Power Transformer Repair (Cap: 1.2 Nos/Day)

POWER TRANSFORMER REPAIR (CAP: 1.2 NOS/DAY)

[EIRI/EDPR/4504] J.C.: 2720XL

A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is called inductive.

If a load is connected to the secondary, current will flow in the secondary winding, and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in the secondary winding (Vs) is in proportion to the primary voltage (Vp) and is given by the ratio of the number of turns in the secondary (Ns) to the number of turns in the primary (Np) as follows:

By appropriate selection of the ratio of turns, a transformer thus enables an alternating current (AC) voltage to be "stepped up" by making Ns greater than Np, or "stepped down" by making Ns less than Np. The windings are coils wound around a ferromagnetic core, air-core transformers being a notable exception.

COST ESTIMATION

Plant Capacity            1.2 Nos/Day  

Land & Building (4000 sq.mt.)    Rs. 24.60 Lac    

Plant & Machinery                    Rs. 21.00 Lac 

Working Capital for 0.25 Months    Rs. 1.21 Lac 

Total Capital Investment          Rs. 50.69 Lac 

Rate of Return                          11%

Break Even Point                      80%

CONTENTS

INTRODUCTION

PRINCIPLE OF TRANSFORMER

FIGURE 1: RELATIONSHIP BETWEEN CURRENT, MAGNETIC FIELD STRENGTH AND FLUX

FIGURE 2: TRANSFORMER SCHEMATIC

POWER TRANSFORMER

1. THREE PHASE TRANSFORMERS:-

DRY TYPE CAST RESIN TRANSFORMERS USING UNFILLED SYSTEM:-

DETAILS OF POWER TRANSFORMER

CONSTRUCTION

CORE

YOKE SECTIONS

WINDINGS

LOW VOLTAGE WINDING

HIGH VOLTAGE WINDING

COOLING TUBES

OIL TANK

CONSERVATOR

BREATHER

BUSHING INSULATORS:-

BUCHHOLZ RELAY

OIL GAUGE

RELIEF AND EXPLOSIVE VENTS

TAPPING SWITCHES

CHARACTERISTICS OF TRANSFORMER OIL

CHARACTERISTICS

CONSTRUCTION OF TRANSFORMER

(A) OUTER PARTS OF TRANSFORMER

(1) YOKE

(2) BUCHHOLZ RELAY

(3) CONSERVATOR TANK

(4) OIL LEVEL INDICATOR

(5) BREATHER

(6) WINDING TEMPERATURE INDICATOR

(7) COOLING FANS/RADIATOR

(8) SYSTEM GROUND TERMINAL

(9) DRAIN VALVE

(B) INNER PARTS OF TRANSFORMER

(1) CORE

(2) PRIMARY WINDING (HV-WINDING)

(3) SECONDARY WINDING (LV-WINDING)

(4) TRANSFORMER OIL

B.I.S. SPECIFICATION

TESTING OF TRANSFORMER

1. INSULATION RESISTANCE TEST

TEST PURPOSE

TEST INSTRUMENTS

TEST PROCEDURE

2. DC RESISTANCE OR WINDING RESISTANCE TEST

TEST PURPOSE

TEST INSTRUMENT

METHOD NO: 1 (KELVIN BRIDGE METHOD FOR MEASUREMENT

OF WINDING RESISTANCE)

TEST PROCEDURE

KELVIN BRIDGE

METHOD NO: 2 (CURRENT VOLTAGE METHOD OF MEASUREMENT

OF WINDING RESISTANCE)

DC WINDING RESISTANCE TEST (CURRENT-VOLT METHOD)

TEST PROCEDURE

REQUIRED PRECAUTION

TEST ACCEPTANCE CRITERIA

TEST CAN DETECT

3. TURNS RATIO/VOLTAGE RATIO TEST

TEST PURPOSE

TEST INSTRUMENTS

METHOD NO 1 TURNS RATIO TESTING

TEST PROCEDURE

TRANSFORMER TURNS RATIO METER (TTR)

