Research On Distribution Networ Single-Phanse Ground Fault Line Detection Device Based On Power Injection Method

Ground fault in the distribution network, A large proportion of single-phase ground fault, Once a single-phase ground fault occurs, If not promptly treated, Is likely to develop into a two-phase Or multiphase Phase short circuit, It not only affecting consumption, is likely to cause significant economic losses, and even cause severe power outages. Ground fault occurs, It is very necessary to timely identify and deal with the fault line. According to the different grounding method of distribution network of single-phase ground fault, Developed a device based on the injection method, And the test experiment.The study of existing line selection methods for comprehensive research and analysis, For injection method of line selection methods, puts forward a method of low frequency signal injection of line selection, through the calculation and simulation, concluded The lower the frequency of the injected signal line distributed capacitance, the smaller the impact, the line loss of the useful signal is also less, The spread of injected signal can be complete and clear, Thereby improving the accuracy of the line selection.In the hardware implementation of this method, there are two difficulties, first need to deal with complex data, easily lead to slow system response. The second is injected special frequency signal is susceptible to interference. The study uses a distributed architecture, a plurality of DSP work at the same time, has reduced thedata calculation of a single DSP, extended data storage space, avoided Single DSP lockup cause the system to not work, Effectively guarantee system stable and reliable operation. For difficulties of injected signal susceptible to interference, Designed a better acuity fixed detectors, By the induction coil and the narrow-band high Q bandpass filter circuit. Induction coil in line arrangement structure design. On the test circuits are sensitive, And reduces the interference for other lines, High sensitivity, Based on different quantity a variety of combination test of induction coil, Draw four measured circuit composed of induction coil in series surrounded schemes achieve best effect, The narrow-band high Q bandpass filter, Completely stuck off power frequency, Band narrower allows only18by hz signal, And has carried on the signal amplification, Effectively ruled out the interference of power frequency and other frequency signal, To solve the disturbance injection method of line selection effect.The system uses high-performance digital signal processing chip TMS320F28335. The hardware consists of two parts of the master control and the fixed detector, including a low frequency signal generator, DSP peripheral circuit, Current detection, Multi-machine communication, LCD module, Keyboard circuit, the narrow-band high Q bandpass filter, The induction coil, etc.