Types of electroprotective equipment and tools
Classification of protective equipment
The devices, devices, prisposobleyoniya and devices serving for protection of personnel against defeat as electric current, influences of the electromagnetic field, ozhoyog the electric arc call electroprotective equipment. They are subdivided into the main and additional.
The main call such protective equipment which isolation reliably maintains the operating voltage of electric units. With their help it is possible to concern the current carrying parts which are energized.
Serve as the main protective equipment:
- in installations of 1000 V and below - clamp-on ammeters and the isolating, dielectric gloves, the tool with izoliroyovanny handles, indexes of tension;
- in installations it is higher than 1000 V - the bars isolating (operayotivny and measuring), the pincers isolating and tokoizmeritelyyony, the indexes of tension isolating devices and prispoyosobleniye for repair work isolating ladders, platforms, drafts, the panel board gabaritnik isolating links of the telescopic tower.
The main protective equipment produce from materials with the usyotoychivy dielectric characteristic (bakelite, porcelain, ebonite, the micarta, special plastic, improved laminated playostik, etc.).
Additional call such protective equipment which in itself cannot provide at this tension the bezopasyonost from defeat with current. They can be used only together with fixed assets of protection and serve also for protection against tension of touch and step voltage, against burns as the arch and products of its burning.
Serve as additional protective equipment:
- in installations up to 1000 V - the dielectric galoshes, dielekyotrichesky rugs isolating supports;
- in installations it is higher than 1000 V - dielectric gloves and dielectric boats. In rooms with the increased danger, besides, the isolating supports and dielectric rugs.
The fixed and additional zayoshchitny assets which are in operation (except the isolating supports, dielektricheyosky rugs and bars for grounding imposing) periodically put on electric tests. Size test tension, admissible size of the leakage current through the ispytuyemy product, time and terms of tests, surveys are regulated "By instructions for use and tests of the protective equipment used in electric units".
The isolating bars - are used for works close or on current carrying parts of any tension. They consist of 3 main parts (fig. 1a): the worker 1 isolating 2 and handles - capture 3. Depending on assignment the working part of the bar has the different design. For example, in bars for tension izmereyoniya on certain isolation centers in the daisy the working part is executed in the form of the removable head, the bakelitovy tube 4 closed by caps 5 in which the replaceable probes 6 connected to the measuring device 7 fasten. At measurements it is possible to incline the head on the corner to 45 °C the help pivotally - the springing connection 8.
In operational bars the working part is executed in the form of the stalyyony tip 1 with the finger of 2 (fig. 1b) for capture vezhy the disconnector or in the form of the clamp.
There is the ring 3 with the thread for fastening of the index of the napryayozheniye.
The isolating part of bars of any assignment can consist of several links 2 connected by couplings 10 (fig. 1a). The number and length of links depend on operating voltage. The handle capture 3 is separated from the izoliruyuyoshchy part by the restrictive ring 11. On the handle put the stamp 9 with the indication of date of sleyoduyushchy testing, operating voltage, number of the bar and the name of the laboratory making testing.
The isolating pincers (fig. 2) - are used for work in electric units of napryazheyoniy 35 kV and less. помощью change inserts of predoyokhranitel from them, remove or nadeyovat the isolating caps on knives of single-pole razjediyonitel, etc. Pincers consist also of 3 parts: the working part — sponges 1, the isolating part 2 and the handle of capture 3.
Clamp-on ammeters, for example the Ts-91 type (fig. 3), are used for alternating-current measurement to 500 A in odinochyony conductors without rupture of the chain at the voltage up to 600 V. The working part of clamp-on ammeters consists of the connector magnetic conductor 1 on which in the body 2 the vtorichyony winding is placed. The ampermeter 4 which limits of measurement change the switch 3 is connected to this winding. Thus, clamp-on ammeters represent the current transformer which primary winding is the conductor 5, okhvatyyovayemy the connector magnitonrovod. I will corrode it is carried out by pressing the lever 6. The device can be used also for measurement of tension of 0-300 and 0-600 Century. For this purpose it is supplied with 2 conductors 7 with tips which are inserted into special slots on the device body.
In installations up to 10 kV apply pincers with the ampermeter installed on the working part to measurements. Them it is possible to make measurements when the possibility of electrical breakdown between phases or on the earth is excluded (because of reduction of insulating distances the working part of pincers at measurement). On cables over 1000 V measurements are allowed to be made only if cable cores are isolated, and distance between them more than 250 mm. Measurements are performed in dielectric gloves, holding pincers suspended and not bending down to the ampermeter.
Indexes of tension. To verification of presence or lack of tension on current carrying parts of electric units up to 110 kV apply indexes of tension. In indexes of voltage over 1000 V for detection of tension the luminescence of the neon lamp is used, at course via it the capacity current. The index is the field instrument consisting of 3 parts: the worker isolating 5 and handles captures 6 (fig. 4). The working part consists of the bakelitovy tube 1 in which the neon lamp 2 connected to the metalyolichesky probe 3 and the condenser 4 is built in. On the stamp 7 the operating voltage of the index and date of the following its testing are specified.
Before check of lack of tension check the index ispravyonost, bringing closer its probe to the current carrying part, заведомо being energized, and being convinced that the lamp at the same time shines. Then touch with the probe the all 3rd phases on switches and disconnectors on both sides of the otklyuchenyony part of installation and are convinced that the lamp does not shine. It is impossible to draw the conclusion about lack of tension at all on pokazayoniya of signal lamps and voltmetyor as they are only aids контроля.
