Center Break Isolator and double Break Isolator 
These disconnectors are , no load switching devices
which physically isolate the lines. They are designed for
horizontal outdoor application and can also be designed
for vertical installation. For earthing and closing of
switchyard portions of the installation, the earthing
switches are provided on disconnector. If required.
The following documents were referred to during the preparation of this specification. In case of conflict, the provisions of this specification shall take precedence.
IEC 129:1975: Alternating Current Disconnectors (Isolators) and Earthing Switches
IEC 60694:2002: Common Specifications for High Voltage Switchgear and Controlgear
BS 729: Hot dip galvanized coating on iron and steel articles
IEC62271-102
Isolator (Disconnector) - a mechanical switching device which provides, in the open position, an isolating distance in accordance with Electrical Safety requirements.
SERVICE CONDITIONS
The isolator shall be suitable for continuous operation outdoors in tropical areas at altitudes of up to 2200m above sea level, humidities of up to 90%, average ambient temperature of +30ºC with a minimum of -1ºC and a maximum of +40ºC and heavy saline conditions along the coast.
4.2. DESIGN AND CONSTRUCTION
4.2.1 The Isolator, Solid Link shall be designed and constructed in accordance with IEC 129 and IEC 60694.
4.2.2 The isolating link shall be of the vertical opening, designed for single phase manual operation. It shall be easily removed and replaced by using a portable operating rod.
4.2.3 The isolating link shall incorporate double porcelain insulators to suit voltage requirements and mounted on hot dipped galvanised steel under base suitable for vertical mounting.
4.2.4 The isolating link shall be arranged so that each unit is mounted independently on an angle bracket. It shall be supplied complete with the angle bracket and accessories suitable for mounting on 'U' type steel channel. The drawings to be submitted shall indicate all the applicable mounting positions.
4.2.5 The isolator shall be designed such that in fully open position, it shall provide adequate electrical isolation between the contacts on each phase. It shall conform to the requirement as single point isolation for safety.
4.2.6 All steel parts shall be hot dip galvanized to BS 729. The minimum coating of galvanizing required is 80 microns.
4.2.7 The solid link shall be removable from the mounting by use of operating rod.
4.2.8 All current carrying parts of the isolator shall be made of high conductivity material.
4.2.9 The isolator shall be fitted with clamp connectors for Aluminium (ACSR) conductor of Aluminium (ACSR)conductor of up to 18.2mm diameter.
The rating of the complete isolator shall be as follows: -
Rated voltage
36 kV
Rated frequency
50 Hz
Rated lightning impulse withstand voltage
200 kV
Rated power frequency withstand voltage, dry
95 kV
Rated normal current
400 Amps
Rated short time withstand current for 3 sec, min.
18.0 kA
Minimum creepage distance of insulators
900 mm
S OLID LINKS 11KV | N/O | DETAIL | | DATA |
| 1 | Description | | Solid link assembly complete with link
rated at 200A and mounting bracket to PIESA 002. (See Figure 1 to Figure 12 below) |
| 2 | System conditions of service
a) nominal Voltage (Un) r.m.s |
kV |
11 |
| b) maximum system voltage (Um) r.m.s | KV | 12 |
| c) earthing | | Effective & non effective |
| d) Frequency | Hz | 50 |
| 3 | Site conditions of service
a) altitude |
m |
1400 |
| b) Operating Ambient temperature | °C | -1 to 40 |
| c) Humidity | % | 85 |
| 4 | Rating | | |
| a) Nominal voltage | kV | 11 |
| b) Rated current | Solid link |
A |
200 |
Cut out base |
A |
200 |
| 5 | Electrical components | | |
