This paper proposes the use a of Battery Energy Storage (BES) on an Unified Power Quality Conditioner (UPQC) supplied by Photovoltaic (PV) through DC link to improve power quality on a three-phase three-wire (3P3W) distribution system. The BES serves to store the excess of power resulted by PV and to transfer it to load if necessary, preventing voltage interruption, and adjusting charging and discharging energy in battery. Power quality analysis is carried out in two conditions i.e. PV connected to DC link without and with BES. Fuzzy Logic Controller (FLC) is implemented to maintain DC voltage across the capacitor under disturbance scenarios of source and load as well as to compare the results with Proportional Intergral (PI) controller. The number of disturbance scenarios is six for each UPQC controller, so the total number of disturbances is 12. The six disturbances are: non-linear load (NL), unbalance and nonlinear load (Unba-NL), distortion supply and non-linear load (Dis-NL), sag and non-linear load (Sag-NL), swell and non-linear load (Swell-NL), and interruption and non-linear load (Inter-NL). FLC method on UPQC supplied by PV with BES is able to result in an average THD of load voltage slightly better than PI controller. In disturbance scenario 1 to 5, nominal of average THD of load voltage have met IEEE 519. FLC method on UPQC supplied by PV with BES is also capable to give average THD of source current better than PI controller. Under scenario 6 (Inter-NL), FLC is able to reduce the average THD of load voltage and source current significantly than PI controller. With the same disturbance, the combination of PV and BES is able to generate power to UPQC DC link and to inject full average compensation voltage through injection transformer on series active filter so that average load voltage remains stable. This simulations prove that the proposed artificial intelligent (AI) controller for UPQC with BES is able to improve power quality significantly under varying disturbances especially for interruption disturbance. The performance of the proposed model is validated and investigated through simulations using Matlab/Simulink.
- Disturbance scenarios
- Power quality
- Total harmonic distortion (THD)