TET4180 Electric Power System Stability
An electrical power system consists of many individual elements connected together to form a large, complex system capable of generating, transmitting, distributing and consuming electrical energy over a large geographical area. Because of this interconnection of elements, a large variety of dynamic interactions are possible.
Traditionally electrical machines (generators and loads) were the components that mostly contributed to the dynamic performance. With the penetration of power electronics in the power system other components (shunt/series compensation and load flow controllers) also require a dynamic representation in system studies.
The new controllable components make it possible to increase utilization and to stabilize the system. However due to new generation resources and other new components, the complexity of the studies increases. With the trend of enhanced utilization of the transmission system, a deeper understanding of the models is required.
The increasing number of system disturbances and blackouts in 2003 and later has shown the importance of system dynamic studies and need for a complete overview. These incidents showed that even though margins appeared to be significant, serious blackouts may occur due to elements not accounted for ( "moose test").
Stability is a condition of equilibrium between opposing forces. The mechanism by which interconnected synchronous machines maintain synchronism with one another is through restoring forces. An instable situation may be detected by one or more variables such as generator speed or voltage grows outside the acceptable limits as time is going – the Stability is a condition of equilibrium between opposing forces. The mechanism by which interconnected synchronous machines maintain synchronism with one another is through restoring forces. An instable situation may be detected by one or more variables such as generator speed or voltage grows outside the acceptable limits as time is going – the system is running away.
This course gives you basic understanding of the power system dynamics and how its components interact. It focuses on the physical aspects supported by mathematics, but will also show fundamental principles of system dynamic studies. Interest for power systems overview, electrical machines and control engineering is an advantage.
The course aims to give basic knowledge about the dynamic mechanisms behind angle stability problems in electric power systems, including physical phenomena, modelling issues and simulations.
The course starts with an overview of the power system and the stability problem. Then learning about the components that makes the system, you will able to understand the lessons about electromagnetic and electromechanical phenomena taking place around the synchronous generator. Small system equivalents will be treated analytically to understand the physical behaviour before working on large systems using a computer simulation program (SIMPOW) . Frequency variations and control of system frequency will also be lectured.
- Introduction – course overview
- Power system components
- The power system in steady-state
- Electromagnetic phenomena
- Electromechanical dynamics
- Small and large disturbances
- Frequency variations
- Stability enhancement (overview)
- Advanced power system modelling
- Steady-state stability of multi-machine systems
- Lecture notes
- Written assignments and computer programs