Question 1) A 50Hz, 500 MVA, 40kV generator (with transformer) is connected to a 400kV infinite bus bar through an interconnector. The generator has H=205 MJ/MVA, voltage behind transient reactance of 450 kV and is loaded 320 MW. The transfer reactance between generator and bus-bar under various conditions are: Pre-fault: 0.5 pu During fault: 1.5 pu Post fault: 0.75 pu .Calculate the critical clearing angle & critical clearing time. Also detect for clearing angle 40, 50 & 70 is system is stable or not.
Output:
In MATLAB, the problem of calculating the critical clearing angle and critical clearing time for transient stability is solved using the Equal Area Criterion. The Power-Angle Curve is plotted to visualize the system's stability under pre-fault, fault, and post-fault conditions.
The system's stability is evaluated for the following clearing angles using the Power-Angle Curve obtained from MATLAB simulation and analytical calculations:
- Clearing Angle 40°: ✅ Stable.
- Clearing Angle 50°: ✅ Stable.
- Clearing Angle 70°: ❌ Unstable.
Stable Condition:
- Critical Clearing Angle > Clearing Angle (δc)
- Area A1 (accelerating) = Area A2 (decelerating)
- System regains synchronism after fault clearance.
Unstable Condition:
- Clearing Angle (δc) > Critical Clearing Angle (67.17°)
- Area A1 > Area A2
- System loses synchronism and remains unstable.
How to Use This MATLAB Simulation for Transient Stability Analysis
- Download or Open the File with MATLAB.
- Make sure to save the file in your preferred directory or MATLAB workspace.
- Run the Program/Script.
- Enter the Input Data: Enter the values as per the given numerical problem statement.
As per Above Problem Statement:
- Enter internal voltage of machine: 400
- Enter infinite bus voltage: 450
- Enter reactance before fault : 0.5
- Enter reactance during fault : 1.5
- Enter reactance after fault : 0.75
- Enter mechanical power input : 320
- Enter Inertia Constant H (MJ/MVA) : 205
- Enter the clearing angle δ_cl (in degrees) for stability check: 70
Output
引用格式
Prem Manoj Mule (2025). Equal area criteria for transient stability analysis. (https://www.mathworks.com/matlabcentral/fileexchange/180388-equal-area-criteria-for-transient-stability-analysis), MATLAB Central File Exchange. 检索时间: .
MATLAB 版本兼容性
创建方式
R2024b
与 R2019a 及更高版本兼容
平台兼容性
Windows macOS Linux标签
致谢
参考作品: Multimachine Transient Stability Analysis - EE60, equal area criterion
启发作品: Transient stability analysis of single machine infinite bus.
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