Research On Accurate Fault Location Of Multi-branch Distribution Network

How to achieve fault location of small current grounding system in distributionnetwork quickly is the problem that electricity sector has been to explore. In reality,isolated neutral or via arc suppression coil grounding is adopted in majority, these methodhave many advantages, but in this kind of system, fault current is very small when signalphase grounding happened, and as the presence of interference and measurement errors, itis hard to make a correct judgment of fault line for the traditional fault location criterion,which increases the difficulty to accurate fault location. Simultaneously, traditionalmanual line patrol position costs numerous manpower and material resources, delays theposition time, and has low efficiency. Researching online position method on the basis ofensuring that quickly and accurately locate the fault is helpful to maintain grid equipmentand improve the reliability of power supply. How to accurately and reliably detect andlocate the fault has become an important research direction in the distributionnetwork of small current grounding system.Firstly, this paper briefly introduces domestic and foreign fault location methods, andanalysis the principle, advantages and disadvantages of various methods, then make adetailed analysis of the distribution characteristics of fault current in distribution networkunder different neutral-point wring, and analysis current flows in different faultline and the factors that affect the fault location. Based on the above, this paper usetraditional zero-sequence current amplitude-comparing bearing method to fault sectionlocation for neutral point ungrounded system, adopt the method of shunting resistancenext to arc suppression coil to increase zero-sequence current in neutral by arc extinctioncoil grounding system. This paper propose a method based on the principle ofzero-sequence current equipartition and modulus transmission time difference to intervalpinpoint. A new correction algorithm is also proposed to overcome the low accuracy intraditional fault location method by travelling wave. This paper carries outsimulation test of the new correction algorithm by using PSCAD, results show that thisnew correction algorithm is helpful to improve accuracy of fault location method bytravelling wave. A large number of PSACD Simulation results show that this method proposed in thispaper is accurate and reliable in judgment to small current grounding fault, andthe new correction algorithm has improved the accuracy of travelling wave method, whichhas good prospects for application and practical value.