When working with electrical devices, safety is very important. One of the key points is the use of electrical protective equipment, which are objects that protect a person from exposure electric current. At the same time, it is important to know what insulating electrical protective equipment is used in electrical installations and what exactly they are intended for, as well as monitor their condition, including checking and replacing them in time.
What are the means of electrical protection and what are the terms for testing electrical protective equipment, will be discussed in this article.
The safety of work carried out on electrical installations is ensured by several groups of protective equipment.
What applies to electrical protective equipment:
- electrical protective equipment, the function of which is to prevent electric shock;
- means for collective and individual operation, protecting against electromagnetic fields and used in installations with a voltage of at least 330 kV;
- individual protection means.
PPE is designed to prevent a person from falling, damage to the organs of the respiratory system, injury to the face, head, hands. This group also includes special suits that protect against electric arcs.
From the action of electromagnetic fields, shielding devices of an individual, as well as a removable and portable type, portable grounding are used as protective objects. This also includes prohibition, warning, index posters and signs.
What means are electrical protective and protect a person from the action of current when working in electrical installations? It:
- insulating rods and pliers;
- voltage indicators;
- fixed and mobile devices and instruments indicating the presence of voltage;
- devices for safe measurements and tests;
- gloves, galoshes, rugs and coasters made of materials with dielectric properties;
- shields or screens;
- caps, covers and linings;
- individual tools with insulation (screwdrivers, pliers, etc.);
- ladders and ladders made of non-conductive material;
- posters and other warning, prohibition and guidance signs.
All insulating electrical protective equipment, depending on the degree of protection, is divided into two subgroups.
Basic and additional electrical protective equipment
The classification of electrical protective equipment involves dividing them into basic and additional.
The main electrical protective equipment includes those that provide a high degree of protection against the action of electricity and allow you to touch and work with live parts. It follows from this which insulating protective equipment is additional: they are used only in conjunction with the first category, since they cannot provide long-term and complete protection against the action of electric current.
All funds are numbered and registered and periodically subjected to inspection and/or verification.
Depending on the voltage threshold that may be in the electrical installation, both categories are divided into 2 sections.
List of electrical protective equipment:
Basic insulating electrical protective equipment | Additional insulating electrical protective equipment |
Electrical protective equipment in electrical installations up to 1000 V | |
any insulating rods | galoshes and boots |
isolation pliers | carpets and coasters made of dielectrics |
indicators of the presence and magnitude of voltage | caps, covers and linings insulating against current |
clamps for measuring electricity | ladders and ladders |
dielectric gloves | |
individual tool with non-conductive handles | |
For installations with voltages above 1000 V | |
capacitive and non-contact voltage indicators, for phasing | boots and gloves made of dielectric material |
isolation pliers | carpets and coasters |
insulating rods | ladders and ladders |
clamps for measuring current | caps and covers for insulation |
shielding devices for personal protection | voltage signaling devices |
protective devices for work under voltage |
Produced by qualified specialists using a special installation. This is a difficult process that requires certain skills. How to safely test dielectric gloves, read our separate article.
Rubber gloves are diverse in material and purpose. For example, rubber gloves will be very different.
Checking and testing terms of dielectric protective equipment
An item used for electrical protection must necessarily have a special stamp, which indicates the following parameters:
- title;
- manufacturer;
- date of manufacture;
- test period.
The last parameter is so important that in the absence of it or the end of the verification action, it is forbidden to use the tools in the work. The use of this electrical protection is a safety violation that carries a risk to life.
The first test of electrical protective equipment is carried out after the production of the product, subsequent tests after certain periods. The terms for testing electrical protective equipment are specified in GOST and TU. The same documents prescribe the conditions and time of test work, as well as the frequency of inspections, which are usually carried out more often and can be either self-diagnosis or a preliminary stage of verification. The assessment of the mechanical and electrical qualities of protective equipment is usually carried out in specialized organizations.
Below is a table that indicates the frequency of testing electrical protective equipment.
Terms of checking dielectric protective equipment | Product type | Frequency of inspections |
Every six months | Dielectric gloves | Before each use |
Ladders and ladders | Semiannually | |
Protective equipment for live repairs | ||
Every year | Voltage indicators (up to 1 kV and above 1 kV with gas discharge lamp and phasing) | |
Insulating part of the cable piercing device | ||
Insulating caps and covers | ||
Galoshes and boots made of dielectric material | ||
Hand tools with handles made of insulating material | ||
Once a quarter, but at least once a year | Measuring rod and its parts | Once a quarter |
Every 2 years | Insulating rods | Every year |
Insulating pliers | Every six months | |
Clamps for measuring current | Semiannually | |
Non-contact voltage indicators over 1 kV | Before use | |
Insulating pads hard and rubber | Once a year | |
Every 3 years | Bots | Semiannually |
Rubber caps |
Mats and coasters are not tested, but inspection is standardized for them once a year or once every 2 years, respectively. In general, a visual check of dielectric protective equipment, which includes rugs, boots, galoshes, gloves, boots, is usually carried out before each use in order to detect a violation of the integrity of the coating.
If defects were found during inspection or testing, then insulating electrical protective equipment cannot be used.
In the process of working at electrical installations, the use of protective equipment (AP) is required - items that prevent a person from falling under the negative effect of electricity. It is important to properly understand which APs should be used, what they are for, and how to maintain them in good condition, where special attention should be paid to checking and replacing.
Protective equipment against electric current
APs protect workers from the following electricity-related factors:
- electric shock - means of electrical protection;
- the negative impact of exposure to a powerful electromagnetic field - protective equipment in electrical installations, where the voltage reaches 330 kV or more;
- the need for personal protective equipment - PPE.