BRIDGE CIRCUIT

TEST CAUTION

METHOD NO 2 VOLTAGE RATIO TESTING

TEST PROCEDURE

TEST ACCEPTANCE CRITERIA

TEST CAN DETECT

TEST INSTRUMENT

TEST PROCEDURE

SHORT CIRCUIT TEST (WITHOUT CT)

SHORT CIRCUIT TEST (WITH CT)

ACCEPTANCE CRITERIA

TEST CAN DETECT

6. OPEN CIRCUIT / NO LOAD TEST

TEST PURPOSE

TEST INSTRUMENTS

TEST PROCEDURE

TEST CAUTION

ACCEPTANCE CRITERIA

7. CONTINUITY TEST

PURPOSE OF TEST

TEST INSTRUMENTS

TEST PROCEDURE

TEST CAN DETECT

8. MAGNETIC CURRENT TEST

TEST PURPOSE

MAGNETIC CURRENT TEST

TEST PROCEDURE

9. MAGNETIC BALANCE TEST

TEST PURPOSE

TEST INSTRUMENT

TEST CIRCUIT DIAGRAM

MAGNETIC BALANCE TEST

TEST PROCEDURE

10. HIGH VOLTAGE TESTS ON HV & LV WINDING

PURPOSE

TEST INSTRUMENT

TEST CIRCUIT DIAGRAM

HV HIGH VOLTAGE TEST

LV HIGH VOLTAGE TEST

TEST PROCEDURE

11. DIELECTRICAL TEST

TEST PURPOSE

TEST INSTRUMENTS

TEST PROCEDURE

METHOD NO 1 (SEPARATE SOURCE VOLTAGE WITHSTAND TEST)

DIELECTRIC TEST (SEPERATE VOLTAGE SOURCE WITHSTAND TEST)

METHOD NO 2 (INDUCED SOURCE VOLTAGE WITHSTAND TEST)

ACCEPTANCE CRITERIA

DIELECTRIC TEST (INDUCED VOLTAGE TEST)

ACCEPTANCE CRITERIA

METHOD NO 3 LIGHTING IMPULSE TEST

12. TEMPERATURE RISE TEST OF TRANSFORMER

MARKET OVERVIEW OF POWER TRANSFORMER

PRODUCT INSIGHTS

REGIONAL INSIGHTS

COMPETITIVE INSIGHTS

POWER TRANSFORMERS MARKET TO RIDE ON INCREASING GLOBAL

ENERGY DEMAND TO REACH US$28.69 BILLION BY 2019

GLOBAL POWER TRANSFORMERS MARKET GROWING

TRANSFORMER REPAIR PROCESS

DRYING

ELECTRIC TEST

METHOD OF REPAIRING TRANSFORMER

REPAIR METHOD AND ORDER OF REPAIR PARTS OF POWER

TRANSFORMER

LIFTING OF COMPONENTS

REPAIR

DRYING OF THE TRANSFORMER

COMBINED LFH- AND HOT OIL SPRAY/VACUUM DRYING PROCESS TECHNOLOGY

TEMPERATURES

DRYING TIME

TESTING

THE MOBILE HIGH VOLTAGE TEST FIELD USED FOR INDUCED

VOLTAGE TEST

THE MOBILE HIGH VOLTAGE TEST FIELD USED FOR APPLIED

VOLTAGE TEST

MOBILE HIGH VOLTAGE TEST FIELD USED FOR MEASUREMENT

OF NO LOAD AND ON LOAD LOSSES

IMPULSE VOLTAGE SYSTEM

POWER TRANSFORMER INSTALLATION, ACCEPTANCE

AND MAINTENANCE PROCEDURE

UNSCHEDULED TRANSFORMER MAINTENANCE

TRANSFORMER ORDINARY MAINTENANCE

PROTECTIVE MAINTENANCE

DRY-TYPE POWER TRANSFORMERS

INSTALLATION

TABLE 1. MAXIMUM 24H AVERAGE COOLING AIR TEMPERATURE (°C)

