Measurement Of Electromagnetic Environment Research Articles

Design of Nanosecond-Level Transient Electric Field Sensor and Its Application in HVDC Converter Station

In this paper, a nanosecond-level transient electric field (E-field) sensor based on a monopole electrically small rod antenna is proposed. The working principle and design process of the sensor are analyzed in detail while a finite element simulation is carried out to verify the response characteristics of the sensor both in time and frequency domain, whose upper cut-off frequency can reach 680 MHz. For the purpose of assessing the actual detection capability of the sensor in HVDC converter stations, the sensor designed in this paper was used to detect the transient radiation E-field in the valve hall during the artificial short-circuit test in the Zhoushan 1200 kV five-terminal flexible DC transmission project. The measurement results of the transient E-field indicates that the sensor is able to respond instantaneously to the radiated E-field generated by the operation of the key power electronic equipment in the valve hall. It demonstrates that the designed sensor can be effectively applied in the scenario of the measurement of transient electromagnetic environment and non-invasive situational awareness technology for high-voltage devices in HVDC systems.

Micro-Cantilever Electric Field Sensor Driven by Electrostatic Force

With the development of smart grids and the energy Internet, large-scale monitoring of voltage and electric field data is required in all aspects of power systems, which requires the arrangement of various advanced sensors. Measurement of the electric field can replace traditional voltage transformers to realize the non-contact measurement of voltage, which reduces the insulation cost and the difficulty of operation and maintenance. Electric field measurement can also be applied in various other areas, such as equipment fault diagnosis, lightning warning, and electromagnetic environment measurement. Traditional electric field measurement devices, such as field mills, are bulky and costly, so they cannot be arranged flexibly on a large scale. In this paper, we present an electrostatically actuated micro-electric field sensor (E-sensor) with a piezoresistive sensing structure. The presented E-sensor is fabricated into a four-cantilever structure using microfabrication technology. The cantilevers are displaced under the drive of the electrostatic force, and the generated strain is transformed into measurable signals through piezoresistive materials. The presented E-sensor has the advantages of small size, low cost, low power consumption, and easy mass production. Moreover, the E-sensor has a high signal-to-noise ratio, high resolution, and wide measuring range. The experimental results show that the E-sensor has a linear electric field measurement range from 1.1 to 1100 kV·m −1 with an alternating current (AC) resolution of up to 112 V·m −1 ·Hz −1/2 and a cut-off frequency of 496 Hz, making it suitable for most applications in smart grids and the energy Internet.

Measurement and Test of Electromagnetic Environment of Power Transmission and Transformation Project Based on Full Humidity Condition

Currently, the power transmission engineering electromagnetic environment monitoring instrument is widely used but cannot realize the power frequency electric field monitoring if the humidity is above 80%. By analyzing the influence factors of the humidity on the measuring instrument, this paper puts forward the power frequency electromagnetic field measurement method in the full humidity condition. The comparison test and data analysis are carried out under different humidity conditions. The distribution characteristic curve of the power frequency electric field is calculated by Maxwell software, and the accuracy of the measured data is verified from the theoretical calculation. The analysis proves that the power frequency electromagnetic field is independent of the environmental humidity, which strongly supports the electromagnetic environment measurement on rainy days of high humidity weather conditions.

Measurement of electromagnetic environment of hybrid DC circuit breaker during bipolar short circuit fault

Hybrid DC circuit breakers (DCBs) have recently been used to break short-circuit fault currents to ensure safety in flexible DC transmission projects. However, electromagnetic transients from DCB operation can interfere with the secondary equipment and cause malfunctions. In this paper, the bipolar short-circuit test, which is the first short-circuit test for DC transmission line in flexible DC project in the world, has been carried out in the 200 kV HVDC converter station equipped with two hybrid DCBs. The transient magnetic field near the secondary equipment in the DCB hall were measured, and its characteristics were discussed. Furthermore, the relationships among the space magnetic field, the short-circuit current and the action of the power electronic equipment in the DCB were also analyzed The main findings are as follows. During the bipolar short-circuit process, the maximum space magnetic field intensity near the secondary device is 109 A/m, and the maximum rising rate of the magnetic field waveform is about 350 A/m/ms. The magnetic field strength reached its peak value at the moment when the DCB was blocked, as well as the short-circuit current. It can be indicated that the DCB can cut off the short-circuit fault current accurately and reliably. The results can provide reference for the immunity evaluation and anti-interference protection of secondary equipment, and its optimal arrangement in the DCB hall.

Development of a Transient Magnetic Field Sensor Based on Digital Integration and Frequency Equalization.

Transient magnetic field sensors are used in various electromagnetic environment measurement scenarios. In this paper, a novel magnetic field sensor based on a digital integrator was developed. The antenna was a small B-DOT loop. It was designed optimally for the simulation. The magnetic field signal was digitally integrated with the improved Al-Alaoui algorithm, resulting in less integration error. To compensate for the bandwidth loss of the optical fiber system, we specially designed an FIR (finite impulse response) filter for frequency compensation. The circuit was described, and the transimpedance amplifier was specially designed to ensure the low noise characteristic of the receiver. The sensitivity of the sensor was calibrated at 68.2 A·m−1/mV, the dynamic range was 50 dB (1–300 kA/m), the linear correlation coefficient was 0.96, and the bandwidth was greater than 100 MHz. It was tested and verified under the action of an A-type lightning current. The sensor exhibited high-precision performance and flat amplitude-frequency characteristics. Therefore, it is suitable for lightning positioning, partial discharge testing, electromagnetic compatibility management, and other applications.

