Development of Generator Protection using Multifunction Numerical Relay in Laboratory
|N. G. Chothani1, A. K. Desai2, M. B. Raichura2 and A. S. Chaturvedi2
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A 3-phase synchronous generator is a vital component of power system and thus requires a dedicated protection system. To protect the generator against the adverse effects caused by abnormal or fault condition in power system or within the generator itself, it requires quick isolation from the system. In this paper, a laboratory setup has been developed to cater various protections applicable to scaled generator. In this work, a 3-phase circuit has been simulated including generator, measuring equipments (CTs & PTs), circuit breaker and variable load bank. A control circuit comprising of main relay and auxiliary relay has been developed for the protection of generator. A multifunction numerical relay (MiCom P341) is used to provide various protection features such as overload/overcurrent, over/under voltage, over/under frequency and restricted earth fault (REF) protection which are employed in actual field. The analog signal captured from the secondary of CTs and PTs are given as an input to relay which has an inbuilt high speed processing unit. As per the rating of generator, various parameter settings related to particular protection feature has been calculated by authors and given to the relay. The relay operates successfully and isolates the generator during all abnormal or fault conditions within the set time. The experimental results confirm the satisfactory operation of the developed laboratory prototype.