Electrical Winding Surge Testing with Local Resistance Damping
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Solution Overview
Problem
Surge testing of electrical insulation in windings of electrical machines is compromised by unwanted high-frequency oscillations due to parasitic inductance and capacitance, leading to inaccurate voltage application and calibration issues.
Innovation Solution
A damping device comprising a resistance is connected in parallel across the winding under test, with test connections arranged to form a parallel combination with the winding, effectively damping these oscillations by positioning the damping device near the winding rather than the test device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surge generator connected by long test leads is used to apply high voltage impulses to test windings, then the insulation can be tested, but parasitic inductance and capacitance cause unwanted high frequency oscillations that make the test difficult to calibrate and may apply greater voltages than intended
Solution Approach 1:
The damping device is extracted as a separate component that can be connected in parallel with the winding under test. This removes the oscillation problem from the test setup by providing a dedicated damping path that does not interfere with the surge generator or test leads
Solution Approach 2:
The damping device acts as an intermediary element between the surge generator and the winding under test. It mediates the energy transfer by absorbing oscillations while allowing the intended voltage impulse to pass through to test the insulation
2Object-generated harmful factors
If a damping device is connected at the end of test connections nearest to the test device, then some damping effect is achieved, but the damping is less effective compared to connecting the damping device directly across the winding under test
Solution Approach 1:
The damping device is placed locally at the winding under test rather than at the test device end. This local placement ensures that damping occurs exactly where the oscillations are generated, maximizing effectiveness while keeping the connection arrangement simple
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces unwanted oscillations, ensuring accurate voltage application and calibration, allowing for safer and more reliable surge testing of electrical insulation.
Implementation Method 1
a damping device comprising a resistance... effectively damping these oscillations
Implementation Method 2
parasitic inductance and capacitance in the test set up and the device under test, typically the windings and/or coils of an electrical machine, may lead to unwanted high frequency oscillations... Arranging for the test connections to connect a parallel combination of the damping device and the part of the winding under test to the test device allows more effective damping of oscillation
Data Source
AI summary
A method of operation and apparatus is provided for performing a surge test of electrical insulation of at least part of a winding under test, the winding being a winding of an electrical machine. The apparatus comprises a test device having a surge generator, at least two test connections for connecting to the test device, and a damping device comprising a resistance. The damping device is connected across the part of the winding under test, the test connections are arranged to connect a parallel combination of the damping device and the part of the winding under test to the test device and a voltage impulse is generated using the surge generator.