Voltage and Frequency Relay Block 7SG118 With (3 Pole)

Features and technical specifications:

1. CT inputs : 3 No’s
2. Binary inputs : 1 No
3. Binary output’s : 4 NO & 3 C/O
4. RS 485 Communication Port

The following functions are available

1. 2 or 3 voltage inputs
2. Under/Over Voltage
3. Negative phase sequence over voltage
4. Neutral voltage displacement
5. Under/Over Frequency
6. Under voltage blocking
7. Fibre optic or RS485 electrical communications port

This Voltage and Frequency Relay Block is easily insert in your schematic diagram and connect as you like way.

The relay provides phase under and over voltage, neutral displacement over voltage, negative sequence over voltage
and under and over-frequency protection elements.These relays have extensive protection functions, which are supplemented by advanced metering, data storage and communications. Supervisory and self monitoring features give added confidence to the user as well as reduced maintenance and down time. A menu-based interface gives user-friendly access to relay settings, meters and operational data. Serial communications conform to IEC60870-5-103 or Modbus RTU protocol. Up to 254 relays may be connected in a ring network and addressed individually. A fibre-optic communications port is provided on the rear of the relay. It is optimised for 62.5/125μm glass fibre using ST® (BFOC/2.5) bayonet connectors. Optionally an RS485 electrical connector can be provided.

Application :-

1. Under voltage and over voltage:-
Four independent elements are supplied, each of which can be set to operate for under or over voltage conditions. Each
has separate definite time delay elements. These can be used to protect generators against over-voltages, motors against loss of supply or applied as backup protection in the event of defective system regulating equipment.
2. Negative sequence over voltage :-
Two independent elements are supplied, each of which has a definite time delay element. These can be used to monitor
the quality of the supply and protect plant against system unbalance.
3. Neutral voltage displacement :-
Two independent elements are supplied, each of which has a definite time delay element. These can be used to detect
earth faults in high impedance earthed or isolated systems. For this feature, the residual voltage can be measured
directly from an open delta tertiary winding or (for 3-phase variants) calculated internally from the phase voltage inputs. These elements include a third harmonic filter, which desensitises the elements to any superimposed third harmonic frequencies.
4. Under frequency and over frequency :-
Four independent elements are supplied, each of which can be set to operate for under or over frequency. Each has
separate definite time delay elements. These can be applied wherever frequency protection is required to maintain
system stability e.g. in load shedding schemes. The accuracy and security of operation of the numeric algorithms enables the relay to be employed to detect any frequency abnormalities.