MYPV ClearSky Plus User manual

myPV ClearSky™ Plus User Manual 1
myPV ClearSky™ Plus User Manual
V2.3
Welcome
This interactive manual guides new and experienced users through the ClearSky PLUS
modular interconnection with inrush mitigation.
Additional support is available on our website at www.myPV.pro
You may also contact support via phone or email:
Support Line (M-F, 9am-5pm Eastern): 470-387-9011
Support Email: [email protected]
Introduction
Resources
Theory of Operation
Design Considerations
Protection Relay Settings
Receiving
Electrical Terminations
Network Integration
Pre-Energization Checks
Initial Energization
Operational Testing
Commercial Operation
Spare Parts
Torque Schedules
Troubleshooting

Introduction
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Introduction
The myPV ClearSky™ PLUS is an innovative, efficient, and reliable product that
modularizes your interconnection and provides whole-facility inrush current mitigation,
accelerates your readiness for commercial operation, de-risks your commissioning, and
removes barriers to power quality restrictions.
Equipment Build Standards
All myPV ClearSky PLUS equipment is built with quality and reliability as our top priority.
Built to last with heavy 11-gauge powder coated steel, wide temperature industrial-rated
electronics, and fully integrated in a UL 508a controls facility, the product line conforms
to the following standards:
Padmount gear - conforms to applicable ANSI, IEEE, and NEMA standards
Constructed with UL or ETL recognized components
Circuit breaker ETL listed per file 4000068
Bushings & fuses - components rated in padmount gear per UL file E328700
Equipment is suitable for use in NFPA 70, NEC compliant installation
Metering and relay control panels are UL 508a certified and labeled

Introduction
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myPV ClearSky PLUS - 2021 Version
Standard Features
The myPV ClearSky PLUS product line is designed to provide a self-contained and
modularized solution for both distribution and transmission interconnected generation
facilities operating up to 25kV with a maximum continuous current of 600A (per MV
feeder).
Standard Features Include:
Revenue Grade Metering Default configurations include SEL-735 metering with
revenue grade CT and PT instrumentation. Metering make/model and brand may be
modified to alternative hardware to satisfy individual Customer requirements.
(Additional standard options available below)
Protection Relaying & Reclosing All configurations of the myPV ClearSky PLUS
use a SEL-751 with specific I/O and software features to support the three (3)
integrated VFI breakers. The SEL-751 shares PTs with the meter, but has dedicated
protection class CTs for appropriate fault condition monitoring. The SEL-751 may

Introduction
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not be modified, however a reduct relay may be added to satisfy individual
Customer requirements. (Additional standard options available below)
Fully Automated Inrush Current Mitigation All configurations of the myPV
ClearSky PLUS utilize a unique pre-insertion transformer and switching sequence
that limits the facility’s inrush current on initial energization, and allows full current
flow when exporting or importing following energization. The switching sequence is
fully automated, coupled with the protective relaying functions, and able to be
monitored remotely.
myPV IQ™ - Remote Operator Interface All configurations of the myPV ClearSky
PLUS arrive with a cellular modem and browser-based HMI installed. The cellular
modem is enabled with a temporary data plan to support remote access to the
metering and relay devices during initial startup and commissioning activities. The
cellular service can be disabled or re-enabled to suite both security requirements as
well as warranty support issues during the warranty period. Additionally, the myPV
IQ - Remote Operator Interface provides a browser-based dashboard for
commissioning agents and engineers to access metering and relay telemetry as
well as relay event information. Data is available quickly and early without the need
for any special software or skillset. This feature does not interfere with any third-
party monitoring or SCADA and may be disabled (or upgraded) by the Customer at
any time.
Networking Communications All configurations of the myPV ClearSky PLUS are
equipped with an unmanaged 8-Port 10/100BaseT(X) Fast Ethernet switch. All
equipment mentioned above is connected to and IP addressed for networking
communication through this switch by default. (Additional standard options available
below)
Self-Powered & Battery Backed-Up All controls, networking, metering, and
relaying equipment run on a self-contained 24V, 10A power supply that includes
battery backup. In the event of a loss-of-grid, the system remains fully operational to
provide telemetry, trip event information and alarming. Typical battery backup times
exceed 4 hours after the loss of grid power.
IEEE 386 MV Interfaces All configurations of the myPV ClearSky PLUS use
industry standard bushing well and inserts MV interfaces. 200A load-break or 600A
dead break interfaces may be specified at the time of order based on facility
amperage requirements. (Additional standard options available below)

