For Electric Utilities
A 21st Century Electric Distribution System
Needs 21st Century Grounding
Electrical energy plays a wholly mission-critical role in contemporary society. This simple truth belies the complexity that underpins generation, transmission, delivery and maintenance of massive national and international electrical grids. In the U.S. alone, over 2000 distribution utilities operating about 7000 generating plants, 450,000 miles of high-voltage transmission lines and 5.5 million miles of local distribution lines, strung on more than 180 million primarily wood, and concrete poles, bring electric power to in excess of 320 million consumers and tens of thousands of businesses. ¹⁺²
At the commercial level, sophisticated electronic devices, from super computers and data centers to climate control systems and transportation traffic management rely on consistently uniform frequency and voltage in electric service. Fluctuations in voltage as spikes and surges, inconsistent current frequency, or even worse as a full interruption of electric service can easily damage microprocessor equipment which is the foundation of so much of the world’s commerce. Additionally, any form of electric current anomaly can result in highly dangerous conditions for users of electric energy.
Residential customers have an equal need for highly consistent, reliable electric power. This condition is amplified by the transition of houses and apartments to highly electronics-driven (if not dependent) structures, from mechanical systems and appliances to communications and entertainment.
Importantly, greater dependence on electricity means we are placing increased demands on electric distribution networks. The addition of weather-dependent "Variable Generation Resources" (wind & solar) onto the supply side complicates network management further.
Taking all of the above into consideration, both the complexity and the necessity of delivering extremely high quality, consistent power becomes apparent.
While most U.S. power companies strive for, and report an uptime of over 99%, various network reliability studies reference a 2012 U.S Government report that reveals a typical resident can expect to lose power about 1.5 times per year with an average duration of 240 minutes.
When interruptions in electric service do occur, networks must have the ability to quickly recover their full distribution capacity. Planning for capacity challenges and rapid recovery from natural disasters is essential. As discussed below, ensuring distribution networks have sufficient resiliency through the use of protective hardware and circuitry is at the core of such planning.
Many times, service outages are caused by either lightning- or load-related surges that temporarily interrupt circuits, or damage distribution equipment. An analysis prepared for the U.S. Department of Energy on Reliability of the U.S. Electricity System reports in addition to system stress from variable generation resources, "... peaking loads (such as air conditioning) and non-resistive loads (such as induction motors, variable frequency drives, fluorescent lighting, and electronic devices) change the demands placed on the power system…. [These] can only be accommodated with new technologies and infrastructure."
Unfortunately, in spite of dramatic improvements in system and grid operating management, our rapidly growing dependence on high-quality electric power is saddled with literally 19th Century technology in one of the most important components of electric energy distribution and safety infrastructure: Electrical grounding, throughout the world, is way behind the times. The vast majority of electrical grounding throughout the world is accomplished through ground rod-based earth terminations. Faraday, Morse, Westinghouse, and Edison used this same concept. For the time, such a design was entirely sufficient. This is no longer true.
Substantial innovation in grounding techniques is now critical. When incorporated as a replacement of or supplement to existing, century-old concepts, better grounding can produce greater system reliability, eliminate equipment damage, and improve operating margins for electric utilities. This, in turn, results in benefits for utility owners and investors, as well as costs to customers.
Toward this goal, by combining various materials into a unique, patented configuration based on sound principles of physics and engineering, GroundLinx Technologies has created the first major “re-thinking” of electrical grounding or electric utilities, and specifically for pole-mounted electric distribution networks in over 40 years. We have adapted our Gradiance™ system to massively improve grounding performance (for resistance, frequency response, and fault duration ability) in a simple, pole base-and-wrap design that installs with no additional labor time, yet can substantially cut fault-related equipment losses. GroundLinx systems are able to “intercept” fault currents nearly regardless of frequency, prior to mechanical protection devices tripping, and hence equipment being damaged, customer service interruptions occurring, or lives being endangered.
In the present operating environment, all of these concerns are absolutely critical.
If it works . . .
The old adage of “If it works, don’t fix it” doesn’t apply when the “it” doesn’t work well enough. And that’s exactly the case with rod-based grounding.
