Stray voltage - a problem that just won't go away

Sunday, February 6, 2011

Oxford County's Allan Innes is convinced that it is still a headache for a number of Ontario farmers and is trying to build a list of those affected Is undocumented stray voltage still an issue on Ontario dairy farms?

by DON STONEMAN

Oxford's Allan Innes thinks so, even though the province brought in new regulations and tougher standards for power distributors nearly two years ago. So the Embro dairy farmer launched a campaign of his own last fall to try to suss out stray voltage across the province, starting in his own Oxford County.

The Oxford County Federation of Agriculture featured stray voltage in the newsletter it publishes in a local regional farm publication in December. But if stray voltage is to be found on local farms, farmers aren't talking about it. Field services representative Janine Lunn says that, three weeks after publication, the newsletter had spawned no responses.

That is in stark contrast to an article in an earlier newsletter about solar power generation in the farm that was distributed the same way. Lunn says she received calls from every county where the publication was distributed, convincing her that it is well-read. "I have not heard directly from anyone" on stray voltage she says.

Lunn, who grew up on a dairy farm, admits stray voltage "is kind of a touchy subject. Not everyone wants to talk about it and not everyone knows who to talk to." There is the issue of being labelled as a poor manager. "People have had that happen and they are afraid," Lunn says. The county federation will continue with its outreach program, she says, stressing that "we need to hear from the individuals."

Stray voltage is more officially known as ground-to-earth voltage. A June 2009 Ontario Energy Board ruling set the maximum neutral-to-ground earth voltage  at no more than half a volt. Previous to that, the Ontario Electrical Safety Code Rule 75-414 established the maximum neutral-to-ground earth voltage as 10 volts. Utilities were required to mitigate voltages above that. Problems with volts below 10 V were the responsibility of the customer.

Innes says he doesn't have stray voltage himself, but it is a problem elsewhere. He says he has the names of 12 producers with stray voltage from a list of 200 farmers he is trying to call. "We are trying to sort out the legitimates."

Some of the affected farms are several counties away. In his view "they are all my neighbours" and deserve help.

"I talked to one producer and he has put in a monitor," Innes says. Voltages as high as 28 volts have been recorded in the middle of the night in the barn. Innes says the present, recently revised standard of half a volt still isn't good enough. "We are not happy with point five. At point five, a cow can still pick it up."

Innes cites several cases of farmers in the county who have either gone out of the business recently because cows were dying or have installed blockers to deal with stray voltage, and it remains unsolved. He believes that blockers deflect stray voltage from one farm and send it to another.

Stray voltage has been a special research interest for Michigan State University professor Truman Surbrook, a master engineer, managing director of the Michigan Agricultural Energy Board and the Electrical Outreach Programs Co-ordinator.

Surbrook helped develop the rules that utilities must follow when dealing with farmers in Michigan, Wisconsin and Idaho. He says there is no new research into stray voltage and research dollars are now being aimed into alternative energy generation.

"There aren't very many (stray voltage cases) any more" in Michigan, says Surbrook, and it's not because utilities bully farmers. "We wouldn't let it happen." On the other hand, there are about 20 cases a year in Michigan of stray voltage linked to installations of new in-ground swimming pools. Stray voltage is a human health issue, Surbrook says.

Swimming pools are now equipped with equi-potential planes, substantial grounding systems, just as new dairy barns are.

There may not be research into stray voltage any more, but there is certainly controversy over how to solve problems such as the current that Wellesley Township dairy farmer Allan Erb says affects his dairy farm. (See "One farmer's battle to get 'ground current' out of his barn," Better Farming, October, 2010.)

Erb says nothing has changed since August. "Really, nobody can help." He says he measures the current on pipes in his barn regularly and there is a correlation between higher current and higher mastitis incidence in his cows.

Waterloo North Hydro serves Erb's farm. Dave Wilkinson, vice-president of operations, says a mailing to known farm customers in its distribution area in July resulted in visits to 20 farms. Wilkinson says two sites produced measurements of more than the one-volt Ontario Energy Board threshold. (The threshold is actually half a volt). Dairyland Filters were installed at both sites. "We are scheduling more testing to go back there and measure the results now that the filters are in place," he said in December.

Erb says the current in his barn increases as new houses are built in the area.

"When you build more houses," explains Surbrook, "what they are probably doing is adding more load to the neutral of the primary conductor, which then creates more voltage draw, which then creates more of an issue coming from the utility side of the system."

But how do you solve that? Surbrook and electrical forensics consultant Donald W. Zipse, based in Wilmington, Del., vehemently disagree.

California doesn't use multi-grounded neutral distribution systems, says Zipse. "They don't ground the neutral at the poles. That's why they have happy cows in California."

He maintains that Wisconsin is not as good a place for cows because of the way its electrical distribution system is set up. Five years ago, a change was determined to be financially unfeasible. The state determined that to change its system and add an additional grounding wire that would eliminate the need to ground at poles would cost US$7,500 a mile in rural Wisconsin.

"There are some really important safety and reliability reasons for having a grounded distribution line," Surbrook says. Lightning strikes are only one concern. Another is that multi-grounded systems shut off when wires are knocked down during a storm.

Surbrook is dismissive of Zipse and other consultants. "Like anybody who makes his money off the public, you've got to spread doom and gloom and say 'I've got the solution'."

Zipse acknowledges that his ideas are controversial. "I usually write on a subject where there is not much knowledge about it and I try to educate my fellow electrical engineers."

He says that, at first, the Institute of Electrical and Electronic Engineers would not publish a paper he wrote about equi-potential planes, those grounding grids that are built into milking parlours in new barns in Ontario, and also into the bottoms of swimming pools in Michigan. Zipse concluded that equi-potential planes don't work.

Brant County producer Chris Vandenberg has found that grounding in a new barn can add to the challenges. Vandenberg milks 70 cows with two Lely robots. He realized there was stray voltage in his new dairy barn when he noticed cows suddenly running to the other end of the barn during 2 a.m. calving checks. He believes that the well-grounded milking parlour was actually attracting ground current from elsewhere.

Vandenberg installed a blocker at the barn and sometimes still finds as much as two volts electricity in the barn, but production stands at an average 34 litres per day 11,500 on a 305-day lactation. BF