that refers to automatic switching, regulating, controlling, logging, protection etc. of electric power flow without human intervention.

2. SCADA IMPLEMENTATION IN 220KV SUBSTATION

200/110/11kV Shivgiri substation Bijapur is newly installed substation. Under IES project, automation of new substation is done through Substation Automation System (SAS) using IEC 61850. The functions performed by Substation Automation (SA) system are in, general, switch control, data monitoring, protection etc. In IEC-61850, these functions are broken into low-level functions called sub-functions. Each sub-function is performed by the IED installed in the substation. Each IED can perform one or many sub functions. A set of sub-functions is integrated together to realize a substation automation function. These communicate with each other through Local Area Network in the substation. Specific syntax and semantics are defined for communication between sub-functions. All the possible sub-functions have been standardized in IEC- 61850.Information produced and required by each substation is given in the IEC-61850 standard [1].

The sub functions are assigned at three levels as shown in figure 1: (i) Process level (ii) Bay level (iii) Station level

Fig 1: Levels defined in IEC 61850 [1]

2.1 Process Level Function: extracts the information from sensors/transducers in the substation and to send them to upper level device, called bay level device. The other major task of process level function is to receive the control command from bay level device and execute it at the appropriate switch level.

2.2 Bay Level Functions: acquire the data from the bay and then mainly act on the primary (power circuit) equipment of the bay. The different conceptual subparts of a substation are encircled by line in figure 2.

Station Level Functions: are of two types.

2.2.1 Process Related Functions act on the data from multiple bays or substation level database. These functions are used to submit the control commands for the primary equipment (Circuit breakers) and collect the substation data like voltage, current, power factor etc. from the bay level devices. Each bay includes one primary equipment such as transformers, feeders etc.

2.2.2 Interface Related Functions enable interactive interface of the substation automation system to the local station operator HMI (Human Machine Interface), to a remote control centre for monitoring and maintenance.

There are basically two types of equipment in a substation:

(i) Primary equipment’s and (ii) Secondary equipment’s.

2.3.2.1 Primary Equipment’s Include

Fig 2: Conceptual Substation Bays [1]

transformer, switchgear etc. Secondary equipments include protection, control and communication equipments. Further, secondary equipments are categorized into three levels in IEC- 61850 standards. These are station level, bay level, and

(3)

process level equipments. A conceptual substation automation system based on the IEC 61850 standard is evolved and depicted in figure 3.

Fig 3: Conceptual Substation Automation Topology [1]

With this conceptual view at 220kV substation Bijapur there are 8 bays divided. Control and monitoring operation is carried out both remotely and locally. At substation 4 IEDs are used for collecting information and OFC is used for local communication, for remote communication Ethernet and VSAT is used. SAS consists of Bay Control & Protection Panel and Protection Panel, they are manufactured by ABB.

Control & Relay panels and Protection panel are inbuilt in ABB panel.

2.2.2.2. SCADA Equipments to Substation:

220/110/11kV substation control room is provided with Bay Control & Protection panel and Protection panel by ABB. All the ABB panels are equipped with 4 IEDs used for protection and control. ABB’s IED 670 series provides reliable, efficient and flexible protection, monitoring and control for all applications in sub-transmission and transmission systems.

IED provides a common powerful hardware platform and an extensive hardware-independent, modular function library.

Setting, commissioning and maintenance procedures of all IED are fast and simple. All are similar hence user can learn about one to know them all. These can communicate easily with IEC61850.

List of Intelligent Electronic Device (IED) 670:

1. RET670-Transformer Protection IED.

2. REC670-Bay Control IED.

3. REL670-Line Distance Protection IED.

4. REB670-Busbar Differential Protection IED.

RET670-Transformer Protection IED: It is used for reliable protection & control of all types of power transformers and reactors. Also it provides protection solution for any type of transformer & shunt reactor application. It gives freedom to select functionality according to our needs, basic functionality is included and pre configured. A single RET670 can integrate complete protection & control functionality for a transformer

& a connected transmission line. The distance protection function can also be used as back up protection for faults with in transformer & in connected lines. In all, RET670 increases reliability and profitability of entire power system. Figure 4 shows RET670 IED.

Fig 4: RET670-Tansformer protection IED [8]

It is designed to operate correctly over a wide frequency range in order to accommodate power system frequency variations during disturbances. RET670 features also several function for local and remote apparatus control on all sides of transformer.

