Slider Explanations
- V1 & V2: Per-unit voltages on either side of the transmission path (0.01–1.1).
- Z (Pre-Fault): The system/line reactance (in p.u.) before the fault occurs.
- Pmech: The mechanical power (p.u.) supplied by the prime mover.
- Inertia (H): Per-unit inertia constant; higher values mean a heavier rotor (slower acceleration).
- Fault Duration (cycles): How many 60 Hz cycles the fault persists (0–360) before clearing.
- Z-Post-Breaker-Clear: The system/line reactance after the fault is cleared (0.01–1.1).
- Playback Slowdown (Log Scale):
1 = real-time, 10 = 10× slower, 1000 = 1000× slower, etc.
The slider value is interpreted as 10^(slider), up to 10,000× slower.
- Damping (D): A simple damping coefficient representing resistive torques on the rotor.
The Equal Area Criterion
The Equal Area Criterion is a graphical method to assess
whether a synchronous machine remains in synchronism after a disturbance.
We compare:
- Accelerating Region (when
Pmech > Pdel)
- Decelerating Region (when
Pmech < Pdel)
If the area of the “accelerating region” is less than or about equal to
the area of the “decelerating region,” the machine typically remains in
synchronism. Otherwise, it risks losing step and going out of sync.
Plot Descriptions
-
Top (Motor Diagram):
A rotating stator with 3 phases in counterclockwise direction.
A positive rotor angle
(delta > 0) means the rotor leads
the red phase in CCW.
-
Middle (Power Swing Plot):
Plots the sine-based power delivery vs. rotor angle. Green or red shading
shows periods of acceleration or deceleration relative to mechanical power.
-
Bottom (Time vs. Theta, Large):
Display the rotor angle in degrees from time=0 to time=5s.