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PSAF - Modules

CYMFLOW

CYMFLOW is the analysis module of PSAF dedicated to Power Flow analysis in three-phase electric power networks. It is equipped with powerful analytical options and alternative solution techniques.

PROGRAM FEATURES

CYMFLOW utilizes state of the art sparse matrix/vector methods and multiple solution algorithms:

  • Full Newton-Raphson.
  • Fast Decoupled (with or without constraints).
  • Gauss-Seidel.

CYMFLOW is the main analysis module of PSAF and has a seamless interface with the other PSAF Modules namely:

  • CYMFAULT to communicate the pre-fault voltage profile, current flows and transformer tap positions, for fault studies taking into account pre-fault system loading.
  • CYMHARMO to communicate the fundamental frequency voltages and currents for harmonic distortion calculations.
  • CYMSTAB to communicate the initial conditions to the transient stability simulator.
  • CYMVSTAB for static Voltage Stability Studies.
  • CYM-Motor Start account for system wide voltage drops during motor start.
  • CYM-AC Contingency to solve unlimited variations of a base network.

Analytical Capabilities

  • Analyze Networks with thousands of buses and branches.
  • Multiple swing buses allowed.
  • Automatic swing bus selection for isolated subsystems.
  • Distributed Swing bus option.
  • Simultaneous solution for islanded networks.
  • Area Interchange with area control generators.
  • Generator reactive power limits and remote voltage control.
  • Local or remote control of voltage and reactive power flow through tap changing transformers.
  • Control of real power flow through phase-shifting transformers.
  • Switchable shunt element.
  • Generalized load modeling, including Constant Power, Impedance and Current.
  • Representation and control of DC lines.
  • Wind Energy Conversion Systems (WECS).
  • Modeling and representation of FACTS devices (UPFC and STACOM).
  • Transformer inrush currents.
  • Color coding on the network One-Line Diagram of overloaded equipment and buses with voltage violations.
  • User-defined units for Bus voltages and line flows for both tabular and graphical results.
  • Tabular reports can also be directly exported to other spreadsheet programs such as MS-Excel.

 

CYMHARMO

CYMHARMO is the PSAF module designed to perform harmonic penetration analysis in electric power systems.

PROGRAM FEATURES

CYMHARMO features both single phase and full three-phase modeling capabilities. It can flexibly and easily be applied to utility-type grids, industrial power systems and distribution feeders of any configuration.

CYMHARMO utilizes state of the art sparse matrix/vector methods with a three-phase nodal admittance network matrix representation.

The program interfaces with CYMFLOW to obtain the fundamental frequency current and voltage system profile for harmonic distortion calculations and waveform display.

CYMHARMO includes an extensive library of equipment such as:

  • Converter and generalized current source models.
  • Arc Furnace model.
  • Passive shunt filter models comprising single tuned, high-pass, double tuned and C-type.
  • Library of Single phase and three-phase transmission line models.
  • Induction motor models.
  • Single phase and three-phase transformer models.
  • Modeling harmonic sources of nonlinear loads.
  • User Defined modeling (Filters, Sources, etc.)

Analytical Capabilities

  • Phase or sequence analysis.
  • Driving point and transfer point frequency scanning analysis.
  • Voltage and Current Harmonic distortion.
  • Calculation of telephonic indices (TIF, IT, etc.).
  • Sensitivity analysis.
  • System equivalence.
  • Noise to Ground analysis.
  • Inductive coordination analysis.
  • Communication Interference analysis with slanted-exposure power circuits.
  • Harmonic cancellation analysis.
  • System detuning analysis.
  • Capacitor stress analysis.
  • Skin effect modeling.

Capacitor Stress Analysis

CYMHARMO includes a module for the stress analysis of all power capacitors installed in the network, including those incorporated in Filters.

The analysis reports the harmonic currents and voltages of each Capacitor as well as the total reactive power, RMS current, RMS voltage and peak voltage.

These quantities will be compared to user defined limits and any capacitor that violates any of those limits will be reported and highlighted on the network one-line diagram.

CYMVIEW, Simulation Results Management

CYMVIEW, is common to all simulation modules that generate any kind of charts. CYMVIEW is capable of managing the outputs of the PSAF different modules including CYMHARMO.

This includes the following:
  • Bar chart plots for voltage and current distortion versus Harmonic Order or Frequency.
  • Time waveform plots.
  • Impedance magnitude and phase plots versus frequency, for resonance and de-tuning analysis.
  • R-X plots.
  • Sensitivity Analysis Plots
  • Possibility to plot multiple results on the same graph.

 

CYMFAULT

CYMFAULT is the PSAF analysis module dedicated to simulating fault conditions in three-phase electric power systems. User friendly data entry, a multitude of reports and flexibility in applying all industry-accepted standards are features that make CYMFAULT an Indispensable tool for these very common and important system studies.

PROGRAM FEATURES

CYMFAULT adheres to North American ANSI C37.5, ANSI C37.010, ANSI C37.13 and International IEC-60909 guidelines. It also supports conventional short-circuit studies without reference to any particular standards.

The program interfaces with:
  • CYMFLOW, for fault studies taking into account pre-fault system loading.
  • CYMSTAB, to communicate the necessary data for single pole switching simulations.
  • CYMTCC, for protective device coordination settings.
  • ARC FLASH HAZARD, for Electrical Safety Criteria

Analytical Capabilities

  • Three-phase Line to Ground, Line to Line and Double Line to ground shunt faults.
  • Series faults (one-phase open, two-phase open and three-phase series unbalance).
  • Separate network reduction for ANSI X/R ratios.
  • Arcing Faults through user-defined fault impedance.
  • Mutual Coupling in Zero Sequence.
  • Three-winding transformers modeling in positive and zero sequence.
  • Phase shifts in /-Y transformer banks.
  • Close In and Line-End fault conditions.
  • Interrupting Device adequacy evaluation.
  • Automated Sliding Fault option on a transmission line and/or cable.
  • System wide voltage, current and machine contribution reports. (Phase and Sequence Values)

ANSI Short-Circuit Studies

CYMFAULT adheres to North American ANSI C37.5, ANSI C37.010, ANSI C37.13 for all duty types that are of interest to industrial fault studies.

  • Time Delayed
  • Contact Parting
  • Closing / Latching
  • Low Voltage Circuit Breaker

IEC Short-Circuit Studies

CYMFAULT adheres to the international IEC-60909 guidelines and supports all four types of fault currents that are of interest to industrial fault studies.
  • Initial Short-Circuit Current (I"k)
  • Maximum Asymmetrical Fault or Peak Current (Ip).
  • Breaking Fault Current (Ib)
  • Steady State Fault Current (Ik)

CYMBREAK - Breaker Ratings

CYMBREAK checks the validity of the current breaker size, and is designed to execute the appropriate simulation for high, medium or low voltage circuit breaker according to either ANSI or IEC standards.

The CYMBREAK engine allows the user to specify the breaker with information such as rated voltage, short circuit currents, temperature, etc. It is also possible to specify the breaker configuration arrangement such as 2, 1½, ring, etc. Then it determines if it is correctly sized in a steady state context or during a short circuit. Based on the breaker configuration, simulations are automatically performed on the worst system arrangement for each performed check.

CYMFAULT / CYMTCC Interface

CYMFAULT includes an interface module to our Protective Device Coordination Program CYMTCC.

This interface provides CYMFAULT user's with full access to the complete library of over 5000 protective devices available in the CYMTCC program. The user simply has to define the coordination path of the feeder on the one-line diagram of PSAF and export to CYMTCC.

CYMTCC will automatically generate the Device Time / Current curves for any devices setting adjustments along with the selected feeder one-line diagram.

 

CYM-Motor Start

The CYM-Motor Start Analysis Module operates in conjunction with CYMFLOW and is dedicated to simulating the effects of induction motor starting in three-phase electric power systems. This module is a reliable and easy to use tool for assessing system voltage dips and acceleration times of induction motors, using a variety of starting methods.

Induction Motor Starting

The Induction Motor Start analysis takes into account the inertial effects of the motor, user-defined load curves and supports several starting methods as listed below:

  • Across the line starting.
  • Shunt capacitor-assisted starting.
  • Resistor and/or inductor assisted starting.
  • Open / closed auto-transformer starting.
  • Variable frequency drives.
  • Slip ring resistor injection assisted starting.
  • Star-Delta assistance.
  • Manufacturer data input files.
  • Soft motor start.


The above motor starting methods are also supported in our CYMSTAB program.

Synchronous Motor Starting

The Synchronous Motor Start analysis takes into account the inertial effects of the motor and user-defined load curves, and supports several starting methods, as follows:

  • Across the line starting.
  • Shunt capacitor-assisted starting.
  • Resistor and/or Inductor assisted starting.
  • Open / Closed Auto-Transformer starting.

Detailed Mechanical Load Model

A detailed user-defined load torque representation is provided with the program along with the possibility to plot the nominal Electrical and Mechanical torque curves prior to starting the motor.

The load torque data can be entered from manufacturer data curves or with the equation of load torque versus speed.

Motor Parameter Estimation

In the absence of detailed information, the module includes support functions for deducing the induction motor equivalent circuit for Single Rotor, Double Rotor or Deep Bar Rotor Induction Motors, utilizing either of the following information:

  • Locked Rotor and No Load Test
  • Locked Rotor and Load Test
  • Nominal Conditions
  • Starting Conditions
  • Manufacturer Curve Data
  • IEEE Standard 112 TM-2004

This module also supports this estimation of synchronous motor electrical parameters from physical quantities.

CYMVIEW, Simulation Results Management

CYMVIEW, is common to all simulation modules that generate any kind of charts. CYMVIEW is capable of managing the outputs of different modules including the CYM-Motor Start analysis module.

This includes charts and reports for motor bus voltage, starting current, power factor, electrical and mechanical torque versus time. In addition, the time/current curve is generated for protective device coordination purposes.

 

CYM-AC

The AC CONTINGENCY operates in conjunction with CYMFLOW, for Power-Flow related contingency analysis. The analytical approach used is the same as CYMFLOW; i.e. the contingency analysis is performed using full AC power flow solutions (no dc approximations). The module features the sequential solution of all contingencies in a single run.

Analytical Capabilities

The contingency module is structured so that an unlimited number of "what-if" scenarios can be included in a given contingency study. All contingency-related system modifications refer to the base case network Single outages and/or multiple outages/modifications can be concurrently defined at will to represent an adverse contingency analysis scenario such as:

  • Modify Loads Globally, Individually or by Zone.
  • Modify Generation Globally, Individually or by Zone.
  • Connection and Disconnection of Branches.
  • Shunt Modification.
  • Addition and Removal of Induction and Synchronous Motors.
  • Connection and Disconnection of Buses.

Contingency N-1, N-2, N-3

By using this option, you can define a group of single-, double-, or triple-branch outage contingency studies (one, two or three branches out in each contingency study). You must specify the network branches that you are interested in, by voltage level and type. PSAF will create the desired Group automatically, including the corresponding studies.

Contingency Ranking

This feature allows you to add or eliminate contingency indexes (ranking) to the tabular report. This contingency ranking methodology is designated for the automatic ranking, selection of contingency cases and to identify the most severe contingencies.

 

CYMOPF

CYMOPF, the Optimal Power Flow analysis module of PSAF, supplements the analytical capability of PSAF by allowing the user to engage in advanced system planning studies to optimize system performance, examine cost-efficient operational planning alternatives, articulate system control strategies and rationalize equipment utilization, resulting in better overall system asset management.

CYMOPF calculates the "best possible" values for "higher level set points" considering a set of user-specified objective functions and a number of constraints. In this way, CYMOPF adds intelligence and, consequently, improves efficiency and throughput of power system studies significantly.

