Abstract:

To meet the testing needs of medium and low voltage DC switching device in rail transit,new energy and other fields,a large-capacity DC short-circuit test platform has been developed.The AC side power supply of the test platform adopts the optional 10 kV grid power supply and short-circuit impact generator dual-circuit option.The maximum short-circuit capacity reaches 3 200 MVA,and the maximum test capability reaches 2 kV/350 kA or 6 kV/120 kA.The platform adopts twelve pulse rectification technology,and the ripple coefficient of the DC output signal is less than 1.5%.A short-time withstand current test was conducted on a DC circuit breaker with a short-time withstand current of 150 kA and a withstand time of 200 ms.Additionally,the short-circuit breaking capacity tests was seperately perfomed on a DC fuse rated at 1 500 V voltage and 250 kA rated short-circuit breaking current,as well as on a DC circuit breaker designed for rail transit,which can withstand a short-circuit current of 135/95 kA under maximum fault conditions.The result show that the test platform can provide test current,ripple coefficient and time constant that meet the product needs and the standard requirements.

Key words: medium and low voltage DC switching device, short circuit breaking capacity test, high current testing technology, DC circuit breaker