Electrical World

Q. Explain different types of faults? A. Shunt Faults: Basically shunt faults are short circuits. When the path of the load current is cut short because of breakdown of insulation, we say that a 'short circuit' has occurred which is nothing but a shunt fault. Series Faults: Series faults are nothing but a break in the path of current. It is observed in practice that most of the open conductor faults sooner or later develop into some or the other short-circuit fault. Q. What are the various states of operation of a power system? A. Normal, Alert, Emergency, In extremis and Restorative. Q. Explain the working of a Current transformer ? A. The current transformer has two jobs to do. Firstly, it steps down the current to such a level that it can be easily handled by the relay current coil. Secondly, it isolates the relay circuitry from the high voltage of the EHV system. A CT whose primary is in series with the line in which current is to be measured. Q. Why the se...