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Voltage control method in power system with non-effectively earthed neutral

A voltage control method and non-effective grounding technology, applied in the direction of reducing the asymmetry of the multi-phase network, eliminating/reducing the asymmetry of the multi-phase network, etc., can solve the problem of the length of the three-phase line of the single-phase cable line, the influence of the system voltage quality, and the three-phase Phase unbalanced voltage and other problems, to achieve the effect of eliminating system unbalanced voltage, improving system voltage quality, and dynamically adjusting

Active Publication Date: 2012-10-17
SHANDONG KEHUI POWER AUTOMATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, distribution overhead lines generally do not transpose or seldom transpose, and single-phase cable lines also have three-phase line lengths and inconsistent models. These problems will cause three-phase unbalanced voltage
When the unbalanced voltage of the system is large, it will affect the voltage quality of the system, and in severe cases, a virtual ground fault will occur

Method used

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  • Voltage control method in power system with non-effectively earthed neutral
  • Voltage control method in power system with non-effectively earthed neutral
  • Voltage control method in power system with non-effectively earthed neutral

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] 1. System voltage recovery control after small current grounding fault arc extinguishing

[0069] For non-effectively grounded systems, the content of the present invention can suppress the recovery degree and recovery speed of the three-phase voltage and zero-sequence voltage after the arc is extinguished at the small current ground fault point, and provide sufficient recovery time for the arc insulation at the fault point, thereby reducing the arc heavy Increase the probability of ignition and improve the self-recovery (self-healing) level of single-phase ground faults.

[0070] Its implementation steps are as follows:

[0071] (1) Determine the power frequency current injection equipment

[0072] The current injection device can be a pure all-power electronic device, or a hybrid device that combines traditional arc suppressing coil 2 with power electronics.

[0073] (2) Determine how the power frequency current injection equipment is connected to the system

[007...

Embodiment 2

[0083] 2. Eliminate the three-phase unbalanced voltage of the system during normal operation

[0084] For non-effectively grounded systems, when the parameters of the three-phase line are unbalanced with respect to the ground, voltage unbalance and zero-sequence voltage can be caused. Utilizing the contents of the invention can eliminate this type of unbalanced voltage and improve power quality.

[0085] This example can share the same device platform as the system voltage recovery control after ground fault arc extinction.

[0086] Its implementation steps are as follows:

[0087] (1) Determine the power frequency current injection equipment

[0088] The current injection device can be a pure all-power electronic device, or a hybrid device that combines traditional arc suppression coils with power electronics.

[0089] (2). Determine how the power frequency current injection equipment is connected to the system

[0090] According to the system structure, the current injec...

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Abstract

The invention relates to a voltage control method in a power system with a non-effectively earthed neutral. Power current with adjustable amplitude value and phase position is injected in a system neutral, and three phases of voltage to earth and zero sequence voltage of the system are adjusted and controlled. The recovery degree and the recovery speed of the three phases of voltage and the zero sequence voltage can be delayed by the technology after the arc blowout of a small current grounding fault point, and enough time is provided for the insulation recovery of the fault point, so that the restriking probability is reduced, and the self-recovery (self-healing) probability of fault is improved. When the system is in normal operation, unbalanced voltage caused by the imbalance of the three phases of parameters to earth such as untransposition of circuits or incomplete transposition of the circuits is eliminated. The technology can be realized by an independent device, and also can be realized by an active compensation device platform for full electrical capacity compensation in a small current grounding fault. The voltage control method in the power system with the non-effectively earthed neutral disclosed by the invention is used as a main technical measure of a smart distribution grid, and the power quality and the self-healing level of the fault of a medium voltage distribution grid can be observably improved.

Description

technical field [0001] The invention relates to a voltage control method in a neutral point non-effectively grounded power system. The invention relates to a non-effectively grounded (neutral point not grounded, grounded through an arc-suppression coil, high-impedance grounded or full electric quantity compensation active grounded, etc.) power system Three-phase-to-ground voltage and zero-sequence voltage adjustment and control methods. [0002] The invention particularly relates to a method for adjusting and controlling the recovery degree and recovery speed of the system voltage after the single-phase ground fault point arc extinguishes in the non-effectively grounded power system. [0003] In particular, the invention relates to a method for adjusting and controlling unbalanced voltage caused by unbalanced line-to-ground parameters during normal operation in a non-effectively grounded power system. Background technique [0004] The neutral point of my country's 10-66kV m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/26
CPCY02E40/50
Inventor 薛永端徐丙垠
Owner SHANDONG KEHUI POWER AUTOMATION
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