SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS
OF TRANSMISSION LINES
Description of Inspection
and Maintenance Work
1. Visual inspection (A walk
around visual inspection
from ground level and
keeping in view the safe
limits of approach to live
and moving parts to check
apparent
condition,
abnormal noise, rust on
body of the equipment and
component parts, etc.)
2. Foot Patrolling Inspection
(Mechanical Defects such as
missing/loose
braces,
Condition
of
Jumper
Terminal Pad, Missing Split
Pins, and Other Problem
Areas such as Cultivated
and Jungle Growth, Effects
of Polluted Areas/Deserts,)
3. Climbing Inspection
(General
Problems,
Evaluation of Condition of
Line). Dead Line or Live
Line
4. Conductor Condition
(Loose Strands, Broken
Strands, Dislocated Spacers,
Vibration Dampers, etc.)
5.
Overhead
Shield
Wire/Earthing
Conductor
(Loose Strands, Broken
Strands,
Dead
end/suspension
clamps,
OPGW
Splicing
Box
Condition, etc.)
6. Structure Marking (Faded
and
Obsolete
Signs:
Numbering, Danger Plates,
Phase Marking, etc.)
7.
Insulator
Testing
(Insulator
String)
(Mandatory Before Live
Specified Time Period
D/W M3/6
Y1 Y5/10
Yes -
Remarks/Criteria/Standard/Safety
Precautions
Wear PPE and carry basic line man
tools, earth resistance test set,
binocular, etc. Make entries of the
observations in check sheets/note
book.
-
Yes
-
-
Should be OK and no defects (foot
patrolling should be done twice a
year on all lines)
-
-
Yes
-
Should be OK and no defect
(Climbing inspection should be done
once a year on all towers)
Should be OK, intact and secured
Should be OK, intact and secured
-
Yes
-
-
Should be OK intact as per design
(Replace or repair as required)
-
Yes
-
-
Should be OK and intact (Replace
failed insulator)
1
Line Work)
8. Insulator Washing and Greasing (before Foggy
Season
Yes
-
-
Should be OK and no defects
(insulator washing should be done
twice a year on all lines in polluted
areas)
Should be OK and no hotspot/s
(thermovision survey should be done
twice a year on all lines)
Should be OK and no defect
(Vibration studies should be done
twice a year on all lines)
9. Thermovision Survey
-
-
Yes
-
10. Vibration Studies
-
-
-
Yes
Yes
-
-
-
Should be OK and intact and
secured
Yes
-
-
-
Should be OK and intact and
secured
-
Yes
-
-
Should be OK and intact and
secured
-
Yes
-
-
-
-
Yes
-
Should be OK and intact and
secured
Should be OK and no damage
-
-
Yes
-
Should be OK and no damage and
no missing hardware
Yes
-
-
-
-
-
-
Yes
-
-
-
Yes
Should be OK and intact, no damage
and no missing hardware
Should be OK and intact, no
damage, and no missing hardware
Should be OK and intact
Yes
-
-
-
Should be OK and intact
TOWER
11. Footings Soil: Eroded,
Back filling, De-watering of
saline/rainy area, etc.
12. Footings Concrete:
Chipped, Cracked, Broken,
etc.
13.
Base
Structure:
Loose/Missing Braces and
Missing Nut/Bolts, etc.
14. Counter Poise
15.
Steel
Braces/Joint
Plates:
Bent,
Rusted,
Broken, etc.
16.
Tower
Members:
Twisted, Broken, Rusted,
Pitted
17. Step Pins/Bolts: Loose,
Missing, Rusted, etc.
18. Bolts: Loose, Missing,
Rusted
19.
Galvanizing/Paint:
Peeled, Pitted, etc.
20. Danger Plates/ Phase
Plates/Signs:
Worn,
Damaged, Missing, etc.
2
8. TRANSMISSION LINE TECHNICAL DIRECTIVE
Basic Maintenance Program of Transmission Lines
SCOPE
This directive provides for the basic minimum requirements to keep lines in an
acceptable and reliable condition. Maintenance is discussed under the following
headings:
1) Foot Patrol
2) Climbing Inspection/Maintenance
3) Structure marking
4) Insulator Testing
5) Insulator Washing & Greasing
6) Thermovision Survey
7) Vibration Studies
8) Commissioning
9) Condition Survey
1) FOOT PATROL
Foot Patrol should be done twice a year on all transmission lines.
This should identify most mechanical defects and point out problem areas that
require further attention.
A report from the field on Form LMS- 1 & LMS-2 (copy attached) is required by TSG
for evaluation.
2) CLIMBING INSPECTION/MAINTENANCE
2.1) This program is used to evaluate the condition of a line. A report from the
field on Form LMS-3 & 4 is required by TSG for evaluation. It should identify
general problems, if any, which would lead to a rehabilitation program if cost
justified.
2.2) A ten year cycle is required for all transmission lines. 10% of each line will be
inspected each year. If many serious defects are found on a line a more frequent
cycle for those lines should be discussed with TSG (N5P0015).
2.3) Climbing maintenance should be scheduled as follows:
Divide the line into several sections (each section may contain 10 towers) and
then arrange to inspect 10% of each section every year. This will then sample the
whole line every year.
2.4) Minor defects should be repaired during the inspection. Spare Material should
3
be available on the job. site for these repairs.
2.5) Climbing maintenance can be performed deadline or live line depending on
circuit availability.
3) STRUCTURE MARKING
Faded and obsolete marking signs shall be replaced / repainted as required.
4) INSULATOR TESTING
4.1) It is required to test insulators on a string prior to performing live line work
on or near an insulator string.*(N5P008 & N5P0013)
4.2) Testing insulators on 10 to 20% of a line will point out manufacturer defects as
well as electrical in service defects. This program should be considered if a variety of
insulator failures occur on a line.
5) INSULATOR WASHING/GREASING
In locations where there is a buildup of atmospheric pollutants, insulators shall
be washed or greased at a frequency such that flashovers are prevented.
The frequency will be determined by experience and/or testing of samples *(Old
No. TSG/TL-008)
6) THERMOVISION SURVEY
6.1) T his program identifies potential connection failures such as hot sleeves, pads
and bolted connections which may burn-down the conductors.
6.2) Thermovision can be done from the air or the ground. For transmission lines a
helicopter is highly desirable. At terminal towers or in built up areas a truck may
he required.
6.3) Normally, the thermovision is done at the time when there is maximum
load on line and each line is completed on a yearly cycle. (Thermovision check
Form LMS-6)
7) VIBRATION STUDIES
7.1) Vibration studies on transmission lines should be done using the following order
of preference.
a) Lines having broken strands at suspension clamps.
4
b) Lines with no dampers.
c) Lines that have wire dampers.
d) Lines that have one damper per span
e) Lines that have two dampers per span.
7.2) GS0 should identify the lines that should be studied and set up a program in
consultation with TSG.
8) COMMISSIONING
8.1) Commissioning of lines should start when construction forces begins to erect
structures on new lines. On rehabilitation work, start the commissioning when the
field work begins.
8.2) Commissioning is required to insure that the line is constructed to specifications
and to acceptable standards.
8.3) For lines 100km in length one man can usually do most of the work except for
tower bolt checking and verification.
8.4) Sag checks must be made separately from GSC, at the time of sagging the
conductors.
8.5) Check 20% of the towers and all dead-end towers for proper bolt torque.
20% of tower bolts on these towers should be verified for tightness, using a torque
wrench.
8.6) Suspension clamp, dampers and dead-end conductor hardware are to be
checked on the towers identified for commissioning.
9) CONDITION SURVEY
9.1) Condition survey is done on as and when as required basis.
9.2) Normally a survey is required to verify conductor to ground clearances as
well, as for allowable heights of proposed under builds such as distribution
facilities. This may also be used to determine maximum loading due to sags on the
transmission line.
5
9. REFERENCE DATA FOR COMPARISON WITH THE TEST RESULTS
Reference data and previous record is one of the important pre-requisite for an
effective operation and maintenance program. For evaluation of different test results
and to take decisions on the bases of these test results one must need some reference
values and the permissible limits. Such reference data may be the factory test results
or commissioning test results or the accepted test results of similar make/type/model
equipment or the recommendations of certain reputed standards/specification. In this
section, the most commonly applicable data has been compiled as a ready reference
for the user of this SOP. This data has been collected from all the possible sources,
however supply of new or more data along with feedback comments will be
welcomed.
6
Table-9a: CHARACTERISTICS OF UNUSED UNINHIBITED MINERAL
INSULATING OIL: IEC 296 (Old Specifications)
CHARACTERISTICS OF
UNUSED UNINHIBITED MINERAL
INSULATING OIL: IEC 296 (Old Specifications)
Sr. Property
Permissible
Values
for
Measured
No.
