Traditionally, there are close relation between load dispatching operation of power system and meteorological phenomena, such as demand fluctuation and temperature, hydro power generation fluctuation and precipitation, and faults and extreme weather like lightnings or typhoon.  Load dispatching operators of power system, by gathering and utilizing available meteorological information, continuously monitor the constantly changing power demand and the power plant operation level to perform power supply demand management and power system operation.  Considering the evolving environment of the load dispatching operations, our R&D Investigation Committee examined the relation between load dispatching operation and meteorological information, the collection method and utilization of meteorological information, and the changes in load dispatching operation caused by the further introduction of renewable energy. Moreover, we have summarized possible issues and future visions on the expansion of renewable energy.

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In recent years, a large amount of photovoltaic (PV) generations have been installed in power systems. However, the power output from the PVs is random and intermittent in nature. Therefore, the PV generations pose many challenges to the power system operation. To estimate the impact of these issues on the power system operation, we propose optimal weekly demand and supply simulation method considering a large penetration of photovoltaic generations. In this paper, a study for operation scheduling method considering optimal hot reserve capacity is presented. The effectiveness of the proposed method is shown by using Monte Carlo simulation.

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In this paper, we propose a multi-agent based electric power interchange method between micro-grids (MGs). The proposed multi-agent system consists of eight types of agent: single micro virtual power plant agent (MVPP), several Micro Grid controller agents (MGCs), several Load agents (LAGs), several gas-turbines (gas-engine) agents (GAGs), several photovoltaic generation agents (PVAGs), several wind-turbine generation agents (WTAGs), several battery agents (BAGs), and single grid agent (GridAG). In the proposed system, MVPP plays as an important role, which facilitates the electric power exchange between MGCs. From the simulation results, it can be seen the proposed multi-agent system could improve the load factor and reduce the MG operation cost.

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PV system recently attracts much attention on the back of environmental problems, antinuclear power movements and energy problems. Therefore, a large scale introduction of PV system is expected in the near future. On the other hand, a lot of PV systems connected to the power system bring on some problems. For example, a system voltage often drifts from the norm when the reverse power flow increase. Accordingly, it is necessary to perform an optimal system operation in order to utilize a solar energy to the maximum by installing energy buffers, e. g. storage batteries. Especially, the forecast information i.e., the reliability as well as predicted solar irradiance is essential for the effective operation. In this paper, we propose a way to estimate the prediction interval of the solar irradiance as an index of reliability by using Just-In-Time Modeling (JIT Modeling). We consider the accuracy of the prediction interval under many conditions and derive the high-precision estimation method. In addition, we also talk about the future outlook of this study.

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From the global environmental viewpoint, distributed power systems using renewable energy source, such as solar power, wind power, and water power attract much attention. Photovoltaic (PV) system using solar power has a little resource constraint and can be installed easily on the roof of house. Therefore, PV system has been and will be introduced widely. However, in case many PV systems are installed in consumers, the deference of installed PV capacity may cause the load unbalance. In such a case, the difference of the line currents flowing along middle / high-voltage lines can be increased and three-phase voltage unbalance may appear due to the line impedance.  In this paper, a distribution transformer using three-phase to single-phase matrix converter with an AC inductor is proposed to suppress three-phase voltage unbalance. The AC inductor is used for compensation of single-phase power pulsation at any load conditions and either direction of power flow. The proposed method is verified by the simulation with MATLAB/Simulink. In this simulation, the resistive loads and the reactive loads are assumed as the loads in low-voltage line. Reverse power flow from PV systems is represented by a current source with power factor 1.0. Control strategy and simulation results are shown in this paper.

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From an environmental viewpoint, when carrying out internal arc tests on SF₆-insulated power equipment, it is necessary to prevent SF₆ from being released into the atmosphere or to replace SF₆ with air in accordance with IEC standards. However, the pressure rise and the thermal of the hot gas exhausted during arcing when testing in air are still considerably different from those for testing in SF₆. Thus, it is necessary to propose a specific procedure to replace SF₆ with air and to select appropriate parameters for the tests. Therefore, it is desirable to clarify the equivalent conditions causing these phenomena both experimentally and analytically. In this paper, we describe the effect of the charged gas pressure in a closed container on the pressure rise due to air and SF₆ arcing and the ratio of the arc energy to the energy contributing to the internal pressure rise (k_p) from an experimental viewpoint. Additionally, to research the energy balance resulting from SF₆ arcing in the container, the energy balance is discussed on the basis of chemical reactions, radiation, and the melting and vaporization of the electrodes. It is found that the maximum pressure rise increases for both gases upon increasing the gas pressure from 0.1MPa to 0.4MPa. Subsequently, good agreement with the energy balance was obtained under reasonable assumptions by taking account of the energy components related to the chemical reactions, radiation, and the melting and vaporization of the electrodes. The ratio of the radiation energy loss to the total consumption energy increased upon increasing the charged gas pressure.

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Fuel cell as one of co-generation system and battery energy storage system can be used as power sources in an isolated power system in complex housing at blackout. This paper reports study results on this isolated power system. Simulation models are developed and the results are compared with measured values of active power, reactive power, and voltage. Good agreement between them is obtained. In this analysis it is found there is stability limit in such inverter power source operation. The stability limit is expressed by a short circuit power ratio that is similar expression in the conventional ac system. A nonlinear load switching is also studied to show stable operation furthermore.

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A model of a wind turbine tower with an internal conductor for lightning simulation by circuit analysis method is proposed in this paper. The tower is represented by a frequency-dependent pipe-type cable replacing the parameters of its earth return mode. The parameters of the other modes can be obtained by any conventional method, such as SEMLYEN SETUP with CABLE PARAMETERS installed in the Electro-Magnetic Transients Program (EMTP). The parameters of the earth return mode are obtained from a result calculated by Finite-Difference Time-Domain (FDTD) method taking into account the vertical configuration of the wind turbine tower. The simulated voltages of the tower and internal conductor by the proposed model agree with measured results of a small scale model. Numerical lightning surge simulation on a wind turbine tower, which cannot be perfectly represented by FDTD method, can be carried out by the proposed method.

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This letter proposes a new method for Daily Peak Load Forecasting. Non-linear correction T method, which is improved from T method of the MT system, is applied to this method. By proposed method, the predictive precision is improved in comparison with the T method. Furthermore, frequency that actual value exceeds predicted value becomes less than conventional method.

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I am the chemistry girl. I discussed and took local issue as a big theme. And I focused on problem of solved in Lake Shinji. Discussing how to use solved.  I took it as a electric batteries.  From now I am going to explain the experiment I did.

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[in Japanese]

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