Dissolved Gas-in-oil Analysis Of Transformer Using Laser Photoacoustic Spectroscopy Technology

Transformer is the most important and expensive device in the power equipment Malfunction and ageing of transformer can cause severe electrical power grid accident So inspecting the operating condition and health state of transformer in real time can improve security and stability of transformer.At present, dissolved gas analysis (DGA) of transformer is the most accepted method in the world that can inspect and judge incipient malfunctions of oil-immersed power transformer effectively and prevent severe accidents. Laser photoacoustic spectroscopy detection technology has advantage of high detection sensitivity and good ability of anti-interference which has very broad prospects in dissolved gas-in-oil analysis. In this paper, laser photoacoustic spectroscopy detection system is built by utilizing near-infrared tunable fiber laser, erbium-doped optical fiber amplifier and first-order resonant photoacoustic cell. With combinations of wavelength modulation and second harmonic detection technology, the measurement of transformer malfunction gases, such as C2H2, CO2and C2H2/CO2mixed gas is realized. The limit of C2H2and CO2detection sensitivity is12ppb and36ppm respectively.In this paper, when utilizing laser photoacoustic spectroscopy detection system to establish the dissolved gas-in-oil analysis platform of transformer, high-voltage pulse discharge device used for transformer discharge simulation is built adopting Marx-generator. The maximum voltage is100kV and the maximum frequency is15Hz. The simulation of transformer discharge is more real by using the high-voltage pulse discharge device.The dissolved gas-in-oil analysis platform of transformer is built basing on the laser photoacoustic spectroscopy detection system. It consists of high-voltage pulse discharge device, headspace oil-gas separator, circulationand controlsystem et aL Measure the production rate of C2H2quantitatively when simulating the transformer discharge at different voltage levels. Result of experiment shows the production rate of single pulse discharge of C2H2at50kV and60kV is0.0196ml and0.0292ml respectively. The production rate of each pulse discharge of C2H2is increasing when discharge voltage rises.