Method for predicting inrush current of three-phase electric power transformer

A technology for three-phase transformers and exciting inrush currents, which is applied in the direction of measuring electrical variables, measuring electricity, instruments, etc., can solve the problems of cumbersome steps, inconvenient and accurate knowledge of the limit conditions of exciting inrush currents, and influence on accurate analysis of transformers, etc., to achieve the goal of easy and accurate analysis Effect

Active Publication Date: 2009-07-22
STATE GRID ZHEJIANG ELECTRIC POWER +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This new way reduces certain factors that affect how well an electric power system works by reducing its size while still maintaining good efficiency. It also simplifies calculations involving multiple components such as inductors and capacitors.

Problems solved by technology

This patented technical problem addressed in this patent relates to improving safety during power systems operations while minimizing damage caused due to excessive voltage surges that can occur when an electrical load connected across two different conductors becomes disconnected without being able to detect any significant changes over time. Current techniques involve estimating the amount of energy lost (involtages) associated with each section within the circuit before removing the affected sections. These estimates require precise measurements but they may also contain errors related to external factors such as temperature variations and manufacturing differences between components.

Method used

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  • Method for predicting inrush current of three-phase electric power transformer
  • Method for predicting inrush current of three-phase electric power transformer
  • Method for predicting inrush current of three-phase electric power transformer

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Embodiment Construction

[0025] physical models such as figure 2 , 3 The method for predicting the inrush current of the three-phase power transformer shown in 0 , establish a physical model parallel equation, the physical model contains a magnetic flux value φ 0 A zero-sequence flux loop with an imaginary current i 0 . Then change the voltage of each phase, the value of remanence and closing phase, and solve the equation to get the magnitude and waveform of the current value, so as to get the limit of the excitation inrush current.

[0026] In the figure, φ 1 , φ 2 , φ 3 are the magnetic fluxes of the three-phase magnetic flux circuits of A, B, and C, respectively, φ 0 Zero-sequence flux loop, φ 0 The value of is equivalent to φ in the existing method 4 +φ 5 +φ 6 value of . According to the model, the following equations can be obtained:

[0027] V A ...

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Abstract

The invention relates to the technical field of relay protection, in particular to a method for predicting excitation surge current of a three-phase power transformer. The defects of fussy steps, ,inconvenient knowing of the limit case of excitation surge current accurately and influence on accurate analysis of transformers exist in the prior art; in the invention, basic data acquisition, hypothesis amount phi0 setting and establishment of physical model coordinate equation are carried out in turn; the physical model comprises a zero sequence magnetic path having a magnetic flux value phi0; and the zero sequence magnetic path has a fictitious current i0. The voltage of each phase, magnetic remanence and value of switching phase are then changed; the equation is solved to obtain the current value and waveform, thereby obtaining the limit case of excitation surge current. Predicting and calculation processes are simplified by introducing zero sequence magnetic path and magnetic flux value phi0 thereof in the predicting process, thereby being capable of conveniently obtaining the limit case of excitation surge current and being propitious to accurate analysis of transformers.

Description

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Claims

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Application Information

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Owner STATE GRID ZHEJIANG ELECTRIC POWER
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