Metrological Standard Device Of Heavy Direct Current

The confinement index was presented that energy consumption per GDP would be decreased by 20% during the process of eleventh-five year plan. Researches on methods of high accuracy measurement and spot fast measurement, verification and calibration are clearly puts forward by the National Quality Test Center. Now, DC consumption can't be measured in electrolytic aluminum enterprise and electrolytic caustic soda enterprise etc., which will be lead to serious energy waste. Therefore, metrological standard device and quantity-transfer system to monitor heavy direct current are established to unify the national heavy direct current value, then to evaluate electric consumption of those enterprise scientifically, which is in the face.Metrological standard deviceof heavy direct current—high precision current adder is a new high precision instrument which measures the summation of six roads DC directly. Firstly, this article introduces the principles of magnetic modulator and direct current comparator, and direct current comparator is applied to research on the current adder. Secondly, the designs of structure and windings of magnetic modulator are presented. Magnetic modulator relates to sensitivity and algorithm of the current adder, so the design of magnetic modulator is a key one of designs of the current adder. Thirdly, main circuits of the current adder including excitation resource system and feedback system etc.. Finally, error analysis of the current adder are given, and paired experiment and sensitivity test of measuring cores of magnetic modulator of the current adder are made, and then system precision is simulated by MATLAB.The results of experiments and simulations show that the current adder has high sensitivity, and reliable stability and good dynamic response performance, and the precision of the current adder is more than 0.005. Therefore, direct currents can be added by the current adder precisely, and measurement devices of heavy current can be corrected by the current adder as a metrological standard unit, which can realize on-line testing of hundreds KA of large sensors.