Distributed type power supply zone branch circuit three-phase load current balance monitoring method and device

Abstract

The invention discloses a distributed type power supply zone branch circuit three-phase load current balance monitoring method and device and belongs to the field of power supply and distribution devices. At least one three-phase load current balance main controller is arranged, load current signals of each phase circuit in each branch loop are collected, according to the obtained load current signals of each phase circuit, the three-phase current unbalance rate or the mean value of the three-phase current unbalance rate of each branch loop is computed, and the unbalance situation of three-phase load current of each branch loop is judged. The magnitude of load current in each unit meter box of each branch loop is collected, and the phase of unit meter box load which needs to be adjusted is determined. According to the three-phase load current unbalance situation of a certain branch, a control instruction is issued to an automatic phase-changing switch in a unit meter box corresponding to the branch loop, converting of load phases is carried out, adjusting of three-phase load current balance of each branch loop on the low-voltage side of a distribution transformer is achieved, and the real balance of distribution transformer low-voltage side main loop three-phase load current is guaranteed.

Description

technical field [0001] The invention belongs to the field of power supply or power distribution devices, and in particular relates to a method and a device for balancing the load distribution between phases of three-phase power supply lines or reducing asymmetry. Background technique [0002] The current power system (or power supply system, the same below), especially the low-voltage power grid, generally adopts a three-phase four-wire system for power supply. etc.) are all single-phase loads, and the power consumption and power consumption time of each residential user are different, which leads to the increasingly serious phenomenon of unbalanced three-phase load current in the low-voltage power grid, and seriously affects the operation safety and security of the power supply network. Power quality. [0003] As a whole power supply system, in the three-phase four-wire power supply line, it is very necessary to balance the load distribution among the phase lines, which no...

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Problems solved by technology

[0006] The disadvantages of this technical solution are: firstly, the technical solution must complete the entire information transmission and control process through a third-party communication service provider (GPRS communication network), which will generate additional communication costs and virtually increase power supply costs and operating costs. In addition, because the public network (referred to as the public network) provided by the third-party network operator other than the power supply company is connected to the private local area network (referred to as the internal network) of the power bureau, there is a danger of virus intrusion, which will inevitably affect the power supply. Network security of the company's entire LAN system

[0008] The disadvantage of this technical solution is that the three-phase current collected by the power load distribution host of the power supply company is the main circuit current of the distribution transformer, and the adjustment object is the balance of the three-phase load current in the main circuit of the transformer.

In fact, the balance of the three-phase load current in the main circuit of the transformer is not equal to the balance of the three-phase load current on the power supply branch. Due to the unbalanced three-phase load current on the power supply branch, the "line loss" of the power supply line still cannot be reduced; and in In the actual operation process, it is possible that a certain power supply branch circuit that is already in the state of three-phase load current balance, because the three-phase load current balance of the main circuit is adjusted, the adjusted load is unbalanced, which increases the power supply line. "Line Loss"

[0009] It can be seen that when the three-phase current of the transformer or the main power supply circuit is unbalanced, or when the three-phase load current on a certain power supply branch is unbalanced, how should "detect the unbalance of the three-phase current"? Where exactly should "detect the unbalance of the three-phase current"? "Where should the three-phase load current be adjusted, can the balance of the three-phase load current on the main and branch circuits on the low-voltage side of the distribution transformer be truly realized"? It is a key technical problem that has not been solved (well) in the actual power grid operation and management, which hinders the safe operation of power supply lines and the real and effective implementation of "line loss" work, and affects the quality of power supply

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