As can be seen from the table, funds are basic (OZS) and additional (DZS).
List of basic and additional means of electrical protection
Main insulating electrical protective funds | Additional insulating electrical protective funds |
||
---|---|---|---|
above 1000 V: | In electrical installations with voltage up to 1000V: | In electrical installations with voltage above 1000 V: | In electrous- tanovkah nap- disguise up to 1000V: |
voltage indicators | voltage indicators | insulating caps and linings | insulating caps, coatings and overlays |
insulating pliers | insulating pliers | dielectric carpets and insulating pads | dielectric carpets and insulating coasters |
insulating rods all kinds | insulating rods all kinds | dielectric gloves and boots | dielectric galoshes |
devices and fixtures for ensuring the safety of work during measurements and tests in electrical installations (voltage indicators for checking the coincidence of phases, electrical pliers, cable piercing devices, etc.) | electrical pliers, dielectric gloves, manual insulating tool | transfer and potential equalization rods | stairs attached, ladders insulating fiberglass teak |
special protective equipment, insulating devices and fixtures for work under voltage in electrical installations with a voltage of 110 kV and above (except for rods for transferring and equalizing potential) | dielectric gloves | ladders, insulating fiberglass ladders |
Means of protection against electric current
OZS are needed in the process of servicing electrical installations to create a reliable barrier when touching current-carrying elements under voltage. A distinctive feature of DZS is that they do not protect against electric shock on their own, but must be used in conjunction with OZS, the reliability of which they increase by protecting against arcing, step voltage or electric shock from conductive elements. In the figure above, in the table, OZS and DZS are in separate lists.
Special requirements are imposed on the properties of materials used for the manufacture of OZS. They have a stable dielectric characteristic. They include porcelain, bakelite, getinaks, rubber, ebonite, etc.
The quality of dielectric gloves and other products depends on which rubber is used. It is subject to the requirements of high electrical resistance and sufficient elasticity. All products have a certain service life, because over time, the quality of rubber deteriorates under the influence of the external environment, petroleum products, aggressive substances and from damage. Therefore, tests are carried out for the AP, and a certain frequency is observed here, in accordance with the established standards.
Products are manufactured for two different applications in electrical installations:
- Up to 1000 V - OZS. Not applicable for higher voltage.
- Over 1000 V - used as a DZS together with the main OZZ or when controlling switches for voltages over 1000 V. These dielectric gloves are allowed to be used as OZZ in electrical installations less than 1000 V.
Gloves are worn completely so that the bells can be closed on top of the sleeves of clothing. To do this, their width should be sufficient. Wrapping their edges is not allowed.
Gloves are made with or without a seam, from special rubber (fig. below). The fact that they are AP is indicated by the marking Ev or En. The sizes used should be sufficient to be able to put on knitted prints from below.
Dielectric gloves: a - seamless; b - single-seam
Checking products before work includes an external inspection for defects, cuts, tears, dirt and excessive moisture. All these factors significantly reduce the dielectric properties of the ZS. Gloves are checked for tightness by folding in the direction from the bell to the fingers.
To protect the used dielectric gloves from external influences, ordinary work gloves are put on from above.
During operation, gloves are periodically washed with soda, soap and other detergents, after which they must be dried.
Electronic glove test
Products are tested in the aquatic environment (fig. below). To do this, water is poured into them with an indentation from above of about 50 mm, and then immersed in a bath so that the edges remain dry. A voltage is applied to the metal surface of the bath (8) and to an electrode placed in a glove and the current value is controlled. If several products are tested, the current in each of them is controlled by switching the milliammeter.
In the event of a breakdown or when the current through the glove is above the norm, it is rejected.
Power is supplied through a high voltage transformer (1). Before it, you can additionally connect an autotransformer to control the magnitude of the test voltage.
Scheme of the device for testing dielectric gloves: 1 - high-voltage transformer; 2 – switch contacts; 3 - shunt; 4, 7 – arresters; 5 - inductive load; 6 - current device; 8 - capacity
Indications in each product are determined by a milliammeter (6) connected by contacts (2). At the same time, arresters (4) are designed to protect switched circuits. If the tested glove is pierced, the choke (5) limits the current and protects the circuit with the measuring device from overload.
The table below shows the established standards for the frequency of testing dielectric gloves and other OZZ.
Table of test parameters for AP in electrical installations
Name for- protective means | Voltage electrostatic novki, kV | Test voltage, K | duration, min. | Periodicity tests |
---|---|---|---|---|
Operational insulating bars | 10 | 40 | 5 | 1 time per 2 years |
Voltage indicators above 1000 V | Up to 10, over 10, up to 20 | 40 60 | 5 5 | 1 time per year |
Voltage indicators up to 1000 V | up to 0.5 | 1 | 1 | _-_ |
Voltage indicators for phasing | to 10 | 40 | 5 | |
Cable puncture device | to 10 | 40 | 5 | _-_ |
Insulating pads - hard | up to 0.5 up to 10 | 1 20 | 5 5 | 1 time per 2 years |
- flexible | up to 0.5 | 1 | 1 | >> |
Insulating caps on the cores off. cable | to 10 | 20 | 1 | 1 time per year |
Flexible insulating strips for live work | up to 1 | 6 | 1 | |
all voltages | 6 | 1 | 1 time in 6 months. |
Insulating rods
The device consists of three parts: insulating, working and handle. The device is used on elements with a passing current, or near them. Working elements can be clamps, tips, and other designs, depending on the purpose. The universal head is made removable to perform various operations. It securely fixes interchangeable fixtures. The bar becomes a control device after fixing a voltage indicator on it. The number of links used on the insulating part may vary. Telescopic devices are convenient, but one-piece structures are also used. The norms of the weight load on the arm are normalized and selected so that one or two people can work.
