The operation of transformer rectifiers (electrical units that place a voltage onto the pipeline to counteract the electrolytic corrosion reaction) is critical to cathodic protection. The voltage must be applied consistently and at the correct level:
Pipeline operators are recommended to check the correct functioning of their rectifiers at monthly intervals.
Manually collecting, monitoring and analysing rectifier measurements is labour-intensive, carries high health and safety risks and is costly. And (very importantly) they can only be reactive – problems can lie undetected for long periods, during which the pipeline is insufficiently protected. By contrast, MERLIN Rectifier and Solar Station Monitors provide an immediate status of the rectifier.
Rectifier measurements are taken automatically by a MERLIN Transformer Rectifier Monitor installed at the rectifier. This checks that the electrical supply is still present, monitors the voltage and current output and (optionally) can take ON and OFF potential measurements at the rectifier drain point.
MERLIN Rectifier and Solar Station Monitors also offer the facility to synchronize remotely with other rectifiers on a pipeline for CIPS (Close Interval Potential Surveys) or DCVG (Direct Current Voltage Gradient) surveys. Excel models can additionally control a solid state relay to provide a signal for tracing the pipeline route.