Introduction
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Standard Options
The myPV ClearSky PLUS product line provides standard options to upgrade and add
components in a manner that supports the most frequently requested Customer
requests.
Standard Options Include:
Revenue Grade Metering Upgrades
[DEFAULT] Basic PQ waveform recording (15th harmonic, 16 samples/cycle, 15 cycle
duration)
[UPGRADE] Advanced PQ waveform recording (63rd harmonic, 16/128/256
sample/cycle, 15-600 cycle duration)
Protection Relay Upgrades
[DEFAULT] Directional Current Sensing, Reclosing, and DNP3 Communications are all
included features
[UPGRADE] Arc Flash Sensing w/ highspeed I/O for fast tripping & Integrated fiber optic
arc flash detection
[UPGRADE] Generator-side voltage sensing for MicroGrid Vsync capabilities (Arc Flash
Sensing included)
MV Interface Dual Bushings
[DEFAULT] Three (3) MV Interfaces on the Utility side dead front, and three (3) MV
Interfaces on the Solar side dead front
[OPTION] A total of six (6) MV Interfaces on the Utility side dead front, to allow for loop-
feed or passthrough connections
[OPTION] A total of six (6) MV Interfaces on the Solar side dead front, to allow for loop-
feed or passthrough connections
Equipment Riser
[DEFAULT] Standard integrated 7” riser
[OPTION] *Taller 12” riser (Adds an additional 5” of height for MV cable management)
Control Cabinet

Introduction
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[DEFAULT] Technician visible wire-glass control cabinet door with external LOTO
handle
[OPTION] Privacy solid metal door control cabinet with external LOTO handle
[OPTION] Additional Customer equipment control cabinet with external LOTO handle
(wire-glass or solid door)
Padmount Powder Coat
[DEFAULT] Solar Industry White
[OPTION] Any color you want ... as long as its white ;-)
Network Communications
[Default] Unmanaged 8-Port 10/100BaseT(X) Fast Ethernet switch
[MULTIPLE OPTIONS] Managed switched, MM and SM Fiber, Serial to Fiber options
are all available. Contact us for specifics.
myPV IQ™ - Remote Interface
[DEFAULT] Installed and licensed for monitoring and control of the myPV ClearSky
PLUS’s integrated metering, relaying, and automated switching devices
[OPTION] Upgrade the myPV IQ license to support full facility device (inverters,
trackers, weather stations, other) monitoring and control as the primary SCADA system.
Utility DER Interface
[DEFAULT] Not included
[OPTION] Additional SEL RTAC 3505 installed inside myPV ClearSky PLUS control
cabinet to support facility-to-offtaker RTU communications for generator monitoring and
controls integration
2021 Product Line Modifications
We make every effort to understand, anticipate, and listen to our customers’ needs. The
2021 myPV ClearSky PLUS product line introduces the following modifications when
compared to the prior model year:
Two (2) dual source voltage labels have beed added; one (1) externally on the
LV Termination Cabinet door, one (1) internally on the LV Terminal Block
protective cover

