What benefit does high-speed transmission protection provide to angle stability?

High-speed transmission protection plays a critical role in enhancing angle stability by reducing angle spread in the electrical system. Angle stability refers to the ability of interconnected generators to maintain synchronism and continue operating together during normal and disturbed conditions. When a fault occurs in the transmission system, such as a short circuit, it can create a significant difference in phase angle between generators. This angle spread—essentially the difference in angular position between machines—can lead to loss of synchronism and system instability.

When high-speed protection systems are employed, they can quickly detect and isolate faults, thereby minimizing the duration that generators operate under faulted conditions. This rapid response reduces the angle difference that develops between generators, enabling the system to return to a stable operating point more quickly. Consequently, by limiting the angle spread during disturbances, high-speed transmission protection contributes to maintaining system stability and preventing cascading failures.

The other options do not accurately reflect the impact of high-speed transmission protection on angle stability. Increasing fault duration would likely exacerbate angle instability, while reducing system load and decreasing transmission efficiency are unrelated to maintaining synchronous operation among generators.