IEC TR 61366-5:1998

Hydraulic turbines, storage pumps and pump-turbines - Tendering Documents - Part 5: Guidelines for technical specifications for tubular turbines

IEC TR 61366-5:1998, which is a technical report, is intended to assist in the preparation of Tendering documents and tendering proposals and in the evaluation of tenders for hydraulic machines. This part of IEC 61366 provides guidelines for tubular turbines.

General Information

• Status: Published
• Publication Date: 10-Mar-1998
• ICS: 27.140 - Hydraulic energy engineering
• Technical Committee: TC 4 - Hydraulic turbines
• Drafting Committee: WG 19 - TC 4/WG 19
• Current Stage: PPUB - Publication issued
• Start Date: 11-Mar-1998
• Completion Date: 31-Jan-1998

Overview

IEC TR 61366-5:1998 is a Type 3 Technical Report from the International Electrotechnical Commission (IEC) that provides guidelines for technical specifications for tubular turbines. Published as the first edition in 1998, this report is part of the IEC 61366 series on tendering documents for hydraulic turbines, storage pumps and pump‑turbines. Its primary purpose is to assist in the preparation of tendering documents, tender proposals and in the evaluation of tenders for tubular turbine procurement and contracting.

Key topics

The report outlines the structure and content that should appear in technical specifications for tubular turbines. Major topics covered include:

• Scope and reference documents relevant to tendering and specifications.
• Technical requirements such as scope of work, contract limits, employer-supplied items, design conditions, and guaranteed performance.
• Mechanical design criteria and required design documentation.
• Materials, construction, shop inspection and testing expectations.
• Fixed/embedded components (e.g., bulb structure, discharge ring, draft tube).
• Stationary/removable components (inner/outer rings, guide vanes).
• Guide vane regulating apparatus (servomotors, linkages, overload protection).
• Rotating parts, bearings, seals and gearbox specifications (runner, main shaft, bearings).
• Thrust and counter‑thrust bearing requirements and supporting data.
• Auxiliary systems and instrumentation (lubrication, drainage, control and protection).
• Spare parts, model acceptance tests, site installation and commissioning tests, and field acceptance tests (including cavitation/pitting inspection).

Practical applications

IEC TR 61366-5 is a practical tool for producing clear, contract‑ready technical specifications for tubular turbine equipment in hydropower projects. Use cases include:

• Preparing consistent tendering documents for procurement of tubular turbines.
• Guiding tenderers and contractors in preparing compliant proposals.
• Providing evaluation criteria for employers and procurement/engineering teams.
• Defining testing, installation, commissioning and field acceptance procedures.
• Aligning manufacturer deliverables (design documents, shop tests, spare parts) with project requirements.

Who should use this standard

• Project owners and Employers drafting tendering documentation
• Engineering consultants and specification writers
• Turbine manufacturers and suppliers preparing bids
• Procurement and contract evaluation teams
• Commissioning and testing specialists

Related standards

IEC TR 61366-5 complements other parts of the IEC 61366 series (Parts 1–7), each addressing specific machine types (Francis, Pelton, Kaplan, pump‑turbines, storage pumps). Refer to Part 1 for general provisions and annexes that support Parts 2–7.

Keywords: IEC TR 61366-5:1998, tubular turbines, technical specifications, tendering documents, hydraulic turbines, hydropower procurement, turbine commissioning.

Standards Content (Sample)

TECHNICAL
IEC
REPORT
61366-5
First edition
1998-03
Hydraulic turbines, storage pumps
and pump-turbines –
Tendering Documents
Part 5:
Guidelines for technical specifications
for tubular turbines
Turbines hydrauliques, pompes d'accumulation
et pompes-turbines –
Document d'appel d'offres –
Partie 5:
Guide des spécifications techniques pour
les turbines tubulaires
Reference number
CEI/IEC 61366-5:1998(E)
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series.
Consolidated publications
Consolidated versions of some IEC publications including amendments are
available. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the
base publication, the base publication incorporating amendment 1 and the base
publication incorporating amendments 1 and 2.
Validity of this publication
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology.
Information relating to the date of the reconfirmation of the publication is available
in the IEC catalogue.
Information on the revision work, the issue of revised editions and amendments may
be obtained from IEC National Committees and from the following IEC sources:
• IEC Bulletin
• IEC Yearbook
On-line access*
• Catalogue of IEC publications
Published yearly with regular updates
(On-line access)*
Terminology, graphical and letter symbols
For general terminology, readers are referred to IEC 60050: International
Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets Graphical symbols
and IEC 60617:
for diagrams.
IEC publications prepared by the same technical committee
The attention of readers is drawn to the end pages of this publication which list the
IEC publications issued by the technical committee which has prepared the present
publication.
* See web site address on title page.

