Model-Based Power Transformer Protection Using Interactive Multiple Model Algorithm

In a centralized protection and control substation (CPC), all of the measurements of the substation, includes voltages and currents, are available to its centralized high-performance processor. This paper proposes a model-based algorithm for protection of the power transformer in a CPC-based substation. The main difficulty in the use of conventional model-based algorithms lies in modeling of the nonlinear behavior of the transformer core. To tackle this problem, in this paper, multiple linear models are employed to simulate the nonlinearity of the magnetic core. At each time instance, the dynamic behavior of the transformer will be followed by one of these linear models and, the proposed algorithm switches between these linear models based on the concept of interactive multiple model (IMM) algorithm. This way, not only the accuracy of the proposed algorithm increases but also the computational burden is significantly reduced compared to conventional model-based algorithms. Therefore, the proposed algorithm has better potential to be implemented in real-world microprocessors. Several experimental tests include turn-to-turn (TTF) and turn-to-ground faults (TGFs) have been employed to reveal the effectiveness of the proposed IMM-based protection algorithm.