sop presentation ttps 1

8/13/2019 SOP Presentation TTPS 1

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STARTING OIL PUMP IN

SERVICE PROBLEM AT

NTPC,TTPS UNIT#5 ,110 MW UNIT

Objective

To study the Main oil pump discharge

pressure not sustaining when unit isrunning on load



Brief Description of TG Lub

oil System When the Turbine Generator is on BarringGear and on Full speed No load ( FSNL ) ,

Starting oil pump ( SOP ) supplies Lub oil to allbearings , Governing system , Airside seal oilsystem, MOP suction .

When the machine is rolled to 3000 rpm ,

Main oil pump ( MOP ) takes over the duty ofsupplying Lub oil to TG Bearings , Governingsystem , Airside seal oil system .



Observations :

• As we switch off the SOP after unit issynchronized to Grid , MOP dischargepressure is taking a dip of 4-5 Kgf/cm2

from 10.5 Kgf/cm2 to 5.5 –

6.5 Kgf/cm2which is resulting in Auto start of SOP .

• If the SOP is not coming into service ,

Turbine is getting tripped and the unit # 5has tripped 2 times so far because of thisaccount.



Problem faced : • When the SOP is switched off either at

FSNL ( 3000 rpm ) or when the unit is

on load ,

• MOP Discharge pressure is not holding

at a constant value , but it is varying by

4-5 Kgf/cm2 resulting in dip of

discharge pressure . Hence the TurbineGenerator is getting tripped .



Major jobs carried out during

Annual OH – 2009 of Unit # 5 No Turbine cylinders were overhauled

6 Nos of TG Lub oil system NRV's serviced

2 Nos of SOP Discharge valves , MOP Suction isol. valve, MOP Disch. to Lub oil coolers isol. valve serviced

TG Lub oil cooler bundles replaced with New design

( Finned tubes ) bundles of M/s Laxmi EngineeringIndustries ,( Bhopal ) Pvt Ltd make

Air side and Gas side Seal oil pumps replaced with Newpumps of M/s Tushaco make Gear pumps

2 out of 3 Logic has been introduced in this overhaul by

C&I in DDCMIS Generator Rotor , Seal Rings replaced during Gen.

Rotor thread out operation



Post Overhauling works 2 Nos of NRV’s one in MOP suction line

from SOP Discharge , SOP Discharge to

Gov. system oil line were replaced with

New ones – No change in SOP running status while unit is on Load

ONE no. of SOP replaced with overhauled

pump – No change in SOP running status while unit is on Load

•



Brain storming

/Recommendations

• Oil Injector which is providing MOP

suction needs inspection • All NRV ‘s in TG Lub oil system

servicing • MOP Inspection & Seal rings

replacement if required • Governing system inspection • Lub oil Orifices inspection/rectification



Suggestions to solve the above

problem by the Esteemed

members We welcome your valuable suggestions



REPEATED FAILURE OF OMEGA

PIPE GASKET AT NTPC , TTPSSTAGE – 2 UNITS ( 2*110 MW )

• Brief Introduction of the Problem : What is OMEGA pipe ?

– It is nothing but an IP Turbine Steam Inlet pipe in the

form of symbol OMEGA . – Omega pipe is having LHS & RHS Steam inlet pipes

and a common inlet on the IP cylinder facing – Steam leakage was observed from LHS Flange of

Omega pipe in Dec ,2008 & Jul , 2009 in Unit # 5

– Resulting in Unit # 5 Outage on 2 occasions



Observation of the Problem : • Steam leakage from LHS Flange of

Omega pipe of Unit # 5 was due to

the failure of Old Serrated Gasket of

material SS – 316 .

• May be due to thermal shocks

during Load changes/Transient

operating conditions.



Remedial measures : A New modified Gasket with more outside

diameter to hold between the Studs beingused .

Camprofile gasket with Graphite sheathingon both sides used with higher OD toarrest the leakage .

Support system for the IP Steam chestLHS /RHS will be thoroughly inspectedduring next Annual Overhaul .



Suggestions by the Esteemed

members

• We welcome your valuable suggestions

sop presentation ttps 1

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