Photovoltaic Distribution and Combiner Equipment

On opposite sides of the inverter. The combiner box is on the DC side, installed outdoors in the array field, gathering several photovoltaic arrays into one DC output to the inverter, at IP65 in a hot-dip galvanised steel enclosure; the grid-connection cubicle is on the AC side, installed in the distribution room, taking the inverter output through a breaker and metering transformers to the point of connection, at IP30 in a combined-pattern floor-standing line-up. A plant needs both, and the quantities follow the array zoning and the number of inverters.

By project confirmation. The module type and the number in series set the array open-circuit voltage and operating current, and the inverter DC input voltage range sets how many modules one string can carry; only once both are fixed can the combiner box input ways, the fuse rating per way, and the DC breaker and surge arrester ratings be settled. Send the module datasheet, the inverter DC-side parameters and the array zoning drawing and a configuration can be proposed.

The DC side of a photovoltaic array has no natural current zero, and the modules cannot be stopped from generating while the sun is on them, so fault current may return to the array through either pole. The combiner box therefore takes PV-rated fuses on both positive and negative poles on dedicated matched bases, a separate PV-rated circuit breaker on the DC output, and a surge arrester on the output busbar covering positive-to-earth, negative-to-earth and positive-to-negative.

Yes. The monitoring unit reads per-string current, output voltage, box temperature, surge arrester status and breaker status and sends them over the communication interface; the device address and device number are set on the equipment itself and the OLED display shows current, voltage, power and temperature on the spot. The protocol, signal list and polling interval are aligned with the plant monitoring system during the technical agreement.

The combiner box enclosure is hot-dip galvanised steel plate at IP65, and the stated performance covers waterproof, dustproof, rustproof and salt-spray resistant duty for outdoor installation. Please state the corrosion category, irradiation and temperature conditions of the specific site when enquiring, so the enclosure surface treatment and the self-powered range of the monitoring unit can be confirmed.

Not within the scope of this page. What this page supplies is the distribution equipment on either side of the inverter — the combiner box on the DC side and the grid-connection cubicle on the AC side; the inverter is procured separately by the project according to capacity and grid-connection requirements. It is drawn into the chain to show where these two pieces of equipment sit and what they interface with.

Yes. The grid-connection cubicle is supplied as equipment, while the enclosure, panel arrangement, auxiliary systems and interface integration needed by a photovoltaic inverter step-up station or a renewable grid-connection prefabricated substation come from the prefabricated power module line, with the cubicle delivered as equipment inside the module. Combiner boxes in the array field are installed position by position and ship with the equipment.

Four things at minimum: the installed capacity and array zoning; the module type and the number in series; the inverter DC input range and AC output parameters; and the voltage level and metering requirement at the point of connection. To quote to contract level, add the combiner box mounting positions and cable entry arrangement, the communication protocol of the monitoring system, the corrosion and temperature conditions on site, and the destination market standards and document list.