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Negative sequence impedance parameter estimation method for locating three-phase unbalanced disturbance source

A disturbance source location, negative sequence impedance technology, applied in the measurement of resistance/reactance/impedance, instruments, measuring devices, etc., can solve the problem of sampling data asynchrony, system frequency change, etc.

Active Publication Date: 2015-01-28
STATE GRID CORP OF CHINA +2
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Problems solved by technology

Most of the existing impedance estimation methods are aimed at harmonic sources, and are analyzed and studied under the assumption that the three-phase system is symmetrical, and the proposed method is often subject to problems such as sampling data out of sync and system frequency changes in practical applications. Impact

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  • Negative sequence impedance parameter estimation method for locating three-phase unbalanced disturbance source
  • Negative sequence impedance parameter estimation method for locating three-phase unbalanced disturbance source
  • Negative sequence impedance parameter estimation method for locating three-phase unbalanced disturbance source

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Embodiment

[0078] The present invention provides a method for estimating negative-sequence impedance parameters for the location of three-phase unbalanced disturbance sources. The specific implementation methods are as follows:

[0079] Such as image 3 As shown, the basic parameters of the system are:

[0080] Power supply system: 10kV, 50Hz, three-phase three-wire

[0081] System Impedance: Z Self =(0.4806+j2.5833)Ω, Z Mutual =(-0.2076+j0.1153)Ω

[0082] Transmission line: length 12km, line impedance matrix (per km) under A, B, C phase sequence is

[0083] Z abc = 0.3959 + j 0.9122 0.0581 + j 0.4934 0.0581 + j 0.4934 ...

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Abstract

The invention relates to a negative sequence impedance parameter estimation method for locating a three-phase unbalanced disturbance source. The method comprises the steps that (1) measuring data are collected; (2) a multi-moment KVL equation is built; (3) sampling data unchanged on a system side are selected based on a three-point method; (4) sampling data with fluctuation on a load side are selected based on the load fluctuation rate; (5) an objective function is built to solve system negative sequence equivalent impedance parameters. According to the method, based on PCC multi-moment voltage and current sampling data, negative sequence impedance is estimated by solving the multi-moment KVL equation, the sampling data do not need to be synchronized, the influence of system frequency changes is avoided, and compared with a method with the sampling data needing to be synchronized, the data sampling process is more flexible and convenient. Data with the fluctuation on the load side and the unchanged system side can be effectively selected based on the three-point method, data in the load fluctuation process are extracted through the method based on the load fluctuation rate, noise can be effectively filtered out, the influence of the transient state is avoided, and estimation errors are reduced.

Description

technical field [0001] The invention relates to a method for estimating negative sequence impedance parameters, in particular to a method for estimating negative sequence impedance parameters for locating three-phase unbalanced disturbance sources. Background technique [0002] The power quality problem at the point of common connection (PCC) of the power supply system is the result of the interaction between the power supply and the consumer, and the power consumer also includes some unknown loads. When the power quality of PCC exceeds the limit value specified in the standard, it is difficult to distinguish the respective responsibilities of the power company and the user equipment for the inferior power at PCC. In order to solve this problem, a large number of researches on the location of power quality disturbance source and power quality responsibility assessment have been carried out at home and abroad, especially a lot of in-depth research on the problem of harmonic s...

Claims

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Application Information

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IPC IPC(8): G01R27/02
Inventor 刘颖英王同勋渠通孙媛媛李培鑫
Owner STATE GRID CORP OF CHINA