Photovoltaic System Performance Indicator
Develop
and demonstrate a system to determine that a residential
utility-interactive PV system is operating properly and that the ac
power output is following the solar power available to the PV array.
Hundreds of thousands of
utility-interactive photovoltaic (PV) power systems have been and are
being installed on dwellings throughout the United States.
Many more such systems have and are being installed on dwellings in
Germany and Japan. While many of these installed systems
have displays on the front of the inverter, many do not, and the
inverters are generally mounted in an out-of-the-way location where they
are not seen on a daily basis. Some inverters have optional or
included wired or wireless displays that can be used to remotely display
the operation of the inverter, but these displays are generally of
interest only to the technically minded individuals. In many
systems without a display or where the display is not used, a reduction
in or cessation of the PV system output would not be noticed in the
monthly utility bill where the normal energy usage patterns vary more
than the energy generated by the PV system. Without a measurement
of the solar intensity on a continuous basis, it is not possible to
determine if the system is operating properly and/or producing the rated
output.
Develop and demonstrate a system to
determine that a residential utility-interactive PV system is operating
properly and that the ac power output is following the solar power
available to the PV array.
The proposed system
should:
-
Measure the solar irradiance/solar power input at the array location
usually on the roof of the dwelling and any other parameter that may
affect array output.
-
Measure the ac power or equivalent parameter being generated by the
PV inverter.
-
Compare the two measurements and, with a suitable constant,
determine if the ac output is sufficiently close to (tracking) the
solar input. Tolerance of tracking shall be adjustable.
-
Provide a “System OK”, “System not OK” or other equivalent indicator
that can be placed anywhere in the dwelling (e.g., on the front of
the refrigerator).
-
Wireless operation between components is preferred.
-
Solar power, utility power or low-power, long-life battery
operation, as appropriate, may be used.
-
All electrical connections shall be in compliance
with the 2008 edition of the
National Electrical Code.
-
Be compatible with inverters rated for maximum power outputs of 700
watts to 7500 watts output operating at either 120 volts or 240
volts, 60 Hz alternating current.
Each team is advised to
read the Participation Guide for a comprehensive understanding of the
contest evaluation criteria. Upon your registration, WERC will
provide you with a copy of the Public Involvement Plan and Participation
Guide. Additionally, your proposed design will be evaluated on
issues identified in the problem statement as well as the following:
-
Simplicity of display/ease of understanding;
-
Effectiveness in dealing with varying PV system designs;
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Cost and reliability;
-
Ease of installation—minimal attachments to the PV/electrical
system;
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Minimal maintenance and continuous operability; and
-
Lack of interference with other household devices
At
the design contest, each team will demonstrate the selected technology
using a PV array/system. The specific details of the PV system
requirements will be provided at later date. Appropriate Material
Safety Data Sheets should be available during the bench scale
demonstration.
During the contest, a typical utility-interactive PV system in a
residential configuration will be set up and operating in an outside
area. The specifications of the PV system will be provided to the
teams in advance. These will include the power and voltage rating
of the inverter. DC PV system parameters and connections
will not be available. Each team will have access to the PV system
including the PV array mounting structure and the inverter ac output
circuits. AC voltage at 120 volts will be available to power
equipment, if needed. The distance between the PV array and the
inverter may vary between 10 and 100 feet.
The
written report is the best means to demonstrate your team’s insight into
the problem. The report should discuss other technologies considered but
not pursued and why and to give the reader full understanding of the
magnitude of your team’s involvement with the problem details. The
report will be evaluated for clarity, logic and coherence.
Standards appropriate for publications in technical journals apply.
In
addition to the listed requirements, the following must be discussed in
your report to WERC management:
-
Schematics of each piece of equipment in the Performance Indicator
System;
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Pictures and descriptions of each component;
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List of parts and specifications, source, and cost of each;
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Calculations and equations used in the system;
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Descriptions of any software;
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Installation instructions including any safety warnings;
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User instructions; and
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Maintenance instructions including any safety warnings.
Contact:
Barbara Valdez, Program
Facilitator
(575) 646-7821
(800) 523-5996
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