I have a simple question: how to find redundant seismic vibration sensors from CSP? There are seven sensors used in Frame VI Gas Turbine- BB1, BB2, BB4, BB5 in Turbines, BB10, BB11 and BB12 in Generator bearings.

Turbine Bearing #1 BB1 and 2
Turbine Bearing #2 BB4 and 5
Generator Bearing #1 BB10 and 11
Generator Bearing # 2 BB12

What is utilization mask and redundant mask?

JK39R_1 D800 HEX
JK39U_1 D801 HEX
JK39U_3 70 HEX

What does this means?

Would be appreciated all your helps.

Regards,

Joy

 

Look at this: Spectral Vibration recorder

http://www.madgetech.com/shock.php#svr101

 

The first question is simple, though unclear. Can you explain what you mean by "find?" In this description, we are referring to seismic (velocity) vibration pick-up inputs to a Mk V SpeedTronic turbine control system as applied to a heavy-duty gas turbine.

It's an idisyncracy (okay, it's an annoyance!) of the CSP Documentor (really of the .pic files used to represent many BBLs which can have redundant inputs) that it doesn't specifically list or display all the inputs to the blocks. It's one of those things we all have to learn to recognize and live with (there are just so many of them for the Mk V!).

GE-built Frame 6 gas turbine-generators use ten (10) vibration sensors (three are placed on the load gear). So, your application only has seven vibration pick-ups (no seismic vibration pick-ups mounted on the load gear).

GE-built units all came with a document called the 'Control Specification', and in that document there were explanations of all the masks associated with the BBLs used in the application's CSP (at least there was supposed to be explanations). They weren't always the easiest to understand, but they were there. Unfortunately, they aren't easy to reproduce in this forum (first because of the way text is entered and second because of the proportional-spaced font used in the postings) so it can't be sent in this reply. If you have a Control Specification, look in Sect. 08.02.01 for the exact details of vibration masking.

As with any control document, a CSP is not really useful unless there are some hand-written notes. A CSP which is well-used will have LOTS of hand-written notes as the user/reader discovers things and notes them for himself/herself or others; most will also have dogeared pages and lots of Post-It notes, also. DON'T be afraid to mark-up your copy of the CSP--it's yours, and you need to make it useful, which generally includes lots of notes and references.

For the L39VVn BBL, there are twelve possible vibration sensor inputs (channels) and four basic groups of vibration sensors: turbine, load gear, generator, and "other." There are four (4) redundancy masks: one for the turbine group(JK39R_1), one for the load gear group (JK39R_2), one for the generator group (JK39R_3), and one for "other" group(JK39R_4). There are four (4) utilization masks: one for the turbine group (JK39U_1), one for the load gear group (JK39U_2), one for the Generator group (JK39U_3), and one for "other" group (JK39U_4). There is also an array of Control Constants which define which of the 12 possible channels are active (JK39_1 through JK39_12).

The utilization mask tells the L39VVn BBL which of the twelve possible inputs are used in a particular group. The redundancy mask tells the L39VVn BBL which of the vibration sensors in that group are redundant (that is, which bearings have two sensors).

The D80n values for JK39R_1 and JK39U_1 tell the L39VVn BBL that there are two vibration sensors on each of the two turbine bearings. The 007n value for JK39U_3 tells the L39VVn BBL that there are three sensors on the generator. If JK39R_3 is 0060, that tells the L39VVn BBL that the turbine-end generator bearing vibration sensors are redundant.

If the number at the far right of the utilization mask value is a "1" it indicates the group of vibration sensors is to be processed as a "redundant group." In a redundant group, the unit will not be tripped when a single active vibration transducer input is above the trip level; at least one of the active sensors in the group must also be above the alarm level for a high vibration unit trip to be initiated. If the number at the far right of the utilization mask value is a "0" any active vibration sensor input in that group which is above its trip level will initiate a unit high vibration trip.

In your case, the turbine vibration sensors are a redundant group and the generator vibration sensors are not. In order for the unit to be tripped on a high turbine vibration, at least one active turbine sensor must be above its trip level and at least one active turbine sensor must be above its alarm level. Any active generator vibration sensor which is above its trip level will initiate a unit trip.

Three-bearing machines (Frame 7s (though not F-class units) and Frame 9s (again, not F-class units)) would have different utilization- and redundancy masks (and active sensor values) because there would be an additional turbine bearing vibration sensor (and no load gear vibration sensors--except for the few Frame 7 units which used load gears to drive 50 Hz generators).

markvguy

 

Thank you Sir,

So our operation manual is wrong.

19.13.4.5 Seismic Vibration
The Vibration Levels display shows the Turbine/Generator schematic and the bar chart diagram with the vibration measurements. The table below shows the alarm and trip settings for each channel. The trip condition for the turbine group is "2out of 4", for the generator group it is "2out of 3".

