2 Mariakani 400/220kV Substation
This tender addendum and clarification forms part of the Request for Proposal and Contract documents, and modifies them as follows:
I. CLARIFICATIONS
S.No. Clause/Paragraph/Item No. Clarification/Query Response
2 Bid data sheet (Commercial)
In the bid data sheet of Volume I, the name of the project is: Mombasa Nairobi Transmission Line Project, but the name of the bidding process is Construction of Mariakani 400/220kV Substation. Please clarify which one is the Contract Name required in the Form – Bank Guarantee
Project Name is Mombasa – Nairobi Transmission Project - 400/220kV Mariakani Substation
3 Volume 2 Appendix A (Drawings)
Kindly confirm the Appendix A – Bid drawings in Volume 2, the drawings should be provided but actually are not
Please refer to the attached Drawings listed below-: PB-KET-2012-D-223 Mariakani 220kV Single Line Diagram
PB-KET-2012-D-224 Mariakani 400kV Single Line Diagram
PB-KET-2012-L-234 Mariakani 220kV Layout
PB-KET-2012-L-235 Mariakani 220kV Elevations
PB-KET-2012-P-287 Mariakani 400/220kV Substation SCS Single Line Diagram
PB-KET-2012-P-288 Mariakani 400/220kV Substation LVAC Single Line Diagram
PB-KET-2012-P-289 Mariakani 400/220kV Substation 110V DC Single Line Diagram
PB-KET-2012-L-201 400kV Double Tension H/Ware fittings for Quad ACSR Lark
Conductor
PB-KET-2012-L-203 Tension clamp with Al encasing suitable for ACS Earthwire
(7/3.26)
3 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response PB-KET-2012-L-205 Jumper Spacer for ACSR Lark Conductor (400kV)
PB-KET-2012-L-206 Single Suspension (Pilot) H/Ware fittings for Single ACSR Canary
Conductor (220kV)
PB-KET-2012-L-207 Quad Spacer Damper for ACSR Lark Conductor (400kV)
PB-KET-2012-L-208 400kV Pilot Suspension H/Ware fittings suitable for ACSR Quad
Lark Conductor
PB-KET-2012-L-209 Single Tension H/Ware fittings for Single ACSR Canary Conductor
(220kV)
PB-KET-2012-L-217 Double dead end set passing for OPGW cable diameter 19.6 –
20.6mm - 28110225 (F-0887)
PB-KET-2012-L-218 Single dead end set for OPGW cable diameter 19.6 – 20.6mm –
28110224 (F-0886)
PB-KET-2012-L-219 Tower Hinge for double tension hardware fittings suitable for
quad ACSR lark conductor (400kV)
6861162 Confirmed Outline Drawing (Shunt Reactor)
182AKPDE2006A Clearance diagram for Existing 220kV Tower- to be dismantled
182AKPDE2006A Clearance diagram for Existing 220kV Terminal Tower
182AKPDE40010 Clearance diagram for Existing 400kV Terminal Tower
SDH-1/2- Single Unit Staff Housing for senior staff (Annex 21.5 .1)
DDH-2/2- Double Unit Staff Housing for sub-ordinate staff (Annex 21.5.2)
4 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response 1KHD636398 Sheet 504 Telecommunication System - System Layouts Legend
1KHD636398 Sheet 500 Telecommunication System – Western Region
1KHD636398 Sheet 501 Telecommunication System – Mount Kenya Region
1KHD636398 Sheet 502 Telecommunication System – Coastal Region
1KHD636398 Sheet 503 Telecommunication System – Nairobi Region
1KSE 000 535D410 Sheet 1 to 9 Block Diagram Network Manager
PB-KET-2012-D-233 Mariakani Overall Layout
PB-KET-2012-D-236 Mariakani 400kV Layout
PB-KET-2012-L-237 Mariakani 400kV Elevations
PB-KET-2012-P-280 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 1
PB-KET-2012-P-281 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 2
PB-KET-2012-P-282 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 3
PB-KET-2012-P-283 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 4
PB-KET-2012-P-284 Protection Single Line Diagram – Mariakani 400/220kV Substation 220kV Diameter 1
PB-KET-2012-P-285 Protection Single Line Diagram – Mariakani 400/220kV Substation 220kV Diameter 2
PB-KET-2012-P-286 Protection Single Line Diagram – Mariakani 400/220kV Substation 220kV Diameter 3
64161A-PBP-L-0016 Mariakani Substation Layout
5 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
4 Pre-bid Schedule Approach to site: As per tender pre-bid meeting is scheduled on 3rd September, 2013 (10.00 hrs Kenyan standard time) at Nairobi and as per information received from your good office the project site i.e. Marikani is located about 400 KMs far from Nairobi city. So please inform the most suitable mode of transportation from Nairobi to Marikani site (by Air/ by Train / by Car) and the expected time to reach at the site. Will KETRACO be facilitating in arranging the local transportation?
Please refer to the Program Schedule
5 Pre-bid Schedule Programme for site visit- At what time the site visit will start? Will it be last till 3rd September only or also be extended up to 4th September. Please also provide the contact details of official/s who might be accompanying the bidder’s team for site visit. We would also like to request KETRACO to arrange a meeting with reputed local civil contractors/ Erection agencies/ Logistics agencies / vendors for local purchase, if any.
Please refer to Clarification no. 4 KETRACO shall not arrange any such meeting.
6 Pre-bid Schedule Also inform the hotels available in Nairobi City & near Marikani project site (in the range of USD 80-90 per day).
Please refer to Clarification no. 4
7
Volume 2 Appendix A (Drawings)
Please also arrange to send the tender drawings ( layout & single line diagram) as the same are not available with the tender documents uploaded
Please refer to Clarification no.3
6 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
on site.
8 Section I, paragraph 4. Eligible Bidders, point 4.2 (Commercial) Section V – Eligible Countries; particulary section A, point 1.6 (Commercial)
Section I, paragraph 4. Eligible Bidders, point 4.2 A Bidder, and all parties constituting the Bidder, shall have the nationality of an eligible country, in accordance with the Bank’s Rules and Procedures for Procurement of Goods and Works, and as listed in Section V, Eligible Countries.8 A Bidder shall be deemed to have the nationality of a country if the Bidder is a citizen or is constituted, incorporated, or registered and operates in conformity with the provisions of the laws of that country. This criterion shall also apply to the determination of the nationality of proposed subcontractors or suppliers for any part of the Contract including Related Services. Section V – Eligible Countries; particulary section A, point 1.6 1.6 The African Development Fund permits firms and individuals from all countries to offer goods, works and services for ADF funded projects. However, the proceeds of any Financing undertaken in the operations of the African Development Bank and the Nigeria Trust Fund shall be used for procurement of goods and works, including the related services, provided by bidders from Eligible13 Countries.14 Any conditions for participation shall be limited to those that are essential to ensure the firm’s capability to fulfill the contract in question. In the
The African Development Fund permits firms and individuals from all countries to offer goods, works and services for ADF funded projects. For a list of debarred firms refer to: http://www.afdb.org/en/projects-and-operations/procurement/debarment-and-sanctions-procedures/
7 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
case of ADB and NTF, bidders from non-Member Countries offering goods, works and related services (including transportation and insurance) are not eligible even if they offer these from Eligible Member Countries. Any waiver to this rule will be in accordance with the Articles 17(1) (d) of the Agreement Establishing the African Development Bank and 4.1 of the Agreement Establishing the Nigeria Trust Fund. From above mentioned it is not clear to
us if this tender is open to the bidders
from all countries, as this tender is
financed by the African Development
Fund and, as per section V, African
Development Fund permits firms and
individuals from all countries to offer
goods, works and services for ADF
funded projects or this tender is open
only to the bidders from the countries
that are members of the African
Development Bank.
