Smart Grid

Smart Grid

The intelligent power line network is the backbone of the power energy system.

The most advanced current sensors allow utilities to monitor their overhead distribution lines to optimize their capacity and protect the locations from the cause of faults of high-impedance and consumption peaks violations etc., thus improving reliability and efficiency of the MV/LV Distribution Grid, power generators, renewable energies and distributed energy resources.


Split core current transformers(CT) and flexible Rogowski Coil CTs for low voltage transformer monitoring.

The J&D new line current sensors provide bi-directional energy current measurement for transformers connected to distributed generation (wind/solar), ensuring smart LV distribution transformers are still operating within their design constraints.


Overloaded and underutilized LV transformers are detected instantly by the J&D’s new line CTs with the solutions on ease and speed of installation, accuracy of patented outdoor rated and UV stable current sensors as well as compactness and robustness of design.

How to choose the right current transformers for Smart Grid

1) First, rank the important factors.

There are several different models of current sensors in various window sizes, split-core, flexible Rogowski coil, amperage ranges, and accuracy grades.

To choose a current sensors, it is better to first determine the model you need based on the maximum load current you are measuring and the size of the conductor you are measuring, and then choose.

– Split Core: Compact & light-weight line hinge design

– Air core; Rogowski Coil:
When space is limited or the conductors’ shapes are odd, then Rogowski split core would be the solution.

–> Split core, and Rogowski coil current sensors are designed to be easily installed without disconnecting any wires.

With so meters many variables, it is sometimes difficult to choose exactly the right current sensors for a low voltage transformer monitoring project. Various meter models require checking and selecting the output and accuracy of the current sensors. Some ways meter choice impacts CT choice:


2) CT outputs – Which input is your meter designed for? Voltage? or Ampere?

– Common industry standards are 333mV, 100mA and 1A, or 5A.


3) Does the meter have the ability to work with flexible Rogowski coils either by themselves or with an amplifier/integrator?

– Common industry standards are integrator output :333mV, 100mA and 1A, or 5A.


4) Do you require a Revenue-grade and Power quality monitoring CTs?

 – The standard Revenue Grade Current Sensors meet IEEE C57.13 class 0.6 and 1.2 standard and IEC61869-2 class 0.5 and 1 standard. And maintaining compliance with IEC 61000-4-30 Standards is paramount, especially with power quality monitoring equipment. The wide frequency range CT represents an excellent choice for harmonics and power quality.


5) Do you have CT’s adopt IP(International protection) code and safety certification standard certification?

– The new line current transformer set is now also available for outdoor use. The Rogowski coil of the UV version is equipped with a UV-resistant housing, housing protection class(IP67) and UV-protected cables. This enables permanent installation outdoors.

Maintaining compliance with UL61010-1 Standards is paramount, especially with low voltage transformer monitoring. If you currently use CTs or anticipate using them in the future, keep UL61010-1 or UL 2808 in mind.

Recommended J&D Current sensors