干式变压器英文试验大纲.docx

1、干式变压器英文试验大纲Testing Items、Methods 、Procedure and Formulas：No.Testing ItemsTesting Methods Procedure and Formulas1Voltage ratiomeasurement andcheck of vectorgroupAdjust the tap changer, and measuring voltage ratio error of each tap of HV-LV. The test result of error at the nominal tap should be 0.4%.

2、The vector group should be Dyn11.The formula is as following: K=U1/U2 No.Testing ItemsTesting Methods Procedure and Formulas2Winding D.C.resistance measurementTo measure D.C. resistance of HV and LV windings at winding end by HS305, The test result of error: phase 4%，line1000M ； LV:50M)Connection di

3、agram of insulation resistance measurement is as following:No.Testing ItemsTesting Methods Procedure and Formulas4No.A.C. voltagewithstand testTesting ItemsApplied voltage withstand test uses 50Hz sine-wave single-phase A.C. voltage, tested winding of transformer is shorted and energized, the other

4、non-tested windings are shorted grounding, also the core, clamp and tank are grounded. This test is considered to be qualified, if there is no discharge, breakdown and no sudden decrease of testing voltage. The testing voltages are:HV & neutral-38kV 60s, LV-3kV 60s.(13.8KV/0.4KV)HV & neutral-50kV 60

5、s, LV-3kV 60s.(22KV/0.4KV)Testing Methods Procedure and Formulas5Induce withstand voltage1、induce withstand voltageThe wiring diagram of induce withstand voltage test is as following:L.V ac surge magnetism,HV side is open-circuit.Wiring diagram is following:H.V induce withstand voltage:（13.8 kV2 ；22

6、kV2）Use 50kVA、200Hz generator set three-phase output to L.V winding of tested transformer. H.V tap position is at 3 step, Test lasts for 30s （Formula: test time=120*50/200=30s）. This test is considered to be qualified if there is no following situation- current-increasing, difficulty to apply voltag

7、e, discharge and breakdown and other abnormal situation. t=120*fr/f t: test time fr: rated frequency f: test frequency No.Testing ItemsTesting Methods Procedure and Formulas6Measurement of no-load loss andno-load currentThe tested transformer is energized at LV side by 200kVA three phase booster.App

8、ly the 400V voltage from L.V side to surge magnestim, Measure the I 0 and P 0 . After correction, I0 % and P0 should meet the requirements of technical specification (13.8kV/0.4kV:1.15kW;22kV/0.4kV: 1.35kW). During the test, HV side is open-circuit, neutral point is earthed. Po= Po（1+d） Po: no-load

9、loss after revised. Po: measured no-load loss d=（U ave value -U virtual value ）/ U ave valueNo.Testing ItemsTesting Methods Procedure and Formulas7Measurement of short-circuit impedance and on-load lossAccording to requirements of the standard, the load loss and impedance at rated step, should be me

10、asured. The measurement should be conducted between HV and LV windings with HV energized and LV short-circuit. At rated step, the measurement value should be according to the technical requirement (13.8kV/0.4kV:5.3kW;22kV/0.4kV: 5.41kW).The power supply for this test is from200kVA generator unit and

11、 transmits to tested transformer input terminaP115=（Pk-Pr）/K+Pr*K P115 : load loss at 115 Pk: measured load loss Pr: resistance loss K: temperature coefficientP115 : load loss at 115Pk: measured load lossPr: resistance lossK: temperature coefficientNo.Testing ItemsTesting Methods Procedure and Formu

12、las8No.Measurement of partial dischargeTesting ItemsApplied voltage phase to phase is 1.8Ur(Ur is rated voltage),and duration of voltage application is 30s. Then reducing the voltage phase to phase to 1.3Ur at holding the supply,lasts 3 min;In the course ,measuring partial discharge.The test circuit

13、 for three phase thransformer partial discharge test. 1 - LV winding 2 - HV winding 3 - Measurement intrument S - Switch.The method of appling voltage is 9 diagram.9 Diagram the method of appling voltage for the partial discharge.Testing Methods Procedure and Formulas9Measurement of sound levelDurin

14、g test, HV tap changer should be at rated step, Applying rated voltage and rated frequency at LV side. The sound pressure level should be measured at specified line which is 1m from reference radiating surface. Distance between two adjacent measuring points should be less than 1m. Before and after s

15、ound level test, background sound level also should be measured. At last to correct and calculate the measured data according to standards, the result should meet the customers requirement: 47dB. No.Testing ItemsTesting Methods Procedure and Formulas10No.Lightning impulse test Testing Items The nega

16、tive full-wave lightning impulse tests of HV, LV terminal are as following: Full-wave: 1.230%/5020%s, HV(peak): 95kV (13.8KV/0.4KV) LV(peak): 125kV (22KV/0.4KV) Test procedure is as following: Negative full-wave impulse at first reduced 50% voltage; Negative full-wave impulse at third rated voltage.

17、 During test, theres no abnormal sound and the wave shape will not be abnormal, This test is considered to be qualified. Testing Methods Procedure and Formulas11Measurement of temperature rise Temperature test (type test) 1. Technical test requirement:Temperature rise of winding :100K Test supply: 2

18、00KVA,50Hz three phase booberThe windings temperature-rise were calculated by the formula c = c 1+(e/c)1.250.8 using the result obtained by two separate temperature-rise;the first test with onlu no-load loss,the second test with only load loss.First test The high-voltage winding of the transformer w

19、as op-circuited and the low-voltage winding was supplied at the rated voltage(400V);these supply were applied until the steady-state condition was reached.Then,resistance of windings were measured in direct current(see graphics)in order to determine their temperature-rise by resistance variation met

20、hod.Second test The low-voltage winding of the transformer was short-circuited and the high-voltage winding was supplied at a tast voltage to allow the rated current (13.8kV/0.4kV:26.36A;22kV/0.4kV:16.53A) to pass through the high-voltage winding;these supply was applied until the steady-state condition was reached.Then,resistances of windings were measured in direct current in order to determine their temperature-rise c by resistance variation method.