Search of places of damages of cables and pipelines always were an intricate and responsible problem. As by a modern apparatus it is possible to decrease the losses of time at searching for of places of damages, speech will go to shorten expenses on errors, assumed during searching works in this article.
Damages are in power cables, cables of connection, losses in pipelines require the rapid removal of places of damages for the trouble-free providing of enterprises and population electric power, services of connection, water, gas and heat.
Determining the locations of damages - it is the difficult to associate the system of searching works with bringing in of different repair services and subdivisions. It is not difficult to count up, that error at determining the only one location of damage are a few thousands, and on occasion, ten of thousands of National currency losses. Thus, it is difficult to count up the losses of enterprises which remained without electric power or waterless.
Therefore, quality and continuity of providing of services of energy supply companies before a population and enterprises is the point of honor and own image. The technical providing and providing services power mediums are attended with the senescence of communications and equipment on their service. Expenses on repair are determined, above all the things, by possibility and state of searching apparatus.
In many enterprises an apparatus is exploited 60-80s years of issue. The element base of those years did not allow to create the highly sensitive receivers and acoustic sensors for the effective, exact and rapid search of damages. The produced apparatus of 90s as a rule was inexpensive, counted on a mass user and, as a result, primitive.
The search of damages such apparatus is in many cases impossible from a low sensitiveness and weak protection from the hindrance of receivers, weak power of generator, non-stability parameters at the change of temperature of surrounding air, and in many cases results in erroneous determination of places of damages. Many leaders on old times live by today, not reflecting, that an economic effect from introduction of new technique makes thousands of percents in a year, and it isn't difficult to count up, knowing that renewal of only one site of damage makes from three to ten thousand hryvnas. A device covers a cost itself on the first weeks of exploitation.
Abroad the basic producers of searching apparatus, Germany and England, very well know an economic effect from the sale of the apparatus, at least, on an order higher than cost our. Domestic devices, producible LTD. «Kvarc-elektronik», not at all yielding to in quality and possibilities the imported equipment, stand far less than foremost from low solvency of our communal enterprises, and we try to come into this a notice accountable for position of matters of chiefs.
In an order to get an economic effect from introduction of new technique, it is necessary to know, what requirements the modern searching complex of apparatus of damages of communications must answer. Modern searching complexes must confidently work in the conditions of hindrances, electricity transmissions created lines, by transformer substations, tram-car and trolleybus lines, stations of cathode defense. The filters of receiver must weaken the signals of hindrances which in ten of thousands of one time exceed the useful signal of generator.
The search of places of damages of cables and pipelines is based on a reception and signal of generator of the set tonal frequency processing, it is therefore important, that a receiver had the three appearance of indication — pointer, digital and voice. Some types of damages are determined only on electric aerial which were not used before in practice. To these damages belong damage of isolation of tendons of cables by resistance to 10 MOhm, which have a direct contact with earth. Also determine the damages of isolation of pipelines, place of contact of metallic shell of cable with earth and unauthorized cuttings in electric aerial on pipelines, tiny flow of water. Electric aerial on the functions is the analogue of pin method, where by two pins, deepened in soil, produce measuring of levels of signal of generator, spreadable on-the-spot earth. However a pin method it is impossible to apply on hard coverages, such as an asphalt, concrete, sett.
Searching engines, as a rule, flusters a sure signal above the investigated communication, his extent. It is possible to say from experience of exploitation, that depending on the type of damage of cables, his type for electric networks power of generator must be no less than 100 W. Yet better, if it will be 500 W. Stocked on power guarantees the best signal, if a generator will be included on the chart of conductor-conductor at the interphase shorting or precipices.
100 WATT of power of generator must be had to those services which exploit pipelines in the conditions of city. It is municipal and regional gas economies, severage system, heating plant.
Power of generator 30 W suffices for the cables of connection and services, exploiting main pipelines. For signalers, using a high-frequency muldex, it is important to have a generator with a sine wave signal on an output. Such generator is needed to those services which serve the controlled from distance systems of automation. At such form of signal a generator does not create hindrances the workings ductings.
Working frequency of generator can be different, but such gets out, to be not multiple 50 Hz and to its accordions. In our devices for different modifications it is chosen 477 Hz, 1024 Hz, 1071 Hz, 1177 Hz, 8192Hz, and 8475Hz. On occasion, when in the use of customer there are devices on an armament with certain working frequency, comfortably him to order those frequencies, that allows simultaneously to work as new and old devices with our more powerful generator.
On the example of seeker of damages «Universal-911 M-7» we suggest to consider the technical decision of searching complex, intended for finding out damages in power cables. A device showed oneself, as effective and reliable. Today he is successfully exploited in composition laboratories and out of them on many enterprises of Ukraine and CIS, such as Krymenergo, Kievoblenergo, Nikolaevoblenergo and other. Let's consider workings frequencies of generator and receiver in more detail 477, 1177 and 8475Hz. Frequency 477Hz have energy of signal which is well audible through screening obstacles. So, at the search of interphase damage of high-voltage cable, the site of damage appeared under asphalt on a traffic way. Signal of generator by frequency 1177Hz by power 500 W was torn off at the beginning of road, probably because cable on transitions technologically lays in a steel pipe which is a good screen. It was not heard on other side of road of signal, I.e. an area long 30 meters was not listened. Commuting a generator on frequency 477 Hertzs, it was succeeded expressly to listen a signal, lay - strengthening above the places of damage and his complete disappearance after the places of damage. A site of damage was under a traffic way and it is certain within 10 sm. It was thus succeeded to avoid superfluous excavations and scission of cable.
