Nobuhiko Itaya

Cooperative control of reactive power of distributed PV systems to suppress voltage of distribution line along railroad track

There are a lot of potentials to install photovoltaic panels along the railroad track and some systems have been already realized in Japanese railway network. If a lot of PV systems have installed along the railway premises in the future, the generated power has to be transmitted to the station for the self-consumption because the electric loads along the railroad track between the stations are, in many cases, small. To be cost effective, simple cooperative reactive power control of power conditioner for distribution line voltage control to realize inverse backflow from PV panels to station is required, proposed and tested in the practical trackside solar system. The results of the cooperative reactive power control by two PV-PCSs are shown in this paper.

Development of Centralized Voltage Control System for Distribution Systems

This paper proposes a centralized voltage control system for distribution system to meet the impact of PV growth. The system consists of a server machine at control center and many field devices like voltage regulators, line switches with sensor to measure power flow and voltage, and Information and Communication Technologies (ICT) network under Smart Grid paradigm. The system gathers measurement values from switches through the ICT network and chooses the best voltage profile and voltage regulators condition to achieve the profile with use of our advanced Optimal Power Flow. The test results at our Smart Grid facilities with 4MW photovoltaic generators are also given to prove the effectiveness of the developed system.

Disconnection detection method for power distribution lines using smart meters

For future power outage management of a power distribution system, a smart meter is expected to be used. Disconnection of a high-voltage power distribution line during a power outage runs the risk of a major disaster, so it needs to be detected quickly. In this paper, we describe a power outage management system developed as a part of an in-house smart grid demonstration test for detecting disconnections of highvoltage power distribution lines. Then we propose and validate a disconnection detection method that does not need information of connection phases of pole transformers.