Quick Answer

A 1000 kVA 15 kV/0.8 kV oil-immersed transformer for an Italian utility project is a three-phase, EU Ecodesign Tier 2 compliant distribution transformer that steps the 15 kV medium-voltage network down to an 800 V low-voltage bus inside a cabina MT/BT or a dedicated MV/LV substation. Italian connection practice allows transformers up to 1600 kVA on 15 kV feeders at 6% impedance, so 1000 kVA is a standard, freely permittable size. The first line item Italian utilities check is Ecodesign compliance under Regulation (EU) 548/2014 Tier 2 — for a 1000 kVA liquid-immersed unit, no-load loss ≤ 770 W (Ao class) and load loss ≤ 10,500 W (Ck class) — together with CE marking, a Dyn11 vector group and an LV neutral brought out and earthed.

Product Overview

This is a three-phase, 50 Hz oil-immersed distribution transformer rated 1000 kVA, with a primary voltage of 15 kV (17.5 kV equipment class, BIL 95 kV) and a secondary voltage of 0.8 kV. Both HV and LV windings are copper. The active part is sealed inside a corrugated-fin steel tank with no conservator, so the insulating oil never contacts air, never needs sampling, filtration or topping-up, and the unit is genuinely maintenance-free for its 25-year design life. Impedance is 6%, the value Italian connection rules assume for MT/BT transformers.

The 800 V low-voltage side is the point of this rating: at 1000 kVA it halves the LV current to roughly 720 A versus 1440 A at 400 V, which means smaller LV cables, busbars and switchgear — a real cost advantage for battery energy storage PCS, rectifier and DC industrial loads, PV plants and large utility districts. 400 V / 415 V secondaries remain available on request for conventional Italian LV networks.

It is built for Italian utility and infrastructure work: cabine MT/BT operated by local distribution companies, industrial district substations, utility and EPC tenders, and renewable plants connecting to the 15 kV / 20 kV distribution grid. Standard supply includes oil-temperature monitoring with alarm/trip contacts and an RS485/Modbus RTU interface, readable by the site SCADA. Manufactured under ISO 9001, ISO 14001 and ISO 45001, designed and tested to IEC 60076-1/-2/-3/-5/-10 and EN 50588-1 / EN 50629, and CE marked with losses declared per Regulation (EU) 548/2014 Tier 2.

Why Italian Utility Projects Specify Sealed Oil-Immersed

Our recommendation: for outdoor compounds, cabine MT/BT and industrial districts, specify a hermetically sealed oil-immersed transformer. Reserve cast resin dry type for indoor electrical rooms, underground substations and any site where Italian fire regulation (DM 03/08/2015) rules out combustible oil.

Two reasons drive the Italian specification. First, total cost: an oil-immersed unit costs less per kVA and its sealed tank removes every periodic oil-maintenance task. Second, integration: Italian MV/LV practice is a delta HV winding with an earthed LV star point — exactly the Dyn11 group this transformer ships in — and the 1000 kVA rating sits comfortably inside the 1600 kVA ceiling that Italian utilities apply to 15 kV feeders at 6% impedance.

EU Ecodesign Tier 2 and 20-Year Running Cost

A 1000 kVA transformer on a utility network stays energised 24 hours a day, so no-load loss runs 8,760 hours a year even at night load. Under Regulation (EU) 548/2014 Tier 2 — mandatory across the EU since 1 July 2021 — a 1000 kVA liquid-immersed unit must not exceed 770 W no-load loss (Ao class) and 10,500 W load loss (Ck class), and the guaranteed values must be declared on the nameplate. Italian utilities frequently specify below these limits, and so do we:

Key Features

• EU Ecodesign Tier 2 compliant — guaranteed losses 650 W / 8,400 W, declared on the nameplate per Reg. (EU) 548/2014; low-loss step-lap core in grain-oriented steel.
• Hermetically sealed corrugated tank — no conservator, no oil sampling, filtration or topping-up for the full 25-year design life.
• 800 V LV, half the current — ≈720 A per phase at 1000 kVA vs ≈1440 A at 400 V, so smaller LV cables, busbars and switchgear for BESS PCS, rectifiers and PV. 400/415 V on request.
• Copper HV and LV windings, Dyn11 with earthed LV neutral — the standard Italian MT/BT configuration, with lower losses and better short-circuit withstand (type-tested to IEC 60076-5).
• Built for the Italian site — seismic design to NTC 2018, C4/C5-M anti-corrosion coating, IP54 cable boxes, fluororubber sealing from -25 °C to +55 °C, ≤60 dB(A) at 1 m.
• Smart- and environment-ready — oil temperature alarm/trip contacts and RS485/Modbus RTU as standard, 4G/LoRa optional; mineral oil to IEC 60296 or biodegradable natural ester for protected areas.

Typical Applications

• MV/LV prefabricated substations (cabine MT/BT) and utility substations on 15 kV / 20 kV feeders
• PV plants and BESS connecting to the Italian MV grid
• Industrial plants with DC, rectifier or electrolysis loads
• Infrastructure — rail, metro, airports and ports; YBW compact substation packages with 15/24 kV RMUs

Standards and Certifications

Designed and tested in accordance with IEC 60076-1 (general), IEC 60076-2 (temperature rise), IEC 60076-3 (insulation levels and dielectric tests), IEC 60076-5 (short-circuit withstand) and IEC 60076-10 (sound level), plus EN 50588-1 and EN 50629 for European distribution transformers. Energy performance complies with Regulation (EU) 548/2014 Tier 2, with guaranteed losses declared on the nameplate. CE marked, with the EU Declaration of Conformity issued with every unit; an EU authorised responsible person under Regulation (EU) 2023/988 (GPSR) can be arranged. Connection aspects follow the Italian framework (CEI 0-16 and the CEI 14 series) — Dyn11 vector group, 6% impedance and earthed LV neutral are supplied as standard. Manufactured under ISO 9001, ISO 14001 and ISO 45001. Third-party type test reports (CNAS-accredited laboratory, KEMA or equivalent) available on request. Harmonic duty designed with reference to IEEE C57.110.