TECHNICAL
IEC
REPORT – TYPE 3
61366-5
First edition
1998-03
Hydraulic turbines, storage pumps
and pump-turbines –
Tendering Documents
Part 5:
Guidelines for technical specifications
for tubular turbines
Turbines hydrauliques, pompes d'accumulation
et pompes-turbines –
Document d'appel d'offres –
Partie 5:
Guide des spécifications techniques pour
les turbines tubulaires
 IEC 1998  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http: //www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
V
International Electrotechnical Commission
For price, see current catalogue

– 2 – 61366-5 © IEC:1998(E)
CONTENTS
Page
FOREWORD . 4
Clause
0 Introduction to technical specifications .
1 Scope. 9
2 Reference documents . 9
3 Technical requirements. 9
3.1 Scope of work. 9
3.2 Limits of the contract . 10
3.3 Supply by Employer . 10
3.4 Design conditions . 11
3.5 Technical performance and other guarantees. 13
3.6 Mechanical design criteria . 16
3.7 Design documentation . 17
3.8 Materials and construction . 18
3.9 Shop inspection and testing . 19
4 Technical specifications for fixed/embedded components. 20
4.1 Bulb structure and hatch cover. 20
4.2 Stay ring (if employed in design) . 21
4.3 Discharge ring . 21
4.4 Draft tube and draft tube liner . 22
4.5 Upstream and downstream pressure taps and pipes. 22
5 Technical specifications for stationary/removable components . 22
5.1 Inner and outer rings . 22
5.2 Guide vanes . 22
6 Technical specifications for guide vane regulating apparatus. 23
6.1 Servomotors . 23
6.2 Connecting rods . 23
6.3 Regulating ring . 23
6.4 Guide vane linkage . 23
6.5 Guide vane overload protection. 23
6.6 Locking devices. 24
6.7 Counter weight . 24
7 Technical specifications for rotating parts, bearings, seals and gear box (if used). 24
7.1 Runner . 24
7.2 Runner blade regulating apparatus . 24
7.3 Main shaft . 25

61366-5 © IEC:1998(E) – 3 –
7.4 Turbine guide bearing. 26
7.5 Main shaft seal . 26
7.6 Standstill (maintenance) seal . 26
7.7 Gearbox (if used). 26
8 Technical specifications for thrust and counter-thurst bearing. 27
8.1 Design data . 27
8.2 Bearing support . 27
8.3 Bearing assembly . 27
9 Technical specifications for miscellaneous components . 27
9.1 Walkways, access platforms and stairs . 27
9.2 Lifting fixtures. 28
9.3 Special tools. 28
9.4 Standard tools . 28
9.5 Nameplate. 28
10 Technical specifications for auxiliary systems. 28
10.1 Bearing lubrication system . 28
10.2 Turbine drainage . 28
10.3 Lubrication – guide vane regulating system . 28
11 Technical specifications for instrumentation . 29
11.1 Controls. 29
11.2 Indication. 29
11.3 Protection. 29
12 Spare parts. 29
13 Model acceptance tests . 29
14 Site installation and commissioning tests . 30
14.1 General . 30
14.2 Installation procedures. 30
14.3 Tests during installation . 31
14.4 Commissioning tests. 31
15 Field acceptance tests . 31
15.1 Scope and reports . 31
15.2 Inspection of cavitating pitting. 31

– 4 – 61366-5 © IEC:1998(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
HYDRAULIC TURBINES, STORAGE PUMPS AND PUMP-TURBINES –
TENDERING DOCUMENTS –
Part 5: Guidelines for technical specifications
for tubular turbines
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
report of one of the following types:
• type 1, when the required support cannot be obtained for the publication of an International
Standard, despite repeated efforts;
• type 2, when the subject is still under technical development or where for any other reason
there is the future but no immediate possibility of an agreement on an International
Standard;
• type 3, when a technical committee has collected data of a different kind from that which is
normally published as an International Standard, for example "state of the art".
Technical reports of types 1 and 2 are subject to review within three years of publication to
decide whether they can be transformed into International Standards. Technical reports of
type 3 do not necessarily have to be reviewed until the data they provide are considered to be
no longer valid or useful.
IEC 61366-5, which is a technical report of type 3, has been prepared by IEC technical
committee 4: Hydraulic turbines.

