IEEE Power & Energy Magazine - March/April 2017 - 94

Frequency (Hz)

61.0
60.9
60.8
60.7
60.6
60.5
60.4
60.3
60.2
60.1
60.0
59.9
59.8
59.7
59.6
59.5
59.4
59.3
59.2
59.1
59.0

Frequency Distribution Plot August 2016

100

1,000
10,000
Duration (s)

100,000 1,000,000

figure 3. Hawaiian Electric power system frequency distribution in August 2016.

50-MW generating station at Schofield
barracks, an Army installation located
in central Oahu. When completed,
this facility will be the only source of
firm generation on the island located
inland, away from potential storm or
tsunami impacts.
The Schofield barracks generating
station provides flexibility in several
ways. It will feature six modern and
efficient 8.4-MW reciprocating internal
combustion engines that complement
increasing levels of solar and wind power on the Oahu grid. In sum, the combustion engines can output as low as
4 MW up to 50 MW, a more than 12:1
turndown ratio. In addition, the generators feature the capability to quickly start up (to full load within 6 min),
shut down and cycle off multiple times
a day, ramp up and down to keep pace
with sudden changes in solar and wind
energy resources, or black start the grid
by restarting other power plants in the
event of an island-wide outage.
In normal operating conditions,
these biofuel-capable generators will
supply renewable power to all customers and contribute to both the military's and the state's renewable energy
targets. More significantly, in the event
of an emergency, the combustion engines have the capability to power a

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microgrid that will run the Army's facilities in support of its missions.
New technology is a key component in achieving our renewable energy
goals, and that is demonstrated by our
ongoing commitment to modernizing
the grid. We have partnered with Santa
Clara-based Varentec and Boston-based
Gridco Systems to test their distributed
grid control technology as a means of
mitigating the voltage regulation impacts high-rooftop PV penetrations can
have on the distribution system.
Varentec's Edge of Network Grid
Optimizers and Gridco Systems' In-line
Power Regulato are power electronic
devices installed on the low voltage side
of the distribution system to reduce the
voltage volatility caused by rooftop PV
generation. Each device is paired with
its respective software analytics platform, which can control the devices and
provide information to grid operators.
These partnerships demonstrate innovation in the power electronic technology
itself and in the application of the technology to safely integrate higher levels
of distributed resources.
Collaboration and innovation depend on finding common ground
among stakeholders with diverse interests. With the Schofield project, the
common benefits are easy to define.

In other cases, where shared benefits
may not be as obvious, effective communication is needed to break down the barriers of potentially divergent interests.
To address requirements for advanced
inverters, for example, a technical working group comprised of utility and rooftop solar industry representatives was
created to help focus on grid issues specific to Hawai'i.
Using actual data from the field, the
working group participants exchanged
information to gain a better understanding of how existing technologies were
being challenged, leading to a clear focus on the problems to be solved. As a
result, the working group produced progressive solutions that improved ridethrough capabilities and developed additional advanced inverter functions and
standards for Hawai'i.
Timely, clear communication with
customers throughout the PV installation process is also imperative to ensure
that the utility is seen as a partner and
problem solver rather than as an impediment. Educating consumers about
how their system interacts with the grid
will potentially lead to greater support
on public policy issues.
Distributed energy resources are
here to stay. Integration of large quantities of DERs will present challenges,
whether they involve voltage regulation,
balance of supply and demand, or flexible distributed generators. And these
challenges can't be resolved alone. We
must bring together state agencies, renewable energy developers, and policy
makers to deliver adaptive grid products
and services that enhance DER value
for customers.
Whenever common ground can be
identified, customer demands for DERs
and grid modernization will present opportunities for collaboration, innovation,
and, if executed successfully, increased
trust and confidence in the capabilities
of the local utility. These opportunities
can serve as a bridge to accommodate
emerging technologies and solve renewable energy integration challenges.
p&e

march/april 2017

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2017