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Section 2: Technical Specification for Turbines, Governors, Main Inlet Valves and associated auxiliaries
Sr.No. Clause Comments of SJVN Replies after receipt from WAPCOS
1. 2.1.1&
2.23 (D) to (H)
Separate TS sections have been
envisaged for Butter fly valve, cooling
water system, LP air system and
Drainage & Dewatering system. Even
then items of above system have been
incorporated in this scope. Contradiction
shall be clarified.
Wapcos has agreed with SJVN,
thereby accepted
2. 2.2.1.3 Selection of Turbine capacity as
225000.0 KW at a design head of 287.0m
may be clarified. In our opinion, turbine
output has to be more that above value at
this head.
Accepted
3. 2.2.2.1 Supporting documents for selecting
inertia constant (H) as 4 MW/MVA shall
be submitted.
Accepted
4. 2.2.2.2 The figure of 356 does not have any
unit, clarification & supporting document
shall be submitted in this regard.
Wapcos has submitted the
maximum momentary pressure as
387mWC. In our understanding, it
shall be 356mWC (879.75-
525=355mWC). Please clarify.
5. 2.2.2.6 The supporting document for selecting
minimum weighted average efficiency as
94% shall be submitted.
Not accepted. As per CEA
guideline for Best practices “The
minimum weighted average
efficiency obtainable for Reaction
turbine is 95%”.
6. 2.2.2.7 (III) (b) & (c)
The 343.43m3/sec is rated discharge
corresponding to rated output ( 900MW)
of plant as per DPR whereas in this
clause it has been considered as running
of 4 machine with 10% overload at FRL.
The contradiction shall be clarified.
Not agreed. The comment was that
with 10% overload, the discharge
would increase. The increased
discharge should be specified here.
7. 2.2.2.7 (III) (c) It is not understood how tail race water
level corresponding to 466.0 m3 will be
lower than 343.43 m3 and from where
this discharge of 466.0 m3 has been
considered.
The clarification is needed for above.
Ok. Row may be deleted.
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8. 2.2.2.8 Purpose of Incorporating this clause shall
be clarified & justified as power house
dimensioning and equipment layout
planning has been carried out with
machine speed of 250 RPM only.
Ok. The clause may be deleted.
9. 2.2.3 Approved DPR envisaged the hard
coating for susceptible under water
components whereas no such provision is
made in the specification. The reason for
same shall be provided.
No hard coating has been proposed
in this clause. Kindly check the
same and include the details of hard
coating in the clause.
10. 2.2.3.1 Section-I does not cover any details in
respect of Petrographic analysis and
chemical analysis of water as referred in
this clause. Same shall be clarified.
Ok. Please include the same in the
Section-I
11. 2.2.4.1 & 2.2.4.2 (a)
If turbine give output of 228426.40kW at
a design head of 287.0 m at 100% Guide
vane opening then how Turbine will
produce 110% output . Same shall be
clarify.
Not agreed. The clause may be
modified as following:
The following turbine outputs and
efficiencies shall be guaranteed by
the bidders in their bids
a) 228426.40kW output at the
design net head of 287 m and
less than 100% guide vane
opening for 100% generator
output.
b) One hundred and ten percent
(110%) output of generator at
100% (full) guide vane opening
at the minimum (rated) head.
c) Turbine efficiencies at 110%,
100%, 90%, 80%, 75% and
70% of the rated turbine
outputs at various listed net
heads in the specified working
head range. At lower
percentage of rated outputs viz
from 50% to 20% the value of
expected efficiencies shall be
stated in the bids.
12. 2.2.4.2 Criteria for selecting 2% as difference in Relevant clause of other projects
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efficiency between maximum efficiency
and that at rated output & rated head
shall be submitted..
may be submitted along with.
13. 2.2.4.3 (1) Criteria (standard, norms, benchmarks etc.) for choosing this formula for weighted average efficiency shall be submitted.
Accepted.
14. 2.2.4.4 (4) Supporting documents for choosing penalties values specified in clause for shortfall of Output and weighted average efficiency shall be submitted.
Accepted
15. 2.2.4.4 (7) Criteria for selecting rejection limit value as 2% or more needs to be supplied.
Relevant clause of other projects may be submitted along with.
16. 2.2.5.1 Safe operating zone for machine in the cavitation as well as non cavitation zone shall be clearly specified in the specification.