Question: Please confirm that Croatia
is Eligible Country.
9 Volume 2 Appendix A (Drawings)
From Page 364 of Volume 2 Appendix A, it
mentioned “The following drawings are provided
with this bid document”. Pls refer the annex.
Please refer to Clarification no.3
8 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
Volume 2 Appendix B (Drawings)
The problem is we can’t find the drawing in the
bid document, the same for the Appendix B
“Existing Telecommunications and OPGW
System”. Please advise if the diagrams are in the
hard copy?
10 Volume 2 Appendix A and Appendix B (Drawings)
Appendix A – Bid drawings & Appendix B- Existing
Telcom and OPGW are missing.
Please refer to Clarification no.3
11 Volume 2 Appendix A (Drawings)
We have noticed that the drawings “Appendix A”
of the Employer’s requirements are not included
in the package received. Could you please send
us the drawings so that our technical team can
start working promptly.
In addition, I would like to know the agenda of
the pre bid meeting. As the site is near Mombasa,
do you plan to have the site visit the same day ?
What is the organization ?
Please refer to Clarification no.3 Please refer to Clarification no. 4
12 Technical Specifications, Section 1.2.1 (Technical)
Tender Drawings and Scope of Works
From the Section 1.2.1 Mariakani 400/220kV
Substation in the Technical Specifications, it has
mentioned that the scope of work consists of six
partially equipped breaker-and-a-half scheme
diameters for the 400kV substation. However, in
the invitation to bid, mentioned scope of only
This has been corrected in this TAC Item 1.2.1 below
9 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
Volume 2 Appendix A, Appendix B (Drawings)
four diameters. Kindly clarify the scope.
Furthermore, it is mentioned in Appendix A and B
a list of drawings related to the tender, however
these are not attached to the documents. We
kindly request these drawings to be provided to
give clarity to the scope.
Please refer to Clarification no. 3
13 Technical Specifications, (Technical)
Shunt Reactor Dimension Drawings
From the scope of works, it is mentioned that we
must install Line Shunt Reactors that are from the
Rabai SS to Mariakani SS. In order for us to
consider dimensions of foundations and space in
Mariakani, kindly provide us the “Dimensional
Drawings” of the existing Shunt Reactors which
shall show the physical dimensions and weight of
the reactor.
Furthermore, we would like to inquire if
transport of the Shunt Reactors from Rabai to
Mariakani shall also be part of this Tender Scope.
Please refer to Clarification no. 3 Shunt reactor transportation is part of the scope.
14 Technical Specifications / Technical Data Schedule (Technical)
Transformer Capacity Requirement
We notice as follows:
Invitation to bid shows – 200MVA Transformers
The 400/220kV autotransformers shall be 200MVA rated.
10 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
Technical Specification shows – 200 MVA, 3-
phase Autotransformer or 66.6 MVA 1-phase
Transformer (1.3 of the overall MVA)
Technical Data Schedule shows – 500 MVA
Transformers
We kindly ask for a clarification on the required
rating of the Transformers.
15 Submission Date Extension (Commercial)
Tender Submission Extension
In view of the above questions, we find that the
submission date on the 11th October shall be tight
for us to meet and we will need more time for
preparation of a comprehensive bid. We kindly
ask for your consideration to extend the
submission date to four (4) weeks.
Please refer to TAC 1 Clarification no. 1
16 General
Bid drawings listed in Appendix -A is not received.
Please furnish the same.
Please refer to Clarification no. 3
17 Technical Specification for
substation & OHL Termination -
Section VI. Clause no: 1.2.1
The 220kV substation’s configuration is a
‘breaker-and –a –third’ however the numbers of
bays are not clear in scope, hence please provide
the requirement of 220kV system.
Please refer to Clarification no. 3
18
General
We presume that the switchyard equipments,
earthing, lightning protection, main bus bars,
lighting cable, AC & DC auxiliary system shall be
considered only for the present scope. We have
not considered for the same for the future scope.
Please refer to Pre-bid meeting minutes page 3 under comments by the Consultant (Allan Burns) paragraph 7. The 48V DC shall have 50% extra capacity for future (refer 9.4.3.1 of the Technical Specification) and the 110V DC shall have 30% extra capacity for future (refer 11.3.2.2 of the Technical Specification). The AC auxiliary system shall
11 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
Please confirm. be constructed now for all future diameters (refer 11.1 of the Technical Specification). Also refer to this TAC Item 1.2.1 below
19 Technical Specification for
substation & OHL Termination -
Section VI. Clause no: 19
Technical specification indicates that the 11kV
cable connections need to be provided, however
the scope of 11kV cables are not clear, please
provide the same.
Please refer to this TAC Item 1.2.1. 11kV cable below. Requirements are left to the bidders discretion but shall conform to IEC Standards. Also refer to this TAC additional statement covering Item 21.1.1 below
20 Technical Specification for
substation & OHL Termination -
Section VI.
Existing Telecommunication system and OPGW
system drawings as listed in appendix- B is not
received. Please furnish the same.
Please refer to Clarification no. 3 drawings no.: 1KHD636398 Sheet 504; 1KHD636398 Sheet 500; 1KHD636398 Sheet 501;1KHD636398 Sheet 502; 1KHD636398 Sheet 503
21 General Please provide the soil resistivity of Mariakani SS. There is no soil investigations report. Refer to Site Visit Notes under Mariakani site visit to proposed substation site: paragraph 4
22 General Please provide the SAS architecture drawings. Please refer to Clarification no. 3
23 Technical Specification for
substation & OHL Termination -
Section VI.
Please clarify whether the DG sets shall be Indoor
type or outdoor type. Also please clarify whether
separate DG set room is to be provided.
Diesel generator set to meet the specification requirements in the
Technical Specification for substation & OHL Termination under
Clause 20. The Generator will be located in a separate building
complete with fire protection. The rating shall be, as a minimum
1MVA. The actual rating of the generator proposed by the bidder
shall ensure the generator is able to power the entire control building,
switchyard lighting and street lighting, and suitable for the ultimate
design of the Mariakani substation.
24 Technical Specification for
substation & OHL Termination -
Section VI. Clause no:20.
Please furnish the Current rating, ratio, class,
burden & number of cores for 400kV & 220kV
current transformer & capacitive voltage
transformer.
Please refer to Clarification no. 3 drawing no.: PB-KET-2012-P-280; PB-KET-2012-P-281; PB-KET-2012-P-282; PB-KET-2012-P-283; PB-KET-2012-P-284; PB-KET-2012-P-285; PB-KET-2012-P-286
25 Technical Specification for The rated current in the Technical data sheet is The 4000A and 2000A ratings are the ratings of the respective air
12 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
substation & OHL Termination -
Section VI. Technical
schedules(General):-
Clause no: 1.10 & Clause no:1.9
indicated as 4000A for 400kV & 2000A for 220kV.
