Re: Help on the reactive power flow in matpower.
The power loss (real and reactive) in a branch is given by s_f + s_t, where ...
s_f = v_f * conj(i_f)
s_t = v_t * conj(i_t)
... and i_f and i_t are computed via (3.1) and (3.2) in the manual.
--
Ray Zimmerman
Senior Research Associate
211 Warren Hall, Cornell University, Ithaca, NY 14853
phone: (607) 255-9645
On Apr 25, 2011, at 10:59 AM, z qin wrote:
Hello,
When I calculate the power flow from bus i to bus j, I set
Sij=Pij+1j*Qij=V_i*(I_ij^*). From the real part, I get Pij, which matches the
result of matpower. From the imaginary part, I get Qij, which doesn't match
the result of matpower. So what is wrong with my calculation? Thanks.
Jerry.
On Sun, Apr 24, 2011 at 11:51 PM, jigna pandya jigna_pandya2...@yahoo.com
wrote:
hello,
Reactive power flow balance equation is as follows:
Qgeneration+Qcharging=Qload+Qloss .
(Due to presence of capacitive effect, transmission line injects reactive
power in to the system.)
so Qfrombus+Qtobus=Qloss doesn't hold.
regards
From: z qin zhengr...@gmail.com
To: matpower-l matpowe...@cornell.edu
Sent: Mon, April 25, 2011 8:19:11 AM
Subject: Help on the reactive power flow in matpower.
Hello,
I ran runopf('case9.m') and got the result below. In some branches (1, 4 and
7), Qfrombus+Qtobus=Qloss. However for the rest branches,
Qfrombus+Qtobus=Qloss doesn't hold. Could someone explain for me? I had
thought that
Qij=|Vi|*|Vi|*Bij+|Vi|*|Vj|*(Gij*sin(theta_i-theta_j)-Bij*cos(theta_i-theta_j),
but it seems that it is wrong. Thanks a lot.
Btw, here is how I calculate Pij and Qij. Sij=Pij+1j*Qij=V_i*(I_ij^*), from
the real part, I get Pij, which seems correct; from the imaginary part, I got
Qij, which seems wrong.
Best,
Jerry.
Branch Data |
Brnch From ToFrom Bus Injection To Bus Injection Loss (I^2 * Z)
# BusBusP (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q
(MVAr)
- - -
1 1 4 89.80 12.94-89.80 -9.02 0.000 3.92
2 4 5 35.22 -3.90-35.04-13.87 0.181 0.98
3 5 6-54.96-16.13 55.97-22.18 1.010 4.40
4 3 6 94.19-22.62-94.19 27.28 0.000 4.66
5 6 7 38.22 -5.10-38.07-18.68 0.149 1.26
6 7 8-61.93-16.32 62.21 0.82 0.279 2.36
7 8 2 -134.32 9.32134.32 0.05 0.000 9.36
8 8 9 72.11-10.14-70.72-18.94 1.394 7.01
9 9 4-54.28-31.06 54.58 12.92 0.295 2.51
--
Zhengrui (Jerry) Qin
Computer Science
College of William and Mary
Williamsburg, VA 23185
Re: Help on the reactive power flow in matpower.
Jigna,
Thank you very much. Do you know the formula to calculate the reactive power
flow on a branch if we know the impedance of the branch and the voltage
vector of the two buses? Thanks.
Best,
Jerry
On Sun, Apr 24, 2011 at 11:51 PM, jigna pandya
jigna_pandya2...@yahoo.comwrote:
hello,
Reactive power flow balance equation is as follows:
Qgeneration+Qcharging=Qload+Qloss .
(Due to presence of capacitive effect, transmission line injects reactive
power in to the system.)
so Qfrombus+Qtobus=Qloss doesn't hold.
regards
--
*From:* z qin zhengr...@gmail.com
*To:* matpower-l matpowe...@cornell.edu
*Sent:* Mon, April 25, 2011 8:19:11 AM
*Subject:* Help on the reactive power flow in matpower.
