SIST EN 60953-1:2000

Rules for steam turbine thermal acceptance tests -- Part 1: Method A - High accuracy for large condensing steam turbines

Specifies very accurate testing of steam turbines to obtain the level of performance with minimum measuring uncertainty. Defines uniform rules for preparing and carrying out an evaluation of the acceptance tests. Defines also the conditions under which the acceptance tests shall take place. The cost for conducting this test method will generally be justified economically for large and/or proptotype units.

Regeln für thermische Abnahmeprüfungen für Dampfturbinen -- Teil 1: Methode A - Hohe Präzision für große kondensierende Dampfturbinen

Règles pour les essais thermiques de réception des turbines à vapeur -- Partie 1: Méthode A - Haute précision pour les turbines à vapeur à condensation de grande puissance

Spécifie des essais très précis de turbines à vapeur en vue d'obtenir les valeurs des performances avec le minimum d'incertitude de mesure. Définit les règles de base pour la préparation, l'exécution, le dépouillement et l'interprétation des essais. Définit également les conditions dans lesquelles doivent être effectués les essais. Compte tenu du coût des tests, cette méthode est principalement destinée aux tranches de grandes puissance et/ou à des tranches prototypes Cette publication remplace la CEI 46 (1962).

Rules for steam turbine thermal acceptance tests - Part 1: Method A - High accuracy for large condensing steam turbines

General Information

• Status: Published
• Publication Date: 31-May-2000
• ICS: 27.040 - Gas and steam turbines. Steam engines
• Technical Committee: EPT - Steam turbines
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jun-2000
• Due Date: 01-Jun-2000
• Completion Date: 01-Jun-2000
• Ref Project: EN 60953-1:1995 - Rules for steam turbine thermal acceptance tests - Part 1: Method A - High accuracy for large condensing steam turbines

Relations

• Revised: oSIST prEN IEC 60953-1:2025 - Rules for steam turbine thermal acceptance tests - Part 1: High accuracy for large condensing steam turbines
• Effective Date: 11-Feb-2025

Overview

EN 60953-1:1995 - Rules for steam turbine thermal acceptance tests (Part 1: Method A) defines a high-accuracy procedure for conducting and evaluating thermal acceptance tests on large condensing steam turbines (typically driving generators). Adopted by CLC from the IEC text, this standard specifies stringent test conditions, instrumentation and evaluation rules intended to produce test results with minimum measuring uncertainty. Method A is aimed at large and/or prototype units where the cost of very accurate testing is economically justified.

Key topics and technical requirements

• Objective and scope
  • High-accuracy thermal acceptance tests for condensing steam turbines; also relevant to some non-generator applications.
  • Tests are designed to determine performance levels for comparison with contractual guarantees.
• Measuring uncertainty targets
  • Very low uncertainty: typically about 0.3% for fossil-fired units and 0.4% for nuclear units when Method A provisions are applied.
• Instrumentation and calibration
  • Exclusive use of highly accurate, calibrated instruments and best-practice measuring procedures.
  • Calibration before and after tests; continuous leads for thermocouples; strict instrument tolerances.
  • Electrical power instruments must be checked by comparison after each run with permissible differences (example limit: 0.15%).
• Flow, pressure and temperature measurement
  • Primary mass flow measurement using calibrated differential-pressure devices; throat-tap nozzle is recommended and detailed for calibration with upstream/downstream piping and flow straighteners.
  • Detailed requirements for pressure tapping, manifolds, connecting lines and exhaust pressure measurement for condensing turbines.
  • Temperature measurements require double measurement of main temperatures with maximum differences (example: 0.5 K) and specified thermometer wells.
• Steam quality and special methods
  • Accepted steam quality techniques include tracer, condensing and constant-rate injection methods; guidance on tracer use and enthalpy determination is provided.
• Test planning and execution
  • Stringent rules for test timing, duration, constancy of conditions, preliminary tests, leakage checks and recording.
  • Evaluation includes correction to guarantee conditions and comparison procedures without normally needing to account for measuring uncertainty.

Applications and users

• Who uses it: turbine manufacturers, power plant owners/operators, test laboratories, commissioning engineers, and acceptance-test consultants.
• Typical applications: acceptance testing of large utility steam turbines, prototype validation, contractual performance verification and generator-coupled turbine commissioning.
• Economic rationale: applied where high accuracy is needed to settle contractual guarantees or for units whose performance value justifies the test cost.

Related standards

• References in the document include IEC Publication 34-2 (rotating electrical machines testing) and ISO 5167 (flow measurement by orifice, nozzle and Venturi). Users should review these for complementary measurement methods and calculations.

Keywords: EN 60953-1:1995, steam turbine thermal acceptance tests, Method A, high accuracy, large condensing steam turbines, measuring uncertainty, flow measurement, calibration, steam quality, acceptance testing.

