Electricity will see live working safety measures

, charged operations
Live working in which there is no power equipment or work carried out on a line. In electric equipment or line, for example, in a special way (such as using insulation lever, equipotential, operation methods, such as water washing) testing, maintenance, repair, and individual components of changing a job.
Charged operation according to the operation staff whether direct contact with the electric conductor can be divided into direct and indirect assignments; According to the operation personnel operations of potential height can be divided into such as potential job, intermediate potential job and ground potential job. The main way in use live working are:
(1) indirect job.
(2) the equipotential homework.
(3) along the insulator string into the strong electric field operations.
(4) homework.
(5) the insulation work.

Indirectly charged operation is also called the ground potential operation, is refers to the workers standing on the floor or standing on the ground objects (such as the Eiffel Tower, tower cross arm), maintain and repair equipment live part of safe distance, use insulated tools to the operation of electric conductor. Ground potential operations, a leakage current flows through the human body, through the human body leakage current path is: - people - tools - > charged conductor insulation. Due to the human body resistance is small, the resistance of the insulated tools is very big, leakage current flows through the human body mainly depends on the insulation resistance of the insulated tools therefore requires the insulation resistance of the bigger the better insulated tools.

Middle potential job refers to the human body standing on the platform or ladder insulation insulation, or standing within the insulation higher qualified machines, hand-held tool for charged body insulation work. Middle potential job also belongs to the indirect job scope. The leakage current path of this assignment is: earth - insulation (ladder) platform - - insulated tools - charged conductor. Middle potential operations, one is charged body and the insulation between the platform, the body charged body, respectively. As a result of the capacitance coupling effect, the human body has a certain potential, at this point, the body potential above ground potential and below charged body potential, so homework personnel should wear shielding clothing when working and comply with the relevant provisions.

Such as potential job is to make the job personnel charged body and various parts of the potential of potential is always the same homework. Equipotential homework is one of the direct operation to the charged operation, it includes equipotential homework, insulation work, points to homework, etc. Equipotential homework, homework personnel in full screen, with the aid of all kinds of insulating safe appliance into the strong electric field. In the condition of equipotential, intimate and ground insulation and completely with the charged body under the same electric field, the human body and there is no potential difference between a charged body. Because under shielding clothes to protect workers body, through the body of the current is zero, therefore, workers can directly contact charged body.

Second, the charged operation general provisions

1, live working personnel should be trained and qualified in the exam. Participate in live working personnel, must go through strict training, process and test qualified before they can attend live working.

2, working ticket issued and the work head must be approved. Live working working ticket issued and working controller should have live working experience, familiar with live working site and operating tools, for some unfamiliar live working site, can organize on-site survey, to judge and determine the operation method and the measures should be taken. People working ticket issued must be approved by the factory (bureau) leadership, working controller can be approved by the project leader.

3, charged homework must be designated persons. Guardian should by personnel with live working practice experience. The guardian may not be directly operation. The scope of guardianship shall not be more than one operating point. Complex or tall tower on homework should add guardian tower.

4, the application of charged homework when new projects and new tools, must be approved by experiment and leadership. For more complex and difficult between the new project and development of new tools must carry out scientific experiments, confirm the safety and reliability, create operation process scheme and safety measures, and the factory (bureau) competent leadership (chief engineer) approval to use.

5, charged homework should be in good weather. In case of thunder, rain, snow, fog and other weather, shall not be charged operations; When the wind is greater than 5, usually should not be charged operations.

Thunder, lightning and induction lightning will produce lightning overvoltage, the overvoltage may cause damage to equipment insulation and live working tools, serious danger to personal safety workers; Rain and fog weather, insulated tools for a long time will be affected with damp be affected with damp in Pi days, make the dielectric strength decreases significantly; The hot weather, workers on the poles, wires will get sunstroke while working time is too long; Cold wind and snow weather, wire sag decreases, and stress increases, the job would increase wire load, wire break even happen; When the wind is greater than 5, the workers will appear larger lateral force, poor job stability, make it difficult to homework, guardianship visibility is poor, easy to cause accident.

Under special circumstances, when must be charged under the bad weather, should organize relevant personnel full discussion, take reliable safety measures, necessary and the factory (bureau) competent leadership can be implemented only after the approval (chief engineer).

6, charged homework must be approved by the schedule agreed to. Charged operation work in live working, head of the work before you begin, should contact with scheduling, scheduling of consent rear can be carried out, after work should report to scheduling.

