Modernization of equipment for outdoor switchgear circuits 110, 220 kV. Application of energy-saving equipment

Lecture 9.

DISCLOSURE OF INFORMATION ABOUT CASH FLOW IN ACCOUNTING REPORTS

Organizations prepare a Movement Report Money (form No. 4 of the annual report).

In accordance with PBU 3/2006 Information on exchange rate differences is disclosed as part of the financial statements.

Exchange differences are reflected in accounting separately from other types of income and expenses of the organization, including financial results from transactions with foreign currency.

IN financial statements The amount of exchange rate differences is revealed:

Formed as a result of operations of recalculation of the value of assets and liabilities expressed in foreign currency, subject to payment in foreign currency;

Resulting from operations of recalculation of the value of assets and liabilities expressed in foreign currency, payable in rubles;

Credited to accounts accounting, other than the financial performance account of the organization.

In addition, the reporting provides the official exchange rate of foreign currency to the ruble, established by the Central Bank of the Russian Federation, as of the reporting date. If, for the recalculation of the value of assets or liabilities expressed in foreign currency and payable in rubles, a different rate is established by law or by agreement of the parties, then such rate is disclosed in the financial statements.

OJSC "Uralelektrotyazhmash". The plant, commissioned in 1934, today is Uralelectrotyazhmash OJSC (UETM OJSC) - the largest enterprise in Russia producing electrical equipment for the generation, transmission, distribution and consumption of energy. It produces more than 800 types of products for more than 2,500 Customers in Russia and 60 countries around the world.

The production program includes:

High qualifications and experience of personnel, wide production and technological capabilities provide JSC UETM with a leading position in the electrical industry.

The company's products are successfully used on four continents of the world in climatic conditions from the tropics to the far north.

Since 1996, OJSC Uralelectrotyazhmash has been part of the Energomash corporation, Moscow.

The first products since the plant was launched in 1934 were high-voltage equipment, which today is the leading branch of production at the enterprise. During its operation, the plant produced more than 500 thousand switches various types in the voltage range from 600 V to 1150 kV.

Constantly updated and improved manufacturing program for SF6 high-voltage equipment includes:

· SF6 circuit breakers for voltages of 110, 220, 330 and 500 kV, equipped with pneumatic drives (VGU series);

· gas-insulated column switches new generation for voltages of 110 and 220 kV, equipped with autonomous spring drives (VGT series);

· SF6 tank circuit breakers for voltage 110 kV, breaking current 40 kA, equipped with built-in current transformers and autonomous spring drives (VEB series);

· SF6 tank switches for voltage 35 kV, breaking current 12.5 kA, equipped with built-in current transformers and electromagnetic drives (VGB series, modifications VGBE and VGBEP).

SF6 circuit breakers for voltage 110, 220 kV VGU series. SF6 gas switches of the VGUG series are designed for switching electrical circuits during operating and emergency modes in three-phase networks alternating current with a grounded neutral for a rated voltage of 220 kV. SF6 gas is used as an arc extinguishing and insulating medium.

The switches have an autonomous hydraulic drive type PGV-12A1T, TU 3414-010-48316876-2001. The switch complies with GOST 687 and has a certificate of conformity ROSS RU.ME27.B00983. Specifications on the switches are agreed with RAO UES of Russia:

Values ​​of climatic factors external environment- according to GOST 15150 and GOST 15543.1 for climatic version U1, in this case:

· installation height above sea level up to 1000 m,

· operating ambient temperature ranges from minus 45°C to plus 40°C.

The switch is suitable for operation under the following conditions:

· ice crust thickness during icy conditions - no more than 20 mm,

· wind speed in the presence of ice - no more than 15 m/s,

· wind speed in the absence of ice - no more than 40 m/s,

· permissible tension of wires in the horizontal plane applied to the terminals of the switch pole is no more than 1500 N.

The environment is non-explosive. The content of corrosive agents is in accordance with GOST 15150 (for type II atmosphere).

The main technical data of the switches are given in Table 3.1.

Table 3.1. Main technical characteristics of VGU series switches

Service life before average repair is 12 years.

Service life of at least 25 years.

The warranty period from the date of putting the switch into operation is 2 years with operating hours not exceeding the resource values ​​for mechanical or switching resistance.

The switch is a set of 3 poles that are not mechanically connected to each other and a distribution cabinet.

Each pole includes an arc extinguishing device with capacitors for uniform voltage distribution, a support column of porcelain insulators mounted on a hydraulically driven base. The hydraulic drive operates the switch. The connection between the drive and the contacts of the arc extinguishing device is carried out through an insulating rod passing inside the support insulator. Each pole is equipped with a SF6 gas density indicator to indicate when the SF6 gas pressure is decreasing.

