The Source and Nature of Transient Surges

Sources of transient voltages or surges due to various phenomena normal to the power station environment are described along with typical waveforms and other parameters of the surges coupled into control circuits. The mechanism by which surges are generated by switching of inductive devices in low voltage control circuits is described in detail. The importance of the contact restrike action in creating and coupling very short duration transients onto the control bus is evident. Oscillograms of such a transient generated by operation of a typical auxilary relay circuit are included.