Characteristics
Class-I
Class-II
Class-III
1
Appearance
Clear,
free Clear,
free Clear,
free
from sediments from sediments from sediments
and suspended and suspended and suspended
matter
matter
matter
3
2
Density kg/dm at 20 ≤0.895
≤0.895
≤0.895
°C (old Specific
Gravity)
3
Interfacial
≥40
≥40
≥40
Tension/Surface
Tension at 25 °C
(mN/m) or (N/m x
10-3)
4a Kinematic Viscosity ≤ 16.5
≤ 11
≤ 3.5
2
mm /s at 40 °C
(Centistokes)
4b Kinematic Viscosity ≤ 40
≤ 25
≤6
2
mm /s at 20 °C
(Centistokes)
4c Kinematic Viscosity ≤ 800
2
mm /s at -15 °C
(Centistokes)
4d Kinematic Viscosity ≤ 1800
2
mm /s at -30 °C
(Centistokes)
4e Kinematic Viscosity ≤ 150
2
mm /s at -40 °C
(Centistokes)
5
Pour Point °C
≤ -30
≤ -45
≤ -60
6
Flash Point °C
≥ 140
≥ 130
≥ 95
7
Neutralization Value/ ≤ 0.03
≤ 0.03
≤ 0.03
Acidity (mg KOH/g)
7
8
9
3
11
12
13
14
Water Content mg/kg Max. 30ppm
(ppm)
(mg/kg)
for
bulk supply or
40ppm (mg/kg)
for delivery in
drums and IBC
Break Down DES(kV ≥
30
as
at 2.5 mm gap)
delivered and ≥
50
after
treatment
Tan δ / Dielectric ≤0.005
Dissipation FactorDDF (at 40 to 60 Hz
& 90 °C)
Oxidation Stability ≤0.40
Neutralization
* see note
Value(mg KOH/g)
Oxidation Stability
≤0.10
Sludge % by mass
* see note
Corrosive Sulfur
Non corrosive
Anti-oxidant
Not detectable
Additives
Max. 30ppm
(mg/kg)
for
bulk supply or
40ppm (mg/kg)
for delivery in
drums and IBC
≥
30
as
delivered and ≥
50
after
treatment
≤0.005
Max. 30ppm
(mg/kg)
for
bulk supply or
40ppm (mg/kg)
for delivery in
drums and IBC
≥
30 as
delivered and ≥
50
after
treatment
≤0.005
≤0.40
* see note
≤0.40
* see note
≤0.10
* see note
Non corrosive
Not detectable
≤0.10
* see note
Non corrosive
Not detectable
* Note. The determinations on the oxidized oil are limited to the neutralization
value and to the sludge however, in certain countries it is usual to determine also
the DDF. In this case the maximum value of DDF will be established by
agreement between purchaser and supplier.
8
Table-9b: CHARACTERISTICS OF UNUSED
INSULATING OIL: IEC 296 (Old Specifications)
INHIBITED
MINERAL
CHARACTERISTICS OF
UNUSED INHIBITED MINERAL
INSULATING OIL: IEC 296 (Old Specifications)
Sr. Property
Permissible Limiting Values for Measured
No.
Characteristics
Class-IA
Class-IIA
Class-IIIA
1
Appearance
Clear,
free Clear, free from Clear,
free
from sediments sediments and from sediments
and suspended suspended
and suspended
matter
matter
matter
3
2
Density kg/dm at ≤0.895
≤0.895
≤0.895
20 °C (old Specific
Gravity)
3
Interfacial
≥40
≥40
≥40
Tension/Surface
Tension at 25 °C
(mN/m) or (N/m x
10-3)
4a Kinematic Viscosity ≤ 16.5
≤ 11
≤ 3.5
2
mm /s at 40 °C
(Centistokes)
4b Kinematic Viscosity ≤ 40
≤ 25
≤6
2
mm /s at 20 °C
(Centistokes)
4c Kinematic Viscosity ≤ 800
2
mm /s at -15 °C
(Centistokes)
4d Kinematic Viscosity ≤ 1800
2
mm /s at -30 °C
(Centistokes)
4e Kinematic Viscosity ≤ 150
2
mm /s at -40 °C
(Centistokes)
5
Pour Point °C
≤ -30
≤ -45
≤ -60
6
Flash Point °C
≥ 140
≥ 130
≥ 95
9
7
8
9
10
11
12
13
Neutralization
≤ 0.03
Value/ Acidity (mg
KOH/g)
Water
Content Max. 30ppm
mg/kg (ppm)
(mg/kg)
for
bulk supply or
40ppm (mg/kg)
for delivery in
drums and IBC
Break
Down ≥
30
as
DES(kV at 2.5 mm delivered and ≥
gap)
50
after
treatment
Tan δ / Dielectric ≤0.005
Dissipation FactorDDF (at 40 to 60
Hz & 90 °C)
Oxidation Stability * see note
Corrosive Sulfur
Non corrosive
Anti-oxidant
As
agreed
Additives: Contents between
at least 0.15% by purchaser and
mass, but not more supplier
than 0.40% by mass
of (DBPC: 2.6-ditert-butylparacresole)
or
(DBP: 2.6-di-tertbutyl-phenol)
≤ 0.03
≤ 0.03
Max.
30ppm
(mg/kg) for bulk
supply or 40ppm
(mg/kg)
for
delivery
in
drums and IBC
≥ 30 as delivered
and ≥ 50 after
treatment
≤0.005
Max. 30ppm
(mg/kg)
for
bulk supply or
40ppm (mg/kg)
for delivery in
drums and IBC
≥
30 as
delivered and ≥
50
after
treatment
≤0.005
* see note
Non corrosive
As
agreed
between
purchaser
and
supplier
* see note
Non corrosive
As
agreed
between
purchaser and
supplier
* Note. In the case of inhibited oils only the induction period is determined
however in certain countries it is usual to determine also the DDF. In this case
the maximum value of DDF will be established by agreement between purchaser
and supplier. No limit for oxidation stability is specified. For guidance only.
Oils known to give satisfactory performance in transformers in service typically
have induction period in excess of 120 hours.
10
Table-9c: CHARACTERISTICS OF UNUSED MINERAL INSULATING OILS
FILLED IN NEW TRANSFORMERS: IEC 60422
CHARACTERISTICS OF
UNUSED MINERAL INSULATING OILS
FILLED IN NEW TRANSFORMERS: IEC 60422
Sr. Property
Highest Voltage for Equipment
No.
<72.5Kv
170kV
>170Kv
1
Appearance
Clear,
free Clear,
free Clear,
free
from
from
from
sediments and sediments and sediments and
suspended
suspended
suspended
matter
matter
matter
2
Colour
Max 20
Max 20
Max 20
3
3
Density kg/dm at 20 °C ≤0.895
≤0.895
≤0.895
(old Specific Gravity)
4
Interfacial
≥35
≥35
≥35
Tension/Surface Tension
(mN/m at 25 °C)
5a Kinematic
Viscosity ≤ 16.5
≤ 11
≤ 3.5
2
mm /s
at
40
°C
(Centistokes)
5b Kinematic
Viscosity ≤ 40
≤ 25
≤6
2
mm /s
at
20
°C
(Centistokes)
5c Kinematic
Viscosity ≤ 800
2
mm /s
at
-15
°C
(Centistokes)
5d Kinematic
Viscosity ≤ 1800
2
mm /s
at
-30
°C
(Centistokes)
5e Kinematic
Viscosity ≤ 150
2
mm /s
at
-40
°C
(Centistokes)
6
Pour Point °C
≤ -30
≤ -45
≤ -60
7
Flash Point °C
≥ 140
≥ 130
≥ 95
8
Neutralization
Value/ ≤ 0.03
≤ 0.03
≤ 0.03
Acidity (mg KOH/g)
9
Water Content mg/kg ≤ 20
≤ 15
≤ 10
(ppm)
11
10
Break Down DES(kV at
2.5 mm gap)
11 Resistivity at 90 °C
(GΩm)
12 Tan δ / Dielectric
Dissipation Factor-DDF
(at 40 to 60 Hz & 90 °C)
13 Oxidation Stability for
Uninhibited
OilNeutralization Value(mg
KOH/g)
13a Oxidation Stability for
Uninhibited OilSludge % by mass
14 Oxidation Stability for
Inhibited Oil- Induction
period (hours)
≥ 40
≥ 50
≥ 60
min 60
min 60
min 60
≤0.15
* see note
≤0.15
* see note
≤0.010
* see note
≤0.40
≤0.40
≤0.40
≤0.10
≤0.10
≤0.10
Similar value Similar value Similar value
as
before as
before as
before
filling
filling
filling
*Note. Higher DDF value may indicate excessive contamination or the
misapplication of solid insulation used in manufacturing and should be
investigated.
12
Table-9d: CHARACTERISTICS OF UNSUED MINERAL INSULATING OILS
FOR TRANSFORMERS AND SWITCHGEAR IEC 60296 (New specifications)
CHARACTERISTICS OF UNSUED MINERAL INSULATING OILS FOR
TRANSFORMERS AND SWITCHGEAR IEC 60296
Sr. Property
Unused Mineral Low
No.
Insulating Oil
Temperature
IEC 60296
Switchgear Oil
Function
1
Viscosity at 40 °C
Max. 12mm2 /s
Max. 3.5mm2 /s
2
Viscosity at -30 °C *see note
Max. 1800mm2 /s 3
Viscosity at -40 °C*see note
Max. 400mm2 /s
4
Pour Point*see note
Max. -40 °C
Max. -60 °C
5
Water Content
Max.
