Identification of Power Transformer Currents by Using Random Forest and Boosting Techniques

Abstract

In this research, a differential protection technique for a power transformer is proposed by using random forest and boosting learning machines. The proposed learning machines aim to provide a protection expert system that distinguishes between different transformer status which are normal, inrush, overexcitation, CT saturation, or internal fault. Data for 20 different transformers with 5 operating cases are used in this research. The utilized random forest and boosting techniques are trained using these data. Meanwhile, the proposed models are validated by other measures such as out-of-bag error and confusion matrix. In addition, variable importance analysis that shows signal’s component importance inside a transformer at different instances is provided. According to the result, the proposed random forest model successfully identifies all of the current cases (100% accuracy for the conducted experiment). Meanwhile, it is found that it is less accurate as a conditional monitoring element with accuracy in the range of 97%–98%. On the other hand, the proposed boosting model identifies all of the currents for both cases (100% accuracy for the conducted experiment). In addition to that, a comparison is conducted between the proposed models and other AI-based models. Based on this comparison, the proposed boosting model is the simplest and the most accurate model as compared to other models.

Discrimination between Inrush and Internal Fault Currents in Power Transformers Using Hyperbolic S-Transform

“…Pattern recognition algorithms or machine learning techniques are other methods that have been used in this field. For a power transformer, Khatib and Arar [7] proposed a differential protection technique based on random forest and boosting learning machines. Afrasiabi et al [8] extracted statistical features from the normalized differential current gradient to train the robust soft learning vector quantization (RSLVQ) classifier for developing a new intelligent differential protection scheme.…”