ENGINEERING AND CONFIGURATION OF SUBSTATION COMMUNICATION SYSTEM USING IEC 61850 SUBSTATION

CONFIGURATION LANGUAGE: A TNB EXPERIENCE

Mohd Noorfazly Noran

Mohd Iqbal Ridwan

Muzlifah Hanim Zarmani

Hairol Rizat Sabtu

Normi Salwana Miswan

Muhamad Shahmi Shokri

TNB Research Sdn Bhd

Kuala Lumpur, noorfazly.noran@tnbr.com.my

Aminuddin Musa

Tenaga Nasional Berhad

Kuala Lumpur, aminuddinmu@tnb.com.my

ABSTRACT

IEC 61850 Standard (Communication Networks and Systems in Substations) is an open standard for communication in substation and has defined standardised methodology to design information exchange between substation devices. This methodology is called substation configuration language which is defined in part 6 of the standard. This method allows seamless information exchange between devices from various makes which comply with IEC 61850 Standard. Realizing this benefit, TNB has utilized HELINKS STS which is a third party substation engineering tool to design and configure the substation communication system for TNB IEC 61850 based substation. The objectives of this paper are to demonstrate the IEC 61850 top-down engineering approach for creating the system specification description (SSD) file and system configuration description (SCD) file and the IEC 61850 engineering process of SVSL by using HELINKS STS.. KEYWORDS: IEC 61850, HELINKS STS, System Specification Description (SSD), System Configuration Description (SCD), IED Configuration Description (ICD, Logical Nodes (LNs)) 1. Introduction

IEC 61850 is the standard for communications networks and systems within electrical substations. It defines the substation information model and the information exchange mechanism [1]. It is a common standard for substation communication which allows the communication between Intelligent Electronic Devices (IED) from different vendors [2]. Part 6 of the standard has defined the lingua franca of the substation communication called substation configuration description language (SCL) for configuring substation secondary devices and communication [3]. The SCL is based on extended markup language (XML) format and has several types of description file such as System Specification Description (SSD) file, IED Configuration Description (ICD) file, System Configuration Description (SCD) file and Configured IED Description (CID) [3-4].

SSD file is a formal description of the substation single line diagram together with the functions to be performed at the primary equipment, in terms of logical nodes. ICD file is the capabilities of an IED type in terms of communication functions and of the data model application functions. SCD file is a description of the communication and function configuration of a substation automation system and its relation the switch yard. CID file is a subset of SCD file used for the IED configuration and all its needed data coming from the rest of the system [4].

Generally, these SCL description files are used to define the information of the substation single line diagram, substation secondary functions and the substation communication architecture. SCL is intended to enabling the interoperable between different engineering tools from different manufacturers with the integration and configuration of description files for IEC 61850 engineering process [3]. In the future, SCL as a core language format for the engineering process will provide flexibility in terms of configuring and designing the substation secondary system with multi-vendors IED. It also will simplify the process of substation communication configuration and protection and control scheme modification work in substation expansion project. 2. IEC 61850 Engineering Process for TNB Substation using HELINKS STS

The SCL and the engineering process are described in IEC 61850-6 standard. The IEC 61850 engineering processes, the relevant generated SCL files, and the relationship among the engineering tools and the SCL files are summarized in Figure 5.

Figure 1 IEC 61850 Engineering Process

The specified substation topology such as single line diagram, substation equipment interfaces and functions in terms of Logical Nodes (LNs), relationship among substation equipment and functions, and data signals in the LNs are translated into IEC 61850 SSD file. This SSD file is generated or created using System Specification Tool. The IED capability templates of the available Logical Device, available functions in the form of LNs, available communication Services, Data Sets, Control Blocks (e.g. Reporting or GOOSE) and Data Object/Attributes can be formally described by IED ICD file which can be generated or downloaded from IEDs by the manufacturer specific IED Configuration Tool.

Using the System Configuration Tool, the SSD file and the ICD files from multivendor IEDs are imported and configured by the engineering tool. The System Configuration Tool specifies the relationships between the substation functions defined in the system specifications and the IEDs to be installed. The Function Naming addresses in the SSD and the Product Naming addresses in ICD files from all implemented IEDs are linked and configured to generate the SCD file. The engineering tool compares the IED ICD files with the SSD file to verify whether the IEDs capabilities

In order to materialize this process, TNB has identified HELINKS STS as a third party configuration tool for configuring the Substation Configuration Language (SCL) file of the substation. HELINKS STS software comprises two tools, System Specification Tool and System Integration Tool for configuring the Substation Specification Description (SSD) file and System Configuration Description (SCD) file as shown in Figure 3.

