Design of photovoltaic central power station concentrator array

255 Pages·2010·7.41 MB·English

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CONTRACTOR REPORT
SAND82 - 7148
Unlimited Release
• UC-63a
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Design of Photovoltaic
Central Power Station
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Concentrator Array
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Martin Marietta Corporation
Denver Aerospace
Solar Energy Systems
P.O. Box 179
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Denver, CO
Prepared by Sandia National Laboratories Albuquerque, New Mexico 87185
and Livermore, California 94550 for the United States Department of Energy
under Contract DE-AC04-76DP00789
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Printed February 1984
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SAND82-7148 Distribution
Unlimited Release Category UC-63a
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Printed February 1984
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Design of Photovoltaic
Central Power Station
• Concentrator Array
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Martin Marietta Corporation
Denver Aerospace
Solar Energy Systems
P.O. Box 179
• Denver, CO
Under Sandia Contract No. 62-9142
• Abstract
A design for a photovoltaic central power station using tracking concentra
tors has been developed. The 100 MW plant is assumed to be located
adjacent to the Saguaro Power Station of Arizona Public Service. The
design assumes an advanced Martin Marietta two-axis tracking fresnel lens
concentrator. The concentrators are arrayed in 5 MW subfields, each with
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its own power conditioning unit. The photovoltaic plant output is connected
to the existing 115 kV switchyard. The site specific design allows detailed
cost estimates for engineering, site preparation, and installation. Collector
and power conditioning costs have been treated parametrically.
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FOREWORD
• This report presents the design and projected cost of a photovoltaic central
power station utilizing concentrator arrays. The study was undertaken by the
Solar Energy Systems Product Area of Martin Marietta Denver Aerospace.
Arizona Public Service and Stearns-Roger Services, Ltd. served as
subcontractors.
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ACKNOWLEDGEMENTS
They key project personnel of the study were: •
'Sandia Laboratories
Dr. Gary Jones, Technical Monitor
Martin Marietta Denver Aerospace
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Matt S. Imamura, PV Array and System Engineering
Dave Hughes, PV Array and Systems Engineering
Lee Marshall, PV Array and Systems Engineering
Armando Solorzano, Instrumentation, Control and Display
Dr. Patrick Hardee, Instrumentation, Control and Display
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Jerry Stephenson, Power Conditioning
Khaled Sharmit, Array Electrical Design
Bruce Heller, Financial and Cost Analysis
Arizona Public Service
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Eric R. Weber, Program Manager
Thomas C. Lepley, Project Engineer
Stearns-Roger Engineering Corporation
William B. Lang, Program Manager
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L.J. Dubberly, Project Engineer
Don Parker, Civil and Mechanical Engineering
Jim Walton, Electrical Engineering
Jerry Harris, Electrical Engineering
Jack Brock, Cost Analysis
In addition, thanks are extended to John Oster of Burt, Hill, Kosar, Rittleman •
Associates for array installation scenarios, and Joe King of UTC, Power
Systems Division for advanced inverter capabilities.
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Design of Photovoltaic
Central Power Station
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CONTENTS Page
Foreword • i
Acknowledgements ii
Table of Contents iii
List of Figures v
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List of Tables • vi
I. INTRODUCTION • 1
A. Scope and Objectives • 1
B. Design Guidelines/Ground Rules 1
C. Design Summary • 3
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D. Report Format and Acronyms 3
II. PLANT FEATURES AND DESIGN OVERVIEW 7
A. Photovoltaic Power System (PVPS) 9
1. Photovoltaic Array • 14
2. Tracking Structure • 25
• 3. dc Power and Signal Distribution • 28
4. Power Conditioning Unit (PCU) 30
5. Transformers/Switchgear 32
6. PVPS Grounding/Lightning Protection 32
B. ac Electrical System (acES) 35
1. System Configuration 36
• 2. Cabling 39
3. Switchgear. 41
4. Equipment Installation 41
C. Instrumentation, Control and Display System (ICADS) 41
1. RS-232C Interface 45
2. PCU Control Interface 45
• 3. AFC Control Interface 46
4. acES Control and Instrumentation Interface 47
5. Weather Instrumentation 49
6. ICADS Computer Equipment • 49
7. Software. 50
D. Plant F.acilit ies and Services (PFAS) 51
• 1. Services and Utilities • 51
2. Security and Access 57
3. Structures and Enclosures 58
Ill. DESIGN STUDIES AND TRADE-OFF ANALYSIS 60
A. Site Selection 60
• B. Photovo1taic Array • 62
1. Array Sizing • 62
2. Array Field Layout 63
3. Module Construction 64
4. Intermodu1e Cabling 64
5. Lightning Protection 66
