# Power System Transmission Line Parameter Calculation Using Excel

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Comparing Energetic Simulators
via a Smart Grid Model
István Vokony, Student, IEEE, Bálint Hartmann, Student, IEEE,
Tamás Decsi, and András Dán, Dr., Senior, IEEE

                                                                        program is able to manage two synchronous systems operating
Abstract—There is a need to develop such structures that are         with different frequency. A control simulation was calculated
easier to control and design. They simplify the network in respect       by Power World Power Systems Analysis Software for the
of the control; they are self-sufficient and occasionally they may       steady-state simulations, because ETSV is not well-known
join the great network. The micro grid may be a solution for
software.
these questions. It is essential to set up an appropriate model for
the examination of these self-sufficient islands. But it is not easy         The modelled network is part of the Hungarian
to decide, which simulation software could be the optimal. In the        transmission system. It consists of the 400/120 kV Győr and
following we would like to compare the most known simulators             the 120/20/10 kV Mosonmagyaróvár substations, the overhead
used in the energy engineering.                                          lines connecting them, and the medium voltage network of the
latter substation. This part of the grid includes the following
Index Terms—island operation, simulation software, smart              generators: a large machine at the 400 kV side of Győr (this
grid
serves as the system slack), three 5 MW gas turbines at the
120 kV side of Mosonmagyaróvár, and two wind farms at the
I. INTRODUCTION
120 kV and the 20 kV side if Mosonmagyaróvár. The capacity

T    HE last decades of the 20th century have brought a huge
acceleration into the field of informatics. One result is that
today many simulation software are available, even ones that
of the wind farms is 50 MW.

are specially designed for energetic purpose. These can be
very different concerning structure, complexity or capabilities.
A software well suiting one task may not fit another well. In
present paper part of the transmission network has been
modelled, to perform simple calculations. The aim of this is to
see, how well each software performs. The following four
simulation packages have been used: ETSV, Power World
Simulator (version 14), PSSE (version 31) and PowerFactory
(version 13.1, build 255).
For set-up and examination purposes a network analyzer
software package – developed by the Department of Electric
Power Engineering, TU Budapest – was used. With the help of
calculations), effects of several faults and breaker operations          Fig. 1. Topology of the network (Power World)
state analysis, dynamic simulations were also calculated. The                                 II. SOFTWARE PACKAGES

