| Air switchgear plays an important role in the distribution network.The timely opening and closing operation of the air switchgear ensures the personal safety of the power equipment operator and the stable operation of the power system.In the long-term operation of the air switchgear,the partial discharge（PD）caused by various defects in the air switchgear will cause the air to decompose,which generating O3,CO,NO2 and other decomposition products.So the detection of partial discharge in the air switchgear is of great significance.At present,there are many detection methods for partial discharge of air switchgear.Based on the gas component analysis method,Pd O-Zn O（Pd O composite Zn O nanomaterial）and GO-WO3（graphite oxide composite WO3nanomaterial）gas sensor is prpared in this paper to detect air switchgear partial discharge characteristic gas NO2.And based on the production of NO2 sensor,a online monitoring system is designed to detect air switchgear partial discharge.The main work carried out in this paper and the main conclusions are as follows:（1）The porous snowflake-like Zn O nanomaterial is synthesized by hydrothermal method.On its surface composite Pd O nanoparticles,using the catalytic effect of Pd O to improve its gas detection performance,then a new type of Pd O-Zn O gas sensor is prepared.This gas sensor has a good microscopic morphology,and the snowflake-like multi-layer porous structure has a large specific surface area,which can provide more adsorption sites for NO2 and improve the response to NO2 gas.The optimal operating temperature of the sensor is 250°C,the lowest detection is 100 ppb（parts per billion）.Meanwhile the response to 100 ppm（parts per million）NO2 gas can reach 44.06.It has good repeatability and selectivity,and the sensor response shows a good linear relationship to different concentration NO2gas;（2）Due to the high working temperature of the prepared Pd O-Zn O sensor,which limits the use environment and conditions of use of gas sensor.It is of great significance to make a NO2 sensor which can use at room temperature.Based on the thermal decomposition method,WO3 nanopartics are prepared.Since the small resistance of GO at room temperature can effectively reduce the base resistance of WO3 at room temperature,and the heterogeneous structure of n-GO-p-WO3 can improve the response of WO3 sensors at room temperature,so GO-WO3 sensors are prepared for the detection of NO2 gas at room temperature.The sensor has a response 1157%to 100 ppm NO2 gas at room temperature with a lowest detection of 500 ppb.The sensor has good repeatability and selectivity,and the sensor response shows a good linear relationship to different concentration NO2gas;（3）Based on the NO2 sensor prepared in the paper,the air switchgear partial discharge online monitoring system was designed.And the performance of the designed online monitoring system was verified through simulation experiments,and the error of 2.6%also fully confirmed that the performance of the designed online monitoring system was very reliable.Through the experiments in this paper,it can be found that it is feasible to detect the local discharge of air switch by gas sensor,and the research results of this paper will provide a reference for the future gas sensor method to detect partial discharge of air switchgear. |
