Which device is used to manually open or close an EHV breaker?

The device used to manually open or close an Extra High Voltage (EHV) breaker is indeed the maintenance closing/opening device. This tool is specifically designed to facilitate the manual operation of circuit breakers in cases where automated systems are either unavailable or in need of maintenance. EHV breakers are critical components in power distribution, and the maintenance device ensures that personnel can safely engage or disengage the breaker without relying on electronic control systems.

The maintenance opening/closing device provides a safe and reliable means of operation, typically featuring mechanisms that allow the user to exert the necessary force to operate the breaker without causing damage or compromising safety. This is particularly important in high-voltage situations where the risk factors are elevated.

While other devices such as electrical actuators or pneumatic valves are indeed part of automated systems in modern substations, they are not specifically designed for manual operation. Using a mechanical wrench could potentially damage the breaker or create unsafe conditions, as manual intervention requires specific design considerations that standard tools may not provide. Therefore, the maintenance closing/opening device is the appropriate choice for safely managing EHV breakers in manual operation scenarios.