ARGUS 7 is a combined check and system synchronising relay which can automatically select check or system synchronise from measurements of the relative phase angles between line and bus voltages. The relay will prevent closure of the circuit breaker if either the phase angle, slip frequency or the voltage magnitude of the incoming and running voltages fall outside prescribed limits.
If the parameters are within the limits the relay will issue an output which can be used to close the circuit breaker directly or in conjunction with an autoreclose scheme. Both the check and system synchronise functions have independent settings and blocking features. The relay includes split system detection with a variable time delay, which can be used for blocking purposes within delayed autoreclose schemes.
Synchronising bypass logic is provided to connect a dead line or bus to a live line or bus. For manual synchronising the relay includes a circuit breaker close guard feature which is used to prevent the control switch being held closed during a synchronising operation. This feature is implemented using internal logic and removes the need for an external relay.