IEC 62862-4-1:2022

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

IEC 62862-4-1:2022 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.

General Information

• Status: Published
• Publication Date: 12-Sep-2022
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 117 - Solar thermal electric plants
• Drafting Committee: PT 62862-4-1 - TC 117/PT 62862-4-1
• Current Stage: PPUB - Publication issued
• Start Date: 13-Sep-2022
• Completion Date: 07-Oct-2022

Overview

IEC 62862-4-1:2022 - Solar thermal electric plants: General requirements for the design of solar power tower plants defines the high‑level design requirements for solar power tower (central receiver) plants. It applies to newly built, expanded or rebuilt installations that use steam turbines and either molten‑salt or water‑steam heat transfer media. The standard addresses technical, safety and planning aspects to support reliable, grid‑connected solar thermal electric plants.

Key topics and technical requirements

IEC 62862-4-1:2022 covers a broad set of engineering disciplines and project phases, including:

• Electric power system requirements: grid connection, relay protection, dispatching automation, metering and power‑system communications.
• Solar resource assessment & site selection: site suitability, resource measurement and data needed for plant design.
• Overall planning and layout: on‑site and off‑site planning, plant master layout and interfaces between subsystems.
• Collector system: heliostat field design, receiver tower layout, heliostat cleaning and maintenance provisions.
• Heat transfer, thermal energy storage and steam generation: design considerations for heat transfer systems, thermal energy storage (TES) using molten salt or water‑steam, and steam generation systems.
• Power block and steam turbine system: arrangement of power block, steam turbine house, auxiliary heating and maintenance facilities.
• Water treatment: feedwater pretreatment, demineralization, cleaning and wastewater handling.
• Instrumentation, control and information systems: automation levels, control room functions, monitoring, video surveillance and information security.
• Electrical equipment: generator, transformers, HV switchgear, AC/DC auxiliary systems, grounding and UPS.
• Occupational safety & health: safety measures, protective facilities and maintenance/inspection access.
• Annexes: informative guidance such as electricity output estimation.

The standard references established IEC publications for rotating machines and transformers (for example IEC 60034-1, IEC 60076 series), aligning power‑generation electrical requirements with recognized electrotechnical norms.

Practical applications and users

IEC 62862-4-1:2022 is intended for:

• Project developers and EPC contractors designing solar power tower plants.
• Mechanical, electrical and controls engineers responsible for plant layout and integration.
• OEMs of heliostats, receivers, thermal storage and steam turbines.
• Utilities, grid operators and regulators assessing plant connection and protection requirements.
• Safety, commissioning and operations teams implementing maintenance, instrumentation and occupational health programs.
• Investors and financiers seeking standards‑based design assurance.

Using this standard helps ensure safe, interoperable, and grid‑compliant solar thermal electric plants, improves project risk management, and supports consistent performance and reliability.

Related standards

Relevant referenced IEC standards include IEC 60034-1, IEC 60034-3, IEC 60076 series and other electrotechnical standards cited within the document for electrical machine, transformer and protection requirements.

Standards Content (Sample)

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

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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

– 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

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

– 4 – IEC 62862-4-1:2022  IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOLAR THERMAL ELECTRIC PLANTS –

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

FOREWORD
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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.

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.
– 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

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

– 8 – IEC 62862-4-1:2022  IEC 2022
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
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.

– 10 – IEC 62862-4-1:2022  IEC 2022
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.