I. Vokony. is a PhD-student at the Department of Electric Power
A. ETSV [1]
Engineering, Budapest University of Technology and Economics, Budapest      The program was written in FORTRAN program language
(e-mail: vokony.istvan@vet.bme.hu).                                      and it uses strictly defined file formats as inputs. With the help
B. Hartmann is a PhD-student at the Department of Electric Power
Engineering, Budapest University of Technology and Economics, Budapest   of the program, changes of a transient caused by various
(e-mail: hartmann.balint@vet.bme.hu).                                    connections or errors can be followed up on a discretionally
T. Decsi. is a PhD-student at the Department of Electric Power       complex network. The outputs are the values of the time-
Engineering, Budapest University of Technology and Economics, Budapest
(e-mail: decsi.tamas@vet.bme.hu).                                        functions of the observed nodes, concerning about 80
A. Dán, Dr. is a Professor at the Department of Electric Power       quantities. The representation of functions is feasible by using
Engineering, Budapest University of Technology and Economics, Budapest   an application (RVG) running in DOS environment.
(e-mail: dan.andras@vet.bme.hu).
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Discretional number and quality of the parameters can be              entered.
saved as data files; afterwards they can easily and expressively
be processed with the help of a spreadsheet program (e.g. MS-
Excel).
The application experiences of the program are
summarized below:                                                     Fig. 4. Generator parameters
  discretional sized networks can be handled
  short running times, fast algorithms
  practically any kind of network event can be
simulated
  the output data is well arranged, further processing is
easy
  although DOS environment is out-of-date, but secure
and has low capacity requirements
As first step, a model network had to be set up for the time
simulation program. The software uses ‟.txt‟ and ‟.bin‟ file
types. With the help of PE2 text editor program – running
under DOS – two files were created, describing the network.           Fig. 5. Turbine parameters
One of them contains the bus parameters. The following data
can be seen in the file in relation to the individual buses: serial      After the network was completed the simulations could be
number, name, voltage level, power of the connecting                  started, these are explained in detail in section III..
generator and/or consumption, grouping of the separate zones,
etc..
B. Power World [2]
Power World Simulator is an interactive power system
simulation package designed to simulate high voltage power
system operation on a time frame ranging from several
minutes to several days. The software contains a highly
effective power flow analysis package capable of efficiently
solving systems of up to 100 000 buses.
Power World offers several optional add-ons to extend
Simulator's analysis capabilities;
Fig. 2. Nodes of the network                                             Optimal Power Flow: designers have developed a linear
programming based optimal power flow package. Simulator
The other file contains the topology of the network: the           OPF, an optional add-on to the base Simulator package, is
parameters of lines and transformers, including the ohmic,            ideally suited to determining how to mitigate constraints in the
inductive and capacitive parameters as well.                          most economical fashion, and to report the cost of enforcing
line constraints.
OPF Reserves: extends the power of the OPF and SCOPF
tools to modelling of simultaneous energy and ancillary
services reserve markets.
Security Constrained OPF (SCOPF): the Security
Constrained Optimal Power Flow tool, an optional add-on to
the base Simulator package, is an extension to Simulator OPF
used to achieve an economical operation of the system while
considering not only normal operating limits, but also
Fig. 3. Network parameters
violations that would occur during contingencies. The SCOPF
changes the system pre-contingency operating point so that the
With the help of ‟.dat‟ files other parameters can also be        total operating cost is minimized, and at the same time no
set, if the topology of the base-network is finished. The             security limit is violated if contingencies occur.
parameters of the generators in the system have to be defined            Available Transfer Capability (ATC): simulator ATC
in another file; and the types of the turbines as well. In the        allows you to determine the maximum MW transfer possible
latter one, the typical turbine-parameters are included; if none      between two parts of the power system without violating any
of these meets the requirements, a discretional one also can be       limits. This is the same calculation commonly performed by
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system operators or market operators.                               changers, switched-shunts, HVDC lines and SVC-s as. The
PVQV Curve Tool: simulator PVQV helps fill the                   second module is designed for dynamic simulations. It is
industry's need for a user-friendly planning-mode tool for          mainly used for transient stability calculations by MAVIR, but
analyzing voltage stability and security that is flexible, highly   it can be used for long-term stability analysis, e.g. voltage-
graphical, and easy-to-use. This tool was previously known as       stability study. The third module is the Optimal Power Flow
Simulator VAST.                                                     module that is able to calculate minimizing investments,
Simulator Automation Server (SimAuto): Using SimAuto             running costs, etc.
you can launch and control PowerWorld Simulator from                    Starting with version 31, the software has new plotting and
within another application, thus enabling you to access the         documenting interface helps making results easier to read. Fig.
data of a Simulator case, to perform defined Simulator              6. shows the skin of version 31.
functions and other data manipulations, and then to send
results back to your original application, to a Simulator
auxiliary file, or to a Microsoft® Excel spreadsheet. The
Simulator Automation Server acts as a COM Object, which
can be accessed from various Windows-based programming
languages that support COM compatibility. Examples of
programming tools with COM compatibility are Borland®
