The temperature monitoring system for 35kV SFZ22 Series Oil-immersed Transformers usually consists of multiple sensors, data acquisition devices, communication modules, and display control devices. Sensors are installed in key parts of transformers, such as oil tanks, windings, etc., to detect the temperature in these areas.

The data obtained by sensors will be processed and transmitted through data collection devices, and then transmitted to remote monitoring systems or local display devices. The communication module is used to ensure data transmission and system linkage between different devices, ensuring real-time updates of monitoring data.

A significant function of the temperature monitoring system for power transformer is temperature anomaly warning. When the temperature of a certain part of the 35KV oil immersed power transformer exceeds the set security threshold, the system will automatically issue an alarm signal to remind the operator to take timely measures to avoid equipment overheating and other malfunctions or damages. Through this system, operators can remotely view the temperature status of the equipment, perform real-time scheduling and adjustment, and ensure the normal operation of the equipment.

35kV SFZ22 Series oil-immersed transformers: Technical Overview and Applications

Introduction

35kV SFZ22 series oil-immersed transformers are widely used in power distribution systems due to their reliability, efficiency, and robust design. These transformers are designed to step down high-voltage electricity (35kV) to lower voltages suitable for industrial, commercial, and residential applications. The SFZ22 series incorporates advanced insulation materials, efficient cooling systems, and durable construction to ensure long-term performance in demanding environments.

This article provides a detailed technical overview of 35kV SFZ22 oil-immersed transformers, covering their design features, operational principles, key specifications, and typical applications.

1. Design and Construction Features

1.1 Core and Winding Structure

The SFZ22 series transformers utilize a high-quality silicon steel core to minimize energy losses and improve magnetic flux distribution. The core is designed with a step-lap construction to reduce no-load losses and noise levels.

The windings are made of copper or aluminum conductors, depending on the specific model and application requirements. Copper windings offer lower resistance and better efficiency, while aluminum windings provide a cost-effective alternative. The windings are insulated with high-temperature-resistant materials to withstand thermal stresses during operation.

1.2 Insulation and Cooling System

These transformers use mineral oil as both an insulating and cooling medium. The oil circulates naturally (ONAN) or with forced cooling (ONAF/OFAF) to dissipate heat generated during operation. The SFZ22 series also features an advanced oil preservation system, including a conservator tank with a breather to prevent moisture ingress.

1.3 Tap Changer Mechanism

A notable feature of the SFZ22 series is its on-load tap changer (OLTC), which allows voltage adjustment without interrupting power supply. This ensures stable voltage output under varying load conditions, making these transformers ideal for grid applications where voltage fluctuations are common.

1.4 Tank and Protection Systems

The transformer tank is constructed from corrosion-resistant steel and is designed to withstand mechanical stress and environmental factors. Additional protective features include:

Buchholz relay – Detects internal faults and gas accumulation.

Pressure relief device – Prevents tank rupture during excessive internal pressure.

Temperature monitoring – Includes oil and winding temperature indicators for real-time thermal management.

2. Key Technical Specifications

The 35kV SFZ22 series transformers are available in various power ratings, typically ranging from 1,000 kVA to 20,000 kVA. Key specifications include:

Rated Voltage: Primary – 35kV, Secondary – 6.3kV, 10.5kV, or other customized levels.

Frequency: 50Hz or 60Hz (depending on regional standards).

Impedance Voltage: 6.5% to 10.5% (adjustable based on application).

No-load Losses: Optimized to meet international efficiency standards (e.g., IEC 60076).

Load Losses: Minimized through high-quality conductor materials and design optimization.

Cooling Methods: ONAN (Oil Natural Air Natural), ONAF (Oil Natural Air Forced), or OFAF (Oil Forced Air Forced).

Sound Level: Typically below 65 dB at rated load.

3. Performance and Efficiency

The SFZ22 series is designed for high energy efficiency, meeting or exceeding industry standards such as IEC, ANSI, and GB. Key performance characteristics include:

Low No-load Losses: Achieved through high-grade core materials and optimized magnetic circuits.

High Overload Capacity: Capable of handling short-term overloads without performance degradation.

Minimal Maintenance Requirements: The robust design and high-quality materials reduce the need for frequent servicing.

4. Applications of 35kV SFZ22 Oil-immersed Transformers

These transformers are widely used in:

4.1 Power Distribution Networks

Step-down substations in urban and rural power grids.

Industrial parks requiring stable medium-voltage power distribution.

4.2 Renewable Energy Integration

Wind and solar farms where voltage transformation is needed before grid connection.

4.3 Mining and Heavy Industries

High-demand environments requiring durable and reliable power supply.

4.4 Commercial and Infrastructure Projects

Large-scale buildings, hospitals, and data centers with critical power needs.

5. Installation and Maintenance Guidelines

5.1 Installation Requirements

Site Preparation: A stable, well-ventilated foundation with proper drainage.

Safety Clearances: Adequate spacing for cooling and maintenance access.

Earthing System: Proper grounding to prevent electrical hazards.

5.2 Routine Maintenance

Oil Testing: Regular dielectric strength and moisture content checks.

Winding Inspection: Thermal imaging to detect hotspots.

Tap Changer Servicing: Lubrication and contact resistance measurements.

6. Advantages Over dry-type transformers

While Dry-type Transformers are used in certain applications, oil-immersed transformers like the SFZ22 series offer:

Higher Efficiency: Better heat dissipation and overload capacity.

Longer Lifespan: Oil insulation reduces thermal degradation.

Cost-Effectiveness: Lower initial and operational costs for high-power applications.

The 35kV SFZ22 series oil-immersed transformers are a reliable and efficient solution for medium-voltage power distribution. Their advanced design, robust construction, and adaptability to various applications make them a preferred choice in the energy sector. Proper installation and maintenance ensure optimal performance and longevity, supporting stable and efficient power transmission across multiple industries.

For engineers and project planners, selecting the right transformer involves evaluating load requirements, environmental conditions, and efficiency standards—factors where the SFZ22 series excels.