61366-5 © IEC:1998(E) – 5 –
The text of this technical report is based on the following documents:
Committee draft Report on voting
4/110/CDV 4/122/RVC
Full information on the voting for the approval of this technical report can be found in the report
on voting indicated in the above table.
Technical Report IEC 61366-5 is one of a series which deals with Tendering documents for
hydraulic turbines, storage pumps and pump-turbines. The series consists of seven parts:
Part 1: General and annexes (IEC 61366-1)
Part 2: Guidelines for technical specification for Francis turbines (IEC 61366-2)
Part 3: Guidelines for technical specification for Pelton turbines (IEC 61366-3)
Part 4: Guidelines for technical specification for Kaplan and propeller turbines (IEC 61366-4)
Part 5: Guidelines for technical specification for tubular turbines (IEC 61366-5)
Part 6: Guidelines for technical specification for pump-turbines (IEC 61366-6)
Part 7: Guidelines for technical specification for storage pumps (IEC 61366-7)
Parts 2 to 7 are "stand-alone" publications which when used with Part 1 contain guidelines for a
specific machine type (i.e. Parts 1 and 4 represent the combined guide for Kaplan and
propeller turbines). A summary of the proposed contents for a typical set of Tendering
documents is given in the following table 1 and annex A. Table 1 summarizes the arrangement
of each part of this guide and serves as a reference for the various chapters and sections of
the Tendering documents (see 3.2 of this part).

Table 1 – Summary of guide for the preparation of Tendering documents for hydraulic turbines, storage pumps and pump-turbines
CONTENTS OF GUIDE IEC 61366-1 TO IEC 61366-7 SAMPLE TABLE OF CONTENTS OF TENDERING DOCUMENTS (TD)
(Example for the Francis turbines; see 61366-1, annex A)
Part Clause Title Chapter Title
1 General and annexes 1 Tendering requirements
1– 2 Project information
1 1 Object and scope of this guide 3 General conditions
1 2 Reference documents and definitions 4 Special conditions
1 3 Arrangement of Tendering documents 5 General requirements
1 4 Guidelines for tendering requirements 6 Technical specifications
1 5 Guidelines for project information 6.1 Technical requirements
1 6 Guidelines for general conditions, special conditions and general 6.1.1 Scope of work
requirements 6.1.2 Limits of the contract
6.1.3 Supply by Employer
1 Annexes 6.1.4 Design conditions
6.1.5 Performance and other guarantees
A Sample table of contents of Tendering documents for Francis turbines 6.1.6 Mechanical design criteria
B Comments on factors for evaluation of tenders 6.1.7 Design documentation
C Check list for tender form 6.1.8 Materials and construction
D Examples of technical data sheets 6.1.9 Shop inspection and testing
E Technical performance guarantees 6.2 Technical specifications for fixed/embedded components
F Example of cavitation pitting guarantees 6.3 Technical specifications for stationary/removable components
G Check list for model test specifications 6.4 Technical specifications for guide vane regulating apparatus
H Sand erosion considerations 6.5 Technical specifications for rotating parts, bearings and seals
6.6 Technical specifications for thrust bearings
2 to 7 Technical specifications 6.7 Technical specifications for miscellaneous components
6.8 Technical specifications for auxiliary systems
2 Francis turbines 6.9 Technical specifications for instrumentation
3 Pelton turbines 6.10 Spare parts
4 Kaplan and propeller turbines 6.11 Model tests
5 Tubular turbines 6.12 Installation and commissioning
6 Pump-turbines 6.13 Field acceptance tests
7 Storage pumps
61366-5 © IEC:1998(E) – 7 –
HYDRAULIC TURBINES, STORAGE PUMPS AND PUMP-TURBINES –
TENDERING DOCUMENTS –
Part 2: Guidelines for technical specifications
for tubular turbines
0 Introduction to technical specifications
The main purpose of the technical specifications is to describe the specific technical
requirements for the hydraulic machine for which the Tendering documents (TD) are being
issued. To achieve clarity and to avoid confusion in contract administration, the Employer
should not specify anything in the technical specifications which is of importance only to the
preparation of the tender. Such information and instructions should be given only in the
instructions to Tenderers (ITT). Accordingly, the ITT may refer to other chapters and sections
of the Tendering documents but not vice versa. As a general rule the word "Tenderer" should
be confined in use only to TD Chapter 1 "Tendering requirements"; elsewhere the term
"Contractor" should be used.
Special attention should be given to items of a project specific nature such as materials,
protective coating systems, mechanical piping systems, electrical systems and instrumentation.
It is common for the Employer to use technical standards for such items which would apply to
all contracts for a particular project or projects. In this event, detailed technical standards
should be specified in TD Chapter 5 "General requirements".
Technical specifications for the various types of hydraulic machines included in this guide are
provided in the following parts:
– Francis turbines (Part 2);
– Pelton turbines (Part 3);
– Propeller and Kaplan turbines (Part 4);
– Tubular turbines (Part 5);
– Pump-turbines (Part 6);
– Storage pumps (Part 7).
The guidelines for preparation of tubular turbine specifications include technical specifications
for the following:
– Design conditions: Project arrangement, hydraulic conditions, mode of operation, generator
characteristics, transient behaviour data, stability of the system, noise, vibration, pressure
fluctuations and safety requirements.
– Technical performance and other guarantees:
ypower;
ydischarge;
yefficiency;
ymaximum momentary pressure;
yminimum momentary pressure;
ymaximum momentary overspeed;
ymaximum steady-state runaway speed;

