Energy and Power Engineering, 2013, 5, 1421-1424
doi:10.4236/epe.2013.54B269 Published Online July 2013 (http://www.scirp.org/journal/epe)
Date Conversion in BPA and PSS/E Based on China
Southern Power Grid
Kezhen Liu, Qinzhi Wang, Hongchun Shu, Hao Hu
School of Electrical Engineering, Kunming University of Science and Technology, Kunming, China
Received March, 2013
ABSTRACT
This paper undertakes transference of BPA date of the China Southern Power Grid into PSS/E data, covering a com-
parison between DC data and calculated results of power flow which excluded DC data, testing the accuracy of trans-
ference of power flow data, and demonstrating the transference program in data conversion is applicative. The results
show that the two results fundamentally resemble each other, which indicates the transferred data is correct.
Keywords: Flow Calculation; BPA; PSS/E; Date Conversion
1. Introduction
PSS/E software with its powerful function of the simula-
tion calculation has been more and more popular among
domestic research institutions. In the past, to complete
the BPA and PSS/E data transformation, manually change
conversion method is usually used or write the corre-
sponding data conversion program for a particular grid
data [1,2]. This paper takes the southern power grid in
2015 high flow operation mode as an example, carrying
on the conversion between BPA and PSS/E with the data
conversion software, and compares the results of pure
AC and hybrid AC/DC system.
2. The Data Description of the Southern
Power Grid
Southern power grid is a typical large capacity, long dis-
tance, multi-area and interconnected power grid, com-
posed of the five provinces of Guangdong, Guangxi,
Hainan, Guizhou, Yunnan, power grid and the company
directly under it, and connect the power grid of Hong
Kong and Macao by the Guangdong power grid [3-5].
The BPA data of Southern power grid 2015 High flow
operation mode include 1158 generators, 6405 AC nodes,
7636 branches and SanGuang, TianGuang, GuiGuang
double circuits, YunGuang, Nuozhadu DC, Xiluodu DC,
Jinzhong, Lanshang nine HVDC transmission system [6].
In the BPA data of Southern power grid 2015 High
flow operation mode, the generators adopt sub-transient
model, considering the role of excitation system, the
prime motor, governor and power system stabilizer(PSS),
the load adopt static ZIP mode[7-9]. The data contain EA,
EK, EC, FK/FZ, FJ/FZ, FQ/F+, and FV/F+ seven excita-
tion system models, GS+TA, GS+TB, GG, GH four
prime motor and governor models, and SS, SG, SP,
SI/SI+ four PSS models, DC circuit adopt steady-state
model.
For such a giant and complex network, the cost of
manpower and material resources in the writing of BPA
data is enormous. This paper converts it to PSS/E data
with the help of BPA TO PSS/E data conversion soft-
ware, greatly reducing the difficulty of manually filling
original data and its stability data, saving a lot of man-
power and resources, and reduces the risk of input errors.
3. The Flow Calculation Comparison of Pure
AC Network
Correct flow data conversion is the premise and basis for
transient stability analysis, this paper makes flow calcu-
lation of Southern power grid DC circuit using BPA and
PSS/E separately to compare the correctness of the flow
data conversion in the case of pure AC network. Due to
space limitations, these paper only randomly select ten
nodes as shown in Table 1(a), the largest node voltage
amplitude difference is 0.0006, and the maximum phase
difference is 0.06°. The result shows that the converted
PSS/E flow data is very accurate and reliable.
As shown in Table 1(b), the flow calculation results of
BPA and PSS/E are consistent, which proves the BPA
TO PSS/E data conversion software can convert the flow
data of pure AC system.
4. The Comparison of Flow Calculation in
Hybrid AC/DC System
In the case of correct conversion in the pure AC system,

K. Z. LIU ET AL.
1422
then convert the flow data of BPA to PSS/E, with the DC
circuit of the hybrid AC/DC system retained, Table 2(a)
shows randomly selected voltage node contrast. The
largest node voltage amplitude difference is 0.0283, there
are 305 nodes which the maximum voltage amplitude
error are greater than 0.0005, the difference of these
nodes is also about 0.3°, the largest difference of voltage
phase angle is 0.4°.
Table 1. The power flow comparison of ac system.
(a) The comparison of node voltage and phase angle
BPA PSS/E Difference
Node Name Voltage class(kV)Amplitude/(p.u.) Phase angle/(°)Amplitude/(p.u.) Phase angle/(°)Amplitude/(p.u.) Phase angle/(°)
YN01HLZ1 525 1.01 10.5 1.0094 10.46 0.0006 0.04
HUIZHLZ1 525 1.004 -21.7 1.0034 -21.64 0.0006 0.06
JINGANQG 525 1.031 17.9 1.0315 17.89 0.0005 0.01
MAOM0H 525 1.005 -15.8 1.0055 -15.77 0.0005 0.03
CAOP.U.G 525 1.009 13.2 1.0085 13.21 0.0005 0.01
MEIZH0H 525 1.011 -23.6 1.0105 -23.58 0.0005 0.02
DIANXIG 525 1.02 18.5 1.0195 18.54 0.0005 0.04
HUIZXN0P 525 1.001 -26.3 1.0005 -26.26 0.0005 0.04
QUJINGBG 525 1.028 10.8 1.0275 10.76 0.0005 0.04
BAOFENGG 525 1.011 14.4 1.0114 14.41 0.0004 0.01
(b) The comparison of the results in the whole network
Project BPA PSS/E error
Balancing machine active power contribution (MW) 491.63 491.6 -0.006%
Balancing machine reactive power contribution (Mvar) 290.65 290.7 0.017%
active power contribution of the whole network(MW) 187222.9 187222.9 0
Active load of the whole network (MW) 184171.5 184171.5 0
Active lossof the whole network (MW) 3051.479 3051.5 0.0007%
Table 2. The power flow comparison of hybrid ac/dc system.
(a) The comparison of node voltage and phase angle
BPA PSS/E difference
Node Name Voltage
class(kV) Amplitude /(p.u.) Phase angle(°)Amplitude (p.u.)Phase angle/(°)Amplitude/(p.u.) Phase angle(°)
GD01-HLZ 525 1.01 -27.1 0.9727 -26.7 0.0283 0.4
GD01-HLZ 500 0.973 -27 1.0008 -26.83 0.0278 0.17
HUIZHOU7 525 1.006 -21.9 1.0074 -21.6 0.0014 0.3
HUIZ-HLZ 525 1.006 -21.9 1.0073 -21.6 0.0013 0.3
HUIZHLZ1 525 1.006 -21.9 1.0073 -21.6 0.0013 0.3
BOLUO0H 525 1.002 -26.2 1.0029 -25.91 0.0009 0.29
HUICH50H 525 0.998 -27.5 0.9988 -27.2 0.0008 0.3
MAOM0H 525 1.005 -15.8 1.0055 -15.57 0.0005 0.23
CAOP.U.G 525 1.009 13.1 1.0085 13.4 0.0005 0.3
MEIZH0H 525 1.011 -23.6 1.0105 -23.34 0.0005 0.26
(b) The comparison of the results in the whole network
Project BPA PSS/E error
Balancing machine active power contribution (MW) 496.15 478.6 3.5%
Balancing machine reactive power contribution (Mvar) 291.07 289.5 0.54%
active power contribution of the whole network (MW) 193234.5 193195.9 0.02%
Active load of the whole network (MW) 188396.1 188397.6 -0.0008%
Active lossof the whole network (MW) 4838.479 4787.2 1.06%

