Hv Test Plan Gis 400 Kv

Energy On-site AC Testing

Project: “Ashuganj North”

On-site AC High Voltage Test with UHF PD Detection Ashuganj North GIS at “400KV Substation” Description of Test Procedure and general Remarks

ETHP GS • Syed Atharul Islam

29.09.16, page 1 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Technical data Type: Rated voltage: Rated power frequency withstand voltage: Rated lightning impulse withstand voltage: Rated frequency:

GIS 420 kV 650 kV 1425 kV 50 Hz

AC high voltage test procedure The 400 kV GIS at Ashuganj North, Bangladesh substation will be tested on-site with ACvoltage according to IEC62271-203 at nominal gas pressure. The test is performed per individual phase. The test voltage is applied between one phase and earth. The test voltage will be supplied by a frequency tuned resonant test system. The HV test of each phase will be completed by detection of partial discharge (PD) activity at a voltage level of 1.2 times the rated voltage divided by root of 3. For PD detection the UHF method will be used. Measurements shall be done with the internal mounted PD sensors and PD instrument manufactured by DMS. After high voltage test the test section have to be earthed.

Test parameters · Conditioning: · · · ·

High voltage test: UHF PD detection: HV-test set: UHF PD detection:

290 kV for approx. 15 min 420 kV for 3 min 515 kV for 1 min (IEC 62271-203) 290 kV (1.2 x 245 kV/√3) WRV 3.6/680 with internal mounted PD sensors

Figure 1: Test cycle

ETHP GS • Syed Atharul Islam

29.09.16, page 2 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Technical specification HV-test set Power supply Rated power rated voltage rated current rated inductivity (3 stages) resonance frequency range

3~NPE 50Hz 400V 86 kVA 680 kV 3.6 A 525 H 50…300Hz

Test requirements · Secondary circuit of current transformers have to be short circuit and earthed · Secondary circuit of voltage transformers have to be open · Overhead lines, transformers, HV-cables and surge arrestors have to be disconnected, shielded and earthed · Safety distance of about 8 -10 meters to life parts UHF PD detection procedure and criteria to pass the test

ETHP GS • Syed Atharul Islam

29.09.16, page 3 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

The equipment have to withstand the test voltage for 1 min and should be free of significant PD activity for 1 min at PD detection level to pass the test. At U = 290 kV the PD amplitude should be less than “equivalent to 5 pC” according Cigré sensitivity verification for UHF PD detection and no typical PD charts should occur. The Siemens experience with UHF PD detection has to be taken into consideration. The PD detection by “UHF portable Monitor” is done for each PD sensor separately. After a time interval of more than 1 min without significant PD activity the following PD sensors are tested. A PD defect can be located by switching operation or travelling time measurement. If a PD defect has been removed from the test section, the PD detection will be repeated. Therefore the test voltage should gradual increased up to 515 kV for 1 min and afterwards decreased again to PD detection level of 290 kV. PD occurence during conditioning and high voltage test (1 min test) is possible and not a criteria to pass the test. The GIS has to withstand the 1min power frequency voltage of 515 KV. If during the testing breakdown occurs then the test should be repeated. If repeatedly breakdown occurs then we have to localize the fault and rectify it. If necessary perform switching operation of disconnector, circuit breaker to find breakdown point and to localize and verify.Once the fault is rectified, once again the three steps of voltage rise need to be followed, Now if the GIS withstands all three steps then it is said to have passed HV test. Subsequent to a repair the high voltage test is to repeat for the effected part of GIS.

ETHP GS • Syed Atharul Islam

29.09.16, page 4 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Test sequence The following pages are showing the sequence of test. This is to be considered as a general proposal. A detailed sequence of the test, adapted to the specific requirements of the substation will be arranged by the commissioning engineer in charge. All country/regional typical work instructions, safety rules and laws have to be followed! As rough rule of thumb, the time of cooling of the equipment can be calculated in the following way. (1)

Cooling time (min) = Testing time (min) multiplied by 10

In case of a standard HV-test of approx. 30 minutes, a cooling time of approximately 5 hours is to be expected, to reach the initial level.

Test Sequence 1- C07+C08+BUS1+BUS2+Bus 1 VT +Bus 2 VT

ETHP GS • Syed Atharul Islam

29.09.16, page 5 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Test Sequence 2- C09+C08+C04+BUS1+Bus 1 VT + C04 VT+ C09 VT

ETHP GS • Syed Atharul Islam

29.09.16, page 6 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Note- The sequence can be changed by HV test engineer during the HV as per site conditions.

Test Sequence 3 - C08+C06+C10+BUS2+BUSVT-2+ C06 VT+ C10 VT

ETHP GS • Syed Atharul Islam

29.09.16, page 7 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Note- The sequence can be changed by HV test engineer during the HV as per site conditions.

ETHP GS • Syed Atharul Islam

29.09.16, page 8 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Test Sequence 4 - C08+C05+C11+BUS-1+BUS VT-1+C05 VT+ C11 VT

ETHP GS • Syed Atharul Islam

29.09.16, page 9 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Test Sequence 5 - C08+C12+BUS1+ BUS VT1+ C12 VT

ETHP GS • Syed Atharul Islam

29.09.16, page 10 of 12

Energy On-site AC Testing

Project: “Ashuganj North”

Test Sequence 6 - C08 +BUS1 +BUS-2 + ALL Q2

Note- The sequence can be changed by HV test engineer during the HV as per site conditions.

ETHP GS • Syed Atharul Islam

29.09.16, page 11 of 12

Energy On-site AC Testing

ETHP GS • Syed Atharul Islam

Project: “Ashuganj North”

29.09.16, page 12 of 12