Network housekeeping with stretched low voltage limits

This paper looks into solutions a grid operator has to cope with, taking into account high penetration of high penetration of renewable sources and new loads in the LV grid. Next to that it answers the following main research questions: - what will happen when the low voltage limits will be stretched from ±10% (current value) to e.g. ±15% (with or without time limitation)? - what must a DSO do to realise such a change (technical, legal, ….)? To answer these questions a literature study, simulation, tests and extensive surveys amongst key stakeholders were performed. Finally, recommendations and alternatives are proposed towards the community of DSOs following EN50160

Efficient Control of Active Transformers for Increasing the PV Hosting Capacity of LV Grids

The increased penetration of grid-connected photovoltaic (PV) systems in low-voltage (LV) grids creates concerns about overvoltage in these grids. The proposed methods to prevent overvoltage, such as reactive power absorption by PV inverters and active power management of customers, focus on decreasing the voltage rise along LV feeders, and the potential of active medium-voltage to low-voltage (MV/LV) transformers for overvoltage prevention has not been thoroughly investigated. This paper presents the application of active MV/LV transformers for increasing the PV hosting capacity of LV grids. The potential interferences between the operation of active transformers and the reactive power absorption by PV inverters are investigated, and a voltage droop control approach is proposed for the efficient control of these transformers during high PV generation periods. The proposed method can potentially increase the PV hosting capacity of the grid, while eliminating the need for a complex and centralized controller. The voltages of specific locations or the grid state estimations provide adequate data for adjustments of the droop parameters. The simulations and field test results associated with the implementation of the proposed method to a newly developed active LV grid with high PV penetration in Felsberg, Germany, confirm the efficiency of the proposed method

Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Developing novel technologies and services for intelligent low voltage electricity grids: cost–benefit analysis and policy implications

The paper presents a set of prototype smart grid technologies and services and validates the economic viability of the proposed solution using cost–benefit analysis (CBA). The study considered the EU-funded project called RESOLVD and implemented the technologies and services in a real-life pilot. the technologies and services on the EU-funded H2020. The paper focuses on the analysis of technological solutions which enhance the operational efficiency and the hosting capacity of low-voltage electricity distribution grids. The solutions provided better integration of a hybrid battery storage system, with the grid interfacing power electronics, smart gateways for the interconnection of assets at the grid edge, and sensors enhancing infrastructure observability and control. The result from the CBA indicates the economic viability of the project, high scalability, and replicability. The economic benefits were realized with the breakeven value of eight secondary substations (SS) and 16 feeders. The scenario test on the DSO’s willingness to pay for the software as a service (SaaS) revealed that the payback period can further be reduced by almost half with a higher internal rate of return (IRR) and net present value (NPV). Both the CBA and scenario tests showed RESOLVD solution can become more economically viable when deployed in largescale. Moreover, the CBA results provide evidence to the energy policy by allowing DSOs to consider both CAPEX and OPEX for better investment decisions. Further, the paper proposes an alternative business approach that shifts from grid reinforcement to service provision. The paper also discusses the research implications on energy policy and business.Peer ReviewedObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats SosteniblesPostprint (published version

Increasing Distribution Grid Hosting Capacity Through Wire And Non-Wire Solutions

Increased deployment of distributed generation (DG) can adversely impact the operational performance of distribution networks. This increment can potentially change network power flow and result in several operational issues such as reduced power quality, overvoltage, and ineffective protection. In order to quantify the degradation bounds of distribution operation due to increasing DG integration, the concept of hosting capacity is introduced. The aim of this thesis is to increase the DG hosting capacity in distribution network by proposing several wire and non-wire solutions. To this end, these solutions include network reconfiguration, reactive power control, and energy storage system deployment. The network reconfiguration can change the power flow in the system while the reactive power control can decrease the voltage rise and power loss in the system, which lead to increase in hosting capacity. The energy storage systems can be utilized to locally capture DG generation, which leads to an increase in the hosting capacity. This thesis introduces an optimization- based hosting capacity method developed based on a linear power flow model to optimally determine DGs hosting capacity. Numerical simulations on a radial distribution test system illustrate the effectiveness of the proposed solutions