A 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 the problem of inaccurate parameter estimation, and achieve the effect of simple calculation and small parameter estimation error.

Active Publication Date: 2021-11-09
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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  • A transmission line harmonic parameter estimation method for power grid harmonic analysis
  • A transmission line harmonic parameter estimation method for power grid harmonic analysis
  • A transmission line harmonic parameter estimation method for power grid harmonic analysis

Examples

Experimental program
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Effect test

Embodiment 1

[0086] 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.

[0087] Table 1 Simulation model parameter settings

[0088]

[0089] 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.

[0090] 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

[0097] 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 the corona loss of the transmission line is 5kW / km (G 0 =0.0015), the calculation error is shown in Table 3,

[0098] Table 3 Embodiment 2 calculation error

[0099]

[0100] It can be seen from Table 3 that the traditional method estimates the equivalent parallel resistance and conductance of the transmission line with relatively large errors, and the calculation errors of the equivalent conductance at all harmonic frequencies are relatively high, while the calculation errors of each parameter of the method proposed by the present invention are all large. Within 5%. It can be concl...

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Abstract

The invention discloses a method for estimating harmonic parameters of a power transmission line for harmonic analysis of a power grid. The line distribution parameter model establishes the relationship between the harmonic parameters of the transmission line and the effective value of the harmonic voltage at both ends, the harmonic active power and the harmonic reactive power; randomly select more than one for each data segment Point data, using multi-point estimation to obtain a system of equations; solving the system of equations through a nonlinear optimization algorithm to obtain harmonic parameters of the transmission line. Using the harmonic parameters obtained in the present invention to carry out more accurate harmonic modeling is of great significance for power grid harmonic power flow calculation, state estimation, harmonic source positioning and the like.

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 Patents(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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