The influence of high-voltage pulse parameters on corona current in electrostatic precipitators

摘要

A laboratory electrostatic precipitator (ESP) with electrode shapes and spacing of commercial design has been energised with a pulsed power supply of high flexibility. The resulting current and charge has been measured as a function of time with fast monitors. It could be verified experimentally that the corona current prevails much longer than the length of a high-voltage pulse, since the motion of ions is much slower than high-voltage switching. Variations of pulse length between 10 mu s and 1 ms resulted only in moderate changes of the average corona current, as a result of corona self-quenching. In accordance with these observations, a very high initial pulse current was followed by an order of magnitude lower equilibrium current in a longer pulse. The initial current was strongly influenced by pulse rise time. A back corona situation was generated by high resistivity fly ash on the plates and the selection of high pulse repetition rates. It could be shown that the onset of back corona is delayed to the high-voltage pulse by the ion drift time. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 13]