继电保护3（Relay protection 3）.doc

继电保护3（Relay protection 3） 2 、 configuration and application of relay protection in power system 2.1 the task of relay protection device Relay protection mainly uses the change of the electric quantity (current, voltage, power, etc.) in the short circuit or the abnormal circumstance in the electric power system to constitute the relay protection action. The task of the relay protection device is that, when the power supply system is operating normally, safely. Operation status of complete monitoring of various equipment, provide a reliable basis for the operation of the personnel on duty; fault occurs in power system, the fault automatically, quickly and selectively, to ensure that non fault section will continue to run; when the abnormal operation work in the power supply system for the situation, it should be timely and accurately issued signal or alarm, inform the officer on duty as soon as possible to make a deal. 2.2 basic requirements of relay protection device 1) selectivity: when there is a fault in the power supply system, the relay protection. First, disconnect the nearest circuit breaker from the point of failure to ensure that other non fault parts of the system continue to function properly. 2) sensitivity: the sensitivity of a protective device is generally measured by sensitivity coefficients. In the scope of protection relay protection device, no matter how, no matter how short the location of short circuit properties, protection device should not have to act; but the fault occurred in the outside protected areas, and should not have the wrong action. 3) quick action: means that the protection device should be as fast as possible to remove short circuit fault. Shorten the time to remove the fault and reduce damage of short-circuit current on electrical equipment, accelerate the recovery of the system voltage, so as to electrical equipment from the start to create favorable conditions, but also improve the stability of the generator in parallel operati