Dry Cable Fitting With Inverted Stress Control
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Solution Overview
Problem
Existing high voltage cable termination solutions are cumbersome to install, require field testing, and often result in longer cable lengths due to the need for stress control elements and filling limitations, which can lead to electrical breakdowns.
Innovation Solution
A dry-type cable fitting with a tubular outer insulator, preinstalled connecting element, and elastomeric joint body insulator, featuring a sliding contact and insulating filling, which allows for easy installation and compact design while maintaining electrical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stress control element is arranged inside the insulator housing, then electrical breakdown is prevented, but the installation accessibility and control of correct placement are severely limited
Solution Approach 1:
Instead of placing the stress control element inside the insulator housing where it is protected but difficult to access, the invention inverts the arrangement by placing the stress control element outside the insulator housing. This allows the element to be easily accessible for installation and adjustment while still providing the necessary electrical field control through the insulator housing structure.
2Reliability
If the filling level is increased above the stress control element, then dielectric strength is improved, but the insertion of the cable is hindered
Solution Approach 1:
The invention inverts the traditional arrangement by positioning the stress control element below the filling level rather than above it. This allows the filling to extend to a higher level for improved dielectric strength while the stress control element remains accessible and does not obstruct cable insertion.
3Stability of the object's composition
If a rigid outer insulator is used to support the termination, then structural stability is provided, but the length of the termination increases
Solution Approach 1:
The invention replaces the traditional rigid outer insulator with a flexible insulator housing that can be made of elastomeric material. This flexible housing provides sufficient structural stability to support the termination components while allowing for a more compact design with reduced length compared to rigid insulator solutions.
4Reliability
If a joint body is added to connect the cable, then connection reliability is improved, but the length of the termination increases and field testing is required
Solution Approach 1:
The invention merges the joint body function with the insulator housing into a single integrated structure. The insulator housing itself serves as the joint body that connects the cable termination, eliminating the need for a separate joint body component. This integration maintains connection reliability while reducing the overall termination length and eliminating the need for separate field testing of the joint body.
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
The solution enables fast, reliable installation of high voltage cable fittings with reduced length requirements and eliminates the need for field testing, ensuring electrical safety and efficiency.
Implementation Method 1
an insulating filling, filling the space between the connecting element and the outer insulator
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
A cable fitting comprises an outer insulator (1) of tubular shape, a sliding contact (2), a terminal (3) and a preinstalled connecting element (4). The connecting element comprises a conductor (40) which is connected to the sliding contact (2) and which connects the terminal (3) of the cable fitting with the sliding contact (2). The sliding contact (2) is suitable to be connected to a cable conductor (131) of a high voltage cable (13). An insulating filling (5) fills the space between the connecting element (4) and the outer insulator (1) up to a filling level (50). The cable fitting comprises a preinstalled joint body (6). The joint body comprises a central electrode (61) surrounding the sliding contact (2) and a lower electrode (62), preferably in the shape of a deflector embedded in the joint body insulator (60) and opening towards the sliding contact (2), arranged at least partially below the central electrode (61). Further, the joint body comprises a cover (8) which extends at least from the height of the highest point of the lower electrode (62) up into the outer insulator (1). A geometric field control (7) comprises at least one inner electrode (70) and at least one outer electrode (71). All outer electrodes (71) are arranged below and outside the outer insulator (1) while a part of the joint body (6) is arranged inside the outer insulator (1).