Study And Development Of Dynamic Simulation Testing System For Digital Protection

With the application of IEC 61850 and the popularity of electronic transducers, intelligent breakers and other IEDs (intelligent electronic devices), the substation automation system is going to digital stages. These new technology has brought significant reform to substation automation system, and also new challengers to relay devices testing. The protection equipments based on IEC 61850 (this paper called digital protection) get digital siginal of currents and voltages directly from electronic transducers and issue digital tripping signal to intelligent breakers. Such digital protection relays are different from traditional micr-computer based relays in both hardware and signal processing. The traditional relay testing methods are no ever adaptable to such new type of relays. So it has important practical significance and big applied value to research digtal protection testing methods and formulate testing standards.This paper first introduced the applied technology of digital substation, include the working principle and application problems of electronic transducer, merging unit, intelligent breaker, the contents and characteristic of IEC 61850, the network structure and data format of digital substation, the operation principle and interface technology of digital protection devices. And it also discussed the requirements for testing digital protection and the differences between traditional protection testing and digital protection testing.Based on the above contents, the paper proposed an idea for how to establish a suitable testing system by upgrading conventional power system dynamic simulation system. The main idea is parallel adding electronic transducers and merging units with exiting traditional electromagnetic transducers. And the formatted datas are sent to the digital protection devices which are tested. Meanwhile, the digital protection's tripping and closing GOOSE messages are supplied to intelligent circuit beaker controllers, digital fault recorder and other IEDs via fiber ethernet. So the testing system can perform completed test for digital protection device.Then, the paper analysised the requirements and methods for IEDs interoperability testing, and discussed the testing architecture of digital protection which was divided into universal testing and function and performance testing. With referring to the present protection testing method, the thesis formulated the detailed testing scheme for digtial transformer protection, transmission line protection, and bus-bar protection.At last, with the help of the new developed digtial protection testing platform, we completed the test of a practical digtial transformer protection using the formulated testing scheme. The prelimentary test results has showed that the new testing plantform is able to provid required secondary interface characteristic and testing environment, while the proposed testing scheme can be used to evaluate the function and performance of the IEC 61850 based protection devices.