Microgrid Test Bed is located at American Electric Power (AEP) Company’s
Walnut Test Facility, pictured below, and designed to demonstrate the
CERTS Microgrid Concept, which is an advanced approach for enabling the
integration of multiple distributed energy resources (DER) into an
electric utility’s distribution system/power grid.
and basis for this R&D Project are as follows:
- The Consortium
for Electric Reliability Technology Solutions (CERTS) was formed in 1999
to research, develop, and disseminate electric reliability technology
solutions in order to protect and enhance the reliability of the U.S.
electric power system under the emerging competitive electricity market
structure. The founding members include four DOE National Labs (Lawrence
Berkeley National Laboratory (LBNL), Sandia National Laboratory (SNL),
Oak Ridge National Laboratory (ORNL), and Pacific Northwest National
Laboratory (PNNL); NSF’s Power Systems Engineering Research Center; and
the Electric Power Group. Currently, CERTS is conducting public interest
research for the DOE Office of Electricity Delivery and Energy
Reliability and California Energy Commission (CEC) Public Interest
Energy Research program.
- AEP shares a
common vision of the potential for advanced technologies within the
electric power industry, in particular the increasing value of DER, and
has developed a unique research and testing facility, offering
opportunities to test equipment, such as generation, energy storage and
power quality devices at its Dolan Test Facility and Walnut Test
- TECOGEN, Inc.
has a core competence in manufacturing and installing combined heat
& power generation (CHP) equipment at commercial and industrial
sites in the U.S. market.
- Youtility, Inc.
has a core competence in designing and installing distributed power
electronics for inverter-based systems.
- Northern Power
Systems has a core competence of engineering, designing and installing
electric power systems at commercial and industrial sites in the U.S.
- University of
Wisconsin has technical knowledge of electric power systems in their
power engineering program, has investigated, modeled and assessed the
concept of establishing microgrids which would be interconnected to an
electric utility’s distribution system/power grid.
The CERTS Microgrid
Concept is an advanced approach for enabling integration of, in principle,
an unlimited quantity of DER (e.g., distributed generation (DG), energy
storage, etc.) into the electric utility grid. A key feature of a
microgrid, is its ability to separate and isolate itself from the utility
system, during a utility grid disturbance. This is accomplished via
intelligent power electronic interfaces and a single, high-speed, switch
which is used for disconnection from the grid and synchronization to the
grid. During a disturbance, the DER and corresponding loads can
autonomously be separated from the utility’s distribution system,
isolating the microgrid’s load from the disturbance (and thereby
maintaining high level of service) without harming the integrity of the
utility’s electrical system/power grid. Intentional islanding of DER and
loads has the potential to provide a higher level of reliability than that
provided by the distribution system as a whole. Thus, when the utility
grid returns to normal, the microgrid automatically synchronizes and
reconnects itself to the grid, in an equally seamless fashion.
What is unique
about the CERTS Microgrid is that it can provide this technically
challenging functionality without extensive (i.e., expensive) custom
engineering. In addition, the design of the CERTS Microgrid provides a
high level of system reliability and great flexibility in the placement of
DER within the microgrid. The CERTS Microgrid offers these functionalities
at much lower costs than traditional approaches by incorporating
peer-to-peer and plug-and-play concepts for each component within the
concept was driven by two fundamental principles:
systems perspective was necessary for customers, utilities, and
society to capture the full benefits of integrating DER into an energy
- The business
case for accelerating adoption of these advanced concepts will be
driven, primarily, by lowering the first cost and enhancing the value of
Each innovation was
created specifically to lower the cost and improve the reliability of
small-scale DG systems (i.e., installed systems with capacities ranging
from less than 100kW to 1000kW). The goal was to increase and accelerate
realization of the many benefits offered by small-scale DG, such as their
ability to supply waste heat at the point of need or to provide a higher
level of power quality to some but not all loads within a facility. From
an electric utility perspective, the Microgrid Concept is attractive
because it recognizes the reality that the nation’s distribution system is
extensive, aging, and will change over time. The CERTS Microgrid Concept
enables high penetration of DG systems without requiring re-design or
re-engineering of the utility’s distribution system.
applications of the CERTS Microgrid include industrial parks, commercial
and institutional campuses, situations that require uninterrupted power
supplies and high power quality, CHP systems, greenfield communities, and
remote applications. In short, wherever economic and DG co-location
considerations indicate the need for multiple DG units within a (or among)
site, the CERTS Microgrid offers the potential for a much more reliable,
flexible, and lower cost solution compared to traditional engineering
approaches for integrating DG.