Novel Channel Management of Wireless Medical Telemeters Based on Simulation and Actual Measurement of Electromagnetic Environment in a Hospital

Novel Channel Management of Wireless Medical Telemeters Based on Simulation and Actual Measurement of Electromagnetic Environment in a Hospital

The Simple Approach of Electromagnetic Environment Measurement Methods in Hospital

The Simple Approach of Electromagnetic Environment Measurement Methods in Hospital

The Simple Approach of Electromagnetic Environment Measurement Methods in Hospital

The Simple Approach of Electromagnetic Environment Measurement Methods in Hospital

云南边境地区电磁环境测试实践及建议

云南边境地区电磁环境测试实践及建议

The Impact Analysis of the Electromagnetic Radiation from the Ultra-High-Voltage Transmission Devices on the Automobile Experimental Base

Through the measuring of the electric field, magnetic field intensity induced by ultra -high voltage power grid equipment, the paper aims to study the impact of these on the basic performance of the test vehicles, the physical health of the personnel and the communication reliability of intelligent network connection as well as to evaluate whether the electromagnetic environment of the experimental base reaches the automotive test standards. At the same time, it concluded the basic measurement and evaluation methods of electromagnetic environment in automobile test base.

Analyses on Measurement and Simulation of Electromagnetic Environment of 10 kV/0.4 kV Box Type Transformer by Using FEM Method

随着中国城市现代化建设的飞速发展，城市配电网的不断更新改造，箱式变电站已广泛应用于住宅小区、商业中心、机场、企业、医院或学校等场所，与人们的日常生活息息相关。为了明确箱式变电站周围电磁环境的分布特征，本文选取了某小区10 kV/0.4 kV箱式变电站进行有限元仿真分析，并与实测数据对比，研究箱式变电站产生的工频电磁场分布特征，为合理评估箱式变电站的电磁环境水平提供理论和实验依据。结果表明：电磁环境仿真分析与实际监测数据具有很高的一致性。在箱式变电站实际运行状态下，距离箱体20 cm处最大工频电场强度超过1.0 V/m，最大磁感应强度值为10 μT，主要集中在进出线、缝隙和窗体附近，且随着距离增大均急剧下降，因此箱式变电站工频电磁环境水平远远低于中国环境标准中推荐的居民区的场强限值，即电场强度4 kV/m，磁感应强度100 μT，该参数对周围环境、居民生活和身心健康不会造成不良影响。 With the rapid development of Chinese city modernization and the constant updating of city dis-tribution network, box type transformer has been widely used in residential, commercial center, airport, enterprises, hospitals or schools and other places, closed to people’s daily lives. In order to clear the electromagnetic radiation distribution characteristics of box type transformer, this paper selected the 10 kV/0.4 kV box type transformer in a certain area by using the FEM simula-tion and then compared it with the measurement data, in order to study the power frequency electromagnetic distribution characteristics and provide theoretical and experimental basis for assessing the electromagnetic environment level of box type transformer. The result of simulation analysis is in a good agreement with the actual monitoring data. In the actual operation condition of box type transformer, the electric field strength is more than 1.0 V/m and the maximum magnetic flux density is 10 μT at the distance of 20 cm away from box, which mainly concentrate in the import line, the gap and windows and decrease with the increase of the distance. Thus, it can be concluded that the electromagnetic environment level is far below the recommended China residential environmental standard limits, in which the electric field strength is 4 kV/m and the magnetic induction intensity is 100 μT. And it could not cause adverse effects on the surrounding environment, residents' life and physical and mental health.

High-power calibration and measurement method for bio-electromagnetic study

A novel method for high-power calibration/measurement is presented in this work. This method employs a coupler and a dipole antenna to achieve high-power measurement. The coupler serves as a low-power sensor, whereas the dipole antenna is responsible for the high-power measurement. This method successfully calibrated a 600 W 13.56 MHz radio frequency generator and is potentially useful for even higher power measurement, as well as for hazardous high-intensity electromagnetic environment measurement, avoiding the use of expensive high-power metres.

Methods of evaluating human exposure to electromagnetic fields radiated from operating base stations in Korea

This article presents measurement methods used to determine the human exposure to electromagnetic fields radiated from operating base stations. In Korea, when evaluating the human exposure to electromagnetic fields from operating base stations, the measurement procedure is different between the following cases: in situ measurement and electromagnetic environment measurement. When performing an in situ measurement, compliance with human exposure limits is determined by the spatially averaged field value obtained within the space occupied by humans at one arbitrary position, but when performing an electromagnetic environment measurement, it is determined by the maximum value at the highest field position selected from several places.

Measurement of the Electromagnetic Environment of HVDC Converter Stations

The results of an experimental study on the electromagnetic environment of HVDC (high-voltage direct-current) converter stations are presented. Transient EMI (electromagnetic interference) as well as steady-state RI (radio interference) and TVI (television interference) measurements were made at the Arnott station of BC Hydro and the Chateaguay station of Hydro-Quebec. The maximum values of the electric and magnetic fields measured inside the valve halls of Arnott station are 1.8 kV/m and 3.2 A/m; outside, they are 0.28 kV/m and 0.4 A/m respectively. These values cover the range of normal operation, including start-up and stopping of the converter station. During normal operation of the Chateauguay station, maximum electric and magnetic fields of 0.7 kV/m and 1.1 A/m are measured inside the valve hall; outside, they are below the sensitivity of the measuring system. It is recommended that immunity testing be carried out on electronic equipment to be used either inside or outside the valve halls of converter stations at transient electric and magnetic field levels of 5 kV/m and 10 A/m, respectively, with approximately 1 mu s risetime and 10 mu s duration. >