PVSyst Analysis of Nepal 10MW Project
The phenomenon of prices of commodity or technology is coming down as the scale of manufacturing goes up ,the prices of solar have come down to grid tariff which was considered as cheap sources of energy.
In 5 years solar energy prices have fallen down from 20Rs/Kwh to 3.13 Rs/Kwh. The biggest difference in fossil fuel based energy and solar energy is the intermittent nature of renewable energy.
The block diagram consists of an array of panels, inverters and Power conditioning Unit.
The power generates by the several panels is fed to the utility grid. It is necessary to transfer the produced energy to the grid with minimal losses as possible due to less energy yield of the solar PV systems. Hence, it required to minimize these losses by removing the factors that effect the losses produced in PV systems. Shade, dust, snow, rain, temperature are some of the environmental factors that cause losses in a PV system and other losses due to system components such as cables, inverters and transformers.
The table above depicts the annual generation data and main results of a grid-connected system from the previous figure. It shows that the ambient outside temperature over the year is 25.16 oC and energy supplied to the grid is 19939 MW.
Losses due to conductors:
It is necessary to resize the conduit sections so that the voltage drop will be less than>1.5%. It is also necessary to place the generators near to the grid inverter to get the maximal DC voltage so that the panels and inverters can resist the conversion plant performance and reduce resistance losses.
Pwir = Rwir * Isc ^ 2 (1)
compared to nominal power Pnom(array) = Rarray * Isc ^2 (2)
where Rarray = Vmp/Imp at STC(Standard Test Condition)
Vmp and Imp are maximum peak voltage and current.
Rwir = Global wiring resistance of the full system.
Ohmic losses behave in a quadratic way with the array current (Ploss = R* I^2). This means that the ratio diminishes linearly with the output current. Therefore the average wiring losses are much lower during the whole running year.
Module Mismatch Losses
Mismatch losses are due to the interchanging of solar PV panels in series8and8parallel. Hence the selecting of modules becomes quite useful in a complete performance of the SPV plant.
Soiling of PV panels is due to the accumulation of dust and dirt particles from the surroundings.
The module lower edge is one of the critical parts of the PV system. Generally, the module is ground-mounted with a low-level inclination so that soiling at endpoints of the module causes continuously accumulation of water between the glass edges there is a possibility of dirt occurrence.
Module near shadings is due to inter-row distance and also due to tall objects like central room and lightning arrestors. By shading from very tall objects, sufficient spaces are left by conducting a shadow estimating study so as to keep the photovoltaic modules free during generation time.
Power output of a Solar PV module changes with change in direction of sun changes in solar insolation level and with varying temperature. The power vs voltage curve of the module there is a single maximum of power, that is there exists a peak power corresponding to a particular voltage and current. Since the module efficiency is low it is desirable to operate the module at the peak power point so that the maximum power can be delivered to the load under varying temperature and insolation conditions.
The inverter converts power from DC to AC at a certain efficiency, this results in a loss of power during conversion. The efficiency curves are inverter dependent and the inverter used is 2500kW.
Incidence Angle Modifier (IAM) Losses, Module Temperature Losses and Array Losses
The features of a photovoltaic module are determined at STD temperature conditions of 25°C. Including the temperature coefficient of the 390Wp modules selected the module reduces to -0.4% for every °C rise in cell temperature. Module temperature loss is evaluated by simulator by adding the temperature profile of the location as per the metronome database.
Array losses tell about thermal capture loss (LCT) and miscellaneous capture losses (LCM) which occur in a solar PV module and is shown in the V-I Characteristics of array panel which is shown in the below figure.
System Losses from PV Syst