Experimental Analysis of Power Quality in a Power Substation Used in a Residential and Educational Sector

The article describes the experimental measurements made at a low-voltage residential and educational power substation, in a point of common coupling. Two groups of experiments were carried out, in normal conditions and during the COVID-19 pandemic. Measurements were made using a power quality analyzer and include phase RMS voltages and line currents, total harmonic distortion and unbalance of phase voltages and line currents, neutral current, active, reactive and apparent powers, power factors and displacement power factors, Fresnel diagrams, and harmonic spectra. Measurements indicate significant differences of power quality indicators between the two measurement groups. © 2023 IEEE.

Dynamic Frequency Analysis of the Jordanian Power System with Significant Penetration of Renewables: Lessons Learnt from the COVID-19 Lockdowns

The increasing dependence on renewable energy particularly solar Photovoltaic (PV) to supply energy consumption needs in Jordan has placed operational challenges on the power system operator to cope with the significant drop in the system's net-demand and the reduction in synchronous inertia. These challenges were not expected to become critical until the penetration of renewables increases to meet future national energy targets in the forthcoming years. However, the adoption of lockdowns to restrict the outbreak of COVID-19 combined with PV injections reduced the system's net-demand particularly during daytime in spring 2020 like expected levels in the future with high PV penetration. Thus, the implications of future significant penetration of renewables on system security could be better understood based on the operating conditions during lockdowns. In particular, it is important to assess the system's frequency adequacy during emergency events that might be occurred whilst running a low-inertia power system. To do so, this paper provides a detailed dynamic frequency analysis of the Jordanian power system during lockdowns using Power Factory software. The results highlight the importance of energy curtailment of renewables to maintain adequate level of synchronous inertia to maintain security when the system is islanded without interconnections to neighboring countries. However, deciding the proper level of curtailment requires performing dynamic analysis to ensure that both the Rate of Change of Frequency (RoCoF) and the minimum frequency level during generation contingency events will not trigger the Under Frequency Load Shedding (UFLS) relays. © 2022 IEEE.