ELEC7310, MODULE I: POWER SYSTEM STABILITY AND DYNAMICS
(SECURITY)
Assignment#4: Static Voltage Stability Analysis
Submission Date: May 2, 2025
The main objective of the assignment is to study the static voltage stability of the WSCC 9 bus test system.
Fig. 1. A single-line diagram of 3-machine WSCC system.
The test system can be found as “d_009” in “tests” folder of PSAT. Note that number assignments to the buses are not as same as in Fig. 1.
Use Power System Analysis Toolbox (PSAT) and MATLAB to produce all the simulation results and hence answer to the following questions.
Questions:
Direct method, repeated power flow
a) Increase the loading level of the system step by step, run a load flow and see whether you are getting convergence or not, report the maximum loading level. For loading “direction,” assume all the loads are increased by the same ratio, and only generator at bus one is allowed to dispatch required additional real power.
b) Plot the voltage against the total load at all the load buses; Find out which load bus having the highest dV/dPTotal at the point closer to divergence?
c) Form. the power flow Jacobian at several loading levels up to the divergence point and plot the following curves.
(i) Smallest Singular value of power flow Jacobian against the total load in the system.
(ii) Minimum eigenvalue of the power flow Jacobian against the total load in the system.
(iii) Condition number of power flow Jacobian against the total load in the system.
(iv) At the divergence point check the reactive power limits of the other two generators (other than swing bus).
Continuation Power Flow Method
a) Run the continuation power flow (use same generation and loading direction as direct method) to obtain the static voltage stability margin of the system. Compare the results obtained in question 1 and comment on the results.
b) Run the continuation power flow and produce PV curve assuming only load at bus 9 is allowed to be increased.
Total mark: 8