Delphi, Microsoft® Visual C++, and Microsoft® Visual
Basic, just to name a few.
Transmission Line Parameter Calculator (TransLineCalc):
it is a tool designed to compute the most important
characteristic line parameters given the type of conductor and
the tower configuration of a three-phase overhead
transmission line. The TransLineCalc tool is completely
integrated with Simulator, which means that TransLineCalc
can be launched from Simulator, and then the results can be         Fig. 6. The skin of PSS/E
passed to Simulator.
C. PSS/E [3]                                                        D. PowerFactory [4]
The Power System Simulator for Engineering was                     The calculation program PowerFactory, as written by
introduced in 1976. Since then it became a widely used              DIgSILENT, is a computer aided engineering tool for the
commercial network simulator tool. This program is used for         analysis of industrial, utility, and commercial electrical power
long-term network planning, grid-connection plan checking           systems. It has been designed as an advanced integrated and
and for many ad-hoc studies by the Hungarian Transmission           interactive software package dedicated to electrical power
System Operator (MAVIR). It provides the user with                  system and control analysis in order to achieve the main
advanced and proven methods in many technical areas,                objectives of planning and operation simulation.
including:                                                             The name DIgSILENT stands for „Digital SImuLation and
Electrical NeTwork calculation program”. DIgSILENT
Version 7 was the world‟s first power system analysis
software with an integrated graphical one-line interface. That
 Balanced or Unbalanced Fault Analysis
interactive one-line diagram included drawing functions,
 Dynamic Simulation
editing capabilities and all relevant static and dynamic
 Extended Term Dynamic Simulation
calculation features.
 Transfer Limit Analysis
The PowerFactory package was designed and developed by
 Network Reduction
qualified engineers and programmers with many years of
Ending with version 30, it used to be two different
experience in both electrical power system analysis and
programs, for load flow calculation and dynamic simulations,
programming fields. The accuracy and validity of the results
but since version 31 it is realized in one package. It is also
obtained with this package has been confirmed in a large
easier to handle the software. It has three „main modules‟. The
number of implementations, by organizations involved in
planning and operation of power systems.
and short circuit calculations. Fixed slope decoupled Newton-
In order to meet today‟s power system analysis
Rapshon and Full Newton-Raphson methods are used
requirements, the DIgSILENT power system calculation
frequently, but it contains also Gauss-Seidel method. The
package was designed as an integrated engineering tool which
software is able to handle three-winding transformers, tap-
provides a complete ‟walk-around‟ technique through all
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available functions, rather than a collection of different
software modules. The following key-features are provided
within one single executable program:
 PowerFactory core functions: definition, modification
and organization of cases; core numerical routines;
output and documentation functions
 Integrated interactive single line graphic and data
case handling
 Power system element and base case database
 Integrated calculation functions (e.g. line and
machine parameter calculation based on geometrical
or nameplate information)
 Power system network configuration with interactive
 Generic interface for computer-based mapping
systems                                                   Fig. 7. The main window of PowerFactory
By using just a single database, containing all the required
data for all equipment within a power system (e.g. line data,
generator data, protection data, harmonic data, controller                             III. SIMULATIONS AND RESULTS
data), PowerFactory can easily execute any or all available         A. Examination of voltage levels and short-circuit powers
functions, all within the same program environment. Some of
The first group of the simulations examined a basic, but
these functions are load-flow, short-circuit calculation,
very important question, the voltage levels. When comparing
harmonic analysis, protection coordination, stability
four so different software, the load-flow calculation can be the
calculation and modal analysis.
first point to decide, whether all elements are modelled
The author‟s opinion is quite similar. PowerFactory is a
correctly, no parameter is missing and no data is invalid. If
very powerful simulation tool. It is capable of performing
there is significant difference in voltage values and/or trends,
different calculations at high level. There are number of
it is almost sure, that something is wrong. During this
variable features concerning for example a load-flow, so an
simulation, voltage of the 400 kV bus was held at nominal
exact question can be examined arbitrarily. The software is
level by the slack bus. Fig. 8. and 9. show the results for high
able to calculate grids with very little power flow, which
voltage and medium voltage buses respectively.
makes it perfect for the analysis of the distribution network, or
micro grids. There is high amount of built-in models available,
but in case this does not satisfy us, we are able to create our
own models, which gives us a free hand in designing. Another
powerful feature of the software is its built-in programming
language, DPL (DIgSILENT Programming Language). With
the use of DPL, not only various calculations may be
performed, but it also makes it possible to use short scripts.
The syntax of the language is similar to C and easy to learn or
use. The disadvantage in connection with PowerFactory is the
same thing as its advantage; the complexity of the program
requires a practiced user to handle it well. Though basic
calculations are easy to perform, it takes a little time to get
used to the software, and exploit its potential. To summarize,      Fig. 8. Bus voltages of the high voltage buses
the authors‟ opinion on DIgSILENT PowerFactory is very
positive, we find this software perfect for any kind of power
system analysis for people with some experience is such
software.
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Fig. 9. Bus voltages of the medium voltage buses                   Fig. 11. Short-circuit currents