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 selecting a site for a plant, the following factors should be considered: the power
grid structure and the electric power system planning, the auxiliary energy supply, the water
source, the traffic and large equipment transportation, the environmental impact assessment,
the outgoing line corridor, the landform, geology, the seismicity, the hydrology, the meteorology,
the construction, the effect of surrounding companies on the solar power tower plant, etc.
7.2 When the site of a solar power tower plant is selected, the following provisions for the
water supply apply.
a) The water source should be stable and reliable. The water supply should meet requirements
of the long-term water consumption of the power station.
b) If river water is used as water source, the water intake point should be located in the riverbed
section which is stable all year around, so that the impact of mud, sand, vegetation, ice,
drifting sundries and drained water backflow can be avoided.
c) If underground water is used as water source, a hydro-geological investigation report shall
be completed, and it can be subject to local requirements.
7.3 The following provisions for the site's natural conditions apply.
a) The proposed site should be selected in areas with abundant and stable direct normal
irradiance.
b) The site should not be set in a dangerous rock, landslide, karst development, mudslide
section, seismogenic fault or goaf zone. If a geological disaster-prone area cannot be
avoided, in the site selection stage, a geological disaster risk assessment should be
conducted and comprehensively assessed.
c) In the site selection, suspended particulate matter, airport runways and routes, high wind
speed areas, and surroundings with tall and wide trees, mountains, buildings and other
factors should be taken into consideration.
d) Bird habitats and migration routes should be avoided.
e) The proposed site should be located in a flat region.
f) The buildings (structures) inside and outside the power plant should not cast shadow on the
collector during the majority of daytime hours.
g) The proposed site should be away from important, protected cultural relics. The site should
not be located in an open mineral resources area or underground shallow layer mining area
with exploitation value.
– 12 – IEC 62862-4-1:2022  IEC 2022
7.4 During the site selection process, essential data on the geological conditions in the site
area should be obtained, to determine the foundation design scheme of buildings (structures)
in the site.
7.5 The seismic fortification intensity of the site should be determined based on the local
seismic fortification intensity or design ground motion parameters.
8 Overall planning
8.1 General requirements
8.1.1 According to the environmental conditions of sites and the environmental conditions in
the vicinity of sites, an overall planning for the land use, sites and construction area, water
source, water supply and drainage pipelines, auxiliary fuel pipelines, transportation, and
outgoing line corridor, etc. shall be considered in the overall planning.
8.1.2 The overall planning shall minimize the land use to the extent possible. Buildings in the
plant should be grouped into a complex. Construction land shall make full use of interspaces
between plants and the reserved land.
8.2 Off-site planning
8.2.1 The off-site planning shall be based on site location and the main plant processes,
considering the transportation, water supply and drainage, auxiliary energy supply and the
outgoing line corridor according to the plant design capacity and the environmental conditions.
8.2.2 For the transportation planning, the following provisions apply.
a) The transportation planning of the power plant shall be consistent with the environmental
conditions and with the layout design. Local legal requirements can also apply.
b) The access roads shall connect to the existing roads. Access roads should be short and
easy for driving. The access road shall be negotiable for the maximal size and weight of the
equipment supplied.
c) The existing roads should be used for maintenance and inspections of the off-site water
supply and the drainage facility.
8.2.3 The overall planning of the water supply and drainage shall be done according to the
design capacity of the power plant, construction capacity of the current stage, water source,
landform, geology, and environmental protection, etc. The following provisions apply.
a) The feedwater pump rooms, and the feedwater pipelines of the off-site feedwater system
shall be located in reasonably close proximity to the water source. Space should be reserved
for future expansion.
b) The supply and the drainage pipelines should be arranged alongside the existing roads or
planned roads.
8.2.4 The outgoing line corridor of the power plant shall be planned according to the design
capacity of the power plant and the construction capacity of the current stage. The urban and
rural general planning, transmission line directions, voltage classes and loop numbers shall
also be considered.
8.2.5 The auxiliary fuel supply, if required, shall be reliable and stable. And the
transportation method of any such auxiliary fuel supply should be determined after a techno-
economic evaluation of nearby transportation and coordination conditions. The auxiliary fuel
pipelines should be reasonably planned according to the local fuel supply, transportation, and
environmental protection requirements.

8.3 On-site planning
8.3.1 The solar power tower plant site shall be divided into the heliostat field and the receiver
tower; the power block, including the thermal energy storage; and other facilities according to
different process demands. For the general planning, the following provisions apply.
a) Layout design of the heliostat field shall meet the requirements of the site location, solar
energy resource, landform, equipment features, operation modes, and construction and
inspection.
b) The power block should be concentrated around the receiver tower.
c) The receiver tower, turbine house, thermal energy storage, direct air-cooling platform, and
cooling tower should be built in areas with high ground bearing capacity.
d) The auxiliary fuel, if required, shall be stored separately and the storage area shall be
arranged separately. Local safety regulations for fuel storage can apply.
e) Temporary salt storage areas should be provided.
8.3.2 For the corridor planning of incoming and outgoing power lines in the plant, a uniform
planning should be carried out according to the system requirements and outgoing line direction;
crossing of power lines should be avoided.
8.3.3 Local regulations on flood control can apply. When the site elevation is lower than the
high water level in the design, the following provisions apply for flood prevention measures.
a) Local regulations regarding the apron elevation of the turbine house and receiver tower can
apply.
b) The site elevation of the heliostat field shall be determined to meet the requirement that
electric control equipment is not to be submerged by flood.
c) When other flood control measures are taken, the site elevation may be slightly lower than
the high water level in the design.
8.3.4 The power plant vertical arrangement shall be considered taking into account
hydrological and meteorological conditions, flood control (water logging prevention),
engineering geology, production process, etc. The following provisions apply.
a) Landform should be utilized to reduce earthwork quantity.
b) The heliostat field should maintain the original landform. On rugged landform, a wide range
of site formation can apply.
c) The vertical arrangement of power block and other facilities areas may adopt a plane layout
or a step layout.
d) The elevation of buildings (structures) should meet the requirements of production and
maintenance and ensure smooth drainage. The design elevation of the indoor floor should
be determined according to the building function, transportation, drainage and geology
conditions. Local regulations regarding the design elevation of the indoor floor can apply.
e) The minimum gradient and direction shall be designed to drain surface water and match
gutters of the buildings, roads, and site.
8.3.5 The drainage of power plant shall be designed according to landform,
hydrometeorology, engineering geology, underground water level and off-site gutters, etc. The
following provisions apply.
a) The power block may drain water through natural method, road gutters, field gutters or open
trench according to specific conditions.
b) The heliostat field shall employ a natural drainage system, draining water through natural
method or open trench in different zones.

