What is the primary purpose of a surge arrestor in an EHV yard?

The primary purpose of a surge arrestor in an Extra High Voltage (EHV) yard is to protect equipment from voltage spikes. Surge arrestors are specifically designed to divert or limit surge currents caused by lightning strikes, switching operations, or faults in the system, thereby safeguarding sensitive electrical components such as transformers, circuit breakers, and other equipment from damage due to these transient overvoltages.

When a voltage spike occurs, the surge arrestor effectively provides a low-resistance path to ground, allowing the excess energy to dissipate safely. This prevents the sudden increase in voltage from exceeding the insulation levels of equipment, which could lead to catastrophic failure. Understanding the function of surge arrestors is critical for maintaining the integrity and reliability of high-voltage systems, as they play a vital role in preventing equipment outages and extending the lifespan of electrical components.

The other options, while relevant to electrical systems, do not accurately describe the specific function of surge arrestors. For instance, regulating voltage is typically the role of voltage regulators, enhancing efficiency relates to optimizing power delivery but does not directly involve surge protection, and current measurement is managed through different devices such as current transformers.