The application provides a kind of
relay protection system and method, comprising: the real-time current data of the inflow in the equipment to be protected is collected, and the real-time current data is converted into
digital signal after A / D conversion;According to the current data after A / D conversion, the
heat capacity is calculated, and according to the
relay protection time under the setting of different multiple rated current, the integral value operation of current
thermal effect is carried out, and the
overcurrent inverse
time limit action time is determined.The application realizes the
relay protection of multiple systems based on
microprocessor and other
hardware circuits, the real-time current data of the protected equipment is collected by hardware device, and is converted into digital quantity after AD conversion, the calculation is carried out through
microprocessor, according to the relay protection time set, integral operation is carried out,
overcurrent inverse
time limit action time is calculated, instantaneous operation of relay protection is realized, calculation precision is high, action is reliable, application is flexible, inverse
time limit action time of different rated current multiple can be set according to needs, and the application range is wide.