With the use of rods, insulation quality checks are made, fuses are replaced, various parts are installed, operations are performed with disconnectors, electrical parameters are measured, grounding is applied, etc.
With the help of a bar, you can free a person who has been affected by an electric current.
Devices of various types of rods and requirements for them are standardized.
On fig. a bar with a clamp is shown and all components of the device are marked.
Rods used in electrical installations: a - operational; b - portable grounding
Portable grounds contain clamps for connection to current-carrying parts or wires (fig. b). They may be removable or non-removable.
Rods are tested under high voltage applied to their insulating parts. The parameters are presented in the table above. Voltage is applied between the working part and the removable electrode, which is temporarily attached near the stop between the handle and the insulating part (Fig. a).
Boom Performance Test Diagram
The voltage value is regulated by an autotransformer installed at the input of the device (voltage regulator). The passing current is checked by a milliammeter protected from overload using a spark gap (P) (Fig. b).
Insulating pliers
With the help of insulating pliers, they replace fuses, remove linings, fences, and perform other similar work. They are made entirely of non-conductive material (up to 1000 V) or with metal jaws. Their mass allows one electrician to work.
Electrical strength tests are carried out similarly to rods. The parameters are presented in the table above.
Instead of insulating pliers, a rod can be used if a suitable work item is selected.
Electrical tongs are used to measure parameters in circuits up to 1 kV. They contain a secondary winding connected to the instrument. The high-voltage bus or wire serves as the primary. The working part is a detachable magnetic circuit with a winding and a device.
Voltage indicators
The devices are used to check the voltage in electrical installations, as well as the phasing of high-voltage equipment. Technical requirements for them are set out in GOSTs. As indicators, gas-discharge or LED lamps are used, ignited by a capacitive current passing through them. Pointers can be non-contact or with an electrode for direct contact with the bus or wire. Indication can be light, sound or combined. In this case, the signals must be clear and recognizable.
Figure (a) below shows the pointer high voltage UVNU-10 assembled. To create a working state, it is necessary to unscrew the thread, turn the working part 180 0 and screw it in again (Fig. b).
Voltage indicator UVNU-10
Tests are carried out for an isolated area and the indication voltage is checked. The frequency is regulated by the established standards (1 time per year). The insulated part is checked in the same way as the rods.
The lamp lights up when the voltage reaches 25% of the nominal.
For check led lamp voltage is applied only to the working part.
Before operation, the UVN is checked by touching the current-carrying parts with the working element for 5 seconds. For U>1000 V), dielectric gloves are required for the device.
Portable grounding
Devices are needed to protect people working on live parts of electrical installations after they have been disconnected from voltage induced or applied by mistake. Designs can be rod or rodless.
Test methods do not differ from insulating rods.
If there is no grounding rod, the insulating flexible grounding element is checked in parts. You can test it in one go by winding it into a bay.
Dielectric galoshes and boots
Dielectric footwear is an additional means of protection to OZS, as well as protection against step voltage in electrical installations or on overhead power lines.
Galoshes and boots should be worn on top of regular shoes. Outwardly, they differ from it in a not very spectacular appearance, but the main thing here is safety.
Dielectric footwear for work on electrical installations
Before using the products, it is necessary to examine them for defects: hard inclusions, delaminations, breaks, etc.
Electrical testing of shoes is carried out according to the same technology as with dielectric gloves. The norms for filling with water galoshes and bots are respectively 2 cm and 5 cm from the top edge.
Hand tool
As an OZS at electrical installations up to 1 kV, a manual insulating tool (RII) is used. It is made in two types:
- metal with full or partial electrical insulation coating (fig. below);
- entirely of electrically insulating material or with metal inserts.
Insulated coated hand tools
The insulating coating of the metal must be strong enough, resistant to moisture and oil products. The handles of pliers, wire cutters, etc. are equipped with stops that prevent the hand from touching metal parts during operation.
The tool must be inspected before each use. The protective layer must be free of defects that reduce its strength and insulating properties.
Every six months, the hand tool is inspected by a designated worker who records the examination data.
The tool is tested at a voltage of 2 kV with a time delay of 1 min, and the frequency should not be less than once a year.
Rules for the use of SZ
- Personnel in electrical installations who are provided with the required protective equipment must be appropriately trained and able to handle them to ensure safety.
- APs are marked with the designation of the manufacturer, type of product, production date, and a stamp on electrical tests is required.
- Objects and brigades on departure are completed with inventory AP, as required by the norms and operating conditions. APs are also issued to employees individually. Their distribution is recorded in the lists, which are approved by the head of the electrical facilities. They indicate the storage locations of the AP.
- Unsuitable protective equipment or past service life are subject to withdrawal with a note in the accounting journal. The entry must conform to a certain form.
- APs must be properly operated by workers. They are required to monitor the serviceability of inventory and control the timing of verification.
Expired APs are strictly prohibited! AP may only be used for the purposes specified in the instructions. It is especially necessary to monitor the correspondence between the voltages of means and electrical installations.
- OZS can only be used outdoors in dry weather. At high humidity, only special APs can be used.
- Where there is a limit ring, it is allowed to hold the AP during operation only by the handle, up to the limiter.
Checking the status of the AP
- All operated APs, with the exception of some DZS, have a numbering, which is done by paint, knocking out on parts or by attaching tags.
- There is a frequency of inspection (1 time in half a year, and ground rods - 1 time in three months) of the state of the AP by a designated contractor, who must record the data of the verification inspection in writing.
