The Power System Analysis Toolbox (PSAT) is a MatLab based toolbox, with a command line version which is also GNU Octave compatible. A GUI is implemented, along with a Simulink-based library for network design. PSAT is capable of numerous functions, as listed:

• Power Flow
• Continuation Power Flow
• Optimal Power Flow
• Small Signal Stability Analysis
• Time Domain Simulation
• Phasor Measurement Unit Placement

It is also capable of converting data files from a large number of formats, and exporting results to EPS, plain text, MS Excel and LaTeX files. PSAT allows users to incorporate user defined models, FACTS models, and wind turbine models, and provides an interface to the GAMS and UWPFLOW programs.

Developer: Federico Milano, from of the University of Castilla, La Mancha.
Contact: Federico.Milano@uclm.es

Further information on PSAT may be found on the developer’s website:
http://www.power.uwaterloo.ca/~fmilano/psat.htm

* While PSAT is a free software toolbox, the user manual is no longer available for free without purchase.

UWPFLOW implements continuation and direct methods to locate fold bifurcations in AC/DC/FACTS power systems. The program is designed by C. Canizares et al. from the University of Waterloo. The program also generates a series of output files that allow further analyses, such as tangent vectors, left and right eigenvectors at a singular bifurcation point, Jacobians, power flow solutions at different loading levels, voltage stability indices, etc. The program has been developed in C and C++, and runs under Windows and UNIX environments.

The program reads files in the following formats: WSCC/BPA/EPRI formats, and the IEEE common format. FACTS device data, steady-state load model data and steady-state generator data formats are described in the program’s online help.

Developer: Claudio A. Canizares
Contact: ccanizar@uwaterloo.ca

Further information on UWPFLOW may be found on the developer’s website:
http://thunderbox.uwaterloo.ca/~ccanizar/software/pflow.htm

Voltage Stability Toolbox (VST) is designed to analyse the voltage stability problem and provide intuitive information for power systems planning, operation and control. To use this toolbox, MatLab and MatLab Symbolic Toolbox are required, on either a Windows or UNIX platform. The installation files include pre-compiled executable files for the IEEE 3, 5, 14 and 30 Bus systems, along with IEEE common data format files.

Capabilities of VST include:

• Power flow
• Static and dynamic bifurcation analysis
• Time domain simulation
• Jacobian eigenvalue analysis

Developer: Center for Electric Power Engineering, Drexel University
Contact: chika@nwankpa.ece.drexel.edu

Further information on VST may be found on the developer’s website:
http://power.ece.drexel.edu/vst.html

Power Systems Toolbox is a set of coordinated MatLab m-files which model power system components necessary for power flow and stability analysis. Demo examples are included in the toolbox, along with several sets of dynamic data and a user manual. MatLab is required to run this toolbox, and in the MatLab environment, users can customize power component models easily to match their specific systems under study. P/V and Q/V curves can be obtained, and the PST can be used for damping controller design as well, as ABCD matrices can be calculated by applying small perturbations to each state in the system. Up to 200 buses can be simulated.

Some drawbacks are apparent with this toolbox. The program uses its own input file format and cannot read files in commercial software formats. There is a lot of room for improvement with regards to the user interface.

Originally conceived and developed by Dr. Kwok W. Cheung and Prof. Joe Chow from Renssealer Polytechnic Institute, it was most recently marketed and further developed by Graham Rogers (formerly Cherry Tree Scientific Software).

Further information on PST may be found on the developer’s website:
http://www.ecse.rpi.edu/pst/PST.html

PCFLO is a program capable of solving power flows, fault analysis and studying harmonics. The program was developed by Prof. W. Mack Grady, Electrical and Computing Department of the University of Texas, Austin.

Designed as part of a course in power systems, the software comes with some tutorial examples of performing power flow, fault and harmonic studies.

Further information on PST may be found on the developer’s website:
http://users.ece.utexas.edu/~grady/

A 12 bus version of PowerWorld Simulator is available for free. The demo version includes most of the available add-ons, including:

• Available Transfer Capability (ATC)
• Optimal Power Flow (OPF)
• Security Constrained OPF (SCOPF)
• OPF Reserves
•  PV/QV Curve Tool
• Transient Stability

The main limitation of this evaluation version is the number of buses allowed.

