Extensible distribution grid automation using IEC 61131 in simulation and operation

The implementation of active distribution grids as a precondition for the smart energy system requires a decentralized automation approach that is based on proven technologies and standards allowing for flexible extensibility of power grid automation functions. In a decentralized automation approach the secondary substations play a major role and need to be equipped with reliable measurement and control technology. This suggests the use of programmable logic controller (PLC) technology as described by the IEC 61131 standard. Existing secondary substations can be upgraded by such PLC-based systems to provide not just monitoring and remote control but also advanced smart grid functions. The key challenge of future-prove distribution grid automation is the extensibility of these functions in order to satisfy new requirements. Functional extensibility demands modularization and composability which is provided by IEC 61131-3 standard in form of function blocks. The development, evaluation and application of advanced power grid monitoring and control functions requires tools for integrated simulation of function blocks and the power grid model. Such a tool is developed in the research project MD-E4 based on the SIMBA# simulation platform. It is applied for design and evaluation of IEC 61131 based power flow, state estimation and control functions, which are also evaluated in practice by running on physical PLCs that are installed in secondary substations in the distribution grid of Magdeburg.