S18-M-3150/35-NX3 - TAIXUANTECH

S18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer

35kV Oil-Immersed Power Transformer Series

S18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer

The S18-M-3150/35-NX3 is a three-phase oil-immersed power transformer with a rated capacity of 3150kVA and a high-voltage side rating of 35kV. The transformer features a fully sealed tank structure that isolates the transformer oil from air, effectively delaying insulation aging. It adopts ONAN (Oil Natural Air Natural) cooling, ensuring reliable heat dissipation under natural oil circulation and air convection. The core is made of high-quality cold-rolled silicon steel, and both high and low voltage windings use oxygen-free copper conductors. The product is designed with S18 loss level, achieving Class 3 energy efficiency (NX3) according to GB 20052-2024, and complying with GB/T 6451-2023 technical requirements for 35kV power transformers. It is suitable for 35kV power systems, providing reliable power supply for substations, industrial and mining enterprises, and power transmission applications.

Industrial & Commercial Utility & Grid

Rated Capacity: 3150 kVA
Rated Voltage Ratio: 35/10.5 kV
Connection Group: Yd11
Cooling Method: ONAN
Energy Efficiency Class: NX3
Standard：IEC 60076, GB/T 6451-2023

Product Details

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Product Model S18-M-3150/35-NX3

No-Load Loss ≤2.4 kW

Rated Capacity 3150 kVA

No-Load Current ≤0.36%

Phase 3-phase

Load Loss (75°C) ≤21.9 kW

Rated Voltage Ratio 35/10.5 kV

Short-Circuit Impedance 7.0%

HV Tapping Range ±2×2.5%

Temperature Rise Limit Top oil ≤55K, Winding ≤65K

Rated Frequency 50 Hz

Noise (Sound Pressure Level) ≤66 dB(A)

Connection Group Yd11 (Dyn11 available upon request)

Protection Degree IP54

Cooling Method ONAN

Standard IEC 60076, GB/T 6451-2023

Insulation Class A, LI200 AC85 / AC5

Energy Efficiency Class NX3

01.

Core advantages

Class 3 Energy Efficiency (NX3)

Complies with GB 20052-2024 Class 3 energy efficiency standard, with no-load and load losses meeting the required limits for 35kV power transformers.

Fully Sealed Structure

Fully sealed tank isolates transformer oil from air, slows down insulation aging, and extends service life with minimal maintenance.

Low Loss Design (S18 Level)

Optimized core and coil design achieves low no-load and load losses, ensuring reliable and efficient operation for substations, industrial and mining enterprises, and power transmission applications.

02.

Application scenarios

No data was found

01.

Authoritative Certification

Our transformers are CE certified, ensuring full compliance with EU safety, health, and environmental standards.

Our transformers are UL certified, confirming they meet rigorous ANSI/IEEE safety standards for North American market entry.

ASTA

Our transformers have obtained ASTA type-test certification, verifying IEC 60076 compliance.

EAC

Our transformers are EAC certified, ensuring compliance with safety and EMC regulations for the Eurasian market.

SASO

We provide SASO-compliant transformers and assist clients in obtaining the Batch Certificate of Conformity (CoC) through the SABER platform.

02.

Quality Assurance

Partner Factory Audit

Regular on-site audits of partner factories to verify ISO, CE, and UL certifications.

Full-Process Quality Control

From raw material inspection to pre-shipment final inspection, every unit is checked against specifications.

Comprehensive Test Reports

Each transformer includes a detailed factory test report. 100% full inspection before dispatch.

Third-Party Inspection Support

SGS, BV, or other accredited third-party inspection available upon customer request.

01.

Technical Documents

No data was found

02.

