The limit is defined by the electrical load (burden) of the relays in relation to the maximum terminal voltage. Ratios are stated as “X” primary current to 5A i. Protection engineers calculate the maximum load current, the minimum fault current, and the full range of possible voltage levels to ensure relay. PSM represents how many times the actual current is above the relay's current pickup setting. The relay settings that are selected are often a compromise in order to cope with both overload and. Combines protection, sensors, control power, and circuit breaker in a single package Typically added to a breaker close circuit to prevent accidental reclosure after a trip. It functions as a watchdog by constantly surveying multiple system components including voltage, current, frequency, and phase angle. It. The selected protection principle affects the operating speed of the protection, which has a significant im-pact on the harm caused by short circuits.
