BATTERY
Capacity
of battery is denoted by Amp/hour. = Capacity x hour
V-Eb
Cell
current (I) =--------
R + r
Where
V= Emf, Eb = Bach emf, R= outside resistance, r= Internal resistance
Battery
charging current = Capacity/hours. *cell charging current should be applied as
per manual.
Equalizing
Charging: Charge on low rate. Charge up to three same reading of voltage &
sp. Gravity.
Battery
drawback:
Sulfation: Active material in the form of sulfur,
deposits on +ve & -ve plate and surface of plate is hardened.
Plates
buckling: At the time of charging/discharging if it is taking high current then
its temperature will also increase. Due to this, plates get bending
un-uniformly and there is a possibility of short ckt.
Sensitization:
In battery, active material is depositing on the plates. An active material, in
the form of powder form deposited at the bottom of cell. So internal resistance
of the cell increases and battery loose its capacity.
Ni
– Ca Battery Chemical Reaction
+ve
Plate: Nickel hydroxide as the active constituent.
-ve
Plate: Cadmium hydroxide
Electrolyte:
Solution of Potassium hydroxide in DM water with lithium hydroxide as an
additive.
2Ni(OH)3
+ 2Cd(KOH) -> 2Ni(OH)2 +
2Cd(OH)2 + 2KOH
The
Potassium hydroxide electrolyte takes no parts in these reactions and acts only
as a carrier of ions and the lithium hydroxide additive in the electrolyte
significantly increases the life of the cell since it has a beneficial effect
on the positive electrodes. This beneficial effect is more.
UPS
A BATTERY: 350A/h (a) C-10 (T350P) 2V per cell, 180 cells.
UPS
B BATTERY: 200 A/h (a) C-10, 12v, 32 CELLS
CABELING
REQUIREMENTS
Planning
cable runs
·
Use the shortest possible motor cable lengths.
·
Use a single length of cable to a star junction point to feed
multiple motors.
·
Keep electrically noisy and sensitive cables apart.
·
Keep electrically noisy and sensitive parallel cable runs to
a minimum. Separate parallel cable runs by at least 0.25 metres. For runs
longer than 10 metres, separation should be increased proportionally. For
example if the parallel runs were 50m, then the separation would be
(50/10)x0.25m.
·
Sensitive cables should cross noisycabes a 900 .
·
Never run sensitive cables close or parallel to the motor, dc
link and braking chopper circuit for any distance.
·
Never run supply, dc link or motor cables in the same bundle
as the single/control and feedback cables, even if they are screened.
·
Ensure EMC filter input and output cables are separately
routed and do not couple across the filter.
INCREASING
MOTOR CABLE LENGTH
Because cable capacitance and hence
conducted emission increase with motor cable length, conformance to EMC limits
is only guaranteed with the specified ac supply filter option using a maximum
cable length as specified .
This maximum cable length can be
improved using he specified external input or output filters.
Screened/armored cable has
significant capacitance between the conductors and screen which increases
linearly with cable length (typically 200pF/m but varies with cable type and
current rating).
LONG CABLE
LENGTHS MAY HAVE THE FOLLOWING UNDESIRABLE EFFECTS;
Ø Tripping on ‘Over current’
as the cable capacitance is charged and discharged at the switching frequency.
Ø Producing increased
conducted emissions which degrade the performance of the EMC filter due to
saturation.
Ø Causing RCDs (Residual
Current Devices) to trip due to increased high frequency earth current.
Ø Producing increased
heating inside the EMC ac supply filter from the increased conducted emissions.
These effects can be
overcome by adding chokes or output filters at the output of the VSD.
STAR POINT EARTHING:
A star-point earthing
policy separates ‘noisy’ and ‘clean’ earths. Four separate earth bus bars
(three are insulated from the mounting panel) connect to a single earth point
(star point) near the incoming safety earth from the main supply. Flexible,
large cross-section cable is used to ensure low HF impedance. Bus bars are
arranged so that connection to the single earth point is as short as possible.
XLPE( CROSS LINGK POLLY ETHYLENE)
ADVANTAGE
1. Conductor operating
temperature : 900C
2. Short ckt withstand
temperature :2500C
3. High current rating
4. High di-electric strength
5. Very low di-electric
losses
6. Due to high di-electric
strength, size is less compared to other.
7. Low weight, easy for
laying, easy bending ie. 200.
