Design of an Automatic Testing System for AC Sampling Plugin of Relay Protection Devices

Relay protection devices play an indispensable role in the secondary equipment of substations, safeguarding the safe, stable, and reliable operation of power grid. AC sampling plugins are mainly used for voltage and current analog data acquisition in the secondary circuit system of relay protection devices. The relay protection device uses the collected data for logical operations to control relay actions, alarms, etc., and the accuracy of these results directly impacts the functional realization of the entire relay protection device as well as the safety of the power system. This paper designs an automatic test system for AC sampling plugins, which can calculate the compensation values of the ratio coefficient and angle difference of each channel of the AC sampling plugins during testing, improving the accuracy of sampling values and greatly enhancing production testing efficiency.