30ppm Max.
30ppm
(mg/kg) for bulk (mg/kg) for bulk
supply or 40ppm supply or 40ppm
(mg/kg)
for (mg/kg)
for
delivery in drums delivery in drums
and IBC
and IBC
6
Breakdown Voltage or DES at 2.5 Min. 30 kV before Min. 30 kV before
mm Gap
dehydration or 70 dehydration or 70
kV
after kV
after
dehydration
dehydration
7
Density at 20 °C (old S.G)
Max. 0.895 g/ml
Max. 0.895 g/ml
8
DDF at 90 °C (old Tan δ or DF)
Max. 0.005 (0.5%) Max. 0.005 (0.5%)
Refining/Stability
1
Appearance
Clear, free from Clear, free from
sediments
and sediments
and
suspended matter
suspended matter
2
Acidity
Max.
0.01mg Max.
0.01mg
KOH/g
KOH/g
3
Interfacial Tension (IFT)
Min. 40 mN/m
Min. 40 mN/m
4
Total Sulfur Content
No
general No
general
requirement
requirement
5
Corrosive Sulfur
No
general No
general
requirement
requirement
13
6
Antioxidant Additive
7
Furfural Content **see note
Performance
1
Oxidation Stability
2
Total Acidity
Uninhibited
oil
(U): Not detectable
Trace inhibited oil
(T): Max. 0.08%
Inhibited oil (I):
0.08 – 0.40%
Max. 0.1 mg/kg
Uninhibited
oil
(U): Not detectable
Trace inhibited oil
(T): Max. 0.08%
Inhibited oil (I):
0.08 – 0.40%
Max. 0.1 mg/kg
Max.
1.2mg Max.
1.2mg
KOH/g
KOH/g
3
Sludge
Max. 0.8%
Max. 0.8%
4
DDF at 90 °C (Dielectric Max. 0.500
Max. 0.500
Dissipation Factor) (Tan δ)
5
Gassing
No
general No
general
requirement
requirement
6
Electrostatic Charging Tendency Special
(ECT) ***see note
requirement
Health, Safety and Environment (HSE)
1
Flash Point
Min. 135 °C
Min. 100 °C
2
PCA
Content
(Polycyclic Max. 3%
Max. 3%
aromatics)
3
PCB Content (Polychlorinated Not detectable
Not detectable
biphenyls)
* Note. This is the standard LCSET (Lowest Cold Start Energizing Temperature)
for transformer oil and can be modified depending upon the climatic condition of
each country. Pour point should be minimum 10K below LCSET.
** Note. Furfural and related compounds (2-FAL) in unused mineral insulating
oils can result either from improper re-distillation after solvent extraction during
refining or from contamination with used oil. Unused insulating oils should have a
low level of 2-FAL and related compounds (IEC 1198).
*** Note. Electrostatic Charging Tendency (ECT) of oil is an important property
for certain designs of HV and EHV transformers which have oil pumping rates that
can give rise to the build-up of electrostatic charge. This charge can result in
energy discharge causing transformer failure. A method to measure ECT is
proposed by CIGRE SC 12.
14
Table-9e: CONCENTRATION OF DISSOLVED GASES (DGA) IN OIL (IEC
60567 &60599)
CONCENTRATION OF DISSOLVED GASES (DGA) IN OIL (IEC 60567
&60599)
Sr. Gas Description
Limiting Value Limiting Values
No.
(ppm v/v)
PTESU
Standard
(ppm)
1
Hydrogen (H2)
<200
<150
2
Methane (CH4)
<50
<25
3
Ethane(C2H6)
<15
<10
4
Acetylene (C2H2)
<15
<15
5
Ethylene (C2H4)
<60
<20
6
Carbon Mono oxide (CO)
<1000
<500
7
Carbon Dioxide (CO2)
<11000
<10000
8
Oxygen (O2)
2000-35000
9
Nitrogen (N2)
10000-100000
General criteria for interpretation on the bases of flame colour of combustible
gases detected in Buchholz Relay is as:
- If flame colour is Blue, it indicates decomposition of oil.
- If flame colour is Yellow, it indicates deterioration of solid insulation.
15
Table-9f: TREATMENT OF INSULATING OIL IN TRANSFORMERS
TREATMENT
OF
INSULATING
OIL
IN
TRANSFORMERS
RECOMMENDED REMEDIAL MEASURES
Characteristic
Recommended Measures
Description
Lower DES Value
Dehydration and Filtration
High Water/Moisture Dehydration and Filtration under Vacuum
Contents
High DDF (Tan δ)
Dehydration and Filtration under Vacuum OR
Regeneration/Reclamation/Replacement
Neutralization Value
Regeneration/Reclamation/Replacement
Interfacial Tension
Regeneration/Reclamation/Replacement
Essential Functions of Oil
- Dielectric Insulation
- Heat Transfer
Principal Causes of adverse changes in dielectric properties of Oil
- Oxygen and Humidity: Main source is the breathing system and oil leak points.
The desiccating material should be regenerated or renewed as soon as 1/3 rd of its
quantity has been moisturized (colour changed from blue to pink). Attend oil
leakages without intentional delays.
- High Temperatures
- External pollution
- Electrical phenomena
- Partial discharges
- Corona
16
Table- 9g: CHARACTERISTICS OF SULPHUR HEXAFLOURIDE GAS (S)
IEC 60376
CHARACTERISTICS OF SULPHUR HEXAFLOURIDE GAS (SF6) IEC
60376
Sr. Description
Limiting Value
Limiting Value
No.
(New/Unused Gas) (Gas in CB)
1
Purity (concentration of SF6 > 99.9%
> 95%
verses Nitrogen)
2
Dew Point (-°C)
-50°C
-10°C
3
Impurities
3a CF4 (Carbon Tetra-fluoride)
< 0.05% (m/m)
3b Oxygen + Nitrogen, air
< 0.05% (m/m)
3c Water
< 15ppm (m/m)
3d Acidity expressed as HF < 0.03ppm (m/m)
(Hydrofluoric acid)
3e Hydrolysable
fluoride < 1.0ppm (m/m)
expressed as HF
3f Oil content
< 10ppm (m/m)
Properties
-Sulphur Hexafluoride is a compound having the formula SF6
-At normal room temperatures and pressures it is gaseous
- It has density of 6.16g/l at 20 °C and 760 torr (about five times the density of air)
- Its critical temperature 45.6 °C, it can be liquefied by compression and is
normally transported as a liquid in cylinders
- Inert
- Colourless
- Odourless
- Nontoxic
- Nonflammable
- Good dielectric medium
- Electro-negative (tends to attract the free electrons), good arc quenching medium)
- High DES value, (about 3 times of the air at atmospheric pressure)
- Heat transfer capability 2-5 times of air
- Pressure increases with temperature by about 0.025 bar per °C
- Leakage detection possible with halogen gases leakage detectors
17
Preferred sizes of cylinders
-The standard sizes of cylinders, expressed in liters (l) for SF6 are: 3, 5, 10, 20, 40,
80, 150 and 500. 10 liter and 40 liter are the preferred size for use. The filling ratio
of cylinders in temperate countries is 1.04kg/l and in tropical countries is 0.75kg/l.
18
Table-9h: 500KV CIRCUIT
RESISTANCE DATA
BREAKERS
TIMING
AND
CONTACT
500KV CIRCUIT BREAKERS TIMING AND CONTACT RESISTANCE
VALUES (H: Hydraulic, S: Motor Spring, P: Pneumatic Operating
Mechanisms)
Sr. Make
Type
Closing
Opening
Contact
No.
Time (ms)
Time (ms)
Resistance
(Maximum) (Maximum) micro
Ω
per Pole
(Maximum)
1
SIEMENS (H) SF6 3AT5
(4 90±10
18±3
240
Breaks per
Pole)
2
SIEMENS (H) SF6 3AT4
(4 90±10
18±3
240
Breaks per
Pole)
3
SIEMENS (H) SF6 3AT3E1 (2 80±6
18±2
75±5
Breaks per
Pole)
4
SIEMENS (H) SF6 3AT2E1 (2 80±6
18±2
75±5
Breaks per
Pole)
5
SIEMENS (H) SF6 8DQ14 (2 80±6
18±2
75±5
(GIS)
Breaks per
Pole)
6
MERLIN GERIN FA4
(4 42±4
19±4
250
(H) SF6
Breaks per
Pole)
7
MERLIN GERIN FA4R (4 42±4
19±4
250
(H) SF6
Breaks per
Pole)
8
MERLIN GERIN GFA2R (4 42±4
19±4
250
(H) SF6
Breaks per
Pole)
9
MERLIN GERIN GFA4R (4 42±4
19±4
250
(H) SF6
Breaks per
Pole)
10 TOSHIBA (H) SF6 GSR100
18
100
19
11
12
13
14
15
16
17
18
19
20
500R2
TOSHIBA (H) SF6 GSR100
500R2C
HITACHI (H) SF6 OFTB
500/40L
GEC ALSTHOM FX32D
(H) SF6
GEC ALSTHOM FX22Z
(H) SF6
MITSUBISHI (P) 500
SF6
SFMT/50B
ABB (S) SF6
HPL 550 65
B2
(4
Breaks per
Pole)
AEG (P) SF6
S4M-550P 100
AREVA(S) SF6
GL317D
(FK3-4)
ASEA (S) SF6
HPL 550/
4004LT
DELLE
PK6C
ALSTHOM
(ABCB)
18
100
19±3
80
25
200
450
20
Table-9i: 220KV CIRCUIT
RESISTANCE DATA
BREAKERS
TIMING
AND
CONTACT
220KV CIRCUIT BREAKERS TIMING AND CONTACT RESISTANCE
VALUE (H: Hydraulic, S: Motor Spring, P: Pneumatic Operating
Mechanisms)
Sr. Make
Type
Closing
Opening
Contact
No.
