Battery replacement in a substation
Battery replacement in a substation
(OP)
A few years back we changed out our old wet cells batteries for the new Gel cells. Making a long story short we need to replace the Gel cells. I’m looking for guidance / procedures on how to safely change these one-line. Any help would be greatly appreciated.






RE: Battery replacement in a substation
If the last time you did a 'hot swap,' what's different this time?
I'm trying to understand the question...
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Battery replacement in a substation
RE: Battery replacement in a substation
The general practice for this type of outage in my utility is to bring in a temporary battery bank to provide the necessary degree of uninterruptibility. The Ampere-hour rating of the temporary bank is some fraction of the normal bank's rating, as determined by the Engineering Department taking into consideration the amount of load to be carried and the criticality of that location to the grid. The prime concern is of course that the temp bank last long enough to ride through contingencies until such time as maintenance crews arrive to take appropriate remedial actions.
Using a special portable DC switching tool, the temp bank is paralleled with the existing one, then the bank to be replaced is removed from service, with the process reversed once replacement has been completed.
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Battery replacement in a substation
RE: Battery replacement in a substation
RE: Battery replacement in a substation
This is a true statement, however to stress the importance of this, I will share a horror story.
A few years ago, a plant was changing out a bad cell in a string. Rather than using a temporary battery in parallel with the old one, a decision was made to turn off the DC feed to the batteries and run off the charger (without knowing the details of the charger). Battery chargers can be ordered with the proper filtering to accommodate such situations, but in this case there was not such an option on the charger (sometimes called a battery eliminator, or a filter, etc).
When the batteries were removed( via battery breaker), 8 relays immediately went up in smoke and the plant tripped. Over $250k of product was lost. This battery charger did not have the proper filtering (that the batteries provide when connected). 5 of the relays were static devices and not readily available. The 3 SEL 500 series relays were common enough that power supplies were able to be swapped out from other, similar units.
To be clear on the procedure (and a simple automotive battery will do for a single cell change out, jumper cables (or other suitable) are placed in parallel with the battery to be replaced. After it is established that all connections are secure, the bad battery can be removed / replaced. Un install in reverse order.
RE: Battery replacement in a substation
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]