Nace CP 1, Руководство по эксплуатации

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Troubleshooting 9:9
CP 1 – Cathodic Protection Tester Course Manual
©
NACE International, 2000
07/01/04
reaction cannot permeate away from the anode. The gas increases the anode
to earth resistance, thus reducing the rectifier current output.
Drying of Soil
In times of drought or very low soil moisture content, soil resistivity
increases appreciably. This will cause an increase in the groundbed
resistance to earth. Higher voltage settings will be necessary to produce the
desired current.
Before making major changes in the voltage output, however, check the
level of cathodic protection on the structure. In high soil resistivities, less
current is required for protection than in soils of low resistivity. You may
be able to maintain protection, therefore, with less current during dry
periods than otherwise.
Rectifiers
Routine Maintenance
Many problems with rectifiers can be prevented by regular maintenance.
The primary objective of a good rectifier maintenance program is the
prevention of failures and prompt repair when failures do occur. For energy
pipelines, regular monitoring is required by code.
If certain basic observations are undertaken each time a routine rectifier
reading is to be made, many potential failures can be avoided. The
following list of observations can lead to early detection of a potential
problem.
•
Listen for unusual noises.
•
Look for signs of heat (discoloration).
•
Look for vent obstructions.
•
Look for significant output changes.
•
Smell for unusual odors (examples: rotten egg–selenium failure, ozone
–insulation failure, burning–insulation failure).
•
Feel for unusual heat. (Turn off power before touching live
components.)