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Application of IEC 61850 at Palmridge substationByFhulu MatebaloSubmitted in preliminary fulfilment of the requirements for the

BTECH: ELECTRICAL ENGINEERING POWER

UNIVERSITY OF SOUTH AFRICACOLLEGE OF SCIENCE, ENGINEERING AND TECHNOLOGYDEPARTMENT OF Electrical and Mining Engineering

ProposalDate: 18 March 2014

TABLE OF CONTENTS1.1INTRODUCTION21.2RESEARCH STATEMENT31.3research question31.4aim of research41.5value of research41.6research objective51.7literature review pertaining to research question51.8RESEARCH METHODOLOGY71.8.1Research Approach81.8.2How research instrument developed81.8.3Data collection and analysis81.8.4Research validity81.9LIMITATIONS91.10DELIMITATIONS91.11Definations of terms101.12FRAMEWORK OF REPORT101.13REFERENCES11

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1.1 INTRODUCTIONEkurhuleni Municipality had gone through electrical upgrades affecting most aspects of the power system in its distribution network for the past few years. One of municipalitys main substations is Palmridge substation which distributes 400 MW of power received from Eskom grid to hundreds of domestic and industrial consumers throughout Palmridge area. This research documents the innovative use of international standard communication with modern Ethernet network designs to protect, control, and monitor this 33 kV/6.6 kV substation. Substation automation in this area should be essential in order to maintain an efficient and reliable electrical infrastructure.

This report will focus on the analysis and implementation of the IEC61850 which will be performed in this substation to provide a general overview of its standard in terms of functionality and its scope. It will also discusses several key aspects of the electrical design, protection and control, communications network design, testing, and commissioning of an IEC 61850-based substation. The IEC61850 standard is developed to make this automation interoperable and cost-efficient. The IEC61850 standard has a number of benefits compared to previous automation standards which are often referred to as legacy standards and will addressed in this report (Sivertsen and Hammer, 2008, p. 6).

With rapid growth and understanding of the IEC 61850 communication protocol, the municipality considered and required several of the protocols and methods defined within the standard to be implemented in this substation for several reasons. The primary reason is to minimize the copper connections between the switch gear and the control house. This is effectively accomplished by using digital messaging over fiber cables to act as virtual wiring among networked intelligent electronic devices (IEDs) which in this case will be protection relays and Automatic Voltage Regulators (AVRs) (Tibbals and Dolezilek, 2010, p. 3).

