Telescopic Disconnector Switch for Compact Three-Position Earthing
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Solution Overview
Problem
Existing switchgears face challenges in providing a reliable and compact design with a small footprint, while ensuring improved dielectric performance and ease of maintenance, particularly in achieving a three-position disconnector and earthing switch configuration.
Innovation Solution
The implementation of a telescopic or retractable contact in the disconnector and earthing switch, which allows the disconnector blade to pivot between three positions, including a closed, isolation, and earthed position, utilizing a compliant member to adjust the blade's length and an insulating support to reduce dielectric failure risks, thereby maintaining adequate clearance and improving dielectric performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a three-position disconnector and earthing switch is provided, then the ease of maintenance and in-situ testing is improved, but the device complexity increases
Solution Approach 1:
The patent combines the disconnector switch and earthing switch into a single integrated device with a common operating mechanism. The single disconnector blade serves dual functions: acting as a live conductor in the closed position and as an earthing conductor when connected to the earthing contact, thereby merging two separate switching functions into one device.
Solution Approach 2:
The disconnector blade is designed to perform multiple functions: it serves as the live conductor during normal operation, becomes the earthing conductor when connected to the earthing contact, and provides mechanical linkage for the operating mechanism. This multi-functionality reduces the need for separate dedicated components.
2Volume of moving object
If the disconnector blade is made telescopic, then the footprint of the switchgear is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The disconnector blade is designed as a telescopic structure that dynamically changes its length based on the switch position. In the closed position, the blade is extended to maintain adequate clearance from the earthing contact. In the isolated position, the blade is retracted to minimize the footprint and allow the operating mechanism to maneuver. This dynamic adjustment resolves the conflict between maintaining clearance and reducing footprint.
Solution Approach 2:
The telescopic blade employs a nested structure where one portion of the blade is inserted within another portion, allowing the blade to compact into a smaller volume when retracted. This nesting arrangement enables the blade to achieve both extended and retracted configurations within a compact overall structure.
3Reliability
If the disconnector blade is retracted in the isolated position, then the dielectric performance is improved, but the clearance maintenance becomes more difficult
Solution Approach 1:
The operating mechanism is designed to automatically control the telescopic blade's extension and retraction based on the switch position. When transitioning to the isolated position, the mechanism automatically retracts the blade to the appropriate degree, eliminating the need for manual adjustment or complex external control systems. The blade self-adjusts its length in response to the mechanism's operation.
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 facilitates a compact and reliable switchgear with improved dielectric performance, enabling easier in-situ testing and maintenance, while reducing the risk of dielectric failure.
Implementation Method 1
a compliant member disposed within the guide hole and configured to bias the inner contact out of the guide hole. Optionally, in response to an external force applied in a first direction and to the second end of the disconnector blade, the inner contact is configured to slide in the first direction within the guide hole of the outer contact and the compliant member is configured to bias the inner contact in a direction opposite the first direction. Optionally, the compliant member is a compression spring.
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
Disclosed herein is a device (100, 200) comprising. The device (100, 200) comprises: one or more switching mechanisms (110) configured to disconnect a power supply from a load; and one or more disconnector and earthing switches (330), each disconnector and earthing switch (330) associated with a respective switching mechanism (110). Each disconnector and earthing switch (330) comprising a telescopic disconnector blade (332, 432) having a first end and a second end, wherein the disconnector blade (332, 432) is configured to pivot around the first end between three different positions. The three positions comprise: a first position in which the disconnector and earthing switch (330) is closed and the power supply is connected to the load through the disconnector blade (332, 432); a second, isolation, position in which the disconnector and earthing switch (330) is open and the power supply is disconnected from the load; and a third position in which the power supply is disconnected from the load and a second end of the disconnector blade (332, 432) is electrically connected to an earthing contact (336). Such a disconnector and earthing switch (330) (also termed an earthing disconnection switch) can be termed a 3PS switch (three position disconnector and earthing switch).