A-C. Network Relay Characteristics

This paper discusses the required characteristics of relays for use with a low-voltage automatic network circuit breaker. The relay performs the two functions of tripping and reclosing the circuit breaker. The characteristic required for each function is discussed. The major part of the paper is given to a discussion of the reclosing function because of the danger of ``pumping'' caused by cable charging currents and various combinations of induction regulators and transformer connections. Emphasis is placed on the suitability of relays consisting of watthour-meter characteristics, construction and adjustments, involving only a different current coil and the replacement of the recording mechanism by standard relay contacts.