Strelnikova  Galina Anatolevna

ABSTRACT

          Urgency of the subject

The analysis of the statistics of breakage the equipment shows that significant share of the short circuits is connected with origin defect to insulation in system 6-10 kV. So well-timed discovery and removal these defect will allow to prevent the much of the damages. However for estimation degree of aging to insulation necessary execution on working equipping the unceasing automatic check, providing discovery defect on early stage of the development. Only in this case can be received expected effect and increasing to reliability of the work of equipment. Development of the special methods and facilities of the checking is required for realization of the unceasing checking.

For the further increasing of reliability of the operating the electric systems is required introducing the working monitoring, technical diagnostics and forecastings of the remaining resource of the energy equipment. The number of the damages in nodes of the electric systems with engine (NESE) appears in consequence of development local or portioned defect to insulating the cables and windings of the electric motors. To prevent origin of such damages is possible due to well-timed discovery defect and their removal possible. For estimation of the condition of the cables and forecastings to their capacity to work use the different methods. The main defect of these methods is the need of the unhooking the equipment. Finding defect to insulation without unhooking the equipment execute on change parameter operating duty equipment. For determination possible range change parameter mode and adjusting the facilities of diagnostics uses the data, got by experimental way and as a result of mathematical modeling operating duty NESE. However available mathematical model does not allow to execute the studies an operating duty when change the place of the local defect to insulation on length of the phase of the cable or windings of stator of electric motor. Besides, principles of building facilities of diagnostics from external defect require the further improvement, for what necessary revealing the regularities of the change parameter by execution of modeling different operating duty also.

The purposes and problems of the study

The problem given studies is the development of the ways of increasing to accuracy of the determination of the complex conductivities to insulating the joinings cable-system engine of the equations of the current condition. The offered account steady-state and dynamic asymmetry is executed by way of the introduction factor of asymmetry. These factors are defined real-time on current of the inverse sequence I₂.

Already designed methods of the determination of the conductivities to insulating the joinings of the load on moding parameter, but they give the exact results under symmetry phases only. In real condition practically always is present asymmetry so calculation by these methods give greater inaccuracy.

 Scientific novelty and practical value

The base masters work is the algorithm, using importances phase current of the joining with damage, voltages of the phases for the land, as well as current to inverse sequence for the known mode of the distributing system. It allows uniquely to reveal the defect to insulation so possible its using when making as separate expert system of the determination local defect to insulation, so and introduction in existing microprocessor device of protection, automations, checking and governing the joinings 6-10 kV.

 The planned result

System reliability of supply in much is defined by trouble-free operation line electric issue, which much form the distributing systems by voltage 6-35 kV. The known that big part of damages in system of supply (approximately before 80% from the total number of the damages) happens to on distributing systems exactly.

The most wide-spread type of the damage in this sets are a single-phase closing to the land, which end hasp insulation in its weakened places.  The similar damages occur because of diligence of the insulation so hitherto remains the actual problem of the ensuring the efficient unceasing checking the condition to insulation and on its base of the well-timed finding and removal defect to insulation.

The majority existing methods and facilities of the checking to insulation on taken place damage and do not allow to reveal the marked reduction the level to insulation and define the place of this reduction. Besides, for realization of each method is required or installing the extras, or introduction under some scheme of the measurement of the operative current, worsenning quality of supply of the consumers.

The ways of increasing to accuracy of the determination of the complex conductivities to insulating the joinings cable-engine by means of systems of the equations of the current condition are developed. The offered account steady-state and dynamic asymmetry is executed by way of the introduction factor asymmetry. They made primary analysis result, got when use the considered method and laboratory studies. Is it hereinafter planned produce the deeper analysis of the method, give the most reliable and final score of its work, including inaccuracy got result. The long-run objective masters work is a making the programme product ready for experimental, but hereinafter and ubiquitous introduction in systems of relay-type protection and automations.

 At present (the April 2007) masters work is found in stage of the development. The final variant will get ready in autumn 2007. With questions possible to address directly to my e-mail or to leader masters work.