The cone-shaped kernel distributions of vibration acceleration signals, whichwere acquired from the cylinder head in eight different states of a valve train, were calculatedand displayed in grey images. Probabilistic ...The cone-shaped kernel distributions of vibration acceleration signals, whichwere acquired from the cylinder head in eight different states of a valve train, were calculatedand displayed in grey images. Probabilistic Neural Networks ( PAW) was used to classify the imagesdirectly after the images were normalized. By this way, the problem of fault diagnosis for a valvetrain was transferred to the classification of time-frequency images. As there is no need to extractfeatures from time-frequency images before classification, the fault diagnosis process is highlysimplified. The experimental results show that the vibration signals can be classified accurately bythe proposed methods.展开更多
全光纤电流互感器(all-fiber optic current transformer,AFOCT)作为换流站内重要的测量设备,是保证直流系统安全稳定运行的基础。以某±800 kV换流站交流滤波器不平衡AFOCT测量数据异常导致断路器跳闸事件为例,首先,详细阐述了AFOC...全光纤电流互感器(all-fiber optic current transformer,AFOCT)作为换流站内重要的测量设备,是保证直流系统安全稳定运行的基础。以某±800 kV换流站交流滤波器不平衡AFOCT测量数据异常导致断路器跳闸事件为例,首先,详细阐述了AFOCT的基本工作原理,并推导得出其测量原理;其次,通过保护动作正确性分析、现场故障排查、现场验证、保偏光缆振动影响试验等方法深度研究分析,最终得出引起测量数据异常的根本原因,以及保偏光缆受振动影响的故障机理;最后,针对保偏光缆易受振动干扰导致测量数据异常问题,提出了具体的改进措施和工程建议,为后期换流站AFOCT的工程设计、现场施工验收、可靠性提升提供理论支撑。展开更多
文摘The cone-shaped kernel distributions of vibration acceleration signals, whichwere acquired from the cylinder head in eight different states of a valve train, were calculatedand displayed in grey images. Probabilistic Neural Networks ( PAW) was used to classify the imagesdirectly after the images were normalized. By this way, the problem of fault diagnosis for a valvetrain was transferred to the classification of time-frequency images. As there is no need to extractfeatures from time-frequency images before classification, the fault diagnosis process is highlysimplified. The experimental results show that the vibration signals can be classified accurately bythe proposed methods.
文摘全光纤电流互感器(all-fiber optic current transformer,AFOCT)作为换流站内重要的测量设备,是保证直流系统安全稳定运行的基础。以某±800 kV换流站交流滤波器不平衡AFOCT测量数据异常导致断路器跳闸事件为例,首先,详细阐述了AFOCT的基本工作原理,并推导得出其测量原理;其次,通过保护动作正确性分析、现场故障排查、现场验证、保偏光缆振动影响试验等方法深度研究分析,最终得出引起测量数据异常的根本原因,以及保偏光缆受振动影响的故障机理;最后,针对保偏光缆易受振动干扰导致测量数据异常问题,提出了具体的改进措施和工程建议,为后期换流站AFOCT的工程设计、现场施工验收、可靠性提升提供理论支撑。
