Page 18 - North American Clean Energy January February 2014

wind power

Evolving Codes

Ensuring wind

turbine safety

By Kenneth Boyce, UL LLC

Wind power generation resources continue to grow in North

America and around the world, now representing a signiicant
proportion of new electrical power capacity. In cases of rapid

development and deployment of energy infrastructure—such

as what is happening with new wind power resources—

standards become a critical foundation.

Standards deine consistent market expectations, performance benchmarks, and

fundamental design features—and, most importantly, safety. As more turbines are
installed, new technologies are introduced and the existing turbine population ages. Safety
standards provide guidelines and support to ensure optimal design and performance of
a safe and secure infrastructure. With this goal in mind, wind turbine standards are in a

dynamic state of development.

Setting the standards
he International Electrotechnical Commission (IEC) has published the IEC 61400 series

of standards to specify essential design requirements for the engineering integrity of wind
turbines. he standards cover many important aspects of the design, installation, and use
of wind turbines.

Recognizing the complexity of turbines as sophisticated electromechanical apparatus,
it’s notable that only a small section of the IEC requirements focus on the electrical safety
of the equipment, controls, and protection. Although the IEC requirements establish the
need to evaluate most critical concepts of turbine design, as presently written they do not issues outlined here, these standard eforts recognize there are some unique North

provide detailed guidance on how to evaluate.
American issues, which require special consideration beyond the IEC standards. hese
To support the development of the best worldwide requirements for safety and include issues such as the fundamental diferences between the installation requirements
performance, IEC Technical Committee TC 88 has agreed to a project to review any of the IEC 60364 series and the prevailing US codes (such as the NEC), as well as the
potential enhancements to the electrical safety requirements. IEC’s eforts will continue to recognized diferences in other important North American safety requirements.

progress over the coming years and, so far, there has been signiicant activity within North American National Standards for safety are known for supporting compliance with
America. Collaborative development of North American safety requirements for wind the requirements for exporters, buyers, owner/operators, and other involved parties,
turbine systems not only includes product safety standards, but also installation codes.
and compliance is an important measure for demonstrating due diligence in addressing
workplace and consumer safety, supporting equipment installation and acceptance, and

Raising the bar
establishing conidence among customers.
he National Electrical Code (NEC), ANSI/NFPA 70, addresses safe installation of systems he American National Standard for safety of small wind turbines was jointly published
and equipment that aren’t under the exclusive control of a utility, as addressed by speciic last year as ANSI/UL 6142/AWEA 6142*. he ANSI/UL 6141 Standard for Safety for Large
requirements in Section 90.2. Published several months ago by the National Fire Protection Wind Turbine Systems is presently under development. Developed using a balanced,

Association, the 2014 Edition of the NEC contains important new requirements for safety consensus-based approach, they are established by standards panels comprised of
of wind turbine installations in Article 694, “Wind Electric Systems.”
equipment producers, users, technology experts, scientists, regulatory authorities, and
his new edition applies to all wind systems under the purview of the NEC regardless other technical experts with an interest in wind turbines.
of rating, eliminating the previous scope limitation to cover only turbines having a rating Both standards contain fundamental requirements related to wind turbine safety. hese

up to 100 kilowatts (kW). Another addition requires that wind systems be certiied for include important safety features, such as the electrical safety of the turbine and internal
the application. One of the new revisions also expands on the previous limitation for a subassemblies, as well as the functioning of critical aspects of the control and protection
maximum of 600-volt rating for wind systems for dwellings, to allow systems up to 1000 systems. hey don’t, however, cover mechanical or structural integrity of the wind turbine
volts for other applications.
system or subassemblies, which are coordinated with the mechanical and structural

To promote safe design and easy installation of wind turbines, several wind turbine limitations speciied in established performance and safety standards (such as the IEC
safety standards have been collaboratively developed. In addition to the electrical system
61400 series).

18 nacleanenergy.com
JANUARY/FEBRUARY 2014