11 December, 2006

More SCADA Expansion - UPS's - Caution

"Increase in oil and gas and power and process control vertical markets is likely to drive the industrial uninterruptible power supply (UPS) market of North America. The growth of this market mainly depends on the technology associated with the equipment and the demand from its end-user markets. "With UPS technology being saturated, the focus is purely on the growth of its industrial applications and the end user vertical market," according to the analyst of the study. "As the trend of oil and gas market in addition to power and process control market increases, the future of industrial UPS market looks bright and promising." "

I think it is great that people are paying attention to ensuring the reliability of their SCADA equipment. While I was at the oil company I saw at least one major (very major) incident related at least in part (there are always several failure that lead to major incidents) to a lack of proper power provisioning.

One Quick caution here.

Pay attention to the security and management issues related to UPS's when installing them. They are often managed by SNMP or other trivially manipulated protocols and some of the more advanced ones can serve as entry points. Linux is often the underlying OS and while this isn't a problem in itself, it does mean that periodic attention to patching and version maintenance should be maintained.

Finally keep in mind that this is another avenue for attack/failure if it is on an essential system.

UPS's for MES and Historians is a good way to ensure you maintain the ability to monitor operations when there is a failure in what is normally a non vital portion of the power system. The fact that these systems are often on the normal power grid is often overlooked. For PLC's and RTU's obviously a well engineered power structure is more important.

Another item to add to the periodic maintenance list - verify power supply fail over mechanism and settings thereof.

Update:

Good Comment by Jake. Jake you should drop a line to DCSSEC at Gmail.com
It would be nice to strike up an out of band conversation.

1 comment:

Jake Brodsky said...

When it comes to UPS gear, I think simple dumb and stupid is appropriate here. We don't need embedded computers to tell us the battery is losing charge. What we need is a dry contact. We don't need to know specifics of precisely how many volts or amps the damned thing is putting out. We merely need an alarm if something's wrong.

Why? Because if anything is going wrong with the UPS, somebody has to go out there anyway and deal with it.

There is a certain assumption among some industries that more information must be better. However, we don't have time to process that much data. We only need the thing to work long enough to get a backup generator on line or to shut down properly.

That's why I like 24 and 48 volt battery systems. There is nothing to break. The battery floats on charge and if power fails, the gear keeps talking until the battery dies.

And in fact, that's what we use in many places. Most of the gear we use doesn't need to run on line power anyway. We can't maintain a 500 HP motor through a power outage, and even if we could there really isn't much to be gained by trying to keep it online.

Thus we backup the telemtry gear just long enough to report that there is a power outage. And as for database servers, our UPS holds us long enough to get the generator started. That's all.

However the biggest limit of all are the batteries. As you pointed out someone needs to keep track of them and maintain them. At some point you'll end up spending more time taking care of batteries than you would had you simply let the power failure happen. I think that's where things are right now.

Remember, this is only a forecast. Forecasters are often wrong. I think this one is...