1.2 research StatementThis project has two separate dimensions in that it consists of an analysis and an implementation of the IEC61850 in a substation. The analysis of the standard is necessary both in order to provide the desired overview of its content and scope, and also with regard to beginning to make an implementation of the standard. The overall task can be described as easing Ekurhulenis employment of the IEC61850 protocol by providing a useful overview of the contents of the standard and constructing a generic implementation of a suitable part of the standard that can be easily extended or modified according to the needs and wishes of the Municipality.Because of the comprehensive nature of the IEC61850 standard, a suitable demarcation is necessary to pinpoint the focus area of the software implementation of this project.This leads to a research statement: Analysis and implementation of IEC 61850 in a substation.1.3 research questionThe overall objective of the research is to find out how the IEC61850 protocol is being implemented and practiced in the electrical substation. In order to answer this question in detail the following sub- question will be used. Do the IEDs compatible and properly configured for IEC61850 on this substation? Is the IEC61850 protocol for the entire network in this substation properly implemented? Do the correct format of the GOOSE message generated and successfully transmitted over the network EIDs? Does the goose communication stacks applied to the IEDs meeting the behaviour requirements specified by the IEC 61850 standard?1.4 aim of researchThe aim of the research is to successfully apply the IEC61850 standard for communication and data transfer between the IEDs supporting the communication needs required by municipality for protection, monitoring, automation, metering and control. 1.5 value of researchThe benefit of this study includes the following: Simple substation structure: Ekurhuleni municipality will have no more interfacing problems. With IEC 61850, protocol diversity and integration problems are going to be eliminated. Everything should be simpler: from engineering to implementation, from operation to service. Time and costs on configuration, commissioning and maintenance should be saved with the application of IEC61850 in Palmridge substation. Reduction of costs: IEC 61850 replaces wiring between feeders, control switches, and signalling devices. More reliability: You only use one communication channel for all data in real time, synchronized via Ethernet. Reduced number of field terminations, associated wiring, labour, and maintenance due to the reuse of data detected by a single IED digitally communicated to integrated IEDs and other data clients. . Maximizing supervision should be achieved by replacing traditional unmonitorable copper terminations with monitored digital communications at the IED closest to the field data, which in turn detects and alarms communications problems immediately. Reduced quantity of IEDs due to the fact that newer multifunction IEDs replace multiple individual purpose IEDs and that integration of IED data eliminates several traditional stand-alone systems including those that perform SCADA, metering, sequence-of events recording, and digital fault recording.1.6 research objectiveThis study will seek to achieve the following objectives: To conduct research on the history of IEDs used in this substation and review of design theory for IED hardware and software applied. To conduct a study on the analysis of IEC 61850 modelling and implementation to all substation bays IEDs. To conduct a study on analysis of the frame format of the GOOSE message and its successful transmission over the network. To evaluate the Goose performance in order to confirm that the communication stack used meet the behaviour requirements specified by the IEC 61850 standard.1.7 literature review pertaining to research questionThe general title of the IEC61850 standard is Communication networks and systems in substations. The standard consists of the following parts: Palmridge substation IEC61850 layout Substation IEC61850 standard introduction and overview Glossary: Explains terms and abbreviations used throughout the standard General requirements: Specifies system requirements with emphasis on the quality requirements of the communication network. System and project management: Specifies system and project management with respect to the engineering process, life cycle of overall system and IEDs1, and the quality assurance. Communication requirements for function and device models: describes all required functions in order to identify communication requirements between technical services and the substation, and between IEDs within the substation. The goal is interoperability for all interactions. Substation automation system configuration description language: specifies the SCL file format for describing communication related IED configurations, IED parameters, communication system configurations, function structures, and the relations between them. Basic communication structure for substation and feeder equipment Principles and models: Introduces modelling methods, communication principles and information models used in IEC61850-7. Also, detailed requirements and explanations are given regarding the relation between IEC61850-7-x and the requirements from IEC51850-5. Abstract communication service interface (ACSI): Presents the ACSI providing abstract interfaces describing the communications between a client and a remote server, such as interfaces for data access and retrieval, device control, event reporting and logging. Common data classes: specifies common attribute types and common data classes related to substation applications. The common data classes specified, are for instance, classes for status information, measured information, controllable status information, controllable analogue set point information, status settings and analogue settings. Compatible logical node classes and data classes: specifies the compatible logical node names and data names for communication between IEDs.Specific communication service mapping (SCSM) Mapping to MMS3: specifies how time-critical and non-time-critical data may be exchanged through local area networks by mapping ACSI to MMS. Specific communication service mapping (SCSM) Serial un-directional multi-drop point to point link: specifies the specific communication service mappings for the communication between bay and process level and a mapping of the abstract service for the transmission of sampled values. These are specified on a serial unidirectional multi-drop point to point link. Mapping on based process: defines the SCSM for the transmission of sampled values according to the abstract specification. Conformance testing: specifies how a SAS4 should be tested to ensure conformance with the IEC61850 standard.1.8 RESEARCH METHODOLOGYA research methodology is the how of collecting data and the processing thereof within the framework of the research process (Brynard and Hanekom, 1997:27). This research targets the implementation of the IEC 61850 standard with the development of its oriented-object models transforming it into a concrete application protocol. The design, implementation, simulation and testing of various components will be carried out using appropriate software development and network design tools. IEC 61850 standard is to be examined in detail as well as identifying the most appropriate software development technique to achieve the successful implementation of the standard. The communication requirements set by the IEC 61850 standard will be investigated and the currently available communication architectures will be analysed in order to recognise their strengths and weaknesses. The topics that will be reviewed will includes A literature reviews History of IEDs and review of theory for IED hardware and software Analysis of the IEC61850 standard The IEC61850 Standard - Overview and Scope including modelling and implementation aspects GOOSE frame format analysis utilizing data network utilities Analysis of a test scenario for an aspect of cyber security Challenges Encountered Application of results Proposed improvements and ongoing work status Data Model Substation Configuration Description Abstract Communication Service Interface Information Models 1.8.1 Research ApproachThe research intended to be carried out will focus primarily on the application of IEC 61850 standard in a substation, but across all of its areas of application namely: Protection, Monitoring, Control, Instrumentation, Command and Supervision. In order to cover a wide and varied range of sources, the research will target academic papers, technical journals, articles from magazines, documents from conferences, as well as reports published by the main suppliers, and leader utilities in the sector. 1.8.2 How research instrument developed In this research the two main research instrument that will be used is equipment data downloading and the consultation with SEL relays suppliers. Consulting is one of the best methods of data and information gathering. In this research unstructured interview will be conducted with IEC61850 engineers from Schweitzer and different sectors IEC61850 specialists in South Africa. Downloading method will be done through data which will be configured and programmed to the equipment and IEDs installed in this substation (Palmridge).1.8.3 Data collection and analysisIn this research both the Secondary source and primary source will be used as the method for data collection and this will be done as follows;In primary data collection, data will be collected from IEC61850 engineers in the form of consultations. As a part of primary data collection unstructured interviews will also be conducted with protection engineers and IEC61850 specialists and gurus. The Secondary data collection will be done by using engineering books, technical manuals, articles and IED downloads in order to find out the outcome of these researches. The data that will be collected using this different method will be analysed and presented in a form of waveforms, graphs, drawings, circuit diagrams and conclusion will be developed from this analysed data.1.8.4 Research validityValidity refers to the accuracy or truthfulness of a measurement. The researcher will make sure that this research is being done in an ethical manner and credit and acknowledgement will be given were it is due. All assessments of validity are subjective opinions based on the judgment of the researcher this research is validity and is a true reflection of what the research will find and use in completing this report, some of the information will be an already proven ways to analyse data.1.9 LIMITATIONSThe research project is limited to the analysis and implementation of an IEC 61850 protocol on Schweinzer relays or the SEL IED and its compatible products.The following tasks form part of the project: Analysis of methods for IEC 61580 standard implementation; Software modelling as well as software implementation for the intelligent electronic devices. Testing of the IEC 61850 standard on the intelligent electronic devices employed in this substation.1.10 DELIMITATIONSThis research will focus more on the analysis and implementation of IEC 61850 communication protocol applied to compatible equipment in the electrical substation.

