Abstract

"Square-law inertial smoothing in models of electromagnetic compatibility"

  The problems of EMC exist in all spheres of the activity of the person - everywhere, where there are used electric current, magnetic and electric fields. Here, we have analogy with problems of ecology which is not external, but deep enough - methodological as in environmental protection, there exists underestimation of the problems of EMC that leads to low controlled quantitative accumulation of hindrances of EMC, which inevitably creates the qualitatively new critical situation with levels and composition of the contamination. The costs to overcome such situation will greatly exceed those to prevent it.

  One of the basic requirements for electricity supply systems is maintenance of EMC. Overestimation of evaluations of EMC leads to groundless increasing of capital investments, and understatement thereof leads to such losses as deterioration of products quality, reduction of service life of electric equipment, additional charges of the electric power, and in some cases - to deterioration of human health and reduction of labour efficiency. That's why high requirements are claimed to authenticity of methods of evaluation of EMC both on the stage of planning and in exploitation of the electric and consumption systems.

  Standard determines EMC technical facilities such as ability of the technical facility to function with the given quality in the given electromagnetic ambience and not to create electromagnetic hindrances, which are inadmissible for other technical facilities. Concerning the aims of power consumption by the electric environment is regarded to be electric supply system, whereas technical means shall be deemed to be electric equipment that receives useful signal: voltage. The voltage is disfigured by conductional hindrances spreading on wire. Thus, under EMC in narrow sense it is necessary to understand ability of electrical equipment to function normally in the system of electricity supply and not to create in it conductional hindrances which are impermissible for other electrical equipment.

  The tasks of providing of EMC are decided on the stage of planning and operation. It requires development of methods of calculation and measuring of indexes of EMC - values which qualitatively characterize influence of hindrances on electrical equipment. Authenticity of evaluation of EMC is provided by adequate mathematical description (design) of both electro-receivers and electric supply systems. The levels of difficulty of the models are defined by conditions of specific problems, moreover there are limits of simplification, for which the sense gets lost.

  Absence of knowledge creates an illusion that instinctively transparent indices of EMC may be enough, without devoting time to theoretical constructions, which as though are unnecessary to an “ordinary engineer”. On the contrary, paradox is that necessary simplicity of calculations and measuring for practice may be achieved due to researches in complicated though specific tasks. EMC standards play a significant role when solving EMC problems and EMC indices. According to purposes thereof we conventionally shall divide them onto net and consumer ones. Net standards determine requirements to EMC at points of general connection of the energy system and consumer, that makes it possible to reveal a disturber of EMC and levy penalties on it . Net norms cannot reflect peculiarities of each type of the equipment, and that is why they are either conditional or relate to one “standard” object: incandescent lamp 60 V.

  Consumer standards determine norms at clamps of specific equipment. Standard requirements determine technical limits: if such norms are broken, without additional ground it is necessary to improve EMC. Nevertheless it may be rational in complying with standard norms according to economic criteria; that is why EMC indices shall allow evaluation of hindrances losses for existing electric equipment.

  In most cases hindrances change quickly from the pint of view of their duration, that needs application of dynamic models of EMC. The level of models complication depends upon the aims of their use. By analogy with the theory of the electric loadings electro-receivers, will divide them on mass and unique ones. The models of EMC of mass electro-receivers are selected as maximally simple, qualitatively of the same types, which differ only by numerical values of parameters. Models of unique electro-receivers can be difficult, however much principles of evaluation of EMC are identical.

  Entrance processes in models of EMC are conductional hindrances. The choice of their mathematical description (mathematical model) is defined by conditions of specific targets. If random factors insignificantly influence results of researches, use the determined models. In the majority of problems, it is impossible to neglect random factors; therefore it is necessary to use stochastic models. Moreover, the determined processes in some cases are expedient for considering as a special case of stochastic processes. Practical use of theory of chances is possible because casual phenomena inherit nonrandom regularities, which exist objectively. Matters in relation to reasons of their origin relate to philosophy. The theory of probability operates the determined values and functions which represent regularities. That is why in probabilistic models, as well as in models from other sections of mathematics, there is nothing unusual. Abolition consists only in interpretation of results: probabilistic descriptions make statistical sense, as appear at the frequent recreation of questioning. It is impossible to foresee investigation of any supervision. Statistical stability is the condition of correctness of theory of probability. If it is absent, the process is indefinite, not casual.

  Practical importance of the probabilistic methods is that they allow forecasting the feature of more complex unknown phenomena by known features of the simple casual phenomena. Efficiency theory of probability is stipulated by the fact that narrower range of broad range of possible value distinguishes from the wide range of practically reliable values, as for which there are calculated optimization means and stabilization parameters of the mode. That is the way to achieve economy of such means.

  In projecting initial data are the diagrams of loads for separate electric receivers or their characteristics. These data are gained experimentally or from technologic calculations. In the first case models of individual load is probabilistic, because in operating institutions casual deviations from the calculated regiment are inevitable. Exceptions are automated objects. In the second case determined models are often used, as they correspond to periodic repeatedly – long – term mode. Electric receivers operate independently, notwithstanding the fact that summoned diagram is casual. Its characteristics are calculated according to methods of the theory of probability. Such a scheme of calculations is applied when solving tasks of EMC. In operating electric systems it is possible to obtain casual diagram of mode parameters, which are used for assessment of conformity of EMC indices to standards and calculation of probabilistic losses from breach of EMC.

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