Power System Description (PSD)

This short description gives you information on the following topics:

• Modelling a Power Distribution System with PSD
• Upgrading from an Older OSCOP P Version

 

 

 

 

 

 

 

 

 

 

 

 

Modelling a Power Distribution System with PSD

Procedure for creating a new project

The Power System Description (PSD) offers you three views of your data:

• In the Network configuration view, you create networks ("Voltage levels") and lines.
• In the Substation configuration view, you can parameterize substations and substation elements (busbars and feeders).
• In the Device configuration view, you can assign devices and measuring channels to your substation elements.

First of all, create your networks in the Network configuration view and make the appropriate settings.

Then change to the Substation configuration view to create your substations there. First enter the busbars within a substation. You must immediately assign a network (and thus a voltage level) to each busbar.

Then create the corresponding Feeders in the level below the busbars. Every feeder represents a measuring point in this model.

The feeders are required:

• for fault location.
  Feeders mark the end points (measuring points) of a line.
• for PowerQuality evaluations
  A feeder represents a SIMEAS Q or the corresponding channels of a SIMEAS R.

A complete feeder parameterization includes the assignment of measuring channels for current and voltage measurement. Configuration is possible, however, only if the respective devices are provided in PSD (see Parameterization the devices).

To be able to perform a fault location, you must parameterize the lines. This is done in the Network configuration view.

Once you have created a line below a network object, the line parameters can be entered. In doing so, you can choose between a single-ended or a two-ended fault location. In the case of a single-ended fault location, an optional parallel line compensation for double-circuit lines can be carried out (to do so, select the option Yes under the Double-circuit line).

A line can comprise of several sections with different impedances, for example, cable and overhead line. This is why PSD enables you to subdivide your line into several Segments with different characteristics.

Parameterizing the line sections

Various characteristic data of a line segment are required for fault location. Basically, it is a matter of impedance of the positive-sequence system, the earth impedance as well as the coupling impedance, as the case may be (if Double-circuit line has been set). There are several options for entering the impedances:

• Entry of the positive sequence system using
• R1' and X1', or
• X1 and angle ("Phi").
• Entry of the earth impedance matching using
• R0' and X0',
• the ratios RE/RL and XE/XL (RL = R1, XL = X1),
• the complex matching factor kL, or
• the complex impedance ratio Z0/Z1.

The input format is selected in the menu item Extras -> Options. To enter the coupling impedance, there is only one option with the ratios RM/RL and XM/XL. For the definitions of the individual values please refer to Appendix: Equation Symbols and Equations.

All impedances and matching factors are quantities per unit length (e.g., Ohm/km). Impedances referred to the primary side are required. You can choose between kilometres and miles as the unit of length. This setting can be made in the OSCOP P module Parameterize PC under the menu item Global -> Country settings -> Metric or US units. The setting applies to all OSCOP P modules.

If you change the input format or switch between kilometres and miles, values that have already been entered will be converted automatically.

You can enter the capacities in all input formats. The capacity values are calculated appropriately from the remaining impedances. We recommend the default setting (at least for overhead lines). If you want to enter the capacities explicitly, click on the corresponding value and overwrite the displayed text will be calculated with the value.

The equations for automatically calculating the capacities can be found in Appendix: Equation Symbols and Equations.

In addition to the line impedances, you can set several further parameters. The total length of the line is calculated from the lengths of the individual sections and is displayed in the general parameter table.

You can use the context menu to add further sections. To do so, click on the section number in the first column with your right mouse button. You can either create a new section with the preset values under Add segment or use an existing section as a template with Copy and Paste. The order of the sections can also be changed subsequently via the context menu.

Parameterizing the devices

At the moment, there is no option to create or parameterize the devices directly in the PSD configurator. For this purpose, you have to use the other OSCOP P modules (Parameterize PC for creating devices and Parameterize Devices for configuring devices).

Only the device parameters that are required for parameterizing the fault location are displayed in the PSD model. Basically, these are assignments of devices and measuring channels to other substation elements.