7, charged homework should be discontinued when reclosing. Live working with one of the following situations should be discontinued reclosing, strong and shall not be sending:
(1) the neutral point grounding (grounding) directly effective single-phase grounding operation may cause in the system.
(2) the neutral point is not effective grounding (neutral point grounding or via arc suppression coil grounding) of the system and may cause short circuit in the homework.
(3) working ticket issued by people or working controller need to stop using reclosing homework.
It is forbidden to about downtime or restore reclosing.

8, live working equipment in the process of sudden power failure may not be strong power. If all of a sudden power outage in live working process equipment, the operators still see equipment for electric equipment. At this time, to deal with inspection instruments and their own security measures, in case of unexpected overvoltage, working controller should be as soon as possible contact with scheduling, scheduling before contact, head of the work may not be strong power.
The above provisions shall apply to communication at an altitude of 1000 m and below 10 ~ 500 kv high voltage overhead lines, power plant and electrical equipment on the potential, such as the middle way potential of potential and live working and low voltage electric.

Third, between the general technical measures

1, maintain safe distance between the person and the charged body. Homework personnel and the distance between the charged body, should guarantee in the power system inside and outside the biggest overvoltage amplitude does not occur when the flashover discharge. So, when the electric potential operations, person and the safe distance between charged body (minimum distances between) should not be less than the provisions of the table 5-1.

35 kv and below the electric equipment, can t meet the minimum safety distance table 5-1, the insulation of the reliable isolation measures must be taken.

2, limit high voltage games is strong to the point of not damaging the personal. If the job personnel body surface electric field intensity short no more than 200 kv/m, is safe and reliable. If more than the value, should take the necessary safety technical measures, such as on the human body to be blocked.

3, establish between the technical solution. Charged homework should be prior written technical scheme, technical proposal should include the operating process and strict operation procedure, and adopt reliable safety technical measures.

Number 4, charged operation, good insulator shall be not less than the specified number. Live working replacement insulator or on insulator string operations, good insulator number shall not be less than the provisions of the table 5-2 pieces.

Such as the 110 kv overhead line, perch insulator generally 7 piece, one good insulator shall not be less than 5 pieces. Charged homework or replace insulator on insulator string, is bound to sub 1 ~ 3 piece of insulator, and thus cause the change of the insulator string on the distributed capacitance, the voltage distribution is also changed, sub parts is not at the same time, the voltage change is different also, especially on both ends of the insulator caused by voltage change is more wide. Because of the limitation of each insulator compression capacity in order to ensure the reliable insulator string can rest after sub maximum overvoltage and keep a safe distance from effectively, the voltage level good insulator piece number not less than the prescribed number line

5, when charged insulator replacement should prevent wires fall off. Replace straight line insulator string or mobile wire homework, when simple catenary device is used, should be taken to prevent the backup protection measures when the wire fall off.

Replace insulator string or mobile wire must disconnect the homework, at this point, mostly using messenger wire rod, wire rod, line balance type card device, TuoPing special clamping device, such as in the work process, when loosen the clamp or disconnecting insulator string hanging ring, wire with tower release of the wires through the device point guard, only if the mechanical parts of the device defects, wire and release device, can fly line of serious accidents, therefore, to prevent the wire off the fly line accident, backup maintain measures should be taken, such as using two sets of insulation wire rod or solid insulation rope, will wire fastening position in the tower, lest lead off when working.

6, using special short-term (or shielding clothing) near the cross arm disassembly and assembly for the first piece of insulator. In front of the insulator string is not out of wire, disassembly and assembly came near the tower cross arm the first disc insulator must adopt special short wires or shielding clothing, can operate directly.
In disassembly and assembly near the cross arm the first piece of insulator, to cause the on-off of capacitive current loop in detail. Due to the insulator string voltage distribution is nonlinear, usually the first piece of the equivalent capacitance on the insulator is opposite bigger. Homework personnel if directly operated by hand, although the body has the resistance, but there are still a large current instantaneous stimulus through the human body, movement disorders and dangerous. Contact by cross arm the first piece of insulator, and a steady current through the human body, the current size by the surface of the insulator string resistance, distributed capacitance and the insulator smudgy degree of decision, serious when can reach several ma, cause a harm to human body. So, before the conductor is not out, should use the special short connection reliably short after the first piece of insulator discharge, transfer or shielding clothing the temporary stabilization of capacitance current flows through the human body.

7, charged homework should be set when the fence. In the city or densely populated areas, when charged, fences, shall be set up between the work site is strictly prohibited non-work personnel inside.