Pipeline Heating Power Supply with Load Balancing and Power Factor Control
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Solution Overview
Problem
Existing power supply systems for subsea pipeline electrical heating face challenges in efficiently converting three-phase power to single-phase power and maintaining optimal power factor and load balance, leading to issues with transformer safety and efficiency.
Innovation Solution
A power supply arrangement featuring a three-phase transformer with on-load tap changers, symmetrization and compensation units, including capacitors and inductors, which can be automatically controlled to support single-phase loads and maintain optimal power factor and load balance, allowing for real-time optimization and reduced negative sequence currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If three-phase power is converted to single-phase power for pipeline heating, then the heating function is achieved, but transformer safety and efficiency deteriorate due to unbalanced loads and poor power factor
Solution Approach 1:
The patent introduces a three-phase transformer with specific winding connections (e.g., delta-wye or delta-delta with neutral) as an intermediary device between the three-phase power source and single-phase heating load. This transformer configuration allows single-phase power delivery while maintaining three-phase balance on the primary side, preventing transformer overheating and ensuring safe operation.
Solution Approach 2:
The patent employs power factor correction capacitors and adjustable transformer tap changers to dynamically change electrical parameters (power factor, voltage levels) in response to load conditions. This maintains optimal transformer efficiency and safety while delivering required heating power, resolving the contradiction between heating productivity and transformer reliability.
2Productivity
If three-phase power is converted to single-phase power for pipeline heating, then the heating function is achieved, but energy efficiency deteriorates due to poor power factor
Solution Approach 1:
The patent introduces power factor correction capacitors as intermediary reactive power sources that compensate for the inductive reactive power consumed by the heating load. These capacitors are connected in parallel with the load or on the transformer secondary side, providing local reactive power and improving overall system power factor to reduce energy losses.
Solution Approach 2:
The patent incorporates power factor monitoring and automatic capacitor switching control that provides feedback on system power factor conditions. Based on measured power factor values, the control system automatically switches capacitor banks in or out to maintain optimal power factor, minimizing energy losses while supporting continuous heating operation.
3Productivity
If three-phase power is converted to single-phase power for pipeline heating, then the heating function is achieved, but system versatility deteriorates due to limited operational flexibility
Solution Approach 1:
The patent employs on-load tap changers (OLTC) on the transformer that allow continuous or stepped adjustment of the transformer turns ratio while the heating system remains operational. This dynamic adjustment capability enables flexible control of secondary voltage and delivered power levels, providing operational versatility for different heating requirements without system shutdown.
Solution Approach 2:
The patent incorporates periodic or demand-based switching of capacitor banks and tap positions based on monitored load conditions and power factor requirements. This periodic adjustment provides adaptive operational flexibility, optimizing system performance for varying heating demands while maintaining continuous heating operation.
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
This solution enables efficient and safe operation of direct electrical heating systems by maintaining a near unity power factor and minimizing negative sequence currents, allowing for continuous operation with minimal system stoppages and reduced fire risks.
Implementation Method 1
a three phase transformer adapted to support a single phase load connected between a first phase and a second phase of the transformer
Implementation Method 2
a compensation unit comprising a second capacitor means connected between the first phase and the second phase of the transformer
Implementation Method 3
a symmetrization unit comprising a first capacitor means connected between the first phase and a third phase of the transformer and an inductor means connected between the second phase and the third phase of said transformer
Implementation Method 4
direct electrical heating (DEH) method is used for heating of the pipeline by forcing a high electric current through the pipeline itself
Data Source
AI summary
In a power supply arrangement for supplying electrical power to the pipeline, the power supply arrangement for direct electrical heating of a pipeline system has basically a three phase transformer, a symmetrization unit, and a compensation unit. The three phase transformer is adapted to support a single phase load connected between a first and a second phase of the transformer. The transformer has at least one first tap changer at a high voltage side of the transformer. The symmetrization unit has a first capacitor connected between the first phase and a third phase of the transformer and an inductor connected between the second phase and the third phase of the transformer. The compensation unit has a second capacitor connected between the first phase and the second phase of the transformer. The first tap changer, the first capacitor, the second capacitor and the inductor are adapted to be varied on-load.