Towards digitalized and automated substations: implementation of adaptive protection control unit and monitoring system for modern distribution networks under increased hosting capacity of distributed renewable sources.

Abstract

Maximizing the hosting capacity of modern distribution networks to accommodate more distributed renewable sources is key driver to realise energy system security and Net-Zero carbon goals. Protection systems under increased share of renewable sources became more challenging with diverse topology changes originated from the addition, disconnection, or islanding of distributed generation to secure increasing energy demands. This paper aims to implement an adaptive protection control unit interlinked with an interactive monitoring system to enable the real-world application of smart adaptive protection schemes for modern distribution networks under increased hosting capacity of distributed renewable sources. An adaptive protection control kit is experimentally developed to enable the automatic adjustment of optimal relay settings in response to network topology changes arising from the integration of distributed generation. A set of relay settings are pre-optimized within a small-scale meshed network under possible network topologies and stored offline via a master microcontroller which then uses the online breaker status to identify the corresponding network topology and accordingly adjust the pre-optimized relay settings. A human machine interface is further designed and interlinked with the experimentally developed control kit via a slave microcontroller, providing real-time data of actual current measurements and waveforms together with topological changes and self-adaptation of pre-optimized relay settings. Experimental results showed successful adjustment of pre-optimized relay settings in response to topological changes while achieving coordination time intervals within acceptable limits under the tested network topologies