EN IEC 61362:2024

Guidelines to specification of hydraulic turbine governing systems

IEC 61362:2024 includes relevant technical data necessary to describe hydraulic turbine governing systems and to define their performance. It is aimed at unifying and thus facilitating the selection of relevant parameters in bidding specifications and technical bids. It will also serve as a basis for setting up technical guarantees. The scope of this standard is restricted to the turbine governing level. Additionally some remarks about the control loops of the plant level and about primary and secondary frequency control (see also Annex B) are made for better understanding without making a claim to be complete. Important topics covered are: - speed, power, water level, opening and flow (discharge) control for reaction and impulse-type turbines including double regulated machines; - means of providing actuating energy; - safety devices for emergency shutdown. To facilitate the setting up of specifications, this guide also includes data sheets, which are to be filled out by the customer and the supplier in the various stages of the project and the contract. Acceptance tests, specific test procedures and guarantees are outside the scope of the guide; those topics are covered by IEC 60308. This third edition cancels and replaces the second edition published in 2012. This edition includes the following significant technical changes with respect to the previous edition: adoption of parts of IEC 60308:2005 which deal with specification matters; introduction of several new technical topics; and overall editorial revision. Keywords: Hydraulic turbine, Hydraulic turbine governing systems.

Leitfaden zur Spezifikation der Regeleinrichtung von Wasserturbinen

Lignes directrices pour la spécification des systèmes de régulation des turbines hydrauliques

La IEC 61362:2024 contient les données techniques nécessaires pour décrire les systèmes de régulation des turbines hydrauliques et définir leurs performances. Elle a pour but d'unifier et ainsi de faciliter les spécifications des appels d'offres et les offres techniques. Elle servira également de base pour fixer les garanties techniques. Le domaine d'application de la présente norme est limité au niveau du régulateur turbine. En outre, des remarques sur les boucles de contrôle au niveau de la centrale ainsi que sur le réglage de fréquence primaire et secondaire (voir aussi l'Annexe B) apportent une meilleure compréhension sans avoir la prétention d'être exhaustives. Le guide traite les fonctions importantes suivantes: - les régulations de vitesse, puissance, niveau d'eau, ouverture et débit (décharge) des turbines à réaction et des turbines à action, y compris les machines à double régulation; - les moyens de production de l'énergie de manoeuvre; - les dispositifs de sécurité pour l'arrêt d'urgence, etc. Pour faciliter la rédaction des spécifications, ce guide inclut des formulaires de données à remplir par le client et par le fournisseur aux différentes étapes du projet et du contrat. Les essais de réception, les procédures d´essais spécifiques et les garanties ne sont pas traités par le guide mais par la CEI 60308. Cette troisième édition annule et remplace la seconde édition parue en 2012. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: prise en compte des paragraphes de la deuxième édition de l’IEC 60308 parue en 2005 qui traitent des questions de spécification; présentation de plusieurs nouveaux sujets techniques; et révision rédactionnelle complète. Mots clé: turbines hydrauliques, systèmes de régulation des turbines hydrauliques.

Smernice za specifikacijo sistemov za krmiljenje hidravličnih turbin (IEC 61362:2024)

Standard IEC 61362:2024 vsebuje ustrezne tehnične podatke, potrebne za opis sistemov za krmiljenje hidravličnih turbin in določitev njihove zmogljivosti. Njegov namen je združiti in s tem poenostaviti izbor ustreznih parametrov pri razpisnih specifikacijah in tehničnih ponudbah. Prav tako bo služil kot osnova za ureditev tehničnih jamstev. Področje uporabe tega standarda je omejeno na raven krmiljenja turbin. Poleg tega so za boljše razumevanje navedene nekatere opombe glede krmilnih zank na ravni naprave ter primarne in sekundarne kontrole frekvence (glej tudi dodatek B), vendar niso popolne. Zajete so naslednje pomembne teme:
– krmiljenje hitrosti, moči, ravni vode, odpiranja in pretoka (iztoka) za reakcijske in impulzne turbine, vključno s stroji z dvojnim uravnavanjem;
– načini zagotavljanja pogonske energije;
– varnostne naprave za izklop v sili.
Za lažjo določitev specifikacij vključujejo ta navodila tudi tehnične liste, ki jih stranka in dobavitelj izpolnjujeta v različnih fazah projekta in pogodbe. Preskusi sprejemljivosti, posebni preskusni postopki in jamstva ne spadajo na področje uporabe navodil; to je zajeto v standardu IEC 60308. Tretja izdaja razveljavlja in nadomešča drugo izdajo, objavljeno leta 2012. Ta izdaja v primerjavi s prejšnjo vključuje naslednje pomembne tehnične spremembe: sprejeti so bili deli standarda IEC 60308:2005 v zvezi s specifikacijo, uvedenih je bilo več novih tehničnih tem in izvedena je bila celovita uredniška revizija.

