Leakage current alleviation in solar energy conversion system enabling power quality improvement

Abstract

This work presents a generalised integrator-based control algorithm for power quality (PQ) amelioration of the grid in the presence of non-linear load enabling leakage current suppression feature. Owing to the presence of stray capacitance between solar photovoltaic (PV) array and the ground, the variation in common-mode voltage across stray capacitance leads to potential safety issues, electromagnetic interference, and distortion into the injected grid currents. Furthermore, the PQ of the grid is highly deteriorated under the existence of non-linear loads. To solve the aforementioned issues, the harmonic compensation controller is presented herein to ensure the unity power factor operation, harmonic compensation, leakage current suppression using the grid-connected solar PV array system. Simulated results show the effectiveness of the control strategy under various operating scenario. In contrast to the state-of-the-art techniques, the grid currents are attained sinusoidal and balanced even in the presence of unbalanced non-linear load. Furthermore, the leakage current is suppressed within 300 mA as per the VDE-00126-01 standard. The comparative performance explicitly validates the effectiveness of the presented harmonic compensating strategy over the conventional schemes. Test results manifest the response of the solar PV array system for various operating conditions and follows the revised IEEE-519-2014 sand VDE-00126-01 standards.

Power quality improvement using three‐phase transformerless grid interfaced SECS enabling leakage current suppression

“…Likewise, the fundamental amplitudes for current in phase “b” and “c” ( I bp , I cp ), are evaluated and processed to compute the load component. The net load component ( I load ) is expressed as [3, 43], …”

“…The typical value of leakage current is slightly increased rather than its nominal operating scenarios. The performances of the SECS using traditional controller [3] are depicted in Figure 11(b). Figure 11(b) shows the dynamics of v sabc , i sabc , Q , I leak for H7 inverter coupled SECS.…”

“…Furthermore, the leakage current is also sustained within limits as per VDE and NB/T standards. The system follows the IEEE‐519, IEC‐61727, VDE‐00126, NB/T‐32004 standards in contrast to the state‐of‐art controller [28] and traditional algorithm [3].…”

“…However, galvanic isolation increases the weight, cost and decreases the overall efficiency of the SECS, thereby, researchers have presented transformerless grid interfaced SECS in [10,11]. Researchers have identified the existing possible parasitic capacitance in the SECS [3,[8][9][10][11]. There are typically three different capacitances, 1) solar film to the glass, 2) solar film to roof surface area and 3) solar film to the grounded support frame.…”

“…Therefore, the solar photovoltaic (PV) array system is booming as distributed power generation. However, various challenges such as leakage current [3][4][5][6], stability [6,7] etc., are still there while integrating the SPG to the grid. Owing to these issues, researchers have presented different topologies in [8,9] for grid-tied solar energy conversion systems (SECS).…”