IN distribution cabinet elements of the electrical part of the control circuits for the switch and the hydraulic pump drive unit are located. The hydraulically driven plinth and distribution cabinet are equipped with main and anti-condensation heating and a system automatic control main heating.

An autonomous hydraulic drive ensures the operation of the switch poles in simple “O” and “B” operations and in complex cycles. The drive has automatic system control of a hydraulic pump unit for pumping oil into the system high pressure, which allows you to constantly maintain the level of stored energy. The drive has counters for the number of “on-off” operations.

Overall dimensions of poles SF6 circuit breakers VGUG series are shown in Figure 3.1.

SF6 circuit breakers for voltage 110, 220 kV VGT series. The switches are designed for switching electrical circuits in normal and emergency modes, as well as operating in automatic reclosure cycles in three-phase alternating current networks with a frequency of 50 Hz and a rated voltage of 110 and 220 kV.

The switches are manufactured in climatic versions U and HL*, placement category 1 GOST 15150-69 and GOST 15543.1. They are designed for use in open and closed distribution devices in areas with temperate and cold climates (minus 55°C) under the following conditions:

· environment- non-explosive, not containing aggressive gases and vapors in concentrations that destroy metals and insulation. Content of corrosive agents according to GOST 15150 (for type II atmosphere);

· the upper operating value of the air temperature surrounding the switch is 40°C;

· the lower operating value of the air temperature surrounding the switch is: for version U1 - minus 45 ° C when filling the switch with SF6 gas, for version KHL 1 * - minus 55 ° C when filling the switch with a gas mixture (SF6 gas and CF4 tetrafluoromethane );

· relative air humidity: at a temperature of +20°C<80%, при температуре +25°C <100%;

· in case of ice with an ice crust thickness of up to 20 mm and wind speed of up to 15 m/s, and in the absence of ice - with wind speed of up to 40 m/s;

· installation height above sea level is not more than 1000 m;

· seismicity - up to 9 points on the MSK-64 scale (220 kV switches must be installed on foundation racks (concrete supports) having C35 piles with a cross section of 35x35 cm);

· tension of wires in the horizontal direction - no more than 1000 N (100 kGs).

Upon request, it is possible to supply it in climatic version T1 (upper operating air temperature +55°C).

SF6 circuit breakers comply with the requirements of GOST 687-78 "AC circuit breakers for voltages over 1000 V. General technical conditions" and technical specifications TU16-2000 2BP.029.001 TU, agreed with RAO "UES of Russia", have a certificate of conformity No. ROSS RU.ME25.B01020.

Main advantages:

· reduced effort to operate the switch. The energy required to extinguish short-circuit currents is partially used from the arc itself, which significantly reduces the operation of the drive and increases reliability;

· use of double seals in connections, as well as a “liquid seal” in the movable shaft seal unit. The natural level of leaks - no more than 0.5% per year - is confirmed by testing each switch at the manufacturer using methods used in space technology;

· modern technological and design solutions and the use of reliable components, including high-strength insulators from foreign companies.

· high factory readiness, simple and quick installation and commissioning;

· high corrosion resistance of coatings used for steel structures of the circuit breaker;

· high switching resource specified for each pole (clause 3.3), exceeding by 2-3 times the switching resource of the best foreign analogues (per each pole), combined with high mechanical resource, increased service life seals and components provide, under normal operating conditions, no less than a 25-year service life before the first repair;

· maintaining the electrical strength of the switch insulation at a voltage equal to 1.15 of the highest phase voltage in the event of loss of excess gas pressure in the switch;

· shutdown of capacitive currents without repeated breakdowns, low overvoltages.

· low noise level when activated (meets high environmental requirements);

· low dynamic loads on foundation supports;

· full interchangeability (in terms of connecting and installation dimensions) with low-oil circuit breakers of the VMT series.

The main technical data of VGT series circuit breakers are given in Table 3.2.

Table 3.2. Basic specifications VGT series circuit breakers

The number of shutdown operations allowed for each pole of the circuit breaker without inspection and repair of arc extinguishing devices (resource for switching resistance) is:

· for currents in the range of over 60 to 100% of the rated shutdown current - 20 operations (thus, for a three-pole circuit breaker, the total switching resource in this current range is 60 operations);

· for currents in the range of over 30 to 60% of the rated shutdown current - 50 operations;

· at operating currents equal to the rated current - 5000 operations “switch on - arbitrary pause - shutdown”.

The permissible number of switching operations for short-circuit currents should be no more than 50% of the permissible number of switching operations; the permissible number of switching operations at load currents is equal to the permissible number of switching operations.

