Electric equipment repair, according to reform in electric power industry, is assigned to the specialised enterprises. And every year such enterprises appears more and more that inevitably strengthens a competition between them. In these conditions reputation of repair shop as the reliable and highly skilled partner, the further, the will become the more defining factor in struggle for the customer. And "damp" reputation not completely checked switch which has refused through short time after spent repair can.

        Thus, neither at maintaining, nor repair shops do not have alternative, except wide use of methods and means of tests, the control and diagnostics of a condition of the worn out electric equipment. And the repair shop, before others realised this simple fact and seriously engaged in their introduction in the practice, can occupy in the lead position in the market of services of repair of the equipment; to the maintaining enterprise it will allow to reduce expenditures of labour by maintenance of the worn out equipment in working order [3].

        Let out devices of the control and tests of high-voltage switches are intended for carrying out of following tests and checks of switches:

   — Tests at the lowered pressure with definition of size of the minimum pressure of operation;

   — Managements of high-speed and time characteristics;

   — Tests by repeated approbations in difficult cycles;

   — Resource tests by working out and manufacture of switches.

        For an estimation of a condition of the high-voltage switch various ways are used, but it is the most convenient to carry out diagnostics of the switch by means of specially intended devices, such, as PKV and ÒÌ. Application of these devices reduces time of carrying out of complex inspection at substantial increase of its quality, and also allows to refuse major repairs carrying out. Besides, by means of devices PKV and ÒÌ it is possible to reveal latent defects, which, as it is known, one of the most dangerous.

        By means of the given special devices it is possible to receive schedules which are used at diagnostics of high-voltage switches for the analysis of a condition of the switch. Such method has received the name of a method of early detection of defects in mechanisms of high-voltage switches. He allows to find out not only malfunctions at an early stage of their development, but even small deviations in work of knots of the switch, being based on the schedules of process received by means of the device. The method consists in registration of process of moving of one of mechanism elements (mobile contact, traverses, a shaft of a drive and another) at start-up of the switch and comparison of the received schedule to the schedule completely the serviceable switch or with the schedule which has been removed from the same switch at its last inspection.

        Though in practice of the control of high-voltage switches the graphic form of display of results, apparently, for a long time and well-known however these schedules are inconvenient for direct perception and demand preliminary manual processing.

        At automatic measurements of high-speed characteristics by means of gauges of moving with high resolution it is possible to receive absolutely other schedules: speed depending on time, speed depending on a course, a course depending on time. They display processes of movement traverses and mobile contacts, their interaction with directing mechanisms, mobile contacts and buffers. Hence, on their appearance and its deviation from standard it is possible to make operatively diagnostics of malfunction of these knots right after a conclusion of the switch from operation [4]. Use of devices PKV, ÒÌ, allows Nikta:

   — in one and a half time to lower expenses of the enterprise for service of high-voltage switches;

   — twice to reduce time of diagnostics of the switch;

   — in some cases use of devices led to full refusal of carrying out of planned repair in view of a normal state of switches.

        Knowing, as conducted by the serviceable switch at inclusion and switching-off (behaviour of the schedule in the course of inclusion/switching-off), it is possible to reveal easily malfunctions of the switch under schedules.

        If the drawing of the serviceable switch is not present, but there is a schedule which has been removed on the surveyed switch at its previous inspection, that, comparing these two schedules, it is possible to track tendencies of changes and to assume, that to expect from the given switch in the future.

        Such difficult defect as backlash in mobile parts, by devices PKV, Nikta and ÒÌ also is defined. Backlash create faltering loading from mechanisms of three poles on the general drive through which there is a mutual influence of three processes of the movement, well observed at combination of schedules "speed-time" of two (or three) poles.

        Under the schedule "speed-time" is diagnosed also one more defect — increased time of switching-off of the switch.

        Thus, it is possible to draw a conclusion that the method of diagnostics of latent defects by means of the analysis of the schedules received by devices PKV and ÒÌ, is simple, reliable and evident, allows to save time essentially. Schedules allow to define malfunctions and deviations at an early stage and more effectively to plan repair. Even the minimum experience in decoding of schedules allows to reveal knots and the devices of the switch demanding intervention of the repair personnel prior to the beginning of repair, not to subject unnecessary (and frequently and harmful) dismantling serviceable knots, thereby reducing repair time [5].

        There is also other method of diagnostics, it consists in the analysis of the scheme of the switching centre at operation current protection of zero sequence (CPZS) at switchings that allows to reveal the chains containing defective switching devices. This method has received the name of a method of diagnostics of malfunctions by means of relay protection and control.

        At switchings in switching centres (ÐÓ) 110–220 êV substations and power stations at a certain stage parallel chains in scheme switchgear can be created, for example, at replacement of the oil switch of any joining on roundabout the switch during the moment when both switches are included. At shunting of a chain of one switch process which it is conditionally possible to name «effect of replacement of a current» from one parallel branch of the electric scheme in another occurs another and presence in one of them of defects of contact system leading to increase of transitive resistance between contacts of the switch. In three-phase chains such process is easily found out on operation of the relay protection reacting to currents of zero sequence, – sensitive steps not directed or directed CPZS with the blocking relay of a direction of capacity. CPZS with resolving does not work, since In this case pressure of zero sequence 3U0 = 0.

        Otherwise process between contacts of not shunted switch develops. Process spark or arch burning between contacts of the switch in the presence of defect of contact system (oxidation, pollution, easing of pressing in of contacts, etc.) is unstable, and at some instant time when intensity of spark (arc) processes decreases, for example, at reduction of a current of loading, starts to increase Rïåð. Increase of transitive resistance leads to potential difference increase between switch contacts, to their overlapping by an arch and conductivity restoration [6].

