• Emco Electronics

Voltage Regulating Relay

Emco Electronics offers an integrated automatic Voltage Regulating Relay, type EE-301T, designed for operational simplicity. It regulates the secondary voltage of power transformers with on-load tap changers. The bandwidth control allows the deadband to be set in terms of raise and lower voltage limits around a particular nominal value with specified sensitivity. The time delay control allows the regulator to respond only to the voltage fluctuations lasting for periods greater than the selected time delay. Where the voltage correction requires more than one tap change, the time delay is re-initiated before further tap changes. No special provision is required to reset the time delay, which resets automatically after the voltage correction. Solid-state lamps (LEDs) indicate voltages outside the preset limits and control relay operations. Operation of the raise/lower control relays is automatically inhibited when the voltage falls below the specified undervoltage limit/goes above the over voltage limit. One pair of normally open relay contacts is provided to effect the tap changer raise and lower operations and to trigger an alarm in case of undervoltage/overvoltage conditions. An alarm in the form of normally open contacts has been provided in the same cabinet in case of control failure, i.e., AVR relay continuously showing either 'L' or 'R' command for more than 15 minutes due to malfunctioning of AVR/OLTC/any other reason. An in-built tap position indicator is provided for indicating the tap number of power transformer with 1 k? step resistances for a maximum of 35 taps. 4-20 mA TPI output for Scada can be optionally provided in the same cabinet. For compensating line resistance and reactance at different load currents an optional line drop compensator can be provided in the same cabinet. An alarm in case of auxiliary supply failure can also be provided in the form of normally close contacts in the same cabinet.