I. Overview

1.1 Product Overview

The HZBB-10B transformer turns ratio tester is a fully automatic tester integrating turns ratio, voltage ratio, vector relationship, connection group, polarity, tap position, and excitation current testing functions . The tester features a 7- inch high-definition color touchscreen with a user-friendly interface and simple operation , allowing for full touchscreen operation without a keyboard . The instrument can be controlled entirely via a dedicated APP, and test data is stored and uploaded for easy retrieval. The tester overcomes the shortcomings of traditional turns ratio bridge tests by employing a three-phase precision inverter power supply, resulting in fast testing and high accuracy.

1.2 Main features

▪ It has a blind test function. When the connection group of a three-phase transformer is unknown, it can correctly measure the transformer's turns ratio, the phase relationship between the primary and secondary phases, and the group number, and list the possible connection groups of the transformer.

▪ It has the function of testing the ratio and polarity of CT and PT current transformers.

▪ It has a neutral (N) line measurement function, which can determine whether the neutral line is properly led out for transformers with a neutral (N) line.

It can automatically measure the turns ratio of three-phase and single-phase transformers and calculate the turns ratio error; it can measure the transformer connection group number and display the primary and secondary wiring vector diagrams, which are intuitive, clear, and concise.

▪ Features high and low voltage reverse connection protection, transformer inter-turn short circuit protection, tap changer incomplete opening/closing protection, and output full short circuit protection, increasing instrument stability.

▪ After inputting the rated parameters, it can automatically measure the transformer turns ratio, error value, and tap position. Especially for taps with asymmetrical taps, it can accurately measure the exact position of the transformer taps. It can measure up to 99 tap positions.

▪ Added tap sequence settings to accommodate transformers with high voltage at high tap positions and low voltage at high tap positions.

▪ Add low-voltage side tap settings to accommodate transformers with taps on the low-voltage side.

▪ The instrument has a printer output, a USB flash drive interface, and can also be equipped with an RS232 interface for easy paperless office work.

It can store 1000 sets of measurement results, and can export .csv files to a USB flash drive, which can be opened in Excel spreadsheets.

1.3 Panel Description

1. Grounding post: Before conducting any tests, ensure the grounding post is properly grounded to prevent the risk of electric shock.

2. Power socket and switch: The power input port of the tester , used to turn the tester's power supply on or off.

3. High-voltage side terminals: Yellow, green, red , and black terminals, which should be connected to the A, B, C , and N terminals on the high-voltage side of the transformer under test .

4. Low-voltage side terminals: Yellow, green, red , and black terminals, which should be connected to terminals a, b, c , and n on the low-voltage side of the transformer under test . 

5. RS232 communication interface: computer communication interface.

6. Printer: Print the test results.

7. USB: Insert the USB flash drive to export data.

8. Display screen: 7-inch high-definition color touch screen LCD, digitally adjustable backlight, displays operation menu and test results.

II. Precautions

2.1 Instructions for Use

Only qualified trained personnel may operate the testing instrument. Operators must read and understand this instruction manual before operating the instrument. Operators must comply with the instructions in this manual and observe all precautions during the use of the testing instrument. If the equipment malfunctions, immediately disconnect the power and return it to our company for repair.

2.3 Safety Precautions

▪ This tester is intended for use only as described in this manual. Please strictly adhere to the information provided in the "Precautions" section.

▪ All terminals of testing equipment and high-voltage electrical equipment systems pose a potential risk of electric shock. Use all practical safety precautions to avoid contact with live parts of the equipment and related circuitry.

• Use appropriate barriers, roadblocks, or warnings to ensure that personnel not directly involved in the work stay away from testing activities.

• Never connect the tester to a powered device.

• Do not use in rainy or explosive environments.

• Before conducting any tests , the grounding post on the tester panel should be reliably grounded to prevent any hazards.

2.4 Precautions for use

Before testing, please carefully check the wiring to ensure there are no reverse connections, short circuits, or incorrect connections.

▪ For measurements of Y/y, Y/d, D/y, D/z, and Y/z, a neutral point connection is not required. For measurements of single-phase transformers and PT/ CT, use the yellow and red terminals and test clips.

▪ For transformers with multiple tap points, the input of tap spacing , rated taps, tap sequence , rated high voltage, and rated low voltage is to enable the test results to automatically calculate the error value and the tap position of the tap changer. Once the rated data is input, the error value of each tap point and which tap point it is can be automatically calculated when testing each tap point without having to make any further changes to the input parameters.

▪ If the number of short-circuit turns is small, the fault may not be detected by turns ratio testing alone. The problem can be analyzed by the excitation current results .

2.5 Operating power supply precautions

Before connecting the power supply, ensure that the tester's operating voltage matches the input voltage. The tester's control circuit is equipped with a fuse.

Fuse protection. The fuse is located in the power socket and switch module, mounted on the tester panel, and can be replaced by the operator.

----------------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------------

III. Technical Parameters

Test range: Turns ratio -- 0.9 ~ 40000 ; Current -- 0 ~ 2000mA; Angle -- 0 ~ 360°

Ratio accuracy:

Current accuracy: ±(1% of reading + 0.5 mA)

Angle accuracy: ±0.2°

Output voltage: 160V , 80V , 40V, 12V selectable.

Resolution: Ratio -- Minimum 0.0001, Current -- 0.001mA, Angle -- 0.01°

Operating power supply: 100-240VAC 50/60Hz, maximum power 60W

Ambient temperature: -20 ℃ ～ 50 ℃

Relative humidity: ≤ 95 %, no condensation

External dimensions: Main unit: 360*290*170(mm); Cable box: 360*290*170(mm)