Abstract-Capacitive current interruption with air-break disconnectors in a high-voltage network is an interactive event between the circuit and arc with a variety of interruptions and reignitions. In this contribution, first, a theoretical analysis related to this interaction is presented. The effect of capacitances at the source side ( ) and load side ( ) is investigated. Three distinct frequencies are identified as contributing to the voltage and current events in the circuit. Besides the power frequency quantities, a medium frequency transient arises related to the excursion of voltage across capacitances to the applied voltage, and a high-frequency transient arises due to charge redistribution between load-and source-side capacitance at reignition. Second, experimental results from an interruption measurement are studied in detail. Typical waveshapes of voltages across the capacitances, disconnector, and currents through the disconnector show that the transients during interrupted are in agreement with the theoretical analysis. Reignition voltage of the air gap and energy input to the arc on reignition are also studied. It is concluded that besides a higher interruption current and a higher power supply level, a lower ratio leads to more severe interruption and longer arc duration. Finally, the actual status of IEC recommendations on testing, that has taken into account this arc-circuit interaction, is summarized.

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Capacitive current interruption with air-break disconnectors in a high-voltage network is an interactive event between circuit and arc with a variety of interruptions and reignitions. In order to investigate this transient phenomenon, a series of interruption tests was performed at KEMA High Power Laboratory. In this paper, a brief analysis of the interruption process is presented and is compared with experimental data from the test. Typical wave shapes of voltages across the capacitances, disconnector and current through the disconnector are given. Re-ignition voltage and energy input to the arc on reignition are also investigated. Comparison shows that the test data are in good agreement with simulation. It is concluded that besides higher interruption current and higher power supply level, a lower ratio between source side and load side capacitance leads to more severe interruption and longer arc duration. In the end, the actual status of IEC recommendations on testing, that has taken into account this arc-circuit interaction, will be discussed.

A study was performed to seek out inadvertent connections between neutral and ground in the power distribution system of a newly constructed hospital, prior to occupancy. Such connections are not only violations of code but could cause medical device problems. Ground wires are not intended to carry load currents except during faults. When currents do flow in grounds, medical device chassis voltages are elevated and some devices may respond unpredictably. Suitable acceptance testing is not commonly done. In this study, a simple test method was developed that helped reveal and correct many neutral-ground misconnections. The authors advocate incorporating such a test into building construction contract specifications.