Elektrospin

The basic operating principles of the most common types of protection relays have not changed for more than half a century. The relays measure the major attributes of power system fault signals, such as fundamental frequency component, harmonics, magnitude and phase angle of voltages and currents.

The Fourier transform is commonly applied for measuring these attributes in a long and fixed sampling window of the fault signals. And at the same time, complex calculations of the Fourier transform have to be undertaken during each sampling interval. These calculations cause many problems for the relay performance, in terms of fast response, accuracy and reliability. As a result, there is a need for developing a next generation of protection relays which are more accurate, more reliable and faster than the conventional relays.