1 00:00:19,005 --> 00:00:20,007 Ratio Tab 2 00:00:20,032 --> 00:00:27,265 In this tab, CVT turn ratio test is performed where the voltage is given to the CVT primary and measured from the secondary. 3 00:00:27,290 --> 00:00:35,578 By dividing the primary and secondary values, turn ratio is obtained and the obtained value can be compared with the nominal value on the plate. 4 00:00:35,603 --> 00:00:44,085 For medium and high-voltage CVTs it is possible to perform this test by applying a low voltage or approximately 400 volts to the primary. 5 00:00:44,110 --> 00:00:52,406 If there are multiple measuring and protection secondary, it is necessary to measure voltages of all secondaries and obtain all their turn ratios. 6 00:00:52,431 --> 00:00:59,562 According to the IEC 60044-2 standard, the allowed error percentage is set in accordance with the accuracy class of the CVT. 7 00:00:59,587 --> 00:01:05,906 The first column of this accuracy class table and the turn ratio error percentage accuracy column are also available. 8 00:01:05,931 --> 00:01:13,499 In the following table, the mentioned error percentages are for cases where the voltage is higher than 2 percent of the nominal voltage. 9 00:01:13,524 --> 00:01:19,757 In accordance with the table related to protection CVTs, for example, if the accuracy class is 3P, 10 00:01:19,782 --> 00:01:28,335 its allowed error percentage in 2 percent of the nominal voltage is 6 percent and in 100 percent of the nominal voltage is 3 percent. 11 00:01:28,360 --> 00:01:32,960 To perform this test, first, fields of “State Settings“ section are introduced. 12 00:01:32,985 --> 00:01:38,803 In “V test“, “V actual“, “State Time“ and “Analog Input“ fields, the amount of test voltage, 13 00:01:38,882 --> 00:01:47,139 the actual applied voltage, the duration of the test and the input intended for transformer secondary voltage measurement are specified, respectively. 14 00:01:47,164 --> 00:01:54,366 It should be mentioned that inputs number 1 to 8 and input10 are used for voltage measurement. 15 00:01:54,391 --> 00:02:00,756 In noisy environments, there is some voltage on the inputs of the device and to increase accuracy, 16 00:02:00,781 --> 00:02:03,654 by selecting “At calibration state“ option, 17 00:02:03,679 --> 00:02:12,795 at the beginning of the test,another state with zero as its value is created and in the end, this measured voltage will be reduced from the final result. 18 00:02:12,820 --> 00:02:19,170 In “Turns Ratio Result”, the results of turn ratio test of every core are displayed after performing the test. 19 00:02:19,195 --> 00:02:27,849 In “V calc” field, the secondary voltage is calculated by the software in accordance with the values entered in “Test Object” and in “V test” field. 20 00:02:27,874 --> 00:02:34,256 In “V meas”, “Ratio Nom.” and “Ratio Act.”, the voltage measured by the input, 21 00:02:34,288 --> 00:02:40,106 the nominal turn ratio and the actual turn ratio are calculated by the software, respectively. 22 00:02:40,131 --> 00:02:47,333 The insertion position of the cores is specified in “Insert Mode” in a way that by selecting “All Core”, 23 00:02:47,358 --> 00:02:52,896 all cores are added to the “Result” table based on the selection between “Up” or “Down”. 24 00:02:52,921 --> 00:02:59,294 Also, by selecting “Specific core”, a specific core is added to the table in accordance with the choice of the user. 25 00:02:59,319 --> 00:03:06,302 In “Phase” section, in “Phase Nom” field, the amount of applied voltage to the CVT and in “Phase Act” 26 00:03:06,327 --> 00:03:11,872 the phase difference between the two sides of the transformer are displayed. 27 00:03:12,576 --> 00:03:19,730 Finally, the results of the evaluation are determined in accordance with the type of the core which can be protection, 28 00:03:19,755 --> 00:03:25,707 measurement or protection/measurement and also in accordance with what the user selects in “Assessment”. 29 00:03:25,739 --> 00:03:32,910 The insertion position of the cores in the table is specified by selecting the options available in “Insert Position”. 30 00:03:32,935 --> 00:03:36,707 Tables can be added by pressing “Insert Rows” button. 31 00:03:36,732 --> 00:03:39,605 Performing the test and analyzing the results 32 00:03:39,630 --> 00:03:47,730 To perform the test, as an example, 100 volts and 300 milliseconds are entered as the test voltage and State time, respectively. 33 00:03:47,755 --> 00:03:53,144 The CVT type is …. and only Core1 is going to be tested as an example. 34 00:03:53,169 --> 00:03:56,652 After pressing “Insert Rows”, since there are 3 cores, 35 00:03:56,677 --> 00:04:19,401 9 rows are inserted which in accordance with the test voltage and the CVT turn ratio, the nominal turn ratio value and Vcalc are …… and ….. respectively. 36 00:04:19,434 --> 00:04:29,790 To perform the test, the voltage of group A is connected to the CVT primary and the Input1 is connected to the CVT secondary to measure the voltage. 37 00:04:51,286 --> 00:04:57,376 To view the primary and secondary voltages during the test, Signal view is used. 38 00:04:57,401 --> 00:05:03,313 In the end, the intended row is selected and after right-clicking on it, Apply Test is selected. 39 00:05:03,338 --> 00:05:13,321 After the test, it can be seen that the test results are recorded in the table and since the angle fault and the turn ratio are within the range allowed in the standard, 40 00:05:13,346 --> 00:05:18,875 the test is passed. Other cores and phases are tested following the same procedure. 41 00:05:18,900 --> 00:05:24,781 After the test is finished, to add the results to the report “Add to Report” option can be used. 42 00:05:24,806 --> 00:05:35,438 Also, by using the cog next to this option, you can remove the items that do not wish to be added to the report before selecting “Add to Report” option. 43 00:05:35,463 --> 00:05:43,484 If, for any reason, wish to modify the wiring of the device, first they need to apply the test once and then check 44 00:05:43,509 --> 00:05:50,163 “Don’t Change Hardware Setting” option and select a different output from “Hardware Configuration” window 45 00:05:50,188 --> 00:05:56,944 and then set the Output Target at “VL1-E” and run the test after changing the wiring. 46 00:05:56,969 --> 00:06:05,873 To select other inputs, it should be noted that the selected Binary Input Target must be in accordance with the default “Binary Input Target”. 47 00:06:05,898 --> 00:06:12,973 For this, it is suggested to right-click on “Input1” row and “Cut” the information and “Paste” it in the intended row. 48 00:06:12,998 --> 00:06:20,958 Since it is possible that some users have also performed a “Megger” test for this equipment and they wish to have its results in a report, 49 00:06:20,983 --> 00:06:27,701 in “Megger Test Report” tab, they can select their intended row and column and by pressing “Insert”, 50 00:06:27,726 --> 00:06:36,458 created their required table and after inserting the test results and selecting “Add to Report”, add the information to the output report. 51 00:06:36,483 --> 00:06:42,279 Other options such as “Delete Report” are used to delete information of this page from the report. 52 00:06:42,304 --> 00:06:51,052 Also, “Export” and “Import” options are used to export the information of this page as an output file and import it if necessary. 53 00:06:51,077 --> 00:07:01,380 If the user wishes to set the characteristics of the created row and column as default for this section of the room, they can use “Set as Default” option.