Failures and Protection of Electrical Networks

Lectures:
1. Definition and distribution of transient effects, fault and abnormal states.
2. Calculation of short-circuit currents in complex electric systems.
3. Ground fault in isolated networks
4. Ground fault in compensated networks
5. Basic terms of protections, operation of protections. Basic elements of protections, electromechanical, static and digital relays.
6. Line protections. Over-current protections, short-circuit protections, directional over-current protections.
7. Line protections. Distance (impedance) protections.
8. Transformer protections. Differential protections. Frame-leakage protections, Buchholz protection.

Exercise:
1. Introduction, safety training, short circuit analysis
2. Short circuits - calculations of symmetrical short circuit currents according to EN 60909, influence of reactors and AM
3. Short circuits - calculations of asymmetrical short circuit currents according to EN 60909
4. Short circuits - calculation of short circuit ratios using DIgSILENT PowerFactory software
5. Calculation of ground connection ratios, design of compensating reactor
6. Laboratory measurement of short-circuit ratios and fault locator function
7. Design and setting of overcurrent protection of lines
8. Laboratory measurements - safety interlocks and digital protections of the HV substation in the HARD building
9. Design and setting of line distance protections
10. Credit exercise, test

Projects:
Calculation of symmetrical and asymmetrical short-circuit currents - manual
Calculation of symmetrical and asymmetrical short-circuit currents - using software