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This paper deals with the concept development and laboratory testing of an adaptive protection system for distribution networks with distributed energy resources. Adaptation of protection relay settings according to currently available short-circuit current at respective grid nodes, is one solution to cope with the challenges originating from distributed generation. The challenges in conventional protection systems in low and medium voltage grids are discussed and a new concept of an adaptive network overcurrent protection is developed. The soft- and hardware realization of the concept are described and first results of laboratory tests are presented

This paper describes a new high-speed HVDC line protection using wavelet technique, Based on the representation of the tavelling waves through wavelet modulus maxima, the protection criterions for HVDC line are proposed. Simulations are carried out for testing the criterions. And the influences of similar faults are discussed. The protection can detect the HVDC line fault well and identify the HVDC line fault clearly from the similar transients, such as commutation failure and AC single phase fault.

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An approach for a real time adaption of the dead time for auto-reclosing on high voltage lines was proposed. The objective was the optimal adaption of the dead time of a currently running single-phase auto-reclosing cycle by calculating the secondary arc current based on measurements. The algorithms for optimization were performed for real time application. For this purpose, the fault location plus the load currents of the parallel non-faulty conductors were measured. The measurement and the calculation of the dead time took place during the fault and the dead time period. In this way, an optimized dead time setting with regard to the actual fault location and loading conditions were achieved. This approach results to an on-line determination of a minimum necessary dead time of a successful reclosing under consideration of the fault location and prevailing loading conditions. Analytical calculations and numerical examples as well as high voltage field tests verified the results.