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Anti-excitation current electromagnetic voltage transformer

A technology for electromagnetic transformers and voltage transformers, applied in electrical components, emergency protection circuit devices, etc., can solve the problems of insufficient technology and quality, enlarged iron core area, inaccurate measurement characteristics, etc., to enhance system stability stability, reliable design principle, and the effect of wide application prospects

Inactive Publication Date: 2020-02-21
国网山东省电力公司潍坊市寒亭区供电公司 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the complexity and randomness of the ferromagnetic resonance phenomenon make these three suppression measures have certain limitations and scope of application.
① The method improves the excitation characteristics by increasing the cross-sectional area of ​​the iron core or the number of turns of the high-voltage coil. However, if the iron core is too large, it will take up too much space, and increasing the iron core area cannot ensure the stability of the arc grounding; Coil turns, also makes the measurement characteristics imprecise
②Although the method can quickly suppress ferromagnetic resonance in theoretical simulation, in practical applications, due to poor technology and quality, the effect of the resonance eliminator is poor
③ method At the moment of single-phase grounding and elimination of ferromagnetic resonance, high potential will appear on the resistance, which is not applicable to electromagnetic voltage transformers with weak insulation at the neutral point

Method used

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Embodiment 1

[0023] This embodiment provides an electromagnetic voltage transformer with anti-excitation current, which can reduce the number of blown high-voltage fuses of the electromagnetic voltage transformer. refer to figure 1 , connect the resonance elimination resistor in parallel at the opening triangle of the electromagnetic voltage transformer.

[0024] The harmonic elimination resistor is connected to the opening triangle of the electromagnetic voltage transformer, which is equivalent to the parallel resistance R on the high voltage side connection line of the electromagnetic voltage transformer Δ ,Down figure 1 middle, E A ,E B ,E C is the three-phase symmetrical power electromotive force of A, B, C, L is the three-phase excitation inductance of the electromagnetic voltage transformer, C 0 It is the ground capacitance of the three-phase line and the bus bar. During normal operation, the resistance R Δ It doesn't work. Once the zero-sequence voltage appears in the winding ...

Embodiment 2

[0039] This embodiment provides an electromagnetic voltage transformer with anti-excitation current, and a harmonic elimination resistor is connected in parallel at the open triangle of the electromagnetic transformer. In addition, an electric switch is provided on the parallel branch road, the electric switch is connected to the controller, and the controller controls the closing and opening of the electric switch. The controller monitors the fault information of the electromagnetic transformer, and once it detects that the fault is eliminated, it immediately controls the electric switch to close at the moment of removal. In the power system, the most frequent fault is single-phase grounding. Connecting the resonance elimination resistor at the open triangle at the instant the fault disappears has a good effect on suppressing the ferromagnetic resonance excited by the disappearance of the single-phase ground fault. The installation of electric switches and controllers furthe...

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Abstract

The invention provides an anti-excitation current electromagnetic voltage transformer, which is characterized in that a resonance elimination resistor is connected in parallel at an opening triangle of the electromagnetic voltage transformer, so that the resonance elimination resistor cannot be connected under the conditions that the system operates normally and that faults such as single-phase grounding occurs and resonance does not occur; and the resonance elimination resistor is connected when the grounding fault of the system disappears and resonance is instantly caused, and the resonanceelimination resistor consumes energy at the moment, so that the resonance energy is released. According to the invention, the ferromagnetic resonance of the electromagnetic voltage transformer can besuppressed under the conditions of no power failure, small investment and safe construction, the fusing frequency of a high-voltage fuse is reduced, and the system stability is enhanced.

Description

technical field [0001] The invention relates to the technical field of electromagnetic voltage transformers, in particular to an electromagnetic voltage transformer resistant to excitation current. Background technique [0002] In the 10kV neutral point ungrounded system, electromagnetic voltage transformers are widely used. When the circuit breaker is switched or a fault causes an electromagnetic transient process, the electromagnetic voltage transformer enters a saturated state from the normal working state. When the electromagnetic voltage transformer When the inductance parameters of the voltage transformer match the capacitance parameters in the system, ferromagnetic resonance will occur, causing the electromagnetic voltage transformer to over-excite, causing the excitation current to increase sharply, and the fuse of the high-voltage fuse to blow, causing the power grid to run And metering devices cannot be detected, seriously affecting the safe and stable operation of...

Claims

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Application Information

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IPC IPC(8): H02H7/05
CPCH02H7/05
Inventor 马慧韩洪泽李丽明孙刚冯光涛孟国栋祝明
Owner 国网山东省电力公司潍坊市寒亭区供电公司