        The effect of replacement of a current in one of phases of parallel 3-phase chains within one switchgear 110–220 êV creates conditions for operation CPZS in both chains since thus in one of 3-phase chains it is formed incomplete a mode, in another asymmetry of currents. Methods of indirect diagnostics on the basis of behaviour of relay protection it is possible to reveal a defective chain, and further methods of direct (technical) diagnostics to find the defective switch long before planned audit. It will allow to prevent heavy emergencies which can be connected with explosions of switches and fires [7].

        One more very widespread method of diagnostics, the method of infra-red diagnostics is. Infra-red diagnostics is the most perspective and effective direction of development in diagnostics of an electric equipment which possesses a number of advantages and advantages in comparison with traditional test methods, namely:

   — safety of the personnel at carrying out of measurements;

   — equipment switching-off is not required;

   — it is not required workplace preparations;

   — great volume of carried out works for a time unit;

   — possibility definition of defects at an early stage of development;

   — diagnostics of all types electric equipments;

   — small expenditures of labour on manufacture of measurements;

   — reliability and accuracy of received data.

        For thermal supervision and measurements use two cores "transparency windows" atmospheres 3-5 microns and 8-12 microns in which work thermovision. Now the given devices start to be used widely in many industries, a science and medicine.

        Application thermal diagnostics is based that presence of some kinds of defects high-volttge the equipment causes change of temperature of defective units and, as consequence, intensity change Infra-red (IR) radiation which can be registered thermovision devices [8].

        Measurements are necessary for spending in the absence of a direct sunlight, thus continuous overcast does not pass ÈÊ radiation of the Sun and carrying out thermal diagnostics is in certain cases possible in the afternoon at continuous overcast. It is important, that measured own radiation of surveyed object which is connected with presence and degree of development of defect [9].

        At diagnostics carrying out it is necessary to consider radiation factor surface surveyed object, and also a corner between an axis thermal the receiver and a normal to a radiating surface of object. At carrying out of measurements of the same objects it is necessary to have thermal the receiver on identical distance and under an identical corner to an optical axis to an object surface.

        At detection more heated zones it is necessary to estimate, first of all, whether is it a difference consequence in radiation factors, whether it is connected with presence of apertures or the planes located at an angle [10].

THE BASIC RESULTS

   1) The analysis of damageability of the switching equipment;

   2) The analysis of existing methods of technical diagnostics of the switching equipment of electric networks;

   3) Mathematical modelling of planning of repairs of switching equipment of electric networks and revealing possible ways of increase in the between-repairs period;

   4) Working out of algorithm of transition from system to service system «on a condition» switching equipment of electric networks.

THE CONCLUSION

        The analysis made in work has shown that modern development of methods of technical diagnostics of switching equipment allows to reveal authentically defects of designs of elements of equipment at an early stage of their development. It in turn allows to refuse system of scheduled preventive maintenance and to pass to system of service of switching equipment «on a condition». Also in the given work modern methods of technical diagnostics of switching equipment have been considered, and also the estimation of possibility of use of these methods is spent at transition to service system «on a condition». Three basic methods of diagnostics of switching equipment have been shortly described and characterised, namely: a method of early revealing of defects, a method of diagnostics of malfunctions by means of relay protection and control and a method of infra-red diagnostics

THE LITERATURE

   1. News electrical engineers: [Elektronny a resource] / and. G.Ovsyannikov//the Directory edition — 2008. — ¹ 2. — With. 50. — the Mode to access to mag. http://www.news.elteh.ru/arh/2008/50/20.php;

   2. Power and the industry: [Elektronny a resource]//the Newspaper — 2008. — ¹ 8. — With. 100. — the Mode to access to newspaper.: http://www.ird.vstu.edu.ru/obsh_pologen.html;

   3. News electrical engineers: [Elektronny a resource] / century D.Lastovkin//the Directory edition — 2008. — ¹ 1. — With. 49. — the Mode to access to mag.: http://www.news.elteh.ru/arh/2008/49/06.php;

   4. RD 34.45-51.300-97. Volume and norms of tests of an electric equipment. the 6th Publishing. - TH.:ENAS.1998;

   5. Nazarichev A.N.perfection of system of repairs of the electro-equipment of power stations and substations taking into account a technical condition: Äis. Dr.Sci.Tech.: 05.14.02 Ivanovo, 2005 390 with. RGB ODES, 71:06-5/256;

   6. Strategy MSaE and equipment diagnostics [Elektronny resource]//the Directory edition «News electrical engineers» – 2008 – ?2 (50). – an access Mode to mag.: http://www.news.elteh.ru/arh/2008/50/20.php;

   7. Russian Open Society "United Power Systems" TS-04-97 circular () from 12/29/1997 «About the prevention of breakages of oporno-rod insulators 110-220 ê»;

   8. Aronshtan J.L.Dyomin A.N.technique of the akustiko-issue control of porcelain insulators disconnector 110-220 sq. Works of the international scientific and technical conference "Izoljatsija-99", S-pt, on June, 15-18th, 1999 ;

   9. Sheykin A.A.quality assurance of products from high-voltage electroporcelain on manufacture. The collection of materials of 2nd seminar “Diagnostics of a technical condition of porcelain insulators of high-voltage switching devices”, Ì, VNIIE, on October, 27-29th, 1999;

   10. Omelchenko J.A.Shejkin A.A.quality assurance of products from high-voltage electroporcelain on installation and in operation. The collection of materials of 2nd seminar “Diagnostics of a technical condition of porcelain insulators of high-voltage switching devices”, Ì, VNIIE, on October, 27-29th, 1999.

REMARK

        The master’s work was not completed yet while writing this abstract of thesis. The date of completing is 1 December, 2010. The full text of the work and the material on this subject can be received from the author or its curator after the given date.