SIST EN 61362:2012

SLOVENSKI STANDARD
01-oktober-2012
9RGLOR]DVSHFLILFLUDQMHVLVWHPRY]DNUPLOMHQMHKLGUDYOLþQLKWXUELQ
Guide to specification of hydraulic turbine governing systems
Leitfaden zur Spezifikation der Regeleinrichtung von Wasserturbinen
Guide pour la spécification des systèmes de régulation des turbines hydrauliques
Ta slovenski standard je istoveten z: EN 61362:2012
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 61362
NORME EUROPÉENNE
August 2012
EUROPÄISCHE NORM
ICS 27.140 Supersedes EN 61362:1998

English version
Guide to specification of hydraulic turbine governing systems
(IEC 61362:2012)
Guide pour la spécification des systèmes Leitfaden zur Spezifikation der
de régulation des turbines hydrauliques Regeleinrichtung von Wasserturbinen
(CEI 61362:2012) (IEC 61362:2012)

This European Standard was approved by CENELEC on 2012-05-25. 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, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61362:2012 E
Foreword
The text of document 4/270/FDIS, future edition 2 of IEC 61362, prepared by IEC/TC 4 "Hydraulic
turbines" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
(dop) 2013-02-28
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2015-05-25
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61362:1998.

This technical revision takes into account the experience with the guide during the last decade as well
as the progress in the state of the art of the underlying technologies.

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
Endorsement notice
The text of the International Standard IEC 61362:2012 was approved by CENELEC as a European
Standard without any modification.

- 3 - EN 61362:2012
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60050-351 2006 International Electrotechnical Vocabulary - -
(IEV) -
Part 351: Control technology
IEC 60068-2-6 2007 Environmental testing - EN 60068-2-6 2008
Part 2-6: Tests - Test Fc: Vibration
(sinusoidal)
IEC 60068-2-27 2008 Environmental testing - EN 60068-2-27 2009
Part 2-27: Tests - Test Ea and guidance:
Shock
IEC 60308 2005 Hydraulic turbines - Testing of control EN 60308 2005
systems
IEC 61000-4-1 2006 Electromagnetic compatibility (EMC) - EN 61000-4-1 2007
Part 4-1: Testing and measurement
techniques - Overview of IEC 61000-4 series

CISPR 11 2009 Industrial, scientific and medical equipment - EN 55011 2009
(mod) Radio-frequency disturbance characteristics
- Limits and methods of measurement

ISO 3448 1992 Industrial liquid lubricants - ISO viscosity - -
classification
IEC 61362 ®
Edition 2.0 2012-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Guide to specification of hydraulic turbine governing systems

Guide pour la spécification des systèmes de régulation des turbines

hydrauliques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 27.140 ISBN 978-2-8322-0057-5

– 2 – 61362 © IEC:2012
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references. 8
3 Terms, definitions, symbols and units . 9
3.1 General terms and definitions . 9
3.2 Terms and definitions related to control levels and control modes . 9
3.3 Terms and definitions from control theory . 9
3.4 Subscripts and prefixes . 10
3.5 Terms and definitions related to the plant and the machines . 10
3.6 Terms and definitions relating to the governing system . 11
4 Control structure . 18
4.1 General . 18
4.2 Main control functions . 18
4.2.1 General . 18
4.2.2 Speed control . 19
4.2.3 Power output control . 19
4.2.4 Opening control . 19
4.2.5 Water level control . 19
4.2.6 Flow control . 20
4.3 Configurations of combined control systems . 20
4.3.1 General . 20
4.3.2 Parallel structure. 20
4.3.3 Series structures . 21
4.3.4 Other configurations . 22
4.4 Configurations of servo-positioners . 23
4.5 Multiple control . 23
4.5.1 General . 23
4.5.2 Parallel structure. 24
4.5.3 Series structure . 24
5 Performance and components of governing systems . 24
5.1 General . 24
5.2 Modeling and digital simulation . 25
5.3 Characteristic parameters for PID-controllers . 26
5.3.1 General . 26
5.3.2 Permanent droop b . 27
p
5.3.3 Proportional action coefficient K , integral action time T , and
p I
derivative action time T . 27
D
5.4 Other parameters of the governing systems . 28
5.4.1 Command signal adjustments for controlled variables (speed, power
output, etc.) and load limiter . 28
5.4.2 Governor insensitivity i /2 . 28
x
5.4.3 Parameters of servo-positioner . 29
5.5 Functional relationship between servo-positioners . 30
5.5.1 Dual regulation of turbines with controllable guide vane and runner
blade angles . 30

