Electromagnetic induction

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Electromagnetic induction

Electromagnetic pulse interaction with the system can be affected two systems caused long lines and structural effects, be divided. The effects of electromagnetic pulses of long lines, induced voltages on long lines power Vjary flow, cables or other conductors like pipelines is. Effects can occur at distances far away from the conductor to be guided inside the equipment. Structural effects, voltages and currents who can directly on the metal body of equipment, building structure, wiring, etc. induced cabinet containing equipment. The analysis of these effects are difficult to assess. Due to the complexity of structures, equipment, electrical properties, very different types of vectors between the facilities, part of the structure, various electromagnetic phenomena arise. To solve this problem requires hardware to software simulation, analysis and testing, which is quite special.

Frequency and amplitude

ZAMANIAN electromagnetic pulse shape and specifications for different types of threats and frequency of these resources is shown below.


In general, electrical and electronic equipment due to electromagnetic risk of experiencing are two types of damage: 1. transient damage. This type of damage usually occurs when the digital system bit error occurred while processing data or causing to be confused with the error message or the performance or cause the system Reset.2. The physical damage. This type of damage in a fire, explosion, burn graft semiconductor electronic circuits. Equipment that is most threatened and vulnerable are: 1. electronic equipment, computers, servers and data centers 2. control equipment, alarm Vhshdar 3. communication and equipment 4 types of processors Laptop 5. equipment power supplies, AC, DC 6. explosive and combustible.

Zones of influence

Infiltration and induction of electromagnetic waves and pulse equipment can through the body or wall openings or gaps and cable input / output. The influence of electromagnetic pulse device, shown in Figure 6 2. The influence of wave equipment are: - Wall- Door - Windows - Ventilation ducts - Antenna - Earth - Power and data cables - Tubes of various Kshyhay

Flow of electromagnetic induction in long lines

1. feeding long lines and Data Induced currents on long straight lines on the surface, to be Zyrthlyl. If the lines on the top floor complete with electrical conductivity, inductive current flow capacities, the electromagnetic pulse waveform will be like. Vkablhayy conductors that are more than a few feet from the earth, rise time longer. EC for land that is not complete, such as soil, an imperfect reflection of the Earth due to the stronger induction longer time than if the land is completely conductor, is. Short circuit current induced in a semi-infinite line on the soil for a field radiation pulse power, as shown in the figure below. The horizontal and vertical polarization induced by the radiation field is shown. Curve σ ═ ∞, a process that will complete the wire conductor is located on the ground induced. Flow proportional to the height of a line h, sink time constant τ, Ei radiation field strength and electrical conductivity σ Earth.Figure 2 9 with respect to the characteristic impedance of the line, peak right (E0), fall time constant (τ) radiation field, the speed of light C function, the direction (D) is normalized. Correction factor for the earth by guiding limit proportional to the intensity of the radiation field, can fall 3/2 of the time constant (τ) is the aim root of soil conductivity. An example is given below.

If on a transmission line length of 64 m above the ground with a conductivity of 640 Siemens per meter, pulse power with a range of 65 kV to 254 meters long proved to be twisted nanoseconds, a range of about 64 kA short circuit current on The line will be induced. Vplaryzasyvn waves bigger than waves with horizontal polarization vertical currents will be induced.In this case analysis, field strength of 65 kV per meter was used only while the right HEMP may be much larger than this amount. Based on our findings with regard to parameters such as spot Explosion, the observed effects induced polarization wave shape HEMP, peak between 5 and 64 kA short-circuit currents for the first part of HEMP obtained. Open circuit voltage induced in the bottom half of the limit line results ZO is the characteristic impedance of the short circuit current multiplication. 944 ohm impedance for the line in this example, the open circuit voltage will be about three million volts.

Induced currents on cables buried metallic coating

The land transferred. The field inside the Earth can be used on cables, pipes and other underground conductors, induce flow. Due to the weakening of the earth: but on electromagnetic induction conductor landfill Conductor lines is less than that of air. The conductors are in contact with the ground as bare conductors buried, at any point of view, basically with depth of field and coupling field transmitted on the conductor's point of view, is dependent. The farther from the point of view due to the weakening of the Earth, induced currents are very small. The normalized current waveform based on different amounts of cable burial depth of the earth, as shown in the figure below. With increasing depth, flow rate normalized on cable reduced its wave shape has been changed.An example of these changes is given below. Induced current is proportional to the time constant radiation field intensity is proportional to the electrical conductivity of the soil. Vertical to horizontal polarization radiation pulse amplitude E0 = 50 Kv / m and 254 ns fall time constant (τ) on the cable near the surface with buried electrical conductivity of 10-3 Siemens per meter (d = 0), the induced on it is about 2.8 kA.