Wanna know about the difference between the earth fault relay and earth leakage relay ?
Then this blog is for you !!!
Before that, lets get to know about relay.
What is relay ?
A relay is an electrically operated or electromechanical switch composed of an electromagnet, an armature, a spring and a set of electrical contacts. The electromagnetic switch is operated by a small electric current that turns a larger current on or off by either releasing or retracting the armature contact, thereby cutting or completing the circuit. Relays are necessary when there must be electrical isolation between controlled and control circuits, or when multiple circuits need to be controlled by a single signal.
THE DIFFERENCE BETWEEN EARTH FAULT RELAY AND EARTH LEAKEGE RELAY :
Earth leakage relay and earth fault relay both are the electrical protective device used to protect human or electrical equipment from the earth leakage or earth fault.
EARTH LEAKAGE RELAY :
Before going to know about earth leakage relay, you must have to know what is earth leakage. When a few amount of leakage current flowing from the live part of an electrical circuit to the ground or earth then it is called Earth leakage current.
Earth leakage relay sens the earth leakage current from the unbalancing of current in phase and neutral. for a single-phase circuit, it continuously monitors if the current in both phase and neutral same or not. When a earth leakage fault occurs there will be a imbalance in the phase and neutral current. Thus the earth leakage relay can sense the leakage current and sends the signal to the main circuit breaker to trip or disconnect the main power supply.
Earth leakage relay mostly gives protection against electric shock, overheating due to earth leakage, etc. Earth leakage relay mostly used in domestic electrical circuits, wiring where earth leakage happens due to improper wiring, insulation failure, loose connections, electrical shock, etc.
EARTH FAULT RELAY :
When the live conductor accidentally touches the earth or ground part an electrical circuit or equipment then a huge amount of current will flow from the live conductor to the earth. This called Earth Fault and the fault current is called earth fault current. Earth fault relay is voltage operated device.Earth fault really is a voltage-operated device so they only work when a big amount of fault occurs. Earth fault relays are generally used in electrical substations, transformer installations where the chances of a big earth fault.Generally, the earth fault relay is installed in series with the earth or grounding wire. So when an earth fault occurs a potential difference occurs across the earth fault relay, and it sends the signal to the circuit breaker to trip the circuit or disconnect the main power supply.
Sr.no | Earth Fault Relay | Earth Leakage Relay |
1 | Earth fault relay is a voltage-operated device. | Earth leakage relay is a current-operated device. |
2 | Earth fault relay works when a large earth fault occurs. | Earth leakage relay works when small earth leakage occurs. |
3 | Earth fault relay cannot give protection against electrical shock. | Earth leakage relay can give protection against electrical shock. |
4 | Earth fault relay can work only when the earth fault current flows through the earthing or grounding conductor. | Earth leakage relay can work for earth leakage current flowing from anywhere in the electrical circuit. |
5 | Earth fault relay is less sensitive and low-cost device. | Earth leakage relay is more sensitive and a costly device. |
So, the main difference between the earth fault relay and earth leakage relay is earth fault relay is designed to sense high earth fault current which occurs due to the direct contact of any live conductor to earth. On the other hand, the earth leakage relay is designed to sense low earth leakage current which occurs due to the indirect contact between live part and earth or grounding such as insulation failure, moisturization , etc.
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