61362 © IEC:2012 – 3 –
5.5.2 Dual control of turbines with needles and deflectors . 31
5.5.3 Multiple control . 31
5.5.4 Other relationships . 31
5.6 Actual signal measurement . 31
5.6.1 General . 31
5.6.2 Rotational speed . 32
5.6.3 Power output . 32
5.6.4 Water level . 32
5.6.5 Actuator position (stroke) . 32
5.6.6 Signal transmission from electronic transmitters . 32
5.7 Manual control . 33
5.8 Linearization . 33
5.9 Follow-up controls . 34
5.10 Optimization control . 34
5.11 Monitoring parallel positioning of amplifiers . 34
5.12 Provision of actuating energy . 34
5.12.1 General . 34
5.12.2 System with an accumulator . 35
5.12.3 Systems without accumulator . 38
5.12.4 Direct electric positioner . 39
5.12.5 Recommendation for hydraulic fluid selection . 40
5.13 Power supply for electronic control systems . 40
5.14 Operational transitions . 40
5.14.1 Start-up and synchronization . 40
5.14.2 Normal shutdown . 41
5.14.3 Sudden load rejection . 41
5.14.4 Other operational transitions . 42
5.15 Safety devices/circuits . 42
5.15.1 General . 42
5.15.2 Quick shutdown and emergency shutdown . 42
5.15.3 Overspeed protection device . 43
5.15.4 Interlocks . 43
5.16 Supplementary equipment . 43
5.16.1 Measures to reduce pressure variations . 43
5.16.2 Surge control . 43
5.16.3 Equipment and measures to lower the speed rise . 44
5.16.4 Central flow rate control in river power station systems . 44
5.16.5 Brakes . 44
5.16.6 Synchronous condenser mode of operation . 45
5.17 Environmental suitability of governor components . 45
5.17.1 Vibration and shock resistance . 45
5.17.2 Temperature and humidity . 45
5.18 Electromagnetic compatibility . 45
6 How to apply the recommendations . 45
Annex A (normative) Simplified differential equations and transfer functions of idealized
PID-controllers . 58
Annex B (informative) Grid frequency control . 60
Annex C (informative) Quick shutdown and emergency shutdown . 63

– 4 – 61362 © IEC:2012
Figure 1 – Controlled variable range . 12
Figure 2 – Permanent droop . 12
Figure 3 – Proportional action coefficient and integral action time . 13
Figure 4 – Derivative time constant . 14
Figure 5 – Dead band . 15
Figure 6 – Minimum servomotor opening/closing time . 16
Figure 7 – Time constant of the servo-positioner . 16
Figure 8 – Servo-positioner inaccuracy . 17
Figure 9 – Control system dead time . 17
Figure 10 – Control system with speed and power output controllers in parallel . 21
Figure 11 – Control system with speed controller and power command signal in parallel . 21
Figure 12 – Control system with speed controller and water level controller in parallel . 21
Figure 13 – Governing system with power output and speed controller in series . 22
Figure 14 – Governing system with water level controller and speed controller in series . 22
Figure 15 – Power output control via the speed controller . 22
Figure 16 – Water level controller without speed controller . 23
Figure 17 – Parallel structure with defined functional relation and an additional signal
superimposition . 24
Figure 18 – Series structure with defined functional relation and additional signal
superimposition . 24
Figure 19 – Time step response and frequency response of the amplifier output Y/Y
max
to a displacement input s . 30
v
Figure 20 – Pressure tank content and pressure ranges . 35
Figure 21 – Open-circuit system . 39
Figure 22 – Start-up speed curve up to synchronization . 41
Figure 23 – Load rejection . 42
Figure A.1 – Idealized PID in pure parallel structure. 59
Figure A.2 – Idealized PID alternative representation . 59
Figure B.1 – Example of principle schematic functional diagram of a unit with a turbine

governing system using an idealized PID controller with a power droop . 61
Figure B.2 – Behaviour of two units with different governor permanent droop values . 62

Table C.1 – Alternative I – Summary of cases for quick shut-down and emergency shut-
down . 65
Table C.2 – Alternative II – Summary of cases for quick shut-down and emergency shut-
down . 66

61362 © IEC:2012 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDE 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 in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). 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. 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 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 IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61362 has been prepared by IEC technical committee 4: Hydraulic
turbines.
This second edition cancels and replaces the first edition published in 1998. It is a technical
revision. It takes into account the experience with the guide during the last decade as well as
the progress in the state of the art of the underlying technologies.
The text of this standard is based on the following documents:
FDIS Report on voting
4/270/FDIS 4/272/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – 61362 © IEC:2012
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
61362 © IEC:2012 – 7 –
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) , a guide for the specification of hydraulic turbine
governing systems was missing until 1998. The need for such a guide became more and more
urgent with the fast development and the new possibilities especially of the digital components
of the governor.
The current second edition of the guide takes into account the experience with the guide during
the last decade as well as the progress in the state of the art of the underlying technologies.
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 is to be the leading guide with respect to turbine
governing systems.
________
IEC 60308:1970, International code for testing of speed governing systems for hydraulic turbines. This
publication was withdrawn and replaced by IEC 60308:2005.