Team Participants &
Collectively, Team participants agreed to:
1) establish a multi-source inverter based Microgrid Test Bed
interconnected to an electric utility’s typical distribution
circuit/system; and 2) perform various mutually agreed tests of the
Microgrid Concept control scheme to demonstrate functionality and
compatibility with the operation of a typical distribution circuit/system.
responsibilities which include key elements for development, successful
testing and deployment of CERTS Microgrids in the U.S. follow:
- CERTS – The LBNL coordinated
research, contracted and funded activities for the CERTS Microgrid Test
- SNL – The SNL coordinated and
managed the integration of multiple supplier activities, associated with
the establishment and implementation of test programs developed for the
CERTS Microgrid Test Bed.
- TECOGEN Inc. – TECOGEN provided
three separate and complete Gen-set packages for the CERTS Microgrid
Test Bed. Each Gen-set package includes an engine, generator, and a
separate three-phase inverter, developed by Youtility, Inc. The
inverters provide both the CERTS Microgrid control requirements and the
TECOGEN engine management requirements. The inverters have undergone
factory testing to exercise the CERTS control algorithms, prior to
shipping inverters to TECOGEN’s plant; and each generation package has
undergone a complete factory acceptance test at TECOGEN’s plant to
ensure proper design and operation of the total integrated package
(i.e., engine, inverter and associated controls).
Tecogen.com & Youtilityinc.com
- Northern Power Systems – NPS
provided engineering, design details and wiring prints of the complete
Microgrid Test Bed; switchgear cabinets; a static switch; sensing
equipment for data logging, protection and energy management systems;
protection equipment; data logging equipment; plus motor load and
test/fault load equipment. This equipment was installed in cabinets for
outdoor use and factory tested at NPS plant facility. In addition, the
static switch, developed by S&C Electric Company, included the CERTS
Microgrid controls requirements and NPS included this switch in their
factory acceptance test plan.
- After successful
factory acceptance testing, the switchgear, equipment, associated
controllers, and cabinets were packaged and shipped for installation at
AEP’s Walnut Test Site in Groveport, Ohio. In addition, NPS developed
and provided the initial commissioning test plan, as well as the initial
CERTS Microgrid Test Plan, which was provided to Team Participants for
input and revision.
- University of Wisconsin – The
University of Wisconsin provided technical direction and expertise
associated with the algorithms developed for the CERTS Microgrid Test
Bed Project. These algorithms promote a systems approach which views DER
and associated customer load as a subsystem or a Microgrid. In concept,
during disturbances on an electric utility’s distribution system/power
grid, the DER and corresponding customer load can be separated and
isolated (i.e., islanded) from the distribution grid without harming the
integrity of the electrical system and providing a higher level of
reliability to the customer.
- AEP – The Walnut Test Facility
was selected and utilized to accommodate the CERTS Microgrid Test Bed.
AEP made provisions at the site to accommodate the three Gen-sets from
TECOGEN which were received and installed in a Gen-set Enclosure,
provided by AEP to protect equipment from weather related conditions. In
addition, AEP provided the engine’s cooling, exhaust, and air
ventilation systems in the enclosure for the three Gen-sets; power and
auxiliary power transformers; power and control cables in conduit; and
connected equipment according to the wiring prints provided by NPS.
During construction of the Test Bed, AEP received and installed
switchgear, equipment, associated controllers, and cabinets from NPS.
Following construction, AEP provided technical and utility expertise in
the assessment of site commissioning tests, as well as the development
of the CERTS Microgrid Test Plan.
CERTS Microgrid Test Bed Overview
An electrical 1-line diagram (in PDF format) of the CERTS Microgrid
Test Bed follows.
Picture below shows
the south exterior view of Gen-set Enclosure with three 112.5kVA inverter
transformers which connect each Gen-set/inverter, within the Enclosure, to
the Microgrid Test Bed. The electrical panels, attached to the exterior
wall of the Enclosure, include the load side breaker and visible
disconnect switch for each Gen-set. In addition, the electrical breaker
panel and 45kVA transformer on the right provides auxiliary power to
equipment inside the Gen-set Enclosure and Gen-set coolant system.
Picture below shows
the north exterior view of the Gen-set Enclosure with one engine coolant
system, connected to each of the three Gen-set engines within the
Enclosure. Three engine exhausts and sound suppressors are mounted on the
roof with three ventilation exhaust fans mounted on the wall of the
Enclosure. In addition, the main natural gas supply is shown with gas
pressure regulated from one 250 psi source down to three individual 10psi
sources, which are connected to each Gen-set.
Picture below shows
a portion of the interior of the Gen-set Enclosure with one of the
two-door Gen-set/inverter cabinets on the right with the engine and
generator located on the back-side of this cabinet. A DC/DC surge module
is connected to each Gen-set and for this unit is mounted on the lower
left wall. In addition, this picture shows the engine coolant expansion
tank, mounted on the upper wall.
CERTS Team Data Links
The following is a password protected data link to allow CERTS Team
members to review and/retrieve protected and selectable test data.