PT. TRAFOINDO PRIMA PERKASA KNEE POINT TEST 1. Purpose This test is intended to obtain the knee point voltage of current transformer (CT). 2. Test equipment 2.1. Slide regulator, 5 A, 230 V. Use step up transformer to raise up output voltage. 2.2. Voltmeter 2.3. Amperemeter 2.4. Cable connection 2.5 mm2 3. Test circuit 1S1 A ~ Adjustable Voltage source V 1S2 Figure 1: Connection diagram of knee point test 4. Test procedure 4.1. Connect the circuit as shown as figure 1. 4.2. Primary winding and other(s) secondary winding is left opened. 4.3. Raise the voltage source step by step and record the voltage and current as table 1. CT Specification: Ratio : Serial no : Test core no : No. Voltage (V) Current (A) Remarks 1. 2. 3. 4. 5. 6. Table 1: Voltage and current of test 4.4. If current already reached to the nominal secondary current, the test is stopped. 4.5. For evaluation of test, send the record to: [email protected]/FAX: +6221-3850702 PT. TRAFOINDO PRIMA PERKASA PRIMARY CURRENT INJECTION TEST 1. Purpose This test is intended to verify that current transformation ratio as shown on the name plate is correct. Primary current injection test is not accuracy test, therefore the result of this test to calculate ratio error is not acceptable. 2. Test Circuit A ~ P1 1S1 Adjustable Current source A 1S2 P2 Note: Ensure to short-circuited secondary terminal prior to conduct primary current injection. Fail to do so will cause damage to current transformer. 3. Test procedure 3.1. Check the name plate ratio and primary current 3.2. Check the current source is able to raise up to nominal current of CT. 3.3. Check the size of primary cable 3.4. Check the terminal on secondary CT either core I, core II and or core III are shortcircuited. 3.5. Start to raise up the current and record with below simple table. CT Specification: Ratio : Serial no : Test core no : No. Actual primary current Actual secondary Actual ratio Calculated (A) current (A) ratio 1. 2. 3. 4. 5. 6.