Three-phase imbalance source tracing method based on dynamic programming time series similarity

Abstract

The invention relates to a method for tracing the source of three-phase imbalance based on the similarity of dynamic programming time series. Obtain the negative sequence voltage monitoring data collected by the power quality monitoring terminal installed on the bus from the power quality monitoring system within a preset time, and form negative sequence voltage time series data; obtain all the power supplies supplied by the bus from the power consumption information collection system Active power data within the user preset time, and form active power time series data; use data standardization method to process negative sequence voltage monitoring data and active power data, and form negative sequence voltage and active power standardization Time series data; use the algorithm based on the principle of dynamic programming to solve the similarity of time series data to solve the correlation between the time series data of active power consumption of each user and the time series data of negative sequence voltage on the bus, and trace the source of three-phase imbalance. The method of the invention can analyze the correlation between the average active power sequence data of each user and the negative sequence voltage sequence data, and determine that the user with the strongest correlation is a three-phase unbalanced source.

Description

technical field [0001] The invention relates to a method for tracing the source of three-phase imbalance based on the similarity of dynamic programming time series. Background technique [0002] With the acceleration of the development trend of modern industry, the three-phase unbalanced load in the power grid is also increasing, which makes the three-phase unbalanced problem of the public power grid more and more serious. The negative sequence components contained in the voltage and current will cause many Adverse effects, such as increasing the loss of line power, reducing the efficiency of distribution transformers, causing the operating temperature of distribution transformers to rise, and shortening the service life. In the actual power system, a bus is often connected to multiple three-phase unbalanced users. The three-phase unbalanced voltage and current among these users affect each other. How to accurately locate the source of the three-phase unbalanced according to...

AI Technical Summary

Problems solved by technology

[0005] 1. The existing responsibility allocation methods, such as impedance approximation method and linearization method, etc., all need to accurately measure the fundamental voltage of the busbar and the fundamental current of each feeder, and use the sampled values ​​​​including amplitude and phase angle to calculate. However, the current power quality monitoring system promoted by the State Grid Corporation of China can only provide 3-minute statistical values ​​of the fundamental voltage and current, which makes all existing methods unsuitable

[0006] 2. Most of the existing responsibility allocation methods are based on short-term measured instantaneous data, but the three-phase unbalance is a long-term steady-state quantity, and the source traceability and responsibility allocation of the three-phase unbalance through short-term instantaneous data measurement is not accurate enough. Difficult to be recognized and accepted by many parties

[0007] 3. At present, the monitoring points of the power quality monitoring system are limited, and it is impossible to monitor each special substation user. However, most of the three-phase imbalances are caused by low-voltage unbalanced users. Only rely on the power quality monitoring installed on the busbar of the substation The monitoring data provided by the terminal cannot accurately measure the voltage and current data of each user, so it is impossible to divide the responsibilities of low-voltage users

[0008] 4. The existing calculation methods of responsibility are all based on the Norton equivalent circuit. In theory, the negative sequence current of the Norton equivalent current source on the system side and each three-phase unbalance source needs to be known. However, since this current cannot be measured, the support is usually used. Due to the coupling and interaction between the three-phase unbalance sources, this approximate calculation will lead to large errors in the calculation of the responsibility index, and even cause the problem of inaccurate tracing of the source of the three-phase unbalance

[0009] 5. The existing responsibility allocation method is greatly affected by the fluctuation of the equivalent negative sequence impedance. At present, the fluctuation of the impedance is equivalent to the fluctuation of the current source current, and then the responsibility division is calculated

This method has a large amount of calculation and errors, and cannot fundamentally solve this problem.

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