Introduction
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Both Utility side and Solar Side MV Terminations are now deadfront style, MV
separable connections (IEEE 386 Interfaces)
The MV separable connections have been moved vertically to provide a minimum
additional 5” of space for cable management
The MV Termination compartments are nominally 6” deeper (front to back) to allow
for MV elbow stacking and accessories
The LV fused disconnect has been upgraded to a 690V rated 3-pole breaker
The internal VFI 3-phase Ganged breaker has been upgraded to three (3)
independent VFI 1-phase breakers, supporting both local push-button single-phase
testing operations as well as remote SCADA 1-phase trip operations as well
A second wire-glass viewing window has been added (opposite the first) to allow for
improved cabinet internal component inspections from the outside
The control cabinet now has a dedicated chase to allow for network cable routing
via the MV cabinet (no external conduit runs are required)
Metering and Relaying CTs are now clearly labeled for both phase and orientation in
the event they are unmounted during MV cable management
The myPV IQ™ - Remote Interface and integrated cellular modem have been
added to the standard product offering to support remote commissioning and
troubleshooting by Customers, Customer assign Engineering resources, and Solar-
Ops support staff.

Resources
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Resources
The myPV ClearSky™ PLUS is a standardized product, supported by documentation
and resources to ensure your success.
Technical Documents
For the most up to date product drawings, CAD blocks, and application guides visit our
Technical Documents page by registering on our Support Resources page.
MV Separable Connectors
Also referred to as “Elbows”, separable connectors are medium voltage (MV)
components that provide a watertight, fully electrically insulated, electrical termination
for MV conductors on both the Utility and Solar sides of the myPV ClearSky PLUS. All
MV separable connectors support IEEE 386 compliant interfaces.
Although we do not have any preference for brand of manufacture, Eaton and ABB both
have excellent product catalogs that illustrate the breadth of available products, how
they may be used, and available part numbers.
Major Manufacturers Include:
ABB - Elastimold [PDF]
Eaton - Cooper Power Systems [PDF]
3M - Separable Connectors [PDF]

Resources
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The myPV ClearSky™ PLUS product line is available in two (2) frame sizes that are
determined by maximum voltage rating. A standard set of options may be added to any
of the frame sizes to configure the standard product to meet individual Customer
requirements. The standard product specifications are listed below:
myPV ClearSky™ PLUS 2021 - Product Line Representative Cross Section
Product Line Specifications

Resources
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NOTE: Contact us is you have a 35kV application … we can support you, this frame
size is not currently within our standard product line.

Resources
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South - Front Side SE Corner - Front Side / Pre-Insertion
Side
East - Pre-Insertion Side (Doors Open) East - Pre-Insertion Side Transformer
Product Photos
While myPV ClearSky products do vary in size, all product frame sizes are arrange in
the same manner. The following orthographic photos provide a visual reference for
common locations of common features.

Resources
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East - Pre-Insertion Side Potential
Transformers (PTs)
NE Corner - Pre-Insertion Side / Back
Side
West - Terminations Side (Doors Open) NW Corner - Back Side / Terminations
Side

Resources 7
West - Terminations Side Current
Transformers (CTs)
West - Terminations Side LV Cabinet &
Cable Entry
West - Terminations Side LV Cabinet
Network Entry
Front - Doors Open
13

Resources 8
South - Front Side RVC Controller,
Metering & Relay Cabinet
East - Pre-Insertion Side
East - Pre-Insertion Side MV Fuse
HoldersFuses & Silencers Shipped w/
Equipment
East - Pre-Insertion Side Transformer
(Side)
14

Resources
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East - Pre-Insertion Side Transformer MV
VFI Breakers
North - Back Side
West - Terminations Side
West - Terminations Sid MV Cabinet &
Cable Entry

Resources
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West - Terminations Side LV Cabinet West - Terminations Side LV Cabinet
Terminal Blocks (#2 AWG Cu)

Resources
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NW Corner - Terminations Side / Front Side
Frame Size by Voltage Class
myPV ClearSky™ PLUS is available in two (2) frame sizes that are determined by the
facility’s line-to-line voltage rating.
Applications that have interconnection voltages equal to or below 25kV (line-to-line) are
supported.
NOTE: Contact us is you have a 35kV application … we can support you, this frame
size is not currently within our standard product line.
Determine Your Facility’s Voltage Class:

Resources
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Continuous Current Sizing
All myPV ClearSky PLUS frame sizes support a maximum continuous current rating
of 600A.
Determine Your Facility’s Continuous Current Sizing:

Resources
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The myPV ClearSky PLUS has a single set of three (3) revenue grade PTs that are
shared for metering and protection relaying functions.
The myPV ClearSky PLUS has two sets of three (3) CTs however. The first set is
dedicated to review grade metering, while the second set is dedicated to protective
relaying. The revenue grade CTs are specified to provide high accuracy measurements
throughout the high, mid, and low range of expected current flow to ensure proper
power readings. The protection CTs are specified to provide operation on the higher end
of expected current flow to accurately capture (over current) fault events.
NOTE: A fourth CT can be used to directly measure neutral current, however most
meters and relays are capable of accurately calculating neutral current without a
physical CT being installed.
PTs step down the interconnection voltage to a range that the meter’s inputs can accept
… typically a nominal 120V. As an example, the ratio of a PT (e.g. 60:1) will result in a
voltage at the meter of 119.993V for a 12.47kV interconnection.
The Math:
The Interconnection Voltage: 12.47 kV * 1000 = 12,470V L-L
The Line Voltage: 12,470V L-L / sqrt(3) = 7,199.558V L-N
The PT’s Output Voltage: 7,199.558V L-N / 60 = 119.993V
Most meters will accept PT voltages up to 300V or even 600V, so sizing a PT to achieve
120V is more of a rule of thumb that a requirement … ensuring the PT has appropriate
accuracy throughout the range of expected current flow (0 to the Export Limit or your
Facility) is more important.
CTs similarly step down the interconnection current flow to a range that the meter’s
inputs can also accept … typically a nominal 5A. As an example, the ratio of a CT (e.g.
300:5) will result in current at the meter of 5A for 300A of current flow.
Instrument Transformers
Potential Transformers (PTs) and Current Transformers (CTs) are devices used to
measure voltage and current respectively.

Resources
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Line Amperage (3-Phase System): 694.487A / 3 = 231.496A
Now that we know are maximum expected current flow is 232A, we can choose an
appropriate CT ratio.
For metering, we may choose a 300:5. The 232A falls into the mid-range of the 300A
rating, however we could also safely choose a 200:5 so long as the CT has an
appropriate “rating factor” which will typically allow a CT to operate at 1.5 or 2.0 of its
nameplate while still maintaining proper accuracy. To make this determination, the CTs
rating curves should be consulted to ensure the CT rating is appropriate for your
application.
For relaying however, we may choose a higher ratio CT, possibly a 400:5. This higher
ratio will provide better measurements of fault current conditions that are typically much
larger than the system’s normal operating conditions. A 400:5 CT with a rating factor of
2.0 will provide measurements of up to 800A before saturating.
Regardless of what PT or CT ratio is ultimately selected, the meter and protection relay
devices are configured to understand what instruments are connected via the PTR
(Potential Transformer Ratio, 60: 1 = 60) and CTR (Current Transformer Ratio, 300:5 =
60) settings variables.
The selection of instrument transformers is specific to the application, the
interconnection and facility electrical characteristics, and also an Engineer’s preference.
For the myPV ClearSky™ PLUS, we have assembled the following table of standard
part numbers for PTs and CTs to use, unless otherwise specified buy the Customer:
The Interconnection Voltage: 12.47 kV * 1000 = 12,470V L-L
The Line Voltage: 12,470V L-L / sqrt(3) = 7,199.558V L-N
Facility Wattage: (5,000kW * 1000) = 5,000,000W
Facility Total Amperage: 5,000,000W / 7,199.558V L-N = 694.487A
The Math (Expected Current Flow for a 12.47kV Interconnected, 5,000kW Facility):