Multi-Winding Transformer Layout for Grid Power Imbalance Control

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Solution Overview

Problem

Existing power control systems for power networks are costly due to the need for dedicated high voltage transformers for Current Source Converters, which are underutilized, and lack redundancy and modularity in handling power imbalances.

Innovation Solution

A power control system with a transformer having multiple windings, integrating Voltage Source Converters, Current Source Converters, and Synchronous Condensers, sharing a single high voltage transformer to handle reactive and active power, ensuring redundancy and cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dedicated high voltage transformer is used for Current Source Converter, then the CSC can handle active power imbalance, but the system cost increases and the transformer becomes underutilized

Engineering Contradiction:
Improvepower imbalance handling capabilityVSAvoidtransformer utilization efficiency
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The high voltage transformer is designed with multiple windings that can serve different functions: the first winding connects to the AC power network, the second winding connects to the Voltage Source Converter for reactive power control, and the third winding connects to the Current Source Converter for active power control. This multi-functional design allows a single transformer to replace what would traditionally require multiple dedicated transformers, eliminating underutilization while maintaining full operational capabilities for both active and reactive power imbalance handling.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate transformers are used for VSC and CSC, then each converter has dedicated resources, but the total system cost increases

Engineering Contradiction:
Improveconverter operation reliabilityVSAvoidtotal transformer resources
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines the high voltage transformers for the Voltage Source Converter and Current Source Converter into a single shared transformer with multiple windings. The first winding serves the AC network connection, the second winding serves the VSC, and the third winding serves the CSC. This merging approach reduces the total number of high voltage transformers required while ensuring that both converters have dedicated winding connections, maintaining operational reliability without requiring separate physical transformers for each converter.

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If a single transformer is shared between VSC and CSC, then cost is reduced, but the transformer must handle multiple functions simultaneously

Engineering Contradiction:
Improvetransformer quantityVSAvoidtransformer winding configuration
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The shared high voltage transformer is segmented into multiple independent windings, each dedicated to a specific function: the first winding for AC network connection, the second winding for Voltage Source Converter connection, and the third winding for Current Source Converter connection. This segmentation allows each winding to operate independently for its designated purpose while being part of a single integrated transformer structure, managing the complexity through functional separation within a unified device.

Inventive Principle:
Principle #1Segmentation

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 system efficiently manages power imbalances by sharing transformer resources, reducing costs and enhancing redundancy, while maintaining high reliability and availability for power network stability.

Implementation Method 1

a transformer with at least three windings, in which a primary winding of the transformer is connected to an input from the power network

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4447251B1Power control system for power network
Publication Date: 2025.10.15 HITACHI ENERGY LTD
  • EP4447251B1 patent drawingFigure 1
  • EP4447251B1 patent drawingFigure 2
  • EP4447251B1 patent drawingFigure 3A~3C

AI summary

Embodiments herein provide a power control system (100) for controlling reactive power and/or active power in a power network. The power control system (100) is operatively coupled to the power network at a point of common coupling, PCC. The power control system (100) comprises a transformer (10) with at least three windings, in which a primary winding of the transformer (10) being connected to an input from the power network. The power control system (100) further comprises a voltage-source converter, VSC (20), being connected to a secondary winding of the transformer (10), wherein the VSC (20) is configured to work as a source or a sink of reactive power in the power network. The power control system (100) further comprises a Current Source Converter, CSC, (30) being connected to a tertiary winding of the transformer (10) and the CSC (30) is configured to handle power imbalance in the power network. Corresponding power compensator module is also disclosed.