During adjustment and trial operation in Lingao Nuclear Power Station the main and auxiliary transformers have some problems, including the abnormal action of gas relay, total hydrocarbon of the transformer oil and acetylene contents exceeding the standards, crack of O-shape seal ring for load-tap.

Form three practical cases,it is shown that the gas content analysis is a quick and reliable diagnosis method to determine the action causes of gas relay in transformer.

?The thermostatic methane detection with catalytic sensor is a new kind of m easuring technique, which keeps the catalytic sensor in a constant temperature by anautomatic control circuit and improves its properties.

The visualized calibration technology for the intelligent methane detection system is introduced.

Using the embedded technology, optoelectronics technology and the principle of infrared absorption gas detection, a practical value of the embedded dual-beam infrared gas detection system has been designed.

The sensor adopts several gas catalytic elements and takes ATmega128 single-chip microcomputer as control core,and uses least square data fusion algorithm to fuse several detection results of gas concentration,which realizes functions of gas detection and information processing.