Incoming current suppression device

A technology of inrush current suppression and three-phase AC, which is applied in circuit devices, emergency protection circuit devices, emergency protection circuit devices for limiting overcurrent/overvoltage, etc., and can solve large excitation inrush current, inconsistency between constant magnetic flux and residual magnetic flux, etc. problem, to achieve the effect of suppressing the excitation inrush current

Inactive Publication Date: 2009-04-22
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the state where there is a difference in the residual magnetic flux of the remaining two phases, if the remaining two phases are turned on at the above timing, the constant magnetic flux of the remaining phases does not coincide with the residual magnetic flux, causing a large inrush current to flow

Method used

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Examples

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Embodiment Construction

[0016] figure 1 It is a circuit block diagram of main parts of the power supply system according to one embodiment of the present invention. exist figure 1 In this current supply system, a three-phase circuit breaker 1 and a three-phase transformer 8 are provided. The three-phase circuit breaker 1 is a device for protecting the power supply system by cutting off the power supply when a certain accident occurs in the power supply system, and includes three switches 2 to 4 and three interelectrode capacitors 5 to 7 .

[0017] One terminal of the switches 2 to 4 respectively receives R-phase, S-phase and T-phase AC voltages from a three-phase AC power supply (not shown). The three switches 2 to 4 can be independently controlled respectively. During normal operation, switches 2 to 4 are closed for power supply. When some kind of accident occurs in the power supply system, the switches 2 to 4 are turned off to cut off the power supply.

[0018] The three interelectrode capac...

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PUM

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Abstract

A control unit 13 of an electric power supply system causes, responsive to a closing command signal phi B, a switch 2 corresponding to R phase to be thrown at a timing when a stationary magnetic flux and a residual magnetic flux of R phase are coincident with each other and then subsequently causes other switches 3, 4 corresponding to S phase and T phase to be thrown at a timing which is delayed from a zero point of an alternating voltage of R phase by a predetermined phase angle of 0-30 degrees, such that the difference of the stationary magnetic flux and the residual magnetic flux of each of S phase and T phase is minimum. Therefore, an exciting incoming current which flows into a three-phase transformer 8 at a time of throwing a three-phase breaker 1 provided with interpole capacitors 5-7 can be suppressed.

Description

[0001] technology area [0002] The invention relates to an inrush current suppression device, in particular to an inrush current suppression device for suppressing the excitation inrush current flowing into a three-phase transformer from a three-phase AC power supply through a three-phase circuit breaker. Background technique [0003] It is conventionally known that a transient current called a magnetizing inrush current flows from a three-phase AC power supply to a three-phase transformer when a three-phase circuit breaker is turned on. The excitation inrush current reaches several times to ten times the rated current of the three-phase transformer, resulting in the occurrence of situations such as an instantaneous drop of the three-phase AC voltage. [0004] As a suppression method for suppressing the magnetizing inrush current, there is a method in which the residual magnetic flux of each phase of the three-phase transformer is detected, and when the constant magnetic flu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01H33/59H01H9/56
CPCH02H9/002
Inventor 木下定之龟井健次森智仁伊藤弘基
Owner MITSUBISHI ELECTRIC CORP
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