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2000
Rules for steam turbine thermal acceptance tests - Part 1: Method A - High
accuracy for large condensing steam turbines
Rules for steam turbine thermal acceptance tests -- Part 1: Method A - High accuracy for
large condensing steam turbines
Regeln für thermische Abnahmeprüfungen für Dampfturbinen -- Teil 1: Methode A -
Hohe Präzision für große kondensierende Dampfturbinen
Règles pour les essais thermiques de réception des turbines à vapeur -- Partie 1:
Méthode A - Haute précision pour les turbines à vapeur à condensation de grande
puissance
Ta slovenski standard je istoveten z: EN 60953-1:1995
ICS:
27.040 Plinske in parne turbine. Gas and steam turbines.
Parni stroji Steam engines
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEI
NORME
IEC
INTERNATIONALE
953-1
INTERNATIONAL
Première édition
First edition
STANDARD 1990-12
Règles pour les essais thermiques de
réception des turbines à vapeur
Première partie:
Méthode A — Haute précision, pour turbines à
vapeur à condensation de grande puissance
Rules for steam turbine thermal acceptance
tests
Part 1:
Method A — High accuracy for large condensing
steam turbines
© CEI 1990 Droits de reproduction réservés — Copyright — all rights reserved
publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
Aucune partie de cette
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utilisée sous quelque forme que ce soit et par
photocopying and microfilm, without permission in writing
électronique ou mécanique. y compris la photocopie et les
from the publisher.
microfilms, sans l'accord écrit de [éditeur
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Bureau Central de la Commission Electrotechnique Internationale 3, rue de Varembé
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PRICE CODE
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Pourpnx voir catalogue en vigueur
• •
For puce see current catalogue

953-1 © IEC - 3 -
CONTENTS
Page
FOREWORD 9
PREFACE
I 1
INTRODUCTION
Clause
1. Scope and object
1.1 Scope
1.2 Object
1.3 Matters to be considered in the contract
2. Units, symbols, terms and definitions
2.1 General
2.2 Symbols, units
2.3 Subscripts, superscripts and definitions 21
2.4 Definition of guarantee values and test results
2.4.1 Thermal efficiency 27
2.4.2 Heat rate 29
2.4.3 Thermodynamic efficiency 29
2.4.4 Steam rate 29
2.4.5 Main steam flow capacity 3 I
2.4.6 Maximum power output 31
3. Guiding principles
3.1 Advance planning for test 31
3.2 Preparatory agreements and arrangements for tests
3.3 Planning of the tests 35
3.3.1 Time for acceptance tests
3.3.2 Direction of acceptance tests
3.3.3 Cost of acceptance tests
3.4 Preparation of the tests
3.4.1 Condition of the plant
3.4.2 Condition of the steam turbine 37
3.4.3 Condition of the condenser 37
3.4.4 Isolation of the cycle 37
3.4.5 Checks for leakage of condenser and feedwater heaters
3.4.6 Cleanliness of the steam strainers
3.4.7 Checking of the test measuring equipment
3.5 Comparison measurements 43
3.6 Settings for tests
3.6.1 Load settings
3.6.2 Special settings
3.7 Preliminary tests 45
3.8 Acceptance tests
3.8.1 Constancy of test conditions
3.8.2 Maximum deviation and fluctuation in test conditions
47 3.8.3 Duration of test runs and frequency of readings
49 3.8.4 Reading of integrating measuring instruments
3.8.5 Alternative methods
3.8.6 Recording of tests
3.8.7 Additional measurements
3.8.8 Preliminary calculations
3.8.9 Consistency of tests
3.9 Repetition of acceptance tests
51 4. Measuring techniques and measuring instruments
4.1 General
4.1.1 Measuring instruments
4.1.2 Measuring uncertainty
4.1.3 Calibration of instruments
4.1.4 Alternative instrumentation
4.1.5 Mercury in instrumentation
4.2 Measurement of power
63 4.2.1 Determination of mechanical turbine output
4.2.2 Measurement of boiler feed pump power
69 4.2.3 Determination of electrical power of a turbine generator

— 5 —
953-1 © IEC
Clause Page
4.2.4 Measurement of electrical power 69
4.2.5 Electrical instrument connections
4.2.6 71
Electrical instruments
4.2.7 Instrument transformers
4.2.8 Comparison measurement and recalibration of instruments and transformers
4.3 Flow measurements
4.3.1 Determination of flows to be measured
4.3.2 73
Measurement of primary water flow
4.3.3 Installation and location of differential pressure devices
4.3.4 Differential pressure measurements 79
4.3.5
Water flow fluctuation 83
4.3.6 Secondary flow measurements 83
4.3.7 Occasional secondary flows
4.3.8 Density of water and steam
91 4.3.9 Determination of cooling water flow of condenser
4.4 Pressure measurements (excluding condensing turbine exhaust pressure)
4.4.1 Pressures to be measured
4.4.2 Instruments
4.4.3 Pressure tapping holes and connecting lines
4.4.4 Shut-off valves 97
4.4.5 Calibration of pressure measuring devices 97
4.4.6 Atmospheric pressure 97
4.4.7 Correction of readings
101 4.5 Condensing turbine exhaust pressure measurement
4.5.1 General
4.5.2 Plane of measurement
4.5.3
Pressure taps
4.5.4 Manifolds
4.5.5 Connecting lines
4.5.6 Instruments
4.5.7 Tightness of measuring system
4.5.8
Calibration
4.5.9 Correction of readings
4.6 Temperature measurement
4.6.1 Points of temperature measurement
4.6.2 Instruments
109 4.6.3 Main temperature measurements
4.6.4 Feed train temperature measurements (including bled steam)
I11
Condenser cooling water temperature measurement 4.6.5
4.6.6 Accuracy of temperature measuring equipment
I11
4.6.7 Thermometer wells
Precautions to be observed in the measurement of temperature 4.6.8
4.7 Steam quality measurement
4.7.1 General
4.7.2 Tracer technique
4.7.3 Condensing method
4.7.4
Constant rate injection method
4.7.5 Extraction enthalpy determined by constant rate injection method
4.7.6 Tracer and their use
4.8 Time measurement
4.9 Speed measurement
5. Evaluation of tests
5.1 Preparation of evaluation
5.2 Computation of results
5.2.1 Calculation of average values of instrument readings
5.2.2 Correction and conversion of averaged readings
5.2.3 Checking of measured data
5.2.4 Thermodynamic properties of steam and water
5.2.5 Calculation of test results
6. Correction of test results and comparison with guarantee
133 6.1 Guarantee values and guarantee conditions
6.2 Correction of initial steam flow capacity
6.3 Correction of maximum output
Correction of thermal and thermodynamic efficiency 135
6.4
6.5 Definition and application of correction values
6.6 Correction methods
6.6.1 Correction by heat balance calculation 139

