Verification tests of electric double-layer capacitors for static energy storage system in DC electrified railway

The energy storage system solves the problem of rising energy costs by reducing primary energy consumption. Without a static energy storage system, the energy generated by a braking vehicle would be simply converted into waste heat by its braking resistors if no other vehicles are powered simultaneously. This greatly reduces primary energy demand in the substation and realizes voltage drop compensation. The environment also benefits through a corresponding reduction in CO₂ emissions. A wide range of large-scale electric double-layer capacitors (EDLC) rapidly charged and discharged, offer durability, maintenance-free features, low-pollution, and high efficiency levels have been recently developed. With this background, two energy storage systems were built for DC 600 V and DC 750 V, and verification tests were conducted. The reliability of the energy storage system was also confirmed by using DC 1,500 V laboratory system. These test results proved to be used as a guideline for actual applications to DC 1,500 V or DC 3,000 V railway systems.