Extraction Of The Wide-band Network Parameters And Transient Simulation Of The Secondary Cable In The Substation

As the electric power system voltage level increases and microelectronics equipment used in large amounts, Electromagnetic Compatibility (EMC) problems in the substation is serious. The electromagnetic environment numerical prediction is an effective method to solve this problem. And with this accurately measuring to electromagnetic interference in substation we can avoid buying expensive measuring equipments, and we can also save manpower, material and financial resources. As numerical calculation can be used repeatedly, we can make a deeper study about the electromagnetic interference. The numerical calculation in Electromagnetic interference prediction can sever for the engineering design directly, and we can make the designing purpose clearly by using this method.Based on the "Chinese Universities Scientific Fund" funded projects, the numerical calculation methods of the wide-band network parameters and transmission characteristics under lighting and VFTO of the secondary cable in the substation and the wide-band are studied in this paper. The secondary cable is regarded as transmission line, and its distribution parameters is calculated by finite element method (FEM) and analytical method. The secondary cable chain parameters (ABCD parameters)can be obtained by distribution parameters At last, we can obtain the its transfer function.Two kinds of the secondary cable, KVVP2-22 4×2.5mm~2 and KVVP2-22 8×1.5mm~2, are calculated. To improve the effectiveness of the computing methods, we measure the scatter parameters and time domain voltage by the Agilent 4395A network/impedance/spectrum analyzer and Agilent 33220A 20MHz signal generator,EMS61000-5A surge generator,GMY-1 Nanoseconds high-voltage pulsed sources respectively.In addition, to calculate the transmission interference, the cascaded two-port network transfer function is built in frequency domain. The vector-fitting method was used to approximate the transfer function. Then the output voltage of the secondary cable is directly calculated using recursive convolution. A comparison between the numerical results and the measured results of the output voltage confirms the correctness and effectiveness of the presented method.