Time (ms)
Time (ms)
Resistance
(Maximum) (Maximum) micro
Ω
per Pole
(Maximum)
1
SIEMENS (H) SF6 3AQ1E1 (1 95±5
39±3
60
Break per
Pole)
2
SIEMENS (S) SF6 3AP2F1 (2 63±6
18±2
54±5
Breaks per
Pole)
3
SIEMENS (S) SF6 3APF1 (1 62±6
37±4
40
Break per
Pole)
4
SPRECHER
HGF150
28
50
ENERGIE (S) SF6 100/1A (1
Break per
Pole) FKF
1-2
5
MERLIN GERIN FA2
(2 100
30
170
(H) SF6
Breaks per
Pole)
6
MERLIN GERIN FA2R (2 100
30
170
(H) SF6
Breaks per
Pole)
7
MERLIN GERIN FA1
(1 100
30
170
(H) SF6
Break per
Pole)
8
CHINA (H) OCB
SW6-245
200
40
400
(2 Breaks
per Pole)
9
NMG (P) SF6
245-MHM- 100
30
50
e-1P
(1
21
10
11
12
13
14
15
16
17
18
19
Break per
Pole)
BBC (P) SF6
ELVF-245
nc2at
(2
Breaks per
Pole)
ABB (H) SF6
ELF SP4-1
(1
Break
per Pole)
ABB (S) SF6
LTB245E1 (2
Breaks per
Pole)
ABB (S) SF6
HPL
245/31B1
(2 Breaks
per Pole)
ABB (S) SF6
HPL
245/3152
(2 Breaks
per Pole)
AEG (S) SF6
S1-245/F3
(2 Breaks
per Pole)
AEG (P) SF6
S1-245 (1
Break per
Pole)
ALSTHOM
(S) GL-314 (1
SF6
Break per
Pole) FK31
NMG/VATECH
SB6m-245
(S) SF6
(1
Break
per Pole)
CHEM China (S) OFPI-252SF6
50L, FAR
(1
Break
per Pole)
110
20
100
55
18
60
63±6
18±2
54±5
63±6
18±2
54±5
63±6
18±2
54±5
63±6
18±2
54±5
63±6
18±2
54±5
82-102
16-26
50
75±5
30±3
40±5
≤ 80
≤ 30
≤ 30
22
Table-9j: 132KV CIRCUIT
RESISTANCE DATA
BREAKERS
TIMING
AND
CONTACT
132KV CIRCUIT BREAKERS TIMING AND CONTACT RESISTANCE
VALUE (H: Hydraulic, S: Motor Spring, P: Pneumatic Operating
Mechanisms)
Sr. Make
Type
Closing
Opening
Contact
No.
Time (ms) Time (ms) Resistance
(Maximum (Maximum micro
Ω
)
)
per Pole
(Maximum
)
1
SIEMENS
(H) 3ARI
(1 100±5
50±5
60
SF6
Break
per
Pole)
2
SIEMENS
(H) 3AQI
(1 95±5
39±3
60
SF6
Break
per
Pole)
3
SIEMENS
(S) 3API FG (1 57±6
31±3
40
SF6
Break
per
Pole)
4
ENERGOINVES SFE-13
(1 130
35
60
T (P) SF6
Break
per
Pole)
5
S&S (S) SF6
HGF-112/1C 140
25
60
(1 Break per
Pole) FKF2-6
6
AEG (P) SF6
S1-145
(1 100
40
60
Break
per
Pole)
7
AEG (S) SF6
S1-145
100
40
60
F1/3131/SE
(1 Break per
Pole) CRR-5
8
AEG (S) SF6
S1-145
100
40
60
F1/4031/SE
(1 Break per
Pole) CRR-5
9
ASEA (S) SF6
HPL-145/25 90
21±2
50
23
10
11
12
13
14
15
16
17
18
20
21
A1 (1 Break
per
Pole)
BLG 1002
ABB (S) SF6
HPL-145/25
A1 (1 Break
per
Pole)
BLG 1002
ABB (S) SF6
HPL-145/25
A1 (1 Break
per
Pole)
BLG 1002A
NMG (S) SF6
1M-MHD145 (1 Break
per Pole)
MITSUBISHI (S) SFM-145 (1
SF6
Break
per
Pole)
BBC (H) OCB
TR-145
(1
Break
per
Pole)
BBC (H) OCB
TR-170
(1
Break
per
Pole)
LKNES (H) OCB MULB-150
(1 Break per
Pole)
ASEA (S) OCB
HLD145/1250b (1
Break
per
Pole)
CHINA (H) OCB SW6-145 (2
Break
per
Pole)
BBC (P) SF6
ELF-145n1
(1 Break per
Pole)
ABB (H) SF6
SL 2-1 (1
Break
per
Pole)
90
21±2
50
90
21±2
50
80
250
60
130
28
100
75±10
35±10
150
75±10
35±10
150
130
50
150
90
46
150
200
40
180
110
20
50
55
18
60
24
22
22
23
24
25
ABB (S) SF6
LTB145D1/B (1
Break
per
Pole)
ABB (S) SF6
LTB145D1/B (1
Break
per
Pole)
CAPACITO
R BANK
ALATOM
(S) GL-212
(1
SF6
Break
per
Pole) FKPIN DING SHAN LW 35-145
CHINA (S) SF6
(1 Break per
Pole)
TENAGA (S) SF6 LW9-145 (1
Break
per
Pole)
42
22±4
40
A/B/C:
45/40/40
22±4
40
100±5
50±5
60
100±20
28 +2 -4
45
150
30
45
≤ 30
≤ 30
CHEM China (S) OFPI-145≤ 100
SF6
40L, FAR3
(1 Break per
Pole)
25
Table-9k: 66KV CIRCUIT
RESISTANCE DATA
BREAKERS
TIMING
AND
CONTACT
66KV CIRCUIT BREAKERS TIMING AND CONTACT RESISTANCE
VALUE (H: Hydraulic, S: Motor Spring, P: Pneumatic Operating
Mechanisms)
Sr. Make
Type
Closing
Opening
Contact
No.
Time (ms)
Time (ms)
Resistance
(Maximum) (Maximum) micro
Ω
per Pole
(Maximum)
1
ENERGOINVEST SFE-9 (1 130
35
60
(P) SF6
Break per
Pole)
2
ABB (S) SF6
LTB-72.5
42
22±4
40
D1/B
(1
Break per
Pole)
3
CHINA (H) OCB
SW6-72.5 200
40
180
(2
Break
per Pole)
26
Table-9l: LEAD ACID DC BATTERIES OPERATION AND MAINTENANCE
DATA
Sr.
No.
Battery Make
Battery
Type
Rated
Capacity
(AH)
Float
Charge
VPC
(V)
Boost
Charge
VPC
(V)
Sp.