Figure 2 IEC 61850 Engineering Tool 3. SSD File Configuration

The substation primary and secondary system can be specified by means of a System Specification Description (SSD) file. This file can be produced using HELINKS STS System Specification Tool. The SSD file describes the single line diagram of the substation, associated with the primary equipments functions represented by specific LNs. The SSD file contains the following IEC 61850 specification information; primary equipment (single line), electrical system topology (optionally including x-y coordinates for single line), electrical connections and Automation and protection functions related to primary equipment

The substation primary equipment can be modelled by drawing the substation single line diagram (SLD), as shown in Figure 3, in the HELINKS STS Single Line Diagram Editor Figure 4. The drawing of the SLD of substation is in hierarchy structure, i.e. in the following order Substation, Voltage Level, Bays, Equipments and Connectivity Node.

Figure 3 Typical TNB Substation SLD

Figure 4 Drawing of SLD in HELINKS STS Single Line Diagram Editor By default, HELINKS STS automatically map the specific LNs such as XCBR, XSWI, CSWI and CILO to the corresponding primary equipments. The LNs that associated with the primary equipments can be viewed in HELINKS STS Function Specification Editor as shown in Figure 5. All of the LNs of the primary equipments are mapped as an information model which will be used for the SSD file configuration.

Figure 5 LNs of the Primary Equipments

The secondary system functions, such as protection, automation, control, measuring, and ancillary signals for TNB substation can also be mapped or allocated in HELINKS STS. HELINKS has also created utility customized interface file, i.e. PIO file, which is embedded inside the engineering tool that allows user such as TNB to directly import the required function and signal lists in Excel format (see Figure 6) into the HELINKS STS Single Line Editor.

Figure 6 TNB IEC 61850 Function List

TNB standard function and signal list format is based on the model structure of HELINKS STS; i.e. Substation, Voltage Level, Bay, IED, TNB Code, Signal Name, Prefix, Logical Node, Instant and Data Attribute. This list is compiled based on the type of circuits or bays that are available in TNB substation such as Overhead Line, Transformer, Bus Coupler and Bus Section. The functions that have been listed were based on the TNB Transmission SCADA point list and Teleprotection signal list.

LN is an object-oriented data model that groups all of data with a common function. All related data attributes are contained and defined in LNs [5]. There are several types of LNs that represent the substation functions such as protection, metering, recording supervision, controlling etc. The LNs associated with specific data attribute which will be used as an information model that can be linked with IEC 61850 communication services.

TNB has defined the suitable LNs for each signal with predefine prefix and LN instant associated with data attribute of each LNs. For the overhead line protection IED with integrated functions such as current differential, distance and overcurrent, these functions are represented by LNs PDIF, PDIS and PTOC respectively. TNB has also standardized the naming convention format for the IED name based on the concatenation of the bay name and IED function. For example, for IED name E01F11LP1, the term E01 represents the bay name and F11LP1 represents the integrated multi function line protection IED or relay. All of these are arranged per columns and the translation will be made by HELINKS STS which will transform it into predefined Intelligent Electronic Device (IED), Function Box and the required Logical Nodes in the Function Specification Editor as graphically shown in Figure 7.

Figure 7 Model of virtual IED and associated LNs

In the HELINKS STS Function Specification Editor, the Logical Nodes with common

function are grouped together in the Function Box which is linked to the predefined IED (virtual IED) for ICD file integration. The virtual IED is modeled in HELINKS as a platform for mapping the IED Configuration Description (ICD) file during IED implementation. The grey box in Figure 8 represents the virtual IED with several Function Boxes. The TNB function and

signal lists will be used not only for the SSD file generation but also as a part of TNB substation signal specifications or information checklist for the IED manufacturers to comply with. By directly importing the lists into HELINKS STS for automatic functional mapping, TNB will have the flexibility during engineering process for future reuse in new substation project.

Figure 8 Predefine IED with Assigned LNs In the SSD file, all of the substation bays have been mapped with specific Logical Nodes according to the type of bays. Figure 9 shows the SSD file as viewed in HELINKS STS SCL XML Editor.

