NERC Health & Safety Institute (HSI) Practice Test

The loading on Line B if Line A trips can be determined based on the interconnected nature of the power system and the distribution of load. In this scenario, if Line A trips, the load that was being carried by Line A will need to be redistributed. This redistribution typically occurs in a way that takes into account the capabilities of the adjacent lines and the system's overall balance.

For Line B, which is taking on the load that Line A was carrying, an important aspect to consider is how much of that load can be safely managed without overloading it. The provided answer of 65 MVA suggests that this is the maximum safe limit for Line B under those conditions. It likely factors in not just the immediate demand increase from Line A's tripping but also the operational safety and reliability constraints of Line B.

This number reflects an understanding that when one line fails, it can lead to temporary surges or redistributions of load, but power systems are designed to handle certain levels of additional stress. So, 65 MVA indicates a calculated risk that ensures Line B can absorb the load increment without exceeding safety limits or jeopardizing system stability.