– 8 – 61362 © IEC:2012
GUIDE TO SPECIFICATION OF HYDRAULIC TURBINE
GOVERNING SYSTEMS
1 Scope
This International Standard 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 by the guide 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, 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.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
IEC 60050-351:2006, International Electrotechnical Vocabulary – Part 351: Control technology
IEC 60068-2-6:2007, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-27:2008, Environmental testing – Part 2-27: Tests – Test Ea and guidance: Shock
IEC 60308:2005, Hydraulic turbines – Testing of control systems
IEC 61000-4-1:2006, Electromagnetic compatibility (EMC) – Part 4-1: Testing and
measurement techniques – Overview of IEC 61000-4 series
CISPR 11:2009, Industrial, scientific and medical equipment – Radio-frequency disturbance
characteristics – Limits and methods of measurement
ISO 3448:1992, Industrial liquid lubricants – ISO viscosity classification

61362 © IEC:2012 – 9 –
3 Terms, definitions, symbols and units
For the purposes of this document, the following terms and definitions apply.
NOTE This guide uses as far as possible the terms and definitions of IEC 60050-351. For clarification, the
simplified differential equations and transfer functions of the idealized PID-controllers as used in this guide are
given in Annex A. Additional reference is made to IEC 60308 for purposes of tests of governing systems.
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".
3.2 Terms and definitions related to control levels and control modes
3.2.1
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 guide has the same meaning as the term discharge).

Note 2 to entry 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 Annex B) are
made for better understanding without making a claim to be complete.

3.2.2
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.
3.2.3
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
setpoints from the unit and plant control level.
3.2.4
grid control level
control functions related to the overall control of the grid as a whole
Note 1 to entry If required the turbine governing system participates in grid control over the primary and/or
secondary frequency control mode (see Annex B).
3.3 Terms and definitions from control theory
3.3.1
differential equation
equation describing the dynamic system behavior in the time-domain, as shown in Annex A

– 10 – 61362 © IEC:2012
3.3.2
transient response
system response (output) to a step change of the input
3.3.3
frequency response
dynamic response of the linearized system to a sinusoidal change of the input signal derived
from the differential equation by applying the Fourier transformation
3.3.4
transfer function
dynamic response of the linearized system to an arbitrary variation of the input signal derived
from the differential equation by applying the Laplace transformation
3.4 Subscripts and prefixes
Sub- Term Definition Symbol Unit
clause
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 term max. –
min.
minimum
3.4.3 deviation deviation of any term from a steady-state value –
∆
3.4.4 guide vanes subscript associating a quantity to guide vane position ga –
3.4.5 runner subscript associating a quantity to runner blade position ru –
3.4.6 nozzle subscript associating a quantity to needle position ne –
3.4.7 Deflector subscript associating a quantity to deflector position de –

3.5 Terms and definitions related to the plant and the machines
Sub-
Term Definition Symbol Unit
clause
–1
3.5.1 specific energy of hydraulic water available between the high-
specific energy J ⋅ kg
E
of machine and low-pressure side sections of the machine
3.5.2 m
turbine head H =E/g definition of E, see 3.5.1
H
g = acceleration due to gravity
–2
= 9,81 m⋅s (at sea level)
3.5.3 flow volume of water per unit time flowing through any section in 3 –1
m ⋅ s
Q
the system
–1  a
3.5.4 rotational number of revolutions per unit time s
n
speed
3.5.5 frequency cycles per second f Hz
3.5.6 generator power measured at generator terminals W
generator P
G
power output
3.5.7 moment of inertia for calculation of fly-wheel effect.
moment of 2
kg ⋅ m
I
2 2
inertia of mass I = M D /4 = MR

(M = mass, D = diameter of gyration,
R = radius of gyration)
a
The unit rpm is frequently used.