1.11 Definations of terms Generic Object Oriented Substation Event: High performance multi-cast messaging service for inter-IED communications, and is used for fast transmission of substation event. Intelligent Electronic Device: Device incorporating one or more processors, with the capability to receive or send data/control from, or to, an external source. Device capable of executing the behaviour of one or more specified logical nodes in a particular context and delimited by its interfaces. Substation Configuration description Language: Description language for communication in electrical substations related to the IEDs. Substation: A node in an electrical power network where lines and cables are connected for transmission and distribution of electric power.1.12 FRAMEWORK OF REPORTThe research consists of six chapters detailing the background information, problem definition, developed methods, software application, integration techniques applied, challenges encountered and results of the research project.Chapter 1 presents an overview of the research project highlighting the research aims, the research limitations and delimitation, the research methodologies, research aims and objectives, value of research and a description of the originality of the research.Chapter 2 presents the literature search and analysis including a detailed literature review.Chapter 3 provides detailed information about the target hardware platform that is used to implement the IEC 61850 protocol.Chapter 4 provides detailed information about information model, information exchange model, the device model and the substation module including an overview of the target hardware and software platform that is used to implement this protocol standard to the IEDs. This chapter also describes the modelling of the selected case study based on the IEC61850 standard.Chapter 5 this chapter presents the testing procedure to verify the correct implementation of the IEC61850 standard. All results of this study are described and analysed.Chapter 6 provides the conclusion to this research project. The benefits that this research project offers are described and future research prospects for expansion of this project and other related relevant projects in this field of study are identified. Chapter 1 - Introduction Chapter 2 Analysis and Literature review Chapter 3 - Research Design Chapter 4 - Implementation Chapter 5 - Testing and Results analysis Chapter 6 Conclusions and recommendations

