Hybrid DC Circuit Breaker with Commutation Device
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Solution Overview
Problem
Direct-current transmission systems face challenges in efficiently isolating accident currents due to the lack of current-zero points, leading to high conduction losses and increased costs, especially in large-scale power transmission networks.
Innovation Solution
A direct-current interrupting device comprising a mechanical breaker, a semiconductor breaker, and a commutation device, where the mechanical breaker handles regular current transmission and the semiconductor breaker blocks accident currents after creating zero points through a commutation process, reducing conduction losses and infrastructure requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semiconductor breaker is used to independently block direct current, then the ability to block accident current is improved, but conduction loss increases and transmission efficiency decreases
Solution Approach 1:
The breaker is divided into two distinct functional parts: a mechanical-contact-type disconnecting switch for normal current conduction and a semiconductor breaker for accident current blocking. This segmentation allows each component to be optimized for its specific function, with the mechanical switch handling low-loss normal operation and the semiconductor device handling high-reliability fault interruption.
Solution Approach 2:
The hybrid breaker structure enables the system to perform multiple functions: normal power transmission through the mechanical switch and accident current blocking through the semiconductor breaker. The parallel configuration allows the system to adapt between these two operational modes, achieving both efficiency and reliability.
2Loss of energy
If a hybrid breaker with mechanical-contact-type disconnecting switch and auxiliary semiconductor breaker is used, then conduction loss is reduced compared to full semiconductor breaker, but conduction loss of auxiliary semiconductor breaker still occurs
Solution Approach 1:
The auxiliary semiconductor breaker is extracted from the normal current path and placed in parallel with the mechanical disconnecting switch. This extraction allows the mechanical switch to carry all normal current without semiconductor conduction losses, while the semiconductor breaker remains available for fault conditions.
3Loss of energy
If a direct-current interrupting device with mechanical breaker, semiconductor breaker, and transferring circuit is used, then conduction loss is greatly reduced, but device complexity and infrastructure size increase
Solution Approach 1:
The mechanical breaker and semiconductor breaker are merged into a single hybrid breaker unit with integrated circuitry. The transferring circuit is combined with the semiconductor breaker components, creating a unified device that reduces overall complexity compared to separate systems while maintaining low conduction loss through the mechanical contact path.
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 configuration significantly reduces conduction losses and minimizes the size and cost of the infrastructure needed for the direct-current interrupting device, enhancing the efficiency and cost-effectiveness of power transmission.
Implementation Method 1
the commutation device makes the current flowing through the current interrupting contact temporarily zero by generating zero points in the current flowing through the mechanical breaker through a commutation process
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
According to the embodiments, a direct-current interrupting device includes a mechanical breaker (2), a semiconductor breaker (3), and a commutation device (4). The mechanical breaker (2) comprises a mechanical contact (6) made by connecting a high-voltage contact and a current interrupting contact in series, and bushings (8) which are connected to a pressure vessel (5) equipotential to the ground potential and electrically connect the both ends of the mechanical contact (6) and a direct-current transmission system. The commutation device (4) is connected to at least the high-voltage contact of a high-voltage contact and a current interrupting contact in parallel, and is connected to the semiconductor breaker (3) in series. The direct-current interrupting device opens the path of the mechanical contact (6) when an accident occurs in the direct-current transmission system to make a semiconductor stack (31) in a current-carrying state, and make the current flowing through the mechanical breaker (2) temporarily zero by the commutation device (4), thereby transferring the accident current from the mechanical breaker (2) to the semiconductor breaker (3). The direct-current interrupting device sets the semiconductor stack (31) to a blocking state after the transference, thereby blocking the accident current.