7 —
953-1 © 1 EC —
Page
Clause
6.6.2 Correction by use of correction curves prepared by the manufacturer 141
6.6.3 Tests to determine correction values
6.7 Variables to be considered in the correction
6.7.1 Turbines with regenerative feed-water heating
6.8 Guarantee comparison
6.8.1 Guarantee comparison with locus curve
6.8.2 Guarantee comparison with guarantee point
6.8.3 Guarantee comparison for turbines with throttle regulation
APPENDIX A — Feedwater heater leakage and condenser leakage tests
APPENDIX
B — Throat tap nozzle
161 APPENDIX C — The use of flow straighteners in fluid flow measurements

953-1 © IEC — 9 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
RULES FOR STEAM TURBINE THERMAL ACCEPTANCE TESTS
Part 1: Method A — High accuracy for large condensing steam turbines
FOREWORD
The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on which all the
1)
National Committees having a special interest therein are represented, express, as nearly as possible, an international
consensus of opinion on the subjects dealt with.
They have the form of recommendations for international use and they are accepted by the National Committees in that
2)
sense.
In order to promote international unification, the IEC expresses the wish that all National Committees should adopt the
3)
text of the IEC recommendation for their national rules in so far as national conditions will permit. Any divergence
between the IEC recommendation and the corresponding national rules should, as far as possible, be clearly indicated in
the latter.
PREFACE
This standard has been prepared by IEC Technical Committee No. 5: Steam turbines.
The text of this standard is based on the following documents:
Report on Voting
Six Months' Rule
5(CO)27
5(CO)23
Full information on the voting for the approval of this standard can be found in the Voting
Report indicated in the above table.
The following IEC publication is quoted in this standard:
Publication No.34-2(1972): Rotating electrical machines. Part 2: Methods for determining losses and efficiency of
rotating electrical machinery from tests (excluding machines for traction vehicles).
Other Publication quoted:
flow by means of orifice plates, nozzles and Venturi tubes inserted in
ISO Standard 5167(1980): Measurement of fluid
circular cross-section conduits running full.