- Received into operation, new APs are tested (if the standards are established for this) and stamps are placed on the products that establish the terms of use for the prescribed period. If the result is negative, the stamp is crossed out with paint.
- The results of the checks are recorded in the logs, and separate protocols are drawn up at the third-party APs.
It is possible to store and move the AP only under the conditions of their reliable protection from damage, dirt and moisture. It is forbidden to store them together with tools. It is also not allowed to hit the AP with various aggressive substances and oil products.
When transported by mobile teams, protective equipment is in covers, boxes or bags.
AP test rules
- The frequency of testing of the AP is always maintained, but additional extraordinary tests are carried out (after repair, when replacing faulty parts, after an impact or fall, if a malfunction is suspected).
- Checking protective equipment can only be carried out if there is no damage, the insulation is in a normal state, if there is a factory marking, number, and completeness. The surface of the insulation must be free from visible defects. Structurally, the devices are made so that they can be easily cleaned or prevent dust and moisture from entering inside. The remarks must be eliminated, otherwise the AP will not be allowed to test for dielectric strength.
- When checking the insulation, the voltage can be raised to 1/3 of the nominal voltage quickly, then smoothly. After reaching the norm and holding the time interval, the voltage decreases by 1/3 of the test voltage or completely, and then turns off. There are standards for the current passing through the insulation for each material.
- The breakdown is determined visually or according to the instruments. Then the product is rejected.
- ZS after shutdown of the installation are checked for the absence of overheating.
Video about SZ
About personnel protection equipment and their standardization is described in this video.
For the safety of workers at electrical installations, APs are used; over time, they lose their properties. Therefore, there is a predetermined frequency of regular and extraordinary inspections of the AP, so that if their performance deteriorates, they can be removed in time and replaced with new ones. When the correct organization of the use and verification of protective equipment is carried out, they provide the necessary electrical safety of work.
GOST 20493-2001
INTERSTATE STANDARD
VOLTAGE INDICATORS
GENERAL SPECIFICATIONS
INTERSTATE COUNCIL
ON STANDARDIZATION, METROLOGY AND CERTIFICATION
Minsk
Foreword
1 DEVELOPED by the Special Design and Technology Bureau for High-Voltage and Cryogenic Equipment (SKTB VKT) - a branch of OAO Mosenergo
INTRODUCED by Gosstandart of Russia
2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 19 dated May 24, 2001)
State name |
Name of the national standardization body |
The Republic of Azerbaijan |
Azgosstandart |
Republic of Armenia |
Armstate standard |
Republic of Belarus |
State Standard of the Republic of Belarus |
The Republic of Kazakhstan |
State Standard of the Republic of Kazakhstan |
Republic of Kyrgyzstan |
Kyrgyzstandart |
The Republic of Moldova |
Moldovastandard |
Russian Federation |
Gosstandart of Russia |
The Republic of Tajikistan |
Tajikstandart |
Turkmenistan |
Main State Service "Turkmenstandartlary" |
The Republic of Uzbekistan |
Uzgosstandart |
3 Decree of the State Committee of the Russian Federation for Standardization and Metrology dated December 19, 2002 No. 495-st interstate standard GOST 20493-2001 entered into force directly as the state standard of the Russian Federation on January 1, 2004.
4 INSTEAD OF GOST 20493-90
VOLTAGE INDICATORS
General specifications
Voltage detectors.
General specifications
the dateintroductions 2004-01-01
1 area of use
This standard applies to voltage indicators used as the main electrical protective equipment in electrical installations of direct and alternating current with a voltage of up to 1000 V and electrical installations of alternating current with a voltage of more than 1000 V up to 220 kV inclusive of the industrial frequency of the climatic version UHL category 1.1 according to GOST 15150, operating with direct contact to current-carrying parts of electrical installations (contact).
The standard does not apply to voltage meters intended for operation in an environment containing conductive dust and aggressive gases of high concentration, as well as voltage meters designed to operate in the rain and during a thunderstorm.
2 Normative references
This standard uses references to the following standards:
For pointers over 1000 V
Bending test
For pointers over 1000 V
Checking the electrical resistance of the insulation of the charger
For all pointers
Climate test
For all pointers
Mechanical Tests
For all pointers
Note - In the table, the "+" sign means that the tests are being carried out.
7.5 Periodic tests are carried out on voltage indicators that have passed acceptance tests.
7.6 Periodic tests should be carried out at least once every two years on at least 5 samples of voltage indicators.
7.7 Type tests should be carried out on at least 5 samples of voltage indicators.
7.8 During type and periodic tests, all parameters and characteristics established by this standard are checked in accordance with the table . The scope and methods of additional tests should be indicated in the regulatory documents (ND) for the voltage indicator.
7.9 If during type or periodic tests it is found that at least one sample does not comply with the requirements of one of the paragraphs of this standard, as well as ND, retests are carried out on a double number of samples.
In the event of negative results of repeated tests, the release and sale of the released products is suspended until the causes of the non-compliance are eliminated. Shipment of indicators is resumed only after receiving satisfactory test results.
7.10 The results of periodic and type tests must be documented.
8 Control methods
8.1 Visual control of voltage indicators consists in checking their serviceability, completeness, packaging, marking, the presence of corrosion protection, the condition of the insulating surfaces, the presence of a restrictive ring (stop) and accompanying documents.
8.2 Checking the voltage indicators for compliance with the working drawings should be carried out using a measuring tool that provides the accuracy specified in these drawings.
