Pole mounted transformer - Tseri
On the 7th of December 2006 at 18:00 pm electric and magnetic field measurements were performed for the Tseri 11KV - 415V pole mounted transformer. The pole mounted transformer of interest is located in Nicosia in the area of the old neighbourhood of Tseri.
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The transformer is rated at a nominal power of 200 KVA and at the time when the measurements were performed, the load current on the 415V side was recorded as
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Red Phase |
Yellow Phase |
Blue Phase |
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158A |
241A |
175A |
Table 1: Measured load current
By calculating the Average load current of all three phases as shown above we note that the load is 68% of the nominal load current (200KVA Transformer).
Limiting exposure values have been provided by the ICNIRP recommendations and are guidelines to many countries and organizations. The exposure limits at 50 Hz are tabulated in the following table according to the limits given by ICNIRP.
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Reference levels for Occupational exposure ICNIRP |
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Frequency |
Electric Field Strength, E (V/m) |
Magnetic Field Strength, H (A/m) |
Magnetic Flux Density, B (µT) |
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50 Hz |
10000 |
400 |
500 |
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Reference levels for General Public exposure ICNIRP |
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Frequency |
Electric Field Strength, E (V/m) |
Magnetic Field Strength, H (A/m) |
Magnetic Flux Density, B (µT) |
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50 Hz |
5000 |
80 |
100 |
Table 2: ICNIRP exposure limits for Occupational and General Public exposure
The mesh method has been employed to obtain the field distribution in the vicinity of the pole mounted transformer as shown below. The resolution of the measurements was 0,5m very near the transformer and 1m elsewhere.
The maximum electric field measured in the area at a point under the transformer and at a height of 1.75m was found to be 5.39 V/m and a percentage of 0.1% as compared to the ICNIRP General Public standard. The maximum obtained results for the RMS Magnetic fields in the area of the measurements are shown in table 3 and a comparison is made with the .ICNIRP recommendations.
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Pole Mounted Transformer Tseri: Magnetic Field Measurements |
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Distance from Field Line Starting Point /m |
Maximum Magnetic Field (µT) at Z Height (m) |
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0.3m |
ICNIRP % |
1 m |
ICNIRP % |
1.75 m |
ICNIRP % |
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Transformer Front Side Magnetic Field Measurements |
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0m of Building A Front Side |
0,68 |
0,68% |
0,51 |
0,51% |
1,29 |
1,29% |
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0.5m of Building A Front Side |
0,80 |
0,80% |
0,90 |
0,90% |
0,89 |
0,89% |
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1m of Building A Front Side |
1,32 |
1,32% |
1,39 |
1,39% |
1,48 |
1,48% |
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1.5m of Building A Front Side |
1,14 |
1,14% |
1,11 |
1,11% |
1,11 |
1,11% |
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2m of Building A Front Side |
0,59 |
0,59% |
0,49 |
0,49% |
0,51 |
0,51% |
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3m of Building A Front Side |
0,48 |
0,48% |
0,40 |
0,40% |
0,48 |
0,48% |
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4m of Building A Front Side |
0,46 |
0,46% |
0,39 |
0,39% |
0,53 |
0,53% |
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5m of Building A Front Side |
0,43 |
0,43% |
0,34 |
0,34% |
0,41 |
0,41% |
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Transformer Right Side Magnetic Field Measurements
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0m of Building A Right Side |
0,26 |
0,26% |
0,36 |
0,36% |
0,49 |
0,49% |
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1m of Building A Right Side |
0,19 |
0,19% |
0,22 |
0,22% |
0,23 |
0,23% |
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2m of Building A Right Side |
0,24 |
0,24% |
0,26 |
0,26% |
0,26 |
0,26% |
Table 3: Pole mounted transformer maximum field measurements
The magnetic field distribution at a height of 1.75m around the transformer is shown below. The highest field is around 0.8 - 1.2 µT which represents 0.8 - 1.3% of the recommended limit by ICNIRP
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Figure 3: Area of maximum measured Magnetic field |