Mica Insulation Tree Testing With Needle Electrode Assembly
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Solution Overview
Problem
Current insulation testing methods, such as those proposed by IEC, often fail to reproduce and analyze electrical trees in mica insulation systems effectively, as they break down during testing and do not allow for detailed observation of the tree's behavior, limiting the understanding of their development mechanism.
Innovation Solution
An electrical tree test method involving an electrode setting assembly with needle electrodes and insulation spacers is used to apply voltage to a mica insulation system, allowing for the reproduction and observation of electrical tree behavior by impregnating the insulation with synthetic resin and carefully controlling the electrode positions to prevent external forces on the insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plate-like electrodes are used for insulation testing, then the testing can be performed according to IEC standards, but the electrical trees are broken during testing and no trace remains for observation
Solution Approach 1:
The electrode structure is segmented into multiple needle electrodes arranged in a specific pattern, allowing the electrical tree to develop between individual needles rather than being compressed between flat plates. This segmentation enables the tree structure to be preserved and observed after breakdown.
Solution Approach 2:
The testing method transitions from two-dimensional plate electrodes to a three-dimensional needle electrode arrangement. This dimensional change creates space for the electrical tree to develop and be preserved in a manner that maintains its structural characteristics for observation.
2Ease of manufacture
If plate-like electrodes are used, then standard testing can be performed, but the starting positions of electrical trees are indefinite and mechanism analysis is limited
Solution Approach 1:
The needle electrodes are arranged with specific spacing and configuration to create localized high-field regions at defined positions. This allows the starting positions of electrical trees to be controlled and precisely identified, enabling detailed mechanism analysis while maintaining testing validity.
3Reliability
If voltage is applied to mica insulation system, then electrical tree development can be observed, but the insulation breaks down and cannot be reused for detailed observation
Solution Approach 1:
The mica insulation is impregnated with synthetic resin before the electrical tree test. This preliminary action reinforces the insulation structure, allowing it to withstand the breakdown process while preserving the electrical tree trace for detailed observation and analysis.
Solution Approach 2:
The insulation system becomes a composite structure combining mica insulation with synthetic resin impregnation. This composite material provides both the electrical properties needed for tree development and the mechanical strength needed to preserve the tree structure after breakdown.
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 enables the detailed reproduction and confirmation of electrical tree behavior in mica insulation systems, providing insights into their development and helping to prevent breakdowns in rotating electrical machines.
Implementation Method 1
If a non-uniform electric field is generated at a part of the insulation and the intensity of the non-uniform electric field exceeds the dielectric strength-limit voltage when an electric field is applied to the insulation
Implementation Method 2
an impregnation step of impregnating the mica insulation with synthetic resin after the set setting step
Data Source
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AI summary
This electrical tree test method is a method for testing for electrical trees in an insulating member including a mica insulation applied to an electrical conductor. The method comprises: an assembly setting step (S03) of setting an electrode setting assembly to the outside of the mica insulation; an impregnation step (S04) of impregnating the mica insulation with synthetic resin after the assembly setting step; a removal step (S05) of removing components of the electrode setting assembly, except an electrode structure, after the impregnation step (S04); a power supply connecting step (S06) of connecting, after the removal step (S05), the electrical conductor and the electrode structure to a power supply in order to apply a voltage between the electrical conductor and the electrode structure; and a voltage applying step (S07) of applying a voltage between the electrical conductor and the electrode structure, after the power supply connecting step (S06).