SZ18-M-3150/35-NX3 - TAIXUANTECH

SZ18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer

35kV Oil-Immersed Power Transformer Series

SZ18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer

The SZ18-M-3150/35-NX3 is a three-phase oil-immersed power transformer with an on-load tap changer, rated capacity of 3150kVA and a high-voltage side rating of 35kV. The transformer is designed with S18 loss level, achieving Class 3 energy efficiency (NX3) according to GB 20052-2024. It features a robust oil-immersed structure with high reliability, strong short-circuit withstand capability, and low noise. The core is made of high-quality cold-rolled grain-oriented silicon steel, and windings use oxygen-free copper conductors. Equipped with an on-load tap changer, it can automatically regulate voltage without interrupting power supply, making it suitable for substations, industrial and mining enterprises, and power transmission applications requiring stable voltage regulation.

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 SZ18-M-3150/35-NX3

No-Load Loss ≤2.6 kW

Rated Capacity 3150 kVA

No-Load Current ≤0.4%

Phase 3-phase

Load Loss (75°C) ≤23.5 kW

Rated Voltage Ratio 35/10.5 kV

Short-Circuit Impedance 7.0%

HV Tapping Range ±3×2.5%

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

Rated Frequency 50 Hz

Noise (Sound Pressure Level) ≤65 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 loss of 2.6 kW and load loss of 23.5 kW meeting the required limits for 35kV power transformers.

On-Load Tap Changer (OLTC)

Equipped with an on-load tap changer, the transformer can automatically regulate voltage without interrupting power supply. Ideal for grids with frequent voltage fluctuations and critical load applications.

High Reliability & Strong Short-Circuit Withstand

Optimized core and winding design, combined with a robust oil-immersed structure, ensures stable operation under heavy loads with strong short-circuit resistance and long service life.

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, on-load tap-changer, power transformer, 2000-31500kVA
Model	Rated Capacity (kVA)	HV (kV)	HV Tapping Range	LV (kV)	Vector Group	No-Load Loss (kW)	Load Loss (75°C) (kW)	Impedance Voltage (%)
SZ22-M-2000/35	2000	35	±3×2.5%	6.3，10.5	Yd11	1.288	17.290	6.5
SZ20-M-2000/35	2000	35	±3×2.5%	6.3，10.5	Yd11	1.472	17.290	6.5
SZ18-M-2000/35	2000	35	±3×2.5%	6.3，10.5	Yd11	1.840	18.200	6.5
SZ22-M-2500/35	2500	35	±3×2.5%	6.3，10.5	Yd11	1.526	18.620	6.5
SZ20-M-2500/35	2500	35	±3×2.5%	6.3，10.5	Yd11	1.744	18.620	6.5
SZ18-M-2500/35	2500	35	±3×2.5%	6.3，10.5	Yd11	2.180	19.600	6.5
SZ22-M-3150/35-NX1	3150	35，38.5	±3×2.5%	6.3，10.5	Yd11	1.800	22.200	7.0
SZ20-M-3150/35-NX2	3150	35，38.5	±3×2.5%	6.3，10.5	Yd11	2.100	22.200	7.0
SZ18-M-3150/35-NX3	3150	35，38.5	±3×2.5%	6.3，10.5	Yd11	2.600	23.500	7.0
SZ22-4000/35-NX1	4000	35，38.5	±3×2.5%	6.3，10.5	Yd11	2.100	26.200	7.0
SZ20-4000/35-NX2	4000	35，38.5	±3×2.5%	6.3，10.5	Yd11	2.500	26.200	7.0
SZ18-4000/35-NX3	4000	35，38.5	±3×2.5%	6.3，10.5	Yd11	3.100	27.600	7.0
SZ22-5000/35-NX1	5000	35，38.5	±3×2.5%	6.3，10.5	Yd11	2.600	30.800	7.0
SZ20-5000/35-NX2	5000	35，38.5	±3×2.5%	6.3，10.5	Yd11	3.000	30.800	7.0
SZ18-5000/35-NX3	5000	35，38.5	±3×2.5%	6.3，10.5	Yd11	3.700	32.500	7.0
SZ22-6300/35-NX1	6300	35，38.5	±3×2.5%	6.3，10.5	Yd11	3.100	33.000	7.5
SZ20-6300/35-NX2	6300	35，38.5	±3×2.5%	6.3，10.5	Yd11	3.700	33.000	7.5
SZ18-6300/35-NX3	6300	35，38.5	±3×2.5%	6.3，10.5	Yd11	4.500	34.900	7.5
SZ22-8000/35-NX1	8000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	4.300	36.500	7.5
SZ20-8000/35-NX2	8000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	5.100	36.500	7.5
SZ18-8000/35-NX3	8000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	6.300	38.600	7.5
SZ22-10000/35-NX1	10000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	5.100	43.200	7.5
SZ20-10000/35-NX2	10000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	6.000	43.200	7.5
SZ18-10000/35-NX3	10000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	7.400	45.600	7.5
SZ22-12500/35-NX1	12500	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	6.000	51.100	7.5
SZ20-12500/35-NX2	12500	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	7.100	51.100	7.5
SZ18-12500/35-NX3	12500	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	8.700	54.000	7.5
SZ22-16000/35-NX1	16000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	7.200	63.300	7.5
SZ20-16000/35-NX2	16000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	8.500	63.300	7.5
SZ18-16000/35-NX3	16000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	10.500	66.800	7.5
SZ22-20000/35-NX1	20000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	8.500	74.400	7.5
SZ20-20000/35-NX2	20000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	10.100	74.400	7.5
SZ18-20000/35-NX3	20000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	12.400	78.600	7.5
SZ22-25000/35-NX1	25000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	10.100	88.000	10.0
SZ20-25000/35-NX2	25000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	11.900	88.000	10.0
SZ18-25000/35-NX3	25000	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	14.600	92.900	10.0
SZ22-31500/35-NX1	31500	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	12.000	104.400	10.0
SZ20-31500/35-NX2	31500	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	14.200	104.400	10.0
SZ18-31500/35-NX3	31500	35，38.5	±3×2.5%	6.3，6.6，10.5	YNd11	17.400	110.200	10.0
Note： 1.±3×2.5% 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.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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SZ18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer

35kV Oil-Immersed Power Transformer Series

SZ18-M-3150/35-NX3 Three-Phase Oil-Immersed Hermetically Sealed Power Transformer