Development of on-line real-time PC based frequency meter and frequency relay for monitoring, control and protection of HV/ EHV power system

In this paper an attempt has been made for measurement of frequency and development of frequency protection relay by simulation in a PC. System has also been developed to interface the HV/EHV power system with the PC. Development of the measurement process and also the relay has been simulated with software Simulink (Matlabtrade). For interfacing at the input, a set of hardware has been used. The output signal is generated from the analog output block of the relay unit and finally sent to the LPT1 port of the PC. The generated output signal, which sends the trip signal to the parallel port, is interfaced to the physical system. Through "digital to analog converter (DAC 0804)" the signal turns to an analogue signal. This signal further amplified and is used for monitoring, control and protection of the equipment depending on different frequency range and the logical condition framed in elements of the relay unit