An Communication System Of Microprocessor-based Segrregated Differential Pilot Protection Based On HDLC Protocol.

With the swift and violent development of the real-time communication of the power system, reliable real-time information is a basic foundation of system operation. Communication is a route to obtain real-time information. An accurate and prompt communication is essential to correct movement of the system. Power system relay protection's communication network system structure, choosing and realizing of application layer protocol plays a decisive role to the advance of the whole system.This literary adopt a High-level Data Link Control protocol(HDLC) which faces bit, choose the serial communication controller in conformity with it, make HDLC realized conveniently through initializing the hardware. By the look of the dependability and efficiency of data transmission, it have improved a lot more than the past asynchronous way and byte-oriented synchronous communication way.At present, microprocessor-based protection has already been used on the transformer substation , power plant and transmission line of the power system in a large amount. Use a new protection principle is an important aproach to ensure quick and correct switching off faults and maintain power system stability. On account of influence of current transformer saturation and distributed capacitive currents of the protected line,great unbalance current will be produced during external faults and make protection to mal-operation,so some restraining measures must be adopted. This text applies an adaptive principle put forward recently to the microprocessor-based segrregated differential pilot protective device. Characteristic of the brake of this principle demonstrate a non-linearly strengthen with increase of opposite terminal's electric current, which fully guaranteeing the security at the time of external trouble and sensitivity at the time of the internal trouble.This system uses a latest Optical current transformer developed by North China Electric Power University. For the dependability and real-time character of the system operation, some measures have been taken in the data coding way and...