Impedance element evaluations using automatic testing modes
In addition to the base functionality of the Distance test module, Advanced Distance provides the following advanced functionality:
- Search and Check tests of the zone reaches
- Test settings relative to zone reaches and line angle (“relative shots“)
- Constant source impedance test model
- Load current superimposition
Shot test, Search test, and Check test
In a Shot test, single test points are added to a test point table and are automatically processed (see Distance test module).
In a Search test, zone reaches are determined automatically. Zone transitions are searched along search lines specified in the impedance plane, using an optimized algorithm. It is possible to define a series of search lines. All defined search lines are stored in a table for automatic processing.
In a Check test, test points are automatically set at the tolerance boundaries of zones. The setup is done with test lines (check lines) similar to a search test, but test points are only set at the intersections of the check lines with the zone tolerances. The Check test is an efficient overall test of the relay with minimum testing time. This gives a quick verification of whether the specifications are met, particularly for routine tests.
Adding test points and test lines to the tables is possible in a variety of ways. Parameters can be precisely defined by numerical inputs, or specified directly in the characteristic diagram. A magnetic cursor supports the choosing of meaningful values. Mouse commands, context menus and keyboard shortcuts facilitate data input.
A test in Advanced Distance can have any combination of Shot, Search, or Check tests. At test execution, the whole test settings are executed sequentially. This versatile system offers a wide range of testing possibilities. Using this, it is easy to comply with most different testing philosophies and regulations.
Relative test definitions
A powerful feature is the possibility to make test point definitions relative to the nominal characteristic of the distance relay (e.g. 90 % of zone 1, 110 % of zone 1, 90 % of zone 2,…). Test points are not entered in absolute R, X, Z, or angle values, but are referred to zone reaches and the line angle instead. This feature allows the creation of re-usable test templates, which adapt themselves to the actual relay settings.
Constant source impedance model
Besides the constant test current and constant test voltage models, Advanced Distance provides the constant source impedance test model which is useful in special cases where parameters such as SIR (Source Impedance Ratio) are important.
To verify special behavior of certain relays which occurs only when a pre-fault (load) current is present (e.g. accelerated tripping performance), a load current can be superimposed.
Testing multiple fault loops in one test module
Advanced Distance provides special support by performing the tests for multiple fault loops (L-N, L-L and L-L-L) within one test module. For all test modes (Shot, Search, Check) multiple tabs are provided with a separate test point table for every fault type. Test settings can either be entered fault-loop-specific or defined simultaneously for multiple fault types.
Distance Characteristic Guesser
If the nominal characteristic of a relay should be unknown or the actual characteristic shape is to be documented, a guesser function allows the automatic generation of an approximated characteristic based on the results of a Search and/or Shot test. The calculated characteristic can be saved and further used as the relay's nominal characteristic.
Multi-windows user interface
The user interface can be configured individually, using the following elements:
- Test View
This view holds the test point tables for the Shot, Search, and Check tests and the impedance plane. Test definitions are made in this view. During and after the test execution, this view displays the results numerically in the tables and graphically in the impedance plane.
- Z/t Diagram
This view shows the graded trip time curve over the impedance along a certain line. The actual line is determined in the impedance plane or by a selection in the test tables. It is also possible to define test points and to view the assessments in the diagram.
- Phasor diagram
The phasor diagram shows the phasors of the voltages and currents, both for the phase quantities and the sequence components. The corresponding numerical values are displayed in the attached table.
- Time Signal View
After a completed shot the voltages, currents, and binary signals are shown in this view. This is useful to perform more detailed investigations (e.g. time measurements using cursors)
This module is part of the Test Universe software. For more information please refer to the Test Universe website.