The Alternative Transient Program (ATP) is a program designed for simulation of transient phenomena of electromagnetic and electromechanic natures. ATP has extensive modelling capabilities and can simulate complex networks and control systems of arbitrary structure. Also, user-defined components can be specified. The trapezoidal rule of integration is used to solve differential equations of the system components in the time domain.

ATP is capable of interfacing to TACS (Transient Analysis of Control Systems) and MODELS (a simulation language) to enable nonlinear characteristics in control systems and components to be modelled, such as corona and arcs. ATP can handle symmetric or asymmetric disturbances, such as faults, lightning surges and switching operations (including commutation of valves). The feature FREQUENCY SCAN allows calculation of frequency response of phasor networks, and HARMONIC FREQUENCY SCAN (harmonic current injection method) allows frequency-domain harmonic analysis to be performed. The maximum number of buses is 6000.

Additional tools include a GNE for users to draw electrical diagrams, and various plotting tools.

Developers: W. Scott Meyer and Tsu-huei Liu
Contact: canam@emtp.org

Further information about this software tool can be found from the developer’s website:
http://www.emtp.org/

DigSILENT stands for Digital Simulation and Electrical Network calculation program and it was developed by DigSILENT Power Factory. It is a computer aided engineering tool that is widely used for industrial, utility, commercial and academic applications. DigSILENT has the ability to simulate load flow, fault analysis, harmonic analysis and stability analysis for AC, DC and AC-DC systems. Both converter faults and DC line faults can be modelled in DigSILENT.

DigSILENT can import and export data from PSS/E version 23 to 29. The output file can be converted to Microsoft Excel easily. User defined model in DigSILENT can be written with drag-and-drop transfer functions. The code can be written with C++ programming language. Many user defined models can be obtained from the support website. Ones can write their own model based on those models straightforwardly.

For voltage stability, PV and QV curves are not standard functions in DigSILENT. PV curve is obtained by increase the loading factor in the loads; only the power output of swing bus is increased. QV curve is obtained by putting a synchronous condenser at the considered bus. Therefore, the generation direction analysis cannot be done by DigSILENT.

For small signal stability, the participation factor can be calculated only with the generator speed variables. ABCD matrices cannot be obtained by DigSILENT, therefore it is difficult to use DigSILENT for controller design purposes.

Additional information on DigSILENT Power Factory can be found from the developer’s website: http://www.digsilent.com.au/Software/?option=PF

PSS/E is used by electrical transmission participants world-wide. The probabilistic analyses and advanced dynamics modelling capabilities included in PSS®E provide transmission planning and operations engineers a broad range of methodologies for use in the design and operation of reliable networks.

PSS/E can read the IEEE and PTI formats. The output is a text file format, which is easily converted to excel or other format. PSS/E can be used for:
· Power Flow
· Optimal Power Flow
· Balanced or Unbalanced Fault Analysis
· Dynamic Simulation
· Extended Term Dynamic Simulation
· Open Access and Pricing
· Transfer Limit Analysis
· Network Reduction
· Small Signal Stability

For voltage stability, the PV analysis tool provided in PSS/E requires source and sink systems to be defined. The tool helps to determine how much generation can be transferred between these two systems, not the loadability of the whole system as most other softwares do.

For small signal stability, with large power system and the number of state variables are more than 500, the output obtained by LYSAN function in PSS/E is not accurate. NEVA can be used in this case and has friendlier interface but need to purchase it as separated function.

The user-defined models and functions can be written by Fortran or Python. However, the help documents supported for this section are not sufficient. Ones can use GMP to buid their own models, which need to be purchased separately.

PSSE version 29 and 30 support the integration of a controller model developed by MatLab Simulink.

