Version history

0.9861  The powers of the unsymmetrical load are given as single phase
             powers.  February 13  2011.

0.986
  An error in the earth fault currents of YY-transformers corrected.
            A new parameter, the tilt angle of the top line, added to polygonal
           (quadrilateral) relays.
            The impedance sum calculator also calclates sum of impedances
            of transformers and transmission lines.
            The parameters on the unsymmetrical load can be given using
             powers, currents, and power factors.
             Transformers can be modeled as ideal transformers (zero impedance,
             zero magnetizing current)
             Transformer currents can be displayed using phasors.
             February 7  2011

0.9852
Another error in copying components (relays) corrected
            November 22  2010

0.985
  Scenarios = different sets of parameters introduced for the load component
            November 1  2010

0.984   Voltages displayed at buses in volts or per unit. Display of Thevenin impedance
            corrected (was in milliOhms!) September 5  2010

0.9831 An error in copying relays corrected  August 1  2010

0.983  Curves added to the PGQ-relay. An error (at low voltage) in the IEC-
           calculation corrected. Cursor lines (vertical/horizontal/none)can be selected
           in the coordination graph. Only inverse time or only definite time curves of
           combined relays can be shown temporarily. July 25  2010

0.9822 A node numbering error of 3-winding transformers corrected (resulted
            in erroneous "common voltage" in connected relays). Nominal voltage and
            alarm limits added to buses (work in progress, ready in version 0.984.) May 21  2010

0.982  Impedances of three-winding transformers can be given in per cent using
           the transformer base.  An error in reading old files corrected May 9  2010

0.9813 Errors in per-unit parameters of three-winding transformer corrected
            February 10  2010

0.9812
Not published

0.9811 Errors in IEC- and Z120-calculations corrected January 10  2010

0.981  Relays can be in "not in use"-state. Some errors corrected (parameters
           of transmission lines,..)   December 13  2009

0.98    
Several components can be in "not in use"-state  November 11  2009

0.979
 The parameters of  feeders can be given in different ways, including the per-
           unit notation.  October 7  2009

0.978   Added possibility to look current related relay parameters in different modes
           (in primary amperes, secondary amperes, normalized sec. amperes of the current
            transformer). August 14  2009

0.9772
More errors in copying parameters corrected. Help of the shunt capacitor
           calculator updated (slightly)   August  1  2009

0.977
 A shunt capacitor calculator added. Errors in copying parameters and
           in displaying activation times of some relays corrected.
           July 19  2009

0.976  More parameters for capacitors. Color to more components.
           June 16 2009

0.975
 The user defined relay can read curves from an excel file of type *.csv
           (not *.xls! )  May 1  2009

0.974
 Generator parameters can be entered using the per-unit notation.
           Ampage limits added to the generator. March 20  2009

0.973
 Parameter groups of relays can be changed automatically, when
           breakers are opened or closed. "Number of parallel generators"-
           parameter added to generators  March 9  2009.

0.9721
An error in reading the time multipliers of PGQ-relays from
           old files corrected  December 19  2008

0.972  Calculator for adding impedances of tr. lines added
           Time adder and multiplier added for PGQ-relay
           A (very) simple motor starting curve added
           Char.curves of relays can be hidden
           The star point of the unsymmetrcial load can be connected to ground
           December 8  2008

0.971
 Damage curve for transformer added. Transformer parameters
           can be entered also in pu-form    November 9 2008

0.970  Not published

0.969   Damage curve of transmission lines can be displayed. Parameters
            of transmission lines can be entered in several ways, also using
            per unit notation.  April 6  2008

0.9682
The phase shift in YD, DY, and YYD transformers can be
            -30 or +30 degrees. Thevenin impedance calculated also with
            transient impedances (and without asynch.machines). The
            activation times of relays reported in increasing order of the
            times (almost).  February 24   2008

0.9681 An error in the time difference calculation corrected.
            February 16  2008

0.968
Hide the labels can be set separately for different component types.
          The negative sequence impedance added for the feeder-component.
          The Thevenin impedance calculated also with "normal" reactances
          (previously only with subtransient reactances) February 13  2008

0.967 A "two open lines"-fault added. Different (rotated) positions for the
          three winding transformer and the unsymmetrical load added. Sequence
          currents displayed after an open line fault. February 7  2008

