Power Systems
Large Scale and Micro-Grid
NREL - Golden Colorado
7/16/2014
Team Leader:
Sal Sferrazza
Electrical Engineer
NREL
Safety Engineer
Principal Engineer
Principal Manager
Electrical Coordinator
Principal Engineer
President
Engineer
Engineer / Safety Officer
Code Inspector/NFPA 70 E
Army Research Laboratory
Brooks Engineering
ESC Engineering Inc.
Lawrence Livermore Nat. Lab
Brookhaven Natl. Lab
Electrical Safety Consulting
Savannah River – DOE
Las Alamos National Lab
Pantex – Consolidated Nuclear
Team Members
Nancy Vyas
Bill Brooks
Chris Brooks
Edward Chesney
Thomas Nehring
Bernie Ruffenach
Brian Sautter
Eric Stromberg
John Stultz
This Working Group focused on the following electrical
safety issues, with diverse sources and storage of energy:
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Interconnection
Distribution
Assessment of Hazards
 Arc Flash Risks
 Shock Risks
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Signage - Warnings
Fault assessment and mitigation
Energy storage systems
Procurement and Acceptance criteria
Maintenance and Operations
 Procedures and Policies
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Control of all Electrical Sources
 PPE
 LOTO
Micro-grid: A localized grouping of electricity sources
and loads that can operate autonomously or can be
connected to the utility grid
Large Scale: A power system that is under the control of
the utility system operator
Power System: A power source or group of sources that
work together to supply electrical loads
Power Source: Equipment that converts non-electrical
energy into electrical energy to be used in a power
system
Utility System: A power system that is regulated by a
public utility commission
Service: The conductors and equipment for delivering
electric energy from the serving utility to the wiring
system of the premises served
Identified applicable codes, standards and procedures for
electrical power sources within DOE sites
 Design guidance related to operation and maintenance
 Interconnection – IEEE 1547, local utility, ISO, FERC, NERC
 PV standards – UL 1703, UL 1741, UL 61730, UL 2703, UL 62109
 Construction / installation guidance
 NFPA 70 (NEC) Chapters 1-4 and Articles 690, 692, 694, 701, 702,
705
 NECA 1
 NESC (IEEE C2)
 NFPA 70E
 OSHA 1926 Sub Part E, K, M, V
 NFPA 780 (Lightning protection)
 Equipment Manufacturer – instructions/guidelines
Identified applicable codes, standards and procedures
for electrical power sources within DOE sites
continued
 Operation and maintenance guidance (qualified and
authorized)
 OSHA 1910.269 Subpart I, R (269)
 NFPA 70E
 NESC (IEEE C2)
 Interconnection requirements (IEEE 1547, local utility, ISO,
FERC, NERC)
 Equipment Manufacturer – instructions/guidelines
Codes and Standards currently under development
 PV standards – ASTM ICOMP WK43549 (O&M);
2017 NEC Article 690 / 691(Proposed)(Large Scale PV
Plants); Ground-fault protection upgrades; arc-fault
protection upgrades
 Wind standards and papers, “Arc-Flash Hazard in Wind
Power Plants,“ among 11 existing papers that may be
rolled into an IEEE guide
Needed Codes, Standards, and revisions
 NFPA 70E (need better information on dc Arc Flash
calculations for PV, batteries, capacitors)
 Guidance on fault contribution of site sources
 Specific guidance for special locations (e.g. altitude,
lightning, corrosion, dust, temperature extremes,
humidity extremes)
Develop Electrical Safety Checklists:
 Micro Grid System
 Power Sources
 Solar Photovoltaic System
 Energy Storage System
 Battery
 Flywheel
 Inductors/Capacitors
 Fuel Cell System
 Wind Power System
 Hydro Power System
Develop Electrical Safety Checklists:
continued
 Internal Combustion Power System –
Renewable and Non-renewable (e.g. Diesel, Natural Gas, Biofuels)
 Reciprocating
 Gas Turbine
 Steam Power System (Geothermal, Biomass,…)
 Types of Power Converters
 Static Power Converter
 Inverter
 Rectifier
 Rotating Power Converter
 Induction
 Synchronous
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Suggested for Future Best Practices
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Micro Grid Safety Design Checklist
Solar Photovoltaic Safety Checklist
Battery Safety Checklist
Controls Safety Checklist
Generators Safety Checklist
 Renewable
 Non-renewable
 General System Operation
Applicable Code References for DOE Sites
For contractor work rules at power sources on DOE
sites

OSHA 1910.269 (a)(3)(iii) - “The contract employer and
the host employer shall coordinate their work rules and
procedures so that each employee … is protected ….”

OSHA 1910.269 Appendix E – Table 2 (Arc Flash
Assessment – examples of acceptable methods)
 NFPA 70E
 IEEE 1584
 Commercially available software programs
Questions ?