考虑残余电荷分布非均匀性VFTO建模方法及其在电缆上耦合响应测量方法研究

VFTO generated in GIS by operating disconnect has an important effect on IED in smart substation and safety operation of UHV substation. Based on traditional transmission line model and considered nonuniformity of trapped charge on no loaded bus, a new transmission model for analyzing very fast transients overvoltage is presented with current and charge density being variables in this model. Applied numerical electromagnetic method and this model the analysis method for VFTO is studied. Considered operation velocity of disconnect, structure of contact and initial phase of source at start operation the total process of VFTO is analyzed. The critical velocity is obtained for controlling VFTO by initial phase selection and optimum phase is calculated for VFTO control. A new EMI analysis and measurement model are built to obtain lumped equivalent EMI source relative to load end and feasible measurement method is presented. Based on this measurement model the the lumped equivalent EMI source for arial transmission line and shieled cable are obtained by experiments and simulations.With the 252kV GIS experiment platform the suppression effectiveness of phase selection to VFTO is experimently studied. Under different shield condition and different earthing style of shield of shielded cable the coupling response on cable is studied experimentally and theoretically. This project will be beneficial to further know the mechanism of VFTO, suppression measures and EMI measurement method.

GIS内隔离开关操作产生的VFTO对高压开关设备智能组件及特高压输电安全稳定运行有着重要的影响。基于传统传输线模型，考虑GIS内空载母线残余电荷分布非均匀性，提出基于电流和电荷密度的VFTO分析模型；结合电磁场数值计算方法，建立内部VFTO分析方法；考虑隔离开关分合闸速度、动静触头结构和分合闸初始相位分析VFTO的暂态全过程，确定选相分合闸VFTO抑制技术最佳分合闸相位；基于场路耦合方法建立外部VFTO分析方法，计算暂态壳地电位升和空间电磁场分布；建立电缆上相对负载的集中等效电磁干扰源的电磁干扰分析与测量数学模型，理论和实验研究外场激励下架空电缆和屏蔽电缆集中等效电磁干扰源分析方法和实验方法；基于252kVGIS实验平台实验研究隔离开关选相分合闸VFTO抑制技术可行性，实验研究隔离开关操作时电缆不同屏蔽方式和屏蔽层不同接地方式智能组件处集中等效电磁干扰源和及其抑制措施。

气体绝缘变电站（GIS）内隔离开关操作过程产生的特快速暂态过电压（VFTO）严重威胁电力系统安全稳定运行。本项目围绕VFTO分析建模、测量和抑制方法等开展了以下主要研究内容：1、考虑空载母线残余电荷的分布性，建立了VFTO精确分析模型；2、提出了基于集总等效源法的VFTO在变电站二次电缆电磁干扰的新测量方法，为二次电缆VFTO形成的电磁干扰测量方法提供了理论基础，实验验证了方法的有效性；3、提出了综合考虑隔离开关分合闸速度和操作初相位的综合影响的VFTO抑制方法；为了开展实验研究工作，研制了用于隔离开关操作VFTO抑制的选相分合闸装置；为了将来进一步精更确建立VFTO分析模型，本项目还开展了电晕放电研究工作，为将来隔离开关动静触头间建立精确燃弧模型奠定了基础；为了更好地测量VFTO信号，本项目还开展了GIS电压测量方法的研究工作，设计了多个GIS电压测量方法和装置。研究结果表明：1考虑空载母线残余电荷的分布性影响的GIS分析模型更准确；2、集总等效源法二次电缆VFTO测量方法是有效和可行的；3、初步实验表明要想应用选相分合闸方法抑制VFTO，还需要有效控制操作机构的操作过程由于机械等原因带来的随机性；4、电晕放电研究和电压测量方法研究获得丰硕成果，为电弧模型建立和电压测量奠定了基础。本项目研究为GIS内隔离开关操作产生的VFTO抑制提供了理论和实验基础，将有力支持变电站安全稳定运行。