Thus, metallic pipes, being a good screen for frequencies, near by 1 kHz, do not render the same screening operating on more LFS. Frequency use 477 Hertzs for the search of those damages, where the pointed tension on other tendons or shell of cable can hamper a search and signal will stretch farther after the mestome of damage, in fact, as is generally known, the signal of generator spreads not only due to pure resistance in the site of damage, put on other end of cable. The tendons of cable and his shell have a capacity in relation to earth, therefore through capacity resistance the signal of generator can go on after the places of damage. What below frequency of generator, the less than there will be influence of this capacity. Frequency 477Hz it is good to use for the parallell located communications. Because signal from our communication re-directed on nearby, which, in same queue, radiate also, an operator can be by mistake hammered together from a route and go away on other. That it did not happen, apply more LF - 477 Hz.
Frequency 1177 Hz most widespread among many searching devices, where the near are used on frequency 1024 and 1071 Hz. It is used in ordinary cases and most usual for a human ear. Frequency 8475 Hz intended for such damages, as precipices. The ragged tendon does not have pure resistance, and only capacity. The signal of generator will be so much the better audible in a receiver, than higher his frequency. The work of quarzing generator is protected from overloads at including, in the moment of throw of current. Output transistors are protected from an overheat and death because of errors at a concordance or floating character of resistance of loading. Two pointer indicator allow to choose the optimum mode of concordance. On one of them control a current in loading from 80A on loading 0.1 Ohm, to 1.2A on loading 500 Ohm. Thus tension makes on an output 550-600In, that on occasion allows to produce burning of cable for translation of his resistance from high-resistance in low-resistance to the steady interphase or monophase shorting. Ten limits of concordance from 0.1 to 500 Ohm allow by hand to set maximal power of generator — 500 W.
A generator is not afraid of short circuits and pointed tension on the tendons of cable from the side of other, live-line. Duration of impulses can be continuous or impulsive are 0.3 secs. Receiver of seeker of damages «Universal-911 M-7» produces finding out underground communications on depths to 30 meters. High sensitiveness — from a 0.03 microvolt, allows confidently to accept the signal of generator. Exactness of determination of line of route and depth of bedding makes ±5-10 sm. An electric of principle chart of receiver is a steady-state on tension. It guarantees normal work at the digit of accumulator to the min selection level. The element base of receiver and generator is carefully taken away on TKS and TKE. It allows confidently working at an ambient temperature from - 30 to +50 °C. All electronic components pass screening. Pays are inundated protective varnish that allows providing normal work in the conditions of sharp overfall of temperatures, when take away a receiver from a warm apartment to the frost and vice versa. There is an indicator of generator of acoustics in a receiver. On the panel of receiver light-emitting diode, which displays about the digit of high-voltage condensers, is set. A receiver is structurally executed in a corps, carried on a small strap. The barbell of receiver has small weight, made from plastic elements. In foundation of barbell magnetic aerials and knot are located for twisting in of electric aerial.
By a device «Universal-911 M-7» determine the different types of damages on any cables, both low-voltage — 0.4 kv. and high-voltage — 6-10 kv, such as:
- monophases in low-voltage cables without a screen with polychlore vinyl a shell, here resistance can make from a short circuit to 10 Mom;
- monophases in high-voltage cables 6-10 kv;
- interphases and precipices.
For the inspection of sites of damage of isolation on pipelines developed and a device is successfully exploited «Universal-911 M-4». The feature of device consists in that a receiver is executed on a double-channel chart, that allows simultaneously to determine the line of route and produce control of the state of isolation. The double-channel chart of receiver allows to shorten time of work in 3 times. The same device is used for the search of places of the unauthorized cuttings in on pipelines. For the enterprises of connection, water channel, the devices of modification are developed «Universal-911 of M, ...M2, ...M5». Modifications «Universal-911-M, ...M5» except for basic functions on determination of route and depth of bedding can work as the selector of metal, for determination of wells and lids of hatches. All devices have a function of determination of cable in the bunch of cables. For generators by power 30 and 100 W possibility of connecting of bearing-out scope is foreseen for the noncontact method of radiation of signal.
For those, whoever has skills on work with searching devices, the specialists of enterprise conduct teaching with a practical show on a ground, where it is possible to see as on the real pipeline or cable determine the locations of damages. There is the detailed methodical manual in the complete set of device. For those, who has long-term skills, but would like to promote the level of the knowledge, an enterprise conducts seminars with a practical show.
CHIP NEWS Ukraine, #10 (60), December, 2006
CHIP NEWS УКРАИНА , #10 (60), декабрь, 2006г.pdf