Accepted, traditional grounding for power distribution by electric utilities calls for the use of solid copper and copper-clad steel ground rods, along with “6 AWG” solid copper wire. Typically, at a minimum, one pole in five carrying distribution wires must be grounded. Many utilities, however, more aggressively ground every pole. Further, if a pole supports equipment such as transformers, “cut-outs”, fuses, or capacitor banks, grounding must be accomplished with at least one ground rod, as opposed to a simple coil of wire around the buried base of the pole.
These guidelines have been in place for many years. However, in locations where soil conductivity is poor (effectively an unknown until 30 years ago), rod-based grounding does not perform at all well. More importantly, on circuits prone to surges and steep wave front events (i.e. intense high-frequency currents), simple copper coils and rods are nearly always deficient in mitigation of the excessive, or fault current, particularly in low-conductivity soil. The result is generally severely damaged, or destroyed equipment, and in extreme cases, major losses incurred by customers due to failure of the distribution system to manage / dissipate fault currents. Significantly, the latter situation is becoming increasingly common due to some of the social and network trends mentioned above. Attention to this matter by distribution utilities, from a liability standpoint, would seem prudent. The difficulties being faced by California utility PG&E presently, likely due to arc-flash fault(s), strongly attest to this observation.
This brings the question to mind, why do electric utilities appear to overlook this critical aspect of distribution operations? Two answers come quickly to mind:
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Traditional grounding is seen as the only option available, and
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If another option truly is available, it is seen as cost prohibitive.
The development of the GroundLinx Gradiance™ system makes both of these statements inaccurate.
The Dollars (and Sense) of GroundLinx Grounding Solutions
Truly for generations, simple ground rods have been considered to be sufficient. However, the demands and financial realities facing electric utilities in the 21st Century no longer support this belief.
The GroundLinx Gradiance™ grounding system, has been proven to be dramatically more effective than traditional grounding (including that with soil amendments) in terms of resistance-to-ground, impedance matching, and frequency-range dissipation capability. That means a surge, spike, or lightning strike that commonly damages or destroys an aerial (or ground based) transformer will far more likely be mitigated by a Gradiance™ installation, thus preventing on site, and downstream damage. Granted, Gradiance™ installations are more expensive than ground rods and wire, but recouping of this cost is more than accomplished when the first equipment damage event is prevented. A simple dispatch of a truck and crew to a damage site requiring 4-8 crew-hours, excluding the cost of equipment replacement can, in many markets exceed $1000, fully accounted. Add a transformer or two, and the numbers jump very quickly
Gradiance™ installations ARE demonstrably more effective at damage prevention than traditional grounding. That means lineman crew-hours, and equipment & maintenance budgets can be cut. In high-probability-of-damage regions (much of the US Southeast qualifies for this due to high rates of lightning discharges), and on individual circuits known to have frequent surge and load related troubles, upgrading to more a more capable grounding strategy makes financial sense….in a big way. The surprising and unique resistance reducing characteristics of GroundLinx grounding solutions yield nearly zero-maintenance, highly resilient, cost-effective fault-current mitigation, massively outperforming traditional grounding.
While many electric utilities have scheduled preventative inspection and maintenance programs, performance measurement and overall efficacy of grounding throughout a given distribution network is generally not performed sufficiently. The result far too often is the occurrence of highly preventable loss of equipment and facilities, not to mention customer goodwill. If a thorough inspection program is already in place, addition of grounding efficacy checks, if not already practiced, would be judicious. Additionally, continuing analysis of maintenance costs to identify where a given network is suffering regular losses, is a wise, cost-saving, risk management strategy. Where high resistance grounding is discovered, conversion to the dramatically advanced grounding techniques of GroundLinx Gradiance™ systems will result in substantial financial and operating benefits very quickly.
In the bigger picture, as load stress and power conditioning issues increase on electric generation companies, transmission networks, and power distributors – concurrent with the demands of an electronics-dependent economy and society, taking every step toward improving system reliability and safety is a sound decision. The across-the-board benefits of modernizing from the huge limitations of accepted 19th Century ground rod technology… to the significantly more capable, reliable, and stable grounding offered by GroundLinx Gradiance™ grounding systems – are financially clear.
Notes
¹ “U.S. Electrical Grid Undergoes Massive Transition to Connect to Renewables“. Scientificamerican.com. Nov 21, 2015.
² “Top 9 Things You Didn’t Know About America’s Power Grid“. Energy.gov. Nov 21, 2015.
