IEC 62862-4-1:2022

IEC 62862-4-1
®

Edition 1.0 2022-09
INTERNATIONAL
STANDARD



Solar thermal electric plants –
Part 4-1: General requirements for the design of solar power tower plants

IEC 62862-4-1:2022-09(en)

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IEC 62862-4-1

®


Edition 1.0 2022-09




INTERNATIONAL



STANDARD




















Solar thermal electric plants –

Part 4-1: General requirements for the design of solar power tower plants



























INTERNATIONAL

ELECTROTECHNICAL


COMMISSION





ICS 27.160 ISBN 978-2-8322-5651-0




  Warning! Make sure that you obtained this publication from an authorized distributor.


® Registered trademark of the International Electrotechnical Commission

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– 2 – IEC 62862-4-1:2022  IEC 2022
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 8
4 Basic requirements . 9
5 Electric power system requirements . 10
5.1 General requirements . 10
5.2 Requirements for grid-connection . 10
5.3 Relay protection and automatic safety device . 10
5.4 Dispatching automation . 10
5.5 Electric power system communication . 11
5.6 Electric energy metering . 11
6 Solar resource assessment. 11
7 Site selection . 11
8 Overall planning . 12
8.1 General requirements . 12
8.2 Off-site planning . 12
8.3 On-site planning. 13
9 Layout of heliostat field and receiver tower . 14
9.1 General requirements . 14
9.2 Layout of heliostat field . 14
9.3 Layout of receiver tower . 14
9.4 Safety protection facilities . 15
9.5 Maintenance and inspection facilities . 15
10 Layout of power block . 15
10.1 General requirements . 15
10.2 Layout of thermal energy storage area . 16
10.3 Layout of steam generation system area . 16
10.4 Layout of steam turbine house . 17
10.5 Layout of auxiliary heating area . 17
10.6 Maintenance facilities . 17
11 Collector system . 17
11.1 General requirements . 17
11.2 Heliostats . 17
11.3 Receiver . 18
11.4 Heliostat cleaning . 19
12 Heat transfer, thermal energy storage and steam generation system . 19
12.1 General requirements . 19
12.2 Heat transfer system . 20
12.3 Thermal energy storage system . 20
12.4 Steam generation system . 21
12.5 Auxiliary system . 21
13 Steam turbine system . 22
14 Water treatment system . 22
14.1 Water quality and pretreatment . 22

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IEC 62862-4-1:2022  IEC 2022 – 3 –
14.2 Water pre-desalination . 22
14.3 Demineralized water treatment system . 22
14.4 Heliostat cleaning water treatment . 22
14.5 Wastewater treatment . 23
15 Information system . 23
15.1 Security and protection system . 23
15.2 Video monitoring system for production . 23
15.3 Information system cabling . 23
15.4 Information security . 23
16 Instrumentation and control . 23
16.1 Automation level . 23
16.2 Control mode and control room . 23
16.3 Measurements and instrumentation . 24
16.4 Alarms . 24
16.5 Protection . 24
16.6 Analogue control . 25
16.7 Control system . 25
16.8 Power supply to control system . 26
17 Electrical equipment and system . 26
17.1 Generator and main transformer . 26
17.2 AC auxiliary power system . 26
17.3 DC system and AC uninterruptible power supply . 26
17.4 High-voltage electrical switchgear . 27
17.5 Electric monitoring and control . 27
17.6 Elements relay protection. 27
17.7 Lighting system . 27
17.8 Grounding system . 27
17.9 Other facilities . 27
18 Occupational safety and occupational health . 27
Annex A (informative) Electricity output estimation . 28
Bibliography . 30

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

SOLAR THERMAL ELECTRIC PLANTS –

Part 4-1: General requirements for the design of solar power tower plants

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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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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.
IEC 62862-4-1 has been prepared by IEC technical committee 117: Solar thermal electric plants.
It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
117/166/FDIS 117/169/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.

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IEC 62862-4-1:2022  IEC 2022 – 5 –
A list of all parts in the IEC 62862 series, published under the general title Solar thermal electric
plants, can be found on the IEC website.
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,
• replaced by a revised edition, or
• amended.