| a) Insulator material specification | | Porcelain |
| Dielectric strength | | |
| Lightning impulse withstand (1.2/50) | kV | 95 |
Power frequency wet withstand voltage
r.m.s | kV | 28 |
| 6 | Specific creepage distance | mm/kV | 25 |
| 7 | General information to be provided
with bid:
Drawings and brochures showing outline and general arrangement |
Yes/No |
Yes |
| | b) Detailed drawings of all items
showing critical tolerances to be provided with bid | Yes/No | Yes |
| 8 | Previous Type test report/certificate on
complete solid link assembly to be provided with bid |
Yes/No |
Yes |
| 10 | Routine tests (acceptance tests on
sample
Product) to be provided on delivery | Yes/No | Yes |
| 11 | Applicable standard | | PIESA 002 |
| 12 | Other applicable standards | | NRS 035
SABS IEC 60282-2
SABS IEC 60186
BS 137 part 2 |
T RI-LINKS Lot 3-(a) 11kV with interrupters | N/O | DETAIL | | DATA |
| 1 | TYPE | | 11kV pre-assembled gang
operated overhead line load break switch complete with expulsion interrupters |
| 2 | Mounting configuration | | Horizontal |
| 3 | Mode of operation | | Manually operated pole
mounted linking rod and handle with locking facilities |
| | a) nominal Voltage (Un) r.m.s | kV | 11 |
| b) maximum voltage (Um) r.m.s | KV | 12 |
| c) earthing | | Effective & non effective |
| d) Frequency | Hz | 50 |
| e) rated current | Amp | 400 |
| f) Fault closing capacity | kA | 12.5 |
| 4 | Site conditions of service
a) altitude |
metres |
1400 |
| b) Operating Ambient temperature |
°C |
-1 to +40 |
| c) Relative humidity | % | 85 |
| 5 | Electrical components | | |
| a) Insulator material specification | | High Temperature Vulcanised
Silicon rubber |
| b) Cross arm and operating controls materials | | Hot dip galvanized steel to
SAN760 |
| Dielectric strength | | |
| Lightning impulse withstand (1.2/50) | kV | 95 |
| | Power frequency wet withstand voltage r.m.s | KV | 28 |
| | Short time current rating -1sec | kA | 12.5 |
| 6 | creepage distance | mm/kV | 25 |
| 7 | General information to be provided with bid:
Drawings and brochures showing
Outline and general arrangement |
Yes/No |
Yes |
| 8 | Previous Type test report/certificate on complete
assembly to be provided with bid | Yes/No | Yes. |
| 9 | Routine tests (acceptance tests on sample
Product) to be provided on delivery. | Yes/No | Yes |
| 10 | Applicable standards | | IEC62271 |
FURTHER REQUIREMENTS:
W ater sh all not be able to accumu l ate on a ny p art of the equip m ent nor sh all a ny f eatu re in trodu ce mo isture in to a ny compo n ent.
The d esign sh all inco rpo r ate all re ason able p r e c aut ions and p rovis ions for the s af e ty of p ersonn el co n cer n ed with the oper at ion and main t en an ce of the s a m e.
The cur r ent path sh all be su ch that load cur r ent sh all on ly flow through high condu ct ive mat eri als su ch as copp er and i ts al l o ys. Lo ad cur rent shall not be p ermit t ed to flow through f er rous components, spr ings, or sp rin g -load ed m e ch anis ms.
All lo ad cur rent p aths sh all be so d esigned th at t he r ele v ant pa rts of the s wi t ch are c ap able of car r ying the s p ecifi ed r a t ed cur r ent wi thout ex c eeding the p ermit t ed temp er ature ri s e.
S UPPLIMENTARY NOTES
Suppl i ers should give suf fic i ent info rmation in cl uding dr awings ( which must be b rie f, cl e ar and to the poin t) on how th eir switch d esigns add r esses th ese r equir ements. Furth er, Supplie rs m ay o ff er b et t er al t ern at iv es that are of cost be n e fi ts to customer, It is therefore imperative that schedule "B" is completed by the tenderer. Any deviations/modifications/alternatives specification must be listed in schedule "C.