0.966  Current transformers have (optional) parameters (transformation
           ratio, etc.). The Open-Line-fault added. Peak and breaking
           currents added in the report, when IEC-fault. Parameter
           windows can be hidden.  January 22  2008
  
0.965
 Activation (tripping) times of relays displayed also after an IEC-
           short circuit calculation. Components can be deleted with the mouse
           only (right click, and select "delete" in the pop-up menu).
           Warning messages can be displayed. August 24  2007

0.9644 "Floating label" added to the coordination graphics (texts that
             "float" on the graph)  July 15 2007

0.9643 Not published

0.9642 Some Basler PGQ (phase-ground-sequence) relays added.
            The grounding impedance-component displays also the current.
             June 19  2007

0.9641 (Minor) errors in the latest additions corrected June 13  2007

0.964 More fuse curves added. Starting time in coordination graphics can be
         selected to be either 0.01s or 0.001s. Thickness and length of marker-lines
         can be set. Activation times of relays reported in increasing order. Relays
         can be removed from the coordination graphics. Max. number of curves
         in coordination graphics is 16 (was 10). June 11 2007

0.963 The difference between the activation times of two characteristic curves at a given
          current can be  calculated  in the coordination graphics     May 15  2007

0.9621 Errors corrected: Some relays appeared twice in the parameter report.
            The new, 3rd and 4th definite time modules were not included in all calculations.
            Labels of char.curves in the coordination diagram.

0.962   Six parameter groups added to relays. An occasional access violation error at
           exit corrected. April 12  2007

0.9619 Not published
0.9618
An error in the recloser relays and user defined relays corrected (It was not
            possible to change the parameter values. The error was entered in 0.9614)
            Note: *.sld files generated with this and later versions cannot be read with
           older versionsof the program!
April 5 2007

0.9615-0.9617 Not published

0.9614 An error in the feeder component in the *.atp files corrected. More definite
            time modules in combined relays. Shorter lines in the *.sld files.
            Note: *.sld files generated with this version cannot be read with
           older versions! March 14  2007

0.9612-0.9613 Not published

0.9611 Some test output removed  February 22  2007

0.961 A three-winding YYY or YYD transformer added
          but only in one orientation, so far. February 16  2007

0.9603 An error in the earth fault calculation corrected. (It was entered in 0.96)
            A list-index-error corrected. February 1  2007

0.9602 The circulating currents of transformers corrected once more.
            (It should be right now, I hope) January 20  2007

0.9601 An error in the title of the diagram corrected. January 18  2007

0.96 Undo - redo added. Corrected an error in the display of the circulating currents
        in the D-windings of transformers. The zoomed diagram improved (the zooming ratio
       can be selected, editing possible in the zoomed diagram). Editing of (large) diagrams
       improved. Units for results can be selected (A or kA, etc). Number of decimals can be
       selected in the report. Some fuse-curves added.   January 16  2007

0.951 An unsymmetrical load added (three different impedances in a star).
          A fault (or other component) can be somewhere between the endpoints
         of a transmission line.     Sept. 26   2006

0.95 The Thevenin sequence impedance can be calculated in all buses and voltmeters
        Winding currents in D (delta) sides of transformers can be displayed
        Possible to copy of parameters of components using tables
        The user can open/close several breakers by reading a file
        Some more breaker symbols added
        Note block of distance relays visible also without (fault) calculations
        Filtering added to the "find components" operation
        Saving of the list of components added to the "find components" operation
        August 30 2006

0.94    The fault current of a fault in each bus and each voltmeter in turn can be
           calculated by one click of a button.  August 14  2006

0.9381 A bug on displaying results after an IEC-calculation corrected.
           August 2  2006

0.938 The possibility to include a generating PQ-bus in a load flow calculation
          added. (PQ-bus = both real and reactive power defined, voltage solved.)
          This is done by allowing the load-component to have a negative apparent
           power. July 29  2006

0.936, 0.937 Not published.

