Transformer Winding Deformation Tester
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Transformer Winding Deformation Tester is an intelligent instrument specifically designed for testing the impedance characteristics of large and medium-sized transformers. Short-circuit damage to power transformers is a serious main equipment damage accident in the power grid. It is necessary to reduce the occurrence of transformer short-circuit damage accidents by detecting transformer winding deformation. ME 1094.5-2003 "Power Transformers - Part 5: Ability to Withstand Short Circuit" lists the detection of short-circuit reactance value as a required item to determine whether the transformer has withstood the short-circuit current impact, and points out that "observing possible changes in the measured reactance is particularly important".
It is developed by our company and is suitable for power transformers with a capacity above 2500kVA. Power transformers with a capacity smaller than the above specification can also refer to the standard for implementation. The instrument uses high-precision synchronous AC sampling of voltage and current, as well as digital signal processing techniques such as FFT, ensuring accurate and stable measurement data. The instrument adopts three-phase or single-phase measurement methods. It only requires short-circuiting the low-voltage side; the non-tested phases on the high-voltage side do not need to be short-circuited. After selecting the transformer connection, one measurement can automatically calculate the short-circuit impedance of each phase. The instrument has a function of automatically converting low current test results to rated current, suitable for on-site use. The instrument can synchronously measure voltage, current, power, and power frequency. It can automatically record test data, has a built-in non-volatile memory for long-term storage of measurement data, and comes with a high-speed thermal printer for on-site printing of test data. The instrument features a large-screen LCD display with all Chinese menus and operation prompts, making it simple and intuitive to operate.
Product Features:
• High test accuracy: the accuracy of basic parameters such as current and voltage is better than 0.1%.
• System stability and strong anti-interference capability: the system adopts software digital filtering and hardware anti-aliasing filtering anti-interference technology, which greatly improves the test stability and anti-interference capability compared to similar instruments.
• Calibration and verification: the instrument uses LEM's NORMA4000 for calibration, ensuring that all produced equipment can be traced for accuracy.
•Transformer Winding Deformation Tester has three independent voltage and three independent current input channels. The measurement channels use 16-bit high-resolution AD converters, and all channels sample synchronously, fundamentally ensuring the accuracy of power calculation. GDRB-I meets all transformer wiring measurement methods.
• It can accurately measure transformer impedance even under severely distorted voltage and current waveforms and low power factors.
• All test channels are completely isolated and independent, with automatic range adjustment.
• The ratios of external PT and CT for all input channels can be set separately. When the input voltage is less than 500V and the current is less than 50A, direct measurement is possible. The 320X240 resolution high-definition LCD screen can display multiple test parameters simultaneously.
Technical Parameters:
² Measurement accuracy: Voltage, Current: 0.2 class
Power: COSφ>0.1: 0.5 class; COSφ≤0.1: 1.0 class
Impedance: COSφ>0.1: 0.5 class; COSφ≤0.1: 1.0 class
² Voltage measurement range: AC 10V～600V
² Current measurement range: AC 0.5A～20A
² Operating temperature: -10℃～50℃
² Operating humidity: 0～80%
² Power supply: AC220V±10% 50Hz±1Hz
² Dimensions: 360mm×220mm×150mm
² Weight: 5Kg
Precautions:
a) The necessary conditions for transformer winding deformation are outlet short circuit, near-zone short circuit, or multiple overcurrent operations, or impact during transportation;
b) In the low-frequency part (tens of kHz), the frequency response curves generally overlap well; otherwise, poor test wiring contact should be suspected first;
c) Generally, for transformers of 35kV and below (including plant transformers), the frequency response characteristics may have poor consistency, so original data should be kept for comparison at the time of handover;
d) The measured frequency response curve is generally between +20~-80dB; if it exceeds this range, check whether the test circuit has poor contact or disconnection;
e) When testing delta-connected windings separately, the three-phase frequency response characteristics may not be consistent;
f) Balancing windings may cause inconsistent three-phase frequency response characteristics;
g) Severe winding deformation can affect the frequency response characteristics of adjacent windings;
h) Some small factories and on-site repaired transformers may have poor frequency response characteristics due to poor workmanship;
i) Some literature indicates that temperature affects frequency response characteristics;
j) Interleaved windings with transposed conductors may cause inconsistent frequency response characteristics;
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
