Power quality performance analysis for Nonlinear Loads
In this blog, we will perform a power quality performance analysis for non-linear loads using MATLAB. This experiment involves creating a symbolic diagram, building a Simulink model, and analyzing the total harmonic distortion (THD) of the source current.
Step 1: Create a Folder
Open MATLAB and create a new folder in a convenient location (e.g., Documents/MATLAB).
Copy the folder location.
Step 2: Change MATLAB Directory
Change the MATLAB directory by pasting the copied location.
This ensures that MATLAB looks for and saves files in the correct folder.
Step 3: Open Simulink and Create a Model
Open Simulink and create a new blank model.
Save the model with an appropriate name (e.g., "PowerQualityNonLinearLoads").
Step 4: Build the Simulink Model
In the Simulink Library Browser, navigate to Simscape > Power Systems > Specialized Technology > Fundamental Blocks.
Add a Three-Phase Voltage Source block, Current Measurement block, Voltage Measurement block, and Universal Bridge block to the model.
Step 5: Add Non-Linear Load
Add a diode and series RLC branch to represent the non-linear load.
Connect the diode to the current source and connect the load.
Step 6: Measure Voltage and Current
Add a Scope block to measure the voltage and current.
Connect the Voltage Measurement block to measure source voltage and the Current Measurement block to measure source current.
Step 7: Add Simscape Power GUI Block
To execute the power system block, add a Simscape > Specialized Technology > Fundamental Blocks > Simscape Power GUI block.
Step 8: Simulate the Model
Simulate the model for a specified duration (e.g., 0.4 seconds).
Step 9: Analyze Total Harmonic Distortion (THD)
Open the Simscape Power GUI block to visualize results.
Measure THD using FFT analysis:
Go to Continuous > Simscape > Tools > FFT Analysis.
Configure properties, unlock data to workspace, and set format to structure with time.
Measure THD for both voltage and current.
Step 10: Interpret Results
Check THD values for voltage and current.
THD for voltage should be less than 5% (as per IEEE standards).
If the THD for current is high, it indicates poor power quality due to harmonic distortion.
By following these steps, you have successfully performed a power quality performance analysis for non-linear loads using MATLAB. This experiment helps in understanding the impact of non-linear loads on source current quality and allows for effective power system analysis.