8.3 The roughness of the machined surfaces should be checked using a profilometer or an optical indicator.
Checking the protective coatings of metal parts should be carried out in accordance with GOST 9.302, the rate of voltage rise to 1/3 of the test voltage can be arbitrary. A further increase in voltage should be smooth and fast, but allowing, at a voltage of more than 3/4 of the test voltage, to read the readings of the measuring device. When the required voltage value is reached after exposure for a specified time, it must be quickly reduced to zero or, at a value equal to 1/3 or less than the test value, it must be turned off.
8.7 Checking voltage indicators for resistance to mechanical stress should be carried out according to GOST 16962.2 (Method 104-1) or by transporting signs in containers by car on dirt roads - for a distance of 50 km at an average speed of 20 km/h or on asphalt roads - for a distance of 200 km at an average speed of 50 km/h with subsequent verification their performance.
8.8 Checking the electrical resistance of the insulation of the charger should be carried out according to GOST 2933 . Wherein Charger connect to the voltage indicator, wrap its case with foil, as well as the working and indicator parts of the voltage indicator, connect the contacts of the power plug to each other, and connect a 1000 V megger between one of the contacts and the foil.
If the batteries are charged by removing them from the voltage indicator with subsequent installation in the charger, then the case of the charger with the batteries installed in it is wrapped with foil.
If there is an isolation transformer in the charger, the case is wrapped with foil, to which the contacts of the connector are attached, which serves to connect to the voltage indicator.
8.9 Voltage indicators up to 1000 V
8.9.1 The pulse repetition rate of the light and sound signals is checked by applying the minimum operating voltage to the contacts - tips of the voltage indicator.
8.9.2 To check the indication voltage and the serviceability of the voltage indicators, the voltage from the test facility is applied to the contacts - tips of the two-pole indicator, to the tip contact and the contact on the body of the single-pole indicator.
8.9.3 Checking the voltage at the contacts - tips of multifunctional voltage indicators in the continuity test mode is carried out using a voltmeter.
8.9.4 The value of the current flowing through the voltage indicator at the highest operating voltage is determined using a milliammeter connected in series with the indicator.
8.9.5 To test the insulation of a two-pole voltage indicator with increased voltage, both cases are wrapped in foil. The foil on both cases is connected with a wire. One terminal of the test set is earthed. The test voltage is applied to the tips of both housings of the voltage indicator. The second (grounded) wire is connected to the foil on the body, and the connecting wire is lowered into a grounded vessel with water so that the water covers it, not reaching the handles 10 mm.
For single-pole voltage indicators, the case is wrapped with foil along the entire length up to the limit stop. One wire from the test set is connected to the tip, and the second (grounded) to the foil.
8.9.6 Voltage indicators should be considered as having passed the tests in the absence of breakdown, overlap on the insulation surface, increase in the values of current and voltage indication above the rated values. The presence of breakdown, overlap on the surface of the insulation is established according to the readings of measuring instruments and visually.
8.10 Voltage indicators over 1000 V
8.10.1 The time until the first signal appears is measured using a stopwatch. Determination of the time of appearance of the first signal should be carried out first.
8.10.2 Time to the appearance of the first signal and the frequency of the pulses of the light and sound signalfishing is checked by applying the minimum phase operating voltage to the indicator. The distance from the pointer to grounded objects when checking the time of the appearance of the first signal and the pulse frequency must be at least 2 m.
8.10.3 Determining the indication voltage - according to .
8.10.4 When checking the voltage indicator for the absence of indication from the influence of neighboring circuits, voltage is applied to a bus (wire) 2 m long, the indicator is connected to an insulated bus (wire) of the same length, located parallel to the first bus at a distance specified in .
8.10.5 When checking the electrical strength of the working part, the test voltage is applied to the tip contact and points located at distances from each other equal to the smallest distance in the light from current-carrying parts to grounded structures and parts of buildings established by the rules [ ].
8.10.6 When checking the electrical strength of an insulating part, it is allowed to test it in parts. In this case, the insulating part is divided into sections, to which a part of the specified total test voltage is applied, proportional to the length and increased by 20%.
8.10.7 Voltage indicators should be considered as having passed the test in the absence of breakdown, overlapping on the insulation surface, indication from the influence of neighboring circuits, increase in the indication voltage value above the rated value.
8.10.8 When testing for bending, the stress indicator is installed horizontally and fixed at two points: at the end of the handle and the restrictive ring.
8.10.9 The stress gauges should be considered to have passed the test if the deflection under the action of the mass of the working part, measured at the end, does not exceed 10% of the length involved in the test, and also in the absence of residual deformations, cracks and loosening of fasteners.
9 Transportation and storage
9.1 Transportation of voltage gauges is carried out by any mode of transport in covered vehicles in accordance with the rules for the carriage of goods in force for this type of transport.
9.2 The conditions of storage and transportation of voltage indicators in terms of the impact of climatic factors of the external environment must comply with group 5 according to GOST 15150.
In terms of the impact of mechanical factors, the conditions of transportation must comply with group C in accordance with GOST 23216.
9.3 Storage of pointers should be carried out in a packed form; storage group 2 GOST 15150 in the absence of exposure to acids, alkalis and other aggressive substances, as well as organic solvents.
10 Operating instructions
10.1 The operation of voltage indicators must be carried out in accordance with the rules [ ], [ ] and a passport to a pointer of a specific type.
10.2 Repair of voltage indicators is carried out by specialized enterprises or the manufacturer.
11 manufacturer's warranty
11.1 The manufacturer guarantees the compliance of the voltage indicator with the requirements of this standard, subject to the conditions of storage, operation and transportation.
