Stray voltage

Stray voltage

"Stray voltage" is a term commonly used throughout the electric utility industry to describe when infrastructure devices, such as lamp posts, manholes, gratings and junction boxes become unintentionally charged with electricity. The cause of this unintended electric leakage is due to a variety of conditions including cracked insulation, frost heaving, expansion and contraction of wiring, physical damage to the lines and so on. In major metropolitan areas, such as New York City, "stray voltage issues" have become a major concern. In 2005 a woman named Jodie S. Lane was killed in New York City after she was electrocuted after stepping on an electrified manhole cover. [ [http://www.nytimes.com/2006/03/04/nyregion/04voltage.html?ex=1299128400&en=f53afd789fa5445f&ei=5090&partner=rssuserland&emc=rss Con Ed Finds 1,214 Stray Voltage Sites in One Year - New York Times ] ] As a result, Con Edison, the electric provider for much of the north eastern part of the United States, has been testing real time, on-site, stray voltage warning concept, that was patented by the Electrified Cover Safeguard. Nevertheless, each year there are a number of stray voltage injuries to people and to pets.

The term "stray voltage" is also used, primarily in rural areas, to describe the gradient of electrical potential with respect to soil surface location associated with single-wire earth return electricity distribution systems used in some rural locations, particularly in the USA. Campaigners claim this can lead to animals receiving a mild shock from grounded objects, similar to that produced by an electric fence. The term is also applied to a disparate range of electrical and magnetic phenomena more accurately known as EMF (Electric and Magnetic Fields). The physiological effects of these phenomena are entirely different however.

Some claim that stray voltage can have other, more harmful effects on animal health and productivity, and certain American dairy farmers have attempted to claim compensation for damage to yields or stock allegedly caused by it.

Douglas J. Reinemann, Ph.D., Professor of Biological Systems Engineering at University of Wisconsin-Madison, reported in 2003 [http://64.233.167.104/search?q=cache:_Ax072Tt9AoJ:www.uwex.edu/uwmril/pdf/StrayVoltage/03_What_do_we_know_about_Stray_Voltage.pdf+stray+voltage&hl=en&ct=clnk&cd=4&gl=au&client=firefox-a] that an expert study conducted by the State of Minnesota found an overwhelming majority of diary farmers did not regard 'stray voltage' as a danger to their animals. Several field studies have found that the electrical and magnetic fields commonly found on dairy farms are well below the strength required to produce any biological effects. Even when a low level electric current was directly applied to cows, theoretically producing small internal electric fields, no ill effects were discerned.

The report to the State of Minnesota which Dr. Reinemann quoted produced 3 main findings:

* "We have not found credible scientific evidence to verify the specific claim that currents in the earth or associated electrical parameters such as voltages, magnetic fields and electric fields, are causes of poor health and milk production in dairy herds."

* "At the present time, there is no basis for altering the PUC-approved standards by which electric utilities distribute power onto or in the vicinity of individual dairy farms."

* "There are many well-documented non-electrical factors that are known and accepted by the scientific community, and by most farmers as well, to cause dairy cow health and production problems. Among the most noteworthy factors are poor nutrition, poor cow comfort and hygiene, and low or no use of vaccinations and related preventive veterinary practices. These factors should always be addressed by those who want to improve performance of dairy herds."

tray voltage in Wisconsin

In 2003, the Wisconsin Supreme Court upheld a judgement of $1.2 million against the Wisconsin electrical utility WEPCO in "Hoffman"v. "Wisconsin Electric Power Company". The Hoffman family, dairy farmers near New London, had sued WEPCO after several years of declining production. WEPCO had measured stray voltage on the farm below one milliampere, the "level of concern" set by the Wisconsin Public Service Commission, but the court ruled on procedural grounds that the utility could be found negligent under common law even though they met the state standard. The Hoffmans had presented, the court said, a viable alternative theory that stray voltage had caused them economic harm. [cite news|url=http://www.boardmanlawfirm.com/muni_newsletter/muniAug03.pdf
title=Wisconsin Supreme Court Upholds $1.2 Million Stray Voltage Judgment
date=August 2003
publisher=Boardman Municipal Law Newsletter
accessdate=2007-05-30
]

