Research On Field Test And Calibration Method Of Wide-frequency Measurement Device

The large-scale access of high proportion of renewable energy and high proportion of power electronic equipment is becoming an important feature of the new power system.A large number of harmonic and inter-harmonic components appear in the electricity volume,and the dynamic behavior is obvious,which seriously threatens the safe and stable operation of the system.It is very important to ensure the measurement accuracy of the wide-frequency measuring device.However,the existing wide-frequency testing lacks the problem of detecting the dynamic situation.Therefore,this paper intends to study the behavior of the wide-frequency electrical volume in field dynamic time varying.In this paper,the high precision test method and test platform for wide-frequency measuring devices are developed,and the dynamic characteristics analysis of wide-frequency signals,the high precision wide-frequency measurement algorithm,and the construction of widefrequency field test platform are studied.The main innovations of this paper are as follows:In view of the lack of field signal analysis and frequency number accurate estimation,the field recording data is analyzed comprehensively to obtain the static and dynamic characteristics of wide-frequency signals in the actual power system,and the corresponding wide-frequency power signal model is established.According to the definition of harmonics and inter-harmonics in existing documents and the requirement of wide-frequency measurement accuracy,the relationship between the frequency resolution of wide-frequency measurement algorithm and the dynamic bandwidth is analyzed,the bandwidth of the wide-frequency component is defined,and the dynamic threshold is set to extract the effective wide-frequency component accurately.An algorithm for estimating the number of signal frequencies applicable to the field is proposed,which provides an accurate reference for further effective calculation of the wide-frequency component and can lay a foundation for accurate measurement of the wide-frequency algorithm.Aiming at the problem that the existing wide-frequency measurement algorithms are not accurate enough in dynamic conditions due to the static model,a dynamic widefrequency multi-component fitting mathematical model based on polynomial is established to accurately describe the dynamic time-varying behavior of wide-frequency electrical volume.A short time window dynamic wide-frequency measurement algorithm based on improved Prony is proposed.By simplifying Prony constraint conditions,the calculation amount of the algorithm is reduced,and the measurement accuracy is guaranteed by frequency iterative solution.Furthermore,the simulation results show that the proposed method can accurately measure harmonics and inter-harmonics under dynamic conditions,and can provide an effective reference for measuring devices.Finally,in order to provide a test platform for the field test of the wide-frequency measuring device,the influence mechanism of timing error,sampling error and signal source on the phasor accuracy is analyzed and verified,and the hardware selection is carried out.Based on this,the calibrator of the wide-frequency measuring device is developed.Furthermore,the test and error analysis of the wide-frequency measuring device are carried out,and the device is tested by the established test platform,which verifies the effectiveness and practicability of the scheme.The results show that the output signal and phasor accuracy of the test platform meet the requirements and can run stably in real time,which provides an effective reference for the subsequent field test technology of mature wide-frequency measuring devices.