On-Load Tap Changer Using Semiconductor Diverter Switching
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Solution Overview
Problem
The design of on-load tap-changers based on the high-speed resistor switching principle is complex and affects the structural design, requiring different resistor configurations for varying load currents and step voltages, which complicates installation space and component design.
Innovation Solution
The use of semiconductor switching elements in diverter switches eliminates the need for ohmic resistors, allowing a unified design for a selected power range, with independent selector arms and multiple paths for seamless switching between winding taps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ohmic resistors are used to limit circulating current during switching, then switching between winding taps can be performed under load, but the design becomes complex and affects structural design requiring different resistor configurations for varying load currents and step voltages
Solution Approach 1:
The patent replaces the mechanical/ohmic resistor-based current limiting system with a semiconductor switching element (IGBT) that uses electronic control to limit circulating current. The IGBT is controlled to open at the zero crossing of the step voltage, providing current limitation without requiring complex resistor networks. This substitution of mechanical/ohmic components with electronically controlled semiconductor devices resolves the contradiction by maintaining reliable switching while eliminating design complexity.
2Adaptability or versatility
If different resistor configurations are used for varying load currents and step voltages, then the on-load tap-changer can be adapted to specific applications, but the installation space and structural design are affected
Solution Approach 1:
The patent implements a universal design where a single on-load tap-changer configuration with semiconductor switching elements can handle varying load currents and step voltages without requiring different resistor configurations. The IGBT-based diverter switch provides a unified solution that replaces multiple application-specific resistor designs, thereby reducing installation space while maintaining adaptability through electronic control rather than physical component variation.
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 approach simplifies the design, enabling adaptable and efficient switching without complex resistor configurations, suitable for a wide range of load currents and step voltages.
Implementation Method 1
The semiconductor switching element is configured to open at a zero crossing of the step voltage
Data Source
AI summary
An on-load tap-changer uninterruptedly switches between winding taps of a tap-changing transformer. The on-load tap-changer has: a diverter switch that switches over from a first to a second fixed contact; and a selector that powerlessly preselects the fixed contacts and has a first and second selector arm that are actuated independently and contact each of the fixed contacts. The diverter switch has: a main path with a mechanical switching element that connects the first selector arm to a load take-off lead; a first auxiliary path with a first semiconductor switching element that is parallel to the main path and connects the first selector arm to the load take-off lead, and a second auxiliary path with a second semiconductor switching element that connect the second selector arm to the load take-off lead.