Protecting trackside equipment from power surges

Edited by the Engineeringtalk editorial team Jan 21, 2002

A new range of Surge Suppressors are specifically designed to protect railway trackside applications from potential damage caused by surges in the power supply and local lightning strikes

Power quality management specialist Advance-Galatrek has unveiled its new StrikeSafe range of 650 Volt Transient Voltage Surge Suppressors (TVSS), specifically designed to protect railway trackside applications such as signalling units from potential damage caused by surges in the power supply and local lightning strikes.

Advance-Galatrek's years of experience of operating in this critical sector have demonstrated that spikes and surges caused by variations in the overhead traction supply can have a detrimental effect on the reliability of sensitive signalling apparatus.

This can potentially lead to serious problems and, ultimately, the likelihood of a catastrophic equipment failure.

Because failed signals automatically default to danger, this can cause an undesirable increase in the number of SPADs (Signals Passed at Danger).

The standard 25,000 Volt traction supply is subject to variable loads, caused primarily by intermittent connections between the overhead line and the pantograph fitted to electric locomotives.

Inevitably, this causes transient surges and spikes to occur in the 650 Volt trackside power supply that feeds ancillary components such as signalling equipment.

This, in turn, leads to excessive wear and early failure, due to transient waveform damage.

Advance-Galatrek's latest StrikeSafe range of TVSS devices features a unique patent-pending matrix design that offers far better levels of surge protection than other competitor devices.

Matrix technology means that StrikeSafe units will continue working in accordance with their specification even in the event of individual component failure.

StrikeSafe units also make use of Advance-Galatrek's innovative Silicon Avalanche Diode (SAD) technology, making them much more responsive to the rapid voltage surges that comprise the leading edge of a transient infected waveform.

The SAD componentry can clamp voltage surges much more effectively than conventional Metal Oxide Varistor (MOV) based surge suppressors.

However, because SADs alone cannot dissipate as much total transient energy as MOVs, StrikeSafe deploys a combination of SAD and MOV technology, helping to provide a rapid response to voltage transients, combined with the greatest possible surge protection.

As well as providing effective protection against locomotive generated transients, StrikeSafe represents an ideal solution to the dangers caused by a lightning strike.

Statistics demonstrate that an average lightning hit can cause a surge of 10000 Volts in adjacent equipment.

In these circumstances, StrikeSafe is designed to provide the maximum possible protection against catastrophic equipment damage and failure.

According to Leo Craig, Advance-Galatrek's Railtrack Customer Projects Manager, StrikeSafe represents the perfect answer to the problem of how to protect sensitive signal control telemetry equipment.

'Unlike many competitor units, the StrikeSafe TVSS range provides a bespoke solution to the question of how to achieve a stable output supply for signalling equipment.

Our TVSS devices are just one example of the diverse mix of products and services that Advance-Galatrek can offer the rail industry.

Together with our UPS, DC standby power systems, generators, voltage conversion and isolation transformers, control panels and switchgear, we can offer complete trackside power management solutions to Railtrack,' he said.