How much lower should the emergency rating be compared to the Load Dump Rating?

The emergency rating is designed to provide a level of safety for transmission systems during abnormal conditions. It reflects the maximum load that can be sustained safely for a short duration. When compared to the Load Dump Rating, which is usually the maximum permissible load under regular operational conditions, the emergency rating should be lower to account for the risks involved during emergencies.

A reduction of 3% is commonly accepted to ensure that the system is not overstressed during emergency situations. This small percentage is a conservative measure that allows the system to handle unexpected surges in load while maintaining safety and reliability.

In contrast, higher percentage reductions, such as 5%, 10%, or 15%, may be seen as overly cautious or impractical within the operational parameters, potentially leading to unnecessary limitations on power delivery. Maintaining a balance between operational efficiency and safety is critical, and a 3% reduction fits within this balance as a standard practice in transmission management.