Loadflow.Fault.Instructions

PCFLO Version 5.2, http://www.ece.utexas.edu/~grady/, July 28, 1998

PCFLO Version 5.2 User Manual

July 28, 1998

Prof. Mack Grady

Department of Electrical & Computer Engineering

University of Texas at Austin

Austin, TX 78712

Phone: 512 - 471 - 5231

FAX: 512 - 475 - 8198, or 512 - 471- 5532

email: [email protected]

http://www.ece.utexas.edu/~grady/

- 1 - PCFLO Version 5.2, http://www.ece.utexas.edu/~grady/, July 28, 1998

Setup Instructions

PCFLO performs loadflow, short circuit, and harmonics analysis. It reads column-formatted, comma-separated (CSV), or tab-separated (TSV) data. CSV/TSV data make it easy to use Microsoft Excel for preparing your input data and examining your output results. Excel’s sorting capabilities are especially helpful in reviewing, for example, total harmonic distortion at busses, or in finding transmission lines with overloads or busses with high or low voltages.

You will find that HOWDY.ZIP contains some column- formatted files, and some comma-separated or tab-separated (CSV/TSV) data files. Four CSV header files are also enclosed that you may find helpful when using Excel (files BDAT.HDR, LDAT.HDR, ADAT.HDR, SPECTRA.HDR). These header files should be placed at the top of CSV/TSV input data to describe the content of the spreadsheet columns.

For your information, PCFLO treats any row in a CSV/TSV input file that has a colon in column 1 as a comment line.

Setup Instructions: 1. Establish a new directory named PCFLO, 2. Download HOWDY.ZIP into it, 3. Pkunzip HOWDY.ZIP.

Disclaimer

Professor Mack Grady and the University of Texas at Austin give no warranty that all errors have been eliminated from this software. Neither Professor Grady nor the University of Texas at Austin shall be liable for direct, indirect, or consequential losses, damages, costs, expenses, claims, or fees of any nature or kind resulting from any deficiency in this software.

Professor Mack Grady, Department of Electrical & Computer Engineering, University of Texas at Austin, Austin, TX 78712. Phone: 512-471-5231, FAX: 512-475-8198, email: [email protected].

Instructions for Performing Loadflow, Short Circuit, Harmonics, and Motor Starting Calculations

Program PCFLO is common to loadflow, short circuit, and harmonics calculations. PCFLO (500 bus version) contains a simple dialog box where you specify the path and extension of the input files. PCFLOH is a 500 bus version, tailor-made for harmonics studies. Program HARMPLOT is used in harmonics studies to view voltage and current waveforms as well as network impedances.

The information in file OPTIONS instructs PCFLO to perform loadflow (including motor starting), short circuit, or harmonics calculations.

Input data for PCFLO can be either column formatted, comma-separated, or tab-separated. Most output files are formatted and comma-separated. Comma-separated and tab-separated data files are easily viewed and edited with Microsoft Excel.

PCFLO always reads data directly from files ADAT, BDAT, LDAT, OPTIONS, and SPECTRA. Their content and structures are explained in this document.

Loadflow

Step 1: Copy file OPTIONS.LF to your file OPTIONS and make any necessary changes.

Step 2: Copy the loadflow bus and line/transformer into files BDAT and LDAT, respectively. If area interchange data are desired, include them in file ADAT. Otherwise, ADAT is unnecessary and must be deleted.

Step 3: Execute PCFLO (i.e., PCFLO.EXE).

Step 4: The loadflow "printout" is found in file OUT1 and OUT4. File VSOLN contains the solved bus voltages. File ISOLN contains branch currents. File OUT5 contains a useful summary of both branch currents and bus voltages.

Short Circuit

Step 1: Copy file OPTIONS.SC to your file OPTIONS and make any necessary changes.

Step 2: BDAT must contain the conventional loadflow data plus, at a minimum, the positive sequence subtransient reactances of the swing bus and other generators and motors. If negative and zero sequence data are provided for generators and motors, including neutral grounding impedances, then PCFLO will be able to perform line-to-line and line-to-ground fault calculations (as well as three-phase fault calculations).

