零序电压是决定中性点非有效接地配电网故障消弧、保护和过电压的一个重要参数，配电网柔性接地技术通过有源控制零序电压，灵活控制接地故障残流、降低三相不平衡过电压、有利于实现残流增量接地保护及抑制铁磁谐振过电压，是配电网接地与调谐的一个重要发展方向。项目在课题组提出的配电网柔性接地概念及前期研究的基础上，重点研究基于电力电子系统的零序电压有源控制理论与方法。一方面研究有源逆变回路与配电网的相互作用机理，理论上探讨配电网零序阻抗对注入电流回路效率和谐波的影响，提出配电网零序电压有源控制装置拓扑结构优化方法；另一方面研究基于输出电流与零序电压解耦的柔性接地装置电流控制方法，实现输出电流的独立控制，并提升装置控制系统的整体性能。研究成果有助于实现精确、高效、可靠的配电网零序电压控制系统，促进配电网接地消弧与保护技术的发展。

Zero-sequence voltage is a key coefficient for fault arc-extinguishing, protection and overvoltage in the neutral ineffectively grounded distribution power grid. Distribution network flexible grounding technology can realize grounding fault residual current constraint, three-phase unbalance overvoltage reduction, residual current incremental grounding protection, and ferroresonance overvoltage suppression through controlling the zero-sequence voltage. Based on the proposed flexible grounding concept and the preliminary researched accomplishment, this project focuses on zero-sequence voltage active control theory and method. For one thing, the interaction between the single-phase inverter and the distribution network is to be researched and the zero-sequence active control device topology optimal method is to be proposed. For another, the current control method based on the output voltage and current decoupling is to be researched, which assures the independent control of output current and promoting the overall performance of the control system. The research achievement is anticipated to realize a precise, effective and reliable zero-sequence voltage control system, and enhance the theory of fault suppression and protection in distribution network.