Fault Current Interrupting Arcing Horns (FCIAH) for 77kV overhead transmission lines are a countermeasure against lightning damage which break fault current within an AC cycle, and greatly contribute to reducing power interruption and instantaneous voltage drop. This paper has presented that reducing the number of interruption core from 2 to 1 reduced the cost of FCIAH, and changing the structure of interruption core resulted in reducing the interruption time from 1.0 cycle to 0.5 cycle and improving the current value from 10kA to 31.5kA when the interruption core was damaged.
This paper presents the progress of an energy economic model, named Dynamic Multi-Sector Energy Economic model (DMSEE) and suggests optimum power generation mix in Japan in 2050. This model is based on general equilibrium models maximizing utility function of consumptions, and elaborates electricity sector of energy sectors with very high time resolution. Therefore, this model is able to suggest the best solutions from both energy and economic viewpoints with considering relationship between them. According to calculation results, nuclear power, solar PV (Photovoltaics) and storage equipment play an important role for sustainable energy supply and reduction of carbon dioxide (CO2). And, although increases of investment for such technology prompt growth of economy, social utility declines. Therefore, we need to be careful to introduce policy such as CO2 emissions tax.
The authors constructed a micro grid by interconnecting multiple power sources. Low cost cooperative operation method of PV and DG was developed. The proposed method was evaluated by time axis simulation. It is possible to stably supply electric power following various load fluctuations at the factory. Furthermore, the voltage and frequency quality was verified by acquisition of long term actual measurement data. The results of verifying the fuel consumption reduction amount are described. It is possible to minimize the installed capacity of storage batteries, reactive-power compensators, for frequency and voltage stabilization by introducing renewable energy.
Characteristics of PTFE ablation due to SF6 arc exposure was studied to predict the ablated mass of PTFE nozzle in high-voltage circuit breaker. From the measurement of the ablated mass, the predominant factor of the PTFE ablation was revealed as a radiation power of SF6 arc. Subsequently, the radiation power absorbed in PTFE was formulated on the basis of the radiation transfer property and the arc physics. The formulation for the prediction of the PTFE ablated mass was established with the formulated radiation power and the measured masses. Finally, the validity of the PTFE ablated mass prediction was shown from the results of the error verification with the measured masses.
This paper describes an experimental study on multiphase flashover in 6.6kV medium voltage line in Japan. The experiments simulate a direct lightning strike to the top of concrete pole of the distribution line. A flashover occurs from a metallic arm to a phase wire. Most of single-phase flashover in non-grounded lines is naturally recovered due to low fault current. Therefore, a study on multiphase flashover is very important to establish a rational lightning protection design for medium voltage lines. Influences of parameters such as the combination of insulators and crest value of applied voltage on the multiphase flashover are discussed. A solid core insulator and a pin type one, which are normally used in 6.6kV lines in Japan, are used in the experiments. Measurements of fifty percent flashover voltage and voltage-time characteristic are carried out in this paper. This paper discusses an influence of different insulation level insulators on the reduction of two-phase flashover using the experimental results.
At Syowa Station in Antarctica, the majority of necessary heat and electric energy is currently supplied by fossil fuels transported from Japan. In the future, it is expected that the power consumption will increase at Syowa Station. Therefore, utilization of solar power generation and wind power generation is being studied. However, these output fluctuations are severe, and if they are connected to a small electric system of Syowa Station, adverse effects such as frequency fluctuation are concerned. Application of a storage battery is considered as a countermeasure against this, but it is worried about performance decline at low temperature, so it is necessary to keep the temperature. The purpose of this research is to develop simple heat retention technology for storage batteries used at Syowa Station. In this paper, the measurement result of surface temperature of a nickel - metal hydride battery wrapped with a heat insulation material and a thermal model are shown.
ZnO materials exhibit excellent nonlinear electric characteristics and the particles of ZnO with different sizes are also used as fillers in composite material. In this paper, the durability tests were conducted with direct measurements on single ZnO particles (∼100μm), and the change in the electric characteristics was investigated. As a result, varistor properties were found in ZnO micro particles. Varistor voltage became constant without correlation with the number of measurements, but the nonlinear coefficient tended to decrease in a very small range.