The proportion of cables in the urban distribution network is increasing

and the cable hybrid line

a special 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 measurement and protection element in the system

thus causing ferromagnetic resonance in the system

burn out of voltage transformer fuse in case of not serious

explosion of voltage transformer in case of serious and the safety of the operator 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 saturation characteristics

for which different saturation point voltages are set. The ferromagnetic resonance of the voltage 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 an

alyzed under different saturation characteristics. The above analysis not only provides the theoretical 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.