I. Product Classification
The power frequency transformer comprehensive tester can be classified in multiple dimensions to clearly define the usage requirements.
According to the power frequency frequency, it is mainly divided into power frequency testers and high-frequency testers. The power frequency tester can output a true sine wave consistent with the grid frequency, which can truly simulate the operating state of the transformer.
According to the test voltage, it can be classified into low-voltage equipment, high-voltage equipment, and ultra-high-voltage equipment. The selection mainly depends on the voltage level of the tested transformer. The difference is reflected in the different maximum output voltages of the instrument.
According to the product form, portable equipment has a small size and light weight. Some equipment can have a weight controlled within 12 to 18 kilograms, which is suitable for on-site use.
According to the functional integration degree, the multi-functional comprehensive tester is the current mainstream product. One device can complete multiple tests such as transformation ratio,伏安特性， etc.， and has higher efficiency than single-function equipment.
II. Application Scope
The power frequency transformer comprehensive tester has a wide range of applications， covering the entire process of transformer production， operation， operation and maintenance inspection.
The applicable objects include current transformers and voltage transformers. The current transformers include protection CT， metering CT， as well as special structure CT such as bushing CT， GIS internal CT， etc.； voltage transformers are mainly for electromagnetic voltage transformers.
III. Main Test Items
Excitation characteristic test： This is the core test to verify the performance of protection CT. It can automatically draw curves and calculate the turning point voltage and current.
Transformation ratio and polarity test： Used to verify the transformation ratio of the transformer and the connection direction of the winding.
10% or 5% error curve calculation： Used to determine whether the protection CT can meet the reliability requirements of the protection device in the short-circuit situation.
Winding DC resistance test： Checks the welding quality and contact condition of the winding.
Secondary load test： Measures the actual load of the secondary circuit to determine whether it is within the rated capacity of the transformer.
Ratio difference and phase difference test： Evaluates the metering or measurement accuracy of the transformer.
Power frequency AC withstand voltage test： Conducts insulation strength assessment on the secondary winding of the transformer.
Demagnetization： Eliminates the residual magnetism of the iron core， restoring the normal performance of the transformer.
IV. Core Principles and Steps for Selection
Selection is based on actual needs， matching the tested object and technical requirements. It can be carried out in the following four steps：
Step 1： Clearly define the tested object and test requirements
Determine the type of transformer， clarify whether it is mainly CT testing， PT testing， or both， and whether it is necessary to test special transformers such as bushing CT， TP type transient CT， etc.
Clarify the core test items. If used for protection CT acceptance， the excitation characteristic and 10% error curve are the core functions； if used for关口 metering， the ratio difference and phase difference test accuracy is particularly crucial.
At the same time， record the key electrical parameters of the transformer， including the larger rated current， voltage， accuracy level (such as 0.2S， 5P20)， rated capacity， etc.， to provide a basis for instrument range selection.
Step 2： Match key performance indicators
Output voltage and current are the core hard indicators. During excitation testing， the larger output voltage of the instrument needs to be higher than the turning point voltage of the transformer. The turning point voltage of protection-level CT can reach hundreds to thousands of volts， and output voltage models of 1000 volts， 1200 volts， 2500 volts， etc. can be selected.
During transformation ratio testing， the larger output current of the instrument needs to cover the rated current of the tested CT or generate sufficient test signals. Common large current output specifications are 400 amperes， 600 amperes， 1000 amperes， etc.
The test accuracy needs to comply with relevant standards. The equipment accuracy usually needs to be two to three levels higher than the accuracy level of the tested transformer. In precise measurement scenarios， it is recommended to select models with an accuracy of no more than 0.05%. In terms of functional integration, for on-site use, a multi-functional comprehensive tester is preferred. For specialized research in the laboratory, equipment with specific functions can be selected.
Step 3: Consider usage scenarios and convenience
For on-site use, the weight and volume of the equipment need to be given priority consideration. The weight of mainstream portable instruments is approximately 18 to 23 kilograms, and lightweight products can be as low as 12 kilograms.
In terms of power supply adaptability, the on-site environment is complex, so equipment that supports single-phase AC220 volts input is preferred. Some high-end models can be equipped with built-in batteries, suitable for scenarios without power.
The operation interface and data management are also important. A large screen that is visible in sunlight, a rotating mouse or a touch screen can enhance the operation experience. At the same time, the data storage capacity of the equipment, USB communication function, and whether it supports generating Word and Excel format reports should be examined, to facilitate later data organization.
Step 4: Examine technology and service guarantees
Choose products with mature technology and good reputation, and also pay attention to the service coverage to ensure that timely technical support and maintenance services can be provided.
Post time: Feb-27-2026