0.935 The k0 calculator program and the differential protection calculator
          program can be started from Elplek (but all these programs must be
          in the same directory). Data can be moved from Elplek to these
          programs.  June 27 2006

0.932...0.934 Not published

0.931 The text "phase to neutral voltage" changed to "phase to ground
           voltage" in some texts, and in the help file, because the program actually
          calculates the phase to ground voltages. Some components now display
          also the voltage of the neutral point. April 28  2006

0.93   Several different breaker symbols added
          April 21  2006

0.92   More flexible point and line markers in the graphs
          March 31  2006

0.911 Errors in the special summing transformer corrected
          Feb 24  2006

0.91  A special summing current transformer added. (Can be used to
         construct a differential relay, for example) Feb 19  2006

0.901 The alternative symbol for transmission lines corrected. Now it should
          work also in Win 98, etc (previously only in Win XP)
          January  28  2006

0.90  List of open breakers added. A Voltmeter component added.
         Two different symbols are available for breakers, transmission lines
         and wires. Negative- and zero sequence voltages can be multiplied
         by three. All result boxes can be closed with one click (Click the xx
         in the result box.) Relay parameter window can be hidden.
         January 21  2006

0.891 A bug in moving the identifiers in the relay graphs corrected
          December 20  2005

0.89  "Find a component"-feature added. The possibility to select (or filter)
          components for reports added. Added more buttons to format the
          results-report.  December 12  2005

0.885 The access violation error of some relays corrected. November 4  2005

0.884 Some relay curves added to the existing curve families. Some more hide/show
          options to relay graphics. November 2  2005

0.883 Not published

0.882 The "Access violation" error (when deleting current transformers) corrected.
          Currents at time > 0 can be written to the report. Sept 30  2005

0.881 Different colors removed from the new result boxes of relays. The
          colored boxes worked properly only in Win XP. Sept 26  2005

0.88  More show/hide options in the graphics of distance relays. The activation
         times etc. of relays are displayed also in the result boxes. Sept. 25  2005

0.87  The induction motor can act also as a generator, by setting a negative value
         to the power parameter P (all other parameters must be positive)
         September 5  2005

0.861 The floating point bug (in distance relays) corrected. August 31  2005

0.86  The result boxes etc. of current transformers and distance relays (but no other
        components) can show the  results also for times > 0.  Aug.  26  2005

0.853 The label of the text component stays enabled after moving. Aug 16  2005

0.852  The text component corrected. It shows all three lines of text now, and
         also the texts are copied, when the component is copied. Aug.  16 2005

0.851  The values of current and time can be separated also with the tabulator
         in the file for the user defined relay. An exported diagram displays open
         switches with a yellow background also in the *.wmf format. The quality
        of the *.jpg files is slightly better (and the files are larger). The exported
        coordination graphics includes the notes, explanations etc. also in the
        *.wmf format, similarly as in the *.bmp and *.jpg format.

0.85 A relay with user defined characteristics added June 26  2005

0.84 The single line dagram and the different graphics can be exported also
        in the jpeg-graphics-format.  May 2  2005

0.83  Recloser relays added  April 28  2005

0.822 The characteristics of the electromechanical relay CDG14 corrected.
           March 18  2005

0.821 The setting of the value of the time multiplier-parameter with the
          "spin wheel" corrected in the electromechanical relays.
          March 18  2005

0.82 Some electromechanical relays added.  March 17  2005

0.81 Load flow with tap changers and solve net with tap changers added.
        Load flow "tolerates" a disconnected generator. Feb 12  2005

0.80  The load zone and the out of step zone added to the graph
         of the distance relays. The sequence impedances can be displayed also as
         magnitude and phase. More identifier (names) can be moved with the mouse
         in the graphs. The color of the grid can be selected in the graph of distance relays
         Jan 16  2005

0.791 A bug in the line to line fault corrected. (The results were wrong, if the
          calculations were carried out immediately after the calculation of the
          Thevenin sequence impedance.) Nov. 29  2004

0.79 The Thevenin sequence impedances calculated. The grid color of relay
        coordination graphics can be changed. The symbol for the impedance-
        component depends on the values of R and X. The identifiers of markers
        can be moved with the mouse in the coordination graphics.  The
        coordination graphics can be exported as a *.wmf file.  Nov. 28  2004

0.78  New features in the graph for distance relays: Scale can be changed.
         Markers can be added. Notes can be written. Title may be entered.
         The graph can be exported as a *.wmf file.
         An occasional "access violation"-error corrected (again).
          Nov 11  2004.

