DC Molded Case Circuit Breakers for Solar Array Main Protection | 63A-630A | Up to 1200V DC

Utility-Scale PV Array Recombiner Protection

In a 100 MW solar farm with twenty 5 MW inverter blocks, each inverter DC bus receives power from multiple string combiners aggregated through a recombiner panel. The UKM7Z-630 3P DC MCCB installed at the recombiner output protects the main DC feeder cable from the recombiner to the inverter DC input against overload and short circuit. The electronic trip unit LSI settings are coordinated with the downstream DC MCBs at the combiner box level so that a string-level fault clears locally without tripping the main MCCB, preserving power output from the remaining healthy strings in the same inverter block.

Battery Energy Storage Container Main DC Breaker

A 40-foot BESS container with 2.5 MWh of lithium-ion batteries typically deploys a UKM7Z-250 3P DC MCCB as the container-level main breaker between the battery DC bus and the PCS (Power Conversion System) DC input. The non-polarized design handles both charge and discharge current direction without derating, while the electronic trip unit ground-fault function detects DC leakage from the floating battery DC bus to the container chassis. The motor operator accessory allows the BMS or fire suppression system to remotely open the breaker within 100ms of a thermal runaway detection signal, isolating the battery stack from the DC bus before a cascading failure can propagate.

DC Fast Charging Station Feeder Protection

A DC fast charging plaza with eight 350 kW dispensers draws up to 1000A continuous from a shared DC bus fed by a central rectifier. UKM7Z-630 DC MCCBs at the rectifier output and at each dispenser group feeder provide selective protection so that a fault in one dispenser group feeder clears without shutting down the entire charging plaza. The Modbus communication module on each MCCB reports real-time current to the charger management system, enabling dynamic load balancing across dispensers based on actual demand rather than nameplate ratings.

DC Microgrid Bus-Tie Circuit Breakers

DC microgrids in commercial buildings and industrial facilities use UKM7Z DC MCCBs as bus-tie breakers between multiple DC sources (PV, battery, fuel cell) and the common DC bus feeding DC-native loads such as LED lighting, data center servers and variable-frequency drives. The electronic trip unit programmable LSI settings allow the bus-tie breaker to be reconfigured when additional generation or storage capacity is added to the microgrid, avoiding the need to replace the breaker when the system grows. The undervoltage release accessory provides automated bus isolation during utility grid outages, enabling the microgrid to island on battery power without back-feeding into the grid AC-DC converter.

Industrial DC Motor Control Center Main Breaker

Steel rolling mills, paper machines and mining conveyors powered by DC motors use UKM7Z-630 DC MCCBs as the main incoming breaker in DC motor control centers (MCCs). The adjustable instantaneous pickup prevents nuisance tripping during motor starting inrush (typically 6-8 times full-load current for 2-3 seconds on DC shunt motors) while still clearing bolted faults within one cycle. The shunt trip accessory is wired to the motor protection relay for coordinated shutdown sequencing that protects both the MCCB contacts and the motor commutator from excessive wear during fault conditions.

Deploy DC MCCBs in Your Renewable Energy System

• Complete Protection Schemes: Request a protection coordination report with UKM7Z trip settings optimized for your specific PV array or battery system topology.
• Type-Test Certification Package: Obtain IEC 60947-2 Annex P DC test reports and UL 489B compliance documents for AHJ and lender technical due diligence.
• Factory Acceptance Testing: Schedule a witnessed FAT at our Zhejiang facility where your breakers are tested to your specified trip settings before shipment.