Disturbance area negative-sequence current judgment method

A negative-sequence current and load modeling technology, applied in the electric power field, can solve problems such as faults that cannot be divided into areas or faults outside the area, and achieve the effect of simple and accurate judgment methods and accurate judgments.

Inactive Publication Date: 2012-06-20
领步科技集团有限公司
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Problems solved by technology

[0005] In view of the above-mentioned shortcomings in the prior art that the load modeling cannot distinguish between faults in the region or faults outside the region, the present invention provides a new method for judging the negative sequence current in the disturbance region for load modeling, which is A method for judging the direction of the fault source based on measurement data is proposed for the data validity analysis requirements of the overall measurement and identification method load modeling

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[0014] This embodiment is a preferred implementation mode of the present invention, and other principles and basic structures that are the same or similar to this embodiment are within the protection scope of the present invention.

[0015] Please see attached figure 1 And attached figure 2 , in the present invention, the source of the required measurement data is the power quality online monitoring device. These devices are generally installed at the busbar end of the incoming line in the load area. Assume that the busbar at the installation place of the detection device is A, and the power grid system at the front end of busbar A uses a The power supply is equivalent to a bus B, and the load area behind the bus A is equivalent to a bus C and a power supply. Among them, the monitoring device can monitor the three-phase voltage and current flowing out of bus A in real time, and record its instantaneous value. In this embodiment, the sampling frequency of the monitoring devic...

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Abstract

A disturbance area negative-sequence current judgment method used for load modeling includes steps as follows: A. three-phase voltage and current flown out from a bus are collected in real time by a monitoring device, each instantaneous value is recorded, voltage and current instantaneous values collected on site when a fault occurs are subjected to Fourier filtering according to Fourier transform, and fundamental wave components of the voltage and current instantaneous values are obtained; B. the symmetrical component method is applied to the fundamental wave voltage and current, and voltage and current negative-sequence components are extracted; and C. the voltage and current phase relation is solved according to the voltage and current negative-sequence components, if the measured negative-sequence current exceeds the negative-sequence voltage for an angle of Pi-Theta (Theta is the impedance angle of the impedance of a system in front of the monitoring device), when Theta is larger than or equal to 0 and smaller than or equal to Pi / 2, the fault occurs inside the area; and if the measured negative-sequence current falls behind the negative-sequence voltage for an angle of Theta1 (Theta1 is the impedance angle of the impedance of the load behind the monitoring device), when Theta1 is larger than or equal to 0 and smaller than or equal to Pi / 2, the fault occurs outside the area.

Description

technical field [0001] The invention discloses a negative-sequence current judgment method, specifically a negative-sequence current detection method for valid judgment of disturbance data in load modeling, and belongs to the field of electric power technology. Background technique [0002] A lot of research work has been carried out in the field of load modeling at home and abroad, and many methods have been proposed. Among them, the "overall measurement and identification method" has the advantages of not needing to know the specific components of the load, and the field measured data can reflect the actual characteristics of the load. , is widely used in load modeling work in our country. [0003] However, the data obtained by the overall measurement and identification method mainly depends on the data recording device specially developed for load model identification. Due to the problems of single function, high cost, inconvenient installation, and difficult operation an...

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Application Information

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IPC IPC(8): G01R31/08G01R19/00
Inventor 邹正华唐新红向阳夏锐熊耀明
Owner 领步科技集团有限公司
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