SOLAR PHOTOVOLTAIC PLANTS

SOLAR PHOTOVOLTAIC PLANTS  

A solar photovoltaic power plant (hereinafter referred to as PV) is designed to provide electricity to household and other devices and is a power plant belonging to the class of renewable energy sources.

The principle of operation of solar power plants is based on the direct conversion of solar radiation into electrical energy with constant voltage, its accumulation and conversion into 380 V AC electricity with a frequency of 50 Hz for use by consumers.

The PV system includes: a photovoltaic panel, a controller, a storage battery, an inverter, as well as connecting wires, junction boxes, terminal blocks and an electrical panel.  

A solar photovoltaic panel is designed to convert solar radiation into electrical energy and charge the battery during daylight hours.

A photovoltaic panel consists of mechanically and electrically interconnected photovoltaic modules. The number of photovoltaic modules included in a photovoltaic panel depends on the required capacity of the PV station.

The required power of the photovoltaic panel is determined by the power consumption of all devices that are supposed to be supplied with electricity from the PV station. The actual electrical power generated by a photovoltaic panel is greater the greater the intensity of solar radiation falling on its beam-receiving surface, and naturally depends on the time of day and year.

The rated (operating) voltage generated by the photovoltaic panel can be 12V, 24V, or 48V.

Photovoltaic System Calculation

The principle of operation of a photovoltaic system is traditional and is as follows: a solar battery charges the batteries during daylight hours. At the same time, the charge controller ensures the correct charging mode of the battery, observing the values of charging voltages for each stage and introducing temperature compensation of voltages. At the same time, the solar array, if necessary, supplies power to daytime loads. Loads operating at night are powered exclusively by the battery. As mentioned above, AC loads are powered through an inverter. It would seem that there are few components in the system, but only their correct selection can ensure reliable operation of loads.

Initially, we determine the capacity of the connected loads and the amount of monthly electricity consumption:  

Based on the known amount of electricity consumed, we will determine the total capacity of the array of solar modules. There are several factors to consider when determining this value:

1. geographical location of the object;

2. Operating period: summer, winter, all year round;  

3. Operating mode: weekend, daily, other scheme;

4. The way solar modules are placed, to get the maximum generation;

5. the presence of relief or landscape details that could block the flow of sunlight to the surface of the solar panels during the day;

6. The possibility or desire to use a movable platform that monitors the position of the sun.

Based on the above, we determine the conditions for choosing a photovoltaic system:8. Solar modules are installed with optimal angles of inclination of solar panels to the horizon. The orientation of the module in space is optimal for obtaining the maximum possible solar energy.

9. Solar panels are not obstructed by terrain, trees, buildings or other elements.

10. There is no monitoring system for the position of the sun. There is no system for positioning solar modules in space.  

   In order for the system to receive the required amount of energy for the entire period of operation, it is necessary to calculate for the worst insolation conditions. If the object is used all year round, then such a month is the month with the minimum amount of light energy. At this time of the year, the insolation is at its lowest, the daylight hours are very short and the clouds are low in most regions of the Republic of Uzbekistan.  

The optimal angle of inclination of solar panels to the horizon differs from region to region and increases in high (more northern) latitudes due to the low angle of the sun. However, there is a simple method for choosing the angle of inclination of solar modules when orienting them to the south. To get the maximum energy in summer, you need to place the panels at an angle 36° less than the geographical latitude of the area; To get the maximum in the winter season, it is necessary to tilt the panels to the horizon at an angle of 15° more than the geographical latitude of the area; To get the maximum for the entire calendar year, the angle of inclination of the solar panels must be equal to the latitude of the terrain. Having chosen the angle of inclination of solar modules, it is necessary to find its value for the required region, season and angle of inclination of the receiving surface in the insolation tables (according to SP 131.13330.2012.