Research On Real-time And Security Of Communication Network In Smart Substation

The smart grid is the key to achieve the low-carbon development target of the whole society, and the smart substation which is the indispensable platform for transmitting electricity to every household, as an important part of smart grid, is to achieve solar, wind and other new energies accessed to smart grid. Along with the rapid development of smart substation, improvement requirements of real-time and security performance is imminent in the communication network.In paper, one of the critical studies is real-time performance in smart substation. Adopting multiple VLAN division method and priority tag technology is to fulfill performance improvement, and dividing the intelligent electronic devices of the same work nature into the same VLAN is to reduce the data communication across the different VLANs. Using D2-1type substation as the main research object, the paper mainly analyzes the data flows of smart substation which is adopting VLAN division method and priority tag technology. Then the star topological and ring topological structures of smart substation are simulated in OPNET Modeler. The results of simulation show that multiple VLAN division method and priority tag technology are suitable for the two kinds of smart substation. Because of the VLAN division technology, not only network delay and end-to-end delay of smart substation are greatly reduced, but also the broadcast information is inhibited. The SMV message limited in a single VLAN, the load of central switch in star topological structure is reduced. So the real-time performance of communication network in the smart substation is improved.The other critical study is security performance in smart substation. It is the paper that combined SHA-256secure hash algorithm with DES data encryption standard for authentication. First of all, the extension of security authentication codes SAC is fulfilled by SHA-256algorithm, then logical function simulation and timing simulation are simulated in Modelsim software. The result of simulation shows that the algorithm is only computing about several Microsecond, when50MHz clock is used. In other words, the SHA-256algorithm can be used for extension of SAC. Secondly, the SHA-256algorithm is displayed on seven segments LED though FPGA chip. Finally, the extension of message authentication code MAC is fulfilled, which is based on C++to achieve encryption/decryption of DES. Authentication between two intelligent electronic devices is fulfilled though the message extension. There are eight times SHA-256computes and twice DES encryptions and decryptions. And time-consuming is a total of about hundreds of Microseconds, so the impact on real-time performance of smart substation is little. On balance, the technique of message extension in the paper can meet the requirements of IEC61850standard. Authentication can counter data confidentiality, validity, integrity, and other malicious attacks, and improve the security performance of communication network in smart substation.