Table 3. Dc Input Fuse Re-Combiner Options: Power Xpert Solar 1500/1670 Kw Inverter - Eaton Power Xpert Solar 1500 User Manua

Power Xpert Solar 1500/1670 kW Inverter

Table 3. DC Input Fuse Re-Combiner Options: Power Xpert Solar 1500/1670 kW Inverter

Number of Inputs
Recommendations
(24 maximum)
24 x 1000 Vdc Fuse
22 x 1000 Vdc Fuse
20 x 1000 Vdc Fuse
18 x 1000 Vdc Fuse
16 x 1000 Vdc Fuse
14 x 1000 Vdc Fuse
Other, larger fuses
Note
1
Consult Eaton.
Grounded Input Circuits
The grounded PV conductors are connected to a non-fused
bus, working in concert with the UL
5-ampere photovoltaic ground-fault detection and
interruption feature. The grounded-conductor connections
require the same 2-hole 1/2-inch diameter (bolt) compression
lugs as the non-grounded conductors, as the examples listed
in Table 3. Up to 600 kcmil single-conductor lugs are
acceptable as listed in Table 3. Consult Eaton for conductors
larger than 600 kcmil or dual-conductor (per terminal) usage.
DC Equipment Ground Circuits and Grounding
Electrode Terminal
A corresponding 1/4-inch thick equipment-ground busbar
to the PV non-grounded and grounded input circuits has
24 single-holes for 5/16-inch single-hole compression lugs.
Additionally, the ground busbar has two 2-hole 1/2-inch dia.
at 1.75-inch spacing, two 1/2-inch, four 3/8-inch spaced at
1.25-inch, and an additional two 1/2-inch diameter holes
for single-hole compression lugs. Use this DC ground bus
as the PV's GET. Refer to Figure 24 for details.
Negative or Positive Grounded Photovoltaic Systems
Either a negative or positive grounded configuration can
be ordered. Either must be ordered and factory-built and
cannot be field modified. Figure 5 displays the typical
negative-grounded photovoltaic system in which the PV
positive is non-grounded.
DC Surge Suppression
Surge suppression devices are featured on both the
grounded (negative) and non-grounded (positive) input bus.
The suppression's primary operation is protecting the
inverter from voltage-spikes from the PV system (modules,
racking, conduit, etc.) principally due to lightning strikes.
Eaton recommends primary lightning-suppression at the
solar field level, in the source-combiners, for all locations
subject to thunder storms and lightning.
10 Power Xpert Solar 1500/1670 kW Inverter MN141001EN—October 2014 www.eaton.com
Fuse Ampacity Compression Lug
Typical Usage 2-Hole: 1/2 inch dia. at 1.75 inch spacing
(DC Amperes) Lugs not supplied with the inverter
160, 200, 250 As specific to solar site or design:
200, 250, 315 350 kcmil example lugs
250, 315, 350
315, 350, 355
600 kcmil example lugs
315, 350, 355
315, 350, 355
400–630 Amp 1
® 1741 compliant
Burndy p/n YA31A3
Ilsco p/n 21ACL-350
Burndy p/n YA36A3
Ilsco p/n 21ACL-600
Inverter DC Disconnect Switches and Pre-Charge
Post the sub-combiner; 3 load-break switches isolate the
inverter stacks from the photovoltaic input circuits. These
disconnect both the positive and negative PV bus.
Prior to the initial manual-closing of the DC switches DS1,
DS2, DS3, the inverter uses a DC-input pre-charge process.
The pre-charge circuit controls the in-rush current from the
PV array ensuring the inverter's capacitive-bank is not
stressed (soft-start effect). From the HMI, the
charge-request is initiated, where the pre-charge circuit is
used to charge to inverter's DC bus capacitors. Once the
input voltage exceeds the configurable wake-up set-point
(voltage), the bus disconnects (DS1, DS2, and DS3) are to be
manually closed. With the disconnects closed, the power
stacks are fully connected to the PV array, ready to invert and
export the photovoltaic DC energy. The pre-charge feature
only needs to be performed when the disconnects are open.
DS1, DS2, DS3 and pre-charge are illustrated in Figure 5.
Once the inverter is commissioned and operational on a
daily-basis, the pre-charge circuit is not used and the daily PV
array energy completes the input capacitor charging in a
natural soft-start effect with increasing solar irradiance.
In the event of a power stack fault, these DC disconnect
switches can be individually opened (tripped), enabling
continuous operation up to 2/3 rated power. In such an
event, the disconnected power stack will also be isolated
from the AC via its corresponding output contactor (K8, K9,
or K10).
Compression Lugs
—
Tin-Plated-Bar: 1/4 inch
Al/Cu
1