UFT TECHNIQUES FOR PHASOR ESTIMATION FOR RELAYING APPLICATIONS

Abstract

Numerical relays are the application of microprocessor technology in relay industry. Numerical relays have the ability to communicate with its peers, are economical and easily to operate, adjust and repair. Designing of numerical relays is employed to produce new prototypes and protection algorithms. So protection algorithms represent most of the early activity in computer relaying The performance of the algorithm is dependent on obtaining accurate estimates of the fundamental frequency components of a signal from few samples. So Fourier algorithm is a powerful computational tool to estimate fundamental frequency component. In this dissertation work, fundamental current is extracted from the fault signal. When fault occurs in power system, the fault current contains DC offset, harmonics and fundamental. FCDFT cannot extract the fundamental when the fault signal contains DC offset. Due to this reason the distance relay may maloperate. So various advanced phasor estimation method based on Fourier transform method is discussed. For analysis three test signals is considered and tested with varying parameters. Fundamental phasor estimation is done by various methods. Using test signals various algorithm performances is checked by varying different parameters of test signal. Comparison is done by analyzing the performance of all the method using all the test signals. The method which gives good performance is. suitable for Distance relay.