The transformer capacity characteristic tester is a high-performance portable instrument that integrates multiple testing functions. This instrument is mainly used to measure the actual capacity, no-load loss, load loss, and other key parameters of distribution transformers on-site quickly and accurately without external power supply (power outage). It can then determine the performance status and energy efficiency level of the transformer and verify the authenticity of its nameplate capacity.
Working principle
The core principle of the instrument’s operation is based on the equivalent circuit model of the transformer and the low-voltage short-circuit method. It is specifically divided into the capacity determination principle and the loss measurement principle.
Capacity determination principle
Apply a lower test voltage to the high-voltage side (or low-voltage side) of the transformer and short-circuit the low-voltage side at the same time. Measure the short-circuit loss at this time. Pk
Short-circuit current Ik
Parameters. According to the transformer similarity law, the load loss is proportional to the square of the rated current. The instrument will compare the measured data with the typical impedance parameters of transformers of various capacities in the built-in database, thereby intelligently matching the closest actual capacity.
Loss measurement principle
No-load loss: Apply the rated voltage at the low-voltage side of the transformer at the rated frequency, keep the high-voltage side open-circuited, and directly measure the input power. This power is the no-load loss.
Load loss: Apply the rated current (or reduced current) at the high-voltage side of the transformer, keep the low-voltage side short-circuited, measure the input power at this time, and convert it to the rated condition to obtain the load loss.
Main application scenarios
Transformer acceptance: Conduct performance acceptance work before the installation of newly purchased transformers.
Preventive testing: Regularly detect the health status of operating transformers, promptly identify potential faults.
Electricity inspection: Inspect whether there are “capacity shortfall” (actual capacity less than the nameplate capacity) related issues or “capacity surplus” causing overload risks in transformers.
Factory testing and quality control: Conduct performance tests on transformer products before leaving the factory to ensure product quality.
Fault diagnosis and post-repair tests: Conduct diagnosis when a transformer fails and carry out performance verification tests after the repair is completed.
Energy efficiency assessment: Provide accurate data basis for transformer energy-saving renovations and the elimination of high-energy-consuming equipment.
Post time: Jan-12-2026