Powering To A New Level Of Efficiency Causes Electrifying Results
ASCO critical-power management system updates a medical center’s power distribution. It’s the hospital’s way of powering to a new level of efficiency through a better CPMS.
Author:George EvansSep 02, 20244.8K Shares124.8K Views
Mike Wiruth, a master electrician at Bryan Medical Center in Lincoln, Nebraska, realized that the monitoring and control requirements for the facility’s power distribution system had outgrown current capabilities.
Too much data, gathered during monthly tests, had to be entered on spreadsheets and collected from multiple sources. The process took too much time and introduced opportunities for human error.
Wiruth wanted to simplify testing procedures and cut the time required to produce reports. He recognized that standard monitoring-and-control software would no longer support the center’s very decentralized system, which was not paralleled.
He needed a critical-power management system (CPMS).
Powering Bryan Medical Center
The center’s East Campus relies on its emergency system to power nearly all operations spanning its 1,075,000 sq. ft. of floor space.
Facilities include:
- a 382-bed hospital
- Bryan Medical Plaza
- Edward office building
- Faulkner Medical Plaza
- a 700-student college
More than 2,100 employees depend on the center's emergency-power system during power outages.
Wiruth decided the CPMS for the power distribution system, which includes six generators totaling more than 4,000 kilowatts (kW) in rated capacity, required highly automated and flexible monitoring, control, and reporting functionalities.
The system needed to capture data from the utility feeds coming into the center to 37 power transfer switches and leads.
He said:
“„We bring in 12,470 volts from two different feeds, one each from two different utility substations. If one substation goes down, they can throw a vacuum breaker to transfer us to the other substation.- Mike Wiruth
The main switch-room distribution feeds 10 substations located throughout the medical center.
One substation is dedicated to five chillers, and the remaining nine feed all other loads. The six gen-sets are not paralleled.
Wiruth said:
“„We elected not to parallel them because they’re located throughout the campus - from a ninth-floor penthouse to a basement - rather than in one centralized plant.- Mike Wiruth
He added:
“„The gen-sets and transfer switches were added over time as the center needed additional emergency power.- Mike Wiruth
As a result, the system comprises multiple busways.
Wiruth explained:
“„To parallel the gen-sets, we would need to run a lot of common buses, making changes to existing busways costly.- Mike Wiruth
He added:
“„To be honest, we like the multiple busways because we consider them ‘veins’ of power that provide considerable redundancy. If one fails, for whatever reason, it does not affect power throughout the campus.- Mike Wiruth
Redundancy And Timed Sequence
Redundancy is also built in with the sixth gen-set. Should normal sources fail, all six gen-sets start simultaneously.
Five bear the 4,000-kilowatt (kW) load. Two are rated at 620 kW and one each at 750 kW, 800 kW and 1,000 kW. One feeds five transfer switches as the second power source.
The gen-sets branch to different areas of the campus; so, if an event disables part of the power system, the rest of the system continues to thrive with the multiple buses described earlier. A 2,000-kW gen-set assumes the load of any generator that might not start or fail.
Though the gen-sets start at the same time and are online in less than 10 seconds, they accept non-critical loads in a staggered, timed sequence.
Wiruth explained:
“„I considered each generator and each equipment branch-transfer switch. I then prioritized each generator’s loads.- Mike Wiruth
For example, an air handler for surgery comes on before one that supplies office space.
Essentially, life-safety and critical loads come on in 10 seconds or less. Using the power transfer switch controller timer:
- priority-two loads come on in 20 seconds
- priority-three in 30 seconds
- the next in 40 seconds
Wiruth said:
“„That way, we’re not dumping all the equipment loads on the generators at once.- Mike Wiruth
Before the gen-sets accept their loads, a series of uninterruptible power supplies (UPSs) bridges the gap between normal source failure and the time that prioritized loads transfer to gen-sets.
According to Wiruth:
“„UPSs power computers throughout the center, and a 300-kVA UPS powers the data center, which serves not only the Bryan Medical Center campus, but also sister units of Bryan Health on another campus.- Mike Wiruth
The data center manages the following:
- patient information
- billing
- administration
- operations
The UPS input is on one generator and bypass input is on another generator, each with its own transfer switches connected to different distribution panels.
The 37 power-transfer switches - five of them generator to generator - manage which source feeds the variety of loads, ranging from:
- surgery
- intensive care
- emergency lighting
- X-ray and CT equipment . . .
. . . to the data center, chillers, food service, and other loads.
