The most operated relay for instant overcurrent protection is?

The #50 relay is specifically designed for instantaneous overcurrent protection. This type of relay operates quickly, responding to fault conditions without any intentional time delay. Instantaneous overcurrent protection is crucial in transmission systems to detect high current levels that could indicate a fault, ensuring that circuits are isolated swiftly to prevent damage to equipment and maintain system stability.

The #50 relay is favored in scenarios where the speed of operation is critical, as it can trip circuit breakers almost immediately in response to overcurrent conditions. This helps safeguard both the electrical system and its components, minimizing the risk of equipment damage and maximizing the reliability of the overall system.

In contrast, other relay types, such as the #21 (which is a distance relay) and the #51 relay (which is a time-delayed overcurrent relay), are used in different protection schemes that involve either more complex conditions or intentional delays in operation. The Static Voltage Compensator option does not pertain to overcurrent protection, as it is related to voltage regulation in the system.