NERC System Operator (SOS) Practice Exam

Relay protection is a critical method used to safeguard the power system from abnormal current or voltage surges. This method operates by continuously monitoring the electrical parameters of the system, such as current, voltage, and frequency. When the relay detects conditions that exceed predefined thresholds—indicative of faults or abnormalities—it triggers protective devices to isolate the faulty section of the power system. This not only helps to prevent damage to equipment but also ensures the stability and reliability of the electrical network.

Relays serve as the brain of the protection system, as they perform complex logic to determine when and how to initiate protective actions. They can coordinate with other protective devices, ensuring that the disruption is minimal and that the system can recover quickly after a disturbance. Relay protection can be applied to various situations, including short circuits, overloads, and other fault conditions, making it a versatile and essential component of power system protection strategies.

The other methods mentioned, such as fuse protection, overcurrent protection, and capacitor banks, have their specific applications and limitations but do not encompass the comprehensive protective capability and intelligence that relay protection systems provide.