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Turbine measurement at Connahs Quay

Turbine measurement at Connah`s Quay

Specialist non-contact temperature measurement equipment for monitoring turbine blades has been supplied to Connah`s Quay power station by Land Infrared.

The Land turbine blade temperature measurement system (TBTMS) is the second to be installed in the UK. The first was at Rye House.

The TBTMS is claimed to be much more accurate than the traditional method of calculating turbine blade temperatures from exhaust gases, which cannot detect the variations that frequently occur across a row of blades.

It monitors each air-cooled blade directly and continuously by means of an array of infrared radiation thermometers, providing a wealth of data which is used to fine tune turbine firing rates to detect blocked cooling channels and, in extreme cases, to prevent blade failure and consequent damage to other turbine components.

At Connah`s Quay, three TBTMS thermometers have been fitted to each of the stations four turbines. Each system can include up to 32 thermometers with individual key phasor conditioner/power supply modules; a multiplexed data acquisition system with associated on-line software, and Land`s off-line data presentation software TBTMS for Windows.

Mounted in penetrations through the turbine casing, the thermometers view the rotating blades through a pressure-proof sight glass assembly purged with compressor air to ensure a clear line of sight.

Optical signals collected by each thermometer are transmitted via a flexible light guide to a signal conditioner providing four linear 4-20 mA outputs. These provide a high speed temperature profile signal sent to the data acquisition system for data logging, and average peak signals for interface to the customers DCS or other equipment.

Using high speed photo-detectors and analogue and digital electronics, the data acquisition system captures a sequence of approximately 3000 temperature readings over one complete revolution of the blade array. These form a thermal “fingerprint” which is stored to hard disk, and to remote drive via an ethernet local area network.

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