Directional overcurrent protection is a type of electrical protection that is designed to detect and respond to abnormal current flow in a specific direction. It is typically used in systems where the normal flow of current is known and expected, and any deviation from that flow is indicative of a problem that needs to be addressed. For example, in a power distribution system, current flowing in the opposite direction of the normal flow would likely indicate a problem such as a short circuit or a fault on the line. In such cases, the directional overcurrent protection would trip or open the circuit to prevent damage or injury.
On the other hand, Non-directional overcurrent protection, is a type of electrical protection that responds to any abnormal current flow regardless of the direction. It is typically used in systems where the normal flow of current is not known or expected, and any deviation from the normal current level is indicative of a problem that needs to be addressed. Non-directional overcurrent protection is often used in conjunction with other types of overcurrent protection, such as directional overcurrent protection, to provide a more comprehensive level of protection for electrical systems.