Similarly, LDAT must contain conventional loadflow data. Also, if line-to-line and line-to-ground fault calculations are to be made, then LDAT must include negative and zero sequence data, such as transformer connections, phase shifts, and neutral grounding impedances.

Step 3: Execute PCFLO. The "printout" is found in files OUT1 and OUT2. PCFLO builds impedance matrices ZBUS0, ZBUS1, and ZBUS2 for zero/positive/negative sequences, respectively. ZBUS1 is always built, but ZBUS0 and ZBUS2 are built only if sufficient data are provided in BDAT and LDAT.

While in PCFLO, enter the bus number and complex fault impedance, in percent. Enter as many combinations of bus numbers and fault impedances as you like, one at a time.

Step 4: The results are found in file FREP. FREP lists all the information for a three-phase fault, then a phase-b-to-c line-to-line fault

(through Z F ), then a phase-a line-to-ground fault (through Z F ).

Full Harmonic Study

A full harmonic study injects harmonic load currents and calculates harmonic network bus voltages, branch currents, and voltage distortion.

Step 1: Copy file OPTIONS.HS to your file OPTIONS and make any necessary changes.

Step 2: BDAT and LDAT must contain the same data needed for fault studies. In addition, BDAT must contain the characteristics of any connected nonlinear loads.

Step 3: User-specified harmonic current spectra for nonlinear loads can be placed into file SPECTRA if needed.

Step 4: Execute PCFLO (or PCFLOH). A loadflow is automatically invoked to help identify data errors.

Step 5: The "printout" is found in files OUT1, OUT2, and OUT3. PCFLO builds files VSOLN and ISOLN that contain the Fourier series of bus voltages, line/transformer/shunt element currents, and nonlinear device currents (load convention). The values are given in rms percent. PCFLO also builds file THDV which tabulates network voltage distortions.

Step 6: Graphical results can be viewed in the background of PCFLOH, or separately by executing program HARMPLOT. Use HARMPLOT (within Windows only) and its self explanatory menu-selects to view bus voltages and nonlinear device current waveforms (both in file VSOLN), as well as branch currents (in file ISOLN).

To execute HARMPLOT, first select its icon. Then, under the File Open option, choose file type ISOLN or VSOLN. ISOLN contains branch currents, and VSOLN contains bus voltages and nonlinear load currents. Select either of these files and plot the results on the screen. Up to four waveforms may be plotted on one graph. Using the Export option, plots may be saved as *.BMP files for printing with Windows Paintbrush.

(Note: Files ISOLN.WG and VSOLN.WG are provided as samples.)

Harmonic Impedance Scan

A harmonic impedance scan computes the Thevenin equivalent (i.e. driving point) harmonic impedances of network busses.

Step 1: Copy file OPTIONS.HZ to your file OPTIONS, and make the necessary changes according to Table 4.

Step 2: BDAT and LDAT must contain the same data needed for fault studies. In addition, BDAT must contain the characteristics of any connected nonlinear loads.

Step 3: Execute PCFLO (of PCFLOH). A loadflow is automatically invoked for either option to help identify data errors.

Step 4: The "printout" is found in files OUT1, OUT2, and OUT3. PCFLO builds the diagonal elements of either file ZBUS0, ZBUS1, or ZBUS2, depending on which phase sequence is requested. The values are given in percent. If desired, impedance scans can be limited to nonlinear busses.

Step 5: Graphical results can be viewed in the background of PCFLOH, or separately by executing program HARMPLOT. Use HARMPLOT (within Windows only) and its self explanatory menu-selects to view the impedance matrix elements (magnitudes and phase angles) for network busses (in files ZBUS0, ZBUS1, and ZBUS2, for zero, positive, and negative sequences, respectively).

To execute HARMPLOT, first select its icon. Then, under the File Open option, choose file type ZBUS. Select a ZBUS file and plot the results on the screen. Up to four waveforms may be plotted on one graph. Using the Export option, plots may be saved as *.BMP files for printing with Windows Paintbrush.

(Note: File ZBUS1.WG is provided as a sample.)

Motor Starting

Step 1: Copy file OPTIONS.LF to your file OPTIONS, and make the necessary changes according to Table 1.

