0.3 Telecommunications Clearances Clearances from Conductors PDF

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Summary

236 February 2011 10.3 Telecommunications Clearances Clearances from Conductors Low Voltage Low Voltage 11kV, 22kV, 12. 7kV (insulated, 132kV (uninsulated) SWER, 33kV, 66kV including services) m m m m Attached to pole 0. 8 0. 3 2. 0 2. 0 Unattached to 3. 0 3. 0 3. 0 4. 0 pole (2. 1) (2. 1) (2. 1) (3...

Description

236

10.3

February 2011

Telecommunications Clearances

Clearances from Conductors Low Voltage (uninsulated) Attached to pole Unattached to pole

m 0. 8 3. 0 (2. 1)

Earthed Metalwork LV Assets5 LV switching devices Street light brackets, stay wires

Low Voltage (insulated, including services) m 0. 3 3. 0 (2. 1)

11kV, 22kV, 12. 7kV SWER, 33kV, 66kV

132kV

m 2. 0 3. 0 (2. 1)

m 2. 0 4. 0 (3. 0)

Clearances from attached Assets (other than conductors) Low Voltage Low Voltage (uninsulated) (insulated) m m 0. 45 0. 75 0. 4 1. 0 0. 5 0. 1 -

Notes: 1.

The clearances shown in brackets are minimum clearances as listed in the Regulations, Codes and Agreements.

2.

Telecommunication cables include broadband cable (cable TV), ADSS, telephone and pilot cables.

3.

The clearances indicated in the table represent the separation between cables/conductors and not king bolt spacings.

4.

Telecommunication cables are not normally attached to poles where the highest voltage exceeds 66kV.

5.

‘LV assets’ include attachments and cabling related to street lights, overhead services, LV underground cable terminations and LV bridging.

6.

The minimum clearance above telephone lines shall be determined with the power line super-circuit at maximum design temperature and the telecommunication sub-circuit at 15°C.

NS220

237

10.4

February 2011

Railway Crossings Dimension

Application

LV Insulated or Bare

11kV, 22kV, 12. 7kV SWER, 33kV, 66kV

132kV

m

m

m

A

Over electrified railway lines

12. 0 (11. 6)

12. 0 (11. 6)

12. 0 (11. 6)

B

Over nonelectrified railway lines

8. 0 (7. 6)

10. 0 (8. 8)

12. 0 (10. 7)

Electrified Railway Crossings

Non-Electrified Railway Crossings

A

B

Notes: 1.

The figures in brackets in the table are minimum clearances as listed in the Regulations, Codes or Agreements.

2.

Railway crossings shall be designed in association with the Railways Infrastructure Corporation requirements.

NS220

238

10.5

February 2011

Transmission Undercrossings The Designer shall consult with TransGrid or other asset owner, submitting a detailed plan of the line route in the vicinity of the crossing, showing positions of distribution and transmission structures, as well as a distribution line profile with conductors at 5ºC.

Upper Circuit 132kV Lower Circuit

Ausgrid Circuits and Cables - All voltages

>132 – 275kV

>275 – 330kV

>330 – 500kV

m

m

m

m

No wind

2. 4

2. 8

3. 8

5. 2

wind

1. 5

2. 8

2. 6

3. 6

Notes: 1.

The table provides minimum requirements to prevent circuit to circuit flashover, under both normal and fault conditions, between aerial conductors or cables of different circuits that cross each other and are not attached to the same pole or support at the point of crossing.

2.

Wind condition is where the lower circuit is subject to blowout and swings upward.

3.

The clearances listed in the table may need to be increased due to local factors or to meet safe approach distances required for construction, operation and maintenance.

4.

Minimum clearance of distribution conductors from Transgrid structures is 15m.

5.

A sketch of Transmission undercrossings shall be submitted to Transgrid for approval. The sketch shall show plan and profile views of the proposed undercrossing and include details of poles, conductor heights and other relevant data.

6.

If conditions are such that it is likely that the lower circuit can flick up into the higher circuit e. g. due to vegetation, the vertical separation (C) at the crossing point shall be: C = 2D where: C = Required intercircuit clearance with upper circuit at max. design temp. D = Conductor sag of the lower circuit at 15°C

7.

