SOFAR 3.3KTLX-G33kW three-phase string inverter, 2 MPPT

Overview

The SOFAR 3.3KTLX-G3 is the smallest model of the 3.3-12KTLX-G3 series: a 3kW three-phase string inverter whose name reflects its 3.3kVA maximum apparent power. Two MPP trackers take one string each at up to 15A, and SOFAR recommends up to 4500Wp of PV, with full output available between 160 and 850V. The fanless 17kg unit reaches 98.4% maximum efficiency and, according to the manual, needs a 16A three-pole breaker with 0.1A residual current protection.

• Rated output from 3kW to 12kW, 230/400V three-phase
• Two MPPT, 140–1000V range, 1100V maximum input
• Apparent power 10% above rated output on most models
• Type II surge protection on DC and AC sides
• Fanless natural cooling, IP65, 430×385×182mm
• Bluetooth app setup, Wi-Fi or Ethernet stick logger

How it works

Each model converts the output of two independent PV inputs into 3/N/PE 230/400V AC. Both trackers work between 140 and 1000V with a 160V start-up voltage and a 650V rated input. The voltage window for full output ends at 850V and starts between 160V on the 3.3KTLX-G3 and 460V on the 12KTLX-G3. Models up to 11KTLX-G3 take one string per tracker at 15A; the 12KTLX-G3 accepts two strings and 30A on its second tracker.

The figure in SOFAR's model name is the maximum apparent power, not the rated output: the 3.3KTLX-G3 delivers 3kW and up to 3.3kVA, the 12KTLX-G3 12kW and up to 13.2kVA. Active power can be reduced from 0 to 100%, the power factor set between 0.8 leading and 0.8 lagging, and output is cut back automatically when grid frequency rises. Maximum efficiency is 98.4% up to 6kW and 98.5% from 8kW.

Key features

The inverters are transformerless, fanless and rated IP65, operating from -30 to +60°C up to 4000m altitude. A DC switch, reverse polarity protection, insulation and residual current monitoring, string fault monitoring and anti-islanding are built in, with Type II surge arresters on both PV and grid sides. The user manual lists arc-fault detection (AFCI) as an option. An I-V curve scan finds the true maximum power point when modules are partly shaded.

Installation and compatibility

Mount the inverter vertically or tilted back by up to 15°, never forwards or upside down, leaving 80cm above, 50cm below and 50cm at each side. Every inverter needs its own breaker, with no loads connected between inverter and breaker. The manual specifies five-core outdoor cable and three-pole breakers with 0.1A residual current protection, from 16A for the 3.3–5.5KTLX-G3 to 32A for the 11 and 12KTLX-G3.

Export limitation requires an external smart meter, supplied separately, at the grid connection point; the limit can be applied to total three-phase export or per phase. Up to 31 inverters can share an RS485 bus. The datasheet lists VDE-AR-N 4105, VDE V 0126-1-1, EN 50549-1, G98/G99 and UNE 217002 compliance, the manual also lists CEI 0-21, and SOFAR publishes C10/11 and TOR Erzeuger Type A certificates.

Monitoring and settings

Settings are made on the LCD or over Bluetooth with the app. A USB stick logger with Wi-Fi or Ethernet uploads production, alarms and status for remote monitoring, and firmware can be upgraded remotely through SofarCloud or locally from a USB drive. A logic interface accepts power-control signals from the grid operator according to EN 50549 and VDE-AR-N 4105.

Questions and answers