This project is intended to reproduce 12 stability scenarios for the "All-In-One-System" (AIOS) using Modelica and the OpenIPSL library. The scenarios are:
Simulation time: 10 secs.
Power Flow: 1.
Disturbance: None.
Observations: System equilibrium.
Simulation Notes: Working PF: PF1.
Simulation time: 10 secs.
Power Flow: 1.
Disturbance: Fault applies at t = 1.00 secs. at Bus 3 and clear by opening a circuit between Bus 1 and Bus 3 at t = 1.14 secs.
Observations: Fault lasts for 0.14 secs. The fault is really short and it preserves stability, the system will return to a new equilibrium.
Simulation Notes: Working PF: PF1.
Simulation time: 10 secs.
Power Flow: 1.
Disturbance: Same fault ast #1, however, fault now lasts for t = 0.15 secs.
Disturbance Changes: Change time from t = 1.14 secs. to 1.15 secs. in two places.
Observations: The fault is too long now, the generator will loose synchronism. This is an example of transient (angle) instability.
Simulation Notes: Working PF: PF1. Line open: 1.14 secs. Fault: 1.15 secs. Tolerance: 0.01. Intervals: 500.
Simulation time: 15 secs.
Power Flow: 2.
Disturbance: Sever disturbance is consideres, two circuits are tripped between Bus 1 and Bus 3 at t = 1.00 secs.
Observations: The generator and load are now "islanded". The power consumed by the load is P = 400 MW while the generator capacity is P = 450 MW. The governor is able to restore the frequency close to its nominal value, allowing operation of the island to continue.
Simulation time: 10 secs.
Power Flow: 3.
Disturbance: Same distrubance as #4, however, now the power consumed by the load is P = 500 MW.
Observations: The power demanded by the load, the generator cannot provide. The frequency decay cannot be stopped. This shows a case of frequenc instability.
Simulation time: 10 secs.
Power Flow: 4.
Disturbance: A severe disturbance is considered, this consists of tirpping the generator as well as one circuit betwen Bus 1 and Bus 3 at t = 1.00 secs.
Observations: The motor (load at Bus 4), stalls and the voltages collapse. This shows a case of short-term voltage instability, there is a loss of short-term equilibrium.
Simulation time: 10 secs.
Power Flow: 4.
Disturbance: Fault is applied at t = 1.00 at Bus 3 and cleared by one circuit opening between Bus 1 and Bus 3 at t = 1.15 secs.
Disturbance Changes: Change time from t = 1.14 secs. to 1.15 secs. in two places.
Observations: The fault lasts t - 0.12 secs. The fault is short enough to preserve stability and the system retursn to a new equilibrium point.
Simulation time: 10 secs.
Power Flow: 4.
Disturbance: Same fault is applied at #7. Now, the fault lasts for t = 0.16 secs.
Disturbance Changes: Change time from t = 1.14 secs. to 1.15 secs. in two places.
Observations: The fault lasts too long and the motor (load at Bus 4) stalls, and causes voltage collapse. This shows a case of short-term instability. This is due to a lack of attraction towards post disturbance short-term equilibrium.
Simulation time: 60 secs.
Power Flow: 5.
Disturbance: Once circuit between Bus 1 and Bus 3 is tripped at t = 1.00 secs.
Observations: The automatic tap changer restores the voltage at the load us within the deadband. This happens withing 2 steps and the system response is stable.
Simulation time: 250 secs.
Power Flow: 6.
Disturbance: Same fault as #9, however, the disturbance has a higher load.
Observations: The overexcitation limiter of the generator is triggered and the generator voltage is no longer controlled at t = 60 secs. From there on, the automatic tap changer tries to restore the voltage at the load bus but without success.
The voltage decreases monotonically. A case of long-term voltage instability (by loss of long-term equilibrium). The short-
term dynamics remains stable. The system degradation stops when the tap changer reaches its limit.
Simulation time: 180 secs.
Power Flow: 7.
Disturbance: Same disturbance as #10.
Observations: However, the long-term voltage instability triggers and instability of the hsort-term dynamis in the form of a loss of synchronism of the generator.
Simulation time: 70 secs.
Power Flow: 8.
Disturbance: Same disturbance as #11.
Observations: However, the instability of the short-term dynamics takes on the form of both motor stalling and loss of synchronism.
This work comes from examples first presented in a MatLab Simulink model created and presented by T. Van Cutsem.