News | | Nov 06,2025
In power industry monitoring, current measurement is a crucial factor in ensuring system safety and efficiency . Traditional current transformers and flexible Rogowski coils each have their own advantages and disadvantages, and are applicable in different scenarios.
Different measurement ranges and applicability
Traditional current transformers ( taking split-core Current Transformer KCT as an example):
The HEYI KCT series current transformers perform excellently in most common scenarios, easily handling low to medium current ranges.
However, as the current increases, the required size of the current transformer will continuously increase, making installation and use in environments with limited space or irregular conductor shapes very troublesome.
Because of its superior flexibility in current measurement, the HEYI FRC series Rogowski coils offer greater flexibility.
Their flexible design allows them to easily maneuver around complex or irregular conductors in confined spaces, making them suitable for applications involving high current, high frequency measurements, and short-duration transient fluctuation detection.

Installation scenarios and adaptability
The HEYI KCT series current transformers feature a conventional rigid design, requiring complex spatial layout and additional equipment support during installation, especially in environments where modification is difficult once the equipment is already installed. Improper installation may affect their measurement accuracy and safety.
HEYI FRC series allows it to be used in locations with limited space or irregular conductor shapes, minimizing installation difficulty .
Its flexibility simplifies measurement work in complex environments without damaging the existing equipment structure.
Comparison of measurement accuracy and frequency response
traditional current transformers possess good low-frequency response capabilities , their performance is actually inferior to Rogowski coils when handling high-frequency or transient current fluctuations .
Due to the use of a magnetic core, the frequency response of traditional current transformers is limited to some extent , making it impossible to accurately capture high-frequency harmonics and current fluctuations.
The FRC series features a non-magnetic core design, offering a wider frequency response range (10Hz to 10MHz) and enabling precise measurement of high-frequency harmonics and transient fluctuations.
Therefore, it maintains higher accuracy in high-frequency applications , making it suitable for more complex power quality analysis and dynamic change detection.

Differences in overload tolerance
Traditional current transformers are easily damaged when handling high currents or overload conditions, especially when equipment malfunctions.
Their design is often not optimized for overload conditions, which can lead to short circuits or performance degradation.
the FRC series Rogowski coils is their strong ability to withstand high current overloads. Thanks to their non-magnetic core, the FRC series is more composed when faced with instantaneous high currents and can continue to operate normally under overload conditions. This gives them better reliability in some extreme environments .
Superior security
Improper use of traditional current transformers can lead to safety accidents , especially in open circuits where dangerously high voltages may be generated.
Without proper handling, the secondary windings of the current transformer may be damaged, potentially causing equipment failure or endangering personnel safety .
The FRC series offers superior safety advantages because it employs a non-invasive measurement method, avoiding direct contact with high-voltage current and thus preventing potential electrical safety hazards . Furthermore, it does not draw current from the main power supply, further reducing electrical safety risks during operation.

Typical application cases
Current transformers are a very suitable choice in conventional power distribution systems, low current monitoring, and relay protection systems. They can provide stable and reliable measurements in these environments.
For applications requiring high precision, high-frequency response, and installation in complex environments, the FRC series Rogowski coils perform exceptionally well .
For example, in scenarios such as electric vehicle charging stations, power substations , and power quality monitoring in industrial automation , the FRC series Rogowski coils provide more accurate current monitoring, and the installation process is also very simple .
Summarize
Traditional current transformers (CTs) are suitable for standard applications and have a stable structure, but their weakness lies in the fact that they may be limited in high current, transient fluctuations and complex installation environments.
The flexible Rogowski coils (FRC series) have a wider range of applications, are more adaptable, and can provide higher accuracy measurements, performing better in power systems, electric vehicle charging stations, and complex industrial environments .
Choosing a suitable current measurement solution can not only improve system safety but also increase work efficiency and cost-effectiveness. Considering specific needs, HEYI’s flexible Rogowski coils (FRC series) are a current solution worth considering.
Compay:HEYI Electrical Co., Ltd.
Brand: HEYI/ASCT
Contact: Bethy
E-mail: heyi@heyiele.com
Tel: 86-13968747975
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