Programmable Variable Sources

Programmable variable sources (PVS) allow the user to set their own times and durations in some models. There are two types of PVS: a variable voltage source and a variable current source. As with the other sources discussed previously, the voltage source has a series-connected RLC impedance, and the current source a parallel-connected RLC impedance.

The RLC impedance elements can be connected either in series or parallel, and at least one of the RLC values must not be null. Figure 4 - 6 shows the icons and the diagrams used to represent the programmable variable voltage sources and the programmable variable current sources.

Properties: Represent programmable current or voltage sources

Features:

• The voltage source always has a series-connected impedance
• The current source always has a parallel connected impedance

Parameter Description

The control panels for the parameters of both sources each have three pages. The first pages of both versions have slight differences. Pages 2 and 3 are identical in both versions. Hence, only the control panel of the voltage source will be shown. Figure 4 - 7 shows the first page of the control panel for a programmable voltage source. This page contains the definitions of the general parameters. The load flow parameters, the SI and PU buttons and the base values (voltage, power, and frequency) are not present in the current source control panel.

General Parameters (Control Panel - Page 1)

The general parameters define the steady-state of the sources. This is the initial state before a variation sequence and the state found after the sequence.

RLC connection = Series (series R, L, C) or parallel (parallel R, L, C);
SI or pu units (voltage source only):

• SI: Specifies the values of the RLC elements, the voltage, and the frequency in international units (Ohm, Henry, Farad, Volt, and Hertz);
• PU: Specifies the values of the RLC elements, the voltage, and the frequency in PU (per unit);

Base values (voltage source only)

Here is how to input each sequence.

Source Control (Control Panel - General)

• Source status (Enable/Disable): To enable or disable the source;
• Starting mode (Slow/ Fast):
  • If Fast, the source is immediately activated or deactivated. Figure 4 - 5 (a) shows what happens when the source is activated in normal mode.
  • If Slow, when the source is activated, the amplitude of the source increases linearly from zero to the steady-state value. When the source is deactivated, the amplitude of the source decreases linearly from the steady-state value to zero. Figure 4 - 5 (b) shows the behavior of the source when it is activated in slow mode.

Synchronization (None/Internal): The synchronization of a source means that a programmed sequence of events will start with the rising front of a synchronizing signal. The synchronization is linked with the start of programming (Start/Stop) and the repetitive
mode. The operations must be initiated in ScopeView (see Figure 4 - 8) for the synchronization signals to take effect. See the paragraph on the repetitive mode (further down) for a description of the synchronization effects.

At the time this manual was written, the source could only be synchronized internally (POW). The option of synchronizing with an external signal is planned (External).

When Enabled, the programmed sequence of events will be repeated indefinitely according to the following conditions:

Programming status (Enable/Disable): If Enabled, the programmed sequence of events is displayed in the windows where HYPERSIM® was launched.

ScopewView Acquisition Parameters

Load Flow Parameters
(Voltage Source Only)

Timed Variation Programming (Control Panel - Timed variation)
Timed variations allow users to program sequences of events affecting the steady-state of the source, as defined by the settings for the amplitude, phase, frequency, and DC component on page General of the control panel.
It is possible to vary the amplitude, phase angle, frequency, and DC component of the source. These variations can be in modulation form (sinusoidal or random), step, ramp, or staircase. It is possible to execute some variations simultaneously. For example, the amplitude and frequency of a source can be made to vary in the same period of time. It is also possible to apply simultaneously a modulation and a ramp.
The activation of the variations is controlled by the Enable/Disable buttons on the page Timed variation of the control panel. Enable allows the execution of the variations, while Disable prohibits the application of the variations, but the programming values are saved.

Modulations

Modulation induces a sine or random variation of the selected parameter. Sinusoidal modulation can be applied to the amplitude, the frequency or the phase angle of a source, but for only one of these parameters at a time. Random modulation only applies to the amplitude of the source. It is possible to program other events, such as steps or ramps during a source modulation.

The random modulation periodically adds or subtracts a constant value to the value to be modulated.
The choice of adding or subtracting is random and the probability of each is 50%.

