Project Presentation

DESIGN OF EHV SUBSTATION AT FACT UDC

Done by : Arunkumar M.P

Bijesh K.B Jijo Francis

Lipin A.K

ABOUT

FACT is a doyen among the manufactures in India. It started production in 1944 on the bank of river Periyar. It was then the first large scale fertilizer factory in the entire country. FACT has three manufacturing divisions, two divisions at Udyogamandal and one at Ambalamedu. The overall production capacity of the company is in the range of 2.58 lakhs of phosphates ad 50,000 tones of caprolactum.

FACT has also successfully branched out to the field of chemical and

fertilizer technology and design capabilities research , development and fabrication engineering services. FACT engineering and design organization (FEDO) and FACT engineering works (FEW) are well known names today not only in India but also outside countries.

FACT has also successfully branched out to the field of chemical and fertilizer

technology and design capabilities research , development and fabrication engineering services. FACT engineering and design organization (FEDO) and FACT engineering works (FEW) are well known names today not only in India but also outside countries.

FACT Udyogamandal division is the oldest in FACT with an installed capacity of 450TPD of ammonium phosphate and 680TPD of ammonium sulphate fertilizers.

Besides power received from KSEB, it is also generated in both Udyogamandal and Ambalamedu complexes ; In Udyogamandal two turbo generators of 6MW and 16MW capacities are available for power generation. KSEB power is received at Udyogamandal from Kalamassery 220KV substation.

LIST OF CONTENTS

INTRODUCTIONSINGLE LINE DIAGRAM SYSTEM COMPONENTS FAULT LEVEL CALCULATION EARTHING SYSTEM EARTH GRID CALCULATIONDESIGNREFERENCES

INTRODUCTION

SUBSTATION :

Defined as : An Assembly of apparatus which transforms the characteristics of Electrical Energy from one form to another.

For economical transmission and distribution, higher voltage should be used.

Consumers do not use very high voltages.

So they must be transformed into low voltages by means of transformers in sub-stations.

Thus, a substation may be called as link between the generating stations and consumers.

The distribution voltages generally used in practice are 66KV, 11KV and 33KV. But in this project work, we are considering 110KV sub station.

SINGLE LINE DIAGRAM

FAULT LEVEL CALCULATION

Kalamassery fault level = 3600 MVA2.5% future expansion = 4500 MVA10% voltage Regulation = 5445 MVABase MVA = 100 MVASource Impedance = Base MVA x100 Fault level MVA

= 100x100 = 1.8365 5445Length of ACSR = 5.1 KmOhmic impedance of the calculator = 0.292+0.5772

= 0.0841+0.332929

= 0.6458/Km = 0.6458x5.1 = 3.29Ω% Z = KVA x Z = 3.29x100x1000 = 2.72% 10 x KV2 10x1102

% impedance of 110 KV bus at UDL = 1.8365+2.72 = 4.5565Fault level = 100x100 = 2194.67MVA 4.5565 Fault current = 2194.6 = 11.53 KA 3x110% Impedence of 20 MVA Transformer = 15.6%% Impedence of 100 MVA base = 100x15.6 = 78 20

% Impedence of 11KV side of Transformer = 78 + 4.5565

= 82.5565Fault level of 11Kv side of Transformer = 100 x100 = 121.13 MVA

82.5565

Fault current = 121.13 / 3x11 = 6.365 KA

DESIGN OF SUBSTATION

Earth Resistively 4 spike method Earth Resistance 10m distance - 0.03 Ω

5m distance - 0.45 Ω Earth pit - 0.31Ω

P,C, R shorted and is connected to the earth

pit. P2 & C2 are connected to the two terminals which are connected to the 2 electrodes which are at 20m distances.

SITE SELECTION

Main points to be considered while selecting the site for EHV Sub-Station are as follows:i) The site chosen should be as near to the load center as possible.ii) It should be easily approachable by road or rail for transportation of equipments.iii) Land should be fairly leveled to minimize development cost.iv) Source of water should be as near to the site as possible. This is because water is requiredfor various construction activities; (especially civil works, earthing and for drinking purposes etc.)v) The sub-station site should be as near to the town but should be clear of public places, aerodromes and Military / police installations.

vi) The land should be have sufficient ground area to accommodate substation equipments,

buildings, staff quarters, space for storage of material, such as store yards and store sheds. with roads and space for future expansion.vii) Set back distances from various roads such as National Highways, State Highways should be observed as per the regulations in force.viii) While selecting the land for the substation preference to be given to the Govt. land over private land.ix) The land should not have water logging problem.x) The site should permit easy and safe approach to outlets for EHV lines.