The switches have the following reliability and durability indicators:

· resource for mechanical resistance before the first repair - 10,000 cycles “switch on - arbitrary pause - shutdown” (B - t n - O);

· service life before the first repair is at least 25 years, if before this period the resources for mechanical or switching resistance have not been exhausted;

· service life - at least 40 years.

Switches of the VGT series belong to high-voltage electrical switching devices, in which the quenching and insulating medium is: for version U1 - SF6 gas, and for version HL1* - a mixture of gases (SF6 gas + tetrafluoromethane CF4).

The VGT-110M* circuit breaker consists of three poles (columns) mounted on a common frame and mechanically connected to each other. All three poles of the switch are controlled by one spring drive of the PPrK type.

In the VGT-220I* switch, each pole has a frame and is controlled by its own drive.

The principle of operation of the switches is based on extinguishing the electric arc by a flow of SF6 gas (gas mixture), which is created due to the pressure drop provided by self-generation, i.e. due to the thermal energy of the arc itself. Switching on of the switches is carried out due to the energy of the closing springs of the drive, and switching off is carried out due to the energy of the spring of the disconnecting device of the switch.

The pole of the VGT-110 circuit breaker is a column filled with SF6 gas (gas mixture) and consisting of a support insulator, an arc extinguishing device with current leads, and a control mechanism with an insulating rod.

The pole of the VGT-220I* circuit breaker consists of two columns, the arc extinguishing devices of which are installed on double support insulators and are connected in series by two busbars. To distribute voltage evenly across the arc extinguishing devices, shunt capacitors are connected to them in parallel.

The arc extinguishing device contains openable main arc extinguishing contacts equipped with arc-resistant tips, a piston device for creating pressure in its internal cavity, and fluoroplastic nozzles in which gas flows acquire the direction necessary for effective extinguishing of the arc.

A spring drive of the PPrK type with a motor plant of working (cylindrical screw) springs is a separate unit placed in a sealed three-door cabinet. The drive has two shutdown electromagnets and is equipped with interlocking devices to prevent:

· command transmission to the switching electromagnet:

When the switch is on,

With the springs not charged,

When the position of the spring charging fist prevents the switch from turning on;

· passing a command to the tripping electromagnets when the circuit breaker is open;

· “idle” (with the switch on) dynamic discharge of the working springs;

· turning on the electric motor for winding springs when winding them manually.

The drive is equipped with signaling circuits:

· “The automatic power supply switch to the electric motor is not turned on,”

· “Malfunction in the spring winding system”,

· “The automatic control of the spring winding electric motor is not turned on,”

"Springs are not charged"

· “Dangerous decrease in temperature in the cabinet.”

The drive allows you to slowly operate the contacts of the switch when setting it up without any additional (for example, jacking) devices. The drive is easy to maintain and reliable in operation.

The circuit breaker frame and drive cabinet have an anti-corrosion coating.

The overall installation and connection dimensions of the VGT-110II circuit breaker are given in Figure 3.2.

SF6 circuit breakers for voltage 110 kV VEB series. OJSC "Uralelektrotyazhmash" has been producing SF6 tank switches of the VEB-1101G-40/2500 UHL1* type since 2001. The switch has a spring drive of the PPrK type and built-in current transformers.

The switch is intended for operation in open and closed switchgears in alternating current networks with a frequency of 50 Hz and a rated voltage of 110 kV in areas with a moderate and cold climate (up to minus 55°C) under the following conditions:

· environment - non-explosive, not containing aggressive gases and vapors in concentrations that destroy metals and insulation. Content of corrosive agents according to GOST 15150 (for type II atmosphere);

· the upper operating value of the air temperature surrounding the switch is 40°C;

· the lower operating value of the air temperature surrounding the switch is minus 55°C;

· in case of ice with an ice crust thickness of up to 20 mm and wind speed of up to 15 m/s, and in the absence of ice - with wind speed of up to 40 m/s;

· installation height above sea level - no more than 1000 m;

· tension of wires in the horizontal direction - no more than 1000 N.

When ordering, it is possible to supply it in climatic version T1 (upper operating value of ambient air temperature plus 55°C).

The switches have successfully passed a full range of tests for compliance with the requirements of Russian standards. The technical conditions have been agreed upon with RAO UES of Russia, the Ministry of Railways of the Russian Federation and Rosenergoatom. They have certificates of conformity: No. ROSS RU.MB03.B00090 and No. ROSS RU.MB03.H00089.

The switch is equipped with devices for electric heating of the poles, which, when the ambient temperature drops to minus 25°C, are automatically turned on and off at a temperature of minus 19-22°C.