11.2 Warranty period of operation of the voltage indicator - a year from the date of commissioning.
11.3 The service life of voltage indicators (except for an autonomous power source) is at least five years.
APPENDIX A
(reference)
Bibliography
Rules for the installation of electrical installations. Moscow: Energoatomizdat, 1985
Safety regulations for the operation of electrical installations. Moscow: Energoatomizdat, 1987, approved. Presidium of the Central Committee of Trade Unions of Workers at Power Plants and the Electrical Industry, Office for Safety and Industrial Sanitation of the USSR Ministry of Energy, 1985
Keywords: voltage indicators, specifications
To check the presence or absence of voltage in electrical installations up to 1000 V, two types of indicators are used:
bipolar - working with the flow of active current;
single-pole - operating with capacitive current.
Two-pole pointers are designed for electrical installations of alternating and direct current, and single-pole - for electrical installations of alternating current.
Two-pole pointers consist of two housings containing elements electrical circuit. The elements of the electrical circuit are interconnected by a flexible wire that does not lose elasticity at low temperatures, at least 1 m long.
The electrical circuit of a two-pole pointer with visual indication may contain a pointer-type device or a digital sign-synthesizing system (with a small-sized power supply for the indicating scale). Pointers of this type can be used for voltages from 0 to 1000 V.
The electrical circuit of a single-pole voltage indicator must contain an indication element with an additional resistor, a tip contact and a contact on the end (side) part of the housing, with which the operator's hand comes into contact.
The length of the uninsulated part of the contacts - tips should not exceed 5 mm. Tip contacts must be rigidly fixed and must not move along the axis.
Operational tests of voltage indicators up to 1000 V consist in determining the indication voltage, checking the circuit with increased voltage, measuring the current flowing through the indicator at the highest operating voltage, and testing insulation with increased voltage.
To check the indication voltage for a two-pole pointer, the voltage from the test setup is applied to the contacts - tips, for a single-pole pointer - to the contact - tip and the contact on the end (side) part of the housing.
The indication voltage of voltage indicators up to 1000 V should not exceed 50 V.
To check the circuit for a two-pole pointer, the voltage from the test setup is applied to the contacts - tips, for a single-pole pointer - to the contact - tip and the contact on the end (side) part in accordance with the diagrams in Fig. 5.
The test voltage when checking the circuit must exceed the highest value of the operating voltage by at least 10%. The duration of the test is 1 minute.
The value of the current flowing through the pointer at the highest value of the operating voltage must not exceed:
0.6 mA for a single-pole voltage indicator;
10 mA for a two-pole voltage indicator with elements providing visual or visual-acoustic signal indication;
for voltage indicators with an incandescent lamp up to 10 W with a voltage of 220 V, the current value is determined by the power of the lamp.
The current value is measured using an ammeter connected in series with the pointer in accordance with the diagram in fig. 6.
To test the insulation of voltage indicators with increased voltage, for two-pole indicators, both insulating cases are wrapped in foil, and the connecting wire is lowered into a grounded vessel so that water closes the wire, not reaching the handle by 9 - 10 mm. One wire from the test setup is connected to the contacts - tips, the second, grounded, to the foil and lowered into the water in accordance with Fig. 7.
For single-pole voltage indicators, the insulating housing is wrapped with foil along the entire length up to the limit stop. A gap of at least 10 mm is left between the foil and the contact on the end of the housing. One wire from the test setup is connected to the contact - the tip, the second, grounded - to the foil.
The insulation of voltage indicators up to 500 V must withstand a voltage of 1 kV, and voltage indicators above 500 V - 2 kV. The duration of the test is 1 minute.
Rice. 5 Schemes for testing a single-pole voltage indicator up to 1 kV.
Rice. 6 Test schemes for a two-pole voltage indicator up to 1 kV.
Rice. 7 Schemes for testing the insulation of a two-pole voltage indicator up to 1 kV.
Voltage indicators for phase matching
Pointers are designed to check the phase coincidence on overhead and cable lines, transformers and other electrical installations from 3 to 110 kV.
Pointers are two-pole devices of the light-signal type, operating in direct contact with live parts of electrical installations under voltage.
Pointers consist of two tubular cases made of electrically insulating material containing working, insulating parts and handles. Elements of the electrical circuit (contact electrodes, gas-discharge indicator lamp and corresponding electronic components) are mounted in the working parts of the pointer itself and the tube with additional resistance, connected by a flexible wire with reinforced insulation. The tube with additional resistance is arranged in the same way as a conventional voltage indicator, but instead of a capacitor and a gas-discharge lamp, heat-resistant resistances are inserted inside.
The design of the working parts of the indicators should exclude the possibility of breakdown and flashover with simultaneous contact with current-carrying and grounded parts of electrical installations.
During operational tests, the indicators are checked according to the schemes of consonant and counter switching, the electrical strength of the working and insulating parts and the connecting wire is checked.
When checking the pointer according to the consonant switching circuit, both contact electrodes are connected to the high-voltage output of the transformer according to the circuit in fig. eight.
When checking the indicator according to the counter-connection scheme, one of the contact electrodes is connected to the high-voltage output of the transformer, and the second to the grounded output of the transformer according to the diagram in Fig. 9.
During the test, the indicator voltage is fixed, the values of which, depending on the circuit, are given in Table 3.
When checking the electrical strength of the longitudinal insulation of the working parts, the test voltage is applied to the contact electrode and the threaded connector element for 1 minute. Tests are made according to the scheme of fig. 2.
In this case, the test voltages must have the following values:
12 kV - for an indicator with voltage up to 10 kV;
70 kV - for an indicator with a voltage of 35 kV;
100 kV - for an indicator with a voltage of 110 kV.
