In conventional cumulant method of probabilistic load flow (PLF), random generator outages are usually simulated by discrete distributions of nodal power injections, but that will lead to significant error in AC load flow model. An improved PLF method base on AC model is proposed in this paper, which considers random generator outages and loads uncertainties. Cumulant and Gram-Charlier series expansion were applied to deal with the random variations of loads, instead of convolution calculations. According to the characteristics and focused aspects of power grid, certain generators were selected to form event group of generator outages and each event was analysed by exact load flow.Then total probability theorem was introduced to obtain the probabilistic distributions of node voltages and line flows that considered random factors of loads and generators.The case study of IEEE 39-bus system shows that the random generator outages remarkably affect the probabilistic distributions of state variables. The proposed method can avoid the error caused by generator outages in conventional cumulant method. Furthermore, the result of proposed method is consistent with that of Monte Carlo simulation, while computation speed is much faster.

Internalization of environment cost assessment measures the level of an enterprise’s environmental cost internalization. It’s also the basis of carrying out recycling economic in an enterprise. First of all, we established an environmental cost analysis model, in line with which we build the internalization of environment cost index system. Then adopting comprehensive evaluation method basing on fuzzy neural network can help us assess the effect brought by the internalization of environment cost. Finally, we conducted an experiment which comparing fuzzy neural network with the fuzzy evaluation of environment cost objectively. So we can think it’s an effective method.

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Abstract-With the growing demand for energy of China, oil and gas storage safety will directly influence the development of Chinese economy, The use of salt cavern storage of oil and gas because of its unique advantages has become an important way for oil and gas storage, which has shown a good application effect in many countries. China is abundant in underground rock salt resources and is provided with geological conditions of basic construction of salt cavern storage. In order to exploit salt cavern for oil and gas, in the construction and management process of salt cavern, people must performed shape measurements on the salt cavern, and then analyzed the measuring data processing. In this paper, by the German SOCON company salt cavern surveying data as the research object, in-depth analysis of the record format salt cavern surveying data, using C# language programming to achieve the salt loading data, establishing salt cavern data application system, and realizing three-dimensional model of salt cavern exhibition, and also put forward a method to calculate the volume of the cave. To improve the security of the salt cavern gas storage, pave the way for the further study of salt cavern gas storage optimal shape.

Monthly maintenance schedule has an important guiding significance to day ahead maintenance arrangement. However, the current management of monthly maintenance schedule is short of quantitative analysis methods. Consequently it can’t effectively take the security risk that may exist under monthly maintenance schedule. This paper presents a static security checking method for monthly maintenance schedule. First, established the monthly power grid network model based on the realtime model and device state changes, including the commissioning and decommissioning devices and maintenance devices. Next, the month-contract energy was decomposed to every day and every hour, then combined with monthly load forecast and maintenance schedule, the power system typical operation modes were generated automatically. Finally, quantitative assessment of monthly maintenance schedule was completed by power flow calculation, security analysis and evaluation indexes, including load supply adequacy and equivalent generation capacity loss. This method is instructive for monthly maintenance arrangement and its feasibility is proved by practical application.