Knowing the state of the generator that is tasked with providing backup power to your cell tower is critical to the continuity of a carrier’s wireless service during a power outage. But there are also less obvious insights that can be identified by monitoring a generator.
Today, carriers and tower companies need to know what’s going on inside of the generator. They need to understand when it will run out of fuel, the odometer reading, and the status of the battery, Amy Walther, Vice President of Sales and Business Development at Westell, explains to Inside Towers.
“When it comes to maintenance, preventing one truck roll can save the company up to $1,000,” Walther said. An odometer reading is required by some states that limit how long a generator can run due to environmental regulations. Monitoring can also prove that the weekly test of the generator was successfully completed.
Generator Monitoring During Power Outage Events, Disasters
In the event of a mass power outage, real time data on the operation of multiple generators is crucial for an operator to confirm its wireless network is up and running.
Carriers and tower companies need to be aware of fuel levels during long-term events like hurricanes. The runtime calculation, however, may be more complicated than just figuring out the remaining fuel. It depends on the efficiency of the generator and the traffic load on the site.
How Generators are Monitored
With a smart generator, a direct connection to the generator control panel can be made, which allows for more functionality. For example, diesel fuel can be monitored straight out of the generator’s smart controller. If the generator uses propane, however, a separate smart gauge must be installed at the fuel tank.
Monitoring a generator without a smart controller results in a more limited, yet vital, amount of information. By monitoring dry contacts, the carrier can tell if the generator started or failed. It can also monitor fuel with a smart gauge. Additionally, the carrier can remotely start and stop that generator by connecting to the automatic transfer switch.
Monitoring Fuel Levels
With a smart generator, a carrier or tower company can see fuel levels that come straight from the generator control panel, and with a non-intelligent generator they are going to see their fuel levels at the fuel gauge.
“Monitoring fuel, we can show the tank has 78 percent of a tank of fuel, how many gallons are left, and how many minutes of use remain, that’s our intelligence at the edge” Walther said.
Changes in temperature will impact the readings. A positive or negative shift can occur as the fuel expands and contracts, which should be taken into account when the tank is being filled or when the seasons change.
More than Monitoring
Carriers and tower companies need to do more than just monitor their generators, however. To reduce emissions and fuel, they may need to override the generator’s clocks for testing purposes.
“Many of the older transfer switches are not able to run bi-weekly and some companies are saving money by running bi-weekly vs. weekly,” Walther said. “So, now we take over the generator’s clock with our remote devices, and the customer can run the test whenever they want.” Technicians may need to remotely test only on days when air pollution is below a certain level as prescribed by the Clean Air Act; this is possible when using the Westell solution.
Stop Fuel Theft
With real-time generator monitoring, the carrier or tower company can track how many gallons per hour the generator is using. Fuel will drain too quickly when it is being stolen, which will set off an alarm.
Another form of theft can occur when the fuel company doesn’t fill up the tank completely but bills for a full tank of gas. With generator and fuel monitoring, the carrier or tower company is apprised of how many gallons went into the tank and so it can compare it to the fuel bill.
The Importance of Surge Protection
When introducing generator monitoring, the carrier or tower company should consider surge protection. Using an external device that protects against surge is critical for propane-powered generators.
“Surge protection is important but many times this gets overlooked,” Walther said. “If the generator monitor is wired into the propane tank, a surge protector must be installed on that propane tank, because protection against surge is imperative.” The alternative is connecting with Westell’s wireless 900 MHz fuel gauge which eliminates the need for surge protection.
New Technology = More Affordable Monitoring
In January, Westell added the DM Series of DIN-rail mountable modular devices, which provides low-power, low-cost options to monitor remote tower sites. The DMX, a primary unit, and the DME, an expansion unit, are both made of lightweight polycarbonate and are easy to ship, install and manage, according to the company.
The DMX series features a CPU module that includes a high-performance core to store their software locally. This series of remotes has expandable storage via an SD slot and redundant Power over Ethernet (PoE) options, and the flexibility to add modules depending on your need which helps keep the cost down
The Differentiator
The DMX-1600 caters to carriers and tower companies that have Ethernet backhaul from the generators, while the DMX-1648 adds 4G LTE via a field-swappable modular modem and includes dual SIM cards, if they want a backup network.
“The DMX-1648’s modem is field replaceable, which means that the next time you need to upgrade your modem, for instance to 5G, the technician can do this in the field eliminating the need to send in the RTU for an upgraded modem,” Walther said.
The DM series now features redundant, or back feed, power. Should either the DMX or peripheral DME lose power, the back feed power intelligence will kick in pulling PoE power from the unit that does have power.
Conclusion
The reason cell site generators must be monitored can be summed up in two words: service continuity.
Carriers are under pressure to provide coverage 24/7, even under the worst conditions. When commercial power is off, carriers must know that their generators are running and when they will need to be refueled.
The pressure on carriers doesn’t end there, however. They must abide by environmental regulations and be able to prove how long generators have run, which requires monitoring and the capacity to start and stop the units at a moment’s notice.
To learn more, go to https://www.westell.com/markets/intelligent-site-management or contact Westell at https://www.westell.com/contact/sales.
By J. Sharpe Smith, Inside Towers Technology Editor
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