introduction to solar pv systems-part iii - education
typical deviationWith the typical on-Grid system as shown in Figure 20.1, the off-Grid system as shown in Figure 22.Typically, the solar charging controller also has a DC output that, if any, can power the DC load directly.
There are also a few differences on the sidelines.Grid system as shown in Figure 22.1 About the typical on-Grid system as shown in Figure 20.1.An off-All BoS components that the grid system requires to be openedGrid system required.
Sizing of Off-It is very important to estimate the load accurately.Grid system to make sure it is the right size.There are no shortcuts to doing so;The old must do-fashioned way.
You have to figure out all the loads that will be off-The grid system, and how many hours each grid system will run.This will allow you to accurately estimate your total energy needs.This will help you to adjust the size of the battery.
The inverter must determine the size by considering the maximum load.Using the \"effective sunshine time\" of the place where you want to install the system will help you determine the wattage of the photovoltaic module.The above method implicitly assumes that charge and discharge will be performed every day.
This may not be the case, however.
For example, suppose you have a farmhouse off the net, so it is powered by a farmhouse off the netgrid system.If you only visit this farmhouse on weekends (Saturday and Sunday), this situation requires the battery to be charged within seven days but discharged within two days.On the contrary, there needs to be 3-considering solar street lights-Autonomy of the day, which means that it should work for three days on the cost of the day (or, rather, three nights ).
This situation is completely contrary to the situation of farmhouse;It requires the battery to charge in one day, discharge in three days, in the worst caseIf the sun comes out one day, it doesn\'t come out the next two days.So how do you design off-The grid system depends on what the requirements are and must be determined very carefully and accurately in the caseto-case basis.Types of Off-There are many types of off-1.
Solar battery pack: the size of these systems can vary from small to large.The smaller system powers one or more lights, and may also power two fans.Larger systems power the entire home/farmhouse with several kilowatts of load.
If used for home/office power supply, the solar power supply is also called the solar home lighting system.The output can be DC, and the load must also be DC in this case, such as DC LEDs and DC fans.The mobile charger, or the commonly known \"power group\", is also a good example of a solar battery pack.
In most cases, the power bank is charged by the AC power supply.But in theory, they can also be charged via solar PV modules, which will be very convenient for people who are moving and away from the grid.The output can also be AC, so it can be used to power home/office equipment that requires AC power.
So the output can also be 3-AC phase used to power the motor in the farmhouse.2.Solar Lanterns: these lanterns are very popular.The power grid system has a great effect in rural areas, and the rural areas are the most used places.
However, nothing can prevent a person from using these lanterns in urban areas;They can be very convenient when there is a power outage.3.Solar street lights: these are also popularGrid system, already used in rural and urban areas.Solar street lamps can be independent or centralized.
The independent solar street light consists of Poles, lamps, solar photovoltaic modules, controllers and batteries.A few years ago, the batteries were rather \"bulky\", especially the ones that were once placed in a box attached to the pole.(In India, the batteries are stolen from the box, making the system useless.
I bet you saw these \"useless\" solar street lights somewhere.) However, with the compact Li-ion batteries -We also have these powers on our phones.The street lighting system has also become very compact.
These days the controller and battery are placed in the weatherThe enclosure containing the lamp has a protective rating of 65.If you don\'t know it is, you will find yourself asking, \"where is the battery ?\"?Where is the controller?How does this thing work?Who is controlling it?4.Solar water pumps: While these systems can be used to pump almost any other liquid, they generally refer to solar water pumps.
The use case of the solar water pump is absolutely perfect.When the sun rises and the solar PV module starts to generate enough power, the pump starts to work and pump water from the groundLooks good from the surfaceIn many cases, water enters the field directly, which is called \"flood irrigation \".However, it is recommended that groundwater be pumped and stored in a tank above the ground.
This arrangement would add some additional costs and add a few meters to the \"head\" (height of pumping water), but it is well worth investing because it allows farmers to control when water enters the field;Farmers may not want to water their crops during the day.5.Solar sign-These boards are relatively less popular, but they are a good application of solar photovoltaic technology.Conceptually, they are very similar to independent solar street lights.
These systems are a hybrid.
grid and off-Grid and system;Their job is likeGrid system when grid is available, like off-Grid system is not available.Thus, the battery is also a necessary component of these systems and provides a reliable reference in the event of a power outage.The word \"mixed\" is also used to describe other types of systems.
For example, the system described above-With DG backup and solar-is called DG-solar hybrid.The system with solar and wind energy is solar-Hybrid wind power system.Another example of a hybrid system is the telecom tower, which has DG set backups without exception.
The size of the DG Group is to handle the peak load.So most of the time, they\'re in the sub-This means that the DG Group operates at a lower efficiency.So, now in many telecom towers, what is done is to run the telecom tower and charge it in parallel.
When the battery is fully charged, the DG group is off and the telecom tower is running on the battery.As a result, the DG Group runs less hours at higher efficiency, which is better than running it 24/7 at lower efficiency.These systems are called DG-Even if solar and wind power are not part of the system, so are battery hybrids.
I hope this article will get you off-grid systems.This is the last article in mini-Series of articles on solar photovoltaic system.I will start a new topic from the next article.