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DC resistance selection method and system for complex power distribution network comprehensive optimization device

A technology of DC resistance and optimization device, applied in the field of flexible distribution network, can solve the problems of inaccurate line selection, false alarm, and increase the difficulty of fault line selection.

Active Publication Date: 2018-06-05
ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the compensation effect of the arc suppression coil, the characteristics of the zero-sequence current of the fault line and the non-fault line may be the same in the steady state, which greatly increases the difficulty of fault line selection, resulting in inaccurate line selection and false alarms.
At the same time, the traditional arc suppression coil grounding method cannot automatically and continuously follow the changes of the grid parameters for optimal adjustment, and cannot keep the residual current at the fault point at a minimum state at any time

Method used

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  • DC resistance selection method and system for complex power distribution network comprehensive optimization device
  • DC resistance selection method and system for complex power distribution network comprehensive optimization device
  • DC resistance selection method and system for complex power distribution network comprehensive optimization device

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Embodiment 1

[0058] This embodiment provides a method for selecting DC resistance of a comprehensive optimization device for a complex distribution network.

[0059] Such as figure 1 As shown, the comprehensive optimization device uses a transformerless hybrid MMC (MMC is a type of voltage source converter). The AC side of the hybrid MMC is directly connected to the substation bus through an AC circuit breaker Q, and there is no connecting transformer in the middle; Positive side and capacitor C 1 Connected, the negative pole of the DC side is connected to the capacitor C 2 Connected, capacitance C 1 The other end of the capacitor C 2 Is connected to the other end, and at the same time with the DC resistance R 0 Connected, DC resistance R 0 The other end is directly grounded.

[0060] The hybrid MMC adopts a three-phase six-arm structure. Each bridge arm is composed of n sub-modules cascaded and connected in series with bridge-arm reactors. Among them, the number of sub-modules n consists of DC...

Embodiment 2

[0127] This embodiment provides a DC resistance selection system of a comprehensive optimization device for a complex distribution network. The comprehensive optimization device for the complex distribution network is a transformerless hybrid MMC. The AC side of the hybrid MMC is directly connected to the substation bus through an AC circuit breaker, and there is no connecting transformer in the middle; the positive pole of the DC side is connected to the capacitor C 1 Connected, the negative pole of the DC side is connected to the capacitor C 2 Connected, capacitance C 1 The other end of the capacitor C 2 Is connected to the other end, and at the same time with the DC resistance R 0 Connected, DC resistance R 0 The other end is directly grounded. Each bridge arm of the hybrid MMC is composed of multiple sub-modules cascaded and connected in series with bridge arm reactors. There are two types of sub-modules in the bridge arm, HBSM and FBSM, and the ratio of the two types of sub-...

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Abstract

The invention discloses a DC resistance selection method and system for a complex power distribution network comprehensive optimization device. The DC resistance selection method comprises the following steps: 1) constructing positive-sequence, negative-sequence and zero-sequence three-sequence fundamental frequency equivalent circuits and equivalent circuits at a sampling frequency for the complex power distribution network comprehensive optimization device; 2) constructing positive-sequence, negative-sequence and zero-sequence three-sequence equivalent circuits at a fundamental frequency anda sampling frequency of a power distribution system at a fault point; 3) calculating to obtain a relationship between fault current and DC resistance; 4) determining a lower limit value of the DC resistance; 5) calculating to obtain a relationship between the current of the sampling frequency at the fault point and the DC resistance; 6) determining an upper limit value of the DC resistance; and 7) obtaining the DC resistance according to the lower limit value and the upper limit value as well as a relationship between the lower limit value and the upper limit value. The DC resistance selection method and system disclosed by the invention have the benefits that a selected DC resistance value can take into account effective arc suppression and accurate line selection of the power distribution system, effectively improve the control performance of the comprehensive optimization device and realize the substitution effect on an arc suppression coil.

Description

Technical field [0001] The invention belongs to the technical field of flexible distribution networks, and specifically relates to a DC resistance selection method and system of a comprehensive optimization device for a complex distribution network. Background technique [0002] In recent years, many new electrical equipment based on power electronic technology have appeared in the power supply and distribution system. These nonlinear loads have nonlinear and impact characteristics, which not only cause the distortion of the bus voltage and current waveforms in the system, but also lead to The flicker, fluctuation and three-phase imbalance of the power grid bus voltage have caused serious pollution to the power supply quality and affected the economic and safe operation of electrical equipment in the power grid. Voltage source converters have excellent control and operation performance, and have been widely used as active filters, reactive power compensators, etc., to optimize po...

Claims

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Application Information

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IPC IPC(8): G01R27/02G01R31/02
CPCG01R27/02G01R31/50
Inventor 许烽陆翌裘鹏宣佳卓陈骞倪晓军丁超王朝亮
Owner ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY
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