Modulation types: Allows users to select the parameter to modulate

Parameters for the sinusoidal modulation:

Parameters for the random amplitude modulation:

• Amplitude: Value to add to or subtract from the quantity modulated.
• Frequency and phase: Not used.
• Timing: Start (B) and end (E) times of the modulation and period (t) (multiple of) time step between successive calculations of the random signal. This period (B/E/I) must be greater than the calculation step selected for simulation.

Example of amplitude modulation
In the General controls page (see Figure 4 - 7), enter the parameters as follows:

• Module: 1 V peak
• Angle: 0 deg.
• DC offset: 0V
• Frequency: 10Hz
• Phase sequence: Direct
• Source status: Enable
• Starting mode: Slow
• Programming: Start
• Repetitive: Disable

Note: This mode, when Enabled, leaves the program variation running forever after the first Synchronization signal received (from Scopeview). To stop it, you have to toggle the parameters Programming from Start to Stop.

Programming: Enable

Note: This parameter displays the timed programming in a table format in the HYPERSIM® terminal window.
In the Time variations page, enter parameters as follows:

• Select the Amplitude modulation type button
• Timed variations: Enable
• Amplitude: 0.5 Volts (Amplitude of the modulation)
• Frequency: 2 Hz (Frequency of the modulation)
• Phase angle: 0.0 deg.
• Timing: 0/2 s

Using Scopeview, look at the signals Vabc and Iabc at the source.
Use a Time length of 2.5 seconds and a sampling rate associated with the time step of the simulation.
You will see an amplitude modulation of 0.5 V over a 1 V signal, at a rate of 2 Hz on an initial frequency of 10 Hz, during a two-second time span.

Amplitude modulation results

Example of frequency modulation

In the General Controls page (see figure 4 - 7), enter the parameters as follows:

• Module: 1 V peak
• Angle: 0 deg.
• DC offset: 0V
• Frequency: 10Hz
• Phase sequence: Direct
• Source status: Enable
• Starting mode: Slow
• Programming: Start
• Repetitive: Disable

Note: This mode, when enabled, leaves the program variation running forever after the first Synchronization signal received (from Scopeview). To stop it, you have to toggle the parameters Programming from Start to Stop.
• Programming: Enable
Note: This parameter displays the timed programming in a table format in the HYPERSIM® window.
• In the Time variations page, enter parameters as follows:

• Timed variations: Enable
• Select the Frequency modulation type button
• Amplitude: 10 Volts (Amplitude of the modulation + and –)
• Frequency: 1 Hz (Rate of the modulation)
• Phase angle: 0.0 deg.
• Timing: 0/2 s

Using ScopeView, look at the signals Vabc and Iabc of the source.
Use a Time length of 2.5 seconds and a sampling rate associated with the time step of the simulation. You will see a frequency modulation of ±10 Hz over a 10 Hz signal (meaning a variation from 0 to 20 Hz), at a rate of 1 Hz, during a two-second time span.

Ramp/Step Generation
Step or ramp variations can be programmed independently for each of the source parameters (amplitude, phase, frequency, DC component). These variations can coincide with a modulation. Five buttons in the bottom section on Timed variation page of the control panel allow users to select the parameter to be changed. Each selection is independent and has its own list of parameters on the right side. The operation in steady state precedes and follows each variation unless an infinite variation (without any end time) was programmed, a case where the final value of the variation is kept until the interruption of the variations. Here is the list of types of variations shown in the control panel. 

Types:

• AC: for a variation of the peak amplitude of the source.
• DC: for a variation of the DC component of the source.
• Phase: for a variation of the phase angle of the source.
• Frequency: for a variation of the source frequency.
• Sequence: to change a sequence.

Parameters

These parameters describe how the selected variables by typeset parameter will change in time. For example, the AC amplitude, DC component and source phase variations are described in the following fields: Amplitude, Operation Timing and Phase. Each of these fields is a list of specifications whose elements are separated by commas. All the lists of a variation type must have the same number of elements. Moreover, each element of a list is linked with the elements in the same position of the other lists. The input format of the values in the lists is described below:
Amplitude

Specifies both the amplitude and the type of variation. Each element of the list corresponds to a variation and consists of one to three numbers (initial value, final value and increment), separated by /, following the variation type required. Here is the correspondence:

• B,...Initial value only: step variation
• B/E,...Initial value and final value: ramp
• B/E/I(,...The initial value, final value, and increment: staircase.

