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In order to solve the problem of short-circuit current exceeding the standard in the development of 500kV power grid, a new current limiting device based on high coupled split reactor and parallel circuit breaker is adopted, which can realize the function of equalizing the current of circuit breaker in steady-state operation and limiting current of circuit breaker in transient fault. Due to the introduction of an additional circuit breaker and a high coupling reactor in the current limiting device, there is a large transient voltage in the break of the circuit breaker and in the coupling coil when the fault occurs. In this paper, the overvoltage distribution in the new current limiting device is studied. Firstly, the basic structure of HCSR and the topological structure of main circuit are introduced, and the calculation formulas of coupling reactor and distributed capacitance are deduced. Then, the steady-state current sharing and transient current limiting processes of the parallel circuit breakers are described, and the technical effects of the current sharing process are analyzed and deduced. Last, this paper focuses on the analysis of the operation circuit in the current limiting process, and makes a theoretical analysis and a brief derivation of the current and overvoltage in the breaking process of two circuit breakers with different actions.

Chin contour is an important facial feature to build a 3D morphable model, the core step of which is to establish feature points correspondence between each face in the training set and the reference face. In this paper, robust face detection is implemented firstly using probabilistic method. A probability of detection is obtained for each image of different position and at several scales and poses. Then, the chin contours are extracted accurately using the active shape model (ASM), which depends on the parameters obtained from the face detection. From frontal (0°) to profile (90°) faces that are equally divided into 10 parts, we train 10 flexible models. Then, different flexible models are used to extract the face chin contour according to the corresponding face pose. Experimental results show that the proposed approach can extract the chin contours of different people across different poses with good accuracy.