We presume that there are busbar rating. Please
confirm.
Also please furnish the equipment rating for
400kV & 220kV circuit breakers and
disconnectors.
insulated switchgear.
The respective air insulated equipment rating (including circuit
breakers) is stated with Section A. “1. General” of the Technical
Schedules.
26 Technical Specification for
substation & OHL Termination -
Section VI. Clause no:1.2.1 &
Technical schedule(Power
Transformer):- Clause no:1.20 &
1.21
The Power Transformer rating shown as 200MVA
in the clause no: 1.2.1 , whereas in Technical data
sheets(400/220kV Power transformer)the MVA
rating is shown as 500/√3 MVA/ 300/√3 MVA.
Hence please clarify& confirm the Transformer's
rating.
The IBT is required as a three phase unit with a MVA rating of 200MVA.
27 Technical Specification for
substation & OHL Termination -
Section VI. Clause no:21.5.1
Please furnish the Annexure 21.5.1& Annexure
21.5.2. for Staff housing .
Please refer to Clarification no. 3 drawings no.: SDH-1/2 (Annex 21.5 .1); DDH-2/2 (Annex 21.5.2).
28 Technical Specification for
substation & OHL Termination -
Section VI. Clause no: 22
As per specification ACSR Lark conductor is
specified for 400kV and ACSR Canery for 220kV
Transmission line. Please clarify whether can use
the same type of conductor for Substation also.
ACSR Lark conductor or ACSR Canery may be used for substation conductors provided the design meets clause 3.3.1 of the Technical Specification and the required rating of 4000A and 2000A for the 400kV and 220kV switchyards respectively.
29 Technical Specification for
substation & OHL Termination -
Section VI. Clause no: 8.2.1.1
Please confirm that whether the existing
Protection relay panel for reactor in Rabai SS can
be shifted to Mariakani.
The existing shunt reactor panel shall be decommissioned under this work scope with a new panel required within the Mariakani substation scope. Refer to Site Visit Notes under Rabai Site visit to view Shunt Reactor: paragraph 3.
30 Technical Specification for
substation & OHL Termination -
Section VI. Clause no: 21.5.2
Kindly provide the height of the store which is to
be provided.
The height of the store room shall be sufficient to accommodate all spares. As a minimum the store height shall be not less than 5m.
13 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
Store
31 Technical Specification for
substation & OHL Termination -
Section VI. Clause no: 21.7.1
Topographical Survey and
details
Kindly provide the approximate distance between
the existing ground level and the proposed
finished ground level inorder to assess the depth
of foundation.
There is no topographic survey report. Bidders were taken to site and all topographic aspects shall be at the bidders risk.
32 General
Kindly provide the finished ground level for the
substations.
The Contractor shall design this based on ground conditions.
33 General
Kindly provide the out fall point for storm water
drains.
Refer to this TAC Additional Statement covering Item no. 21.17.12 below
34
General
Kindly clarify whether the substation shall be
made in multiple levels in case needed to reduce
the filling/cutting quantities.
NO. There will be no multiple levels.
35 General
Kindly provide the High Floor level for fixing the
Finished Ground Level.
Refer to Clarification No. 32
36
General Kindly provide the location for construction of
the staff housing units for the substation.
Housing location is at bidders’ discretion but shall be submitted for approval. It shall be within the Ketraco’s site boundary, not under the transmission line and not a hindrance to the construction or operation of the substation.
37 Technical Specification for
substation & OHL Termination -
Section VI.
Generator rating, capacity & type (with canopy or without canopy).
Refer to Clarification No. 23
14 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
38
SLD & Electrical layout of proposed substation (Mariakani 400/220 kV substation)
Refer to Clarification No. 3
39
Details of civil drawings of control room building,
Koisk, Guard room & other required residential &
office accommodation
Floor area for the control room building and no. of rooms shall be designed by the contractor to meet the requirements of the Technical Specification based on three 400kV diameters, four IBT’s and three 220kV diameters and allow space for future panels. Civil design shall meet the Employer’s Requirements- other details at the discretion of the bidder. For the Layout Drawings of residential houses, refer to the attached Tender Drawing
40
Bid documents Appendix A & B provides for drawing list & existing telecommunication/ OPGW Systems & in clarifications it is stated that drawing shall be provided during pre-bid meeting. Please arrange to provide drawing and details along with soft copy.
Please refer to Clarification no. 3
41
In BOQ( Item No 8. Schedule-1), it provides for 220kv buried cable with accessories, but quantity shown as zero. Similarly item no 13 & 16 for 220 KV Line & 400 KV Line respectively, has been shown as zero. It is presumed that Zero items are not covered in the present scope of Supply. It need to be confirmed that all Zero items in BOQ are not covered in present scope & need not to quote by bidder.
For items 13.4, 13.5, 15.1, 16.4, 16.5 and 18.1 the Estimated Quantity should be one (1). For all other zero items, do not quote.
42
In the Schedule -4 of the BOQ for installation, item no 28 provides for installation of 220 KV Buried cable with accessories, but shown as zero. Item no 28.9 to 28.17, site clearance, leveling, soil
For items 35.4, 35.5, 37.1, 38.4, 38.5 and 40.1 the Estimated Quantity should be one (1). For all other zero items, do not quote.
15 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
investigation/testing, survey, grading road crossing etc has been provided but quantity shown is zero. Site clearance. Similarly item no 35 &38 shown as zero. It need to be confirmed that all Zero items in BOQ in services , are not covered in present scope & need not to quote by bidder.
43
Item no 28.14 of Schedule -4 , Provides for trenches , excavation etc for existing services and shown as Zero. If is it considered as not in present scope as per above point, than please clarify, where is the provision for trenches for new substation in the BOQ, and provision for trenches for new substation need to be provided in the schedule-4
Refer to the updated price schedule within this TAC below. Trenches are stated within Section 30.45 of Schedule No.4.
44
Earthing type A, B, C for towers has been provided in BOQ, its details / drawing need to be provided.
Item 19 of Price Schedule No. 1. “Counterpoise Cable (220kV and
400kV Line)” is not required and shall be removed from the Price
Schedule No. 1.
Item 41 of Price Schedule No. 4. “Counterpoise Cable (220kV and 400kV Line)” is not required and shall be removed from the Price Schedule No. 4.
45
Tentative distance of IBT to Auxiliary –x- former may be provided.
To be based on the Bidder’s designs
46
Staff quarter/ store layout plan / drawing need to be provided; otherwise there will be ambiguity between bid submissions.
Refer to Clarification No.3 The store layout plan at Bidders discretion and also refer to Clarification S. No 30
16 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
47
Please confirm, if valid type test report is available for main equipment I.e Transformers, Switch gears, is there is any requirement to re conduct the Type test at the time of Supply. In the technical specifications (volume-2), for most of equipment it is mentioned that type test need to be conducted, if such a case there is no provision / schedule for type test charges. This need confirmation / clarity
Type tests are required to meet the Employer’s Requirement. If a type test certificate is valid and meets Employer’s Requirements then no additional type test is required.
48
In outside trenches, trays are required or not on the cable racks. Same may also be confirmed for control room trenches also.