– 8 – 61366-5 © IEC:1998(E)
ycavitation pitting;
yhydraulic thrust;
ymaximum weights and dimensions for transportation, erection and maintenance.
– Mechanical design criteria: design standards, stresses and deflections and special design
considerations.
– Design documentation: Contractor’s input needed for the Employer's design, the
Contractor's drawings and data, Contractor's review of the Employer's design and technical
reports by Contractor.
– Materials and construction: material selection and standards, quality assurance procedures,
shop methods and personnel, corrosion protection and painting.
– Shop inspection and testing: general requirements and reports, material tests and
certificates, dimensional checks, shop assembly and tests.
– Fixed/embedded components: generator hatch cover or pit, stay ring, discharge ring (if
any), draft tube, draft tube liner foundations anchorage, upstream and downstream
pressure taps and pipes.
– Stationary/removable components: bulb nose, generator access shaft inner and outer guide
rings and guide vanes.
– Regulating apparatus: servomotor, counterweight, connecting rods, regulating ring, guide
vane linkage, system, guide vane overload protection and locking devices.
– Rotating parts, bearings and seals: runner, main shaft, guide bearing, main shaft seal, oil
head and runner blade regulation system with servomotor assembly with oil supply, linkage
system, crosshead and oilhead.
– Thrust and counter-thrust bearing: bearing support, thrust collar and counter-thrust bearing
pads and rings, oil sump and instrumentation.
– Gear box: gear box and related components.
– Miscellaneous components: walkways, platforms, lifting fixtures, special tools, standard
tools and nameplate.
– Auxiliary systems: water supply to main shaft seal, turbine drainage, lubrication-guide vane
regulating system, and oil supply to bearings.
– Instrumentation: controls, indication and protection.
– Spare parts: basic spare parts.
– Model acceptance tests: test requirements.
– Site installation and commissioning test: installation procedures and commissioning.
– Field acceptance tests: scope of field test scope and reports and inspection of cavitation
pitting.
An example of the proposed table of contents for Tendering documents for a Francis turbine is
given in annex A of IEC 61366-1. The example does not include technical specifications for the
control system, relief valves, or high and low pressure slide valves or gates which, at the
Employer's option, may be included in the Tendering documents for the turbine or may be
specified in separate documents.
Chapter 6 (technical specifications) of the Tendering documents should be arranged as follows:
6.1 Technical requirements;
6.2 Technical specifications for fixed/embedded components;
6.3 Technical specifications for stationary/removable components;
6.4 Technical specifications for guide vane regulating apparatus;
6.5 Technical specifications for rotating parts, guide bearings and seals;
6.6 Technical specifications for thrust bearing;
6.7 Technical specifications for gear box;

