Motor-Driven Tap Changer Switching with Kinetic Energy Storage

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Solution Overview

Problem

Existing load-operated tap changers rely on spring energy storage for actuation, lacking control over the energy required for switching operations, leading to inefficiencies and potential overloading of components.

Innovation Solution

A switching unit that utilizes a drive system with a motor mechanically coupled to a load tap changer, where an actuating shaft stores kinetic energy and is used to actuate switching elements, optimizing energy use and preventing motor speed drops below a minimum value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If spring energy storage devices are used to actuate the load tap changer, then the switching operation can be performed, but the energy required for switching cannot be controlled and components may be overloaded

Engineering Contradiction:
Improveenergy control for switchingVSAvoidcomponent overload protection
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent removes the spring energy storage device from the system and replaces it with a motor-driven actuating shaft. This extraction eliminates the uncontrolled energy release characteristic of springs, allowing for controlled energy delivery through the motor while preventing component overload.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The control unit monitors the motor speed and switching position continuously, enabling real-time feedback control. This ensures that the energy delivered during switching is precisely controlled and that the motor speed remains within safe operating limits, preventing component overload.

Inventive Principle:
Principle #23Feedback

2Productivity

If a motor is sized to ensure minimum speed during switching, then switching times are met, but the motor becomes oversized and costly

Engineering Contradiction:
Improveswitching time complianceVSAvoidmotor cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The control unit pre-calculates the optimal motor speed profile before switching begins. By planning the acceleration and deceleration phases in advance, the system ensures switching time compliance is achieved efficiently without requiring an oversized motor capable of maintaining minimum speed throughout the entire operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The motor operates in periodic cycles of acceleration, constant speed, and deceleration rather than maintaining continuous minimum speed. This periodic operation allows the motor to be sized for peak performance during switching moments rather than continuous operation at minimum speed, reducing overall motor size and cost.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If the actuating shaft is used as kinetic energy storage, then energy efficiency is improved, but the shaft must be precisely matched to the switching elements

Engineering Contradiction:
Improveenergy efficiencyVSAvoidmass matching complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The control unit continuously monitors the motor speed and adjusts the energy delivery to the actuating shaft in real-time. This feedback control compensates for variations in the shaft's moment of inertia and ensures optimal energy transfer, reducing the sensitivity to precise mass matching while maintaining high energy efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from a static spring energy storage system to a dynamic motor-driven system with variable speed control. The motor can adjust its output dynamically to match the instantaneous energy requirements of the switching elements, making the system more adaptable to variations in shaft mass and reducing the need for precise pre-matching.

Inventive Principle:
Principle #15Dynamics

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

Ensures efficient and safe switching operations by maintaining motor speed, preventing overcurrents, and reducing component stress, resulting in a cost-effective design.

Implementation Method 1

the drive system uses the actuating shaft as a storage device for kinetic energy, such that the actuating shaft is accelerated and the switching device is actuated by means of kinetic energy from the actuating shaft

Methodology Applied
Scientific EffectKinetic energy storage: Inertia

Data Source

PatentEP4338181B1Switch unit
Publication Date: 2025.11.19 REINHAUSEN GMBH
  • EP4338181B1 patent drawingFigure 1
  • EP4338181B1 patent drawingFigure 2
  • EP4338181B1 patent drawingFigure 3a

AI summary

The invention relates to a switch unit (1), comprising: - an on-load tap changer (17) having an actuating shaft (20) which actuates a switching means (21), and a drive system (3) having a motor (12); the drive system (3) being mechanically coupled to the on-load tap changer (17) and actuating it and, during actuation of the on-load tap changer (17), the drive system (3) using the actuating shaft (20) as a storage means for kinetic energy in such a way that the actuating shaft (20) is accelerated and the switching means (21) is actuated by means of kinetic energy from the actuating shaft (20) and additional energy which is provided by the motor (12).