FCC May Revise Rules Concerning Disruption to Comms During Disasters

I agree with this. What I asked about is if you were advocating not starting the generator for some hours after the mains failure. That seemed to be what you were saying in a previous post. If that is what you are saying, then it is wrong. If what you are saying is that the generator needs to be started as soon as possible after a mains failure, then that is correct. So, which is it? Should the generator be started as soon as possible, or should there be a multiple hour wait?

This is what you posted:
"At this point in history, batteries have high enough energy density to be used for that purpose. Something like 24 hours worth of first level battery backup, after which time a generator starts and runs."

 

The generator could be started as planned (or after repaired or replaced) within an expanded time window. I didn't mean by design to prevent operation, and I recognize that it sounded like that. What is needed, and seriously, is more time in the event they don't start or transfer, in order to deal with the failure, yet maintain site operation.

 

All the sites I manage run on -48VDC, floating on battery strings from 125AH to 1105AH. Propane or natural gas (from the Utility) runs the generators, which test weekly and DO transfer on tests. I have had 2 sites in the past 7 days run on generator power due to utility outages. Roughly 150 repeaters. I have never had a transfer switch fail when needed, I have replaced them because they failed during a test. The only failure I ever had that took a site down (from a power failure) was due to the radiator exhaust vent becoming frozen over - while running pushing out hot air - during a "bomb cyclone" blizzard.

The generators start when power is lost. The batteries provide both the bridge between the utility and the generator, and a 6-8 hour window to get on site should the generator not start or transfer. Telemetry lets us know that we have utility power, generator power, and main panel power. And I even have a manual transfer switch and a trailer mounted generator (diesel) that I can park at a site if necessary. A backup to the backup.

Trunked systems aren't as fragile as some of these posts make them out to be.

Huh, first post on here in like a year an a half.

 

You start the generator within minutes of an outage, not hours. Floating batteries are extremely reliable, more so than generators. Generators can run longer, however. You use the generators first, batteries are for when the generator (and utility) have failed. You don't run down the batteries, then goto the generator.

 

I know morse code and I'd still look at you like you were crazy because that's kind of a crazy thing to do.

 

DUH...
In my network the gene4rator turns on as soon as AC fails. Recharging them expensive batteries. You do not discharge your batteries unless absolutely necessary. You see when you discharge any cell the life drops each time.
But hey what do I know?
You know network operators also run simulated emergency test like hams?
I have restored towers and microwave links within 24 hours of losing multiple towers. Large network providers have lots of resources. Like shipping tree cutters, fuel trucks, campers and food for employees and network.
Been there done that for 30 years.

Why should wireless companies report and monitor E911? We do not operate or maintain 911 centers! Your local goverment does!

 

Sounds like you test your machines the "right" way. Large, multi-use facilities often do not, meaning a simulated loss of utility power, so as to check all components. I'm only making a statement based on the Commisison's complaints about loss of power causeing loss of coverage. To me, that spells either 1) no generator, 2) generator failure to start or transfer failure, or 3) battery non existent or not maintained and failed. Lead acid batteries do lose life and must be routinely load/discharge tested to determine remaining capacity.

The philosophy of immediately starting generators is rooted into planning where no battery exists or if one does, it has not been evaluated routinely as it should be. New battery chemistries such as Lithium Ion, along with rugged dependable fuel cells as backup power sources offer opportunities to improve emergency power performance. And, in low temperature environments as well.

Just because "we've always done it that way," is no justification for continuing, where performance sucks, as the Commission said it did post Ida. What are your ideas to improve upon e-power failure affecting telecomm infrastructure?

And I'd like to hear how you resolve loss of trunking controller channel. Last time I looked, that is trunking's Achilles' Heel. "Soft Fail" mode is a complete failure, operationally. First responders can't use a local cell repeater to communicate more than a mile or so. Worthless concept based on cell phones that has been shoved down hapless first responder leaders' throats.

 

This really has nothing to do with the ham radio community, not even mentioned in the report, this is basically a fact-finding inquiry to understand and cover their perspective tails on why emergency communications of the commercial nature failed so terribly.

As an amateur radio operator, it is my priority to take care of my family first, then If ASKED, I will assist the community.

The last thing an emergency manager wants to report Is that volunteers with two way radios saved the day.

 

Welcome Martin; I see you're finally coming around. Where's that data?

 

Not sure where you're getting your information from, thats not how trunked systems work. The work just like ham repeaters do - input and output. We have analog simplex available in EVERY RADIO as well. They are not based on cell phones. For our system, in the event of a loss of the control channel, the site rolls to the secondary control channel. No service impact except loosing a channel. In the even of a loss of the Zone Controller, sites go into site trunking. Site trunking is just like stand alone repeaters; you can still communicate locally, just not across the system. All radios have 8CALL90, 8TAC91, 8TAC92 programmed in, and can talk with dispatch via these analog repeaters placed on high sites if needed. You can steer radios (via code plug programming) to preferred sites should they encounter site trunking. There are lots of things you can do for different failure modes.

