The Overcurrent test module is used to automatically test the performance of protective devices that implement any combination of the 50, 50N, 51, 51N, 67, 67N, 46 and 49 protection functions. It also includes tests of operating values, and the external scheme tests related to these protective functions.

The module's functionality is distributed in the following sections:
 

Technical data

General parameters that affect all the tests contained in the Overcurrent module, such as: work with primary values, elements used for phase‐ground faults, ground CT data, sensitive ground CT data, Current, time and angle tolerances, directional settings, grounding characteristics and transformer connection.

Element list

The test module supports any number of phase, neutral, negative sequence, ground and sensitive ground elements. Different element characteristics can be selected, added and activated in the Element List, and different settings can be adjusted for each one. A Graphical View of the Relay curve is available for Non Directional and Directional Relays (Forward Curve, Reverse Curve and Operation/No Operation zone view)

Characteristics Template

Access to the edition of the different inverse time characteristics that Roots contain. Groups of pre‐defined Characteristics are available depending on specific equations (IEC, IEEE, ANSI, U.S.), user‐defined formulas, and curves in tabular form. Each one can be edited through modification of the associated variables. The user can also easily create new curves from scratch.

Test List

Multiple tests can be selected and attached to the device under test from a wide choice of test types including scheme‐oriented tests like reclosing or CB failure: Click Sequence, Pick up/drop out, Reclose, Cold Load, SOTF (Switch On To Fault), I2/I1 Ratio, Breaker Fail, Fuse Failure, SOL (Selective OC Logic), Reset Time.

Test Screen: with flexible access and configuration of the various test elements:

• Test Settings (prefault, fault and postfault)
• Test Points: Table of test points for each Fault type loop with the set values. With several methods to define and insert test points, individually, interactively clicked right onto the characteristic’s drawing or a number of time‐saving tools can be used to automatically generate series of test points, supporting separate or multiple fault loops selection (A‐N, B‐N, C‐N, A‐B, ABC, etc)
• Test Graph of the protection element: For directional relays, the graph shows three views, time curve for forward and backward faults, and an angular view, indicating the operating area by colors.

• Phasor Graph: Allow to view the phasor diagram of every point being tested.
• Hardware Settings: map the MENTOR 12    I/O and power connections to the relay, configuration of operating options in MENTOR 12 for Binary I/O (Relay/Open Collector, NO, NC, Dry/Voltage)
• Report and Report Configuration: Automatic report generation with user selection of data to be shown. The report can be produced in PDF format or other data interchange like XML. Reports are saved along with the results in the database.
• Test execution: Automatic sequential injection of test settings for every test point, comparing the operating time measurement with the allowable current and time tolerances in technical data, assessing the result as correct or incorrect and printing it both in the test point table and the test graph. The test sequence can be stopped at any time by the operator, and then resumed from the first non‐tested point. The user may also decide to reset the tested points and restart the entire test from the beginning, or to repeat the test only for a selection of the points in the list without affecting the other points.

Click Sequence

This shot test offers the easiest way to check the relay’s settings against the geometrical representation of its protective characteristic, through the running of a sequence of test points.
 

Pick up/drop out

Test for finding the pickup and dropout values of the active protection elements in the relay under test.
 

Reclose

This test allows the verification of the relays reclose function with any number of reclosing cycles, through the generation of reclosing sequences, and any combination of the elements settings for each reclosing cycle.
 

Cold Load

Test to evaluate the performance of protection devices that support the cold load function, through the generation of the necessary states, testing the capacity of the device to vary its normal overcurrent settings during the cold load period.

SOTF (Switch On To Fault)

Test to evaluate the performance of the relay during a SOTF condition. The user interface is designed so that the user can vary the position of the fault and the moment on which it happen. It also allows analyzing the behavior of the function related with the Recloser and the temporary acceleration of the overcurrent protection elements during the SOTF action time.
 

I2/I1 Ratio

This test allows the user to evaluate the performance of those relays that generate alarms or trips when a certain level is reached by controlling this relationship. The user can generate faults with the I2/I1 ratio desired and evaluate the performance of the alarms and/or associated trips.
 

Breaker Failure

Test to evaluate the behavior of the CB failure protection function. The user easily adjusts the desired conditions of the breaker failure settings (stage 1 and stage 2) and the software automatically generates the necessary states to perform the CB Failure Scheme, in different situations such as CB Failure Delay, CB Failure minimum phase current or CB Failure minimum ground current.

SOL (Selective Overcurrent Logic)

Test to verify the correct logic behavior of the protective devices on signal reception with forward faults and reverse faults, and the capacity of the protective device to selectively operate or change adjustments depending on signals received that are activated by request of other located devices in one direction or another.
 

Reset Time

This test allows checking the operation of the reset times used by mean of setting different test conditions. Induction electromechanical relays have inherent reset time delay. When a static or digital relays need to be coordinated with an upstream electromechanical, is convenient to use reset timings to ensure coordination. Another situation where reset delays are used is to reduce the clearance time in intermittent faults situations.