RESISTIVITY

r= 40x3.14x0.03 = 40x3.14x0.03 = 20.93 1.89 - 0.71 0.18

EARTH GRID AREA CALCULATIONS

Ac2 = If (tc.Tr.Sr.x104/TCAP)/ln(1+(TmTo)(Ko+To))Where, If = Fault current = 25980A

Tc = Fault current duration = 1SecAr = Efficient if thermal expansion = 0.00423Sr = Soil resistively = 20.93 Ω m

TCAP = Thermal capacity /unit volume in J/cm3 0C = SHxSWx4.184 = 4.184x0.114x07.8

= 3.749Where, SH = Specific heat SW = Specific weightAt 4500C, Tm = Maximum allowable temp in 0c = 6200C

To = Ambient Temp in 0C =500C

KO = (1-Tr) = 216.64 TrTr = reference temperature for material constant = 20 0C

Earth grid area , Ac2= 25.980 (1x0.00423x104x20.93/3.749)/

ln(1+(620-50)/(216+50))= 533501.28m2

AC = 730:41m2

By including earth satellite earth mat the area of the earth grid can be increased to 075 m2 (35x25)

DESIGNConductor size :

Ondor clonk’s formula provides a reasonable method to compute the area of iron section for earthing.

A =I t : (74/10g10 (1+(Tm-To)/(234+To)x10-3)Where , A = Area of iron section in m2

I = rms current in amps Tm = Max allowable temp in 0C To = Ambient Temperature in 0CMax allowable temp for steel in 620oc for welded joint and 3100C for bolted joints.

The formula is simplified as : A=KI t

Initial designAssume a preliminary layout of 21mx18m grid with equally spied conductors and shown in figure with spacing D=15m grid burial depth h=0.75m

Grounding mat design :Considering further expansion fault current for the design procedure as 259804. For grounding mat and welded joint are to be provided.

Area of cross section = A=K I t = 0.0122-259801 = 317m2

Area of 40mm dia. rod = 40x317 = 1257m2

Hence area of cross section is sufficient earth matis designed at a normal spacing of 15m b/w conductors. As per initial design length of earth grid including down rods = 36220mNo: of lowers is assumed as 3 and lower foot resistance as : 10 ΩResistance of 3 lowers =10/3 = 3.33 ΩTotal resistance of line = Resistance of lower + Resistance of ground wire

Resistance of ground wire :

Resistance of ground wire is assumed as : 3 ΩTotal resistance of one line = 3.33 +3 = 6.33 ΩTotal resistance of two lines together = 6.33/2

= 3.165 Ω The resistance of the earth grid may be calculated as

R=(s/4r) +(s/l)S = 20.93 ΩmR = Radius of the equivalent surface of the grid

= (area of yard /3.14) = 875/3.14 = 16.68mR = (20.93/4x16.68+20.93/36220) = 0.31 ΩValue of electrode resistance = 1/((1/0.31)+1/3.165)

= 0.28

For fault current of 25980 A in 110Kv bas grid ground return current = 0.357x0.28x11530 = 1152.54A

Minimum length of ground conductor required :L=Km x Ki x gt/(116+0.174xCsxSs)Where,

K = 1/2 [ ln ([D2 / 16 h.d] + [(D+2.h)/ 8Dd]2 –[h / 4d] +[Kit/Kh] x ln(8/ (2n-1))]

D = spacing of conductor = 15md = diameter of conductor = 0.04mH= depth of buried conductor = 0.75mN= 14x1q=16

BUS BAR

Used to interconnect the loads and sources of electrical power It connects incoming and outgoing transmission linesAlso connect generator and main transformer in power plantMaterial used: Copper or Aluminium Size of bus bar to determine max. amount of current passed

POWER TRANSFORMERS :

A transformer is a static device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the 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 voltage in the secondary winding. This effect is called mutual induction.

Power transformers are usually the largest single item in a substation. Due to large quantity of oil, it is essential to take precaution against the spread of fire.

TRANSFORMER No.4

Make TELK-TRANDORMER WITH ON LOAD TAP CHANGER

Transformer Specification Ref.No.IS 2026-1977

Maker’s Sl No. 120270-2

Type SALOCR

Form 3NYCP

Year of Manufacture 1988

Rated KVA HV 12500/20000

LV 12500/20000

Volts – no load HV 110000V

HV 65.7/105.1

Amperes LV 657/1051

ONAN/ONAF

Type of cooling 15.60%

Impedance voltage (20MVA base) HV/LV HV 3

Phase LV 3

50Hz

Frequency C/S YNyno

Vector Symbol 24000Kg

Transportation Mass 20000Kg

Un-tanking Mass 9495 Kg

Total of oil 41000Kg

Oil Liters 10550 Litres

Air Circulation 8x90 m3/min

POSITION HV CONNECTION HV VOLTS HV CURRENT

1 1N-15 116600 99.2

2 1N-14 114950 110.6

3 1N-13 113300 102

4 1N-12 11650 103.5

5 1N-11 110000 105.1

6 1N-10 108350 106.1

7 1N-9 106700 108.4

8 1N-8 105050 110.1

9 1N-7 103400 111.8

10 1N-6 101750 113.6

11 1N-5 100100 115.5

12 1N-4 98450 117.4

13 1N-3 96800 119.4

CIRCUIT BREAKERS

A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit.

Its function is to interrupt continuity, to immediately discontinue electrical flow.

SF6 CIRCUIT BREAKERS

The SF6 is an electro-negative gas and has a strong tendency to absorb free electrons. The contacts of the breaker are opened in a high pressure flow of SF6 gas and an arc is struck between them. The conducting free electrons in the arc are rapidly captured by the gas to form relatively immobile negative ions.

