In a rail system powered by DC unwanted electric potentials and stray currents can occur because typically the running rail is used as a return conductor. Due to unavoidable isolation issues of the running rails to earth these electric potentials and stray currents are generated, which can endanger passengers and can damage the infrastructure.
The electro-chemical corrosion occurs, if and when electric currents enter or leave electrically conductive elements like pipes or concrete reinforcements. This situation is depicted in the following drawing:
The system dregisters these potentials and displays them on a central monitor. This is presented in a network plan. Green section show that the potentials are below a threshold, red show that the thresholds have been exceeded.
The measurement systems can be designed as stand-alone systems (e.g. the earth potential meter of Witt) or in combination with an earth short circuiting device (e.g. ESC 100).
The measurement stations collect the data and transfers it to a central evaluation station. The data transmission is done automatically and formatted using TCP / IP protocol via a modem connection or another communication procedure.
The display of the information can be done using a map of the network:
This way the status of the complete network is presented up-to-date, clear and comprehensive in respect to the potentials and stray currents. This allows – in case of an event – a timely and target oriented reaction.
You can get further information by downloading the data sheet: