Case Formats

 

Simulator supports a number of case formats. You can both open and save cases using most of the following formats:

PowerWorld Binary (*.pwb) (Preferred Format)

For most users, the best choice of power flow case formats is the PowerWorld Binary format. This format stores the most complete set of case information but requires the smallest file sizes. Information stored in this format includes power flow data, economic parameters, case time variation/options values, and screen customizations. The only potential disadvantage of this format is that it is stored in binary form, which means that it cannot be viewed using a standard text editor. All the other formats are ASCII and thus readable in text editors such as Notepad.

One additional benefit of using the Powerworld Binary format is that with this format the case can be password-protected. This setting is available under Misc. Power Flow > Set Case Username and Password in the Case Options ribbon group on the Options ribbon tab.

PowerWorld Auxiliary File (*.aux)

Simulator can save and load cases using the PowerWorld defined auxiliary file format. When the aux file format is chosen as the save file type in Simulator, the data describing the entire case is written to a text file described by Simulator’s auxiliary file format. These files can be considerably larger than PowerWorld Binary files, and generally should not be used unless otherwise necessary. Note that not all auxiliary files represent an entire case, and in fact in most cases do not. Only when an auxiliary file is created using the Save Case As option in the File menu  in Simulator does the auxiliary file contain all necessary information for loading the complete case in Simulator as an auxiliary file.

The Complete Case Auxiliary File Export Format Description can also be used for saving a case in the auxiliary file format. This is a newer preferred method of saving in this format and provides options for what type of data to save.

PowerWorld Auxiliary File - Secondary Keys (*.aux)

This option is the same as choosing PowerWorld Auxiliary File except for the key identifiers for each record. Instead of using the primary keys (i.e. bus numbers) to identify devices in the data, the secondary keys (i.e. combination of bus name and nominal voltage) will be used as the identifiers in the saved file.

PowerWorld Auxiliary File - Labels (*.aux)

This option is the same as choosing PowerWorld Auxiliary File except for the key identifiers for each record. Instead of using the primary keys (i.e. bus numbers) to identify devices in the data, the device primary labels will be used as the identifiers in the saved file.

PTI Raw Data Format (*.raw)

This format is included primarily for interchange of power flow data with other packages. The PTI Raw Data format only contains power flow data.

PTI Raw Data Format (*.raw) (with options)

This format is the same as the PTI Raw Format except that the PTI RAW File Load Options dialog will be opened to allow user input for various options.

GE PSLF Format (*.epc)

This format is included primarily for importing load flow data saved from GE's PSLF program. The EPC format is a text file format. This format does contain excess information that Simulator does not use, however Simulator does store this information for editing and writing back out to EPC format files.

GE PSLF Format (*.epc) (with options)

This format is the same as the GE PSLF Format except that the GE EPC File Load Options dialog will be opened to allow user input for various options.

Areva HDBExport Format (*.csv)

Customers who use the Areva EMS system are able to use a command in the Areva EMS called HDBExport to save a comma-delimited file containing a complete description of the network model in the EMS system. The CSV file must be exported using appropriate flags and a specific pattern file in order to generate the format required by PowerWorld. Simulator cannot save files in this format. The resulting file will be a full-topology representation of the network model appropriate for use with the Integrated Topology Processing add-on. For more information, please contact PowerWorld Corporation offices.

Simulator can also load display files created from an Areva EMS system. Please contact PowerWorld for more information.

BPA IPF Format (*.net)

The BPA IPF Format is another format which can be read from our customers in China.

IEEE Common Format (*.cf)

The IEEE Common Format is used to specify only power flow information. CAUTION: IEEE common format does not support many of the formats used in the PowerWorld packages, such as multiple loads and generators at a bus. Usually, IEEE Common Format is used only for inputting cases.

PowerWorld Simulator Project Files (*.pwp)

Project files are described in Overview of PowerWorld Simulator Project Files.

ABB Spider EMS (*.dat)

Text format that is exported from an ABB Spider EMS.

UCTE Data Exchange (*.uct)

This is a format adopted by a number of European countries for the exchange of power flow and short circuit studies. Simulator cannot save files in this format.

 

Advanced settings for opening cases are available under the File Management settings.

 

Special Data Handling

Some special handling of data may occur when loading, appending, or saving data in the various formats. The following details some of what occurs in these situations but is not an all-inclusive list.

 

PowerWorld Binary (*.pwb)

Appending

• Appended data completely overwrites an existing record corresponding to the same bus number(s).
• Branch elements are appended to a case only if both of their terminal buses exist.

PTI RAW Data Format (*.raw)

Reading

• Voltages at any radial buses are set to the voltages of the bus at the other end of the radial branch. This is done as long as there is no shunt charging or conductance on the branch, the branch is not a transformer, and not generators, loads, bus shunts, or switched shunts online at the radial bus. This is done to facilitate power flow convergence.
• The participation factors of generators are set to the PMax MW of the unit and not the generator MVA Base.
• When reading a RAW file that has comments on a given line, the comments will be loaded into the Memo field of the corresponding data record. However, the Memo field will not be written back out when saving a RAW file.
• When reading switched shunt records, a mode of 3 will now be interpreted as controlling the Mvar output of generation. Mode 4 and 5 to not correlate to features in Simulator, so these are treated as shunts with a constant Mvar.
• Will flag any non-transformer branch with R=0, B=0, and X<0 as a series capacitor. This is especially important when using the Geomagnetically Induced Currents Add-on (GIC) as series caps will block the DC GIC flows.
• When reading a RAW file there is a process to check the voltage magnitude and angle of star buses at the end of the RAW file read, and evaluate the mismatches at the three terminal buses of the three winding transformer. If it is determined that PowerWorld own estimate of what the voltage and angle should be at the star bus results in improved mismatches at the three terminal buses, the estimated voltage values to the star bus will be applied, otherwise the voltage magnitude and angle as read from the RAW file for the star bus will be kept.
• When reading of the RAW file format if comments are found for data records of the format /* [ my label, my second label ] */, then labels will automatically be created for the object. The string parsing removes all leading and trailing /, *, or space characters. Then if the remaining string starts with a [ and ends with a ], PowerWorld will assume that what is inside the bracket is a comma-delimited list of strings representing labels.
• When reading a RAW file, the options to specify the starting bus number of star buses are now stored in the computer registry.
• When reading VSC DC Lines from a RAW file so that the DC MW Setpoint is interpreted as the "AC side" MW.
• Modified reading of RAW file records for Bus, Gen, Load, Line and Transformer so that if an extra field is at the end of a record which is not expected, then we will try to read this in as a memo or label.
• When reading a RAW file set the 'Default' Limit Set for contingency voltage rating set to B to match how bus specific limits are loaded; the Normal bus ratings are put in rating set A and the Contingency bus ratings are put in rating set B.

Appending

• Appended data completely overwrites an existing record corresponding to the same bus number(s).
• Branch elements are appended to a case only if both of their terminal buses exist.
• Any new buses or branches that are created are now flagged as having just been added. This flag is then used as part of the pre-processing feature in the power flow solution to automatically estimate appropriate voltage magnitudes and angles for any existing or new branches and buses that become newly energized.
• A field, EPC File\EPC Modification Status, is populated to indicate whether an object is new or modified while reading. Even though this is a field that is normally associated with loading in an EPC file, the meaning is the same so the same field is used.

Saving

• When saving a case as a PTI RAW files the switched shunt records will always write out at least one block. If none exists, a single block with 1 step and size equal to the present MVar output is written.
• If a generator is using line drop or reactive current compensation, it will be set to regulate its own terminal bus with the setpoint set to the voltage of the terminal bus. Line drop and reactive current compensation is not supported in the RAW format.
• The Simulator software version number and build date is added to a comment at the top of an exported PTI RAW file.
• When saving a case as a PTI RAW format, if the option in Simulator is set to "DC Side", then the appropriate AC flow will be calculated and written out to the RAW file instead.
• When writing to a RAW file labels can optionally be written as comments in the format /* [ my label, my second label ] */.
• Generator records will be written out with WMOD = 1 when the FuelType =SUN (Solar) OR Unit Type = PV (Photovoltaic) within Simulator

GE PSLF Format (*.epc)

Reading

• If the latitude and longitude values are both zero when loading an EPC file, both entries will be ignored as invalid.
• A designation of the area and zone of a GE branch and transformer will be stored when loading from an EPC file.
• When loading multi-terminal dc lines from an EPC file, current limits for dc converters will not be enforced. This is set via a field, Enforce Current Limit, available with dc converters.
• When reading in a GE EPC file, the "aloss" parameter is usually rounded to one bus or the other to be expressed in terms of the "From End Metered" field (except in the case of Multi-Terminal DC converters and two-terminal DC lines).
• Simulator does not consider load IDs to be case sensitive. If multiple loads are found with the same ID that vary only by the case of the characters, Simulator will attempt to create a unique ID for each load. An appropriate message will appear in the message log.
• Voltages at any radial buses are set to the voltages of the bus at the other end of the radial branch. This is done as long as there is no shunt charging or conductance on the branch, the branch is not a transformer, and not generators, loads, bus shunts, or switched shunts online at the radial bus. This is done to facilitate power flow convergence.
• The IDs of bus shunts (Bus Shunt Fixed Control Mode in Simulator) will be changed to new unique IDs if SVDs are read in with the same ID at the same bus. Previously, switched shunts with the same ID at the same bus would just be overwritten. SVDs with the same ID can still overwrite each other and Bus Shunt Fixed with the same ID can still overwrite each other.
• If an area's slack bus is specified to be a bus that is not inside the area, the area will be set off AGC and the area slack designation ignored.
• If the generators at an area slack bus are not assigned to the same area as their terminal bus, the generator area designations are changed to the area of the terminal bus.
• The option for using GE Base Load Flag > 0 to prevent Post-CTG response in Simulator is used by default.
• The participation factors of generators are set to the PMax MW of the unit and not the generator MVA Base.
• The scheduled voltage for devices controlling the voltage at a bus is set with the bus in the EPC file. In Simulator this is specified with individual devices, i.e. switched shunts and generators. The voltage setpoints for these devices will be set to the scheduled voltage specified with the bus.
• The ID field for Breaker data will be used as the circuit ID for the breaker if the length of this field is 1 or 2. If the ID field is blank or greater than two characters, the circuit ID will be dynamically assigned. The ID field will always populate the EMS ID field in Simulator. When writing an EPC file, the ID field for Breaker data will be written using the EMS ID field if this is not blank. If this is blank the circuit ID field will populate the ID field in the EPC.
• When reading transformer records in the EPC file will now recognize a negative "type" as an indication that control on this device is disabled.

Appending

• Appended data completely overwrites an existing record corresponding to the same bus number(s).
• Branch elements are appended to a case only if both of their terminal buses exist.
• Any new buses or branches that are created are now flagged as having just been added. This flag is then used as part of the pre-processing feature in the power flow solution to automatically estimate appropriate voltage magnitudes and angles for any existing or new branches and buses that become newly energized.
• A field, EPC File\EPC Modification Status, is populated to indicate whether an object is new or modified while reading.
• If a new three-winding transformer is entered which uses a bus number which is already used as a star bus by another three-winding transformer this will not be allowed and a new bus number will automatically be chosen.
• If appending an EPC file causes a transformer branch to be converted to a normal branch, a log warning message will show this.
• If the scheduled voltage for a bus is specified, the voltage setpoints for switched shunts and generators that are regulating this bus are also properly updated.
• Elements with a status value of -4 will have the EPC File\Flagged for Delete in EPC flag set to YES. Simulator will default these elements to in service.

Saving

• When saving a case as a GE EPC file the Multi-Terminal DC converters will write out the "aloss" parameter in a manner consistent with the EPCL file mtTAP.p
• When using the Present Topological Differences from Base Case tool and the removed elements are saved in the GE EPC file format the elements are saved with a status value of -4.
• If a generator is using line drop or reactive current compensation, it will be set to regulate its own terminal bus with the setpoint set to the voltage of the terminal bus. Line drop and reactive current compensation is not supported in the EPC format.
• When saving a switched shunt that is on either Generator Mvar or Wind Mvar control, the shunt will be written as fixed (locked) control.
• If the GE Ohmic Data Flag for branches is set to 1, R and X will be written in ohms and B in microMhos.
• Saving a removed multi-section line in the EPC format should correctly write the sections of the multi-section line with a status of -4. GE flagged for delete flag for multi-section line will be true if any section is flagged for delete.
• The brktype field will be written based on the Branch Device Type specified in Simulator. When writing a Disconnect the EMS CBTyp field in Simulator will be used if it is not blank. The brktype field in an EPC file has more options for different types of disconnects that are only identfied as Disconnects within Simulator and the EMS CBTyp field might contain a more specific type.
• When writing out transformers to an EPC file, if transformer is Fixed we will now always write type = 1. PowerWorld has a separate field indicating if a transformer's control is enabled and if it's disabled we write a negative sign on the type. However in EPC file type=1 means there is no control at all, so writing a -1 is strange as it means the transformer's control is disabled, but it has no control anyway. To avoid confusion, we just write a 1 instead.

Areva HDBExport Format (*.csv)

Reading

• When loading the hdbexport file, modified to automatically add two labels to each transmission line. One label starts with the "from" substation name and the other label starts with the "to" substation name.
• At the end of reading in an hdbexport CSV file, if any CBTyp values were encountered that were not recognized a dialog box will appear prompting the user to designate a Branch Device Type for each CBTyp (See the hdbexport Files section in File Management for more explanation on this).
• Additional bus labels are added when reading the MEAS records.
• When loading the hdbexport file, will read three-winding transformer records using the XF record's ID_XFMR field.
• When loading the hdbexport file, will read NDLIM records and the entries are read into a bus record's bus-specific limit monitoring settings allowing to be specific high/low voltage for particular nodes.
• When reading the hdbexport CSV file there is an option about whether or not to create 3-winding transfomers.
• When reading the hdbexport CSV file there is the ability to choose the default label delimiter.
• Added Primary field to specify which label specification should be used as the primary label with the custom Areva label definitions used with hdbexport files. This will be assigned when loading hdbexport files.
• Modified reading of CP records from hdbexport CSV files when VTARGET is not defined. We now set the RegHigh/RegLow = 1.4/0.6 for shunts and also set AutoControl = NO.