turbine protection test u4

Unit 4 AOH Turbine Protection Test

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Morupule B Power Station

4 × 150 MW Coal-Fired Power Plant

Palapye, Botswana

Turbine Protection Test:

Unit 4 Annual Overhaul 2015

TEST DATE: 23/12/2015 TO 31/12/2016


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1. Test of EH oil pressure Protection

Condition

The protection is initiated, if

2oo3 of the EH oil pressures < 7.8 Mpa.

Alarm value: <11.2 Mpa.

Test method

1. Ensure the cables connected between the f ield instrument and control cabinet are correct

according to the design drawings.

2. Check the setting value in the calibration certificate for the pressure switch is correct.

3. Disconnect the connection of pressure switch.

4. Do the test in three groups: 1&2, 1&3, 2&3. It will also be test that only one signal will not

trip the turbine.

5. Confirm the protection is active.

6. After each test normalize the system and acknowledge/clear all alarms and protections on

the HMI.

Results

Protection tested and OK

2. Test of Lubricate oil pressure Protection

Condition


2oo3 of the lubricate oil pressures <0.0392 Mpa.

Alarm Value: <0.04 Mpa.

Test method






trip the turbine.



the HMI.

Results



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3. Test of condenser vacuum pressure Protection

Condition


2oo3 of the condenser vacuum pressures <0.05 Mpa.

Alarm Value: <0.055 Mpa.

Test method






trip the turbine.



the HMI.

Results

Bridged instead of disconnecting all three switches to activate trip. They should be opened to

activate trip. Therefore the protection is wired as a NO contact instead of an NC contact. To be

discussed with the project team as all protections must be wired as NC contacts.

However the protections tripped the turbine on 2oo3 logic.

4. Test of Lubricate oil level Protection

Condition


2oo3 of the lubricate level < - 180mm.

Alarm Value: < - 230 mm.

Test method



2. Check the setting value in the calibration certificate for the level switch is correct.

3. Disconnect the connection of level switch.

4. Short circuit two wires of the cable to simulate the active signal of level switch.


trip the turbine.



the HMI.


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Results

Protection is in service but NO contact used instead of NC. To be discussed with CNEEC

5. Test of Remote Manual Trip PB Protection

Condition


Two manual trip press buttons are pressed simultaneously.

Test method

1. Ensure the cables connected between the press buttons and control cabinet are correct


2. Simulate the ETS, DEH do not work when they got the input signals.

3. Press the single button separately.

4. Confirm the protection is not active.

5. Press the two buttons simultaneously.



the HMI.

Results


6. Test of Bearing Metal Temperature Protection

Condition


1oo26 of the Bearing temperature > 115 ºC.

Alarm Value: > 105 ºC.

Test method



2. Simulate thermocouple temperature signal by the simulator one by one in turn at field. First

to TEMP H > setting value and confirm the alarm. Then to TEMP HH > setting value and

confirm the protection is active.


the HMI.

Results


5

Protection tested and is OK

7. Test of MFT Trip Protection

Condition


1oo2 of boiler MFT trip.

Test method

1. Ensure the cables connected between the MFT controller and control cabinet are correct


2. Disconnect one of the wires between ETS and MFT, trigger the MFT trip and confirm the

protection of turbine is active.

3. Test the other connection between ETS and MFT and confirm the protection of turbine is

active as 2.


the HMI.

Results


8. Test of Generator Trip Protection

Condition


1oo1 of Generator trip.

Test method

1. Ensure the cables connected between the MFT controller and control cabinet are correct


2. Trigger the Generator trip and confirm the protection of turbine is active.


the HMI.

Results


9. Test of Over speed Protection

Condition


2oo3 of the turbine speed >3300 Rpm.

Alarm Value: >3024 Rpm.


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Test method



2. Force the speed of turbine above 3300 Rpm in TSI cabinet, confirm the protection is active.

3. Test the three channels separately.


the HMI.

Results

Checked the TSI over speed modules and they were set as follows: OS1 3300 rpm, OS2 = 3250rpm

and OS3 = 3250 rpm. Module settings should all be 3300 rpm hence OS2 and OS3 were changed

to 3300 rpm.

