Power Line Emission Research Articles

An Investigation of the Third Harmonic Power Line Emission in the Topside Ionosphere During the Recent Solar Minimum Period

AbstractPower line harmonic radiation (PLHR) events are radiated by electric power systems on the ground at harmonics of the base power system frequency (50 or 60 Hz, depending on the region). We analyze the global third harmonics PLHR at 150 and 180 Hz using electric field data collected by China Seismo‐Electromagnetic Satellite during the recent solar minimum between January 2019 and December 2022. The average frequency spectrum over industrialized areas shows that the third harmonic has a high occurrence rate in the U.S. region, as well as in western China and northern India, but is very low in the European region. In particular, in the China region and the U.S. region, more than 11,000 and 24,000 dayside and nightside third harmonic PLHR events have been detected from 2019 to 2022, respectively. Compared to the 150 Hz PLHR occurrence rate detected above the China region, the 180 Hz PLHR occurrence rate above the U.S. region is higher, which reveals a significant regional difference. In addition, both at nighttime and daytime, the PLHR electric field intensities at 180 Hz are higher than that at 60 Hz above the U.S. region, which is also different from the result above the China region.

Electromagnetic Response of the Mid‐Latitude Ionosphere to Power Transmission Lines

AbstractTo foresee a plausible electromagnetic contamination of the near‐Earth space by anthropogenic activity, a magnitude of electromagnetic response in the upper ionosphere to 50/60 Hz power line emission (PLE) is to be modeled. For that we have calculated the spatial structure of electromagnetic disturbance in the mid‐latitude atmosphere and ionosphere immersed into an inclined geomagnetic field . The electromagnetic field is excited by a large‐scale 50/150 Hz oscillating linear current suspended above the ground. The elaborated model is based on numerical solution of full‐wave equations in a realistic ionosphere whose parameters have been reconstructed with the use of the International Reference Ionosphere (IRI) model. The PLE wave beam in the ionosphere is not guided by , but still is shifted equatorward from the vertical. The response of the nightside upper ionosphere is slowly decreasing with diminishing of latitude. The amplitude of PLE electric component in the upper ionosphere generated by the unbalanced power line current with intensity of 10 Amperes can reach 1 V/m which is sufficient to be detected by a low‐Earth‐orbit satellite. For a better insight into PLE transmission through the ionosphere a basic information about ELF waves in the multi‐ion plasma is provided.

Электромагнитное загрязнение околоземного космического пространства излучением ЛЭП

We present an overview, based on satellite observations at low Earth orbits, on electromagnetic radiation from ground power transmission lines at an industrial frequency 50–60 Hz. Particular attention has been given to Chibis-M and DEMETER satellite observations. The electric 40-cm antenna of the micro-satellite often recorded 50–60 Hz radiation (known as Power Line Emission (PLE)) when it flew over industrialized areas of the planet. The PLE spectral amplitude varied from 1.2 to 18 (μV/m)/Hz0.5, which corresponds to the electric field amplitude E~1 μV/m. We report results of numerical calculations of the electromagnetic response of the atmosphere and ionosphere to a large-scale surface emitter at a frequency of 50 Hz. According to simulation results, PLE with an intensity of ~1 μV/m observed on satellites in the nightside ionosphere at midlatitudes can be excited by an unbalanced current 8–10 A in a power transmission line above the earth's crust with conductivity of 10–3 S/m. At middle and low latitudes with an inclined geomagnetic field, the maximum response in the upper ionosphere to the transmission line radiation should be seen shifted equatorward, although this shift is less than that upon guidance by the geomagnetic field. The maximum amplitude of the electromagnetic response of the ionosphere to the power transmission line emission decreases for an inclined geomagnetic field, but insignificantly. To date, the PLE intensity in near-Earth space has turned out to be higher than the intensity of natural radiation in this range (Schumann resonances and ion whistlers), and continues to grow with the technological development of mankind.

