Test View Window
As mentioned previously, one of the windows in “Overcurrent” room is “Test View”. This window comprises of 5 tabs of “Shot Test”, “Pick Up-Drop Off”, “Setting”, “Trigger” and “Binary Output”. Specifying the test points is done in “Shot Test” and “Pick Up-Drop Off” tabs.
In “Shot Test” tab, you can select fault type and the points for the test and after the test is performed, you can view the results of the evaluation. In this tab, in “Test Point” section the fault current and in “Fault Type” section the fault type are determined. In “Test Point” section, the fault current and the angle between current and voltage are specified in “I Test” and “Angle” fields respectively. Note that this angle is only useful for performing “Directional” tests.
If you want to specify the fault current in terms of a coefficient of “CT” nominal current or “Pick Up” current of one of the specified “Stages”, you need to check “I Test Relative” option and specify the coefficient in “Factor” field and then, from “Relative to” drop list select the base current to specify the fault current. This base current can be a “Pick Up” current of one of the “Stages” or “CT” secondary nominal current. After specifying the test current, you need to select the fault type from the standard faults available in “Fault Type” section. These faults include different types of phase to earth, two phase, three phase, inconsistency, “3I0” and “L1”, “L2” and “L3” faults.
To better understand “L1”, “L2” and “L3” faults, suppose that in a line, there is a transformer with a delta connection on the first side. When a fault occurs in the secondary side, the fault phase corresponding current will flow in the first side and this fault current is provided by other phase or phases. “Negative Sequence” or inconsistency faults test is available by selecting “I2”. Since relays detect inconsistency fault by using the value of negative sequence current, by selecting this type of “Fault Type”, the entered fault current will merely be negative sequence current. “3I0” fault is useful for “Earth Fault” in “Summation” mode while “L-E” fault is useful in “Measuring” mode.
By clicking on “Add”, the selected test point is added to the table in this window. Regarding the test points, note that if you check the "I Test Relative to" option and make the test stream dependent to a parameter and "Add" that point, that test point is always dependent on the value of that parameter and by changing the value of that parameter, the amount of the test current also changes. To clear the subject, check the "I Test Relative to" option and the test current is defined twice the rated current, and this point is added to the test table. Now if you change the rated current to 5 amps you will see that the test current changes from 2 amps to 10 amps. By selecting one of the rows and clicking on “Insert” option, the selected row is repeated in the table and by clicking on “Remove” option, the selected point is removed. Also, by selecting “Add to” option, it is possible to copy point or points selected for one of the “Fault Types” to another “Fault Type”. By clicking on “Remove All” option, all test points entered in the table will be removed.
By clicking on “Sequence” option, “Sequence Test Points to” page opens where it is possible to specify test points with equal steps. In “Current Data” section, steps are created in direction of the range. By selecting “Current” in “Sequence Type” field, current steps are directly entered in terms of ampere and by selecting “Factor”, the current is entered in terms of the parameter selected in “Relate to” field.
In “Start Value”, “End Value” and “Step Size” fields start point of the current point, end point of the current point and steps are specified respectively. For example, “Factor”, “Pick Up” current of the first “Stage”, 2 times, 6 times and half of “Pick Up” current are selected as values for “Sequence Type”, “Relate to”, “Start Value”, “End Value” and “Step Size” respectively. You can see that “Step Count” which is the number of current steps or test points equals 9.
Moreover, in “Angle data” section, the information related to start angle, end angle and step size are entered in “Angle data”, “Start Value”, “End Value” and “Step Size” respectively. Here 30, 45 and 5 are entered as these values. In “Step Count” field, the number of current steps are specified which is 4 points. In “Total Shot Count” field, the sum total of points is calculated. This value shows that each point in all 4 specified angle “Steps” enters test table with a specified current range. After selecting the “Fault Type” of “L1-E” and “L2-E” and confirming them, you can see that these points are added to the test point table.
If the performed test has “Failed” points, by selecting “Clear All Failed Tests” option, it is possible to clear all these points from the table of this section. In “Detail” section, the information related to “Trip” nominal time, the allowed operation time range, actual time and test point evaluation are entered in “t nom”, “t min” and “t max” fields, “t act” and “Stage” field respectively. The test points are entered with detail in the table at the bottom of the page. The details include test evaluation, test current, test point angle, whether the test is “Relative” or not; if it is “Relative”, the base coefficient and parameter, nominal time, operation time, fault measure in terms of percentage and seconds and the minimum and maximum operation times are entered. Also, if you wish to add a comment about any of the test points, you can use the “User Comment” cell. At the end of this page, it is possible to select test points table from different “Fault Types”.
[jg1]Test_View_window_ Overcurrent