Gravity
at 25°C
End
of
Discharge
Voltage at
10
hours
rate (V)
1
YUASA
(Japan)
YUASA
(Japan)
ROCKET
(Korea)
ROCKET
(Korea)
VARTA
(Germany)
VARTA
(Germany)
CS-170
150
2.12
2.33
1.180±
0.1C/1.80
Average
Impedance
Per
Cell
(mΩ)
(Empirical
Values0
1.44
CS-400
300
2.12
2.33
1.180±
0.1C/1.80
0.640
PS-170
150
2.15
2.40
1.180
0.1C/1.80
1.22
PS-400
300
2.15
2.40
1.180
0.1C/1.80
0.658
OPZS
150
2.23
2.40
1.180
0.1C/1.80
1.44
OPZS
600
2.23
2.40
1.180
0.1C/1.80
0.407
TUDOR (Italy)
TUDOR
(Sweden)
NAMBANG
(Korea)
HOPPECKE
(Germany)
CHLORIDE
(England)
CHLORIDE
(England)
DUROS
(Denmark)
BERGA
(Germany)
FIAMM (Italy)
FIAMM (Italy)
CHLORIDE
(Pakistan)
EXIDE
(Pakistan)
EXIDE
(Pakistan)
6TF
GR200/
3GR200
PS
150
300
2.22
2.17
2.40
2.40
1.180
1.180
0.1C/1.80
0.1C/1.83
1.30
0.731
150
2.17
2.40
1.180
0.1C/1.80
0.731
2.23
2.40
1.220
0.1C/1.80
0.731
150
2.21
2.35
1.203
0.1C/1.85
0.641
300
2.21
2.35
1.203
0.1C/1.85
0.378
150
2.20
2.40
1.240
0.1C/1.80
0.731
Gro
475
2.23
2.40
1.220
0.1C/1.80
0.315
SM4
SM4
1XMP
150
300
150
2.18
2.18
2.18
2.40
2.40
2.40
1.180
1.180
1.180
0.1C/1.80
0.1C/1.80
0.1C/1.80
0.471
0.238
0.471
1XMP19
1XMP33
150
2.20
2.40
1.180
0.1C/1.80
0.725
150
2.20
2.40
1.180
0.1C/1.80
0.352
1
2
2
3
3
4
4
5
6
7
7
8
9
10
10
11
12
12
Gro E25
YCP25/AE
YCP13/AF
Note-1. Correction of Specific Gravity at temperature 25 °C: S25 = St + 0.0007 (t – 25)
S25 = Corrected Specific Gravity at temperature 25 °C
St = Measured Specific Gravity at temperature t °C of electrolyte
t = Temperature of electrolyte (°C) as measured at site
Where
27
Note-2. Open Circuit Voltage Per Cell = Specific Gravity + 0.84 Volts
Note-3. End of Discharge Specific Gravity = 1.415
Note-4. Average Impedance of Strap/Inter-cell Connector = 0.24 mΩ
28
Table-9m: CAPACITANCE AND DISSIPATION FACTOR VALUES OF
132/11KV POWER TRANSFORMERS
Sr.
No.
TR Make
TR Type
1
SHENYANG
(China)
SFZ726000
2
2
2
3
4
4
5
6
7
TR
Ratings
20/26
MVA
132/11KV
SHENYANG SFZ720/26
(China) *
13000
MVA
132/11KV
TOSHIBA
HC/OPTL 20/26
(Japan)
R-D
MVA
132/11KV
TOSHIBA
HC/OPTL 10/13
(Japan) *
R-D
MVA
132/11KV
MINEL
TPv20/26
(Yugoslavia)
7105-26
MVA
132/11KV
ELTA
TNARC- 20/26
(Poland)
26000/13 MVA
2 PT
132/11KV
ELTA
TNARC- 10/13
(Poland) *
13000/13 MVA
2 PT
132/11KV
HYUNDAI
TL-068
20/26
(Korea)
MVA
132/11KV
OTE (Italy)
BERGA
10/13
MA
MVA
132/11KV
ELECTROPU
20/26
TRE
MVA
(Romania) *
132/11KV
Winding
Tested
C Value
(PF)
(Empiric
al Value)
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
4270
3379
7636
4270
3379
7636
4063
3297
8170
4063
3297
8170
4113
3364
8448
5400
2949
13110
5400
2949
13110
5400
3480
9386
3882
3007
6456
4270
3379
7636
%DF
Value
at 20 °C
(Empiri
cal
Value)
0.615
0.528
0.578
0.615
0.528
0.578
0.138
0.125
0.29
0.138
0.125
0.29
0.295
1.309
0.705
0.2
0.3
0.3
0.2
0.3
0.3
0.249
0.23
0.26
0.375
0.324
0.504
0.615
0.528
0.578
29
8
9
ELECTROPU
TRE
(Chec
Republic)
SIEMENS
(Pakistan) *
10
SIEMENS
(Pakistan) *
12
SIEMENS
(Pakistan) *
13
HEC
(Pakistan) *
14
PEL
(Pakistan) *
15
PEL
(Pakistan) *
16
PEL
(Pakistan) *
17
IRANTRAFO
(Iran) *
4
MEIDENSHA
(Japan) *
4
MEIDENSHA
(Japan) *
4
ELPROM
(Bulgaria) *
4
```
10/13
MVA
132/11KV
40
MVA
132/11KV
H-L
H-G
L-G
H-L
H-G
L-G
20/26
H-L
MVA
H-G
132/11KV L-G
20/26
H-L
MVA
H-G
132/11KV L-G
20/26
H-L
MVA
H-G
132/11KV L-G
40
MVA H-L
132/11KV H-G
L-G
20/26
H-L
MVA
H-G
132/11KV L-G
10/13
H-L
MVA
H-G
132/11KV L-G
20/26
H-L
MVA
H-G
132/11KV L-G
20/26
H-L
MVA
H-G
132/11KV L-G
10/13
H-L
MVA
H-G
132/11KV L-G
20/26
H-L
MVA
H-G
132/11KV L-G
20/26
`
MVA
132/11KV
4296
2477
7845
4270
3379
7636
4270
3379
7636
4270
3379
7636
4270
3379
7636
4270
3379
7636
4270
3379
7636
4270
3379
7636
4270
3379
7636
5400
2949
13110
5400
2949
13110
5400
2949
13110
````````````
```````````
0.46
0.75
0.35
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.2
0.3
0.3
0.2
0.3
0.3
0.2
0.3
0.3
`
30
4
GANZ
(Hungary) *
``````
4
PAUWELS
(Belgium) *
DRF130/275
(3-WDG)
20/26
MVA
132/11KV
37.5 MVA
132/66/11
KV
H-L
H-G
L-G
H-L
H-G
L-T
L-G
H-T
T-G
5400
2949
13110
5994
4413
7078
2041
40
15860
0.2
0.3
0.3
0.478
0.53
0.478
0.52
0.688
31
Table-9n: CAPACITANCE AND DISSIPATION FACTOR VALUES OF
220/132/11KV AUTO TRANSFORMERS
Sr.
No.
TR Make
TR
Type
TR Ratings
Windin
g
Tested
C Value
(PF)
(Empirica
l Value)
1
CEM
(France)
AOTR.
CV
2
SHENYAN
G (China)
3
HAWKER
SIDDELY
(UK)
ALSTHOM
(France)
OSFPS7160000
HSPT/T
TT85
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
250
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
HL-T
HL-G
T-G
HL-T
HL-G
T-G
HL-T
HL-G
T-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
4732
6374
10530
5778
7428
14496
14303
27637
24973
10400
7800
11600
8500
6700
13800
5600
5700
13200
4270
3379
7636
4270
3379
7636
4270
3379
7636
4270
3379
7636
4270
4
AUTO
5
AEG
(Turkey)
MRSN8254
6
BBC
(Germany)
AUTO
7
TBEA
(China) *
8
TBEA
(China) *
9
HOUPING
(China) *
10
SHENBIAN
(China) *
11
ABB (Spain)
%DF
Value at
20
°C
(Empirica
l Value)
0.74
0.95
0.88
1.61
0.65
1.60
0.345
0.358
0.360
0.202
0.328
0.38
0.358
0.386
0.775
0.319
0.324
0.312
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
32
*
12
HYUNDAI
(Korea) *
13
SIEMENS
(Pakistan) *
14
ABB
(Germany) *
15
MEIDENSH FBORS
A (Japan)
DL
16
ABB
(Germany)
MANGLA
TPFD
66 000
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
160
MVA
220/132/11K
V
138
MVA
220/132/11K
V
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
H-L
H-G
L-G
HL-T
HL-G
T-G
HL-T (3
HL-G (5
T-G (4)
3379
7636
4270
3379
7636
4270
3379
7636
4270
3379
7636
6832
7460
14846
6289
5864
12158
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.615
0.528
0.578
0.3
0.165
0.66
1.085
0.87
0.98
33
Table-9o: CAPACITANCE AND DISSIPATION FACTOR VALUES OF
500/220/22KV AUTO TRANSFORMERS
Sr.
No.
TR Make
1
TRAFOUNIO NRPN 600 (200x3)
N (Germany) -8157 MVA
500/220/22
KV
JEMOUNT
AUTO 450 (150x3)
SCHENIDER
MVA
(France)
500/220/22
KV
TBEA
450 (150x3)
(China) *
MVA
500/220/22
KV
SIEMENS
NRPN 600 (200x3)
(Brazil) *
-8157 MVA
500/220/22
KV
SIEMENS
NRPN 600 (200x3)
(Germany) * -8157 MVA
500/220/22
KV
TBEA
200 (200x3)
(China) *
MVA
500/220/22
KV
ELIN
450 (150x3)
(Austria) *
MVA
500/220/22
KV
2
3
4
5
6
7
TR
Type
TR Ratings
Windin C Value
g Tested (PF)
(Empirica
l Value)
HL-T
HL-G
T-G
4196
4173
9722
%DF
Value at
20
°C
(Empirica
l Value)
0.133
0.131
0.255
HL-T
HL-G
T-G
7200
5700
10800
0.32
0.205
0.531
HL-T
HL-G
T-G
4270
3379
7636
0.615
0.528
0.578
HL-T
HL-G
T-G
4196
4173
9722
0.133
0.131
0.255
HL-T
HL-G
T-G
4196
4173
9722
0.133
0.131
0.255
HL-T
HL-G
T-G
4270
3379
7636
0.615
0.528
0.578
HL-T
HL-G
T-G
4270
3379
7636
0.615
0.528
0.578
34
Table-9p: CAPACITANCE AND DISSIPATION FACTOR VALUES OF
CONDENSER TYPE BUSHINGS OF TRANSFORMERS
Sr.
