A Comparative Study of Dry Vacuum On-load Tap Changer and Traditional Tap Changer

I. Preface

With the development of the power system and the increasing demand for grid regulation, tap changers, as important supporting equipment for transformers, their performance directly affects the stability of power supply and the service life of equipment. Although traditional oil-immersed tap changers are widely used, they have problems such as complex maintenance and poor environmental protection. The dry-type Vacuum On-Load Tap Changer (V-OLTC) has gradually become an important choice for modern power systems due to its advantages such as Dry insulation and vacuum arc extinguishing. This article will conduct a systematic comparative analysis of dry vacuum on-load tap changers and traditional tap changers from aspects such as structure, performance, safety, maintenance and application scenarios.

Ii. Overview of Tap Changers

1. Traditional tap changer

Oil-immersed design: By using oil as the arc-extinguishing and insulating medium, it achieves voltage regulation under load.

Load operation capability: It can switch tap points when the transformer is under load.

High maintenance requirements: The oil needs to be replaced regularly, posing risks of oil leakage and contamination.

Large volume: Due to the influence of the fuel tank and cooling requirements, the equipment occupies a large area.

2. Dry vacuum on-load tap changer

Vacuum arc extinguishing technology: The tap changer switches in a vacuum environment, and the arc is quickly extinguished.

Dry insulation design: No oil required, environmentally friendly and safe, reducing the risk of fire and environmental pollution.

High-reliability contact system: The tap changer and contacts are wear-resistant and operate smoothly.

Intelligent control compatibility: It can be connected to an automatic voltage regulation system to achieve remote monitoring and intelligent voltage regulation.

Iii. Structural Comparison

Project: Traditional oil-immersed tap changer, dry vacuum on-load tap changer

Insulating medium: Insulating oil, air/epoxy resin

Arc extinguishing methods: arc extinguishing in oil, vacuum arc extinguishing

The equipment is relatively large in size and requires a compact fuel tank space. Without a fuel tank, space can be saved

The maintenance difficulty is high, requiring regular oil replacement and oil circuit cleaning. The dry structure is convenient for maintenance

There is a risk of oil leakage and pollution in terms of environmental protection. It is dry and oil-free, environmentally friendly and safe

The intelligent compatibility is relatively low, and it can be remotely monitored and automatically regulated for voltage

Analysis

The dry vacuum tap changer is more compact in structure, reducing the reliance on oil and cooling systems. It not only saves space but also lowers safety risks, and is suitable for the remote monitoring requirements of modern smart grids.

Iv. Performance Comparison

1. Load voltage regulation capability

Traditional tap changers rely on oil for arc extinguishing during operation under load, and their action stability is affected by the quality and temperature of the oil.

The dry vacuum tap changer uses vacuum arc extinguishing, with rapid and stable contact action and a faster response to load changes.

2. Impact of power quality

Traditional switches may generate transient voltage fluctuations and harmonics when switching tap contacts.

Dry vacuum switches switch smoothly, have less impact on grid voltage fluctuations and harmonics, and are conducive to improving power quality.

3. Adaptability to the environment

Oil-immersed tap changers are sensitive to environmental temperature and humidity. A humid or high-temperature environment may accelerate the deterioration of the oil.

The dry vacuum tap changer has a dry structure that is resistant to high temperatures and humidity, making it suitable for industrial and urban environments.

V. Safety Comparison

1. Fire and pollution risks

Oil-immersed switches have the risks of oil leakage and fire. Once leakage occurs, it may cause damage to equipment and the environment.

The dry vacuum switch is oil-free in design, eliminating the risks of fire and pollution, and offering higher safety.

2. Arc extinguishing safety

Traditional switches rely on oil for arc extinguishing, which takes a relatively long time and makes the contacts prone to damage.

Vacuum arc extinguishing is fast and reliable, reducing contact wear and extending the service life of equipment.

Vi. Maintenance and Lifespan Comparison

Project: Traditional oil-immersed tap changer, dry vacuum on-load tap changer

The maintenance cycle is short, requiring regular oil replacement and oil circuit cleaning. The dry structure simplifies maintenance

The complexity of daily maintenance varies

The service life is highly affected by the wear of the oil and the contacts. The contacts are wear-resistant and easy to maintain

Troubleshooting is complex. Professional handling is required for oil contamination or mechanical faults, while mechanical components and contacts are easy to inspect

Dry vacuum tap changers significantly reduce the complexity of daily maintenance, extend the service life of equipment, and enhance operational reliability.

Vii. Comparison of Application Scenarios

1. Industrial load

Dry vacuum switches have a fast response and can withstand load fluctuations, making them more suitable for industrial enterprises, especially precision manufacturing industries.

2. Urban power distribution

Oil-free design is environmentally friendly and safe, suitable for urban residential areas and commercial power distribution systems.

3. New energy access

The grid connection of photovoltaic and wind power causes voltage fluctuations. Dry vacuum switches can quickly adjust the voltage to ensure the stability of the power grid.

4. Smart grid

It can be integrated with automatic voltage regulation and remote monitoring systems to achieve intelligent operation and maintenance and improve the management efficiency of the power system.

Through the comparison of structure, performance, safety, maintenance and application scenarios, it can be seen that dry vacuum on-load tap changers have obvious advantages in modern power systems:

Dry insulation, oil-free and environmentally friendly, reducing the risk of fire and pollution.

Vacuum arc extinguishing technology ensures smooth voltage regulation under load and reduces the impact on power quality.

It is easy to maintain, has a long service life and reduces operation and maintenance costs.

It has high intelligent compatibility and can meet the demands of new energy and modern smart grids.

Although traditional oil-immersed tap changers still have mature reliability and cost advantages, in modern high-demand power systems, dry vacuum on-load tap changers are undoubtedly a safer, more efficient and environmentally friendly choice. In the future, with the upgrading of the power system and the development of green energy, dry vacuum tap changers will play an increasingly important role in industrial, urban power distribution and new energy access fields.