33 kV with interrupters | N/O | DETAIL | | DATA |
| 1 | TYPE | | 33kV pre-assembled gang
operated overhead line load break switch complete with expulsion interrupters |
| 2 | Mounting configuration | | Horizontal |
| 3 | Mode of operation | | Manually operated pole
mounted linking rod and handle with locking facilities |
| | a) nominal Voltage (Un) r.m.s | kV | 33 |
| b) maximum voltage (Um) r.m.s | KV | 36 |
| c) earthing | | Effective & non effective |
| d) Frequency | Hz | 50 |
| e) rated current | Amp | 200 |
| f) Fault closing capacity | kA | 12.5 |
| 4 | Site conditions of service
a) altitude |
metres |
1400 |
| b) Operating Ambient temperature |
°C |
-1 to +40 |
| c) Relative humidity | % | 85 |
| 5 | Electrical components | | |
| a) Insulator material specification | | High Temperature Vulcanised
Silicon rubber |
| b) Cross arm and operating controls materials | | Hot dip galvanized steel to
SAN760 |
| Dielectric strength | | |
| Lightning impulse withstand (1.2/50) | kV | 170 |
| Power frequency wet withstand voltage r.m.s | KV | 70 |
| | Short time current rating -1sec | kA | 12.5 |
| 6 | creepage distance | mm/kV | 25 |
| 7 | General information to be provided with bid: | | |
| | Drawings and brochures showing
Outline and general arrangement |
Yes/No |
Yes |
| 8 | Previous Type test report/certificate on complete
assembly to be provided with bid | Yes/No | Yes |
| 9 | Routine tests (acceptance tests on sample
Product) to be provided on delivery | Yes/No | Yes |
| 10 | Applicable standards | | IEC62271 |
FURTHER REQUIREMENTS:
W ater sh all not be able to accumu l ate on a ny p art of the equip m ent nor sh all a ny f eatu re in trodu ce mo isture in to a ny compo n ent.
The d esign sh all inco rpo r ate all re ason able p r e c aut ions and p rovis ions for the s af e ty of p ersonn el co n cer n ed with the op er at ion and main t en an ce of the s a m e.
The cur r ent path sh all be su ch that load cur r ent sh all on ly flow through high condu ct ive mat eri als su ch as copp er and i ts al l o ys. Lo ad cur rent shall not be p ermit t ed to flow through f er rous components, spr ings, or sp rin g -load ed m e ch anis ms.
All lo ad cur rent p aths sh all be so d esigned th at t he r ele v ant pa rts of the s wi t ch are c ap able of car r ying the s p ecifi ed r a t ed cur r ent wi thout ex c eeding the p ermit t ed temp er ature ri s e.
S UPPLIMENTARY NOTES
Suppl i ers shou ld give su ffi cient info rmation in cl uding dr awings ( which must be b rie f, cl e ar and to the poin t) on how th eir switch d esigns add r esses th ese r equir ements. Furth er, Supplie rs m ay o ff er b et t er al t ern at iv es that are of cost be n e fi ts to custoemr.
11 kV without interrupters | N/O | DETAIL | | DATA |
| 1 | TYPE | | 11kV pre-assembled gang
operated overhead line switch without expulsion interrupters (non-load break switch) |
| 2 | Mounting configuration | | Horizontal |
| 3 | Mode of operation | | Manually operated pole
mounted linking rod and handle with locking facilities |
| | a) nominal Voltage (Un) r.m.s | kV | 11 |
| b) maximum voltage (Um) r.m.s | KV | 12 |
| c) earthing | | Effective & non effective |
| d) Frequency | Hz | 50 |
| e) rated current | Amp | 400 |
| 4 | Site conditions of service
a) altitude |
metres |
1400 |
| b) Operating Ambient temperature |
°C |
-1 to +40 |
| c) Relative humidity | % | 85 |
| 5 | Electrical components | | |
| a) Insulator material specification | | High Temperature Vulcanised
Silicon rubber |
| b) Cross arm and operating controls materials | | Hot dip galvanized steel to
SAN760 |
| Dielectric strength | | |
| Lightning impulse withstand (1.2/50) | kV | 95 |
| Power frequency wet withstand voltage r.m.s | KV | 28 |
| | Short time current rating -1sec | kA | 12.5 |
| 6 | creepage distance | mm/kV | 25 |
| 7 | General information to be provided with bid: | | |
| | Drawing and brochures showing
Outline and general arrangement |
Yes/No |
Yes |
| 8 | Previous Type test report/certificate on complete
assembly to be provided with bid | Yes/No | Yes |
| 9 | Routine tests (acceptance tests on sample
Product) to be provided on delivery | Yes/No | Yes |
| 10 | Applicable standards | | IEC62271 |
FURTHER REQUIREMENTS:
W ater sh all not be able to accumu l ate on a ny p art of the equip m ent nor sh all a ny f eatu re in trodu ce mo isture in to a ny compo n ent.
The d esign sh all inco rpo r ate all re ason able p r e c aut ions and p rovis ions for the s af e ty of p ersonn el co n cer n ed with the op er at ion and main t en an ce of the s a m e.
