Magazine November 2019

Grid Router Paves Way For Smart Power

Grid Router

by Ryan Nix

When it comes to the electrical grid, industrial images of tall, wooden poles trailing wires from gray, metal substations to homes and transformer boxes, of circuit breakers hidden in back closets and the crooning of a Wichita lineman all spring to mind. 

These visions of crude machinery chugging along, virtually unchanged since Arkansas’ first electric cooperatives were established as part of FDR’s New Deal, belie the fact that the digital revolution — which includes renewable energy innovations and the increasing popularity of distributed energy resources — has illustrated the need for huge updates to our power grid. 

Modern problems, modern solutions Modernizing the electric grid creates new challenges for electric cooperatives, particularly those providing power to rural regions. Rural populations are almost universally remote and scattered with miles and miles of farm acreage to cover, resulting in voltage drops and imbalances occurring across long feeder lines. When farmers used simpler electromechanic equipment, this voltage fluctuation wasn’t an issue, but modern agriculture is increasingly reliant on digital equipment, which is more voltage-sensitive and prone to damage or failure when voltage significantly peaks or lags. 

Further complicating the issue are unbalanced loads (electricity consumption) caused by large inductive devices, such as the large electric motors found in agricultural equipment. This often results in a low power factor (PF). PF is the ratio between the power that is actually being used in an electric device versus the apparent power, the product of voltage and current actually being supplied to the device. PF is measured from -1 to 1 with 1 representing perfect power efficiency. PF is a result of AC (alternating current) power. As the name implies, the current goes back and forth while the load’s voltage goes up and down but not simultaneously.

For those reading who are not electricians, imagine pushing a child on a swing. The swing goes back and forth. If you push at the right time, all of your effort goes to pushing the swing. If you push at the wrong time, some of your effort is wasted. Think of voltage as the “push” and current as the “swing”. When these two are in sync with each other, you have a PF of 1. If you push when the swing (current) is far away, all your effort (voltage) is wasted, creating a PF of 0, meaning no work is being done. Many systems have a PF of less than one, indicating some degree of energy inefficiency. Systems with large electric motors are especially prone to creating unbalanced loads, resulting in much lower PF, which causes the electric grid to work harder than necessary to supply the lagging current or voltage. 

The common problems of voltage fluctuation, low power factors and general energy inefficiency place stress on the equipment and wallets of agricultural producers, many of whom already operate on razor-thin margins. Essentially, the problems of a modern electric grid require modern solutions. The ERMCO-GridBridge grid energy router represents one such solution.

The grid energy router (GER) was invented by GridBridge, a North Carolina startup now owned by ERMCO, which is a subsidiary of Arkansas Electric Cooperatives Inc. (AECI). Meant to modernize the electric grid, the GER is the first of a new generation of smart devices that actively stabilize voltage drops and spikes from generating points, as well as providing precision control to the amount of power supplied to electric devices and equipment, ensuring that no electricity is wasted.

Voltage reduction isn’t new; utility companies have utilized voltage reduction at their electric substations as an overall cost-saving method for years. However, the GER is installed directly at the customer’s transformer, allowing precision voltage reduction determined by the installer’s specific needs. After users set the voltage at their exact requirements, the GER then constantly monitors voltage activity, reacting to and compensating for power peaks and lags to ensure a consistent voltage level. This voltage optimization can be completely automatic for farmers who want to “set it and forget it,” or controlled directly by remote engineers through the GER’s communication capabilities.

This both reduces power demands and consumption, as keeping the voltage at the exact level needed prevents load imbalance. This leads to a higher power factor, thus ensuring energy efficiency. The National Rural Electric Cooperative Association (NRECA) took notice of these benefits and ran extensive tests on the GER’s voltage optimization capabilities, installing it on poultry farms in South Carolina. Its study found that, “Using the GER for voltage optimization can lower the peak [voltage] demand by around 10 percent without inconveniencing the customer, so you’re seeing some immediate financial benefit,” according to Brian Sloboda, director of consumer solutions at NRECA.

Other companies offer similar devices to the GER, but Sloboda notes that GridBridge’s invention comes with certain advantages. 

“The two interesting things about GridBridge technology: Number one, it’s attached to or combined with the transformer, so you’re able to have a very surgical deployment. Some of the others are feeder-based, and you have to deploy several in that way,” he says. “The other thing is that they’ve included us and a co-op board of engineers for this product, so they’ve gotten good feedback.”  

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