It is a distribution transformer rated for the everyday load at its site and built to carry seasonal or temporary peaks above that rating; its type designation ends in GZ. What sets it apart from a standard distribution transformer of the same rating is this short-time overload capability. ETENZ supplies it oil-immersed and sealed, in 50, 100 and 200 kVA, at S11 or S13 loss levels.
High Overload Distribution Transformer
For distribution contractors and utilities — 50–200 kVA, rated for everyday load, built for seasonal peaks; supplied alone or with a power E-House.
Distributed Node Power SupplyPackage Substation
Key Metrics
50–200kVA
Rated power
10–11kV
High voltage
100–340W
No-load loss
385–965kg
Total mass
Product Features
Seasonal peak duty
Rides through the weeks of the year when demand climbs above the nameplate rating, with the overload multiple and duration agreed for the site.
Seasonal peak duty
Rides through the weeks of the year when demand climbs above the nameplate rating, with the overload multiple and duration agreed for the site.
Right-sized rating
Rated for the everyday load rather than the peak, the unit carries less no-load loss all year: 150 W at 100 kVA against 240 W at 200 kVA in S13.
S11 or S13 losses
S13 cuts no-load loss by 23–29% against S11 at the same rating, with the same load loss and 4.0% impedance across 50–200 kVA.
Fully sealed tank
A sealed corrugated tank with no conservator keeps the insulating oil out of contact with outside air.
10–11 kV networks
One design serves 10, 10.5 and 11 kV networks, with a 0.4 kV LV side and the tapping range and vector group chosen per order.
Product Details
S stands for three-phase and the digits after it for the loss level, 11 or 13. M marks the sealed tank, and the bracket after it holds the insulation thermal class. The rated power in kVA and the voltage class in kV follow, and the suffix GZ marks high overload capability. S13-M(□)-100/10(GZ) therefore reads: three-phase, loss level 13, sealed, 100 kVA, 10 kV class, high overload, with □ standing for the insulation thermal class confirmed for the project.
The nameplate rating is the load carried continuously, so it is chosen for what the distribution point draws most of the year. High overload capability covers the weeks when harvest, irrigation, holiday or tourist demand lifts the load above it. The overload multiple, its duration and the ambient temperature they apply to are agreed with the order from the site’s peak profile — everyday load, peak kVA, how long the peak lasts and how often it recurs — together with the insulation thermal class shown in the type designation.
At 50, 100 and 200 kVA, S13 has a no-load loss of 100, 150 and 240 W against 130, 200 and 340 W for S11, 23–29% lower; load loss is identical at each rating. No-load current is 0.8%, 0.7% and 0.6% on S13 against 1.1%, 1.0% and 0.9% on S11. No-load loss runs every hour the transformer is energised, so the 100 W gap at 200 kVA comes to about 876 kWh a year.
HV is 10, 10.5 or 11 kV with a tapping range of ±5% or ±2×2.5%, and LV is 0.4 kV. Short-circuit impedance is 4.0% at every rating. The vector group is Dyn11 or Yyn0, both with the LV neutral brought out, and load loss is listed for each: 910, 1580 and 2730 W with Dyn11 and 870, 1500 and 2600 W with Yyn0, at 50, 100 and 200 kVA.
M in the type designation marks a sealed tank: corrugated fins on the front and sides, no conservator, and the oil kept out of contact with outside air. The HV and LV bushings sit on the cover. Total mass is 385, 585 and 875 kg for S11 at 50, 100 and 200 kVA, and 425, 645 and 965 kg for S13. Outline dimensions follow the order drawing.
Delivery Scope Options
Scope 1
Single Unit or Complete Package Supply
Scope 1Single Unit or Complete Package Supply
Transformers are supplied as single units against the order schedule, or as a complete package together with the protective enclosure, the temperature controller and the cooling fans. The active part is wound, assembled and routine-tested at the works and shipped as a complete unit; the assembly interface for the accessories follows the transport conditions. Where the transformer is to arrive together with a prefabricated power module, the E-House line takes on the enclosure, the internal arrangement and the foundation fixing, and the transformer is delivered as equipment housed within it.