61366-5 © IEC:1998(E) – 9 –
6.8 Technical specifications for miscellaneous components;
6.9 Technical specifications for auxiliary systems;
6.10 Technical specifications for instrumentation;
6.11 Spare parts;
6.12 Model acceptance tests
6.13 Site installation and commissioning
6.14 Field acceptance tests
1 Scope
This technical report, referred to herein as the Guide, is intended to assist in the preparation of
Tendering documents and tendering proposals and in the evaluation of tenders for hydraulic
machines. This part of IEC 61366 provides guidelines for tubular turbines.
2 Reference documents
IEC 60041:1992, Field acceptance tests to determine the hydraulic performance of hydraulic
turbines, storage pumps and pump-turbines
IEC 60193:1965, International code for model acceptance tests of hydraulic turbines
IEC 60308:1970, International code for testing of speed governing systems for hydraulic
turbines
IEC 60545:1976, Guide for commissioning, operation and maintenance of hydraulic turbines
IEC 60609:1978, Cavitation pitting evaluation in hydraulic turbines, storage pumps and pump-
turbines
IEC 60994:1991, Guide for field measurement of vibrations and pulsations in hydraulic
machines (turbines, storage pumps and pump turbines)
1)
IEC 61362, Guide to specification of hydro-turbine control systems
ISO 3740:1980, Acoustics – Determination of sound power levels of noise sources – Guidelines
for the use of basic standards and for the preparation of noise test codes
3 Technical requirements
3.1 Scope of work
This subclause should describe the scope of work and the responsibilities which are to be
conferred upon the Contractor. The general statement of scope of work presented in
2)
TD subsection 2.1 (5.1 ofIEC 61366-1) shall be consistent with what is presented here. In a
similar manner, pay items in the tender form, TD section 1.2 (4.2 of IEC 61366-1) should be
defined directly from TD subsection 6.1.1.
The scope of work should begin with a general statement which outlines the various elements
of the work including (where applicable) the design, model testing, supply of materials and
labour, fabrication, machining, quality assurance, quality control, shop assembly, shop testing,
spare parts, transportation to site, site installation, commissioning, acceptance testing,
warranty and other services specified or required for the items of work.
___________
1)
To be published.
2)
All references to Tendering documents (TD) apply to annex A of IEC 61366-1.

– 10 – 61366-5 © IEC:1998(E)
The general statement should be followed by a specific and detailed list of the major items
which the Employer wishes to have as separate payment items in the tender form, for example:
Item Description
1 Six (6) complete bulb type Kaplan turbines each with a specified power of not less than
10 200 kW at the shaft coupling under a specified hydraulic energy of 98 J/kg (specified
head of 10 m);
2 Turbine model testing;
3 Tools, slings and handling devices required for maintenance of the turbines;
4 Transportation and delivery to site;
5 Site installation, commissioning, and acceptance testing of the turbines;
6 Preparation and submission of operation and maintenance manual and training of
Employer's operating and maintenance staff in optimum use of these manuals; and
7 Spare parts required for operation and maintenance."
3.2 Limits of the contract
This subclause, making reference to the Employer's drawings and data, should describe the
limits of the contract considering the following:
– details and location of the upstream high-pressure reference section;
– responsibility for connection of high-pressure reference section at site;
– details and location of the downstream low-pressure reference section;
– details and location of the upstream termination of the water passage liner;
– details and location of the downstream termination of the draft tube liner;
– orientation and location of the turbine/generator shaft flange interface;
– responsibility for flange coupling bolts, nuts and nut guards at generator/turbine coupling,
including drilling jig;
– responsibility for bolts, nuts, gaskets at piping termination;
– termination of governor piping;
– termination of drainage piping;
– termination of bearings lubricating oil piping;
– termination of shaft seal piping (if any);
– termination points and junction boxes for wiring power, control, indication, protection, and
lighting;
– compressed air for service and other functions.
NOTE – Contract limits will change considerably if other major items of equipment (such as speed governor system,
turbine downstream gate, generators, excitation systems, control metering and relaying systems, switchgear, and
power transformers) are included with the turbine equipment in a common set of Tendering documents.
3.3 Supply by Employer
This subclause should be complementary to 5.6 of IEC 61366-1 (TD 2.6) and should list the
items and services which will be the responsibility of the Employer. The following should be
considered:
– services during site installation and testing;
– temporary enclosures for site storage of turbine parts or for erection;
– installation in primary concrete of small items provided by the Contractor, such as anchors,
sole plates, and piping provided by the Contractor;

