Cold-Load pick up when restoring can be how much greater than normal load?

Cold-load pickup refers to the phenomenon where electrical load increases significantly upon restoration of power after an outage, particularly in winter conditions when the exterior temperature is low. When power is restored, many electrical devices that were off during the outage can simultaneously draw a large amount of power. This is caused by the initial current surge as appliances, heating systems, and other loads powered up at once, resulting in a total demand that can exceed normal operating levels.

The correct answer is that cold-load pickup can be up to 10 times greater than normal load. This amount is supported by studies and operational experience, where it's been frequently observed that the heavy startup current of electric heaters, refrigerators, and other similar equipment contributes to this phenomenon.

Understanding this aspect is essential for transmission operators and system planners as it highlights the importance of considering not just the baseline load but also the potential for excessive demand during power restoration. This knowledge aids in designing adequate system protections and in managing the generation resources required during the restoration phase to prevent system overloads or failures.