TRANSFORMER INSPECTION

TRANSFORMER ACCEPTANCE TESTS

TABLE 2. DRY-TYPE TRANSFORMER IR FIGURES

TABLE 3. DIELECTRIC TEST VALUE FOR ACCEPTANCE AND PERIODIC MAINTENANCE OF DRY-TYPE POWER TRANSFORMERS

MAINTENANCE

DRYING-OUT TECHNIQUES

STORAGE

LIQUID-TYPE POWER TRANSFORMER

INSTALLATION

INSPECTION

POWER TRANSFORMER ACCEPTANCE TESTS

TABLE 4. LIQUID-FILLED TRANSFORMER IR FIGURES

TRANSFORMER MAINTENANCE

TABLE 5. TRANSFORMER INSPECTION AND MAINTENANCE PLAN

DRYING-OUT TECHNIQUES

TRANSFORMER STORAGE

POWER TRANSFORMER DIAGNOSTIC GUIDE

TABLE 6. CAUSES OF TRANSFORMER DAMAGE

TESTING DETAILS FOR POWER TRANSFORMER

TESTING

LOAD LOSSES

IMPEANCE VOLTAGE MEASUREMENT

MEASURE OF WINDING RESISTANCE

MEASUREMENT OF INSULATION RESISTANCE

HIGH VOLTAGE TEST

INTER -TURN INSULATION TEST

SUPPLIERS OF RAW MATERIALS

SUPPLIERS OF HOT ROLLED SHEETS

SUPPLIERS OF M.S CHANNELS AND ANGLES

SUPPLIERS OF M.S. FLAT

SUPPLIERS OF M.S. PLATE

SUPPLIERS OF M.S. PIPE

SUPPLIERS OF CARGO LAMINATION

SUPPLIERS OF DPC COPPER WIDING WIRE

SUPPLIERS OF TRANSFORMER OIL

SUPPLIERS OF CRAFT PAPER

SUPPLIERS OF M.S BOLTS AND NUTS

SUPPLIERS OF TRANSFORMER BUSHINGS

SUPPLIERS OF PAINT

SUPPLIERS OF PLANT AND MACHINERIES

SUPPLIERS OF TRANSFORMER COIL WINDING MACHINE

SUPPLIERS OF OIL FILTER MACHINE

SUPPLIERS OF VACCUME IMPREGNATION PLANT

SUPPLIERS OF ELECTRICAL MEASURING INSTRUMENT

SUPPLIERS OF TRANSFORMER OIL TESTING KIT

SUPPLIERS OF BENCH GRINDER

SUPPLIERS OF DRILLING MACHINE

SUPPLIERS OF SHEARING MACHINE

SUPPLIERS OF WELDING MACHINE

SUPPLIERS OF AIR COMPRESSORS

SUPPLIERS OF MATERIAL HANDLING EQUIPMENTS

SUPPLIERS OF PAINTING EQUIPMENTS

SUPPLIERS OF FIRE FIGHTING EQUIPMENTS

SUPPLIERS OF EOT CRANE

SUPPLIERS OF AIR POLLUTION CONTROL EQUIPMENTS

SUPPLIERS OF PLATEFARM WEIGHING MACHINE

SUPPLIERS OF SHOT BLASTING MACHINE

APPENDIX – A:

01. PLANT ECONOMICS

02. LAND & BUILDING

03. PLANT AND MACHINERY

04. OTHER FIXED ASSESTS

05. FIXED CAPITAL

06. RAW MATERIAL

07. SALARY AND WAGES

08. UTILITIES AND OVERHEADS

09. TOTAL WORKING CAPITAL

10. TOTAL CAPITAL INVESTMENT

11. COST OF PRODUCTION

12. TURN OVER/ANNUM

13. BREAK EVEN POINT

14. RESOURCES FOR FINANCE

15. INSTALMENT PAYABLE IN 5 YEARS

16. DEPRECIATION CHART FOR 5 YEARS

17. PROFIT ANALYSIS FOR 5 YEARS

18. PROJECTED BALANCE SHEET FOR (5 YEARS)