General Information

• Status: Published
• Publication Date: 24-Oct-2024
• ICS: 27.140 - Hydraulic energy engineering
• Technical Committee: CLC/SR 4 - Hydraulic turbines
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 25-Oct-2024
• Due Date: 01-Apr-2024
• Completion Date: 25-Oct-2024
• Ref Project: SIST EN IEC 61362:2024 - Guidelines to specification of hydraulic turbine governing systems (IEC 61362:2024)

Relations

• Replaces: EN 61362:2012 - Guide to specification of hydraulic turbine governing systems
• Effective Date: 18-Apr-2023

Overview

EN IEC 61362:2024 - "Guidelines to specification of hydraulic turbine governing systems (IEC 61362:2024)" provides a harmonized framework of technical data and specification guidance for hydraulic turbine governing systems. The third edition (2024) replaces EN 61362:2012, adopts parts of IEC 60308 relevant to specification, introduces new technical topics and an overall editorial revision. Its primary aim is to unify parameters used in bidding documents and technical offers and to serve as a basis for defining technical guarantees at the turbine governing level. Acceptance tests and guarantees are handled by IEC 60308 and are explicitly outside the scope.

Key Topics and Requirements

This guide concentrates on the turbine governing level and includes practical specification material such as customer/supplier data sheets to be filled during project stages. Important technical topics covered include:

• Control functions: speed, power (output), water level, guide-vane opening, and flow (discharge) control for reaction and impulse turbines, including double-regulated machines and pump-turbines.
• Control architecture: controller configurations (parallel/series), feed‑forward, bumpless mode transitions, optimization control, and interactions with plant‑level loops (including remarks on primary/secondary frequency control in Annex B).
• Servo and actuator systems: servo‑positioner configurations, dynamic characteristics, multiple actuator control and dual regulation (guide vanes + runner blades).
• Provision of actuating energy: systems with accumulators (pressure tanks, piston/bladder types), systems without accumulators (constant/variable flow), pumps, sump tanks and auxiliary equipment.
• Safety and protection: quick shutdown, emergency shutdown devices, overspeed protection, interlocks, tripping strategies and criteria.
• Instrumentation & modelling: speed, power and level measurement, signal transmission, modelling and digital simulation (including hardware-in-the-loop and personnel training considerations).
• Controller tuning & performance: PID parameters, permanent droop, governor insensitivity, tuning guidance and limitations.

Note: Acceptance test procedures, specific test methods and contractual guarantee formulation are referenced to IEC 60308.

Practical Applications

EN IEC 61362:2024 is intended to simplify and standardize specification and procurement activities and to reduce ambiguity in technical bidding. Typical practical uses:

• Preparing technical specification documents for new hydro units or retrofits
• Evaluating supplier technical bids and checking conformity with required governing performance
• Defining functional and safety requirements for turbine governors and actuators
• Supporting engineering design (control architecture, servo sizing, actuating energy systems) and simulation-based commissioning
• Informing contract clauses and setting up data-sheet driven deliverables between customer and supplier

Who should use this standard

• Hydro plant engineers and control system designers
• Project and procurement managers preparing tender documents
• Turbine manufacturers and control suppliers preparing technical bids
• Utilities and asset owners defining guarantees and acceptance criteria
• Testing and commissioning teams using simulation and HIL methods

Related Standards

• IEC 60308 - Hydraulic turbines: testing of governing systems (referenced for tests and guarantees)
• IEC 61131‑2 - Programmable controllers (equipment requirements and tests)
• IEC 60193 - Hydraulic turbine/generator electromechanical characteristics (bibliography / related reference)

Keywords: Hydraulic turbine, Hydraulic turbine governing systems, turbine governor, servo‑positioner, pump‑turbine, actuator energy, IEC 61362.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2024
Smernice za specifikacijo sistemov za krmiljenje hidravličnih turbin (IEC
61362:2024)
Guidelines to specification of hydraulic turbine governing systems (IEC 61362:2024)
Leitfaden zur Spezifikation der Regeleinrichtung von Wasserturbinen (IEC 61362:2024)
Lignes directrices pour la spécification des systèmes de régulation des turbines
hydrauliques (IEC 61362:2024)
Ta slovenski standard je istoveten z: EN IEC 61362:2024
ICS:
27.140 Vodna energija Hydraulic energy engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61362

