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Integrated photovoltaic (PV) distribution systems voltage stability is of great significance in supporting all connected equipment smooth functioning in the distribution network. Voltage profile maintenance is one of the challenging tasks in PV integration. To maintain a constant voltage profile to a sensitive load of 22 kVA is the main idea of this study. A single‐phase PV‐integrated distribution system is selected for the study. The novelty is that differential inverters are used for dynamic voltage restorer and distribution static synchronous compensator of the unified power quality conditioner (UPQC). Active power decoupling facility is the main advantage using the differential inverter. The research work objective is to synchronise a 10 kW solar PV system to the distribution system using this new UPQC. The research work discusses and derives the most suitable control strategy for the UPQC with battery energy storage system. A 20 kVA UPQC is designed for the PV integration and to increase voltage stability of the distribution system. The frequency, voltage and reactance/resistance ratio of the distribution system is assumed to be constant. A prototype model of differential UPQC is developed. Experimental and simulation results validate the main objective. [ABSTRACT FROM AUTHOR]

This study presents a single stage grid‐interfaced solar photovoltaic (SPV) system using a multifunctional complex coefficient reduced ordered generalised integrator (CC‐ROGI) based frequency‐locked loop (FLL) control. The main contributions of this study, include (i) the extrication of fundamental active components from load currents using CC‐ROGI‐FLLbased control to generate the reference grid currents for voltage source converter (VSC) switching, (ii) VSC works as a distribution static compensator, which performs multi‐functions like harmonics mitigation, reactive power compensation, unity power factor operation and grid currents balancing, (iii) this CC‐ROGI‐FLL also extricates the fundamental grid voltages component even under grid voltage harmonic distortion and grid voltages unbalancing. Moreover, SPV power feed‐forward component is assimilated in this control to reduce the oscillations in grid currents under variable irradiance. Simulated and experimental results show satisfactory behaviour of the system at different conditions like load unbalancing, variable solar irradiance and abnormal grid conditions. The comparative performance of CC‐ROGI‐FLL control with other FLL and phaselocked loop controls are shown in this study. This CC‐ROGI‐FLL control has manifested a good steady state performance and dynamic response. The total harmonic distortions of grid currents are found well within the limits of the IEEE‐519 standard, even under abnormal grid conditions. [ABSTRACT FROM AUTHOR]

This study investigates the mitigation of transient overvoltages (TOVs) in a microgrid supplied by renewable distributed generation resources, which include photovoltaic (PV) generators, hydro generation unit, and wind power generators. ATP/EMTP is used in this study as electromagnetic transient software. Accurate simulation models are needed to carry out the study. Therefore, a three‐phase PV system model based on the equivalent Newton–Raphson circuit is used, and the efficiency of the PV system components is studied. Then, the use of the PV generation system model for switching studies is investigated using two different electrical systems. The use of different mitigation methods for TOVs at the microgrid is investigated. Three different mitigation methods are considered. First, a device to compensate reactive power such as static var compensator (SVC) is represented as a TOVs mitigation method. Then, adding a supercapacitor as TOVs mitigation method is evaluated. After that, a combination of active and reactive power simultaneously to mitigate TOV, by the addition of SVC to a supercapacitor, is investigated. The grid‐connected mode and isolated mode of the microgrid are considered. The results show that the usage of SVC with supercapacitor has the ability to mitigate the transient overvoltage and the waveforms are more regular. [ABSTRACT FROM AUTHOR]

The variable step size modified least mean square (VSSMLMS) learning algorithm based multifunctional double‐stage grid interactive photovoltaic (PV) system is implemented in this paper which feeds power to the grid and the load, ensures unity power factor operation and compensates reactive power. Along with this, it mitigates high grid neutral current during unbalanced loading condition. This algorithm uses variable step sizes to have a smooth dynamic and steady state performances. The boost converter (booster) is used in the first stage to extract peak power from a PV array using perturb and observe peak power point tracking technique. Next to this, a four leg voltage source converter (VSC) is placed to interlink the solar PV system to the grid and the loads. VSSMLMS‐based control technique is used to filter the fundamental component of load current and hence gate pulses are generated for the four‐leg VSC. This system is simulated in SIMULINK/MATLAB software under several working conditions and the obtained simulation results are validated on a developed laboratory prototype. The performance of the VSSMLMS‐based control technique is compared with that of the traditional LMS‐based technique. All results validate the IEEE‐519 standard. [ABSTRACT FROM AUTHOR]

In this study, a double fundamental signal extracter using third‐order signal integrator‐based control technique is used for the improvement of power quality of single phase grid interfaced with hybrid wind energy generation system (WEGS) and solar photovoltaic (PV) array under weak grid conditions. The control algorithm is proposed for the extraction of dual fundamental components of load current and to extract fundamental grid voltage for synchronisation to the grid. The main objective of the system is to establish secure, reliable and safe integration while mitigating several power quality issues such as total harmonic distortion (THD) of the grid current, DC current injection. The system operates in distribution static compensator mode in the absence of renewable energy sources and also, maintains the grid current THD as per the limit of the IEEE‐519 standard. For optimal power extraction from WEGS as well as the solar PV array, perturb and observe algorithm is used. The prototype developed in the laboratory is tested under different operating conditions such as variable wind speed, grid voltage sag/swell, variable solar insolation, and varying load conditions. [ABSTRACT FROM AUTHOR]

Local latency adversely affects the stabilising performance of damping controllers especially in the two‐level control scheme. By considering both wide area and local latencies, this study presents the two‐level coordinated control which consists of wide area centralised and local controls of power oscillation damper (POD) and power system stabiliser (PSS) for robust power oscillation damping. The PODs are equipped with the doubly fed induction generator (DFIG) wind turbine, the solar photovoltaic generator (SPV), and the static VAR compensator (SVC). The centralised PODs of DFIG, SPV, SVC, and the centralised PSSs act as the primary damping controllers. When the communication failure occurs, the local PODs of such devices and the local PSSs are activated and used as the backup damping controllers. To achieve the damping performance and robustness, the parameters of centralised and local controllers are individually optimised based on the worst scenarios determined by the lowest damping ratio of target inter‐area oscillation modes. Study results in New England and New York IEEE 68‐bus system demonstrate that the proposed two‐level coordinated controllers are superior to the conventional two‐level controllers in terms of damping performance and robustness against various operating conditions. [ABSTRACT FROM AUTHOR]