K. Z. LIU ET AL. 1423
The error of node voltage amplitude and phase angle
in pure AC and hybrid AC/DC system calculated by BPA
and PSS/E is shown in Table 3. From the statistical re-
sults can be seen that the node voltage amplitude and
phase angle difference calculated by hybrid AC/DC sys-
tem is significantly larger than the pure AC system.
The comparison of active power and reactive power in
DC system is shown in Table 4. From Table 4(a) can
see the active power loss in PSS/E is less than that in
BPA, This is because PSS/E ignores the power loss of
the inverter, just considering the active loss of the con-
verter transformer and DC circuit, and BPA calculates
the active loss of the DC inverter.
The reactive loss of the rectifier station is shown in
Table 4(b), it tells the results calculated by BPA and
PSS/E is a little different, but the difference of reactive
Table 3. Difference distribution of node voltage amplitude and phase angle.
(a)The error distribution of the voltage amplitude
Pure AC system Hybrid AC/DC system
The Error Of Voltage Amplitude
ΔU(p.u.) Number of nodes Proportion Number of nodes Proportion
ΔU<=0.0001 4424 69.5% 4706 73.5%
0.0001<ΔU<=0.0005 1852 29.1% 1394 21.8%
ΔU>0.0005 89 1.4% 305 4.8%
(b)The error distribution of phase angle
Pure AC system Hybrid AC/DC system
The Error Of Phase Angle
Δδ(°) Number of nodes Proportion Number of nodes Proportion
Δδ<=0.05° 6320 99.3% 128 2.0%
0.05°<Δδ<=0.1° 45 0.7% 0 0
0.1°<Δδ<=0.3° 0 0 4839 75.6%
0.3°<Δδ<=0.5° 0 0 1438 22.4%
Table 4. The loss comparison of active and reactive power.
(a) The comparison of active power loss (unit: MW)
DC System Commutation bus of the rectifier Commutation bus of inverter station BPA PSS/E Error
SanGuang JINZ-HLZ HUIZ-HLZ 180.6 176.92 3.68
TianGuang TSQD-M1 BEIJIAO 116.4 111.62 4.78
GuiGuang1 ANSH-HLZ ZQ-HLZ 166.0 164.02 1.98
GuiGuang2 XREN-HLZ GD-HLZ 206.8 203.28 3.52
YunGuang YN01-HLZ GD01-HLZ 220.6 215.46 5.14
(b) The comparison of reactive power loss (unit: Mvar)
Reactive power loss of rectifier station Reactive power loss of the inverter station
DC System
BPA PSS/E Error BPA PSS/E Error
SanGuang 1568.2 1592.4 -24.2 1613.2 1577.4 35.8
TianGuang 920.8 904.4 16.4 927.2 893.8 33.4
GuiGuang1 1568.4 1559.4 9 1618.6 1587.2 31.4
GuiGuang2 1568.4 1565.8 2.6 1603.4 1568.2 35.2
YunGuang 2780.8 2817.8 -37 2914.4 2743 171.4

K. Z. LIU ET AL.
1424
loss of inverter station is large, it has some reasons as
followed: 1) in the calculation process of PSS/E, the in-
verter station is given the γ angle control, but BPA
adopts the given voltage control; 2) BPA equivalently
calculates each level of the bridge converter transformer.
It is because there is difference between BPA and PSS/E
in calculation method and DC system model, which leads
to the calculation difference about reactive loss in in-
verter station between both of the software.
5. Conclusions
This paper introduces data conversion software for BPA
TO PSS/E, and makes conversion of BPA date of the
China Southern Power Grid into PSS/E data, through the
test of the data between pure AC system and hybrid
AC/DC system, presenting the BPA TO PSS/E software
is feasible. The most important is that it reduces the dif-
ficulty of manually filling original data and its stability
data, saving a lot of manpower and resources, and re-
duces the risk of input errors.
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