The relay measures the line current from each of the line CTs and if the current exceeds the set threshold, then relay extends a trip signal atier an operating time. The relay's “operating time” is determined by selecting “definite time” or one of the six “inverse time” characteristics. This principle of relaying is equallyapplicable to both line and earth fault protection elements (51N / 51G).

This feature can be useful in providing better selectivity in the operation of over current relays, by preventing them from operating, during inrush phenomenon.

known as single- phasing)for certain strategic purposes, conventional earth fault relays in substa- tions would pick-up and trip the circuit breaker. This operation is considered by the engineers as an undesirable outcome of a planned current un-balance in the system. “MIPConS”, when enabled, automatically detects the single-phasing operation and restoration of 3-phase system. Consequently, the feature prevents “earth fault element” from extending trip command under single-phasing conditions.

The trip test will facilitate testing of relay operation without applying the input current. The trip test is useful to test the panel wiring and operation of breaker without any current. The trip contact will operate instantaneously. The phase and earth fault alarm contact will not operated during the trip test.

A simple earth fault protection may not provide adequate protection for transformer windings particularly when in the case of "Y" connected winding earthed with an impedance. The efficacy of protection is improved by employing restricted earth fault protection. The said protection scheme is prevalent even under the case of “solidly earthed systems”. High-impedance protection scheme requires the residual current derived from the three line CTs to be balanced with the "neutral current" derived out of neutral CT. This unit protection scheme is generally sensitive only to the fundamental harmonic component of the measured current and has an "instantaneous time" as its operating characteristics.

Relay has a multi shot auto re-closer facilitates automation for breaker operation. Auto re-closer can be programmed to provide a maximum of five shots. “Dead time” starts when a trip signal is provided due to the occurrence of a fault involving L-L or L-G or L-L-G or L-L-L or L-L-L-G. Atier an elapse of a time interval equal to “dead time”, closing command will be extended. The “reclaim time” timer starts at the instant when the “dead time” timer expires. If atier extending the “breaker close” signal an over current fault was detected before the “reclaim time” timer reached its terminal count, then the relay understands that the fault in the system is still persisting and the over current relay will issue a trip signal. The relay tries to close the breaker for a maximum of the programmed number of shots before it chooses to lockout. The relay can be configured for independent trip sequence as IDMT or Definite time.

TCSR monitors trip coil continuously. If the trip circuit (or any coil) that is being supervised develops a snag, then the supervision relay extends an alarm without a delay. The relay monitors the trip coil under all the states of a breaker viz. close, open and during transition. The underlying mechanism of supervision is to perform hi- impedance measurement across two input circuits appropriately wired along with trip coil, 52A and 52B auxiliary contacts. 1-NO & 1-NC contacts have been provided for the purpose of alarm and SCADA. The current rating of these contacts is 5Aat 24VDC / 230VAC.

Self supervision feature allows the operator to take note of any internal failure in the relay. An LED and an output contact is provided for annunciation purposes.