For most people, the phrase smart grid brings to mind sleek power grid infrastructure or rooms full of engineers in white lab coats monitoring streams of data. Most smart grid installations aren’t quite as sexy as those images, but there’s an even bigger fallacy surrounding the lore of smart grid technology – that it lives exclusively in the realm of large investor owned utilities (IOUs). That’s not true.
In fact, smaller power distribution organizations like co-operatives (co-ops) have just as much to gain by bolstering their efficiencies. Operating over 40 percent of the nation’s power lines, co-ops can effect meaningful change to power distribution in the U.S. by adopting smart grid technology. Rural co-ops can realize large gains in efficiency for relatively small spends on this scalable technology and achieve remarkable returns on investment.
Before diving into why co-ops have so much to gain, it is important to understand precisely what smart grid technology is currently capable of. When a grid is referred to as smart, that indicates it contains these characteristics:
- Intelligence: Smart grids rely on a steady stream of data from remote distribution line sensors and monitors to construct an understanding of what is happening throughout the network. In simplified terms, more data leads to greater intelligence.
- Communication: In order for data to be analyzed and used, it must be relayed to a central control center where it can be aggregated with other data to build true intelligence. This process relies on real-time communication with line sensors and other integrated devices.
- Control: Smart grids don’t just collect and analyze data, they also react to it. When remote sensors detect conditions that require corrective action, equipment such as capacitor banks, switchgear, voltage regulators, and load tap changers can be activated from the control center to respond accordingly, correcting problems and optimizing line conditions.
Once those three core capabilities are in place, smart grids can really spring into action and start delivering value. New devices are continually under development to expand the capabilities of smart grids, but there are a few key functions that utilities are most interested in. These specific functions fall under the encompassing moniker of distribution automation because they can be initiated and adjusted using algorithms without the need for human involvement.
- Advanced metering infrastructure (AMI): Smart meters are the most ubiquitous form of AMI and this is the most customer facing aspect of smart grid technology. AMI allows utilities to remotely meter energy usage without relying on meter reading personnel and service can be remotely activated or deactivated without the need for a site visit.
- Volt/VAR optimization (VVO): Concerned with maximizing power line efficiency and preventing loss, VVO ruses real-time data from power lines to calculate ideal voltage and VAR profiles. With information on load conditions like power factor, active and reactive power, smart grids can adjust how electricity is sent to minimize losses on distribution lines.
- Volt/VAR control (VVC): Somewhat related to VVO, VVC is used to optimize voltage levels on power lines, striking a delicate balance between lowering voltage to minimize waste while producing enough voltage to prevent brownouts. This tightrope walk depends heavily on real-time energy usage information throughout the grid.
- Secondary transformer monitoring: Remote monitors can provide information on secondary distribution transformer load, temperature, and insulation oil health. This information alerts technicians when preventative maintenance is necessary and extends the lives of these costly devices, also nipping issues that could cause outages or expensive repairs in the bud.
- Self-healing: Smart sensors and fault indicators detect when faults have occurred and control centers are able to respond by using reclosers, switchgear, and capacitor banks to route power from alternative energy sources around them until they can be cleared. When automated, this action can occur before customers experience service disruption.
- Theft prevention: An emerging technology that takes advantage of smart grid communication networks is energy theft detection. Using specially designed portable remote monitors, utilities can measure actual energy usage and cross-reference the data with billing records to detect energy theft, even when it occurs directly from distribution lines.
Anatomy of a co-op
Though co-ops distribute electricity in a variety of settings, they are most often associated with rural areas. There are over 863 rural co-ops in the United States, delivering power to just 12 percent of the nation’s population – but because co-ops typically service low density areas, they operate more than 40 percent of the distribution lines that cover almost 75 percent of the country’s land mass.
This combination of extensive line length and low customer density amplifies opportunities for co-ops to benefit from the efficiencies smart grid technology provides. Rural co-ops face a simple math problem: the overhead associated with each mile of distribution line is the same regardless of how many customers it serves. Since fewer customers equates to less revenue, covering the fixed costs associated with electricity distribution can be a challenge for most rural co-ops.
Without economies of scale through more paying customers, rural co-ops have no choice but to bill higher rates to cover infrastructure costs and capital expenditures. On average, rural co-op customers pay 275 percent more than the national average for electricity. As non-profit member owned companies, the billing rates customers pay for energy usage are directly tied to the costs of acquiring and distributing electricity. Subsequently, they are mandated by their members to operate as efficiently as possible to minimize costs.
Controlled by boards of directors, co-ops are almost always more nimble than IOUs because they do not generally have to go through the bureaucracy of obtaining approval from legislative bodies to change rates or make significant investments in infrastructure. This agility along with pressure from members to optimize efficiency to lower prices positions co-ops well to move quickly on new technology and on upgrades that will reduce costs and increase reliability in the future.
Controlling line losses
The distance covered by distribution lines owned by rural co-ops introduces special considerations. Utilities, co-ops, and municipalities alike face energy losses from line inductance; it’s one of the most prominent sources of waste. These losses are typically associated with warm climates because air conditioners rely on induction motors that can lead to large inefficiencies. However, losses from inductance are also influenced by length of line. Rural co-ops that operate long line lengths face this type of inductance on a large scale.