Electromagnetic pollution of near-Earth space by power line emission

We present an overview, based on satellite observations at low Earth orbits, on electromagnetic radiation from ground power transmission lines at an industrial frequency 50–60 Hz. Particular attention has been given to Chibis-M and DEMETER satellite observations. The electric 40-cm antenna of the micro-satellite often recorded 50–60 Hz radiation (known as Power Line Emission (PLE)) when it flew over industrialized areas of the planet. The PLE spectral amplitude varied from 1.2 to 18 (μV/m)/Hz0.5, which corresponds to the electric field amplitude E~1 μV/m. We report results of numerical calculations of the electromagnetic response of the atmosphere and ionosphere to a large-scale surface emitter at a frequency of 50 Hz. According to simulation results, PLE with an intensity of ~1 μV/m observed on satellites in the nightside ionosphere at midlatitudes can be excited by an unbalanced current 8–10 A in a power transmission line above the earth's crust with conductivity of 10–3 S/m. At middle and low latitudes with an inclined geomagnetic field, the maximum response in the upper ionosphere to the transmission line radiation should be seen shifted equatorward, although this shift is less than that upon guidance by the geomagnetic field. The maximum amplitude of the electromagnetic response of the ionosphere to the power transmission line emission decreases for an inclined geomagnetic field, but insignificantly. To date, the PLE intensity in near-Earth space has turned out to be higher than the intensity of natural radiation in this range (Schumann resonances and ion whistlers), and continues to grow with the technological development of mankind.

Modeling ELF Electromagnetic Field in the Upper Ionosphere From Power Transmission Lines

AbstractThe expected magnitude of extralow‐frequency (ELF) electromagnetic response in the upper ionosphere to ground large‐scale power transmission lines at low Earth orbit (LEO) is modeled. The full‐wave system of Maxwell's equations is numerically solved in a realistic ionosphere whose parameters have been reconstructed with the use of the International Reference Ionosphere (IRI) model. We have calculated the altitudinal structure in the atmosphere and ionosphere of electromagnetic field and Poynting flux excited by an oscillating 50/150 Hz linear current suspended above the ground. The leakage rate into the upper ionosphere was shown to increase during nighttime hours and above a high‐resistive crust. The amplitudes of electromagnetic power line emission (PLE) detected by LEO satellites correspond to the unbalanced power line current intensity of about 1–10 A, depending on the crust resistivity.

Special Electromagnetic Interference in the Ionosphere Directly Correlated With Power System

Power line emissions and harmonic radiations have been recognized as a kind of electromagnetic interference to the near-Earth space environment. This study demonstrates their direct dependence on the terrestrial power system used. By examining electric field data obtained by the satellite DEMETER, we observed several typical 50-, 60-, and 180-Hz emissions above Japan originating from a 50-Hz/60-Hz hybrid power system over two consecutive days. We analyzed all the emission events of 50 Hz and its harmonic frequencies detected as DEMETER flew over China. In 2009, the number of power line harmonic radiation (PLHR) events suddenly increased when multiple ultra-high-voltage transmission lines were built and put into operation. Based on the seasonal and diurnal distribution of the observed events, we conclude that PLHR is closely related to power consumption as we observe that it is mainly distributed above highly populated places and as such the radiation may originate from the low-voltage power distribution network. The magnitude and frequency of electrical currents flowing through transmission lines during both regular and faulty operation that can generate emissions reaching the ionosphere are analyzed for different voltage classes.

Influences of radiation from terrestrial power sources on the ionosphere above China based on satellite observation

The environmental effect on the ionosphere caused by man-made power line emission (PLE) and power line harmonic radiation (PLHR) has become an increasing concern. Based on the observed data of 6.5 operating years of DEMETER satellite, by scanning the electric field power density time-frequency spectrograms, 133 PLHR events with central frequencies from 500 Hz to 4.5 kHz are detected in the near-Earth space above China. The fundamental frequency related well to the frequency of corresponding ground power system. Among the 133 events, 129 events have PLE events at the base power system frequency (50 Hz in China). The duration time of every PLE event covers that of the corresponding PLHR event totally. As the same with PLHR, PLE is also propagating in whistler mode in the ionosphere. In two events that are detected in the conjugate region of Australian NWC VLF transmitter, radiations with line structure in the vicinity of 19.8 kHz are detected, suggesting a possible interaction between the NWC signal and radiation from China’s power system.

