Application And Research Of OPC Technology In Substation Monitoring System

Substation monitoring system is an important technical measure to ensure that the operation of substation safely and stably. It can reduce operation and maintenance costs, improve economic efficiency and provide users with high quality electrical energy. Currently, substation monitoring system generally have multiple communication protocols coexist and limitations of lacking unified interfaces. How to use an efficient and economical way to sharing data in substation monitoring system is an important research direction.OPC (Object Linking and Embedding for Process Control) technology is a standard set of interfaces, properties and methods based on Microsoft’s COM (Component Object Model) and DCOM (Distributed Component Object Model) technology. The significance of this paper apply OPC technology to substation monitoring system is provides a unified, open and efficient data communication mechanism in order to achieve internal real-time data exchange and real-time transfer of remote information. As a result, communication protocols can be simplified, system costs can be reduced, and system integration and scalability can be improved greatly.Firstly, research background and significance of this project are introduced in this paper. Based on the analysis of functional requirements, this paper points out the research status and problems of current substation monitoring system. Then, a brief introduction to OPC technology is given, and the advantages of using OPC technology are analyzed in detail.Integral structure and data communications of the substation monitoring system are discussed in this paper, and the modular hierarchical structure design of substation monitoring software integrated with OPC technology is given. By adopting a unified communication way between OPC client and OPC server, solving the problem of different communication protocols conversion.OPC Server is a data provider, it gets Real-time data of specified data source by internal data acquisition module, and provides interfaces for OPC client. According to project requirements and available resources, this paper developes OPC server using WTL (Windows Template Library) provided by Microsoft Visual C++6.0as a development tool. The idea of modularization is used in integral structure design of OPC server. Data acquisition sub-module is implemented in the form of DLL (Dynamic-Link Library), which user-friendly for secondary development.By configuration module, OPC client gets the name of server it wants to access and the item information it wants to connect, these informations are stored in disk files as persistent objects. Communications between OPC client and OPC server use COM connection point mode through OPC interface, and subscription-based access to on-site data is achieved. The data collected by client is saved to real-time database through database interfaces, alarm status judgment and appropriate treatment is also provided. In addition, multi-threaded design mechanism is introduced in OPC client to realize the connection of one client to multiple servers. That ensure the efficiency of data exchange and achieve the optimization of structure and performance.An instance of using OPC technology in substation monitoring system to achieve master-slave hot standby is given in this paper, and an overall application using OPC technology in substation monitoring system is proposed. By means of testing and analyzing of data communication performance, the results show that the correctness and usability of this paper’s design implementation, which can achieve efficient data communication between a various subsystems of substation and have a good actual application value. Finally, on the basis of reaserch summary, this paper gives the problems need to research and study in the future.