Refer to this TAC for addendum that updates Section 11 of the Technical Specification with 11.6 LV Cables, 11.7 Low Voltage Power Cables and 11.8 Inspection and Tests particular 11.7.3 for installation requirements below.
49
Volume -2 , para 4.2.2.1 provides for Gas handling & storage unit. Please provide clarification whether it is evacuation & gas filling device, or gas handling with storage unit.
Refer to volume 2 clause 4.2.2.1 and volume 1 Schedules item 12.9
50
The main Protection at Isinya 1 &2 , their make and type of protection details may be provided for matching with new substation protection.
The bidder to provide Main Protection 1 & 2 which meets Employer’s Requirements
51
It is stated houses to the KETRACO Staff to be fully furnished, with provision of AC, furnishing details need to be provided for room wise including AC.
Please refer to Clarification no.3
52 Substation / line towers need to be type tested or not.
Line tower type tests not required
17 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
53
In the Bidding documents have two ICB No. One
on the cover of the tender documents is
KETRACO/PT/012/2013 and another in the BDS is
KETRACO/PT/012/2012. Please clarify it.
Correct ICB no is KETRACO/PT/012/2013
54
In the bidding documents ITB 13. The alternative
bids are not permitted, for technical bid, could we
provide two or three manufacture documents for
the same equipment with same technical
response in the parameter datasheet
The provision of three different manufacturers for the same equipment is not an alternative bid.
55 Please provide the outlet direction of substation Bidders were taken to site
56
Please clear the style of gantry and support struct
ures.
Gantry is lattice combined with angles, support is
lattice combined with angles or gantry is steel
tube pole, support is lattice combined with
angles.
The use of steel lattice or steel tube is at the bidders discretion (providing the Employer’s Requirements are met). To give a cost effective installation it is well known in the industry when to use steel lattice and when to use steel tube.
57
Whether the relocation of the reactor protection
devices? Please clarify it.
Could you provide the existing 400kV substation
control room panels and MK photos?
Refer to Clarification no. 29
58
Please provide the routing channel organization
between the new Mariakani substation and the
National Control Centre (NCC) and the Regional
Control Centre (RCC) respectively.
Please refer to Clarification no. 3
18 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
59
Please provide the geographical position wiring
diagram of the substation related to this project,
so that the geographical position of the
substation and the wiring length between the
substations can be seen in it.
Please refer to Clarification no. 3
60
Please provide the communication network
operation situation and the channel diagram in
where the new substation located.
Please refer to Clarification no. 3
61
Please provide the topographic map of surveying
and mapping of substation position(1:500)
Refer to Clarification no. 31
62
Please provide the scope of land can be used in
this phase.
Refer to Clarification no. 3
63
Please Confirm flood stage of 100 years, and
water logging water level of the substation.
This is the bidders responsibility
64
Please confirm the source of domestic water and
fire control station water.
Refer to this TAC that updates clause 21.11 of the Technical Specification below
65
Please provide the local substation drainage
system.
This is the bidders responsibility
66
Please provide Construction drawings of Similar
substation. (Including general layout plan, layout
plan of drainage system, gantry installation
drawings and foundation construction drawings,
equipment support installation drawings and
foundation construction drawings, cable trench
construction drawings and control house
The Mariakani substation shall be built to meet the Employer’s Requirement.
19 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
construction drawings).
67
In section II BDS, ITB 11.1(h), iii. Testing materials
and equipment in Type Test Reports shall have
the same code/ country / manufacturer and
technical parameters as offered materials and
equipment. Type tests of non-conforming
materials/equipment shall not be accepted. You
are pleased to clarify whether the test report of
the testing materials and equipment which are
high voltage or higher capacity than the offered
type can be accepted for bidding?
Type test is required for the specific equipment being installed.
68
In section VI, 1.5 Details of transmission line / HV
cable routes, The Contractor shall propose the
required modifications to the existing overhead
line to route the lines into and out of the new
Mariakani substation together with the
transmission line works required to
decommission and dismantle the existing 220kV
substation bypass. You are pleased to clarify
whether the line modification work will be done
by contractor
Section 22.1.1 of the Technical Specification states that the scope of
works includes for the provision of the overhead line entries into and
out of the substation.
Refer to Price Schedule No. 4 Item 43 for reusing disconnected conductors for rerouted connection into Mariakani substation.
69
In section II BDS, ITB16.2, The Bidder shall submit
with its bid, the Manufacturer’s Authorization for
the following part or component: 4. Composite
insulators 10. 220kV HV cable, We understand
that there is no transmission line work and 220kV
HV cable will be supplied in the contact. Whether
it will also provide the Manufacturer’s
Connection of 400kV and 220kV lines from the terminal towers to the substation is required in the scope. If the bidder’s design requires the use of 220kV cable then the Manufacturer’s Authorization for the cable would be required.
20 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
Authorization form those manufacturer?
70
Section VI, TECHNICAL
SCHEDULES
In section VI, TECHNICAL SCHEDULES, M sub-
divisions 400kV OVERHEAD LINE and N sub-
divisions 220 kV OVERHEAD LINE, You are pleased
to clarify that these Technical Schedules will not
be filled up due to there is no scope of work.
The technical Schedules in Volume 2 of 2: Supplementary Information are require to be filled in. Where the contractor is not supplying equipment when reusing the existing conductor then the respective part of the Technical Schedule shall not be filled in.
71
In section VI, Appendix A – Bid Drawings
Appendix B – Existing Telecommunications and
OPGW System, We have not found these
drawings in the bid documentation. You are
pleased to provide these drawings.
Please refer to Clarification no.3
72
For Auto transformers, the capacity is 200MVA in BOQ, but it is 500/√3 in technical schedules, which parameter is right? If 200MVA is right, is there any change for other parameters in technical schedule?
Refer to Addendum for updated Technical data sheet included within this TAC below. The IBT is required as a three phase unit with a MVA rating of 200MVA.
73
There are two different tender no. references
KETRACO/PT/012/2013 and
KETRACO/PT/012/2012. We understand that the
tender no. is KETRACO/PT/012/2013. Please
confirm
The ICB No. is KETRACO/PT/012/2013
74
We have not found appendix-A & B in tender
specification. Please provide appendix-A & B.
Please refer to Clarification no.3
75
Please provide following drawings/documents.
1. Single Line Diagram of 400/220kV SS.
Please refer to Clarification no. 3 for No. 1,2,3 and 9. The rest are the bidders responsibility
21 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
2. Layout and Section drawing. 3. Plot Plan 4. Contour map. 5. Soil Investigation report. 6. Soil resistivity report. 7. Route and details of existing transmission
line/tower. 8. Structure drawing of tower and
equipment. 9. Civil drawing of tower and equipment. 10. Drawing and finishing details of building. 11. FGL of 400/220kV Substation.
76
We are considering PVC pipe for interpole
cabling & cabling from equipment to trenches.
Please confirm.
This is acceptable practice providing it meets section 3.2.10 of the Technical Specification.
77
We are considering only space provision for
future bays only. Any work(supply, gravelling,
earthmat, foundation, tower etc) for future bays
is not in bidder’s scope.
Refer to Clarification no. 18
78
Please specify(HCB/HDB) the type of isolator. The disconnectors can be centre break or double break providing the design meets the requirements of Section 4.4.3. of the Technical Specification and the ultimate design’s spacing fits within the required layout area.
