Converter Submodule Health Monitoring via Group Deviation Analysis

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Solution Overview

Problem

Existing condition monitoring methods for electronic components in electrical power systems, such as MMCs and E-STATCOMs, require additional hardware and are not sufficiently accurate without it, especially for assessing health status based on temperature-dependent characteristics.

Innovation Solution

A computer-implemented method that determines the health status of electrical components by calculating deviations in temperature-dependent electrical characteristics using existing control and monitoring system data, without the need for additional sensors, by grouping components with similar circuit topologies and assuming equal thermal responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional monitoring methods (thermal imaging, ultrasonic detection) are used, then equipment safety can be monitored, but the methods are cumbersome, require specialized operations, and cannot provide real-time continuous monitoring

Engineering Contradiction:
Improveequipment safety monitoringVSAvoidmonitoring method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical monitoring methods (thermal imaging cameras, ultrasonic detectors requiring specialized operations) with an electrical measurement system using voltage detectors and current transformers. This substitution eliminates the need for cumbersome specialized equipment and operations, enabling simple, real-time continuous monitoring through standard electrical parameters measurement.

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

Solution Approach 2:

The monitoring system uses the electrical components' own operating parameters (voltage and current) to detect their health status. The voltage detector monitors insulation resistance by measuring leakage current, and the current transformer monitors winding temperature through current measurement. This self-diagnosis approach eliminates the need for external specialized monitoring equipment and manual inspections.

Inventive Principle:
Principle #25Self-service

2Reliability

If traditional monitoring methods are used, then equipment safety can be monitored, but real-time continuous monitoring cannot be achieved

Engineering Contradiction:
Improveequipment safety monitoringVSAvoidmonitoring time response
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements continuous real-time monitoring through permanent installation of voltage detectors and current transformers on the electrical components. These devices continuously measure voltage, current, and derived parameters (insulation resistance, temperature) without interruption, providing uninterrupted safety monitoring that enables immediate detection of developing faults and timely preventive maintenance.

Inventive Principle:
Principle #20Continuity of useful action

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

Accurately monitors the health of electrical components in power systems without additional hardware, enabling timely maintenance by identifying deviations from group values based on existing system data, thus reducing costs and improving maintenance efficiency.

Implementation Method 1

a voltage detector configured to measure a voltage across the electric motor winding and detect an insulation resistance of the electric motor winding based on the measured voltage

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

a current transformer configured to measure a current through the electric motor winding and detect a temperature of the electric motor winding based on the measured current

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP4487437B1Condition monitoring of electronic components in electrical power systems
Publication Date: 2026.05.06 HITACHI ENERGY LTD
  • EP4487437B1 patent drawingFigure 1~2
  • EP4487437B1 patent drawingFigure 3
  • EP4487437B1 patent drawingFigure 4

AI summary

There is disclosed herein a computer-implemented method for monitoring a converter comprising a plurality of series-connected submodules or an energy storage system (ESS) comprising a plurality of series-connected energy storage units (ESUs). Each submodule or ESU has electrical components arranged in a same circuit topology. The method comprises determining, for each electrical component in a group, a component value for an electrical characteristic, wherein the group comprises a corresponding electrical component from each submodule/ESU, in the plurality of submodules/ESUs, having a same position in the circuit topology of their respective submodule/ESU. The method further comprises determining, for the group of electrical components, a group value for the electrical characteristic. The method then comprises determining a deviation of the component value from the group value, for each electrical component in the group, and determining a health status for an electrical component of the group based on the determined deviation for the electrical component.