Method for establishing three-phase short-circuit current correction curve of 380V power system

Abstract

The invention relates to electrical field and discloses a method for establishing a three-phase short-circuit current correction curve of a 380V power system. The method comprises: S1) computing resistance R and reactance X between the high-voltage side of a transformer and a short dot; S2) computing impedance Z between the high-voltage side of the transformer and the short dot according to the resistance R and the reactance X between the high-voltage side of the transformer and the short dot; S3) computing short-circuit current Id according to the impedance Z between the high-voltage side of the transformer and the short dot; and S4) establishing a three-phase short-circuit current correction curve according to a functional relationship between the length L of a cable from the initial end to the short dot and the short-circuit current Id. The three-phase short-circuit current correction curve established by the method is more accurate and the method contributes to more accurate computation of three-phase short-circuit current of the 380V power system for power system designers.

Description

technical field [0001] The invention relates to the electrical field, in particular to a method for establishing a three-phase short-circuit current correction curve in a 380V power system. Background technique [0002] In the power system design of power plants, the "380V power system three-phase short-circuit current curve" is a practical calculation tool, which reflects the different low-voltage plant transformers, Different cable types and lengths correspond to different three-phase short-circuit current values. In the previous power system design regulations and manuals, such as the "Power Engineering Electrical Design Manual (Electrical Primary Part)" published in 1989, and the "Technical Regulations for Power Design of Thermal Power Plants (DL / T5153-2002)" published in 2002 " and so on, have included this kind of curve. For a long time, power system designers have calculated the three-phase short-circuit current of the 380V system based on the above-mentioned regula...

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Problems solved by technology

However, the above regulations and manuals were compiled in the early period. At that time, there were few and small generator sets in the power system, and the corresponding short-circuit capacity of the power grid was also small, so the three-phase short-circuit current of the 380V system was relatively small.

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