ELEC 7313 – Renewable Energy Integration
Transmission System – PV System Integration
Read the provided files for this assignment on UQ Blackboard, and based on the data given
(PSSE .sav file, .dyr file, .sld file, and .py automation files), answer the following questions.
The cases provided in the assignment are Case 1 (all power generators are synchronous
generators- SGs), case 2 (one SG at Bus 102 is replaced by one inverter-based renewable
energy source-IBR), and case 3 (2 SGs are replaced by two IBRs at Buses 102 and 206). You
need to submit your assignment reports to Blackboard for marking purposes. You are
encouraged to use the Python automation files as a base to create your case specific Python
automations files for your assignment. Python automation is optional, but if you submit valid
Python automation files for your assignment, you will be rewarded with a maximum of 3
bonus marks (which is on top of the 20 marks for this assignment). (20 marks in total)
1. Activity one: system frequency dynamic analysis (11 marks)
a) Explain the impact of the generator tripping at Bus 101 on the system frequency nadir
() values in all three cases. Plot the frequency response curves together (in one
figure) in a time duration, which can indicate the rate of change of frequency (RoCoF)
of the system in different cases during the tripping event. And also comment on the
results. (4 marks)
b) Considering the governor droop 5% in the .dyr files for all synchronous machines, use
a theoretical approach to calculate the frequency in steady-state conditions after the
SG tripping at Bus 101 for all three cases. Hint: use the rating of the generators existing
in the .sav file for the calculation. Also, the extra mechanical power provided by the
TGOV1 governer model is ∆ ∗ (
1
) ∗ , while in the case of HYGOV model, the
extra power is ∆ ∗ (
1.215
) ∗ as hydro governors are a bit different from
other governors (detailed reasons of the differences are beyond the scope of this
course). (2 marks)
P a g e 2 | 2
c) Monitor and plot the real power outputs (P_elec in MW) of all the generators
(including the tripping generator) in the cases 1-3 (3 figures, 1 figure/case) and
comment on the power provided by inverter-based renewable generators (IBRs)
during the frequency disturbance. Hint: plot the output power of all generators of
each case in one plot for each case. (3 marks)
d) Change the droop coefficients of all synchronous generators from 5% to 3%, and plot
the curves of frequency response (in Hz) of all three cases by tripping the same SG
connected at Bus 101 (in one figure). Write down the conclusion based on the plotted
curves, and the theory learned in the lecture. Hint, the location of the droop
coefficient values of each governor in .dyr file can be obtained by checking the model
library section in PSSE documentation. (2 marks)
2. Activity Two: system strength analysis (9 Marks)
a) Plot the voltage curves (in pu in one figure from 0s to 5s) at Bus 152 for case 1 and
case 3 by applying a solid L-L-G fault (zero fault impedance) at two second at Bus 152
for 100ms in a dynamic simulation. Comment on the plotted curves based on the
theory learned in the lecture. (3 marks)
b) Following the fault introduced in activity 2a, plot the voltage curves (in pu) for the
nearby buses of Bus 152 (Buses 151, 153, 202, and 3004) in cases 1&3 (2 figures, 1
figure/case) and comment on the plotted curves results based on the theory learned
in the lecture. (3 marks)
c) Following this activity 2, sub-question a) & b), monitor and plot the reactive power
response (in MVAr) for both case 1 and case 3 at Buses 102 and 206 (2 figures, 1
figure/case). Compare and comment the reactive power response during the fault
event between the IBR (under the LVRT) and the SG (Exciter control). (3 marks)