0.77   A polygonal distance relay added     Oct. 22  2004

0.76   The short circuit currents can be calculated according to IEC 60909
          (with some minor limitations) Sept 30  2004

0.754 Lines of constant current or time can be drawn on the coordination
          graphics page. Another occasional access violation-error corrected
          (in the coordination graphics page) Sept 19  2004

0.753 Identifier error in voltage phasors corrected. Power can be displayed
          as magnitude + phase. Sequence components of currents saved as a
          function of time (with other currents). Sept 9  2004

0.752 Voltages of buses can be displayed as phasors
           Sept 3  2004

0.751 Symmetrical components of currents can be displayed as phasors
          August 27  2004

0.75  Phasor display for currents added. An occasional access violation error
         corrected (in the coordination graphics). The identifiers of the curves of the
        coordination graphics page keep their position when resizing the page
         August 17  2004

0.742 The currents and activation times of relays are printed (and displayed
          with view | diagram) together with the single line diagram.
          June 15  2004

0.741 Diagram can be exported as a colored bitmap. Small errors in relay
          characteristics and in coordination graphics corrected. The vertical "text"
          removed in the text-component. The texts of the text-component included
          in the exported *.bmp and *.wmf-files. The marker of prefault current and
          other currents can be hidden in the coordination graphics. June 7  2004

0.74   The combined relay and coordination graphics finished. A text-
          component added. Buttons to hide the activation times and the
          text components added. Bus voltages and no. of components
          added to the report. May 28  2004

0.736 Some corrections and other small changes in the combined relay
          and in the coordination graphics of the test version.
           May 7  2004

0.735 The scales of the time and current axes can be changed, and other
          small changes in the coordination graphics page, and in the combined relay
          of the test version. For downloading, see above. April 26  2004

0.734  A title and a comment-box added to the coordination graphics page
           (a test version, so far). The relay list and the comments of the
           coordination graphics can be saved. For downloading, see above.
            April 16  2004

0.733  The test version of the combined relay improved and corrected.
           (For downloading, see above). April 8  2004

0.732 A combined phase-, residual-, and neq.sequence relay added to
          a test version, see above March 22  2004

0.731 Explanatory texts added to the distance relay impedance file.
          Edges and center of the visible part of the single line diagram drawn
          in the zoomed-out diagram window, in addition to the corners.
          (click view|diagram)  Feb. 18. 2004

0.73  Impedances measured by distance relays can be saved to file as a
         function of time. Some (minor?) bugs corrected. Feb. 17  2004.

0.72  Current or power displayed at current transformers. Activation times of
         relays included in the report. Sum current transformers included in the
         report. Feb 10  2004

0.711 The color of (some) components in the single line diagram can be changed.
          Right-click the component and select the color in the menu that appears.
          Feb. 6 2004

0.71 More colored components. The zoomed-out diagram can be used to
        navigate in the single line diagram. Opening and closing files (single line diagrams)
        speeded up. (But the new colored components may slow them back down)
        A printing bug corrected (the leftmost components were sometimes left out)
        Feb. 3, 2004

0.7    Some components can have different colors. The size limitation of
         reports removed  (Jan 23  2004)

0.692 Another bug in reporting currents corrected (Jan 20  2004)

0.691 A bug in displaying currents and powers of current transformers corrected.
         Some titles in the report corrected (Jan 20 2004)

0.69  The parameters of components can be written to a parameter report. "Save
         currents with time" saves also the phase angle. Current transformers display
         the power through the transformer. 3*Ineg and 3*Izero and power through
         current transformers saved also in  the report. (Jan 18  2004)

0.68  The program "remembers" some button states. The direction of current at distance
         relays included in the report. Three times negative and zero sequence currents
         can be shown. The scale of current extended in the graph, when phase currents
         shown. Currents of all phases and the sum current saved with the "Save currents
         with time.." command. (Jan 8  2004)

0.67  The user can select the period over which the currents are calculated in the case
         of a fault, 1s, 10s, or 100s.  A bug in the calculation of the activation time
         of inverse time relays corrected. (Dec 21  2003)

0.661 The tap-parameter of transformers changed: if tap > -20 and tap < 20
          then tap = the change in the secondary voltage in %, but if  tap > 0.8 * Vprim,
          then tap = a new value for the primary voltage (Dec 17  2003)

0.66  Transformers: 1) ratio of zero seq. impedance and pos.seq impedance added.
         2)tap changer added 3) minor bugs corrected (fault current in DD-transformer)
         (Dec 14  2003)

0.651 A printing error corrected, errors in the help file corrected.
          The short circuit component can have different orientations
          (Nov. 27 2003)

