A coil having large number of turns of fine wire is wound on the middle limb of the shunt magnet. This coil is known as pressure or voltage coil and is connected across the supply mains. The voltage coil produces a high ratio of inductance to resistance.
Differential Pilot Wire Protection is simply a differential protection scheme applied to feeders. Several differential schemes are applied for protection of line but Mess Price Voltage balance system and Translay Scheme are most popularly used.
Bus Type - Known Parameter - Unknown Parameter Load Bus -P, Q - V, phase angle Generator Bus - P, V (magnitude) - Q, Voltage phase angle Slack Bus Voltage - magnitude and phase angle - P, Q