I 1 —
—
953-1 © IEC
RULES FOR STEAM TURBINE THERMAL ACCEPTANCE TESTS
Part 1: Method A — High accuracy for large condensing steam turbines
INTRODUCTION
The rapid development of measuring techniques, the increasing capacity of steam turbines and
the introduction of nuclear power plants necessitated a revision of IEC Publication 46 (1962)
regarding acceptance tests.
Since all the needs of the power industry in the different parts of the world could not be satisfied
by one single publication, the complete standard is divided into two parts, describing two different
approaches for conducting and evaluating thermal acceptance tests of steam turbines and which
can be used separately:
a)
Method A, which is Part 1 of the standard (IEC 953-1), deals with thermal acceptance tests with
high accuracy for large condensing steam turbines.
b) Method B, which is Part 2 of the standard (IEC 953-2), deals with thermal acceptance tests with a
wide range of accuracy for various types and sizes of steam turbines.
1) Basic philosophy and figures on uncertainty
Pa
rt 1 provides for very accurate testing of steam turbines to obtain the level of performance with
minimum measuring uncertainty. The operating conditions during the test are stringent and
compulsory.
Method A is based on the exclusive use of the most accurate calibrated instrumentation and the
best measuring procedures currently available. The uncertainty of the test result is always suf-
ficiently small that it normally need not be taken into acount in the comparison between test result
and guarantee value. This uncertainty will not be larger than about 0.3% for a fossil fired unit and
0.4% for a nuclear unit.
The cost for instrumentation and the efforts for preparing and conducting the tests will generally
be justified economically for large and/or prototype units.
Method B provides for acceptance tests of steam turbines of various types and capacities with
appropriate measuring uncertainty. Instrumentation and measuring procedures have to be chosen
accordingly from a scope specified in the standard which is centred mainly on standardized
instrumentation and procedures, but may extend eventually up to very high accuracy provisions
requiring calibration. The resulting measuring uncertainty of the test result is then determined by
calculating methods presented in the standard and normally, if not stated otherwise in the contract,
taken into account in the comparison between test result and guarantee value. The total cost of an
acceptance test can therefore be maintained in relationship with the economic value of the
guarantee values to be ascertained.
The specifications of the operating conditions during the test are somewhat more flexible in this
method; furthermore, procedures are recommended for treating cases where these specifications
cannot be met.
IEC
953-1 © — 13 —
When good-standardized instrumentation and procedures are applied in a test, the measuring
uncertainty of the result will usually amount to 0.9% to 1.2% for a large fossil fuel fired condensing
unit, to 1.1 % to 1.4% for a nuclear unit and to 1.5% to 2.5 % for back pressure, extraction and small
condensing turbines. It is possible to reduce these values by additional improvement in instrumen-
tation, primarily by additional measurements of primary mass flows and/or calibration of
ow.
measuring devices for primary mass fl
2) B
Main difference between Methods A and
In Method A, much more detailed information concerning the preparation and conduct of the
tests and the measuring techniques are contained for guidance of the parties to the test than in
Method B. In Method B, the detailed treatment of these objectives is left somewhat more to the
discretion and decisions of the participants and necessitates sufficient experience and expertise on
their part.
3) Guiding principles
The requirements concerning the preparation and conditions of the test and especially such
conditions of the test as duration, deviations and constancy of test conditions and acceptable
differences between double measurements are more stringent in Method A.
The test should be conducted preferably within eight weeks after the beginning of the operation.
It is the intent during this period to minimize performance deterioration and risk of damage to the
turbine.
Preliminary tests including enthalpy drop tests should be made during this period to monitor HP
and IP turbine section performance. However, these tests do not provide LP section performance
and for this reason it is imperative to conduct the acceptance tests as soon as practicable.
Whatever the case, when using Method A, if an enthalpy drop test indicates a possible
deterioration of the HP or IP section, or if the plant conditions require that the tests be postponed
more than four months after the initial start, then the acceptance tests should be delayed.
An adjustment of the heat rate test results to start-up enthalpy drop efficiencies or for the effects
of aging is not permitted when using Method A.
If the test has to be postponed, Method A proposes that the test be carried out after the first major
internal inspection; several methods are proposed for establishing the approximate condition of the
turbine prior to the tests.
4) Instruments and methods of measurement
Measurement of electrical power
a)
In addition to the conditions required for the measurement of electric power, which are similar
in both methods, Method A requires a check of the instruments by a comparison measurement
after each test run; the permissible difference between double measurements is limited to 0.15%.
b) Flow measurement
For the measurement of main flows the use of calibrated pressure difference devices is required
in Method A. The application of a device not covered by international standardization, the
throat-tap nozzle, is recommended therein and details of design and application are given.
The calibration of these devices shall be conducted with the upstream and downstream piping
and flow-straightener. Methods for the necessary extrapolation of the discharge coefficient from
the calibration values are given.
flow
In Method B standardized pressure-difference devices are normally applied for
measurement. Calibration is recommended where a reduction of overall measuring uncertainty

