HI

I would like to clear my doubt on TNR. Why TNR is greater than TNH. How TNR is calculated? Can you please give me the explanation with simplified drawing.

thanks in advance

AK

 

HI

Please use the 'Search' function of control.com and search for Droop Speed Control or TNR or Turbine Speed Reference.

 

TNR is turbine reference value whereas TNH is the actual turbine speed. The turbine droop function has to be ascertained which can serve as reference to reach TNR.

 

AK,

Please reply your email address here and I will email to you some simplified logic diagram about TNR (TNRV1).

JM

 

>Please reply your email address here and I will email to you some simplified logic diagram about TNR (TNRV1). <

my email address is :- [email protected]

 

Girish,

email sent. please see rung ladder diagram attached. Hope that will help you understand TNR.

Some pointers as follows:

Max setpoint of TNR on normal operation will be 107% (TNKR3) and GT will automatically stop if reached.

If the ELECTRICAL OVERSPEED TRIP TEST selected. The maximum TNR will automatically set to 111.5% (TNKHOST) so that the test can be successfully achieved. Electrical overspeed trip test at 110%.

When breaker is open, TNR will be 100.3% (TNKR2)


DROOP SPEED CONTROL REFERENCE (TNRV1)
Input
L83HOST - HP overspeed test signal.
L83LOST - LP overspeed test signal.
TNKHOST - HP overspeed test setpoint.
TNKLOST - LP overspeed test setpoint.
TNKR3 - TNR maximum limit.
TNKR4 - TNR minimum limit.
LTNROP - TNR minimum speed selector.
TNKR5 - TNR startup minimum.
L70L - Droop speed setpoint lower.
L70R - Droop speed setpoint raise.
L83JD0 Boolean TNR increment rate 0.
. . .
. . .
. . .
L83JD11 Boolean TNR increment rate 11.
TNKR1_0[12] - TNR ramp rate constants, %N/sec.
TNKR2 - TNR breaker open preset.
TNKR7 - Startup preset.
L83PRS1 - Breaker open speed preset.
L83PRS2 - Startup speed reset.

Output
L33CDMN - Droop speed setpoint at MIN limit.
L33CDMX - Droop speed setpoint at MAX limit.
TNR - Turbine HP speed setpoint.

3 ways to INCREASE the TNR by L70R

Ladder 1.
Input
E L70RX Speed/Load setpoint Raise Aux signal NO
A L70R_C If Local Grid Operation active – True (L43GRID_OPOK) NC
B L83SCI_ Island frequency control mod NC
C L70L Droop speed setpoint lower NC
D L33CDMX TNR at maximum NC
H LFSRCPR COMP operating limit control / Backup FSR active NC
I L70R_D HRSG high steam temp protection NC

Ladder 2
Input
B L83SCI_ Island frequency control mode NO
G L70IR Isoch Speed Load Setpoint is TRUE NO
C L70L Droop speed setpoint lower NC
D L33CDMX TNR at maximum NC
H LFSRCPR COMP operating limit control / Backup FSR active NC
I L70R_D HRSG high steam temp protection NC

Ladder 3
Input
F L70R_B If Local GRID Operation – Load raise TD - TRUE(L70GRD_RAISE) NO
C L70L Droop speed setpoint lower NC
D L33CDMX TNR at maximum NC
H LFSRCPR COMP operating limit control / Backup FSR active NC
I L70R_D HRSG high steam temp protection NC

Note:
Inputs C, D, H and I are all NC
L70R inhibit raise if L70L is active. (L70L priority)
NO - Normally Opened
NC - Normally Closed

13 ways to DECREASE the TNR by L70L

Ladder 1.
Input
A L70LX2 Base to peak transient lower NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 2.
Input
H L70LX3 Shutdown lower (High steam temp – Load runback required) NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 3.
Input
D L70LX4 Local manual lower NO
B L83SCI_Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 4.
Input
E L70LX5 High temp spread lower NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 5.
Input
F L70LX6 Auto Synch lower signal NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 6
Input
I L70LX7 Plant DCS auto lower setpoint logic NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 7.
Input
J L70LDLN DLN auto lower NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 8.
Input
L L70LX Aux load lower NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 9.
Input
G L70L_A If Temp match Govern Lower (L90TML) is TRUE(Decrease TTXM with TNR) NO
B L83SCI_ Island frequency control mode NC
C L33CDMN TNR at minimum NC

Ladder 10.
Input
B L83SCI_ Island frequency control mode NO
I L70LX7 Plant DCS auto lower setpoint logic NO
C L33CDMN TNR at minimum NC

Ladder 11.
Input
M L83CBLIMIT CBV failed to close – load limiting NO
C L33CDMN TNR at minimum NC

Ladder 12.
Input
N L70L_B If L70GRD_LOWER is true (Local Grid Operation – Load Lower TD) NO
C L33CDMN TNR at minimum NC

Ladder 13.
Input
K L70L_76 Fuel gas system lower due to wobbe index NO

L70GRD_LOWER and L70GRD_RAISE are use in PFR ON (Primary Frequency Regulation - ON).

As much as I want to give more information about were all those inputs comes from, it is very hard in this forum due to not possible to attached rung ladder diagram. I hope by giving you these inputs you will know why TNR is increasing or decreasing.

Goodluck.

JM