Box-Type Substation Mechanical Interlock for Faster Transformer Maintenance
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Solution Overview
Problem
The interlocking design of box-type substations is complex, requiring maintenance personnel to read operation guides, which hinders quick maintenance and increases time during emergencies, affecting maintenance efficiency and safety.
Innovation Solution
A simplified mechanical lock interlocking system with keychains and locks that ensure circuit breakers, disconnectors, and grounding switches are sequentially operated, allowing for quick and safe maintenance without guides, using keychains that are locked to their respective components to enforce the correct sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex interlocking logic with operation guides is used, then safety of maintenance personnel is ensured, but maintenance efficiency is reduced and operation time increases
Solution Approach 1:
The interlocking system is segmented into multiple independent keychains, each controlling specific circuit breakers and disconnectors. The first keychain controls the first and second circuit breakers, while the second keychain controls the first and second disconnectors. This segmentation allows maintenance personnel to access different components independently, reducing the time required to reach the transformer room while maintaining safety through distributed control.
Solution Approach 2:
The keychains are designed to be obtained in advance under specific conditions: the first keychain can be obtained only after the first circuit breaker is switched off, and the second keychain can be obtained only after the second circuit breaker is switched off. This preliminary action ensures that safety conditions are met before maintenance personnel can access the transformer room, maintaining reliability while streamlining the process.
2Reliability
If complex interlocking logic is used, then safety is ensured, but device complexity increases and materials are consumed
Solution Approach 1:
The interlocking system is divided into modular keychains with distinct functions. The first keychain manages circuit breaker control, while the second keychain manages disconnector control. This modular segmentation simplifies the overall design by breaking down the complex interlocking logic into manageable, independent units, reducing device complexity while maintaining safety.
Solution Approach 2:
Each keychain serves multiple functions: the first keychain controls both the first and second circuit breakers, and the second keychain controls both the first and second disconnectors. This multi-functionality reduces the total number of control devices needed, simplifying the interlocking design while ensuring comprehensive safety control.
3Reliability
If traditional logic locks are used, then safety interlocking is achieved, but ease of operation is reduced and personnel training is required
Solution Approach 1:
The control system is segmented into intuitive keychain units that physically represent different safety levels. Maintenance personnel can easily understand and operate the system by obtaining the appropriate keychain based on the current system state, eliminating the need to read complex operation guides while maintaining safety interlocking.
Solution Approach 2:
The system provides self-service through automatic keychain distribution based on system state. When circuit breakers are switched off, the corresponding keychains become available for retrieval. This self-service mechanism guides personnel through the safety process without requiring external instructions, improving ease of operation while ensuring safety compliance.
Data Source
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AI summary
This application discloses a box-type substation, an energy storage power supply system, and a photovoltaic power generation system. The box-type substation includes a low-voltage cabinet, a high-voltage cabinet, a transformer, a first keychain, and a second keychain. When two circuit breakers in the low-voltage cabinet are in a switched-on state, each of the first keychain and the second keychain is locked at a corresponding circuit breaker. Therefore, when maintenance is performed on the transformer, the circuit breakers in the low-voltage cabinet are switched off first to remove the first keychain and the second keychain. Then, the first keychain and the second keychain are used together to switch off a disconnector in the high-voltage cabinet, and the first keychain and the second keychain are locked at the disconnector when the disconnector is in a switched-off state. Mechanical lock logic of the box-type substation is simple, and maintenance personnel can quickly switch off the circuit breakers and the disconnector. This can improve maintenance efficiency of the transformer while ensuring safety of the maintenance personnel, and improve running reliability of an energy storage system and a photovoltaic power generation system for which the box-type substation is used.