master:thd parametersPSCAD Harmonic Distortion Calculator

Every parameter of the PSCAD Harmonic Distortion Calculator (master:thd): 3 names, with the unit, the default and the meaning PSCAD gives each one. Copy a name into parameters().

What master:thd is

The on-line harmonic distortion calculator. It works on the signals of an on-line frequency scanner during the run; a script can also take THD from a recorded waveform afterwards, which is what the Builder's Harmonic distortion block does.

Definition
master:thd
PSCAD name
Harmonic Distortion Calculator
Category
Meters and output
Parameters
3, in 1 group
Read from
PSCAD 5.0.0, 2026-11-07

Most used master:thd parameters

ParameterUnitDescription
Size·Number of Harmonicsnumber of harmonics
Mode·Output Mode:per unit or percent

Read and write master:thd in Python

import mhi.pscad

pscad = mhi.pscad.connect()              # the PSCAD that is open; launch() starts one
project = pscad.project("my_case")       # a case loaded in the workspace

for comp in project.find_all("master:thd"):   # the exact definition, namespace first
    params = comp.parameters()           # every parameter, as PSCAD holds it
    print(str(params["Size"]))           # Number of Harmonics

comp = project.find_all("master:thd")[0]
comp.parameters(Size="15")               # a Choice is written as its symbol
  • A parameter is named exactly as in the table, letter case included: parameters() gives every one of them in a dictionary, and a name the component does not have is refused.
  • A value that carries a unit comes back as a number whose unit is only in its text, so read it as text first (str(...)) or the unit is lost. PSCAD keeps a written unit as it is given: "2500 [mohm]" stays in mohm.
  • A Choice is read and written as its symbol (the capitals in "Written as"), not as the words PSCAD shows in the dialog.
  • find_all() takes the exact definition only. A wildcard or a bare name without master: comes back empty; the Builder's px_find walks the pages for those.

The Builder's runtime does the same with the unit handled for you: px_get(comp, "Size") and px_set(...), which also records the old value so the case is put back at the end. Getting started shows them.

Configuration

ParameterUnitDefaultDescription
ModeChoice·PER_UNITOutput Mode:Written as PER_UNIT (per unit), PERCENT (percent)
NameText··Name for IdentificationEnter a name for identification
SizeChoice·7Number of HarmonicsWritten as 7, 15, 31, 63, 127, 255, 511, 1023

Related

← master:cinj Harmonic Current Injection · master:phasorimp Harmonic Impedance →