The measured substation is located in Dhekeleia area in Larnaca. The measurements were performed on the 26th of November 2008 at 09:30 am. The EAC Dhekeleia Power Station comprises of two main areas. The first is the outdoor area comprising of the outdoor power substation and transformers and the distribution lines which includes the incoming and outgoing power lines. The second area is the working area building with the control rooms of the power station and the power generators. Measurements were performed within and outside the power station area.
Limiting exposure values have been provided by the ICNIRP recommendations and are guidelines to many countries and organisations. 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) |
|
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) |
|
50 Hz |
5000 |
80 |
100 |
Table 1: ICNIRP exposure limits for Occupational and General public exposure
The power as measured from the six transformers of total capacity 60 MW, at the time when the measurements were performed is listed below:
| Time | T1 (MW) | T2 (MW) | T3 (MW) | T4 (MW) | T5 (MW) | T6 (MW) |
| 9:30 | 41.2 | 0 | 49.1 | 45.9 | 50.5 | 60 |
| Utilisation | 68% | 0% | 82% | 77% | 84% | 100% |
Table 2: Maximum power consumption during EMF measurements Â
The maximum obtained values inside and outside the Power Station are represented below and compared to the ICNIRP specified limits of Occupational standards. For the first case, inside the Power Station, the highest magnetic field was observed in the cable room (point E), with a value 374 μT and a percentage of 74.80% as compared to the ICNIRP Occupational standard.
| Dhekeleia Power Station: Magnetic Fields Inside Power Station | ||
| Measurement Point | Maximum Magnetic Field / µT at Z Height /m -Percentage of ICNIRP Occupational Standard /% | |
| Magnetic Field Value / µT | ICNIRP % | |
| Electric Control Room | ||
| Measurement Point A | 9.52 | 1.90% |
| Measurement Point B | 0.99 | 0.20% |
| Measurement Point C | 0.33 | 0.07% |
| Measurement Point D | 3.26 | 0.65% |
| Shift Office Engineer Room | ||
| Measurement Point A | 0.33 | 0.07% |
| Measurement Point B | 0.15 | 0.03% |
| Measurement Point C | 1.6 | 0.32% |
| Power Generator 6 | ||
| Measurement Point A Busbars | 2.08 | 0.42% |
| Measurement Point A | 2.6 | 0.52% |
| Measurement Point B | 10.2 | 2.04% |
| Measurement Point C | 0.41 | 0.08% |
| Measurement Point D | 0.66 | 0.13% |
| Measurement Point E | 0.91 | 0.18% |
| Measurement Point F (1m away from generator) |
1 | 0.20% |
| Measurement Point G | 6.1 | 1.22% |
| Measurement Point H | 8.51 | 1.70% |
| Measurement Point I | 29.42 | 5.88% |
| Busbars | ||
| Measurement Point 415V Busbars T6 |
71 | 14.20% |
| Measurement Point 415V Â Busbars T1 |
11.52 | 2.30% |
| Unit Control Room | ||
| Measurement Point A | 0.21 | 0.04% |
| Measurement Point B | 0.18 | 0.04% |
| Cable Room | ||
| Measurement Point A | 11.65 | 2.33% |
| Measurement Point B | 1.12 | 0.22% |
| Measurement Point C | 3.12 | 0.62% |
| Measurement Point D | 19 | 3.80% |
| Measurement Point E | 374 | 74.80% |
| Measurement Point F | 3.76 | 0.75% |
| Measurement Point G | 0.46 | 0.09% |
| Busstacks T3, T6 and 11kV T1 | ||
| Measurement Point A (busstack T3) | 6 | 1.20% |
| Measurement Point BÂ (panel busstack T3) | 44.8 | 8.96% |
| Measurement Point CÂ (busstack 6 panel) | 6.88 | 0.00% |
| Measurement Point DÂ (busstack 6 behind panel) | 152 | 1.38% |
| Measurement Point E (busstack 6 clock) | 13 | 0.00% |
| Measurement Point F (11 kV VT busbar T1) | 23.68 | 30.40% |
| Measurement Point GÂ (11 kV VT busbar T1 height 1.75m) | 6 | 0.00% |
| Fuel Pump 33 | ||
| Measurement Point A | 121.2 | 24.24% |
| Measurement Point B | 10 | 2.00% |
| Measurement Point C | 0.6 | 0.12% |
| Evaporator Panel area | ||
| Measurement Point A (busbars) | 4 | 0.80% |
| Measurement Point B (busbars) | 24 | 4.80% |
| Measurement Point C (room) | 0.82 | 0.16% |
Table 3: Maximum Magnetic Field Measurements inside Substation
Accordingly the highest magnetic field value outside the power station was observed in the 66 -132 kV transformer area, with value 250 µT and a percentage of 50% as compared to the ICNIRP Occupational standard. This value was measured on the 66 kV cable side of the 66 -132 kV transformer.
| Dhekeleia Power Station: Magnetic Fields Outside Power Station | ||
| Measurement Point | Maximum Magnetic Field / µT at Z Height /m -Percentage of ICNIRP Occupational Standard /% | |
| Magnetic Field Value / µT | ICNIRP % | |
| Workshop | ||
| Machine A | 6.42 | 1.28% |
| Machine B | 0.13 | 0.03% |
| Electrical Welding | 20 | 4.00% |
| 11 -132 kV Transformer | ||
| Point A (cable tray) | 29 | 5.80% |
| Point B (height 1.75 m) | 50 | 10.00% |
| Point C (other cables) | 39.08 | 7.82% |
| Point D (11 kV side) | 110 | 22.00% |
| 132 kV Outside area | ||
| Point A (control board) | 7.46 | 1.49% |
| Point B (panel 1) | 4.33 | 0.87% |
| Point C (transmission lines height 1.75m) | 20 | 4.00% |
| Point D (panel 2) | 3.18 | 0.64% |
| 66 – 132 kV Transformer area | ||
| Point A (66kV side) | 250 | 50.00% |
| Desalinat6ion Panel area | ||
| Point A (Desalination panel) | 1.02 | 0.20% |
| Point B (Interbus T2) | 187 | 37.40% |
Table 4: Maximum Magnetic Field Measurements outside Substation