power distribution of a steel plant

8/13/2019 Power Distribution of a Steel Plant

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Presented by

Alok GKeerthana A.N.

Md.Kashif hussain

Shruthi S.M.


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Project overview

Maximum demand calculation

Load flow studies Short circuit studies

Protection

Relay coordination


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This Project is actually the brown field expansionof a 0.6 MTPA Pellet plant to 1.8 MTPA integratedsteel plant.

Existing Facilities include the following:

25 MW power plant

70 MW power plant

2 x 1.2 MTPA beneficiation plant

2x1.2 MTPA pellet plant

4 x 500 TPD DRI Plant

A small capacity bar mill.


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Expansion to 1.8 MTPA Integrated Steel Plant isplanned in two stages of 0.9 MTPA each.

The major units envisaged in Stage-I and Stage-IIare as follows:

100T EAF/LF

Oxygen Plant

Sinter Plant

Blast Furnace

Coke Oven

Bar Mill And Billet Caster


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The existing plant receives power at 220 kV fromnearby switching station, located approximately 17kms away from the plant.

In addition to the grid supply, in-house generationfrom 25 MW and 70 MW CPPs also caters to the loaddemand.

Excess power generated after meeting the demand ofthe plant is exported to the Grid.


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To cater to the increased demand of the power dueto expansion of the plant , an additional capacity of140 MW (2x70 MW CPPs) generation is also planned tobe set up.

For feeding the new plant units at 33 kV, a new220/33 kV Main Receiving Substation (MRSS) isplanned.

The interconnection of the existing power system,CPPs and new MRSS and CPPS is planned through anumber of interconnections considering variousfactors to ensure maximum availability andreliability.


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Maximum demand calculations Transformer selection

Load flow analysis Short circuit analysis

Selection of Protective equipments Relay co-ordination


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Shop/UnitProduction(Tonnes/yr)

Workingdays/year

Workinghours/year

Sp. EnergyConsumption(kW h/Tonnes)

Annu al EnergyConsumption (kWh)

Average Lo ad(MW)

Load FactorMaximum Demand (MD)

in 15 Min. (MW)

PHASE-1

RAW MATERIAL YARD To Unit

Raw Coal Coke Oven 802569 365 8760 8 6420552 0.73 0.85 0.86

Sinter Sinter Plant 1478798 350 8400 8 11830384 1.41 0.85 1.66

Lime stone Lime Plant 187186 320 7680 8 1497488 0.19 0.85 0.23

RMHS Total Load 59636718 8.56

BLAST FURNACE

GHM B.F Output 910000 350 8400 175 159250000 18.96 0.8 23.70

COKE OVEN

COKE CO Output 450000 350 8400 60 27000000 3.21 0.8 4.02

SGP

SLAG SGP 318500 365 8760 25 7962500 0.91 0.8 1.14

EAF/LF

EAF/LF Auxil laries EAF/LF 1100000 320 7680 50 550000 00 7.16 0.9 7.96

PIG CASTING MACHINE


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Step-1Calculation of Annual Energy Consumption

Step-2Calculation of Average Load of each unit

Step-3 Calculation of individual maximum demand of each unit

Step-4calculation of total maximum demand

Step-5calculation of simultaneous maximum demand considering 3% losses

Step-6calculation of total maximum demand considering 5% contingency

Step-7 calculation of total energy requirements per annum


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Sum of Individual Maximum Demand (considering 3% losses) =83.45MW

Max. Demand (MD) (considering diversity factor of 1.25) = 66.76MW

Max. Demand (MD) (considering 5% contingency requirement) =3.34 MW

Total load demand =70.10MW

Total EAF demand=106.0MW

Total Energy consumption per annum (considering 3% losses) = 18089046.94kWh

Total Energy requirement per annum = 621.06MkWh


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Transformer selected will have the rating twicethe calculated MVA for each load.

