Modular Converter Earth Potential Contact System

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Solution Overview

Problem

Existing modular multilevel power converters face challenges in ensuring reliable connection of DC voltage sources to earth potential due to the risk of interruption when multiple sliding contacts fail, which complicates maintenance and safety.

Innovation Solution

A potential compensation system with electrically conductive contact elements that can transition between separated and connected positions, utilizing shielding and conductive ropes to maintain earth connection even if individual pole contacts fail, and a common drive mechanism for synchronized movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high number of sliding contacts connected in series is used to connect DC sources to earth potential, then the connection coverage is improved, but the reliability deteriorates due to interruption risk when contacts fail

Engineering Contradiction:
Improveconnection reliabilityVSAvoidnumber of contacts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system divides the converter station into multiple converter modules, each with its own pole contacts. The contacting element is segmented to contact pole contacts from different DC voltage sources sequentially or simultaneously, allowing the system to manage complexity through modular segmentation while maintaining reliable earth potential connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contacting element acts as an intermediary between the pole contacts and earth potential. It temporarily contacts multiple pole contacts from different DC voltage sources and transfers the earth potential to all of them, eliminating the need for a complex series connection of sliding contacts while improving reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If multiple sliding contacts are used to ensure earth potential connection, then the coverage is improved, but the operational safety worsens due to potential interruption from contact failure

Engineering Contradiction:
Improveearth potential connectionVSAvoidconnection continuity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The contacting element is designed to preliminarily contact pole contacts from different DC voltage sources before maintenance work begins. By establishing earth potential connection in advance through the contacting element that can bridge multiple sources, the system ensures operational safety even if individual sliding contacts fail during maintenance.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If separate shielding and contacting elements are used, then the shielding function is improved, but the material and construction effort increases

Engineering Contradiction:
Improveelectrical shieldingVSAvoidconstruction effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the shielding function and the contacting element function into a single integrated component. The contacting element itself is designed to provide electrical shielding while maintaining contact with pole contacts, eliminating the need for separate shielding structures and reducing material and construction effort.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The contacting element is designed with multi-functionality, serving both as the electrical contact component and as the shielding element. This universal component performs multiple functions (contacting and shielding) simultaneously, simplifying the overall structure and reducing construction complexity while maintaining reliable electrical shielding.

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

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

Enhances the reliability and safety of connecting multiple DC voltage sources to earth potential by reducing the risk of interruption and simplifying the connection process, while minimizing material and operational costs.

Implementation Method 1

at least an electrically conductive contact element that is between a first end position in which it is electrically separated from the converter modules, and a second end position in which it can contact pole contacts from various DC voltage sources and is connectable to an earth potential

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

at least one contacting element is an electrical shielding to shield several agent modules, which can be rotated by a axis of rotation between the first end position and the second end position

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 3

the axis of rotation of the shield is a longitudinal axis of the shielding tube

Methodology Applied
Scientific EffectMechanical Rotation:

Implementation Method 4

at least one contacting element is an electrically conductive contact rope, for example a copper rope, which can be laid in the first end position on an electrically insulating, which can be managed on an electrically insulating, which can be operated via pole contacts of various DC

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 5

the contact rope is run over a second rope drum and both rope drums are installed on a manually, mechanical or electrically exhaustable drive shaft

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3788707B1Potential equalisation system for a modular multilevel converter
Publication Date: 2022.10.12 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3788707B1 patent drawingFigure 1
  • EP3788707B1 patent drawingFigure 2
  • EP3788707B1 patent drawingFigure 3~4

AI summary

The invention relates to a potential equalisation system for a modular multi-level converter (1) having a plurality of converter modules (3) which each have a direct current source (13). The potential equalisation system comprises pole contacts (15), which are each electrically connected to one pole of a direct current source (13), and at least one electrically conductive contacting element (17), which can be moved between a first end position in which said contacting element is electrically isolated from the converter modules (3) and a second end position in which said contacting element contacts pole contacts (15) of different direct current sources (13) and can be placed onto an earth potential.