Electromagnetic Broadband Model Of High Voltage Power Cable And Analysis Of Its Influencing Factors

High voltage power cable is an important transmission equipment in the power grid,which is widely used in the field of power transmission,distribution in substations and industrial electricity.With the promotion of China’s urbanization construction and the development of new energy power generation,urban underground cables and submarine cables of offshore wind power are more and more widely used.There are electromagnetic transient processes when power cables fail,so it is very important to accurately model broadband cables and analyze related influencing factors.In this paper,the model of three-phase single-core cable system is established based on the theory of multi-conductor transmission line,the unit long impedance and admittance parameters of the cable are calculated,and the calculation methods of induced voltage and induced current based on cascade parameters are discussed.PSCAD and the programming method in this paper are used to calculate the same example respectively,and the results of the two calculations are compared and analyzed to verify the effectiveness of the programming calculation in this paper.Secondly,in order to better establish the electrical parameters in the high frequency range,the conductor subdivision method is used to model the cable,and the modeling process of conductor subdivision method is given in detail.Compared with the analytical formula,it is proved that the single-core cable is less affected by the proximity effect in the low frequency range,and the proximity effect becomes significant in the high frequency range,and the calculation results of the two methods are different.On this basis,a complete model of a three-core power cable with armouring is presented.The method of subdividing conductor can be used to model the finite and infinite armor thickness of three-core cable.Finally,the influence of division density on the calculation results is analyzed.Finally,the effects of cable arrangement,buried depth,soil resistivity,soil stratification and cable spacing on cable parameters at different frequencies are analyzed.The change of cable arrangement has little effect on the parameters of the cable itself,but the symmetrical arrangement structure will make the mutual impedance of the cable become consistent.Cable buried depth has little effect on cable parameters.The variation of soil resistivity in the range of 100Ω·m has a greater impact on cable parameters,and when the soil resistivity is greater than 100Ω·m,the soil resistivity has little impact on cable parameters.The change of cable spacing mainly affects the mutual impedance between cables,and has little effect on the parameters between each phase cable itself.In the case of soil stratification,the farther the cable buried from the air layer and the second layer of soil,the less the influence will be.