PCRX: Overcoming Capacitance Effects on Interrupted Surveys

Confirming effective cathodic protection on a target structure involves verification of accurate measured potentials to compare against industry criteria. This is often performed via an interrupted survey to remove certain errors, yet a capacitive effect present in some situations may influence the readings, leading the operator toward incorrect conclusions. In the webcast, we will address the causes of capacitive effects and relationship to decouplers, using real-world field data to demonstrate how to identify these via the waveforms from interrupted surveys. Key aspects that must be considered prior to a survey will be discussed, including safety. Additionally, Dairyland’s involvement in field research and product development to address these challenges will be covered, along with the various possible solutions including the newest innovative solid-state decoupler from Dairyland: the PCRX.

The presentation will illustrate the benefits of using the PCRX in place of traditional decouplers for applications with problematic instant-OFF responses related to decoupler capacitance. Namely:

· More Accurate Potential Surveys: When properly installed on isolated pipelines, the PCRX can virtually eliminate the measurement error associated with decoupler capacitance.

· Safer Surveys: With the PCRX in place, there is no need to disconnect the decouplers during a survey, ensuring the AC voltage on the pipeline remains at safe levels throughout the survey.

· Faster/Lower Cost Surveys and Troubleshooting: The PCRX eliminates the added time and recurring costs associated with having to disconnect traditional decouplers for the survey.