Monitoring of SF6 gas leakage from the switch poles is carried out using electrical contact density detectors. The switch poles are equipped with an emergency burst disc.

The switch is delivered to the customer fully assembled, which ensures that the factory settings are retained and extremely simplifies installation and commissioning. Transportation to the installation site is possible both by rail and by road (truck).

Supervised installation and supervision of commissioning are carried out by specialists from the manufacturer.

Overall, installation and connection dimensions are given in Figure 3.3.

Main features and advantages of the switch:

· presence of built-in current transformers (with high accuracy classes);

· equipped with a modernized spring drive type PPrK-2000SM, the electrical circuit of which is made on an imported element base: with spring terminal clamps for connecting external circuits; with an increased number of signal contacts (12 NO, 12 NC and 2 pulse contacts), continuously passing currents over a wider range (from 5 to 25 A); with the ability to change the “setpoints” of the temperature, automatically turn on the heating and alarm about a “dangerous” decrease in temperature in the cabinet; with a modified, more user-friendly control panel design;

· design of an arc extinguishing device operating on the basis of autogeneration, unified with SF6 column switches and the VGT series;

· use of pure SF6 gas;

· use of double seals in connections, as well as a “liquid seal” in the sealing unit of the moving shaft. The natural level of leaks - no more than 0.5% per year - is confirmed by testing each switch at the manufacturer according to the methodology used in space technology;

· modern technological and design solutions and the use of reliable components, including high-strength insulators from foreign companies;

· high corrosion resistance of coatings (hot-dip galvanizing) used for steel structures of the circuit breaker;

· operation in both temperate and cold climates (down to minus 55°C);

· automatic switching on and off of electric heating of SF6 gas in tanks;

· high mechanical resource;

· small overall dimensions of the switch and weight;

· high switching resource specified for each pole, exceeding by 2-3 times the switching resource of the best foreign analogues (per each pole) in combination with a high mechanical resource, increased service life of seals and components provide, under normal operating conditions, no less than a 25-year service life before the first repair;

· the ability to disconnect load currents in the event of loss of excess gas pressure in the switch;

· minimal maintenance during the period between repairs;

· high fire and explosion safety;

· low noise level when activated (meets high environmental requirements);

· delivery of the circuit breaker fully assembled;

· full factory readiness, quick installation and commissioning (under the guidance of the chief staff of the manufacturing plant).

The main technical data of VEB series switches are given in Table 3.3.

Table 3.3. Main technical characteristics of VEB series switches

SF6 gas circuit breakers for voltage 220 kV VGK series. The SF6 switch VGK-2201G-31.5/3150 U1 is designed for switching electrical circuits and shunt reactors during operating and emergency modes in three-phase alternating current networks with a grounded neutral for a rated voltage of 220 kV.

The switch has an autonomous spring-hydraulic drive type PPGV-4 A2T-UHL1 double-acting TU 3414-014-48316876-2002. The technical specifications for the switch TU 16-2003 2BP.029.005TU are agreed upon with RAO UES of Russia. The switch complies with GOST 687 and has a certificate of conformity No. ROSS Ru.Me27.B00544.

The values ​​of climatic factors of the external environment are in accordance with GOST 15150 and GOST 15543.1 for climatic version U, in this case: installation altitude above sea level up to 1000 m; the operating value of the ambient air temperature is from minus 45°C to plus 40°C.

The circuit breaker is suitable for operation under the following conditions:

· the thickness of the ice crust during icy conditions is no more than 20 mm;

· wind speed in the presence of ice - no more than 15 m/s;

· wind speed in the absence of ice - no more than 40 m/s;

· permissible tension of wires in the horizontal plane applied to the terminals of the switch pole is no more than 1500 N.

The environment is non-explosive. The content of corrosive agents is in accordance with GOST 15150 (for type II atmosphere).

The main technical data of the VGK series circuit breakers are given in Table 3.4.

Table 3.4. Main technical characteristics of VGK series circuit breakers

Service life before average repair is at least 15 years. Service life of at least 30 years.

The warranty period from the date of commissioning of the circuit breaker is 5 years with operating hours not exceeding the resource values ​​for mechanical or switching resistance.

The switch is a set of 3 mechanically disconnected poles and a distribution cabinet.

Each pole consists of a column and a base with a drive. The column includes an arc extinguishing device and a support insulator. The column is installed on a plinth with a spring-hydraulic drive. The drive turns the switch on and off. The connection between the drive and the contacts of the arc extinguishing device is carried out through a tubular insulating rod passing inside the support insulator. Each pole is equipped with a SF6 gas density indicator to indicate when the SF6 gas pressure is decreasing.