Algorithm

CYMOPF relies on robust barrier-method based nonlinear optimization techniques that permit fully coupled optimization, with the entire set of system control variables, including generation schedules, transformer taps, phase shifter settings, etc.

System constraints

System equipment constraints are observed, in particular bus voltages and line flows. More specifically, CYMOPF recognizes the following constraints:

  • Bus voltage magnitude limits.
  • Branch flow limits (MW, MVAR, MVA, Amps).
  • Generator reactive power limits.
  • Generator active power limits.
  • Adjustable bus shunt limits.
  • Adjustable branch reactance limits.
  • Adjustable load limits.
  • Transformer tap changer limits.
  • System constraints are either set individually or globally for different system studies.

Infeasibility Handling and Convergence Difficulty

CYMOPF includes infeasibility handling through automatic relaxation of immediate binding constraints and comprehensive constraint ranking severity indicators for cases that exhibit convergence difficulty.

Analytical Capabilities

CYMOPF is aptly suited in solving many problems typically found in today's less-regulated power markets such as:

  • Scheduling of Ancillary Services for reactive power and active power.
  • Development of system reference scenarios.
  • Voltage collapse analysis.
  • Transfer capability investigation.
  • Location based marginal cost assessment.
  • Implicit penalty function consideration.

In order to solve such problems the following objective functions are supported in CYMOPF:

  • Minimize fuel costs based on the either of the following functions:
    • Piece-Wise Linear,
    • Piece-Wise Quadratic,
    • Polynomial - Exponential.
  • Minimize active power slack generation.
  • Minimize active power loss.
  • Minimize reactive power loss.
  • Minimize Series Compensation.
  • Minimize Reactive Power addition.
  • Minimize Load Shedding.
  • Minimize the control variable movement Linear or Quadratic.
  • Maximize flat voltage profile.
  • Maximize voltage security index.
  • Maximize branch flow security index.

CYMOPF will also support multiple valid combinations of the above listed objective optimization functions while strictly respecting system constraints. System controls are automatically adjusted to provide least cost design or an operational mix.

The optimal solution insures that system losses, generation costs, Reactive Power support requirements and different objectives are simultaneously optimized.

 

CYMSTAB

CYMSTAB is the PSAF simulation module dedicated to simulating electromechanical transients in three phase electric power systems. It features an extensive library of equipment and controller models, the capability to include user-defined controls, a very flexible user-interface and powerful graphics.

CYMSTAB utilizes the simultaneous implicit trapezoidal integration solution technique for network, machine and controller equations. The program supports the capability to test the step response of controllers and User Defined Modeling for system equipment and controllers.

CYMSTAB includes an extensive library of equipment such as:

  • Turbo and salient pole generators
  • IEEE Excitation Systems including saturation modeling.
  • Power System Stabilizers.
  • Governor models comprising hydraulic, thermal, Diesel, and Gas Turbines.
  • Static Var Compensators.
  • Under-Voltage, Under-Frequency and Frequency Droop relays.
  • Power Swing and Impedance relays.
  • Induction motor models with frequency dependent modeling.


In addition to the above built in library the program includes a comprehensive Library of User-Defined excitation systems, governors and stabilizers.

Analytical Capabilities

  • LLL, L-G, LL and LL-G Fault application and removal
  • Line switching and line re-closing.
  • Single Pole re-closing including line charging effects.
  • Load shedding and Load increase.
  • Generation shedding.
  • Disconnection of Lines, cables and transformers.
  • Frequency-dependent modeling.
  • Networks with multiple frequencies.
  • HVDC modeling.
  • Possibility to monitor specific equipment during the simulation.
  • Generalized Load modeling at individual bus bars or throughout the system.
  • Disconnection of static Var Compensators.
  • Addition and Removal of shunts.
  • Direct on-line or assisted induction motor starting and stopping.
  • Automatic validation of maneuvers sequencing.
  • Verification of equipment and controller data.
  • Series capacitors and controls.
  • Possibility to vary the integration step during the simulation.
  • Possibility to interrupt the simulation temporarily and restart.
  • Range checking for controller settings and simulation parameters.
  • Synchronous motor starting.

User Defined Modeling

CYMSTAB features a unique ability to supplement the already wide array of hard-coded models for system equipment and controllers, by providing the user the additional possibility to model any desired control system by virtue of User-Defined modeling.

The User-defined modeling approach rests on the premise of interpreting, at run time, the User-defined equations.

The program is provided with an extensive Library of elementary functions and building block controls to model any control scheme, including system-wide operations.

WECS, Wind Energy Conversion Systems

CYMSTAB now includes extensive modeling capability of Wind Energy Conversion Systems (WECS) dynamics. The advanced solution algorithms provide the user with the necessary tools to carry out power system studies comprising wind farm installations.

Three types of wind-turbine generation systems are supported, namely

  • ECS-IG, for induction generators directly coupled with the AC grid.
  • WECS-HVDC, for induction generators connected to the AC grid through a Voltage-Source Converter (VSC) DC link.
  • WECS-DFIG, for doubly fed induction generators, featuring not only a direct stator connection to the AC grid but, also, a VSC-based DC link rotor energy recovery system, for variable turbine speed operation.
  • Wind modeling, accounting for "cut-in" and "cut-off" capability.
  • Two-mass drive train turbine-generator shaft model.
  • Blade Pitch control.

CYMVIEW, Simulation Results Management

CYMVIEW, is common to all simulation modules that generate any kind of charts. CYMVIEW is capable of managing the outputs of different modules.

  • Real-time plotting of variables.
  • Complete system-wide tabular reports generated with complete echo of the data used for the simulation.
  • Plotting of the variables specified in the User-defined models.
  • Capability to compare results from different simulations.
  • Capability to customize Units, Labels and Plots appearances.
  • Algebraic manipulation of plots and variables during plotting.
  • Unlimited number of graphs.

 

CYMVSTAB

CYMVSTAB is the analysis module of PSAF dedicated for the voltage security assessment of power systems.

In planning and operating today's stressed power systems, the ability to maintain voltage stability has become a growing concern.

CYMVSTAB is designed to meet this challenge by assessing the ability of the power system to maintain stable voltages under different contingencies and loading conditions.

Power system voltage instability is related to the lack of reactive power resources in the network. This is very similar to frequency instability in transient stability studies for systems that do not have sufficient spinning reserve.

PROGRAM FEATURES

Many aspects of voltage stability problems can be effectively analyzed with the Steady state or Static Power Flow based domain for a specified operating condition of the power system.

CYMVSTAB offers the user the same common format as our Power Flow Program CYMFLOW for entering the network data, defining the study parameters, report options and solving the network.

The program assess the voltage stability of a network by means of the two most common static voltage stability analysis techniques.

  • P-V Analysis (P-V Curves)
  • V-Q Analysis (V-Q curves)

All curves of monitored variables can be exported to CYMVIEW, which is capable of managing the outputs of different modules and storing the results for any number of simulations generated by CYMVSTAB.

P-V Analysis Approach

CYMVSTAB offers a comprehensive P-V voltage stability study analysis approach for the base case and for any credible contingency against which the voltage stability of the system is to be evaluated.

This is achieved by scaling up all the loads in user-defined steps for a given network, base case and all defined contingencies, either by Bus, Areas, Zones or Globally.

The steady-state P-V approach dictates that for each load increase, pertinent generators within the system, should be re-dispatched to match this load increase.

CYMVSTAB offers the choice of three methods of Generation re-dispatch namely:

  • Uniform Generation
  • Inertial Power Flow
  • Governor Response

The load flow is solved for each load profile while monitoring the bus voltages over a range of variation of the key system parameter which in CYMVSTAB is the load. Reactive power of a defined group of generators, reactive power reserve, and interface flow can also be monitored and reported.

The V-Q Analysis Approach

The V-Q approach is a steady-state tool that develops a curve, which relates voltage at a bus to the reactive power necessary to reach this voltage.

