Abriox

AT TRANSFORMER RECTIFIERS

NACE guidelines are for monthly checks at TRs. Permanent monitoring can therefore be highly cost-effective, with a rapid payback on the manual cost of gathering data - as well as the associated vehicle/fuel cost and environmental impact from vehicle emissions.

The MERLIN TR Monitor will alarm if power is lost to the TR or if output thresholds (high and low) for voltage or current are exceeded. It should therefore be possible to reduce the frequency of site visits to the minimum required to check that the TR has not been damaged (typically 6- or 12-monthly). This can often be carried out with an annual electrical safety check.

Sites where remote monitoring may be particularly useful include:

• TRs where access is difficult or authorisation is required from a landowner

• TRs sited at busy roadsides or rail crossings where there is a safety hazard

• TRs with a history of power failure (whether due to natural events or equipment faults)

• where a reference cell can be cabled from the pipeline into the TR, so that the ON potential at the drain point can be monitored from the MERLIN TR Monitor.

Useful measurements at Transformer Rectifiers are:

• Voltage output of the TR

• Current output at the TR

• AC supply to the TR

• Pipe-to-soil (ON) potential at the TR or the drain point, which is usually close by

• Instant OFF potential at the TR

In addition, the output of the TR may be switched so that CIPS or DCVG surveys can be carried out along the pipeline.