Subsequently, a bill was introduced in the Wisconsin legislature to create an "electricity user's bill of rights", setting a deadline for utilities to eliminate stray voltage and a 30-day window for responding to reports. [cite news
url=http://www.madison.com/wisconsinstatejournal/local/54950.php
title=Lawmaker to tackle stray voltage
author= Tom Sheehan
date=August 17 2003
publisher=Wisconsin State Journal
accessdate=2007-05-30
]

tray voltage in New York City

Consolidated Edison has had frequent incidents of stray voltage. [http://www.thevillager.com/villager_145/isitashockdoubts.html] including the death of Jodie S. Lane in 2004, while walking her dog in [http://www.nytimes.com/2006/03/04/nyregion/04voltage.html?ex=1299128400&en=f53afd789fa5445f&ei=5090&partner=rssuserland&emc=rss Manhattan] . A recent patented invention described on ABC-TV called the Electrified Cover Safeguard may minimize stray voltage accidents since it provides for real time on site warning for street lights, manholes and utility boxes.

References

External links

* [http://www.uwex.edu/uwmril/stray_voltage/svmain.htm University of Wisconsin-Madison Report on Stray Voltage]
* [http://www.manholesafety.com/ 'Electrified Cover Safeguard' website]
* [http://www.strayvoltage.org/ 'Stray voltage' website] from the "LaCrosse Tribune", including their award-winning coverage
* [http://www.mrec.org/pubs/svd.pdf Self-Help Guide: Stray Voltage Detection] , Wisconsin Farm Electric Council (2/1997), well-written, for farmer-consumers, at
** [http://www.mrec.org/sv-info.html Midwest Rural Energy Council] Stray Voltage portal
* [http://www.wisconsinpublicservice.com/farm/stray.aspx Wisconsin Public Service Stray Voltage site]
* [http://psc.wi.gov/utilityinfo/electric/strayvoltage.htm Public Service Commission of Wisconsin Stray Voltage documents] (technical)
* [http://www.pge.com/docs/pdfs/biz/power_quality/stray_volt.pdf Pacific Gas and Electric Power Quality Bulletin No. 2, "Stray Voltage"] (10/2004)
* [http://courant-vagabond.ovh.org - First conference about "Stray currents in our environment" - November 29th 2007 Ester Technopole Limoges, France]


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Voltage multiplier — Villard cascade voltage multiplier. A voltage multiplier is an electrical circuit that converts AC electrical power from a lower voltage to a higher DC voltage, typically by means of a network of capacitors and diodes. Voltage multipliers can be… …   Wikipedia

  • Voltage doubler — A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input. The simplest of… …   Wikipedia

  • Phantom voltage — (sometimes referred to as ghost voltage ) is voltage that appears in an electrical conductor such as a wire, even though the wire is disconnected from an electrical circuit. The term is often used by electricians, and might be seen, eg, when… …   Wikipedia

  • Manhole — For other uses, see Manhole (disambiguation). PMG manhole in a city street, Perth, Western Australia …   Wikipedia

  • Street light — A street light, lamppost, street lamp, light standard or lamp standard, is a raised source of light on the edge of a road, turned on or lit at a certain time every night. Modern lamps may also have light sensitive photocells to turn them on at… …   Wikipedia

  • Consolidated Edison — Company S P 500 Component Type Public utility Industry Energy industry …   Wikipedia

  • Courant vagabond — Un courant vagabond (ou courant parasite) est un courant électrique de faible valeur qui circule de façon non maitrisée dans les milieux et matériaux conducteurs (terre, tuyaux en métal, acier du béton armé des bâtiments, etc.) autres que les… …   Wikipédia en Français

  • Electric power distribution — …   Wikipedia

  • Single-wire earth return — (SWER) or single wire ground return is a single wire transmission line for supplying single phase electrical power from an electrical grid to remote areas at low cost. It is principally used for rural electrification, but also finds use for… …   Wikipedia

  • loading (ordnance) — An operation that installs airborne weapons and stores on or in an aircraft and may include fuzing of bombs and stray voltage checks. See also loading; ordnance …   Military dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”