Research On Vulnerability Of Time Synchronization System Of New Generation Intelligent Substation Network

At present,there are two kinds of communication network in the intelligent substation,One is based on the Ethernet architecture of Ethernet switch cascade,and the other is based on accessing EPON to the communications network platform.The core exchange part of the new generation intelligent substation is composed of large-capacity packet switch.The access part is based on the physical architecture of EPON which adopts the time-division multiplexing communication mode for high reliability and high real-time communication.time synchronization failure of EPON will affect the station's work,so,the unified time in the intelligent substation is the basic requirement of various protection,control equipment coordination of the power grid,it is also an important basis for analyzing the action behavior of various equipment in the power grid accident,Strong and robust substation time synchronization system is an important guarantee for power system safety production.This paper studies the vulnerability of time synchronization system of the new generation intelligent substation network which based on the time synchronization process.First of all,this paper analyzes the network architecture and main application technologies of substation,introduces synchronous Ethernet technology and PTP technology in terms of time synchronization,adopts SNTP and IEEE1588 to achieve time synchronization program,so that the clock recovery quality can approaches SDH level;Then,the colored Petri nets are used to model the time transfer process of the substation communication network,according to the man-in-the-middle attack mode,simulation is carried out by using OPNET simulation software,through comparing the time delay before and after,the simulation results show that the man-in-the-middle attack can successfully forge the time synchronization between OLT and ONU in EPON communication network and can not be easily found,and then becomes the vulnerability of EPON time synchronization of the substation;Finally,in view of the secrecy of man-in-the-middle attack,based on the parallel network technology of the new generation intelligent substations,two new defense strategies are proposed based on the time information transmission between the master and slave networks: the time synchronization security method based on the return detection and the time synchronization security method based on the difference detection,and the realization process of two kinds of precautionary strategies is introduced in detail.The simulation results show that two kinds of precautionary strategies proposed can effectively solve the man-in-the-middle attack mode and further enhance the security of the EPON time synchronization network of the new intelligent substation.