Grid-connected rooftop and ground-mounted solar photovoltaics (PV) systems have gained attraction globally in recent years due to (a) reduced PV module prices, (b) maturing inverter technology, and (c) incentives through feed-in tariff (FiT) or net metering. The large penetration of grid-connected PVs coupled with nonlinear loads and bidirectional power flows impacts grid voltage levels and total harmonic distortion (THD) at the low-voltage (LV) distribution feeder. In this study, LV power quality issues with significant nonlinear loads were evaluated at the point of common coupling (PCC). Various cases of PV penetration (0 to 100%) were evaluated for practical feeder data in a weak grid environment and tested at the radial modified IEEE-34 bus system to evaluate total harmonic distortion in the current (THDi) and voltage (THDv) at PCC along with the seasonal variations. Results showed lower active, reactive, and apparent power losses of 1.9, 2.6, and 3.3%, respectively, with 50% solar PV penetration in the LV network as the voltage profile of the LV network was significantly improved compared to the base case of no solar. Further, with 50% PV penetration, THDi and THDv at PCC were noted as 10.2 and 5.2%, respectively, which is within the IEEE benchmarks at LV.

Harmonic Analysis of Grid-Connected Solar PV Systems with Nonlinear Household Loads in Low-Voltage Distribution Networks

A new approach for parameters estimation of double and triple diode models of photovoltaic cells based on iterative Lambert W function

A single-diode model for photovoltaic panels in variable environmental conditions: Investigating dust impacts with experimental evaluation

A robust parametrization method of photovoltaic modules for enhancing one-diode model accuracy under varying operating conditions

Finding accurate mathematical model of electrical equivalent circuit of solar photovoltaic (PV) cell is crucial to achieve and improve maximum power point, simulation design and efficiency computations for solar energy system. Due to the nonlinearity of the characteristic of solar PV cell, optimization methods are the best for estimating the electrical model parameters which lead to accurate estimating I-V curve. In this paper, camel behavior search algorithm is proposed as a new method for estimating the five different parameters for single diode model of PV solar module. This is tested on multicrystalline KC 200GT PV module. A measurement data of the module is used to verify and test the consistency of accurately estimating the set of parameters that govern the characteristics I-V relationship of solar cell. The simulation results show that the current-voltage characteristic and power-voltage curve obtained are matching to the measured experimental data set. For performance evaluation, the proposed method is simple, fast in convergence response and has an acceptable accuracy in obtaining the five estimated parameters.

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Parameters estimation of solar photovoltaic module using camel behavior search algorithm

A number of mathematical models are available to model the performance of solar modules under varying operating conditions. Most commonly recognized and used models include (a) the basic three-parameter model, (b) the five-parameter model, and (c) the seven-parameter model. The basic three-parameter model does not incorporate series and shunt resistance for IV curves. The five-parameter model incorporates the effect of series and shunt resistance, and the seven-parameter model further includes the additional effect of temperature and irradiance variation on solar cell parameters. While all these models reasonably predict IV profiles of solar modules at small variations from standard testing conditions (STCs), their performance in modeling the module performance at low irradiances and high temperatures is far from ideal. This work primarily reviews the accuracy of available models for various module technologies not only under STC conditions but also over a wide range of operating conditions. The accuracy of modeled results is quantified (with datasheet results) for 10 crystalline silicon (c-Si) based modules as well as 9 thin film module (TF) samples (commercial modules) at multiple irradiance conditions. The results show that the three-parameter model generally overestimates the power output both for c-Si and TF modules. The five-parameter model predicts TF technology more accurately compared to the other two available models, whereas the seven-parameter model is most accurate for c-Si module modeling under varying operations.

Mirza Qutab Baig

Papers

Evaluation of solar module equivalent models under real operating conditions—A review