This loss of conducting electrons in the arc quickly builds up enough insulation strength to extinguish the arc.

FEEDER CIRCUIT BREAKER

Make Crompton greaves everyday solutions

Type GAS CIRCUIT BREAKER 120-SFM-32B

Year of Manufacture 2006

Rated voltage 145Kv

Rated Frequency 50Hz

Rated Normal Current 3150 A

Rated making capacity 100 KAP

Rated short circuit breaking capacity 40 Ka

Rated short time current 40Ka for 3 seconds

Rated lightening impulse withstand voltage 650 KVP

First pole to clear factor 1.5

Rated opr.Seq. 0-0.3sec-CO-3 Min-CO

Rated Gas pressure 7Kg/Cm2-g(at200c)

Gas Wt 8 Kg

Total Weight 1550 Kg

Closing 110V DC, Tripping 110V DC

230V AC

If, 230V AC

TRANSFORMER CIRCUIT BREAKERS

Make Crompton greaves Nasik, INDIA

Type GAS CIRCUIT BREAKER 120-SFM-32B

Year of Manufacture 1990

Rated voltage 145Kv

Rated Frequency 50Hz

Rated Normal Current 31.50 A

Rated making capacity

Rated short circuit breaking capacity 31.50 KA

Rated short time current 31.5 Ka for 3 seconds

Rated lightening impulse withstand voltage 650 KVP

First pole to clear factor 1.5

Rated opr.Seq. 0-0.3sec-CO-3 Min-CO

Rated Gas pressure 7Kg/Cm2-g(at200c)

Gas Wt 9 Kg

11.) ISOLATORS

These are essentially off load devices although they arecapable of dealing with small charging currents ofBus bars and connections. The design of isolators is closely related to the design ofsubstations. Isolator design is considered in the followingaspects:

• Space Factor• Insulation Security• Standardization• Ease of Maintenance• Cost

Some types of isolators include:• Horizontal Isolation types• Vertical Isolation types• Moving Bushing types

FEEDER ISOLATORS WITH EARTH SWITCH

Make G power switch gear ltd, jeedimetla, hydrabad, 500055

Type DB

KV Rating 123

Current Rating 1600A

Year of Manufacture 2005

Impulse Voltage 550Kv peak

Short time current for 1 sec 26.24 Ka rms

Operating Mechanism Motor

Control voltage 110V DC

What exactly does a Lightning Arrestor Do?

It Does not Absorb the Lightning

It Does not Stop the Lightning

It Does Divert the Lightning to Ground

It Does Clamp (limit) the Voltage produced by the Lightning

It Only protects equipment electrically in parallel with it.

LIGHTENING ARRESTOR

Name of the manufacturer OBLUM ELECTRICAL INDUSTRIES PVT LTD

Trade mark Oblum

Type of identification Metovar

Rated voltage 96Kv

Continuous operating voltage 81Kv (RMS)max

Rated frequency 50Hz

Nominal discharge current 10Ka

Long duration discharge class 3

Pressure relief class ‘A’

CURRENT TRANSFORMER

The current transformer is used to measure the very high current passing through the bus.

It step downs the current and measurements are taken in the control room the ratings of CT is based on the ampere.

These CTs are connected to the control room through cables.

FEEDER CURRENT TRANSFORMER -1 (FCT-1)

Ring winding current transformers

Make Brown Boveri-Stromeandler

Type TMRg 110

Year of Manufacture 1957

Voltage 110/220Kv

Ratio 300-150-75-/1/1/1

Power 60VA

Class 0.5 & S20

I Therm 24/12/6

1 Dyn 60/30/15

TRANSFORMER CTs (TCT-4)

Make Transformer &Electricals Kerala Ltd-TELK

Manufacturing No. 220104

Sl No. 1R,2R,3R

PO No. 19109211 Dt:21/195

Type NPOULVZ-R

Basic Ins level 230/550Kv

Rated Voltage 126Kv

1995

Frequency 50 Hz

Standard Is 2705(Parts 1,2,3) 1992

VOLTAGE TRANSFORMER

This is a step down transformer, which step down the high voltage to a value that can be measured using the measuring instruments in the control room. This has an additional core for the carrier communication. The CVT are connected between phase and ground in parallel to the circuit.

CAPACITOR VOLTAGE TRANSFORMER VOLTAGE TRANSFORMER

REFERENCES

IEEE RED DATA BOOK, 1993

NEWNESS ELECTRICAL ENGINEER’S HAND BOOK, D.F.WAENE, SECOND EDITION.

ISO MANUAL ELECTRICAL SYSTEM STUDY AND FAULT LEVEL CALCULATION BY FEDO.

POWER GENERATION OPERATION ANDCONTROL BY ALLEN JWOOD AND BRUDE T W WOLLENBERG.

ISO MANUAL FOR EARTHING AND SYSTEM STABILITY CALCULATION BY FEDO.

STD 80-2000 IEEE GUIDE FOR SAFETY