2LITERATURE REVIEW 2.1Introduction The purpose of this chapter is to provide the necessary background required to understand the concepts that relate to power system communications, recent standardisation developments and the use of protocols with respect to the IEC 61850 applied at Palmridge substation.This chapter is structured in the following fashion starting with an IEC 61850 philosophy and objectives in Section 2.2, Intelligent Electronic Devices in Section 2.3. Analysis of the IEC61850 standard in Section 2.4 and the Conclusion on Section 2.5 2.2 IEC 61850 philosophy and objectivesAccording to the Digital Bond (2010) website: The IEC 61850 standard was designed to provide a robust architecture network, common communication protocol suite, common data format and naming convention, interoperability, fast communications among field devices, guaranteed data delivery within a pre-defined time, configuration support, and defines complete testing requirements for substation equipment.It is a standard that encompasses multiple disciplines, and that makes use of existing standards as well as commonly accepted communication principles and accepted protection methods. The IEC 61850 standard is the primary source of information, and has been used as a guideline for implementation and adaptation.To summarize, the IEC 61850 is driven by three main philosophical concepts which are: Virtualisation: Development of a method to create a generic substation model of all relevant components and functions. A method which allows flexibility for future communication needs by incorporating service and mapping mechanisms which will accommodate this. Exchange of information through XML files for device capability and system architecture needs for engineering the Substation AutomationThe points listed above can be viewed as the most pertinent aspects for different institutional bodies or individuals interested in the IEC 61850 standard.The objectives of the IEC 61850 standard can be stated as follows: Interoperability between all communicating equipment; Free Configuration of the system; Long Term Stability with respect to technological evolution.2.3 Intelligent Electronic DevicesMost of Ekurhulenis electricity substations consists of digital relays and other Intelligent Electronic Devices (IEDs) that record and store a variety of data in relation to their control interface, internal operation and about the power system they monitor, control and protect. Instrumentation & Control (I&C) devices, which are built using microprocessors, are commonly referred to as IEDs. Microprocessors are single-chip computers that can process data, accept commands and communicate information.Ekurhuleni municipality is using digital relays are in replacing the aging electromechanical and solid-state electronic component-type relays and relay systems.

Figure 2.1 Digital relay with target interfacesAbove figure shows a typical connection diagram of digital relay with its target interfaces. Digital relays popularity comes from their low price, reliability, functionality and flexibility. However, the most important feature that separates a digital relay from previous devices such as electro mechanical relay is its capability of collecting and reacting to data and then using this data to create information. Such information includes: Protection Data: Fault location and fault type, Metering Data: Pre-fault, fault and post-fault currents and voltages, Breaker and relay operation data, and Diagnostic and historical data.IEDs installed are running automatic processes while communications are handled through a serial port similar to the communication ports on a computer. Some examples of IEDs used in this power network are: Instrument transformers relays such as voltage regulators, Remote Terminal Units (RTUs), and Digital fault recorders.2.4 Analysis of the IEC61850 standardThe purpose of this section is to provide insight and overview of how the standard is structured and how it is used in this particular substation. First, basic concepts of the standard are explained and then a brief overview is given of the contents of the standard. Afterwards, the different parts of the standard are inspected individually and analysed in more detail.2.4.1 Basic Concepts of IEC61850A substation can be defined as a node in an electrical power network where lines and cables are connected for transmission and distribution of electric power. Palmridge substation has the capability of transforming electricity, from high to low voltage for distribution by a low-voltage network. This substation therefore has two transformers and it has many other functions as well, such as switching, breaking and protection capabilities. Substation automation system (SAS) utilised in this substation is a computer system which allows an administrator to communicate with the substation over a computer network such as the internet. When developing this system it was necessary to create a model of a general substation with all of its components and functions. Then it is necessary to stipulate the exact form of communication that is allowed and supported by the system. This describes exactly the challenges addressed by the IEC61850 standard.A substation can often comprise a number of IEDs. When an IED is added, the extension must be reflected in the particular instance of the data model modelling the substation. The IEC61850 standard allows for configuration and modifications to a SAS, through the use of SCL which is defined in IEC61850-6.

