Safety requirements during the works in electric units
Main safety requirements
Work in electric units, irrespective of tension, is carried out on written or oral the rasporyazheyoniya of the person, responsible for the electric unit. The written order is issued in the form of the dress. Written and oral orders are fixed in the special magazine. Permission to works on written or oral orders is given only by operation personnel.
In installations over 1 000 V, as a rule, work is carried out not less than 2 persons, one of whom has to have qualification group not lower than IV. At the voltage less than 1 000 V in some cases individual work of the person with qualification group not lower than III is allowed. Due to the possibility of defeat electric current, prior to work carries out technical and organizational measures of protection. Technical actions carry out in the following order:
- disconnect tension and take the measures excluding its oshibochyony giving to the place of work: include blocking, put the mechanical lock on the drive of the disconnector, the breaker, the separator, predokhrayonitel remove, establish temporary barriers;
- hang out precautionary posters on the switching apparayotura, on constant and temporary barriers;
- check whether there is tension on the part of installation which is disconnected for work if it is absent, then immediately impose figurative grounding on current carrying parts of installation;
- attach the clip of figurative grounding to the grounding device;
- on site works hang out the poster "Work Here".
These actions are carried out by the personnel on duty servicing the electric unit. Let's consider each of them.
Shutdown of tension
On site works switch-off the equipment which is subject to repair, and those current carrying parts which during the work it is possible to approach on dangerous distance or to touch accidentally. The disconnected site is separated from all directions from where tension, can be served in the visible gap created by the disconnectors, the breaker removed by crossing points or parts of the busbar and also vyklyuyochatel of loading and separators if they have no automatic drive on inclusion.
It is not allowed to work on the equipment separated only by the switch. In order to avoid the return transformation from the lowest tension power and measuring transformers disconnect both from high, and from medium and lowest voltage.
Drives of hand-operated disconnectors mechanically lock the padlock, the special bolt or the pin for prevention of their wrong or spontaneous inclusion. On drives with pnevmatiyochesky management lock the air intake valve. From tanks air is lowered. At distance control remove safety locks of both poles in the power chain of the drive.
In electric units up to 1000 V tension is disconnected by hand-operated switching devices.
Safety rules demand that the disconnected provision of contacts was visible with front or from the back party of the panel. For this purpose it is necessary to open guards, doors of casings.
Barrier of the place of works and posting of posters
If the places of works located close current carrying parts cannot be disconnected, reliably protect them.
In electric units up to 1000 V it is allowed not to disconnect current carrying parts available to touch if they are protected with pads from the isolating materials.
On temporary barriers of the site of repair work and on constant barriers of the next cells hang out the posters "Stand — the High Napryayozheniye!".
On open-air substations the site for repair work is allocated by means of the rope tense on site perimeter. On the rope fix the posters "Stand — High Tension!", turning them inside, to the place of work. If works are conducted at height, then on the design which climb to the place of work, hang out the poster "Get Here", on sosedyony — "Do not get — will kill!". On site works hang out the poster "Work Here".
Temporary barriers and posters are forbidden to be rearranged or removed. It is allowed to hang out and remove posters only to operation personnel which was carrying out preparation of the workplace.
To exclude accidental or wrong giving of tension on the switched-off equipment, on all keys of management and drives of switches, disconnectors, breakers and other switching appayoratura hang out the posters "Not Include — People Work". If otklyuyocheniye are performed for preparation works on transmission lines, then hang up the posters "Not Include — Work on the Line".
Check of lack of tension
After tension is disconnected, temporary barriers are established and posters are hung out, it is necessary to prepare figurative grounding, to attach them to the grounding conductor and then to check lack of tension on the site of the installation intended for works. It is necessary to apply the index of tension to check of lack of tension.
Just before check of lack of tension check operability of the index approach it to the current carrying parts located on proximity and which are obviously energized. In the absence of nearby current carrying parts which are obviously energized or impossibility to check operability of the index on site of works, the index of tension can be checked in any other place. In this case falls of the index, blows, etc. have to be excluded.
Imposing and removal of grounding
After check of lack of tension ground and connect phases of those current carrying parts, will work at kotoyory or from which tension can be given. Grounding impose from all directions from where tension can be given so that the site which is disconnected for work was between them. The most reliable protection working from accidental emergence of tension is provided to these. For example, on the three-circuit power transformer of grounding put from 3 of its parties.
Figurative grounding, as a rule, are established by 2 rabotniyoka, one of which has to have the IV qualification group. At ediyonolichny operational service of the electric unit inclusion of the stationary grounding knives and also nalozheyony figurative grounding in installations up to 1000 Century is allowed to one person on duty.Top