NORME EUROPÉENNE
EUROPÄISCHE NORM October 2024
ICS 27.140 Supersedes EN 61362:2012
English Version
Guidelines to specification of hydraulic turbine governing
systems
(IEC 61362:2024)
Lignes directrices pour la spécification des systèmes de Leitfaden zur Spezifikation der Regeleinrichtung von
régulation des turbines hydrauliques Wasserturbinen
(IEC 61362:2024) (IEC 61362:2024)
This European Standard was approved by CENELEC on 2024-10-22. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61362:2024 E
European foreword
The text of document 4/500/FDIS, future edition 3 of IEC 61362, prepared by TC 4 "Hydraulic turbines"
was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-10-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-10-31
document have to be withdrawn
This document supersedes EN 61362:2012 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61362:2024 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 60193 NOTE Approved as EN IEC 60193
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60308 - Hydraulic turbines - Testing of governing EN IEC 60308 -
systems
IEC 61131-2 - Industrial-process measurement and EN 61131-2 -
control - Programmable controllers - Part 2:
Equipment requirements and tests

IEC 61362 ®
Edition 3.0 2024-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Guidelines to specification of hydraulic turbine governing systems

Lignes directrices pour la spécification des systèmes de régulation des turbines

hydrauliques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.140  ISBN 978-2-8322-9577-9

– 2 – IEC 61362:2024 © IEC 2024
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 10
3.1 General terms and definitions . 11
3.2 Terms and definitions related to control levels, control modes and
operational modes . 11
3.3 Terms and definitions from control theory . 12
3.4 Subscripts and prefixes . 13
3.5 Terms and definitions related to the plant and the units . 13
3.6 Terms and definitions related to the governing system . 16
4 Governing system structure . 23
4.1 General . 23
4.2 Main control functions . 24
4.2.1 General . 24
4.2.2 Speed control . 24
4.2.3 Power output control . 24
4.2.4 Opening control . 24
4.2.5 Water level control . 25
4.2.6 Flow control . 25
4.3 Configurations of combined controllers . 25
4.3.1 General . 25
4.3.2 Parallel structure . 25
4.3.3 Series structures . 26
4.4 Special control functions . 26
4.4.1 Feed forward control . 26
4.4.2 Surge tank level or pressure feedback . 27
4.5 Pump-turbine control . 28
4.5.1 General . 28
4.5.2 Conventional pump-turbine control . 28
4.5.3 Variable speed pump-turbine control . 28
4.6 Manual control . 30
4.7 Linearization . 30
4.8 Limitation functions . 30
4.9 Bumpless control modes transition . 31
4.10 Optimization control . 31
5 Functional performance . 31
5.1 General . 31
5.2 Modelling and digital simulation . 32
5.2.1 General . 32
5.2.2 Water passages . 33
5.2.3 Turbine, generator, electrical grid . 33
5.2.4 Control concept . 33
5.2.5 Hardware-in-the-loop simulation . 34
5.2.6 Personnel training . 34
5.2.7 Inaccuracy of plant simulators . 34

