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Power Quality Improvement of Incoming Supply (TNEB)
Steps planned to Improve Power Quality:
1. Install HT AVR to ensure Voltage variation within ±1%.
2. Install UPS to reduce losses due to Power Brown outs & Black
outs (M/c Breakdown, Tool Breakdown etc.).
3. Upgrade the Voltage from 11KV to 33KV.
Steps Planned to Improve Power Quality
• Failure of Motor windings in Heat Treatment Machines due to Low voltage (VHF, SQF etc.,). • Imported CNC,PLC M/c’s fails to run without coolant pump due to voltage fluctuation.
• lights are flickering and capacitors burst due to low voltage.
• Frequent tripping of Circuit breakers due to low voltage during full load.
• Frequent tripping of Air conditioner and compressors due to voltage fluctuation.
Problems occurred before installing AVR
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AVR Installation
BeforeAfter
Incoming supply (TNEB)VCB
2
Bus bar
Tr-1 Tr-2 Tr-3 Tr-4
Load LoadLoadLoad
Tr-1 Tr-2 Tr-3 Tr-4
Load LoadLoadLoad
Bus barVCB 2
VCB 1
Incoming supply (TNEB)
6.3 MVA AVR
Additionally Inserted
5
AVR system installed
Voltage stabilization process in LT side
Input voltage to AVR : 9000V to 12000VOutput voltage from AVR : 11000V ± 1% (10890V to 11110V)
Stabilization process : HT voltage LT voltage
conventional : 9000V to 12000V 340V to 470V
Recommended : 11000V±1% 415V±6% (i.e.390V
to 440V)
By AVR : 11000V±1% 410V to 420V
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voltage bandwidth for motors
D
GOOD
ALLOWED
DANGEROUS
410V
420V
390V
440V
340V
470V
Voltage Bandwidth
Voltage in LT before & after installation of AVRVoltage in LT side
050
100150200250300350400450500
Time
Volta
ge
Before After Required
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After installation of AVRAvoided M/c brownouts, blackouts due to voltage
variation.
Avoided failure of Motor winding and CNC M/c down time due
to voltage fluctuation.
Avoided failure of lights and fans due to low voltage.
Avoided tripping of Air conditioner and compressors due to under voltage.
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Up gradation of voltage from 11 KV to 33 KV
6.3 MVA AVR
33 KV TNEB SUPPLY
RMG 33 KV VCB
6.3 MVA,33KV / 11KV TRANSFORMER
11 KV VCB
VCB
VCB VCB VCB
To Power House To
DI building To E & D
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Increasing the Capacity of UPS
Bus bar
Tr-1 Tr-2 Tr-3 Tr-4
Load LoadLoad
160 KVA
Existing
160 KVA 550 KVA 160 KVA
Load
Existing CapacityRotary = 870 KVAUPCR = 160 KVA
Planned CapacityRotary = 2360KVAUPCR = 320 KVA
Thank You…