Notes on How to Configure Assignments

Measuring channel assignment for fault location

• You must define channels both for voltage and current measurement for every feeder.
• Here you can assign the following devices/device components to the feeder:
• Channel group of a SIMEAS R
• DAU of an OSCILLOSTORE
• The assignments made here are applicable only for fault location. However, you can assign several devices to the feeder, e.g., an additional SIMEAS Q for measuring PowerQuality data. These additional assignments are configured in the Device configuration view.
• You can also measure and assign the voltage for all feeders centrally at the busbar.
• General restrictions:
• The voltage and current channels for fault location must always be assigned to the same device.
• Channels that have already been assigned to another feeder can no longer be assigned (if necessary, delete the old assignment first).

Assignment between line and feeder

• The lines must be assigned in the Network configuration view.
  Regarding the assignment, it must be differentiated between the two-ended fault location and the single-ended fault location with parallel line compensation.

Two-ended fault location

• You can assign a feeder to each of the two line ends. The feeders are here referred to as Left feeder and Right feeder. Please note for line orientation that the section on top of the section table has been assigned to the left feeder.
• You can also assign only one line end to a feeder if necessary. In this case, fault location is performed from one side only. However, the results of single-ended fault location are far less accurate than that of two-ended fault location.
• General restrictions:
• Both feeders that you assign to one line must be in different substations.
• Both feeders must have been assigned to the same network that the line has also been assigned to. (A feeder is assigned to a network indirectly via the busbar.)

Single-ended fault location with parallel line compensation

• To assign the feeders of the double-circuit line, use the fields marked Feeder 1 and
  Feeder 2.
• In order to carry out the compensation, both feeders must be assigned.
• If a single-ended fault location without compensation shall be carried out, select the option No in Double-circuit line and then assign the Left feeder only.
• Both feeders of the double-circuit line must be installed at the same substation and they must be part of the same network.

Assigning a substation element (feeder or busbar) to a device or a device component

• In the Device configuration view, you can very flexibly assign devices and device components to your substation elements.
• The following devices can be assigned as an entity:
• SIMEAS Q
• Protection devices
• COMTRADE archive
• You can assign the following device components:
• DAU (only with OSCILLOSTORE)
• Channel group (only with SIMEAS R and SIMEAS R-PMU)
• Channel
• Several devices or device components can be assigned to a substation element, e.g., one for fault location and another for PowerQuality evaluation.
• If you do not want to assign a complete channel group to a feeder but want to assign the channels individually, you can use the Device configuration view.

Upgrading from an Older OSCOP P Version

When installing OSCOP P, all the data from your old OSCOP P database is transferred. The database including all configuration settings is converted automatically to the new format.

The fault locator configuration ("V2 diagnostics") of an old OSCOP P version is compatible to the PSD configurator.

The following configuration elements are transferred automatically from an old project:

• Device configuration
  The device parameters including the channel information are transferred one-to-one to the new project.
• Network configuration
  Networks in this form did not exist in OSCOP P so far, only indirectly as voltage levels. A network object is created for each individual voltage level in PSD. The name results from the voltage value, e.g., 110_kV.
• Line configuration
  The lines and line parameters, especially the impedance values, are transferred automatically.
• Substation configuration
  Substations (so far referred to as subsystems) are transferred automatically.
• Feeder configuration
  The feeders are directly transferred from the old data; in contrast to previous OSCOP P versions, the feeders are not assigned directly to a substation but always via a busbar. The busbars required for this arrangement, that did not exist in the old project, are created automatically. The names are generated according to the pattern Busbar1, Busbar2 etc.

After you have transferred an old project, check the configuration data that has been entered automatically and complete it insofar as this is necessary.

• Line sections
  Check whether the sections have been transferred correctly and in the correct order. Check all impedance values exactly and compare the values with your plant charts. The accuracy of the fault location calculation greatly depends on the correctness of the parameterized line impedances.
• Feeders
  Check the substation configuration and add missing parameters.
• Networks
  In the old configuration, networks did not yet exist as independent objects. When old data is transferred, the network objects are generated from the information on the voltage levels. If necessary, adapt the network structure to your specific network model.
• Assignments
  The assignments between the various device and substation components are transferred as far as possible. Check and complete all assignments.