Research On Optimization And Application Of Fault Self-healing Scheme For Ji'nan Urban Distribution Network

With the rapid development of economy,the demand for reliability of distribution network is increasing rapidly.The existing self-healing mode of distribution network relying on outgoing switches tripping of substation side and logical coordination of intelligent switches without protection can no longer meet the demand of reliability of power supply.On the basis of existing distri-bution automation,it is of great practical significance to add circuit breaker protection at the line side,reduce the short-term power outage caused by outgoing switch trip during self-healing process in order to further improve the reliability of distribution network power supply.In this thesis,an active self-healing optimization scheme with distribution automation logic and multi-level protection cooperation is formed by centralized intelligent circuit breakers and three-section protections are installed.The cloud platform and edge-aware computing technology based on the distri-bution power internet of things are used for distribution communication and perception.The main contents and achievements are as follows:1)The optimization rules of installation location,protection setting and self-healing schemes of circuit breakers on distribution line side were studied.Line models in different stages of the same distribution line were established.The accident effects and self-healing processes of different stages of models on the main line,branch line and user side were analyzed and compared.It was verified that the self-healing optimization scheme has obvious advantages than the original scheme in reducing the scope of fault influence and users' feeling.2)The realization of self-healing function in the scenarios of communi-cation abnormality,switch/protection rejection,contact cascade mode and live operation were studied to verify that the self-healing optimization scheme meets the application requirements.The implementation of the distribution power internet of things in the scenarios of single-phase disconnection and cable trench patrol were also analyzed.The results showed that the distribution power internet of things technology is an important supplement to the self-healing optimization scheme,which can realize early detection of line side anomalies,and implement active self-healing and defect elimination.3)The application examples and results of the first batch of demonstration projects to implement the self-healing optimization scheme were analyzed.The data validation shows that the reliability index of power supply in the demon-stration area has been significantly improved and has reached the domestic advanced level after the update.In the future,the self-healing optimization scheme can be widely applied in distribution network.