The V-Q curve generated represents the system voltage behavior when increased reactive power is withdrawn from a specific test bus, which is typically a critical bus in the network.

In other words, to determine the maximum reactive power that can be withdrawn before the voltage collapse of the system.

Modal Analysis

In addition to the voltage stability analysis techniques, there is a need for analytical tools capable of predicting voltage collapse in complex networks, accurately quantifying stability margins, power transfer limits, identifying voltage-weak points and areas susceptible to voltage instability.

The voltage stability module CYMVSTAB our PSAF series of programs can identify the contributing factors and sensitivities which in turn provide insight into system characteristics that are key elements for the development of remedial actions in the network.

The modal analysis incorporated in CYMVSTAB is designed to meet the above requirements by computing:

  • The eigenvalues that identify the different modes, which the system could become voltage instable.
  • The eigenvectors that provide information related to the mechanism of loss of voltage stability.
  • Bus participation factors for each mode that identify areas close to voltage instability.

CYMVSTAB has the unique feature that for both PV and VQ approaches, the modal analysis is applied at each operating point to determine the voltage stability critical areas by identifying the ten buses contributing most to each identified mode of operation.

 

WECS

CYMSTAB now includes extensive modeling capability of Wind Energy Conversion Systems (WECS) dynamics. The advanced solution algorithms provide the user with the necessary tools to carry out power system studies comprising wind farm installations.

Three types of wind-turbine generation systems are supported, namely

  • ECS-IG, for induction generators directly coupled with the AC grid.
  • WECS-HVDC, for induction generators connected to the AC grid through a Voltage-Source Converter (VSC) DC link.
  • WECS-DFIG, for doubly fed induction generators, featuring not only a direct stator connection to the AC grid but, also, a VSC-based DC link rotor energy recovery system, for variable turbine speed operation.
  • Wind modeling, accounting for "cut-in" and "cut-off" capability.
  • Two-mass drive train turbine-generator shaft model.
  • Blade Pitch control.

 

ARC FLASH

The ARC Flash Hazard is an add-on module to our PSAF, CYMDIST and CYMTCC programs. This module is primarily designed to analyze and promote the electrical safety for employees working on or near electrical equipment. By increasing the understanding and awareness of electrical hazards, it is possible to minimize the risk of exposure to them and consequently avoid injury to individuals who work on or near electrical equipment.

PROGRAM FEATURES

This module computes the necessary parameters required to assess the risk level and adopt the adequate safety procedures.

It complies with industry recognized standards and methods for performing ARC Flash Hazard calculations namely:

  • The Electrical Safety Requirements for Employee Workplaces (NFPA-70E-2004).
  • Institute of Electrical and Electronic Engineers (IEEE-1584-2002).

The above guidelines facilitate the calculation of arc flash hazards in different types of equipment in various power systems.

Seamless Interface to PSAF, CYMDIST and CYMTCC

The bus data of any network created with our PSAF, CYMDIST and CYMTCC software can be supplemented with ARC Flash related information such as working distance, bus gap, connected equipment and exposed circuit in cubic enclosers or in open air.

In addition, the ARC Flash Hazard module calculates the maximum bolted (3) phase short circuit levels at the desired work place (Bus) for ARC Flash Hazard calculations.

Program Features

The ARC Flash Hazard module also utilizes our CYMVIEW Simulation Results Manager Program to generate the required results, including:

  • Incident Energy versus Distance with a constant clearing time.
  • Incident Energy versus Time with user defined distance.
  • Flash hazard boundary versus Time.

Warning Labels

The program generates reports that can be printed directly on ARC Flash Hazard weatherproof warning stickers.

These warning stickers include all the necessary information such as :

  • ARC Flash Hazard boundary.
  • Energy density .
  • Hazard / Risk category class.
  • Personal Protective Equipment (PPE).
  • Potential shock hazard.
  • Limited, restricted and prohibited approach boundaries.
  • Equipment identification.

Multiple label formats are available, and the module provides you with the capability to customize your own labels.