SZ / SSZ / SFSZ 35–220 kV OLTC power transformers for substations
SZ, SSZ and SFSZ are three-phase oil-immersed transformers with on-load tap changers (OLTC) for the 35–220 kV classes, rated from 5 to 240 MVA. Two- and three-winding models link 220, 110 and 35 kV networks and supply substations, power plants and industrial sites.
- 220 kV
- SFSZ-240000/220 (240 MVA), SSZ20-180000/220 (180 MVA): (220 ±8×1.25 %)/121/38.5 kV, YNyn0d11
- 220 kV start-up and standby
- SFFZ-126000/220: 126/70-70 MVA, split winding 10.5-10.5 kV
- 110 kV
- SZ-100000/110: 100 MVA, (110 ±8×1.25 %)/37/6.3 kV; SSZ20-50000/110: 50 MVA, no-load loss ≤29.6 kW, short-circuit loss ≤192 kW; SZ-5000/110 (auxiliary-service transformer)
- 66 kV
- SZ-25000/63: 25 MVA, (63 ±8×1.25 %)/10.5 kV
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Transformers of the 35–220 kV classes are installed at distribution and regional substations, power plants, industrial enterprises and renewable energy stations. The series covers three-phase oil-immersed two- and three-winding units with on-load tap changing, equivalents of the ТДН, ТДТН, ТРДН and ТДЦТН 35–220 kV types.
At 220 kV the range includes the three-winding SFSZ-240000/220 rated 240 MVA and the SSZ20-180000/220 rated 180 MVA, with voltages of (220 ±8×1.25 %)/121/38.5 kV and vector group YNyn0d11. In the SFSZ-240000/220 the winding ratings are 240/240/120 MVA, the top-oil temperature rise per the manufacturer is 54.8 K and the average winding temperature rise is 64.8 K. The energy-efficient SSZ20 series is fitted with several online monitoring devices. The SFFZ-126000/220 start-up and standby unit, rated 126 MVA, has a split LV winding of 10.5–10.5 kV (70 + 70 MVA) and a short-circuit voltage of 14 %; it is used at power plants and in the silicon industry.
The 110 kV class is represented by the three-winding SZ-100000/110 (100 MVA, (110 ±8×1.25 %)/37/6.3 kV, ONAN) and the SSZ20-50000/110 (50 MVA, (110 ±8×1.25 %)/(38.5 ±2×2.5 %)/10.5 kV). The latter has a no-load loss of up to 29.6 kW, a short-circuit loss of up to 192 kW and noise of up to 60 dB(A). The auxiliary-service transformer SZ-5000/110 (5 MVA, 110/10.5 kV) supplies ultra-high-voltage substations. For 66 kV networks there is the SZ-25000/63 (25 MVA, (63 ±8×1.25 %)/10.5 kV) with full insulation, and for 35 kV networks the compact SZ-31500/35 (31.5 MVA, (35 ±3×2.5 %)/10.5 kV) with a short-circuit loss of 82.7 kW and an oil temperature rise of 47.5 K.
The short-circuit withstand of the windings is confirmed by computational modelling. Stray fields and additional losses are reduced by design measures, oil is distributed evenly through the windings, heating is low, and no-load loss and noise are small. Cooling is natural oil (ONAN) or with air blast (ONAF), which lowers auxiliary power consumption. The insulation levels of the SFSZ-240000/220, per the manufacturer, are SI750 LI950 AC395 for the HV line terminal and LI400 AC200 for its neutral, with LI480 AC200 and LI325 AC140 on the MV side.
The main customers of the series work in the grid sector, but the transformers are equally used at converter substations, power plants, and metallurgical and chemical works.
Technical specifications
| 220 kV | SFSZ-240000/220 (240 MVA), SSZ20-180000/220 (180 MVA): (220 ±8×1.25 %)/121/38.5 kV, YNyn0d11 |
|---|---|
| 220 kV start-up and standby | SFFZ-126000/220: 126/70-70 MVA, split winding 10.5-10.5 kV |
| 110 kV | SZ-100000/110: 100 MVA, (110 ±8×1.25 %)/37/6.3 kV; SSZ20-50000/110: 50 MVA, no-load loss ≤29.6 kW, short-circuit loss ≤192 kW; SZ-5000/110 (auxiliary-service transformer) |
| 66 kV | SZ-25000/63: 25 MVA, (63 ±8×1.25 %)/10.5 kV |
| 35 kV | SZ-31500/35: 31.5 MVA, (35 ±3×2.5 %)/10.5 kV |
| Cooling | ONAN, ONAN/ONAF |
| Noise | ≤60 dB(A) (SSZ20-50000/110) |
| Options | built-in online monitoring sensors |
Replacement for
ТМН-6300/35, ТДН-16000/110, ТДТН-40000/110, ТРДН-63000/110, ТДТН-40000/220, ТРДЦН-160000/220
selected by purpose and main parameters, please confirm with our manager
Request a price and lead time
SZ / SSZ / SFSZ 35–220 kV OLTC power transformers for substations. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8504 23 00 00 |
|---|---|
| HS, 6 digits | 8504 23 |
| CN (EU) | 8504 23 00 |
| HTSUS (USA) | 8504 23 00 80 |
| China customs tariff | 8504 23 10 00 8504 23 20 00 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Which 220 kV transformers does the series include?
The three-winding SFSZ-240000/220 rated 240 MVA and the SSZ20-180000/220 rated 180 MVA, with voltages of (220 ±8×1.25 %)/121/38.5 kV. For plant start-up and standby schemes there is the SFFZ-126000/220 rated 126 MVA with a split 10.5–10.5 kV winding.
What are the losses and noise of the SSZ20-50000/110?
No-load loss of up to 29.6 kW, short-circuit loss of up to 192 kW, noise of up to 60 dB(A). The rating is 50 MVA and the voltages are (110 ±8×1.25 %)/(38.5 ±2×2.5 %)/10.5 kV.
What cooling do the transformers of the series have?
Natural oil cooling ONAN or combined ONAN/ONAF with air blast. The SZ-100000/110 rated 100 MVA operates with ONAN cooling.
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