Method and apparatus for monitoring electric insulation conditions in energized electric systems
OwnerArkady Aynvarg, Yuliy Budovskyinventors
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Abstract
A method and an apparatus for monitoring conditions of electric insulation in a live or energized electric system. The invention takes into account the fact that, when the insulation resistance of an electric system is measured under real live conditions, the electric insulation works under voltages and current-leakage conditions which different from those measured in so-called “cold” state. The invention is based on two voltage measurements in one of which the operating conditions of the electric insulation are artificially changed for a known value. Insulation parameters are then calculated by a set of formulas using the results of the two measurements.
Claims47
A method for monitoring parameters of electric insulation in an energized electric system comprising at least, a conductive base, a first insulated wire and a second insulated wire with a voltage between them, said first insulated wire having a conducting part and an insulating part which insulates said first insulated wire from said conductive base, said second insulated wire having a conductive part and an insulating part which insulates said second insulated wire from said conductive base, a first detectable potential difference existing between said conductive base and said conductive part of said first insulated wire, and a second detectable potential difference existing between said conductive base and said conductive part of said second insulated wire, said potential differences being caused by current leakages from said conducting parts of said first insulated wire and said second insulated wire to said conductive base through said insulating parts of said first insulated wire and said second insulated wire, said energized electric system having a resulting leakage power and a resulting leakage admittance, said method comprising the steps of:
- measuring by means of a measuring system at least one of said detectable potential differences at a first moment of time for obtaining first results of measurement;
- changing at least one of said detectable potential differences by changing at least one of said parameters of electric insulation by a known value;
- measuring by said measuring system at least one of said detectable potential differences at a second moment of time for obtaining second results of measurement;
- and
- determining said parameters of electric insulation on the basis of said known value and said first and second results of measurement for obtaining current values of said parameters of electric insulation.
An apparatus for monitoring parameters of electric insulation in an energized electric system comprising at least, a conductive base, a first insulated wire and a second insulated wire with a voltage between them, said first insulated wire having a conducting part and an insulating part which insulates said first insulated wire from said conductive base, said second insulated wire having a conductive part and an insulating part which insulates said second insulated wire from said conductive base, a first detectable potential difference existing between said conductive base and said conductive part of said first insulated wire, and a second detectable potential difference existing between said conductive base and said conductive part of said second insulated wire, said potential differences being caused by current leakages from said conducting parts of said first insulated wire and said second insulated wire to said conductive base through said insulating parts of said first insulated wire and said second insulated wire, said energized electric system having a resulting leakage power and a resulting leakage admittance, said energized electric system may be selected from a group comprising an alternating current system and a direct current system, said apparatus comprising:
- means for measuring at least one of said detectable potential differences;
- and
- means for changing at least one of said parameters of electric insulation by a known value.
Dependencies are inferred from the claim text.