Limiting device for cathodic corrosion protection systems - using low internal resistance earthing connecting for buried high voltage conduits with cathodic protection systems

摘要

The device consists of a number of diodes arranged in a stack and having two connection points, one of which is connected to the steel pipe and the other to the earthing system. The diodes are arranged in the form of a column, and the current forward path is in the longitudinal axis of the column while the current return path is by way of a number of external conductors arranged concentrically around the outside of the column. Each diode is provide with a heat dissipation disc, and the stack is held together by four electrically conducting bolts which pass through the discs but are insulated from them. Each end of the stack has an end plate with which the bolts are electrically and mechanically connected. The steel pipe is connected to one of these end plates, and the earth system is connected to the centre of the column. USE/ADVANTAGE - Used when cathodic corrosion protection systems must be provided for buried steel pipes contg. high-voltage electrical conductors, and allows the pipe to be connected to the earthing system for electrical safety while still maintaining the DC potential required by the cathodic protection system. The proposed device is connected between the pipe and the earthing system and provides a much reduced internal resistance to alternating currents, providing increased electrical safety.