Rogowski Coil Current Transformer Research Articles

Study on harmonic metering characteristics of Rogowski coil current transformer

This paper introduces the harmonic requirements of a power system transformer and the principle of the Rogowski coil electronic current transformer, summarizes the simple and practical methods for harmonic measurement of the Rogowski coil electronic current transformer, and conducts harmonic measurement of the electronic current transformer through high-precision harmonic source and standard current transformer and transformer calibrator. The results show that this method has strong applicability and simple operation, which greatly enriches the harmonic measurement methods.

PCB-Embedded Spiral Pattern Pick-Up Coil Current Sensor for WBG Devices

This paper proposes a current sensor for wide bandgap (WBG) devices. The current of a power semiconductor device is mainly measured using a Rogowski coil, an active current transformer, and a coaxial shunt resistor. The Rogowski coil and active current transformer are not suitable for the current measurement of surface mount WBG devices due to their operating principle. The coaxial shunt resistor causes parasitic inductance. Since WBG devices are more sensitive to parasitic inductance than silicon devices, parasitic inductance may affect circuit operation. To overcome these problems, this paper proposes a printed circuit board (PCB)-embedded spiral pattern pick-up coil current measurement for WBG devices. The proposed pick-up coil has high mutual inductance compared to the conventional pick-up coil, so the measurement sensitivity is high. In addition, there is no need for additional processing outside the PCB. Experimental results using a double pulse tester circuit are provided to verify the performance of the proposed current sensor.

Transforming characteristics of the Rogowski coil current transformer with a digital integrator for high‐frequency signals

The Rogowski coil current transformer is widely used in intelligent substations for its rapid response, wide bandwidth measurement, and non-magnetic saturation. In most cases, it works with a digital integrator to restore the differential signal output by the coil. However, its output waveform can be deformed when transforming high-frequency signals generated in the transient process of the power system. The working process of the Rogowski coil current transformer is presented, including Rogowski coil head transferring, analogue filter filtering, analogue-to-digital converter sampling, and digital integrator restoring. The reason for the waveform deformation when transforming high-frequency signals is investigated by theoretical derivation. In order to show the waveform deformation phenomenon, an experiment is devised and the results output by the Rogowski coil transformer and low power current transformer are compared and analysed. Several measures to improve the output waveform deformation are proposed, such as increasing the sampling rate of the converter, decreasing the cut-off frequency of the filter, or replacing the digital integrator with the analogue integrator. The researches provide important guidelines for the application of the Rogowski coil current transformer with the digital integrator in the case of frequency aliasing.

高精度Rogowski线圈电流互感器技术研究

高精度Rogowski线圈电流互感器技术研究

Research on Harmonic Characteristic of Electronic Current Transformer Based on the Rogowski Coil

The nonlinear load present in the power system will cause the distortion of AC sine wave and generate the harmonic, which havea severe impact on the accuracy of energy metering and reliability of relay protection. Tosatisfy the requirements of energy metering and relay protection for the new generation of intelligent substation, based on the working principle of Rogowski coil current transformer, mathematical model and transfer characteristics of Rogowski coil sensors were studied in this paper, and frequency response characteristics of Rogowski coil current transformer system were analysed. Finally, the frequency response characteristics of the Rogowski coil current transformer at 2 to 13 harmonics was simulated and experimented. Simulation and experiments show that Rogowski coil current transformer couldmeet 0.2 accuracy requirements of harmonic power measurement of power system, and measure the harmonic components of the grid reliably.

Fault Location Using Local Mean Decomposition on Traveling Waves with Three Current Measurements in an Overhead Conductor

A fault-location scheme based on local mean decomposition on traveling waves with three current measurements in an overhead conductor is presented herein. In the fault-location scheme, local mean decomposition is used to detect the arrival time of the initial traveling wave at each measurement. To obtain more accurate wave velocity, a third Rogowski coil current transformer is used to measure the fault current in the midway of a transmission line besides a couple of measurements used by the two-ended traveling-wave method at both its ends. The faulted line section can be identified by comparing the phase angles of the measured current data at its two ends; wave velocity can then be calculated by the ratio of the length of the non-faulted line section to the time that the fault wave travels through this line section. The proposed scheme can reduce the errors of previous methods on wave velocity determination. After wave velocity is determined, the fault distance can be calculated according to the two-ended traveling-wave method. The proposed fault-location scheme is tested by many simulations, and the results demonstrate it has higher accuracy than those using wavelet transform and Hilbert–Huang transform.

Design and Analysis of PCB Rogowski Coil Current Transformer

Electronic current transformers are more suitable for the development of power system compared with traditional electromagnetic current transformers. Rogowski coil current transformer is one of three electric current transformers. According to the measurement principle of Rogowski coils, the equivalent circuit of PCB Rogowski coils is analyzed. By using four PCB Rogowski coils combined, a PCB Rogowski coil current transformer is designed and tested. The results show that the designed PCB Rogowski coil transformer has good linearity and high sensitivity and measurement accuracy and it can meet the requirement of power system.

The Application of Rogowski Coil in Power System

The traditional current transformer measurement device cannot meet the requirements of the rapid development in the current power system because of the outdated structure while the Rogowski coil has significant advantages. This article introduces some applications of Rogowski coil in power system. Now the research and application of Rogowski coil current transformer has become one of the most important research directions. Rogowski coil today has been widely used in electric power system.

Analysis on the Transfer Characteristics of Rogowski-coil Current Transformer and Its Influence on Protective Relaying

This paper systematically analyzes the transfer characteristics of the Rogowski-coil Current Transformer and its effect on protective relaying through theoretical analysis, experiments and simulations. The frequency characteristics and transient characteristics of Rogowski transducer and Rogowski-coil Current Transformer are deeply analyzed based on the physical structure of the transformer. It is revealed that broad bandwidth of the transformer can improve the performance of protective relaying, and the bandwidth is determined mainly by the parameters of the Rogowski transducer and signal processing circuits. It is also discovered that the measurement errors of transient current mainly depend on the abilities for the current transformer to reproduce an accurate replica of the decaying dc components, which is mainly decided by the decay time constant of the aperiodic component of transient current and the parameters of the integral unit. Finally, some measures are proposed for the performance improvement of Rogowski-coil Current Transformer to meet the requirements of protective relaying system in terms of structural design and testing standards.

Design and research of fiber optically powered Rogowski coil current transformer

By the two-fiber way to power for the probe in high voltage side and convey the pulse signal, the Rogowski coil photoelectric current transformer is constructed, solving the problem of electrical insulation between high and low voltage sides. The photoelectric conversion efficiency of optical fiber power supply may reach 50%, which can meet the demand of electricity utilization steadily. The digital signal processing method of V/F conversion makes the signal transmission has a strong anti-interference ability, and the experimental results show that this method for maximum error is 2% in the input range of 0∼50A.