61362 © IEC:2012 – 11 –
3.6 Terms and definitions relating to the governing system
Sub-
Term Definition Symbol Unit
clause
3.6.1 controlled variable which has to be controlled as speed n, output P ,
G
water level h, servoposition opening y, flow Q:
variable
– absolute, dimensional value X var.
–
– relative deviation from a steady-state x
value, x = ∆X/X –
r
x –
rotational speed
n
x –
power output
p
x –
water level
h
x –
opening
y
flow x –
q
3.6.2 command a signal which can be set by an external adjustment:
signal
– absolute, dimensional value var.
C
– relative deviation from a steady-state value, c = ∆C/C c –
r
c –
rotational speed
n
power output c –
p
water level c –
h
opening c _
y
flow c _
q
3.6.3 servomotor stroke of the main servomotor which moves the guide
vane/runner blades/needles/deflectors
stroke
– absolute value Y m
y –
– relative deviation from a steady-state value, y = ∆Y/Y
max
Note 1 to entry The effective max. servomotor stroke Y
max
has to be defined between customer and supplier.
3.6.4 adjusting range for the setting of a controlled variable
controlled
variable range (rotational speed in speed control, or water level in level
control) with an average setting of the permanent droop, if
X –
max
applicable (see 3.6.8 and 5.3.2):
X –
min
– maximum value of the controlled variable
for Y/Y = 0
max
– minimum value of the controlled variable
for Y/Y = 1,0
max
SEE: Figure 1
– 12 – 61362 © IEC:2012
X
X
max.
Y
Y
max
1,0
X
min
IEC  383/12
Figure 1 – Controlled variable range

Sub-
Term Definition Symbol Unit
clause
3.6.5 output signal at the electronic governor = input signal of the
electronic
following servo-positioner
governor output
signal
Relative deviation from a steady-state value s –
3.6.6 output signal of output signal of a pilot servo-positioner = input signal of
the following main servo-positioner
a pilot servo-
positioner
Relative deviation from a steady-state value s –

v
3.6.7 droop graph a graph showing the relationship between a relative controlled
variable (speed n/n , or in some cases water level H/H ) as a
r r
function of the relative servomotor stroke or the relative power
output under steady-state conditions
SEE: Figure 2
X
X
r
b
s
b
p
Y P
,
Y P
1,0 max r
IEC  384/12
Figure 2 – Permanent droop
61362 © IEC:2012 – 13 –
Sub- Term Definition Symbol Unit
clause
3.6.8 permanent slope of the droop graph (see Figure 2):
droop
– at a specific point of operation, b %
p
– defined by the end values of the droop graph %
b
s
3.6.9 proportional proportional amplification, defined by the step response of an K –
p
idealized PID-controller with b = 0, K = 0 and input signal x = 1
action
p D
a
SEE: Figure 3
coefficient
a
In accordance with IEC 60050-351.

s or Y (PI behaviour)
K
p
t
T = T ⋅ K
i I p
IEC  385/12
Figure 3 – Proportional action coefficient and integral action time

– 14 – 61362 © IEC:2012
Sub-
Term Definition Symbol Unit
clause
3.6.10 integral action time constant of the integral action of an idealized PID- T s
I
a
time controller. The reset time T in parallel structured PID-
i
controllers is defined by T = T ⋅ K and K /T corresponds to

i I p p i
the slope of the controller step response curve with b = 0,

p
K = 0 and input signal x = 1
D
SEE: Figure 3
b
3.6.11 derivative time constant of the derivative action of an idealized PID- T s

D
action time controller. The transfer function (T ⋅ p) can practically be
D
realized only approximately by a DT transfer function, i.e. a

c
derivative term multiplied by a first-order lag element :
K ⋅ T ⋅ p
1D 1D
1 + T ⋅ p
1D
The step response of such a transfer function of an idealized
PID-controller, the proportional and integral term being zero, is
shown in Figure 4.
For small values of T the following approximation applies:
1D
T = K ⋅ T
D 1D 1D
a
Reset time can also be defined by T = K /K with integral action coefficient K = 1/T (see IEC 60050-351).

i p I I I
b
Rate time is defined in parallel structured PID-controllers by T = K /K , with derivative action coefficient

d D p
K = T (see IEC 60050-351).
D D
c
Realization also by second-order lag element possible.

s or Y (DT behaviour)
0,63 K
D
K
1D
t
T
1D
IEC  386/12
Figure 4 – Derivative time constant

61362 © IEC:2012 – 15 –
Sub-
Term Definition Symbol Unit
clause
3.6.12 dead band the maximum band between two values inside of which the i –

x
variation of the controlled variable does not cause any
governing action
SEE: Figure 5
3.6.13 insensitivity one-half of the dead band i /2 –
x
X
X
r
i
x
Y
1,0 Y
max
IEC  387/12
Figure 5 – Dead band
Sub-
Term Definition Symbol Unit
clause
3.6.14 minimum servo- the opening/closing time for one full servo-motor stroke at T , T s

g f
maximum velocity, cushioning times disregarded
motor opening/
closing time
SEE: Figure 6
Note 1 to entry Minimum servomotor opening and closing
times are the result of hydraulic transient calculations.

