RESEARCH ARTICLE Optimized reactive power support strategy for photovoltaic inverter to intensify the dynamic voltage stability of islanded microgrid Nadia Afrin | Fuwen Yang | Junwei Lu School of Engineering and Built Environment, Griffith University, Gold Coast, Queensland, Australia Correspondence Nadia Afrin, School of Engineering and Built Environment, Griffith University, Gold Coast, QLD, Australia. Email: nadia.afrin@griffithuni.edu.au Peer Review The peer review history for this article is available at https://publons.com/publon/ 10.1002/2050-7038.12356. Summary This study presents an innovative and optimized reactive power support (ORPS) strategy for photovoltaic (PV) inverters to improve the dynamic voltage stability (DVS) of islanded microgrid (MG) with induction motor (IM) load. On the occurrence of the fault, voltage instability (VI) happens due to the low-inertia IM load and poor ride through capability of PV inverters of MG. Supplement of optimal RPS promptly, without exceeding the rated cur- rent value of the inverter, is aimed at the proposed control, to maintain DVS during severe voltage downfall as a result of a fault. Once the profiled voltage value is restored and the necessity of RPS is fulfilled, the PV inverter returns to its prefault power production combination. The detailed model of an inverter- based islanded MG with IM load is built to examine the DVS, and the theoreti- cal analysis and technical discussion are conducted. A comparison between the conventional and proposed strategies is carried out. From the demon- strated results, employing the proposed ORPS control can provide RPS effec- tively and helps to improve the DVS. This proposed strategy can also provide an equivalent service as an expensive 610-kVA dynamic volt-ampere reactive support device (ie, D-STATCOM) in the studied MG. KEYWORDS dynamic voltage stability, islanded MG, PV inverter, reactive power support strategy List of Symbols and Abbreviations: 3LG, Three-Phase to Ground; η, Proposed proportionality constant; ω g , Measured angular frequency; ω n , Nominal angular frequency; ω ref , Reference angular frequency; v g , Phase voltages; C f , Filter capacitor; CI, Constant Current; CP, Constant Power; CPC, Constant Peak Current; CZ, Constant Impedance; CRPS, Conventional Reactive Power Support; D p , Active power droop gain; D q , Reactive power droop gain; D-STATCOM, Distributed Static Synchronous Compensator; DVS, Dynamic Voltage Stability; FIDVR, Fault Induced Delayed Voltage Recovery; FRT, Fault Ride Through; IM, Induction Motor; IEEE, Institute of Electrical and Electronics Engineers; I q0 , Injected reactive current component at normal operating condition; I rated , Rated current of the inverter; I ref_dnew , New reference active current component; I ref_d , Reference active current component; I ref_qnew , New reference reactive current component; I ref_q , Reference reactive current component; k, Reactive current scaling factor; K ic , Integral gain of current control loop; K ip , Integral gain of reference frequency generator; K iq , Integral gain of reference voltage generator; K iv , Integral gain of voltage control loop; K pc , Proportional gain of current control loop; K pv , Proportional gain of voltage control loop; MG, Microgrid; ORPS, Optimized Reactive Power Support; PV, Photovoltaic; pf, Power Factor; P D , Droop active power; P M , Measured active power; P S , Set active power; p f , Power factor; RPS, Reactive Power Support; RES, Renewable Energy Source; TVSI, Transient Voltage Severity Index; VI, Voltage Instability; VAr, Volt-Ampere reactive; VSG, Virtual Synchronous Generator; V base , Base voltage; V dip , Voltage dip; V ref , Reference voltage. Received: 27 June 2019 Revised: 19 December 2019 Accepted: 30 January 2020 DOI: 10.1002/2050-7038.12356 Int Trans Electr Energ Syst. 2020;e12356. wileyonlinelibrary.com/journal/etep © 2020 John Wiley & Sons Ltd 1 of 16 https://doi.org/10.1002/2050-7038.12356