79 Please provide rating of Diesel Generator set. Refer to Clarification no. 23
80
Please specify type and rating of lumination for
indoor and outdoor illumination.
Lighting shall be suitable to meet the Employer’s requirements refer 21.18.1.2.
22 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
81
Please provide following information for
earthmat design.
1. Soil resistivity 2. Type & Size of underground conductor. 3. Depth of earthmat. 4. Type & Size of conductor for equipment
earthing
Refer to the Technical Specifications clause 3.3.1
82
Please specify type of structure(Lattice/Pipe) for
equipments.
The use of steel lattice or steel tube is at the bidders discretion (providing the Employer’s Requirements are met).
83
We have not found any list of special tools
&equipment and spare part.
Please furnish following list.
1. Spare part list. 2. Maintenance tools & tackles. 3. Erection, Installation & commissioning
tools.
The Employer shall provide an Addendum for Schedule 1: Mandatory Spares
84
Confirm that level land shall be provided for
400/220kV Substation.
Please also provide FGL of Substation.
Refer to Clarification No. 32
85
We are considering only racks in outdoor
trenches of 400/220kV Substation and in control
room for LT cable support
Refer to this TAC Clause 11.6 LV Cables (below).
23 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
86
Please provide specification of following
1. LT Power and control cable 2. Portable earthing equipment.
Refer to Clarification no. 85
87
Except main equipment BIS (Bureau of Indian
Standard) may be allowed. Please confirm.
NO. Only Internationally recognized standards can be used.
88
Please reduce the guarantee period form 5 year
to 2 year.
Refer to this TAC Item 1.22 below for updated guarantee period
89
Employer’s Requirements
Clause 2.11
Please specify thickness of zinc coating for
galvanizing on structure.
All equipment and design shall meet the standards as stated within
the Section 2.11 of the Technical Specification and suitable to meet
the local environment. The thickness of coating shall however be not
less than 610gm of zinc per square meter.
90
We shall submit only type test reports.
Conducting of any type test is not considered.
Also confirm that all type test, routine test and
site test shall be as per respective IEC.
Refer to Clarification No.47
91
Please provide details (Make and type) of shunt
reactor protection scheme for checking
compatibility.
The shunt reactor control and protection at Mariakani are new panels and shall be designed by the Contractor.
92 Please provide lead for surplus material. Refer to refer to clause 19.5.2 and 21.17.7.9
93
For 400kV pole discrepancy shall be
<3.3ms for closing and <3.3 ms for opening.
Refer to Technical Specification volume 2 of 2 clause 4.2.1
24 Mariakani 400/220kV Substation
S.No. Clause/Paragraph/Item No. Clarification/Query Response
For 220kV pole discrepancy shall be
<5ms for closing and <3.3 ms for opening.
Please confirm.
25 Mariakani 400/220kV Substation
The following Addendums to Procurement of Mariakani 400/220kV substation
document Volume 2 of 2 are as follows:
Item 1.22 Maintenance, shall be replaced with: “The contractor shall guarantee the
efficient and good working of the Plant under the Contract for a period of 2 years from
the date on which the Project Manager takes over the Plant in accordance with General
Conditions of Contract.”
Additional section to 1.15 Planning and Progress Reports as follows:
1.15.1 Joint Review Meeting
Following the issuing of the Contractor’s preliminary design there shall be a Joint Review meeting. This meeting will include the Contractor’s respective designers, KETRACO and the Consultant engineers.
The Joint review meeting shall be held within the Contractor’s office.
The Contractor shall arrange all transport and accommodation during the time of the joint review meeting for KETRACO’s staff and the Consultant’s engineers.
It is expected that 5 KETRACO engineers shall attend this meeting and 5 Consultant engineers.
The Contractor shall allow a period of 5 days for the joint review meeting and schedule this within the programme.
Item 1.2.1 Mariakani 400/220kV Substation fourth and fifth paragraph shall be
replaced with: The 400kV design is to comprise of six ‘breaker-and-a-half’ diameters.
Two fully equipped diameters will be fed from the Isinya 400kV double circuit
transmission line which is to be diverted into the substation and also connect to two
interbus transformers (IBT 4 and 3). A further two partially equipped diameters will
provide single circuit connections into the 220kV switchyard via 200MVA (IBT 2 and 1).
An 11kV cable connection will be provided from each IBT tertiary winding to each
auxiliary/ earthing transformer.
The proposed substation layout makes provision for future circuits. Two of which have
been identified by KETRACO as double future thermal power plant connections. The
substation design is also to incorporate space for the future double circuit feeders from
Markn Power Plant. The future bays shall be constructed as ‘Skeleton bays’, i.e. full
gantry structures but no electrical equipment (or associated electrical plant foundations)
except the following is required;
The overhead conductors, i.e. earth wire, bus 1 and 2 and the respective high
level transfer conductors
Earth wire
Earth grid
Drainage
26 Mariakani 400/220kV Substation
Cable trenches
Levelled site complete with stone chip
Section VI, K 400/220kV Power Transformers (AIS-AIS) Clause 1.74, shall be
replaced with: “Maximum sound pressure level (NEMA TR1 – 5dB(A)) 83dB(A).”
Section III, Bid Data Sheet, the following shall be inserted: “ITB 12.1” “The choice of
currencies shall be as follows: Any freely convertible currency or combination of up to
three freely convertible currencies”
Additional statement covering item 21.17.12 shall read, “All drainage (excluding
waste water) from the substation shall meet section 21.17.12 of the Employer’s
Requirements in addition soak pits are to be constructed by the Contractor suitable to
meet all drainage needs from the substation.”
Additional statement covering item 21.11 shall read, “Local voltage connection at
11kV shall require cable connection (the cable route shall follow the road, allow 2km
cable route length) to be arranged and constructed by the Contractor. Local water
connection point is 2km distance, to be arranged and constructed by the Contractor.”
Additional statement covering item 21.17.15 PERMANENT ACCESS ROADS
Main Access Road from substation to Mombasa Road
Provide for the design and construction of a 2 Km access road. The road shall be of
permanent construction of concrete type, connecting the main road to the substation.
The road will be a 12m wide road with two lanes of 3.5m with shoulders of 1.5m and
provision for the drainage facilities.
The design is to be done in accordance with the Standard specifications for road and
bridge construction or any other acceptable equivalent design standard to the approval
of the Client. The road will also be designed suitable to transport all the anticipated
equipment to site and sufficient to accommodate a sufficient bending radii of 26m truck
and trailer rigs.
Access Roads within the Substation
The roads shall be of permanent construction of concrete type. The road shall be a 5m
wide road and provision for the drainage facilities as described in the Technical
Specifications. These roads include the access to the permanent housing.
The design is to be done in accordance with the Standard specifications for road and
bridge construction or any other acceptable equivalent design standard to the approval
of the Client.
