CE+T America Stabiliti 30C3 750/480 User manual

www.cet-america.com
Stabiliti
TM
–Microgrid Operation
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Leading Conversion and Storage Technology for Energy Saving and Power Resilience

Disclaimer
This document is provided “as is” and CE+T America makes no representations warranties, expressed or
implied, with respect to the information contained herein. CE+T America has made reasonable efforts to
ensure the accuracy of information herein and at the time of publication. However, information is
constantly evolving and CE+T America does not purport the information provided is correct,
comprehensive, or exhaustive. This document is for informational purposes only. You should not act upon
information without consulting CE+T America or its authorized distributors.
© Copyright 2020, CE+T America. All rights reserved. No parts of this document may be reproduced in any
form without the express written permission of CE+T America. CE+T America logo are trademarks of CE+T
America. All other trademarks and service marks belong to their respective owners.

Contents
1. About This Document ...........................................................................................................................5
2. Glossary of Terms..................................................................................................................................6
3. Important Safety Instructions...............................................................................................................7
4. Overview...............................................................................................................................................9
5. System Rating........................................................................................................................................9
6. Reference Document ............................................................................................................................9
6.1. MAN - 00115 –Stabiliti Series 30 KW –Installation and Operation Manual –V1.0.....................9
6.2. MAN - 00114 –Stabiliti Series 30 KW –Quick Start Guide –V1.0................................................9
6.3. DOC - 00063 –App Note –Single Wire Microgrid Guide..............................................................9
6.4. DOC –000xx –App Note –Islanding Switchgear Guide ...............................................................9
6.5. DOC –503 –App Note –Rapid Backup Power Solution Guide.....................................................9
6.6. DOC - 00033 –App Note –Transformer & Interconnection.........................................................9
7. Microgrid Operation –Synchronous Vs Asynchronous ........................................................................9
8. Microgrid Operation ...........................................................................................................................10
9. Microgrid Operation –SEL Method ....................................................................................................12
10. Microgrid Operation –Single Wire Command Method..................................................................14
11. Microgrid Operation –Modbus Command Method.......................................................................16

Table of Figures:
Figure 1 - Microgrid Operation - Three Ways .............................................................................................10
Figure 2 - Pros and Cons of Different Microgrid Operation Methods ........................................................11
Figure 3 - Microgrid Operation - SEL Method.............................................................................................12
Figure 4 - Microgrid Operation - Single Wire Method................................................................................14
Figure 5 - Microgrid Operation - Modbus Method.....................................................................................16

1. About This Document
This document is CE+T America proprietary. It is a customer facing document aimed to serve as an
operational guide for Stabiliti converter’s microgrid operation.
Document Revision History:
Contact Information
CE+T America, Austin, Texas
[email protected]om
Date
Revision
Notes
Sept 15th, 2021
A
Initial draft

2. Glossary of Terms
Acronym of Term
Full Expression
AWG
American wire gauge
CEC
California Energy Commission
GFDI
Ground fault detection current
IMI
Isolation monitor interrupter
BESS
Battery energy storage system, specifically e-ON’s. Based on context in the
manual, BESS may refer to complete system including eON batteries and PCS.
PCS
Power conversion system, specially Stabiliti 30C3
PV
Photovoltaic
LCD
Liquid Crystal Display
RSS
Rapid shutdown system
RSE
Rapid shutdown equipment
BoS
Balance of system components
BAMS
Battery array management system
MBMS
Master battery management system
CAN
Communication protocol
Modbus
Communication protocol
SoC
State of charge of batteries, specified in percentage.
UPS
Uninterrupted power supply
HMI
Human machine interface, touch screen or web interface
PPE
Personal Protective Equipment
CCS
Customer Control System