Each element in the list must have a corresponding element in the Operation Timing and Phase lists.

Timing

Specifies the start and end times to apply the variations. Each element consists of two numbers separated by a/, depending on the case. The first (B) specifies the start of the variation in seconds. The second (E) specifies the end of the variation in seconds. Normally, both times must be entered and are compulsory for ramps or staircases. It is possible to specify only the start time (omit the /) for a step that keeps its value indefinitely. Each element in the
list must have a corresponding element in the Amplitude and Phase lists.

Phase

Specifies to which source phases the variations must be applied. Each element in the list designates a certain number of phases. These are simply the characters A, B and C, juxtaposed, if one wants to apply the variation to phases A, B or C. To set only phase A,
the element in the list will be..., A,... To set all the phases, the element will be..., ABC,... Each element in the list must have a corresponding element in the Amplitude and Operation Timing lists.

Frequency

The value of the frequency is specified in the same way as the Amplitude.
However, the frequency variation always applies to all the phases of the source.

Sequence

List of types of sequences.
Example of Ramp and Step generation.
First example: The peak voltage in steady-state of a source is 100 kV and the user wants to increase it progressively to 125 kV over a period of 0.3 seconds after a delay of 0.1 seconds. The delay is calculated from a starting point which depends on the synchronization mode of the source (refer to paragraph F in Source Control). The variation applies to all phases.

• Enable the AC ramp/step button to enter in the fields the following variation parameters:
• Amplitude: 100000/125000
• Timing: 0.1/0.3
• Phase: ABC

Suppose the user wants to change the base voltage source according to the following model:
A ramp applied to the source amplitude with the following parameters:

• Start time: 0.1 s
• End time: 0.3 s
• Initial amplitude: 0.0 s
• Final amplitude: 600 000 volts

Another ramp applied to the source amplitude with the following parameters:

• Start time: 0.35 s
• End time: 0.45 s
• Initial amplitude: 1 000 000 volts

For a DC components step with the following parameters:

• Start time: 0.2 s
• End time: 0.3 S
• Amplitude: 200 000 volts
• These events are programmed as follows (assuming that all the phases are active):
• Enable AC and DC ramp/step and fill in the fields with the corresponding parameters:

AC

• Amplitude: 0.0/600000, 1000000/100V
• Timing: 0.1/0.3,0.35/0.45s
• Phase: ABC

DC

• Amplitude: 200000
• Operation timing: 0.2/0.3
• Phase: ABC

Note: The values in the fields to program the wave amplitude (AC) were aligned vertically to set apart both events occurring at times that do not coincide. Events affecting the same object cannot coincide. However, two events affecting different parameters of a source, such as the wave and DC components amplitude, can coincide without any problem.

Figure 4 - 13 shows a section on the second page of the programmable voltage sources control panel describing the preceding programming.

Example

• Enable AC and DC ramp/step and fill in the fields with the corresponding parameters:

AC

• Amplitude: 1/10V
• Timing: 0.5/2s
• Phase: ABC

Programming Harmonics (Control Panel - Harmonics)

This function allows users to add harmonics to the waveform of the source. Programming harmonics consists in defining the harmonic content, specifying the times at which the harmonics will be added and the general activation of the harmonics.
The fields of the parameters allowing to define the harmonic content are identified in the General parameters section with the following labels (See figure 4 - 13):
Harmonic Numbers

This is the list of the numbers for the required harmonics.
The harmonics are numbered from 1 (the fundamental) to 50. It is not necessary to specify the fundamental (1). The list consists of elements separated by commas. Each element can be an integer or a compact notation B/E/I allowing to specify a succession of harmonics, starting with the first (B) to the last (E) with increments I. It is possible to repeat the same harmonic number.
Amplitude