For 70 MW plant loads, transformer selected is,63/80 MVA

For 106 MW EAF load, transformer selected is,

130/160 MVA


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Load flow studies are carried out to determine thepower flow in the system.

Load flow studies helps in planning the operation of

power system under existing conditions, itsimprovements and future expansion.

The study also helps to identify

Overloading of transmission lines Voltage limit violations at the buses


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Case-1: Grid and 25MW CPP feeding existing loads

Case-2: Grid and 95MW (1x25 & 1x70) CPPs feeding existingloads

Case-3:Grid and 95MW (1x25 & 1x70) CPPs feeding existingloads and phase-1 loads.

Case-4:Grid and 165MW (1x25 & 2x70) CPPs feeding existingloads, phase-1 and phase-2 loads.

Case-5: Grid and 235MW (1x25 & 3x70) CPPs feeding existingloads, phase-1 and phase-2 loads.


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DESCRIPTION GENERATION GRID 25MWCPP

70 MWCPP-1

70 MWCPP-2

70 MWCPP-3

LOAD

CASE-1 MW 35.41 25 0 0 0 60.05

MVAR 14.09 20.30 0 0 0 37.22


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! NUMBER OF LINES LOADED BEYOND 125%: 0@ NUMBER OF LINES LOADED BETWEEN 100% AND 125%: 0# NUMBER OF LINES LOADED BETWEEN 75% AND 100%: 0$ NUMBER OF LINES LOADED BETWEEN 50% AND 75%: 0^ NUMBER OF LINES LOADED BETWEEN 25% AND 50%: 1& NUMBER OF LINES LOADED BETWEEN 1% AND 25%: 6

* NUMBER OF LINES LOADED BETWEEN 0% AND 1%: 1

FROM

NODE FROMNAME TONODE TONAMEFORWARD LOSS %

LOADIN

GMW MVAR MW MVAR1 Bus1 2 Bus2 27.866 21.65 0.1313 0.0912 27.6 ^4 Bus4 3 Bus3 -21.915 -12.477 0.0283 -0.0417 3.2 &2 Bus2 5 Bus5 12.845 7.952 0.0243 -0.006 11.9 &2 Bus2 6 Bus6 14.008 8.676 0.0289 -0.0018 12.9 &7 Bus7 8 Bus8 35.443 15.98 0.0482 -2.5716 17.8 &12 Bus12 8 Bus8 LINE IS OPEN8 Bus8 14 Bus14 0 -0.028 0 -0.0282 0.0 *12 Bus12 14 Bus14 LINE IS OPEN1 Bus1 19 Bus19 -4.661 -1.371 0.0025 -0.0262 3.8 &20 Bus20 2 Bus2 2.32 1.194 0.0007 -0.0275 2.1 &


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DESCRIPTION GENERATION GRID 25MWCPP 70 MWCPP-1 70 MWCPP-2 70 MWCPP-3 LOAD

CASE-2 MW (-) 34.42 25 70 0 0 60.05

MVAR 3.99 6.47 25.85 0 0 37.22


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! NUMBER OF LINES LOADED BEYOND 125%: 0@ NUMBER OF LINES LOADED BETWEEN 100% AND 125%: 0# NUMBER OF LINES LOADED BETWEEN 75% AND 100%: 0$ NUMBER OF LINES LOADED BETWEEN 50% AND 75%: 0^ NUMBER OF LINES LOADED BETWEEN 25% AND 50%: 1& NUMBER OF LINES LOADED BETWEEN 1% AND 25%: 6* NUMBER OF LINES LOADED BETWEEN 0% AND 1%: 1

