ground current information

> Below is an article containing information about how much current
> is
> returning to the substations via the ground. I see that it is not
> possible to
> highlight or bold particular statements, but they are in there.
> The Wisconsin PSC has changed their ruling on how much voltage is
> allowed on the ground three times so far. Every time the amount
> exceeds their
> present ruling, they just change the rule. The political clout of
> the electric
> utilities is like that of the pharmeceutical and tobacco industries.
> As the amount of high frequency pollution in the loads increases,
> the
> amount of current that returns to the substations via the ground
> increases
> directly, due to the skin effect.
> Shivani
> -----------------
>
> April 23, 2000
> New state rule won't cover earth currents
> By CHRIS HARDIE Local news editor
>
> A revised state rule that regulates such utility issues as billing,
> meter
> reading and telephone customer response time does not regulate the
> amount of
> electrical current that returns through the earth.
>
> An early version of Wisconsin Public Service Commission Chapter 113
> contained
> a pro posed voltage level, but it was dropped from the version that
> has just
> passed legislative review.
>
> The issue of how much electricity is flowing into the ground from
> power lines
> and its effect on cows is at the center of the controversy over stray
> voltage, the term used to describe earth currents that have an adverse
> effect on
> cows. It is the focus of the Michigan attorney general's office
> complaint against
> Consumers Energy Co.
>
> "It's our view that the utilities have no right to put electricity in
> the
> ground by any means," said Peter Lark, assistant in charge of special
> litigation
> for the Michigan attorney general's office. "There should be no
> electricity
> going into the ground."
>
> The grounded power line system -- which features a grounded neutral
> wire that
> returns current to the substation -- is used all over the country.
> Electricity flows through the system from the substation and returns
> on the neutral line
> and in the ground to complete the circuit. Grounding, the process of
> running
> a wire from the neutral to a metal rod driven in the ground, is done
> for
> safety purposes.
>
> No one disputes that electricity flows through the ground, but the
> controversy is over what level is harmful. And there are no
> regulations in Wisconsin or
> apparently in any other state that establishes a voltage level for
> primary
> neutral-to-earth voltage.
>
> The early version of Chapter 113, which defines power quality terms
> and sets
> utility service standards, set a limit of 3 volts neutral-to-earth
> voltage.
> Mark Cook, manager of the Public Service Com mission Rural Electric
> Power
> Services Program, said the limit was dropped because it was considered
> a double
> standard.
>
> Cook said the PSC's current standard that defines stray voltage -- at
> least
> 0.5 volts of 60-hertz current at animal contact -- adequately covers
> neutral-to-earth measurements.
>
> "We know that one-third of the voltage (in neutral-to-earth voltage)
> will
> show up in cow contact," Cook said. "If we have 0.5 or 1 volt on cow
> contact,
> that's 1.5 to 3 volts at those levels. The average neutral-to-earth
> voltage in
> Wisconsin is about 1.4 volts at the farm."
>
> Cook said there would be difficulties regulating the standard and
> coming up
> with a test protocol. He said some utilities have their own
> neutral-to-earth
> voltage guidelines.
>
> Cook said while there is no PSC rule on how much current should return
> on the
> neutral line compared to the ground, he said the guideline is 66
> percent.
> "The range is actually 30 to 90 percent," he said. "When you have a
> current ratio
> in that range it's unlikely to have a cow contact range above a level
> of
> concern."
>
> But according to the Jackson Electric Cooperative, a power line that
> served
> the Gary Stetzer dairy farm in rural Black River Falls and was
> replaced because
> of stray voltage problems on the Stetzer farm, was returning 70
> percent of
> the current. The new power line, which Stetzer and the cooperative say
> took care
> of the stray voltage problems, returned 85 percent of the current.
>
> A 1995 survey by the Minnesota Public Utilities Commission of 48
> utilities
> found that 59 percent of the current returns through the earth. The
> Michigan
> attorney general says as much as 75 percent of Consumers Energy
> returns through
> the earth.
>
> "The reality is with a multigrounded system, part of the current
> associated
> with customer load flows through the earth," Cook said.
>
> Duane Dahlberg, a retired physicist who is now a consultant for The
> Electromagnetics Research Foundation in Moorhead, Minn., and has
> studied ground
> currents and stray voltage since 1983, said the conductivity of the
> earth determines
> how electrical current returns to the substation. Electricity follows
> the path
> of least resistance, so if the earth is a better conductor than the
> neutral
> wire, the current will flow into the earth.
>
> "There has been no program for determining the magnitudes of these
> currents,
> nor any effort placed on mapping the paths of these currents in the
> earth,"
> Dahlberg said. "The apparent belief is that once the currents enter
> the earth,
> they are 'out of sight, out of mind,' and consequently, little thought
> has been
> given to possible effects.
>
> "It is almost unbelievable that electric current from the distribution
> system
> is free to literally travel through every animate and inanimate object
> that
> is contact with the earth."
>
> Utility officials have told the Tribune that Dahlberg is not a credible
> source, citing an Iowa Supreme Court stray voltage case where the
> court ruled that
> his testimony was not credible.
>
> But according to the Michigan attorney general's complaint, the flow of
> ground currents from Consumers electric system causes economic losses
> and harm to
> dairy and livestock animals.
>
> Charlie MacInnis, director of news and information for Consumers, said
> the
> utility's ground currents do not cause farmers harm.
>
> "There are small amounts of ground current everywhere we go, but in
> the case
> of our system the ground current is principally flowing on the wires
> and the
> small amount in the ground is going from one of our grounds to another
> one,"
> MacInnis said. "It's highly unlikely that any electricity from our
> system has
> any ability to get to the farm."
>
>
>
>
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