It provides a large HMI for local control and instantly accessing important data, such as settings, events and disturbance information. 30 apparatuses can be controlled and visualized. Large HMI provides overview of quick status of substation with position indications and service values [6].

REC670-Bay Control IED: It provides optimized control and reliable operation of switch yard. It provides pre configured control solution for any type of switch gear and different switch gear configuration. REC670 enables the manual control of a tap-changer from a Substation Automation system. It also integrates advanced voltage control for transformers in a substation in a single IED. This eliminates the need for dedicated voltage control devices in cases where the transformer protection is not equipped with voltage control.

The REC670 IEDs feature a large HMI for local control and instant access to important data, such as settings, events and disturbance information. The control is based on the select before operate principle to ensure secure operation and to avoid human mistakes. Control screen can be selected as

(4)

default screen. Control commands can be directly executed and important measurements can be read. All measurements are available in IED can be shown on HMI. Graphical display can be configured as it is at substation. Figure 5 shows REC670 IED.

Fig 5: REC670 -Bay control IED [8]

REC670 is able to handle a large number of analog signals from CTs and VTs. The outstanding I/O capability enables control of several bays with complete measurement with only one IED. One REC670 IED is capable of handling control of all apparatuses in one entire diameter in 1 ½ breaker arrangement including breaker failure protection for all breakers [6].

REL670-Line Distance Protection IED: It provides versatile protection, monitoring and control functionality with maximum flexibility and performance optimized for transmission overhead lines and cables. The powerful IED provides distance protection for double circuit, parallel operating and series compensated lines. REL670 IEDs are able to protect and control several objects, for instance a combination of a line and a transformer with a single IED. As a result, this IED increases both the reliability and profitability of entire power system. REL670 provides both customized and pre-configured protection solutions. The pre-configured IEDs are equipped with complete functionality adapted for four different configuration alternatives: single pole breaker or multi-breaker arrangements with single or three phase tripping. Figure 28 shows REL670 IED.

REL670 provides protection of power lines with high sensitivity and low requirement on remote end communication. Measurements and setting of all five zones with six setting groups are made completely

Fig 6: REL670-Line distance protection IED [8]

independent, which ensures high reliability for all types of lines. The distance and earth-fault protection functions can communicate with remote end in any communication scheme.

It offers full control and interlocking functionality required for control of apparatuses in a substation. The integrated HMI allows secure and quick local control for stand-alone applications and provides back-up control for substation automation systems. REL670 provides efficient substation automation solutions in terms of performance, redundancy and cost for any high voltage application [6].

REB670-Busbar Differential Protection IED: It is designed for the protection and monitoring of bus bars. REB670 protects single and double bus bars with or without transfer bus, double circuit breaker or one-and-half circuit breaker arrangements. It provides selective, reliable and fast fault clearance for all types of internal phase-to-phase and phase-to- earth faults in solidly earthed or low-impedance earthed power systems. At the same time, it maintains complete stability for external faults, even when heavy CT saturation occurs. It can also handle all internal multi-phase faults in isolated or high- impedance earthed power systems [6]. Figure 7 shows REB670 IED.

Fig 7: REB670-Bus bar differential protection IED [8]

2.2.2.3. SCADA Connections:

(5)

At 220/110/11kV substation, Substation Automation System (SAS) consists of 27 panels for protection and bay control.

Layout of panels at control room is shown in figure 8.

• B&P - Bay Control & Protection Panel

• P - Protection Panel

• BBA - Bus Bar Protection Panel

• INDI 1 – Indi line 1

• INDI 2 – Indi line 2

• TRF 1 HV – Transformer 1 HV side

• TRF 1 LV – Transformer 1 LV side

• TRF 2 HV – Transformer 2 HV side

• TRF 2 LV – Transformer 2 LV side

• BGD 1 – Basavan Bagewadi line 1

• BGD 2 – Basavan Bagewadi line 2

For SAS

220kV line

110kV line

11kV feeder

Fig 8: Layout of panels at Control center at 220/110/11kV substation

IES project provides Ruzzegged com (Ethernet) Switch, 3 personal computers – DRPC, SAS1 and SAS2, printer, event list recorder and for communication VSAT, OFC. Connection of ABB panels is shown in figure 9. There are 8 bays at substation; at each bay have one ruzzegged com switch which connects all bay information to main SAS through OFC.

Information from SAS can be monitored and controlled locally and also information is sent to Master Control center (MCC).

Fig 9: Connection of ABB panels at substation As shown in figure 9 communication network used is Star- Ring topology. This topology has potential to provide time delay within allowable range and also offers the better reliability of the process bus.