Install terminations on undercrossing circuit either side of transmission line easement to permit easier undercrossing conductor temporary removal to permit Transmission Line reconductoring works.

8.

Do not position Distribution or Subtransmission line support structures under Transgrid conductor span.

9.

Consider HV Induction Hazard reduction in line design construction & maintenance.

NS220

239

10.6

February 2011

Navigable Waterway Crossings Clearances

Required Clearance R = W + V + E + S Electrical Clearances for Uninsulated Conductors, E

Required Waterway Crossing Data Clearance Element

Data Source

Circuit Voltage (kV)

Clearance (mm)

HAT + wave effects

NSW Maritime/ Dept of Lands

” 33

300

Height of expected vessels

NSW Maritime/ Dept of Lands

66kV – 132kV

800

Electrical clearances

Ausgrid

As per Electrical Clearance table

220

1300

Safety margin

Ausgrid

Based on risk assessment – min. 2200mm required

275

2000

330

2600

400

3000

500

3600

Considerations

Notes: 1.

The ‘Crossing Controller’ is responsible for determining the final clearance. The Crossing Controller can be an Ausgrid person.

2.

Waterway crossings over navigable waters are determined in association with the relevant statutory bodies or landowners, e. g. NSW Maritime or Department of Lands and other interested entities. The following may be required for overhead crossings:

x Warning signs, signage lighting on both sides of the waterway x Coloured marker balls and/or coverings attached to conductors. x Waterway crossing signs are to be designed in accordance with TI 2000 Overhead Mains Crossings of Other Services. 3.

Any excavation or filling activities undertaken in association with the crossing must be approved by the responsible landowner.

4.

The approval process is incorporated into the Crossings of NSW Navigable Waters: Electricity Industry Code.

NS220

240

10.7

February 2011

Streetlight Clearances Low Voltage Dimensi on

Location

A

Vertically: above street light

B

Horizontally: from any part of the street light

66kV – 132kV

11kV – 33kV

Insulated

Bare neutral

Bare Active

Insulated with earthed screen

Insulated without earthed screen

Bare or covered

Bare

m

m

m

m

m

m

m

0. 1

2. 7

2. 7

2. 7

2. 7

3. 7

4. 5

0. 1

0. 3

0. 6

0. 1

0. 6

1. 5

2. 5

NS220

241

10.8

February 2011

Vegetation Clearance Refer to NS179 Vegetation Safety Clearances. Distribution and Transmission Lines Clearance at Pole to nearest Conductor Conductor Type and Voltage

Clearance along middle 2/3 of span to nearest conductor in rest position

Urban

Bushfire Risk Area

Urban

Bushfire Risk & Urban Spans > 100m

m

m

m

m

0. 5

0. 5

0. 5

1. 0

0. 5

0. 5

1. 0

1. 5

1. 0

1. 5

Horizontal – 1. 5 Vertical above – 1. 5 Vertical below – 1. 0

2. 5

11kV, 22kV bare

1. 5

2. 0

2. 5

3. 5

11kV, 22kV covered

1. 0

1. 0

2. 0

2. 5

33kV covered

1. 5

2. 0

2. 5

3. 5

>22kV – 66kV bare conductor

2. 0

2. 0

3. 0

4. 0

>66kV to 132kV bare conductor

3. 0

3. 0

4. 0

5. 0

x x x

LVABC insulated service cables pilot cables

HVABC LV - bare

Around poles and structures

2. 0

Around stay wires

2. 0

NS220

242

February 2011

Notes: 1.

Add 1.5m for spans between 200m and 400m and 2.0m for spans greater than 400m.

2.

For vertical clearances, add 2.0m for spans between 200m and 400m, and 3m for spans greater than 400m. For horizontal clearances on spans greater than 200m, trim to 10m from the outer conductor, or to the limit of the easement where the easement width exceeds 10m from the outer conductor.

NS220

243

10.9

Engineering Notes Under development

NS220

February 2011...