The nonlinear load in power system will distort AC sine wave to generate harmonics

which severely affect the accuracy of energy metering and reliability of relay protection. To meet higher requirements of harmonic metering and relay protection for the new generation intelligent substation

this study analyzes the working principle and transfer characteristics of Rogowski coil. According to the mathematical model of Rogowski coil

two main factors affecting the frequency response characteristics of the coil

i.e.

the coil’s internal resistance and distributed capacitance

are studied. The structural parameter model of external integral circuit is employed to analyze the influence of integral time constant on the frequency response characteristics of the current transformer with Rogowski coil. In addition

through Multism12.0 simulation circuit model

the frequency response characteristics of the current transformer under from second-order to 13 th-order harmonics are simulated

and experiment is conducted for verification. Results show that the current transformer with Rogowski coil can meet the requirements of power system for 0.2 grade accuracy of harmonic power measurement

and it can reliably measure harmonic components of power grid.