IEC 61362:2024 © IEC 2024 – 3 –
5.3 Characteristic parameters for PID-controllers . 35
5.3.1 General . 35
5.3.2 Permanent droop . 35
5.3.3 Proportional action coefficient K , integral action time T , and derivative
P I
action time T . 35
D
5.3.4 Tuning of turbine governing systems . 36
5.4 Other parameters of the governing systems . 37
5.4.1 Command signal adjustments for controlled variables (speed, power
output, etc.) and load limiter . 37
5.4.2 Governor insensitivity i /2 . 37
x
5.4.3 Dynamic characteristics of servo-positioner . 37
5.4.4 Parameters of servo-positioner . 39
5.4.5 Servo-positioner non-linearity by kinematics . 40
6 Servo positioner configurations . 40
6.1 Servo-positioners . 40
6.2 Configurations of servo-positioners . 41
6.3 Multiple actuator control . 41
6.3.1 General . 41
6.3.2 Parallel structure . 42
6.3.3 Series structure . 42
6.3.4 Individual control . 42
6.4 Dual regulation of turbines with controllable guide vane and runner blade
angles . 43
6.5 Dual control of turbines with needles and deflectors . 43
6.6 Other relationships . 43
7 Instrumentation . 43
7.1 General . 43
7.2 Rotational speed . 44
7.3 Power output . 44
7.4 Water level . 44
7.5 Actuator position (stroke) . 44
7.6 Signal transmission from electronic transmitters . 44
8 Safety functions and devices . 44
8.1 General . 44
8.2 Quick shutdown and emergency shutdown . 44
8.2.1 General . 44
8.2.2 Tripping actions . 45
8.2.3 Servomotor shutdown initiating devices . 45
8.2.4 Tripping criteria . 45
8.2.5 Tripping strategies . 45
8.3 Overspeed protection device . 45
8.4 Interlocks . 45
9 Provision of actuating energy. 46
9.1 General . 46
9.2 System with an accumulator . 46
9.2.1 Pressure tank (air-oil accumulator) . 46
9.2.2 Piston accumulators . 48
9.2.3 Bladder accumulators . 48

– 4 – IEC 61362:2024 © IEC 2024
9.2.4 Other systems . 48
9.2.5 Pumps for accumulator systems . 48
9.2.6 Oil sump tanks . 49
9.2.7 Auxiliary equipment . 49
9.2.8 Provision of pressurized gas . 49
9.3 Systems without accumulator . 50
9.3.1 Constant flow systems . 50
9.3.2 Variable flow systems . 50
9.4 Direct electric positioner . 51
9.5 Recommendation for hydraulic fluid selection . 51
10 Operational transitions. 51
10.1 Start-up and synchronization. 51
10.2 Normal shutdown . 52
10.3 Sudden load rejection . 52
10.4 Other operational transitions . 53
11 Supplementary equipment . 53
11.1 Measures to reduce pressure variations . 53
11.2 Surge control . 53
11.3 Equipment and measures to lower the speed rise . 54
11.4 Joint control . 54
11.5 Braking . 54
11.6 Synchronous condenser mode of operation . 54
12 Considerations for the electronic governor . 55
12.1 Equipment requirements . 55
12.2 Power supply recommendations . 55
13 How to apply the recommendations . 55
Annex A (normative) Simplified differential equations and transfer functions of

idealized PID-control functions . 68
Annex B (informative) Grid frequency control . 70
B.1 General . 70
B.2 Power equilibrium and grid frequency . 70
B.2.1 Power equilibrium . 70
B.2.2 Grid frequency . 70
B.3 Primary frequency control . 70
B.3.1 Primary frequency control performed by generating units . 70
B.3.2 Droop of a generating unit . 71
B.4 Secondary frequency control . 72
Annex C (informative) Role of governing systems for stability in interconnected grid
operation . 73
C.1 General . 73
C.2 Stability of the unit with respect to the water hydraulic system . 73
C.3 Stability of the unit with respect to the electrical power system . 73
C.3.1 General . 73
C.3.2 Power oscillations due to the electrical power system . 74
C.3.3 Power oscillations due to pressure fluctuations in hydraulic machines . 74
C.3.4 Conclusion . 75
Annex D (informative) Quick shutdown and emergency shutdown . 76
D.1 General . 76

IEC 61362:2024 © IEC 2024 – 5 –
D.2 Alternative example I . 76
D.2.1 General . 76
D.2.2 Quick shutdown . 76
D.2.3 Emergency shutdown. 77
D.2.4 Summary table and combined tripping cases . 78
D.3 Alternative example II . 79
Bibliography . 80

Figure 1 – Turbine control transmission ratio . 15
Figure 2 – Controlled system self-regulation factor . 15
Figure 3 – Controlled variable range . 17
Figure 4 – Permanent droop . 17
Figure 5 – Proportional action coefficient and integral action time . 18
Figure 6 – Derivative time constant . 19
Figure 7 – Dead band . 20
Figure 8 – Minimum servomotor opening/closing time . 20
Figure 9 – Time constants of the servomotor/servo-valve combination . 21
Figure 10 – Servo-positioner inaccuracy . 22
Figure 11 – Governing system dead time . 23
Figure 12 – Governing system with speed and power output control functions in
parallel . 26
Figure 13 – Governing system with speed control function and water level control
function in parallel . 26
Figure 14 – Governing system with power output and speed control functions in series . 26
Figure 15 – Schematic diagram of a turbine governing system with feed forward . 27
Figure 16 – Schematic diagram of a turbine governing system with an additional
pressure feedback compensation control function . 28
Figure 17 – Governor function in conventional pump mode . 28
Figure 18 – Governor function of variable speed pumped storage systems in pump
mode . 29
Figure 19 – Governor function of variable speed pumped storage systems in turbine

