CT volt ampere ratio polarity comprehensive tester for transformers

The core function of the transformer volt ampere ratio polarity comprehensive tester is to determine whether the transformer meets the operating standards through integrated testing, and to promptly detect potential defects such as inter turn short circuits, iron core saturation, and wiring errors.

1、 Core Definition and Technical Principles

The volt ampere characteristics of a transformer reflect the magnetization performance of the iron core, the transformation ratio determines the measurement accuracy, and the polarity is related to the correct operation of the relay protection system. Together, the three constitute the core evaluation system of transformer performance. The core function of the transformer volt ampere ratio polarity comprehensive tester is to determine whether the transformer meets the operating standards through integrated testing, and to promptly detect potential defects such as inter turn short circuits, iron core saturation, and wiring errors.

Its technical principle integrates a multi module collaborative working mechanism: firstly, the built-in high-precision power module provides adjustable voltage of 0-1000V and adjustable current of 0-600A, meeting the testing requirements of transformers of different specifications; Secondly, the output signal of the transformer is synchronously collected through a 24 bit high-precision AD sampling chip, and combined with FIR digital filtering technology to eliminate on-site electromagnetic interference; Finally, the embedded system runs specialized algorithms to complete data processing, curve drawing, and error calculation. For example, in volt ampere characteristic testing, the instrument applies a gradient voltage from the secondary side of the transformer, records the corresponding excitation current, automatically generates a U-I characteristic curve, and determines the quality of the iron core through inflection point analysis; The transformation ratio test adopts the voltage comparison method, which calculates the actual transformation ratio by the voltage ratio between the primary and secondary sides, avoiding the drawbacks of traditional current methods that require a large current source. Some models also have automatic demagnetization function. After testing, the iron core demagnetization is achieved by gradually reducing the voltage to ensure the accuracy of the transformer's subsequent operation.

2、 Core functions and significant advantages

The function of the transformer volt ampere ratio polarity comprehensive tester covers the entire process of transformer detection, with outstanding core capabilities and practicality. In terms of basic testing, the volt ampere characteristic test can automatically boost to 1000V, record multiple sets of voltage and current data, and generate standard characteristic curves, automatically identifying the inflection point voltage and current of the curve; Variable ratio testing supports multiple specifications such as CT (5A/1A) and PT (100V/√ 3, etc.), with a measurement ratio range of up to 999.9K:5/1 and an error control within ± 0.5%; Polarity testing uses sound and light alarms to visually indicate the correctness of wiring, avoiding protection misoperation caused by polarity reversal.

Compared to traditional testing methods, its advantages are extremely significant: firstly, it has a high degree of integration, comes with a 3KVA power module, and does not require external auxiliary equipment such as voltage regulators and current boosters. A single machine can complete all tests; Secondly, it has a high level of intelligence, with built-in algorithms that can automatically calculate 5% and 10% error curves and generate test reports that meet standards; Thirdly, it is easy to operate and adopts a graphical interface. Only the transformer model and rated parameters need to be entered, and the test can be completed with one click, greatly reducing the skill requirements for operators; Fourthly, it has strong anti-interference ability. The power supply and sampling circuit have been designed with electromagnetic compatibility, and can work stably in a wide temperature environment of -10 ℃ -55 ℃ and complex electromagnetic scenes.

3、 Key technical parameters

The technical parameters directly determine the adaptability range and testing accuracy of the transformer volt ampere ratio polarity comprehensive tester, and the mainstream product parameters have formed a standardized system. In terms of power output, CT volt ampere testing can provide a voltage of 0-1000V and a current of 0-20A, PT volt ampere testing can output a voltage of 0-330V, and the output current during variable ratio testing can reach 600A, meeting the requirements of transformers of various voltage levels from 10kV to 220kV. In terms of measurement accuracy, the voltage and current measurement accuracy both reach level 0.5, and the measurement error of the transformation ratio is less than ± 0.5%, ensuring the accuracy of the test data.

In terms of data processing and storage, the instrument is equipped with a large LCD screen that can display characteristic curves and test data in real time. The built-in storage module can store thousands of sets of test records and supports USB interface data export and on-site printing. Excellent performance in environmental adaptability parameters, the working power supply supports AC220V ± 20% wide voltage input, adapts to unstable power supply environments on site, and can still work normally under relative humidity conditions of ≤ 85%. Some outdoor models also have dust-proof and waterproof designs.

4、 Main application scenarios

The application of this instrument has penetrated the entire industry chain of the power system and become an important detection equipment. In the quality inspection process of transformer production, the manufacturer uses it to conduct batch testing on the factory products, compares the volt ampere curve to investigate the problem of inter turn short circuit, and conducts ratio testing to ensure that the measurement accuracy meets the requirements of the nameplate, thus controlling product quality from the source. In the field of power grid operation and maintenance, during daily inspections of substations, operation and maintenance personnel use this instrument to periodically detect transformers, such as comparing the volt ampere characteristic curve with historical data to determine whether the iron core is aging; During fault repair, quickly complete polarity testing to avoid delayed repair progress due to wiring errors.