— 15 — 953-1 © I EC
fl ow is recommended for the reduction
is desirable. Double or multiple measurement of primary
of measuring uncertainty and a method for checking the compatibility is described.
Pressure measurement
c)
The requirements and recommendations for pressure measurements are essentially similar. Only
the methods for the measurement of exhaust-pressure of condensing turbines differ to some
extent.
d) Temperature measurement
The requirements are essentially similar in both methods. However detail requirements are more
stringent in Method A:
calibration before and after the test,
—
— double measurement of the main temperature with 0.5 K maximum difference,
— thermocouples with continuous leads,
— required overall accuracy.
e) Steam quality measurements
Methods A and B are identical.
5) Evaluation of tests
The preparatory work for the evaluation and calculation of the test results is covered in a very
similar manner in Methods A and B. However, quantitative requirements are more stringent in
Method A.
Method B contains some proposals for handling cases where some requirements have not been
met to avoid rejection of the test.
In addition, Method B contains detailed methods for calculation of measuring uncertainty values
of measured variables and test results.
Method B recommends other methods for conducting and evaluating of the tests after the
specified period and without a previous inspection.
6) Correction of test results and comparison with guarantees
The correction of test results to guarantee conditions is covered in both Methods A and B.
Method A provides for the comparison of test results to guarantee without consideration of
measuring uncertainty.
Method B gives a broader spectrum of correction procedures. Furthermore, the measuring
uncertainty of the result is taken into account in the guarantee comparison.
7) Proposals for application
Since the acceptance test method to be applied has to be considered in the details of the plant
design, it should be stated as early as possible, preferably in the turbine contract, which method will
be used.
Method B can be applied to steam turbines of any type and any power. The desired measuring
uncertainty should be decided upon sufficiently early, so that the necessary provisions can be
included in the plant.
If the guarantee includes the complete power plant or large parts thereof, the relevant parts of
either method can be applied for an acceptance test in accordance with the definition of the
guarantee value.
— 17 —
953-1 © IEC
Scope and object
1.
1.1 Scope
The rules given in this standard are applicable primarily to thermal acceptance tests with
high accuracy for condensing steam turbines driving generators for electric power services.
Some of the provisions of these rules are relevant to turbines for applications other than
driving electric power generators.
These rules provide for the testing of turbines operating with either superheated or satu-
rated steam. They include measurements and procedures required to determine specific
enthalpy within the moisture region and describe precautions necessary to permit testing
while respecting radiological safety rules in nuclear plants.
These rules contain information also applicable to the testing of back-pressure turbines,
extraction turbines and mixed-pressure turbines. Only the relevant portion of the rules need
apply to any individual case.
Uniform rules for the preparation, carrying out and evaluation of the acceptance tests are
defined in this standard. Details of the conditions under which the acceptance tests shall take
place are included.
Should any complex or special case arise not covered by these rules, appropriate agreement
shall be reached by manufacturer and purchaser before the contract is signed.
1.2 Object
The purpose of the thermal acceptance tests of steam turbines and turbine plants described
in this standard is to verify any guarantees given by the manufacturer of the plant concerning:
a) turbine plant thermal efficiency or heat rate;
flow
turbine thermodynamic efficiency or steam rate or power output at specified steam
b)
conditions;
c) main steam flow capacity and/or maximum power output.
The guarantees with their provisions shall be formulated completely and without contradic-
tions (see 2.4). The acceptance tests may also include such measurements as are necessary for
corrections according to the conditions of the guarantee and checking of the results.
1.3 Matters to be considered in the contract
Some matters in these rules have to be considered at an early stage. Such matters are dealt
with in the following sub-clauses:
Sub-clause
(paragraph 4)
1.1
1.2 (paragraph 2)
(paragraphs 3 and 4)
3.1
(paragraph 1)
3.3.3
6.6
6.8
IEC — 19 —
953-1 ©
2. Units, symbols, terms and definitions
2.1 General
The International System of Units (SI) is used in these rules; all conversion factors can
therefore be avoided.
The coherent units for all relevant quantities are given in the Table in 2.2. Some conversion
factors are given as well for specific heat rates based on units other than W/W.
2.2 Symbols, units
For the purpose of these rules the following symbols, definitions and units shall be used:
Exemples de
Autres unités
Symboles Unités multiples et
Grandeurs
ISO
sous-multiples
P W kW
Puissance
kg/s
Débit masse m
bar1>
Pa kPa
Pression absolue Jabs
bar)>
Pa kPa
Pression manométrique
Pe
Pa kPa bar)) mbar
Pression ambiante (barométrique)
Pamb
Ap Pa kPa .
Différence de pression
K
Température thermodynamique T, O
t, S °C
Température Celsius
At K
Ecart de température
H m mm
Distance verticale
h J/kg kJ/kg
Enthalpie massique
J/kg kJ/kg
Chute d'enthalpie massique Ah
c J/kg • K kJ/kg • K
Chaleur massique
Titre (masse de vapeur saturée sèche
x kg/kg g/g
par unité de masse de vapeur humide)
min-'
n s-I
Vitesse de rotation
m/s
Vitesse linéaire y
e kg/m3
Masse volumique
y m3/kg
Volume massique
D m mm
Diamètre
g m/s2
Accélération de la pesanteur
W/W kW/kW
Rendement thermique
rit
W/W kW/kW
Rendement thermodynamique rltd
kW/kW kJ/kW • s,
HR W/W
Consommation spécifique de chaleur
kJ/kWh
kg/kW • h
SR kg/W • s kg/kW • s
Consommation spécifique de vapeur
ou
kg/J kg/kJ
Q J/s kJ/s
Débit de chaleur
Facteur de cavitation K
C Selon nature
Concentration
du traceur
F 1
Facteur de correction selon 6.6a)
I
Facteur de correction selon 6.6b) F*
—
Exposant isentropique K
Coefficient de décharge Cd —
Coefficient de débit a —
Admitted by CIPM and ISO for temporary use with fluids only.
1 )
953-1 © IEC — 21 —
Relation between Heat Rate and Thermal Efficiency:
Units used for HR Relationship
W/W, kW/kW, kJ/kW  s
HR = 1
tic
3 600
kJ/kW  h HR —
tit
1 000
kJ/MW s HR —
ti t
859.845
— kcal/kW  h HR
tit
3412.14
— BTU/kW  h HR
tit
Subscripts, superscripts and definitions
2.3
Quantity Subscript Position or definition
Power b At generator terminals
a Taken by auxiliaries not driven by the turbine (see 4.2.3);
(see also IEC 34)
Net power output: P5 = Pc, — P;,
g
c At turbine coupling, less power required by turbine
auxiliaries, if driven separately (see 4.2.3)
Internal to the turbine
mech Mechanical losses of pump and pump drive
Initial steam flow rate and output max Values for fully opened control valves
Steam condition and flow rate 1 Directly upstream of high pressure (HP) turbine stop
valve(s) and the steam strainer(s) (if any) that are
included in the turbine contract
2 At exhaust of the turbine HP from which steam passes to the
reheater
Directly upstream of intermediate pressure (IP) turbine stop
valves
4 At exhaust of the turbine(s) discharging to the condenser
Condensate and feed water 5 At condenser discharge
conditions and flow rates
6 At inlet to condensate pump
7 At discharge from condensate pump
8 See figure la
At inlet of boiler feed pump
10 At outlet of boiler feed pump
lI At outlet of final feed heater
b After passage through the condensate pump and any coolers
(oil, generator, gas/air) included in the contract
d At outlet from the drain cooler
a At outlet of air ejector condenser
Refers to water taken from the feed-water system to the
is
superheater for regulation of the initial steam temperature
ir Refers to water taken from the feed-water system to the
reheater for control of the reheated steam temperature

