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.
2. 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.
3. Understanding the connections on the myGRID
Here is a quick snapshot of the connections between the myGrid and myDAQ:
|Fossil Fuel Level||Analog Output 0 (AO 0)|
|Power Signal Frequency||Analog Output 1 (AO 1)|
|Supply Voltage from Generator||Analog Input 0 (AI 0)|
|Load Voltage at Houses||Analog Input 1 (AI 1)|
|LEDs in Houses||DO2, DO3, DO4|
|Monitor AC Signal Frequency||CTR0|
4. Setting up the system
- 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
- Download the myGrid Evaluation Activity Guide.exe
- Run the executable file.
- The front panel will look like this:
- Click on the Smart Grid Control and Monitoring tab. The front panel will look like this:
- Click the Connect & Test button. The Test tab will be displayed.
- 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.
- 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.
- 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.
- 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.
- 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.
NI miniSystems in Pioneer Release allow users in higher education (university/college) to purchase units so they can “ramp up” on integrating NI miniSystems into courses as soon as they are available. National Instruments collects active feedback from users of NI miniSystems in Pioneer Release to acquire sufficient feedback for suppliers and partners before the next release. NI miniSystems in Pioneer Release are stable but not feature complete and will most likely require the use of custom programming to fully meet customer application needs. For this reason, it is recommended that customers self-qualify to participate in the Pioneer Release by obtaining basic LabVIEW training (LabVIEW Core 1 and 2). Participants have access to standard training discounts that can be viewed at ni.com/training.
During the Pioneer Release of an NI miniSystem, support is provided via emails to firstname.lastname@example.org or by posting to a private NI Discussion Forum. To get access to the Forum for yourself or other customers, please contact National Instruments using the above email address.