No.
Bushing
Make
Type
Rated
Voltage
Insulati
on
Tested
C Value
(PF)
(Empirica
l Value)
1
HAFELY
(Swiss)
HAFELY
(Swiss)
F&G
(Germany)
F&G
(Germany)
PASSONI&V
ILLA (Italy)
PASSONI&V
ILLA (Italy) *
ABB
(Sweden)
ABB
(Sweden)
ABB
(Sweden)
BRUSH
(UK)
MICAFIL
(Swiss)
NGK (Japan)
COT-245
220KV
COT-145
145KV
OTF1550/525
OTF1050/245
PNE145/400A
PNE245/400A
GOM-1050
500KV
GOB-650
132KV
GOB-380
100KV
OV-1451000
132KV
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
H-L
H-G
405
10840
335
11115
414.5
7828
427
7828
235.95
235.95
483.25
309.55
353.1
375.8
405
10840
2
3
4
5
6
7
8
9
10
11
12
220KV
145KV
145KV
220KV
220KV
%DF
Value at
20
°C
(Empirica
l Value)
0.68
1.94
0.58
1.26
0.03
0.36
0.065
0.355
0.79
0.79
0.774
0.687
0.687
0.25
0.68
1.94
132 KV
35
Table-9q: CAPACITANCE AND DISSIPATION FACTOR VALUES OF
CURRENT TRANSFORMERS (C.T)
Sr.
No.
CT Make
Type
Rated
Voltage
Insulatio C Value
n Tested (PF)
(Empiric
al Value)
1
MESSWAND
LER
(Germany)
EMEK
(Turkey)
EMEK
(Turkey)
SITW (China)
AT-145
132KV
H-G
500
%DF
Value at
20
°C
(Empirica
l Value)
0.2
AT4-145
132KV
H-G
307.5
0.29 (<1)
AT4-245
245KV
H-G
206.6
0.02 (<1)
LCWB6145
FGCH-200
132KV
H-G
900
0.8 (<2)
900
0.2 (<1)
634
0.6
800
22000
800
13000
1000
170
500
(<1)
(<1)
(<1)
(<1)
(<1)
350
0.2
2
3*
4
5
NISSIN
220KV
H-G
(Japan)
6
GALILEO
TAE-245/G 220KV
H-G
(Italy)
7 ** ASEA
IMBD-145 132KV
C1 (H-L)
(Sweden)
C2 (H-G)
8 ** ASEA
IMBD-72
66KV
C1 (H-L)
(Sweden)
C2 (H-G)
9
HAEFELY
ISOK-245 220KV
H-G
*** (Swiss)
CA
10
LK-NES
A8z61/A9z 132KV H-G
(Denmark)
61
11
MESSWAND JOS-72.5
66KV
H-G
LER
(Germany)
12
NIROU
TRANS
(Iran)
Note. *: Top and Bottom units should be tested separately.
Note. **: Use capacitance tap for test.
Note. ***: CA means the bushing capacitance.
0.2
36
Table-9r: CAPACITANCE AND DISSIPATION FACTOR VALUES OF
CAPACITOR VOLTAGE TRANSFORMERS (CVT)
Sr.
No.
CVT Make
Type
Rated
Insulati C Value (PF) %DF
Voltage on
(Empirical
Value
Tested Value)
at 20
°C
(Empir
ical
Value)
1
TRENCH
ELECTRIC
(Canada)
GALILEO
(Italy)
TEHM-500
500KV
TCS-245G
220KV
3
NMG
(Italy)
CPTa-245/4
220KV
4
HAEFLY
(Swiss)
CVE-245
220KV
5
TRENCH
ELECTRIC
(Canada)
MAGRINI
GALILEO
(Italy)
PASSONI
&VILLA
(Italy)
HAEFLY
(Swiss)
TEM-L3OS
220KV
CPT-245/8
220KV
CVE-550
500KV
9
EMEK
(Turkey)
KGT-245
10
EMEK
(Turkey)
KGT-145
12
NIROU
TRANS
(Iran) *
2
6
7
8
CN(H-G)
C1
C2
CN(H-G)
C1
C2
CN(H-G)
C1
C2
CN(H-G)
C1
C2
CN(H-G)
C1
C2
CN(H-G)
5000
5300
133900
8000
0.24
4000
4400
44000
4500 +10% -5%
4790 +10% -5%
74455+10% -5%
3000
(<1)
8000 ±10%
(<1)
7000 +10% -5%
(<1)
6900 +10% -5%
7033 +10% -5%
27176 +10% -5%
4598
(<1)
220KV
CN(H-G)
C1
C2
CN(H-G)
C1
C2
CN(H-G)
132KV
CN(H-G)
5950
(<1)
500KV
(<1)
(<1)
(<1)
(<1)
220KV
37
12
NIROU
TRANS
(Iran) *
132KV
38
Table-9s: LEAKAGE CURRENT MONITORING (LCM)
ARRESTERS/LIGHTNING ARRESTERS
OF
SURGE
Sr. Make
No.
Type
Rated Mfr.
MCOV Total
Resistive
Voltage Rated
Leakage Leakage
Voltage
Current Current
1
ZLAX25C
ZLAX15C
XAA
220KV
198KV
154KV
< 800µA
< 200µA
132KV
120KV
90KV
< 350µA
< 200µA
132KV
116KV
90KV
-
< 200µA
ZSE-C1Z
220KV
198KV
154KV
< 490µA
< 200µA
ZSE-C1Z
132KV
120KV
90KV
< 390µA
< 200µA
1MB-120
132KV
120KV
90KV
-
< 200µA
9LXBH60 220KV
198KV
160KV
-
< 200µA
EXLIMQ
220KV
198KV
160KV
< 1000µA
< 200µA
Y10W120/295
YHO
10W12/38
132KV
120KV
90KV
-
< 200µA
12KV
-KV
-KV
-
< 200µA
2
3
4
5
6
7
8
9
10
HITACHI
(Japan)
HITACHI
(Japan)
ASEA
(Sweden)
MEIDENSHA
(Japan)
MEIDENSHA
(Japan)
BOWTHORP
(England)
GE/TRANQUELL
(USA)
ABB
(Sweden)
WENZHOU
YIKUN (China)
WENZHOU
YIKUN (China)
39
Table-9t: CRITERIA FOR REPLACEMENT OF VACUUM INTERRUPTER
IN 11KV VACUUM CIRCUIT BREAKERS (VCB)
Sr. VCB Make
No.
Type
No.
of Description (to be checked
Operations in CB closed position)
1
MEIDENSHA
(Japan)
MEIDENSHA
(Japan)
SIEMENS
(Pakistan)
HITACHI
(Japan)
AEG
(Pakistan)
TOSHIBA
(Japan)
VFT-12 (O/G)
10,000
VE-14 (I/C)
10,000
3AF
30,000
V
10,000
VA
30,000
VK
30,000
7
J&P (Japan)
BK
10,000
8
HYUNDAI
(Japan)
PELKA/PEL
(Turkey/Pak)
PELKA/PEL
(Turkey/Pak)
2
3
4
5
6
9
10
When limit of contact wipe
reaches to 1mm (normal 4mm)
When wear standard line coincide
with the flange face
When white check mark becomes
invisible
When distance between the
reference lines exceeds 1mm
When burn-off indicator becomes
invisible
When limit of red-painted limit
of contact wipe decreases to less
than 3mm
When contact wear reaches
3mm/Gap reduces to 1mm (to be
checked by measuring the snatch
gap)
10,000
PDB5-25-8W
(O/G)
PDB5-25-25W
(I/C)
11
A vacuum interrupter (vacuum bottle) of 11kV VCB should be replaced when any one of the
following criteria is met with:
- The prescribed number of total operations have been completed (operation counter reading)
- Failed in vacuum degree check/test (tested with proper test set VIDAR or when tested with
Hipot set).
- Limit of contact wipe reached (abnormal wear of contacts).
Note. Vacuum degree test / Limit of contact wipe should be checked yearly or after 1000
operations whichever comes first.
40
10. OPERATION
A view of 220/132kV Control Room of 220kv G/S NKLP Lahore
41
10.1 INTRODUCTION
The grid stations in grid system of NTDCL&DISCOs are designed and constructed for
operation, supervision and control by the staff round the clock, unlike the grid system of
many developed countries where the grid stations are remote operated, supervised and
controlled at central control centers.
The operation staff at control rooms of grid stations comprises shift engineers, operators,
attendants, etc. and perform duty in three shifts i.e. morning shift, evening shift and night
shift. The operation staff supervises and controls the grid station in accordance with the
provisions made in the design and construction of the equipment and transmission lines
and in compliance of the instructions of the system operator, i.e. NPCC & RCC.