61366-5 © IEC:1998(E) – 11 –
– concrete for embedment of turbine components - supply, placement and control including
monitoring and verification during and after concrete placement by others;
– grout injection, if required, either within or around turbine components;
– powerhouse crane and operator;
– connections to powerhouse air, oil and water piping systems;
– supply of filtered water for turbine shaft seal;
– electrical wiring and hardware external to specified termination points;
– electric motor starters and controls;
– control, annunciation and protection systems external to specified termination points;
– external lubricating oil storage, distribution, and purification systems;
– lubricants, bearing and governor oil to the Contractor's specifications.
It should be stated that any materials or services required for installation and commissioning of
the units, and not specifically mentioned in the above list of the Employer supplied items and
services are to be provided by the Contractor under the contract.
3.4 Design conditions
3.4.1 Project arrangement
The detailed project arrangement should contain the Employer's description together with
general arrangement drawings (by the Employer) of the powerhouse and waterways at the low
and high-pressure sides such as channels, galleries, penstocks, gear box, valves/gates, etc.
The description should be an extension of the applicable data provided in TD chapter 2 "Project
information". The data shall be sufficiently clear so that the Contractor is aware of physical
conditions which may influence the detailed design.
In any event, the Employer should retain responsibility for specifying values of all parameters
on which guarantees are based, as part of the overall design of the plant. This applies
particularly to the correct inlet and outlet conditions and in the coordination of the interaction
between the hydraulic machine and waterways.
3.4.2 Hydraulic conditions
This subclause should present the hydraulic conditions under which the Employer proposes to
operate the completed facility such as:
– range of specific hydraulic energy (head) of the plant;
– specific hydraulic energy losses between headwater level and high-pressure reference
section of the machine (E );
L 3-1
– specific hydraulic energy losses between the low-pressure reference section and tailwater
level (E );
L 2-4
– specific hydraulic energy (head) of the machine (see 2.5 of IEC 61366-1);
– headwater levels, maximum, minimum and normal and when no water is flowing;
– tailwater levels, maximum, minimum and normal and when no water is flowing;
– minimum tailwater level as a function of discharge for cavitation guarantee;
– power values in the range of specific hydraulic energy (head);
– maximum specific hydraulic energy (head) for runaway speed guarantee;
– range of water temperatures;
– water quality analysis (chemical, biological, corrosive nature and suspended solids); and
– range of ambient temperatures and humidity (tropical or extreme cold environment needs to
be clearly defined).
– 12 – 61366-5 © IEC:1998(E)
3.4.3 Specified conditions
a) Modes of operation: As an extension to TD section 2.5, the Employer should provide
sufficient data to enable the Contractor to understand the Employer's intended mode(s) of
operation, e.g. base load, peaking or sluice operation. Data should include, wherever
possible, the anticipated number of start-stops per year and the capacity factor of the plant.
Special uses shall also be clearly identified such as spinning reserve, isolated and black
start operations, etc.
b) Power (P), Specific Hydraulic Energy (E) [Head (H)], and Discharge (Q): The specified
specific hydraulic energy (head) and discharge of the machine are determined from an
analysis of available discharge, specific hydraulic energy (head) of the plant and hydraulic
losses external to the machine with respect to statistical duration (refer to 2.3 to 2.6 of
IEC 61366-1). Relevant power can be established from a predetermined value efficiency.
If the range of specific hydraulic energy is wide, more than one specified value for E, Q and
P may need to be selected to define the operational range of the machine.
In the case of an unregulated turbine and if there are any limitations on maximum discharge
at any specific hydraulic energy (head), the Employer shall provide adequate data in the
technical specifications to enable the Contractor to optimize turbine design while respecting
these limitations.
c) Speed: The choice of speed of the unit has an impact on turbine, and generator costs, on
the setting of the turbine with respect to tailwater levels and on powerhouse costs.
If permitted by the project schedule, the approximate cost per meter of powerhouse setting
(see annex B, clause B.3), and the approximate cost per kVA for various possible speed
options for the generator should be specified by the Employer in the ITT (subsection 1.1.15)
so that the Tenderer may quote the turbine which best suits site conditions and its available
design.
In most cases, the project schedule dictates an early decision with respect to speed. Under
such conditions, discussions should be held with potential suppliers of turbines and
generators to fix a preferred speed; alternative proposals may be invited in the instructions
to Tenderers.
d) Direction of rotation: The direction should be specified clockwise or counter-clockwise
looking from the generator toward the turbine.
3.4.4 Generator characteristics
The specifications should state the principal characteristics of the generators to which the
turbines will be coupled. For example:
– capacity (kVA);
– power factor;
– frequency (normal and exceptional range);
– inertia or flywheel effect of generator;
– preferred speed (if established);
– preferred bearing arrangement (if established);
– approximate rotor diameter (if available).
3.4.5 Transient behaviour data
The Employer should, during preliminary design phase of the project and prior to turbine
selection, determine the various factors relating to power acceptance and power rejection by
the turbine. These factors may include:
– acceptable variation in electrical system frequency;
– inertia of the rotating parts or mechanical starting time;
– velocity of pressure waves (sound velocity in the water passages);