Step 2: Copy the corresponding loadflow bus and line/transformer into files BDAT and LDAT, respectively. If area interchange data are desired, include them in file ADAT. Otherwise, ADAT should be deleted.

Step 3: Modify file LDAT so that the motor bus has a fixed series impedance-to-ground branch. The FROM BUS of the branch is the motor bus number, and the TO BUS is zero (i.e., ground). Since the starting current for a motor is approximately five-times the full-load run current, and at a very low power factor, the impedance should be approximately:

Z M = R M + jX M ,

where pf X M X M » , R M » , 5 · P M 5

P M , pf

are full-load motor power and power factor, respectively. The impedance should be entered in percent.

Step 4: Remove the motor P and Q load from file BDAT.

Step 5: Execute PCFLO. The results are found in files OUT4 and VSOLN. If the voltage at the motor bus falls below 80%, it may not start.

Summary of PCFLO Data Files

ADAT: Loadflow area input data. (PCFLO also creates temporary file ADAT.TMP)

ASOLN: Solved area data for loadflows.

BDAT: Bus input data.

BDAT.TMP: Unformatted bus data file built by PCFLO and read by FAULTS.

BORDER: File built by PCFLO that lists the busses in optimal order.

EXLOG: Echo print of screen messages.

FREP: Output for short circuit studies (produced by program FAULTS).

ISOLN, VSOLN: Solved branch currents and bus voltages for loadflow and harmonics studies. (Sine series format for Fourier series)

LDAT: Line and transformer input data.

LDAT.TMP: Unformatted line and transformer data file built by PCFLO and read by FAULTS.

OPTIONS: User input solution options.

OUT1, OUT2, OUT3: Echo print of input data for loadflow, short circuit, and harmonics, along with pertinent messages and errors.

OUT4: Loadflow output data.

OUT5: Loadflow summary output used for wheeling analysis.

SPECTRA: User input harmonic current injection spectra. (PCFLO also creates temporary file SPECTRA.TMP)

THDV: Solved total harmonic voltage distortions for harmonics studies.

ZBUS0, ZBUS1, ZBUS2: Solved zero/positive/negative impedance matrix elements for short circuit (rectangular form) or harmonic studies (polar form), in percent.

Prepared Input Data Files

(Note - always delete the old ADAT file before executing PCFLO)

18 Bus Distribution System for Harmonics Studies (Extension WG)

83 Bus Transmission System for Loadflow Studies (Extension COA)

5 Bus Distribution System for Harmonics Studies (Extension EL)

5 Bus Stevenson Loadflow Example (Extension S5)

6 Bus Stevenson Short Circuit Example (Extension S6)

9 Bus Stevenson Short Circuit Example (Extension S7)

36 Bus Industrial Short Circuit Example (Extension DP1)

232 Bus Distribution System for Harmonics Studies (Extension CHI)

Structure of Harmonic-Related Output Files

(Note - for loadflow studies, the formats of ISOLN and VSOLN are different from below but are self-explanatory when viewing the files. For short circuit studies, the ZBUS files are similar to below, but written in rectangular form)

Commas separate the header lines and fields shown below to facilitate their use with Microsoft Excel.

Data Field (starting from the left) Description

1 Harmonic number 2 From bus number 3 To bus number 4 Circuit number

5 Current magnitude - percent 6 Current phase angle (sine reference) - degrees 7 From bus name (at the first opportunity only) 8 To bus name (at the first opportunity only) 9 Loading level - % of line rating (for fundamental frequency only)

1 Harmonic number 2 Bus number 3 Voltage magnitude - percent 4 Voltage phase angle (sine reference) - degrees 5 Nonlinear device load current magnitude - percent 6 Nonlinear device load current phase angle (sine reference) - degrees 7 Bus name (at the first opportunity only)

ZBUS0, ZBUS1, ZBUS2

1 Harmonic number 2 From bus number 3 To bus number 4 Impedance magnitude - percent 5 Impedance phase angle - degrees 6 From bus name (at the first opportunity only) 7 To bus name (at the first opportunity only)

THDV contains a list of bus numbers with their corresponding names and voltage distortions.

Appendix

The formats and structures of the input data files are given on the following pages.

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