A three-phase load unbalance adjustment device

Abstract

The invention discloses a three-phase load unbalance adjustment apparatus. The three-phase load unbalance adjustment apparatus comprises three current transformers, a voltage sensor, an intelligent controller, a load switching module and two (or more than two) load access modules, wherein the intelligent controller comprises a central processing unit, a current detection unit, a voltage detection unit, a synchronous detection unit, a storage unit and a communication unit 0. When the load unbalance degree exceeds a standard requirement, the apparatus can automatically switch the phase lines accessed to the power system by a single phase load to enable three-phase load to be balanced; the load is not power off in the switching process, so that the normal use of the common domestic appliances is not affected; in a low voltage power grid, the three-phase unbalance of the power grid is adjusted by the three-phase load unbalance adjustment apparatus; and the adjustment is low-cost, direct and effective adjustment way, and has quite high feasibility and relatively high economic benefits.

Description

technical field [0001] The invention relates to the technical field of low-voltage power grid power electronics, in particular to a three-phase load unbalance adjustment device. Background technique [0002] In the transformation of the rural power grid, measures such as placing distribution transformers at the load center, shortening the power supply radius, and selecting wires with larger cross-sectional areas have been taken, which has greatly improved the situation of the rural low-voltage power grid and built a good power grid "hardware". [0003] After the transformation of the rural power grid and the implementation of "same grid with the same price", a large number of high-power household appliances have entered the homes of ordinary people, resulting in a surge in single-phase loads, and the problem of unbalanced three-phase loads has become more and more serious, resulting in poor operating conditions of the power grid. Unbalanced three-phase load, one or two phase...

AI Technical Summary

Problems solved by technology

[0003] After the transformation of the rural power grid and the implementation of "same grid with the same price", a large number of high-power household appliances have entered the homes of ordinary people, resulting in a surge in single-phase loads, and the problem of unbalanced three-phase loads has become more and more serious, resulting in poor operating conditions of the power grid

Unbalanced three-phase load, one or two phases are abnormally heavy, will increase the voltage drop of the line, reduce the voltage quality of the user, and affect the user's production and domestic electricity consumption; when the three-phase current imbalance is large, the resulting The zero-sequence current is very large, and sometimes even blows the zero line of the system, so that the neutral point of the load moves to the phase with a large load, the phase voltage of the phase with a large load decreases, and the voltage of the phase with a small load increases. If the voltage greatly exceeds the rated voltage of low-voltage electrical appliances, it will cause a large number of household appliances to burn out; the unbalanced three-phase load will increase the loss of transformers and low-voltage power grids, which will cause the transformers and lines to burn out due to severe heat. Power supply costs, on the other hand, power outage maintenance will cause long-term power outages, which reduces the reliability of power supply and affects the economic benefits of power supply companies

[0004] At present, the domestic solution to the problem of unbalanced three-phase loads in low-voltage distribution networks usually adopts the method of manually switching single-phase load power supply phases, but this method has certain limitations.

On the one hand, due to frequent load changes, frequent switching adjustments are required, which increases labor costs; on the other hand, manual switching requires the configuration of load monitoring equipment to ensure the correctness of load commutation, and the load needs to be powered off before commutation. operation, the power outage time of the load often exceeds 30 minutes, which seriously affects the normal power consumption of users

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