Figure 9 SSD File in XML View 4. SCD File Configuration

The system configurations and integrations can be done by using HELINKS System Integration Tool. In this tool, the SSD file will be mapped with the ICD file for Substation Configuration Description (SCD) file configuration. SCD file is a file that describes the

communication and function configuration of a SAS. This file will be utilized by the manufacturer’s proprietary IED configurator tool for the actual IED configuration process.

In HELINKS STS, the SCD file configuration process start with importing the ICD files into HELINKS System Diagram for IED communication configuration. The System Diagram Editor is a graphical editor to represent communication sub networks according to the IEC 61850 object model (see Figure 10). Based on the communication structure in the SCD file, the configuration of network of the substation is started by adding a Sub Network in System Diagram Editor. HELINKS STS creates a copy of the ICD file where the IED Name is changed from “Template” to the user defined unique name (e.g. E01F11LP1). The IP address of the IED can be configured by using IEC 61850 connection in System Diagram palette. This process will built the communication part of the substation in SCD file with the Sub network name, IED name and IP address of devices will be updated based on the configuration in the System Diagram Editor as shown in Figure 11.

Figure 10 System Diagram Editor

Figure 11 Subnetwork of the System Diagram Editor

After configure the SCD communication section, the ICD files can be mapped in their counterpart bays for LNs mapping. This process can be done by mapping the IED from System Diagram with the virtual IED in Function Specification Editor for IED implementation as shown in Figure 12.

Figure 12 Implementation of IED to Function Specification Editor

The LNs of the specification can be mapped with the LNs of the implemented IEDs (ICD File). All of the mapped LNs can be used to create the dataset for IEC 61850 communication services which are Manufacturing Message Specification (MMS) report (buffered and unbuffered) and Generic Object Oriented Substation Event (GOOSE) messages. It also can be linked with the TNB substation clients such as SCADA, Station Level Operator Interface (SLOI) system and Engineering Workstation (EWS) system. For GOOSE message configuration, HELINKS STS provides a graphical user interface platform. The Application box as shown in Figure 14 is the place for the GOOSE message configuration. It can be created at the Single Line Diagram editor by selecting the Application tool from the palette. The APPID of the GOOSE message and the name of application (GoID) can be filled at the Property Tab. The AppID attribute will be used to group all GOOSE messages for this application.

Figure 13 GOOSE Application Editor 5. Discussion and Conclusion

Based on the top down approach for TNB IEC 61850 engineering process, some limitations of this way are discovered as follows: • Certain ICD files do not support the LNs being specified by TNB IEC 61850 function list. • Application Modeling is not really independent of the IEDs. Different philosophies inside

the IEDs require different application modeling with different signals. This is limiting the device independent application engineering.

• The communication configuration capabilities of IEDs are very different. E.g. Dataset either for report or GOOSE of certain IED are fix and not configurable

• Tool interoperability needs to be improved. Third party tools as well as vendor tools need to meet IEC61850 engineering process compliance as described in part 6.

As a conclusion, the IEC 61850 top down engineering process is a utility driven

engineering work that can help TNB to optimize the future IEC 61850 based substation engineering design. It also can standardize the implementation of IEC 61850 engineering work for TNB substation and will make the IEC 61850 engineering process in utility driven mode. 6. References: [1] T.S. Sidhu and Pradeep K Gangadharan (2005) Control and Automation of Power System Substation using IEC61850 Communication. Proceedings of the 2005 IEEE Conference on Control Applications, Toronto, Canada, August 28-31. [2] WANG HaiZhu, CAI ZeXiang, SU ZhongYang, ZHU ZhiHan (2011) The Analysis of Relay Protection Communication Mechanism Based on IEC61850 2011 The International Conference on Advanced Power System Automation and Protection

[3] Yong, H.K, Jeon, Y.H, You, J.L, Yong, H.A, and In, J.S (2011) Development of IEC 61850 Based Substation Engineering Tools with IEC 61850 Schema Library. 2011 Smart Grid and Renewable Energy, May 30. [4] IEC Std. 61850 - Part 6: Configuration description language for communication in electrical substations related to IED [5] Yashwant, K (2011) Modeling an IEC61850 Based Substation Automation System 2011 India Conference (INDICON), Annual IEEE 16-18 December.