Influence Of Small Current Grounding Mode On Power System Fault

Small current grounding system is a very popular grounding system at home and abroad.At present,the common small current system is differentiated by grounding method,and the most commonly used grounding method is mainly by resistance grounding,the arc suppression coil grounding and not ground three.At present,China's small current grounding system is mainly used in 3-66 k V power system.This is mainly because the small current grounding system in the event of failure can still maintain a period of normal operation,it is widely used.China's 6 ~ 66 k V distribution network power system mostly belong to the small current grounding system,the general use of neutral point or neutral point by the arc suppression coil grounding work,because of its ground fault,the current flowing through the ground Small,also known as neutral non-effective grounding system.A ground fault is a fault caused by a conductor-to-ground connection or a ground insulation resistance that is less than a specified value.According to the fault statistics of the power system operation department,the single-phase earth fault of the distribution network is the most common in the fault of the distribution network due to the influence of external factors(such as lightning,wind,birds,etc.).The highest incidence is the whole electrical short circuit More than 80% of the fault.When a single-phase ground fault occurs,because it can not constitute a low-impedance short circuit,ground current is very small,so called small current grounding system.Its advantage lies in the occurrence of single-phase ground fault in most cases can automatically arc and restore insulation.When the line of permanent single-phase metal ground fault occurs,the three-phase system line voltage is still symmetrical,size and phase does not change,but the system ground is relatively short capacitance,the ground voltage becomes zero.In order to prevent the other phase in the ground caused by two-phase short circuit or even three-phase circuit,which must limit the exclusion of single-phase failure for a certain period of time.This article first introduces the background and significance of this topic research,summarized the neutral point grounding system research status at home and abroad,this paper expounds the classification and characteristics of neutral point grounding power system.Describe the different features of various fault types and specific power system calculation method of short circuit fault is given.Through the application of Matlab simulation software in power system using the Matlab power simulation toolkit for neutral point not effective grounding power system of short-circuit fault modeling and simulation,and further simulation analysis.Finally,the future development direction of the subject for further analysis.This paper is devoted to solving the problem of reducing the damage to the powersystem when the fault is caused by the small current grounding system.Through in-depth analysis of the causes of system failure,so as to find the source to avoid the occurrence of failure.To this end, the following work is planned: (1) to study the characteristics of various ways of neutral grounding. (2) failure analysis of small current single-phase grounding system. (3) Power system short circuit fault classification and calculation. (4) Simulation analysis of small current grounding system fault.