# Tutorial 2 : Electrical basics for solar power plant | Heaven Solar

Hello friends! You are welcomed to the second tutorial of the training series of on-grid solar plant I Shubham Mandot, will provide you with the basic electric knowledge So let us begin! Today,in this video, we will disscus Difference between watt and volt The relation between current ,resistance, watt and volt How to read a basic data sheet of a solar panel What is an open circuit and a short circuit. We also will discuss that how your electricity bill is being calculated. How are series and parallel connections of solar panels are done And also we will perform an activity along with it Come lets begin. So let us study the difference between watt and volt. What is watt? Watt is the unit of power. Now you will ask what is power? Assume that you are rolling a ball from one end to another Then, the energy required to roll that ball per for that duration of time is called power.

Now let us discuss about Volt that is voltage. You must have heard the terms voltage, wattage Why? because these are used everywhere in your home appliances. And to understand the working of a solar power plant, these terms are very important. Let us see what is Volt? Volt or Voltage is called the potential difference. let us come back on our example. We provided physical energy to roll a ball from one end to another. Now, if we want to do the same thing with the electrons, then the force applied on the electrons to displace them from one point to another is called potential difference.

That force is called potential difference. Now, let us know their relationship. Power is equal to voltage times current. Friends, do know that this formula is very much important for understanding your plant's working. This, along with one more formula,called the Ohm's law is very important for your understanding your basic electrical working. You must bee seeing a 'current' term over here. What is current? Flow of electrons is called current. Which means that if a current is flowing from any wire then through that wire, electrons are passing. Electrons are negatively charged. It meansthat electrons are negatively charged particles. So if a charged particle is moving from left to right then a current flows from right to left. i.e, in the opposite direction Let us see what is its unit. The unit of current is Ampere This formula is called the Ohm's law. Voltage equals current times resistance You must be knowing what resistance is The ball which we were moving from one end to another experiences a friction.

That is, if we move a car or we slide our hand over the table, even then we feel a frictional force That friction, in electrical terms is known as resistance. The friction that electrons experience while flowing, is called resistance Let us through an example, know what these things are. Suppose that you are having a 100 W light bulb. It's wattage is 100 W and volt is 240 V AC AC, here is an important term. AC is that current which runs all your home appliances. Its importance will be covered in the coming videos. You have seen wattage and volt We can now find the current by the formula P=VI We have P = 100 W V = 240 V So, we can calculate the current. Current comes out to be 0.41667 A So in this way, each of your home appliances will have a wattage and voltage reading. By observing them, you can know how much current it consumes. And this thing would be helpful in our bill calculation As we have seen that the terms wattage and voltage are used everywhere. On every appliance, it may be an A/c or it may be a fan or a tv In the same way, your solar panel too has a rating In solar panels too, wattage and voltage ratings are given.

And that is mentioned in its datasheet So lets see, how does a typical solar panel datasheet looks like This datasheet is of a solar panel which has a maximum solar power rating of 250W As you can see, four parameters are important here those are open circuit voltage, short circuit current, voltage at maximum power generation and current at maximum power. Vmp and Imp defines the condition at which maximum power, that is 250 W, will be obtained from the solar panel The time at which the voltage is around 30.8 V and current is 8.12 A Then we will multiply them to obtain the maximum power which is 250W These things take place at STC condition that is standard test condition Which is briefed below the datasheet. There is a radiation of 1000 W/ meter sq. air mass is of 1.5 and cell temperature should be 25 degree C Standard test conditions have variations with practicality Hence, for that there is a different test condition which is called normal operating conditions In which, the radiance should be 800 W/meter sq. Because of this difference, the reading of open circuit voltage and that of datasheet turns out to be lower.

The reason to that is different test conditions Let us see what open circuit voltage is what is an open circuit Any circuit that is open is known as an open circuit which means negative and positive terminals are disconnected. Let us consider an example of a solar panel. Each one has a positive and a negative terminal. When a positive and negative terminal is connected to a multimeter, then that voltage is open circuit voltage Multi meter is a device that can measure current, voltage, resistance, etc. Let us now see how is our electricity bill calculated? Lets jump to our previous example Where we saw that we used a 100 W bulb Let us assume that the bulb is glowing for 10 hours Then, the energy consumed by the bulb will be 100 W * 10 hrs which is equal to 1000 Wh 1000 Wh is equal to 1 KWh and that too equals 1 unit of electricity In our bills, number of units used means number of KWh of energy used Let us take another example.

Suppose that you have a laptop having a power rating of 60 W and works for 8 hrs, a fan of 75 W and working for 20 hrs And a bulb of 30 W working for 5 hrs let us calculate the electricity bill with these appliances Energy consumed = power rating * number of operating hours This way, the energy consumed can be calculated and can be converted into KWh All the energy consumed by individual appliance is summed up giving us the total energy consumption This amount is then converted into electricity bill Every state has different per unit cost of electricity accordingly. Let us assume that the cost of 1 kWh is 7 Rs for this example In this way, the price for 2.13 kWh will be Rs 14.91 That is around 15 Rs per day consumption This is then multiplied by 30 days of month Which comes out to be Rs 447.3 That means you pay 450 Rs per month for electricity according to this rating Till now we saw what are electrical basics, its terminology We also saw the procedure of calculating our electricity bill Let s now see the connection of solar panel One panel can generate max 250 W power Which is insufficient, so we will have to connect a number of panels These can be connected in two ways : series and parallel Let us see what is series connection A typical solar panel has a positive and a negative terminal This panel has a voltage V1 That means it generates a maximum voltage of V1 amount Two more panels having voltages V2 and V3 are considered.

See their arrangment Now, we will connect them in series Here, positive terminal and negative terminal are connected together of two different solar panels This way, a chain is formed This is called series connection Its significance is that, at the end, the current through each panel will be the same Each panel will allow similar current in the connection And the output voltage will be the sum of thee individual voltage ratings Let us take an example And take the same example with Vmp = 30.80 V and Imp = 8.12 A If we take 2 more similar panels and connect them in series, Then the output will be like this: Output current = 8.12 A and And output voltage = 3*Vmp = 92.4 V Lets discuss parallel connection Consider the same 3 panels Assume the voltage to be V and currents through the panels be I1, I2 and I3 Configuration should be such that the connection will have positive terminals of each are connected together In series, positive terminal of one was connected to the negative of the other But here, it is not so What will happen is There will be a variation in the output The current gets added up and voltage remains the same This will be the major difference If we consider the same example, 30.8 V and 8.12 A Then the output will be like this: current = 3*Imp = 24.36 A and voltage = 30.8 V Now we know what is series parallel connection And also the basics of electronics You also know how your electricity bill is calculated Isn't it ? We will test it by an activity Friends, calculate the monthly bill of your house for these conditions The details are given on your screen.

Refrigerator : 150 W, 24 hrs 3 fans : 75 W , 20 hrs 5 bulbs : 30 W, 5 hrs Suppose the cost per unit of electricity = 5 Rs Comment your answers in the comment box Like, share and subscribe and stay tuned for the next videos Thank you !.