2.4.2 The IEC61850 Standard - Overview and ScopeThe general title of the IEC61850 standard is Communication networks and systems in substations. The standard consists of the following parts: IEC61850-1 Introduction and overview IEC61850-2 Glossary explains terms and abbrevations used throughout the standard IEC61850-3 General requirement specifies system requirements with emphasis on the quality requirements of the communication network. IEC61850-4 System and project management specifies system and project management with respect to the engineering process, life cycle of overall system and IEDs1, and the quality assurance. IEC61850-5 Communication requirements for function and device models describes all required functions in order to identify communication requirements between technical services and the substation, and between IEDs within the substation. The goal is interoperability for all interactions. IEC61850-6 Substation automation system configuration description language specifies the SCL file format for describing communication related IED configurations, IED parameters, communication system configurations, function structures, and the relations between them. The purpose is to exchange IED capability description, and SA2 system descriptions between IED engineering tools and different system engineering tools. IEC61850-7 Basic communication structure for substation and feeder equipment IEC61850-7-1 Principles and models Introduces modelling methods, communication principles and information models used in IEC61850-7. Also, detailed requirements and explanations are given regarding the relation between IEC61850-7-x and the requirements from IEC51850-5. IEC61850-7-2 Abstract communication service interface (ACSI) presents the ACSI providing abstract interfaces describing the communications between a client and a remote server, such as interfaces for data access and retrieval, device control, event reporting and logging. IEC61850-7-3 Common data classes specifies common attribute types and common data classes related to substation applications. The common data classes specified, are for instance, classes for status information, measured information, controllable status information, controllable analogue set point information, status settings and analogue settings. IEC61850-7-4 Compatible logical node classes and data classes specifies the compatible logical node names and data names for communication between IEDs. IEC61850-8 Specific communication service mapping (SCSM) IEC61850-8-1 Mapping to MMS3 (ISO/IEC 9506 Part 1 and Part 2) specifies how time-critical and non-time-critical data may be exchanged through local area networks by mapping ACSI to MMS. IEC61850-9 Specific communication service mapping (SCSM) IEC61850-9-1 Serial un-directional multi-drop point to point link specifies the specific communication service mappings for the communication between bay and process level and a mapping of the abstract service for the transmission of sampled values. These are specified on a serial unidirectional multi drop point to point link. IEC61850-9-2 Mapping on an IEEE 802.3 based process defines the SCSM for the transmission of sampled values according to the abstract specification in IEC618507-2. IEC61850-10 Conformance testing specifies how a SAS4 should be tested to ensure conformance with the IEC61850 standard.

2.4.3 Data ModelAs was illustrated in figure 2.1, logical nodes are key objects in the IEC61850 data model. The data model is hierarchical and logical nodes are the essential elements of this model. A logical node represents a particular function within a device and can be defined as the smallest part of a function that exchanges data. The IEC61850 standard defines 91 different logical node classes which are grouped together into 13 logical node groups according to their functionality. In an instance of the data model, some of the logical node instances may be grouped together into a bay which is defined as closely connected subparts of the substation with some common functionality. A bay is thus a logical grouping, not necessarily a physical device. In the hierarchical data model, it can be represented by a logical device.In a substation there can be one or more physical devices. A physical device has one or more servers and a server is the topmost object in the hierarchical data model. A logical device is a more fine-grained grouping of functionality related to a particular physical device. The logical device is contained in a server. Thus, one server may have more than one logical device and a logical device may contain several logical nodes.Hubert Kirrmann of ABB Research Center states that: Although IEC 61850 is defined as a communication structure for substation and feeder equipment its main contribution is the definition of an object model for all substation objects. It is clear that since the standard has interoperability as a goal, its data model is of essential importance, and therefore it is an advantage that all functions can be modelled precisely and by predefined objects.An important aspect of the object model is the fact that users are allowed to name substation components in a meaningful way. This is a consequence of the object oriented approach used for developing the standard.The standard defines an object reference to differentiate between a reference to an object and the object name. The object reference is important in terms of implementation and is based on the data model in a straight forward manner. The object reference is comprised of the objects ordered hierarchically according to the data model and with dots between them. The general format is: LD/LN.Data.DataAttribute

2.4.4 Data communication philosophy- Definition of a GOOSE messageThe Generic Object Oriented Substation Event (GOOSE) is provided to report any change of state of an IED to other peer devices (IEC61850-2_p16).Figure 2.2 below, shows the mapping profile of the IEC 61850 protocol suite. It is acknowledged that communication protocols such as GOOSE and Sampled Value messages are mapped over two layers of the OSI model which are: the Physical layer (layer 1) and the Data-link Layer (layer2).

Figure 2.2: Protocol mappings profile

A GOOSE message allows for high speed trip signals to be issued with a maximum probability of delivery within a specific time range.

