| In order to inform the remote users of the state of the power system and realize the remote and mobile supervising the system,we should expand the SCADA system to Internet. It is necessary to add remote supervision system to the existing system.Fist,analyzing the demand of the remote supervision system,we know that the functions of the remote supervision system must have system state display,datagram of network display,event display,YX call and YC call,history report and remote user management. The system also requires usability,real time performance,reliability,data consistency and transportability. According this demand,we propose the design plan to the system. The double vision server is Web server and also is application server. The double vision client uses browser as the client application. The server on the on hand provides code and real time database to client,and the other hand,it also send the datagram it has received from network of supervising center LAN.The design of the remote supervision system mainly solves two questions:the real process of data and reliable data display. With data processed in the local machine and real time network communication,we can get the real process of data. With CORBA middleware technology,we copy the data from the server to the client local machine. The network communication is based on UDP,which needs no building connection between the server and client. So system overhead is very little. The reliability of data display is acquired through the mechanism of counting datagram and retransmission. The counting and retransmission of network datagram is encapsulated in the module of network communication. This is transparent to the SCADA application. All what SCADA application to do is the invocation of the sending datagram and receiving datagram interface.At last,we build a trial system and test the whole remote supervision system. The real time performance and reliability meet requirements.
|
PDF Full Text Request