Based on the application experience of peers at home and abroad, combined with the actual characteristics of domestic integrated automation system, the microcomputer protection device of power plant has developed a high-tech product of power automation integrating protection, monitoring, control, communication and other functions. It is an ideal electrical unit for intelligent switchgear. The product has a built-in protection library composed of more than 20 standard protection programs, and has a complete and powerful acquisition function of voltage and current analog and switching value of primary equipment (current measurement is realized through protection CT). The microcomputer protection device of power plant is composed of high integration, bus parallel chip single chip microcomputer, high-precision current and voltage transformer, high insulation strength outlet intermediate relay, high reliable switching power supply module and other components. The microcomputer protection device of the switch cabinet is mainly used as the switch cabinet with voltage level of 110kV and below. Power plants, substations, distribution stations, etc. can also be used as the protection, measurement and control of the voltage and current of the system in some 70v-220v voltage level switchgear.