Uninterruptible Power Supply Project

The Public Transport Authority of Western Australia (PTA)’s Rail Transport area is vast and continually expanding. This places a high importance on the reliability of the network, in which supply of power plays a critical role.

Power failures, dips and momentary losses contribute to causes of failures within signalling equipment, and station services. Signalling equipment on the existing urban railway is supplied from Western Power (WP) normally, with back up (emergency) power supplied from either a step down transformer (Emergency Supply Transformer, EST) or a generator, when normal supply is disrupted. The change over from WP supply to emergency supply results in a momentary interruption of power supply to signalling equipment which consequently results in signals displaying a red aspect.

The power supply to the system feeds a signalling distribution board that supplies step up (240/600V) and step down (240/110V) signalling transformers. The 240/600V transformers are responsible for maintaining supply to signalling equipment. The 240/110V transformer is responsible for the relays inside the relay room and in some cases may feed some signalling loads on the tracks (near the relay room).

The no-break power supply or uninterruptable power supply (UPS) will carry the load at all times and during transition between WP, a generator or a Ferromagnetic power conditioner (fed from the EST).