A three-phase load automatic balance adjustment system in distribution network platform area

Abstract

The invention discloses a three-phase load automatic balancing adjustment system for a transformer district of a power distribution network. The system comprises a main station control unit, a commutation unit and a communication unit. When a fact that the three-phase unbalance degree of a transformer district load exceeds a preset threshold is detected, the main station control unit obtains an optimal load distribution solution through analytical calculation, and transmits an instruction for making the commutation unit perform three-phase load commutation, thereby making the three-phase load of a transformer district commutation transformer satisfy a balancing requirement. According to the system, a switch device time division multiplexing mode is utilized. Compared with a single-phase switch module assembly, the three-phase load automatic balancing adjustment system has advantages of remarkably reducing an average number of switch devices equipped for each phase, accurately setting switch device on-and-off time through voltage locked-phase information of the main station control unit, realizing no jump of load voltage and no current stoppage through independent control of a bidirectional switch device, ensuring high power consumption stability of a client, and furthermore satisfying a requirement for balanced three-phase load of the transformer.

Description

technical field [0001] The invention relates to the field of three-phase load balance control in a distribution transformer low-voltage station area, in particular to an automatic three-phase load balance adjustment system in a distribution network station area. Background technique [0002] The unbalanced three-phase load of the transformer will cause problems such as transformer overload, increase transformer loss, and affect the power quality of users. There are three ways to add a commutation switch on the side of a single-phase outgoing line. Manual adjustment is time-consuming and labor-intensive, and requires power outage processing. However, installing an adjusting device on the outlet side of the transformer has a limited scope of application and cannot cope with the occasions where users are scattered, the number of transformer outlet cables is small, and there are many cable branch boxes on the user side. The current commutation switch device adopts the combinat...

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Problems solved by technology

[0002] The unbalanced three-phase load of the transformer will cause problems such as transformer overload, increase transformer loss, and affect the power quality of users. There are three ways to add a commutation switch on the side of a single-phase outgoing line

Manual adjustment is time-consuming and labor-intensive, and requires power outage processing

However, installing an adjustment device on the outlet side of the transformer has a limited scope of application and cannot cope with the scattered distribution of users, the number of transformer outlet cables is small, and there are many cable branch boxes on the user side.

The current commutation switch device adopts the combination of three sets of bidirectional thyristors and electromagnetic switches for each phase load. The commutation method adopts the method of turning off one phase, fixing a delay, and opening the other phase. There are voltage jumps and currents in the load. cut off

Moreover, the single-phase load adjustment does not take into account that the capacity of the branch box has been evenly distributed during the initial new installation design process. There may be an extreme situation where all the loads of a certain branch box are on a certain phase power supply, and there is a single-phase overload of the branch box. Hidden dangers

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