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An enhanced protection scheme for power transformers integrating alpha plane analysis
Ahmed S Sayed1, Ehab M Nabil2, Almoataz Y Abdelaziz1,3
1Electrical Power and Machines Department, Faculty of Engineering, Ain Shams University, Cairo, 11517, Egypt.
Scientific Reports
|March 14, 2025
Summary
This study enhances transformer protection using the alpha plane (AP) concept, improving reliability against faults. The new method offers better sensitivity and faster tripping than traditional percentage differential (PD) protection.
Area of Science:
- Electrical Engineering
- Power Systems Engineering
Background:
- Power transformers are crucial for electric power systems, requiring reliable protection.
- Conventional percentage differential (PD) protection faces challenges like current transformer (CT) saturation and detecting certain faults.
Purpose of the Study:
- To propose an enhanced transformer protection scheme by integrating the alpha plane (AP) concept.
- To improve the sensitivity, stability, and speed of transformer differential protection.
Main Methods:
- Redefining AP restraint and operating zones based on transformer current behavior.
- Developing a novel algorithm for computing the alpha-plane complex ratio.
- Evaluating the proposed scheme and PD approach using MATLAB/SIMULINK and experimental tests.
Main Results:
- The proposed AP-based scheme shows higher sensitivity to high impedance ground faults.
- It maintains stability during CT saturation under external faults.
- The scheme provides faster tripping times compared to the traditional PD method.
Conclusions:
- The integrated AP concept offers a robust solution for transformer protection.
- This enhanced scheme overcomes limitations of conventional PD protection.
- It ensures improved network stability and reliability.
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