The cur r ent path sh all be su ch that load cur r ent sh all on ly flow through high condu ct ive mat eri als su ch as copp er and i ts al l o ys. Lo ad cur rent shall not be p ermit t ed to flow through f er rous components, spr ings, or sp rin g -load ed m e ch anis ms.
All lo ad cur rent p aths sh all be so d esigned th at t he r ele v ant pa rts of the s wi t ch are c ap able of car r ying the s p ecifi ed r a t ed cur r ent wi thout ex c eeding the p ermit t ed temp er ature ri s e.
S UPPLIMENTARY NOTES
Suppl i ers should give suf fici ent info rmation in cl uding dr awings ( which must be b rie f, cl e ar and to the poin t) on how th eir switch d esigns add r esses th ese r equir ements. Furth er, Supplie rs m ay o ff er b et t er al t ern at iv es that are of cost b e n e fi ts to
33 kV without interrupters | N/O | DETAIL | | DATA |
| 1 | TYPE | | 33kV pre-assembled gang
operated overhead line switch without expulsion interrupters (non-load break switch) |
| 2 | Mounting configuration | | Horizontal |
| 3 | Mode of operation | | Manually operated pole
mounted linking rod and handle with locking facilities |
| | a) nominal Voltage (Un) r.m.s | kV | 33 |
| b) maximum voltage (Um) r.m.s | KV | 36 |
| c) earthing | | Effective & non effective |
| d) Frequency | Hz | 50 |
| e) rated current | Amp | 200 |
| 4 | Site conditions of service
a) altitude |
metres |
1400 |
| b) Operating Ambient temperature |
°C |
-1 to +40 |
| c) Relative humidity | % | 85 |
| 5 | Electrical components | | |
| a) Insulator material specification | | High Temperature Vulcanised
Silicon rubber |
| b) Cross arm and operating controls materials | | Hot dip galvanized steel to
SAN760 |
| Dielectric strength | | |
| Lightning impulse withstand (1.2/50) | kV | 170 |
| Power frequency wet withstand voltage r.m.s | KV | 70 |
| | Short time current rating -1sec | kA | 12.5 |
| 6 | creepage distance | mm/kV | 25 |
| 7 | General information to be provided with bid: | | |
| | Drawing and brochures showing
Outline and general arrangement |
Yes/No |
Yes |
| 8 | Previous Type test report/certificate on complete
assembly to be provided with bid | Yes/No | Yes |
| 9 | Routine tests (acceptance tests on sample
Product) to be provided on delivery | Yes/No | Yes |
| 10 | Applicable standards | | IEC62271 |
FURTHER REQUIREMENTS:
W ater sh
all not be
able
to
accumu
l ate on
a ny p
art of the
equip
m ent nor sh
all
a ny
f eatu
re in
trodu
ce mo
isture in
to
a ny
compo
n ent.
The d
esign
sh
all inco
rpo
r ate
all re
ason
able p
r e c aut
ions
and p
rovis
ions for the s
af
e ty of p
ersonn
el co
n cer
n ed with
the op
er
at
ion
and main
t en
an
ce of the s
a m e.
The
cur
r ent path sh
all be su
ch that load
cur
r ent sh
all on
ly flow through high
condu
ct
ive mat
eri
als
su
ch
as
copp
er
and i
ts
al
l o ys.
Lo
ad
cur
rent shall not be p
ermit
t ed to flow through f
er
rous
components, spr
ings, or sp
rin
g -load
ed m
e ch
anis
ms.
All
lo
ad
cur
rent
p aths
sh
all be so d
esigned th
at
t he r
ele
v ant pa
rts of the s
wi
t ch
are
c ap
able
of
car
r ying
the s
p ecifi
ed r
a t ed
cur
r ent wi
thout ex
c eeding
the p
ermit
t ed temp
er
ature ri
s e.
S UPPLIMENTARY NOTES Suppl
i ers should give su
ffi
cient info
rmation
in
cl
uding dr
awings (
which
must be b
rie
f,
cl
e ar
and to
the poin
t) on
how th
eir switch d
esigns
add
r esses th
ese
r equir
ements.
Furth
er, Supplie
rs m
ay o
ff
er
b et
t er
al
t ern
at
iv
es that
are
of
cost be
n e fi
ts to.
