A reactance relay is a voltage restrained over current relay.




A reactance relay is a type of protective relay used in electrical power systems to detect faults by measuring the reactance or impedance of the power system. It is typically used to protect transmission lines and transformers.


A reactance relay operates based on the reactance or impedance changes in the power system. It measures the voltage and current at the relay location and calculates the impedance. If the impedance exceeds a predetermined threshold, the relay operates and initiates a trip signal to disconnect the faulty section of the power system.


A voltage restrained over current relay is a specific type of reactance relay that is primarily sensitive to changes in voltage. It operates based on the ratio of voltage to current and is used to protect power system components such as transformers and transmission lines.


When a fault occurs, the voltage across the faulted section of the power system drops, and this drop in voltage is detected by the voltage restrained over current relay. If the voltage drops below a certain threshold, the relay becomes restrained and does not operate, even if the current exceeds the pickup threshold. This prevents false tripping of the relay during voltage sags or faults in other sections of the power system.


- Provides selective protection by considering both voltage and current conditions.
- Prevents unnecessary tripping during voltage sags or faults in other sections of the power system.
- Reduces the possibility of false tripping, improving the reliability of the protection system.


A reactance relay is a protective relay that measures the reactance or impedance of the power system. A voltage restrained over current relay is a specific type of reactance relay that is primarily sensitive to voltage changes and provides selective protection by considering both voltage and current conditions.