Abstract: A system for measuring a voltage differential in a current-carrying pipe using a propulsion vehicle for conveying the system inside the pipe, the system comprising a first contact for maintaining electrical contact with the pipe as the vehicle moves through the pipe, a second contact positioned in a spaced apart relationship from said first contact for maintaining electrical contact with the pipe as the vehicle moves through the pipe, and a voltage reading device connected to said first contact and said second contact for measuring the voltage between said first contact and said second contact as the vehicle moves through the pipe.

Abstract: A system and method for measuring a voltage differential in a current-carrying pipe using a propulsion vehicle. The system may be adapted for use with a pipeline pig or other propulsion device, which is configured to determine the electric current in a pipeline with nominal noise while the apparatus is moving. One aspect of the present invention is a pig which is outfitted with electrical contacts. These electrical contacts may optionally consist of rotating steel brushes and/or rotating steel knives. The pig includes data logging capabilities which may record location and voltage data. A pig according to the present invention optionally may include electromechanical devices which reduce electrical noise.