Saving Energy on Campus with Energy Optimization Technology

The Project Universities have long put forth great effort to improve overall energy efficiency for buildings and facilities on campus. To improve electrical energy efficiency, universities have used more economical lighting systems, high efficiency motors, building management systems, and other measures. However, there is one area of electrical energy conservation that has been almost totally overlooked – the energy savings that can be realized by optimizing campus electric distribution voltages. Like many universities across the country, Murray State University (MSU) consistently looks to improve energy efficiency on campus. MSU’s 236-acre main campus is in Murray, KY, a city of approximately 18,000 residents. Founded in 1922, the university has grown from an enrollment of 202 students to 10,400 today. The University buys all its electrical power from Murray Electric System (MES), a municipally owned Tennessee Valley Authority (TVA) distribution utility. In March 2011, Utilidata deployed its AdaptiVolt™ voltage optimization software on Murray State University’s campus. The patented AdaptiVolt™ software has been installed at major electric utilities and industrial facilities in the U.S. and Canada, providing significant energy savings when implementing conservation voltage reduction.

The MSU Main Substation is supplied by two 69 kV sub-transmission lines from Murray Electric System. Each of the 69 kV lines feed a 3-phase transformer, which are both equipped with ±16 step On-Load Tap Changers (OLTC). Only one transformer is feeding the campus at any time and the other serves as a spare. The loads on these feeders includes induction motors ranging from fractional horsepower to 1500 hp, variable frequency drives, lighting, HVAC, building controls, and other typical university campus facility and residency loads. The AdaptiVolt™ system was installed in a control cabinet in the substation, and a remote access console was installed in the MSU electric shop. Twenty-two power monitors, which were installed as part of a new Energy Management System (EMS), provide information to the EMS and voltages to AdaptiVolt™ via the campus’ Ethernet system. Additionally, two revenue class power monitors were installed at the substation for power and energy measurement and two new digital OLTC controllers with fiber optic communications capability replaced the original electromechanical controllers. The AdaptiVolt™ software is connected to the electric metering system to obtain voltage readings, and then issue control commands to the OLTCs to regulate the voltage in the substation. MSU engineers and local electric utility operators have full visibility and control of the system through an Operator Interface Terminal.

• [Process Optimization - Remote Control]
  Real-time control and visualization
• [Efficiency Improvement - Energy]
  Increased energy efficiency
• [Cost Reduction - Energy]
  Reduced energy costs

• Reduce peak demand by almost 4.4% (kW) and has reduced overall campus electrical energy usage by more than 4.8% (kWh)

• The total estimated annual reduction for the year was 2,186,722 kWh, equivalent to a reduction of 1,508 metric tons of CO2 based on the EPA estimated U. S. average

• The average number of voltage tap operations per day on the OLTCs has been reduced by more than 15%.