The main purpose of the Electrical Protective Relays are to detect the fault . This also should got the capacity to redundant and need to interrupt the power supply. Even the fault is occur in such system the system is design to not to interrupt the entire system. Distance protections can also use to get protect from transmission lines.
Any fault in a part of the electrical system can interrupt the whole system. So protection devices need to isolate the fault part from the entire system to maintain the stability of the system. Protective relays use for get protect from the system.
Purpose of Electrical Protective Relays
The main purpose of the protective relays are to detect the fault . This is alus use to start a trip or disconnect connection by giving signal to disconnect the supply.
Protective relays are use to detect and measure the certain faults occur in system.
Protective relays is also an electromechanical device which use to control , protect and detecting purposes. Normally protective relays are widely used to control the circuit breakers and switches.
Operation of Protective Realays
This relay is also use to detect the exceeding of the current, voltage and frequency of the system. Relays take into action to open-circuit breaker and disconnect power supply in case of any fault in the system. There are secondary relay which is also used as backup protection system . Under normal operation condition the output is “0”
Relay is simply an electrically operated switch . The working mechanism of the relay mostly mechanical and there is electromagnet use to operate the switching. There are different types of relays use for different types of purposes.
Types of Relays
There are several types of protection relays are use in electricl protection systems such as.
- IDMT relays
- Programmed Switches
- Definite Time Electrical Protective Relays
- Instantaneous Relays
- Distance Relays
Protective Relays Functions
Protective relays are function on detect the fault and also to start the appropriate control signal such as the tripping signal. Protective realays are the equipment which send small signal to circuit breaker when fault occur in the system. So circuit breaker can open this circuit and isolate the electrical path.
As we discuss earlier the main purpose of this relays are first detect the abnormal conditions and give feed signal to nessary circuit breakers. Protective relays are work with high voltage circuit breakers.There are several relays re-use in power system to protect the entire system.
If you are use only one relay on circuit breaker operation , when this relay malfunction or not work this will cause to have hazard situation to entire power system. So there are several Electrical Protective Relays are use to work with circuit breakers . When one relay not working other relay will work and give the signal to circuit breaker to operate.