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– 6 – IEC 62862-4-1:2022  IEC 2022
SOLAR THERMAL ELECTRIC PLANTS –

Part 4-1: General requirements for the design of solar power tower plants



1 Scope
This part of IEC 62862 specifies the general requirements for the design of solar power tower
plants and covers the electric power system requirements, the solar resource assessment, the
site selection, the overall planning, the layout of the heliostat field and the receiver tower, the
layout of the power block, the collector system, the heat transfer, the thermal energy storage
and steam generation system, the steam turbine system, the water treatment system, the
information system, instrumentation and control, the electrical equipment and system,
occupational safety and occupational health.
This document is applicable to the design requirements of newly built, expanded or rebuilt solar
power tower plants employing steam turbines with molten salt or water-steam as heat transfer
fluid. If other heat transfer fluids are employed, it is possible that the provisions set out in this
document will need to be adapted.
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 60034-1, Rotating electrical machines – Part 1: Rating and performance
IEC 60034-3, Rotating electrical machines – Part 3: Specific requirements for synchronous
generators driven by steam turbines or combustion gas turbines and for synchronous
compensators
IEC 60034-16 (all parts), Rotating electrical machines – Part 16: Excitation systems for
synchronous machines
IEC 60038, IEC standard voltages
IEC 60045-1, Steam turbines – Part 1: Specifications
IEC 60076-1, Power transformers – Part 1: General
IEC 60076-2, Power transformers – Part 2: Temperature rise for liquid-immersed transformers
IEC 60076-3, Power transformers – Part 3: Insulation levels, dielectric tests and external
clearances in air
IEC 60076-4, Power transformers – Part 4: Guide to the lightning impulse and switching impulse
testing – Power transformers and reactors
IEC 60076-5, Power transformers – Part 5: Ability to withstand short circuit

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IEC 62862-4-1:2022  IEC 2022 – 7 –
IEC 60076-7, Power transformers – Part 7: Loading guide for mineral-oil-immersed power
transformers
IEC 60086-1, Primary batteries – Part 1: General
IEC 60183, Guidance for the selection of high-voltage A.C. cable systems
IEC 60255 (all parts), Measuring relays and protection equipment
IEC 60479 (all parts), Effects of current on human beings and livestock
IEC TS 60815 (all parts), Selection and dimensioning of high-voltage insulators intended for
use in polluted conditions – Part 1: Definitions, information and general principles
IEC 60839-11-2, Alarm and electronic security systems – Part 11-2: Electronic access control
systems – Application guidelines
IEC 60870-5 (all parts), Telecontrol equipment and systems – Part 5: Transmission protocols
IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic safety-
related systems
IEC 61511 (all parts), Functional safety – Safety instrumented systems for the process industry
sector
IEC 61850 (all parts), Communication networks and systems for power utility automation
IEC 62040-1, Uninterruptible power systems (UPS) – Part 1: Safety requirements
IEC 62052-11, Electricity metering equipment – General requirements, tests and test conditions
– Part 11: Metering equipment
IEC 62053 (all parts), Electricity metering equipment – Particular requirements
IEC 62053-21, Electricity metering equipment – Particular requirements – Part 21: Static meters
for AC active energy (classes 0,5, 1 and 2)
IEC 62053-41, Electricity metering equipment – Particular requirements – Part 41: Static meters
for DC energy (classes 0,5 and 1)
IEC 62271 (all parts), High-voltage switchgear and controlgear
IEC 62305-1, Protection against lightning – Part 1: General principles
IEC 62642-1, Alarm systems – Intrusion and hold-up systems – Part 1: System requirements
IEC 62676-1-1, Video surveillance systems for use in security applications – Part 1-1: System
requirements – General
IEC TS 62749, Assessment of power quality – Characteristics of electricity supplied by public
networks
IEC TS 62862-1-1, Solar thermal electric plants – Part 1-1: Terminology

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IEC TS 62862-2-1, Solar thermal electric plants – Part 2-1: Thermal energy storage systems –
Characterization of active, sensible systems for direct and indirect configurations
IEC 81346 (all parts), Industrial systems, installations and equipment and industrial products –
Structuring principles and reference designations
ISO/IEC 11801-3, Information technology – Generic cabling for customer premises – Part 3:
Industrial premises
ISO 8995-1, Lighting of workplaces – Part 1: Indoor
ISO/CIE 8995-3, Lighting of workplaces – Part 3: Lighting requirements for safety and security
of outdoor workplaces
ISO 11064-3, Ergonomic design of control centres – Part 3: Control room layout
ISO 11064-6, Ergonomic design of control centres – Part 6: Environmental requirements for
control centres
ISO 12100, Safety of machinery – General principles for design – Risk assessment and risk
reduction
ISO/TR 14121-2, Safety of machinery – Risk assessment – Part 2: Practical guidance and
examples of methods
ISO 45001, Occupational health and safety management systems – Requirements with
guidance for use
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 62862-1-1 and
the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
receiver tower
tall structure which supports the receiver and auxiliary systems
3.2
solar power tower plant
solar thermal power plant consisting of a point-focus solar system that is composed of
heliostats, a receiver system, and a receiver tower
3.3
heliostat field
area on which the heliostats are installed to concentrate the solar radiation onto the receiver
3.4
molten salt
inorganic salt in the liquid phase, usually composed of mixtures of alkali nitrates, carbonates or
chlorides

