will occur when the frequency of train operation is low.
Expensive power conversion equipment is required to return regenerated power to the power supply network through a substation. This is not so efficient in reducing power consumption, given the high costs involved in the power conversion equipment. Therefore, it is desirable to install resistors to absorb the regenerated power at substations.
(2) Feed circuit protection is one of the most important and difficult problems for railway systems, for the following reasons.
(a) Long contact rails near running rails are subject to frequent accidents.
(b) Large feed currents flow through feed circuits at low voltages. Therefore it is difficult to distinguish accidental current from load currents. This becomes more difficult when power is being supplied in parallel from adjacent substations.
(c) Trains frequently turn load currents on or off. Load currents from multiple trains are superimposed in the feed current. Therefore, the feed current fluctuates rapidly. This makes it extremely difficult to protect the feed current.
(d) The direction of current changes at an ELRTS substation when it absorbs regenerated power. Therefore, protective measures shall be taken for current in two directions.
Based on past experience, railways in Japan useΔI type fault detectors as the main protection measure, over-current detectors as a backup measure, and link circuit breakers to detect accidents accidents adjacent substations in a parallel feed system. It is recommended that ELRTS substations have link circuit breakers.
(3) Substations and feed rooms shall be monitored and controlled from a power supply dispatch center. The center should be installed at the train operation control center to concentrate control conditions for power reception conversion, feed, and supply and demand, activity in event of accident train operations and passengers at stations.
7.5 Fare collection system
(l) Fare collection system out line
The system will generally employ a self-service, barriered fare collection system. The system will use a distance related graduated fare structure.
Automatic ticket vending machines and turnstiles operated by inserting tickets were planned for the fare collection system. Vending outlets of rail were recommended, as well as ticket sales at stations. Stored value cards were assumed. Bi-directional as well as single directional gates were recommended. Common ticketing with buses
