Background

Delaware Electric Cooperative (DEC) is a member-owned electrical distribution company that provides electric power to over 80,000 customers in two Delaware counties. Although DEC established an Irrigation Grant Program to assist farmers with the cost for installing new electrical irrigation systems, customers in primarily single-phase power areas still needed a cost-effective way to implement the three-phase power required to run irrigation pumps. After learning that an Eaton variable frequency drive (VFD) could be used to convert single-phase power to three-phase power, DEC and Eaton collaborated on a reliable, cost-effective solution. Today the VFD solution is helping farmers irrigate crops, which improves yields per acre by 166 percent, saves 68 percent per hour in operating costs by using electricity versus diesel fuel, and allows for interruptible load during high usage periods.

Irrigation system options

Initially, all the motors in the DEC single-phase rural distribution areas were three-phase and were powered by diesel generators. Diesel generators are an expensive alternative and are only 40 percent efficient. They must be constantly refueled, require ongoing maintenance, are noisy and produce significant emissions. With increasing stringent federal and state mandates to reduce emission levels, the use of diesel generators is becoming less favorable.

In addition to diesel generators, there are several other ways to power irrigation systems. Although rotary phase converters provide three-phase power, they are only 80 percent efficient, expensive, unreliable, and require a great deal of maintenance. Additionally, open delta transformers are not only unreliable, but also cause voltage imbalances. Finally, stringing new three-phase lines is too expensive since installing those lines cost $60,000 per mile.

VFD: efficiency, reliability, simplicity

As DEC and Eaton explored alternatives, they determined that using a VFD would provide significant cost saving as well as environmental and production benefits. The new DEC solution

supplies farmers with 480 volts, which eliminates the need for farmers to install a transformer for 480 volts. The electricity goes from the 480 volt transformer directly in the meter pan with single-phase 480 volts to the disconnect switch into the VFD. The VFD, which is 97 percent efficient, creates the three–phase power; therefore, it is an electric phase converter versus a mechanical phase converter. The power moves from the VFD and to a filter that eliminates any harmonic distortion or voltage spikes. (See http://youtu.be/a4WuO6RN53M for a demonstration of the solution.)

Since the VFD acts as a soft start, no additional soft start is needed. It is also programmed to take only 30 seconds to reach full speed (60 hertz). Designed to last 10 years, the VFD simplifies troubleshooting by providing on screen reports detailing fault conditions so corrective action can be taken quickly.

Electrical irrigation advantages and paybacks

DEC’s CEO Bill Andrew reports, “The customer savings can be enormous. One farmer said that switching from diesel fuel to the AGSVX drive panel saved him $2,800 in 500 hours of operation.”

The DEC Irrigation Grant program substantially reduces the investment cost. In addition, the

Three-Phase Power Solution for Irrigation Systems Saves 68% in Operating Costs with the Eaton AGSVX9000Location:

Greenwood, DE

Problem:Agricultural customers in primarily single-phase power areas need a cost-effective, reliable solution for delivering three-phase power to their irrigation systems

Solution:Switch from powering motors with diesel generators to an Eaton AGSVX driven electric irrigation system powered by single-phase power

Results:Enables agricultural customers to implement a cost-saving, reliable, environmentally friendly irrigation system that improves yield per acre by 166 percent, saves 68 percent per hour in operating costs by using electricity versus diesel fuel, and allows for interruptible load during high usage periods.

Contact Information

Readers who may have similar application challenges and would like to discuss this success are invited to call 877-ETN-CARE or John Russler at 920-262-6060.

Success Story: Delaware Electric Cooperative

Markets ServedAgriculture

“Today the VFD solution is helping farmers irrigate crops, which improves yields per acre by 166 percent, saves 68 percent per hour in operating costs by using electricity versus diesel fuel, and will enable DEC to continually increase its business”

Eaton CorporationElectrical Sector1111 Superior AvenueCleveland, OH 44114 USAEaton.com

© 2013 Eaton CorporationAll Rights ReservedPrinted in USAPublication No. CS040002EN / MZ757January 2013

help of the State of Delaware, State Department of Natural Resources and Environmental Control and Energy Efficiency Investment Fund has help expand the DEC Irrigation Grant Program to include funding for the VFDs. Through the program, DEC will pay up to $15,000 of the cost of a VFD for installations above a 40 hp motor and $7,500 for installation less than 40 hp. This enables the investment to be paid back in about 500 hours

Impact on DEC’s business

Andrew explains, “The VFD solution is changing our business because of the load we are generating. Since the power is interruptible, we have the ability to turn it off when we have peaks, which reduces our costs tremendously.

“This solution is also helping us meet state requirements of having 15 percent of our service interruptible and reduce energy demand by 15 percent by 2015. We are also required to purchase or produce 25 percent of our power from renewable resources by 2025. Today, our total interruptible load derived from the new irrigation program is nine megawatts.

“Our members recognize the benefits of the VFD solution. Since we began offering it in 2011, we have received more than 200 applications for the irrigation system. Since there are approximately 1,000 farmers in our area, we can certainly see the growth potential as others adopt this solution.”

National Rural Electric Cooperative Association Senior Program Manager Brian Sloboda notes, “Anytime you can come up with a new way to save farmers money it’s a great solution. There are huge environmental benefits when changing from diesel to electricity. The VFD solution is enabling DEC to add additional resources to its demand response program and that will help DEC in the long term. It is giving DEC the ability to monetize the demand response more effectively, grow its load, save its members money, and add flexibility to its demand response account.”

Product Information

The Eaton AGSVX drive panel provides reliable three-phase power to irrigation systems including center pivot, drip irrigation and water flooding systems. Using proven VFD technology, the AGSVX drive panel converts readily available single-phase electrical power into three-phase electrical power eliminating the inefficiencies, costs, and ground water contamination associated with other three-phase power sources. The panel is also designed with a weather-tight, NEMA 3R enclosure that provides adequate protection in outdoor environments keeping your three-phase power in operation.

For more information visit: www.eaton.com/drives.

Eaton is a registered trademark of Eaton Corporation.

All other trademarks are property of their respective owners.

The Eaton and DEC team installing the AGSVX9000 drive panel.

Eaton AGSVX9000 drive panel.