8. Low water absorption.
9. Low charging current
10. Easy jointing procedure
11. Fire retardant
COMPARISION
BETWEEN XLPE AND PILCA
|
SN
|
XLPE
|
PILC
|
|
1
|
On load
900 C Temperature
|
On load
700 C temperature
|
|
2
|
Low
weight
|
Heavy
weight
|
|
3
|
Defuses
moisture
|
Absorbs
moisture
|
|
4
|
Short
circuit temperature 2500C
|
Short
circuit temperature is 1600C
|
|
5
|
Fire
resistance - Fair
|
Fire
resistance - poor
|
CABLE CODE:
1. Copper conductor --
2. Aluminum conductor A
3. PVC sheath &
insulation Y
4. Steel round wire armor W
5. Steel strip armor F
6. Steel double round wire
armor WW
7. Steel double strip armor FF
GENERAL TECHNICAL DATAS FOR 33KV(E) 400 sq mm XLPE CABLE
|
SN
|
DETAILS
|
Data
|
|
1
|
Name of manufacturer & address of work
|
Polycab wires Pvt. Ltd, HICCL, 1st fl,
731, Pandit Satwalkar marg, Mahim, Mumbai-400016
|
|
2
|
Applicable standard
|
IS:7-98(para II)1985 with latest amendments.
|
|
3
|
Voltage grade
|
33KV(E)
|
|
4
|
Conductor temperature at rated current
|
900C
|
|
5
|
Max. temperature during short circuit under hot
condition
|
2500C
|
|
6
|
No. of cores
|
3
|
|
7
|
Cross section area of conductor
|
400 sq mm
|
|
8
|
Conductor material, hardness & conductor
flexibility class
|
Aluminum H2/H4 grade, class II IS:8130/84
|
|
9
|
No. & diameter of conductor stands
|
57 strands, 3.06 dia
|
|
10
|
Shape of conductor
|
Compact, circular
|
|
11
|
Material & min. thickness of conductor screening
|
Extruded semi conducting compound of 0.30 mm
thickness
|
|
12
|
Insulation material composition
|
Extruded XLPE
|
|
13
|
Min. & normal thickness of insulation
|
7.82mm (minimum)
|
|
14
|
Max. electric stress on the conductor screen
|
30 – 35 KV/mm
|
|
15
|
Material, min. thickness type of non-metallic
insulation screening
|
Free strippable with stripper extruded, semi
conductor compound of 0.30 mm thickness.
|
|
16
|
Material, min. thickness & width of metallic
screen
|
Copper type 30 x 0.05 mm
|
|
17
|
Filler material
|
Suitable PVC compound
|
|
18
|
Min, thickness & material of inner sheath
|
0.70 mm, extruded PVC compound type ST-2
|
COMPARISION BETWEEN XLPE, PVC, PILC
|
SN
|
DATA
|
XLPE
|
PVC
|
PLIC
|
|
1
|
Specific Gravity
|
0.93
|
1.35,1.46
|
1.1
|
|
2
|
Electric loss factor(Temp. 200C)
|
0.0004
|
0.07
|
0.003
|
|
3
|
Volume resisting area 200C Aluminum &
Copper
|
1117
|
1010-1015
|
1015
|
|
4
|
Max permissible operating continue temperature
|
900C
|
700C
|
650C
|
|
5
|
Max permissible short circuit temperature
|
2500C
|
1600C
|
1600C
|
|
6
|
Short time O/L temperature
|
1300C
|
1200C
|
800C
|
|
7
|
Dielectric constant at 200C
|
2.35
|
6-8
|
3-5
|
|
8
|
Power Factor at max. conducting temperature
|
0.008
|
0.1
|
0.01
|
|
9
|
Impulse level volts/min
|
2000
|
1100
|
1800
|
|
10
|
Thermal resistivity
0C/Con/Watt
|
350
|
650
|
550
|
|
11
|
Partical discharge picl con/m3
|
5
|
40
|
--
|
If = Ish/√t Where It – Short ckt rating for 1
sec
t
– directional in sec
Ish – Short ckt ratio for 1 sec
CLASSIFICATION OF POWER SUPPLY
1. Class IV - Normal PS
415V 3 ph – 2500 KVA
2. Class III – Diesel Generator setm 415V, 3 ph, 1010KVA – Self exited.
3. Class II - UPS – 230V, 50 KVA
4. Class I - Battery pS – 110VDC,
550AH & 425 AH-ROP S/stn, 300 AH – PREFRE S/stn.
Class I – Control ckt VCB, Exit
lighting
Class II – Control room all area
monitors, SCADA, trx scanners.
Class III – E2 fans & lighting
Class IV – All are normal supply.
FRLS: Flame Retardant Low Smoke Cable: Used in High block
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