Table 2.1 gives information about the time requirements for different applications used within the substation.1AFast Messages (Trip)P1 and P2/P310 ms and 3 ms

1BFast Messages (other) P1 and P2/P3100 ms and less than 20 ms

2Medium Speed100 ms

3Low Speed500 ms

4Raw DataP1 and P2/P310 ms and 3 ms

5File TransferAbove 1000 ms

6Time SynchronisationAccuracy

Table 2.1: IEC 61850 message types and performances.2.4.5 Substation Configuration Description LanguageA substation may be altered in structure for instance if one or more IEDs are added.Such additions can be defined by use of an SCL file. The SCL language allows for configuration of a substation both before employment but also as further equipment is added to the substation. SCL is short for Substation automation system Configuration description Language.The SCL file format is used for describing communication related IED configurations, IED parameters, communication system configurations, function structures, and the relations between them. The purpose is to exchange IED capability description, and substation automation system descriptions between IED engineering tools and different system engineering tools.ExtensionNameDescription

.icdIED Capability DescriptionDefines complete capability of an IED. Contains single IED description, optional communication system description and optional substation description.

.ssdSystem Specification DescriptionComplete specification of SAS excluding IED descriptions

.scdSubstation Configuration DescriptionComplete specification of SAS excluding IED descriptions

.cidConfigured IED DescriptionMakes communication possible betweenan IED and an IED configuration tool.

Table 2.2 SCL file types. The SCL language is made up of four file types, each with a specific purpose. The types are shown in table 2.1.1.

Any SCL file is structured with XML format and is made up of some of the following five parts, depending upon its purpose:1. Header2. Substation description3. IED description4. Communication system description5. Data type templates

2.5 ConclusionThe IEC 61850 standard covers not only communication, but also qualitative properties of engineering tools, measures for quality management and configuration management (Ozansoy, 2006). More importantly, the IEC 61850 standard specifies a common reference model to exchange data configuration of Intelligent Electronics Devices (IEDs). This exchange is made possible by the use of the Substation Configuration Language (SCL) files that allow for the transfer of IED configuration from one software engineering tool to another to integrate an IED within the Substation Automation System (SAS) (Martin and Nguyen, 2004).The benefits that are derived from the IEC 61850 standard from this review are: Introduction of a standardized substation architecture and communication protocol in terms of addressability via a communication bus (reducing cabling cost). Interoperability of equipment provided by different vendors. Easy maintenance and reconfiguration of the overall architecture of the substation and/or functions perform by all associated equipment. Capacity added within the substation to detect faults or inactive IEDs within its own architecture. This prevents the substation from mal-operation due to faulty IEDS left unattended within the substation architecture, under the assumption that they are working properly.3. IEC 61850 Design3.1 Substation Design & LayoutPalm ridge substation incorporates the IEC61850 station bus standard utilizing Logical Nodes and the GOOSE messaging for all protection & control for 11 kV incomer and breakers, transformer primary and back up set protection, data acquisition of the transformer, transformer on load tap changer control, breaker control, supervisory control & data acquisition (SCADA), operational interface panels (OIP), digital fault recorder interface and miscellaneous station data.The IEC61850 IEDs used in the final design of the Palm ridge Substation are shown in Figure 3.2. IEDs on the 11 and 6.6 kV make up the IEC61850 implementation of this project.

Figure 3.2 Line protection relays LA99A, LB99A, 9A99A, 9299A &9B99A are GE-Multilin D60 relays (GE-D60). Breaker control devices LA52BCA, LA52BCB, L252BCA,L252BCB, LB52BCA, LB52BCB, 9152BCA, 9152BCB,C1652BCA, C1652BCB, 9A52BCA, 9A52BCB, C2652BCA &C2652BCB are Siemens 7SJ64 relays (SIEMENS-7SJ64). Transformer protection consists of two SEL-387A relays for differential protection and two SEL 751A relays back-up overcurrent and earth fault relays for two of the transformers. OLTC control and transformer monitoring are the two REG-DA relays for two transformers. 30SHA - Set A substation alarms and auxiliary controlLogic is GE-Multilin C30 relay (GE-C30). 30SHB - Set B substation alarms and auxiliary controlLogic & IEC61850 interface to set B transformer protectionis ABB REC 670 relay (ABB-REC 670).