Paging and MDTs have moved a lot of the exchange of information off of audio, and units can be notified, go in service, on scene, clear, etc., without ever talking if needed.

Training on how to use it is the issue. Training on what to do/expect in an event that might never happen is where issues come up. Building resiliency (redundant zne controllers for that failure mode) is one way to deal with that. Only once in about 20 years has our system experienced a zone controller failure, due to a corrupt database during an upgrade.

P25 Digital Trunking has given us interoperability capabilities that many places are still dreaming of. The County Sheriff's Office, City PD, Fire, transit buses, every utility truck, and all the regional PD, fire departments, etc, are all on the same system and can - when needed - communicate directly. That goes for our neighboring counties, as well. The entire state is tied together on a system with over 200 sites. A fire truck from 80 miles away can show up and talk to us on our system.

It's not perfect, nothing can be. Properly designed, a system like this can be very reliable.

 

No, it's rooted in the knowledge that when you are running on batteries, you're on your last form of power. Comm managers don't want to be in the position of being on their last resource, especially if another resource is available, but not being used. It would be hard to explain to your superiors why that emergency generator wasn't running when the power went down. "We decided we'd run a while on the batteries, we know they're in good shape", isn't the proper response.

 

One of my site maintenance contractors makes monthly site visits, and throws the main utility disconnect and observes the operation of the site. Did the generator start cleanly, without hesitation? Did the louvers open in the generator room? Transfer take place cleanly? I remotely monitor my Eltek rectifiers over Ethernet, and every battery is measured and evaluated independently - not just the string. I have a LOT of data that gives me a view into the operations readiness of all my sites. Fuel levels, utility voltage, power consumption, HVAC temp outputs - you name it. Accuenergy power monitors log usage, capture transient events; - I can show you the voltage and current waveform plots during a transfer event. Data tells me what's happening.

AGM lead acid batteries are heavy, but much cheaper than Lithium Ion (or similar) batteries. Heavy doesn't matter in this application. I don't doubt they will make inroads as the prices come down, but today I can buy more AH capacity per $ in Pb.

 

Well that is different than the last two glass house data centers I worked in 20-10 years ago. Liebert units with battery backup kicked in, after about 20-40 seconds the generator would start up. This was protection from brownouts, and short interruptions. I was in the glass house when the east coast and Canada went out during the day and saw on the other side of the glass the lights go out in CubeVille. 2003 was it? It happened just as I pulled an Ethernet cable out of a Cisco router and startled me.

EDIT, I later see you explain it similar. I also agree that high tech batteries and fuel cells give more options.

 

Maybe this will help understand the power "choices". In order of availability/reliability:
1. Floating batteries. No switching required, no moving parts, local to the equipment. Proven in CO's for 100+ years. Very short term power, last line of defense.
2. Utility power. Primary source (long term), but generated far away (generally) and failures in the distribution system are usually what brings down the power.
3. Backup generator power. Local, but limited by fuel source and dependant on a lot of moving parts - literally. Most of our sites will run for 3-5 days on the fuel that's available, after that we need to deliver fuel and potentially do some maintenance on the generator. I have had generators run for 10 days with a 2-3 hour service outages while the site ran on batteries. I know of sites that have run for 45 days.

If you deplete your most reliable source BEFORE going to a less reliable - you have no buffer to act should it not work. You hold your batteries in reserve should all else fail. They are your last, most reliable source of power.

How do you make power more reliable? Make sure these systems work. I have a 4th line of defense, a 35kW diesel mounted trailer with a 200A Appleton jack that I can bring out should #2 fail and #3 needs maintenance, fails, runs out of fuel, etc. Propane is stable longer, but diesel is more easlly transported. It can also be staged at a site should we have to take the site's backup generator off line for repairs. I had a water pump fail this week at one of my sites (telemetry showed a "LowWater temp alarm", which is usually a failed block heater but in this case the coolant leaked out - yikes!), and my trailer mounted generator was ready to stand in should the repairs not be quickly completed. Layers of defense...

 

This is what a 22kW DC plant looks like - 11, 2kW rectifiers and 3 strings of 125AH batteries, all -48VDC. There is room for another string for future expansion, if needed. This will run my site's RF equipment for ~8 hours at 100% load, longer under normal system usage.

The site itself is part of a 6 site, 18 channel simulcast cell, and the loss of a single site isn't catastrophic as the system has lots of overlap by design.