Studying the operation of a Power Grid
Overview:
In this tutorial we will utilize the myGrid miniSystem with NI myDAQ and LabVIEW to demonstrate
energy monitoring, energy conservation, and the concept of the smart grid. The system models a
traditional power source through a motor representing fossil fuels and a renewable power source using a
solar panel. Students can directly explore fundamental concepts such as how power is generated,
transmitted, and distributed in a residential setting across three houses. By the end of this tutorial, you
will be able to:
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Control the myGrid using an activity guide interface
Control the fossil fuel generation and monitor the solar energy input
See the affect of switching transformers in and out of the system
Observe the myGrid operating in automatic control as a smart grid
Download the example program and follow the tutorial to replicate the experiment in your lab or dorm
Background
The need to conserve non-renewable resources is reality all over the world and most power utility
providers are incorporating renewable energy sources into their grid systems. As a result, power systems
are undergoing a dramatic change. A typical power grid receives power from a variety of sources and
distributes that power to different consumers. The grid should operate in a smart manner by balancing
the use of renewable and non-renewable power sources while also working to achieve maximum
efficiency. It is often challenging for an electric utility to provide reliable, quality power under the wide
variety of operating conditions that include interruptions due to equipment failures, power disturbances,
and outages.
An important component of smart grid operation is the consistent monitoring the grid to measure the
power available to the consumer and compensating for the demand in real time. The myGrid gives
students the ability to interact with a small scale real-time smart grid system models the technologies
that actual utility companies use to monitor their power grid systems.
What is myGrid
The myGrid by Elenco is a small scale replication of an actual power grid systems to model power
generation and distribution for NI myDAQ. Actual working scaled-down models of the power sources are
included in the myGrid. A DC voltage is used to represent fossil fuels. The sum of DC currents created
from these DC voltages are used to produce an infrared beam that is connected to circuits producing an
AC voltage proportional to the total energy input. A power amplifier produces a low amplitude 60 Hz
signal to emulate the AC power required to drive a smart distribution grid. A transformer steps up the
voltage that is transmitted over wires with resistance added to emulate a long distance. A second
transformer returns the voltage to the required value for consumer consumption on the receiving end of
the high voltage line.
Houses with internal loads are switched on and off to emulate the consumption of the AC power after
transmission. Using a software front panel, AC voltage measurements monitor the supply and demand of
the grid.
The fossil fuel level can be controlled manually by the user or automatically by the software. In automatic
mode, if the load voltage falls below a low line value the power station automatically increases the
voltage being generated to satisfy the load conditions. This is accomplished by increasing the current
through an infrared diode that is mixing the different energy sources. If the frequency deviates from the
desired set value, the power station automatically makes an adjustment on the DC motor that is attached
to the device that is breaking the infrared beam.
Understanding the connections on the myGRID
Here is a quick snapshot of the connections between the myGrid and myDAQ:
myGrid
myDAQ connection
Fossil Fuel Level
Power Signal Frequency
Supply Voltage from Generator
Load Voltage at Houses
LEDs in Houses
Monitor AC Signal Frequency
Analog Output 0 (AO 0)
Analog Output 1 (AO 1)
Analog Input 0 (AI 0)
Analog Input 1 (AI 1)
DO2, DO3, DO4
CTR 0
Setting up the system
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Place the myGrid platform on a flat surface in a location with ample ambient light.
Set the Transformer switch to ON and the Source switch to Solar.
Ensure that the myDAQ is connected to the computer and active with your computer.
You are now ready to measure and control your myGrid.
Controlling and Monitoring the myGrid
1. Download the myGrid Evaluation Activity Guide.exe
2. Run the executable file.
3. The front panel will look like this:
4. Click on the Smart Grid Control and Monitoring tab. The front panel will look like this:
5. Click the Connect & Test button. The Test tab will be displayed.
6. On the Test tab, you will see the AC power signal shown on the graph and the meter will display
the AC frequency. Follow the instructions for calibrating your myGrid. After the calibration
process is completed, click on the Run tab to start experimenting with the myGrid.
7. Manual Mode:
The program will be in manual control mode by default. In this mode you can directly control the
level of fossil fuel input by changing the value of the slider on the left. Explore the operation of the
grid by changing the fossil fuel level control while changing the amount of solar input by blocking
the light partially or completely. Try turning on the LEDs in the houses and observe the amount of
fossil fuel and/or solar input that is required for the LEDs to illuminate. The graph will show the
distribution of solar vs. fossil fuel.
8. Transformer Test
Set all three houses to on and set the fossil fuel level to a level between 75% and 80%. Notice the
load voltage level and the brightness of the houses. Switch the Transformer switch on the myGrid
to OFF. What happens to the LED brightness and the Load Voltage value?
Challenge: Explain the reason for the changes you observe.
9. Automatic Mode:
Switch the control mode to Automatic. Explore the operation of the myGrid in automatic mode.
You will not be able to control the fossil level directly, but observe how it changes as you turn
houses on and off while shading and unshading the solar cell. The fossil fuel level will
automatically adjust to keep the load voltage in the correct range.
10. Close the myGrid Evaluation Activity Guide.exe when you are finished.
Challenge: Set the control Mode to Automatic and light one house. Watch the Cumulative Power
Consumed indicator to see how much power is consumed during 6 “myGrid hours.” (This is 6 minutes of
real time.) Calculate the monthly use that amount reprsents. Does your calculated amount represent a
realistic use for a real household? Research the energy use of common household items and create an
outline showing what household use could have consumed the amount of power you measured.