Dedicated page In August I wrote a dedicated page on this subjectparticularly on my persona experience having a home in a town where two nearby wind farms have been proposed. Maybe I should delete this section, or maybe I'll leave it for possible historical interest?
Opening up machines for inspection is expensive, and owners need to consider all relevant information in making the decision. Problems in steam turbines which reduce machine efficiency and output, such as deposits on blades and erosion of internal clearances, can be detected and monitored using condition monitoring by performance analysis.
The paper outlines with some examples some condition monitoring techniques which have contributed to running some large machines for up to 17 years without opening high pressure sections.
In machines with an HP-IP opposed-flow casing, increased N2 packing internal steam leakage can occur from the high pressure turbine section into the intermediate pressure section has a large effect on output and efficiency. The application of a simple test method for estimating this leakage explained observed poor performance on two sets.
Such operation at steady outputs can lead to deposition from the steam on the fixed and moving blades. Deposits cause output and efficiency to drop, by reducing the efficiency of energy transfer and eventually restricting steam flow. This occurs less on sets which vary in load, as they undergo a regular bladewashing effect.
Where a machine is taken from service, coastdown and running up through shaft bending critical speeds can allow momentary rubbing at the internal seals.
The resulting enlarged flow area can reduce the internal efficiency, such that less energy is extracted from the steam.
This also results from internal leakage within a casing which allows steam to bypass blading stages. These effects are particularly evident on the turbine design with both High Pressure and Intermediate Pressure sections in the one casing, with flow in opposite directions.
Retractable packings have been developed by manufacturers and after-market suppliers. These avoid shaft rubbing as they do not close into their normal clearances until the machine is near operating speed, having passed through the bending critical speed or speeds.
Vibration analysis can detect the occurrence of such shaft rubbing and other conditions of the rotor line, but cannot detect the extent of internal wear or deposition.
It is well suited for other quite different failure modes, such as when blades or parts of them come off and cause consequential damage. As steam turbines are critical machines, all the main techniques have their place.
Performance analysis can be applied to most machines, rotating and stationary. It is the one condition monitoring technique which allows the optimum time for restorative maintenance to be calculated, where the deterioration results in increased fuel consumption, or in reduced output, or both.
Beebe For some plant items, it is possible to use the normal plant instruments and data processing system to determine condition parameters.
In the case of steam turbines, a more refined method using test quality instruments is needed to give warning well in advance of changes evident from permanent instrumentation systems. This paper describes some performance tests used for monitoring turbine condition and their application.
Manufacturers vary in their recommendations for opening up a casing for inspection and refurbishment. Manufacturers have a vested interest in supply of spare parts, and therefore cannot be expected to be unbiased in their recommendations. The author well remembers walking through the works of one manufacturer and seeing several HP casings in for overhaul.
The accompanying engineer said "off the record" that most of them would not justify the work!
An outage for such work on one casing may take several weeks, and cost millions of dollars. In making this decision, plant owners need all the relevant information. BeebeVetter et al The overhaul decision should not be made unless there is a compelling technical or economic reason for opening a casing.
It should be accepted that an outage after such a long time in service will probably take longer than if scheduled more frequently, as distortion is likely to have occurred, and parts such as casing studs will probably need replacement Coade Once a casing is opened and clearance measurements made, it is possible to estimate the performance improvements achievable by refurbishment and so justify the expenditure Kuehn ; Sanders However, it is clearly preferable to try and determine the internal condition by testing, and use this information to help make the decision as to the extent of overhaul.
In Table 1, the main wearout problems with steam turbines are summarised, together with an outline of how how condition monitoring can detect them.Structural Health Monitoring of Wind Turbine Blades using Unmanned Air Vehicles Smita Shivaram, regardbouddhiste.com Structural and Condition Monitoring of Wind Turbines The aim of this dissertation is to address di culties in using computer vision techniques to perform health monitoring of rotating civil structures which cannot.
An unbiased and informed discussion of many of the more contentious features of wind power and wind farms. There are some real problems with wind turbines and there are a number of alleged problems that are unfairly used by opponents of wind power to discredit the technology.
The relationship between wind farms and local climate including rainfall. An Investigation into Vibration Based Techniques for Wind Turbine Blades Condition Monitoring This research work reports the development of condition monitoring (CM) for early fault detection in wind turbine blades based on vibration measurements.
The research started. Condition monitoring of wind turbines: Techniques and methods. (and hence wind turbine) condition based on techniques including vibration analysis, acoustics, oil analysis, strain measurement and thermography.
On WTs they are used to monitor the status of critical operating major components such as the blades, gearbox, generator, main. Tidal power or tidal energy is a form of hydropower that converts the energy obtained from tides into useful forms of power, mainly electricity..
Although not yet widely used, tidal energy has potential for future electricity regardbouddhiste.com are more predictable than the wind and the regardbouddhiste.com sources of renewable energy, tidal energy has traditionally suffered from relatively high cost and.
We are a family-owned, professional, cleaning services company servicing the NJ area. We have the equipment and staff to handle your house and office cleaning needs.