Potential Impacts of Smart Grid on Fire Protection Engineering
By Frederick W. Mowrer, Ph.D., P.E., FSFPE, Lonny Simonian, P.E., Thomas M. Korman, Ph.D., P.E., and David C. Phillips | Fire Protection Engineering
Historically, the generation,
transmission, and distribution of electricity has largely been a one-way
process, with electrical service providers sending electricity to
consumers with little or no feedback from the consumer sites. That model
is changing, however, with the modernization of the electricity
delivery system to provide two-way communication between providers and
consumers as a means to monitor and, in some cases, regulate electrical
distribution. Another change is the more widespread use of on-site
electrical generation, distribution, and storage systems.
These changes fall under the umbrella of
what has become known as the "Smart Grid. " The purpose of this article
is to address some of the potential electrical and fire safety impacts
of the Smart Grid that were identified as part of a research project
conducted at the California Polytechnic State University (Cal Poly) on
this topic (see sidebar).
WHAT IS A SMART GRID?
Under the Energy Independence and
Security Act of 2007, the National Institute of Standards and Technology
(NIST) has "primary responsibility to coordinate development of a
framework that includes protocols and model standards for information
management to achieve interoperability of smart grid devices and
systems…."1 Furthermore, NIST defines the term "smart grid" as:1
"a modernization of the electricity
delivery system so it monitors, protects and automatically optimizes the
operation of its interconnected elements – from the central and
distributed generator through the high-voltage transmission network and
the distribution system, to industrial users and building automation
systems, to energy storage installations and to end-use consumers and
their thermostats, electric vehicles, appliances and other household
In this context, "thermostats, electric
vehicles, appliances and other household devices" may be considered
"utilization equipment." There are a wide range of energy management
applications and electrical service provider interactions, including:
Peak demand management
Forward power usage estimation
Load shedding capability estimation
End load monitoring (sub metering)
Power quality of service monitoring
Utilization of historical energy consumption data
Responsive energy control
A Smart Grid Conceptual Model can be
portrayed as a set of diagrams and descriptions that are the basis of
discussing the characteristics, uses, behavior, interfaces, requirements
and standards of the smart grid.1
This conceptual model, shown in Figure 1,
provides a context for analysis of interoperation and standards for the
development of the smart grid architecture.
Figure 1. Smart Grid Conceptual Model1
Figure 2. Smart Grid Customer Domain1
Within this model, "customers" are
defined as the end users of electricity, but they may also generate,
store, and manage the use of energy. Traditionally, three types of
customers are identified, each with their own domain: residential
(home), commercial (building/commercial), and industrial. In addition,
the end user may be an institutional customer (such as schools,
hospitals, etc.). This project focused on the end user, or customer, in
the built environment as shown in Figure 2.
Implementation of the smart grid changes
the nature of the electrical distribution system in ways that have a
number of safety implications, including personnel, electrical, and fire
safety. Because of these safety implications, it is important that
relevant safety codes and standards, such as the National Electrical Code,2 stay abreast of smart grid developments.
Before the smart grid, electrical power
distribution to customers was largely a one-way process, with customers
receiving electrical power generated at a bulk generation plant which
was then transmitted and distributed via the existing grid. Under this
scheme, a limited amount of instrumentation data could be transmitted
from a customer to the service provider and, in some instances, remote
control could be executed, such as remotely turning off residential air
conditioners during periods of peak demand.
Under the smart grid, electrical power
generation and distribution become a two-way process between the
customer and the grid. To work effectively and safely, the processes of
power generation and distribution, as well as those of instrumentation
and control, must be closely coordinated and managed.
SMART GRID TECHNOLOGIES
Current and emerging smart grid
technologies were reviewed and the implications that these technologies
may have upon the built environment (such as a facility's safety
features) were assessed wherever the National Electrical Code2
(NEC) has jurisdiction. This included all power distribution and
control systems throughout a facility. Specific areas of focus were:
The electrical service or utility point of connection interface (smart meter)
Energy generation and micro-generation
systems (such as photovoltaic cells, wind power, micro hydro, emergency
and standby generators, and fuel cells)
Energy conversion/storage systems (such
as batteries, uninterruptible power supplies (UPS), and thermal energy
Community energy storage
Customers who adopt smart grid technology
gain control over the amount and time of electrical load consumption.
For residential customers, the smart meter is typically installed by the
utility or service provider, and the customer may acquire additional
devices/systems to take advantage of the information and communication
provided by the meter.
example, if these customers switch to a time-of-use pricing system,
they can benefit by shifting non-time-specific loads to cheaper times,
optimizing micro-generation systems for maximum output at high price
times, and using on-site storage to supply the grid or the home at
high-price times. The commercial customer may acquire additional
devices/systems to take advantage of the information and communication
provided by the meter.
Possible NEC Issues
A meter that monitors and
automatically reports a customer's electricity consumption to the
utility. Smart meters may also interface with customer's energy systems
and devices to provide the customer with additional information,
communications with the utility, and demand response or load shedding
Increased wiring for communications
Life-safety circuits must not be affected by load shedding
Increased load center wiring
Adequate grounding and bonding provisions
Sensors for connecting smart meters and major electrical loads
Harmonics induced from Class 2 wiring
Life support equipment
Energy Micro-Generation, Co-Generation, and Generation Systems (EMGS)
Some grid-connected electricity
customers have the ability to generate their own electricity through
photovoltaic systems, fuel cells, backup generators, etc. These systems
may be used to power the customer's equipment or add energy to the grid,
especially during peak hours for economic incentives or to help with
load shedding. Currently, however, backup generators are not normally
permitted to supply power to the grid.
