Self-decision three-phase self-balancing load zero passage switching method

Abstract

The invention provides a self-decision three-phase self-balancing load zero passage switching method which comprises the following steps of data statistics, line impedance calculation, low-voltage tide emulation, load prediction, self-decision control strategy preparation, and three-phase balancing. The self-decision three-phase self-balancing load zero passage switching method is reasonable in design, can effectively reduce the three-phase unbalance degree, can raise the level of safe, stable and economic operation of a whole power grid, can significantly improve the power supply quality of the power grid, can improve a power factor in real time, can effectively manage power system harmonic caused by three-phase unbalance, can well control voltage fluctuation, can prolong the service lifeof power utilization equipment, can improve the power supply quality of the power grid to meet a national standard, can create a good power supply system for industrial and agricultural production and people living, and can exert purposes of energy saving, consumption reduction and great national resource saving.

Description

technical field [0001] The invention relates to a self-decision-making three-item self-balancing load zero-crossing switching method, which belongs to the technical field of power quality optimization equipment. Background technique [0002] Nowadays, the low-voltage power grid structure of the rural low-voltage power grid has undergone great changes after system transformation, and the weak links in the power grid structure have basically been resolved. The line loss rate has dropped below 11%, but there are still some reasons such as three-phase unbalance in some distribution stations, which cause the line loss rate to remain high, causing great difficulties in the management of power supply companies and great economic losses , and now the energy consumption of the distribution network is mainly concentrated on the transmission line and the user demand side. In the distribution network below 10KV, especially in the 400V distribution network, due to the extensive access of...

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Problems solved by technology

[0002] Nowadays, the low-voltage power grid structure of the rural low-voltage power grid has undergone great changes after system transformation, and the weak links in the power grid structure have basically been resolved. The line loss rate has dropped below 11%, but there are still some reasons such as three-phase unbalance in some distribution stations, which cause the line loss rate to remain high, causing great difficulties in the management of power supply companies and great economic losses , and now the energy consumption of the distribution network is mainly concentrated on the transmission line and the user demand side. In the distribution network below 10KV, especially in the 400V distribution network, due to the extensive access of a large number of industrial and agricultural equipment, various electric energy pollution The widespread use of equipment has brought a lot of energy loss to the power grid. The urban and rural distribution network is the main part of the energy loss of the power system. On the other hand, with the development of modern power grids and changes in load composition, power quality problems have It has attracted great attention from both the power supply and the consumer. Information users who are sensitive to power quality have higher and higher requirements for power supply reliability. Many precision electronic and power electronic devices based on computers and microprocessors are widely used in power systems. The sensitivity of power quality is getting higher and higher, especially for the transient power quality of the power supply system, which puts forward higher requirements to meet the needs of users for power quality and provide users with a variety of optional power quality and price solutions. Therefore, it is an inevitable trend of power grid development planning and construction to comprehensively control the power quality of medium and low voltage distribution networks and take measures to save energy and reduce consumption.

[0003] At present, the existing three-phase unbalanced technologies mainly include two types: (1) The three-phase unbalanced technology based on the principle of centralized voltage compensation at the head end is mainly used to control the three-phase unbalance from the point of view of the head-end assessment; However, this technology mainly relies on power electronic devices, and there are problems with equipment noise, heat generation, and impact on communication; (2) The terminal active load switching switch is difficult to install and implement, and it also needs to rely on communication technology , such as carrier communication or wireless communication, if the communication is interrupted, the intelligent terminal at the head end cannot issue the phase modulation command, and the three-phase load switching switch is effective

[0004] For example, when the power supply department in Kaili, Guizhou Province, was transforming the rural low-voltage power grid in the area, it took measures such as increasing the number of distribution transformers in the distribution area, placing the distribution transformers in the load center, shortening the radius of power supply, increasing the diameter of wires, and building A series of technical transformations based on loss reduction as the standard, such as the transformation of low-voltage lines and the new installation of household lines, have also received good results, but the line loss rate of individual stations is still high due to the three-phase imbalance problem

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