AdvancedTopic 76 of 106Electrical Engineering
Power system stability
Ability of generators to remain synchronised after disturbances.
In depth
Stability is the ability of synchronous machines to remain in step after disturbances. Steady-state, transient and voltage stability are distinguished. The equal-area criterion and swing equation (M d²δ/dt²=P_m-P_e) are fundamental tools. Fast fault clearing helps.
Key points
- Critical clearing time
- Power system stabilisers
- Inertia matters
ExampleLosing a large generator causes frequency to drop at a rate set by system inertia.
What is Power system stability?
Ability of generators to remain synchronised after disturbances.
Why is it important to understand power system stability?
Stability ensures that generators stay synchronised after faults and load changes, so the whole grid remains reliable.
What is rotor angle stability?
The ability of generators to remain in synchronism after a disturbance, which depends on the balance between electrical and mechanical power.
What is the equal area criterion?
A graphical method that compares accelerating and decelerating energy areas on the power-angle curve to judge transient stability.
How is Power system stability used in practice?
Typical applications include checking that a generator stays synchronised after a line fault, designing power system stabilisers for a large plant and studying the response of a grid to loss of a large generator.
What should I learn before Power system stability?
Study "Circuit breaker types" first (topic 75 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
What are the key points of Power system stability?
Critical clearing time. Power system stabilisers. Inertia matters.
Can you give an example of Power system stability?
Losing a large generator causes frequency to drop at a rate set by system inertia.
What comes after Power system stability?
The next topic is "Frequency control", which builds directly on this one.
How difficult is Power system stability?
It is classed as Advanced in Electrical Engineering (topic 76 of 106). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Electrical Engineering.