An unbalance compensation system and method against voltage distortion

Abstract

The present disclosure provides an unbalance compensation system and method for resisting voltage distortion, which detects the unbalanced current and voltage at the grid-connected point, obtains the required output current command according to it, controls and adjusts the output current, and corrects the unbalanced distribution network The current is rebalanced; according to the output current command and the input voltage value, under the constraints of charge and discharge current limit and capacitor withstand voltage, the current working mode and target voltage control command are calculated to control the balance of voltage and realize the voltage balance. Coordinated control of balanced compensation output, the disclosure can improve the output immunity of the system, improve the accuracy of the compensation current, and reduce the system output harmonic current pollution.

Description

technical field [0001] The present disclosure relates to an unbalance compensation system and method against voltage distortion. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] The explosive growth of load and the rapid development of distributed renewable energy have had a huge impact on the three-phase load balance problem of traditional power supply and distribution systems. In the case of unbalanced three-phase output, distribution transformers are prone to over-running, resulting in supply voltage Serious problems such as distortion, increased loss, line overload, and even transformer damage and power outage. As people's needs for a better life change, users' requirements for power quality are also increasing. Traditional methods such as phase modulation and capacity expansion have been difficult to deal with random and uncertain lo...

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Problems solved by technology

[0003] The explosive growth of load and the rapid development of distributed renewable energy have had a huge impact on the three-phase load balance problem of traditional power supply and distribution systems. In the case of unbalanced three-phase output, distribution transformers are prone to over-running, resulting in supply voltage Serious problems such as distortion, increased loss, line overload, and even transformer damage and power outage

As people's needs for a better life change, users' requirements for power quality are also increasing. Traditional methods such as phase modulation and capacity expansion have been difficult to deal with random and uncertain load imbalance problems in a low-cost, timely and fast manner.

Emerging energy storage devices can alleviate the peak demand of users for electricity consumption, but they cannot control imbalance and harmonics. At the same time, in the process of generating electricity to the grid, due to the impedance and distribution parameters of the end lines of the distribution network, it is difficult to fully realize the three-phase Symmetrical, the imbalance of each phase load on the line is serious, and the random energy storage grid connection process will further affect the voltage of the grid connection point, resulting in fluctuations and voltage distortions, which not only affect the economy and stability of the energy storage device, but also lead to line instability. Balance and excessive loss will also cause destructive impact on distributed power generation systems and user electrical equipment, equipment damage, large-scale power outages and other adverse consequences

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