What is the purpose of using high speed relays and high speed circuit breakers?

High-speed relays and high-speed circuit breakers are crucial in maintaining the stability of the power system, particularly during dynamic conditions such as short circuits or other faults. The primary purpose of these devices is to quickly detect faults and isolate them from the rest of the system, which significantly enhances stability margins.

When a fault occurs, it can cause rapid changes in voltage and current that can lead to instability if not addressed immediately. High-speed relays are designed to respond in milliseconds to detect these anomalies, while high-speed circuit breakers can operate just as quickly to disconnect the faulty part of the network. By doing so, these devices prevent the fault from propagating and affecting other areas, which could compromise the entire system's stability.

The improvement in stability margins allows the power system to better withstand disturbances, whether due to internal factors like sudden load changes or external factors such as lightning strikes. This reliability is essential, especially in a deregulated market where the operation of generation units and transmission systems must adhere to strict standards of reliability and performance.