2.2.2.4. SCADA Operations:

Local operator at substation control room observes and monitors 220kV, 110kV and 11kV lines. Single line diagram monitoring screen display of 220/110/11kV, 110kV and 11kV line is shown in figure 10(a), 10(b) and 10(c) respectively.

Overview of 220/110/11kV substation Bijapur is monitored by monitored by operator at control room. Same single line SAS

SUX Station Auxiliary

Bay Control

Panel

2BBA1 220kV Bus

Bar Protection

Panel

2BBA2 220kV Bus

Bar Protection

Panel

I N D I 1

P I N D I 1 B

&

P I N D I 2 P

I N D I 2 B

&

P

Bus Coupler

B&P

T R F 1 H V B

&

P T R F 1 L V B

&

P

BGD 2 P

BGD 2 B&P

BGD 1 P

BGD 1 B&P

TRF 2 HV B&P

TRF 2 LV B&P

11kV Bank B&P

10 MAV TRF HV 110/11kV

110kV BGD B&P

110kV Bus Coupler IE 2

B&P

Bijapur B&P

IE 1 B&P

Feeder 1&2 B&P

Feeder 3&4 B&P

Feeder 5&6 B&P

(6)

diagram is displayed at remote control center. In single diagram display of SCADA screen symbols of Lighting Arrestor (LA), Gang or Group Operated switch (GOS) and Circuit Breaker (CB) are used. Table 1 shows symbols used for SCADA.

Table 1: Symbols used in SCADA Screen

Fig 10(A): Single Line Diagram Display of 220/110/11kv Line at Control Room

Fig 10(B): Single Line Diagram Display of 110kv Line at Control Room

Fig 10(C): Single Line Diagram Display of 11kv Line at Control Room.

At present operator at substation operates 11kV circuit breakers at control room. He note down the measurement values displayed on monitoring screen as shown on figure 11.

Real time values are noted at every one hour and daily load is generated. Also SAS provides facility of event recording and alarms for operator.

There is also facility to operate GOS remotely. With the help of IED fault can be recorded. 100 disturbance records can be maintained with time and date. Indication during disturbances is displayed which helps operator to carry out precaution or solve the problem.

Sl No.

Equipment Symbols Identity No.

1 Lighting Arrestor (LA) grounding

89CE

2

Gang or Group Operated

switch (GOS)

89D

3 Circuit Breaker

(CB)

52

(7)

Fig 11(a):220kV measurement values.

Fig 11(b):110kV measurement values.

Table 2 gives the incoming and outgoing voltage, current, active & reactive power, power factor and frequency observed on 220kV measurement monitoring screen on 07/07/2011 time 11.00.08.

2.3. Load Despatch Center:

Load Despatch Center (LDC) is the hub for load despatch and control, it requires acquiring all data from generation and substation to match generation and load. LDC requires data with respect to available generation and load to be attended.

As such real time data is required from all Generating stations;

real time data is required from receiving stations; real time data is required from Interface points from where power is delivered to Distribution companies or Consumers. LDC also has to exercise control over the receiving stations, and consumers and if necessary the Generators also. As such, Supervisory control is required to shed loads by opening a

breaker, Supervisory control is required switch off or switch on a consumer, Supervisory control is required to control the generation as and when control is extended.

Scenario of power system without control centers:

 There was no Grid Discipline.

 Due to indiscipline there was problem of low voltage and low frequency.

 There were frequent Grid failures.

 Non optimum utilization of available resources.

 There was no real time availability of data/ events occurring.

 Inefficient Power System Operation & Load Management

 Due to no regulation wide gap in Demand - Supply position.

 Low voltages at Consumer end.

To overcome all problems India undergone Grid Discipline through SCADA. In this view all Generation station, receiving station and distribution station were integrated in project. Thus data from 110kV & 220/110/11kV substation Bijapur are sent to LDC for further operation. LDC’s architecture, function is briefly explained in this section.

Indian Power System Load Despatch Centers is divided into

 At National level

 National Load Despatch Centre (NLDC)

 At Regional Level

 Five Regional grids

 Regional Load Despatch Centers (RLDC)

 At State Level

 State Load Despatch Centre (SLDC)

 SLDCs at each state

A typical architecture of an Energy management system is shown in figure 12.