Further information on the PSS/E software can be found from the developer’s website: http://www.energy.siemens.com/us/en/services/power-transmission-distribution/power-technologies-international/software-solutions/pss-e.htm

Mudpack software is developed by The University of Adelaide, Australia, which is a comprehensive set of interactive software tools for:

· The conventional analysis of small-signal stability and damping performance of multi-machine power systems (i.e. eigenanalysis, mode shapes, participation factors, frequency & time response, etc.)
· Designing power system stabilizers (PSSs) and FACTS device stabilizers (FDSs)
· Assessing the relative effectiveness of PSSs and FDSs
· Co-ordinating the design of PSSs and FDSs
· Analysing the performance of Voltage Source Converter based HVDC transmission systems
· Analysing the performance of wind energy conversion systems
· Analysing the performance of modal estimators based on the ambient fluctuations of system variables


There is an emphasis in the package on:


· Simple procedures for the tuning of PSSs and FDSs.
· Assessing the relative effectiveness of existing stabilizers installed on both generators and FACTS devices in damping selected modes of oscillation.
· The co-ordinated tuning of stabilizers for both generators and FACTS devices.
· The analysis of the interactions between stabilizing controls.x

Additional information on Mudpack can be found from the following website: http://www1.eleceng.adelaide.edu.au/groups/PCON/PowerSystems/MudpackBrochure/brochure.html

PSCAD® (Power Systems CAD) is also known as PSCAD®/EMTDC™. It is a power system analysis software with an electromagnetic time domain transient simulation environment and graphical user interface. PSCAD is developed based on EMTDC solution engine, and it also relies on Fortran Compiler. PSCAD also supplies interface to MatLab.

As its name indicated, PSCAD is a highly graphical software which offers most widely used electrical elements as built-in models. If the component needed does not exist in the library, the user can always create user defined functions by using FORTRAN language or a combination of existing basic functions. This makes PSCAD very powerful and flexible, capable of studying many different applications.

PSCAD generally can be applied to investigate issues related to power flow, voltage stability, small signal stability, time domain simulation, fault analysis, grounding, system harmonics, protection coordination, electromagnetic transient study, balanced and unbalanced network analysis.

PSCAD is developed by Manitoba Hydro and Manitoba HVDC Research Centre Inc. PSCAD provide three editions, student, educational and professional. The student version can only have 15 electrical nodes, but this is free. For educational version, 200 electrical nodes are allowed, while this number is unlimited for the professional version.

Further information on the PSCAD software can be found on the developer’s website: https://pscad.com/products/pscad/

SimPowerSystems is a /Simulink based toolbox containing many widely used power system models (built-in functions). Like other Simulink toolboxes, a GUI is implemented. Also, it is compatible with other toolboxes within MatLab which makes it very flexible for different applications.

SimPowerSystems does not define explicitly the limitation of the number of buses in a network. SimPowerSystems provides three modes for simulation – continuous, discrete, and phasor. Although it states as a continuous solver, the program solves the network discretely with variable simulation step values. In the discreet mode, the sampling rate will remain the same. Time domain sinusoidal waveforms are generated in these modes. However, as for phasor mode only the real and imaginary components of the signal peak will be used in calculation, so this mode is basically frequency-less and frequency is considered to be a constant during simulation. Therefore, simulation speed will be improved significantly under this mode.

SimPowerSystems generally can analyse load flow, voltage stability, small signal stability, time domain simulation, fault analysis, grounding, system harmonics, protection coordination, electromagnetic transient study, balanced and unbalanced network analysis.

SimPowerSystems is developed by MathWorks based on MatLab/Simulink (GUI). Additional information about this toolbox can be found at the developer’s website: http://www.mathworks.com/products/simpower/

ETAP offers a suite of fully integrated Electrical Engineering software solutions including arc flash, load flow, short circuit, transient stability, relay coordination, cable ampacity, optimal power flow, and more. Its modular functionality can be customized to fit the needs of any company, from small to large power systems. Seperated into two versions, Modular engineering version and intuitive engineering version, ETAP offers different packages to each.

