Potential transformer electromagnetic transient modeling and analysis method of VFTO (very fast transient overvoltage) analysis of GIS (gas insulated switchgear) substation

Abstract

The invention discloses a potential transformer electromagnetic transient modeling and analysis method of the VFTO (very fast transient overvoltage) analysis of a GIS (gas insulated switchgear) substation. The method includes the following steps that: step 1, a PSCAD / EMTDC software customization function is adopted to complete the construction of a bus-bar potential transformer electromagnetic transient model; step 2, based on a principle that the bus-bar potential transformer electromagnetic transient model is converted into a downwards-turned-L type equivalent circuit through using a single-phase transformer T type equivalent circuit, so that a transformer transfer function is constructed, and megahertz-level high-frequency signals introduced to a primary side can be coupled to a cable core at a secondary side; and step 3, the bus-bar potential transformer electromagnetic transient model simulates the saturation characteristic of the transformer through a current and voltage characteristic curve table. With the potential transformer electromagnetic transient modeling and analysis method of the VFTO (very fast transient overvoltage) analysis of the GIS (gas insulated switchgear) substation of the invention adopted, problems such as little research on high-frequency over-voltage hazards of the secondary side of the potential transformer (PT) of a GIS (gas insulated switchgear) substation and the lack of corresponding simulation models can be solved.

Description

technical field [0001] The invention belongs to the overvoltage analysis and modeling technology in the field of electrical engineering, in particular to a voltage transformer electromagnetic transient modeling method for GIS substation VFTO analysis. Background technique [0002] Gas insulated switchgear (GIS) has the advantages of compact structure, small footprint, and easy maintenance. It has been widely used in 110kV and above power grids, and GIS equipment is increasingly used in high-voltage AC transmission systems. In GIS substations, the operation of circuit breakers, disconnectors and grounding switches, as well as the occurrence of single-phase-to-ground short-circuit faults will all generate very fast transient overvoltage (VFTO), among which the operation of disconnectors is the main reason. VFTO has the characteristics of high amplitude, steep wave front, high frequency and multiple continuous pulses, which has an important impact on the insulation of GIS and i...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a method for modeling and analyzing the electromagnetic transient state of voltage transformers in GIS substation VFTO analysis, so as to solve the problem of high-frequency overvoltage on the secondary side of voltage transformers (Potential Transformer, PT) in GIS substations in the prior art. There are few studies on voltage hazards and the lack of corresponding simulation models

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