Study on the characteristics of the potential rise of shell under VFTO in the GIS pumped storage power station

Abstract

Compared with the traditional GIS station, complex wiring and operation mode of pumped-storage plant diversity, working condition of frequent transformation, makes the plant to produce very fast transient overvoltage (VFTO) probability increase greatly. VFTO will form a transient coupled to the GIS shell casing transient earth voltage (TEV), and then to station personnel safety and the reliability of the secondary equipment poses a great threat. But at the moment because of the limitation of testing technology such as understanding of the academic study of TEV is lack of system. Based on a typical 500 kV gis pumped-storage power station, this paper established a system equivalent model of GIS, network frame and calculates the amplitude, frequency spectrum characteristic of the TEV and influence on VFTO characteristics, and analyzes the fault location, power supply mode, branch bus, the influence of vertical grounding electrodes on the TEV characteristics, For the characteristics of the TEV rules and parameters. Research on TEV characteristics of GIS of pumped storage power station has important reference value for further perfecting relevant theories.

Measurement study of UHF local discharge based on voltage division method

“…The wiring connecting the measured impedance and the amplification unit in the measuring instrument, usually shielded coaxial cable, etc. According to the interference situation during the test, the test loop is connected with a low-pass filter Zf to reduce the interference from the power supply and appropriately improve the minimum measurable level of the measurement loop [11].…”