Table 2: 220Kv Measurement Monitoring Values

(8)

Fig 12: A Typical Architecture of an Energy Management System

As shown in figure 34 data collected from all substations through SAS or RTU is sent to Area control center (ACC) and then same data is communicated to Regional Control Center (RCC).National control center will look after the whole grid.

There are 5 Regional Load Despatch Center, they are

 Northern Regional Load Despatch Center (NRLDC)

 Eastern Regional Load Despatch Center (ERLDC)

 Southern Regional Load Despatch Center (SRLDC)

 Western Regional Load Despatch Center (WRLDC)

 Northern Eastern Regional Load Despatch Center (NERLDC)

Southern region consists of 5 State Load Despatch Centers, they are

 Pondicherry

 Tamilnadu

 Kerala

 Karnataka

 Andhra

Central generation plants, State generation plants and Independent Plant Producers (IPP) connect to common Power Grid of India. As objective of LDC is to match generation and DATE

07/07/2011

TIME 11.00.08

INDI-1 201

INDI-2 202

BC 203 TRAFO- 1 204

BGWD- 1 206

BGWD- 2 207

TRAFO- 2 208

Voltage in kV

Vry 215.01 214.67 215.02 215.16 215.05 214.48 215.18

Vyb 217.42 217.59 217.76 217.37 217.63 217.21 217.37

Vbr 213.46 213.22 213.45 213.13 214.17 213.67 213.75

Current in Ampere

L1 0.00 87.40 0.00 50.23 186.78 0.00 49.56

L2 0.00 89.90 0.00 51.67 192.67 0.00 51.32

L3 0.00 91.26 0.00 50.48 191.50 0.00 49.75

Active power

MW 0.00 30.55 0.00 17.97 -66.39 0.00 17.75

Reactive power

MVAR 0.00 13.54 0.00 5.95 -25.57 0.00 5.87

Power factor

0.00 0.91 0.00 0.95 0.93 0.00 0.95

Frequency Hz 49.91 49.90 49.9 49.90 49.90 49.90 49.89

(9)

load, there is need to continuously monitor and control.

Karnataka states Load Despatch Center is situated at Bangalore. At SLDC Control center, Grid connection of southern region is observed. Role of SLDC is to collect information from electrical companies of Karnataka and send data to SRLDC. Generation and load of state is monitored and controlled by SLDC. SLDCs send the requisition of load to the SRLDCs, against their entitlements out of available power from Central Sector Generation and the SRLDCs allocate total available power to various states in the ratio of their entitlements. According to available power SLDCs schedule power for state previous day & ESCOMs had to operate according to schedule. If there is any problem at generation then it informed to SLDCs by revising. SLDCs control state generators according to load. Data acquired at SLDC is used for Energy auditing, Energy billing and Availability Based Tariff (ABT).

SRLDC collects data from SLDC and controls Central Generation. NLDC monitors all SRLDC and communicate with Central electricity Authority (CEA).

2.3.1. SCADA Application at LDC:

1. Network application overview: The SCADA systems caters to the whole of Karnataka state which has five Distribution companies and 23 major generating stations and major IPP’s and Central Generation Share. Figure 35 shows monitoring screen at control center for Karnataka state.

Fig 13: Monitoring screen for Karnataka state LDC [4]

At LDC, operator can observe generation, power flow, schedule and actual energy available etc as depicted in figure 13.

2. Open Access Monitoring: IPP can go for open access if they wish SCADA also provides information about open access monitoring screen for operator.

3. ABT monitoring Screen: At KPTCL tariff is basically classified into 3 components, they are; Energy consumption, Maximum demand and Unscheduled Interruption (UI).

UI component is dependent on frequency, when load exceeds generation frequency decreases depend on decrease in frequency additional charges are penalized. Figure 14 shows ABT Monitoring Screen at control center. UI charges are decided by CEA.

Fig 14: ABT Monitoring Screen [4]

As SCADA is integration of hardware and software, care must be taken that there exist proper synchronization between them.

RTU 560A at 110/11kV substation City Bijapur is digital equipment no maintenance is required but proper cleaning of panel has to be carried out. Minor work for adaptability of SCADA at 110/11kV substation were improvement of earthing, Restoration of control desk (this includes, providing indication lamps, closing coils and TNC switches) and Wiring of breaker position indication in 11kv.

2.4. Maintenance:

Improvement of earthing is done by providing one CI pipe electrode as per KPTCL standard CI earthing 50 x 6 mm MS flat for connection to earth mat 50 x 6 mm GI flat for raisers new RTU is connected to same earth with other C&R panel.

