Analysis on several problems in carrying out generator under-excitation operation

The under-excitation operation of power generators is difficult to carry out in Guangdong power grid due to some misunderstanding on it. Therefore, the stable operational region of generators is discussed along with the analysis on relationship between under-excitation operation and loss of excitation/synchronism, end temperature rise of stator-core, and automatic excitation regulators etc. The restrictive effect of auxiliary power voltage and the safety measures of under-excitation operation are also included. It is concluded that generator under-excitation operation is a stable and normal behavior, and the difficulty of its carrying-out does not lie in technology but in people's understanding.