Power Cable Insulation Heating Assembly Pressure Control
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Solution Overview
Problem
The existing devices for restoring power cable insulation systems suffer from deformation due to pressure differences, leading to reduced performance, as the insulation system is pushed laterally outwards when heated under pressure.
Innovation Solution
A heating assembly with a central pressurization and heating structure, and a pressure compensator system comprising lateral structures made of low conductivity materials, which provides counterpressure and minimizes heating of the lateral structures, preventing deformation by inducing minimal current and maintaining pressure equilibrium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulation system is heated under pressure inside the central heating chamber, then the curing process is effective and the insulation system is restored, but the insulation system is pushed laterally outwards causing deformation
Solution Approach 1:
The patent introduces a pressure compensator system with lateral structures that apply counterpressure to the insulation system from the lateral channels. This counterpressure balances the internal pressure in the central heating chamber, preventing the insulation system from being pushed laterally outwards while maintaining the pressure needed for effective curing.
2Productivity
If high frequency heating coils are arranged around the lateral structures for inner heating, then the curing process is accelerated, but the lateral structures may be heated to temperatures causing material deformation
Solution Approach 1:
The patent applies local quality by using materials with different electrical conductivities in different parts of the lateral structures. The axially extending sections use low conductivity materials (at most 1000 S/m) to minimize induced current and heating, while other sections may use different materials optimized for their specific functions. This localized material selection prevents excessive heating of critical sections while allowing efficient heating where needed.
3Strength
If the lateral structures are made of highly conductive materials, then the structural strength is sufficient, but large currents are induced causing excessive heating and potential deformation
Solution Approach 1:
The patent employs composite materials in the lateral structures, combining materials with different properties. The axially extending sections use low conductivity materials (at most 1000 S/m) to minimize induced current, while maintaining sufficient mechanical strength through composite construction. This allows the structure to withstand mechanical loads while minimizing electromagnetic heating effects.
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 effectively prevents deformation of the insulation system, ensuring consistent performance by maintaining pressure equilibrium and minimizing heat-induced deformation, thus maintaining the integrity of the insulation system during the curing process.
Implementation Method 1
the central pressurisation and heating structure is configured to be pressurised to obtain a first pressure higher than atmospheric pressure inside the central heating chamber
Implementation Method 2
the first lateral structure is configured to be pressurised to obtain a second pressure higher than atmospheric pressure in the first lateral channel, and wherein the second lateral structure is configured to be pressurised to obtain a third pressure higher than atmospheric pressure in the second lateral channel
Implementation Method 3
each of the first lateral structure and the second lateral structure has an at least 20 cm long axially extending section which is primarily made of material at most having a conductivity of the order of 1000 S/m at 20°C
Implementation Method 4
a small current is induced in these structures when high frequency heating coils are arranged around the structures for heating a conductor of a power cable
Implementation Method 5
heating assembly configured to receive a power cable joint of a power cable for curing an uncured insulation system layer of the power cable joint
Data Source
Figure 1~2
Figure 3
AI summary
A heating assembly (1) configured to receive a power cable (9) for restoring an insulation system of the power cable, the heating assembly (1) comprising: a central pressurisation and heating structure (3), and a first and second lateral structure (5, 7) provided at a respective axial end of the central pressurisation and heating structure (3), the first and second lateral structure (5, 7) each having at least a 20 cm long axially extending section primarily made of a material at most having a conductivity of the order of 1000 S/m at 20°C.