1

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

4

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

7

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

9

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.

10

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

11

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…