By Rudolf Carolsfield
The University of British Columbia (UBC) conducts a myriad of operations involving daily classes, research, housing, athletic facilities, and conferences. There are over 35,000 students, 14,000 employees, and 10,000 on-campus residents. All these areas depend on a reliable source of power.
But uninterrupted electricity is a complex proposition. UBC spends $8.6 million per year on power, making it BC Hydro's largest non-industrial customer. UBC Utilities, a division of UBC, is responsible for maintaining the electricity, heat, water, gas, and sanitary services for the entire campus. With 45 employees, UBC Utilities is equivalent in size to many of British Columbia's larger utility and municipal operations.
Two years ago, UBC Utilities realized that they needed an automated power monitoring system to manage campus-wide energy use, improve problem response, and increase reliability.
Seeking Solutions
One illustration of UBC's critical energy requirements is the TRIUMF physics lab, which runs sensitive equipment 24 hours a day, every day of the year. TRIUMF houses the world's largest cyclotron for generating subatomic particles and a proton treatment facility for eye tumors. Scientists also perform research on brain monitoring, detection of plastic explosives, and super-fast microchips.
If any experiment is interrupted by a power disturbance, researchers can lose months of painstaking work, and repeated experiments are costly.
"Our most common power disturbances," explains Utilities Electrical Engineering Assistant, Russell Dobie, "are line-to-ground faults, or short circuits, caused by trees falling onto power lines. The faults produce voltage or current sags with durations of 2 or 3 cycles." These sags can damage or shut down equipment, including motors, and reduce their lifespans. The associated computer crashes lead to lost or corrupted data.
"Ground faults also induce faults on adjacent feeders," explains Dobie, "causing tripping of the 12.5 kV distribution feeders in underground ducts and manhole systems."
Dobie and his co-workers wanted to improve their responsiveness to these problems by more accurately pinpointing the origins of the faults. This required comprehensive waveform analysis to reveal which feeder tripped first. They also wanted to design the distribution system to avoid repeat occurrences and operate more efficiently. For this, they needed access to historical records documenting the causes, duration, and frequency of outages originating both inside UBC's jurisdiction and outside by BC Hydro.
Selecting a Power Monitoring System
To satisfy those needs, the utilities group evaluated several vendors' SCADA (Supervisory Control and Data Acquisition) systems in terms of cost, features, and functionality. They were specifically looking for sophisticated power quality analysis and alarm capabilities.
UBC Utilities chose a monitoring system from Victoria, BC-based Power Measurement Ltd. (PML), primarily due to its high resolution and sampling rate for waveform recording. Plus, it modernized their alarm scheme to a more complete set of conditions, and provided the revenue accuracy required to expand metering into individual buildings.
Installation
Karim Hirji, Manager, Electrical Utilities, observes, "Initially, we installed 3720 ACMs and 3800 RTUs, and now we're introducing the next generation of PML's 7700 IONs, 7300 IONs, and 7330 ION meters. We currently have around 50 meters, and are installing another 25 per year for the next five years in different campus buildings."
Meters have been placed in the main substation on incoming 69 kV transmission lines, on the two main transformers, and on twelve 12.5 kV distribution feeders. The meters monitor consumption, demand, power quality, billing, and equipment status. Further metering in the smaller unit substations at each campus building is planned.
In order to manage the operation of the networked meters, PML's PEGASYS software assesses the overall picture and recommends a new course of action. The software provides uninterrupted processing of alarm and control signals, as well as secure access to power analysis tools from every workstation. At the main substation, a PEGASYS server and the meters are connected through RS-232 and RS-485 links. From there, the server communicates across campus to three workstations at the UBC Utilities office via Ethernet 10BaseT and ADSL modem links.
Improved Responsiveness and Design
The new power quality analysis tools have helped UBC Utilities identify the sources and most appropriate corrective actions for numerous power disturbances, saving the university from possibly damaging consequences.
Dobie has configured alarms for incidents like over- and under-voltages, transformer temperatures and pressures, cooling fan overloads, and water sump-pumps in manholes. The meters are also set up for shadow protection on relays.
If an alarm occurs, the engineers and electricians instantly see it at their desktops, or receive notice of it via pager. They can then make decisions on how to fix the problem in just a few minutes.
With extensive energy profiling and historic records, the electrical utilities group has been able to design a more robust, efficient distribution system.
"We can view voltage and current waveforms, study voltage sags and harmonic distortion, capture transients, and plot data on CBEMA curves," says Dobie. Multi-cycle waveform recording is triggered by combinations of setpoints.
Minimum and maximum values are stored to trend system capacities. Real, reactive, and apparent power is monitored, along with per-feeder and campus-wide power factors. The meters also provide load verification during feeder transfers and switching.
Teamwork with BC Hydro
"UBC is the first site in British Columbia where there is a common link between the power provider's information system and the customer's," Dobie remarks. UBC and BC Hydro jointly purchased two 7700 ION revenue meters for revenue-accurate billing and system analysis on the two 69 kV lines feeding the main substation.
Now, UBC and BC Hydro perform bill verification and power quality analysis with the same data. As a result, UBC was able to save over $70,000 from an outage-related billing error.
Further Applications
In the near future, UBC Utilities and another division, Plant Operations, will collaborate on cost allocation and load shedding as part of their cost control initiatives. Using shared data, Plant Operations will determine which loads may be cycled on and off, and what boundaries can be established for allocating energy costs.
"First, we're going to expand the system to a second 69 kV substation in the university's south campus area," notes Hirji. "Four 7700 IONs will be remotely connected to the main substation via an Ethernet 10BaseT connection and ADSL modem.
"Another potential project is the replacement of our current revenue meters in each campus building with 7300 ION or 7330 ION meters. In 5 years, we'll have approximately 250 metering points."
By taking advantage of the automation, information sharing, and quick integration of their power monitoring system, UBC Utilities expects to see further successes in their energy management program.
Rudolf Carolsfield is an applications engineer with Power Measurement Ltd. ET