• C. Automated Installation • 66
D. Power Conditioning Unit Design 67
E. Field Cabling/Energy Losses 68
F. Intermediate High Voltage Bus 68
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APPENDIXES
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A. Plant Construction Cost Estimate • A-I
B. System Specification • B-1
C. Subsystem and C.om ponent Specifications C-l
D. PV CPS Drawing . D-l
E. Master PV CPS Equipment List E-l
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F. Subfield Performance Simulations F-l
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LIST OF FIGURES
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IC-l Systems Block Diagram ••• 4
IIA System Block Diagram - PVPS 10
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IIA-l Second Generation Module " 14
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IIA-2 Photovoltaic Concentrator Array Assembly 18
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IIA-3 Inverter Efficiency Profile 21
IIA-4 Power Flow Diagram 22
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IIA-5 Source Circuit Wiring Schematic • 24
IIA-6 Wind Tunnel Test Results 26
IIA-7 Concentrator Array Installation .- 29
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IIB-l System Block Diagram - acES • 35
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IIC-l System Block Diagram - ICADS 41
IIC-2 AFC Interface Block Diagram 47
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IID-l System Block Diagram - PFAS 51
IIIB-l Solar Angles and Shading Curves 65
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LIST OF TABLES
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IIA-l Photovoltaic Module Characteristics · · · · · · 15
IIA-2 5 MWe Subfield Characteristic s 22
IIA-3 Cond it ions for Emergency Stow · · · · 27
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IIA-4 dc Cable Power Losses · · 30
IIB-l ac Collection System Power Losses · · · · · · 39
IlC-l Measured and Calculated Data List · · · 43
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IlD-l Typical Well Analysis · · · · 55
IlD-2 Array Washing Concept Assumption 56
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IIlB-l Intermodule Cable Trade-Off · · · · · · · · · · 66
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IlIE-l ac Collection System Power Loss 68
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IIF-l IHV Level Trade Study Results · • · · · · · · · · 69
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I. INTRODUCTION
A. Scope and Objectives
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This document discusses the detailed design of a lOOMWe photovoltaic
central power station (PV CPS) which uses concentrating collectors. This
reference design formed the basis for a detailed plant construction cost
estimate. The reference design and cost estimate were conducted at a
specific utility power plant site, the Saguaro Power Plant owned and
operated by Arizona Public Service (APS) Company. In a parallel effort, a
similar PVCPS was designed using flat panel PV arrays. A plant capacity
• of 100 MWe was recommended by APS. This size was recommended for the
following reasons.
1) A CPS rated at 100 MWe ac output would represent approximately 2.2%
of APS's ~eak generating capacity in 1986 and 2% in 1990.
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2) APS feels that 2% or more of the APS total output power capacity
represents a significant amount of power which can be "felt" on the
utilities high voltage transmission network.
The objectives of this -study were to develop central station reference
• design data that will enable future designers to evaluate potential
system, subsystem, component and interface design options. The extent of
this effort was su ff ic ient to allow detailing of all contributions' to the
plant cost estimate (See Appendix A); specifications of power producing,
distributing and conditioning equipment (See Appendices Band .C);
structural designs, electrical schematics and fielg layouts (See Appendix
• D); a complete breakdown of plant equipment (See Appendis E); and computer
simulation of annual plant performance (See Appendis F). Attention was
given to design of utility interface hardware and integration to ensure
utility acceptance. Wherever possible, existing utility power plant
design and engineering practices were used.
• B. Design Guidelines/Ground Rules
The following set of design ground rules was established with the
technical monitor at Sandia Laboratories:
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Make maximum practical use of the results from Bechtel's subsystem
• tradeoff studies.l Therefore after a careful review of Bechtel's
work and numberous technical interchanges with APS and others in the
photovoltaic systems area, the following criteria were established as
a baseline from Which to work:
SMW array/inverter module subfield
• + 1,000 V dc array bus voltage
Flat plate array spacing of 2.S times panel slant height
34.S kV intermediate high voltage (IHV) ac bus
1 Stolte, w., Bechtel Group, Inc., "Subsystem Design Optimization and Tracie
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Off Study", March 1982.
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