High voltage insulation testing system
First Claim
1. A high voltage testing system for testing the dielectric strength of electric insulation characterized by a capacitive reactance load by generating a rated KVA power in the form of a rated voltage and a rated current across the load, comprising:
- a power source for supplying a KVA power less than said rated KVA power;
a transformer having a low voltage primary winding and a high voltage secondary winding, said secondary winding rated for a voltage less than said rated voltage and a current equal to the rated current of said reactance load;
at least one high voltage inductor having a substantially constant inductance value connected in series between said reactance load and said secondary winding, said inductor rated to accept the rated current and rated voltage of said reactance load; and
said inductor and said reactance load forming a tuned resonant circuit, and said power source having a continuously variable frequency tunable to the resonant frequency of said tuned resonant circuit;
wherein the resonant circuit excited by said power source produces high reactive power at the rated KVA necessary to test said insulation, with said power source providing only the active power consumed by said resonant circuit;
wherein said inductor comprises a serial connection of at least two high-voltage chokes with substantially constant inductance values, at least one of said chokes designed in the form of a bar-core choke.
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Accused Products
Abstract
The high voltage testing system contains a series resonant circuit connected to a voltage source with a continuously variable frequency, whereby the insulation, connected in series with the inductor, which is being tested, either exclusively or at least partly, forms a part of the capacitance. The inductance may consist of several high voltage inductors constructed of modular elements. It is advantageous to use bar-core chokes.
Preferably, the bar-core choke is suspended in the mass center by means of a mounting plate. Suitably, the coil of the inductor consists of two windings, each having a trapezoidal cross section.
A static frequency converter would be suitable as a voltage source with variable frequency; the converter could be a direct converter built to act as an oscillating circuit converter, operating within the resonance frequency and with pulse-width control. At least one high-voltage capacitor may be connected in parallel to the insulation for the adjustment of the desired frequency. The advantage of this testing system for the testing of an insulation lies in the fact that this system permits testing with frequencies which are lower or higher than the line frequency. The testing system is small and very light-weight and contains elements which are more economical than was heretofore known.
27 Citations
19 Claims
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1. A high voltage testing system for testing the dielectric strength of electric insulation characterized by a capacitive reactance load by generating a rated KVA power in the form of a rated voltage and a rated current across the load, comprising:
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a power source for supplying a KVA power less than said rated KVA power; a transformer having a low voltage primary winding and a high voltage secondary winding, said secondary winding rated for a voltage less than said rated voltage and a current equal to the rated current of said reactance load; at least one high voltage inductor having a substantially constant inductance value connected in series between said reactance load and said secondary winding, said inductor rated to accept the rated current and rated voltage of said reactance load; and said inductor and said reactance load forming a tuned resonant circuit, and said power source having a continuously variable frequency tunable to the resonant frequency of said tuned resonant circuit; wherein the resonant circuit excited by said power source produces high reactive power at the rated KVA necessary to test said insulation, with said power source providing only the active power consumed by said resonant circuit; wherein said inductor comprises a serial connection of at least two high-voltage chokes with substantially constant inductance values, at least one of said chokes designed in the form of a bar-core choke. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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2. A high voltage testing system for testing the dielectric strength of electric insulation characterized by a capacitive reactance load by generating a rated KVA power in the form of a rated voltage and a rated current across the load, comprising:
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a power source for supplying a KVA power less than said rated KVA power; a transformer having a low voltage primary winding and a high voltage secondary winding, said secondary winding rated for a voltage less than said rated voltage and a current equal to the rated current of said reactance load; a least one high voltage inductor having a substantially constant inductance value connected in series between said reactance load and said secondary winding, said inductor rated to accept the rated current and rated voltage of said reactance load; and said inductor and said reactance load forming a tuned resonant circuit, and said power source having a continuously variable frequency tunable to the resonant frequency of said tuned resonant circuit; wherein the resonant circuit excited by said power source produces high reactive power at the rated KVA necessary to test said insulation, with said power source providing only the active power consumed by said resonant circuit; wherein said inductor comprises a parallel connection of at least two high-voltage chokes with substantially constant inductance values, at least one of said chokes designed in the form of a bar-core choke.
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3. A high voltage testing system for testing the dielectric strength of electric insulation characterized by a capacitive reactance load by generating a rated KVA power in the form of a rated voltage and a rated current across the load, comprising:
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a power source for supplying a KVA power less than said rated KVA power; a transformer having a low voltage primary winding and a high voltage secondary winding, said secondary winding rated for a voltage less than said rated voltage and a current equal to the rated current of said reactance load; a least one high voltage inductor having a substantially constant inductance value connected in series between said reactance load and said secondary winding, said inductor rated to accept the rated current and rated voltage of said reactance load; and said inductor and said reactance load forming a tuned resonant circuit, and said power source having a continuously variable frequency tunable to the resonant frequency of said tuned resonant circuit; wherein the resonant circuit excited by said power source produces high reactive power at the rated KVA necessary to test said insulation, with said power source providing only the active power consumed by said resonant circuit; wherein said inductor comprises a serial and parallel connection of at least two high-voltage chokes with at least substantially constant inductance values, at least one of said chokes designed in the form of a bar-core choke.
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Specification