Stray Current Interference Detection and Drainage Practice of the Changsha Section of a Long - Distance Buried Natural Gas Pipeline

Abstract

The Changsha section of a long - distance buried natural gas pipeline had many accompanying and cross high - voltage transmission lines and high - speed railways. In addition, the metro rail transit line A was recently put into trial operation. All these above made the gas transmission pipeline subjected to mixed interference of AC and DC stray currents, the cathode station potentiostat could not operate stably, and the AC interference voltage of some pipeline sections was up to 18 V. The composite drainage method combining the forced drainage with the negative potential grounding drainage was adopted to solve the problem of mixed interference of AC and DC stray currents, and the polarity drainage and solid - state decoupler grounding drainage methods were analyzed and compared. Results showed that the composite drainage method combining the forced drainage with the negative potential grounding drainage had excellent mitigation effect on the mixed interference of AC and DC stray currents.

Keywords

• stray current|mixed interference|long - distance pipeline|cathodic protection|drainage