Scope Includes:
Single unit or complete package
Complete-unit shipment and assembly interface
Foundation and fixing interface
In-cabin delivery handled by the E-House line
Technical Specifications
Product form
Three-phase oil-immersed distribution transformer with high overload capability; silicon-steel core; sealed tank
Type designation
S□-M(□)-□/□(GZ): loss level, sealed type, insulation thermal class, rated power / voltage class, high overload
Rated power
50 / 100 / 200
kVA
Loss level
S11 or S13
High voltage
10 / 10.5 / 11
kV
HV tapping range
±5 or ±2×2.5
%
Low voltage
0.4
kV
Vector group
Dyn11 or Yyn0
Short-circuit impedance
4.0
%
No-load loss, S11
50 kVA: 130; 100 kVA: 200; 200 kVA: 340
W
No-load loss, S13
50 kVA: 100; 100 kVA: 150; 200 kVA: 240
W
Load loss, Dyn11 / Yyn0 (S11 and S13)
50 kVA: 910 / 870; 100 kVA: 1580 / 1500; 200 kVA: 2730 / 2600
W
No-load current, S11
50 kVA: 1.1; 100 kVA: 1.0; 200 kVA: 0.9
%
No-load current, S13
50 kVA: 0.8; 100 kVA: 0.7; 200 kVA: 0.6
%
Total mass, S11
50 kVA: 385; 100 kVA: 585; 200 kVA: 875
kg
Total mass, S13
50 kVA: 425; 100 kVA: 645; 200 kVA: 965
kg
Overload multiple and duration
Agreed for the project’s peak load profile
Insulation thermal class, frequency, dimensions
Confirmed for the project
| Parameter | Specification |
|---|---|
| Product form | Three-phase oil-immersed distribution transformer with high overload capability; silicon-steel core; sealed tank |
| Type designation | S□-M(□)-□/□(GZ): loss level, sealed type, insulation thermal class, rated power / voltage class, high overload |
| Rated power | 50 / 100 / 200 kVA |
| Loss level | S11 or S13 |
| High voltage | 10 / 10.5 / 11 kV |
| HV tapping range | ±5 or ±2×2.5 % |
| Low voltage | 0.4 kV |
| Vector group | Dyn11 or Yyn0 |
| Short-circuit impedance | 4.0 % |
| No-load loss, S11 | 50 kVA: 130; 100 kVA: 200; 200 kVA: 340 W |
| No-load loss, S13 | 50 kVA: 100; 100 kVA: 150; 200 kVA: 240 W |
| Load loss, Dyn11 / Yyn0 (S11 and S13) | 50 kVA: 910 / 870; 100 kVA: 1580 / 1500; 200 kVA: 2730 / 2600 W |
| No-load current, S11 | 50 kVA: 1.1; 100 kVA: 1.0; 200 kVA: 0.9 % |
| No-load current, S13 | 50 kVA: 0.8; 100 kVA: 0.7; 200 kVA: 0.6 % |
| Total mass, S11 | 50 kVA: 385; 100 kVA: 585; 200 kVA: 875 kg |
| Total mass, S13 | 50 kVA: 425; 100 kVA: 645; 200 kVA: 965 kg |
| Overload multiple and duration | Agreed for the project’s peak load profile |
| Insulation thermal class, frequency, dimensions | Confirmed for the project |
Product FAQs
The overload multiple, its duration and the ambient temperature they apply to are agreed for each project and stated in the technical data with the order. Send the everyday load, the expected peak in kVA, how long the peak lasts, how often it recurs and the highest ambient temperature in the peak season.
Choose the rating for the load the transformer carries most of the year, then check the peak against the agreed overload capability. A larger rating adds no-load loss for every hour of the year: 90 W more at 200 kVA than at 100 kVA in S13. For more than 200 kVA, or a load that stays high all year, see the Oil-Immersed Distribution Transformer, rated 30–2500 kVA.
Price mainly depends on the rating, the loss level, the HV and tapping range, the vector group, the overload requirement and the accessories. For a quotation, send the network voltage and frequency, the rating or everyday load, the peak load and its duration, the vector group, the site altitude and ambient temperature range, the mounting arrangement and the documents the destination country requires.
Yes. The transformer can be supplied on its own, or arrive installed in a power E-House together with the MV switchgear and LV distribution. The ETENZ E-House line provides the enclosure, the internal layout and the HVAC and fire protection systems, for example the Integrated E-House or the MV Switchgear E-House, and the transformer and enclosure layout is confirmed together before dispatch.
HV of 10, 10.5 or 11 kV and LV of 0.4 kV are the listed values. Frequency, other voltages and the vector group are confirmed with the order, and the document package follows the destination country, with drawings, test records, the packing list and installation and maintenance instructions.
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