Mineral Insulated Cable Splice Compaction for High Voltage
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Solution Overview
Problem
Conventional mineral insulated (MI) cable splice designs are not suitable for high voltages above 1000 volts, 1500 volts, or 2000 volts and fail at elevated temperatures, requiring improved compaction of mineral insulation to match the level in the insulated conductor, and need higher bending and tensile strengths to withstand subsurface conditions.
Innovation Solution
A system and method for coupling insulated conductors using a box with plungers to compact electrically insulating powder material around the exposed cores, forming a cylindrical shape with a sleeve to match the conductor diameter, enhancing compaction and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MI cable splice designs are used, then the splice structure is simple, but the splice fails at high voltages above 1000 volts and elevated temperatures
Solution Approach 1:
The patent applies preliminary action by pre-forming the insulating powder into a compacted cylindrical shape within the splice housing before final assembly. This pre-compaction ensures that when the splice is assembled and subjected to high voltage and temperature conditions, the insulating material is already in its optimal dense state, preventing electrical breakdown and ensuring reliable operation at voltages above 1000 volts and elevated temperatures.
Solution Approach 2:
The patent applies parameter changes by transforming the insulating powder material through compaction to achieve a specific density and physical state. The compaction process changes the physical parameters of the insulating material (density, porosity, mechanical strength) to match or exceed the compaction level of the insulated conductor itself, enabling the splice to withstand high voltage stress and elevated temperature conditions that would cause conventional splices to fail.
2Reliability
If conventional splice compaction methods are used, then the manufacturing process is simple, but the compaction level does not match the insulated conductor, leading to electrical breakdown
Solution Approach 1:
The patent applies segmentation by dividing the compaction process into distinct stages: first, the insulating powder is compacted into a cylindrical shape within a separate housing; second, this pre-compacted cylinder is inserted into the splice assembly; third, final compaction is applied to match the conductor's compaction level. This segmented approach ensures the insulating material achieves the required density for high voltage reliability while maintaining manufacturing feasibility through modular processing steps.
Solution Approach 2:
The patent applies pneumatic and hydraulic principles by using fluid pressure (pneumatic or hydraulic systems) to compact the insulating powder material. This method delivers controlled, uniform compaction force throughout the insulating material, achieving the necessary density and physical properties to match the insulated conductor's compaction level, thereby preventing electrical breakdown at high voltages while maintaining ease of manufacture through automated fluid pressure application.
3Manufacturing precision
If higher compaction is applied to match insulated conductor level, then electrical performance improves, but manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent applies the nested doll principle by placing the pre-compacted insulating powder cylinder inside a housing that is itself inserted into the splice assembly, which contains the conductor and other components. This nested structure allows the compaction process to be performed on the insulating material in isolation within its own housing, achieving uniform high compaction without requiring complex equipment to simultaneously manage multiple components. The nested arrangement simplifies the overall manufacturing process while ensuring the insulating material reaches the required compaction uniformity for electrical performance.
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 splices that operate reliably at high voltages and temperatures, reducing electric field intensities and leakage currents, and increasing the margin between operating voltage and electrical breakdown, thus extending the operational range of MI cable splices.
Implementation Method 1
applying a force to the first plunger to compact the powder material, wherein the powder material is compacted into compacted powder material that at least partially surrounds a part of the exposed portions of the cores
Data Source
AI summary
An apparatus and method for coupling ends of two insulated conductors includes coupling a core of a first insulated conductor to a core of a second insulated conductor. Exposed portions of the cores are located inside a box. Electrically insulating powder material is placed into the box and a force is applied to first and second plungers to compact the powder material. Additional electrically insulating powder material may placed into the box and a subsequent force applied to compact the powder material into compacted powder material that surrounds the exposed portions of the cores. The compacted powder material is formed into a substantially cylindrical shape. A sleeve is placed over the compacted powder material and coupled to the jackets of the insulated conductors.