In what scenario would the backstopping system prevent fault propagation?

The backstopping system is designed to protect the electrical network from conditions that could lead to fault propagation, particularly during instances of overloading. In a scenario where overloading is detected, the backstopping system executes protective measures, such as disconnecting certain segments of the network or reducing the load, to prevent excessive stress on the equipment. This proactive approach helps to mitigate the risk of faults spreading to other parts of the system, which could potentially lead to widespread outages or damage.

For instance, when a system experiences overload, components may be subjected to heat and stress levels beyond their rated capabilities. By activating the backstopping mechanisms, the system can isolate the affected area, thereby containing the problem and ensuring that it does not escalate and affect the entire network.

In contrast, the other scenarios do not directly invoke the need for a backstopping response in the same manner. Disconnecting the main supply, while potentially protective, does not facilitate immediate action against an existing fault. Regular maintenance checks are preventive measures, and voltage fluctuations typically do not require backstopping unless they lead to specific overload conditions. Hence, the context of overloading is what specifically aligns with the effective use of a backstopping system.