Certification Materials

No data was found

35kV Oil-Immersed Power Transformer Series – Full Specifications

35kV, 3-phase, 2-winding, oil-immersed, off-circuit tap-changer, power transformer, 630-31500kVA
Model	Rated Capacity (kVA)	HV (kV)	HV Tapping Range	LV (kV)	Vector Group	No-Load Loss (kW)	Load Loss (75°C) (kW)	Impedance Voltage (%)
S22-M-630/35	630	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.462	7.097	6.5
S20-M-630/35	630	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.528	7.097	6.5
S18-M-630/35	630	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.660	7.470	6.5
S22-M-800/35	800	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.546	8.484	6.5
S20-M-800/35	800	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.624	8.484	6.5
S18-M-800/35	800	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.780	8.930	6.5
S22-M-1000/35	1000	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.644	10.355	6.5
S20-M-1000/35	1000	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.736	10.355	6.5
S18-M-1000/35	1000	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.920	10.900	6.5
S22-M-1250/35	1250	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.784	12.540	6.5
S20-M-1250/35	1250	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.896	12.540	6.5
S18-M-1250/35	1250	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.120	13.200	6.5
S22-M-1600/35	1600	35	±2×2.5%	3.15，6.3，10.5	Yd11	0.945	15.010	6.5
S20-M-1600/35	1600	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.080	15.010	6.5
S18-M-1600/35	1600	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.350	15.800	6.5
S22-M-2000/35	2000	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.218	16.530	6.5
S20-M-2000/35	2000	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.392	16.530	6.5
S18-M-2000/35	2000	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.740	17.400	6.5
S22-M-2500/35	2500	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.435	17.670	6.5
S20-M-2500/35	2500	35	±2×2.5%	3.15，6.3，10.5	Yd11	1.640	17.670	6.5
S18-M-2500/35	2500	35	±2×2.5%	3.15，6.3，10.5	Yd11	2.050	18.600	6.5
S22-M-3150/35-NX1	3150	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	1.700	20.700	7.0
S20-M-3150/35-NX2	3150	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.000	20.700	7.0
S18-M-3150/35-NX3	3150	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.400	21.900	7.0
S22-M-4000/35-NX1	4000	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.000	24.600	7.0
S20-M-4000/35-NX2	4000	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.300	24.600	7.0
S18-M-4000/35-NX3	4000	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.900	25.900	7.0
S22-M-5000/35-NX1	5000	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.400	28.200	7.0
S20-M-5000/35-NX2	5000	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.800	28.200	7.0
S18-M-5000/35-NX3	5000	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	3.500	29.700	7.0
S22-M-6300/35-NX1	6300	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	2.900	31.500	8.0
S20-M-6300/35-NX2	6300	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	3.400	31.500	8.0
S18-M-6300/35-NX3	6300	35，38.5	±2×2.5%	3.15，6.3，10.5	Yd11	4.200	33.300	8.0
S22-M-8000/35-NX1	8000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	4.000	34.600	8.0
S20-M-8000/35-NX2	8000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	4.700	34.600	8.0
S18-M-8000/35-NX3	8000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	5.800	36.500	8.0
S22-M-10000/35-NX1	10000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	4.800	40.800	8.0
S20-M-10000/35-NX2	10000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	5.700	40.800	8.0
S18-M-10000/35-NX3	10000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	7.000	43.000	8.0
S22-M-12500/35-NX1	12500	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	5.500	48.400	8.0
S20-M-12500/35-NX2	12500	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	6.500	48.400	8.0
S18-M-12500/35-NX3	12500	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	8.000	51.100	8.0
S22-M-16000/35-NX1	16000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	6.700	59.200	8.0
S20-M-16000/35-NX2	16000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	7.900	59.200	8.0
S18-M-16000/35-NX3	16000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	9.700	62.500	8.0
S22-M-20000/35-NX1	20000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	7.900	71.600	8.0
S20-M-20000/35-NX2	20000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	9.400	71.600	8.0
S18-M-20000/35-NX3	20000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	11.500	75.500	8.0
S22-M-25000/35-NX1	25000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	9.400	84.600	10.0
S20-M-25000/35-NX2	25000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	11.100	84.600	10.0
S18-M-25000/35-NX3	25000	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	13.600	89.300	10.0
S22-M-31500/35-NX1	31500	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	11.100	100.800	10.0
S20-M-31500/35-NX2	31500	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	13.100	100.800	10.0
S18-M-31500/35-NX3	31500	35，38.5	±2×2.5%	3.15，3.3，6.3，6.6，10.5	YNd11	16.200	106.400	10.0
Note： 1.±2×2.5% is shown as the default tapping range in this table. Other tapping ranges are available upon request. 2.Other high and low voltages are available upon request. 3.Vector group options: Yd11 or YNd11 as listed in the table. Other vector groups are available upon request. 4.Efficiency classes (NX1/NX2/NX3) apply to 3150kVA and above, in accordance with GB 20052-2024. 5.For IEC, ANSI, or other standards, or special frequency requirements, please contact us for a customized datasheet.

* For specific product requests, please Contact Us for customized solutions to your needs.

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S18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer

35kV Oil-Immersed Power Transformer Series

S18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer