High Voltage Overhead Power Lines

On the 23rd of October 2006 at 10:00am, electric and magnetic field measurements were performed for Dhekeleia-Athalassa overhead power lines 9 and 10. The transmission towers of interest are located in Nicosia in the area of Latsia.

The transmission towers are tall steel lattice structures that support overhead electricity conductors for power transmission. The overhead transmission lines in Latsia are rated at 132KV. The load at the time of measurement was 45A.

The configuration of the overhead transmission lines is represented in the following figure:

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.

Reference levels for Occupational exposure ICNIRP
Frequency	Electric Field Strength E (V/m)	Magnetic Field Strength H (A/m)	Magnetic Flux Density B (µT)
50 Hz	10000	400	500
Reference levels for General Public exposure ICNIRP
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 maximum obtained results for the RMS fields in the area of measurements are shown in table 2 and a comparison is made with the ICNIRP recommendations.

Dhekeleia-Athallassa Overhead Power lines 9-10: Tower Field Measurements
Distance from Field Line Starting Point (m)	Maximum Magnetic Field (µT) at Z Height (m) Percentage of ICNIRP General Public Standard (%)
Distance from Field Line Starting Point (m)	0.3m	ICNIRP % (100Î¼T)	1m	ICNIRP % (100Î¼T)	1.75m	ICNIRP % (100Î¼T)
Underground Cables Magnetic Horizontal Field
26m from Start Point (Along the Cables)	--	--	--	--	1.07	1.07%
4m Right of Start Point (Horizontal to the Cables)	--	--	--	--	2.17	2.17%
Maximum Electric Field (V/m) at Z Height (m) Percentage of ICNIRP General Public Standard (%)
1m Right of Start Point (Horizontal to the Cables)	--	--	--	--	2103	42.06%

Table 2: Maximum field measurements of overhead power lines area

The following plots show the magnetic field distribution in the measurement area at a height of 1.75m respectively. The first graph represents the magnetic field along the 30m field measurement line under the transmission line cables. Similarly the second graph represents the magnetic field along the horizontal field measurement line (15m left and 15m right from the centre point of the transmission line cables).

Figure 1: Measurements of Magnetic Field (µT) at 1.75m height

Figure 2: Measurements of Horizontal Magnetic Field (µT) at 1.75m height

Accordingly for the horizontal field measurement line (15m left and 15m right from the centre point of the transmission line cables) measurements of the Electric Field were also performed.

Figure 3: Measurements of Horizontal Electric Field (V/m) at 1.75m height

High Voltage Overhead Power Lines - Dhekeleia / Athalassa 9 and 10