Ph.D. Sapa Vladimir, student Ramash Karim

Kostanai State University A.Baitursynov, Kazakhstan

Electric and magnetic effects on the biosphere and the technosphere

High voltage electrical networks have varied adverse effects on the biosphere and techno. Voltages and currents in the wires of power lines create in the surrounding fields, and in the land - stray currents. The result may be disturbing and even dangerous effects on the biosphere (people and animals) and technosphere (link signaling, pipes and other engineering structures). Stray currents in the ground causes increased corrosion of cables, pipelines, and other underground ear thing extended devices. Construction of power plants, transmission lines and substations requires exclusion of certain parcels of land, creates other negative environmental impacts. Dangerous influence - it is the impact that may pose a danger to life and limb of the system and the public, cause damage to the equipment and appliances or the false alarm and interlock circuits, creating the likelihood of, for example, a railway accident. With all of this to be reckoned with emergency or abnormal operating high voltage networks. When asymmetrical short circuits in networks with neutral solidly earthed (Un ≥ 110 kV) high currents occur in the ground and strong magnetic fields. They can cause dangerous magnetic influence. They create an electromotive force and the mutual voltage with respect to ground to air and cable lines , pipelines , transportation facilities, etc. In the 35 kV network with isolated neutral ground fault on one phase of the remaining two phases of the airline to line voltage rises. High tension electric field near overhead can cause dangerous effects on air communication lines in the immediate vicinity of the overhead line. Under wires EHV lines and ultra-high voltage at the surface, there is an increased intensity of the electric field E, even in normal mode. At E > 20 kV/m human touch to aggregate large vehicles with rubber tires can be dangerous. Through a person standing on the ground, will flow a significant portion of the capacitive current from wires overhead line to this machine. Hazardous galvanic influence causes more accidental short circuit current through the grounding device substations and transmission lines and ultra- ultrahigh voltage. These currents reach tens of kA, and the potential ear thing - thousands of volts. Additionally, it may be dangerous high voltage substation with the action taken on the rails, pipes, cables and other shells extended metal objects. Galvanic voltage component can increase the voltage difference between the line conductor and the grounded connection of the support line disposed near the support of emergency air line. Under the influence of interfering noise should be understood that arise in the area of high voltage in long-term (normal) mode of operation. They do not create immediate danger to the structures of the technosphere, but degrade the quality, reduce reliability or create difficulties for the normal functioning of communication, television, radio, etc. Interferences are not dangerous for the biosphere, but cause discomfort, impair health, impede normal life cycle or labor regime people. Operating currents in wires 50 Hz air lines form a magnetic field creating interferences in chains unmanaged remote power amplifier channels in the high points of the communication cables and other communication devices using the earth as a return conductor. Higher harmonic currents and voltages are highly undesirable: they adversely affect the operation of electrical networks, create additional losses in wires and magnetic circuits, local overheating, the resonant voltage rise in tonal noise (sound) channels of communication lines. The main work carried out due to the high-frequency channels. However, the communication channels at audio frequencies are basic in the extreme conditions, particularly at high ice on wires lines, when the attenuation of high-frequency signals in the channels is greatly increased. Higher harmonics in high voltage networks arise mainly due to conversion of semiconductor devices and electric melting furnaces, electric welding machines and due to saturation of transformer steel. Interferences currents of high frequency high voltage power lines on a link are caused by high-frequency channels, and the crown on the overhead line. Corona current pulses on the wires and insulators, superimposed on each other with an offset along the line and in time create energy loss and the overall level of interference and radio frequency interference in the air lines and communication lines. The frequency spectrum of the radiation, which creates interference covers the range from 10 kHz to 1 GHz. Interference at frequencies above 30 MHz have interferences on television reception and only occur when corona discharge lines 750 kV. Sources of interference in this case, in addition to the crown on the wires are partial discharges in the gaps and cracks insulators and pointed crown on the fitting. In good weather, the crown on the wires hardly disturbs television reception. The intensity of interference is characterized by the vertical component of the electric field near the surface of the earth E₃ [1, 2]. The level of interference is determined by the

Y = 20lg E₃ (1)

where E₃ - electric field, uV/m.

As the design frequency f = 0,5 accepted MHz. The permissible level of interference in good weather is 40 dB, which is in accordance with (1) gives E₃ = 100 uV/m. This electric field strength accepted as valid for a distance of 100 m from the extreme projection wire power line 300 kV and above. Increasing the radius of the wires at a constant field strength leads to an increase in the level of interference, as the recession field near the wire in the radial direction at the same time slows down, and create conditions for the development of more intense streamer corona. Radio interference are virtually independent of the number of components in phase, as there is a mutual electromagnetic shielding phase conductors. The magnitude of interference influenced by a number of factors, the main of which are: the radius of the wire, the weather conditions, the condition of the wire surface, the degree of pollution of the atmosphere. Rain, sleet raises the level of interference by 10 dB, dry snow, and drizzle on - 5 dB. When adding new lines interference about 4 ... 5 times higher than that of the wiring lines by aged. Full aging wires basically end after 4 ... 5 years of operation [1, 2].

Literature:

1. Electromagnetic compatibility in power engineering: Textbook / G Vagin, A Rags , A Sevost'yanov. - Moscow: Publishing Center "Academy", 2010. - 224.

2. Usachyov A Electromagnetic compatibility: Textbook / A Usachyov. - Ulyanovsk: 2001. - 44.