No abstract

The foremost problem facing by the photovoltaic (PV) system is to identify the faults and partial shade conditions. Further, the power loss can be avoided by knowing the number of faulty modules and strings. Hence, to attend these problems, a new method is proposed to differentiate the faults and partially shaded conditions along with the number of mismatch modules and strings for a dynamic change in irradiation. The proposed method has developed in two main steps based on a simple observation from the Current versus Voltage (I-V) characteristic curve of PV array at Line-Line (LL) fault. First, the type of fault is detected using defined variables, which are continuously updated from PV array voltage, current, and irradiation. Second, it gives the number of mismatch modules (or short-circuited bypass diodes) and mismatch strings (or open-circuited blocking diodes) by comparing with the theoretical predictions from the I-V characteristic curve of PV array. The proposed algorithm has been validated both on experimentation using small scale grid-connected PV array developed in the laboratory as well as MATLAB/Simulink simulations. Further, the comparative assessment with existing methods is presented with various performance indices to show the effectiveness of the proposed algorithm.

Summary An effective peak current‐limiting control strategy is presented in this paper, for improved dynamic performance of a grid‐connected photovoltaic (GCPV) inverter under unbalanced grid voltages. A simple analysis is developed for calculating the rated inverter power under unbalanced grid voltages without tripping the PV inverter for reliable operation. The active power oscillations induced due to the unbalance in the grid voltages are minimized by equating the active power oscillating terms to zero in the reference current generation. The prime focus of this work is on estimating the reference currents and limiting the inverter currents to rated value and providing low‐voltage ride‐through capability by judiciously balancing positive and negative sequence currents. A prototype hardware is developed in the laboratory and the proposed control scheme is implemented using dSPACE 1103 real‐time controller board. A solar simulator has been used to replicate the PV array. The simulation (MATLAB/Simulink) and the experimental results establish that the proposed controller scheme effectively minimizes the oscillation in active power and limits the inverter currents.

No abstract

The maximum power generation in the solar photovoltaic (PV) array is reduced due to the abnormal conditions such as module mismatch, string faults and damage of the PV modules, which reduces the efficiency and reliability of the system. Conventional protection devices fail to detect the faults, which leads to protection issues and fire threats in the PV plants. This paper proposes a new fault detection algorithm to identify the faults in the PV array and the PV string. A simple analysis is developed for fault detection under different fault conditions, such as line-line (L-L) fault, line-ground (L-G) fault and short-circuit fault with multiple strings, and the values of their current indicator and threshold are predetermined. Based on these values, the proposed fault detection algorithm identifies the fault in the PV array and the PV string, with a reduced number of current sensing devices. The effectiveness of the proposed algorithm is tested and verified through MATLAB simulation and experimentation under various operating conditions of the solar PV plant. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.