On-Load Tap Changer With Self-Powered Uninterrupted Switching
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Solution Overview
Problem
Existing on-load tap-changers face challenges in switching between transformer winding taps without interruption, requiring separate power supplies for mechanical and power electronic switching means.
Innovation Solution
An on-load tap-changer design that uses fixed contacts, selector arms, and a diverter switch with semiconductor switching elements, where the control unit is powered by a step voltage generated during switching, eliminating the need for external power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate power supplies are provided for mechanical and power electronic switching means, then reliable operation is ensured, but device complexity increases
Solution Approach 1:
The patent combines the power supply function into the main transformer by utilizing the transformer windings themselves to generate control power. The control unit is powered by a control winding that is part of the transformer structure, eliminating the need for separate external power supplies for both mechanical and power electronic switching means.
Solution Approach 2:
The transformer serves multiple functions: it transforms power, provides isolation, and generates control power through its control winding. This multi-functionality allows the system to operate reliably while reducing external connections, as the same transformer structure that provides power transformation also supplies power to the control unit.
2Productivity
If external power supply is used for control unit, then uninterrupted switching is enabled, but ease of operation deteriorates
Solution Approach 1:
The control unit is self-powered through the control winding of the transformer. The system uses its own operational energy (the transformer's magnetic field and windings) to supply power to the control electronics, eliminating the need for external power connections and simplifying operation.
Solution Approach 2:
The control power supply is extracted from the external environment and integrated into the transformer structure itself. By taking the power supply function out of the external system and embedding it within the transformer, the patent eliminates external power connections while maintaining uninterrupted switching capability.
3Productivity
If hybrid switching means with mechanical contacts and semiconductor elements are used, then uninterrupted switching between taps is achieved, but device complexity increases
Solution Approach 1:
The switching function is segmented into two independent parts: mechanical switching means for tap selection and power electronic switching means for load commutation. This segmentation allows each subsystem to perform its specific function optimally while being controlled by a unified control unit, achieving uninterrupted switching without excessive complexity.
Solution Approach 2:
The control unit acts as an intermediary that coordinates both mechanical and power electronic switching means. By centralizing control logic, the system manages the complexity of hybrid switching through a single control intelligence that sequences operations to achieve uninterrupted tap changing.
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
Enables uninterrupted switching between transformer taps with a self-powered control system, ensuring reliable operation and reducing the complexity of external power connections.
Implementation Method 1
the control unit is powered by a step voltage generated during switching
Data Source
AI summary
An on-load tap-changer switches, without interruption, between winding taps of a tapped transformer. The on-load tap-changer includes fixed contacts, which include a first fixed contact, which is configured to connect to a first winding tap of the tapped transformer; and a second fixed contact, which is configured to connect to a second winding tap of the tapped transformer. The on-load tap-changer also includes a first selector arm, which is configured such that it can contact each of the fixed contacts; a second selector arm, which is configured such that it can contact each of the fixed contacts; and a diverter switch configured to perform a switch from the first fixed contact to the second fixed contact of the on-load tap-changer; a connection contact arranged additionally to the fixed contacts; and an auxiliary contact, which configured to selectively contact the connection contact or one of the fixed contacts.