Load Tap Changer With Semiconductor Switching
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Solution Overview
Problem
Existing load tap changers for voltage regulation in power grids face challenges such as high costs, maintenance requirements, and energy losses due to mechanical on-load tap changers, while electronic on-load tap changers are costly due to semiconductor switches, and both types have limitations in flexibility and efficiency.
Innovation Solution
A load tap changer system that combines a mechanical switch with a semiconductor switch and an impedance or uncontrolled semiconductor switch, allowing for efficient tap changes with reduced maintenance and energy losses by sequencing the connection and disconnection of these components during voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical on-load tap changers are used, then in-service operation is enabled, but the device becomes large, heavy, expensive, and requires frequent maintenance
Solution Approach 1:
The patent divides the switching function into two separate components: a mechanical switch for main power interruption and semiconductor switches for precise tap selection. This segmentation allows each component to perform its specialized function efficiently, eliminating the need for complex mechanical mechanisms to handle both switching and precision selection
Solution Approach 2:
The patent replaces mechanical switching mechanisms with semiconductor switches for the tap selection function. The semiconductor switches electronically control the connection between taps and the load, eliminating mechanical wear and reducing the complexity of mechanical components while maintaining in-service operation capability
2Ease of operation
If mechanical on-load tap changers are used, then in-service operation is enabled, but maintenance requirements increase and lifetime tap changes are limited
Solution Approach 1:
The patent replaces mechanical switching mechanisms with semiconductor switches for the tap selection function. The semiconductor switches electronically control the connection between taps and the load, eliminating mechanical wear and reducing the complexity of mechanical components while maintaining in-service operation capability
Solution Approach 2:
The patent introduces an impedance component as an intermediary element that facilitates smooth transition during tap changing. This impedance component helps manage the switching transient and protects both the mechanical and semiconductor switches from excessive stress, thereby reducing maintenance requirements
3Reliability
If electronic on-load tap changers with semiconductor devices are used, then maintenance requirements are reduced, but cost increases due to semiconductor switches
Solution Approach 1:
The patent divides the switching function into two separate components: a mechanical switch for main power interruption and semiconductor switches for precise tap selection. This segmentation allows each component to perform its specialized function efficiently, eliminating the need for complex mechanical mechanisms to handle both switching and precision selection
Solution Approach 2:
The patent applies different switching technologies in different locations within the system: mechanical switches are used where high-power interruption is needed, while semiconductor switches are used where precise control and low maintenance are required. This localized application optimizes the overall system performance and cost-effectiveness
4Device complexity
If off-load tap changers are used, then cost is reduced, but load disconnection is required for each operation
Solution Approach 1:
The patent introduces an impedance component as an intermediary element that facilitates smooth transition during tap changing. This impedance component helps manage the switching transient and protects both the mechanical and semiconductor switches from excessive stress, thereby reducing maintenance requirements
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 system achieves significant maintenance reduction and higher efficiency with lower losses, reducing costs and enabling more flexible voltage regulation in power grids.
Implementation Method 1
a mechanical switch connected to a power terminal of a voltage conversion device to carry an electric current
Implementation Method 2
a semiconductor switch connected between the first tap and the power terminal of the voltage conversion device
Implementation Method 3
an impedance branch connected between the second tap and the power terminal of the voltage conversion device
Data Source
AI summary
A load tap changer includes a mechanical switch, a semiconductor switch and an impedance branch or an uncontrolled semiconductor switch. The mechanical switch is connected to a power terminal of a voltage conversion device to carry an electric current and is activated to switch from a first tap to a second tap of the voltage conversion device when a tap change signal is received. The semiconductor switch is then connected between the first tap and the power terminal of the voltage conversion device and is disconnected before the mechanical switch is connected to the second tap. The impedance branch or the uncontrolled semiconductor switch is connected between the second tap and the power terminal of the voltage conversion device before the mechanical switch is connected to the second tap. The impedance or the uncontrolled semiconductor switch is disconnected after the mechanical switch is connected to the second tap.