3. Important Safety Instructions
The following safety symbols are used in this manual:
Danger –Procedure or situations that require action to prevent personal injury/death or damage
to equipment/environment.
Warning –Indicates a potentially hazardous situation that, if not avoided, can result in serious
injury or death.
Important Information: Includes key information for the operation of this equipment or specific
instructions to maintain the warranty.
Personal Protective Equipment: This symbol means that use of personal protective equipment is
highly recommended. This includes insulated gloves, steel toed boots, hard hat, reflective fire-
resistant vests, and protective eye goggles.
Note that the equipment must be handled, installed, and operated by qualified engineer/technician with
proper training on handling high/medium voltage electrical equipment. Local and national electrical code
must be used during installation and operations. Failure to observe safety standards could result in
personal injury or damage to equipment/environment.
Danger - All instructions regarding the configuration of this device must be followed. Failure to follow
may result in injury, death, or damage to equipment.
Danger - To avoid an electric shock, verify that the Converter’s external AC and DC Disconnects are open
(off). A minimum wait time of five (5) minutes is required after opening AC and DC Disconnects to assure
that the Converter’s internal capacitors have discharged to zero voltage before performing any work on
the Converter. Utilize lockout procedures to ensure that both AC and DC Disconnects remain in the off
position during all service periods.
Danger –The enclosure contains exposed high voltage conductors. The enclosure front access door must
remain closed, except during installation, commissioning, or maintenance by trained service personnel.
Do not remove the front doors if extreme moisture is present (rain, snow, or heavy dew).
Danger –To avoid an electric shock, verify that the Converter’s external AC and DC Disconnects are open
(off). A minimum wait time of five (5) minutes is required after opening AC and DC Disconnects to assure
that the Converter’s internal capacitors have discharged to zero voltage before performing any work on
the Converter. Utilize lockout procedures to ensure that both AC and DC Disconnects remain in the off
position during all service periods.
Warning –These instructions DO NOT contain any information on the operation of battery systems
outside of this product. Refer the manufacturer for the battery system for installation and servicing
instructions.
Danger –Ensure that the equipment is adequately installed and grounded per NFPA and all applicable
NEC codes.

Danger –Do not leave foreign objects in the enclosure. Keep the area around the enclosure clear of
trash, debris, and other combustible materials.
Warning –Personnel Qualification: Inspections and operations requiring access to lethal AC or DC
voltages, should only be performed by qualified personnel.
Warning –All field wiring must conform to the codes set forth in the National Electric Code ANSI/NFPA
70.
Warning –Replace damaged warning and precautionary labels.
Refer to “Reference Documents” section of this manual for details on manuals/documents that should
be read first before proceeding.

4. Overview
This document serves as a quick start guide to Stabiliti ’s microgrid operation. There are different ways
Stabiliti s can be commanded to form grid (i.e., microgrid operation) and this guide will cover all different
methods and their pros and cons. This document is aimed at providing a “bird’s eye view” only for all
different microgrid operation method. Refer to applicable detailed app notes for further details.
5. System Rating
Note that the max number of Stabiliti that can be used to form microgrid is 8 (240 kw total as one Stabiliti
is 30 kw). There is no minimum limit though. Microgrid function can be achieved via a single Stabiliti as
well.
6. Reference Document
6.1. MAN - 00115 –Stabiliti Series 30 KW –Installation and Operation Manual –V1.0
6.2. MAN - 00114 –Stabiliti Series 30 KW –Quick Start Guide –V1.0
6.3. DOC - 00063 –App Note –Single Wire Microgrid Guide
6.4. DOC –000xx –App Note –Islanding Switchgear Guide
6.5. DOC –503 –App Note –Rapid Backup Power Solution Guide
6.6. DOC - 00033 –App Note –Transformer & Interconnection
Also refer to PCS’ modbus map for details.
7. Microgrid Operation –Synchronous Vs Asynchronous
In essence, microgrid operation means that the Stabiliti will form grid and keep the loads running even
when the grid is lost. For Stabiliti to be able to do so, there are specific software settings and specific ways
to set the whole system up from wiring standpoint. The exact settings depend on desired microgrid
operation. Before we go into further details, its important to understand the difference between
synchronous and asynchronous microgrid function.
Synchronous means that upon receipt of appropriate commands (and grid conditions), ALL Stabiliti s in
the system will start forming (or following) the grid at the exact same time. Such operation is required
when the load that needs to be powered up is exactly equal to the size of Stabiliti installation. To achieve
this, a use of islanding switchgear or following “single wire microgrid” method is crucial. This of course
adds cost and adds some complexity to the overall control.

