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Harmonic elimination method, system and device

A harmonic elimination and harmonic elimination technology, applied in the field of distribution network, can solve the problems of voltage transformer fusing, voltage transformer body damage, etc., and achieve the effect of suppressing resonance

Inactive Publication Date: 2021-02-05
STATE GRID BEIJING ELECTRIC POWER +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The embodiment of the present application provides a harmonic elimination method, system and device to at least solve the problem that low-frequency nonlinear oscillations are prone to occur in the voltage transformer when a single-phase ground fault is restored, and a large overcurrent will appear on the high-voltage side, resulting in The technical problem that the fuse of the voltage transformer is blown or even the body of the voltage transformer is damaged

Method used

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  • Harmonic elimination method, system and device

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Embodiment 1

[0029] According to an embodiment of the present application, an embodiment of a harmonic elimination method is provided. It should be noted that the steps shown in the flow chart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and, Although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in an order different from that shown or described herein.

[0030] In the power system, the principle of low-frequency nonlinear oscillation is: when a single-phase ground fault occurs in the 10kV system (taking phase A as an example), the current flowing through the ground point is:

[0031]

[0032] where C 11 is the line-to-ground capacitance, and L is the primary winding inductance of the voltage transformer. E. m is the electromotive force amplitude, then the A-phase electromotive force E a The instantaneous value expression of is:

[0033]

[0034] The ...

Embodiment 2

[0068] According to the embodiment of the present application, a harmonic elimination system is also provided. As shown in FIG. 4, the system includes at least a three-phase voltage transformer 40, a non-linear resistance harmonic elimination damping device 42 and three remaining windings 44, wherein:

[0069] Three-phase voltage transformer 40, wherein each single-phase voltage transformer is provided with a residual winding, and the remaining winding is used to generate residual voltage when a single-phase ground fault occurs;

[0070] The nonlinear resistance harmonic elimination damping device 42 is connected to the three-phase voltage transformer, wherein the neutral point of the primary side winding of the three-phase voltage transformer is connected to the ground through the nonlinear resistance harmonic elimination damping device;

[0071] The three remaining windings 44 are used for short-circuiting to form a delta winding with an opening, and the voltage at both ends ...

Embodiment 3

[0078] According to the embodiment of the present application, a harmonic elimination device is also provided, such as Figure 5a As shown, the device at least includes a first processing module 50, a second processing module 52 and a third processing module 54, wherein:

[0079] The first processing module 50 is used to connect the neutral point of the primary side winding of the three-phase voltage transformer to the ground through the non-linear resistance harmonic elimination damping device;

[0080] The second processing module 52 is used to short-circuit the remaining windings on the secondary side of the three-phase voltage transformer to form a delta winding with an opening, wherein each single-phase voltage transformer is provided with a remaining winding, and the remaining winding is used when a single-phase voltage transformer occurs. Residual voltage is generated in case of phase-to-ground fault;

[0081] The third processing module 54 is configured to connect the...

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PUM

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Abstract

The invention discloses a harmonic elimination method, system and device. The method comprises the steps that a neutral point of a primary side winding of a three-phase voltage transformer is connected with the ground through a nonlinear resistance harmonic elimination damping device; the residual windings on the secondary sides of the three-phase voltage transformer are short-circuited to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase earth fault occurs; and when a single-phase earth fault is detected, the two ends of the opening of the triangular winding are connected with the opening through a target resistor. The voltage transformer solves the technical problems that when the single-phase earth fault is recovered, low-frequency nonlinear oscillation is likely to occur in the voltage transformer, and great overcurrent occurs on the high-voltage side of the voltage transformer, so that the fuse of the voltage transformer is fused, and even the voltage transformer body is damaged.

Description

technical field [0001] The present application relates to the field of distribution network technology, in particular, to a harmonic elimination method, system and device. Background technique [0002] When there is a large capacitive current in the neutral point ungrounded system of the distribution network, a high-voltage fuse blown accident of a potential transformer (PT) is prone to occur at the moment when the single-phase ground is restored. When the single-phase fuse of the PT primary side high-voltage fuse is blown, it can cause false grounding of the system, and the voltage of the open triangle will increase, causing the relay to malfunction. [0003] The main reason for the frequent fusing of PT fuses is the overcurrent caused by overvoltage. In the neutral point non-effectively grounded system, the overvoltages that are more threatening mainly include lightning overvoltage, operating overvoltage, ferromagnetic resonance overvoltage and low-frequency nonlinear osc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H9/00
CPCH02H9/007
Inventor 王智晖桂媛徐兴全姚玉海杨亚奇
Owner STATE GRID BEIJING ELECTRIC POWER