Overvoltage on transmission systems caused by dropping load

THE INCREASE in voltage resulting from total or partial loss of load is especially undesirable on waterwheel driven generators because of their regulation characteristics and the fact that they are frequently connected to long lengths of high tension transmission line. The charging current of such lines results in a further increase in voltage. Although various types of relays have been used to trip the generator on the occurrence of excessive voltage or speed, a more desirable method of limiting the voltage is by the use of generator voltage regulator acting in the generator or exciter field circuit.