Distribution Network Fault Self-healing Technology Based On Relay Protection And Distribution Automation

As an important part of connecting substation and users,distribution network quickly isolates faults when faults occur,and it is especially important to restore power supply in non-faulty areas.When the distribution network fails,using the distribution automation system to complete the automatic location of the fault,isolation and recovery of the non-faulty area power supply is the pursuit of the development of distribution automation.The rapid development of distribution automation is of great significance to improve the quality of users' power supply and realize the efficient and economic operation of the distribution network.In order to realize the failure of the distribution network relay protection and distribution automation to deal with the fault,the three conditions of the secondary protection,three-level protection and intermediate circuit breaker protection of the distribution line are analyzed,a reasonable current setting value and action time limit are set for the branch line,and multi-level cooperation is realized with the outlet circuit breaker,the sectional switch and the demarcation switch.The trunk line relay protection cooperates with the distribution automation to solve the leap-level trip situation and realize the rapid recovery of the power supply in the downstream area of the fault point.The relay protection and distribution automation cooperative fault isolation technology proposed in this paper can solve the phase-to-phase short-circuit fault,the single-phase ground fault of the small current system,and the single-phase ground fault of the small resistance system.The main research contents of this paper are as follows:(1)Analyzed the secondary protection and tertiary protection technology of distribution network,and introduced the power restoration method of centralized control type distribution automation.In order to make the relay protection and distribution automation cooperate to deal with the fault of the distribution network,a synergistic fault isolation technology for relay protection and distribution automation is proposed.(2)Analyze the fault type of the distribution network,and introduce the scheme setting and configuration under different fault types.(3)Focus on the analysis of phase-to-phase short-circuit faults.Non-trunk line short-circuit faults adopt multi-level protection and fault isolation schemes,trunk lines adopt centralized control type power distribution automation scheme;the protection method of small current ground fault and single-phase ground fault of small resistance grounding system is also analyzed.(4)After the fault isolation is studied,the power supply recovery scheme of centralized power distribution automation is adopted.(5)The technical solution of the fault handling scheme proposed in this paper is compared with the existing relay protection configuration scheme,centralized distribution network automation scheme and voltage time feeder automation scheme.The comparison content includes the long-term power outage hours caused by the fault.The number of short-term power outages.(6)ATP simulation model was built to simulate the phase-to-phase short-circuit fault and small-current ground fault,and static simulation experiments were carried out in the Smart Grid Research Center to test the process of inter-station fault,bus fault and outgoing fault,and verify The feasibility of this program.