Semiconductive Cable Tape Pre-Extraction for Dielectric Reliability
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Solution Overview
Problem
Existing methods for manufacturing medium- and high-voltage electric cables using cross-linked polyethylene insulating systems face issues with the migration of undesirable chemical species, particularly water, which degrade dielectric performance and mechanical properties, leading to reliability concerns in energy transmission networks.
Innovation Solution
A method involving a pre-extraction step to remove undesirable chemical species, such as water, from the tape material before application around the cable core, using heating and gaseous flows to maintain dielectric performance and mechanical integrity of the insulating system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tape material is applied around the cable core without pre-extraction, then the manufacturing process is simple and fast, but undesirable chemical species migrate into the insulating system and degrade dielectric performance
Solution Approach 1:
The patent applies a pre-extraction treatment to the tape material before it is wound around the cable core. This preliminary action removes undesirable chemical species (particularly water) from the tape in advance, preventing their migration into the insulating system during cable operation. The extraction is performed by heating the tape to a temperature between 50°C and 100°C in a controlled atmosphere, which eliminates harmful substances before they can cause dielectric degradation.
Solution Approach 2:
The patent converts the potentially harmful effect of heating (which could degrade the tape or insulating system) into a beneficial extraction process. By carefully controlling the heating temperature and atmosphere, the process removes undesirable chemical species from the tape without damaging the materials. The heat that could potentially cause degradation is instead used to drive out moisture and other harmful substances, improving the overall reliability of the cable.
2Reliability
If pre-extraction step is added to remove chemical species from tape, then dielectric performance is maintained, but manufacturing time and energy consumption increase
Solution Approach 1:
The patent optimizes the extraction parameters to achieve effective removal of chemical species within a controlled time frame. The heating temperature is maintained between 50°C and 100°C, and the extraction atmosphere is controlled to facilitate rapid moisture removal. These parameter optimizations ensure that the extraction process is sufficiently fast for industrial production while still achieving the desired reduction in harmful substances.
Solution Approach 2:
The extraction process is designed to be continuous rather than batch-based, where the tape undergoes continuous heating and extraction as it is prepared for winding. This continuous action eliminates idle time between extraction and application, maintaining production flow and minimizing the overall impact on manufacturing cycle time.
3Duration of action of stationary object
If tape contains moisture and chemical species, then the manufacturing process is simpler, but cable lifespan is reduced due to degradation in humid environments
Solution Approach 1:
The extraction process is conducted in a controlled inert atmosphere that prevents re-absorption of moisture during the extraction operation. This controlled environment ensures that once chemical species are removed from the tape, they cannot be readily re-absorbed, thereby maintaining the improved quality of the tape throughout the manufacturing process and extending cable lifespan.
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 method effectively limits the loss of dielectric performance and extends the lifespan of electric cables by preventing the migration of undesirable species, particularly in humid environments, thereby enhancing the reliability and durability of the cables.
Implementation Method 1
A method involving a pre-extraction step to remove undesirable chemical species, such as water, from the tape material before application around the cable core, using heating and gaseous flows
Implementation Method 2
using heating and gaseous flows to maintain dielectric performance and mechanical integrity of the insulating system
Data Source
AI summary
The invention relates to a method for manufacturing a medium- or high-voltage electric cable, of the type comprising:a core formed of an elongate electrically conductive element and of an insulating system comprising at least one layer comprising at least one cross-linked polyethylene, said at least one layer being arranged coaxially around the elongate electrically conductive element, anda tape enveloping the corethe tape being formed of a semiconductor polymer material.,characterised in that the method comprises at least one step of extracting at least one chemical species from the tape, said chemical species being a chemical species able to reach the insulating system by migration from the tape and to decrease the dielectric performance of the insulating system.