Which term describes the condition when transmission lines or substation Equipment are loaded between 90% and 100% of their continuous rating?

The term that best describes the condition when transmission lines or substation equipment are loaded between 90% and 100% of their continuous rating is critical loading. This terminology is significant in the context of power systems because it indicates a situation where the equipment is approaching its maximum operational capacity, which may affect reliability and performance.

Operating at this level implies that any small increase in load could lead to overheating or equipment malfunction. It’s essential for utility companies to monitor these conditions closely to avoid potential failures. Critical loading requires careful management and response strategies, as it could lead to system instability or interruptions in service.

While normal loading refers to operational levels well below the maximum capacity, oversaturation typically implies exceeding the maximum capacity, which can lead to risks of failure. Peak capacity often indicates a temporary maximum load condition but does not specifically denote the loading range crucial for ongoing operational stability. Thus, critical loading accurately captures the essence of being in a high-risk operational range.