The Research On The Transient Magnetic Interference Measurement Technology Of Smart Substation

With the rapid development of intelligent substation, secondary equipment installation gradually moved to a place near the primary equipment. These secondary devices are susceptible to be interferences by transient electromagnetic in the vicinity of high-voltage equipment, resulting protection device malfunction or inaction and secondary equipment damage. Intelligent substation is basis for strong smart grid, so the study of transient measurement techniques has great significance for enhancing the anti-interference ability of secondary equipment and accelerating construction of intelligent substation. According to the characteristics of intelligent substation transient magnetic interference, this paper presents a practical magnetic field measurement techniques and analysis methods, and develops a handheld instrument for transient magnetic field measurements f, analysis and recording in substation intelligence.This paper proposed the use of induced electromotive force per unit area as a norm of magnetic field interference after analyzing the transient magnetic interference principle. The principle and advantages of TMR magnetic field measurement technology were introduced.The instrument uses 3D magnetoresistive sensor made of TMR sensor production as a probe for transient magnetic field measurement. It is based on FPGA + ARM architecture, up to 40 MHz sampling rate of the magnetic field data collection and high speed cache. This paper completed the design of signal conditioning channels, the main control circuit, power systems, GPS and other circuits, achieving high-speed signal acquisition in triaxial transient magnetic field. It also designs and completes ARM-based control system software, realizing real-time display for three-axis magnetic field, the control system designs a friendly interactive interface, achieve a large capacity data storage, complete the interference level calculation, include GPS time stamp, and support USB communications. The instrument is easy to used, easy to carry, very suitable for outdoor work. Instrument’s range is±30Gs, AC channel bandwidth is from 10 Hz to 1MHz, orthorganaty error is less than 1%.Amplitude-frequency characteristic and linearity of this instrument was tested. Measuring performance of the instrument was tested in the steady-state magnetic field frequency and pulse magnetic field. The experiment proved that the instrument is a good measuring instrument for the steady-state magnetic field in intelligent substation and that the instrument has a very good ability to capture and measurement capabilities for transient magnetic interference signal.Research interference design for research instrument, Anti-jamming capability of the instrument was tested. Finally, this paper analyzes the instrument error model, propose a calibration method for three-dimensional sensor, and calibrate the instrument using three-dimensional Helmholtz coil.