This is from our Control Spec:-
1.1 VIBRATION PROTECTION
Algorithm : L39VV5_
The vibration channels selected for use on this application are indicated by logic "1" value for the specified constant C, JK39_n.
"n" is a number from 1 to 12 which represents the 12 possible vibration inputs.
"g" is a number from 1 to 4 which represents a vibration group :
1 - Gas turbine
2 - Reduction gear
3 - Generator
4 - Miscellaneous (steam turbine)
Example group definition, JK39U_g for 6001B :
Bit 0 is used to select redundant sensors.
Note : Adjust alarm levels with operating experience in the field.


JK39_8 NONEG 0 cnts Channel 8 Enable
JK39_9 NONEG 0 cnts Channel 9 Enable
JK39R_1 HEX D800 hex Vibration Channel Redundancy Mask Turbine
JK39R_2 HEX 0 hex Vibration Channel Redundancy Mask Load Red
JK39R_3 HEX 0 hex Vibration Channel Redundancy Mask Generato
JK39R_4 HEX 0 hex Vibration Channel Redundancy Mask Other
JK39U_1 HEX D801 hex Vibration Channel Utilization Mask Turbine
JK39U_2 HEX 0 hex Vibration Channel Utilization Mask Load Re
JK39U_3 HEX 70 hex Vibration Channel Utilization Mask Generat
JK39U_4 HEX 0 hex Vibration Channel Utilization Mask Other


One more doubt, How you are telling from the hexadecimal, how many sensors are used in each bearing?

Thanks & Best Regards,

Joy

 

<p>The only problem with your operation manual that can be seen is the statement "Example group definition, JK39_g for 6001B," which is incorrect.

<p>Again, this is difficult to depict because of the way text is entered and the proportional-spaced font used to display the responses here on control.com, but here goes:
<pre>
BB1 JK39_1=1 8
BB2 JK39_2=1 4 (First Hex Digit)
BB3 JK39_3=0 2 (the left-most digit)
BB4 JK39_4=1 1
------------------------------
BB5 JK39_5=1 8
BB6 JK39_6=0 4 (Second Hex Digit)
BB7 JK39_7=0 2 (from the left)
BB8 JK39_8=0 1
------------------------------
BB9 JK39_9=0 8
BB10 JK39_10=1 4 (Third Hex Digit)
BB11 JK39_11=1 2 (from the leftt)
BB12 JK39_12=1 1
------------------------------
8
4 (Fourth Hex Digit)
2 (from the left)
1
</pre>
<p>On gas turbine applications, BB1 through BB5 are for the turbine (the turbine group); BB7 through BB9 are for the load gear (the load gear group); and BB10, BB11, and BB12 are for the generator (the generator group). (It's never been clear what group BB6 belongs to....)

<p> When calculating the hex values, it's the sum of the binary values for the sensors used or redundant sensors on bearings--read on.

<p>In your application, JK39U_1, the turbine group utilization mask is D801, because BB1, BB2, BB4, & BB5 are used. That would equal 8+4+1=13=D Hex for the first digit; BB5, or 8=8 Hex for the second digit, 0 for the third- and fourth digits--except that to make the turbine sensors a redundant group (requiring at least one active sensor in the group above the trip level AND at least one active sensor in the group above the alarm level to initiate a high vibration trip) a 1 is used for that designation.

<p>In your application, JK39R_1, the turbine group redundancy mask is D800, because the BB1 and BB2 are redundant sensors on turbine bearing number 1, and BB4 and BB4 are redundant sensors on turbine bearing number 2 (of a two-bearing unit), and there are no turbine sensors in the third- and fourth groups.

<p>In your application, JK39U_2 and JK39R_2, the utilization- and redundancy masks for the load gear group, should both be 0000 because there are no sensors used on the load gear and no redundant sensors on the load gear.

<p>In you application, JK39U_3, the generator group utilization mask is 0070, because BB10, BB1, and BB12 are used. That would be 0 for the first hex digit, 0 for the second hex digit, 4+2+1=7=7 Hex for the third hex digit, and 0 for the fourth hex digit. Because a 0 was used for the fourth digit, any active sensor in the group above the trip level will initiate a high vibration trip--i.e., it is a non-redundant group.

<p>In your application, JK39R_3, the generator group redundancy mask should be 0060, because BB10 and BB11 are redundant sensors on the turbine-end generator bearing; that would be 0 for the first- and second hex digits, 2+4=6=6 Hex for the third hex digit, and 0 for the fourth hex digit.

<p>In your application, JK39U_4 and JK39R_4, the utilization- and redundancy masks for the "other" group, should both be 0000 because there are no "other" sensors used and no redundant "other" sensors.

<p>The unit(s) at your site do not appear to be GE-built. Units built under license from GE by 'manufacturing-' or 'business associates' were under no obligation to use the Control Specification documents that GE used--unfortunately. If the MAs/BAs had, you would have more information and it would be consistent with the information provided in the Control Specifications for GE-built units. This would make discussing and comparing units easier.

<p>And, if wishes were nickels, this author would be a very, very wealthy individual....

markvguy