Grounding, Bypass Diodes, Maintenance | Kyocera KD140SX-UPU specs

Figure 5. Installation Example of Cable Clamp

NOTE: MAXIMUM SYSTEM VOLTAGE 600VDC.

KD series modules and most PV system components have a maximum system voltage rating of 600 volts DC. Some grid-tie systems operate at or near this voltage rating. Like other polycrystalline solar modules, the open circuit voltage of the KD series module increases as the ambient temperature decreases. Maximum System voltage is computed as the sum of the open-circuit voltage of the series-connected PV modules for the lowest expected ambient temperature. Refer to the National Electrical Code Article 690-7(a) for determining the maximum number of KD series modules that can be placed in series. Temperature coefficients, specific to the module of use, can be used to provide the most accurate prediction of module voltage under temperature extremes.

NOTE: Install the maximum number of series connection for the KD series PV modules so that the system voltage is less than 600V. NOTE: In normal conditions, PV modules may produce bigger current and/or voltage than reported in the standard test conditions. Therefore, when voltage evaluations for components, capacity of conductors, size of fuses, and size of control systems connected to the module output are determined, multiply the values of short- circuit current (Isc) and open-circuit voltage (Voc) that are marked in KD series modules by the factor of 1.25. Refer to Section 690-8 of the National Electrical Code for an additional multiplying factor of 1.25 which may also be applicable.

9. GROUNDING

Before installation, contact the local code authorities to determine the necessary grounding requirements. Attach all PV module frames to an earth ground in accordance with the National Electric Code (NEC)

Article 250. Proper grounding is achieved by connecting PV module frames and all metallic structural members contiguously to one another using a suitable grounding conductor. The grounding conductor shall be of copper, copper alloy or another material suitable for use as an electrical conductor per NEC. The grounding conductor must then make a connection to earth using a suitable earth grounding electrode. Ensure positive electrical contact through the anodizing on PV module frame extrusion by utilizing one of the following methods. Attach the grounding conductor:

(1)to one of the 9mm (0.35”) diameter holes marked “ground” using 5/16” stainless steel hardware. Wrap conductor around bolt. Tighten the screws with adequate torque (usually 132 in-lb). Avoid direct contact of copper ground conductor to aluminum frame.

(2)to a ground lug (manufacture : ILSCO, model : GBL-4DBT). Tighten the screws with adequate torque (usually 62 in-lb). Use #10-32 stainless steel hardware to attach the lug to the module frame by the torque of 40 in-lb. A stainless steel star washer,

positioned between the lug and the anodized surface of the frame, must be employed to break through the anodized layer of the frame extrusion and electrically connect the ground lug to the conducting aluminum frame material.

As a general rule, avoid direct contact of copper or copper alloyed ground conductors with the aluminum module frame.

All ground bond securing hardware in contact with either the aluminum module frame and/ or copper or copper alloy ground conductors must be stainless steel.

11. BYPASS DIODES

Partial shading of an individual module in a source circuit string (i.e. two or more modules connected in series) can cause a reverse voltage across the shaded cells within the module. Module output current is then forced through the shaded area by the remaining illuminated cells and other PV modules in series with the partially shaded module(s). The current forced through the shaded cells within PV module (or modules) causes additional module heating and severe loss of power. The purpose of bypass diodes is to provide a low-resistance current path around the shaded cells, thereby minimizing PV module heating and array current losses.

PV modules employ bypass diodes that have:

・Rated Average Forward Current [IF(AV)] Above maximum system current at highest PV module operating temperature.

・Rated Repetitive Peak Reverse Voltage [VRRM] Above maximum system voltage at lowest PV module operating temperature.

12. MAINTENANCE

Kyocera PV modules are designed for long life and require very little maintenance. Under most weather conditions, normal rainfall is sufficient to keep the module glass surface clean. If dirt build-up becomes excessive, clean the glass surface only with a soft cloth using mild detergent and water. USE CAUTION WHEN CLEANING THE BACK SURFACE OF PV MODULE TO AVOID PENETRATING THE BACK SHEET. PV modules that are mounted flat (0°tilt angle) should be cleaned more often, as they will not "self clean" as effectively as modules mounted at a 15°tilt or greater. Once a year, check the tightness of terminal screws and the general condition of the wiring. Also, check to be sure that mounting hardware is tight. Loose connections may result in a damaged PV module or array.

13. SPECIFICATIONS

Under certain conditions, a photovoltaic module may produce more voltage and current than reported at Standard Test Conditions (STC). Refer to Section 690 of the National Electrical Code for guidance in series string sizing and choosing overcurrent protection.

Table.2 Kyocera KD Series Module Specification

Electrical Characteristics : @ STC

Model Type	KD135SX-UPU	KD140SX-UPU

Rated Power, Watts (Pmax) (W)	135 ±5%	140 ±5%

Open Circuit Voltage (Voc) (V)	22.1	22.1

Short Circuit Current (Isc) (A)	8.37	8.68

Voltage at Load (Vpm) (V)	17.7	17.7

Current at Load (Ipm) (A)	7.63	7.91

Maximum System Voltage	600	600

Recommended maximum number of PV	21	21
modules connected in series	21	21
modules connected in series
Factory installed Bypass Diode (Qty)	8	8

Series Fuse Rating (A)	15	15

Thermal Characteristics :
Temp. Coefficient of Voc (V / ℃)	-0.80x10-1	-0.80x10-1

Nut

Spring washer

Flat washer

Ground conductor

Cup washer

Star washer

Aluminum frame

Flat washer Bolt

Nut

Spring washer Ground lug Star washer Aluminum

frame Flat washer

Bolt

Temp. Coefficient of Isc (A / ℃)	5.02x10-3	5.21x10-3
Temp. Coefficient of Vpm (V / ℃)	-9.20x10-2	-9.22x10-2
Physical Characteristics :
Length, Inches (mm)	59.1 (1500)
Width, Inches (mm)	26.3 (668)
Depth (frame), Inches (mm)		1.81 (46)
Depth (including j-box), Inches (mm)		-
Weight Pounds (kg)	27.6 (12.5)
Mounting Hole Diameter, Inches (mm)	0.35 (9) Qty-4pcs

Grounding Hole Diameter, Inches (mm)	0.35 (9) Qty-4pcs

Figure 6. Installation Example of Grounding

10. BLOCKING DIODES

In systems utilizing a battery, blocking diodes are typically placed between the battery and PV module output to prevent battery from discharging at night. Kyocera PV modules are made of polycrystalline cells with high electrical “back flow” resistance to nighttime battery discharging. As a result, Kyocera PV modules do not contain a blocking diode when shipped from the factory. Most PV charge regulators and inverter incorporate nighttime disconnect feature, however.

Application Class

Class A

NOTES

(1)Standard Test Conditions of irradiance of 1000 W/m2, spectrum of air mass 1.5, and cell temperature of 25 deg C.

(2)See module drawing for mounting and grounding hole locations.

(3)Tolerance of Voc and Isc is +/-10%.