Transfer switches managing the most critical loads always have live power on both sides.
In the event of an internal outage, such as a breaker trip, they immediately switch to the second live source, meaning the center is protecting itself from external and internal outages.
All power-transfer switches used range from 260 to 3,000 amperes (A) and operate in the open-transition mode, meaning they break with one power source before connecting with another.
Because some were more than 20 years old, they were retrofitted with digital controllers and power managers.
The retrofit also included:
- upgrading software
- replacing control panels
- removing existing serial-communication cards
- changing communications medium from twisted-pair RS485 to Ethernet
The six gen-sets were also outfitted with the power managers and Ethernet cards.
This helped ensure that components would support the highly automated CPMS that Wiruth wanted.
Specific Requirements
Wiruth had specific requirements for the new system to conduct system tests and report results.
He needed to be able to conduct a test of the entire decentralized emergency power system from a single computer screen. He also wanted to test a single gen-set with a load bank and get an automated report.
Other capabilities that had to be part of an overall CPMS included:
- the ability to operate the system from as many as 10 client computers
- viewing historical event logs, power readings, and overall system operation
- the ability to change power-transfer switch settings from the software
He also wanted to receive emails automatically on a variety of events and reports.
Ideally, the system also should piggyback on the center’s existing VLAN (virtual local area network) Ethernet network to minimize installation time and avoid having to run a secondary RS485 twisted-pair communications structure.
The ASCO PowerQuest 5750 CPMS from Emerson Network Power (Florham Park, New Jersey) was chosen for the facility. The flexible CPMS connected to the existing VLAN network.
The system’s security uses AES (Advanced Encryption Standard) 128-bit encryption to protect the center’s emergency power system against unauthorized data access and control.
Bryan’s I.T. department connected cable to the closest I.T. closets and provided IP (Internet protocol) addresses assigned to emergency power equipment through facility routers.
Additionally, the CPMS remotely connected to the system to perform software upgrades and diagnostics throughout the start-up process. The system allows viewing the status and test of the emergency power system from a single computer screen.
Wiruth said:
“„Now, we highlight multiple transfer switches on one computer screen and give one command to ‘go.’ Before, we had to go from screen to screen to screen to tell each of the 37 automatic transfer switches to go separately.- Mike Wiruth
He doesn’t want to think about how much time it would take to conduct tests manually at each transfer switch.
He said:
“„It’s invaluable to do from one location, from one screen.- Mike Wiruth
Automatic email alerts and reports provided by the ASCO system have proven to be one of the many benefits of the CPMS because generators and transfer switches are in parts of buildings where no one is around.
Wiruth shared:
“„When a generator starts or load transfers anywhere on campus, I know it. When I was on vacation, my partner did a ‘no-load’ test, and I knew it got done because I got an email telling me it was done.- Mike Wiruth
Wiruth also highly customized the CPMS, explaining:
“„As we gained experience...it occurred to me that it would be helpful to monitor actual load on the generators during tests.- Mike Wiruth
He continued:
“„To see an actual number showing the exact percentage of a gen-set’s nameplate kilowatt rating that is under load, in addition to the slide scale rule that’s part of the 24-inch generator screen display, would tell us at a glance when a test met Joint Commission’s 30%-of-nameplate load requirement for a given amount of time.- Mike Wiruth
Wiruth added:
“„The customized capability also helps me trend gen-set load growth; so; I know how much load I can add to a given gen-set during a facility remodeling or expansion.- Mike Wiruth
Final Thoughts
Other gen-set information monitored includes maximum, minimum, and average volts (V), amperes (A), and hertz (Hz).
Wiruth said:
“„It eliminated the need for a paper spreadsheet, and since it’s now electronic, I can access it remotely off campus from a computer or my phone, so it’s always available. And we continue to fine tune the system.- Mike Wiruth
So, powering to a new level of efficiency has been advantageous to Wiruth as he carries out his job as a master electrician.
George Evans
Author
George Anderson, an exceptional architectural designer, envisions and brings to life structures that transcend the realm of imagination. With an unwavering passion for design and an innate eye for detail, George seamlessly blends form and function, creating immersive spaces that inspire awe.
Driven by a deep appreciation for the interplay of space, light, and materials, George's innovative approach redefines the possibilities of architectural design. His visionary compositions leave an indelible mark, evoking a sense of wonder and transforming the built environment.
George Anderson's transformative designs and unwavering dedication continue to shape the architectural landscape, pushing the boundaries of what is possible and inspiring generations to come.
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