Safe high-current monitoring

In electrically conductive systems with large-scale currents in the kiloampere range e.g., in high-current supplies, connections, junctions or superconducting magnetic coils, monitoring of electrical conductance is of great importance. Excessive drops in electrical conductance may not only cause safety problems but may also destroy the respective electrical conductors due to extreme material heating. This, in turn, causes severe losses of money and high costs of repair. Especially in highly complex systems, fault currents, disturbances, and power drops (e.g. so-called quenches in superconducting systems) thus ought to be detected as sensitively and rapidly as possible. Researchers at Institute for Data Processing and Electronics (IPE) have developed a differential detector system that allows easy comprehensive monitoring in the millivolt range and can be applied reliably during ramp-up and ramp-down of high-current systems. The self-induction voltage generated during high-current ramping causes problems in using commercial voltage meters. Conventional systems cannot differentiate between such voltage and power drops due to reductions in conductance. The new detector uses a voltage difference measurement principle with additional mutual balancing of the conductor sections to be monitored. Due to the thus optimized neutralization of the self-induction voltage already small reductions in conductance can be detected immediately. In addition, the system can be cascaded by grouping different individual sections and correlating the groups obtained with further sections. The stand-alone detectors applied so far in research are conceived as fail-safe components provided with electrical isolation in the double-digit kV range, internal redundancy, and self-diagnosis. Different interfaces allow control of subordinate components as well as connection to superordinate systems such as control rooms. The system has been successfully applied in practice. It is completed by an advanced, technically mature monitoring software.In electrically conductive systems with large-scale currents in the kiloampere range e.g., in high-current supplies, connections, junctions or superconducting magnetic coils, monitoring of electrical conductance is of great importance.