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8.3.6 The site pipelines may be laid out employing burying laying, trench laying and overhead
laying. The pipeline layout shall be planned according to the design capacity, site layout,
vertical arrangement, pipeline features and safety. The following provisions apply.
a) A comprehensive pipe frame may be employed for the power block.
b) The flammable and explosive pipelines shall not cross buildings when unnecessary or cross
other items such as production equipment, auxiliary workshops, storage facilities and tanks,
etc.
8.3.7 Local standards and regulations can apply in terms of road design in the power plant.
In addition, the following provisions apply.
a) Local fire protection requirements regarding the fire lane can apply. Annular fire lanes
should be provided for power block and inflammable explosive areas. Turning radius, width
and clear height of the fire lane shall meet access requirements of fire trucks.
b) The annular fire lanes in the power block and access roads to the power block should be
made of cement concrete or bituminous concrete. The heliostat field should be divided into
different zones. The road width between zones and annular lanes around the heliostat field
should meet the requirements of maintenance and cleaning.
c) The inspection and maintenance roads should be built inside the heliostat field.
8.3.8 Local requirements regarding the enclosure walls can apply.
9 Layout of heliostat field and receiver tower
9.1 General requirements
9.1.1 The layout of the heliostat field and the receiver tower shall be designed and optimized
in accordance with the local conditions such as latitude, topography, and geomorphology.
9.1.2 The annual efficiency of the collector system, location, environmental conditions, field
shape, land utilization ratio, demand curve and shape, time-dependent tariff and atmospheric
attenuation shall be considered for the receiver tower height, distance between heliostats and
receiver tower, and distance between heliostats.
9.1.3 The layout of heliostat field and the receiver tower shall satisfy requirements of both
power block layout and outgoing line.
9.1.4 The heliostat field shall reserve clearance space for inspections and meet the access
requirements for vehicles of installation, inspections and maintenance.
9.2 Layout of heliostat field
9.2.1 Typically, the heliostat field is set out in radial staggered pattern or in unified array
pattern.
9.2.2 The heliostats should be so arranged as to reduce shadowing and blocking losses
utilizing landform.
9.2.3 The aim point strategies of heliostats should establish a radiation flux required by the
receiver at the design point and not exceed the receiver's flux or temperature limits.
9.3 Layout of receiver tower
9.3.1 The location of the receiver tower should be determined by efficiency optimization
calculations for the full TMY (typical meteorological year).

9.3.2 The equipment in the receiver tower and the facilities layout shall be determined
according to process flow and plant overall plan.
9.3.3 The platform's arrangement in the receiver tower shall meet the space requirements
for process, structure, electrics, and fire control.
9.3.4 Stairs shall be installed in the receiver tower and laid out to meet the requirements of
safety and clearance.
9.3.5 The elevator should be installed in the receiver tower, and arranged to meet the
requirements of safety, maintenance, and inspections.
9.3.6 The equipment, facilities and channels in the receiver tower shall satisfy the
requirements of space for pipe installation and heat expansion, to keep a safe distance from
the pipes.
9.3.7 External walls of the receiver tower should have a calibration area.
9.4 Safety protection facilities
9.4.1 A risk assessment shall be carried out to meet the requirements of ISO 12100 and
ISO 14121.
9.4.2 The tower roof shall have an aerial beacon.
9.4.3 The heliostat field should be equipped with devices to drive birds away according to
the environmental impact assessment.
9.4.4 Protections shall be provided for the equipment near the receiver to avoid damage
from solar radiation concentrated by the heliostat field.
9.4.5 The receiver tower and the heliostat field shall be equipped with lightning protection
and grounding devices. The receiver tower and the heliostat field shall meet the requirements
of IEC 62305-1.
9.5 Maintenance and inspection facilities
9.5.1 The inspection area in the heliostat field should meet the needs of the inspection
vehicle, parking of lifting equipment and temporary storage.
9.5.2 The roads in the heliostat field and distances between heliostats shall meet the
requirements for inspection and maintenance equipment.
9.5.3 Devices in the receiver tower, valves and instruments shall be arranged so as to be
easy to maintain and inspect. Platforms and stairs should be built for areas requiring
maintenance and inspection.
9.5.4 The receiver tower should be equipped with a hoist for overhaul.
10 Layout of power block
10.1 General requirements
10.1.1 The power block layout scheme shall be adapted to the production process, installation,
operation, and overhaul. Equipment arrangement and organization should be reasonable and
compact. Pipe and wire connections shall be short, neat and with few crossings.

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10.1.2 The power block should adopt centralized or combined arrangement so that functional
zones are clear and system connections are simple. The turbine area and feedwater heaters
including the deaerator area should be arranged compactly. Heat transfer, thermal energy
storage and auxiliary hea
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