27 Mariakani 400/220kV Substation
Section VI, K 400/220kV Power Transformers items 1.1 to 1.24 replaced with
400/220kV POWER TRANSFORMERS (AIS-AIS)
UNIT DATA
Required Offered
1. POWER TRANSFORMER
1.1 Manufacturer & Place of manufacturing
1.2 Type designation
1.3 Type
Three-phase Autotransformer, oil-immersed, core type
with tertiary winding
Yes
1.4 Standards
IEC 60076, 60137,
60214
1.5 Altitude
m 216
1.6 Ambient temperature
- Maximum
- Annual average
oC
oC
40
30
1.7 Mounting
Outdoor
1.8 Rated voltage ratio
kV 400
220
11
1.9 Rated frequency
Hz 50
1.10 Vector group (3 phase group connection)
YNa0d11
1.11 Cooling – 2-stage
ONAN/ONAF1/ONAF
2 or
ONAN/ONAF/OFAF
1.12 Function of tertiary winding (TV)
Aux. supply
1.13 Method of earthing
- HV winding Solid
- LV winding Solid
- TV winding _
1.14 Type of windings (graded/non-graded)
- HV winding (Series) Graded
- LV winding (Common) Graded
- TV winding Non-graded
1.15 Rated voltage of windings (Ur)
- HV winding kV 400
- LV winding
- TV winding
Note*: approximate; to manufacturer’s preference
kV
kV
220
11
1.16 Highest voltage for equipment (Um)
28 Mariakani 400/220kV Substation
400/220kV POWER TRANSFORMERS (AIS-AIS)
UNIT DATA
Required Offered
- HV winding kV 420
- LV winding kV 245
- TV winding kV 12
1.17 Rated lightning impulse withstand voltage at:
- HV terminal kV 1425
- LV terminal kV 1050
- Neutral terminal kV 170
- TV winding 75
1.18 Rated switching impulse voltage
- HV terminals
- LV terminals
kV
kV
1050
850
1.19 Rated power frequency withstand voltage at
- HV terminal (design value)
- HV test value (ACLD U1)
- HV test value (ACLD U2 PD measurement))
kV
kV
kV
630
436
388
- LV terminal (design value) kV 460
- Neutral terminal kV 70
- TV terminal kV 28
1.20 Rated power at site conditions (ONAF2 or OFAF), HV &
LV
MVA
200
1.21 Rated power at site conditions (ONAN)
MVA 120
1.22 Rated power of tertiary at site conditions (Full cooling)
MVA 70
1.23 Maximum temperature rise at rated power at:
- Windings
Marikani
K
55
- Hot spot of windings
Marikani
K
68
- Top oil
Marikani
K
50
- Oil at inlet of cooler K
- Oil at outlet of cooler K
- Core K
1.24 Temperature of winding due to short circuit duration of 2
s at rated load
- HV side short circuit rating of 31.5kA oC 250
- LV side short circuit rating of 31.5kA oC 250
The following items are to be added to the Volume 1, Pricing Schedules, Schedule
No 4, Civil Works
29 Mariakani 400/220kV Substation
Item
No
Description Estimated
Quantity
Unit
30.34 Site survey 1 Lot
30.35 Site clearance and earth works 1 Lot
30.36 Temporary works 1 Lot
30.37 Grading and landscaping on completion 1 Lot
30.38 Surface chippings 1 Lot
30.39 Main Access Road from substation to
Mombasa Road
1 Lot
30.40 Access Roads within the Substation 1 Lot
30.41 Drainage system 1 Lot
30.42 Substation perimeter fence including
security
1 Lot
30.43 Substation gates 1 Lot
30.45 Cable trenching / ducts 1 Lot
30.46 Substation road lighting 1 Lot
30.47 Substation compound lighting 1 Lot
30.48 Substation gatehouse 1 Lot
30.49 Substation control / relay building 1 Lot
The following section shall be added to the Procurement documents volume 2 of
after section 11.5
30 Mariakani 400/220kV Substation
11.6 LV CABLES
11.6.1 General
The LV Cable system installed in the substation shall be designed to support auxiliary power,
monitoring and control functions of the substation. The selection of materials, design and installation
shall ensure a high level of availability, minimise damage or disruption to other systems in the event of
a fault and minimise the risk to personnel. Wherever any part of an LV cable circuit is installed within
a room or enclosure containing electrical control or protection equipment or where personnel are
normally present cables employing insulation and sheathing which minimises the production of smoke
and toxic fumes shall be used. Cable installed wholly outdoors may be of a PVC insulated type.
11.6.2 Scope of Works
The supply and services to be performed by the Contractor shall comprise the design, manufacture,
shop testing, packing, transport, insurance, unloading, storage on Site, construction works and
erection, corrosion protection, site testing, submission of documentation, commissioning, and
warranty of the works.
The Contractor is bound to provide complete works, even if the equipment or services to be provided
are not specifically mentioned in the specification.
11.6.3 LV Power and Multicore Cables
The scope of supply shall include the following:
Power cables used for the connection between auxiliary supply system and consumers
such as motors, chargers, sub-distribution boards, local control cubicles,
protection panels, substation control systems, marshalling cubicles, equipment
cabinets and all other users directly fed from the switchgear shall be sized
according to the continuous site rating calculation. These calculations shall be
submitted for approval.
Power cables used for the connection between 500kVA or 315kVA, 11/0.415kV
auxiliary/earthing transformers and L.V.A.C. switchboard; between batteries,
chargers and DC Boards.
Multicore control cables for 110 V D.C. system,
Multicore (control, protection, measuring, alarm and indication) cables used for the
connection of various individual control boards or equipment cabinets to the
remote control panels, protection panels, substation control system, marshalling
cubicles, equipment and consumers, connection between the elements of control
cubicles, connection between telemetry marshalling cubicles and control cubicles
and all other connections.
Cable racks trays and fixing devices for all LV cables.
Cable terminating material for all LV cables.
Corrosion protection.
31 Mariakani 400/220kV Substation
Special equipment, tools and spare parts shall be included as required for proper
maintenance.
11.6.4 Technical Data
Rated voltage 0.6/1 kV
Conductor material Copper
Core insulation Thermosetting or PVC
Protective sheath Galvanized steel-wire armoured and LSOH or PVC
over-sheath.
All parts of the cable installation shall comply with this Specification and the latest revisions of the
relevant IEC standards except where otherwise stated.
11.6.5 General Design Requirements
The low voltage power and multicore cables shall comply with these specifications and the
requirements of the latest revision of the following IEC Standards, except where otherwise stated:
IEC 60189-1/1986, IEC 60189-2/1981 and 60189-3/1988 "Low Frequency Cables and
Wires with PVC Insulation and Sheath".
IEC 60227 "PVC Insulated Cables on Rated Voltages up to and including 450/750 V.
IEC 60228 "Conductors of Insulated Cables".
IEC 60287 "Calculation of the continuous current rating of cables (100% load factor)".
IEC 60724 "Guide to the Short-Circuit Temperature Limits of Electric Cables with a Rated
Voltage Not Exceeding 0,6/1 kV".
IEC 60811 "Common Test Methods for Insulating and Sheathing Materials of Electric
Cables and Optical Cables ".
IEC 60885 "Electric Test Methods for Electric Cables ".
BS 6724 Specification for 600/1000 V and 1900/3300 V armoured electric cables having
thermosetting insulation and low emission of smoke and corrosive gases when affected
by fire
BS EN 50265 “Common Test Methods for Cables under Fire Conditions”
All cables shall be suitable for continuous operation under climatic conditions prevailing on site.
All transient and abnormal conditions, such as overload and short circuits shall be withstood without
detrimental effects.
