The real-time transient stability detection and emergency control technology based on wide area response has become a hot research area in power system stability studies.Several different technologies have been propos...The real-time transient stability detection and emergency control technology based on wide area response has become a hot research area in power system stability studies.Several different technologies have been proposed,but lots of problems remain to be solved before they can be applied in practice.A wide area measurement system(WAMS)based test platform is developed for transient stability detection and control.The design as well as main function modules of the platform are introduced.In addition,three generator power angle prediction methods and six response based transient instability detection technologies are given.Results of engineering application demonstrate that the developed test platform can provide a real-time operation environment,which can effectively compare and analyze the validity and practicability of these transient stability detection technologies.Based on the measured perturbed trajectories from actual power systems or the Real-Time Digital Simulators(RTDS),the platform can realize the assessment and visual result presentation of various responses from different transient instability detection technologies.The test platform can be applied to different power systems and it is convenient to embed new transient instability detection modules.Meanwhile some deficiencies and shortcomings in engineering application are pointed out and corresponding suggestions are given.In conclusion,the hardware and software structure,function modulus and engineering applications are presented.The application in actual power systems shows that it has a good application perspective.展开更多
Flow instability in the centrifugal compressor should be detected and avoided for stable and safe operation.Due to the popularity of electric centrifugal compressors,instability detection could be achieved by measurin...Flow instability in the centrifugal compressor should be detected and avoided for stable and safe operation.Due to the popularity of electric centrifugal compressors,instability detection could be achieved by measuring motor signals instead of traditional aerodynamic signals.In this paper,the feasibility of instability detection by motor signals(i.e.rotating speed and phase current)was studied experimentally.The physical structure and control method of the electric centrifugal compressor were discussed to reveal the potential of instability detection by motor signals.Dynamic pressure signals and motor signals measured during unsteady experiments were analyzed in the time domain and frequency domain.Characteristics of these signals were then compared under different operating conditions to indicate the feasibility of instability detection by motor signals.Finally,the ability of Short-Time Fourier Transform(STFT)of rotating speed signals in real-time instability detection was discussed.Results showed that the rotating speed signal is a good alternate for instability detection in spite of signal distortion,while the phase current signal can only detect surge due to the low resolution of the controller.Based on the variations of the amplitude and frequency of rotating speed signals,the real-time instability can be captured accurately by STFT with a window size of 0.5 s.Besides,the interference caused by the controller can be removed by STFT.展开更多
基金Supported by National Natural Science Foundation of China(51577049)Open Foundation of State Key Lab.of Alternate Electrical Power System with Renewable Energy Sources(Grant No.LAPS14005).
文摘The real-time transient stability detection and emergency control technology based on wide area response has become a hot research area in power system stability studies.Several different technologies have been proposed,but lots of problems remain to be solved before they can be applied in practice.A wide area measurement system(WAMS)based test platform is developed for transient stability detection and control.The design as well as main function modules of the platform are introduced.In addition,three generator power angle prediction methods and six response based transient instability detection technologies are given.Results of engineering application demonstrate that the developed test platform can provide a real-time operation environment,which can effectively compare and analyze the validity and practicability of these transient stability detection technologies.Based on the measured perturbed trajectories from actual power systems or the Real-Time Digital Simulators(RTDS),the platform can realize the assessment and visual result presentation of various responses from different transient instability detection technologies.The test platform can be applied to different power systems and it is convenient to embed new transient instability detection modules.Meanwhile some deficiencies and shortcomings in engineering application are pointed out and corresponding suggestions are given.In conclusion,the hardware and software structure,function modulus and engineering applications are presented.The application in actual power systems shows that it has a good application perspective.
基金supported by the National Key Research and Development Program of China(No.2018YFB1501004)。
文摘Flow instability in the centrifugal compressor should be detected and avoided for stable and safe operation.Due to the popularity of electric centrifugal compressors,instability detection could be achieved by measuring motor signals instead of traditional aerodynamic signals.In this paper,the feasibility of instability detection by motor signals(i.e.rotating speed and phase current)was studied experimentally.The physical structure and control method of the electric centrifugal compressor were discussed to reveal the potential of instability detection by motor signals.Dynamic pressure signals and motor signals measured during unsteady experiments were analyzed in the time domain and frequency domain.Characteristics of these signals were then compared under different operating conditions to indicate the feasibility of instability detection by motor signals.Finally,the ability of Short-Time Fourier Transform(STFT)of rotating speed signals in real-time instability detection was discussed.Results showed that the rotating speed signal is a good alternate for instability detection in spite of signal distortion,while the phase current signal can only detect surge due to the low resolution of the controller.Based on the variations of the amplitude and frequency of rotating speed signals,the real-time instability can be captured accurately by STFT with a window size of 0.5 s.Besides,the interference caused by the controller can be removed by STFT.