The distribution cabinet contains elements of the electrical part of the circuit breaker control circuit and the hydraulic pump drive unit. The hydraulically driven base and distribution cabinet are equipped with main and anti-condensation heating and an automatic control system for the main heating.

An autonomous spring-hydraulic drive ensures the operation of the switch poles in simple “O and B” operations and in complex cycles. The springs are wound automatically by a hydraulic pump unit (HPU), powered by a three-phase 380 V network. The drive has an automatic control system for the hydraulic pump unit for pumping oil into the high-pressure system, which allows you to constantly maintain the level of stored energy. The drive has counters for the number of “on-off” operations.

The overall dimensions of the VGK series circuit breaker are shown in Figure 3.4.

Disconnectors for voltage 110 kV type RPD, RPDO. OJSC "Uralelektrotyazhmash" produces three-pole outdoor disconnectors of the RPD-110UHL1 (T1) series and single-pole disconnectors of the RPDO-110UHL1 (T1) series for a voltage of 110 kV, rated currents of 1,600 and 2,500 A; single-pole grounding switches for outdoor installation type ZRO-11 0 UHL1 (T1) for voltage 110 kV, rated current 1000 A, thermal current 40 kA. Disconnectors and grounding switches are controlled by motor and manual drives.

The main technical data of the disconnectors are given in Table 3.5.

Table 3.5. Main technical characteristics of disconnectors RPD and RPDO

In the designs of RPD, RPDO, units unified for this family of products are used (drives, contact groups, mechanical connection elements, insulators, etc.), therefore, as an example, a description of the design of the three-pole disconnector RPD-110 is given: a device that has a complete set all structural elements.

The disconnector consists of three-pole groups of disconnector and grounding switches (see Fig. 3.5.). Each group is controlled by its own drive.

The disconnector pole consists of two rotary columns of insulators mounted on a frame and carrying a current-carrying system with two pass-through contacts and one contact that opens in the horizontal plane. High-strength porcelain insulators, purchased only from import, are installed on swivel bases rotating on rolling bearings. The internal structure of the rotating bases is protected from the influence of the atmosphere.

The opening contact of the disconnector is made in the form of a cam contact attached to the end of one current conductor, and contact fingers attached to the end of the other. In the switched-on position of the disconnector, the contact fingers cover the cam contact. The pins and cam contacts are silver plated.

The feed-through contacts are made in the form of lamellas located around two coaxial copper rods. The lamellas and copper rods are silver coated and protected from the effects of the atmosphere. To increase the reliability of this connection, flexible connections are installed parallel to the feed-through contact.

The disconnector conductors are made of welded aluminum parts, which ensures their stable electrical resistance.

The disconnector can be equipped with one or two grounding switches, the knives of which move in a vertical plane. In the “O” position of the grounding switch, the blades are located horizontally along the pole frames.

Moving upward, the grounding switch knives close the contacts located on the current conductors of the disconnector.

The disconnector is equipped with a mechanical interlock that prevents the switching on of the grounding switches when the disconnector is switched on and the switching on of the disconnector when the grounding switches are switched on.

The three-pole disconnector and each of the grounding switches are controlled by separate motor or manual drives, and the motor drive is equipped with a manual control device. Both drives are equipped with electromagnetic interlock to prevent incorrect operations.

The drives have permanently switched on anti-condensation heating. The motor drive has an additional heating power of 0.4 kW, which is turned on and off automatically. It is possible to complete the products with motor drives with DC motors.

To ensure personnel safety when operating from manual control, the disconnector drive is installed on the outermost support, and the movable contacts of the disconnector, when disconnected, are directed away from the drive, into the inside of the disconnector.

Main features and benefits:

· High-strength porcelain rod insulators, purchased only for import.

· Welded aluminum current conductors with a minimum number of contact connections provide long-term stable electrical resistance.

· Opening contacts without additional springs and hinges.

· Durable rotary bases on rolling bearings withstand large bending loads and ensure stability of mechanical characteristics.

· Imported self-lubricating hinges that do not require maintenance throughout their entire service life.

· The fixed position of the driving drive levers with the transition beyond the “dead” point eliminates the possibility of involuntary switching under the influence of external factors.

· Maximum factory readiness for easy and quick installation. The disconnector is supplied adjusted and can be equipped with factory supports (stands).

· Additional safety - the disconnector drive is located on the outer support, outside, and the disconnector contacts move in the direction of the drive when disconnected.

· Frames and supports (brackets) of the disconnector are coated with hot zinc.

· Minimal maintenance during operation.

· Service life - 40 years, warranty period - 5 years.