The following packages are offered to its Modular engineering version:

· Short-Circuit analysis (IEEE,ANSI, IEC)
· Arc Flash Analysis
· Load Flow Analysis
· Motor Acceleration Studies
· Co-ordination of Protective Devices
· Relay test set interface
· Transient Stability Studies
· Generator Start-up Studies
· Wind Turbine Modelling
· User define models
· Parameter estimation

The following are offered to its intuitive engineering version:

· Underground Thermal Analysis
· Cable pulling and ampacity
· Cable Sizing
· Ground Grid Analysis
· Distribution system:
o Unbalanced load flow analysis o OPF o Optimal Capacitor Placement o Reliability Assessment o Single-phase distribution · Transmission System: o Line Constant o Line Ampacity o Sag and Tension analysis o HVDC Transmission link o Transformer sizing and tap optimizing

Further details about the ETAP software can be found from the developer’s website: http://etap.com/

The NEPLAN Toolbox has been especially designed for researchers and developers which need to develop new power system models (e.g. control strategies) and new algorithm (e.g. Smart Grid applications). The Toolbox includes:
· The NPL NEPLAN Programming Library
· An easy to use C/C++ API
· A MatLab interface
· A Simulink interface


NEPLAN can be used for transmission, distribution and smart grid research. Recent version of NEPLAN includes renewable energy generator (wind generator) model for grid integration assessment of renewable energy source.

The main features of the NEPLAN are:
· Harmonic analysis.
· Protection system design.
· Reliability analysis.
· Low voltage analysis in distribution system.
· Power flow and optimal power flow analysis.
· Small signal stability analysis.
· Voltage stability analysis.
· Available Transfer Capability Analysis (ATC).
· Ground system analysis.
· Arc Flash analysis.
· Cable sizing.


More details about this software can be found on the following website:
http://www.neplan.ch

DSATools is a suite of state-of-the-art power system analysis tools and provides the capabilities for the comprehensive system security assessment including all forms of stability. DSATools includes necessary features and functions for power system planning and operational studies. In addition to rich modeling capabilities and leading-edge computational methods, the software package is loaded with many innovative application tools.

This advanced software suite includes the following main components:
· PSAT – Power flow and short circuit analysis tool
· VSAT – voltage security assessment tool
· TSAT – transient security assessment tool
· SSAT – small signal analysis tool


Detail information about this software can be obtained from the following website:
http://www.dsatools.com

DINIS, which stands for Distribution Network Information System, is an integrated data capture and electrical network analysis workstation package that can be operated as a standalone system, or integrated into other applications. DINIS is a product of Fujitsu Services. Key analysis features of DINIS are:

· Network analysis for three phase or single phase mixed, with unlimited loads
· Advanced transformer modelling including loads,
· Fault analysis to IEEE and ANSI standards
· Two phase unbalanced allocation
· Cable resistance effect
· Loss optimisation
· Automatic load allocation
· Reliability analysis


DINIS also has optional specialist integrated modules, including a transient stability module, among numerous others.

Detailed information about this software can be found from the developer’s website:
http://www.dinis.com/Index.htm

EUROSTAG® is developed by Tractebel Engineering GDF SUEZ and RTE. The objective is to provide accurate and reliable simulations of power systems dynamics. The advanced dynamic functions of EUROSTAG® allow for the full range of transient, mid and long-term stability to be analysed, by employing a robust algorithm using an auto-adaptative integration stepsize.

EUROSTAG has the added flexibility of being able to import and export data in various international formats, and provides a vast library of power system models, which can also be modified if required using a flexible graphical modelling language.

Key Functions:

· Load Flow Computation
· Full-scope dynamic analysis – a few seconds to several hours.
· Critical clearing time calculation
· Eigenvalues computation and system linearization


Small Signal Analysis, Dynamic Security Assessment and Dynamic Response Optimization can be purchased as separate add-ons.

Additional information about EUROSTAG can be found from the developer’s website:
http://www.eurostag.be/en/products/eurostag/the-reference-power-system-dynamic-simulation/

Simpow covers a wide field of network applications, with the main focus on dynamic simulation in time domain and analysis in frequency domain. Simpow also has an in-built programming language for users to create and tailor their own models and methods. In the past, Simpow has been used for system interaction studies for HVDC, HVDC Light, FACTS and wind power plants.