FROM

NODEFROM

NAMETO

NODETO

NAME

FORWARD LOSS%

LOADINGMW MVAR MW MVAR

1 Bus1 2 Bus2 34.476 13.555 0.1446 0.1034 28.9 ^4 Bus4 3 Bus3 34.75 -1.559 0.051 -0.0247 4.3 &2 Bus2 5 Bus5 12.85 7.952 0.0243 -0.006 11.9 &2 Bus2 6 Bus6 14.012 8.675 0.0289 -0.0018 12.9 &7 Bus7 8 Bus8 -34.39 6.838 0.0387 -2.6328 15.9 &12 Bus12 8 Bus8 LINE IS OPEN8 Bus8 14 Bus14 0 -0.028 0 -0.0284 0.0 *12 Bus12 14 Bus14 LINE IS OPEN1 Bus1 19 Bus19 -11.245 -8.123 0.0203 -0.0101 10.8 &20 Bus20 2 Bus2 8.924 7.5 0.0144 -0.0151 9.1 &


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LOAD FLOW ANALYSIS-CASE 3


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70 MWCPP-1

70 MWCPP-2

70 MWCPP-3

LOAD

CASE-3 MW (-)163.54 25 70 70 70 69.85

MVAR 19.90 6.31 25.35 2.50 2.5 43.3


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! NUMBER OF LINES LOADED BEYOND 125%: 0@ NUMBER OF LINES LOADED BETWEEN 100% AND 125%: 0# NUMBER OF LINES LOADED BETWEEN 75% AND 100%: 0$ NUMBER OF LINES LOADED BETWEEN 50% AND 75%: 2^ NUMBER OF LINES LOADED BETWEEN 25% AND 50%: 1& NUMBER OF LINES LOADED BETWEEN 1% AND 25%: 5* NUMBER OF LINES LOADED BETWEEN 0% AND 1%: 0

FROMNODE

FROMNAME

TONODE

TONAME

FORWARD LOSS %LOADING

MW MVAR MW MVAR

1 Bus1 2 Bus2 34.47 13.339 0.144 0.1028 28.9^

4 Bus4 3 Bus3 34.754 -2.266 0.0511 -0.0246 4.4&

2 Bus2 5 Bus5 12.85 7.952 0.0243 -0.006 11.9&

2 Bus2 6 Bus6 14.013 8.675 0.0289 -0.0018 12.9&

7 Bus7 8 Bus8 -163.08 26.426 0.8468 1.6732 73.7$

12 Bus12 8 Bus8 129.549 -14.312 0.0524 -0.0049 57.9$

8 Bus8 14 Bus14 LINE IS OPEN

12 Bus12 14 Bus14 LINE IS OPEN

1 Bus1 19 Bus19 -11.24 -8.124 0.0202 -0.0101 10.8&

20 Bus20 2 Bus2 8.924 7.494 0.0144 -0.0151 9.1&


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70 MWCPP-1

70 MWCPP-2

70 MWCPP-3

LOAD

CASE-5 MW 77.91 25 70 70 0 240.95MVAR 74.38 9.45 35.60 13.60 0 107.185


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FROMNODE FROMNAME TONODE TONAME FORWARD LOSS %LOADING

MW MVAR MW MVAR1 Bus1 2 Bus2 34.545 16.371 0.154 0.112 29.9^4 Bus4 3 Bus3 34.67 7.673 0.0532 -0.0227 4.4&2 Bus2 5 Bus5 12.848 7.952 0.0243 -0.006 11.9&2 Bus2 6 Bus6 14.011 8.675 0.0289 -0.0018 12.9&7 Bus7 8 Bus8 77.909 74.381 0.3656 -0.8488 48.8^12

Bus12

8

Bus8

25.511

-2.3

0.0021

-0.2645

11.6&

8 Bus8 14 Bus14 137.478 75.849 0.0079 0.0144 70.9$12 Bus12 14 Bus14 39.256 5.293 0.005 -0.2489 17.9&1 Bus1 19 Bus19 -11.32 -8.113 0.0204 -0.0099 10.9&20 Bus20 2 Bus2 8.917 7.565 0.0145 -0.015 9.2&


