Future standardisation requirements for dependable overcurrent protection in intentionally islanded LV microgrids build by distributed inverters

Abstract

The preconditions for dependable overcurrent protection of customer installations are largely unknown in islanded low‐voltage (LV) microgrids build by multiple droop controlled and current limited inverters. Consequences may be an islanded operation with limited reliability of supply, investments of uncertain necessity or uncontrolled hazards. Distribution system operators will not opt for intentional islanding until those risks become predictable. Extensive variation studies are therefore performed to screen for decisive influencing factors and to quantify their effect by means of computer simulations in Matlab/Simulink ® . First steps of a standardisation roadmap are drawn that will either enable developing the preconditions for a dependable overcurrent protection or choosing effective alternatives. An initial set of quantitative minimal conditions is given as a basis for further discussions.