Inflatable Test Transformer

Test transformer is essential testing equipment for power equipment inspection and preventive tests. With the development of China's power industry, the voltage level requirements for test transformers are increasingly higher, while traditional oil-immersed test transformers are increasingly unable to meet on-site work requirements in terms of volume, weight, and performance.

Chinese Name

Inflatable Test Transformer

English Name

The inflatable test transformer

Nature

New insulating medium

Advantages

Small size, light weight, beautiful appearance

With the advancement of basic scientific research in China and the application of new materials and new processes, the new medium sulfur hexafluoride gas has been introduced into the application field of power equipment. Due to the excellent insulation performance, arc extinguishing performance, and non-flammability of sulfur hexafluoride gas, it has been widely used as a new insulating medium, leading to the creation of the inflatable test transformer.

After years of efforts, the inflatable lightweight test transformer has been successfully developed. Compared with traditional oil-immersed lightweight test transformers, this series of products weighs 20%-60% less (depending on voltage and capacity levels), and has no oil pollution. The voltage level of a single test transformer can reach 300KV. Due to the adoption of new production processes, the technical performance of the products has been greatly improved, making them particularly suitable for on-site work and frequent mobile working conditions.

Introduction

The high-voltage test transformer is produced based on the Ministry of Machinery and Electronics' "Test Transformer" standard, with extensive improvements on the original similar products. The AC/DC high-voltage test transformer is a new type of product produced based on the YD series test transformer and improved according to the national standard "JB∕T 9641-1999". This series of products features small size, light weight, compact structure, complete functions, strong universality, and convenient use. It is particularly suitable for insulation strength tests under power frequency or DC high voltage for various high-voltage electrical equipment, electrical components, and insulating materials in power systems, industrial and mining enterprises, and scientific research departments. It is an indispensable important equipment in high-voltage testing.

Structure

1. The design concept, material selection, and process flow of the YDQ series products are all new. Therefore, they not only have small size, light weight, and beautiful appearance, but also all technical indicators meet international high-standard requirements.

The YDQ series products use high-quality cold-rolled DQ-151 oriented silicon steel sheets stacked into a multi-stage cylindrical frame-shaped iron core, and use QZ type wires to continuously wind the high-voltage tower-type coil directly on a specially made high-strength insulating cylinder. The shell is of suitable size and filled with SF6 gas inside.

2. The difference between YDQ (JZ) products and YDQ products is that the high-voltage rectifier silicon stack is cleverly installed inside the high-voltage bushing, and by inserting or extracting the short-circuit rod, the YDQ can be switched between power frequency high-voltage AC output and high-voltage DC output.

3. The difference between YDQ (C) products and YDQ products lies in the internal structure of the bushing and the structure of the high-voltage coil.

4. YDQW products are based on ordinary transformers, with improved processes and technology, adopting different insulation structures, and utilizing the arc extinguishing capability of SF6 gas itself, so that under high voltage, the transformer basically has no partial discharge. Thus, when using this transformer as a high-voltage power source for partial discharge tests of electrical equipment, it can be combined with high-precision



Working Principle

Power input passes through an operation box with overcurrent automatic trip and zero-position interlock device to prevent sudden voltage application, and the voltage is regulated by an auto-transformer and input to the primary winding of the YDQ test transformer. According to the principle of electromagnetic induction, a voltage amplitude - power frequency high voltage - equal to the multiple of the turns ratio between the secondary (high-voltage) winding and the primary winding can be obtained. This power frequency high voltage can be rectified by a high-voltage silicon stack and filtered by a voltage-stabilizing capacitor to obtain DC high voltage, whose amplitude is twice the effective value of the power frequency high voltage.

 

Technical Parameters

>Voltage level: 10——600KV

>Capacity range: 1——600KVA

>No-load current: <7%

>Impedance voltage: <8%

>Partial discharge at rated voltage: <5PC



Model Meaning

Rated output voltage KV

Rated capacity KVA

JZ AC/DC, C cascade

Inflatable Q

Single phase D

Characteristics

1. Clean, no oil contamination, no maintenance required;

2. Not affected by harsh weather conditions, can be tested immediately after on-site handling without needing to rest;

3. Insulation strength is significantly higher than oil-immersed test transformers, with minimal corona.