Research On The Quantity Traceablity Hierarchy Of Standard Impulse High Voltage Measurement System

The lightning impulse peak parameter and lightning impulse time parameters are listed in the calibration and measurement capabilities?CMCs?of BIPM which belong to the part of high voltage and current measurement within the electromagnetic field.Accurate and reliable high voltage measurement parameters are the key factors to the sustainable operation of high voltage electrical equipment,preventing insulation damage and safety ensurance of the transmission lines.The measurement value of the impulse high voltage equipments shall be traced to the national standard by a continuous calibration chain within the specified measurement uncertainty.However,different from the traditional measurement of steady signals such as DC high voltage and AC high voltage,difficulties arise when it comes to the traceability of impulse high voltage parameters due to high amplitude,wide frequency band and could be easily affected by the surrounding environment and influenced by the stray parameters.In order to further promote the domestic related organizations and institutions for the accreditation of high voltage measurement system and trace to the national standards,ensure the value unification of the impulse high voltage parameters within China and also compatible with the international standards,study on the establishment of the standard high voltage measurement system according to the requirements of the IEC high voltage testing standards will has a great important impact for the traceability system.In this paper,a standard high voltage measuring system was established which involved in the development of the impulse divider,evaluation of the impulse digital oscilloscope and the impulse measurement software.This standard system can perform self calibration independently for the impulse scale factor and the time parameters.The influences of the different type of non-inductance winding of the high voltage arm and the shapes of the supporting frame cross section on the residual inductance were studied intensively.Results showed that a rectangular cross section frame structure with Ayrton Perry winding method can effectively reduces the residual inductance of the divider and keeps the scale factor stable.In order to compensate the leakage current due to the stray capacitance along the high voltage arm to earth,the shielding electrode with double donuts structure was designed by simulation and experiment.Dynamic non-linearity test is required in order to evaluate the transient characteristics of A/D converter in recording standard lightening impulse and chopped impulse.China national standard and also the IEC standard recommend testing with triangular waveform.However,it is difficult to fulfill the requirement with the designated rapid slope using triangular waveform.This paper analyzed the code probability of ideal sin-wave through mathematic model and successfully realized the digital oscilloscope dynamic non-linearity and histogram testing using sin-wave instead of triangular waveform.The result showed that the sin-wave is superior to the triangular waveform in traceability and has tiny distortion in a wide range of frequency range.Evaluation is completely applicable using sin-wave to replace triangular wave in the dynamic non-linearity testing of digital oscilloscope.A creative method was introduced in this paper for the calibration of impulse scale factor which traced the peak voltage to the DC voltage.The normalized step reponse and the double exponential fitting signal were used to determine the dynamic performance of the measurement system by convolution.Measurement uncertainty was greatly reduced with proposed method.Experiment and simulation results showed that the error of a cascaded system for the measurement of lightning impulse equal to the algebraic sum of the error of the individual components approximately.This conclusion showed good agreement to the reference system specified in the IEC60060-2 and can be used in error correction of reference divider for both impulse scale factor and time parameters.On the basis,the deconvolution combining with the linearity experiment were applied to the ultra high voltage and damping divider waveform parameters correction.The dynamic characteristic of the 300kV impulse voltage divider developed in this paper was tested in the high voltage measurement centre in china.Results showed that the partial response time of the impulse divider is4.37ns,the experimental response time is-2.15ns,the settling time is 131ns.Measurement uncertainty evaluation for the peak value is U_rel=0.8%?k=2?,front time T₁ is U_rel=4%?k=2?and U_rel=2%?k=2?for the half peak time of T₂.This implied that the impulse high voltage measurement system developped in this dissertation meet the requirements specified in the IEC60060-2standard for the reference measurement system.