If the load that is supposed to be protected is controllable, meaning it can be gradually brought online
then an asynchronous way of controlling microgrid is a cheaper alternative. In asynchronous mode,
individual Stabiliti are brought online one by one. They may all receive “microgrid command” at the same
time but there might be a slight delay for individual units to start forming microgrid. Due to this limitation,
this method is ideally suited for completely off grid applications.
8. Microgrid Operation
There are three different ways of achieving microgrid operation. Each one has their own pros and cons.
Note that there is a max limit of 8 converters while forming microgrid. Refer to the table below for details:
Figure 1 - Microgrid Operation - Three Ways

Refer to the section below to gain better understanding of each term used in the table above.
Definitions:
•On grid means system is normally connected to grid. But when grid is lost, the Stabiliti system is
required to form microgrid to support the loads.
•Off grid means the system has no connection to the grid at all and there will never be an actual
grid connection.
•Black start refers to a mode of operation where the load is required to be brought online from a
completely offline state.
Here is a summary of pros and cons of all three methods:
Figure 2 - Pros and Cons of Different Microgrid Operation Methods

9. Microgrid Operation –SEL Method
This is how the system shall be interconnected when using CE+ T supplied islanding switchgear:
Figure 3 - Microgrid Operation - SEL Method
Field Wiring:
The AC connection from Stabiliti will go into an AC distribution panel (not shown above) and then into
“Islanding Switchgear”. From there, it will connect to the grid. Note that the “power supply and digital
control signals will go from “Islanding switchgear” to one Stabiliti and then connection to subsequent
Stabiliti will be daisy chained from this Stabiliti. Note that the “Islanding Switchgear” design may look
different (look and feel) than the one shown in figure above. The field connections and functionality will
remain the same. This is the most recommended mode of operation for all “on grid” applications.
System Startup –Initial Start of System:
The system must be set up when the grid is present. Upon interconnecting everything, the SEL relay will
engage 24 volts to the two digital signals connected to Stabiliti and at the same time it will energize/close
the Grid Interconnect Contactor (GIC). At this time the load is powered via the grid. Now each stabiliti
should be manually commissioned and brought online. Note that Stabiliti’s AC port must be set in “FPWR”
mode. When grid is present and SEL relay is not commanding the Stabiliti to form the grid, Stabiliti will
wait for a Customer Control System (CCS) to send a power command to support the load.

Follow to Form Operation –Loss of Grid:
When the grid is lost, the SEL relay detects the loss of grid and notifies the Stabiliti to start getting ready
to form the microgrid. After this, SEL relay opens the GIC. Upon successful GIC operation, SEL reports back
to Stabiliti that its ok to form microgrid now. This whole process takes around 100 ms. Note that once
Stabiliti are forming the grid, they will ignore power command sent by CCS and will keep the loads on by
appropriately taking power from the two DC ports.
The Stabiliti’s on board control systems are normally powered via the 480-vac connection. During the
“following to forming” transition, the UPS within the Islanding switchgear provides power to keep the
internal Stabiliti controls running.
Form to Follow Operation –Grid is Back:
When the grid is back, SEL ensures that the grid formed by Stabiliti is in sync (phase, voltage, frequency)
with the grid and upon successful sync, SEL relay closes the GIC and releases both microgrid command
signals from Stabiliti. This transition is almost seamless.
Application:
Using this method adds cost to the system but it greatly automates the microgrid function. A customer
control system will have to make no decision to enable any of “forming to follow” or “follow to forming”
transitions. This is best suited for all “on grid” applications.
Refer to “DOC –000xx –App Note –Islanding Switchgear Guide” for additional details.

