Generator Leak Detection Using Controlled Pressure Equalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional leak testing methods for hydrogen and liquid cooled electrical generator stator casings are time-consuming, costly, and prone to inaccuracies due to environmental factors, requiring extensive equipment and lengthy testing periods, which can lead to delayed detection of leaks and increased downtime for power generating stations.
Innovation Solution
A novel device and method utilizing Boyle's Law and Bernoulli's Principle, combined with laboratory-derived algorithms, to measure leak rates using a high-pressure differential pressure gauge and custom orifices, allowing for rapid detection and quantification of leaks from minute to large rates, independent of test volume and ambient conditions, reducing testing time to under three hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pressure and vacuum decay testing methods are used, then leak detection can be performed, but the testing time is excessively long (24-48 hours or more) and the process is complex
Solution Approach 1:
The patent changes the testing parameter from traditional pressure/vacuum decay over 24-48 hours to a rapid pressure equalization method that achieves leak detection in minutes. The system uses a controlled pressure equalization process where the pressure differential is rapidly established and monitored, fundamentally changing the time scale of the measurement while maintaining accuracy through precise differential pressure gauges and controlled airflow through known orifices.
Solution Approach 2:
The patent segments the leak detection process into distinct stages: (1) isolation of the test volume, (2) rapid pressure equalization through controlled orifices, (3) monitoring of pressure differential over a short time period, and (4) calculation of leak rate. This segmentation allows each stage to be optimized independently, particularly the pressure equalization stage which uses precisely sized orifices to control the rate of pressure change.
2Reliability
If traditional drying processes (gravity drainage and pressurized air blowdown) are performed before leak testing, then moisture removal is achieved, but the process time is extended by 24-48 hours
Solution Approach 1:
The patent performs preliminary moisture removal actions before the actual leak testing begins. The system uses rapid pressurization with dry air or nitrogen followed by immediate cooling, which condenses and removes moisture from the test volume before the pressure equalization measurement starts. This preliminary action ensures the test volume is dry without requiring the extended 24-48 hour drying period of traditional methods.
Solution Approach 2:
The patent skips the traditional lengthy gravity drainage and extended blowdown process by using rapid pressurization followed by rapid cooling to achieve moisture removal in minutes rather than hours. The system rushes through the moisture removal process by controlling the pressure and temperature changes to rapidly condense and expel moisture from the test volume.
3Measurement precision
If conventional time-weighted pressure decay testing is used for large volume generator casings, then leak rates can be calculated, but the results are inaccurate due to environmental temperature and pressure changes
Solution Approach 1:
The patent introduces an intermediary controlled environment for the pressure measurement process. The system uses insulated pressure equalization chambers and controlled airflow paths that isolate the measurement process from external environmental fluctuations. The differential pressure gauges are protected from temperature changes, and the pressure equalization process occurs in a controlled time frame that minimizes environmental influence.
Solution Approach 2:
The patent uses periodic pressure equalization cycles where the system rapidly establishes a pressure differential, monitors it over a short standardized period, then resets. This periodic action allows for multiple rapid measurements that can be averaged, reducing the impact of transient environmental fluctuations on the overall measurement accuracy.
4Reliability
If both vacuum decay and pressure decay tests are performed to detect all types of leaks, then comprehensive leak detection is achieved, but the testing complexity and time requirements increase significantly
Solution Approach 1:
The patent creates a universal pressure equalization testing method that can detect both vacuum-type leaks (where insulation closes under vacuum) and pressure-type leaks (where insulation opens under pressure) within a single test procedure. The system performs rapid pressure equalization from both vacuum and positive pressure states, allowing one test method to serve multiple detection purposes that traditionally required separate vacuum decay and pressure decay tests.
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 solution provides accurate, repeatable, and portable leak rate measurements, saving significant time and resources by eliminating the need for lengthy drying processes and minimizing downtime, while ensuring precise detection of leaks, thus reducing the risk of moisture migration into insulation systems.
Implementation Method 1
measuring the pressure differential across the generator casing to determine if a leak exists
Implementation Method 2
A novel device and method utilizing Boyle's Law and Bernoulli's Principle, combined with laboratory-derived algorithms, to measure leak rates
Implementation Method 3
A novel device and method utilizing Boyle's Law and Bernoulli's Principle, combined with laboratory-derived algorithms, to measure leak rates
Implementation Method 4
the higher pressure hydrogen will infiltrate the water passage to prevent and/or delay moisture from leaking or 'wicking' via capillary action into the generator stator armature coil insulation
Data Source
AI summary
A device, system, and method for detecting a leak (and determining the leak rate of the leak) for equipment, particularly generators, the device including a main body connected to the tested equipment and to an air supply source, wherein the main body includes a number of stages each having a valve and orifice such that flow of air through the independent stages is selectively controllable, where a change in the differential pressure recorded during flow of the air through a particular stage indicates a leak, and wherein the differential pressure recorded can be used to calculate the rate of leak in the equipment.