Power System In Cyber-physical Convergence Fault Propagation Analysis And Protection Strategy

With the continuous improvement of modern information technology,the integration of information network and power grid makes the operation of modern power system more efficient.The monitoring and data exchange depends on the mutual cooperation of information equipment and physical equipment and the transmission of information between each equipment.The development trend of smart grid is to integrate control,communication and computing funct ions into a cyber physical power system.With the integration of information systems and power systems,there are also many potential risks.Major power outages in recent years have shown that the potential security risk of the cyber-physical power system itself is an important factor that induces or promotes the occurrence of chain failures.To this end,this paper investigates the model of the cyber-physical power system,the propagation mechanism of chain faults,and the protection strategy for ch ain faults,mainly doing the following work.First,a fault model of the cyber physical power system is established based on the DC current method and chain faults,and the node conduction matrix and node injection power are used to describe data tampering faults and disconnection faults,and data tampering faults,disconnection faults and compound faults are analyzed in a unified manner.Taking transmission lines as fault objects,the relationship between single-line faults and multi-line faults is introduced.The fault model with the cost required for fault as the objective function and the reliability index for system evaluation are proposed to provide a good theoretical basis for the propagation analysis of faults.Secondly,based on the fault model of cyber physical power system,the propagation process of data tampering fault,broken line fault and compound fault is analyzed.The system topology is determined according to the line overload state,by which the propagation mechanism of various faults in t he system is studied and the fault results are compared and analyzed.The propagation mechanisms of data tampering faults,line breaking faults and compound faults and the impact of faults on the system are quantitatively analyzed by using IEEE9 and IEEE39 standard test cases.Finally,the protection strategy of cyber physical power system is studied from the perspective of transmission line protection,and transmission power complete protection and transmission power partial protection are proposed.Transm ission power complete protection can achieve comprehensive protection for the system,but it is costly and not easy to implement.Therefore,transmission power partial protection is focused on.Transmission power partial protection is used to protect part of the system’s lines to delay the impact of faults on the system or even cut off the propagation path of faults.And compare and analyze the degree of attenuation of different faults in the coverage of transmission power partial protection.As the number of protected lines increases,the impact of faults on the system is improved.The effectiveness of the two types of protection is analyzed with the IEEE9 and IEEE39 standard test cases.The effectiveness of the transmission power partial protection is veri fied by comparing the transmission power partial protection for all cases with no more than three faulted lines in the IEEE39 test system.