31-08-2017, 10:26 AM
A detection network based on fiber optics applicable to the detection of failures in the power system is presented. The proposed scheme is safe and immune to interference. At each monitoring point passive sensors of robust fiber are deployed based on the Bragg grid. They use fast, compact magnetostrictive transducers instead of current or potential transformers to translate the current-induced magnetic field into an optical signal. These sensors can be compensated for by temperature drift and be easily integrated into an optical detection network. A broadband light source in a substation explores the change in reflected optical power in a single frequency band corresponding to the overvoltage in the magnetic field associated with an increased fault current in a certain position. A unique feature of this real-time scheme is that it only requires current information for fault detection on both radial and network systems with various pole structures and line configurations. It can be easily coordinated with other protection devices and is free of any time-current coordination curve. The proposed scheme has been extensively tested by simulations. They confirm that the proposed scheme is capable of detecting failures regardless of type and location. It also works well in the presence of harmonics, high impedance, and sensor malfunction as well as sensor noise.