Substation battery replacement

[cornbread]

I need to replace some batteries in a substation. Looking for some guidance / procedures on how to do this safely on-line. Any help would be greatly appreciated.:?

 

[ActionDave]

I don't know what your situation is. I have done battery installs and swap outs at cell sites.

Two things that helped us a lot was a battery lift which is a two wheel hand truck with a platform that elevates and a homemade handle made from an eight inch long piece of double stitched nylon strap with bolts the same size as the threaded holes in the battery terminals punched through end of the strap.

Hooking them up was just a matter of taking time and being mindful of not letting any of the metal bars slip.

 

[GoldDigger]

I think a large part of the preparation will be finding out where you can walk and what you have to stay away from at the substation. The actual battery location should be relatively safe.
As for equipment, the normal gloves, insulated tools and maybe some rubber sheets to put over battery tops or busbars where you are working.
Find out just what tools are needed for the battery wiring, including torque wrench and specs.

 

[wbdvt]

Typically when I have replaced batteries at a substation a temporary battery bank is brought in and connected so as to maintain the DC System. After that, it is the standard safety procedures for working around batteries, plus other items such as handling the individual battery jars. Depending on the weight a lift may be necessary.
Install would be to follow the manufacturers procedures. Usually they are very good. Pay attention to using insulated tools, no-oxide grease and torque the intercell connectors.

 

[meternerd]

I only know about POCO substations, so my opinion may be extreme, but....why risk an on-line changeout? Too much risk of losing protection or false tripping. Maybe the private sector is different. The best thing to do is take the station off line by switching loads to alternate circuits, open all the DC loads and relax. No stress in an off-line sub. They say they can't take it off line, but it's usually just because it takes time. It can be done....maybe it's just me though. I've tripped more than one sub messing with the DC. Even using a backup bank (if you can create or find one), there's always a time when you are unprotected. Substation faults can be pretty impressive.

 

[big john]

Typically when I have replaced batteries at a substation a temporary battery bank is brought in and connected so as to maintain the DC System. After that, it is the standard safety procedures for working around batteries, plus other items such as handling the individual battery jars. Depending on the weight a lift may be necessary....

Agreed. We've done many.

Pre-charge a temporary battery bank and hook it in parallel with DC bus. Make sure it's sized for the worst-case expected load for the duration of the outage.

I would caution you against ever opening battery circuit and expecting the charger to carry the load, even momentarily. Even if it looks like the charger has the capacity for the load, some chargers are designed to only maintain an output through the battery impedance and will immediately shut down if that circuit opens and you will very likely trip on loss of DC.

After that it's just standard acid and weight precautions when dealing with batteries.

Be wary of initial inrush with old chargers: I have run into the rare analog unit that wasn't smart enough to self-regulate when the brand-new discharged string was put online, and they rapidly went into severe overcurrent.