Folie 1

1
Working with Zero Voltage

Rule 3 Zero voltage check of a LV overhead line
2
Working with Zero Voltage
Rule 5 Covering or remove nearby live parts,
separation plates for MV switchgears
3
Working under Voltage
Working with distance, cleaning of a transformer
Working with insulation clothes, installation of
a 1 kV cable joint
Working at high potential,
installation of a MV overhead line
4
Working under Voltage
Installation of a cable joint
Installation of a T-joint
Examples for working with insulation clothes
5
Working under Voltage
Working on high potential
6
Conductor Links I
Check characteristics of material! Cu no
problem Al non-conducting oxid surface
Reaction on contact pressure (cold flowing)
high thermal expansion cleaning
required before starting of work Cu-
and Al-conductors can not be connected directly.
Cupal-junctions have to
be used!

• Thermal conductor junctions (for example welding)
• Mechanical conductor junctions
• Dont damage the cable structure !

7
Mechanical Connections
Wrong !
Correct !
Wrong !
Correctly clamped
Contact surfaces for AL-and CU
8
Conductor Links III
screw link

3. plug-in connector spring
contacts
9
Accessoires I

1. Tapped joint

10
Accessoires II

• Cold fluid joint
• 4. Cast resin joint

• Hot shrink joint

11
Accessoires III

• Cold shrink technique
• Elastic slip-on technique (for terminals)
• Moulded connectors

12
Cable Joints

• Requirements
• water resistent even under volatile ambient
  temperatures
• corrosion resistent
• The metal cover should be connected with the
  neutral, the metal screen or the metal sheath

1. Straigth joints
2. Transfer joints
3. Branch joints
4. Termination joints

3
4
1
2
13
Installation of a Joint
14
Termination
Hot shrink
Oil immersed cable

• - Installation without tension
• only with special clamps
• keep necessary lengths !

Oil immersed termination in SF6-switchgear
Termination of oil pressure cable 110 kV
15
Installation Faults

• Removing clamp fat from links and cable terminals
• Usage of wrong links and cable terminals
• Usage of wrong clamp accessoires
• Wrong clamping sequence

• XLPE cables
• Cutting the insulation
• Cutting the screen or the conductor wires
• Wrong usage of the abrasion tools

Tape in a joint tube

• Oil immersed cables
• Wrong bending radius (damage of sheath and
  conductor)
• Cutting of the Pb sheath
• Overheating of the sheath
• Damaging of the paper insulation

16
Cable Arrangement
trench
Ground
Surface
Depth higher than 1,25 m Add. Construction
required Entering and leaving via ladders!
Fill-in material
0,6 0,8 m
Cover plate / warning tape
bedding material
0,2 m
Trench profile
0,3 m
Plain ground of trench, No stones with sharp
edgesFill-in material to enter layerwise Using
machines for compression only until 30 cm
coverage Ducts should be completely bedded
17
Installation Rules for Cable Trenches
DIN 4124
Trenches are working places. The equipment and
safety must fullfill the same requirements as the
office of a director!
Making of trenches and laying of cables in
trenches are the most dangerous works of the
complete construction works!
18
Horizontal Construction
min5 cm
min8 cm
min5 cm
plate
top plate
19
Construction Rules
Exclude dangerous ambient impacts Keep the
minimum ambient laying temperature (XLPE
cable 5C oil immersed
cable 5C) - Keep dust and humidity away

• Transport
• Attention during rolling of coils (only short
  distances, be aware of the right direction!)
  cable terminations should be kept try during
  transport and installation
• fixation of the cable terminations

Cable drum
20
Cables on Drums
21
Installation Rules

• - avoid mechanical stress
• take care of min. bending radius
• take care of max. forces (documentation of the
  draw forces!)
• avoid un-necessary bending of cable

cable winch
pivotted cable roller
Ziehmaschine
Correct bending radii multiple core cable 20 x
D One core cable 10 ... 15 x D
Documentation
22
Cable Installation
Rolling Direction
Draw Direction
23
Kabelverlegung
Take Care During Rolling Down!
24
Installation Rules
Draw force transfer only over cable sheath
Cable grip
Cable grip at a110-kV-gas pressure-cable
Pulling eye For bigger forces
Wire sheath 9 One sheath cable 3 Three sheath
cable 1
XPLE cable without metal sheath and without
armour
Transfer of force via sheath and core
25
Installation Rules

• Existing Cables and Joints
• Dont move existing cables
• Use shells for lifting
• Lift joints without draw forces
• Dont step on cables or joints to stand on or
  to leave the trench

26
Overhead Lines, Pole Types
F
F
0,8 m
Wood screw 16 mm x 100 mm
Wire clamp
lock
Insulation
At least . 1/5 l
Protection of termination
mind. 3,5 m
gt 0,7 m
1,2 m
1/6 l At least. 1,6 m
Pole wood
Termination made of concrete
27
Overhead Lines, Pole Types
Double pole 2 single poles, fixed connected
increase of the draw forces
A-Pole
Wooden poles, which are older than 2 years, have
to be secured against falling, if forces at the
pole top have been changed.
Pole foot
28
Overhead Lines Distances LV
everywhere
Roof angle 15
Tree beside the line
1,25 m
Tree not climbable
2,5 m
5 m
For windows, tops, etc.
street
Tree not climbable
For buildings and streets (concitions for courses
and distances in DIN VDE 0210)
29
Overheadlines, Insulators
180
In public networks insulator N 95
insulator N 95/2
insulator S 115
300
180
300
300
500
Connection of conductor wires
500
Al linking wire
Leiterseil
30
Overhead Lines Surge Arresters
Location at branches at end of spur lines at
intermediate cables or terminations
Max. Distance 1000 m in areas with high
lightning activity 500 m
Surge arrester
TN-network at phase conductors
TT-network at phase conductorsIT-network
at neutral conductor
Grounding at lowest distance with low grounding
impedance
ISO-Disconnector
31
Surge Arresters
- Temporary overvoltage (Load shedding,
earth fault) duration 0,1 sec 2 h
level up to 17 kV (Ur12 kV) up to 34 kV (Ur22
kV)
- Switching overvoltages in normal circuits
frequency lt 1 Hz level up to 30
kV (Ur12 kV) up to 60 kV (Ur22 kV)
energizing of de-energizing of lines fast
peaks 0,1 10 µs level up to 22 kV (Ur12
kV) up to 44 kV (Ur22 kV) in inductive
circuits fast peaks 0,1 10 µs
level up to 40 kV (Ur12 kV) up to 80 kV (Ur22
kV)
- lightnings fast peaks 0,1 10 µs
level up to 190 kV
32
Insulated Overhead Lines
No special distances required!
Branching
NFA2X 4x70 rm 0,6/1 kV
Surge arrester
ISO-Disconnector