JSC "Research and Design Institute of High-Voltage Equipment Engineering" St. Petersburg. JSC "NIIVA" - has a 125-year history, first as part of the plant and association "Electroapparat", and then since 1952 - as an independent organization; since 1993 - Open joint-stock company "Scientific Research Institute of High-Voltage Apparatus Engineering" (JSC "NIIVA").

High-voltage switching and measuring equipment, developed at the institute over the years, is produced by many factories in Russia and foreign countries; almost all the energy sector of Russia, the CIS countries and many countries of the world is equipped with it.

World-renowned electrical engineering scientists worked within the walls of the institute over the years; the theoretical foundations of high-voltage apparatus construction were practically laid here.

In recent years, the institute has developed single-break tank SF6 switches for 110-750 kV, column switches for voltage 110 kV, instrument SF6 transformers for 110-220 kV, produced by JSC Energomechanicheskiy Zavod, JSC VO Elektroapparat, St. Petersburg ; plant “Electrokhimpribor”, Yekaterinburg. And also together with the company “Hyundai Heavy Industries Co., LTD”, Republic of Korea - GIS 362 and 800 kV with breaking currents of 63 and 50 kA and rated current 8000 A, GIS 500 kV with breaking current 50 kA and rated current 3150 A.

Various gas mixtures are often used to extinguish an electric arc. 110 kV and 220 kV SF6 circuit breakers operate precisely on this principle and can be used for operation in emergency situations.

Design and types

Gas-insulated high-voltage circuit breakers are operational control devices for monitoring high-voltage power supply lines. These devices have a very similar design to oil ones, but at the same time, they use not an oil mixture, but a gas compound to extinguish the arc. Often this is sulfur. Oil switches require special care: according to regulations, periodic oil changes and cleaning of working contacts are required. SF6 ones do not need this. The main advantage of SF6 gas is its durability: it does not age and minimally pollutes the mechanical parts of the device.

Photo - high voltage equipment

They are:

1. Core (HPL 245B1, MF 24 Schneider Electric);
2. Tank (ABB 242PMR, DT2-550 F3 - Areva manufacturer).

The SF6 column circuit breaker is a standard disconnecting device that operates on one phase only (for example, LF 10 from Schneider Electric). It is used for 220 kV network. Structurally they consist of two systems: contact and arc extinguishing. Both of them are located in a container filled with SF6 gas. They can be either manual (control is performed exclusively mechanically) or remote. Due to this separation, they have quite large overall dimensions.

Photo - design drawing

The tanks have smaller dimensions and are complemented by the PPRM 2 drive for the SF6 circuit breaker. The drive is distributed over several phases, which allows for soft voltage regulation (switching on and off). Their advantage is also that they can carry heavy loads thanks to the current transformer built into the system.

In addition to design features, gas-insulated switches are classified according to the principle of arc extinguishing:

1. Auto-compression or air;
2. Rotating;
3. Longitudinal blast;
4. Longitudinal blast with additional heating of SF6 gas.

Operating principle and purpose

High voltage SF6 circuit breakers operate by isolating the phases from each other using SF6 gas. When a signal is triggered that the electrical equipment needs to be turned off, the contacts of individual cameras (if the device is a speaker device) open. Thus, the built-in contacts form an arc, which is placed in a gaseous environment. It decomposes the gas into individual components, but at the same time it itself decreases due to the high pressure in the container. If the system is installed at low pressure, then additional compressors are used to increase pressure and create a gas blast. To equalize the current, shunting is additionally used. Visually, the work flow looks like this:

Photo - work diagram

Separately, it is necessary to say about tank-type models. Their control is carried out by drives and transformers. The drive mechanism for this installation is a regulator: it is necessary to turn on and off electrical energy and hold the arc (if necessary) at a certain level. Drives are:

1. Spring;
2. Spring-hydraulic.

The spring type has a very simple principle of operation and a high level of reliability. In it, all work is performed only by mechanical parts. The spring is clamped and fixed at a certain level, and when the position of the control lever changes, it is released. Based on its operating principle, a scientific presentation of the action of sulfur hexafluoride in an electrical environment is often prepared.

Photo - VGU-35

Modern spring-hydraulic drives, in addition to the spring, are additionally equipped with a hydraulic control system. They are considered more effective, because spring mechanisms can themselves change the position of the latch.

Advantages of SF6 circuit breakers:

1. Versatility. These switches are used to control networks with any voltage;
2. Speed ​​of action. The reactions of SF6 gas to the presence of an electric arc occur in a fraction of a second, this allows for quick emergency shutdown of the controlled system;
3. Suitable for use in conditions of fire hazard and vibration;
4. Durability. Contacts in contact with SF6 gas practically do not wear out, gas mixtures do not need to be replaced, and the outer shell has high protection rates;
5. Suitable for disconnecting high voltage alternating and direct current, while their analogues, vacuum models, cannot be used on high-voltage networks.

