Discussion of the testing technology for protection device used in digital substation

The protection relays used in digital substation (called digital protection device) are different from traditional micr-computer based relays in both hardware and signal processing, and traditional relay testing methods are no ever adaptable to such new type of relays. This article analyzed the testing requirement of digital protection devices and several available testing schemes, introduced the function test method and the conformance test method of digital protection devices in laboratory. At the same time, the configuration method and testing schemes of digital relay testing instrument are introduced in detail based on engineering test practice of digital protection devices, and the deficiency in nowadays test methods was also analyzed. This paper proposed an idea that laboratory test method combined with engineering test method in relays testing, and which was a valuable exploration on the development of digital protection testing technology.