-Fixed support locks and dedicated locks shall be used for fixing conductors.

-Support crossing poles are permitted to be used in the case that they are adjacent to dead end poles.

4.Requirement for conductor and lightning conductor

When overhead power lines with voltage exceeding1kV cross rivers, etc., conductors andlightning conductors shall have cross-sectional area or mechanical strength not lessthan that of the following conductors and lightning conductors.

-Aluminum conductor with cross-sectional area of 70mm2.

-Aluminum conductor steel reinforced or aluminum alloy conductor steel reinforced with crosssectional area of 35mm2.

Conductors with cross-sectional area less than 240mm2 are prohibited to be connected within the span but conductors with cross-sectional area not less than240mm2 are permitted to be connected at only one point in the span.

Article 276. Crossing Areas with Water

Safe distance from the overhead power lines to the means of waterway transport implementationshall be secured not less than the distance in this article in Technical RegulationVol.1.

Article 277. Arrangement of Signs and Signals for Areas with Water

The signs and signals, which are installed at banks at the both sides of rivers and channels where ships and boats sail, shall comply with related State regulations,

Chapter 3-3-11 Crossing or Going Nearby Overhead Power Lines

Article 278. Requirement when Crossing and Going Nearby Other lines

1. Pole location

When overhead power lines cross other overhead power lines, the cross angle betweenthe lines is not stipulated.

Overhead power lines with higher voltage shall be arranged above overhead power lines with lower voltage. As an exceptional case, overhead power lines with voltage 110kVupto which have conductors with cross-sectional area exceeding 120mm2 and double insulators arepermitted to be arranged above overhead power lines with voltage of 220kV.

2. Pole type

Anchor poles and support poles are permitted to be used at intersection where overhead power lines cross other overhead power lines.

3. Conductor and insulator

Cross-sectional area of conductors of overheadpower lines with voltage exceeding1kV at intersection shall not be less than the value shown in article 271 in Technical RegulationVol.1 and this Guideline.

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Conductors of overhead power lines with cross-sectional area less than240mm2 at higher height are prohibited to be connected in intersected span but conductors with crossectional area not less than 240mm2 are permitted to be connected at only one point in the span.

When overhead power lines at higher height shall use support poles, the conductors shall be fixed by fixed support locks. Ifcross-sectional areas of conductors are not less than 300mm2, slide locks are permitted to be used.

When post-type insulators are used atoverhead power lines with voltage exceeding1kV at higher height, the insulators shall be double installed in intersected spans.

Article 279. Vertical Distance in Crossing Places

1. Vertical distance between conductors or between the nearest conductor and the lightning conductor

In the calculation for vertical distance betweenconductors or between the nearest conductor and the lightning conductor, air temperature shall be 20°C. (Refer to Table 279 of Technical Regulation)

Poles of overhead power lines with voltage upto 110kV at lower height are permitted to be installed under conductors of other overhead power lines, if vertical distance between the lowestconductor of the line at higher height and the top of poles of the lines at lower height is not thanless the value shown in Table 279 in Technical RegulationVol.1 plus 2m..

2. Requirement for overhead power lines with voltage up to 1kV

When overhead power lines with voltage up to1kV and with voltage exceeding 1kV are arranged on

distance and horizontal distance between two lines shall not be lessthan the values in Table279 in this Guideline.

Article 280. Horizontal Distance between Outer Edge Conductors

The horizontal distance between theouter edge conductors of overhead power lines withvoltage exceeding 1kV shall comply with the value of horizontal distance shown in Table8-1 in article 8 in Technical RegulationVol.1.

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Article 282. Requirement for Overhead Power Lines with Voltage of 500kV

The impact of overhead power lines with voltage of500kV on communication and signal lines shall be considered with the contents in article 298 in Technical Regulation and this Guideline.

Article 283. Other Requirements for Poles

Protection against collision by vehicles shall be installed incompliance of the contents in article 118 in Technical RegulationVol.1 and this Guideline.

Article 284. Intersection with Underground Telecommunication’s Cable

Article 285. Installation on Same Poles

When overhead power lines with voltage up to 110kV and peripheral telecommunication’s cables are arranged on same poles, they shall comply with safety requirements and be agreedwith management agency of overhead power lines.

Article 286. Going Nearby Communication and/or Signal Structures

Overhead power lines with voltage exceeding1kV arranged nearby underground communication and signal lines shall comply with the requirements in article281 in Technical RegulationVol.1 and this Guideline.

Article 287. Protection against Electromagnetic Induction

1. Limitation of induced voltage

The voltage of communication and signal lines induced from overhead power lines shallnot exceed 650V, which is calculated by Carson pollaczek formula as below.

V=ϖ M KI

V:Induction voltage

ϖ: ϖ =2π (f: Frequency (Hz))

K: Shielding coefficient I: Fault current (A)

M: Mutual inductance between overhead power line and communication and signal lines per a kilometer (H/km). The calculation of mutual inductance is as shown below.

(1) kd < 0.5

(3) kd ≤ 10

M = - j 4 ×10- 4 (H/km)

(kd)2

Overhead power line

d

Communication and signal line

hp

S

hc

Figure 287 Distance for induction

d: Distance between overhead power line and communication and signal line (m)

d= S 2 + (hp − hc)2

S: Horizontal span between overhead power line and communication and signal line (m) hp, hc: Height of overhead power line and communication and signal line (m)

k:k = 4πϖ ×10−7

σ: Electric conductivity (1/ Ω m)

ker’(kd), kei’(kd): Modified Bessel function (refer to the following table)

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Article 288. Prevention of Corona Noise and Radio, Television Wave Reception Interference

1. Corona noise

(1) Permissible value of corona noise

Signal to noise ratio due to corona noise shall comply with the following levels.

-Fair or cloudy weather: 40dB and more

-Rainy weather: 20dB and more

SN=S-N

SN: Signal to noise ratio (dB)

S: The measured value of broadcast electric field intensity during fair weather (dB)

N:Corona noise level is calculated by the next item (2) (dB)

(2)Corona noise level

N=Ns+3.5(E-15)+Nd+(Kh+Nx)

N: Calculated corona noise level (dB)

Ns: Corona noise level on electrical gradient of surface of conductorith wthe diameter of 30mm. Normally, it is adopted to 43dB. (dB)

Nd: Correction to conductor diameter is calculated by the following formula. Nd= 40log10 23r (dB)

r: Radius of conductor (cm)

Kh: Attenuation of corona noise against the height of conductor is calculated by the following formula.

h:Vertical distance between the lowest conductor and measured point on ground surface (m) Nx: Attenuation of corona noise against perpendicular direction to overhead power line

x: Horizontal distance from conductor to measured point

E: The maximum electrical gradient of surface of conductor (kV/cm)

The maximum electrical gradient of surface ofsingle conductor is calculated by the following calculation.

E= 18CV (kV/cm) r

V:Voltage of overhead power line (kV) C: Electrostatic capacity to ground

C= 0.02413 ( µ F/km) log 2h

10 r

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