Teleprotection

Teleprotection refers to a system of protective relays and communication channels used to detect faults in an electrical power system and to rapidly trip circuit breakers to isolate the faulty section. The primary goal of teleprotection is to ensure the stability and reliability of the power grid by minimizing the duration of faults. This is achieved by allowing protective relays at one end of a transmission line to communicate with relays at the other end, enabling faster and more selective fault clearing than would be possible with local relays alone.

The communication channels can be diverse, including dedicated fiber optic cables, power line carrier current (PLCC) systems, microwave radio links, or even leased telecommunication lines. The type of communication channel chosen often depends on factors such as distance, cost, reliability requirements, and existing infrastructure. Different teleprotection schemes exist, such as permissive overreach transfer trip (POTT) and directional comparison blocking (DCB), each with its own operational logic and advantages for various fault scenarios.

When a fault occurs, protective relays at both ends of the protected equipment measure system parameters like current and voltage. If a fault is detected, these relays use the communication channel to exchange information. This inter-relay communication allows for a coordinated decision to trip circuit breakers, thereby disconnecting the faulty section from the rest of the network. This rapid isolation prevents cascading failures, reduces equipment damage, and maintains power flow to healthy parts of the system.