Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Substation Batteries

Substation Batteries

Substation Batteries

     The utility company I work for has several old lead-calcium substation batteries that are badly in need of replacement.  I am doing some research to determine if there is another kind of battery that will provide a longer life and less maintenance.  The manufacturer claimed that these batteries would last 10 years, but it was only three or four years before we started having problems.  I have chosen to stick with wet-cell batteries for now, since using dry cells would require a change in our standards and practices.
     One type of battery I am looking into is lead-selenium.  Anyone familiar with this type of battery and its pros/cons?  I have been told that there may be some environmental concerns.  Also, any other type of wet cell (and manufacturer) that has proven to function well in your substation applications?  

RE: Substation Batteries

Lead-selinium batteries have been around for a long time and are just a variant of lead-acid batteries.  I'm not aware of any issues that would be different in their application.  Just as nasty as lead-calcium.  I suspect any edition of the Electrical Engineer's Handbook will have more information.  

Ni-Cad batteries are widely used in place of lead-acid batteries, although you will pay a premium.  Lifetime can exceed lead-acid.  Check Alcad website for more information.  These still require periodic inspection and electrolyte level maintenance, although filling is seldom needed.

RE: Substation Batteries


No offense is meant, but flooded lead-acid cells have fairly predictable life, provided they are properly specified, in the correct environment and routinely maintained.  Without same, replacement battery sets will likely not do any better.  Given the disastrous consequences of shortened battery life in breaker-tripping applications, you may want to stick to standard, well understood systems, and be certain of competent maintenance and monitoring.  For ANSI regions, IEEE battery standards might be carefully reviewed and evaluated.  

RE: Substation Batteries

Suggestion: Assuming that there is an existing dc power distribution system including switchboards, motor loads, valves, etc., the battery internal resistance (generally impedance) has to be kept in mind. Certain batteries have a high internal resistance, which would cause very large voltage dips or sags depending on nature of the load. Therefore, it may be a good idea to keep the battery the same or very similar, perhaps to search for a better quality battery manufacturer, if the existing power distribution system is to be properly utilized without requiring costly modifications. It is not unusual to have a short circuit current of the stationary lead-acid battery supply exceeding 20000ADC.

RE: Substation Batteries

If your flooded cell lead acid batteries died after 3 or 4 years, it is likely they were some how mis-treated or cycled too much. I would expect 10 to 15 years. Flooded cell is far better than VRLA for reliability and ability to withstand abuse.

Flooded-cell NiCd batteries are considered by some to be more reliable, longer lived and lower in maintenance than lead-acid. NiCd is commonly used for swgr. There are disposal issues at end of life because cadmium is considered a hazardous waste.

RE: Substation Batteries

The lead-calcium batteries I am referring to are Liberty 1000 Series Lead Calcium batteries.  We have installed them in several different locations, not just one, and in every location they have been installed in, they give us trouble.  We own many substations with lead-acid batteries that are not Liberty's, and those batteries do just fine, lasting us at least 10 years and sometimes even 20.  That's why I believe it is a manufacturer problem, not environmental.
I appreciate your helpful posts so far.  Anyone else had trouble with Liberty 1000's?

RE: Substation Batteries

 ‘Liberty 1000’ appears to be a valve-regalated {sealed} sort.  In general, VRLA sets do not have the track record of the more traditional clear-jar flooded-cell variety.

RE: Substation Batteries

Are there different operating conditions or environment required for flooded cells vs. VRLA's? (e.g. ventilation, temperature, moisture)

RE: Substation Batteries

VRLA's are pretty much fit-and-forget batteries.

Plante cells need a fair amount of TLC to keep them in good condition: electrolyte level checks, electrolyte density checks, makeup fluids as required.

In theory VRLA's don't give off hydrogen during charging. If they are charged too rapidly, they vent hydrogen to the atmosphere. Plante cells evolve hydrogen routinely. I would treat both types as needing ventilation.

Plante cells are available in big sizes - 2V 2000AH being the biggest I've encountered, although I bet submarines use even bigger cells. VRLA's don't come this big.

RE: Substation Batteries

I do not agree with ScottyUK's description of "fit and forget". This is a misconception with VRLA's, you might not have to add water but but do have a lot of maintenance. IEEE 1188 provides all the recommended maintenance activities for VRLA's, not much different then IEEE 450 and in some cases more stringent (capacity test every year vs avery 5 years for lead-acid vented). If you have other vented cells that work why don't you install those in your application?

RE: Substation Batteries

The cells we have are not vented.  They are VRLA's.  They are also generally confined in spaces without much ventilation.

RE: Substation Batteries

VRLA batteries have a bit of a tarnished reputation due to failure rates.  Conventional wisdom is that traditional flooded cells are more reliable and have a longer life.  

You might want to discuss necessary ventilation with battery suppliers.  There is a lot of misinformation regarding ventilation requirements for lead-acid batteries.  Some ventilation is required, but the necessary rate is not really terribly high.  In many cases, we were able to achieve it through normal natural air flow without the need for forced ventilation.  Most problems are created when batteries are jammed into a small "battery room".  The smaller the space, the more ventilation required.

Ni-Cads might be another alternative.  I don't believe they produce as much H2 as lead-acid batteries.  

