Establishing of a 1000 V Multi-Decade Inductive Voltage Divider Standard at NIM

A multi-decade 1000-V inductive voltage divider (IVD) was established at the National Institute of Metrology in China. This multi-decade IVD will function as the 1000-V voltage ratio standard at the power frequency in a traceability system. It can provide a wide output ratio ranging from $1\times 10^{-8}$ to 1 with the accuracy better than $0.05~\mu \text{V}$ /V (in-phase and quadrature). Two different winding connection methods are used to achieve their respective effects. A special structure with four independent shieldings is used at first two windings in order to reduce the IVD’s burden. An error compensation method, which is based on the transformer injection, is introduced to improve the output ratio accuracy. An improved bootstrap calibration method with fully equal potential guards on all parts of the circuits at nonzero potential is presented, and a multi-ratio reference transformer with symmetric leakage design is used to calibrate the multi-decade IVD for combinational usage. The expanded uncertainty of the self-calibration is less than $0.02~\mu \text{V}$ /V.