Summer training presentation on thermal plant in jindal steel and power limited ( dongamahua captive power plant)

SUMMER TRAINING PRESENTATION

IN THERMAL POWER PLANT

ATJINDAL STEEL & POWER

LTD. (C.G.)PRESENT BY:

AMIT BANSALBE- ELECTRICAL

101204012

JSPL is an steel and energy company Founded in 1969 by late O.P. Jindal Third largest producer of steel in India 11th fastest growing company in India Its turnover is around US$ 3.56 billion Chairman- Mr. Naveen Jindal

COMPANY PROFILE

Situated in Dongamahua, a village in Raigarh district of Chattisgarh

It is a captive power plant with capacity 4*135 MW

Coal used is low grade coal Coal supply is from Dongamahua

captive coal mines Two transmission lines one line is going

to JPL, Tamnar and other line is going to JSPL, Raigarh

Power is transmitted at 220 kv

POWER PLANT OVERVIEW

Turbines are steam driven Fuel used is coal Turbine is mechanically coupled with

generator (135 MW) Works on Rankine cycle

THERMAL POWER PLANT

RANKINE CYCLE

WORKING OF THERMAL POWER PLANT

provides the facility of switching, control and protection of electric power

Power is transferred at 220 kv Total 16 bays Switchyard equipments are grounded by two

earthing connections

220 KV SWITCHYARD

Automatically operated switch Protect electrical circuits from overload or

short circuit Detect fault condition and interrupt the

flow SF6 has high insulating property & high

electronegativity i.e. has high affinity to absorb electron

Operated at ON load condition

SF6 CIRCUIT BREAKER

Manually operated mechanical switch which isolates a part of circuit from system as and when required

operated at off load condition Must be open after circuit breaker is open

and must be close before circuit breaker is closed

ISOLATOR

Static machine used for step up or step down current/voltage.

In DCPP there are 4 different ratings of transformer are used

Generating Transformer Substation Transformer Unit auxiliary Transformer Mines substation Transformer

POWER TRANSFORMER

Critical link between power station and the transmission network

Rating is 180 MVA Step up 13.6 KV to 220 KV Windings in GT are star-delta connected Total 4 GT’s

GENERATING TRANSFORMER

Rating is 40 MVA Used when either the unit or plant shut

down takes place So to start the plant or unit they take the

power from JPL Windings are star-star connected Step down transformer Total 3 ST’s

SUBSTATION TRANSFORMER

Rating 25 MVA Used to run the auxiliaries of the plant Once with the help of ST’s unit is started

then after disconnecting ST generated power is utilized with the help of UAT

Directly connected to the generator output Windings are delta-star connected Step down 13.6 KV to 6.9 KV Total 4 UAT’s

UNIT AUXILLARY TRANSFORMER

Coal supply in DCPP is from their captive mines

So, to supply power to mines MST’s are used

Rating is 50 MVA Total 2 MST’s

MINES STATION TRANSFORMER

In DCPP oil immersed transformers are used Mineral oil is used Provides insulation to the winding and act

as coolant Protects windings from direct contact with

oxygen

TRANSFORMER OIL

transformer goes under thermal & electrical stresses

Gases are produced due to decomposition of transformer insulating oil

Affect the insulation of winding When fault is major, production of

decomposed gases are more & collected in buchholz relay

But when gases are not significantly high they get dissolved in oil

TESTING OF TRANSFORMER OIL

Amount of gases are analyzed by DGA kit

General gases found are hydrogen, ethane, methane, ethylene, acetylene, carbon monoxide, carbon dioxide, nitrogen and oxygen

DISSOVED GAS ANALYSIS TEST

GAS APPROVED LIMIT(ppm) H2 100

CO2 2500 C2H2 2 CO 350

C2H4 50 C2H6 65 CH4 120

DGA KIT EQUIPMENT IN WHICH OIL IS KEPT

Dielectric strength of oil is known as breakdown voltage of transformer oil

Measured by observing at what voltage sparking occurs b/w two electrodes separated by 2.5 mm gap

Low value of BDV indicates that presence of moisture

Minimum value of BDV at which transformer oil can safely be used is 50kv

BREAKDOWN VOLTAGE TEST

BDV KIT

measure insulation resistance in MΩ Test should be run between each winding

and ground and between each pair of winding

Low value indicates that transformer is the problem

Polarization index, P.I.=R10/R1 P.I. must be greater than 2

INSULATION RESISTANCE TEST (MEGGER TEST)

Polarization index Condition of winding

Measures to be taken

<1 Hazardous Dry winding

1-1.5 Bad Dry winding

1.5-2 Doubtful Drying is recommended

2-3 Adequate  

3-4 Good  

>4 Excellent  

MEGGER KIT

When load is increased, insulating oil of the transformer gets heated up, expands and expels in conservator tank and subsequently pushes out the dry air through silica gel breather When oil cools down, air from atmosphere is drawn into the transformer. During this to prevent moisture from entering silica gel is used. When silica gel breather absorb moisture it turns from blue to pink

TRANSFORMER BREATHES!!!

SILICA GEL BREATHER

Due to flowing of current oil gets heated Rating of transformer depends upon

allowable temp. rise limit So to prevent transformer oil from excessive

heating, radiators are used It increases the surface area of oil Can further be accelerated by using cooling

fans

RADIATOR

Oil temp. indicator60-65 – alarm – fan on90-95 – transformer trip

SINGLE LINE DIAGRAM OF

DCPP