Reset Factor
The Reset Factor refers to the speed of a relay’s reaction. The closer the return coefficient, the faster the relay’s response.
Why is it important to understand the Reset Factor?
To clarify this extremely important aspect, we will pretend that a fault happened in an electrical circuit & the value of the current exceeded the specified value. Pickup current caused the Protection Relay to start counting down the time set for it before sending the separation signal (Trip) to the key.
How can it be tested on-site?
We presume the issue was temporary & the fault current immediately decreased before the relay activated.
The protective device is expected to swiftly reverse the initial decision to disconnect the circuit owing to low current and state that it has happened to him.
Drop Off
The Reset Factor might be tested for any Protection Relay by any Secondary Injection by injecting a current on the Relay & progressively increasing it until the Protection Function works and closes the Output Contact of trip.
Pickup
We steadily reduce the current until the Output Contact opens, indicating that the Relay has dropped off.
Reset Factor Calculation
The Reset Factor is always near to one and may be calculated as follows.
Reset Factor = Drop-off/Pickup