When inductance levels are known, VVO can modify VAR profiles to minimize losses associated with them. Inductance due to line length increases with distance, so the amount of remote sensors required to control this type of loss is much lower than would be required to combat losses resulting from a large number of induction motors running on a relatively short length of line. Rural co-ops can achieve gains in efficiency through small spends by adding line sensing equipment to support capacitor banks that compensate for inductive losses.
Distance complicates keeping the lights on
Inductance isn’t the only special issue that long line distances cause for rural co-ops. Technicians at these co-ops also oversee much larger territories than those at urban Intelligent Operation Centers (IOCs), which can make finding sources of outages and other issues difficult and expensive. Any electricity distributor without line sensing infrastructure relies on customer complaints to become aware of outages; but they don’t know exactly what is causing the outage and where the problem is located. Technicians must be dispatched to find and correct the problem.
This has been a large source of inefficiency even in densely populated areas, but is amplified in rural locations. When customers are spread out, it is more difficult to estimate where a problem is located based on who is affected. Not only do technicians have longer distances to travel in order to start looking for problems due to their large territories, they also have much longer lengths of line to search for outage sources.
Outages in rural environments take longer to locate and fix, costing technician man-hours and keeping customers in the dark for extended periods. Also, rural technicians have to drive further, burning more fuel and increasing the chances that they will work past their scheduled hours and cost even more money for crossing into afterhours pay scales. Imagine the frustration of a rural co-op member who must wait long periods of time to have power restored while paying almost three times the national average for service.
Truly smart grids are able to heal themselves by detecting faults and automatically rerouting power. For rural areas where multiple sources of electricity are not available, rerouting may not be an option. However, line sensors can greatly improve the efficiency and cost of power restoration by immediately alerting control centers of an outage so technicians can be dispatched before affected customers start calling.
The real value, though, comes from fault location isolation and service restoration (FLISR). Fault circuit indicators not only alert control centers that an outage has occurred, they isolate where the fault is. They can attempt to correct the fault automatically by triggering reclosers to activate and clear the line, which restores power about 80 percent of the time. If the reclosers fail to clear the fault or if reclosers are not implemented, FLISR technology can direct technicians to where the fault is located so they don’t have to drive for miles inspecting line.
Industrial loads in the country
Rural co-ops may serve lower density populations, but they also often have different types of corporate customers. Large scale commercial and industrial operations that are served by critical load distribution transformers like manufacturing plants, petrochemical processing facilities, food processing plants, and a wide array of industrial operations are often located in rural areas serviced by co-ops. Heavy load, multi-phase distribution transformers are some of the most expensive and difficult to service devices electricity distributors have, so managing the lifecycle of these capital assets is vital.
Failure of these transformers also has detrimental effects. If such a transformer fails unexpectedly, it could literally mean thousands of people are unable to work and countless dollars are lost until the problem is corrected. Therefore, it is extremely important for co-ops to ensure that these transformers are kept in good working order – but regularly scheduled maintenance can only do so much.
Transformer monitors that are capable of detecting and reporting conditions like load, temperature, and even combustible gas levels are becoming more common and affordable. Monitoring transformers between regularly scheduled maintenance allows co-ops to ensure that this equipment is operating correctly and efficiently. When variables fall out of spec, technicians can respond early, avoiding more costly repairs later and the possibility of unexpected failure. This also keeps critical load transformers operating efficiently and extending their asset lifecycles, which saves members money.
More places for thieves to hide
It is estimated that energy thieves in the United States cost utilities $6 billion every year in lost revenues. As more tamper resistant meters and AMI technology are implemented, energy theft is trending toward sophisticated implementations that tap distribution lines before they are metered. Illegal operations like marijuana grow houses that have the capability to siphon massive amounts of electricity are becoming much craftier and difficult to detect, often going so far as to install their own transformers and underground lines.
Detecting energy theft has largely depended on rather rudimentary techniques like tips, visual inspections, or just plain luck. Professionally installed illegal hook-ups are on the upswing and challenging to detect in any environment, but rural implementations are especially challenging due to high probability of this activity being completed without being noticed by anyone. Once in place, it becomes extremely difficult to find and stop these operations using traditional means.
The best way to detect energy theft is to cross-reference actual energy usage with billed usage, but meters are the only devices most co-ops have to measure real usage. So what can be done when meters are bypassed? Specially designed remote energy monitors are now available that report usage from distribution lines. Many of them are portable, so they only need to be installed until theft is confirmed and stopped. Then, they can then be moved to another location and begin the process again. Using devices like this, rural co-ops can easily detect large amounts of energy theft with only a few monitors.
Increased efficiency passed on to members
Smart grid technology isn’t a magic bullet that instantly replaces legacy infrastructure. It is an encompassing term that includes a variety of devices that are scalable depending on specific situations and needs. Rural co-ops can evaluate their grids and make decisions on what technology makes the most sense for them, increasing efficiency without spending more on equipment than they will gain in reducing losses.
Utilities are under pressure from public utility commissions to increase efficiency, decrease emissions, and curb theft, while co-ops are under direct pressure from members to reduce costs and rates. Doing so does not require enormous budgets or robust engineering payrolls. Wisely implemented smart grid technology will certainly result in an appreciable return on investment and satisfy the member mandate to deliver energy as efficiently and inexpensively as possible.
About the Author
Kevin Mays is product/application engineer at IUS Technologies with over 20 years of engineering design, product development, and technical sales experience. He holds a BSEE from Northeastern University and his circuit design and technical expertise was gained while employed at Motorola, Uniden-America PRC, and Maxim Integrated Products.
