An analytic hierarchy process-based novel approach for benchmarking the power quality performance of grid-integrated renewable energy systems

Abstract

The technical, social, economic as well as environmental multi-benefits of renewable energy sources do not come without certain power quality (PQ) challenges, and deterioration of voltage and current quality is foremost among them. Technically, voltage harmonic distortion, current harmonic distortion, voltage and frequency fluctuations and voltage imbalances are the five decisive issues that judge the PQ performance of renewable energy systems. Healthy PQ, in terms of all the aforementioned phenomena, is assured by monitoring and benchmarking their corresponding indices, but performing the same, only at distributed generation (DG) bus level, is not sufficient since also the grid, as well as load bus PQ, plays an important role which makes the overall PQ assessment of renewable energy systems quite complex. This paper presents an analytic hierarchy process-based novel approach for evaluating and benchmarking the PQ performance of grid-integrated renewable energy systems. The procedure results in a single compound power quality index that is alone ample for benchmarking the overall PQ performance of a renewable energy system above the threshold level as well as for ranking among the PQ performances of individual DG systems differentiated by either renewable energy types or sittings in a distribution network. Such a compound index can ease the PQ performance evaluation and benchmarking process up to a maximum extent. Furthermore, it can be very helpful also for distribution system operators to monitor and penalize the DG owners for poorly operating from PQ aspects and motivate the same for adopting best option among different power quality improvement (PQI) technologies. The proposed approach is verified on a grid-integrated PV-based DG system in MATLAB/Simulink. Besides that, the effect of different PQI techniques, on PQ performance, is tested by the application of the proposed approach. At last, the validation of impending effects of high penetration of renewable energy on PQ of the system is also attempted by the proposed approach.