Power distribution equipment is used to supply electricity to consumers, and has been upgraded primarily to improve reliability and efficiency. However, the spread of energy-saving equipment and declining population will lead to a saturation trend in electricity demand, which will reduce the opportunities for upgrading equipment. Therefore, when equipment is upgraded, it must be upgraded to equipment that can be used for a longer period of time. In addition, due to labor shortages, when upgrading equipment, it is necessary to upgrade to equipment that can be upgraded with minimal effort. In order to respond to these needs, it is important to understand the history of improvements in power distribution equipment. Therefore, the technical transitions of power distribution equipment and future-oriented technology trends are summarized in the Institute of Electrical Engineers of Japan Technical Report (No. 1548). This section introduces the technical transitions of major equipment (concrete poles, electric wires, cables, and pole-mounted transformers).

In recent years, wind power generation has been promoted as a countermeasure to global environmental problems. However, the introduction of many wind power generators into the power system may cause system frequency fluctuations. This paper proposes a control method to reduce system frequency fluctuations by using the Rotor Kinetic Energy (RKE) of a Variable Speed Wind Turbine (VSWT). When the frequency falls, this method suppresses fluctuations by consuming RKE to increase VSWT power generation, and when it rises, it decreases VSWT power generation by accumulating RKE. The effectiveness of this method is confirmed through simulations using PSCAD/EMTDC.

The voltage regulation and power loss reduction are important issues in distribution systems with more integration of variable renewable energy sources such as photovoltaic (PV). It is effective to flexibly change the network configuration by using switchgears in order to mitigate voltage fluctuation by decreasing the distribution power loss. Here, it should be needed to avoid overloading on distribution lines even with uncertain power flow changes caused by fluctuations of PV output and loads. Hence, this study developed a probabilistic optimization method for network reconfiguration, supposing the monitoring data measured by sensors with Phasor Measurement Units (PMUs) are available. The proposed method consists of quasi Monte Carlo simulation and Tabu search for probabilistic state estimation and network reconfiguration, respectively.

It is hoped that the power system will be operated safely and economically. Optimal Power Flow (OPF) is being studied in order to find a more economical operational point while ensuring safety. In our laboratory, we have been studying TSCOPF (Transient Stability Constrained Optimal Power Flow) after the assumed contingency by adding the magnitude of the phase angle with respect to the center of inertia to the constraint condition. Currently, the combination of the interior point method and the numerical discretization method is widely used to solve TSCOPF. Since the TSCOPF with numerical discretization is a large nonlinear programming problem, and there is a problem that the calculation time becomes long. In our previous research, we have reduced the computation time for a single contingency TSCOPF using the Reduced Space Technique. In this study, we propose the multi-objective TSCOPF with multiple contingencies using Reduced Space Technique to reduce the computational burden. The proposed method has been implemented and applied to the IEEJ WEST 30 test system to demonstrate the effectiveness of the proposed method.

Diagnostic for state of health is key technology for renewable energy development using reuse battery which has a performance variation. A proposal method, based on current sharing ratio in parallel, determines whether the capacity, as the measure of battery performance, is higher than other stacks. This method gives the health of the stack to be determined during system operation using only inexpensive current sensors, without the use of external devices or expensive measurement equipment as in the conventional method.