The cables shall have copper conductor with either PVC insulation and PVC over sheath or
thermosetting insulation with LSOH characteristics as determined by the application.
32 Mariakani 400/220kV Substation
The cables shall be identified at both terminations with stainless steel metallic ferrules engraved with
the reference number, the number and size of cores, the type of cable and the designation.
At those points of interconnection between the wiring carried out by separate contractors where a
change of number cannot be avoided double ferrules shall be provided on each wire. The change of
numbering shall be shown on the appropriate diagram of the equipment.
The Contractor shall provide a complete set of cable schedules listing all cables required for
connecting the equipment supplied under this Contract.
Cable schedules listing all cables and their points of termination including details of cable, number of
cores, core reference, core size, number of cores in use and cable length etc. shall be provided.
The Contractor shall ensure that the core identification at their terminals corresponds to the above-
mentioned schedule.
The cables shall be laid on trays in single layers in such a manner that they can be replaced or added
to without difficulty.
In general, the cables for double in-feeds from the switchgear, transformers, distribution boards and
cubicles shall be laid separately so that in the event of a short-circuit in one in-feed, the other is not
affected.
All AC and DC control and power circuits shall be segregated from one another and the circuits to
main protective gear shall be segregated from those for back up protection.
The cable sheaths must be resistant to solar radiation, the effect of oil, bacterial action, insects and
rodents. They must be suitable for laying indoors, outdoors, underground and in water.
All cables installed in concrete troughs within the substation shall have anti-termite protection applied
to the outer covering in the form of a chemical additive. The chemical used, percentage strength and
the changes in electrical and mechanical properties of the outer covering shall be stated in the
Technical Schedules.
The screen of the shielded cables shall be brought out and earthed at one end. The armouring of the
cables shall be earthed at both ends.
When laying the cables on trays, vertical runs, in cable ducts, etc. and when choosing the sizes of
cables, care must be taken to ensure that adequate ventilation is guaranteed and that there is no risk
of thermal overloading, undue pressure or distortions of the cables.
11.7 Low Voltage Power Cables
The conductors for power supply cables at voltages up to 600/1000 V AC shall be plain annealed
copper wire complying with IEC 60228 as applicable, with circular or shaped conductors. All cores
shall be identified by phase colours.
The conductor sizes shall be in accordance with loading of the individual circuits under the site
conditions and to the approval of KETRACO.
33 Mariakani 400/220kV Substation
During motor starting or re-acceleration in groups, the voltage at the motor terminals shall not fall
below 80% of the rated voltage. Cables and systems shall be sized to meet these criteria.
The basis of voltage drop calculations shall be for worst case, i.e. minimum fault level and outage of
supply feeders or transformers.
The maximum permissible volt drop in cables shall be:
Feeders and sub-feeders 1%,
Motors branch circuits 2.5% (from power centre to load terminals),
Lighting sub-circuits 2.5% (from lighting switchboard to furthest fitting).
A derating factor based on the manufacturer’s recommendations shall be applied to cable
vendors stated current capacities, taking into account grouping factor, ambient
temperature and environmental conditions.
Cable shall be sized by consideration of:
Nameplate full load current of equipment,
Current carrying capacity after de-rating,
Voltage drop,
Short circuit rating.
The minimum cross-section of standard conductors shall be 2.5 mm².
The low voltage power cables shall consist of single, two, three and four core-cables.
On the low-voltage side, the cable connection between the station service transformers and the 0.4
kV infeed cubicles shall consist of single conductor power cables.
The connections between batteries or rectifiers respectively and the DC distribution board shall
generally consist of single core power cables.
11.7.1 Low Voltage Multicore Cables
The conductors for power supply cables at voltages up to 600/1000 V AC and for all 110 V DC
protection, control, alarm and indication shall be plain annealed copper wire complying with IEC
60228 as applicable or equivalent and all cores shall be clearly identified by printed numbers at
regular intervals.
The minimum conductor size shall be not less than seven strands of 0.67 mm diameter wire and the
minimum cross-sectional area shall be not less than 2.5mm². In special cases for light current
installations single strand, annealed copper conductors with a cross section of 1.5mm² may be used.
Also, conductor sizes less than 2.5mm² may be used for specific electronic circuits (e.g. ribbon cable)
subject to KETRACO’s approval.
34 Mariakani 400/220kV Substation
All multicore cables shall have stranded copper conductors.
Multicore cables of 7 cores and above shall have a minimum of ten percent (10%) spare cores over
the original design requirements.
The number of cores in multicore cables shall be selected from the following numbers: 2, 3, 4, 7, 12,
19, 27 and 37.
The multicore cable tails shall be so bound that each wire may be traced to its cable without difficulty.
The screens of screened pairs of multipair cables shall be earthed at one end of the cable only. The
position of the earthing connections shall be shown clearly on the diagram.
All spare cores shall be earthed at both ends of the multicore cable.
The Contractor shall submit full details of all cable loads and in the case of interposing current
transformer connections, the loop resistance of each circuit.
An instrument transformer cable may transmit the current or voltage from only one transformer. If the
same voltage is required for different purposes (e.g. protection, measurement, metering) each voltage
transformer circuit must be wired via a separate MCB to the switchgear control cabinets.
11.7.2 Termination of Cables and Wires
All cables shall be terminated in accordance with the manufacturer’s recommendations and the cable
cores shall be long enough to be terminated to any terminal in an enclosure without extension. All
cables shall enter cubicles and boxes from bottom side.
PVC sheathed cables shall be terminated by compression glands complying with BS 6121 (or
equivalent).
Where cable cores are liable to be in contact with oil or oil vapour the insulation shall be unaffected by
oil.
The Contractor must terminate all power and control cables inside the appropriate cubicle. The spare
cores of all multicore cables shall be numbered and terminated at a terminal block in the cubicle.
AC terminals shall be clearly colour coded and shrouded.
Colours shall be marked on cable box, cable tail ends and single core cables at all connecting points
and/or any positions KETRACO may determine. Cable boxes shall be marked with stamped stainless
steel labels indicating the purpose of the supply where such supply is not obvious.
11.7.3 Installation Requirements
The following requirements shall apply:
HV Power Cables shall be routed in separate cable troughs.
35 Mariakani 400/220kV Substation
LV power cables, multicore cables and telecommunication cables shall each be routed in
separate trays, racks, ducts, troughs or compartments separated by steel sheet
barriers.
Fibre optic cable shall be routed and installed such that they are protected from
deformation or damage by auxiliary power or control cables throughout their
installed length.
Sufficient space shall be allowed to run in each duct or compartment the necessary draw
wires, being of non-corrosive metal and having devices for securing the
conductors,
A spare capacity of 20% shall be provided on cable trays, ladder racks, ducts,
compartments, or openings in walls and floors,
Openings in floors and foundation pads shall be large enough to permit free movement of
cables during installation,
Channels and ducts shall be sealed where they enter a building to prevent the ingress of
moisture, gases and vermin,
Openings in walls and floors shall be sealed after the cable installation with a fireproof
barrier,
Cabling and wiring installations shall be arranged to minimize the risk of fire and damage
which might be caused in the event of fire,
Only one layer of cables shall be laid on one tray or in one cable channel,
All cables leaving buildings for outside plant shall be laid in cable ducts,
Where cables emerge from grade they shall be protected by a section of steel pipe
extending 150 mm above grade,
Cables above ground shall be run on galvanized cable racks, trays or supports, suitably
clipped to prevent movement. Care shall be taken to provide for differential
movement between the structures.