Simpow is used as an analysing tool by consultant engineers, universities as a laboratory tool for training under- and postgraduates and commercial research institutes. The basic functions of Simpow include:
· Load flow calculation
· Short circuit calculation
· Synchronous stability
· Transient stability
· Voltage stability
· Load shedding
· Load fluctuations
· Prime mover torque irregularities
· Machine dynamics
· Sub synchronous resonance
· Resonance frequency analysis by means of Eigenvalues
· Eigenvectors
· Sensitivity of Eigenvalues
· Frequency scanning
· Parameter scanning and modal analysis
· Harmonics Analysis (injection, distribution and summation of harmonics)
· Simpow Dips


Further information on this software can be obtained from the developer’s website:
http://www.stri.se/simpow

The CYME Power Engineering software is a suite of applications composed of a network editor, analysis modules and user-customizable model librarys. The modules available comprise a variety of advanced applications and extensive libraries. Modules can be separated based on the objective: distribution network analysis, or transmission and industrial network analysis.

Key Functionalities of the Distribution Network Analysis Modules:
· Unbalanced load flow
· Comprehensive fault flow analysis
· Load balancing
· Load allocation/estimation
· Optimal capacitor placement


Key Functionalities of the Transmission and Industrial Network Analysis Modules:
· Network Editor
· Power Flow
· Short Circuit
· Load Flow Contingency (N-p)
· Arc Flash Hazards
· Protective Device Coordination with CYME and CYMDIST
· Dynamic Motor Starting
· Harmonics
· Transient Stability
· Voltage Stability
· Optimal Power Flow
· Geographic Overlay
· Component Object Modeling


Further information on this software can be obtained from the developer’s website:
http://www.cyme.com/software/

SKM provides a host of Power System Analysis and ARC Study Tools. Two of the key tools are DAPPER and CAPTOR. DAPPER is an integrated set of modules for three-phase power system design and analysis, and includes the following features:
· Load flow and voltage drop calculations
· Impact motor starting
· Traditional fault analysis
· Demand and design load analysis
· Feeder, raceway and transformer sizing
· Panel, MCC and switchboard schedule specification


CAPPER is used for time versus current coordination drawings with one-line diagrams and setting reports. CAPPER allows coordination of protective devices and provides a comprehensive model library.

As well as these two tools, SKM offers tools for:
· Arc Flash Evaluation,
· Fault Analysis,
· Transient Motor Starting Analysis,
· Harmonic Analysis,
· Unbalanced/Single Phase Studies,
· Transient Stability Analysis,
· Reliability Studies,
· DC System Analysis,
· Electrical Grounding Analysis
· Cable Pulling Analysis


Additional information about SKM Power Tools can be found on the developers website:
http://www.skm.com/index.shtml

RTDS is a power system simulator that solves electromagnetic transient simulations in real time. The system is used for high speed simulations, closed-loop testing of protection and control equipment and hardware in the loop (HIL) applications. The simulator is a combination of advanced computer hardware and comprehensive software, and provides simulation in continuous, sustained real time. The developers list the following key features of RTDS:
· Smart grid applications
· Distributed generation – wind, solar, fuel cells...
· True hard real time response for closed-loop testing
· Protective relay testing – line, transformer, busbar, generator...
· Control system testing – HVDC, SVC, FACTS...
· Large scale real time simulations
· Powerful parallel processing hardware and custom I/O
· Advanced and comprehensive user interface
· Extensive, well proven power and control system component libraries

RTDS comes with RSCAD, a user-friendly interface made up of several modules, for calculation of cable and transmission line characteristics, build user defined models, etc. Includes libraries of power system, control system and protection and automation components, and supports automated batch mode operation, as well as interfacing small timestep VSC subnetworks. It is also capable of importing data from PSS/E and BPA.

RTDS is developed by RTDS Technologies, with a head office in Winnipeg, Manitoba, Canada, and representatives in Heidelberg West, Victoria, Australia, as well as many other locations around the world.

Further information on the RTDS software can be found from the following website:
http://www.rtds.com/index/index.html