HYBRID MODELING OF POWER SYSTEMS FOR COORDINATED VOLTAGE CONTROL

Modeling and simulation of increasingly complex power systems is becoming more important for design, implementation and validation of power system on-line management. Current special-purpose tools are generally weak in the sense that they are mostly blockoriented and thus demand a huge amount of manual rewriting to get the equations into explicit input-output state-space form. Moreover, modification and examination of their encapsulated component models is very time-consuming and often practically impossible. Logical controllers as well as thresholds reached by discrete mechanisms introduce discrete events into continuous dynamics of power systems. This paper describes an efficient hybrid framework for modeling and simulation of power systems in the interest of coordinated voltage control and stability analysis using Modelica as a general-purpose object-oriented language. The proposed hybrid framework has been tested on a 12-bus power system. Simulation results show that the interaction between continuous dynamics of the power system and hybrid automata representing the discrete logical controllers and also nonlinear behavior of load dynamics can easily be studied in the proposed framework. On the other hand, the simulator is significantly fast allowing any coordinated control strategy to be effectively verified in real-time as countermeasure to arrest voltage collapse.