Research On Digital Protection Devices Test System Based On IEC61850

IEC61850, as the common international standard for substation, is widely used in China to bring great opportunity for digital substation. With IEC61850 standard, information sharing in substation can be easily executed, and device functions can be greatly enhanced. Rapid development of computer and network communication technology, a large number of access of multifunction IED and electronic transformer which meet IEC61850 standard, that raise operation efficiency of substation system, and promote development of digital substation. While significant changes in substation, new challenges have brought to relay test. In digital substation system, as the design, structure, operation, etc. of information own nature, transmission medium, transmission mode and relay devices have greatly changed, so the traditional relay test methods are no longer applicable and a relay test system for digital substation, which meets IEC61850 standard, is urgently needed. As a result, depth studying relay test methods for digital substation and developing new relay test system have important practical significance.This paper firstly overviews the characteristics and key technologies of digital substation, including:basic elements and core technologies of IEC61850; characteristics and work principle of electronic transformer, merging cells and intelligent circuit breaker; communication mechanism of digital substation process level and analyzing the sample transport mechanism meeting IEC61850-9-2 standards.Then it introduces the internal structure, functions and implementation of WinPcap web development system, and analyzes the structural features of digital computer protection devices based on IEC61850. On this basis, the program of digital substation relay test system is proposed, then using PSCAD and interface converter unit based on development of WinPcap data packets to build a software protection device test system and implement static test for relay. Its main features are the abilities to simulate multi-interval merging unit sending data to relay device and freely control the failure time without changing the simulation parameters.Finally, by experiment to verify the function of test system, including sending samples based on IEC61850-9-2, receiving and analysis for GOOSE message. Tests show the system runs well and reach the expected targets.