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Sunday, 10 November 2013

IEC61850 Leading The Tendency of Substation Communication

IEC61850-The Future Protocol of Power Automation

The current in the power system, more and more high to the requirement of substation automation, for the convenience of all sorts of IED in substation management as well as the interconnection between equipment, you need to implement a common communication way.

Introduction of IEC61850 put forward a kind of public communication standards, a series of standardized, through to the equipment to form a standard output, to realize the seamless connection of the system. [1] IEC61850 standard is based on the general network communication platform of the substation automation system is the international standard, it is by the international electrotechnical commission 57 technical committee (IECTC57) three working groups of 10 final three (WG10/11/12) is responsible for.

This standard reference and absorbing the existing many related standard, which mainly include: IEC870-5-101 telecontrol communication protocol standards; IEC870-5-103 relay protection information interface standards; UCA2.0 (Utility Communication Architecture2.0) (set by the U.S. electric institute system of substation Communication protocol and feeder equipment); ISO/IEC9506 manufacturer information Specification MMS (Manufacturing Message Specification).

Substation communication system IEC61850 substation communication system can be divided into three layers: substation layer, spacing layer, process.

In substation layer and intervals between the network USES the abstract communication service interface is mapped to the manufacturing message specification (MMS), the transmission control protocol/Internet protocol (TCP/IP) Ethernet or optical fiber net. In the interval between the layer and process layer network using a single point to multipoint Ethernet one-way transmission. Within the substation intelligent electronic devices (ieds, measurement and control unit and relay protection) adopt a unified agreement, exchange information through the Internet.

The characteristics of the IEC61850 is 1) object-oriented modeling; 2) abstract communication service interface; 3) for real-time service; 4) configuration language; 5) the whole power system unified modeling.

IEC61850 modeling the most public actual devices and components. These models define the public data format, identifier, behavior and control, such as the transformer substation and feeder equipment (such as circuit breaker, voltage regulator and relay protection, etc.). Self description can significantly reduce the data management cost, simplify the data maintenance, reduce system downtime due to configuration error. IEC61850 based power system set up as a seamless telecontrol communication system can greatly improve the data integration of information technology and automation technology equipment, reduce the quantity, site acceptance, operation, monitoring, diagnosis and maintenance costs, save a lot of time, increase the flexibility of the during the life of the automation system. It solves the substation automation system interoperability and protocol conversion problem. Adopt the standard also can make the substation automation equipment since the description, the diagnosis and the characteristics of Plug and Play (plug-in and Play), great convenience to system integration, and reduce the engineering cost of substation automation system. In our country, using the standard series will greatly improve the technical level of substation automation system, improve the level of substation automation system safe and stable operation, saving development acceptance maintenance resources, to achieve full interoperability.

2 characteristics of IEC 61850 standard IEC 61850 standard is by the International electrotechnical Commission (International company technical appointed the 57th technical committee issued in 2004, the application in substation communication network and system of International standards. As based on network communication platform of substation, the only international standard IEC61850 standard absorbed IEC60870 series standard and the experience of UCA, at the same time to absorb a lot of advanced technology, the protection and control and other automation products and the design of the substation automation system (SAS) produced profound effect. It will be not only used in substation, and will be used in substation and between control center and control center at all levels. Major power companies and research institutions at home and abroad are actively adjust the product development direction, and tries to new international standards, to adapt to the development direction of the future.

IEC 61850 series standard of 10 categories, 14, name is not here, readers can easily find on the Internet, to introduce the following main characteristics of IEC 61850.

(1) Defines the information hierarchical structure of the substation

IEC 61850 substation communication network and system agreement draft standard puts forward the concept of substation information within the layered, substation communication system can be divided into three levels, namely the substation layer, spacing layer and process layer, and defines the communication interface between layer and layer.

(2). Using the object-oriented data modeling techniques

IEC 61850 standard USES the object-oriented modeling technology, defines the data model based on client/server structure. Each IED contains one or more servers, each server itself contains one or more logical device. Logic device contains logical node, logical node contains data objects. A data object is composed of data attribute public data named instance of a class. In communications, IED also play the role of the customer. Any a customer can be abstract communication service interface (ACSI) to access the data object and server communication.

(3). The data from the description

The standard defines the device name, logical node name, instance number and the name of the class data to establish object name naming rules; Using object-oriented method, defines the communication between the service object, for example, to get and set object values communication service, obtains the object list of communication services, data object value list of services. Object-oriented data since the description of the data source to the data itself to self description, data is transmitted to the receiver with the self, don't need to for engineering data quantity, scale conversion, etc. Because the data itself with instructions, so transmission can be defined in advance without limit, simplifies the data management and maintenance work.

(4). The network independence

IEC 61850 standard summarizes the necessary communication services, information transmission in substation was designed independently of the network and the application layer protocol used by the abstract communication service interface (acsi). In IEC61850-7-2, established standards compliant server must be provided by the communication service model, including the server model, logical device model, data model, data model and logic node set model. Client by ACSI, and the specific communication service mapping (SCSM) mapped to specific protocol stack, such as manufacturing message specification (MMS), etc. IEC 61850 standard using the ACSI and the technology of SCSM, solved the stability of the standard and the contradiction between the development of network technology in that when the network technology development as long as the change of SCSM, without the need for a modified ACSI.

Three series of IEC61850 standard IEC61850 series standards contain 10 parts:

IEC6l 850-1 basic principles;

IEC61850-2 terms;

IEC61850 to three general requirements;

IEC61850-4 system and project management;

IEC61850-5 function and device model of communication requirements;

IEC61850-6 substation automation system structure language;

IEC61850 substation and feeder equipment - 7-1 basic communication structure principle and model one by one;

IEC61850-7-2 basic Communication structure of substation and feeder for each Abstract Communication service interface (ACSI: the Abstract Communication service interface);

IEC61850-7-3 basic communication structure of substation and feeder equipment level of public data one by one and properties;

IEC61850 substation and feeder equipment - 7-4 basic communication structure of compatible one by one logical node and Data objects (DO: Data 0 bject) addressing;

IEC61850 an 8 specific Communication Service Mapping (SCSM: Special Communication Service Mapping) : in the transformer substation and spacer layer and substation layer and intervals between Communication map;

IEC61850 is a specific communication service mapping: within the interval layer and process layer and layer and process of communication between the mapping between;

IEC61850 10 conformance testing.