But such devices have certain flaws:

1. High price due to the complexity of production and the high cost of the SF6 gas mixture;
2. Installation is carried out only on a foundation or a special electrical panel, and this requires special instructions and experience;
3. Switches do not work in low temperatures;
4. When necessary maintenance, special equipment must be used.

Photo - industrial gas-insulated load switch

Video: features of SF6 switches

Specifications

Let's consider the technical characteristics of switches from different manufacturers and types of operation.

MEK SF6 gas spring circuit breaker HD4 (factory ABB factory):

VGBEP-35 (VGB-35, VGBE):

VGT-35 (VMT-35):

Core VGT-110:

VGU-110 (gas power):

Column switch GL314 Alstom:

Generator power switching devices with spring drive – FKG 2:

SF6 gas compression circuit breaker from Siemens (Siemens) 3AP1FG-245 (foundations required for installation):

You can buy suitable SF6 switches at any electrical store. Their cost depends on the type of device and its manufacturer. The price list in Samara, Moscow, Yekaterinburg and other cities varies from 100 dollars to several thousand.

1. Brief characteristics of SF6 column switches 1

1.1.Introduction 1

1.2. Purpose of SF6 column switches 2

1.3. Requirements for compliance with factory instructions for the operation and repair of SF6 column switches 3

1.4. Risks arising during the operation of SF6 column switches 4

1.6.List of types of gas-insulated core switches operated at network enterprises of the Russian Federation. 5

2. Design of SF6 column switches 5

2.1.Technical characteristics of SF6 column switches 5

2.2.Description of the design of SF6 column circuit breakers: arc extinguishing device, support insulator, drive, control cabinet, safety valve, instruments and devices that control the state of SF6 gas, parameter monitoring 10

2.2.1.Description of SF6 column switches type HPL-245B1 10

2.2.2.Description of column SF6 circuit breakers type LTB-145D1/B 13

2.2.3.Description of column SF6 circuit breakers type 3AP1FG – 145/EK 17

2.2.4. Description of column SF6 gas switches type VGT-110 18

3. External view of the installation of a set of SF6 column switches 22

4. Requirements for occupational safety, explosion and fire safety of SF6 column switches 23

1. Brief characteristics of SF6 column switches

   1. Introduction

Switches are designed for operational and emergency switching in power systems, i.e. performing operations on and off individual circuits with manual or automatic control. When switched on, the switches must pass load currents without hindrance. The nature of the operating mode of these devices is somewhat unusual: the normal state for them is both the on state, when they flow around the load current, and the off state, in which they provide the necessary electrical insulation between open circuit sections. The switching of the circuit, carried out when switching the switch from one position to another, is carried out irregularly, from time to time, and it is extremely rare for it to comply with the specific requirements for disconnecting a short circuit that occurs in the circuit. Switches must reliably perform their functions during their service life (30-40 years), being in any of the specified states, and at the same time always be ready to instantly effectively perform any switching operations, often after a long stay in a stationary state. It follows that they must have a very high availability factor: with a short duration of switching processes (several minutes per year), constant readiness for switching must be ensured.

The functioning of high-voltage electrical networks in terms of current characteristics is not comparable with the operation of household analogues. Accordingly, in the event of an emergency, more powerful devices than standard automatic devices are needed to turn off the equipment and extinguish the electric arc.

SF6 circuit breakers (EGS) are used as protective structures, which can be controlled both manually and automatically. We have described in detail the design features and operating principle of the devices. Provided recommendations for installation, connection and maintenance.

SF6 gas is sulfur hexafluoride, which is classified as an electrical gas. Due to its insulating properties, it is actively used in the production of electrical devices.

In its neutral state, SF6 gas is a non-flammable, colorless and odorless gas. If we compare it with air, we can note its high density (6.7) and molecular weight, which is 5 times higher than air.

One of the advantages of SF6 gas is its resistance to external manifestations. It does not change characteristics under any conditions. If disintegration occurs during an electric discharge, then a full restoration necessary for operation soon occurs.

The secret is that SF6 molecules bind electrons and form negative ions. The quality of “electronegation” endowed 6-sulfur fluoride with such a characteristic as electrical strength.

In practice, the electrical strength of air is 2-3 times weaker than the same property of SF6 gas. Among other things, it is fireproof, as it is a non-flammable substance, and has cooling properties.

