Functions :-
Analogue values can be displayed in primary or secondary quantities on the LCD screen. In addition the values can be obtained via the communications port.
1. Primary voltages
2. Secondary voltages
3. Frequencies
4. Phase angles
5. Status inputs
6. Output contacts
Application:-
Check or system synchronising is required whenever two parts of a power system network, each containing generation, have to be connected or re-connected together. To avoid shock loading and possible damage to primary electrical plant the voltage, frequency and phase angle difference between the two systems should be within acceptable limits relative to one another. Where the two systems have been previously interconnected, then the frequencies of the two systems will drift apart slowly following circuit breaker tripping and the phase angle
difference will increase. Here the slip rate will be small and the circuit breaker can be closed using check synchronising settings as the limiting parameters. However, if the two systems become asynchronous so one system is an ‘island’ of generation then a high rate of slip may result causing the two systems to pass through anti-phase
conditions. The relay will detect this system split condition, inhibit the check synchronising algorithms and automatically apply system synchronising settings as limiting parameters. Typically in this mode the slip rate will be much higher and so there will be a narrower allowable phase angle difference before closing. In addition, closure of the circuit breaker will only be allowed under conditions of decreasing difference in phase angle.
The 7SG117 Argus 7 is a combined check and system synchronising relay which can carry out controlled closing of a
circuit breaker using measurements of the line and bus voltages. The relay will prevent closure of the circuit breaker if the differences in phase angle, slip frequency or magnitude of the voltages fall outside prescribed limits. If the parameters are within limits, the relay will issue an output which can be used to close the circuit breaker directly
or in conjunction with an auto reclose scheme. Relays are part of the comprehensive range of Argus-platform
based numeric relays. They have extensive control functions, which are supplemented by advanced metering, data storage and fibre-optic communications. Supervisory and self- monitoring features give added confidence to the user as well as reduced maintenance and down time. Reydisp relay interrogation software gives user-friendly access to relay settings, meters and operational data.
Reviews
There are no reviews yet.