Product Details

Oil-immersed High Voltage Testing Transformer

I. Overview

   Oil-immersed High Voltage Testing Transformer is the basic test equipment used for AC withstand voltage tests by power plants, power supply bureaus, and scientific research institutions.，It has passed the standards of the National Quality Supervision Bureau and is used to conduct insulation strength tests at specified voltages on various electrical products, electrical components, and insulating materials, to assess the insulation level of products, discover insulation defects in test objects, and measure the ability to withstand overvoltage.

II. Structure

The iron core of this series of products is a single-phase core type, laminated with high-quality cold-rolled grain-oriented silicon steel sheets, and fastened with steel as clamping pieces. The high-voltage coil is a cylindrical multi-layer tower type, wound with high-quality polyester enameled wire and high withstand voltage insulating materials. The low-voltage coil is on the outside, and the instrument coil is an independent winding, generally 100V. The shell is octagonal, and Satons test transformers above 10KVA are equipped with movable iron wheels. It has the characteristics of light weight, small size, easy movement, and superior performance.

III. Working Principle

1. AC, AC/DC Test Transformer:

Input the power frequency power supply into the operation box (or operation console), and adjust the voltage through the auto-transformer to input to the primary winding of the test transformer. According to the principle of electromagnetic induction, power frequency high voltage can be obtained on the secondary (high voltage) winding. This power frequency high voltage can be rectified by a high-voltage silicon stack and filtered by a capacitor to obtain DC high voltage, whose amplitude is 1.4 times the effective value of the power frequency high voltage. However, when using DC, the short-circuit rod should be pulled out, and when using AC, the short-circuit rod should be inserted.

2. Test Transformer with Taps:

In order to simultaneously resolve the contradiction between higher voltage and smaller current, and lower voltage and larger current, the high-voltage winding is divided into two windings: one with a larger current and the other with a smaller current. Then the two windings are connected in series and led out separately, as shown in the schematic diagram.

3. Cascade Test Transformer:

To obtain a test transformer with higher voltage, a cascade method can also be used to achieve higher voltage. Figure 2 shows the principle wiring diagram of a three-stage cascade test transformer. The capacity and voltage relationships of the three transformers satisfy: P1=2P2=3P3, U(total)=1U+2U+3U.

IV. Main Technical Indicators:

1. Rated capacity: 1～300KVA

2. Single unit rated output voltage:

(AC) 50, 100, 150, 200, 300KV

(DC) 70, 140, 210, 280KV

3. Rated input voltage: 200V, 400V

4. Transformation ratio: 500/1, 1000/1, 1500/1, 2000/1, 3000/1

5. Transformation ratio error: ≤±1.5%

6. Impedance voltage: <10%

Gas-filled High Voltage Test Transformer

I. Overview:

Gas-filled AC/DC Test Transformer

With the development of China's power industry, the voltage level requirements for test transformers are getting higher and higher, while traditional oil-immersed test transformers are increasingly unable to meet the requirements of on-site work in terms of volume and weight. Gas-filled test transformers reduce volume and weight, making it more convenient for customers to carry to the site for testing.

With the progress of basic scientific research in China and the application of new materials and new processes, the new medium sulfur hexafluoride gas has been pushed 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.

II. 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 the requirements of the <<JB3570－98>> standard.

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

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 pulling out the short-circuit rod, it 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.

III. Main Features:

1. This product is small in size and light in weight (40%-65% lighter than oil-immersed test transformers of the same level).

2. Clean, no oil stains, no maintenance required.

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

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

IV. Technical Parameters:

1. Voltage level: 10——600KV

2. Capacity range: 1——600KVA

3. No-load current: <7%

4. Impedance voltage: <8%

5. Partial discharge at rated voltage: <5PC



Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.