RE: Substation Batteries

I didn't go through all the replies and therefore may repeat what some of the other members might already have said. The utility I worked for, some years back, had Lead Acid Batteries at one of the power plants which failed within the defect liability period (their plates started expanding and buckling etc). The supplier had to re supply batteries with Ca and they worked fine.
I would suggest to take up the matter with the supplier to see if the batteries are being operated according to their specs. If not they should suggest corrections. If there is nothing wrong with the operating conditions then the root cause of the early failure must be investigated.

I would recommend to check the internal resistance of the batteries and try to follow its trend right after commissioning.
Hope this helps

RE: Substation Batteries

I agree with dpc and nukeman.  I've heard VRLA referred to as "maintenance-proof" instead of "maintenance-free".  They require as much or more maintenance, but you can't get to the electrolyte to check it.  

RE: Substation Batteries

Nukeman and others,

'Fit and forget' was a poor choice of words on my part. What I was intended and failed to get across is that the routine checks on electrolyte level and SG, monthly at our plant, are not possible with VRLA's. IMHO, we spend a lot more time looking after our plante cells than our VRLA's, but in light of your comments I will check with the manufacturer to verify that we are not under-maintaining our VRLA batteries.

Annual discharge testing I totally agree with; our plante cells are getting old now, and the testing frequency has been increased. VRLA's are tested annually as you suggest.

I shall be more careful with my choice of phrase in future.

RE: Substation Batteries

Thanks for all the info.  I will check with the manufacturers regarding ventilation considerations for flooded cell batteries and see if it is possible for us to switch over to those from our VRLA's.  If you have anything else to add, don't hesitate to post, I am learning a lot here!

RE: Substation Batteries

Suggestion: A computer simulation or model of the new battery dc power distribution is prudent to have to avoid any inappropriate procurement of hardware.

RE: Substation Batteries

When purchasing any battery pay attention to the warranty. If its a 10 year warranty with a pro rate after four years guess when you will start having failures.   There are about 60 UPS in the network I work on, we have a lot  Liberty Batteries out there and they are a good battery.  After the four year mark there will be failures of VRLA batteries and between the 5 and 7 mark we change them out. Wet cells seem to be superior the VRLA for life expectancy. How did you treated the batteries i.e. charge rate, temperature etc. There is no 10 year string of VRLA batteries out there that requires no maintenance or cell replacement.

RE: Substation Batteries

My experience closely matches easnj's.

RE: Substation Batteries

Do any of you use or believe in on-line monitoring of substation batteries? I have heard many pros and cons but feel that it is worth the cost to know that all cells are in good condition when an outage occurs.

RE: Substation Batteries

Our experience is the sealed type lead acid batteries typically failed in 3-5 years. The traditional cell with see-though casing seems to be good for up towards 15 years.

For the past 7 years or so we have used a gas re-combination filter ( Hoppecke Aquagen) on these vented cells and this has so far give zero top-up requirement and negligible corrosion around the connectors.

I know of Ni-Cad and Plante cells that I installed over 25 years ago still working as day one but obviously much more expensive.

RE: Substation Batteries

I have seen banks with big bucks install fixed IMP battery monitoring at a high cost on their ups battery system. As I have 60 sites with > 5000 cells the cost prevents us from doing it. However if you have the money to monitor it do it. Being proactive rather than reactive in battery maintenance prevents the outage.

RE: Substation Batteries

Most manufactureres have a range of product line in VRLA batteries. Liberty 1000 is one of the higher quality "10 year" VRLA in my mind. The longer life "20 year" VRLA usually use "AGM" for absorbed glass mesh electrlyte. C&D's Liberty 2000 series is an AGM type and warrantied for 20 years, and I would expect 7 to 10 years before seeing significant numbers of cell failures with that type. A good point for comparison between manufacturers is thickness of the positive plates, or more simply you can compare weight per amp-hour at the same rate (makers of less expensive batteries will argue that this is not valid).

RE: Substation Batteries

Suggestion: It is good to see a battery short circuit transient to get some idea about the battery internal resistance varying in very short time, e.g. millisecond range, to be able to design proper bracing in dc switchboards, and DC switches short circuit current ratings. Many DC disconnects are limited to about 20000ADC short circuit current level. The battery short circuit current transient may easily exceed 20000ADC level.

RE: Substation Batteries

Our Liberty 1000's are most commonly used in small substations that are primarily distribution substations.  These small subs usually have a 10' x 12' panelhouse that contains all the relays and communication equipment, as well as a small office space.  This is where our VRLA's reside.  Obviously, we have to be careful about what we put in there as far as emissions are concerned.  The panelhouses have heating / AC and the batteries are meticulously maintained...you would think the Liberty 1000's would last forever in those conditions, but we have started seeing problems after 4 or 5 years of service.  
The vast majority of the batteries are LS 12-100's which are rated at an 8-hr capacity of 100 AH to 10.5 volts.  Anything similar out there electrically that isn't a VRLA, will last longer, and won't cause ventilation concerns?

RE: Substation Batteries

Don't the 'flame arresters' commonly fitted on flooded jars have any effect on battery location?

RE: Substation Batteries

Suggestion: Often, the battery rooms are furnished with two fans to provide a sufficient redundancy in the rooms ventilation.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close