Research On Process Method Of Real-time Message On Process Bus In Substation And Its Realization

Substation is one of the most important part of the power system. With the development of novel electronic transducers and intelligent switchgears, the parallel wiring link between the process and the bay level in substation automation system will be replaced by serial optical cable, and this is a technology renovation of the substation automation, it is called as process bus communication in IEC 61850. This dissertation deals with the transmission of the sampled values and trip signals of the process bus, which are the two very demanding kinds of data transfer. The significant achievements are as follows:⑴On the base of in-depth analysis of sampled value and GOOSE model, the internal meaning of the object-oriented modeling defined in this standard is investigated and the sampled value model is constructed and mapped in a specific way. As a result, the intrinsic unified relationship between the abstract model and concrete mapping is revealed, and a favorable theoretic basis is supplied to realize the digital transmission of sampled values and GOOSE message.⑵From the message communication delay composition and the time demand of communication delay of the sampled value message and GOOSE message in IEC 61850, we get that the sampled value message and GOOSE message is real-time message, not like the log and file transmission message. We analyze and point out that the process bus communication is in a real-time message and non real-time message coexist environment, and we point out that IED must have the capability of process both real-time task and non real-time task, then we proposed a structure model that is composed of hard real-time kernel and non real-time kernel in the way of that the non real-time kernel is scheduled by the hard real-time kernel as the lowest priority task and the non real-time kernel is responsible for the non real-time tasks scheduling and management, at last, we analyze the advantages of this structure model.⑶We analyze the work principle of hard real-time kernel-RTAI and its kernel module mechanism, on the base of which we design and program the network adapter chip (RTL8139) driver according to IEEE 802.1q protocol and the protocol stack between the server and client according to the GOOSE message in IEC 61850.⑷We do process level communication experiments on hard real-time kernel RTAI to realize network synchronized switching and network disturbance/fault record retrieval operation, we design the communication model and treatment process and program real-time kernel module code and non real-time task (on the base of general Linux) code.