Short Circuit Impedance Tester

I. Overview

Short-circuit impedance is a crucial parameter for transformers. The short-circuit impedance method is a traditional approach to assessing winding deformation. According to GB1094.5-2008 and IEC60076-5:2006 regulations, the variation in short-circuit reactance is the sole criterion for determining whether a transformer's winding is deformed. Measuring transformer winding parameters is also an effective means of assessing the manufacturing quality of transformers and determining the impact of transportation on the transformer winding.

Low-voltage short-circuit impedance testing is a direct method for determining whether a transformer's windings are deformed after being subjected to short-circuit current impacts during operation, or after mechanical force impacts during transportation and installation. It is of great significance in judging whether the transformer can be put into operation and is one of the bases for determining whether a disassembly inspection is required.

The Transformer Short Circuit Impedance Tester is designed for low voltage load impedance testing during the production, major overhaul, pre-test, and handover tests of electrical transformers (single-phase or three-phase). It is a fundamental item in the conventional testing program. The principle involves on-site testing of the transformer's short-circuit impedance (%), comparing it with the rated or factory value. This process can detect defects such as winding displacement and deformation caused by severe fault currents during transportation, installation, and operation after the factory test.

Our independently developed Transformer Short Circuit Impedance Tester is designed for low voltage short circuit impedance measurements on 35KV and above main transformers under field and laboratory conditions. The instrument boasts a sophisticated design and superior performance, utilizing a new single-chip microcomputer testing technology and digital signal processing technology for accurate measurement data. It features a 7-inch touch color LCD display with Chinese operating menus for convenient touch operation. Equipped with a thermal printer and storage capabilities, it facilitates data printing and storage, allowing required data to be transferred to a computer via USB. The compact size of the instrument makes it easy to carry and use on-site. With the input of parameters, the instrument can perform single and three-phase tests and automatically calculate the transformer impedance error percentage, providing a very intuitive test result. It is a rapid on-site testing instrument for determining whether there is winding deformation in transformers.

Section II: Safety Measures

Be sure to read this manual thoroughly before using the instrument, especially adhere to the warnings and tips.

2. This instrument is suitable for both indoor and outdoor use, but should be kept away from areas prone to rain, corrosive gases, and similar conditions. The instrument should be protected from excessive vibration to prevent any impact on the test data.

3. Maintenance, care, and adjustment of the instrument should be performed by professionals; unauthorized disassembly is prohibited.

4. Ensure the selected menu items match the actual test items and wiring.

During testing, the removal of the mobile test clips and the shutdown of power supply lines is strictly prohibited.

III. Performance Features

The instrument uses a 220V AC low-voltage power supply and applies current to the AB, BC, and CA windings of single-phase and three-phase transformers through manual and automatic modes. In addition to measuring the error percentage between the transformer's short-circuit impedance and rated impedance, it also allows for the measurement of transformer impedance, reactance, resistance, inductance, and other values for easy data comparison, with test results being highly intuitive.

2. The instrument can perform single-phase testing as well as three-phase testing; it can be manually tested or automatically tested.

3. Single-cable connection, automatically completes three-phase testing without the need for reverse connection of test wires.

4. Measurement of the tested item can be conducted without an external voltage regulator.

5. The instrument not only displays the percentage of impedance error, but also shows values such as applied voltage, applied current, measured power, short-circuit impedance, short-circuit reactance, winding inductance, and short-circuit impedance voltage.

6. Zero-sequence impedance is applicable to transformers with star connection on the high voltage side with a neutral point. The instrument can simultaneously measure zero-sequence impedance, zero-sequence reactance, zero-sequence resistance, and zero-sequence inductance.

The instrument can be powered by either internal or external power sources.

The instrument features a 7-inch color touch LCD screen with Chinese operating menus, offering a more convenient touch operation. It is also equipped with a mini printer for real-time data printing.

9. Equipped with an RS232 interface, test data can be transmitted to the backend.

10. The device can store up to 100 test records, with data storage indexed by the test save time.

11. Equipped with a USB interface, test data can be saved to a USB flash drive.

The instrument features an integrated clock function, which allows for self-adjustment of the time.