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WORLD-GENERATION NOVEMBER/DECEMBER 2016
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PERSPECTIVE
INTRODUCTION
The electrical grid in the United States
is heavily regulated to ensure reliabile and
cost effective electricity for consumers. As
the U.S. electrical grid continues to evolve
by adopting new business models,
integrating renewables, and incorporating
smart grid technologies, maintaining
system reliability takes significant
coordination and oversite. The Federal
Energy Regulatory Commission (FERC) is
an independent regulatory body that
oversees the transmission network with the
main objective of promoting a safe, reliable,
and efficient grid for the energy
consumers. Through the establishment of
FERC rulings, this entity is able to set
operational standards and precedence for
how the transmission network will operate.
In a landmark ruling issued on June 16,
2016, FERC Order No. 827 will now
require all newly interconnected non-
synchronous generators such as wind
farms “to be able to provide reactive power
at the high-side of the generator substation
as a condition of interconnection”. Prior to
this ruling wind farms and other non-
synchronous generators were exempt from
providing any reactive power compensa-
tion, unless a need was identified through a
system impact study.
This article will address the
significance of the FERC 827 and the
solutions available today to help facilitate
the seamless interconnection of wind and
solar plants to the transmission network.
BACKGROUND
With declining costs of renewables,
extension of subsidies in the form of tax
credits, and policies promoting low
emitting fuel sources, renewables are
becoming a mainstream source of
generation on our electrical grid. In order
to maintain our system reliability, the rules
that govern our grid interconnection
policies need to be constantly evaluated
and revised to make certain that variable
and intermittent sources of power can
safely connect to the utility grid. As a
result, over time FERC has issued rulings
that set standards for interconnecting to
the transmission network and verify that
these generating facilities would also
contribute to the operational performance
of the grid.
In 2003, FERC issued Order No. 2003
which set “governing procedures and a
standard agreement for the interconnection
if generators greater than 20 MW.” With
the goal of preserving system reliability,
FERC Order 2003 placed performance
requirements on generation facilities such
as the ability to demonstrate low voltage-
ride through, include supervisory control
and data acquisition (SCADA) ability to
transmit data, and maintain a power factor
within the range of 0.95 leading and 0.95
lagging at the point of interconnection. This
standard procedure and agreement for
interconnection of large generation
facilities was established to ensure bulk
system voltage regulation was maintained
and not compromised.
In order to reduce barriers to the
adoption of wind power, FERC adopted
another ruling to prevent added
“unnecessary obstacles to further
development of non-synchronous
generators.” FERC Order 661 essentially
exempts wind farms from meeting the
interconnection requirements established
in FERC Order 2003 unless the
transmission provider shows through a
system impact study shows that “meeting
such requirements is necessary to ensure
safety or reliability”.
However, as more and more rigid
operators were adopting wind and solar
power generation, the need for these non-
synchronous generation facilities to
contribute to the reactive power support of
the utility grid has increased significantly.
In addition to the high penetration of
renewables, regulators have also
determined that costs to help wind
generation facilities to meet reactive power
requirements have gone down substantially
since the first ruling was launched back in
2003. As a result, in June 2016, FERC
issued a new ruling that will now require
all non-synchronous generators connecting
to the transmission network 20 MW or
larger to provide dynamic reactive power
within the power factor.
THE IMPORTANCE OF REACTIVE POWER
Today‘s electrical grid predominately
operates on alternating current (AC)
power, where watts that are generated,
transmitted, delivered and consumed are in
the form of real power. However, there is
another form of power that is inherent to
AC electrical grids, and that is called
reactive power, which is measured in vars.
Reactive power does no real work on the
electrical grid as in turning on the lights or
charging a mobile phone, but whether it is
useful or not, reactive power is generated
and consumed all throughout the electrical
grid.
Reactive power is generated and
consumed by equipment throughout the
transmission and distribution grid such as
transformers, capacitors, reactors and
motors. Left unchecked, too much reactive
power can overheat electrical equipment
and wires and lead to increased line losses.
At the same time, too little reactive power
NEW FERC 827 RULING FOR WIND FARMS
ENSURES SMOOTH GRID CONNECTIONS
BY MICHELLE MEYER,ABB
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