Performance indices of stationary energy storage in the traction substations of the Moscow Metro

It is shown that full-scale application of regenerative breaking in electric trains with asynchronous motors is has a large effect on electric-power efficiency in the traction power-supply system of the Moscow Metro. Particular lines of the Moscow Metro were considered (Filevskaya, Arbatsko-Pokrovskaya, Butovskaya, Kol’tsevaya), where trains are equipped with asynchronous motors of 81–740/741 Rusich series. The lines are able to save up to 10–12% of the traction energy in the regenerated energy. It is suggested to use a system of stationary energy storage to improve the efficiency of regenerative braking. A stationary uncontrolled storage system based on storage modules produced by the Russian company Elton was selected from among the multiple existing types of storage systems. A scheme of stationary energy-storage system for use in the traction power-supply system of the Moscow Metro is described. Electrotechnical characteristics of the storage system and its performance features and functionality are presented. The power indices of the stationary energy-storage system were measured experimentally for normal operation at a traction substation of the Filevskaya line of the Moscow Metro over several months. Maximum levels of the regenerated energy and the cycle and efficiency ratio were determined. Long-term monitoring of the normal operation confirmed high reliability of stationary energy storage. Every system, including the switching elements; diagnostic and control systems of storage modules; and control and signaling systems, including those at the dispatching office; operated in a failsafe fashion. The stationary energy-storage system exhibited more positive effects, such as stabilization of voltage at the traction substation bus and possible lower rated power capacity of a traction substation as an effect of a smooth power consumption. It is also possible to bring a train containing passengers from a tunnel to the nearest station in case of external power-supply failure. The correlation between the theoretical calculations and the experimental measurements is displayed.