Fiber Optic Asset Sensing for EMI-Resistant Grid Condition Detection

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Solution Overview

Problem

Existing methods for monitoring the condition and predicting the health of electrical device assets, such as transformers and voltage regulators, in power grids lack effective solutions for detecting subtle changes and predicting maintenance needs, especially in harsh environments with significant electromagnetic interference.

Innovation Solution

A sensor system utilizing optical sensors embedded in optical fibers to detect vibrations and temperature changes within electrical devices, generating time domain signals that are analyzed to identify eigenfrequencies and detect conditions such as corrosion, oil degradation, and mechanical impacts, allowing for early detection of anomalies and scheduling of maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional electrical sensors are used to monitor electrical device assets, then the system can detect electrical parameters, but the sensors are affected by electrical noise and cannot operate reliably in harsh electromagnetic environments

Engineering Contradiction:
Improvesensor reliability in harsh environmentsVSAvoidelectromagnetic interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces traditional electrical sensors with optical fiber sensors that use light instead of electrical signals. The optical sensors are immune to electromagnetic interference, allowing reliable operation in harsh environments. The system uses optical time domain reflectometry (OTDR) to detect vibrations and acoustic emissions from electrical equipment without being affected by electrical noise.

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

Solution Approach 2:

The patent introduces optical fiber as an intermediary medium between the electrical device and the detection system. The optical fiber acts as a sensor that converts mechanical vibrations and acoustic emissions into optical signals, which are then analyzed to detect equipment conditions. This intermediary approach isolates the detection system from electromagnetic interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If long data acquisition periods are used to analyze device conditions, then measurement precision improves, but the response time for detecting critical conditions deteriorates

Engineering Contradiction:
Improvecondition detection accuracyVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the data acquisition process into multiple time windows of different lengths. Short time windows are used for rapid detection of critical conditions and transient events, while long time windows provide detailed spectral analysis for precise condition assessment. This multi-scale segmentation allows the system to simultaneously achieve fast response and high measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically adjusts the data acquisition window length based on the detected signal characteristics and criticality of the condition. When transient or critical events are detected, the system switches to shorter windows for rapid response. For steady-state conditions, longer windows are used to improve measurement precision. This dynamic adaptation optimizes both response time and accuracy.

Inventive Principle:
Principle #15Dynamics

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 provides accurate and timely detection of device conditions, enabling predictive maintenance and extending the lifespan of electrical assets by identifying subtle changes and anomalies in real-time, even in harsh environments with high electromagnetic interference.

Implementation Method 1

optically sensing vibrations of an electrical device using at least one optical sensor and producing a time variation in light output from the optical sensor in response to the vibration

Methodology Applied
Scientific EffectVibration sensing: Vibration

Data Source

PatentEP3812710B1Fiber optic sensing system for grid-based assets
Publication Date: 2023.11.08 PALO ALTO RESEARCH CENTER INC
  • EP3812710B1 patent drawingFigure 1
  • EP3812710B1 patent drawingFigure 2A
  • EP3812710B1 patent drawingFigure 2B

AI summary

A sensor system includes a sensor network comprising at least one optical fiber having one or more optical sensors. At least one of the optical sensors is arranged to sense vibration of an electrical device and to produce a time variation in light output in response to the vibration. A detector generates an electrical time domain signal in response to the time variation in light output. An analyzer acquires a snapshot frequency component signal which comprises one or more time varying signals of frequency components of the time domain signal over a data acquisition time period. The analyzer detects a condition of the electrical device based on the snapshot frequency component signal.