When the need arose to find a gas to extinguish the electric arc, they began to study the properties of SF6 (sulfur hexafluoride), carbon 4-chloride and freon. SF6 won the tests

The listed characteristics made SF6 gas most suitable for use in the electrical field, in particular in the following devices:

• power transformers operating on the principle of magnetic induction;
• complete type switchgears;
• high voltage lines connecting remote installations;
• high voltage switches.

But some properties of SF6 gas led to the need to improve the design of the switch. The main disadvantage concerns the transition of the gaseous phase to the liquid phase, and this is possible under certain ratios of pressure and temperature parameters.

In order for the equipment to operate without interruption, it is necessary to provide comfortable conditions. Let’s assume that for the operation of SF6 devices at -40º, a pressure of no more than 0.4 MPa and a density of less than 0.03 g/cm³ are required. In practice, if necessary, the gas is heated, which prevents the transition to the liquid phase.

SF6 circuit breaker design

If we compare SF6 devices with analogues of other types, then in design they are closest to oil devices. The difference lies in the filling of the chambers to extinguish the arc.

In order to extinguish an electric arc, many different gas mixtures are often used. Equipment filled with SF6 gas works on this principle and is used for work in emergency situations. In this article we will look at the design, principle of operation and purpose of SF6 switches.

What does the equipment consist of and what types of designs are there?

A gas-insulated high-voltage circuit breaker is a device whose purpose is to control and monitor a high-voltage power supply line. The design of such equipment resembles the mechanism of an oil device, only a gas compound is used for extinguishing instead of an oil mixture. Typically, sulfur is used. Unlike an oil appliance, a SF6 appliance does not require special care. Its main advantage is durability.

SF6 circuit breakers are divided into:

1. Kolonkovy. The use of such a structure is optimal only for a 220 kV network. This disconnecting device operates on one phase. The design includes two systems, which are placed in a container with SF6 gas. This is a contact and arc extinguishing system. They can also be either manual or remote. This is considered the main reason for their large size.
2. Tank. The dimensions are smaller than core ones. The design has an additional drive, which has several phases. Thanks to this, you can smoothly and gently regulate the switching on and off of the voltage. And due to the fact that a current transformer is built into the system, the mechanism is capable of carrying heavy loads.

According to the method of extinguishing the electric arc, SF6 power circuit breakers are divided into:

• air, also called auto-compression;
• rotating;
• longitudinal blast.

Operating principle and scope

How does a high voltage SF6 circuit breaker work? Due to the isolation of the phases from each other through SF6 gas. The principle of operation of the mechanism is as follows: when a signal is received to turn off electrical equipment, the contacts of each camera open. Built-in contacts create an electric arc, which is placed in a gaseous environment.

This medium separates the gas into individual particles and components, and due to the high pressure in the tank, the medium itself is reduced. Possible use of additional compressors if the system operates at low pressure. Then the compressors increase the pressure and create a gas blast. Shunting is also used, the use of which is necessary to equalize the current.

The designation in the diagram below indicates the location of each element in the switch mechanism:

As for tank-type models, control is carried out using drives and transformers. What is the drive for? Its mechanism is a regulator and its purpose is to turn the electricity on or off and, if necessary, to hold the arc at a set level.

Drives are divided into spring and spring-hydraulic. Spring ones have a high degree of reliability and have a simple operating principle: all the work is done thanks to mechanical parts. The spring is capable of compressing and decompressing under the action of a special lever, as well as being fixed at a set level.

Spring-hydraulic drives of switches additionally have a hydraulic control system in their design. Such a drive is considered more efficient and reliable, because the spring device can itself change the level of the latch.

Advantages and disadvantages of equipment

As with any designs and mechanisms, SF6 circuit breakers have their own advantages and disadvantages. The advantages of the device include:

1. Multifunctionality. The purpose and use of such a mechanism is possible for any voltage in the network.
2. Speed ​​of action. SF6 reacts to the presence of an electric arc in a matter of seconds. Thanks to this, in the event of an emergency, it is possible to quickly turn off the controlled system.
3. Possible use in vibration and fire conditions.
4. Longevity. There is no need to replace gas mixtures. The contacts that come into contact with the mixtures are almost not subject to wear, and the outer casing has high protection rates.
5. Can be used on high voltage networks. Their analogues, such as vacuum devices, are not capable of doing this.

But these switches also have their drawbacks. For example:

1. Since the production of devices is very complex and SF6 gas mixtures are expensive, the price of the design itself is high.
2. The device does not operate at low temperatures.
3. When maintenance is required, specific equipment must be used.
4. The device must be installed on a special platform or foundation, and for this you must have experience and special instructions.

So we looked at the design, purpose and principle of operation of SF6 switches. We hope the information provided was useful and interesting for you!

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