AC Electrical (Rochdale) LTD is now offering a thermal imaging survey as part of a comprehensive HV (high voltage) maintenance and inspection package for private electrical distribution networks up to 33kV. Using a self-contained, hand-held thermal imaging camera, the AC Electrical team can carry out a thermal sweep of an electrical installation to identify temperature differences caused by changes from normal operating conditions or hotspots which can indicate a developing problem such as a loose or corroded connection.
Thermal imaging is most useful for the inspection of cables and unenclosed low voltage switchgear, as well as visualising oil circulation in transformers. Loose or corroded contacts, load imbalances, poor cable joints or an overloaded transformer generate excess heat, and this is easily identified by a thermal camera, often well before the problem would be picked up by a normal visual inspection or electrical test.
The AC Electrical camera can provide direct temperature measurement of a single point with an accuracy of a fraction of a degree C, so it is more than sensitive enough to identify heat bleed along a cable within a bundle. The ABB team also takes a digital photograph of the same view seen by the thermal camera to enable the problem area to be clearly located and the results of the survey are downloaded to a PC for storage and further analysis.
Because it is a non-contact technique, which can be carried out at some distance from the equipment, thermal imaging is ideal for situations where downtime has to be kept to a minimum. For example, it can be useful to carry out a thermal sweep prior to an annual shutdown to enable the maintenance team to focus on the most likely problem areas, with the additional advantage that the equipment is checked in an on-load condition, when faults are most likely to occur. A thermal sweep can also be carried out as part of a regular preventative maintenance check and the records compared after every visit to indicate any changes in the condition of the electrical equipment.
AC Electrical’s HV maintenance and inspection service is provided by a highly trained and experienced team which is capable of working with equipment from any manufacturer. The main focus is on planned maintenance, but the team is also happy to carry out short-term maintenance projects. With thermal imaging now allied to ultrasound monitoring – carried out as standard on every maintenance exercise – and transformer oil sampling, AC Electrical believes it now offers the uk’s broadest service for private distribution networks.