The operation staff records hourly loading data (Amperes), voltage data (kV), temperature,
and other parameters, etc. of the transformers and transmission line in the station log sheet
and onward passes to NPCC and/or RCC. They also maintain the record of all the normal
and abnormal events of the local system and record of telephonic instruction of all the
stakeholders of the system for reference. They coordinate with NPCC and/or RCC and
manage the scheduled and non-scheduled shut-downs on the grid station equipment and
transmission lines, for maintenance and other purposes. They perform switching
operations of the switchgear as desired under instructions of NPCC and/or RCC.
42
10.2 General Provisions
Generally operations mean all types and categories of work to be done by the
employees of NTDCL&DISCOs assigned to them as a duty. These operations include
technical, administrative, finance, etc. duties with the ultimate goal to build, operate
and maintain the power system for transmission and dispatch of electricity to the
distribution companies and down to the consumers. Generally the operations are
planned but it may include unplanned work activities as desired by
NTDCL&DISCOs. All the operation in-charges should give proper attention for
safety of the NTDCL&DISCOs employees during operations at NTDCL&DISCOs
premises. The operations in NTDCL&DISCOs are integrated as under:
a) Operation of power system for generation, transmission and dispatch of electricity
to the Distribution Companies (DISCOs) is a planned action by NTDCL. National
Power Control Center (NPCC) Islamabad (including Regional Control Centers (RCC)
North & South is the authorized System Operator on behalf of NTDCL.
b) NPCC/RCC shall be responsible for the safe, secure, openly-accessible, equitable,
environmentally acceptable, reliable and adequate operation and development of the
power system. The Operation Codes of NEPRA Grid Code and Distribution Code
outlines the necessary rules for operation of the NTDCL&DISCOs power system
which should be followed as and where applicable.
c) It is the primary responsibility of each employee of the NTDCL&DISCOs to keep
the NTDCL&DISCOs system and its component apparatus/equipment in safe
operating condition within their design parameters.
d) No employee shall operate any apparatus or equipment without having
authority/permission or instructions from the competent authority.
e) In the existing set up of NTDCL&DISCOs, NPCC is the System Operator of the
entire Grid System. In addition to the specific and general instruction of the NPCC
whether written or oral, the guidelines given here under shall be followed by all
NTDCL&DISCOs employees engaged in operation and maintenance work at different
levels of GSO NTDCL&DISCOs such as;
- Dealing operation of the HV equipment,
- Issuing operating orders and messages,
- Dealing with authority to work, Permit-to-Work and Hold-OFF orders,
- Dealing with office work and record of operations, etc.
- Recording data in the grid station daily log sheets, etc.
43
f) The employees of NTDCL&DISCOs and public should clearly understand the
application and significance of operating voltage levels of different equipment or
apparatus as given below with regards to their own safety as well as of the
apparatus/equipment.
- Control and Auxiliary Services Voltages:
24VDC, 48VDC, 110VDC and 220V DC;
110VAC, 230VAC, 400VAC, 50 Hz;
- Three-phase four-wire 400VAC and 230VAC, 50 Hz are the domestic and
commercial supply voltage levels in Pakistan.
- Medium Voltages (MV) for transmission and distribution:
11kV, 22kV (tertiary voltage of EHV transformers) and 33kVAC, 50Hz;
- High Voltages (HV) for transmission: 66kV and132kV AC, 50 Hz;
- Extra High Voltages (EHV) for transmission: 220kV and 500kV AC, 50 Hz.
g) Switching operations: The operation in-charge is responsible to ensure safety of the
employees as well of the NTDCL&DISCOs equipment during their normal as well as
emergency operations. Similarly, the operation staff on duty besides to look after the
normal operations of the grid station equipment have to do switching operation. To
deal with switching operations of the HV equipment safely the operation in-charge or
the shift in-charge will follow as under before, during and after switching operations:
- He will ensure for the approval of the desired operations of the equipment from
NPCC/ RPCC.
- He will inform and discuss with the NPCC/RPCC any abnormal local condition of
the equipment to be operated.
- He will identify the nature of operations and safety precautions required.
- He will identity the operations during which workers are/or can be exposed to
hazards.
- He will ensure for the clear operation instructions.
44
- He will follow the prescribed procedure and instructions given in the PTW (Permit
to Work) for its issuance and cancellation.
- In case of maintenance work oriented operations, he will get complete information
about the work to be done from the concerned supervisor and make sure that the
equipment to be work upon is fully isolated from all possible sources of supply. He
will issue PTW to the authorized supervisor for execution of the work in question
indicating all the hazards known to him and not eliminated or covered by the PTW
and also discus with the supervisor.
- During the switching operations, he will continuously keep contact with
NPCC/RPCC and make sure that all the operations are carried out in the approved
sequence.
- Satisfactory operations will be brought to the notice of NPCC/RCC regularly and
abnormal situation if any will also be brought to the notice of NPCC/RCC
immediately.
- He will make sure that no equipment in the system gets over loaded beyond their
rating as a result of operations under execution.
- After satisfactory completion of the switching operations to be carried out he will
inform to the NPCC/RPCC about the post operation system condition.
- He will make entries of the switching operations in the substation order book for
reference and record and place Caution Notice/Tag on the control switches of all
equipment which may energize the point of work.
- After completion of the work and obtaining clearance from the PTW holder he will
cancel the PTW following the prescribed procedure and instruction and inform the
NPCC/RPCC for further instruction to normalize the system.
h) As the operations include technical, administrative, finance, etc. duties, therefore while
working in NTDCL&DISCOs offices the office in-charges are responsible to manage for a
neat, clean, safe and comfortable atmosphere. Do not use the broken furniture and office
tools, etc. Do not hold paper pins, clips, etc. in the mouth and also do not use them as
tooth-picks or for cleaning ears. While working on old damped record files take care of
insects, dust/dirt, etc. Do not smoke and use open flames in the record rooms.
45
10.3 NPCC SOP FOR SYSTEM RELIABILITY AND SECURITY (issued by NPCC
Islamabad in September 2006)
Following criteria must be followed by the Dispatcher/System Operators for reliability and
Security of the system to avoid blackout/major collapse.
1. While allowing shutdown especially on 500kV transmission lines it must be ascertained
that even after the outage, n-1 contingency criteria is not violated, either directly or
through cross trip schemes.
2. While allowing shutdown on any 500kV auto transformers, n-1 contingency criteria
may not be violated.
3. Before permitting shutdown, the load-shedding may be implemented so that the loading
of the system remains within the safety criteria all the time.
4. The system frequency control must be with hydel stations i.e. Mangla/Tarbela in all
seasons for effective control. It may be achieved even at the cost of water spillage/hydel
energy.
5. Spinning must be made available at all times so the system can have some reserve to
meet with eventualities. The spinning must be as per the standard rule of being equal to the
largest unit on bar i.e. about 400MW is required round the clock. Spinning should be on
units that have a high pick up.
6. Frequency of the system should be maintained within the specified limit i.e. ±1%
7. Cross-trip schemes must be revised and implemented according to seasonal load flow
pattern.
8. Economic consideration must not supersede the reliability, safety and security standards.
9. The system voltages should not be allowed to drop below 5% allowable limit in normal
circumstances and to meet the criteria, extra generation be taken on bar or load shedding
implemented, if other measures to boost the voltage have exhausted.
10. In case of 500kV transformers, the loading should be kept within 100% normally, as
outage of transformers at any big station cab also result in blackout on the system,
however, short time overloading as per approved criteria may be allowed keeping in view
oil/winding temperature.
46
10.4 CONTINGENCY PLAN FOR BLACK START OF TARBELA POWER
STATION (issued by NPCC Islamabad in October 2006)
This plan is useful in restoration of station auxiliary supply and helps prompt restoration of
the system as well.
1. Don’t panic please.
2. Open 220kV circuit breaker D7Q1, D7Q2 and D7Q3 to isolate 220kv and 500V system
at Tarbela.
3. Open 220kV lines circuit breaker for all the lines, if they are in closed position.
4. Start Diesel Generation No: 1 & 2
5. Open all 11kV station supply circuit breakers EXCEPT 11kV BREAKER No. 1 & 28
on 11kV flank A & B respectively.
6. Close 11kV circuit breakers of Diesel Generator No. 1 & 2, Power Supply for Unit
auxiliaries will appear on respective RPDC for Units (1-4).
7. Isolate both the 220kV bus bars.
8. Start any of the Unit 1-4 on “Manual Mode” and build up rated voltage after ensuring
that NO INDICATION PERSISTS IN Control Room.
9. Close the relevant circuit breaker Q2 of the unit to connect it with 220kV Bus Bar No. 2.
Now Bus Bar No. 2 is energized.
10. Open 11kV incoming circuit breaker for both the Diesel Generator sets.
11. Close 220kV circuit breaker D6Q2, SPT No. 1 will be energized. Now station normal
supply is restored.
12. Close all the 11kV circuit breaker to restore the complete station Auxiliary power
supply.
13. Ensure availability of power supply to compressors at Switchyard before any further
operation of circuit breakers.
