Hirotaka Takahashi

Effect evaluation of Li-ion battery for regenerative energy utilization in traction power supply system

Two Lithium ion battery systems have already installed at practical traction substations, HAIJIMA SS and OKEGAWA SS, to utilize regenerative energy in d.c. 1.5kV traction power supply system of East Japan Railway Company. In this paper, the effect of energy storage system for energy saving by making use of regenerative energy is evaluated in detail. According to our experiences, the annual effects of energy storage systems at HAIJIMA SS and OKEGAWA SS are 400MWh/year and 600 or 700MWh/year, respectively.

Lithium-ion battery installation in traction power supply system for regenerative energy utilization Initial report of effect evaluation after half a year operation

Previously, some energy storage systems were installed to compensate for voltage drop and to avoid regenerative brake cancelation in d.c. 750V and 1.5kV traction power supply system in Japan. The fly wheel and Lithium-ion (Li-ion) battery, nickel metal hydride (Ni-MH) battery and electric double layer capacitor (EDLC) were used as a storage device. In East Japan Railway Company, Li-ion battery system was installed at HAIJIMA Substation (SS) on Ome Line and started operation on February 20th, 2013. It is the first application of the energy storage system mainly not for voltage drop compensation but for regenerative energy utilization. In this paper, the effect of Li-ion battery system installed at HAIJIMA SS is evaluated based on the measured data during the practical operation and it is shown that it contributes to more than 5% reduction of total traction power supply at HAIJIMA Substation. The future plan of energy storage application is also mentioned.

Lithium ion battery application in traction power supply system

Technology development has been promoted aiming for an environment-friendly traction power supply system for railways. Among other things, a stationary energy storage system using lithium ion batteries for hybrid cars has been put into practical use since 2007. This device temporarily stores regenerative power generated from an train when it is stopped and the power is able to be applied for energy saving, measures against regeneration canceled and compensation for a voltage drop. The implementation planning for a stationary energy storage system (SESS) has been popular in recent years. The implementation of the SESS at railway companies can contribute to the reduction in the global warming gas emissions.

Development of emergency self-running train for energy utilization in Stationary Energy Storage System

The SESS (Stationary Energy Storage System) using a lithium-ion battery has been introduced and operated both in Japan and overseas for the purpose of taking measures for regeneration cancellation, voltage drop compensation and energy conservation. Considering the battery characteristics, the SESS, which can store sufficient electric energy, is applicable for emergency self-running of trains during a wide-area power failure in the event of major disaster. Various research and development projects using the SESS were carried out and the demonstration test was conducted. The summary of the research and development projects and the result of the demonstration test are reported below.

Peak-shift method for reducing facility cost of distribution system

Because of the low cost of electricity, when the concentration of electric vehicle charging and the running of the home appliances during certain hours of the day, the peak load of a distribution substation feeder or pole transformer increases. In general, when the peak load increases, electric power companies change the connection of electrical distribution lines or replace equipment such as distribution substation feeder or low-voltage transformer to high-capacity one. However, electric companies face higher costs when they do this. We developed a new peak shift, ‘combined method’, that can be used to reduce the load peak both of the distribution substation feeder and low-voltage transformers. This method can reduce the need to replace equipment in distribution systems and also reduce the cost of electric power companies.

The function development for emergency train running by battery application in traction power supply system

The SESS(Stationary Energy Storage System) using a lithium-ion battery has been introduced and operated both in Japan and overseas for the purpose of taking measures for regeneration cancellation, Voltage drop compensation and energy conservation. Considering the battery characteristics, the SESS, which can store sufficient electric energy, is applicable for emergency running of trains during a wide-area power failure in the event of major disaster. Various research and development projects using the SESS were carried out and the demonstration test was conducted. The summary of the research and development projects and the result of the demonstration test are reported below.