Encapsulated Converter Cell Module for HVDC Valves

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Solution Overview

Problem

Current power converter systems for HVDC and FACTS are costly and complex to install and maintain, with indoor installations requiring extensive insulation and environmental control, and outdoor systems face challenges in insulation and reliability due to exposure to harsh conditions.

Innovation Solution

A converter cell module with an enclosure filled with insulation fluid, containing an electrical energy storage medium and switching module, providing electrical insulation up to overvoltage levels, allowing for modular design and outdoor installation, reducing the need for extensive insulation and enabling easier maintenance by containing potential issues within the module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If indoor air insulation is used for converter stations, then electrical insulation is provided, but installation cost and complexity increase significantly

Engineering Contradiction:
Improveelectrical insulationVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The converter station is divided into individual converter cell modules, each with its own enclosure and insulation fluid. This segmentation allows each module to be independently insulated rather than requiring the entire indoor space to be insulated, reducing overall complexity while maintaining electrical insulation reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An insulation fluid is introduced as an intermediary medium within each converter cell module's enclosure. This fluid provides the necessary electrical insulation properties locally within each module, replacing the need for large-scale air insulation in indoor installations and simplifying the overall system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If converter valves are placed in insulating fluid containers, then electrical insulation is improved, but installation and maintenance complexity increases

Engineering Contradiction:
Improveelectrical insulationVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The converter valve is segmented into multiple independent converter cell modules, each containing its own insulation fluid and electrical components. This segmentation allows individual modules to be maintained or replaced without affecting other modules, significantly easing maintenance complexity while preserving the electrical insulation benefits of using insulating fluid.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If modular converter cell modules are used, then ease of installation and maintenance is improved, but individual module insulation capability must be sufficient

Engineering Contradiction:
Improveease of installationVSAvoidinsulation capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Each modular converter cell module incorporates an insulation fluid as an intermediary medium within its enclosure, providing sufficient electrical insulation capability at the module level. This allows modules to be easily installed and maintained independently while each module maintains adequate insulation performance for its operating conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design reduces installation and maintenance costs, enhances reliability by containing malfunctions, and allows for outdoor operation without the need for controlled environments, while minimizing environmental impact and downtime due to the modular nature of the converter cell modules.

Implementation Method 1

The insulation fluid is configured to provide electrical insulation within the enclosure up to an overvoltage of the converter cell module

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP4106504A1Encapsulated converter cell module
Publication Date: 2022.12.21 HITACHI ENERGY LTD
  • EP4106504A1 patent drawingFigure 1a
  • EP4106504A1 patent drawingFigure 1b
  • EP4106504A1 patent drawingFigure 2

AI summary

A converter cell module for a power converter valve of a High Voltage Direct Current, HVDC, transmission system or a Flexible Alternating Current Transmission System, FACTS, is provided. The power converter valve includes a plurality of converter cell modules electrically connected to each other. The converter cell module comprises an enclosure at least partially filled with an insulation fluid, an electrical energy storage medium for storing energy associated with the converter cell module, connectors arranged through the enclosure and configured for electrical connection of electrical terminals of the converter cell module to at least another converter cell module of the valve, and a switching module arranged to connect the electrical energy storage medium to the electrical terminals. At least the switching module is arranged within the enclosure. Further, the insulation fluid are configured to provide electrical insulation within the enclosure up to an overvoltage of the converter cell module, wherein the overvoltage is higher than an operating voltage of the converter cell module and lower than a voltage across the power converter valve.