EE-362 Electrical Engineering Department Tasks 2022
Added on 2022-10-14
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CEP PROJECT
Power System Analysis
COURSE CODE: EE-362
GROUP MEMBERS:
Electrical Engineering Department
Batch (2017-2018)
Name Roll No.
Ayesha Muddassir Rizvi EE-17086
Syeda Ariba Shahid EE-17089
Power System Analysis
COURSE CODE: EE-362
GROUP MEMBERS:
Electrical Engineering Department
Batch (2017-2018)
Name Roll No.
Ayesha Muddassir Rizvi EE-17086
Syeda Ariba Shahid EE-17089
Object:
Model 11 (Eleven) bus system given in the book (Power System Dynamics and Stability, by
Prabha Kundur).
Task 1:
Explain its power flow and discuss properly.
Model of 11-Bus System
Fig. 1.
Power Flow Analysis
Real and Reactive Power Flows
Fig. 2.
Model 11 (Eleven) bus system given in the book (Power System Dynamics and Stability, by
Prabha Kundur).
Task 1:
Explain its power flow and discuss properly.
Model of 11-Bus System
Fig. 1.
Power Flow Analysis
Real and Reactive Power Flows
Fig. 2.
Voltage Drops and Current Flows (with power factor)
Fig. 3.
From the schematics above, we can see that there is no voltage drop at the source buses where
generators are connected but the voltage decreases after transformers due to winding losses and
even more so after transmission cables. Also, the overall voltage level on the buses near generator 1
is lower than those near generator 3 due to it having a higher MW rating than all other generators in
the system (850MW > 750MW) and greater load is connected drawing greater current.
Upon inspection of transmission line losses across different transmission cables, we see that it is
highest for the longest cables (110km length of cables 3,4,19 and 25). However, this is not the only
factor for determining magnitude of voltage drop since we also notice that cable 5 has a greater drop
than cable 2 for same length and cable type but since it has more conductors per phase (five as
opposed to only three in cable 2) the overall cable impedance increases. Similarly, it can also be noted
that cable 6 and 1 have a 0.1% difference in voltage drops because cable 6 has a higher gauge value
than cable 1 (750 AWG>500 AWG) and therefore has a higher impedance due to smaller cross-
sectional area, resulting in more voltage loss. Lastly, cables 3 and 19 have a higher drop than cables 4
and 25 due to there being a capacitor of higher Mvar rating (30 Mvar) to compensate for reactive
power loss in the load attached to those buses and hence reduce drop in voltage level near cables 4
and 25.
Fig. 3.
From the schematics above, we can see that there is no voltage drop at the source buses where
generators are connected but the voltage decreases after transformers due to winding losses and
even more so after transmission cables. Also, the overall voltage level on the buses near generator 1
is lower than those near generator 3 due to it having a higher MW rating than all other generators in
the system (850MW > 750MW) and greater load is connected drawing greater current.
Upon inspection of transmission line losses across different transmission cables, we see that it is
highest for the longest cables (110km length of cables 3,4,19 and 25). However, this is not the only
factor for determining magnitude of voltage drop since we also notice that cable 5 has a greater drop
than cable 2 for same length and cable type but since it has more conductors per phase (five as
opposed to only three in cable 2) the overall cable impedance increases. Similarly, it can also be noted
that cable 6 and 1 have a 0.1% difference in voltage drops because cable 6 has a higher gauge value
than cable 1 (750 AWG>500 AWG) and therefore has a higher impedance due to smaller cross-
sectional area, resulting in more voltage loss. Lastly, cables 3 and 19 have a higher drop than cables 4
and 25 due to there being a capacitor of higher Mvar rating (30 Mvar) to compensate for reactive
power loss in the load attached to those buses and hence reduce drop in voltage level near cables 4
and 25.
Generator 1 is the only swing generator in the system and has property to accommodate all system
power losses since the bus it is connected to can be modeled as an infinite source of power
theoretically but practically it has some limits. The remaining three generators are voltage controlled
and can therefore control voltage magnitude of the system with the expense of a change in reactive
power supplied.
When modeling the system, it was evident that cable 2 and 5 were heavily overloaded due to there
being generators connected to both the buses of these cables (Bus 6 and Bus 10). The additional power
entering from the nearby generators at either end of the line and the directly connected ones resulted
in a huge surge of power at both these points (due to summing up). This caused a much higher power
flow and hence greater current flow across these cables above their rated current limit. To resolve the
problem, we had to use bundled conductors of three and five conductors per phase to increase the
cables’ current carrying capacity.
Task 2:
Create overload problem at any portion of the 11-bus system and solve it by at least two appropriate
methods.
Overload Rectification Methods
Below are explained five possible solutions for rectification of overload condition created in the 11-
bus system. We have implemented two of those solutions and attached screenshots from the working
model. The solutions applied to the system were executed on Cable 5, running between bus 9 and 10,
by first converting it into a bundled conductor and then adding a separate conductor parallel to it of
same length and specifications. Therefore, we have only applied the first two solutions to our model
but explained other possible solutions theoretically as well.
power losses since the bus it is connected to can be modeled as an infinite source of power
theoretically but practically it has some limits. The remaining three generators are voltage controlled
and can therefore control voltage magnitude of the system with the expense of a change in reactive
power supplied.
When modeling the system, it was evident that cable 2 and 5 were heavily overloaded due to there
being generators connected to both the buses of these cables (Bus 6 and Bus 10). The additional power
entering from the nearby generators at either end of the line and the directly connected ones resulted
in a huge surge of power at both these points (due to summing up). This caused a much higher power
flow and hence greater current flow across these cables above their rated current limit. To resolve the
problem, we had to use bundled conductors of three and five conductors per phase to increase the
cables’ current carrying capacity.
Task 2:
Create overload problem at any portion of the 11-bus system and solve it by at least two appropriate
methods.
Overload Rectification Methods
Below are explained five possible solutions for rectification of overload condition created in the 11-
bus system. We have implemented two of those solutions and attached screenshots from the working
model. The solutions applied to the system were executed on Cable 5, running between bus 9 and 10,
by first converting it into a bundled conductor and then adding a separate conductor parallel to it of
same length and specifications. Therefore, we have only applied the first two solutions to our model
but explained other possible solutions theoretically as well.
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