特高压混合无功补偿对单相接地故障开断与潜供电弧特性的影响机理

The hybrid reactive compensation using stepped controllable shunt reactor and series compensation may find application in Ultra High-Voltage (UHV) transmission line, which can be propitious to both the rapid growth of transmission power and frequent adjustment of reactive power. Low frequency oscillation may occur in single phase grounding fault of UHV transmission line with hybrid reactive compensation. As a result, the interruption of circuit breakers and self- extinguishing of secondary arc become difficult. The influence mechanism of hybrid reactive compensation on both single phase grounding fault interruption and secondary arc characteristics needs to be explored in depth. With establishing electromagnetic transient accurate model of hybrid reactive compensation, the quantitative relationship of amplitude characteristic, frequency characteristic, and attenuation characteristic with technical parameters of controllable shunt reactor and series compensation will be deduced in the proposed project. Combined with dynamic modeling theory of circuit breaker interrupting process and interruption criterion, with a view to the generation mechanism and new characteristics of low frequency oscillation of single phase grounding fault current, the interrupting transient characteristics of circuit breaker under low frequency oscillation fault current will be revealed to established quantitative index system between state characteristic parameters of interrupting single phase grounding fault and severity. From a multiple-scale point of view in terms of electromagnetics, hydrodynamics and chain piecewise law, the physical intrinsic nature of low frequency oscillation secondary arc plasma from macroscopic and microcosmic under the coupling of surrounding spatial electromagnetic, fluid fields and environment will be obtained based on the physical experiment and image three-dimensional reconfiguration technology. And the arcing and self-extinguishing physical essence of secondary arc in UHV power grid with the hybrid reactive compensation will be uncovered. The proposed research can develop fundamental theory and analytical approach of hybrid reactive compensation technology, which presents academic significance and application prospects.

串补和分级可控高抗相结合的混合无功补偿能兼顾输送功率增长和无功功率频繁调节，有望在特高压输电线路应用。单相接地故障在特高压混合无功补偿作用下可能发生低频振荡，导致断路器开断和潜供电弧自熄困难，其影响机理有待于深入研究。本项目将建立特高压混合无功补偿电磁暂态准确模型，研究短路电流低频振荡幅频特性、衰减特性与串补和分级可控高抗技术参数的定量关系，结合断路器开断过程动态建模理论与开断判据，揭示计及短路电流低频振荡产生机理的断路器瞬态开断特性，形成单相接地故障开断过程的状态特征参数与苛刻度量化指标体系；基于物理模拟实验和图像三维重构技术以及电磁学、流体力学和链式分段分析方法，获得空间电磁场、流场及环境多场耦合作用下低频振荡潜供电弧等离子体的时空微观与宏观物理特性，阐明混合无功补偿下潜供电弧燃弧与自熄的本质特征。本研究可发展特高压混合无功补偿技术的基础理论与分析方法，具有重要的学术意义和应用价值。

串补和分级可控高抗相结合的混合无功补偿能兼顾输送功率增长和无功功率频繁调节，有望在特高压输电线路应用。在特高压混合无功补偿作用下输电线路可能发生低频振荡，导致断路器开断和潜供电弧自熄困难，其影响机理有待于深入研究。本项目建立了特高压混合无功补偿电磁暂态准确模型，研究了故障电流低频振荡幅频特性、衰减特性与串补和分级可控高抗技术参数的关系，揭示了计及故障电流低频振荡产生机理的断路器瞬态开断特性，形成断路器开断过程的状态特征参数与苛刻度量化指标体系；基于物理模拟实验和图像边缘检测技术以及潜供电弧数值模拟的理论模型，获得潜供电弧电气特征与弧柱形态、运动特征及起始前的等离子体状态，初步揭示了混合无功补偿下潜供电弧燃弧与自熄的特征。本研究可为发展特高压混合无功补偿技术奠定理论和技术基础，具有重要的学术意义和应用价值。