Study of DC Circuit Breaker of H2-N2 Gas Mixture for High Voltage

Global warming caused by such gases as CO2 is a subject of great concern. Automobile emissions are an especially great problem in this respect. Therefore, hybrid cars are being widely developed and used. Because hybrid cars use electric power and gasoline, their emissions of CO2 are reduced. The electric motor of a hybrid car is driven by a battery, which has large capacity. Therefore, relays must interrupt a high DC current on switching between the electric motor and the gasoline engine, and hydrogen gas-filled relays are used for the purpose. In interruption tests in which we investigated the basic characteristics of hydrogen gas, the DC current did not reach a current-zero point. Thus, the current must be coerced to zero by using a high arc voltage. The loss coefficient and arc voltages of hydrogen are high, and we therefore performed interruption tests using a high arc voltage. Interruption tests and dielectric breakdowns test of air, pure hydrogen, and a hydrogen-nitrogen mixture indicated that an 80%-20% H-2-N-2 mixture is the most effective. (C) 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(2): 9-17, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21042