This paper reviews on the trends in extreme weather events induced by global climate change. The number of tropical cyclones (TCs) making landfall on Japan and their intensity show no discernible long-term trend in the past observation record, while the translation speed of TCs shows significant decline. The intensification of heavy rainfalls and extratropical cyclones are also confirmed. Recent simulation studies indicate that the global warming would increase the maximum wind speed and rainfall associated with the TCs. The intensification of extratropical cyclones, heavy rainfalls/snowfalls, tornados and lightning strikes are also predicted.

This paper proposes a decentralized charging and discharging control method of a battery energy storage system (BESS) to prevent the over-capacity of a pole transformer (Pole-Tr) in low-voltage (LV) distribution systems due to reverse power flow from the photovoltaic generation (PV) system. A distribution system operator (DSO) provides the charging/discharging parameters determined by using only the LV-distribution system configuration and the PV/BESS capacity to the customers and each BESS automatically controls the charging/discharging power according to the provided parameters. The charging parameter is defined in the relationship between the state-of-charge (SoC) and the charging threshold ε as the SoC-ε curve, and a total of three SoC-ε curves for the different objectives are prepared. In the charging phase, the BESS selects one SoC-ε curve every minute and determines the charging power based on the charging threshold ε and the present SoC. In the discharging phase, the BESS operates in the load-following discharging and SoC control discharging to adjust the SoC for the prevention of the over-capacity of Pole-Tr. The proposed method is tested on several types of LV-distribution systems, and the numerical simulation results demonstrate that the proposed method can prevent the over-capacity of Pole-Tr and maintain the high charging amount of BESSs.

In this study, high voltage is applied to the spherical electrode (diameter: 100mm), and the influence of the high electric field on the lithium ion battery (LIB) is verified. (1) Provide an air gap (20mm) only on the positive electrode of the LIB, and ground the negative electrode. When +10kV is applied, it is charged 15.8mV, and when -10kV is applied, it is discharged 10.7mV. The influence of deterioration on the LIB due to the high electric field was not observed. In addition, provide an air gap (10mm) on the both electrodes of the LIB. In both cases of ±10kV, the voltage of the LIB was charged and discharged by about 5mV. (2) When an air gap (20mm) was provided only on the positive electrode side of the LIB and a 10kVpp sine wave was applied at 50Hz, the LIB was slightly charged. (3) Provide an air gap (20mm) only on the positive electrode side of the LIB, and then apply +10kV (120h). As a result, the LIB was overcharged and the discharge capacity was greatly degraded. However, it is thought that there is almost no impact on the LIB if it is about several hours.

The lightning damage to wind turbine has worsened. The anti-lightning receptor, which grounds the lightning current, is very important to avoid corrupting the turbine blade. The receptor proposed which is triple layer (copper-graphite composite/pure copper/copper-graphite composite) showed very high thermal conductivity.