Emergency shutdown of a SOFC plant

This near miss occurred at a CHP plant operation with a SOFC. During the heating phase, the SOFC stopped due to the opening of the mainpower switch.
This was due to a contact problem inside the SOFC module, but the reason was not clear at first. Many equipment had to be double checked to avoid problem to other components.
Because the SOFC module was at high temperature and a bad smell was coming from the module (probably because of an electrical wire touching some metallic parts), it was decided to go into a safety mode shutdown.
The gas was stopped by the main gas valve, while heating circuit was kept working to cool down the unit. A portable gas sensor was used by plant workers to check possible gas leakages, but nothing was detected. The SOFC went into shutdown mode (flushed with N2) and cooled down slowly.
Manufacturer's personnel performed a maintenance onsite to repair the problem and increased the distance between the wire and the metallic part.

sensor

No damages in any component, nor of the SOFC module nor of the BoP.

Safety procedures were correctly implemented.
The following two lessons learnt are reported for the plan operator:
(1) Importance of having safety procedures already planned and implemented at the plant site .
(2) Cooperation with the manufacturer team remotely connected to detect the problem and organize an effective and quick maintenance visit.

The following lesson learnt are reported for the plant manufacturer:
(3) to have a check of the design of the Balance of Plant around the stack modules.