953-1 © IEC - 23 -
Position or definition
Quantity Subscript
Make up water conditions and m Measurements adjacent to the inlet flange of the condensate
flow rate system or of the evaporator
Gland steam conditions and flow g Steam supplied to glands from a separate source
rates
gl Leak-off steam from glands and valve stems returned to the
system and included in the initial steam flow
q Flow of leak-off steam from glands and valve stems at inlet
end or before a reheater which is led away for any
extraneous purpose and neither it nor its heat is delivered
to any part of the turbine cycle
qy Leak-off flows similar to q, but coming from a point or
points downstream of a reheater
Main steam flow rate and concen- M Main steam flow at outlet of reactor
tration
Mass flow rate and concentration F Refers to feed-water for reactor
core Refers to medium fluid passing through reactor core
cond Refers to condensed steam
Refers to injected tracer solution
inj
Mass flow rate and concentration
At entry into core of PWR
E
Recirculated water flow from water separator
R
w
Condenser cooling water
wi Condenser inlet
wo Condenser outlet
Average value between condenser inlet and outlet
wio
Thermal
Efficiency t
Thermodynamic
td
s Refers to isentropic enthalpy drop
Enthalpy drop
At throat of flow-metering nozzle
throat
Velocity
Saturation pressure of water at pertinent temperature
sat
Static pressure
wat In water phase
Concentration
L In pump loop of BWR
In blow-down water of PWR
B
Of injected tracer
inj
At injection point before tracer injection
O
g Guaranteed
Test results and guaranteed values
Corrected
c
Measured
m
Product of all individual correction factors
tot
Correction factor F or F*
Numbering of individual correction factors
I, 2, 3
For correction of efficiency
ri
For correction of output
P
i, j Numbering subscripts
General use
Definition
Superscript
Quantity
Reference value of computer-calculated efficiency
/
Efficiency
— Average value
General
953-1 © IEC — 25 —
m
3
•
mgl
483/90
GC: Generator gas cooler
OC: Oil cooler
DC: Drain cooler
EC: Air ejector condenser
The point number remains the same for the same item of any other turbine type: for example, Point 9 will be at the inlet of
the feed pump, Point 8 may be anywhere between Points 6 and 11.
FIG. la. — Reheating regenerative condensing turbine with feed-water heating.
l
FtG. b. — Straight condensing or hack-pressure turbins without feed-heating.
FIG. 1. — Diagram for interpretation of symbols and subscripts.

953-1 © I EC — 27 —
2.4
Definition of guarantee values and lest results
For the quantitative description of the thermodynamic performance of a steam turbine or
steam turbine plant, several quantities are technically appropriate and generally applied.
Guaranteed values are expressed as such quantities and, consequently, test results are to be
evaluated in the same manner.
The general definition of these quantities is always quite obvious. The details, however,
may be different in each case and shall be fully considered (see also 1.2).
2.4.1
Thermal efficiency
For a power station turbine with regenerative feed heating, the thermal efficiency is the
significant criterion. It is defined as the ratio of power output to heat added to the cycle from
external sources.
P
(1)
t— ^ (mi 0 hi)
where:
M . , are the mass flows, to which heat is added
Oh, the resulting enthalpy rises
For each specific case a guarantee heat cycle together with the guarantee terminal par-
ameters has to be defined as a basis for guarantee definition and test evaluation. It should be
as simple as possible and as near as practicable to the cycle configuration to be realized for the
test (see also 3.4.4).
A practical definition for a turbine plant with single reheat and feed heating according to
figure 1 a is then:
_ Pb (or Pg or P )*
c
(2)
i — h i i ) + m 3 — h2)
m i (h 3 (h
Any additional heat and/or mass flow added to or subtracted from the cycle for example by
make-up flow m m , spray attemperator flow Mir or /his or additional extraction for steam air
preheater has to be accounted for in the evaluation by an appropriate correction of the test
result (see Clause 6). Losses are not included in this definition, but treated according to
5.2.3.4.
To keep the sum of corrections small, it may be reasonable to include in the guarantee
definition, by means of additional terms, important heat and mass flows, present in the cycle
configuration for the test for technical reasons (e.g. spray attemperator, reactor blow down,
etc.).
This, however, also modifies the thermodynamic character of the definition and the
resulting values of the thermal efficiency are not directly comparable with those according to
formula (2). Furthermore, the correction procedure will not be avoided altogether in this way,
because it is improbable that the values of these additional flows during the test coincide
exactly with those in the amended guarantee definition.
It is impracticable to describe in these rules all the possible variations in turbine cycles. In
cases of complicated deviations of test cycle configuration from guarantee definition it is
advisable to use the correction procedure according to 6.6.1.
* According to contract specification.

