LineDropout() Test Objective

Testplan Syntax

The LineDropout() function has the following syntax with the arguments described in the table below:

LineDropout(REF, LINE_RANGE, NOMINAL_VOLTAGE, NUMBER_OF_CYCLES, FREQUENCY)
LineDropout(REF, LINE_RANGE, NOMINAL_VOLTAGE, NUMBER_OF_CYCLES, FREQUENCY, OPTIONAL_PARAMETER_STRING)

parameter_name1=parameter_value1 parameter_name2=parameter_value2

Simulation Timing

DVM sets the timing parameters for the LineDropout() test objective based on values that you enter on the Line Surge/Sag page of the DVM Full Power Assist control symbol:

Delay before Dropout, Duration of Surge/Sag, Time to Recover, and Dropout Phase Angle.

In the OPTIONAL_PARAMETER_STRING and in the calculations below, these values are renamed as follows:

• NCYCLES1 = Delay Before Dropout
• NCYCLES3 = Time to Recover
• PHASE_ANGLE = Dropout Phase Angle

The duration of the Line Dropout is determined by the test objective argument NUMBER_OF_CYCLES.

The time delay is based on the following conditions and calculations. Typically the LINE_PHASEANGLE is set to 0, although in a 3 phase system only one of the three line sources will have a zero LINE_PHASEANGLE.

If LINE_PHASEANGLE is greater than 0, then

\[ \text{TIME_DELAY} = \frac{360 - \text{LINE_PHASEANGLE}}{360 * \text{FREQUENCY}} + \frac{\text{NCYLES1}}{\text{FREQUENCY}} + \frac{\text{PHASE_ANGLE}}{360 * \text{ FREQUENCY}}  \]

If LINE_PHASEANGLE is less than or equal to 0, then

\[ \text{TIME_DELAY} = \frac{\text{NCYLES1}}{\text{FREQUENCY}} + \frac{\text{PHASE_ANGLE}}{\text{360} * \text{FREQUENCY}}  \]

The pulse width and stop time are based on these calculations:

\[ \text{PULSE_WIDTH} =  \frac{\text{NUMBER_OF_CYCLES}}{\text{FREQUENCY}} \]

\[ \text{STOP_TIME} = \frac{\text{NCYCLES1} + \text{NUMBER_OF_CYCLES} + \text{NCYCLES3}}{\text{FREQUENCY}}\]

A special note about the input voltage source used for this test objective. The slew rate of the input line voltage during the line transitions is limited by the input source. Each AC source has a programmable filter and slew rate limiter - the combination of these two circuits will limit the rate of change of the input line voltage. Of course, if the surge phase angle is set to 0, 180 or 360, there is no instantaneous change in the input voltage, as the line source changes when the line voltage is zero.

Source and Load Subcircuit Configuration

The LineDropout() test objective sets the source and load subcircuits to the following:

Loads other than the output under test are set to the Resistive Load. All other sources are set to either the DC Input Source for DC sources or the AC Fixed Input Source for the AC input sources.

Measured Scalar Values

The LineDropout() test objective measures the following scalar values where {load_name} is the name assigned to each load, and {source_name} is the name assigned to each source.

Measured Specification Values

In the following table, {load_name} is the name assigned to each load, and {source_name} is the name assigned to each source.

Testplan Example

An example of the LineDropout() test objective taken from the AC/DC (1-input/1-output) testplan is shown below. This test objective configures the line to dropout for one line cycle with timing values set on the Line Dropout page of the Full Power Assist DVM control symbol. The Line Dropout duration (in line cycles) is the fifth argument to the LineDropout test objective.

Optional Parameter String

The following LineDropout() test objective uses the OPTIONAL_PARAMETER_STRING argument to set the line voltage to dropout for one line cycle, and sets the time delay before the dropout (NCYLES1) to 2 line cycles.

LineDropout(INPUT:1, HL, Nominal, F_Low, 1, NCYCLES1=2)

Test Report

You can view the complete test report in a new browser window here: LineDropout() Test Report. Below is an interactive link to the same test report.