Subsea Feeder Unit Balancing Three-Phase Power for Pipeline Heating
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Solution Overview
Problem
Conventional direct electric heating systems for subsea pipelines are limited by short heating distances, lack of control, significant energy losses, and high costs due to the use of single-phase power transmission and expensive subsea cables, which restrict their effectiveness in deep water hydrocarbon transportation.
Innovation Solution
A direct electric heating system utilizing a subsea feeder unit that connects pipeline sections to a three-phase power source, balancing loads with a current balancing reactor and compensating reactive power, allowing for longer heating distances and reduced energy losses through efficient three-phase AC power transmission and independent control of heating sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-phase power transmission is used to heat subsea pipelines, then the heating system can be implemented with simple connections, but the heating distance is limited and energy losses are significant
Solution Approach 1:
The patent changes the electrical system parameters from single-phase to three-phase power transmission. This parameter change enables longer heating distances by distributing the load across three phases, reducing current per phase, and minimizing energy losses in the subsea cable, thereby resolving the contradiction between connection simplicity and heating distance limitation.
2Device complexity
If single-phase power transmission is used, then the system structure is simple, but energy losses in the cable are significant
Solution Approach 1:
The patent transitions from single-phase to three-phase power transmission, changing the electrical system parameters. This enables more efficient power delivery over long distances by reducing current magnitude for the same power level, thereby significantly reducing I²R losses in the subsea cable while maintaining acceptable system complexity through standardized three-phase equipment.
3Productivity
If conventional heating systems are used, then short pipeline sections can be heated, but longer pipeline sections cannot be effectively heated
Solution Approach 1:
The patent implements three-phase power transmission which fundamentally changes the power delivery capability. This enables effective heating of longer pipeline sections by providing sufficient power over extended distances through balanced three-phase currents, directly resolving the limitation on pipeline section length while maintaining heating productivity.
4Length of stationary object
If three-phase power transmission with load balancing is implemented, then heating distance and efficiency are improved, but system complexity increases
Solution Approach 1:
The patent segments the heating system into multiple independent heating zones, each served by three-phase power transmission. This segmentation allows each zone to be controlled independently with load balancing, enabling long-distance heating while managing system complexity through modular design and standardized three-phase components.
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
Enables efficient and cost-effective heating of longer subsea pipeline sections with reduced energy losses and lower cable costs, allowing for independent control and fault-tolerant operation by balancing loads and compensating reactive power, thus improving the reliability and efficiency of subsea hydrocarbon transportation.
Implementation Method 1
A 50/60 Hz AC current is passed through the cable and the pipeline, and the pipeline is heated due to its electric resistance
Data Source
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AI summary
A direct electric heating system for heating a subsea pipeline is provided. The direct electric heating system has a subsea feeder unit which is adapted to be installed subsea. The subsea feeder unit comprises electric connections for coupling the subsea feeder unit to a three phase power source for receiving three phase electric power. The subsea feeder unit includes a balancing unit which is configured to balance the load on the three phases of the three phase power source.