1 00:00:19,473 --> 00:00:22,875 Other Tests Performable in “Excitation Test” Tab 2 00:00:22,900 --> 00:00:28,414 By checking “Extra Data”, the additional information obtained from the excitation test is displayed. 3 00:00:28,439 --> 00:00:34,835 In the table of this section, the drawn current is displayed in EFS with 110 percent. 4 00:00:34,860 --> 00:00:40,625 Moreover, in “Custom” row it is possible to enter the voltage and view the current drawn in that voltage. 5 00:00:40,650 --> 00:00:46,828 For example, the current drawn in a 50 volt is 6.733m amps. 6 00:00:46,853 --> 00:00:48,117 “Ratio Table” 7 00:00:48,142 --> 00:00:54,773 In fact, this table is the standard turns ratio table which is completed by the software during the excitation test. 8 00:00:54,798 --> 00:01:00,210 Note that this table is completed using voltage turns ratio and in different burdens. 9 00:01:00,392 --> 00:01:05,015 Let us use a numerical example to explain how this section works. 10 00:01:05,040 --> 00:01:16,523 To begin the calculations, suppose that “Burden= 15 VA”, Current equals 0.5ln, power factor equals 0.8 and CT resistance equals 2 ohms. 11 00:01:16,548 --> 00:01:25,281 To create the nominal burden in CT nominal current, we can suppose that a 12 ohm resistance is connected to the two ends of the terminal. 12 00:01:25,622 --> 00:01:35,812 According to the equivalent circuit, in 0.5ln or 0.5 amp current, voltage of the parallel branch is achieved from 13 00:01:35,836 --> 00:01:46,732 According to the equivalent circuit, using the relation, voltage of the primary side is achieved as 7*1/500 =14mV. 14 00:01:46,757 --> 00:01:50,997 This number is the voltage which is (in half of the nominal current) to be measured in the primary. 15 00:01:51,021 --> 00:01:59,893 Therefore, to fill the .5ln and 15VA cells, the software needs to create the 7volt in the the parallel (secondary) 16 00:01:59,917 --> 00:02:06,472 branch and measure its equivalent in the primary and finally, compare the measured value with the applied value. 17 00:02:06,497 --> 00:02:16,784 To create a 7 volt in the parallel branch, the device and the software need to apply "Vterminal" voltage to the CT in accordance with the displayed relation. 18 00:02:16,809 --> 00:02:21,237 Since the current loaded from the device can be viewed at any moment, 19 00:02:21,262 --> 00:02:26,136 the voltage of the device to create the 7 volt parallel branch is obtained. 20 00:02:26,169 --> 00:02:37,995 The mentioned process is repeated for all cells of this table and the turns ratio error, phase displacement, composite error and “ALF” are calculated for different burdens. 21 00:02:38,020 --> 00:02:49,589 To perform this test, after doing the wiring for excitation test, it is necessary to connect the CT primary to inputs 1 and 10 and run the test after pressing “Init Test”. 22 00:03:57,877 --> 00:04:05,471 You will see that after the test is finished, the turns ratio obtained from “Ratio Table” is displayed in “N Turn”. 23 00:04:05,496 --> 00:04:07,962 Other than this “Pol.Check”, 24 00:04:07,987 --> 00:04:18,969 the tables related to this section are completed and the those cells that have error values beyond the allowed range are highlighted in red and displayed in “Error List” section. 25 00:04:18,994 --> 00:04:24,773 In the last table, “ALF” is calculated and displayed in different burdens. 26 00:04:24,798 --> 00:04:27,102 Resistance Measurement 27 00:04:27,127 --> 00:04:33,992 By checking “Rdc”, the winding resistance is measured using the voltage application and current measurement method. 28 00:04:34,017 --> 00:04:41,289 For this test, the capacitors are “Bypassed” using the binary output 1 and DC voltage is applied to the CT. 29 00:04:41,314 --> 00:04:48,907 Afterwards, input 5 is connected to the “CT” using binary output 3 and the actual voltage of the CT are measured. 30 00:04:48,932 --> 00:04:56,172 As you saw, during the process of resistance measurement, Binary outputs are closed. In the end, the resistance is measured.