You need to determine what the caquse for the arcing is.
Could the composition of the flue gas have changed to make it a high resisitivity ash? Increasing Mg and Ca will cause arcing. Na and K will reduce arcing.
Increase in flue gas temperature will cause more arcing by changing the ash resisitivity. The increased velocity will also reduce the retention time and allow more dust to escape.
Are the controls tunned correctly?
Due you have internal mechanical probelms like wire to plate spacing? High ash hoppers? Dirty insulators tracking the electricty?
There are a lot of reasons for arcing, shutting it down my not get what you need.
Another item could be the rappers. If they have failed or are weak/bound up, then the ash is not being shed off of the curtains. That will also lead to arcing.
You could run V/I curves and see if the resistivity or cleanleness has changed. Providing you have some histic V/I curves to compair when the precip was operating well.
Everything JEB66 has said is valid. The key is to determine what has changed OR over what timeframe has the unit performance degraded. Precipitators are very sensitive to volume. Refinery precipitators generally collect a higly resistive dust. This demands that the unit remain as clean as possible. Insure all rappers are operational (and working). Then do VI curves. From this you can determine the internal condition of the precipitator.
