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Power transmission line harmonic parameter estimation method for power grid harmonic analysis

A transmission line and harmonic analysis technology, applied in the field of power system, can solve problems such as inaccurate parameter estimation, achieve the effects of simple calculation, small parameter estimation error, and engineering practicability

Active Publication Date: 2019-12-13
ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY
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Problems solved by technology

[0005] In order to solve the problem that the existing transmission line harmonic parameter estimation method ignores the frequency response of the unit impedance, resulting in inaccurate parameter estimation, a transmission line harmonic parameter estimation method for power grid harmonic analysis is proposed, which can estimate the transmission line more accurately Line Harmonic Parameters

Method used

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  • Power transmission line harmonic parameter estimation method for power grid harmonic analysis
  • Power transmission line harmonic parameter estimation method for power grid harmonic analysis
  • Power transmission line harmonic parameter estimation method for power grid harmonic analysis

Examples

Experimental program
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Effect test

Embodiment 1

[0087] Use PSCAD to simulate and verify a 500kV transmission line with a length of 300km. The parameter settings are shown in Table 1. The effective value of each equivalent harmonic voltage source at the sending end is set to 1% of the effective value of the fundamental voltage. The exact value of the harmonic parameters of the transmission line is extracted from the parameter file output by PSCAD. The simulation time is 24h, and the sampling interval is 5s, with a total of 17280 simulation data.

[0088] Table 1 Simulation model parameter settings

[0089]

[0090] The first step is to obtain the harmonic voltage, active power and reactive power values ​​at both ends of the transmission line. In this simulation case, the third harmonic voltage, active power and reactive power values ​​are as follows Figure 5 shown.

[0091] In the second step, the data is randomly sampled and grouped. The 10-minute sampling data is 120 points, and 10 points are randomly sampled as a gro...

Embodiment 2

[0098] The traditional harmonic parameter estimation of transmission lines ignores the equivalent parallel conductance. When there is corona loss in the transmission line, and considers the distributed parameter model (interaction among the four parameters), ignores the G 0 It may reduce the estimation accuracy of other parameters. Therefore, on the basis of Calculation Example 1, considering that there is a corona loss of 5kW / km (G 0 =0.0015), the calculation error is shown in Table 3.

[0099] Table 3 Example 2 calculation error

[0100]

[0101] It can be seen from Table 3 that the traditional method estimates the equivalent parallel resistance and conductance of the transmission line with large errors, and the calculation error of the equivalent conductance is high at all harmonic frequencies, while the calculation error of each parameter of the method proposed by Fangming All within 5%. It can be concluded that in the case of corona loss in the transmission line, th...

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Abstract

The invention discloses a power transmission line harmonic parameter estimation method for power grid harmonic analysis. The method comprises the steps that a power transmission line is monitored to obtain harmonic voltage effective values, harmonic active power and harmonic reactive power at the two ends; based on a power transmission line distribution parameter model, a relational expression between power transmission line harmonic parameters and the harmonic voltage effective values, the harmonic active power and the harmonic reactive power at the two ends is established; a plurality of point data is selected from each data segment, and an equation set is obtained by using multi-point estimation; and the equation set is solved through a nonlinear optimization algorithm to obtain harmonic parameters of the power transmission line. More accurate harmonic modeling is carried out by utilizing the harmonic parameters obtained by the method, and the method has significance in harmonic power flow calculation, state estimation, harmonic source positioning and the like of the power grid.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a method for estimating harmonic parameters of transmission lines used for harmonic analysis of power grids. Background technique [0002] As more and more nonlinear loads are connected to the power grid, the problem of harmonic pollution in the power grid is becoming more and more serious. It is of great significance to analyze the harmonics of the system, including harmonic power flow calculation, harmonic state estimation and harmonic source location. Harmonic modeling is carried out for each component of the system, and the estimation of its harmonic parameters is the premise of harmonic analysis. In recent years, the fundamental wave parameter identification technology of transmission lines has been relatively mature, but there are few related studies on harmonic parameter estimation. [0003] Traditional transmission line harmonic parameter estimation is based on the premise t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16G01R21/01G01R19/02
CPCG01R19/02G01R21/01G01R23/16
Inventor 徐群伟吴俊黄弘扬楼伯良吕文韬马智泉李培陈峰许双婷王杨
Owner ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY
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