Transformer Short-Circuit Impedance Tester Product Manual

I. Product Purpose and Features

       According to Article 15.2 of Document [2000] No. 589 issued by the State Power Corporation, "Twenty-Five Key Requirements for Preventing Major Accidents in Power Production": "For transformers with voltage levels of 110KV and above, low-voltage short-circuit impedance tests or frequency response analysis should be conducted before factory delivery and before commissioning to record original data." Article 15.6 stipulates: "After a transformer experiences a sudden short circuit in the vicinity, low-voltage short-circuit impedance tests or frequency response analysis should be performed to detect winding deformation, and the results should be compared with original records. The transformer can only be put into operation after confirming it is fault-free."

       Low-voltage short-circuit impedance measurement is a basic item in routine tests. By comparing the short-circuit impedance values measured before and after the transformer is subjected to short-circuit current impact, the degree of winding deformation can be preliminarily estimated based on the magnitude of change. The change in low-voltage short-circuit impedance after short-circuit current impact should not exceed 2%.

       The low-voltage short-circuit impedance test is a direct method to check whether the windings of a transformer in service have deformed after being subjected to short-circuit current impact or mechanical impact during transportation and installation. It is of great significance for determining whether the transformer can be put into operation, and it is also one of the bases for deciding whether the transformer needs to be disassembled for inspection.

       YTC3222 Transformer Short-Circuit Impedance Tester is developed by our company for measuring low-voltage short-circuit impedance of main transformers at 35KV level and above under field and laboratory conditions. The main features of this instrument are:

       The instrument is compact and lightweight.

       The instrument uses voltage and current synchronous AC sampling and digital signal processing technology internally, ensuring accurate measurement data.

       The instrument adopts single-phase measurement. After selecting the transformer connection, three measurements can automatically calculate the short-circuit impedance of each phase.

       The instrument has the function of automatically converting low current test results to rated current, suitable for field use.

       The instrument can simultaneously measure voltage, current, and power, and also measure the frequency of the applied power source.

       Built-in non-volatile memory allows long-term storage of measurement data, and the instrument comes with a built-in printer.

       Large-screen LCD display with all Chinese menus and operation prompts, making operation simple and intuitive. The LCD can be clearly displayed even under direct sunlight.

II. Main Technical Specifications and Operating Conditions

       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

       Voltage measurement range: AC  10V～600V

       Current measurement range: AC  0.5A～20A