The Real-Time Performance Of Communication Network In Distributed Intelligent Feeder Automation System

Feeder automation (FA) can locate and isolate fault line in distribution network. And it can restore power, reduce the fault outage time and blackout range and improve power supply reliability. With the development of communications and computer technology, distributed intelligent feeder automation (DIFA) has been developed. Feeder terminal unit (FTU), which is installed at the feeder switch, communicates fault information with each other through peer-to-peer communication network. It reduces non-failure section of the power outage time to second level. So the trip control information must transport in a very short time. Now generic object oriented substation event (GOOSE) can solve the real-time problem, but it must build anther network to transport the control information. All those limit GOOSE used in DIFA system.If it is guaranteed to the control information transmission real-time performance with the existing communication network in distribution network, and it transport the remote control, remote signaling, telemetry and control information to fulfill DIFA without extra investments in communication. Therefore, researching the real-time performance of communication network in DIFA promote its application in the distribution network.This paper analysis of the DIFA principle, communication systems, implementation of peer-to-peer communication, TCP/IP protocol, common networking, as well as the communication protocol of real-time effects. Therefore, this subject on the research on several areas of content:1. Study FA system features, implementation, advantages and disadvantages of the comparative analysis of centralized and distributed intelligent feeder automation. Introduce of open, closed ring DIFA system. We can get a conclusion that DIFA restore power in the open and closed ring.2. Analysis of communication system requirements in distributed intelligent feeder automation system. Study the implementation of peer-to-peer communication, TCP/IP protocol, common used networking (Industrial Ethernet, EPON, wireless Ethernet).We can get a conclusion that industrial Ethernet networking is a better approach.3. Analysis of Shared Ethernet real-time performance, and qualitative analysis of the transmission delay and network traffic. Analysis of interactive Ethernet real-time performance and compute communication delay. Analysis of the Ethernet communication protocol for real-time impact. Theoretically come to the Industrial Ethernet real-time performance meet the communication requirements of DIFA. 4. Verify of network traffic on Industrial Ethernet communication delay by experiments. Results show that when the network load control below35%,the network communication delay can be controlled at about0.2ms; when the network load is greater than35%, the communication delay will significantly increase, from5ms to about20ms.In this paper, the real-time performance of communication network in DIFA is researched. And the method of controlling real-time network is proposed. It is important practical significance for the development of DIFA in distribution network.