IEEE Power & Energy Magazine - November/December 2019 - 82

the large number of units and higher communication costs;
these costs need to be kept in perspective as related to the
investment per unit. In addition, requirements for small DERs
focus more on local effects, such as anti-islanding or voltage
control at long feeder lines. Some of these requirements even
contradict the system specifications. For example, large plants
should ride through a wide range of frequency deviations,
while small DERs often use frequency deviations to detect an
unintended islanding event and shut down immediately if the
detected frequency is outside a narrow band. With increasing penetration, DERs become as relevant for system security
as large plants. Therefore, new requirements for DERs need to
address both local effects and system-wide responsibilities. As
some of the requirements are contradictory, a compromise is
needed for standards and grid codes of DERs, balancing reliability needs, equipment capabilities, and cost.

IEEE 1547
IEEE Standard 1547 is a series of standards originally approved
in 2003. It establishes criteria and requirements for interconnection and related testing of DERs with aggregate capacity of
10 MVA or lower to an electric power system (EPS) at typical
primary and/or secondary distribution voltages (Figure 2).
The first version of IEEE 1547 (IEEE 1547.1) was issued
in 2005. It defined the conformance test regimens for DERs to
confirm that components, subsystems, and/or systems intended
to be interconnected with the EPS comply with IEEE Standard
1547-2003. In 2014, IEEE 1547.1 was amended to address issues
that had arisen from experience gained from the ever-increasing
penetration of DERs. It allowed DERs to participate in EPS
voltage regulation and revised abnormal voltage and frequency
protection thresholds and clearing times. IEEE 1547.1 was subsequently amended in 2015.

Area EPS
PCC

PCC

Local EPS 1

PCC

IEEE P2800
Point of DR
Connection

Load

Distributed
Resource
(DR) Unit
Local EPS 2

Point of DR
Connection

DR Unit

Load

Local EPS 3

Note: Dashed lines are EPS boundaries. There can be any
number of local EPSs.

figure 2. The relationship of interconnection terms. PCC:
point of common coupling.
82

A full revision of the IEEE 1547 standard was issued in
2018 to address further DER expansion. It considered ongoing
technological advancements and addressed interoperability as
deemed necessary to enable the development of the smart grid.
IEEE Standard 1547-2018 made a significant advancement
in standardizing the interconnection and interoperability of
DERs connected to local distribution networks. It addresses
the "performance, operation, testing, safety considerations, and
maintenance of the interconnection." This includes general
requirements, response to abnormal conditions, power quality,
islanding, and other aspects. The requirements set forth in the
standard "are universally needed for interconnection of DER,
including synchronous machines, induction machines, or power
inverters/converters." The IEEE P1547.11 project is exploring the
testing and verification of these requirements as well.
IEEE Standard 1547-2018 defines performance requirements
and capabilities with default settings as well as ranges of adjustability. Utilities and state regulatory entities should evaluate and
select appropriate performance categories and settings to suit
their system's characteristics. This involves coordination among
these entities and reliability coordinators, independent system
operators, transmission operators, transmission planners, and
planning coordinators on those issues pertaining to bulk power
system (BPS) reliability and performance. The requirements
set forth in IEEE 1547-2018 foster this collaboration among the
local utility and entities with a regional or wide-area view to
ensure some uniformity in settings that affect the BPS.
Any existing rules, regulations, or utility interconnection
requirements based on IEEE Standard 1547-2003 should be
updated to show the current requirements in IEEE 1547-2018
reflecting appropriate selection of DER settings. Experience
around the world has proven that retroactive changes to installed
resources can affect many stakeholders and be extremely costly
and complicated. On the other hand, clearly defining DER settings in interconnection rules can improve efficiency, reduce
costs, maximize hosting capacity and efficient use of the existing network, and ensure the reliability of the local distribution
systems and the BPS.

ieee power & energy magazine

The recently established IEEE P2800 team is developing a standard for interconnection and interoperability of inverter-based
resources interconnecting with associated transmission EPSs.
This standard will establish "the recommended interconnection capability and performance criteria" for these resources
interconnecting at both the transmission and subtransmission
system. The standard, similar to IEEE 1547-2018, will provide
"recommendations on performance for reliable integration of
inverter-based resources into the bulk power system, including,
but not limited to, voltage and frequency ride through, active
power control, reactive power control, dynamic active power
support under abnormal frequency conditions, dynamic voltage support under abnormal voltage conditions, power quality,
negative sequence current injection, and system protection."
The P2800 team has an aggressive schedule to complete this
november/december 2019

IEEE Power & Energy Magazine - November/December 2019

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - November/December 2019