Purpose Design and implement a system within the detector electronic box of the FXT payload on the EP satellite to read out and acquire data from the pnCCD module of the focal plane detector.Methods The pnCCD module i...Purpose Design and implement a system within the detector electronic box of the FXT payload on the EP satellite to read out and acquire data from the pnCCD module of the focal plane detector.Methods The pnCCD module is complex to control,has a high data throughput,and poses challenges during readout.This paper presents the design and implementation of a data acquisition system specifically for pnCCD and its readout ASIC,CAMEX.The DAQ includes a dedicated front-end module for signal conversion,a control module for powering the pnCCD on and off and managing its sequence,and a signal preprocessing module that performs real-time corrections for offset and common mode on signals acquired by the ADC.Additionally,the offset module allows for in-orbit calculation and updating of the offset.Results The DAQ operates stably in orbit and functions normally,accurately recording the amplitude,position,and arrival time of signals.This capability enables the production of images and energy spectra,which provide robust support for scientific data analysis on the ground.Conclusion The DAQ has achieved readout and data acquisition for the pnCCD module of the focal plane detector,meeting the requirements of the EP satellite’s FXT payload and operating well in orbit.展开更多
We propose a new scheme for transformer differential protection. This scheme uses different characteristics of the differential currents waveforms (DCWs) under internal fault and magnetizing inrush current conditions....We propose a new scheme for transformer differential protection. This scheme uses different characteristics of the differential currents waveforms (DCWs) under internal fault and magnetizing inrush current conditions. The scheme is based on choosing an appropriate feature of the waveform and monitoring it during the post-disturbance instants. For this purpose, the signal feature is quantified by a discrimination function (DF). Discrimination between internal faults and magnetizing inrush currents is carried out by tracking the signs of three decision-making functions (DMFs) computed from the DFs for three phases. We also present a new algorithm related to the general scheme. The algorithm is based on monitoring the second derivative sign of DCW. The results show that all types of internal faults, even those accompanied by the magnetizing inrush, can be correctly identified from the inrush conditions about half a cycle after the occurrence of a disturbance. Another advantage of the proposed method is that the fault detection algorithm does not depend on the selection of thresholds. Furthermore, the proposed algorithm does not require burdensome computations.展开更多
Background The Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor(GECAM)consists of 2 microsatellites,each of which contains 25 GRD(LaBr3)detectors and 8 CPD(plastic scintillator)detectors.Meth...Background The Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor(GECAM)consists of 2 microsatellites,each of which contains 25 GRD(LaBr3)detectors and 8 CPD(plastic scintillator)detectors.Method silicon photomultiplier(SiPM)array is used to read each detector.The output signal of these detectors with SiPM array is very special and challenging to readout.In this study,a novel data acquisition(DAQ)algorithm for these detectors is designed and implemented,and the content of the output event packet is defined.Result and Conclusion The performances,including the event acquisition efficiency of this DAQ algorithm,are extensively verified through experimental tests.From the on-ground and in-flight tests,this algorithm has excellent performance despite the very limited resources and short development time of GECAM mission.展开更多
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 1531010301).
文摘Purpose Design and implement a system within the detector electronic box of the FXT payload on the EP satellite to read out and acquire data from the pnCCD module of the focal plane detector.Methods The pnCCD module is complex to control,has a high data throughput,and poses challenges during readout.This paper presents the design and implementation of a data acquisition system specifically for pnCCD and its readout ASIC,CAMEX.The DAQ includes a dedicated front-end module for signal conversion,a control module for powering the pnCCD on and off and managing its sequence,and a signal preprocessing module that performs real-time corrections for offset and common mode on signals acquired by the ADC.Additionally,the offset module allows for in-orbit calculation and updating of the offset.Results The DAQ operates stably in orbit and functions normally,accurately recording the amplitude,position,and arrival time of signals.This capability enables the production of images and energy spectra,which provide robust support for scientific data analysis on the ground.Conclusion The DAQ has achieved readout and data acquisition for the pnCCD module of the focal plane detector,meeting the requirements of the EP satellite’s FXT payload and operating well in orbit.
文摘We propose a new scheme for transformer differential protection. This scheme uses different characteristics of the differential currents waveforms (DCWs) under internal fault and magnetizing inrush current conditions. The scheme is based on choosing an appropriate feature of the waveform and monitoring it during the post-disturbance instants. For this purpose, the signal feature is quantified by a discrimination function (DF). Discrimination between internal faults and magnetizing inrush currents is carried out by tracking the signs of three decision-making functions (DMFs) computed from the DFs for three phases. We also present a new algorithm related to the general scheme. The algorithm is based on monitoring the second derivative sign of DCW. The results show that all types of internal faults, even those accompanied by the magnetizing inrush, can be correctly identified from the inrush conditions about half a cycle after the occurrence of a disturbance. Another advantage of the proposed method is that the fault detection algorithm does not depend on the selection of thresholds. Furthermore, the proposed algorithm does not require burdensome computations.
基金The authors would like to thank all colleagues for helpful suggestions and comments.This study was supported by the National Natural Science Foundation of China(Grant No.11803039 and 12173038)the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 15360100 and XDA 15360102).
文摘Background The Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor(GECAM)consists of 2 microsatellites,each of which contains 25 GRD(LaBr3)detectors and 8 CPD(plastic scintillator)detectors.Method silicon photomultiplier(SiPM)array is used to read each detector.The output signal of these detectors with SiPM array is very special and challenging to readout.In this study,a novel data acquisition(DAQ)algorithm for these detectors is designed and implemented,and the content of the output event packet is defined.Result and Conclusion The performances,including the event acquisition efficiency of this DAQ algorithm,are extensively verified through experimental tests.From the on-ground and in-flight tests,this algorithm has excellent performance despite the very limited resources and short development time of GECAM mission.
