Transformer Testing Procedure

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MEASUREMENT OF INSULATION RESISTANCE 

Configuration for a test

MEASUREMENT OF INSULATION RESISTANCE 

Procedure for testing

1. Test results evaluate the measurement configuration .

2. State the typical X – Y.

3. Connect X to the Megger’s +ve terminal.

4. Connect Y to the Megger’s -ve terminal.

5. Select the megger voltage rating

6. Start the megger & record the values at 60 seconds.

TEST FOR TURNS RATIO & MAGNETISING CURRENT

Configuration for a test (Turns Ratio)

TEST FOR TURNS RATIO
TEST FOR TURNS RATIO 1

Procedure for testing (Turns Ratio)

1. Separate primary, secondary, and neutral earth.

2. Turn on the kit.

3. Go to the transformer page.

4. Specify the test voltage & push the start button to see the test card.

5. A test voltage of up-to 400V is applied on the transformer high voltage (HV) side for this test.

6. This voltage is accurately measured inside.

7. The measuring input measures the voltage & phase angle on low voltage (LV) winding.

8. The ratio proportion is calculated automatically.

9. Repeat the test for each tap point.

Configuration for a test (Magnetising Current)

MAGNETISING CURRENT

Procedure for testing (Magnetising Current)

1. Keep the LV side open.

2. Apply 2000V to the HV side, as shown in the diagram, & evaluate the current reading.

3. Repeat the test at each tap point.    

WINDING RESISTANCE MEASUREMENT 

Configuration for a test (HV)

HV

Configuration for a test (LV)

LV

Procedure for testing

1. Separate primary, secondary, and neutral earth.

2. Turn on the kit

3. Go to the transformer page.

4. Following the manual’s directions, input the test current & click the start button and the test card displays

5. The measurement variance over time during the charging of the winding

6. After saving the measurement, the kit will automatically discharge the winding.

7. It measures the direct current voltage.

8. And determines resistance.

WINDING RESISTANCE

MEASUREMENT OF MAGNETIC BALANCE

Configuration for a test

MEASUREMENT OF MAGNETIC BALANCE

Procedure for testing

1. Separate primary, secondary, and neutral earth.

2. Use typical tap and apply a 1Ø voltage between R and Y.

3. Determine the voltages R and N, Y and N, B and N, Y and B, and B and R.

4. Repeat the procedure for all subsequent sequences in the transformer’s primary & secondary.

TESTING EQUIPMENT

CPC100

  • Current transformers,
  • Voltage transformers,
  • Groundingsystems,
  • Lines and cables, 
  • Circuit breakers

can all be tested with the CPC 100 test system. The test system is lightweight (approximately 29 kg), with a small design, and portable.

Insulation Tester

Megohmmeters are electrical meters used to check the insulation on wire & motor windings. They are also known as the insulation testers (or) commonly, meggers.

Multimeter

A volt/ohm meter, often known as a multimeter or multitester, is a type of electronic meter that can be used for several different kinds of measurements.

  • Voltage,
  • Current and
  • Resistance

are only few of the quantities that may be measured by a typical multimeter.

Leakage Meter

The most common tool for measuring leakage current is the leakage meter. They function similarly to clamp meters used to measure load currents but provide much better results when measuring currents under 5 mA.