Weco SKT-15TL15kW three-phase string inverter, 2 MPPT

Overview

The SKT-15TL delivers 15kW and up to 16.5kVA into a 400V three-phase grid. Both MPP trackers take two strings at 30A, for a total PV array of up to 22.5kWp, and operate from 160 to 1000V. Maximum efficiency is 98.4% and European efficiency 98.0%. The IP66 enclosure measures 398×460×190mm and weighs 20.1kg, with forced-air cooling. Communication options include Wi-Fi, LAN, RS485 and GPRS/4G.

• 10, 15 and 20kW, 400V three-phase
• 2 MPPT, 1100V max., 160–1000V range
• PV array up to 150% of AC power
• 98.4% maximum efficiency
• IP66, 18.7–20.1kg
• CEI 0-21, VDE-AR-N 4105, EN 50549-1

How it works

The SKT-10TL, SKT-15TL and SKT-20TL are transformerless grid-tied inverters that feed PV power directly into a 380/400/415V three-phase grid. Two MPP trackers operate from 160 to 1000V, start at 180V and accept up to 1100V, with 620V rated input voltage. The PV array may be oversized to 150% of the AC rating, and grid voltage and frequency windows are adjustable.

On the 10kW model one tracker takes two strings at 30A and the other one string at 15A; the 15 and 20kW models take two strings and 30A on each tracker. Maximum AC apparent power is 11kVA, 16.5kVA and 22kVA respectively, with power factor adjustable from 0.8 leading to 0.8 lagging and THDi below 3% at rated power.

Key features

Maximum efficiency is 98.4% on all three models, with 97.8% European efficiency on the 10kW and 98.0% on the 15 and 20kW. The inverters integrate a DC switch, anti-islanding, AC overcurrent and short-circuit protection, DC reverse polarity protection, insulation monitoring and leakage current protection. Surge protection is type III on DC and AC, with type II available as an option.

Installation and compatibility

The housing is IP66, 398×460×190mm and about 20kg, with forced-air cooling and an operating range of −25 to +60°C up to 4000m. The datasheet lists IEC 62109-1/-2 for safety and VDE-AR-N 4105, EN 50549-1, CEI 0-21, UNE 206006/206007-1, RD 1699/661 and 413, IEC 61727/62116 and AS4777.2 as grid standards. WeCo currently publishes the datasheet for this range in Italian only.

Monitoring and settings

Communication options include Wi-Fi, LAN, RS485 and GPRS/4G, so the inverter can use a local network or a mobile data link. Monitoring runs through the WeCo app, which shows performance and energy in real time, and status is indicated by LEDs on the unit. Self-consumption is below 1W, and WeCo gives a five-year warranty on the series.

Questions and answers