Determining the voltage ratio change is one of the core issues in the traceability of the DC voltage divider. Basing on the previous research results, this study proposes an improved DC voltage summation method to evaluate the voltage division ratio error of 1000 kV DC resistance divider. The principle of the method is to calibrate the voltage divider with rated voltage 2U by using two auxiliary voltage dividers which are with rated voltage U, wherein the high-voltage (HV) arm and the low-voltage arm of the auxiliary voltage divider can be separated. Research results show that compared with the conventional method, the method can reduce one measurement variable when determining the divider's ratio change, thus simplifying the calibration process. The voltage ratio of 100 kV measured by the method of this study was well-verified by the calibration results from the National Institute of Metrology (NIM, China) and Physikalisch-Technische Bundesanstalt (PTB, Germany). Using the proposed method, the ratio change of DC voltage divider at an applied voltage of 1000 kV was effectively obtained and the uncertainty of 2.5 μV/V was achieved. Research results can provide technical guarantee for the accurate measurement of HVDC magnitude.

中文翻译：

---

基于改进的直流电压求和法的1000 kV直流高压分压器比率变化测量研究

确定电压比变化是直流分压器可追溯性的核心问题之一。根据以前的研究结果，本研究提出了一种改进的直流电压求和方法，以评估1000 kV直流电阻分压器的分压比误差。该方法的原理是通过使用两个额定电压为U的辅助分压器来校准额定电压为2U的分压器，其中辅助分压器的高压（HV）臂和低压臂可以是分开。研究结果表明，与传统方法相比，该方法在确定分频比变化时可以减少一个测量变量，从而简化了校正过程。通过本研究方法测得的100 kV电压比已通过美国国家计量学会（NIM）和德国物理技术联合会（PTB）的校准结果得到了很好的验证。使用所提出的方法，有效地获得了在1000 kV施加电压下直流分压器的比率变化，并且实现了2.5μV/ V的不确定度。研究结果可以为高压直流输电的准确测量提供技术保证。