Hello,
I ran runopf('case9.m') and got the result below. In some branches (1, 4
and 7), Qfrombus+Qtobus=Qloss. However for the rest branches,
Qfrombus+Qtobus=Qloss doesn't hold. Could someone explain for me? I had
thought that
Qij=|Vi|*|Vi|*Bij+|Vi|*|Vj|*(Gij*sin(theta_i-theta_j)-Bij*cos(theta_i-theta_j),
but it seems that it is wrong. Thanks a lot.
Btw, here is how I calculate Pij and Qij. Sij=Pij+1j*Qij=V_i*(I_ij^*), from
the real part, I get Pij, which seems correct; from the imaginary part, I
got Qij, which seems wrong.
Best,
Jerry.
Branch Data |
Brnch From ToFrom Bus Injection To Bus Injection Loss (I^2 *
Z)
# BusBusP (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q
(MVAr)
- - -
1 1 4 89.80 12.94-89.80 -9.02 0.000
3.92
2 4 5 35.22 -3.90-35.04-13.87 0.181
0.98
3 5 6-54.96-16.13 55.97-22.18 1.010
4.40
4 3 6 94.19-22.62-94.19 27.28 0.000
4.66
5 6 7 38.22 -5.10-38.07-18.68 0.149
1.26
6 7 8-61.93-16.32 62.21 0.82 0.279
2.36
7 8 2 -134.32 9.32134.32 0.05 0.000
9.36
8 8 9 72.11-10.14-70.72-18.94 1.394
7.01
9 9 4-54.28-31.06 54.58 12.92 0.295
2.51
--
Zhengrui (Jerry) Qin
Computer Science
College of William and Mary
Williamsburg, VA 23185
Re: Help on the reactive power flow in matpower.
Hello,
When I calculate the power flow from bus i to bus j, I set
Sij=Pij+1j*Qij=V_i*(I_ij^*). From the real part, I get Pij, which matches
the result of matpower. From the imaginary part, I get Qij, which doesn't
match the result of matpower. So what is wrong with my calculation? Thanks.
Jerry.
On Sun, Apr 24, 2011 at 11:51 PM, jigna pandya
jigna_pandya2...@yahoo.comwrote:
hello,
Reactive power flow balance equation is as follows:
Qgeneration+Qcharging=Qload+Qloss .
(Due to presence of capacitive effect, transmission line injects reactive
power in to the system.)
so Qfrombus+Qtobus=Qloss doesn't hold.
regards
--
*From:* z qin zhengr...@gmail.com
*To:* matpower-l matpowe...@cornell.edu
*Sent:* Mon, April 25, 2011 8:19:11 AM
*Subject:* Help on the reactive power flow in matpower.
Hello,
I ran runopf('case9.m') and got the result below. In some branches (1, 4
and 7), Qfrombus+Qtobus=Qloss. However for the rest branches,
Qfrombus+Qtobus=Qloss doesn't hold. Could someone explain for me? I had
thought that
Qij=|Vi|*|Vi|*Bij+|Vi|*|Vj|*(Gij*sin(theta_i-theta_j)-Bij*cos(theta_i-theta_j),
but it seems that it is wrong. Thanks a lot.
Btw, here is how I calculate Pij and Qij. Sij=Pij+1j*Qij=V_i*(I_ij^*), from
the real part, I get Pij, which seems correct; from the imaginary part, I
got Qij, which seems wrong.
Best,
Jerry.
Branch Data |
Brnch From ToFrom Bus Injection To Bus Injection Loss (I^2 *
Z)
# BusBusP (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q
(MVAr)
- - -
1 1 4 89.80 12.94-89.80 -9.02 0.000
3.92
2 4 5 35.22 -3.90-35.04-13.87 0.181
0.98
3 5 6-54.96-16.13 55.97-22.18 1.010
4.40
4 3 6 94.19-22.62-94.19 27.28 0.000
4.66
5 6 7 38.22 -5.10-38.07-18.68 0.149
1.26
6 7 8-61.93-16.32 62.21 0.82 0.279
2.36
7 8 2 -134.32 9.32134.32 0.05 0.000
9.36
8 8 9 72.11-10.14-70.72-18.94 1.394
7.01
9 9 4-54.28-31.06 54.58 12.92 0.295
2.51
--
Zhengrui (Jerry) Qin
Computer Science
College of William and Mary
Williamsburg, VA 23185
Help on the reactive power flow in matpower.
