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Data

Introduction​

The Data Node imports data from an external file.

This Node is typically used for the following:

  • Overlaying dynamic simulation results from power systems software (e.g. PSS®E, PSCAD™) with real data from Hardware-In-the-Loop (HIL) testing or on-site commissioning.
  • Plotting dynamic simulation results from power systems software which is not currently supported.
info

Currently, the Data Node only supports comma-separated values (csv) external input files.

User inputs​

Select data​

Input file name​

Defines the input directory and file name of the external input file, including the .csv file extension.

Example:

s52513_Qref_step_test__results.csv

Input file range​

Defines the methodology for importing data x-axis (i.e. index) values from the data. Options:

  • All: All x-axis (i.e. index) values are imported from the external input file (i.e. x-axis: Min [index] = 0 and x-axis: Max [index] = Max no. of rows in file).
  • Defined range: A subset of x-axis (i.e. index) values are imported from the external input file. You must manually select values of x-axis: Min [index] and x-axis: Max [index].

x-axis: Min [index]​

Defines the first x-axis (i.e. index) value imported from the external input file. Only appears if Import type is set to Defined range.

x-axis: Max [index]​

Defines the last x-axis (i.e. index) value imported from the external input file. Only appears if Import type is set to Defined range.

Example: Import data from an external csv file which was generated by a PQM meter which had a sampling rate of 1 ms. The file was recording data for 30 seconds and therefore the csv file has 30,000 rows. However, you only want to import data from the last 10 seconds of this file.

x-axis: Min [index]
20000;
x-axis: Max [index]
30000;

Process data​

X-axis shift​

Auto-align​

The auto-align feature automatically shifts the imported data in the x-axis direction, such that a single column of the imported data aligns with a single channel from a connected Node. This feature is typically used when overlaying dynamic simulation results from power systems software (e.g. PSS®E, PSCAD™) with real data from Hardware-In-the-Loop (HIL) testing or on-site commissioning.

The images below show an active power step with and without auto-align enabled.

auto-align-false
danger

When using the auto-align feature, we recommend aligning on the channel which had the biggest change over the dynamic simulation. For example:

  • If you are simulating a fault, align on the voltage channel.
  • If you are simulating active power step(s), align on the active power reference channel (if available) or otherwise use the active power output channel.
Column​

Defines the name of the column from the external input file which is being used in the auto-align feature.

Channel​

Defines the name of the Channel from a connected Node which is being used as the 'anchor' in the auto-align feature. This Channel is often output from dynamic simulation results from power systems software (e.g. PSS®E, PSCAD™). The image below shows a typical Flow structure when using the auto-align feature.

auto-align-example-flow

Actions​

Defines the Commands which are applied to the imported data.

Supported Commands:

  • PROCESS: Processes all values in a column of the imported data.

Define outputs​

Outputs​

Defines the outputs from the Data Node. The outputs defined here may be used later for plotting and/or further analysis.

Supported Commands:

Outputs Description​

Defines a short description of the data. This description will appear in the legend of any plot of the data originating from this Node.

Example:

Description here!

example from a Plot Node PDF output showing how the 'Description here!' text is added

Advanced​

Advanced Parameters​

Advanced Parameters allow users to configure test details which are not commonly used. Advanced Parameters are often specific to each Node type.

Each line represents a new Advanced Parameter and is entered as a=b format, where a is the name of the Parameter and b is the corresponding value. All Advanced Parameters are set to their default values if they are not included in the Advanced Parameters field.

Example: Set Advanced Parameter, sample.parameter to a value of 5.

sample.parameter=5

API Reference​

This section details the Commands and Advanced Parameters specific to the Node.

note

If a column name in the external input file contains spaces, please reference this name by replacing the spaces with _. For example, if a column name in the external file is my Ppoc. Please set COL=my_Ppoc.

Actions​

PROCESS | Process column​

PROCESS, COL=, [VALSCALE=, VALOFFSET=]

Processes all values in a column of the imported data. All subsequent Commands will use the processed data. This feature is typically used when data in the external input file is not in the desired units (e.g. voltage is expressed in Volts, not p.u.).

