1000kV串联式标准电压互感器的研制

Development of 1000 kV Series Standard Potential Transformer

为了满足在1000kV级特高压电网建设中开展工频电压量值溯源及量值传递工作的需要,对一种基于工频电压加法原理的1000kV串联式标准电压互感器(TV)结构进行了设计,并建立了相关的数学模型。考虑到由于高压隔离互感器(HVIT)绝缘距离的存在而引入的大漏感量严重影响了其准确度,特采用了在HVIT一次侧串联电容的方式对漏感抗进行补偿的方法,大大提高HVIT的准确度。针对上、下级结构电容相差太大而导致的分压不均问题,通过在上级并联高压电容器的方法加以解决,并通过有限元分析对电场进行了仿真计算,验证了设计的可行性。与传统的电磁式标准电压互感器相比,该设计在满足相关规程规定的工频耐压与准确度要求的前提下大大降低了单台互感器的体积、质量及绝缘要求,为开展频繁的现场检定工作创造了条件。

To meet the requirements of the traceability and transfer of voltage value in the construction of 1000 kV ultra high voltage （UHV） power grid, a design of series standard potential transformer is presented based on the theory of power frequency voltage summation method ,and the relevant mathematic model is established. However, the accuracy of the high voltage isolation transformers （HVIT） greatly is influenced by huge leakage inductance, so a method of compensation for the leakage inductance is adopted by connecting the capacitance in series on primary windings of HVIT. Experimental results prove that the method can increase the accuracy of HVIT greatly and thus guarantee the whole accuracy of sspT. Referring to the uneven divided voltage caused by great difference of upperlower structural capacitance, a method of cbnnecting the capacitance in parallel on the upper part of SSPT is put forward, and the feasibility of the method is proved through finite element analysis. Compared with the traditional electromagnetic standard potential transformers, the method can greatly reduce the volume, Weight and insulation requirements of single transformer on the premise of meeting relative requirements of the power frequency voltage withstand as well as the accuracy.