mode with power output based control . 29
Figure 20 – Governor function of variable speed pumped storage systems in turbine
mode with rotating speed based control . 29
Figure 21 – Servo-positioner control loop – simplified dynamic model with P-controllers . 38
Figure 22 – Servo-positioner control loop – simplified dynamic model . 38
Figure 23 – Time step response and frequency response of the output of the servo-
positioner . 39
Figure 24 – Servo-positioner block diagram . 41
Figure 25 – Parallel structure with defined functional relation and an additional signal
superimposition . 42
Figure 26 – Series structure with defined functional relation and additional signal
superimposition . 42
Figure 27 – Structure with different set-points for each servo-positioner . 42
Figure 28 – Pressure tank content and pressure ranges . 46
Figure 29 – Open-circuit system . 50
Figure 30 – Start-up speed curve up to synchronization . 52

– 6 – IEC 61362:2024 © IEC 2024
Figure 31 – Load rejection . 53
Figure A.1 – Idealized PID in pure parallel structure . 68
Figure A.2 – Idealized PID alternative representation . 68
Figure B.1 – Example of principle schematic functional diagram of a unit with a turbine
governing system using an idealized PID control function with a frequency-power

droop . 71
Figure B.2 – Behaviour of two units with different governor permanent droop values . 72

Table 1 – Unit and plant categories . 55
Table D.1 – Alternative I – Summary of cases for quick shut-down and emergency
shut-down . 78
Table D.2 – Alternative II – Summary of cases for quick shut-down and emergency
shut-down . 79

IEC 61362:2024 © IEC 2024 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDELINES TO SPECIFICATION OF
HYDRAULIC TURBINE GOVERNING SYSTEMS

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 61362 has been prepared by IEC technical committee 4: Hydraulic turbines. It is an
International Standard.
This third edition cancels and replaces the second edition published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) adoption of parts of IEC 60308:2005 which deal with specification matters;
b) introduction of several new technical topics;
c) overall editorial revision.

– 8 – IEC 61362:2024 © IEC 2024
The text of this document is based on the following documents:
Draft Report on voting
4/500/FDIS 4/509/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

IEC 61362:2024 © IEC 2024 – 9 –
INTRODUCTION
While a standard for the testing of hydraulic turbine governing systems had been existing for a
very long time (IEC 60308 published in 1970) , guidelines for the specification of hydraulic
turbine governing systems were missing until 1998. The need for such guidelines became more
and more urgent with the fast development and the new possibilities especially of the digital
components of the governor.
While the first edition was written more or less as a supplement to the already existing guide
for testing, the objective of the second edition was to be the leading guide with respect to turbine
governing systems.
The second edition of this document took into account the experience with the guide until 2012
as well as the progress in the state of the art of the underlying technologies.
This third edition was developed together with the third edition of the standard for the testing of
hydraulic turbine governing systems (IEC 60308) in order to harmonize their contents and their
publishing dates.
Furthermore, the standards are kept open for state of the art by introducing new topics and
harmonizing the structure as well as the terms and definitions for both standards.

___________
IEC 60308:1970, International code for testing of speed governing systems for hydraulic turbines. This publication
was withdrawn and replaced with IEC 60308:2005.

– 10 – IEC 61362:2024 © IEC 2024
GUIDELINES TO SPECIFICATION OF
HYDRAULIC TURBINE GOVERNING SYSTEMS

1 Scope
This document includes relevant technical data used to describe hydraulic turbine governing
systems and to define their performance. It is aimed at unifying and thus facilitating the selection
of relevant parameters in bidding specifications and technical bids. It serves also as a basis for
setting up technical guarantees.
The scope of this document is restricted to the turbine governing level. Additionally some
remarks about the control loops of the plant level and about interactions with the electrical grid
in case of primary and secondary frequency control (see also Annex B and Annex C) are made
for better understanding without making a claim to be complete.
Important topics covered by the guidelines are:
– speed, power, water level, opening and flow (discharge) control for reaction and impulse-
type turbines including double regulated machines;
– means of providing actuating energy;
– safety devices for emergency shutdown, etc.
To facilitate the setting up of specifications, these guidelines also include data sheets, which
are filled out by the customer and the supplier in the various stages of the project and the
contract.
Acceptance tests and specific test procedures are outside the scope of this document; those
topics are covered by IEC 60308.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60308, Hydraulic turbines – Testing of control systems
IEC 61131-2, Industrial-process measurement and control – Programmable controllers – Part 2:
Equipment requirements and tests
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp

IEC 61362:2024 © IEC 2024 – 11 –
3.1 General terms and definitions
3.1.1
turbine governing system
technical equipment governing the opening (guide vane, runner blade, needle, deflector
position) of hydraulic turbines
Note 1 to entry: At the present state of the art, the turbine governing system consists of an oil hydraulic and an
electronic part, the "oil hydraulic governor" and the "electronic governor" and an interface between both, the
electro/hydraulic converter.
3.1.2
controlled system
system controlled by the actuators of the governing system consisting of the hydraulic turbine,
its water supply and discharge passages, the generator with voltage regulator and the electric
power grid to which it is connected
3.2 Terms and definitions related to control levels, control modes and operational
modes
3.2.1
control levels
3.2.1.1
turbine governing level
control functions directly related to the governing system of a single turbine
Note 1 to entry: The following control modes are related to the turbine governing level:
– speed control;
– power output control;
– water level control;
– opening control;
– flow control (the term flow used in this document has the same meaning as the term discharge).
3.2.1.2
unit control level
control functions directly related to the overall control of a single unit (turbine, generator, unit
auxiliaries) including turbine governing, voltage regulation, start-stop-sequencing etc.
3.2.1.3
plant control level
control functions related to the overall control of a whole plant including the control of several
units
Note 1 to entry: In automatic unit and plant control operation, the turbine governing system gets its modes and set-
points from the unit and plant control level.
3.2.1.4
grid control level
control functions related to the overall control of the grid as a whole
Note 1 to entry: If applicable the turbine governing system participates either by primary or by secondary frequency
control, or both (see Annex B).
3.2.2
control modes at the turbine governing level
3.2.2.1
speed control
mode of the governing system dealing with the control of the speed of the turbine

– 12 – IEC 61362:2024 © IEC 2024
3.2.2.2
power output control
mode of the governing system dealing with the control of the power output of the generator
3.2.2.3
water level control
mode of the governing system dealing with the control of the water level of the headwater
reservoir
3.2.2.4
opening control
mode of the governing system dealing with the control of the position of the main actuator(s) of
the turbine
3.2.2.5
flow control
mode of the governing system dealing with the control of the flow through the turbine
3.2.3
main operation modes
3.2.3.1
no-load operation
mode of the governing system when the unit is not connected to a grid
3.2.3.2
island operation
operation of a generating unit that is interconnected with a relatively small number of other
generating units
Note 1 to entry: Such a small number can occur after inadvertent tripping of circuit breakers that interconnect the
island with a large interconnected power system.
3.2.3.3
isolated operation
specific case of islanded operation consisting of a single generating unit
3.2.3.4
grid operation
mode of the governing system when the unit is connected to a stable grid
3.3 Terms and definitions from control theory
3.3.1
differential equation
equation describing the dynamic system behaviour in the time-domain, as shown in Annex A
3.3.2
transient response
system response (output) to a step change of the input
3.3.3
frequency response
for a linear time-variant system with a sinusoidal input variable in steady-state the ratio of the
phasor of the output variable to the phasor of the corresponding input variable, represented as
a function of the angular frequency ω
Note 1 to entry: The frequency response coincides with the transfer function taken on the imaginary axis of the
complex plane.
IEC 61362:2024 © IEC 2024 – 13 –
3.3.4
transfer function
for a linear time-invariant system the ratio of the Laplace transformation of an output variable
to the Laplace transform of the corresponding input variable, with all initial values equal to zero
Note 1 to entry: The Laplace operator s is the complex variable of Laplace transform, only used for transfer functions
in the frequency domain.
3.4 Subscripts and prefixes
Sub- Subscript/prefix Definition Symbol Unit
clause related to
3.4.1 rated subscript indicating the rated operation point of the system r –
3.4.2 maximum subscript indicating maximum or minimum values of any max. –
minimum term min.
3.4.3 deviation Prefix indicating the deviation of any value from a defined ∆ –
value (in case of linearization the defined value is the
steady-state value)
3.4.4
...