CEZ Distribuce as a European Distribution System Operator (DSO) with more than 3.6 mil. customers has to be prepared for the future expected development of renewables and EV charging stations in the Czech Republic. The official government document called Czech National Action Plan for Smart Grids published in 2015 by the Czech Ministry of Industry and Trade presents a reference scenario of the future expected development of renewables where PV installations have a major share. In order to find a cost-effective solution for renewables integration, reliability of power supply and power quality for customers, CEZ Distribuce focused during the InterFlex project on testing innovative smart solutions which have a strong potential for large-scale development. The Czech demonstration project, was located in several areas in the northern part of the Czech Republic where CEZ Distribuce operates its distribution grids. The demonstration was not focused only on one area in order to prove replicability and interoperability of the designed solutions, and was divided into 4 use cases:
– UC1: Increase hosting capacity for renewables in LV distribution grids by smart PV inverters equipped with autonomous Q (V) and P (V) function
– UC2: Increase hosting capacity for renewables in MV grids by Volt/VAr control (control of reactive power based on voltage set points)
– UC3: Smart EV charging (autonomous charging power curtailment in case of under voltage or under frequency)
– UC4: Smart energy storage (autonomous discharging of batteries in case of under voltage or under frequency)
The demo focused on the implementation of solutions which are so far not usual in the Czech distribution grids but which have a strong potential for future roll out. Tested solutions covered the most urgent challenges of DSOs – increasing renewables hosting capacity, EV charging stations implementation and energy storage. Beyond the technical developments, the demonstrations also propose grid codes and standards updates in order to secure future smoother integration of selected smart grid solutions. The demonstration confirmed the expectation in terms of increasing of DER hosting capacity in LV and MV grids, and showed the successful implementation of Smart EV charging functions and Smart energy storage concepts, while demonstrating their potential for increasing the flexibility in distribution grids. Based on the project’s KPI evaluation, the DER hosting capacity in LV grids in the Czech demonstration areas was increased up to 76 %, and the DER hosting capacity in MV grids was increased up to 92 % with very low costs for the DSO and DER owners.