Figure 15 shows connection for improvement of earthing.

(10)

Fig 15: Connection for improvement of earthing When earth mat is not provided at substation, earth resistance for SCADA has to note down after installation work at particular substation. Table 3 gives SCADA earth resistance at 110/11kV substation Atarga during visit with ABB committee on 08/07/2011. UPS for RTU 560A will under go test for battery back up condition.

Table 3 : Earth resistance for SCADA Sl No. Equipment Resistance in Ω/V

1 SCADA CI Pipe 0.28Ω/0.6V 2 VSAT GI pipe 0.29Ω/0.6V 3 RTU Panel 0.23Ω/0.5V 4 C&R panel 0.25Ω/0.4V

5 110kV TRF 0.6Ω/0.9V

6 11kV TRF 1.0Ω/0.9V

3. CONCLUSION

Power Systems are large complex systems covering vast areas National grids and highly nonlinear, high order system. Many process operations need to be coordinated and millions of devices requiring harmonious interplay. The Energy flows from various Generating stations to various Receiving Sub stations via Transmission networks. On line monitoring, operation and control of the modern day power systems is required for maintaining system security, reliability, quality, stability and ensuring economic operation,. The basic requirement is of power system automation which is achieved by SCADA.

SCADA covers major generating stations and Independent Power Producers (IPP), receiving stations ranging from 33kV to 400kV, collects data from all feeders from 11 KV to 400 KV, upgrades information to Load Despatch Center (LDC).

Real time data acquisition from all interface points by SCADA such as voltage, current, frequency, active power, reactive power and power factor. Operators at all substations will send their respective load and energy required to the LDC. LDC sends the required total load required by to SRLDC. SRLDC according to available generation prepares load schedule and send to LDC, this schedule must be followed by all stations.

During generation failure, availability of generation will be updated to LDC; LDC will inform further it to all substations so that proper load control can be carried out without any interruption of power. In this way the total grid can be observed and controlled, thus large gap between generation and load is reduced. It also helps to perform energy billing, energy audit and Availability Based Tariff(ABT) functions, and Sub-system to perform Open Access operations at LDC.SCADA has facilities to record data, event list, disturbance records, and trip values during fault etc., with help of these facilities operator at substation can analyze fault, if any mistakes in recording readings can be easily sorted out.

Thus concluding that a full fledge SCADA system is very much necessary for monitoring, controlling, fault detection and prevention and to make restoration power supply activities easier and faster.

REFERENCES

[1] KPTCL training report “Remote Substation Monitoring And Control through SCADA”, 05-09 October 2009.

[2] Paper presented

[3] Martin Chartrand, “Dual Redundant Controller Systems”, Control Microsystems White Paper, October 2004.

[4] Chandrashekar, Mallakkappa S “Integrated Extended SCADA project KPTCL” IES Summary, October 31 2007.

[5] Manuals and website [6] ABB RTU 560A Manual.

[7] www.kptcl.com and www.abb.com

BIOGRAPHY

Ms. Vinuta V Koluragi was born in Bijapur, Karnataka, India. on 13th July 1987. She obtained B.E degree in Electrical & Electronics from B.L.D.E.A’s

(11)

Bijapur under VTU, Belgaum. She obtained M.Tech degree in Power & Energy System from BEC Bagalkot under VTU, Belgaum.

She is currently working as Assisstant Professor at B.L.D.E.A’s V P Dr P. G. Halakatti College of Engg. &

Tech., Bijapur. Her areas of interest are Renewable Energy Systems, PLC and SCADA,Control Systems, Power systems.

References

Related documents

[r]

This study examined specific matching of market orientation and innovation strategy as functional level strategies or capabilities in determining better performance

With the used Bluetooth sticks, a up to three slaves can be connected to a master and a maximum data rate of 86 kb/s is achievable from slave to master and 9 kb/s from master to

One can do this because, remember, demand curves reflect consumers’ marginal utilities, while supply curves reflect producers’ marginal disutilities (costs) of production; and the

 Section 3 (1), Government of India (GoI) shall, from time to time, prepare the National Electricity Policy and Tariff Policy, in consultation with the State Governments for

The findings may guide future policy and practice reforms within the wider early childhood field, and may be of particular use to other undergraduate ECEC

However, according to Desai (2012), develop- ing countries still lack the tools and systematic strategies to deliver secure land rights for all. A problem specific

What we are learning, now, after years of empirical research is that Filial Therapy, a family focused play intervention that uses the relationship with the primary caregiver, is