Automatic load-disconnecting system for power networks - confines disconnections to overload regions and determines limit from frequency-voltage characteristic

摘要

The load-disconnecting system measures the power network's frequency and produces a control signal when a frequency deficit indicating a lack of power in the network occurs and persists for a given time. The network's voltage is measured and a limit indicating a lack of power is produced from the network's frequency/voltage characteristics. The given time of persistence(delay) is chosen depending on the network's instantaneous voltage such that a lower voltage results in a shorter delay.