Research On Disturbance Analysis And Protective Measures Of Switch Operation On Secondary Equipment

With the continuous increase of voltage and capacity of high voltage grid,electromagnetic compatibility in substation is complicated.In the process of power system operation,when an the switch points might sex small current,the transient over-voltage operation(very fast transient over-voltage,VFTO),it can be up to several times the rated voltage amplitude and the frequency of up to tens of megahertz,such a system of fast transient harassment will be linked together through capacitive voltage divider conduction to the secondary system,causes the weak current in the secondary system equipment acquisition data is abnormal,even under extremely complicated conditions can lead to secondary equipment damage,and thus have a more serious system chain problems.This article in view of the present research situation,mainly study the switch points might by small current operation when the fast transient disturbance to the influence of the electronic instrument transformer internal circuit,based on the transient disturbance test results and the experimental system of broadband characteristics,through the comparison of system side-load side voltage,puts forward the points and closing operation of the main charge and discharge circuit,and presents a series of the calculation method of breakdown point in time.The equivalent circuit model of the experimental platform for the system's new substation pulse-close test is established by using the method of piece-wise linear source control ideal switch,and the maximum disturbance of the system is analyzed by using the simulation method,and the disturbance characteristics of the electronic transformer port circuit are further tested and simulated.According to the measurement of common mode choke coil terminal between broadband impedance characteristics,extracting the basic equivalent circuit parameters,the power function of the inductance of the frequency characteristics is described,and the establishment of a common mode choke coil circuit simulation model,and in order to optimize the filtering performance of EMI filter,in the common mode choke coil,on the basis of the equivalent circuit model,combined with the rest of the components of the EMI filter broadband impedance equivalent circuit,the single-stage EMI filter circuit model was established,the simulation analysis of the common mode and differential mode of transmission characteristics.