Protection from direct sunlight shall be provided by means of suitable sunshades
continuously covering the cable and of the same materials as the rack/tray.
Cable straps shall be made of stainless steel.
11.8 Inspection And Tests
11.8.1 General
Tests shall be carried out in order to determine whether the material and equipment comply with the
required properties.
All tests on material and equipment shall be carried out in accordance with IEC Standards. If some
tests are not covered or if a method of testing is not specified in IEC Standards or if there are options
36 Mariakani 400/220kV Substation
in relevant IEC Standards the Contractor shall submit the method by which he proposes to conduct
the tests to KETRACO for approval.
The following lists of tests do not restrict KETRACO’s right to call for further tests if considered
necessary.
11.8.2 Workshop Tests
11.8.2.1 Type Tests
Type tests shall be performed on each type and rating of the specified equipment with purpose of
proving its properties.
The following type tests shall be performed:
Partial discharge test at room temperature.
Bending test followed by partial discharge test.
Measurement of power factor depending on temperature.
Measurement of insulation resistance at room temperature and service temperature.
Impulse voltage withstand test.
Dielectric test by DC voltage preferably.
11.8.2.2 Routine Tests
Routine test shall be performed at each item of equipment to be supplied for the purpose of revealing
faults in material or construction. They shall not impair the properties and reliability of a test object or
reduce its lifetime.
The following routine tests shall be performed on all lengths of cables and all accessories to be
supplied:
General inspection.
Examination of sheath, armour and protective coverings, as well as examination of
insulation, to be performed after bending test.
Measurement of conductor resistance.
High voltage test.
High voltage test on outer sheath.
37 Mariakani 400/220kV Substation
11.8.3 Site Tests
On arrival at site, during installation and after complete installation, all items of equipment shall be
inspected and tested in order to check quality, correct operation and correct installation of the
equipment.
The following tests shall be performed:
1. General inspection of the cable routes, verification of proper installation, fixing to
the racks, bending radius, etc.
2. Verification of proper earthing of the screen and armouring.
3. Measurement of cables insulation resistance.
4. Verification of proper condition of external surfaces.
11.8.4 Spare Parts
Works to be done under this section include the delivery of spare parts. Requirements for spare parts
are described in General Technical Requirements and quantities in Schedule of Prices.
Any additional spare parts recommended by the Tenderer shall be listed and priced.
11.8.5 Training
Works to be done under this section include training of KETRACO’s personnel to operate and
maintain equipment efficiently and safely.
11.8.6 Documentation
The Contractor shall provide all necessary drawings, design specifications, design details, operation
and maintenance manuals and other information in accordance with General Technical
Requirements.
11.8.7 Documentation With Tender
The Tender shall contain at least the following information and documents:
1. Outline drawings showing the overall dimensions of the proposed cables;
2. Manufacturing specification of the proposed cables;
3. Catalogues, literature and reference lists of proposed cables;
4. Type test certificates from an independent testing authority or independently
witnessed;
5. Quality Management System Manual and ISO Certificate of the equipment
manufacturer.
38 Mariakani 400/220kV Substation
BID DRAWINGS ISSUED UNDER TAC2
The following drawings are provided with this addendum document:
PB-KET-2012-D-223 Mariakani 220kV Single Line Diagram
PB-KET-2012-D-224 Mariakani 400kV Single Line Diagram
PB-KET-2012-L-234 Mariakani 220kV Layout
PB-KET-2012-L-235 Mariakani 220kV Elevations
PB-KET-2012-P-287 Mariakani 400/220kV Substation SCS Single Line Diagram
PB-KET-2012-P-288 Mariakani 400/220kV Substation LVAC Single Line Diagram
PB-KET-2012-P-289 Mariakani 400/220kV Substation 110V DC Single Line Diagram
PB-KET-2012-L-201 400kV Double Tension H/Ware fittings for Quad ACSR Lark Conductor
PB-KET-2012-L-203 Tension clamp with Al encasing suitable for ACS Earthwire (7/3.26)
PB-KET-2012-L-205 Jumper Spacer for ACSR Lark Conductor (400kV)
PB-KET-2012-L-206 Single Suspension (Pilot) H/Ware fittings for Single ACSR Canary Conductor (220kV)
PB-KET-2012-L-207 Quad Spacer Damper for ACSR Lark Conductor (400kV)
PB-KET-2012-L-208 400kV Pilot Suspension H/Ware fittings suitable for ACSR Quad Lark Conductor
PB-KET-2012-L-209 Single Tension H/Ware fittings for Single ACSR Canary Conductor (220kV)
PB-KET-2012-L-217 Double dead end set passing for OPGW cable diameter 19.6 – 20.6mm - 28110225 (F-0887)
PB-KET-2012-L-218 Single dead end set for OPGW cable diameter 19.6 – 20.6mm – 28110224 (F-0886)
PB-KET-2012-L-219 Tower Hinge for double tension hardware fittings suitable for quad ACSR lark conductor (400kV)
Miscellaneous
39 Mariakani 400/220kV Substation
Drawings
6861162 Confirmed Outline Drawing (Shunt Reactor)
182AKPDE2006A Clearance diagram for Existing 220kV Tower- to be dismantled
182AKPDE2006A Clearance diagram for Existing 220kV Terminal Tower
182AKPDE40010 Clearance diagram for Existing 400kV Terminal Tower
SDH-1/2- Single Unit Staff Housing for senior staff (Annex 21.5 .1)
DDH-2/2- Double Unit Staff Housing for sub-ordinate staff (Annex 21.5.2)
Existing Telecommunications and OPGW System
1KHD636398 Sheet 504 Telecommunication System - System Layouts Legend
1KHD636398 Sheet 500 Telecommunication System – Western Region
1KHD636398 Sheet 501 Telecommunication System – Mount Kenya Region
1KHD636398 Sheet 502 Telecommunication System – Coastal Region
1KHD636398 Sheet 503 Telecommunication System – Nairobi Region
1KSE 000 535D410 Sheet 1 to 9 Block Diagram Network Manager
PB-KET-2012-D-233 Mariakani Overall Layout
PB-KET-2012-D-236 Mariakani 400kV Layout
PB-KET-2012-L-237
PROTECTION DRAWINGS
Mariakani 400kV Elevations
PB-KET-2012-P-280 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 1
PB-KET-2012-P-281 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 2
PB-KET-2012-P-282 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 3
40 Mariakani 400/220kV Substation
PB-KET-2012-P-283 Protection Single Line Diagram – Mariakani 400/220kV Substation 400kV Diameter 4
PB-KET-2012-P-284 Protection Single Line Diagram – Mariakani 400/220kV Substation 220kV Diameter 1
PB-KET-2012-P-285 Protection Single Line Diagram – Mariakani 400/220kV Substation 220kV Diameter 2
PB-KET-2012-P-286 Protection Single Line Diagram – Mariakani 400/220kV Substation 220kV Diameter 3
64161A-PBP-L-0016 Mariakani Substation Layout