Evaluation of LV distribution network with active network management under fault conditions

The electrification of heat and transport, and the increased penetration of distributed generation (DG), have the potential to significantly impact thermal constraints, voltage saturation and fault levels of Northern Ireland Electricity Networks (NIEN) ‘last mile’ low-voltage (LV) networks. To avoid/defer expensive reinforcement to address such challenges, NIEN in collaboration with WSP will trial active network management (ANM) scheme to maximise the utilisation of existing assets with flexibility that can benefit from sharing spare capacity between neighbouring LV networks. To do so, an approach to change the configuration and operation of stressed LV networks from ‘radial’ to ‘meshed’ will be considered. However, such a radical change in the network configuration will require LV protection strategies to be re-evaluated. In response to this, this study provides the following contributions: (1) presenting an overview of the NIEN ANM scheme, (2) investigation of the potential impact on the LV protection when the NIEN ANM is implemented (through modelling and simulation studies under different short-circuit fault conditions), and (3) providing recommendations on LV protection arrangements that are required to deliver reliable protection operation with a good level of selectivity for enabling resilient operation of the ANM scheme.