IEC — 29 —
953-1 ©
2.4.2 Heat rate
The heat rate traditionally has been used (and is still used) for the same objective as thermal
efficiency, which is applied in these rules.
In a coherent unit system (SI):
I
HR=— (3)
^7 t
The unit of the so calculated heat rate is kW/kW = kJ/kW  s
Heat rate values expressed in other units can be converted easily to thermal efficiency
values, taking into account the appropriate conversion factors (see 2.2).
2.4.3 Thermodynamic efficiency
For a turbine receiving all the steam at one initial steam condition and discharging all the
steam at a lower pressure (condensing or back-pressure turbine without regenerating feed-
heating or reheat) the thermodynamic efficiency is the most appropriate measure of perform-
ance. It is defined as the ratio of power output to isentropic power capacity (product of steam
ow and isentropic enthalpy drop between initial steam condition and exhaust
mass fl
pressure).
P
(4)
iJtd
r►t O hs
The numerical value of thermodynamic efficiency does not depend on the initial steam and
exhaust conditions, but is the indication for the efficiency of the expansion only.
The formula defining the thermodynamic efficiency for a straight condensing turbine
without feed-heating according to Figure lb is then:
Pg or Pc) *
Pb (or
(5)
qta —
Ahs
mt  1,a
where:
Ah, i t is the isentropic enthalpy drop between initial steam condition at point 1 and pressure at point 4.
2.4.4 Steam rate
The steam rate traditionally has been used (and is still used) as a performance criterion for
ow rate to power
turbines as described in 2.4.3. It is defined as the ratio of initial steam fl
output and is connected with thermodynamic efficiency as follows in coherent units (SI):
SR— m— I (6)
P hs
77td O
Steam rate values expressed in other units can be converted to thermodynamic efficiency
s value, taking into account the appropriate
values after determination of the relevant Oh
conversion factors (see 2.2).
* According to contract specification.

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953-1 © IEC
Since numerical steam rate values depend also on initial steam and exhaust conditions, they
are not comparable for turbines with different specified conditions. Therefore, thermo-
dynamic efficiency is used in these rules.
2.4.5 Main steam flow capacity
The maximum flow rate of main steam with all regulating valves wide open under specified
steam conditions (usually the steam conditions according to the definition of the other
guarantee values) is a measure of the maximum flow capacity of the turbine.
2.4.6 Maximum power output
The power output of the turbine at the maximum flow rate of main steam can be guaranteed
for a specified guarantee heat-cycle, which may differ to some extent from the guarantee heat
cycle valid for the thermal efficiency.
Guiding principles
3.
Advance planning for test
3.1
The parties to any test under these rules shall reach agreement as to the testing procedure,
the interpretation of guarantees, the number, location, and arrangement of measuring points
and measuring devices, valves and piping arrangements at the time of design of the turbine
plant and of the piping. This especially applies to steam turbines in nuclear power stations
where subsequent modifications are often impracticable and the measuring points are not
always accessible once the plant has started to operate. It is recommended that, for the most
important measurements, special connection facilities such as flanges and thermometer wells
be provided for the measuring equipment so that the acceptance tests can be carried out
without impairing the instruments for normal operation.
The instrumentation has to be selected in such a way that power and heat flows which enter
and leave the "system", as defined in the contract, and the conditions at its boundaries can be
determined.
All necessary preparations and precautions have to be taken to meet the specifications of
these rules regarding measuring accuracy.
The following is a list of typical items upon which agreement should be reached during the
plant design:
Location of, and piping arrangement around flow measuring devices on which test calcu-
a)
lations are to be based.
Number and location of valves required to ensure that no unaccounted for flow enters or
b)
leaves the test cycle, or bypasses any cycle component. In a nuclear plant there may be
some make-up line or emergency valving that cannot be blocked and for which accounting
must be made.
Number and location of temperature wells and pressure connections required to ensure
c)
correct measurements at critical points.
Number and location of duplicate instrument connections required to ensure correct
d)
measurements at critical points.
Handling of leak-off flows to avoid complications in testing or the introduction of errors.
e)
Means of measuring pump shaft leakages.
f)
Method of determining steam quality including sampling technique as required. The
g)
recommended methods are given in 4.7.