When checking the electrical strength of the longitudinal insulation of the insulating parts, the test voltage is applied for 5 minutes to the metal connector and the wire bandage applied at the restrictive ring. Tests are made according to the scheme of fig. 3.
In this case, the test voltages must have the following values:
40 kV - for an indicator with voltage up to 10 kV;
105 kV - for an indicator with a voltage of 35 kV;
190 kV - for an indicator with a voltage of 110 kV.
A flexible wire is tested with a voltage of 20 kV for 1 minute for indicators up to 20 kV, for indicators of 35-110 kV - 50 kV for 1 minute.
The wire is lowered into a bath of water so that the distance between the wire termination point and the water level is within 60-70 mm for indicators up to 20 kV and 160-180 mm for indicators up to 35-110 kV. Voltage is applied to a contact electrode immersed in water.
In operation, mechanical tests of pointers are not carried out.
Rice. 8 Scheme of consonant inclusion of the voltage indicator.
Rice. 9 Scheme of counter switching on the voltage indicator.
Rice. 10 Scheme of testing the connecting wire of the voltage indicator.
Cable puncture devices
Cable piercing devices are designed to indicate the absence of voltage on the repaired cable up to 10 kV before cutting it by piercing the cable along the diameter and shorting all the conductors of different phases to each other and to the ground.
The devices include a working body, a grounding device, an insulating rod and a drive.
The grounding device includes a grounding rod with a grounding conductor and clamps.
The length of the insulating part of the device must be at least 230 mm.
The cross section of the ground contact must be at least 25 mm².
During operational tests, the operability of the device is checked by puncturing a sample of the ABASHV 3 x 240 type cable, and in mechanical type puncture devices, in addition, the force applied to the drive belt is measured.
During operational tests, the insulating parts of the devices (insulating rod or insulating insert of the electric drive) are tested with an increased voltage of 40 kV for 5 minutes.
The test voltage is applied to the insulating part of the rod or to the metal flange of the electric drive and a special terminal.
Dielectric rubber gloves
Gloves are designed to protect hands from electric shock when working in electrical installations up to 1000 V as the main electrical protective equipment, and in electrical installations above 1000 V - as an additional one.
In electrical installations, it is allowed to use only gloves marked with protective properties EN (for protection against electric current with voltage up to 1000 V), EV (for protection against electric current with voltage above 1000 V).
The length of the gloves must be at least 350 mm.
In operation, only electrical testing of gloves is carried out.
Once every 6 months, gloves must be tested with an increased voltage of 6 kV for 1 minute, the current through the glove should not exceed 6 mA.
When testing, dielectric gloves are immersed in a metal vessel with water at a temperature of 25 + 10 ° C, which is also poured into these products. The water level both outside and inside the products must be 50 mm below the top edge of the gloves.
The protruding edges of the gloves must be dry. One terminal of the test transformer is connected to the vessel, the other is grounded. An electrode connected to ground through a milliammeter is lowered inside the gloves. The product is rejected if the current passing through it exceeds the norm or sharp fluctuations of the milliammeter needle occur.
In the event of a breakdown, the defective product or the entire installation is turned off.
Fig.11. Schematic diagram of testing dielectric gloves, overshoes and galoshes.
Boots, rubber dielectric galoshes
Special dielectric footwear (glued overshoes, rubber glued or shaped boots in tropical design) is an additional electrical protective equipment when working in closed, and in the absence of precipitation - in open electrical installations. In addition, dielectric boots and galoshes protect workers from step voltage.
Shoes are used:
galoshes - at voltages up to 1000 V;
boots - at all voltages.
According to the protective properties of shoes denote:
En - rubber glued galoshes;
Ev - rubber glued and molded boots.
The height of the bot must be at least 160 mm.
In operation, dielectric galoshes are tested with a voltage of 3.5 kV, and boots with a voltage of 15 kV for 1 minute. The currents flowing through the products should be no more than 2 mA for galoshes and 7.5 mA for boots.
When testing, the water level both outside and inside horizontally installed products should be 20 mm below the sides of the galoshes and 50 mm below the edge of the lowered lapels of the boots.
Tests are carried out according to the scheme of Fig. eleven.
At the end of the tests, the products are dried.
Dielectric rubber carpets and insulating pads
Dielectric rubber carpets and insulating stands are used as additional electrical protective equipment in electrical installations up to and above 1000V.
Carpets are used in closed electrical installations of all voltages, except for particularly damp rooms, and in open electrical installations in dry weather.
Stands are used in damp and polluted rooms.
Carpets are manufactured in accordance with the requirements of GOST 4997-75, depending on the purpose and operating conditions of the following two groups:
1st group - normal execution;
2nd group - oil and petrol resistant.
Carpets (recommended to use at least 50 x 100 cm) are made in the following sizes:
length from 500 to 1000 mm;
over 1000 to 8000 mm;
width from 500 to 1200 mm;
6 + 1 mm thick.
Carpets must have a corrugated front surface and be of one color.
The insulating support consists of a flooring fixed on support insulators with a height of at least 70 mm. It is recommended to use insulators of the CH-6 type, produced specifically for the manufacture of stands.
Flooring with a size of at least 500 x 500 mm should be made of wooden planks without knots and slant, planed from well-dried wood. The gaps between the bars should not exceed 30 mm. Solid decks are not recommended, as they make it difficult to check that there is no accidental shunting of the insulators. The flooring must be painted on all sides.
Insulating supports must be strong and stable. In the case of using removable insulators, their connection to the flooring must exclude the possibility of slipping of the flooring. To eliminate the possibility of overturning of the insulating support, the edges of the flooring should not protrude beyond the supporting surface of the insulators.
