The University's Aging Electrical Infrastructure and Its Future
January 23, 2017
Senior Electrical Engineer
University of Texas Health Science Center at San Antonio
| "If Alexander Graham Bell returned to Earth today, the progress in telecommunications over the last 125 years would be mystifying. If Thomas Edison came back today, not only would he recognize our electricity system, he could probably fix it.” | |
| Melissa Lott Engineer Scientific American |
|
Over the past several years, the University of Texas Health at San Antonio has experienced multiple unplanned electrical power outages at its Long Campus. In 2014, the University experienced two large power outages, grabbing the attention of the University of Texas Board of Regents.
| “Power outages have become acute with two major power outages in 2014…and have adversely impacted ongoing research activities” [1]. | |
| Mike O'Donnell Associate Vice Chancellor University of Texas System |
|
History
In this context, “major power outages” means complete power loss to the University. In all cases, the utility providers’ infrastructure was not the cause for the power failure. Rather, after numerous reviews of power load data, electrical current flows and grounding effects, it was determined that the outages were caused by faulty and failing University distribution infrastructure. There are several circumstances that led up to these unplanned outages.
 |
| FM and CPSE replaced transformers in late 2013 |
First and most importantly is the overall age of the University’s electric gear. The existing electrical infrastructure is between 50-60 years old because it’s a combination of then-new 1963 electric gear and used electric gear given to the University by San Antonio’s power company (CPS Energy formerly known as City Public Service Board).
Being that the University’s normal operations are of a 24/7 nature, research, student activities, faculty activities and animal studies span any given day and time. As such, and as in other similar facilities, the electrical equipment has never rested since powering down for a day or weekend is rarely an option because of the internal and external consequences. This would be similar to powering down a large piece of 1960, “high-tech” equipment, and hoping it reboots properly; it would be risky, especially when there are not spare parts available or no complete set of back-up equipment to support a failure. In addition to the electric gear being past its end-of-life, the arteries or the 13.2kV conductors connecting buildings to the main switching station have also surpassed their life expectancy of 30-40 years.
Root Cause of Outages
Similar to a neuron which has a protective insulation layer (myelin), conductors throughout campus do as well. Over time, the insulation degrades and can cause shorts (current flows to ground or to other phases). These shorts are what may trip a breaker, small or large, causing failure in an office, lab, a building or the entire University creating a temporary black out. Likewise, the main pump of the University which pushes electricity throughout the Long Campus is experiencing several complications. The first is a build-up of plaque (similar to atherosclerosis), which does not allow for the current to flow properly. The plaque in the medium voltage (600 volts to 69,000 volts) domain can be seen as ozone residue. Corona is the first stage of a larger problem and if allowed to persist that eventually becomes severe as it transitions into the tracking of electric current then finally electric arcing which can lead to component failures.
This University is not alone in addressing electrical failures and aging infrastructure. In Canada, for example, St. Paul’s Hospital is planning on spending $17 million to replace aging electrical infrastructure in order to provide stability and consistent care for patients. The St. Paul’s expenditure is in response to the facility suffering several power outages [2]. In another example, in early April 2015, Washington D.C. suffered a similar power outage, like those experienced on this campus, due in large part to failing electrical infrastructure [3]. Ironically, the electrical outage in Washington D.C. came just weeks before the U.S. Department of Energy was expected to release recommendations for modernizing the country’s electrical infrastructure.
Unplanned power outages across our medical facilities in the past several years have created anxiety among our research and teaching communities since unexpected power outages can mean years of lost research, lost funding or lost patient data. This University, like many other facilities, has surpassed the design life expectancy of its electrical distribution equipment; see Figure 1. The University is now embarking on the replacement of several large pieces of the 13.2kV equipment and conductors. The most critical component being the “heart”, the University’s 13.2kV switching station, acts as the pump for our electrical system, thereby allowing 13,200 volts to be circulated to all our vital “organs” – the buildings and equipment within each of them.
Project Design and Implementation
13.2kV Switchgear (the heart):
The design was completed in mid-2016. The equipment is currently being manufactured in Houston, Texas, by Powell Industries. This new gear will be in an environment controlled room, it will have networking capabilities so that Facilities Management (FM) can monitor power quality and breaker states. It will be installed in mid-2018. (University Cost: $7M)
13.2kV/4160V Transformers:
In 2015, FM completed the design and manufacture of two large transformers. With the help of GE Energy these were delivered to the University for the installation in 2015 and early 2016. These two pieces of equipment are critical to the Medical School Building (only) since 4160V is the primary voltage (input voltage) to that building. (University Cost: $300K)
34.5kV/13.2kV Switchgear, Automatic Transfer Switch (ATO) and Transformers:
Beginning in late 2013, CPS Energy (CPSE) and the University via FM worked on replacing ALL of the CPSE equipment. To date, all 34.5kV/13.2kV transformers (2013) have been replaced, a new ATO (2013) has been installed, two new SF6 type switchgears (2016) have been installed and new controls (2016) have been installed. (CPSE Cost: ~$2M)
The replacement of medium voltage equipment not only gives the University extra life to the electric grid, it also allows for a higher level of redundancy and provides a greater level of safety to personnel. Moreover, recent data suggests that our power factor has improved from .78 (2013) to .93 (2016) yielding savings in our monthly utility costs.
Additional updates on this project will follow as we make progress in 2017 and 2018.
References
[1] UT System Board of Regents’ Meeting November 2014. Discussion Regarding Agenda Item #6 To Fund Large Electrical System Improvements and Board of Regents Approval.
http://videoportal.utsystem.edu/Mediasite/Play/a315f86fc4da42e4a2991e879deb801c1d
Hour 2, minute 42 and second 41.
[Accessed on December 5, 2016].
[2] We're on life support. The Province. May 2012.
http://www.theprovince.com/life+support+says+charge+Paul/6674415/story.html
[Accessed on January 23, 2017].
[3] Washington blackout highlighted aging electrical grid. Valerie Volcovici. Reuters. April 9, 2015.
http://www.reuters.com/article/2015/04/09/us-usa-grid-blackout-idUSKBN0N02HB20150409
[Accessed on December 5, 2016].