– 16 – 61362 © IEC:2012
Y
Y
max
1,0
0 t
T
f
T
g
IEC  388/12
NOTE In case of stepped opening/closing velocities a diagram may be provided.
Figure 6 – Minimum servomotor opening/closing time

Sub-
Term Definition Symbol Unit
clause
3.6.15 time constant the reciprocal value of the slope of the curve showing the T s
y
servomotor velocity dy/dt as a function of the relative deviation
of the servo-
of the position of the control valve, s, s , from the zero
positioner
v
position related to s, s = 1 (s, s = 1 theoretical relative spool
v v
stroke in the absence of feedback)
SEE: Figure 7
dy
dt
T
y2
T
g T
y1
1,0
s,s
v
T
f
IEC  389/12
Figure 7 – Time constant of the servo-positioner

61362 © IEC:2012 – 17 –
Sub-
Term Definition Symbol Unit
clause
3.6.16 servo- the maximum possible change in the servomotor position i –
a
which can occur for a given constant value of the input
positioner
signal of the servo-positioner
inaccuracy
SEE: Figure 8
Y
Y
max
1,0
i
a
1,0
s,s
v
IEC  390/12
Figure 8 – Servo-positioner inaccuracy

Sub-
Term Definition Symbol Unit
clause
3.6.17 control system time interval between a specified change in speed or T s
q
dead time command signal and the first detectable movement of the
servomotor
SEE: Figure 9
y
≥ 10 %
T
q
t
IEC  391/12
Figure 9 – Control system dead time

– 18 – 61362 © IEC:2012
Sub-
Term Definition Symbol Unit
clause
3.6.18 actuating energy required energy for one servomotor stroke under the E N · m
R
minimum required pressure p = E /V
R R S
3.6.19 servomotor oil volume of the servomotors V m
S
volume
3.6.20 tripping oil volume oil volume of the pressure tank at the tripping point V m
T
(between p and p , see Figure 20)
T R
3.6.21 usable oil volume usable oil volume between p and p V m
o min R u
(Figure 20)
3.6.22 residual (not oil volume of the pressure tank after a full-load shut-down V m
res
usable) oil volume from the tripping point
(Figure 20)
a
3.6.23 design oil design pressure of the oil pressure tank p Pa
D
pressure
a
3.6.24 operating oil operating oil pressure under normal operating condition p Pa
o
pressure
a
3.6.25 tripping oil when the tripping pressure p is reached a shutdown is p Pa
T T
pressure released, this implies p < p < p < p
R T o D
a
3.6.26 minimum required minimum required pressure in the oil servo system p Pa
R
pressure
a
The unit bar is also used.
4 Control structure
4.1 General
In the hydraulic turbine control, various tasks can be specified with varying priority. Realization
leads to certain typical control system structures and in turn to some basic rules to be adhered
to.
Such typical arrangements are compiled for clarification.
4.2 Main control functions
4.2.1 General
In hydraulic turbine control, these major control functions can be distinguished:
– speed control;
– power output control;
– water level control;
– opening, and
– flow control.
In some systems, combinations of these control functions also occur.

61362 © IEC:2012 – 19 –
4.2.2 Speed control
The purpose of the speed control basically is to maintain constant frequency. In the various
modes of operation this means that:
– in the isolated network mode with only one unit (small network), the actual speed and
therefore the frequency corresponds to the command signal setting; in the isolated network
mode with more than one unit (medium network), the speed control contributes to the
frequency control through the permanent droop avoiding oscillation between the units;
– in the operation on the grid, where the speed is determined by the network frequency, the
speed control contributes to the network frequency control through the permanent droop
and the dynamic characteristics of the controlled system;
– in the no load mode (before synchronization and after separation from the network), the
actual speed corresponds to the command signal or the existing network frequency with
some small deviation.
4.2.3 Power output control
The power output control with a separate power controller is applied with the unit connected to
the grid, its purpose is to control the power output of the unit according to a power command
signal irrespective of head variations. Any frequency variation
...