The test cannot be implemented as specified in the procedure, more information is required from

CNEEC. A programmer was used to link to the Epro module to extract information on settings.

10. Test of Rotor Trust Position Protection.

Condition


1oo2 of the rotor position <(or >) Turbine end -1.65

Generator end +1.2

Alarm values: Turbine end -1.05

Generator end +0.6

Test method



2. Check the sensor calibration certif icate from the sensor manufacturer.

3. Disconnect the connection between the field instrument and control cabinet. Connect the

unit of test sensor and proximitor within the field junction box.

4. Simulate rotor position signal by moving the test sensor one by one in turn on f ield side.

First to POSI H (positive and negative) > setting value and confirm the alarm. Then to POSI

HH (positive and negative)> setting value and confirm the protection is active.


the HMI.

Results

All rotor thrust position settings checked and are set according to specification in the turbine test

procedure.




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11. Test of Differential Expansion Protection

Condition


1oo2 of Differential Expansion < (or >) the setting value.

HP Cylinder:

Positive expansion + 6.2 mm.

Alarm value: + 6 mm.

Negative expansion - 3.2 mm.

Alarm value: - 3 mm.

LP Cylinder:

Positive expansion: + 8 mm.

Alarm value: + 7.8 mm.

Test method







First to POSI H (positive and negative) > setting value and confirm the alarm. Then to POSI



the HMI.

Results

All differential expansion settings were checked and the HP cylinder negative expansion trip value

was found to be 3.175 mm instead of 3.2 in the test procedure. This was however not changed.

The LP cylinder positive expansion trip value was found as 8.2 mm but the test procedure specified

8.0 mm, the alarm value was found to be 8.0 in the module but in the test procedure it is specified

as 7.8 mm. This was also left unchanged

The test procedure does not specify the negative expansion trip and alarm values however in the

Epro module they are set to -6.0 mm for both the trip and alarm values.




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12. Test of Bearing Shaft Vibration Protection

Condition


1oo10 of Bearing Shaft Vibration > 0.250.

Alarm value: > 0.127.

Test method







First to POS H (positive and negative) > setting value and confirm the alarm. Then to POS



the HMI.

Results

The bearing shaft vibration settings were verified in the respective modules for both x and y

vibrations and they are set in accordance with the test procedure.



13. Test of DEH Trip Protection

Condition


1oo5 of DEH trip condition is active.

Test method



2. Test the hardwire and software separately.

3. Test the f ive condition for DEH trip protection one by one as per the following steps:

a) Shut down the DC power in the DEH cabinet, confirm the protection is active.

b) By pressing the PB in the DEH system, confirm the protection is active also.

c) By removing the speed card to simulate the BDQ of speed sensor, confirm the

protection is active. (2oo3) 1&2, 2&3, 1&3.

d) Disconnect the wires of speed sensor in the field junction box. Simulate the speed

sensor frequency signal with the simulator. Confirm that the protection is active.


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Results

a. The 3a protection in the above test method was tested and is OK

b. The 3b protection in the above test method was not found. CNEEC to elaborate further

c. On conducting the 3c protection the speed cards IMFCS01 were the ones removed from

their racks. When the first speed card is removed, ‘DEH speed 1 fail alarm’ is shown. On

removing the second module no alarm came up and removing the 3rd one also gave no

alarm. The turbine failed to trip with all modules removed. But when all the modules are

inserted back, then the turbine trips. This result does not align with the expectations of the

test procedure because the turbine should trip when two of the speed cards are removed

not when they are inserted back. CNEEC will be contacted for further clarity since there

could be other setting required for the test to behave as specified.

d. Speed sensor frequency signal simulation was not done as the test procedure was not clear

on how this was to be conducted. CNEEC also contacted regarding this test and they will

give clarity.

Conclusion

For a first out and alarm analysis as the protections tripped the turbine please refer to the

Turbine Protection Results Excel sheet.

Tests carried out by: Tshenolo Odisitse - IMD

Blessing Sebinyane - IMD

Witnessed by: Masego Otlogile - IMD

Galebolwe Gabadirwe – Operations Department

Chasiwe Omphemetse – Operations Department

turbine protection test u4

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