Systematic investigation of power line harmonic radiation in near‐Earth space above China based on observed satellite data

AbstractThe environmental impact of power line emission and power line harmonic radiation (PLHR) in near‐Earth space has become an increasing concern. In the years 2004–2010, based on the data of microsatellite DEMETER, 133 PLHR events are detected in near‐Earth space above China. PLHR has a close correlation with the development of China's electric power network. Its central frequency appears to depend on the latitude. The geographic distribution of the events occurs in clusters. Several events take place continuously above specific regions. PLHR shows no significant dependence on geomagnetic activity. There are more events in daytime than in nighttime and more in winter than in summer. The differences of naturally generated whistlers and power consumption between day and night and the strong thunderstorms in local summer may lead to such diurnal and seasonal differences of PLHR.

Electric field of the power terrestrial sources observed by microsatellite Chibis‐M in the Earth's ionosphere in frequency range 1–60 Hz

AbstractThe power line emission (PLE) 50/60 Hz and the Schumann resonance (SR) harmonics were detected by the use of a compact electrical field sensor of length 0.42 m during microsatellite Chibis‐M mission in years 2012–2014. The initial orbit of Chibis‐M has altitude 500 km and inclination 52°. We present the space distribution of PLE and its connections with the possible overhead power lines. PLE has been recorded both in the shade and sunlit parts of the orbits as opposed to SR which have been recorded only in the nightside of the Earth. The cases of an extra long distance of PLE propagation in the Earth's ionosphere and increased value of SR Q factor have been also observed. These results should stimulate the ionosphere model refinement for ultralow frequency and extremely low frequency electromagnetic wave propagation as well as a study on new possibility of the ionosphere diagnostics.

Effects of low frequency electric fields on synaptic integration in hippocampal CA1 pyramidal neurons: implications for power line emissions.

The possible cognitive effects of low frequency external electric fields (EFs), such as those generated by power lines, are poorly understood. Their functional consequences for mechanisms at the single neuron level are very difficult to study and identify experimentally, especially in vivo. The major open problem is that experimental investigations on humans have given inconsistent or contradictory results, making it difficult to estimate the possible effects of external low frequency electric fields on cognitive functions. Here we investigate this issue with realistic models of hippocampal CA1 pyramidal neurons. Our findings suggest how and why EFs, with environmentally observed frequencies and intensities far lower than what is required for direct neural activation, can perturb dendritic signal processing and somatic firing of neurons that are crucially involved in cognitive tasks such as learning and memory. These results show that individual neuronal morphology, ion channel dendritic distribution, and alignment with the electric field are major determinants of overall effects, and provide a physiologically plausible explanation of why experimental findings can appear to be small and difficult to reproduce, yet deserve serious consideration.

Electromagnetic monitoring of the Earth's interior in the frame of the MEM Project

The MEM Project (Magnetic and Electric fields Monitoring) was activated in the INGV Observatory of L’Aquila since 2004. The principal purpose of the project is to create in Central Italy a network of observatories to monitoring the electromagnetic signals in the frequency band [0.001 Hz - 100 kHz]. This band includes natural signals (magnetic pulsations of magnetospheric origin, Earth-ionosphere resonance mode signals, atmospheric noise, and so on) and artificial signals (power line emissions, VLF radio transmissions, and so on). The innovative characteristic of the project is the approach chosen to study the complex problem concerning the representation of the spatial and temporal distributions of the electromagnetic fields in the band of interest. Both the distributions can be represented by some parameters containing the locations and the characteristics of the sources of the electromagnetic signals. When all the stations will be in operation the wide-band interferometry will be applied. Combining the simultaneous observations of the electromagnetic field measured in the stations of the network, we will be able to obtain detailed information about the investigated electromagnetic sources. A new measurement system has been developed to fulfil these requirements focusing on the automation of the measurements. The system is designed for long term recording of the electromagnetic fields in a wide frequency band. In the frequency band [1Hz - 100 kHz] the three components of the magnetic field and the three components of atmospheric electric field are processed in real time using DSP (Digital Signal Processing) techniques. In the frequency band [0.001 - 25]Hz the two components of the telluric field and the three components of the magnetic field are recorded as sampled (100Hz). One of the main scientific objectives of the MEM project is the long term monitoring of the geodynamical processes, such as the earthquakes, by the calculation of the Poynting vector, and the analysis of the magnetic transfer functions and impedance tensor. In the next years this kind of analysis can be useful to underline the possible correlation between the geodynamical processes and the local magnetic field anomalies.