Railcar Transformer HV Cable Connection Structure
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Solution Overview
Problem
The existing connection structure between a main transformer and a high-voltage device box in railcars is hindered by a large and heavy insulating protective tube, leading to low workability during maintenance, poor vibration followability, limited layout flexibility, and design constraints due to size and mass limitations, as well as issues with car gauge and device positioning.
Innovation Solution
A connection structure utilizing first and second connector devices at the high-voltage device box and main transformer, respectively, with a high-voltage cable having cable connector portions that fit and connect to these devices, allowing for improved workability, vibration followability, and layout flexibility, eliminating the need for a large insulating protective tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating protective tube is used to protect electric wires and prevent electric shock, then safety and insulation are improved, but the size and mass increase significantly
Solution Approach 1:
The patent extracts the insulating protective tube from the system and replaces it with a combination of an insulator-type cable head and connection electric wires that inherently provide insulation. The cable head with its insulating structure performs the protection function without requiring a separate large metal tube, thereby eliminating the mass penalty while maintaining safety.
Solution Approach 2:
The insulator-type cable head acts as an intermediary component between the power cable and the connection electric wires. It provides the necessary insulation and electrical connection function, serving as a compact mediator that replaces the bulky insulating protective tube while achieving the same safety objectives.
2Reliability
If an insulating protective tube is used to secure insulation distance, then electric shock prevention is improved, but workability during maintenance deteriorates
Solution Approach 1:
The patent segments the connection system into modular components: an insulator-type cable head, connection electric wires, and connector devices. This segmentation allows individual components to be easily attached and detached without moving a large integrated insulating protective tube, significantly improving maintenance workability while preserving electric shock prevention through the insulator-type cable head.
Solution Approach 2:
The patent introduces flexible connection electric wires that can dynamically adjust to relative position changes between devices due to vibrations. This dynamic flexibility eliminates the need for a rigid, large insulating protective tube that would restrict movement, thereby improving ease of operation during maintenance while maintaining insulation safety.
3Reliability
If a large insulating protective tube is used, then insulation distance is secured, but layout flexibility of underfloor devices is limited
Solution Approach 1:
The patent changes the insulation parameter from a fixed, large physical barrier (insulating protective tube) to a flexible electrical insulation solution (insulator-type cable head with connection wires). This parameter change allows the insulation function to be maintained while enabling greater layout flexibility, as the connection system can now accommodate relative position changes and various device arrangements without being constrained by a large rigid tube.
Solution Approach 2:
The patent transitions from a three-dimensional rigid insulating protective tube to a more flexible connection system that can adapt to dimensional changes in device positions. The flexible connection electric wires and compact cable head provide insulation in a manner that accommodates spatial variations, thereby improving layout flexibility while maintaining the necessary insulation distance through the insulator-type cable head.
4Strength
If the insulating protective tube is made of metal, then structural strength is improved, but mass increases
Solution Approach 1:
The patent employs composite material principles by using an insulator-type cable head made of insulating materials (such as plastic or ceramic) combined with metal connection components. This composite approach provides sufficient structural strength for electrical connection and insulation without the excessive mass of a complete metal insulating protective tube, achieving an optimal balance between strength and weight.
Data Source
AI summary
A connection structure includes: a circuit breaker connected to a power cable through which high-voltage power is supplied; a high-voltage device box accommodating the circuit breaker; a main transformer configured to transform a voltage of the high-voltage power and provided under the floor of the car; a first connector device electrically connected to the circuit breaker and provided at a dividing wall of the high-voltage device box; a second connector device electrically connected to the main transformer and provided at a dividing wall of the main transformer; and a high-voltage cable covered with an insulating coating and having both end portions to which cable connector portions are respectively attached, wherein the high-voltage cable connects the first connector device and the second connector device in such a manner that the cable connector portions respectively fit and are connected to the first connector device and the second connector device.