SZ22-31500/66-NX1 - TAIXUANTECH

SZ22-31500/66-NX1 Three-Phase Oil-Immersed On-Load Tap-Changer Power Transformer

66kV Oil-Immersed Power Transformer Series

SZ22-31500/66-NX1 Three-Phase Oil-Immersed On-Load Tap-Changer Power Transformer

The SZ22-31500/66-NX1 is a three-phase oil-immersed on-load tap-changer power transformer with a rated capacity of 31500kVA and a high-voltage side rating of 66kV. It is designed with S22 loss level, achieving Class 1 energy efficiency (NX1) according to GB 20052-2024. Equipped with an on-load tap changer, it can automatically regulate voltage without interrupting power supply, making it ideal for high-voltage grids with frequent voltage fluctuations. The core is made of high-quality cold-rolled grain-oriented silicon steel, and windings use oxygen-free copper conductors, ensuring low loss, low partial discharge, low temperature rise, and strong short-circuit withstand capability. It is suitable for 66kV power systems, providing reliable and energy-efficient power supply for substations, large industrial parks, and urban power grids.

Industrial & Commercial Utility & Grid

Rated Capacity: 31500 kVA
Rated Voltage Ratio: 66/10.5 kV
Connection Group: YNd11
Cooling Method: ONAN
Energy Efficiency Class: NX1
Standard：IEC 60076, GB/T 6451-2023

Product Details

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Product Model SZ22-31500/66-NX1

No-Load Loss ≤14.8 kW

Rated Capacity 31500 kVA

No-Load Current ≤0.35%

Phase 3-phase

Load Loss (75°C) ≤108 kW

Rated Voltage Ratio 66/10.5 kV

Short-Circuit Impedance 9.0%

HV Tapping Range ±8×1.25%

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

Rated Frequency 50 Hz

Noise (Sound Pressure Level) ≤60 dB(A)

Connection Group YNd11

Protection Degree IP54

Cooling Method ONAN(ONAF available upon request)

Standard IEC 60076, GB/T 6451-2023

Insulation Class A, LI325 AC140 / LI75 AC35

Energy Efficiency Class NX1

01.

Core advantages

Class 1 Energy Efficiency (NX1)

Complies with GB 20052-2024 Class 1 energy efficiency standard. No-load loss of 14 kW and load loss of 108.0 kW meet the highest efficiency limits for 66kV/31500kVA power transformers, significantly reducing long-term operating costs.

On-Load Tap Changer (OLTC)

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

High Reliability & Low Loss Design (S22 Level)

Optimized core and winding design, combined with a robust oil-immersed structure, ensures low loss, low partial discharge, low temperature rise, strong short-circuit withstand capability, 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

66kV Oil-Immersed Power Transformer Series – Full Specifications

66kV, 3-phase, 2-winding, oil-immersed, on-load tap-changer, power transformer, 6300-63000kVA
Model	Rated Capacity (kVA)	HV (kV)	HV Tapping Range	LV (kV)	Vector Group	No-Load Loss (kW)	Load Loss (75°C) (kW)	Impedance Voltage (%)
SZ22-6300/66-NX1	6300	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	4.4	30.8	9
SZ20-6300/66-NX2	6300	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	5.2	30.8	9
SZ18-6300/66-NX3	6300	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	6.4	32.5	9
SZ22-8000/66-NX1	8000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	5.3	36.5	9
SZ20-8000/66-NX2	8000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	6.2	36.5	9
SZ18-8000/66-NX3	8000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	7.7	38.5	9
SZ22-10000/66-NX1	10000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	6.2	43.0	9
SZ20-10000/66-NX2	10000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	7.3	43.0	9
SZ18-10000/66-NX3	10000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	9.0	45.4	9
SZ22-12500/66-NX1	12500	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	7.4	51.1	9
SZ20-12500/66-NX2	12500	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	8.7	51.1	9
SZ18-12500/66-NX3	12500	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	10.7	54.0	9
SZ22-16000/66-NX1	16000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	8.9	62.8	9
SZ20-16000/66-NX2	16000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	10.5	62.8	9
SZ18-16000/66-NX3	16000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	12.9	66.3	9
SZ22-20000/66-NX1	20000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	10.6	76.1	9
SZ20-20000/66-NX2	20000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	12.5	76.1	9
SZ18-20000/66-NX3	20000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	15.4	80.4	9
SZ22-25000/66-NX1	25000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	12.5	90.0	9
SZ20-25000/66-NX2	25000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	14.8	90.0	9
SZ18-25000/66-NX3	25000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	18.2	95.0	9
SZ22-31500/66-NX1	31500	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	14.8	108.0	9
SZ20-31500/66-NX2	31500	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	17.5	108.0	9
SZ18-31500/66-NX3	31500	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	21.5	114.0	9
SZ22-40000/66-NX1	40000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	17.7	126.9	9
SZ20-40000/66-NX2	40000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	20.9	126.9	9
SZ18-40000/66-NX3	40000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	25.8	134.0	9
SZ22-50000/66-NX1	50000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	20.9	150.3	10~12
SZ20-50000/66-NX2	50000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	24.7	150.3	10~12
SZ18-50000/66-NX3	50000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	30.4	158.7	10~12
SZ22-63000/66-NX1	63000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	24.7	178.2	10~12
SZ20-63000/66-NX2	63000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	29.2	178.2	10~12
SZ18-63000/66-NX3	63000	66，66，69	±8×1.25%	6.3，6.6，10.5	YNd11	35.9	188.1	10~12
Note： 1.±8×1.25% 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 6300kVA 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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SZ22-31500/66-NX1 Three-Phase Oil-Immersed On-Load Tap-Changer Power Transformer

66kV Oil-Immersed Power Transformer Series

SZ22-31500/66-NX1 Three-Phase Oil-Immersed On-Load Tap-Changer Power Transformer