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953-1 ©
Specification, installation, precision class and calibration of the normal station instrument
transformers shall be chosen suitably if it is intended to use them for the acceptance test (see
also 4.2.7).
3.2 Preparatory agreements and arrangements for tests
a) Before the test, the parties to the tests shall reach an agreement as to the test programme,
the specific objectives of the tests, the measuring methods and the method of operation
with due regard to a limitation of the necessary corrections, the method for correcting the
test results and for guarantee comparison with due regard to the contract conditions.
Agreement shall be reached as to the variables to be measured, the measuring instruments
b)
and who is to supply them, the location of the indicating instruments and the operating
and recording personnel required.
Agreement shall be reached on the methods of obtaining the comparison measurement
c)
(see 3.5).
d) Agreement shall be reached on such matters as the means of securing constancy of steam
conditions and output.
e) Instruments liable to failure or breakage in service should be duplicated by reserve
instruments, properly calibrated, which can be put into service without delay. A record of
such change of instrument during a test shall be clearly made on the observer's record
sheet.
Instruments shall be located and arranged so that they may be read accurately with
comfort by the observer. The calibration environment should be as close as practicable
to the environment in which the instrument will operate during the test. This may be
accomplished by locating the instruments in a controlled environment.
f) The determination of the enthalpy of steam superheated less than 15 K, or of the quality of
steam containing moisture, may be made only when the parties agree upon the method to
be employed for this determination. The agreement, the method for making the determi-
nation and the method of applying the enthalpy or quality values to the test results shall be
fully described in the test report.
The rate of flow of steam of any quality may be determined, where practicable, by
condensing it completely and then measuring the condensate flow.
Agreement shall be reached as to the method of calibration of instruments, by whom and
g)
when.
For any of the measurements necessary for a test under these rules, any methods may be
h)
employed other than those prescribed in these rules, provided they are mutually agreed
upon in writing before the test by the parties to the test. Any such departure from the
prescribed methods shall be clearly described in the test report. In the absence of written
agreements, the rules herein shall be mandatory.
i) An independent expert may be a party to all agreements.
j) Agreement shall be reached on the minimum number of operating and recording person-
nel that is required.
953-1 © IEC — 35 —
Planning of the tests
3.3
Time for acceptance tests
3.3.1
Unless otherwise provided in the contract, acceptance tests on site should be planned to
take place if practicable within eight weeks* after the first synchronization, or immediately
following an inspection outage, provided any deficiencies affecting performance have been
corrected. In any event, except with written agreement to the contrary, the acceptance test
shall take place within the guarantee period specified in the contract.
3.3.2 Direction of acceptance tests
The responsibility for the direction of the acceptance tests shall be clearly assigned by the
ies prior to the test, preferably to one person. This person is responsible for the correct
part
execution and evaluation of the acceptance tests, and serves as arbitrator in the event of
disputes as to the accuracy of observations, conditions, or methods of operation. He is
entitled and obliged to obtain information on all necessary details.
Accredited representatives of the purchaser and the manufacturer may at all times be
present to verify that the tests are conducted in accordance with these rules and the
agreements made prior to the tests.
A party to the contract who is not responsible for the direction of the acceptance tests shall
also be given the opportunity of obtaining information a sufficient time before the tests.
of acceptance tests
3.3.3 Cost
The contract shall stipulate who is to bear the costs of acceptance tests and any repeated
acceptance tests (see also 3.5, 3.7 and 3.9).
Preparation of the tests
3.4
3.4.1 Condition of the plant
Prior to commencement of the acceptance tests, it is essential to be satisfied that the steam
turbine and driven machine are in suitable condition, together with the condenser and/or
feedheaters if included in the guarantee. It is also essential to verify that leaks in the con-
denser, feedheaters, pipes and valves have been eliminated.
Prior to the acceptance tests, the supplier shall be given the opportunity to check the
condition of the plant, if necessary by making his own measurements. Any deficiency deter-
mined at this time shall be rectified.
Although these rules deal specifically with the performance testing of steam turbine
generators, it is required that all other equipment supplied as part of the same turbine
generator contract shall be in full and correct working order and in normal commercial
disposition during the turbine generator tests. This requirement does not apply if other
equipment has been ordered as an extra to the contract after the performance guarantees have
been contractually agreed, or if special measures to render the equipment non-operative
* It is the intention, during this period, to minimize performance deterioration and risk of damage to the turbine.
Enthalpy drop tests or preliminary tests should be made during this period to monitor HP and IP turbine section
performance. However, these tests do not provide LP section performance and for this reason it is imperative to
conduct the acceptance test as soon as practicable.
In any event, if either the enthalpy drop test shows undue deterioration to the HP or LP section, or if plant
conditions delay the tests for more than four months after initial operation, the acceptance test should be
postponed.
Adjusting of heat rate test results to startup enthalpy drop efficiencies or for the effects of ageing is not permitted.

37 —
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during the tests have been agreed beforehand between the parties to the test and are described
in prominent detail in the test report. An example of equipment in this category would be
piping and valves, supplied as part of the same turbine generator contract, designed to permit
steam to by-pass part or all of the turbine expansion stages for temperature-matching
purposes during start-up.
3.4.2 Condition of the steam turbine
The condition of the steam turbine can be determined by an internal inspection of the steam
path generally by opening the steam turbine or by comparison measurements according
to 3.5.
Opening the turbine or an individual casing in order to locate a defect may be taken into
consideration if large and inexplicable deviations are apparent from the comparison
measurements.
3.4.3 Condition of the condenser
When the guarantees include the condenser performance and are based upon cooling water
flow and temperature, the condenser shall be clean and the system shall be tested for sufficient
air tightness. Agreement of the two parties to these matters shall be reached.
The condition of the condenser shall be checked by opening the water boxes or measuring
the terminal temperature difference. In the case of deposits* the condenser shall be cleaned by
the purchaser prior to the acceptance tests at the request of the supplier, or the parties
concerned by the test may agree on a suitable correction.
3.4.4 Isolation of the cycle
The accuracy of the test results depends on the isolation of the system. Extraneous flows
should be isolated from the system and internal flows which bypass in an unaccounted-for
way either cycle components or mass-flow measuring equipment should be eliminated, if
practicable, to obviate the need for measurement. If there is any doubt about the ability to
isolate these flows during the test, preparations shall be made prior to the test to measure
them.
All unused connections shall be blanked-off. If this is not practicable the connections shall
be broken at a suitable point so that the outlets are under constant observation.
The equipment and flows to be isolated and the methods to accomplish this should be
agreed well ahead of the initial operation date of the turbine. The isolation of
...