| Power system online monitoring and assessment is of great importance with the realization and gradual strengthening of national grid interconnecting in China. It has been regarded that power system safety, reliability, stability can be significantly improved by using the technique of online monitoring and assessment, which can timely analysis the power grid operation, find the critical problems, and provide optimal preventive or emergence controls. So researches on'Power System Online Security Assessment'have been paid more attention especially with considering the influence of power system deregulation and DER integration nowadays.Aim of this thesis is to find a good way to design and develop the program of power system online security assessment. A platform+plugin structure is given after deeply comparison. It is then successfully applied to the design and develop a power system online assessment and visualization system used in Tianjin municipality. In the system, graphic platform serves as the system container, and analysis modules are designed to be separate plug-ins, which provide some special services and are embedded into the platform. Work of this thesis is mainly to design, program, code and integrate a plug-in named power flow data into the whole system. Main work is as follows:Firstly, functional and detail designing for the power flow data plug-in is given according to user's requirements.Secondly, a common interface between the main platform and plug-in is defined and realized. All communications between platform and plug-in are carried out through the interface, including the registration, loading and unloading of the plug-in.Thirdly, all functions of the plug-in are coded and completed by using the language of Visual C++. The functions include but not limit to: power flow data preparing, updating power flow data to graphic platform, managing data of electrical devices for drawing, showing device's properties, managing connection of devices, coloring painting, managing the data of system cut sets, et al. It also provides basic power flow data to other plug-ins that have registered to the system.Fourthly, the given plug-in is coded and released in the form of dynamic link library (DLL). It has been successfully integrated into the online assessment and visualization system for Tianjin power system.It is revealed that the structure of'platform + plug-in'can make the online system more flexible, stable and easier to maintain. |
