Solid-State Decoupler (SSD)
Maintenance & Safety Inspection Guidelines
The Solid-State Decoupler (SSD) is designed as a
maintenance-free protection device for cathodic protection systems. However, to
ensure long-term reliability, system integrity, and personnel safety, strict
safety procedures must be followed before any inspection, testing, or nearby
operation.
Step 1: Mandatory Safety Isolation
Power-Off and Disconnection
All inspection or maintenance work must be carried out with the SSD fully
de-energized. Disconnect all cables connected to the device.
Critical Sequence
Always disconnect the cable from the cathodic protection system (pipeline side)
first. This cable is typically connected to the negative terminal of the SSD.
Residual Energy Discharge
After disconnection, use a grounding jumper with adequate current rating to
momentarily short-circuit the two SSD terminals. This safely discharges
residual energy stored in the internal capacitors.
Personal Protection
Operators must wear appropriate PPE, including insulated gloves, throughout the
procedure.
⚠ Safety Notice
If the SSD is actively mitigating induced AC voltage, direct disconnection
without proper isolation may cause the pipeline to float relative to ground,
leading to a sudden rise in pipe-to-soil voltage and serious electric shock
risk. Always complete isolation and discharge steps first.
Step 2: Functional Status Check
After isolation and discharge, a quick functional
check can be performed:
Normal Condition
Resistance starts near zero and gradually increases as the internal capacitor
charges. Observing this rising trend is sufficient.
Fault Condition
Resistance remains low and stable (typically ~1 Ω). This indicates internal
failure and the SSD must be replaced.
Conclusion
Correct isolation, discharge, and inspection procedures are essential to ensure
SSD performance and operator safety in cathodic protection systems.
KIG Team
2026/01/08
