Research On The Approach Of Faulty Line Detection In Small Current Grounding System

The safe and stable operations of electric grids can supply electricity users with continuous electricity and ensure the reliability of electricity supply.However,it's unavoidable that a power failure plunges everything into darkness.So we must find out what has caused a power failure as soon as possible and resolve relevant problems.For instance,single-phase ground faults frequently take place with an indirect grounding system of the low voltage distribution network--small current grounding system.And how to detect faults and shun the worsening of an incident,which may endanger electrical equipment and working stuff,is the pre-requisite to enhancing the reliability of grid power supply.This thesis is targeted at the detection of fault lines with single-phase ground faults in the small current grounding system,trying to further explore reasonable wire selection methods on small current grounding system and design relevant wire selection devices with a view to providing theoretical and technical support for the safe and reliable power supply.lt line selection method based on the zero sequence admittance method,which is based on the theory deduction.The basic principle of line method lays a theoretical foundation for future research.Reasonable and precise detection of fault lines can help eliminate problems when they arise.Based on the zero sequence vector theory on the symmetrical component method,and through the analysis of the neutral-to-ground voltage when single-phase ground faults occur in the neutral non-grounding system and the arc suppression coil grounding system and of the zero sequence current features of wire feed,we have come up with the fault line selection method resting on the zero sequence admittance and use this theory to deduce and introduce wire selection methods and basic principles,laying a theoretical foundation for the follow-up studies.Utilizing the data like actual parameters and variables from the feed-out circuits and distribution transformers of Fushun County Distribution Transformer Station in Liaoning Province and the app MATLAB/Simulink,we have built a simulation model and described the calculation of significant parameters of calculation cases and the procedures about the simulation research.The building of the MATLAB simulation model and our testing of the neutral non-grounding system and the arc suppression coil grounding system help us to put forward the effective and viable ways of wire selection when single-phase ground faults happen with the systems.Effective fault line selection devices guarantee the successful selection of the fault lines.With the effective methods,we have had the soft and hard ware systems redesigned.On one hand,to employ the basic functions of the hardware,we have at length designed and analyzed sample circuit modules,A/D conversion modules,control system modules as well as output display screens and keyboards.On the other hand,considering the analysis of software development needs and prospects of the major functions of the software,we have illustrated the design methods and details about the following items: the use of global variables and arrays of data of the main programs and programs;the interruption of the sample service subroutine;fault handling units and display units.