ABB has developed a specialist retrofitting service for HV surge arresters that provide a cost-effective route to update outdoor substations to modern specifications.
ABB’s surge arrester retrofit service enables the transformer circuits in outdoor high voltage substations, typically up to 400kV, to be upgraded to a high level of protection against the damaging over-voltages created by lightning strikes. This provides an efficient and cost-effective method for increasing the security and reliability of the substation operation and minimising interruptions to the power supply delivered to consumers.
The retrofit service utilises ABB’s well-proven Pexlim surge arresters. These use zinc oxide (ZnO) blocks in a composite silicone rubber housing that is extremely resistant to environmental pollution and vandalism. The material offers the very highest safety levels since it is self-extinguishing and will fail safely rather than exploding when over-stressed.
In new substation projects, the additional cost and complication of installing surge arresters is relatively small. However, retrofitting surge arresters to existing installations is much more challenging, as suitable overhead mounting gantries, typically of a ‘goalpost’ design 20m high and 21m in span, have to be transported on site and erected by crane. There may also be a need for additional foundation works and possibly piling.
Tom Smith, ABB project manager responsible for the surge arrester installation service, says: “Our surge arrester retrofit has refined its skills in 39 installations already completed successfully for UK customers. Having experience of just about every possible permutation enables us to provide very fast turnaround, with installation usually completed within a week.
“A key aspect of the service is the careful advance planning and coordination we provide to ensure that the installation work ties in with planned outages, so that we can minimise potential disruption to the substation operation. And we have developed safe working methods that enable us to carry out a significant proportion of the civil works, even piling for foundations, without having to take an outage.”