Arguments:

  • PROCESS
  • COL (str): Column name in the external input file.
  • VALSCALE (float)[Optional]: Multiplicative scale applied to the column values. scaled_value = (unscaled_value + VALOFFSET) × VALSCALE. Defaults to 1.
  • VALOFFSET (float)[Optional]: Additive value applied to the column values. scaled_value = (unscaled_value + VALOFFSET) × VALSCALE. Defaults to 0.

Example: You have an external input file named my-real-data.csv. You wish to import active power from a column named P_POC in this file. However, the units in the external file are expressed in kW not MW, as you desire. Define the required Command to process this column of data.

PROCESS, COL=P_POC, VALSCALE=0.001

Outputs​

OUTPUT | Output value(s)​

OUTPUT, COL=, [VAL=, VALSCALE=, VALOFFSET=, AT=], NAME=, [LEGEND=]

Outputs all values from a column in the imported data. Use the AT= Argument to output a single value at a specified time.

Arguments:

  • OUTPUT
  • COL (str): Column name in the external input file.
  • VAL (str)[Optional]: The type of output channel. Specifying the correct value for the output channel will result in more accurate auto-scaling for connected Plot Nodes. Options:
    • VAL=PQS: Active power [MW], reactive power [MVAr] or apparent power [MVA].
    • VAL=V: Voltage [p.u.].
    • VAL=F: Frequency [Hz].
    • VAL=ANGLE: Angle [degrees].
    • VAL=I: Current [p.u.], active current [p.u.] or reactive current [p.u.]
    • VAL=BINARY: Binary outputs, such as LVRT/HVRT trigger flags.
    • VAL=PF: Power factor [unitless].
  • VALSCALE (float)[Optional]: Multiplicative scale applied to the output value(s). scaled_value = (unscaled_value + VALOFFSET) × VALSCALE. Defaults to 1.
  • VALOFFSET (float)[Optional]: Additive value applied to the output value(s). scaled_value = (unscaled_value + VALOFFSET) × VALSCALE. Defaults to 0.
  • AT (float)[Optional]: Time in the data to extract a single value. The extracted value is taken from the first time step after this time [seconds]. If the AT= Argument is not provided, then the output is a time-series channel of values.
  • NAME (str): Output name. Output names must be unique within a Node.
  • LEGEND (str)[Optional]: Subplot legend name. Default value is no legend name.

Example: You have an external input file named my-real-data.csv. You wish to import all the time-series data from a column named P_POC in this file and later overlay this data with results from a PSS®E Dynamic simulation. The Internode Variable named should be i_real_data_Ppoc. Define the required output Command.

OUTPUT, COL=P_POC, NAME=i_real_data_Ppoc

Example: You have an external input file named my-real-data.csv. You wish to import the initial active power value from a column named P_POC in this file to initialise a PSS®E Static simulation. The Internode Variable name should be i_real_data_Ppoc_initial. Define the required output Command.

OUTPUT, COL=P_POC, NAME=i_real_data_Ppoc, AT=0

Advanced Parameters​

high.resolution.align​

  • Description: Only applicable if auto-align enabled. If Yes, switches to a higher resolution alignment algorithm which is much slower but can produce better alignment between the imported data and the connected Node's source channel. If No (default), a lower resolution alignment algorithm is used which is much faster, but may not align as well.
  • Type: str
  • Units: N/A
  • Default: No
  • Range: N/A
high.resolution.align=value

experimental.alignment.algorithm​

  • Description: Only applicable if auto-align enabled. If Yes, switches to a new alignment algorithm which is still in development. This new algorithm will attempt to align as much data as possible by penalising extrapolation, thereby producing better benchmarking alignment than the default algorithm under certain circumstances. If No (default), the gridmo default alignment algorithm is used.
  • Type: bool
  • Units: N/A
  • Default: No
  • Range: Yes, No
experimental.alignment.algorithm=value