The list of amplitudes relative to each harmonic. The amplitude of each harmonic is relative to the fundamental (amplitude 1). It is specified by a number Ar so that 0.0 < Ar <= 1.0. The list must contain the same number of elements as the list
of harmonic numbers. The elements are separated by commas and each can be a number between 0.0 and 1.0 or the compact notation B/E/I allowing to specify a succession of equidistant amplitudes.
Angle

List of the phase angles for each harmonic.
Enter here the required phase angle displacement (outphasing) relative to the fundamental. This outphasing must be specified in degrees. The list must contain the same number of elements as the list of harmonic numbers. The elements are separated by commas and each element can be an angle or the compact notation B/E/I allowing users to specify a succession of equidistant angles.
Sequence

List of specifications of the sequences (positive, negative, zero and per phase) for each harmonic.

Each harmonic must be specified in positive, negative, zero sequence or per phase. The list provides the sequence to use for each harmonic. It can be empty if all the harmonics are in positive sequence (the most common case). If not, it must contain the same number of elements as in the list of harmonic numbers. The elements are separated by commas. Each element can be one of the following letters:

• D Harmonic is in positive sequence (0, -120, +120 degrees)
• I Harmonic is in negative sequence (0, +120, -120 degrees)
• H Harmonic is in zero sequence (0, 0, 0 degrees)
• P Harmonic applies only to some phases

Phase

List of phases to which apply the parameters per phase (list Sequence)
The Phase list must contain as many elements as there are parameters per phase (P) in the Sequence list. It can be empty if there are no parameters per phase. The elements are separated by commas. Each element can be formed by a concatenation of the letters A, B and C corresponding to the selected phases. The case ABC is programmed more simply by using the positive sequence (D).

The fields allowing users to program the injection of harmonics are at the beginning of the page.
There are two such fields:
Timing

List of enable/disable times - activation/deactivation.
This is a list of the time values whose elements are separated by commas. Each element can be a numerical value or a compact notation B/E/I for a series of equidistant values. The list must contain at least one element in order to generate harmonics.
Operating activation

List of activations:

This list specifies whether or not there is activation of harmonics. It is linked to the list of times and must contain the same number of elements. The elements are separated by commas. Each element can have the value 1 to activate harmonics
or 0 to deactivate. The minimum list must contain the value 1 in order to generate harmonics.
In this case, the generation of harmonics will begin at the time entered in the Operation Timing list and will remain active until the events programming is stopped by clicking the Stop button on the first page of the control panel.
The global activation of harmonic injection is done by clicking the Enable button on page 3. When Disable is selected, the source operates without harmonics. However, the programming of harmonics is saved and can be reactivated at any time.
Example of harmonic voltage source programming:

Synthesize an harmonic voltage source with the following parameters:
In the General Control page, enter the parameters as follows:

• Module: 1 Vpeak
• Angle: 0
• DC offset: 0 V
• Frequency: 10 Hz
• Phase sequence: Direct
• Source mode: Enable
• Starting mode: Slow
• Programming: Start
• Repetitive: Disable

Note: This mode when enabled, leaves the program variation running forever after the first Synchronization trig received (from Scopeview). To stop it, you have to toggle the parameters Programming from start to stop
Programming: Enable

Note: These parameters print the timed programming in a table format in the HYPERSIM® window.
In the Harmonics page, enter the following parameters:

• Harmonic number: 10
• Amplitude: 0.25pu
• Activation: 1, 0, 1, 0
• Timing: 0.1, 1, 1.1, 2 s
• Phase: ABC
• Angle: 0
• Sequence: D

Using ScopeView, look at the signals Vabc and Iabc of the source.
Use a Time length of 2.5 seconds and a sampling rate associated with the time step of the simulation. You will get a generation of 0.25 pu of the 10th harmonic in direct sequence over impose with the main signal of 10 Hz, and so between 0.1 and 1 second and also between 1.1 and 2 seconds.

List of Available Signals
At acquisition, the following signals are made available by the sensors:
• I (a, b, c)_label: Source current (A).
• VINT (a, b, c)_label: Voltage source (V).