Phase-Rotating Transformer for Live Lateral Load Rebalancing

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Solution Overview

Problem

Current methods for load balancing in three-phase power grids require manual intervention, leading to costly and disruptive outages when re-balancing single-phase laterals, and fail to address dynamic changes in power allocation due to distributed generation and faults, which can result in inefficient capacity utilization and reduced uptime for critical loads.

Innovation Solution

A system utilizing a phase rotating transformer with a stator and rotor, along with a rotary actuator and controller, enables the hot swapping of single-phase laterals between three-phase power lines without interrupting voltage, allowing for dynamic re-balancing and fault recovery by electromagnetically coupling the secondary coil with each primary coil, facilitating rapid phase changes across +/- 120 degrees.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual re-balancing is performed by line crew, then load distribution is corrected, but customer outage time increases and operational cost increases

Engineering Contradiction:
Improveload balancingVSAvoidcustomer outage time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical switching operations with an automated electronic control system. The phase switching device automatically detects phase imbalances and executes phase swaps without requiring line crew physical intervention, thereby eliminating customer outages while maintaining load balancing effectiveness.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-service load balancing by automatically monitoring phase loads and executing corrective phase switching when imbalances are detected. The controller autonomously manages the phase switching device to re-balance loads without external human intervention, preventing outages and reducing operational costs.

Inventive Principle:
Principle #25Self-service

2Reliability

If manual re-balancing is performed, then phase loading is corrected, but operational complexity increases

Engineering Contradiction:
Improveload balancingVSAvoidmanual operation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex manual coordination and communication protocols with a simplified electronic control architecture. The controller automatically monitors phase loads and commands the phase switching device, eliminating the need for manual dispatch, safety procedures, and coordination while maintaining load balancing functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Power

If three-phase trunk capacity is upgraded to prevent manual re-balancing, then load capacity increases, but capital cost increases

Engineering Contradiction:
Improvetrunk capacityVSAvoidcapital cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent implements dynamic phase switching capability that allows the system to adaptively redistribute loads among phases in real-time. This dynamic reconfiguration enables the existing three-phase trunk to handle variable loads more effectively without requiring capacity upgrades, avoiding significant capital expenditures.

Inventive Principle:
Principle #15Dynamics

4Reliability

If single-phase laterals are manually swapped during faults, then critical load uptime is maintained, but response time decreases

Engineering Contradiction:
Improvecritical load uptimeVSAvoidfault response time
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The system continuously monitors phase loads and fault conditions, providing real-time feedback to the controller. When faults or imbalances are detected, the controller immediately commands the phase switching device to reconfigure connections, enabling rapid automatic response that maintains critical load uptime without waiting for manual fault detection and assessment.

Inventive Principle:
Principle #23Feedback

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 continuous power supply during phase changes, maintains balanced load distribution, and increases uptime by allowing hot swapping of single-phase laterals, reducing capital and maintenance costs while preventing load drops and maintaining a smooth sinusoidal voltage shape.

Implementation Method 1

A system utilizing a phase rotating transformer with a stator and rotor, along with a rotary actuator and controller, enables the hot swapping of single-phase laterals between three-phase power lines without interrupting voltage, allowing for dynamic re-balancing and fault recovery by electromagnetically coupling the secondary coil with each primary coil

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP4147319B1Load re-balancing on a multi-phase power system
Publication Date: 2024.12.11 AMERICAN SUPERCONDUCTOR CORP
  • EP4147319B1 patent drawingFigure 1
  • EP4147319B1 patent drawingFigure 2A
  • EP4147319B1 patent drawingFigure 2B

AI summary

A system for load balancing on a multi-phase power line connected to a single phase lateral power line, includes a contactor configured to selectively connect each phase of the multi-phase power line to the single phase lateral power line. There is a phase change device connected in parallel with the contactor and a controller. During the phase change state, the controller connects the input of the phase change device to the multi-phase power line and connects the output of the phase change device the single phase lateral power line. The controller causes the phase change device to output a voltage to the single phase lateral line initially aligned with the first phase and then rotated to align with the second phase and causes the contactor changes connection to the second phase of the multi-phase power line and disconnect the phase change device from the power lines.