Evaluation And Improvement Of Immunity Test Method For Secondary Equipment In Substation And Converter Station

In the context of the increasingly complex electromagnetic environment and the increased electromagnetic sensitivity of the secondary equipment in the power system,in order to ensure the reliable operation of the secondary equipment and improve the anti-electromagnetic interference capability,this thesis focuses on the statistical characteristics of transient electromagnetic disturbances of secondary equipment in substations and converter stations,evaluates and improves the immunity test methods of secondary equipment.Due to the transient electromagnetic disturbance characteristic parameters’ small sample,large dispersion,and unknown distribution form,this paper proposes a bias-corrected bootstrap confidence interval estimation method based on the principle of random weighting method.The application of this statistical method obtains the statistical mean and confidence interval of the measured transient electromagnetic disturbance characteristic parameters with the help of computer tools.The uncertainty evaluation method for the characteristic parameters of transient electromagnetic disturbance is proposed,and impoves the quantitative research method of characteristic parameters of transient electromagnetic disturbance.The transient disturbance voltage measurement of the secondary equipment port was carried out at the substation site.First,the time domain and frequency domain characteristic parameters of the disturbance voltage were statistically analyzed.Then the conformity of analysis results with the parameters of immunity test such as ringing wave,surge and damped oscillation wave were evaluated.Finally the recommendation for increasing the immunity test voltage of ringing wave and surge to 6kV are put forward.Based on the principle of waveform correlation,the similarity between a large number of measured transient disturbance waveforms and the immunity test waveforms is compared.On this basis,it is proposed to increase the test frequency of 20kHz ringing wave and 7.7MHz damped oscillatory wave and improve the attenuation parameters of 100kHz damped oscillatory wave.The increase in test frequency and improvement of waveform parameters cover more measured disturbance waveforms,making the immunity test more realistic.