By hvhipot 
In the power system, CT (current transformer) plays a crucial role as it is responsible for proportionally converting high currents into low currents that are easy to measure for use in metering and protection equipment. The CT parameter tester is the key equipment to ensure the accuracy and correctness of these CTs. HV Hipot Electric Co., Ltd. has been deeply involved in the field of power testing for many years. Today, let’s talk about the CT parameter tester and see how it ensures the safe operation of power.
What is a CT parameter tester?
Simply put, a CT parameter tester is an instrument specifically designed to detect various technical parameters of CT. Its main functions include:
Ratio test: Verify whether the actual ratio of CT is consistent with the nominal value, which is the most basic and important parameter of CT.
Polarity testing: Determining the current direction relationship between the primary and secondary sides of CT is crucial for applications such as differential protection.
Impedance testing: Measuring the DC resistance of the CT secondary winding can help determine the quality of the winding and whether there are any short circuits or other issues.
Excitation characteristic test: Draw the volt ampere characteristic curve of CT to determine whether CT meets the specified accuracy limit (ALF) or protection level (PS class) requirements, which is the key to evaluating CT performance.
The things about CT parameter testing
There are many factors that affect the accuracy of CT parameters, such as the manufacturing process of CT, the usage environment (such as temperature and humidity), the quality of secondary side wiring, and external electromagnetic interference.
It is crucial to choose appropriate testing instruments for CT parameter testing. At present, CT volt ampere characteristic testers and CT ratio testers are commonly used testing tools in the market. The CT parameter testing series products provided by HV Hipot Electric Co., Ltd. have a wide range of applications in the fields of power metering and relay protection. They provide strong support for power users with high precision and reliability.
How can we do better?
To conduct CT parameter testing more accurately, you can pay attention to the following points:
Standardized operation: Strictly follow the testing procedures to ensure correct wiring and accurate readings.
Regular calibration: Regularly calibrate the testing instrument itself to ensure the reliability of its metrological performance.
Understanding principle: A deep understanding of the working principle of CT and the physical meaning of various parameters can better analyze test results.
Data analysis: Combining historical data and on-site conditions, conduct comprehensive analysis of test results to promptly identify potential issues.
HV Hipot Electric Co., Ltd. has been committed to providing advanced power testing solutions to help power workers complete various testing tasks more efficiently and accurately.
frequently asked questions
Q1: What are the main scenarios in which CT parameter testers are used? A1: CT parameter testers are widely used in handover tests, preventive tests, and CT production, manufacturing, maintenance, and repair scenarios in power substations.
Q2: What are the consequences of failing the CT ratio test? A2: CT transformation ratio failure will directly affect the accuracy of energy measurement, leading to errors in electricity bill calculation, and may even emit incorrect signals during fault protection, affecting the safety of the power grid.
Q3: What is the difference between excitation characteristic testing and transformer ratio testing? A3: The transformation ratio test mainly focuses on the linearity of CT, while the excitation characteristic test evaluates the performance of CT at different excitation levels in more depth, especially to determine whether it will enter saturation state.
Q4: How to choose the accuracy level of CT parameter tester? A4: The selection of accuracy level should be based on specific application requirements. For example, high-precision measurement requires higher-level testing instruments, while the testing of protective CT focuses on its performance under short-circuit current.