Results of PowerFactory and Power World are almost the
B. Examination of island operation
same, while the other two software calculated lower values.
This is the outcome of the difference between the transformer         The second group of the simulations investigated a
models. The trend of the voltages is basically the same in all     different state of the network. In this case, our network is
cases though.                                                      separated into two parts, with the opening of the VN1A-
The second thing we can easily examine is the power flow        MT1A and VN1B-MT1B lines. Now the 120 kV substation of
between specific nodes. Active power flow can reveal the           Mosonmagyaróvár, and its region can be treated as an island,
errors of load/generation values, while different reactive flows   where (partly due to the high penetration of renewable energy)
can indicate different line modelling. Fig. 10. shows the active   generation and load values are almost equal, so operation is
power flows between specific nodes.                                stable. During these simulations, there are two generators
acting as a system slack. In the island, the gas turbines
connected to MO1G serve as slack, while the generator
connected to G4 remains the slack of the other part.

Fig. 12. Topology of the island (Power World)
Fig. 10. Power flows in the network

It can be observed, that the values are almost the same, and    Fig. 13. and 14. show the bus voltages for high voltage and
in some cases, equal in all four software.                         medium voltage buses respectively.
Another calculation that is useful for such comparison is
simulating short-circuit faults at different points of the
network. The first bigger obstacle is faced here. All programs
can calculate short-circuit currents, voltages and powers, but
their methods show major differences. For example,
PowerFactory alone is able to calculate short-circuit following
not less than 3 methods. These differences are easy to observe
when calculating asymmetrical short-circuit faults, so in this
paper, only 3 phase faults are compared.
During the simulations, 3 phase short-circuits were
performed at 5 different buses of the system, one by one. In
Fig. 11. steady-state current values are compared.
Fig. 13. Bus voltages of the high voltage buses, island operation
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V. REFERENCES
[1]   A. Faludi, “Teljesítményáramlás vizsgálata számítógépen “, lecture in
Hungarian, 2003, [Online].
Available: http://www.vet.bme.hu/okt/foszak/ver/labor2/tananyag/teljara
m.pdf
[2]   ***, “Power World Simulator”, Homepage, 2009, [Online].
Availabe: http://www.powerworld.com/products.asp
[3]   ***, “PSS/E Version 31”, Brochure, 2009, [Online].
Available: https://www.energy.siemens.com/cms/00000011/en/ueberuns
/organizati/services/siemenspti/Documents/updated_2008-
11/brochure_PSSE_en_letter.pdf
[4]   ***, “DIgSILENT PowerFactory Version 13.1 Manual‟, 2005

VI. BIOGRAPHIES

Fig. 14. Bus voltages of the medium voltage buses, island operation   István Vokony was born in Mosonmagyarovar in Hungary on October 19,
Short-circuit calculations were also performed in island           1983. He graduated at Revai Miklos grammar-school in Gyor, and studied at
operation. In this case, due to the altered number of machines                                the Budapest University of Technology and
Economics Faculty of Electrical Engineering and
(and thus short-circuit power), significant change can be                                     Informatics Department of Electric Power
observed in current values, as it can be seen on Fig. 15. as                                  Engineering. He is Ph.D. student at Budapest
well.                                                                                         University of Technology and Economics Faculty
of Energetic and Electrotechnics. He is member of
the Hungarian Electrotechnical Association and the
BUTE Student Association of Energy

Bálint Hartmann was born in 1984. He received
M.Sc. degree in electrical engineering in 2008. He is full time Ph.D. student at
the Department of Electric Power Engineering, Budapest University of
Technology and Economics. His fields of interest
include distributed generation, renewable energy
sources and smart grids. He is the president of the
Student Association of Energy.

Fig. 15. Short circuit currents, island operation

IV. CONCLUSIONS                                                   Tamás Decsi was born in 1982. He received M.Sc.
degree in electrical engineering in 2006. He is a Ph.D. student at the
During the examinations useful conclusions could be drawn
Department of Electric Power Engineering, Budapest University of
down. In cases, when the parameters of the models could be            Technology and Economics. He is working with MAVIR Hungarian
set similar to each other, the simulation results were also           Transmission System Operator Company Ltd..
similar. The reason for the differences of the simulation results
can be caused by the following:                                       András Dán, Dr. is Professor with the Department of Electric Power
Engineering, Budapest University of Technology and Economics. He received
 the input parameters of the simulators are not the             M.Sc. degree from Budapest Technical University in 1966, Ph.D. and D.Sc.
same                                                        degrees in Electrical Engineering from the Academy of Sciences in 1983 and
 there are input parameters existing in one simulator                                     2005 respectively. His expertise is in power
electronics, power quality and reactive power
but missing from the other one                                                        compensation especially associated with power
 the load- and voltage bases are different                                                system                                harmonics.
 the dissimilar inward calculating methods could
result in differences
To sum up, it can be concluded, that prior to modelling it is
worth examining which simulator is the most appropriate for
the task we want to perform. Before modelling the homepage
or the users‟ manual of the simulator are recommended to
search for in order to gain information on the essential
function of the program.
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