—The challenges of modern power systems will inevitably impose increased ancillary service requir... more —The challenges of modern power systems will inevitably impose increased ancillary service requirements to pho-tovoltaic (PV) plants in the future, including operating reserves. Recent studies investigate methods to maintain active power reserves without energy storage in the standard case of uniform illumination. In this paper, this functionality is extended to partial shading conditions, often encountered in PV systems. A new control scheme is proposed that permits operation at a reduced power level, estimating at the same time the shading conditions and maximum available power. This is achieved by applying a least squares curve fitting algorithm on voltage and current measurements, without relying on any irradiance or temperature sensors. To the best of our knowledge, this is the first power reserves control scheme for PV systems under partial shading presented in the literature. The robustness and effectiveness of the proposed method is validated under rapidly changing shading conditions through simulations and experimental tests on a 2 kW PV system prototype. Index Terms—Active power control, maximum power point tracking (MPPT), partial shading, power reserves, photovoltaic (PV) system.
In electric grids with large photovoltaic (PV) integration, the PV system dynamics triggered by i... more In electric grids with large photovoltaic (PV) integration, the PV system dynamics triggered by irradiance variation is an important factor for the power system stability. Although there are models in the literature that describe these dynamics, they are usually formulated as block diagrams or flowcharts and employ implicit equations for the PV generator, thus requiring application-specific software and iterative solution algorithms. Alternatively, to provide a rigorous mathematical formulation, a state-space representation of the PV system dynamics driven by irradiance variation is presented in this paper. This is the first PV dynamic model in entirely state-space form that incorporates the maximum power point tracking (MPPT) function. To this end, the Lambert W function is used to express the PV generator's equations in explicit form. Simulations are performed in MATLAB/Simulink to evaluate and compare the proposed dynamic model over the detailed switching modeling approach in terms of accuracy and computational performance.
Abstract This paper presents a new method for VAr planning under multiple operating scenarios, op... more Abstract This paper presents a new method for VAr planning under multiple operating scenarios, optimizing sizes and locations of new reactive compensation equipment to ensure that both the system voltage profile and voltage stability requirements are met. The ...
—The challenges of modern power systems will inevitably impose increased ancillary service requir... more —The challenges of modern power systems will inevitably impose increased ancillary service requirements to pho-tovoltaic (PV) plants in the future, including operating reserves. Recent studies investigate methods to maintain active power reserves without energy storage in the standard case of uniform illumination. In this paper, this functionality is extended to partial shading conditions, often encountered in PV systems. A new control scheme is proposed that permits operation at a reduced power level, estimating at the same time the shading conditions and maximum available power. This is achieved by applying a least squares curve fitting algorithm on voltage and current measurements, without relying on any irradiance or temperature sensors. To the best of our knowledge, this is the first power reserves control scheme for PV systems under partial shading presented in the literature. The robustness and effectiveness of the proposed method is validated under rapidly changing shading conditions through simulations and experimental tests on a 2 kW PV system prototype. Index Terms—Active power control, maximum power point tracking (MPPT), partial shading, power reserves, photovoltaic (PV) system.
In electric grids with large photovoltaic (PV) integration, the PV system dynamics triggered by i... more In electric grids with large photovoltaic (PV) integration, the PV system dynamics triggered by irradiance variation is an important factor for the power system stability. Although there are models in the literature that describe these dynamics, they are usually formulated as block diagrams or flowcharts and employ implicit equations for the PV generator, thus requiring application-specific software and iterative solution algorithms. Alternatively, to provide a rigorous mathematical formulation, a state-space representation of the PV system dynamics driven by irradiance variation is presented in this paper. This is the first PV dynamic model in entirely state-space form that incorporates the maximum power point tracking (MPPT) function. To this end, the Lambert W function is used to express the PV generator's equations in explicit form. Simulations are performed in MATLAB/Simulink to evaluate and compare the proposed dynamic model over the detailed switching modeling approach in terms of accuracy and computational performance.
Abstract This paper presents a new method for VAr planning under multiple operating scenarios, op... more Abstract This paper presents a new method for VAr planning under multiple operating scenarios, optimizing sizes and locations of new reactive compensation equipment to ensure that both the system voltage profile and voltage stability requirements are met. The ...
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