The optical system of the electron cyclotron emission imaging diagnostics on the HL-2A tokamak has been optimized in both the narrow zoom pattern and the wide zoom pattern. The two main features of the improved optica...The optical system of the electron cyclotron emission imaging diagnostics on the HL-2A tokamak has been optimized in both the narrow zoom pattern and the wide zoom pattern. The two main features of the improved optical system are（1） larger coverage of the measurement region in the plasma and（2） a flatter imaging surface. The new optics has good focal characteristics over the whole plasma cross section. The curvature of the field of the image surface（ΔR between the core channel and the edge channel） is within 5.3 cm in the narrow zoom pattern and 6.7 cm in the wide zoom pattern after optimization, whereas the values with the present optics were 23 cm in the narrow zoom pattern and 15 cm in the wide zoom pattern. The optics will be fabricated, tested and installed on the HL-2A tokamak before the next experimental campaign.展开更多
Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability performance.Hence,multi-channel systems are used in such systems within industrial faciliti...Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability performance.Hence,multi-channel systems are used in such systems within industrial facilities to isolate machinery when there are process abnormalities.Inevitably,multi-channel systems introduce Common Cause Failure(CCF)since the subsystems can rarely be independent.This paper integrates CCF into the Markov reliability model to enhance the model flexibility to investigate synchronous generator intra-bay SCN architecture reliability performance considering the quality of repairs and CCF.The Markov process enables integration of the impact of CCF factors on system performance.The case study results indicate that CCF,coupled with imperfect repairs,significantly reduce system reliability performance.High sensitivity is observed at low levels of CCF,whereas the highest level of impact occurs when the system diagnostic coverage is 99%based on ISO 13849-1,and reduces as the diagnostic coverage level reduces.Therefore,it is concluded that the severity of CCF depends more on system diagnostic coverage level than the repair efficiency,although both factors impact the system overall performance.Hence,CCF should be con-sidered in determining the reliability performance of mission-critical communication networks in power distribution centres.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB104000)
文摘The optical system of the electron cyclotron emission imaging diagnostics on the HL-2A tokamak has been optimized in both the narrow zoom pattern and the wide zoom pattern. The two main features of the improved optical system are（1） larger coverage of the measurement region in the plasma and（2） a flatter imaging surface. The new optics has good focal characteristics over the whole plasma cross section. The curvature of the field of the image surface（ΔR between the core channel and the edge channel） is within 5.3 cm in the narrow zoom pattern and 6.7 cm in the wide zoom pattern after optimization, whereas the values with the present optics were 23 cm in the narrow zoom pattern and 15 cm in the wide zoom pattern. The optics will be fabricated, tested and installed on the HL-2A tokamak before the next experimental campaign.
文摘Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability performance.Hence,multi-channel systems are used in such systems within industrial facilities to isolate machinery when there are process abnormalities.Inevitably,multi-channel systems introduce Common Cause Failure(CCF)since the subsystems can rarely be independent.This paper integrates CCF into the Markov reliability model to enhance the model flexibility to investigate synchronous generator intra-bay SCN architecture reliability performance considering the quality of repairs and CCF.The Markov process enables integration of the impact of CCF factors on system performance.The case study results indicate that CCF,coupled with imperfect repairs,significantly reduce system reliability performance.High sensitivity is observed at low levels of CCF,whereas the highest level of impact occurs when the system diagnostic coverage is 99%based on ISO 13849-1,and reduces as the diagnostic coverage level reduces.Therefore,it is concluded that the severity of CCF depends more on system diagnostic coverage level than the repair efficiency,although both factors impact the system overall performance.Hence,CCF should be con-sidered in determining the reliability performance of mission-critical communication networks in power distribution centres.
