基于UML和Petri网的电力系统恢复模型

为了描述电力系统恢复过程,提出了基于UML的电力系统恢复过程建模方法,使用类图表示参与电力系统恢复的主要元件的静态特性,使用状态图表示各元件的动态特性。对所建模型进行了仿真和验证,提出了将UML模型转化为赋时Petri网的方法,将UML模型的操作转化为Petri网中的变迁,将UML模型中操作的输入、输出及约束表示为Petri网的库所。以IEEE RTS-96系统验证了所提方法的可行性,该方法易于对电力系统恢复过程进行模型化分析和软件实现。

Model for Power System Restoration Based on UML and Petri Net

The process of Power System Restoration(PSR) contains many asynchronous or synchronous tasks.In order to represent the process of PSR,an approach for Power System Restoration Modeling based on UML is proposed.The class diagram is employed to describe the static characteristic of components involved in PSR,such as generators,buses,lines and loads.State diagram is employed to describe the dynamic characteristic of the components.Operations are defined when the state changes into another state.The operation contains the involved components,the operational constraints and the time needed to fulfill the task.UML is strong as modeling means in software engineering,supplies several different diagrammatic notations for representing the different aspects of a system under development,but lacks simulation and verifiability capabilities.This paper proposes the paring of UML dynamic models with high-level timed Petri nets(HLTPN) to obtain a flexible and customizable means to reason on the dynamic aspects of PSR.In order to simulate and verify the developed model,an algorithm for converting UML to Timed Petri Net is suggested.The operations in UML model are converted into transitions in Petri Net.The inputs,outputs and constraints are converted into places in Petri Net.The token is used to represent the current status of each object.The time characteristic of state diagram is also represent by timed transition in Petri Net.Three time parameters,enable time, holding time and firing time,are defined to represent the detail process when a transition is fired.Several common constraints in PSR are discussed.An example based on IEEE RTS-96 is given to demonstrate the feasibility of the proposed method.The proposed method is suitable for analysis and software realization of PSR model.