AC Combiner Box – reliable AC power combining for demanding PV systems

Maximum performance and protection for large PV plants: For large PV plants and demanding industrial installations, HIS offers AC combiner boxes for up to 1000 V AC. MCCB circuit breakers are used here, enabling precise protection and switching functions at high currents and with large inverter clusters.

Typical applications:

• Utility-scale solar parks

• Plants with large inverter blocks

• PV systems with increased grid requirements and high currents

Technical features:

• Up to 1000 V AC rated voltage

• MCCB circuit breakers (up to 160 A per input)

• 2 to 4 AC inputs

• High short-circuit strength

• Optional type 1+2 surge protection

• UV- and ozone-resistant GRP enclosures with IP65

For modern, high-performance inverters with increased AC rated voltage: This product category is designed for plants with 460 to 800 V AC and uses NH protection technology depending on the current. These combiners thus meet the requirements of modern, highly efficient inverter generations that operate at higher voltage levels.

Typical applications:

• High-performance C&I installations

• PV systems with high AC voltage inverters

• Plants with extended distribution structures

Technical features:

• 460–800 V AC

• NH switch-disconnectors

• 2 to 4 AC inputs

• Output currents up to 500 A

• Optional type 1+2 surge protection

• Robust industrial GRP enclosures

Safe AC power combining for typical 230/400 V PV systems: AC combiner boxes in the 400 V segment are used wherever several string inverters route their power onto a shared AC feeder. The devices are based on reliable NH switch-disconnector technology that has proven itself for years in industrial PV systems.

Typical applications:

• Commercial and industrial plants with several decentralised string inverters

• PV rooftop systems that require structured AC cabling

Technical features:

• 230/400 V AC grid voltage

• NH switch-disconnectors as the central protection and switching element

• 3 to 7 AC inputs for inverters

• Output currents up to 500 A

• Optional type 1+2 surge protection

• GRP enclosures, high protection ratings, UV-resistant

Grid and plant protection units handle the safety monitoring of the grid interface. They continuously check relevant grid parameters and ensure a defined, standard-compliant disconnection in the event of a fault. They thus form the central protective authority between the PV plant and the public grid and ensure a stable feed-in point.

Core functions:

• Monitoring of voltage, frequency and other grid parameters

• Automatic disconnection in accordance with VDE-AR-N 4105 / 4110

• Remotely controllable 4-pole isolating point

• Storage and evaluation of grid events

Coffrets structure the AC cable routing within the plant and create clear handover points between inverters, combiner boxes and main distribution boards. They reduce cable lengths, facilitate parallel cable routes and enable an installation-friendly organisation of complex AC layouts.

Core functions:

• Structured AC distribution points for clean layouts

• Reduced cable routing and simplified installation

• Clear connection spaces for service and maintenance

• Robust, weatherproof design

The NSHV combines the AC feed-ins of several combiners or inverters and distributes them onward to the grid connection point or to energy management systems. They provide a central platform for protection, metering and switching technology and enable a transparent and scalable AC architecture in large PV systems.

Core functions:

• Central combining of large AC powers

• Integration of switching, protection and metering technology

• Scalable structure for C&I and utility-scale plants

• Clear organisation of feed-in and outgoing circuits

Backup and energy management systems extend the AC infrastructure with functions for grid stability, load control and security of supply. They enable both backup power supply and active energy management in PV systems.

Core functions:

• Automatic switchover to backup supply in the event of a power failure

• Load management, peak shaving and self-consumption optimisation

• Integration of AC storage systems

• Flexible control for industrial and hybrid energy systems

On the AC side of photovoltaic plants, protection and switching technology take centre stage. The HISbox AC combiner boxes use robust industrial components such as NH switch-disconnector strips or MCCB circuit breakers to combine AC power reliably and limit electrical risks. Through clearly defined protective functions, both the inverter side and the higher-level AC distribution are effectively safeguarded.

• Short-circuit and overload protection via NH or MCCB switching devices

• Optional type 1+2 surge protection to protect the inverters

• High protection ratings up to IP65 for safe outdoor installation

• Standard-compliant design according to EN/IEC 61439-2

• Mechanically robust enclosures for long-term operational safety

These protective mechanisms ensure that the AC infrastructure operates reliably even at high currents and with complex plant layouts.

While the DC area often uses string monitoring, monitoring on the AC side focuses above all on system states and grid parameters. HISbox AC combiners can be integrated effortlessly into SCADA systems, monitoring platforms or grid protection solutions and supply the necessary information there for stable operational management.

• Integration into SCADA and plant monitoring systems

• Acquisition and evaluation of grid parameters via Grid & Plant Protection

• Status signals from switching devices (e.g. MCCB states, tripping)

• Temperature or operating-status messages depending on the operating environment

• Event logging and diagnostic data via HNA/HECI systems

This means the AC infrastructure not only supports safe operation but also enables predictive maintenance and a fast response in the event of a fault.