Analysis of the influence of the HVDC transmission interference on the dominant azimuth of geoelectric field at Jiangyou Seismic Station and Yanyuan Seismic Station
The dominant azimuth method of geoelectric field is used to study the geoelectric field of Jiangyou Seismic Station and Yanyuan Seismic Station in Sichuan Province.The original daily variation minute data of two stations during the period of HVDC transmission interference are selected for calculation and statistical analysis.It is found that:1.The amplitude,start and end time of interference in different days of the two stations are different.For example,there may be multiple HVDC transmission interference events in one day,as a result,the daily variation data shows a square wave shape.In addition,there may be HVDC transmission interference lasting for many days,which shows a continuous square wave change on the geoelectric field time series curve.2.The occurrence time of HVDC transmission in different direction finding of the station is consistent,for example,the observation curves of geoelectric field data at Jiangyou and Yanyuan stations show a jump at the same time.3.On the day when the two stations are interfered by HVDC transmission,both of the dominant azimuths at Jiangyou and Yanyuan stations show a decreasing change.4.The trend changes of the dominant azimuth of the two stations during the continuous interference period is different.The Jiangyou Station shows tight abnormal changes,while the Yanyuan Station shows downward fluctuations.