Survey and switchings in schemes of electric units

The faces of operation personnel servicing electric units individually have to have qualification group not lower than IV (in electric units tension above 1000v) and III — in installations up to 1000 Century.

Схемы электрооборудования

Schemes of electric equipment.

At survey of the electric unit over 1000 V by one person it is impossible to enter for barriers, cameras of distributing devices. Cameras are examined immediately or facing the barrier. If necessary survey of cameras of the closed distributing devices with the entrance for barrier is allowed to one person with qualification group not lower than IV provided that in passes the distance from the floor makes: to the lower flanges of insulators – not less than 2 m, and to not protected current carrying parts – not less than 2,75 m at the voltage up to 35 kV and 3,5 m – at the voltage of 110 kV.

If distances less specified, then the entrance for barriers is allowed only in the presence of the second person with qualification group not lower than III.

Схема заземления в сети

The grounding diagram in network.

At survey do not allow to perform any work. At survey of distributing devices it is necessary to close the door in RU.

At detection of ground fault it is impossible to approach the place of short circuit on distance less than 4-5 m in closed and less than 8-10 m in open distributing devices. Approach on more short distance is allowed to this place only for production of operations with the switching equipment at elimination of ground fault and also in need of first-aid treatment by the victim. In these cases it is necessary to use protective equipment and to be guided by rules of first-aid treatment.

At survey of distributing devices, boards, buslines, троллеев, assemblies up to 1000 V do not allow to remove precautionary posters and barriers, to get for them, to concern current carrying parts and to make their wiping or cleaning, to eliminate the found malfunctions.

For the operation personnel servicing production electric equipment (electric motors, generators, electric furnaces, bathtubs and so forth) and the electrotechnical part of different processing equipment up to 1000 V, it is allowed to open individually for survey of the door of boards of starting arrangements, control panels and so forth. At the same time it is necessary to be careful.

All switchings in schemes of electric units up to 1000 V and also all simple (that is in schemes of one accession) and difficult switchings in distributing devices of 6-10 kV who are completely equipped with blocking devices from the wrong operations with disconnectors makes personnel operational and on duty individually without forms of switchings, with record in the operational magazine.

In schemes of electric units tension above 1000v if distributing devices are not equipped with blocking devices or are equipped by them not completely, difficult switchings are made by personnel operational and on duty according to forms of switching; two persons participate in operation surely.

Схема распределения потенциалов у поверхности земли в зоне растекания одиночного заземлителя

The scheme of distribution of potentials at the Earth's surface in the zone of spreading of the single grounding conductor.

When performing switching according to forms the person who received the order about production of operation has to fill out the form of switching with transfer of operations as the priority of their production; the form is signed by the one who makes operations, and the one who controls them. The form undertakes on the place of production of switching.
Before production of switchings the form is read by phone to the higher official who made the order about switching then the person on duty writes down its surname in the column "the person controlling".

It is necessary to write down in the form of switchings switching operations with switches and disconnectors, operations with protection and automatic equipment and also operations on imposing and removal of grounding as exact sequence of their performance. Test operations are not required to be written down.

By production of switchings in power supply networks the number of the tasks given to one crew is not limited. On each task before departure of crew the separate form of switchings has to be written out. The person making switchings is obliged to get by phone from the person on duty on network permission to performance of the task just before the beginning of operation.

All switchings and operations on installation of grounding necessary for preparation of the workplace in IS or TP, it is allowed to make allowing to work (according to the dress) together with the operator.
The senior on change (or the person conducting service of electric units) has to keep written (in the operational magazine) account of figurative grounding and before inclusion under tension – the sites which were under repair. He has to not only be convinced on site whether grounding are removed, but also to check on records, number and numbers of the sets which remained in the distributing device whether it is forgotten where figurative grounding.

In electric units and on substations with continuous watch of personnel inclusion under tension of the equipment which was under repair or testing, can be made only after acceptance by its personnel on duty from the responsible head of work.

In electric units without continuous watch of personnel and in networks the order of acceptance of the equipment after repair or testing is established by local instructions taking into account features of the electric unit and implementation of Safety regulations.

In case shutdown of shop electric equipment was made on oral (or written) to the request of shop personnel for production of any works, the following turning on of this equipment can be made only upon the demand of the person which gave the request for shutdown or authorized by it and at present it replacing.

Before launch of temporarily switched-off electric equipment according to the request of shop personnel the operation personnel is obliged to examine it, to be convinced of readiness for reception of tension and to warn the personnel working at it about the forthcoming inclusion.

The order of execution of requests for shutdown of electric equipment of the enterprise or workshop has to be approved by the power engineering specialist of the enterprise and is agreed with the head.

Disconnectors allow to disconnect and include:

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