Vacuum Interrupter Polarity Switching for Control Transformers
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Solution Overview
Problem
Existing switching arrangements for control transformers can cause decomposition and gas formation in insulating oil when polarity resistors are switched on and off, leading to contamination and reduced lifespan of the tap changer or regulating transformer.
Innovation Solution
A switching arrangement that includes a vacuum interrupter in series with a resistor and an isolation switch, connected between a first terminal and a second terminal, which reduces or avoids decomposition and gas formation by using a vacuum interrupter to manage the switching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarity resistors are switched on and off using conventional switches in insulating oil, then the switching function is achieved, but arc occurs causing decomposition and gas formation in the insulating oil
Solution Approach 1:
A vacuum interrupter is introduced as an intermediary switching device between the polarity resistors and the insulating oil environment. The vacuum interrupter performs the switching operation in a vacuum atmosphere, preventing direct contact between the arc and insulating oil, thereby eliminating gas formation and decomposition products while maintaining the polarity switching function
Solution Approach 2:
The switching operation is transferred from the insulating oil environment to a vacuum environment. The vacuum acts as an inert atmosphere that does not support arc-induced decomposition reactions, thus preventing the formation of harmful gases and chemical products during the switching process
2Ease of operation
If polarity resistors are switched using conventional switches, then the switching operation is performed, but arc causes contamination of insulating oil
Solution Approach 1:
The vacuum interrupter serves as a mediator that isolates the switching arc from the insulating oil. It enables the switching operation to be performed without direct interaction between the arc and the oil, thus preventing contamination while maintaining operational simplicity
Solution Approach 2:
The switching system is segmented into two distinct functional zones: the vacuum interrupter zone for arc-containing switching operations, and the insulating oil zone for electrical insulation. This segmentation prevents the harmful effects of the arc from affecting the insulating oil while maintaining both functions
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
The proposed solution enables trouble-free and gas-free operation of the control transformer by minimizing the decomposition of insulating oil during resistor switching, thereby extending the lifespan of the transformer.
Implementation Method 1
a vacuum interrupter; wherein the first terminal is connected to the second terminal via the series connection
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
A switching arrangement (1), in particular a polarity switching means, for a control transformer (10) which comprises a first winding (2) for a phase of an AC power supply system, which phase is to be controlled, comprises - a first connection terminal (1.1) which can be connected to the winding (2); - a second connection terminal (1.2) which can be connected to a discharge line (3); - a vacuum interrupter (4); - an isolator (5); - a resistor (6) which is connected in series with the vacuum interrupter (4) and the isolator (5); wherein - the first connection terminal (1.1) is connected to the second connection terminal (1.2) by means of the series circuit.