47
14. Reset 50V & 230V Battery Chargers at Switchyard and Power House and ensure that
load shifted from batteries to chargers.
15. Start 2nd Unit on 220kV side after ensuring that NO INDICATION PERSISTS in
Control Room.
16. Connect the 2nd Unit to 220kV Islamabad line, if so desired by NPCC by closing D4Q3
in case Unit No. 3 has been started. Make sure that 220kV circuit breaker D4Q2 & D4Q1
are open.
17. Close 220kV circuit breaker D4Q1 220kV, Bus Bar No.1 is energized now.
18. Close 220kV circuit breaker D5Q1, SPT-2 is energized now.
19. Ensure that 11kV station supply buses flank A and flank B are energized with TIE
circuit breaker open.
20. Open 220kV circuit breaker DQ2 of the first started unit. The first started unit is on
SNL with voltage built up, keep it running on SNL. Station supply will be available from
SPT-2.
21. Ensure that all 500kV circuit breakers are open except Bay 8.
22. Complete Bay 7 on 220kV side to energize 500kV Bus Bars 1&2. Now both 500kV
Bus Bars are energized.
23. For further restoration proceed as desired by NPCC.
48
10.5 PARALLEL OPERATION OF TRANSFORMERS IN THREE-PHASE
SYSTEMS
Transformers are in parallel operation if they are connected in parallel on at least two
sides or Parallel operation means direct terminal-to-terminal connection between
transformers in the same installations. A distinction should be made between bus bar
interconnection and network interconnection. Only two-winding transformers are
considered. The logic is also applicable to banks of three single-phase transformers.
The following four conditions must be satisfied in order to avoid dangerous transient
currents and for economical load sharing and successful parallel operation of two or
more transformers:
a) The same vector group (winding connections/phase-angle relation/clock-hour
number)
b) The same ratio with some tolerance and similar tapping range
c) The same percentage impedance voltage with some tolerance (± 10%) (same
relative short-circuit impedance
This also means that the variation of relative impedance across the tapping range
should be similar for the two transformers. When operating transformers in parallel,
their relative impedances will determine how they share the load. Transformers will
divide load in inverse proportion to their impedance (the transformer having less
impedance will tend to carry more load and vice versa). Note that the impedances of
two transformers should not be more than 10% apart for economical load sharing.
d) The same power rating
It is not advisable to combine transformers of widely different power rating (say, more
than 1:2). The natural relative impedance for optimal designs varies with the size of
the transformer. Rated power capacity ratio should be smaller than 3:1.
In practice, a mismatch of relative loading of no more than about 10 % between two
transformers of non-identical designs should be regarded as reasonable.
49
10.6 LOADING OF TRANSFORMERS – GUIDE FOR SHORT DURATION
EMERGENCY
AND
CYCLIC
OVER-LOADING
OF
POWER
TRANSFORMERS (REFERENCE IEC 60354 LOADING GUIDE FOR OILIMMERSED POWER TRANSFORMERS AND IEC60905 LOADING GUIDE
FOR DRY-TYPE POWER TRANSFORMERS) (THE SAME GUIDELINES
ARE ALSO RECOMMENDED AND ISSUED BY THE DESIGN T&G
DEPARTMENT VIDE # CED/NTDC/DSR/4675-84 DATED 17.20.2001)
During normal operation of a transformer, in addition to its rated power for continuous
loading, it can be temporarily over loaded within the permissible limits.
The bushings, tap changers and other auxiliary equipment shall not to restrict the
loading capabilities of the transformer.
The power transformers in WAPDA system generally conform to IEC-60076 which
can be overloaded to certain extent depending upon ambient air temperature and
previous average loading condition of the transformers. In this regard details are given
in IEC-60354 “Loading guide” for oil immersed transformers which may be gone
through for more knowledge on the subject. However, convenience the salient
points/instructions abstracted from the said IEC guide are given below for ready
reference and knowledge of operational staff for implementation:
1. In normal cyclic duty (once in every 24 hours) the transformers can be overloaded
up to 150% of its rated power in accordance with Table-1 to X. In these tables K1
indicates the average percentage load on transformer before over-loading. K2
indicates percentage load during the period of over loading and t indicates time in
hours.
2. These tables are based on ambient air temperature of 0ºC, 10ºC, 20ºC, 30ºC and
40ºC. For operation at 50ºC ambient air temperature special consideration has to be
made.
3. In emergency conditions (once in a few months) the transformer can be over loaded
for short duration to the extent given in Table-1 to X below, provided that the winding
hot spot temperature and top oil temperature do not exceed 140ºC and 115ºC
respectively. The figure of 115ºC for top oil temperature is tentative in actual practice
this value has to be limited to the temperature at which the conservator is completely
full of oil.
4. The transformer is expected to work for its normal life span if operated
continuously at a load such that winding hot spot temperature does not exceed 98 ºC.
50
For each 6 ºC rise in temperature above 98 ºC the transformer’s life is reduced to 50%.
It means that a transformer expected to give service for 30 years if operated at 98 ºC
winding temperature would run only for 15 years if operated continuously at 104 ºC.
5. As winding temperature and top oil temperature determine the effect of over
loading on determination of the insulation and the resultant reduction of transformer’s
life, utmost efforts should be made to keep the temperature gauges and the thermal
protective devices in proper working order.
TABLE –I
ONAN and ONAF Transformers Ambient Air Temperature = 0ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
>200
200
178
151
138
132
125
116
K1=50
>200
200
173
148
137
131
125
116
K1=70
>200
194
167
145
135
130
124
116
K1=80
200
138
163
143
134
129
124
116
K1=90
200
181
158
140
132
128
123
116
K1=100
193
172
152
136
130
126
122
116
TABLE –II
ONAN and ONAF Transformers Ambient Air Temperature = 10ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
>200
200
169
142
131
124
117
108
K1=50
>200
192
163
139
129
123
117
108
K1=70
>200
182
157
136
127
122
116
108
K1=80
199
176
152
133
125
121
116
108
K1=90
188
167
147
130
123
119
115
108
K1=100
173
154
137
124
119
115
112
108
51
TABLE –III
ONAN and ONAF Transformers Ambient Air Temperature = 20ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
>200
189
159
134
123
116
110
100
K1=50
>200
180
153
131
121
115
109
100
K1=70
193
170
146
127
118
113
108
100
K1=80
183
162
141
124
116
112
107
100
K1=90
169
150
132
118
112
109
105
100
K1=100
100
100
100
100
100
100
100
100
TABLE –IV
ONAN and ONAF Transformers Ambient Air Temperature = 30ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
>200
176
149
124
114
108
101
91
K1=50
192
168
142
121
111
106
100
91
K1=70
178
155
134
116
108
104
99
91
K1=80
164
145
126
111
104
101
97
91
K1=90
126
110
99
95
93
93
92
91
K1=100
-
52
TABLE –V
ONAN and ONAF Transformers Ambient Air Temperature = 40ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
190
164
137
115
104
98
92
82
K1=50
177
154
130
110
101
96
91
82
K1=70
158
137
118
103
96
92
88
82
K1=80
118
104
95
88
86
84
83
82
K1=90
-
K1=100
-
TABLE –VI
OFAF and ONWF Transformers Ambient Air Temperature = 0ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
177
163
147
133
127
123
119
114
K1=50
173
161
145
132
126
123
119
141
K1=70
168
155
142
131
126
122
119
114
K1=80
164
152
141
130
125
122
119
114
K1=90
160
149
138
129
124
122
118
114
K1=100
155
145
136
127
123
121
118
114
53
TABLE –VII
OFAF and ONWF Transformers Ambient Air Temperature = 10ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
170
157
141
127
121
117
113
107
K1=50
165
153
138
126
120
117
113
107
K1=70
160
148
136
124
119
116
112
107
K1=80
156
145
134
123
119
115
112
107
K1=90
152
142
131
122
118
115
112
107
K1=100
145
135
126
119
115
113
110
107
TABLE –VIII
OFAF and ONWF Transformers Ambient Air Temperature = 20ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
161
148
133
119
113
110
106
100
K1=50
157
144
130
118
112
109
105
100
K1=70
151
139
127
116
111
108
105
100
K1=80
146
136
125
115
110
108
105
100
K1=90
141
131
121
113
109
106
104
100
K1=100
100
100
100
100
100
100
100
100
54
TABLE –IX
OFAF and ONWF Transformers Ambient Air Temperature = 30ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
153
140
125
113
107
103
99
92
K1=50
149
136
123
111
106
102
98
92
K1=70
142
131
119
109
104
101
98
92
K1=80
136
126
116
107
103
100
97
92
K1=90
120
111
104
99
96
95
94
92
K1=100
-
TABLE –X
OFAF and ONWF Transformers Ambient Air Temperature = 40ºC
Values of K2 for given values on K1 and t
t=0.5
t=1
t=2
t=4
t=6
t=8
t=12
t=24
K1=25
144
131
117
105
98
95
91
84
K1=50
139
127
114
103
97
94
90
84
K1=70
131
120
110
100
95
93
89
84
K1=80
119
109
100
94
90
89
86
84
K1=90
-
K1=100
-
55