IEEE Power & Energy Magazine - May/June 2018 - 83
In an IWSES plant, wind turbines, photovoltaic solar arrays,
and a battery energy storage system are integrated into
a single plant using state-of-the-art controls.
whether underground cables should be used for the collector
system or a mixed-construction approach using both underground cables and overhead conductors would be preferable. designs for both cases were compared to evaluate
For the mixed-construction case, underground cable
was used to feed the PV systems or whenever the conductor path entered a wind turbine exclusion zone. in this case,
riser poles were used to transition between underground and
overhead construction. all underground design was used for
phase 1-a of the project to account for the tight arrangement
of PV arrays and wind turbine exclusion zones, even though
the cost was slightly higher than with the mixed-construction approach. For phases with overhead transmission lines,
the routing was designed such that there was no loss of PV
generation due to shadowing from the lines. to evacuate the
power, a 33-KV/220-KV pooling substation was designed
for each phase of the project. the Bess was sited at the
pooling substation and connected to the low-voltage side of
Design of Controls and Communication System
the final design step was the design of the controls and communications system that enables the Bess to communicate
with the plant's wind turbines and solar arrays and also enables
the sldC and renewable energy Management Center to perform the various applications. the proposed plant control
architecture consists of three control device types:
✔ Plant energy management system: this system orchestrates all control and communication actions and provides the interface to the utility and sldC.
✔ Plant master control station: this station is a hardened
computer that hosts critical real-time control services.
its main function is to compute the set point for the
storage system's power, i.e. the command for the Bess
charging or discharging cycles. it also computes the
plant-level commands for the wind and solar plants.
✔ Plant edge control station: the edge plant-level controllers are hardened industrial controllers located at
the Bess as well as at each wind or solar plant. these
units control the actual power flow at the point of interconnection based on local measurements and commands received from the master-level controller. the
plant edge controllers are typically multifunction controllers that provide the physical interface to the lower
inverter-level controllers and sensors.
Next Steps for the IWSES Project in India
the next step is to develop the 41-Mw iwses plant as a
grant-funded pilot project. the lessons learned from the
demonstration project can be used to develop the technical design, commercial arrangements, and energy storagerelated policies and regulations that will have a strong influence on future energy storage projects in india.
we acknowledge the support provided by the U.s. trade and
development agency (Ustda) and raj Budhavarapu [formerly with the infrastructure leasing & Financial services
(il&Fs) energy development Company, ltd.] in the execution of this study.
For Further Reading
"technical assistance for the integrated wind, solar and energy
storage project," rep. for task 1-10. activity rep. 201531004a,
Ustda (available on request from the Ustda).
M. Brower, Wind Resource Assessment: A Practical
Guide to Developing a Wind Project. Hoboken, nJ: wiley, 2012.
J. Burton and B. sharpe, Wind Energy Handbook, 2nd
ed. Chichester, U.K.: wiley, 2011.
s. t. Frandsen, "turbulence and turbulence-generated
structural loading in wind turbine clusters," risø-r1188(en), risø national laboratory, Jan. 2007.
t. M. letcher, Wind Energy Engineering: A Handbook for
Onshore and Offshore Wind Turbines. new York: academic, 2017.
V. Badescu, ed., Modeling Solar Radiation at the Earth's
Surface: Recent Advances. Berlin, germany: springer-Verlag, 2008.
a. luque and s. Hegedus, eds., Handbook of Photovoltaic Science and Engineering, 2nd ed. Chichester, U.K.: wiley, 2011.
Sundar Venkataraman is with ge energy Consulting,
Chris Ziesler is with aws truepower, a Ul company,
albany, new York.
Peter Johnson is with aws truepower, a Ul company,
albany, new York.
Stephanie Van Kempen is with aws truepower, a Ul
company, albany, new York.
ieee power & energy magazine