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IEC 62862-4-1:2022  IEC 2022 – 9 –
3.5
annual efficiency of collector system
ratio of the thermal energy transferred to the heat transfer fluid from collector system to the
total direct normal irradiation multiplied by the heliostat field aperture area over a year
3.6
shading loss
energy loss due to the reduction in the effective aperture of the heliostat caused by shadows
cast by other heliostats or the tower
3.7
blocking loss
energy loss due to reflected rays being blocked by adjacent heliostats
3.8
capacity factor
ratio of the number of equivalent operating hours to the total number of hours in a year (8 760)
ratio of equivalent full-load operating hours to the total hours in a year
3.9
heliostat field efficiency
ratio of the solar radiant power incident in the receiver aperture from the heliostat field to the
available radiant solar power over a given period (hourly, daily, weekly, etc.)
3.10
receiver efficiency
ratio of the thermal power transferred to the heat transfer fluid to the solar radiant power incident
in the receiver aperture from the heliostat field over a given period
3.11
cosine loss
energy loss due to the incident direction of sunlight being not parallel to the normal direction of
the mirror surface
3.12
atmospheric attenuation
energy loss due to the reflected rays from the heliostats being absorbed and scattered by the
air before reaching the receiver
3.13
receiver spillage
energy that is reflected from the heliostats but fails to reach the receiver, after deduction of the
blocking loss and the atmospheric attenuation
4 Basic requirements
4.1 For the design of a solar power tower plant, the site resource conditions should be
evaluated considering long-term meteorological conditions at the proposed location of the plant.
As a minimum, the evaluation of average yearly direct normal irradiance (DNI) values (P50 and
P90), typical meteorological year series (P50), ambient temperature, ambient pressure, wind
speed, wind gust and relative humidity should be performed.
4.2 The power block capacity, the storage capacity and the operation modes of solar power
tower plants are determined by a techno-economic evaluation on the basis that the electric
power system requirements are satisfied.

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4.3 For the system capacity matching of solar power tower plants, the following provisions
apply.
a) The overall optimization should be performed between the heliostat field, the receiver
capacity, the steam generator capacity, the steam turbine capacity and the storage capacity.
b) The maximum continuous flow rate of the steam generation system shall match the
maximum turbine inlet steam flow rate.
c) The maximum continuous capacity of the generator shall match the maximum continuous
output of the steam turbine.
4.4 The annual electricity output may be estimated as specified in Annex A.
4.5 The design lifetime for solar power tower plants shall meet customer requirements.
4.6 A uniform identification system should be employed for the plant design and the uniform
identification system employed shall meet the requirements of the IEC 81346 series.
4.7 All computer-based systems shall meet the local information technology requirements for
security protection.
5 Electric power system requirements
5.1 General requirements
The main transformers, circuit breakers and other electric equipment connected to the power
grid shall meet the frequent start-up/shutdown requirement for the plant.
5.2 Requirements for grid-connection
5.2.1 The grid-connection scheme for solar power tower plants shall meet the local
grid-connection requirements.
5.2.2 The voltage class for grid-connection should be selected according to the power plant
capacity, and there should be one or two voltage classes.
5.2.3 Off-load tap-changing transformers should be selected. On-load tap-changing
transformers may be selected as main transformers if the voltage adjustment calculation is
proved to be necessary.
5.2.4 The rated power factor of the generating units of the power plant should meet the local
grid operation demands.
5.2.5 The power quality level at the point of common coupling shall meet the requirements
of IEC TS 62749.
5.3 Relay protection and automatic safety device
5.3.1 The relay protection and the automatic safety device shall meet the requirements of
IEC 60870-5 (all parts).
5.3.2 The configuration of the line protection shall meet the local grid requirements.
5.4 Dispatching automation
5.4.1 Telecontrol information shall meet the requirements of the IEC 60870-5 series.

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IEC 62862-4-1:2022  IEC 2022 – 11 –
5.4.2 The solar power prediction system should be installed at the power plants. The solar
power prediction system should also have the function of upload the data on predicted power,
the direct normal irradiance, the capacity of the thermal energy storage system and other real-
time information to the dispatch.
5.5 Electric power system communication
Electric power system communication shall meet the requirements of the IEC 61850 series.
5.6 Electric energy metering
The electric energy metering device shall meet the requirements of the IEC 62053 series.
6 Solar resource assessment
The solar resource at the site should be assessed according to IEC TS 62862-1-2 and
IEC TS 62862-1-3.
7 Site selection
7.1 When selecti
...