Download Ground and Short Circuit

Obligations of the Company
The company has to take care that:
Equipment and switchgears are operated according relevant
standards
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The errection, extension and maintenance of the
switchgears and equipment are carried out by
• qualified technicians or
• under supervision of a qualified technician
Device
Gerät
Weaknesses are immediately eliminated
The switchgear or equipment will be sorted out in case of
dangererous condition.
ESTW/ Castor
Limit Distances of the Danger Area
Nominal Voltage
to 1000 V
up to 6 kV indoor
up to 6 kV outdoor
up to 10 kV indoor
up to 10 kV outdoor
up to 15 kV
up to 20 kV
up to 30 kV
up to 36 kV
up to 45 kV
up to 66 kV
up to 70 kV
up to 110 kV
up to 220 kV
up to 380 kV (Uimp = 950 kV)
up to 380 kV (Uimp = 1050 kV)
up to 480 kV
up to 700 kV
Distances
covering
90 mm
120 mm
120 mm
150 mm
160 mm
220 mm
320 mm
380 mm
480 mm
630 mm
750 mm
1100 mm
2100 mm
2900 mm
3400 mm
4100 mm
6400 mm
Working in the neighbourhood of a switchgear (ecxceptions
§ 8 BGV A3) is only allowed, if:
• The voltage free state is given and guaranteed for the
duration of the work
• Active parts are secured for the duration of the work
by covering or fences
• The minimum distances are kept.
Hochspannung
LEBENSGEFARHR !
§ 7 BGV A3
BGI 548
Coverage for nominal voltages upt to
1 000V
Coverage or fences for nominal voltages over 1 kV,
with additional air gap
ESTW/ Castor
Distance Limits
• The minimum distances should be
Following protection distances are valid for
activities of technician or instructed persons
or for supervised works
Following protection distances
are valid for civil works and
other non-electrical works at
the neighborhood of active
parts.
Mindestschutzabstand
Nennspannung
bis 1 000V
0,5 m
über 1 kV bis 30 kV
über 30 kV bis 110 kV
1,5 m
2,0 m
über 110 kV bis 220 kV
über 220 kV bis 380 kV
3,0 m
4,0 m
Nennspannung
Mindestschutzabstand
bis 1 000V
1,0 m
über
3,0 m
1 kV bis 110 kV
über 110 kV bis 220 kV
über 220 kV bis 380 kV
Tabelle 102:
DIN VDE 0105-100
Schutzabstände
Schutzabstand
4,0 m
5,0 m
Tabelle 103: DIN VDE 0105-100
Annährungszone, Schutzabstände
§ 7 BGV A3
BGI 548
ESTW/ Castor
5 safety Rules
ESTW/ Castor
Fünf-Sicherheits-Regeln International
ESTW/ Castor
Process of a Voltage Check
or
1. Check of the voltage testing device
2. Volting testing device at
refence voltage
Red light
3. Testing of the equipment at all poles
Green light
4. Volting testing device at refence
voltage
Red light
ESTW/ Castor
Ground and Short Circuit
The cable in trenches will be exclusively cut with agrounded hydraulic scissor.
No one is allowed to stay in the trench during that work !
Exception
 Zero voltage is given
 and the course in the trench can be indentified!
Short circuit in a trench
Grounding and short circuit is mandatory at the connection of cable and overhead line.
ESTW/ Castor
Grounding and Short Circuit
Additional rules for switchgears with nominal
voltages over 1 kV
For works on transformers, both sides are to be
grounded and short ciruit, even if the nominal
voltage on the LV side is under 1 kV. This rule is also
valid for three or multiple winding transformers.
Beside grounding and short-circuit at the working
location, at least one switching location must be
earthed and grounded for overhead lines with a
nominal voltage from 1 kV up to 30 kV. For higher
nominal voltages, all switching locations have to be
grounded and short circuit.
Grounding and short circuit at one of the next poles
is allowed in case of pole breakers.
For works on cables, isolated lines, electrical equipment, which is connected over
spur cables or isolated lines (i.e. motors) grounding and short-circuit is not
mandatory. But all switching locations must be grounded and short-circuit.
Grounding and short circuit is mandatory at the connection of cable and overhead line.
.
ESTW/ Castor
Working Release
The working location can be only released for
working by the responsible, if
 Condution allowance (VE) exists
 All measures according
DIN VDE 0105-100 have been carried out
 The responsible person of the switchgear
has released the working allowance to the
working responsible
 All persons, which are involved to the work,
are instructed by the working responsible.
 The working release must be clearly
formulated.
 Therefore a written form for the working
release is mandatory for most distribution
companies according the operation manual.
 (Contents: local conditions, grounding and
protection measures, working distances,
possible dangers)
ESTW/ Castor
Behaviour at the Working Location
Activities can only be started, if the working responsible (AVO) has released the
working location.
The working responsible defines the scedule of work and
coordinates the works of the workers in the plant.
Hochspannung
LEBENSGEFAHR !
Works should be only carried out, if a
order exists.
The necessary protection clothes have
to be used!
The working area should only be left via the
defined exit!
The 5 safety rules have to be kept under all conditions !
ESTW/ Castor
Energizing after Termination of the Works
Energizing must be carried out with the same accuracy as for the deenergizing before the works. Normally this will be done in the reverse order.
It is very important to check the working location for tools or materials, which
have been left, before removing the safety measures. Eventually,
commissioning tests have to be carried out.
Safety measures should be only removed, if all persons have left the danger
area.
Short circuit and grounding equipment should be removed at the working
location at first and than at the other locations.
First remove the short circuit and than
the grounding!
Then the siwitchgear has to be
assumed to be under voltage !
ESTW/ Castor
Energizing after Termination of the Work!
ESTW/ Castor
Change of Fuses
Dangers during change of fuses:
• Interruption under load
=> arcs
• Change of fuses
=> weak protection against direct touch
Loaded fuses should only be changed:
Fuse load breaker
• at circuits with low power
• by using load breakers at first if available
• for LV fuses with approbriate tools, handled by instructed
persons or technicians.
• Personal protection clothes (PSA) have to be used!
DIN VDE 0105 - 100
ESTW/ Castor
Personal Protection Equipment
Die Safety association BGFE recommends the exchange of thermoplaqstic
helments after 4 years and duroplastic helmets after 8 years
Protection hand cuff
Helment with face protection
NSpg.-LiBo
Heavy flammable clothes
Isolating suit
Safety shoed S2 or S3
ESTW/ Castor
Switching with Second Person
NO statement about no. Of persons in VDE 0105-100 and BGV A3
Exception: BGV A1 dangerous works (working under voltage)
exceptionally
– a dangerous
has danger
to be carried
out by due to the
„DangerousIf –works
are works
with a work
higher
potential
one person,
measures
to be taken:
process, the
kind ofapprobriate
work, the
used have
materials
or the environmental
conditions.
 other persons should be in visual distance
A higher degreeof
danger
can patrols
be caused by mechanical, electrical, chemical,
regular
control
biological, thermal
influencesystem
or radiation.“
 information
in regular time steps
All switching actions have to be carried out by two
persons in switchgears with no protection against
dangerous impacts of arc flash or electrical strike.
ESTW/ Castor