RF Current Transformer Monitoring for Generator Arcing Detection

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Solution Overview

Problem

Regularly scheduled maintenance of electrical generators is costly and risky, as it does not prioritize maintenance based on device performance or health indicators, leading to unnecessary maintenance of healthy generators and delayed servicing of unhealthy ones, and can result in catastrophic flashover events due to arcing issues in collector assemblies.

Innovation Solution

The system detects arcing events in electrical systems by measuring RF signals using radio frequency current transformers, allowing for health-based maintenance and real-time monitoring of collector assemblies without disrupting the equipment, enabling the adjustment of operational parameters to prevent arcing and predict maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If regularly scheduled inspection and maintenance is performed, then the risk of flashover is minimized and generator integrity is verified, but maintenance costs increase and operational downtime is required

Engineering Contradiction:
Improvegenerator integrityVSAvoidoperational downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces mechanical inspection methods with electromagnetic field-based detection. RF current transformers and partial discharge detectors use electromagnetic principles to monitor collector ring and brush health without physical contact, eliminating the need for shutdowns and manual inspections while maintaining reliability

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

Solution Approach 2:

The monitoring system enables the generator to self-diagnose its own health status through continuous RF and partial discharge monitoring. The system automatically detects arcing, measures brush wear, and identifies collector ring issues without external intervention, allowing operation until actual maintenance is needed rather than following fixed schedules

Inventive Principle:
Principle #25Self-service

2Ease of operation

If strictly schedule-based maintenance is used, then maintenance timing is simplified, but healthy generators receive unnecessary maintenance while unhealthy machines are delayed in receiving servicing

Engineering Contradiction:
Improvemaintenance schedulingVSAvoidmaintenance prioritization
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system continuously monitors RF signal levels, partial discharge activity, and brush/collector ring condition, providing real-time feedback on actual equipment health. This feedback loop enables dynamic adjustment of maintenance schedules based on measured conditions rather than fixed timelines, ensuring maintenance is performed when actually needed

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The maintenance strategy transitions from static, predetermined schedules to dynamic, condition-based scheduling. The system adapts maintenance timing based on real-time measurements of arcing, brush wear, and collector ring condition, allowing flexible adjustment of maintenance intervals to match actual equipment needs

Inventive Principle:
Principle #15Dynamics

3Productivity

If generator maintenance is performed while the generator operates, then operational downtime is reduced, but the complexity and safety risks of maintenance increase

Engineering Contradiction:
Improveoperational continuityVSAvoidmaintenance complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical inspection procedures with non-contact electromagnetic monitoring. RF current transformers and partial discharge detectors monitor equipment health through electromagnetic fields without requiring disassembly or physical access to rotating components, maintaining safety while enabling continuous operation

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

Solution Approach 2:

The system introduces intermediary sensing devices (RF current transformers, partial discharge detectors) that mediate between the operating generator and the monitoring system. These intermediaries capture health information without requiring direct contact with rotating parts, enabling safe remote monitoring during operation

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 approach reduces maintenance costs and safety risks by enabling health-based maintenance, minimizing downtime, and preventing flashover events by detecting arcing issues before they cause significant damage, while allowing for real-time tuning of operational parameters to maintain system performance.

Implementation Method 1

measuring RF signals using radio frequency current transformers

Methodology Applied
Scientific EffectRadio frequency signal generation:

Implementation Method 2

arcing events may occur... a brush and collector ring may arc

Methodology Applied
Scientific EffectArcing: Electric Arc

Implementation Method 3

collecting partial discharge data from a first electrical device

Methodology Applied
Scientific EffectPartial discharge:

Data Source

PatentEP2579057B1Systems and methods for monitoring the health of an electrical system
Publication Date: 2018.12.12 GENERAL ELECTRIC CO
  • EP2579057B1 patent drawingFigure 1
  • EP2579057B1 patent drawingFigure 2
  • EP2579057B1 patent drawingFigure 3

AI summary

The subject matter herein generally relates to electrical generators and motors, and more specifically, to electrical turbo-generators. In an embodiment, an electrical system includes a circuit. The circuit includes one or more rotating power delivery assemblies comprising a plurality of sliding surfaces that deliver power to a rotating load. The circuit also includes one or more radio frequency current transformers (RFCTs) that measure radio frequency (RF) signals corresponding to arcing events in the one or more rotating power delivery assemblies. The electrical system also includes a processor that receives the measurements from the one or more RFCTs and determines a health value of the circuit based, at least in part, on the received measurements.