Real Time Load Angle Application for Synchronous Generator Protection Purposes

The out-of-step protection function is one of the key functions in generator protection. This function detects the loss of generator synchronism, and when such a fault occurs, it is necessary to disconnect the generator from the rest of the system as soon as possible in order to avoid major damages. The algorithms used in the out-of-step protection functions are based on the measurements of generator impedances and they use the impedance vectors to check if all stability criterions are met. This paper describes a new approach to realizing the out-of-step generator protection function by using the direct load angle measurement. The idea behind applying the real time load angle measurement is to faster detect the loss of synchronism.