In operation, carpets and coasters are not tested. They are rejected during inspections. Carpets should be cleaned of dirt and inspected at least once every 6 months. If defects are found in the form of punctures, tears, cracks, etc. they should be replaced with new ones.
The supports are inspected once every 3 years for the absence of violations of the integrity of the support insulators, kinks, weakening of the connection between the individual parts of the flooring. If these defects are found, they are rejected, and after the defects are eliminated, they are tested according to the standards of acceptance tests.
23.1. Testing of voltage indicators up to 1000 V
23.1.1. Electrical operational tests of voltage indicators up to 1000 V inclusive must be carried out to the extent and in compliance with the following requirements:
Determine the threshold voltage, - which must comply with the requirements of paragraph 8.2.8 of these Rules;
Measure the current flowing through the pointer at the highest operating voltage - which must comply with the requirements of paragraph 8.2.5 of these Rules;
Check the circuit with increased voltage, - which must comply with the requirements of paragraph 8.2.4 of these Rules;
Carry out an insulation test with increased voltage, namely: for single-pole voltage indicators - the insulating case of the indicator along the entire length to the limit stop must be wrapped in foil, leaving a gap of up to 10 mm between the foil and the contact on the end of the case; one wire from the test setup must be connected to the tip, and the second, grounded, to the foil; for two-pole voltage indicators - both insulating cases of the indicator must be wrapped with foil, and the connecting wire must be immersed in a vessel with water so that the water covers the wire, not reaching the handles by 9-10 mm; one wire from the test setup must be connected to the tips, and the second, grounded, to the foil and immersed in water, as shown in Figure 2.
The current must be measured using a milliammeter connected in series with a voltage indicator.
23.1.2. When carrying out operational tests of voltage indicators up to 1000 V in order to determine the voltage of the response threshold, check the electrical circuit with increased voltage, measure the current, the voltage from the test installation must be applied:
To tip contacts
For bipolar voltage indicators;
To the contact tip and the contact on the end (side) part of the housing - for single-pole voltage indicators.
23.2. Testing voltage indicators above 1000 V with a gas discharge lamp
23.2.1. Mechanical tests of voltage indicators above 1000 V with a gas discharge lamp during operation are not carried out.
23.2.2. Electrical performance tests of voltage indicators above 1000 V must be carried out to the extent and in compliance with the following requirements:
Determine the threshold voltage of the pointer, - which must comply with the requirements of paragraph 8.3.4 of these Rules;
Determine the pointer response time - which must comply with the requirements of paragraph 8.1.12 of these Rules;
Test the working part of the indicator with increased voltage, - which (working part) must comply with the requirements of paragraph 8.3.5 of these Rules;
Test the insulating part of the indicator with increased voltage, - which (the insulating part) must comply with the requirements of paragraph 8.3.6 of these Rules.
When checking the pointers, it is necessary to record the voltage values of the response threshold, which must comply with the requirements of paragraph 9.2.3 of these Rules.
23.2.3. When conducting electrical tests of voltage indicators above 1000 V, to determine the response threshold, response time, testing the working and insulating parts of the indicator with increased voltage, the voltage from the test installation must be applied:
To the tip contact and the connection element of the working and insulating parts - for a detachable contact type voltage indicator;
To a tip contact and a temporary electrode (conductive bandage) superimposed on the border of the working and insulating parts - for a one-piece voltage indicator.
23.2.4. During the operation of voltage indicators above 1000 V, do not carry out:
Mechanical tests;
Electrical tests of transverse insulation;
Testing of the working part of voltage indicators from 35 to 220 kV.
23.3. Testing voltage indicators for phasing
23.3.1. Electrical operational tests of voltage indicators for phasing must be carried out in the following scope:
Perform a check of pointers according to the schemes of coincidence and counter-connection of phases;
Test the working, insulating parts, as well as the connecting wire with increased voltage.
23.3.2. Electrical performance tests of voltage indicators for phasing should be carried out according to the following schemes:
Phase coincidence - if both contact electrodes of the indicator are connected to a high-voltage transformer in accordance with Figure 3, a;
Counter switching of phases, - if any of the contact electrodes of the indicator is connected to the transformer terminals in accordance with Figure 3, b;
When checking the pointers, it is necessary to record the voltage values of the response threshold, which must comply with the requirements of paragraph 9.2.3 of these Rules.
23.3.3. When conducting electrical tests of the working and insulating parts of the voltage indicator for phasing, the values of the test voltage must be selected in accordance with the requirements of paragraphs 9.2.4 and 9.2.5 of these Rules and applied:
To the contact electrode and to the connection element of the working and insulating parts - in the case of testing the longitudinal insulation of the working parts of the indicator;
To a metal connection and to an electrically conductive bandage applied near the restrictive ring - in the case of testing the longitudinal insulation of the insulating parts of the indicator.
23.3.4. Checking the insulation of the flexible connecting wire of voltage indicators for phasing must be carried out according to the following method:
For pointers up to 20 kV - the connecting wire must be immersed in a bath of water so that the distance between the metal tips of the connection with the pole and the water level in the bath is from 60 to 70 mm, and apply a test voltage to the contact electrode and to the body of the metal bath;
For pointers from 35 to 110 kV, the connecting wire, separately from the pointer, must be immersed in a bath of water so that the water level is 50 mm below the metal lugs, and one of the transformer leads is connected to the metal lugs of the flexible wire, and the other to body of a metal bath or to an electrode immersed in water. The value of the test voltage and the duration of the test of the connecting wire must comply with the requirements of paragraph 9.2.6 of these Rules.