Air Insulated Switchgears (AIS)

Gas Insulated Switchgears (GIS)

Ring Main Units

Distribution Transformers

                  L-Series Cast Resin Transformer

                  Oil Immersed Transformer

Busway System

Solar Power System

Oil Immersed Transformer

Parameter

Technical Specification

Oil Immersed Distribution Transformer

Hermitically sealed (without conservator) or with conservator

Rated power

25 – 3150kVA

Insulation level

According to IEC Um = 1.1, 3.6, 7.2, 12, 17.5, 24, 36kV
According to ANSI up to 36.5kV

Phases

3-phase (single phase is available on request)

Tappings

±2.5% or ±2x2.5% (or different ranges on request)

Voltage regulation

With off circuit tap changer
(Regulation with on-load tap changer is available on request)

Rated secondary voltage

From 220 to 800V

Short circuit impedance

Uk = 4% for P≤630kVA and Um≤24kV
Uk = 4% or 4.5% for P≤630kVA and Um≤36kV
Uk = 6% for P>630kVA

Rated frequency

50Hz (60Hz on request)

Vector groups

Yzn recommended up to 50kVA and Um≤24kV
Yzn recommended up to 100kVA with Um=36kV
Dyn for all other rated power (any vector group according to IEC Standards)

Material thermal class insulation

According to IEC 60085 class A

Temperature rise

Mean winding temperature rise: 65K
Top oil temperature rise: 60K
With ambient temperature in accordance with IEC 60076-1
The temperature of the cooling air should not exceed:

·         20°C yearly average

·         30°C monthly average of the hottest month

·         40°C at any time

For other ambient temperatures, winding and oil temperature rise should be adapted

Type of cooling

ONAN (Oil Natural Air Natural)

Dielectric liquid

Mineral oil according to IEC or ANSI standard
On request: silicon, midel, vegetal oil

Ability to withstand short-circuit

The transformers are designed to withstand the thermal and the dynamic effects resulting from a secondary short-circuit in accordance to IEC 60076-5

Sound level

The measurement (A-weighted sound pressure LpA) and the calculation of sound level (A-weighted sound level LwA) are done in accordance witih IEC 60076-10. The sound level requirements are in accordance with national standards.

Installations

Indoor and/or outdoor

HV & LV terminals

HV terminals: plug-in or porcelain bushings
LV terminals: busbars or porcelain bushings
On request: cable boxes according to client/manufacturer standard or norm (i.e. BS) requirements
On request: protective boots for HV/LV bushings

Accessories

·         Standard: lifting lugs, earthing terminal name and rating plate, oil filling plug, off circuit tap changer, bi-directional rollers if applicable (out of scope hanging pole transformer)

·         On request: padlock/locking device for HV plig-in bushings and/or tap changer, protection relay (DGCPT2, RIS, DMCR, etc.), oil level indicator, thermometer with or without contacts pressure relief device, pressure relay with contact, oil drain plug with/without sampling device, filling valve, drain valve, explosion vent, winding temperature indicator (OTI + WTI). Accessories for conservator: dehydrating breather, buchholz relay, drain plug, oil level indicator.