Direct-current magnetic bias suppression method used during single-pole running of direct-current system

A DC bias suppression and DC system technology, applied in the direction of emergency protection circuit devices, electrical components, emergency protection circuit devices, etc. for limiting overcurrent/overvoltage, can solve hazards, influence of normal operation of power systems, capacitor banks Problems such as overload

Inactive Publication Date: 2015-07-01
HENAN XINGZHI PATENT SERVICE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

While there is some awareness of the negative impact of DC single pole ground circuit operation, incidents of transformer vibration intensification have shown that this 'effect' is greater than expected
From the field monitoring data, it can be known that the vibration noise and harmonics of the transformer increase with the increase of the neutral point DC current. When there is a DC bias current in the power grid, the normal operation of the power system will be greatly affected and harm
It is easy to cause the voltage drop of the power system; the capacitor bank is overloaded; the relay protection malfunctions; the power system and the transformer suffer a certain degree of damage

Method used

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  • Direct-current magnetic bias suppression method used during single-pole running of direct-current system
  • Direct-current magnetic bias suppression method used during single-pole running of direct-current system
  • Direct-current magnetic bias suppression method used during single-pole running of direct-current system

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Embodiment Construction

[0055] A method for suppressing DC bias magnetic field during unipolar operation of a DC system. Through the analysis of the phenomenon of DC magnetic bias, the calculation of the equivalent impedance between the DC ground pole and the ground point of the AC transformer, and the analysis and solution of the transformer model, the DC monopolar DC bias during pole operation.

[0056] Such as figure 1 As shown in Fig. 1, under the single-pole return operation mode of the DC transmission system, the ground is equivalent to a conductor of the DC transmission, and the current flowing is the operating current of the DC transmission system, which will cause a large change in the surface potential near the converter station , so that the surrounding neutral point grounding transformer generates a DC component at the neutral point. Among them, the DC current components flowing through the two neutral-point grounded transformers depend on the potential of the two transformers, the groun...

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Abstract

The invention provides a direct-current magnetic bias suppression method used during single-pole running of a direct-current system. A direct-current magnetic bias generating mechanism generated by a transformer and grounding resistance are calculated during single-pole running of the direct-current system and a transformer model is analyzed to obtain simulation data of single-pole running of the direct-current system, and direct-current magnetic bias generated in single-pole running of the direct-current system is restrained.

Description

technical field [0001] The invention relates to the technical field of direct current transmission, in particular to a method for suppressing direct current bias magnetic field during unipolar operation of a direct current system. Background technique [0002] When the system is commissioned, overhauled or fails, the UHVDC will operate with a single pole, and a DC current may be generated in the grounding transformer. The transformer is injected into the transformer through the neutral point of the transformer, so that the iron core of the transformer is magnetized by DC, and the magnetic operating point is shifted, causing the unidirectional saturation of the iron core and causing DC bias. DC bias will generate harmonics in the excitation current of the transformer, and the influx of harmonics into the system will cause system voltage waveform distortion, relay protection device malfunction and other hazards. [0003] DC bias is the main reason for the aggravation of trans...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): H02H9/02
Inventor马新攀
OwnerHENAN XINGZHI PATENT SERVICE CO LTD