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70 MWCPP-1

70 MWCPP-2

70 MWCPP-3

LOAD

CASE-4 MW 12.97 25 70 70 70 245.85MVAR 74.59 8.97 34.02 34.02 34.02 110.22


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FROMNODE

FROMNAME

TONODE

TONAME

FORWARD LOSS %LOADING

MW MVAR MW MVAR

1 Bus1 2 Bus2 34.536 16 0.1527 0.1107 29.7^

4 Bus4 3 Bus3 34.679 6.458 0.0525 -0.0233 4.4&

2 Bus2 5 Bus5 12.848 7.952 0.0243 -0.006 11.9&

2 Bus2 6 Bus6 14.011 8.675 0.0289 -0.0018 12.9&

7 Bus7 8 Bus8 12.967 74.59 0.184 -1.8226 34.9^

12 Bus12 8 Bus8 59.441 -2.078 0.0112 -0.2169 26.8^

8 Bus8 14 Bus14 106.64 75.626 0.0054 0.0013 58.9$

12 Bus12 14 Bus14 70.099 5.498 0.0157 -0.193 31.7^

1 Bus1 19 Bus19 -11.31 -8.115 0.0204 -0.01 10.9&

20 Bus20 2 Bus2 8.918 7.557 0.0145 -0.015 9.2&


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Losses in the system are calculated.

No buses or Lines are getting overloaded.

No need for additional generation andinductive VAR support or placement ofcapacitors to maintain system voltages

within specified limits is found.


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Short circuit calculations provide currents andvoltages on a power system during faultconditions.

Short circuit study calculates the maximumavailable short circuit current at various pointsthroughout the system and the calculatedvalues are then used to evaluate the

application of protective devices, and todevelop circuit breaker trip settings.


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Case-1: Grid and 25MW CPP & 70 MW CPP

Case-2: with grid and all CPP sources (1x25 & 3x70MW)


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BUS NUMBER BUS VOLTAGE MVA LEVEL

FAULT CURRENT

(kA)

Bus1 11 587.1 30.815

Bus2 11 591.4 31.04

Bus3 11 1013.5 53.197

Bus4 11 1011.7 53.1Bus5 11 556.7 29.219

Bus6 11 556.7 29.219

Bus7 220 7267.9 19.074

Bus8 220 3510.1 9.212Bus19 11 572.2 30.032

Bus20 11 575.1 30.188


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BUS NUMBER BUS VOLTAGE MVA LEVEL FAULT CURRENT(kA)

Bus1 11 591.8 31.064

Bus2 11 596.3 31.297

Bus3 11 1028.1 53.961

Bus4 11 1025.8 53.844

Bus5 11 561 29.447

Bus6 11 561 29.447

Bus7 220 7641 20.053

Bus8 220 3946.1 10.356

Bus9 11 882.2 46.307

Bus10 11 882.2 46.307

Bus12 220 3842.9 10.085

Bus14 220 3924.2 10.299

Bus15 33 537.4 9.402Bus16 33 537.4 9.402

Bus17 33 965.4 16.89

Bus19 11 576.7 30.269

Bus20 11 579.8 30.432


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Short circuit studies provide post fault busvoltages at different buses in the network fora fault at any location in the network.

These results are typically given as faultMVA.

Short circuit studies for minimum fault levelcondition is of interest in relay coordination

to check whether relays can distinguishbetween the Maximum Load Currents andMinimum Fault Currents.


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The purpose of an electrical power system is togenerate and supply electrical energy to consumers.The system should be designed and managed to deliverenergy to the utilisation points with both reliability and

economy.Protection should be done to prevent the following:

Prevent any disruption of supply

Electrical equipment used is very expensive and weshould prevent any damage to the equipment

Power system should operate in a safe manner atall times

Fault may represent a risk to life and property


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Maximum protection

Minimum equipment cost

Reliable protection

High-speed operation Simple designs

High sensitivity to faults

Insensitivity to normal load currents

Selectivity in isolating a minimum portion ofthe system


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For attaining higher reliability, quick action and

improvements in operating flexibility of the protection

schemes, separate elements of a power system , in addition

to main or primary protection , are provided with a back-up

and auxiliary protection.