3.2 Transformer ProtectionTwo complete, comprehensive and independent transformer protection packages or schemes are implemented. The transformer bank is a delta-star 11/6.6 kV with a 40 MVA capacity through the use of two three-phase transformer. Primary protection (SEL 387A) provides transformer differential protection, over current protection, transformer sudden pressure protection, OLTC sudden pressure protection and restricted ground fault protection for both neutral CTs. Every transformer status and alarms, such as fan status, liquid levels, etc. are collected by the 30TA, 30TB, 30TC & 30TS devices (GE-C30), which are located in cabinets mounted on each of the two three-phase 11/6.6 kV transformers. Analog and digital data from 30TA, 30TB, 30TC & 30TS IEDs are available in IEC61850 format to OIP-A, OIP-B and SCADA. All trip cut-out switches and lockout relays (LORs) for transformer protection are considered virtual and resident within the transformer main protection IED logic. These virtual switches can be manipulated from OIP-A, OIP-B, SCADA or main protection front panel pushbuttons. LEDs and virtual LEDs on the OIP provide various system conditions relating to a complete transformer bank protection scheme. The 87B device is a non-IEC61850 IED using a conventional LOR (lock out relay) and hard-wire trips.Typical transformer fault scenario Condition: An internal fault to the transformer has occurred. What happens? A set - The 87A IED determines a fault condition. Depending on the virtual 29DA trip cut-out switch (in the ON position), the 87A IED will issue a GOOSE message (bank differential set A operated). This GOOSE message will be used by each of the eight 52BC IEDs (SIEMENS-7SJ64) LA52BCA, LA52BCB, LB52BCA, LB52BCB, 9152BCA, 9152BCB, C1652BCA, C1652BCB) to trip & lockout individual breakers & open corresponding isolating switches. The same GOOSE message will also initiate, LB99A, 9299A, 9A99A. When a transformer fault condition is detected the 87A will also simultaneously close its output contacts (for risk management purposes), which are directly connected to trip the four breakers involved in the transformer differential zone of coverage. B set - The 87B relay determines fault condition and closes its trip contact on the I/O board. This contact is in series with the 29DB trip cut-out switch (in the ON position) which energizes the 94B LOR. The 94B device has contacts wired directly to trip the four breakers involved in the transformer differential zone of coverage. The 94B also has a contact wired into the 30SHB device to indicate the transformer fault condition to other IEC61850 IEDs, SCADA & local OIP-B. The 30SHB will then issue a GOOSE message to initiate breaker failure within B set line/breaker protection IEDs (ABB-REL 670) LA99B, LB99B, 9299B, 9A99B for a transformer fault condition.

3.3 Transformer OLTC ControlThe substation transformers have On Load Tap Changer (OLTC) for each of the two three-phase 11/6.6 kV transformers. Each OLTC has controls enabling SCADA or OIP (via 30TA, 30TB, 30TC & 30TS IEDs) to raise or lower its tap position.These controls are in addition to the individual transformer OLTC controls provided by the manufacturer.The position of the virtual switch supervises the raise & lower commands sent to various OLTC control units. That is, the OIP or SCADA will have the option to select which tap changer is to accept the raise/lower singular command submitted by the OIP-A, OIP-B and SCADA

3.4 Breaker ControlBreaker control devices LA52BCA, LA52BCB, L252BCA, L252BCB, LB52BCA, LB52BCB, 9152BCA, 9152BCB, C1652BCA, C1652BCB, 9A52BCA, 9A52BCB, C2652BCA & C2652BCB are Siemens 7SJ64 relays (see Figure 4).The substation contains redundant breaker control devices. The idea behind dual breaker control IEDs is to meet the same redundancy requirement as for line protection. The IEDs as shown in Figure 2 have generic names 52BCA and 52BCB. This defines a breaker (52) IED providing breaker control (BC) and which set (A or B) it corresponds. These devices are mounted inside an enclosure located on the breaker mechanism leg.This enclosure will be referred to as an IED auxiliary cabinet. The individual breakers mechanism or control cabinet will be referred to as the main cabinet. Each breaker control 52BC IED will listen for a GOOSE message requesting their breaker or MOD to be operated.Along with the breaker control IEDs, other components and devices will also be located in the IED auxiliary cabinet. They include a temperature thermostat, auxiliary cabinet heater, condensation monitor and an on-line breaker monitor.

