Power System Protection

The task of protection system shall, together with the circuit breakers, disconnect faulty parts of the power system to:

- Protection the primary equipment against unnecessary damages.

- Enable continued service in the undamaged part of the network.

- Save people in the vicinity of the electrical plant from injuries.

During abnormal condition in the electrical circuits, high current will flow and may cause damage to the equipments. To protect the equipments from high fault current, the faulty portion of the power system shall be isolated by means of protection devices (fuses, MCB or relays). Hence the function of the protection is to isolate the faulty section.

The correcting measures can be initiation of regulation interference, disconnection of some part of the load, connection of back-up capacity or, as a last possibility, disconnection of the critical apparatus. Mostly of these precautions are initiated by protection relays which supervises the condition in the electrical equipment.

In order to understand the philosophy of the protection, consider the simple example of domestic electrical wiring. In the house we have one Main MCB (incomer) and routed through the branches to different rooms through MCBs or fuses. When there is a fault in any of the branches, the MCB related to that branch will be switched off keeping other branches healthy. the main MCB shall be of higher rating than the MCB in the branches in order to isolate the branches first. Thus we can achieve the protection of the equipment during abnormal condition.

This is just a snapshot on the importance of power system protection. Power system protection is a specialized field where the learning and search for advanced knowledge is continuous. We hope see you guys in our future blogs. Cheers.