On-line three-phase load unbalance processing method suitable for low-voltage distribution network

Abstract

The invention provides an on-line three-phase load unbalance processing method suitable for a low-voltage distribution network. The on-line three-phase load unbalance processing method comprises the following steps of: monitoring three-phase load by three-phase load monitoring units on the low voltage side of a distribution transformer, and transmitting monitoring data to three-phase load unbalance monitoring units of the distribution transformer; judging whether the three-phase load unbalance exceeds a standard value or not by the three-phase load unbalance monitoring units of the distribution transformer; if the three-phase load unbalance exceeds the standard value, transmitting signals to an on-line load phase modulation control unit by a communication unit; judging whether the three-phase load unbalance of the distribution transformer is caused by the three-phase load unbalance of a main low-voltage circuit or not by the on-line load phase modulation control unit; and if so, setting an on-line load phase modulation strategy according to the monitoring data of the load monitoring units of branches of three phases of the main low-voltage circuit, sending a control command to an on-line load phase modulation switch combination unit by an on-line load phase modulation judging and controlling unit, and switching the load phases of the branches of users so as to realize the on-line three-phase load unbalance processing.

Description

technical field [0001] The invention relates to the field of power systems, in particular to an on-line method for controlling three-phase load unbalance in a low-voltage distribution network. Background technique [0002] In some areas, the low-voltage lines in the distribution station area are long, and there are a large number of single-phase loads. The unbalanced three-phase load in the distribution station area is common. The loss of transformers and low-voltage lines increases, the actual output of distribution transformers decreases, and it is easy to cause low voltage for users on heavy-duty phases, which cannot meet the normal production and living electricity needs of rural residents. Although the three-phase unbalanced management measures can reduce the severity of the unbalanced three-phase load in the distribution area to a certain extent, due to the randomness and uncertainty of the power load, the unbalanced three-phase load occurs It has strong real-time per...

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Problems solved by technology

[0002] In some areas, the low-voltage lines in the distribution station area are long, and there are a large number of single-phase loads. The unbalanced three-phase load in the distribution station area is common. The loss of transformers and low-voltage lines increases, the actual output of distribution transformers decreases, and it is easy to cause low voltage for users on heavy-duty phases, which cannot meet the normal production and living electricity needs of rural residents

Although the three-phase unbalanced management measures can reduce the severity of the unbalanced three-phase load in the distribution area to a certain extent, due to the randomness and uncertainty of the power load, the unbalanced three-phase load occurs It has strong real-time performance, and it cannot be adjusted frequently online according to the actual load imbalance by manual work, and there are safety hazards to a certain extent. Offline adjustment of the load distribution on each phase of the low-voltage line will inevitably affect the power supply to users reliability

At present, some rural areas adopt the method of phase-to-phase reactive power compensation on the low-voltage side of the distribution transformer to adjust the unbalanced three-phase load, but this method can only adjust the problem of the distribution transformer itself to a certain extent, but cannot solve the three-phase load of the low-voltage line unbalanced situation

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