System interconnection requirements
Protection for fuel to energy conversion
DC from an EMGS to a building
Manual disconnect switches
Grounding system interconnection
Excess generation contingencies
Manual override of automatically controlled circuits
Use of DC from EMGS by consumers
Conversion of DC to AC for use or transmission to the grid
Limitations on inverter harmonics
Energy Storage Systems (ESS)
Storage systems may be used by
customers to reduce demand during peak hours, as a backup in case of
grid failure, or as a way to increase the flexibility of renewable
Overcharging of storage systems
Charging and discharging of ESS
DC to AC conversion for use or grid supply
Fuel cell placement and clearance
These vehicles have an energy storage
system on-board. The storage can be charged by connection to the grid
and may be able to supply the grid if needed.
Battery charging and consumption meter/controller installations
Vehicle-to-Grid storage system charging and discharging
Charging and discharging
Community Energy Storage (CES)
A local energy storage with limited
backup time that is available to a small group of customers. CES units
allow excess energy from the customers to be captured and later
Voltage flicker provisions
CES unit guidelines
CES unit placement guidelines
Grounding and bonding provisions
Table 1. Summary of Smart Grid Technologies
Table 1 provides a summary of theses
smart grid technologies and provisions that may need to be addressed by
REVIEW OF NFPA 70
Based upon an assessment of current and
emerging smart grid technologies, a review of the NEC was conducted and
NEC sections were identified as candidates for revision. Some of these
code sections may require revisions to address smart grid monitoring or
control, such as chapter 4, "equipment," and chapter 6, "special
equipment," while other code sections may require revisions due to
utility interfaces (chapter 1, "general," and chapter 2, "wiring and
protection"), emergency power (chapter 7, "special conditions"), or
wired/wireless communication (chapter 8, "communication systems").
Table 2 links recommended code revisions to technologies that have evolved to prompt the change.
work was made possible by the Fire Protection Research Foundation (an
affiliate of the National Fire Protection Association). The authors are
indebted to the project steering committee members, smart grid task
group members, and industry representatives for their valuable
W. Mowrer, Lonny Simonian, Thomas M. Korman and David Conrad Phillips
are with the California Polytechnic State University.
Smart Grid and NFPA Electrical Safety Codes and Standards
In 2009, NFPA was invited to
participate in the National Institute of Standards and Technology (NIST)
smart grid rapid standardization initiative to ensure that the safety
of built infrastructure was appropriately addressed. This was a
proactive initiative to ensure that National Electrical Code2
(NEC) and other NFPA electrical safety standards kept pace with smart
grid developments. An NFPA smart grid task force was formed and a grant
request submitted to NIST for focused support of task force activity.
This included accelerating interoperable codes and standards development
for the smart grid. The grant request was approved in the summer of
Project research objectives included:
Technology Review and Safety Assessment of
the emerging technologies associated with smart grid implementation and
their impacts on the safety features of the built environment
Regulatory Development and Needs Assessment of
current weaknesses/gaps in the U. S. fire and electrical safety codes
and standards which will impede widespread implementation of this
needed specific codes and standards development/changes and areas where
additional data/research on safety aspects is required
The project has received broad
support from the fire protection community. The project steering
committee consisted of members representing the National Electrical
Manufacturers Association, Underwriters Laboratories Inc., International
Association of Electrical Inspectors, International Fire Marshals
Association, NEC Correlating Committee, Schneider Electric Company,
NIST, National Fire Protection Association, and CSA-International.
A two-day industry workshop was
conducted in Washington, D. C., in mid-March of 2011 to review
preliminary results and solicit input from leaders within the NFPA
safety standards development community on the project. The NEC Smart
Grid Task Force also provided comments in consideration of the upcoming
NEC code-change cycle.
The outcomes of the project included:
The final report,5 which is available for free download at nfpa.org/foundation – This will form the technical basis for submitted NEC changes related to the smart grid
A 20-page inspector's guide6
Presentations at IAEI section meetings
Plans for future webinars
"Report to NIST on the Smart Grid
Interoperability Standards Roadmap," Electric Power Research Institute
(EPRI), Palo Alto, CA, 2009.
NFPA 70, National Electrical Code, National Fire Protection Association, Quincy, MA, 2011.
NFPA 110, Standard for Emergency and Standby Power Systems, National Fire Protection Association, Quincy, MA, 2010.
NFPA 111, Standard on Stored Electrical Energy Emergency and Standby Power Systems, National Fire Protection Association, Quincy, MA, 2010.
Simonian, L., Korman, T., Mowrer, F.
& Phillips, D. "Smart Grid and NFPA Electrical Safety Codes and
Standards," Fire Protection Research Foundation, Quincy, MA, 2011.
"A Guide for the Electrical Inspection
Community," Fire Protection Research Foundation, Quincy, MA, 2011.
NFPA 70E, Standard for Electrical Safety in the Workplace®, National Fire Protection Association, Quincy, MA, 2012.
SFPE is a global organization representing those practicing in the fields of fire protection engineering and fire safety engineering. SFPE’s mission is to define, develop, and advance the use of engineering best practices; expand the scientific and technical knowledge base; and educate the global fire safety community, in order to reduce fire risk. SFPE members include fire protection engineers, fire safety engineers, fire engineers, and allied professionals, all of whom are working towards the common goal of engineering a fire safe world.