61366-5 © IEC:1998(E) – 13 –
– details of high-pressure and low-pressure conduits for the turbine;
– water starting time;
– turbine guide vane opening and closing times;
– transient pressure variations in the turbine;
– transient pressure variations in the turbine draft tube;
– limitation of sudden decrease of discharge with respect to surge control.
Transient data established by the Employer should be provided and those data which require
verification by the Contractor should be specified. Other data not specified by the Employer
may have to be established by the Contractor. (Refer to guarantees in 3.5.5 and 3.5.6.)
3.4.6 Stability of the system
The hydro-turbine control system should be specified in accordance with IEC 61362. The
performance of the hydro-turbine control system should be specified according to IEC 60308.
The Employer should furnish the information necessary to predict possible resonance in the
water passages of the power plant and in the unit. Admissible limits may be specified for
fluctuations of turbine shaft torque and of pressure in the draft tube.
3.4.7 Noise
Noise level limits may be legislated by national or local statutes. Noise abatement measures
may be the combined responsibility of the Employer and the Contractor. Reference should be
made by the Employer to ISO 3740 together with other standards, statutes or guides to
establish noise measurement and acceptance criteria. The limits and the means by which they
can be achieved should be specified in TD subsection 6.1.5.11.
3.4.8 Vibration
The specifications should require that the machine operates through its full range of specified
conditions without vibration which would be detrimental to its service life. Reference should be
made by the Employer to IEC 60944 together with suitable standards or guides to establish
deflection measurements and acceptance criteria. Limits of vibration may be established for
steady-state conditions and for normal transient regimes as criteria for final acceptance.
3.4.9 Sand erosion considerations
Risk of sand erosion may influence the design and operation of the hydraulic machine. In this
event, the technical specifications should indicate the content of suspended solids, their type,
hardness, size and shape. See annex H of IEC 61366-1.
3.4.10 Safety requirements
The Employer should state specific safety requirements which shall be met in the design of the
turbine. These requirements are, in addition to the general safety, related items outlined in 5.6
of IEC 61366-1.
3.5 Technical performance and other guarantees
3.5.1 General
Hydraulic performance guarantees for hydraulic machines are presented in clause 3 of
IEC 60041. The main guarantees outlined in Part 1, annex E of this guide, should be read in
conjunction with IEC 60041.
– 14 – 61366-5 © IEC:1998(E)
The main steady-state hydraulic performance guarantees (i.e. power, discharge, efficiency and
runaway speed) may be verified by model tests or by field acceptance tests. Guarantees may
be referred directly to the hydraulic performance of the model (without scale effect) or
alternatively to the hydraulic performance of the prototype computed from model tests with
allowance for scale effects (refer to IEC 60193).
The Employer should establish and specify the essential parameters on which the performance
guarantees are to be based. These parameters include plant specific hydraulic energy (plant
head) and energy losses external to the high-pressure and low-pressure reference sections of
the machine. The Employer should retain responsibility for specifying acceptable inlet and
outlet conditions of the machine and for co-ordination of the interaction between the machine
and the external waterways under transient and steady-state oscillating conditions.
In those cases where it is not possible to perform field acceptance tests under specified
conditions refer to IEC 60041.
The Employer should specify measurement methods and measurement uncertainties which are
contractually applied if different than those established by relevant IEC publications.
In addition to specifying the guaranteed performance provisions in the technical specification, it
is important that the Employer summarize these provisions in TD subsection 1.1.13 of the ITT.
Also, it is desirable that the manner in which Tenderers present and state their performance
guarantees be clearly specified.
The Employer should select the appropriate level and type of performance guarantees for the
machine taking into consideration the intended mode of operation and the importance of the
machine in the electrical system.
When it is necessary to include other aspects of the machine under performance guarantees
(such as stability, noise, and vibration), the Employer should include these provisions at the
end of this section taking into consideration that available data may not be sufficient, based on
extended experience. In any event, conditions under which guarantees are to be evaluated
shall be specified.
3.5.2 Guaranteed power
In specifying the guarantee for power, refer to TD subsection 6.1.4.3 of the specified
conditions, and state clearly the basis of the guarantee.
It is necessary in this subclause to establish the contractual obligations of the Contractor if the
guaranteed power is not met. The method(s) of measurements, method of comparison with
guarantees and application of IEC 60041 shall be defined.
3.5.3 Guaranteed minimum discharge
In some cases, it may be necessary to specify guaranteed requirements for a particularly low,
continuous and stable discharge. The Employer should indicate the expected duration of
operation and any special discharge conditions. The method of measurement should be
specified.
3.5.4 Guaranteed efficiency
The Employer shall establish and specify:
a) basis of guarantee; model or prototype;

