Simulation Analysis of Ferromagnetic Resonance of Voltage Transformer by Asymmetric Operation on Hybrid Lines
The proportion of cables in the urban distribution network is increasing,and the cable hybrid line,a spe-cial overhead line which is composed of cable and traditional overhead line,leads to the variation of capacitance of the system to ground,is extremely easy to match the non-linear inductance of voltage transformer,an important mea-surement and protection element in the system,thus causing ferromagnetic resonance in the system,burn out of volt-age transformer fuse in case of not serious,explosion of voltage transformer in case of serious and the safety of the op-erator is threatened.A simulation model of a 10 kV hybrid line consisting of an overhead line-cable is set up on the basis PSCAD,an electromagnetic voltage transformer is set up by using the UMEC model which can simulate the sat-uration characteristics,for which different saturation point voltages are set.The ferromagnetic resonance of the volt-age transformer is observed under the excitation of the high frequency transient voltage generated by the asymmetric closing operation on the line,and the total harmonic distortion rate(THD)of the primary side current of the voltage transformer is analyzed under different saturation characteristics.The above analysis not only provides the theoreti-cal basis for the correct selection and safe as well as reliable operation of electromagnetic voltage transformers in the system,but also provides technical support for avoiding damage to 10 kV electromagnetic voltage transformers.
万方数据
维普
