ELECTRIC POWER SYSTEMS | EIE030 |

**Aim**

The demand for electrical energy is still increasing. To keep the high grade of reliability of electrical distribution and also make it more economic and environmentally friendly, there are many projects going on: Renewable production of electric energy is installed and the international trade is increasing. Increased capacity of the transmission system is achieved by advanced supervision and control instead of the expensive building of new transmission lines. Higher utilization of the power system requires better understanding not only of the function of the separate components, and also of the characteristics of the whole system. The course is meant to give knowledge about systems for production, transmission and distribution of electric energy under normal and abnormal conditions. The power blackout on a national level is used as a thematic example throughout the course.

The course presents the structure and characteristics or the electric power system, which are lectured and studied in classroom and computer excercises and practical tests in two laborations. In industry, computer calculations are used for the analyses of international power systems. This type of calculations are part of the course, as well as calculations by hand, used to be able to understand the computerized calculations.

The course has relevance for an environmentally sustainable development: Electric energy is the most important form of energy for our prosperity. The course teaches how the power system works and can be controlled as effectively as possible and thereby minimize our energy consumption.

*Knowledge and understanding*

For a passing grade the student must

- formulate simple models of an electric power system for computation of load flow and symmetric and asymmetric fault currents
- describe the calculation process of a computer programme for the calculation of load flow
- calculate symmetric and asymmetric fault currents for a simple model of an electric power system
- formulate stability criteria for a simple power system model
- explain the meaning of selectivity for a relay protection system.

*Skills and abilities*

For a passing grade the student must

- evaluate computer calculations of fault currents, stability, and load flow by hand calculations.

*Judgement and approach*

For a passing grade the student must

- show insight into the possibilities and limitations of the electric power system and its role in society.

**Contents**

- Construction and function of key components. Power electronic control and compensation.
- System representation: Single line diagram. Symmetrical components. Per unit normalization. Short-circuit MVA.
- System characteristics during normal operation, short-circuits, asymmetry and resonance. Angle and voltage stability. Computer dynamic simulations and load flow calculations. Control of voltage, frequency, active and reactive power. Relay protection.
- Study visit.

**Literature**

Glover J D, Sarma M: Power System Analysis and Design, 2002, ISBN 0-53495-367-0 (third edition)