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Department of Electrical Engineering

Indian Institute of Technology Patna

Experiment No: 5

Study of Solar Power Plant and its Performance

Objectives:

1. Study of the solar panel and connections for 10KW of plant.

2. To study the performance of solar plant in terms of its efficiency and THD

This experiment is to be performed at STPI where a 10KW of solar plant is installed. The solar

panel is installed on roof of STPI building and the battery bank and Grid conditioning unit is in

the control room near the ground in STPI.

SYSTEM OPERATION

The Single phase Grid Conditioner system (GSC) utilizes a bi-directional inverter to supply

conditioned power to a local load and operates as an on-line UPS. The inverter operates in

parallel with the grid supply, with the power to the local load supplied from the solar input via

the inverter. Any excess renewable energy will be exported into the grid.

In the event that insufficient renewable energy is available to meet the local load the grid will

make up the shortfall. Provided the local load is not greater than the capacity of the grid, battery

charging will automatically occur from the grid to maintain the battery bank at its float voltage.

In the event that the grid voltage or frequency moves out of its operating range, the grid will be

disconnected and the load is supplied directly from the inverter / battery with no interruption to

the power fed to the load. Once the grid comes back into its operating range, the inverter

supplying the load synchronizes to the grid and finally gets connected in parallel with the grid,

with the grid again supplying the active power to the load.

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Objective 1: Study of the solar panel and connections for 10KW of plant.

Procedures:

1. Go to the roof of STPI building and see the details of one solar panel.

2.

Observe the connections for the panels and draw its connection diagram and find howmuch short circuit current it can provide. What is the voltage output at main junction box.

3. Now go to the control room and observe the ratings of a single battery and its connection.

Also calculate the current and voltage ratings of battery connections.

Note: this part of experiment must be finished before 10:00 AM so that the next part of the

experiment can be started by 10:00AM.

Lab Report:

1. Draw a neat diagram showing various connections for the solar panels.

2.

For the systems available calculate the current coming from the solar side for 5 KW ofload of unity power factor connected to the power conditioning system if solar is

available in full capacity. If solar capacity is reduced to handle only 2 KW of load then

what would be the current provided by the grid supply.

3. Explain the working of the solar power plant.

Objective 2: To Study the grid connected power conditioning system and its performance.

This experiment has to be done from 10:00 AM till 12:00 noon. And readings should be taken

after every 10 mins. For this one current probe, one multimeter and one Fluke Power Analyzer

should be acquired.

Note: Since the electrical power to the first floor of the STPI is being supplied through this

system, so care should be taken that system should not be made OFF while doing this

experiment. Apart from this, buttons on the front panel of the power conditioning system

should not be pressed unnecessarily.

Since you will be working with high DC/AC voltage, you should be wearing your shoes

while performing this experiment.

Do not touch any LIVE part with the bear hands that may be fatal. Also take care that the

battery terminals should not be touched with the hands as high current is flowing throughit.

Observe the parameters as demanded by the following table

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S No. Time Renewable

Source

Battery Supply Grid Supply Inverter Output

(to load)

V solar

(V)Isolar

(A)

Vbattery

(V)I battery

(A)Vgrid

(V)_

Igrid

(A)Power(KW)

pf Vin

(V)Iin

(A)Power(KW)

pf

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

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Procedures:

1. Measure the voltage of the solar plant at the DC box in the control room using a

multimeter.

2. Press the following sequence of the buttons on the front panel of the power

conditioning unit to measure the respective parameters associated to it, as mentionedbelow.

a. Press

This will give system overview.

b. Press

This will give Source A summary (which is grid supply). (Positive sign of power

means that power is being taken from the grid and negative sign means, reverse of

it.)

c. Press

This will give Inverter Summary.

d. Press

This will give DC summary. (Positive battery current means that battery is being

charged and negative current means that current is being taken out from it)

3.

System should not be made OFF. But if somehow this situation arrives thenpress and when front panel shows No Fault then press

4. Observe the load current using a current probe and Fluke scope and save the

waveforms in it to analyze its THD.

Lab Report:

1. Calculate the efficiency of the power conditioning unit for the instants the readings have

been observed.

2.

Plot the THD with respect to time and mark the load current at that point.

*Enter

* 3Enter

* 4Enter

* 5Enter

Fault Reset Full Auto