As photovoltaic （PV） capacity in power system increases, the capacity of synchronous generator needs to be reduced relatively. This leads to the lower system inertia and the higher generator reactance, and hence the...As photovoltaic （PV） capacity in power system increases, the capacity of synchronous generator needs to be reduced relatively. This leads to the lower system inertia and the higher generator reactance, and hence the generator transient stability may negatively be affected. In particular, the impact on the transient stability may become more serious when the considerable amounts of PV systems are disconnected simultaneously during voltage sag. In this work, the generator transient stability in the power system with significant PV penetration is assessed by a numerical simulation. In order to assess the impact from various angles, simulation parameters such as levels of PV penetration, variety of power sources （inverter or rotational machine）, and existence of LVRT capability are considered. The simulation is performed by using PSCAD/EMTDC software.展开更多
The impact of large-scale grid-connected PV （photovoltaics） on power system transient stability is discussed in this paper. In response to an increase of PV capacity, the capacity of conventional synchronous generat...The impact of large-scale grid-connected PV （photovoltaics） on power system transient stability is discussed in this paper. In response to an increase of PV capacity, the capacity of conventional synchronous generator needs to be reduced relatively. This leads to the lower system inertia and the higher generator reactance, and hence, the power system transient stability may negatively be affected. In particular, the impact on the transient stability may become more serious when the considerable amounts of PV systems are disconnected simultaneously during voltage sag. In this work, the potential impact of significant PV penetration on the transient stability is assessed by a numerical simulation using PSCAD/EMTDC.展开更多
OPV （Organic photovoltaic） cells represent a compelling candidate for renewable energy by solar energy conversion. In recent years, versatile light-trapping measures via structures have been intensively explored to ...OPV （Organic photovoltaic） cells represent a compelling candidate for renewable energy by solar energy conversion. In recent years, versatile light-trapping measures via structures have been intensively explored to optimize photovoltaic performance. In this work, a unique rubbing technique is demonstrated to create nanoscale grooves on the PEDOT：PSS [poly（3,4-ethylenedioxythiophene）： poly（styrenesulfonate）] surface and the grating-like features are 500 nm wide and 10 nm deep. The PEDOT：PSS film with grooved surface is used as buffer layers for OPV cell devices based on a P3HT：PCBM bulk heterojunction. The patterned surface has a profound effect on carrier mobility, light trapping, and hole collection efficiency, leading to an increase in the short circuit density, filling factor, and power conversion efficiency. These results indicate the feasibility of the rubbing method can be applicable to high-efficiency OPV cells.展开更多
This paper describes relatively simple stochastic model of the total ground irradiance of horizontal surface. For this purpose clearness index is modeled as a stochastic signal. The parameters of clearness index stoch...This paper describes relatively simple stochastic model of the total ground irradiance of horizontal surface. For this purpose clearness index is modeled as a stochastic signal. The parameters of clearness index stochastic signal are chosen to fit values of daily mean insolation for each month for the location of Zagreb, Croatia. Complete model has been done in MATLAB. This model can be used for Monte Carlo simulations of technical solar systems such as photovoltaic systems or solar thermal energy systems.展开更多
文摘As photovoltaic （PV） capacity in power system increases, the capacity of synchronous generator needs to be reduced relatively. This leads to the lower system inertia and the higher generator reactance, and hence the generator transient stability may negatively be affected. In particular, the impact on the transient stability may become more serious when the considerable amounts of PV systems are disconnected simultaneously during voltage sag. In this work, the generator transient stability in the power system with significant PV penetration is assessed by a numerical simulation. In order to assess the impact from various angles, simulation parameters such as levels of PV penetration, variety of power sources （inverter or rotational machine）, and existence of LVRT capability are considered. The simulation is performed by using PSCAD/EMTDC software.
文摘The impact of large-scale grid-connected PV （photovoltaics） on power system transient stability is discussed in this paper. In response to an increase of PV capacity, the capacity of conventional synchronous generator needs to be reduced relatively. This leads to the lower system inertia and the higher generator reactance, and hence, the power system transient stability may negatively be affected. In particular, the impact on the transient stability may become more serious when the considerable amounts of PV systems are disconnected simultaneously during voltage sag. In this work, the potential impact of significant PV penetration on the transient stability is assessed by a numerical simulation using PSCAD/EMTDC.
文摘OPV （Organic photovoltaic） cells represent a compelling candidate for renewable energy by solar energy conversion. In recent years, versatile light-trapping measures via structures have been intensively explored to optimize photovoltaic performance. In this work, a unique rubbing technique is demonstrated to create nanoscale grooves on the PEDOT：PSS [poly（3,4-ethylenedioxythiophene）： poly（styrenesulfonate）] surface and the grating-like features are 500 nm wide and 10 nm deep. The PEDOT：PSS film with grooved surface is used as buffer layers for OPV cell devices based on a P3HT：PCBM bulk heterojunction. The patterned surface has a profound effect on carrier mobility, light trapping, and hole collection efficiency, leading to an increase in the short circuit density, filling factor, and power conversion efficiency. These results indicate the feasibility of the rubbing method can be applicable to high-efficiency OPV cells.
文摘This paper describes relatively simple stochastic model of the total ground irradiance of horizontal surface. For this purpose clearness index is modeled as a stochastic signal. The parameters of clearness index stochastic signal are chosen to fit values of daily mean insolation for each month for the location of Zagreb, Croatia. Complete model has been done in MATLAB. This model can be used for Monte Carlo simulations of technical solar systems such as photovoltaic systems or solar thermal energy systems.
