Simulation And Experimental Research On Inductive Voltage And Inductive Current Of 500kV Common-tower Double-transmission Lines

In our country, the scope of power grid expands more and more giant, capabilities are also enhanced increasingly. 500kV system has been a backbone grid, which in order to reduce the ground of transmission porch; common-tower double-transmission lines will become a trend of high voltage power grid. With the emergence of common-tower double-transmission lines, investment will be undoubtedly reduced, which also brings new issues to the maintenance of lines. Therefore, the popularization and application of double-circuit tower have also become a very important topic in EHV power grid construction.When one of the common-tower double-transmission lines is running, the other one is in transit overhaul, overhaul line will be produced higher induced voltage and current, which will bring hurt to personnel and grounding switch. With the increase of voltage levels, switching electromagnetically inductive current and electrostatically inductive current are proposed. Operating conditions of inductive voltage and inductive current of common-tower double-transmission lines are demonstrated in this paper. To ensure the reliability and safety of the lines requested by earthing switch (ES) and disconnectors grounding of the equipment switch, a sensor must have a capacity of switching inductivecurrent.Inductive voltage and inductive current of 500kV common-tower double-transmission lines are analyzed in this paper. Inductive voltage and inductive current are verified by electromagnetism transient simulation software EMTP. J.Marti model is often used in transmission line models. It is a frequency dependent model with constant transformation matrix. Then the main factors that impact on ES of switching inductive current performance such as wire array, load, lines length, transposition and shunt reactor are proposed. From reality, the main technical parameters and principle of KZW1-50 outdoor vacuum switches are discussed. Siemens (Hang Zhou) BR5-550 ES switch inductive current's test datum and waveform maps are also given. It has practical significance for designing and choosing ES.