电力设备状态评估是状态检修的关键一环。为了解决电力设备健康状态评估结果准确性不高这一问题,该文设计了一种基于最优云熵-灰云证据的中高压断路器健康状态评估方法,该方法以云模型和证据理论为基本理论框架。选取适当的定性和定量...电力设备状态评估是状态检修的关键一环。为了解决电力设备健康状态评估结果准确性不高这一问题,该文设计了一种基于最优云熵-灰云证据的中高压断路器健康状态评估方法,该方法以云模型和证据理论为基本理论框架。选取适当的定性和定量评价指标建立综合评估体系;在灰云模型的基础上引入最优云熵,结合大数定理对所得隶属度进行二次处理最终确定状态区间隶属度,并将其作为证据理论的基本信度分配(Basic Probability Assignment,BPA);利用不确定系数对BPA进行二次更新;通过改进证据融合规则进行证据融合,所得结果转化为相应的健康指数使评估结果更为直观。实例分析表明,该方法能很好地处理评价过程中的模糊性及随机性,具有一定的参考价值。展开更多
A 3D Magnetohydrodynamics (MHD) arc model in conjunction with an arc move- ment model is applied to simulate the arc rotation as well as to solve its effect on the pressure in an auto-expansion circuit breaker. The ...A 3D Magnetohydrodynamics (MHD) arc model in conjunction with an arc move- ment model is applied to simulate the arc rotation as well as to solve its effect on the pressure in an auto-expansion circuit breaker. The rotation of the arc driven by an external electromagnetic force is simulated in the case with 200 kA of the short circuit current and 16 ms of arc duration. The arc rotating process and the speed of arc rotation have been obtained in the simulation. A comparison of the pressure in the expansion volume with and without an external magnetic field has been carried out based on the calculation results of two cases. The results of the simulation reveal that the arc rotation, which causes more energy exchange between the arc and its sur- rounding gas, can evidently bring about the pressurization in the expansion volume, which would contribute to more effective arc quenching at current zero and further reducing operation power.展开更多
The structure and operational principle on a new type reversing valve of hydraulic breaker are introduced. The nonlinear mathematic model and simulation model of the new type reversing valve are built. The dynamic sim...The structure and operational principle on a new type reversing valve of hydraulic breaker are introduced. The nonlinear mathematic model and simulation model of the new type reversing valve are built. The dynamic simulation research of the new type reversing valve is conducted. The effects of the system parameters on the working performance are researched systematically and deeply. The regular understanding on the motion of the reversing valve is obtained, which provides theoretical basis for the innovation and manufacturing of a new generation of hydraulic breaker reversing valve.展开更多
文摘电力设备状态评估是状态检修的关键一环。为了解决电力设备健康状态评估结果准确性不高这一问题,该文设计了一种基于最优云熵-灰云证据的中高压断路器健康状态评估方法,该方法以云模型和证据理论为基本理论框架。选取适当的定性和定量评价指标建立综合评估体系;在灰云模型的基础上引入最优云熵,结合大数定理对所得隶属度进行二次处理最终确定状态区间隶属度,并将其作为证据理论的基本信度分配(Basic Probability Assignment,BPA);利用不确定系数对BPA进行二次更新;通过改进证据融合规则进行证据融合,所得结果转化为相应的健康指数使评估结果更为直观。实例分析表明,该方法能很好地处理评价过程中的模糊性及随机性,具有一定的参考价值。
基金supported by National Natural Science Foundation of China (Nos.51177005 and 51477004)
文摘A 3D Magnetohydrodynamics (MHD) arc model in conjunction with an arc move- ment model is applied to simulate the arc rotation as well as to solve its effect on the pressure in an auto-expansion circuit breaker. The rotation of the arc driven by an external electromagnetic force is simulated in the case with 200 kA of the short circuit current and 16 ms of arc duration. The arc rotating process and the speed of arc rotation have been obtained in the simulation. A comparison of the pressure in the expansion volume with and without an external magnetic field has been carried out based on the calculation results of two cases. The results of the simulation reveal that the arc rotation, which causes more energy exchange between the arc and its sur- rounding gas, can evidently bring about the pressurization in the expansion volume, which would contribute to more effective arc quenching at current zero and further reducing operation power.
文摘The structure and operational principle on a new type reversing valve of hydraulic breaker are introduced. The nonlinear mathematic model and simulation model of the new type reversing valve are built. The dynamic simulation research of the new type reversing valve is conducted. The effects of the system parameters on the working performance are researched systematically and deeply. The regular understanding on the motion of the reversing valve is obtained, which provides theoretical basis for the innovation and manufacturing of a new generation of hydraulic breaker reversing valve.