Dual Canopy Mechanic Electrical Engineering Co., Ltd. is one of the leading manufacturers and suppliers of Turn Ratio Testing in China. Please feel free to wholesale discount products for sale here and get quotation from our factory. Customized orders are welcome.
What is Turn Ratio Testing?
Turn Ratio Testing (TTR Tester) is a specialized instrument used to measure the turns ratio, ratio error, phase angle (phase angle/polarity), and excitation current of transformers and instrument transformers. By accurately measuring the ratio of the primary and secondary voltages, it can verify whether the transformer winding turns ratio meets the nameplate and design requirements, determine whether there are problems such as inter-turn short circuits, winding wiring errors, and poor tap changer contact, and provide quantitative basis for handover acceptance, condition assessment, and fault diagnosis.
What are the features of Turn Ratio Testing?
1. The instrument uses a three-phase precision inverter power supply instead of a single-phase mains power supply as the measurement voltage, eliminating the harmonic influence of the mains voltage during measurement, and the measurement is more accurate. When the working power supply is a generator, there is no effect.
2. The three-phase output voltage is used to increase the test speed, and the phase angle can be measured, and the transformer with a neutral point can also be measured, and the transformer wiring group 0-11 can be automatically identified.
3. It is applicable to a wide range of transformers, especially for the measurement of Z-type transformers, rectifier transformers, grounding transformers, electric furnace transformers, phase-shift transformers, etc., with the most comprehensive measurement parameters.
What are the specific parameters?
1. Test range: 0.9~10000
2. Measurement accuracy:
±0.1%+2 digits (0.9-500)
±0.2%+2 digits (501-2000)
±0.5%+2 digits (2001-10000)
3. Angle accuracy: ±0.2°
4. Output voltage: automatically adjusted according to load
5. Resolution: minimum 0.0001 angle -- 0.01°
6. Test line length: 13 meters as standard, length can be customized
Where are they used?
Power transformers (distribution transformers/power transformers/autotransformers)
Current transformers (CT): Turns ratio and polarity verification
Voltage transformers (PT/VT): Turns ratio and phase verification
Instrument transformers: Turns ratio verification for metering and protection applications
Special transformers: Rectifier transformers, traction transformers, phase-shifting transformers, etc. (supported by model)
What are the precautions for use?
The transformer must be de-energized and isolated. Before the turns ratio test, ensure the transformer is completely disconnected from the operating system and implement all safety measures, including de-energizing, voltage testing, and grounding.
Short-circuit wires and grounding wires must be completely removed. Before testing, confirm that there are no short-circuit wires on the winding under test; otherwise, it may damage the instrument or lead to incorrect results.
Tap switch positions must be clearly recorded. Record the current tap position before each test to ensure consistency with historical data and avoid misjudgments due to tap position differences.
Carefully verify the polarity of the three-phase connections. During three-phase testing, the polarity of each phase connection must be correct; otherwise, systematic errors will occur in the phase angle calculation.
The test voltage must not exceed the withstand voltage capacity of the winding under test. Some low-voltage small transformers have lower rated secondary voltages; ensure the test voltage is within the allowable range.
FAQ
Q1; What types of transformers can the Turn Ratio Tester test?
A: It is suitable for power transformers, distribution transformers, autotransformers, CT/PT transformers, etc. The specific turns ratio range depends on the model and range.
Q2; What turns ratio error is considered out of tolerance?
A: According to IEC/GB standards, different accuracy classes of transformers have different allowable turns ratio errors. Generally, distribution transformers are required to be within ±0.5%; metrology classes are more stringent, and judgment should be made in conjunction with the nameplate and standards.
Q3; What does a high excitation current indicate?
A: It may indicate core damage, abnormal magnetic circuit, or inter-turn short circuit; it is recommended to combine no-load loss, SFRA, and DC resistance for comprehensive judgment.
Hot Tags: Turn Ratio Testing, China Turn Ratio Testing manufacturers, suppliers, factory, power testing equipment, 3 phase transformer turns ratio analyser, power turns ratio analyser, power turns ratio meter, Transformer turns ratio testing
