This paper describes an improved Flexible Alternating Current Transmission System (FACTS)-based custom power controller with dynamic voltage restorer (DVR), static compensator (STATCOM) and unified power quality conditioner (UPQC) topology. The proposed controller can feed the power to grid and proficiently moderate the power quality problems like sag, swell, flicker, voltage interruption, reactive and active power compensation and voltage disturbances with harmonic problems to make sure power quality in the distribution system. The proposed configuration utilizes the Distributed generations (DGs), e.g. Photovoltaic (PV), wind and proton exchange membrane fuel cell stack connected to the micro-grid for realilazisation of DVR, STATCOM and UPQC operation with reduced filtering requirements. Space vector pulse width modulation -based hybrid cascade bottom leg multilevel inverter has been used for this purpose. The proposed topology has been simulated using MATLAB/Simulink and validated experimentally on a practical system. It is shown that the UPQC performs significantly better than the DVR and STATCOM for the improvement of different power quality issues.
- Hybrid cascade bottom leg multilevel inverter
- Dynamic voltage restorer
- Static compensator
- Unified power quality conditioner
- Space vector pulse width modulation
- Proton exchange membrane fuel cell stack
- Power quality
Figure 1. Schematic diagram of the proposed configuration of the micro-grid.
EXPECTED SIMULATION RESULTS:
Figure 2. Simulation output response of the proposed DVR with SVPWM control voltage sag for nonlinear sensitive load with balanced three-phase fault: (a) fault voltage, (b) booster voltage by DVR, (c) load voltage (V), (d) fault current, (e) load current.
Figure 3. Output response of DVR with linear load for phase b, c and ground fault: (a) source voltage (b) DVR injected voltage (c) load voltage (d) load current, (e) active and reactive power.
Figure 4. Response of UPQC with vector control voltage sag for nonlinear load with balanced three-phase fault: (a) fault voltage, (b) UPQC booster voltage, (c) load voltage (V), (d) fault current, (e) load current.
Figure 5. Performance of the UPQC for (a) resistive load with unbalanced voltage sag active and reactive (red) power output, (b) capacitive load with unbalanced voltage sag active and reactive power output, (c) resistive load with balanced voltage sag active and reactive power output, (d) nonlinear load with unbalanced voltage sag active and reactive power output.
This paper investigates the combined renewable sources of PV-wind-PEMFCS-DVR, PV-wind-PEMFCSSTATCOM and PV-wind-PEMFCS-UPQC system for the purpose of simultaneous compensation and active power injection. This proposed method is capable to compensate network power quality issues and mitigate their effects on sensitive loads in distribution power systems. The simulation and hardware outcomes specify the capability of custom power device in mitigating the voltage variation and harmonic polluting loads. The output voltage harmonics is reduced by SVPWM switching for the operation of DVR, STATCOM or UPQC modes. The proposed system also decreases the overall voltage THD in the micro-grid, decreases the total system loss, improves the dc link voltage, increases the effecting speed, solves the loss of commutation, minimizes the harmonics and optimizes the high frequency switching problems. The proposed method is simple and can be easily implemented with the help of already available drive compatible hardware.
 Kadri R, Andrer H, Gaubert J-P, et al. Modeling of the photovoltaic cell circuit parameters for optimum connection model and real-time emulator with partial shadow conditions. Energy. 2012 Jun;42(1):57–67. Available from: https://doi.org/10.1016/j.energy.2011. 10.018
 Bouilouta A, Mellit A, Kalogirou SA. New MPPT method for stand-alone photovoltaic systems operating under partially shaded conditions. Energy. 2013;55:1172–1185.
 Rahim KNA, Ping HW, Selvaraj J. Photovoltaic module modeling using simulink/matlab. Procedia Environ Sci. 2013;17:537–546.
 Dali M, Belhadj J, Roboam X. Hybrid solar-wind system with battery storage operating in grid-connected and standalone mode: control and energy managementexperimental investigation. Energy. 2010;35:2587– 2595.
 Bollen M. Understanding power quality problems: voltage sag and interruptions. New York: IEEE Press; 1999.