ProtectionZone B

ProtectionZone A

To Zone BRelays

To Zone ARelays


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Short-circuit protection includes two protection systems: primaryand backup protection. Primary protection is the first line ofdefense.

Back up protection gives back up to the main protection, whenthe main protection fails to operate or is cut out for repairs etc.


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PROTECTION EQUIPMENT AND DEVICES

Relays

Current Transformers CTs

Voltage Transformers VTs or PTs

Circuit Breakers CBs etc.


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Protection function can be classified asfollows:

Back up protection

(Over current and Earth Fault) Power transformer protection

(Unit or Differential Protection)

Distance protection

Differential protection Busbar protection, etc.


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Application

The most commonly used protective relays arethe instantaneous overcurrent relays. They areused as both primary and backup protective

devices and are applied in every protective zonein the system.


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Restricted earth faultprotection is provided inelectrical powertransformer for sensinginternal earth fault of thetransformer


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FaultLoad

Radial Line

The current decreases as the distance increases,This indicates that the operation time of the relaywill be larger as the current is farther from thesource. This is one of theadvantages of inverse-type overcurrent relays.

RELAYOPERATIONTIME

Current (A)

Time (s)


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Distance protection uses current and voltageinformation to make a direct, or indirect,estimate of the distance to the fault.

Application

Distance relays are widely used for primary andbackup protection on transmission lines wherehigh-speed relaying is desired.

Other applications include generator backup

protection for faults on the system and startup oflarge motors with high inertia.


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Application

Synchronism check relays are applied when twoor more sources of power are to be connected toa common bus.


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K

L

The arrows shown in the figure areused to represent the protection

tripping direction. Note that therelays are oriented towards theprotected lines. This orientationdivides the system protection intotwo independent groups: the relayslooking to the right and those

looking to the left. Thedirectionality divides thecoordination process into twoindependent processes. A relay onlyneeds to be coordinated with theother relays in its group.


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Application

Directional overcurrent relays are used toprovide sensitive tripping for fault currents inone(tripping) direction and not trip for load or

fault currents in the reverse (normal) direction.


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ExternalFault

IDIF = 0

CT CT

50

Balanced CT Ratio

ProtectedEquipment

If the primary andsecondary currentsat both sides of the

protected

equipment areequal. There willbe no difference,and the relay will

not operate.


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InternalFault

IDIF

> ISETTING

CTR CTR

50

Relay Operates

Protected

Equipment

For an internalfault, the

secondary currents

are 180 out ofphase and produce

a differentialcurrent through theovercurrent relay.If this differentialcurrent is larger

than the pickup forthe relay, the relay

will trip bothcircuit breakersinstantaneously.


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Bus protection

Transformer protection

Generator protection

Line protection Large motor protection

Reactor protection

Capacitor bank protection

Compound equipment protection


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The basic idea of coordination is that thebackup relay should be slower than theprimary relay, with a minimum separation ofTbetween curves calculated as follows:

tbackup= tprimary+ T


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Distance

Distance

t

I

} } }T T T


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For relay R1,CT chosen =1600/1AMaximum fault current(I) = 10.297kACurrent setting(IS)=130% of 1600A =2080A

For t=0.15s, TMS=0.035


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By performing various system studies using MiPower, the following thingswere concluded:

From the results of Load flow analysis it is verified that:

No bus or transmission line is getting overloaded.

Real and Reactive power requirement or excess under variousoperating conditions is found.

Loading of transformers is verified.

From the results of Short circuit analysis following observations aremade:

Required rating of equipments and Interrupting capacities ofbreakers is found.

No requirement for change in the existing system on account ofexpansion and capacity addition was found.

Short circuit levels obtained at various buses is used as input forrelay coordination.

From the results of Relay Coordination following observations aremade:

Settings for over current relays at various feeders were given andcoordination between them was verified.


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THANK YOU

power distribution of a steel plant

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