IEEE Electrification Magazine - March 2014 - 16

future revenue sharing between developer and system
host from the provision of ancillary services.

(MW)

4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
0
2013

Middle East and Africa
Latin America
Asia Pacific
Europe
North America

Upgrades to IEEE 1547

2014 2015 2016 2017 2018 2019 2020

Figure 1. The total microgrid capacity, base scenario, world markets
from 2013 to 2020. (Source: Navigant Research.)

today's centralized grid infrastructure. (See "Capturing the
reliability Value Microgrids Provide.") aggregation platforms similar to microgrids will be absolutely necessary if
energy infrastructure follows in the footsteps of telecommunications and the evolution of today's internet. without
a doubt, the existing radial transmission grid will still provide the majority of power supplies to the industrialized
world in the near term. rdeg, nevertheless, will also play a larger role in
providing energy supply, reliability,
security, and emergency care services
when these and other der are networked via microgrids.

The Top Four Microgrid
Drivers Today

Remote microgrids
are networks that
are not typically
interconnected with
any utility grid or
may interconnect
with a highly
unreliable grid.

this article focuses on the four primary reasons why grid-tied microgrids
are moving into the mainstream.
these are briefly described and addressed in more detail:
xx
ieee has played a vital role in
increasing knowledge about technology advances to the broader
engineering community, updating grid protocols to create room for modern
microgrids.
xx
engineering arguments on behalf of microgrids have
also added momentum to a push to recognize advantages attached to medium-voltage dc.
xx
instead of representing the departing load of attractive commercial and industrial (C&i) customers to
utilities, there is a growing recognition that microgrids
can serve as the most reliable form of real-time
demand response (dr) and, if compensated properly,
can lower the environmental (and economic) cost of
voltage and frequency balancing.
xx
Copying successful business models from the solar PV
industry, a growing pool of microgrid developers/integrators is moving forward with power purchase agreement (PPa) contracts, some of which even anticipate

I E E E E l e c t r i f i c ati o n M agaz ine / MARCH 2014

Utility engineers have historically opposed the concept of
islanding, citing safety concerns. this opposition is
embodied in the Underwriter laboratories (Ul) 1741 safety
standard, which was originally devised in 1999 and
requires disconnection of distributed inverter-based generation systems during an outage. Officially titled "the
Standard for inverters, Converters and Controllers for Use
in independent Power Production Systems," Ul 1741 was
updated in 2011 and is now a certification that verifies
which distributed generation units will not backflow onto
the larger utility grid when it goes down. Microgrids challenge that anti-islanding assumption; yet, many new
inverter devices gain Ul 1741 certification and still enable
islanding. this is a clear sign of the schizophrenic relationship der has with utilities and power grids. Fears of being
electrocuted while fixing outages at the distribution level
still shape perspectives on microgrids for many older line
workers in the trenches.
this preconception was most clearly expressed in ieee Standard 1547,
which requires an automatic and rapid
disconnection of all distributed energy
generation during grid outages. For
well more than five years, the ieee
worked on developing a guide on
islanding to round out this series of
standards. this guide, ieee Standard
1547.4, went into effect in July 2011
and is a major step forward for
microgrids. it spells out safe utility protocols for islanding while also putting
into place standards for reactive
power, which will allow microgrids to
sell ancillary services to distribution
utilities. although 1547.4 may not
become a binding standard for utility
operators for another five to ten years, it is a major milestone for this emerging industry.
also approved in 2011, ieee Standard 1547.6 addresses
recommended practices for interconnecting microgrids
with electric power supply distribution secondary networks. among the other related ieee guides in this series
that help build consensus support for the engineering
impacts of microgrids are:
xx
IEEE Standard 1547.5: guidelines for interconnection
of electric power sources greater than 10 MVa to the
transmission power grid.
xx
IEEE Standard 1547.7: draft guide for conducting distribution impact studies for der interconnection. among
the long list of issues relevant to microgrids covered by
this guide are voltage regulation schemes, unintentional
islanding prevention, false inverter trips due to utility

Table of Contents for the Digital Edition of IEEE Electrification Magazine - March 2014