10. Microgrid Operation –Single Wire Command Method
This is how the system shall be interconnected when using “Single Wire Method”:
Figure 4 - Microgrid Operation - Single Wire Method
Field Wiring:
The “power supply and digital control signals will go from “Islanding Assist Box” to one Stabiliti and then
connection to subsequent Stabiliti will be daisy chained from this Stabiliti. CCS must control both the
“Islanding Assist Box” and the GIC to achieve the same operation as performed by CE+T supplied Islanding
Switchgear (as described in the previous section). It is customer’s responsibility to design appropriate
wiring and control algorithm to achieve the same. The figure above serves as a guide to achieve required
field wiring.
Note: Regarding the “Islanding Assist Box”, CE+T can provide design documentation but will not be able
to have one built for the customer. It will be customer’s responsibility to build one as per provided
documentation. It is also customer responsibility to design the CCS to control the “Islanding Assist Box”.
Refer to “DOC –503 –App Note –Rapid Backup Power Solution Guide” for additional details.

System Startup –Initial Start of System:
The system must be set up when the grid is present. Upon interconnecting everything, the CCS shall
engage 24 volts to the one digital signal connected to Stabiliti and at the same time it shall energize/close
the Grid Interconnect Contactor (GIC). At this time the load is powered via the grid. Now each stabiliti
should be manually commissioned and brought online. Note that Stabiliti’s AC port must be set in “FPWR”
mode. When grid is present and CCS is not commanding the Stabiliti to form the grid, Stabiliti will wait for
CCS to send a power command to support the load.
Follow to Form Operation –Loss of Grid:
When the grid is lost, the CCS must detect the loss of grid and before commanding the Stabiliti to form
microgrid, it must ensure the system is isolated from the grid by opening up GIC. Upon successful GIC
operation, it must command Stabiliti to form microgrid. Note that if CCS is not fast enough to make these
decisions, the load may be dropped, and additional coordination will be required to black start the loads.
This will be solely customer’s responsibility to ensure reliable Stabiliti operation.
The Stabiliti’s on board control systems are normally powered via the 480-vac connection. During the
“following to forming” transition, the UPS within the Islanding switchgear provides power to keep the
internal Stabiliti controls running.
Form to Follow Operation –Grid is Back:
When the grid is back, CCS must ensure that the grid formed by Stabiliti is in sync (phase, voltage,
frequency) with the grid and upon successful sync, CCS can close the GIC and release the microgrid
command signal from Stabiliti. Again, this will be solely customer’s responsibility to ensure reliable Stabiliti
operation
Application:
This method is best suited for customers who do not wish to use CE+T provided islanding switchgear.
While this method saves upfront cost (no cost added for Islanding Switchgear) it adds significant amount
of work for the customer to build the ““Islanding Assist Box” and also make changes to CCS to control
“Islanding Assist Box” and GIC.
Disclaimer:
Note that in this case, the full operation is solely controlled by “Customer Control System”. CE+T shall not
be held liable for damage or harm caused to equipment or personnel due to incorrect system operation.
Refer to “DOC –00063 –App Note –Single Wire Microgrid Guide” for additional details.

11. Microgrid Operation –Modbus Command Method
This is how the system shall be interconnected when using “Modbus Method”:
Figure 5 - Microgrid Operation - Modbus Method
Field Wiring:
The UPS box must be connected to 24 volts dc power supply pins within Stabiliti. Apart from this, there is
no additional/special field wiring.
Note: Regarding the “UPS Box”, CE+T can provide design documentation but will not be able to have one
built for the customer. It will be customer’s responsibility to build one as per provided documentation.
System Startup –Initial Start of System:
Before reaching the project site, the UPS box must be fully charged. Ensure the load is physically
disconnected from the Stabiliti system. Use the “UPS box” to power up Stabiliti. Once Stabiliti is on, the
AC port must be set to “FPWR”. Once set, start Stabilitis one by one. Once all the Stabilitis are on, ensure
they are all reporting “Forming” status on the LCD panel. Once this is confirmed, then provided there is

enough PV, storage or DC power sources (connected to Stabiliti’s DC port), the Stabiliti system can now
be connected to the load.
Follow to Form Operation –Loss of Grid:
Not applicable.
Form to Follow Operation –Grid is Back:
Not applicable.
Application:
This method is best suited for projects which are completely off grid.
Disclaimer:
Note that in this case, the full operation is solely controlled by “Customer Control System”. CCS must
control all DERs appropriately to ensure reliable operation. CE+T shall not be held liable for damage or
harm caused to equipment or personnel due to incorrect system operation.

End of Document