Multi-terminal protective relay system

摘要

At each of terminal connected to a protected line section a current is sampled at an identical high sampling frequency, digitized, encoded and transmitted to an associated one of the terminals with the digitized data registered in a first buffer memory. Those processes are conducted under the control of respective clock pulses. Also a receiver receives similar data from the associated terminal. The received data are decoded and registered in a second buffer memory under the control of control signals from the receiver. A shift register successively receives the data from the first buffer memory and shifts them through it under the control of a shifting pulse to compensate for a known transmission delay between the data in the two buffer memories. The shift register and the second buffer memory write respective data into a processing unit in response to a writing pulse having a pulse width of a sampling pulse multiplied by an integer from the processing unit. The processing unit compares two sets of data with each other to determine if a fault occurs within the protected section.