Modern high-speed rail traction systems exert heavy and complex loadings on supply grids. Usually, power is taken between two phases, thereby causing substantial imbalance between phases in networks originally not at all built for this kind of operation. Unless remedied, the result will be deterioration of power quality, not only harmful to the traction system itself, but also prone to spreading through the supply grid, disturbing other users of power in the same grid.
Furthermore, sagging and fluctuating catenary voltages may result from heavy and varying consumption of reactive power by locomotives. This must be addressed, too, by means of dynamic voltage support of catenaries, thereby maintaining heavy traction capability despite weak feeding, and without harmful voltage drops along the catenary.
In all these cases, time as well as money can be saved by implementing FACTS in existing systems rather than having to invest in costly and time consuming reinforcement of the railway feeding infrastructure such as building new transmission or sub-transmission lines, and/or building new substations and feeding points.
It is also worth mentioning that with FACTS in the system, adequate power quality can be achieved with in-feed at lower voltages than would otherwise be possible. This means, for example, that it may be sufficient to feed a railway system at 132 kV rather than at 220 kV or even 400 kV, which will of course enable a lower investment cost and in shorter time.
FACTS for railways comprises SVC, SVC Light® and Dynamic Energy Storage.
>> More about SVC and SVC Light
>> More about Dynamic Energy Storage
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