D.C. 911 calls delayed, police radio hampered by power outage

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ThePhotoGuy

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Wait times for 911 calls spiked and police radios went quiet for several minutes on Tuesday afternoon due to a power outage at the city’s Unified Communications Center.

D.C. 911 calls delayed, police radio hampered by power outage - The Washington Post


In fact, the city’s chief technology officer at the time, Suzanne J. Peck, said, “Our communications will never go down” because of the extensive back-up protection.
 

mmckenna

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It would be interesting to see if the transfer switch was the issue. Backup generators are nice, but the common point of failure sits at the transfer switch. Having that fail mid transfer would create such an issue.

Often, it's easy to get complacent with fairly solid utility power and a good back up generator. The common feeling is "we have a backup, we are invincible". Issue is, generators can fail to start, generators can fail, transfer switches can fail. You can add large UPS systems to the mix, but there is still single point failures.
Alternate sites are a good choice, but the transition times can be long. Should be interesting to see what the failure was, or what the blame it on.

We had a back up generator test go sideways once. The controller for the generator tanked and it hit our 220v gear with somewhere around 750v. Smoked a lot of power supplies and took us a while to recover.
 

m-gerty

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Got called to our county hospital several years ago, generator didn't start during a short power outage. Maintenance man said it cranked over but wouldn't start. Dipping tank proved it was out of fuel (diesel), maintenance man said he never had to put fuel in it before, couldn't understand how it could be empty....Yeah, they're out there!!
 

mmckenna

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We've done some dual fuel systems. Being in earthquake country makes using natural gas a risk, but we use it as primary. Most sites have the natural gas feed, then a back up of Diesel or LPG.

Issue with many of these systems is they get installed when the building is constructed, then promptly forgotten about.
 

m-gerty

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This was a old hospital, now gone. It had an underground fuel tank, everything around here that I've seen is natural gas now.
 

jim202

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This was a old hospital, now gone. It had an underground fuel tank, everything around here that I've seen is natural gas now.

Natural gas is great as long as the compressor stations along the transmission pipe lines have power. When the power goes out, the compressors stop and your natural gas stops flowing. This was the cause of very wide spread natural gas outages during and right after hurricane Katrina. Large areas along the Gulf Coast lost natural gas. Results were many hospitals lost their natural gas feed and this caused their generators to go down.

This loss of natural gas is why I am not a big supporter of natural gas emergency power generators. The next bug in the wood pile is the ability to fill propane or LG tanks when the power is out. Other than special tank trucks with pump and a long hose, I don't know of any way to transfer propane from a large tank to the tanks on the ground at your generator. So check with your supplier and make sure they can fill their transport truck if the power is out. Then you only have to worry about trees across the road and flooding.

How many locations do you know of that run their emergency generator for a test, but never pick up the load they are there to support? In my travels around the country, I frequently ask about the backup generator at the dispatch centers. The main question I always ask is if the load is picked up by the transfer switch. If they do that, the following question is how long the test runs. The reason for the second question is to make sure the engine runs long enough to bring the crankcase oil up to operating temperature. If the temperature doesn't get high enough, the moisture that normally collects in the crankcase will not be evaporated from the oil. Left in this condition, the oil can turn to a foamy brownish goop. This goop lacks lubrication and can cause major damage if the engine runs with it for very long.

Another reason for picking up the load on the generator is to exercise the auto transfer switch. These switches, as has already been mentioned, can fail to move from normal power to the emergency mode. Many times they are rusted in the normal position from lack of use. You can beat on them with a sledge hammer when they get like than and you will never move them.

Bottom line here is to run the generator each week for about 20 to 30 minutes and pick up the emergency load on the generator. This tests the entire backup power system. It makes sure the generator will even start. It makes sure that you can pick up the emergency power bus load. It makes sure that the UPS power packages will function on generator power. Plus it lets the facility manager sleep at night during any storm that may roll through.
 

kayn1n32008

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Natural gas is great as long as the compressor stations along the transmission pipe lines have power. When the power goes out, the compressors stop and your natural gas stops flowing.

Well easy way to fix that... Run the compressors off... natural gas... Rather than electricity. Almost all the booster compressors I see in the 'patch are natural gas powered...


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mmckenna

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Yep. We used to take the feed in from the utility and compress it again into liquid form and store it on site. Did that for many years as a way to keep our large co-gen engine running. Worked just fine until the cost of electricity got so high that running the compressors was cost prohibitive.

Haven't seen an LPG delivery truck around here that didn't have a pump on it. Pump runs off the engine PTO, so no electricity needed. Most of our critical sites are Diesel anyway. In reality, if things really get that bad, we likely have bigger issues to worry about.

There will always be weak points, single points of failure, and other issues. There isn't enough money in the world to solve all of them. It's all a gamble, no matter what anyone says.
 

mikewazowski

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We use diesel for most of our standby gensets although I do have one site with natural gas. I've got a small cache of fuel and a 12v pump I can run from my truck or the genset battery should the need to refuel a unit arise. Typically we'll get 4-5 days from a unit before needing to be refuelled.

All units are tested monthly by somebody onsite who can verify proper startup and transfer.

This doesn't eiminate all failures but it does catch quite a few before we're having to deal with them in an outage.
 

JamesO

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Used to work at a place we had a 200kVA generator that had problems from time to time starting.

Turned out to be the utility powered engine water heater failing. The issue is these heaters last about 18 months, when they fail, there is not a warning. Generator would go into over crank when the temps were cold and then the air door would drop and choke off the generator.

We used to have to manually lift the air door on the intake to get the unit started. We ended up putting a line Voltage thermostat in to turn the engine water heater off after the temps got to about 70F, this allowed the water heater to last a bit longer, maybe 24-36 months. We still had to watch the heater and replace it on a PM basis.

The other problem I ran into with a larger residential generator unit was in the cold temps the oil pressure switch would hang. Then the generator would start and shut down due to no oil pressure or at least it thought there was no oil pressure. I went round and round with this and finally just had the $15 oil pressure switch replaced because it only hung or stuck in 40F or below temps.

Part of the problem is Electricians are not Diesel Engine mechanics and few generator service folks have really good Diesel engine mechanics.

I have a natural gas back up generator for my house. Change the battery every 3 years need it or not and manually exercise it every few weeks as in the above case of the oil pressure switch problem, the generator was locked out and then it did not exercise and the home owner was totally unaware that the generator was locked out due to an oil pressure fault.

I ran for 4 hours last week on my generator due to a storm causing a large scale outage in the area.

Wifey was PISSED when I purchased the generator, we talked about it and she said we did not need it. I bought it anyway as I got a KILLER deal on it. Sat behind the house not connected for about 6 months. We had a bad storm that knocked out power for over 60 hours. About 12 hours into the outage, I started getting things connected and brought it online. Since the installation and the 40 hours we had power in the heat of the summer with the main AC unit running on the system, she counts to 20 every time the power goes out and does not complain.

Although it costs to run the generator, turns out it is cheaper than hotel bills and lost food. Not to count the overall inconvenience.

I have over 165 hours on the generator in the past 4 years, so the wife is now sold on having a generator and forgave me for not listening to her!
 
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