One function for approximating pulse quantities in high voltage technique is presented in this paper. The function derivative, its integral, as well as its Laplace and Fourier transform are obtained analytically. Inte...One function for approximating pulse quantities in high voltage technique is presented in this paper. The function derivative, its integral, as well as its Laplace and Fourier transform are obtained analytically. Integral transformations of the pulse function are needed in frequency domain calculations of lightning induced effects in the case of a lossy ground. The pulse function having adequately chosen parameters is applied in lightning discharge modeling for lightning electromagnetic field calculation, and the results are in agreement with the results from literature. The choice of function parameters is based on their influence on the pulse waveshape which is presented in the paper. Numerical results for the Fourier transform are presented for different usually used pulse functions. The advantages of this function are simple choice of its parameters according to the desired waveshape characteristics and analytical solutions useful in lightning discharge modeling, electromagnetic field computation and induced effects calculations.展开更多
The upward lightning(UL) initiated from the top of tall buildings(at least above 100 m) is a type of atmospheric discharge. Currently, we understand the nature of the UL from ground observations, but the corresponding...The upward lightning(UL) initiated from the top of tall buildings(at least above 100 m) is a type of atmospheric discharge. Currently, we understand the nature of the UL from ground observations, but the corresponding theoretical research is lacking. Based on an existing bidirectional leader stochastic model, a stochastic parameterization scheme for the UL has been built and embedded in an existing two-dimensional thundercloud charge/discharge model. The ULs simulated from the experiments with two-dimensional high resolution agree generally with the observation results. By analyzing the charge structure of thunderstorm clouds, we determined the in-cloud environmental characteristics that favor the initiation of conventional cloud-to-ground(CG) flashes and analyzed the differences and similarities of some characteristics of the positive and the negative UL. Simulation results indicate that the positive ULs are typically other-lightning-triggered ULs(OLTUL) and are usually a discharge phenomenon between the ground and the lower positive charge region appearing below the main middle negative charge region. The effect of the previous in-cloud lightning(IC) process of space electrical field provides favorable conditions for the initiation of a positive UL. Its entire discharge process is limited, and the branches of the leader are fewer in number as its discharge is not sufficient. A negative UL is generally a discharge phenomenon of the dipole charge structure between the ground and the main negative charge region. The lower temperature stratification and the sinking of the hydrometeors typically initiate a negative UL. Negative ULs develop strongly and have more branches. The OLTUL is initiated mainly during the development stage of a thunderstorm, while the self-triggered UL(STUL) is initiated mainly during the dissipation stage of a thunderstorm.展开更多
In the context of the integrated development of artificial intelligence and the power industry,the State Grid has carried out in-depth research on the research and development and application of the Guangming Power mo...In the context of the integrated development of artificial intelligence and the power industry,the State Grid has carried out in-depth research on the research and development and application of the Guangming Power model.The model is based on the knowledge of the power industry,cognitive computing as the core,and knowledge service as the goal,and has the characteristics of large sample,large calculation,large parameters,large knowledge,and large tasks,providing important support for the intelligent transformation of the power industry.This study focuses on the efficient operation of Guangming Power large model,builds a trinity operation system of“model iterative optimization,sample full-process governance,and computing power resource collaboration”,and drives the continuous improvement of model capabilities and compliance development through a two-level collaboration mechanism.With the goal of“building a strong and excellent Bright Power Large Model”,the study clearly states that it is necessary to accelerate the construction of a two-level collaborative operation system,and promote model iterative optimization,capability evaluation,service monitoring and compliance review on a regular basis.At the same time,focusing on the whole process of R&D and application of large and small models,starting from four aspects:computing power planning and layout,allocation and scheduling,adaptation and optimization,monitoring and analysis,strengthening the application monitoring and analysis of two-level intelligent computing centers,and building an efficient computing power resource application and supply system to continuously improve its operation and service capabilities.展开更多
文摘One function for approximating pulse quantities in high voltage technique is presented in this paper. The function derivative, its integral, as well as its Laplace and Fourier transform are obtained analytically. Integral transformations of the pulse function are needed in frequency domain calculations of lightning induced effects in the case of a lossy ground. The pulse function having adequately chosen parameters is applied in lightning discharge modeling for lightning electromagnetic field calculation, and the results are in agreement with the results from literature. The choice of function parameters is based on their influence on the pulse waveshape which is presented in the paper. Numerical results for the Fourier transform are presented for different usually used pulse functions. The advantages of this function are simple choice of its parameters according to the desired waveshape characteristics and analytical solutions useful in lightning discharge modeling, electromagnetic field computation and induced effects calculations.
基金supported by the National Key Basic Research Development Program of China (Grant No. 2014CB441403)the National Natural Science Foundation of China (Grant Nos. 41175003 & 41475003)
文摘The upward lightning(UL) initiated from the top of tall buildings(at least above 100 m) is a type of atmospheric discharge. Currently, we understand the nature of the UL from ground observations, but the corresponding theoretical research is lacking. Based on an existing bidirectional leader stochastic model, a stochastic parameterization scheme for the UL has been built and embedded in an existing two-dimensional thundercloud charge/discharge model. The ULs simulated from the experiments with two-dimensional high resolution agree generally with the observation results. By analyzing the charge structure of thunderstorm clouds, we determined the in-cloud environmental characteristics that favor the initiation of conventional cloud-to-ground(CG) flashes and analyzed the differences and similarities of some characteristics of the positive and the negative UL. Simulation results indicate that the positive ULs are typically other-lightning-triggered ULs(OLTUL) and are usually a discharge phenomenon between the ground and the lower positive charge region appearing below the main middle negative charge region. The effect of the previous in-cloud lightning(IC) process of space electrical field provides favorable conditions for the initiation of a positive UL. Its entire discharge process is limited, and the branches of the leader are fewer in number as its discharge is not sufficient. A negative UL is generally a discharge phenomenon of the dipole charge structure between the ground and the main negative charge region. The lower temperature stratification and the sinking of the hydrometeors typically initiate a negative UL. Negative ULs develop strongly and have more branches. The OLTUL is initiated mainly during the development stage of a thunderstorm, while the self-triggered UL(STUL) is initiated mainly during the dissipation stage of a thunderstorm.
文摘In the context of the integrated development of artificial intelligence and the power industry,the State Grid has carried out in-depth research on the research and development and application of the Guangming Power model.The model is based on the knowledge of the power industry,cognitive computing as the core,and knowledge service as the goal,and has the characteristics of large sample,large calculation,large parameters,large knowledge,and large tasks,providing important support for the intelligent transformation of the power industry.This study focuses on the efficient operation of Guangming Power large model,builds a trinity operation system of“model iterative optimization,sample full-process governance,and computing power resource collaboration”,and drives the continuous improvement of model capabilities and compliance development through a two-level collaboration mechanism.With the goal of“building a strong and excellent Bright Power Large Model”,the study clearly states that it is necessary to accelerate the construction of a two-level collaborative operation system,and promote model iterative optimization,capability evaluation,service monitoring and compliance review on a regular basis.At the same time,focusing on the whole process of R&D and application of large and small models,starting from four aspects:computing power planning and layout,allocation and scheduling,adaptation and optimization,monitoring and analysis,strengthening the application monitoring and analysis of two-level intelligent computing centers,and building an efficient computing power resource application and supply system to continuously improve its operation and service capabilities.