61366-5 © IEC:1998(E) – 15 –
b) method proposed to measure guaranteed efficiency
– by model acceptance tests in Contractor's laboratory or in another laboratory acceptable
to both parties using test results with a mutually agreed step-up formula (see
IEC 60193), or
– by field acceptance tests of one or more prototype turbines (see IEC 60041);
c) Efficiency weighting formula to allow Tenderer to optimize the guaranteed efficiency in the
normal operating range of the turbine with respect to both power and specific hydraulic
energy (head), while taking into consideration the value specified by the Employer for gain
or loss in efficiency (refer to annex B of IEC 61366-1);
d) applicable codes (see 2.1 of IEC 61366-1);
e) measurement methods and preliminary estimated measurement uncertainties to be
contractually applied if different than those established by relevant IEC publications;
f) contractual consequences, if any, of the Contractor's failure to fulfil the guaranteed
efficiency or of Contractor exceeding the guaranteed efficiency (penalty or premium).
The technical data sheets of the tender forms should provide space for the Tenderer to record
the guaranteed weighted efficiency.
In large multi-unit projects which justify the expense, the Employer may choose to preselect
two or more competing Tenderers for the performance of turbine model tests at the Employer's
expense. In this event, the results of the model tests can be used in the final award of the
Contract to the successful Tenderer.
3.5.5 Guaranteed maximum/minimum momentary pressure
It is usual for the Contractor to guarantee momentary pressure even when there is no
contractual responsibility for complete design of the plant. (Refer to Part 1, annex E, E.2.6).
The Contractor should be required to calculate and guarantee the maximum momentary
pressure under load rejection from specified conditions (specified power and specified specific
hydraulic energy) and the most unfavourable transient conditions established by the Employer.
However, the Employer shall specify all relevant data because of the involvement and influence
of the electrical generator, speed regulator, and waterway system in the transient phenomenon
(see 3.4.5).
3.5.6 Guaranteed maximum momentary overspeed
The maximum momentary overspeed is the overspeed attained under the most unfavourable
transient conditions. Under certain conditions, it may exceed maximum steady-state runaway
speed. The maximum momentary overspeed should be guaranteed by the Contractor.
However, the Employer shall specify all relevant data because of the involvement and influence
of the electrical generator, speed regulator, and waterway system in the transient phenomenon
(see 3.4.5).
3.5.7 Guaranteed maximum steady-state runaway speed
The specifications should require that Contractor guarantees the maximum steady-state
runaway speed under the worst combination of conditions established by the Employer, for
example, maximum specific hydraulic energy (head) and physical maximum guide vane
opening for propeller turbines and worst off-cam condition for Kaplan turbines considering
variations in the plant cavitation factor. Taking into consideration powerhouse arrangement,
number and type of independent shut-off devices, loc
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