When checking lack of the nayopryazheniye on lines up to 20 kV when measurements are conducted with wooden support or ladders, the capacity current is insufficient for the lamp luminescence. In this case grounding of the ukazayotel by the special conductor in the place of the connector of the isolating chayosta 8 is allowed. Check of operability of the index and lack of tension is carried out in dielectric gloves.
In electric units up to 500 V the ukayozatel called by tokoiskatel of the TI-2 type (fig. 5) (UNN-90, MIN-1) use, the courses working by the principle through the lamp of the glow discharge 3 wattful currents, the limited with a resistance of 2. The lamp, resistance and probes 1 which concern current carrying parts are built in in handles, vypolyonenny of the isolating material. Use of control lamps for detection of tension is forbidden.
The tool with the isolated handles as the main sredyostvo of protection is used only in installations up to 1000 V. Handles of the tool have to have smooth, without cracks and hangnails insulating covering from moisture resistant non-brittle insulating material not less than 10 cm long. It has to adjoin densely to metal parts, completely isolating the worker's hand from metal. After production or repair the instruyoment is tested of 2,5 kV within 1 min. In (fig. 6a) the set of the metalwork replacement tool which is used as the main protectant at the voltage up to 1000 V is shown.
The isolating supports apply in that case when it is difficult to execute the zazemyoleniye or nulling or safety requirements are raised. The isolating support (fig. 6b) represents the wooden flooring strengthened on basic insulators from porcelain. Height of insulators from the floor to the lower surface of the flooring not less than 5 cm for installations of all napryayozheniye.
Protective equipment from dielectric reasons. For isolation, the person from the earth and from current carrying parts is applied by products from dielectric rubber: gloves boats, galoshes and rugs (fig. 6v). Unlike normal rubber dielectric footwear has no lacquering. Rubber easily is exposed to mekhanicheyosky damages, especially under the influence of moisture, light, high temperature, oils, gasoline, acids. Protective equipment from the reyozina therefore have to be stored in the closed cabinets or boxes.
Temporary barriers - apply at repair works to protection of personnel from accidental approach to the tokoyovedushchy parts which are energized and located near the place of work. Temporary barriers are wooden boards (screens) isolating pads, caps, barriers, cages. Some types of such barriers are given in (fig. 7): the isolating pad for the breaker from textolite (fig. 7a), the rubber cap which is put on knives of disconnectors (fig. 7b), the suspended screen for barrier of insulators and wires (fig. 7v).
Figurative grounding apply in the absence of the statsionaryony grounding knives to protection against wrong giving of the napryayozheniye on the parts of electric units which are disconnected for work and from emergence on them the induced tension. Figurative zazemleyony the ShZP type consists (fig. 8) of wires 2 for connection short of current carrying parts of all 3 phases of the electric unit, the wire 6 for their connection with the grounding device, zazhiyom 1 or clamps 5 for connection of grounding to the oborudovayoniya and the grounding tire.
Grounding is imposed by means of the constant or sjemyony bar for imposing of grounding representing the isolating part 3 with the handle capture which is limited to the ring 4.
On transmission lines it is allowed to use odnoyofazny figurative grounding. Wires are carried out flexible of copper veins, them choose section on thermal stability at the short circuit, but not less than 25 mm2 in electric units over 1000 V and not less than 16 mm2 in installations of 1000 V and below.
Before grounding imposing its operability is checked survey. Imposing of grounding is made in the following posleyodovatelnost. Check the index
tension, by means of kotoyory the lack of tension on the grounded part of the electric unit will be checked. Attach the zazemlyayoyushchy wire to the grounding conductor. Check lack of tension. At once after check by the grounding bar the grounding clip is imposed on the current carrying part and fix it. Remove grounding upside-down. All operations carry out in dielectric gloves.
To apply accidental conductors to grounding and to connect grounding wires by twist it is not allowed.
On current carrying parts of the place of imposing of grounding allocate with 2 black strips, the interval between which is smoothed out to gloss. On the grounding tire for ground connection usually mount special screw "wing nut" terminals.
Instructions for use protective equipment
The isolating protective equipment have to be used in electric units with tension not above what they are expected and which is specified in the stamp. Protective equipment should be used in dry weather; to use them in the open air during the rain, snow, fog, hoarfrost is not allowed. For this purpose there are special protective equipment. Are not allowed to the use as unsuitable protective equipment which testing term, ukayozanny in the stamp, expired. Before use protective equipment clean from dust, examine, check absence for them external damages.
For storage of protective equipment in distribution ustroyyostvo the special place which is equipped with kryuchyoka for suspension of bars, figurative grounding, predupreyoditelny posters, cabinets or boxes for placement of gloves, the boat, rugs, goggles, gas masks and the ukazayotel of tension is allocated. When transporting protective equipment obeyoregat from moistening, pollution and mechanical damages, hold them separately from other tool.
Nayochalnik of workshops, services, substations, regions of the network circuit, and in general on the enterprise — the chief engineer bear responsibility for providing the electric unit with protective equipment, their accounting, the correct storage and frequency of surveys and tests, withdrawal and replacement of unsuitable means. The personnel servicing the electric unit are responsible for availability, prayovilny storage, use and suitability of protective equipment. Neprigodyony and faulty protective equipment immediately clean up from the electric unit, the leading adminiyostrativno-technicians are notified on it.Top