摘要
Abstract
[Objective]The integration of high-penetration photovoltaics and high-power electric vehicles has altered the operating characteristics of power systems,resulting in frequent wide-range voltage fluctuations.This imposes stricter requirements on the voltage regulation speed,range,and capacity of distribution transformers.Traditional distribution transformers,limited by the high-voltage side,exhibit small tap steps and slow voltage regulation speeds,making wide-range voltage regulation impossible.To address this issue,this study proposes a novel hybrid wide-range voltage regulation method on low-voltage side based on active inversion,which connects the tap changer to the low-voltage side of the distribution transformer to achieve wide-range voltage regulation.[Methods]To address the challenges of high switching currents and large conduction losses on the low-voltage side,an inverter power source was incorporated into the power electronic commutation branch.A voltage-current dual-loop competition strategy was employed to regulate the control signals of the inverter circuit,offsetting the forward voltage of electronic components and enabling zero voltage across the mechanical branch.Meanwhile,the inverter circuit was activated to generate load current,forcing current commutation from the mechanical branch to the power electronic commutation branch,thus achieving zero current in the mechanical branch.This ensured true zero-voltage and zero-current operation of the mechanical switch,solving the problem of incomplete arc extinction in traditional hybrid switches.[Results]The simulation results showed that the inverter power supply provided zero-voltage and zero-current conditions for the mechanical switch,enabling arc-free operation.Compared to traditional hybrid switches,the proposed novel hybrid wide-range voltage regulation method on the low-voltage side reduced the voltage regulation time by at least four times.Moreover,it generated significantly lower arc energy during switching.After 300 000 switching operations,the mechanical contacts had a remaining service life index of 97.2％,demonstrating relatively long service life,while traditional hybrid switches exhibited a service life index of only 37.9％.[Conclusion]The proposed novel hybrid wide-range voltage regulation method on the low-voltage side achieves rapid,wide-range,and low-loss voltage regulation.关键词
配电变压器/低压侧宽幅调压/逆变电路/零电压动作/零电流动作Key words
distribution transformer/wide-range voltage regulation on low-voltage side/inverter circuit/zero-voltage operation/zero-current operation分类
动力与电气工程
