A Negative Sequence Impedance Parameter Estimation Method for Three-Phase Unbalanced Disturbance Source Location
A technology of disturbance source location and negative sequence impedance, applied in the measurement of resistance/reactance/impedance, instruments, measurement devices, etc., can solve the problems of system frequency change, asynchronous sampling data, etc., to filter out noise and avoid transient problems. Influence, sampling data process flexible and simple effect
Active Publication Date: 2018-01-19
STATE GRID CORP OF CHINA +2
View PDF5 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
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
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment
[0079] 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:
[0080] Such as image 3 As shown, the basic parameters of the system are:
[0081] Power supply system: 10kV, 50Hz, three-phase three-wire
[0082] System Impedance: Z Self =(0.4806+j2.5833)Ω, Z Mutual =(-0.2076+j0.1153)Ω
[0083] Transmission line: length 12km, line impedance matrix (per km) under A, B, C phase sequence is
[0084]
[0085] Load: The rated capacity of each phase is 5MVA
[0086] Record the three-phase voltage and current data of point P, the specific implementation steps are as follows:
[0087] Step 1: Collect the three-phase voltage and current data of point P, and the sampling frequency is 12.8kHz, that is, 256 points are sampled in each cycle;
[0088] Step 2: Fourier transform is performed on the collected three-phase voltage and...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More 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
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
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