Hello,
I ran runopf('case9.m') and got the result below. In some branches (1, 4
and 7), Qfrombus+Qtobus=Qloss. However for the rest branches,
Qfrombus+Qtobus=Qloss doesn't hold. Could someone explain for me? I had
thought that
Qij=|Vi|*|Vi|*Bij+|Vi|*|Vj|*(Gij*sin(theta_i-theta_j)-Bij*cos(theta_i-theta_j),
but it seems that it is wrong. Thanks a lot.
Btw, here is how I calculate Pij and Qij. Sij=Pij+1j*Qij=V_i*(I_ij^*), from
the real part, I get Pij, which seems correct; from the imaginary part, I
got Qij, which seems wrong.
Best,
Jerry.
Branch Data |
Brnch From ToFrom Bus Injection To Bus Injection Loss (I^2 *
Z)
# BusBusP (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q
(MVAr)
- - -
1 1 4 89.80 12.94-89.80 -9.02 0.000
3.92
2 4 5 35.22 -3.90-35.04-13.87 0.181
0.98
3 5 6-54.96-16.13 55.97-22.18 1.010
4.40
4 3 6 94.19-22.62-94.19 27.28 0.000
4.66
5 6 7 38.22 -5.10-38.07-18.68 0.149
1.26
6 7 8-61.93-16.32 62.21 0.82 0.279
2.36
7 8 2 -134.32 9.32134.32 0.05 0.000
9.36
8 8 9 72.11-10.14-70.72-18.94 1.394
7.01
9 9 4-54.28-31.06 54.58 12.92 0.295
2.51
Re: Help on the reactive power flow in matpower.
hello,
Reactive power flow balance equation is as follows:
Qgeneration+Qcharging=Qload+Qloss .
(Due to presence of capacitive effect, transmission line injects reactive power
in to the system.)
so Qfrombus+Qtobus=Qloss doesn't hold.
regards
From: z qin zhengr...@gmail.com
To: matpower-l matpowe...@cornell.edu
Sent: Mon, April 25, 2011 8:19:11 AM
Subject: Help on the reactive power flow in matpower.
Hello,
I ran runopf('case9.m') and got the result below. In some branches (1, 4 and
7), Qfrombus+Qtobus=Qloss. However for the rest branches,
Qfrombus+Qtobus=Qloss
doesn't hold. Could someone explain for me? I had thought that
Qij=|Vi|*|Vi|*Bij+|Vi|*|Vj|*(Gij*sin(theta_i-theta_j)-Bij*cos(theta_i-theta_j),
but it seems that it is wrong. Thanks a lot.
Btw, here is how I calculate Pij and Qij. Sij=Pij+1j*Qij=V_i*(I_ij^*), from
the
real part, I get Pij, which seems correct; from the imaginary part, I got Qij,
which seems wrong.
Best,
Jerry.
Branch Data |
Brnch From ToFrom Bus Injection To Bus Injection Loss (I^2 * Z)
# BusBusP (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q (MVAr)
- - -
1 1 4 89.80 12.94-89.80 -9.02 0.000 3.92
2 4 5 35.22 -3.90-35.04-13.87 0.181 0.98
3 5 6-54.96-16.13 55.97-22.18 1.010 4.40
4 3 6 94.19-22.62-94.19 27.28 0.000 4.66
5 6 7 38.22 -5.10-38.07-18.68 0.149 1.26
6 7 8-61.93-16.32 62.21 0.82 0.279 2.36
7 8 2 -134.32 9.32134.32 0.05 0.000 9.36
8 8 9 72.11-10.14-70.72-18.94 1.394 7.01
9 9 4-54.28-31.06 54.58 12.92 0.295 2.51