3.5 Device specifications3.5.1 SEL-387A Relay Specification

The microprocessor-based relay shall provide a combination of functions including protection, monitoring, control, and automation. Relay self-checking functions shall be included. Specific requirements are listed below:Percentage Differential Protection: The relay shall incorporate restrained differential protection for two windings with fixed or variable percentage, using one or two settable slopes with adjustable intersection point and minimum pickup values.Harmonic and DC Elements: The relay shall incorporate second-, fourth-, and fifth-harmonic and dc elements, with the choice of either harmonic blocking or harmonic restraint to prevent restrained differential element operation during inrush or over-excitation conditions; an independent fifth-harmonic alarm element shall be included to warn of an over-excitation condition.Unrestrained Differential Protection: The relay shall include unrestrained differential protection to produce rapid tripping for severe internal faults.Overcurrent Fault Protection: The relay shall incorporate two groups of three-phase current inputs and three sets of neutral overcurrent elements that can be independently enabled for overcurrent protection. Eleven overcurrent elements per winding shall be included to provide phase, negative-sequence, and residual protection. CT Phase Angle Compensation: The relay shall incorporate full round-the-clock current compensation, in 30-degree increments, to accommodate virtually any type of transformer and CT winding connection.Status and Trip Target LEDs: The relay shall include 16 status and trip target LEDs.Restricted Earth Fault Protection: The relay shall incorporate two sets of restricted earth fault (REF) protection for the detection of ground faults in wye-connected windings.Communication: The relay shall include three EIA-232 and one EIA-485 serial ports to provide flexible communication to external computers and control systems. The relay shall operate at a speed of 30019200 baud. Three-level password protection shall be included to provide remote security communication.Distributed Network Protocol (DNP): The relay shall incorporate certified DNP3 Level 2 Slave protocol communications capability. The DNP capability shall include automatic dial-out for settings-based DNP events and virtual terminal support with full ASCII capability.Relay Logic: The relay shall include programmable logic functions for a wide range of user-configurable protection, monitoring, and control schemes.Auxiliary Inputs/Outputs: The relay shall include fully programmable opt isolated inputs and output contacts.Trip and Close Variables: The relay shall include three trip variables and two close variables to permit separate control of up to two breakers and a separate lockout device.Setting Groups: The relay shall include six selectable setting groups to permit easier adaptation to changes in application.Metering: The relay shall include metering capabilities for real-time phase and differential quantities, as well as phase demand and peak demand current values. Harmonic content from the fundamental to the 15th harmonic for all phase currents shall also be included.Circuit Breaker Monitor: The relay shall include two breaker wear monitors with user-definable wear curves, operation counters, and accumulated interrupted currents per phase.Substation Battery Monitor: The relay shall measure and report the substation battery voltage presented to the relay power supply terminals. Four selectable threshold parameters shall be provided for alarm and control purposes.Through-Fault Event Monitor: The relay shall provide for the capability of reporting fault current level, duration, and date/time for overcurrent events through the differential protection zone. A settable I2t alarm indicates an excess of accumulated through-fault energy.Temperature Metering: The relay shall include temperature metering for up to 24 external RTDs. RTD inputs to the relay shall be via serial communications ports.Event Reporting and Sequential Events Recorder (SER): The relay shall be capable of automatically recording disturbance events of 15, 30, or 60 cycles with settable pre-fault duration and user-defined triggering. Events shall be stored in non-volatile memory. The relay shall include an SER that stores the latest 512 entries. Automation. The relay shall include 16 local control elements, 16 remote control logic points, 16 latching logic points, and 16 display messages in conjunction with a local display panel included in the relay. The relay shall have the capability to display custom messages.Internal Real-Time Clock. The relay shall include a real-time clock, with battery backup, synchronizable to demodulated IRIG-B input, to provide accurate time stamps for event records.Low-Level Testing. The relay shall include a low-level test interface to permit relay testing with low-energy test equipment.

1.13 REFERENCES

Hammer, Sivertsen. (2008): Analysis and implementation of the IEC 61850 standardD. Dolezilek, IEC 61850: What You Need to Know about Functionality and Practical Implementation, presented at the Western Power Delivery Automation Conference, Spokane, WA, 2005KOSTIC, T., AND FREI, C. (2007): Modelling and using IEC 61850-7-2 (ACSI) as an API. KOSTIC, T., PREISS, O., and FREI, C. (2005 Understanding and using the IEC 61850: a case for meta-modelling. Erasmus P1 and van Waveren2. C.C South African Journal of Industrial Engineering November 2009 Vol 20(2): 93-105 Kenneth H.V Rose (2005): Project Quality Management. Ross PublishingLeedy PD & Ormrod JE. 2005. Practical Research, Planning and Design. New Jersey: Pearson-Prentice Hall.