Остаточные напряжения как возможная причина повреждения оборудования и риска для персонала при отключении воздушных линий электропередачи. Часть 1

Abstract

To prevent substation equipment damage and to ensure safety of substation personnel under high voltage and extremely high voltage (EHV) overhead transmission line (TL) outage on the example of 500 kV TL outage voltages between switchable phase switch contacts are calculated. It is shown that under operating in the idle mode EHV TL outage, after arc clearing between switch contact connected to the phase at TL beginning and earth aperiodic voltage with the highest value exceeding the peak value of nominal phase voltage is created.The switch contact connected to the mains voltage, relative to the ground remains periodic nominal phase voltage. The resulting voltage between open contacts of the switch becomes aperiodic shifted periodic voltage with highest value exceeding the double peak value of nominal phase voltage that can cause breakdown of the switch. If there is a break switch phase, it will light the arc and switch under arc will go idle mode operating current, the voltage will recover to idle mode value, the current will stop, the arc goes out, aperiodic voltage will appear, etc. Such a process in a closed cycle can last a long time. Thus, output voltages high values can cause breakdown along the switches surface, damage to switches and health risk factor for the staff performing the bypass substation.