0.65  Help file updated. Some small bugs corrected (Nov 22   2003)

0.6475 Bounds for phase difference between the current and prefault voltage
            changed from +-90 degrees to +60 and -120 degrees for the distance
            relay in the zero voltage / ground fault / old method case.  (Nov 19, 2003)

0.6474 The old method for the zero voltage case of distance relays
            modified slightly in the case of ground fault. See above

0.6473 More bugs in the distance relay corrected. See above (Nov 9  2003)

0.6472 Another bug in the distance relays corrected (forward/reverse),
           and some other small changes in the experimental version. See above
           (Nov 5  2003)

0.6471 Oops again! A bug in the zero voltage check of the distance relays
            corrected. See above
            (Oct 31.  2003) 

0.647 A new way to check the zero voltage case in the distance relays.
         The new  experimental version ..., see above (Oct 29.  2003) 

0.6461 Oops! The condition for phase difference in the distance relay was
            the wrong way around in the experimental version (Oct 20.  2003)

0.646 In the experimental version, the distance relay checks the prefault
          voltage, if the actual voltage becomes zero due to the fault (Oct 20  2003)

0.645 The Access violation error corrected in
          the experimental version. (Sept. 30  2003)

0.644 A test version with an improved Mho distance relay can be
          downloaded NO MORE  (Sept.29  2003)

0.643 A test version of the program with an experimental Mho distance relay
          can be downloaded  NO MORE   (September 18  2003)

0.642 A test version of the program with the prototype of a Mho distance relay
          can be downloaded  NO MORE   (September 12  2003)

0.641 A test version with an experimental (and unfinished) ground distance
          relay can be downloaded NO MORE (August 16  2003)

0.64 The sequence components (+,-,0) are shown also on the main form
        (in the result boxes, and near to the current transformers).
        The format  of data written to the report (real+imag, or abs.value +phase)
        depends on the position of the " j/i " button (Aug 9  2003)

0.63 The occasional "access violation"-fault at shut-down corrected (I hope)
        The decimal point fault in the Per Unit calculator corrected (It did not
        always accept the decimal point)
        An upper limit for the self-inductance of transformers added. Equivalent
        to a voltage dependent lower limit for the "nominal primary open circuit
        current" Io.  (July 15  2003)

0.62 Bus voltages added to the report. In the cases of asymmetrical faults,
        the sequence (+,-,0) currents of current transformers and voltages
        of buses are written to the report (July 3, 2003)

0.611 A couple of resistors added to the *.atp file, in the case of asynchronous
         motors, because ATP does not like loose ends.  June 22  2003

0.61 A "connection bug" corrected. Sometimes, the program did not see
        that components were connected. (for example,  when a horizontal
        current transformer  was directly connected to a vertical bus) May 31  2003

0.6  Diagram can be exported as *.atp file for the ATP transient simulation program.
       A bug in generating the EMTP (*.dat-file) for transmission lines corrected
       Smaller minimum value for zero sequence impedance for feeders. May 20 2003

0.591 A bug in positioning out-of-screen elements corrected. (The bug
          distorted the example file ex3.sld) May 9  2003

0.59 The "earth-fault-bug" is corrected (actually, it was an "induction-
        motor-bug) May 9 2003

0.58 special symbols on parameter names (like " etc) returned. (they were
        mysteriously removed in the previous version)
        A bug in "undelete" corrected. (The "undelete" moved the component,
        if a copy-paste action had been carried out earlier) April 24  2003

0.57 Results displayed either as abs.value + phase, or real + imaginary values
        Value of prefault current indicated on graph of max. current
        after fault calculation (April 23  2003)

0.56 Graphs of currents of all phases (a,b,c) can be shown (press Alt while
        clicking the relay).
        The zero sequence impedance of feeders cannot be zero (after all).
        It must be equal or larger than the internal impedance. (April 10, 2003)

0.55 Larger limit for printer scaling factor
        Initial messages (the about box) can be hidden at start (March 25.2003)

0.54 A wye-termination component added. It connects the phases in a wye (star).
        A bug in generating the lines of parallel feeders for the EMTP *.dat-file corrected
        (But who simulates parallel feeders? :-) (Feb 21, 2003)

0.53  A per-unit calculator added, to convert per-unit impedances to ohms  (Jan 31, 2003)