IEEE Power & Energy Magazine - March/April 2018 - 73

DSDR Mode
DSDr is an innovative, one-of-a-kind peak load reduction
tool that meets the reliability and sustainability requirements
of traditional generation resources. It was built around the
well-known utility industry concept of conservation voltage
reduction, in which a reduction of distribution system voltage produces a corresponding and comparable reduction in
demand. DEP's idea to use this as a means for deferring peak
generation originated through the completion of a 2002 distribution automation study by a consultant hired by the company. the study indicated the possibility of a 3.7% voltage
reduction-through the optimization of voltage regulators
and capacitor banks-resulting in an estimated load reduction of over 300 Mw during peak conditions. a detailed
business-case analysis yielded the cost justification and a
targeted time frame for delivering the benefit of DSDr; the
project implementation phase soon followed.
However, the goal was still just a theory that had not been
attempted before and required technology that either did not
exist or was still being developed. It necessitated ingenuity, collaboration, and thousands of dedicated work-hours from multiple departments and partnering vendors. the journey to make
DSDr a reality involved many parallel and equally important
efforts (not all of which, unfortunately, can be discussed in
detail within the scope of this article). we, therefore, selected
the history that helped lay the foundation and a few key technical aspects-some of which have already been covered or summarized in previous sections-as our focus here.
march/april 2018

1,800

1,600

1,400

1,200

1,000

800

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400

LV Sensor Data: 7 January 2014

200

126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
108

Voltage (V)

demand-side management assets, including its large load curtailment rider and water heater and strip heat-load control, and
issued an appeal to customers and employees for conservation.
Operators also decided to use emergency mode level 1 as a
planned peak load management tool starting at approximately
7:00 a.m. It should be noted at this point that DSDr was still
in a testing and evaluation phase, and emergency mode hadn't
previously been used in this manner or considered an option
for the winter peak season. Operators subsequently activated
emergency mode level 2 at approximately 7:58 a.m. the mode
remained active until close to 9:30 a.m, which was after the
system load had demonstrated a continual decline once it
exited its peak.
thus, aDMS-in combination with the other utilized
resources-enabled DEP to serve an all-time peak demand
without having to shed any firm load. this also marked the first
time in the history of the company that a 5% voltage reduction
had been remotely implemented system-wide. an ancillary benefit of the use of the mode was the collection of data from new
SCaDa devices that had been installed for DSDr. For example, over 2,900 LV sensors-which were strategically installed
at customer locations with the lowest estimated voltage during
peak conditions-provided unique insight into the magnitude
of the change in customer voltage during a targeted 5% voltage
reduction. a comparison of the LV sensor measurements before
and during the level 2 activation is provided in Figure 6.

Sensor Number
Pre-Emergency Mode 2
Pre-Emergency Mode 2 Average
During Emergency Mode 2
During Emergency Mode 2 Average

figure 6. A customer voltage scatter plot comparison.

a primary dependency of peak demand reduction is the
magnitude of the potential voltage reduction. It is also something that can be significantly influenced by a utility because
it is a factor of the distribution circuit design and permissible
customer voltage limits. DEP recognized, based on its preDSDr design standard, that it would need to "condition" all
of its circuits to enable the possibility of such a desired voltage reduction without violating customer voltage. through
analysis and comparison against the current state of its grid,
DEP determined a minimum of 122 V was necessary along
the MV network during peak. this new design standard was
an increase of 3 V over the previous MV objective and essentially narrowed the corresponding voltage profile to 2 V.
the corresponding circuit conditioning initiative of the DSDr
project-which included circuit analysis, quality assurance,
material coordination, and resource management-spanned
over six years and involved the following:
✔ 2,541 new line voltage regulators
✔ 611 new line capacitor banks
✔ 1,539 new MV sensors
✔ 5,444 line phase changes to help improve load balancing
✔ 204 mi of new overhead conductor
✔ 13,000 LV system upgrades (customer transformers,
secondary conductor, services, etc.).
One recommendation for establishing a similar voltage
design standard is determining a benefit-to-cost ratio analysis, because achieving a higher minimal voltage across an
entire circuit may not be cost-justified for certain branches
or scenarios. an additional item for consideration is the
appropriate default voltage bandcenter setting for line regulators, as it contributes to their required placement and number. Finally, the net impact on distribution losses from the
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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2018