To satisfy this requirement

most of the electrical utilities run standard dissolved gas analysis（DGA）.As summarizing disadvantage of current theories used in real-time gas concentration measurement

an on-line DGA system which mounted PTFE membrane

gas sensors

weak signal detection module

wireless communication module is developed.Compared with GC result of DGA

for hydrogen detection

the biggest error of the system is 2×10-6 at rang of（4

2

00）×10-6;for carbon monoxide detection

the biggest error of the system is 30×10-6 at range of（100

2

000）×10-6.The system can meet the requirement of on-line DGA.An additional potential of cost reductions and safely improvements can be achieved.