Laboratory-relevant corona inception of a 1-m-airgap under impulse voltage

The corona inception voltage of a point-plane airgap is studied in a climatic chamber under various test conditions: polarity of the (1-cosine) impulse voltage, humidity, artificially generated positive and negative ions, agitated air in the laboratory and various electrode materials. The lowest inception voltages are obtained, when the electrode is not treated, the laboratory´s air is not agitated, negative polarity is applied, humidity is high and negative ions are generated artificially. Under these conditions, the measured inception voltages reach minimum values and their statistical spread is reduced significantly