Generator Seal Leakage Detection and Oil Contamination Monitoring

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Solution Overview

Problem

Gas cooled generators face issues with hydrogen leakage and contamination due to static seal leaks and shaft seal system anomalies, leading to reduced hydrogen purity and increased consumption, which existing scavenging systems often fail to adequately address.

Innovation Solution

A system comprising sensors and detectors for monitoring cooling gas flow rates, purity, and seal oil conditions, generating alarms for leaks, contamination, and shaft seal ring clearance, with a scavenging system that adjusts scavenge rates to maintain hydrogen purity, including a static seal leak detector, seal oil contamination detector, and shaft seal ring clearance detector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If scavenging levels are increased to raise hydrogen purities, then hydrogen purity is improved, but hydrogen consumption increases

Engineering Contradiction:

Improvehydrogen purityVSAvoidhydrogen consumption

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The invention segments the monitoring and detection functions into separate dedicated detectors for static seal leaks, shaft seal leaks, and seal oil contamination. This allows targeted identification and treatment of specific leak sources rather than blanket scavenging, reducing unnecessary hydrogen consumption while maintaining purity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary detection and alarm notification before hydrogen purity deteriorates to critical levels. By detecting leaks early through dedicated sensors and alerting operators, corrective actions can be taken proactively to prevent excessive hydrogen consumption while maintaining optimal purity levels.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If seal clearance increases over time, then seal effectiveness deteriorates, but detecting the cause of increased clearance is difficult

Engineering Contradiction:

Improveseal effectivenessVSAvoidclearance increase detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The invention introduces seal oil flow rate as an intermediary measurement parameter that indirectly indicates seal clearance conditions. By monitoring the flow rate of seal oil, the system can detect changes in seal clearance without directly measuring the clearance itself, making the detection process feasible and actionable.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces direct mechanical measurement of seal clearance with flow rate sensing of seal oil. This substitution uses fluid dynamics principles to infer mechanical clearance conditions, enabling detection through more practical and accessible measurement methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If seal oil flow rate increases due to increased clearance or pressure, then hydrogen purity decreases, but identifying the root cause is challenging

Engineering Contradiction:

Improvehydrogen purityVSAvoidroot cause identification

Core Design Contradiction:

Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The invention segments the diagnostic capability by providing separate detectors for static seal leaks, shaft seal leaks, and seal oil contamination. This segmentation allows operators to identify which specific component is causing the purity degradation, making root cause identification straightforward rather than requiring complex analysis of combined effects.

Inventive Principle:

Principle #1Segmentation

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

Enables early detection and mitigation of hydrogen leaks and contamination, improving hydrogen purity and reducing consumption, thereby enhancing generator performance and availability while reducing operational costs.

Implementation Method 1

Seal oil is made to pass through the clearance between the shaft and seal rings at a pressure higher than the cooling gas pressure in the casing

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

In the seal area, seal oil dissolves the surrounding hydrogen and gives up the entrapped air due to the partial pressure change resulting in a decrease in the hydrogen purity levels

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS8344676B2Seal leakage and seal oil contamination detection in generator

Publication Date: 2013.01.01 GE INFRASTRUCTURE TECH LLC

AI summary

Detection of, among other things, seal leakage(s) and/or seal oil contamination for a gas cooled generator are provided. Detectors according to some embodiments of the invention provide mechanisms of early detection of cooling gas, e.g., hydrogen, leakage through leakage sources as well as low purity and high cooling gas consumption problems in a gas cooled generator.