It is requested to supply a copy of IEC 60194
17. 2.2.5.3 Supporting documents for limiting the speed rise limit of 45% shall be provided.
Please cross check the relevant documents since as per IS 12837, the speed rise limit has been set from 35 % to 55 %.
18. 2.2.5.4 (1) Seismic force considered in Section –I as
per clause 1.8.7.1 are 0.33g for
Horizontal and 0.22g for Vertical whereas
it is different as per this clause. The
contradiction of values shall be clarified.
Ok. The base document may also
be specified).
19. 2.2.6.8 (3) Justification for incorporating this clause may be clarified with benchmark documents or other guideline documents.
Not agreed. Please submit the relevant documents as per latest guidelines issued by Govt. of India
20. 2.3.2.4 & 2.3.2.5
Calculation document for considering static pressure as 320.0mWC and Transient pressure rise as 430.5 m shall be submitted.
Please submit the document for transient pressure rise of 430.5 cumecs
21. 2.3.6.1 Justification for selecting Materials, manufacturing method etc. for different component of Turbine shall be provided with their merits/demerits.
Supporting document not attached
22. 2.3.6.1.2 Analysis document with merit & demerits shall be provided for selecting material and manufacturing methodology for Runner so that suitability at Arun-III HEP shall be ensured.
Supporting document not attached
23. 2..4.13..1 Supporting documents for limiting the runaway speed test period as two (2) minutes shall be provided.
Not agreed. The period for runaway speed test has to be provided in the specification or minimum of CEA guidelines has to be adhered to.
24. 2.5.3.1 (i) Reason for selecting wicket gate closing time range from 0-20 seconds shall be supplied. It is understood that being a hydro-mechanical item closing of wicket gate in 0 seconds is impossible.
Range to be supplied along with supporting document.
25. 2.6.1.2 287.0m is design head for the machine, whereas static head corresponding to
Ok. To be incorporated in technical specification.
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FRL & M/c Centre line is higher (845-525 = 320m), Therefore, discrepancy in the value shall be clarified as it will impact the design of MIV.
26. 2.6.2 (A) (iii) to (ix)
Justification of calculations for selecting the listed parameters in this clause shall be provided.
Please the calculations along with the relevant documents for all the calculations for above values.
27. 2.6.2 (B) (i) Justification documents shall be submitted for selecting the design of MIV opening under differential pressure of 50%.
Kindly submit the supporting document along with relevant standard.
28. 2.6.2 (B) (i) & (ii)
Criteria (standard, norms, benchmarks etc.) for choosing opening and closing time range as 60-120 sec shall be submitted.
Kindly submit the supporting document along with relevant standard.
29. 2.6.2 (C) Section-I does not cover any such details as referred in this clause. Same shall be clarified.
Ok. Please include the same in the Section-I
30. 2.6.2 (D) Seismic force considered in Section –I as
per clause 1.8.7.1 are 0.33g for
Horizontal and 0.22g for Vertical whereas
it is different as per this clause. The
contradiction of values shall be clarified.
To be changed.
31. 2.6.5.1 (d) The calculation in respect of maximum hydrostatic pressure of 534mWC shall be submitted.
There is no clause 2.6.2.8. Kindly submit the calculations for the same.
32. 2.6.5.16 Justification for selecting Ultrasonic flow detector shall be provided as winter Kennedy type flow meter is also proposed in clause 2.9.1.
Both methods provide for flow measurement (one equipment to be provided only)
33. 2.7.1 Justification for selecting separate OPU system of Turbine and MIV shall be submitted
Not agreed. . Documents of similar project to be provided.
34. 2.7.7 The guide vane control through head is not considered in governor as per clause 2.5.3 whereas it has been described in this clause. Contradiction in this regard shall be clarified.
Ok. Same shall be incorporated.
35.2.14.1
The supporting document shall be submitted for proposing the various kind of test to be performed for Turbine equipment’s.
The question relates to the supporting documents for the necessity of tests to be included in the TS. Kindly provide the relevant supporting document.
36. 2.16 It is not clear from this clause whether Field acceptance test for performance and efficiency in respect of guaranteed figure to be performed on one unit or all unit. Same shall be clarified and elaborated.
Ok. Same shall be incorporated in the TS
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