Gas-Insulated Switchgear Layout With External Current Transformer
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Solution Overview
Problem
Conventional gas-insulated switchgear requires a large circuit breaker tank to accommodate an instrument current transformer, leading to increased size and maintenance complexities.
Innovation Solution
A gas-insulated switchgear design where the instrument current transformer is attached to a solid-insulated bus placed outside the circuit breaker tank, connected via a connection bushing, allowing for a reduced tank size and simplified maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the instrument current transformer is attached to the connection conductor inside the circuit breaker tank, then the transformer can be integrated with the circuit breaker, but the size of the circuit breaker tank is increased
Solution Approach 1:
The patent divides the system into two separate parts: the circuit breaker tank and the bus tank. The instrument current transformer is attached to the connection conductor in the bus tank rather than the circuit breaker tank, separating the functions and reducing the size of each individual tank while maintaining overall system functionality.
Solution Approach 2:
The instrument current transformer is extracted from the circuit breaker tank and relocated to the bus tank. This extraction allows the circuit breaker tank to be reduced in size while the transformer remains integrated into the overall switchgear system through the connection conductor.
2Power
If two or more power cables are used to achieve large rated current, then the current capacity is increased, but the complexity of attaching instrument current transformers is increased
Solution Approach 1:
Multiple power cables are merged and integrated at a single connection conductor inside the bus tank. This consolidation allows multiple cables carrying large currents to be connected to one transformer, simplifying the attachment process while maintaining the required current capacity.
Solution Approach 2:
The connection conductor in the bus tank serves multiple functions: it connects multiple power cables, provides a mounting point for the instrument current transformer, and facilitates simplified maintenance. This multi-functionality reduces the overall complexity of the system.
3Adaptability or versatility
If the instrument current transformer is attached inside the circuit breaker tank, then the transformer is integrated with the circuit breaker, but maintenance requires gas processing which complicates the maintenance process
Solution Approach 1:
The system is segmented into the circuit breaker tank and the bus tank, with the instrument current transformer located in the bus tank. This segmentation allows maintenance of the transformer to be performed independently without requiring gas processing of the circuit breaker tank, simplifying the maintenance process.
Solution Approach 2:
The instrument current transformer is extracted from the circuit breaker tank and placed in the bus tank, which contains atmospheric air rather than insulating gas. This extraction enables maintenance workers to service the transformer without complex gas handling procedures, significantly improving ease of repair.
Data Source
AI summary
Provided is a gas-insulated switchgear having a circuit breaker tank with a reduced size. The gas-insulated switchgear includes: a connection conductor connected to two or more power cables, for each phase, inside the circuit breaker tank; a solid-insulated bus placed outside the circuit breaker tank and connected to the connection conductor via a connection bushing; and an instrument current transformer attached to the solid-insulated bus.