LUBE OIL SYSTEM The lube oil is circulated to the two main bearings of the gas turbine, generator gen erator bearings, various turbine accessories, flexible couplings and load equipments. A portion of oil is diverted and filtered for use by the various hydraulic control devices d evices and functions as hydraulic control oil. Lube oil system consists of three numbers of oil pumps: Main oil mump !ve displacement, accessory gear drive " Auxiliary lube oil pump A#, centrifugal " Auxiliary lube oil pump A#, centrifugal "
MOP output pressure to the lube oil system is limited by a pressure relief valve $%&'" to (.) *sc. AOP, when A# power is is available for turbine turbine start&up and shut&down sequence, the system system lube oil is supplied by the A# auxiliary lube oil pump A+" during the time that the speed of M+ is enough to develop sufficient pressure. At gas turbine start&up, this pump starts to run automatically. This pump continues to run until the gas turbine reaches approximately -) speed signal '(/0", and at this point the pump will shut&down and the system pressure will be maintained by M+. +n gas turbine shut&down, the A# auxiliary lube oil pump starts with the closure of speed signal contact '(/0" when gas turbine sped drops to a value in between 1) and -2. The pump continues to run throughout the shut&down sequence and cool&down period. A+ will start automatically when header pressure falls below a preset value. EOP, when A# power is not available, the 3# emergency pump starts and provides bac4&up for the auxiliary lube oil pump as follows &5 i " At turbine start-up, the DC emergency pump starts automat automatica ically lly.. The pump will will continu continuee to run after 40% gas turbine turbine speed speed !4"A# !4"A# if the system system pressure has not reached the setting of the pressure switch $&'#. $&'#. ii " During " During ratcheting se(uence this pump will run e)ery minutes, in parallel p arallel with ratchet pump to sa)e the batteries.
PARAMETER ump type ump capacity 3ischarge pressure 0peed 3rive ower rating
LUBE OIL PUMP DETAILS MOP AOP 6 ear #entrifugal '1(' LM '1(' LM (.(8 *sc. (.)1 *sc. '(') %M 9-22 %M Accessory gear A# motor 0haft&driven 1.) *;
EOP #entrifugal -(7 LM 9.'' *sc. '1)2 %M 3# motor 1.) *;
CONTROL OIL SYSTEM PURPOSE To control fuel gas stop< speed ratio and control valve.
p rotection circuit of the gas turbine. To supply proper oil pressure to machine protection
The control oil is supplied from the gas turbine=s lube oil system and hydraulic system. The oil supplied from the lube oil system is connected to the low pressure trip oil circuit through an orifice, and supplies oil to the gas turbine over&speed trip valve, the manual emergency trip valve and fuel oil stop valve. Loss of oil pressure, through operation of any one of these components, reduces trip oil circuit pressure to almost to >ero, causing the piston of the fuel shut&off valve to drop shutting&off fuel flow to the gas turbine.
CONTROL PHILOSOPHY LUBE OIL PRESSURE CONTROL
a" The diaphragm operated regulating valve $%&9" is installed up&stream of the lube oil coolers". The valve maintains the bearing header oil pressure at design pressure. The valve receives a pressure signal from header bearing oil header" and when the header pressure exceeds the control valve setting, the valve opens and dumps the oil to the lube oil tan4. b" The spring loaded, diaphragm operated valve $%&'" is installed in the lube oil tan4. The valve provides the necessary pressure for hydraulic trip circuit. Trip oil circuit pressure is extracted from the M+ discharge between the pump and the pressure regulating valve $%&'". This valve throttles the M+ discharge as necessary, to assure that the hydraulic trip circuit is pressuri>ed to the required value during the firing sequence. The valve is closed during start&up, and opens as the trip circuit reaches the design point. The valve is by&passed by an orificed passage to ensure that oil is never completely shut&off from the bearing feed header. 3uring shut&down sequence also this orifice provides minimum flow of oil to assure that oil is never completely shut&off from bearing header. Trip oil from M+ $%&' $ to bearing hdr.
$%&'
+rifice diameter ? ').- mm @earing oil header
To lube oil cooler rom B+
$%&9 rom M+
LUBE OIL TEMPERATURE CONTROL
This control system has one regulatory valve $T%&'". This valve regulates cooling water flow through lube oil cooler for temperature control purpose. LUBE OIL TANK HEATING SYSTEM A maximum viscosity of 822 00C is specified for variable operations of the control system
for bearing lubrication. A temperature switch 97DE" prevents turbine start&up if the temperature of the lubricant is lower than the setting value. Fmmersion heaters 9DT&',9" are provided to heat the lube oil. The temperature switches G97DE set ? 9'o#" and 97DL set ? '+#"H control the immersion heater operation. A+ will automatically start whenever heaters are +E to circulate the system lube oil.
LUBE OIL CIRCUIT DIAGRAM COUPLING OIL 6
7DL
T6
7DA&9
97DT
@BA%FE6 +FL /BA3B%
97D
6
M/+
/I3%ACLF# +FL
A##B00+%I 6BA% @+J
T%F +FL L+ #
L+ #
6
M+
7DA&'
6
6
M
M
M
A / +
B+
A +
0
0
0
T%F +FL #F%#CFT 3FA6%AM
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