Ph.D., Sapa Vladimir, master student, Azizovа Leila

Kostanai State University A. Baitursynov, Kazakhstan

Control of the electromagnetic environment

at power stations

EMC problems are not new. They emerged in the development of radio and initially interpreted as a search for means to combat interference with radio reception. In the last decades of the XX century dramatically increased the saturation of the production sphere of human life and the instruments and technologies based on the achievements of electrical and radio engineering. Modern man cannot imagine life without radio , television , telephone and other media. It has become commonplace to use high-tech industrial equipment, telecommunications and information technology. Numerous electrical and electronic appliances (microwave ovens, refrigerators, heaters, vacuum cleaners, etc.) become the accessory of everyday life. There is increasing their range, more complex and more expensive technical performance, increasingly some hardware interferes with the other. Moreover, with the development of electronics sensitivity, and hence the susceptibility to various interference rises. At the same time continuously increasing the level and frequency range of external industrial noise. All this every year exacerbating the problem of electromagnetic compatibility.

Contamination of the environment by electromagnetic interference is dangerous, both for hardware and for biological objects. Therefore, ensuring EMC is directly related to the quality of products, environmental protection, safety of life and the preservation of human health and property.

At power stations before placing them on a modern digital equipment protection, automation is necessary to monitor the electromagnetic environment. Also, periodic monitoring of the electromagnetic environment in order to identify adverse changes due to aging of the grounding device, renovations and the like. Work on the technical content of the work assess the electromagnetic environment should include the following steps.

Estimate the operational status of the grounding device, including ground protection from lightning. In addition to the classical procedure of checking spreading resistance grounding device, there is a need to monitor the quality of the electrical connections between the elements of large grounding systems.

Tracing communications grounding systems with special selectors for the repair work. It should be borne in mind that such devices usually provide only a rough idea of the geometry of the metal bonds within the grounding device is not possible to assess their quality. Determination of traces of currents spreading the lightning discharge and short circuit. Spreading significant currents in metallic constructions of cable channels, screens, cables, grounding buses in rooms with the equipment and the equipment enclosure itself is dangerous. Created with the field and crosstalk can cause a malfunction of equipment even with all the regulatory requirements for resistance are satisfied .Long-term monitoring of noise in the information circuits and power supply circuits. Recorded continuously present interference in a wide range of frequencies. Also appearing are monitored regularly transients. Oscilloscope with connected computer translated into the "black box" that allows unattended detect interference, corresponding waveform capture and record them in the computer's memory.

Theoretically, the time of the monitoring is not limited. Measurement of noise in the information circuits and power supply circuits for switching operations carried out with the help of modern digital oscilloscopes with memory function of the pulse signal. Selecting a setting trigger is dependent on the type of operation and the circuit in which the measurements are made. Digital representation of the waveform is transmitted to the computer, which allows further processing to implement them using mathematical packages. Assessment of quality of power supply voltage from the main and backup power is the definition of harmonic distortion, if necessary, change the current value is tracked within days or more. Being recorded waveforms switching to backup power, which allows to determine the length of the pause when there is no current. Estimation of levels of electromagnetic fields. Fields are used for the measurement of specific integrated appliances, antennas. In some cases requires the use of analytical methods. It concerns the definition of the levels of magnetic fields in the locations of the equipment at short circuit in the high-voltage networks with grounded neutral .Of these works require certain qualifications of personnel and the use of relatively expensive equipment.

Therefore, it is advisable to conduct such operations by specialized organizations or departments within the range of design work on the reconstruction of the object. The work must be carried out in close contact with the designers, leading the overall reconstruction project .Control of the electromagnetic environment during the period between the operation of the facility renovations appropriate to attract these tasks operating personnel. Relevant is the mass production of inexpensive and extremely easy to use devices. The main objective is to detect sudden-onset or hidden problems. If necessary, for their complete diagnostics and solutions may be carried out a complete examination, the same way as is done in the reconstruction.

References:

1. EMC Basics: a textbook for high schools / edited by Doctor of Technical Sciences, Professor RN Karjakin; Alttaysky State Technical University named after II Polzunova. - Barnaul: JSC "Altai Printing Plant", 2007.

2. Habiger E. Electromagnetic compatibility. The basis of its support in technology: Translated from the German / IP Kuzhekin; Edited by BK Maximov. - M. Energoatomizdat, 1995. - 304.