What frequency is considered ideal before restoring a block of load?

The ideal frequency range before restoring a block of load is typically established around 60-60.5 Hz. This range is considered optimal for several reasons. First, operating near the nominal system frequency of 60 Hz ensures stability and reliability within the power grid. Restoring load at this frequency helps maintain the balance between generation and load demand, which is critical for preventing frequency-related issues that could lead to outages or equipment damage.

By starting to restore load at frequencies slightly above the nominal value, in this case, up to 60.5 Hz, the system can be assured that it has sufficient reserves and that the generation is stable. If load is restored at frequencies significantly different from the nominal value, it could result in operational challenges, such as oscillations or equipment stress, thus making the 60-60.5 Hz range a safe and effective choice for reintroducing load.

This understanding underscores the importance of frequency monitoring in transmission practices, particularly as restoration decisions are made in response to system conditions.