Vacuum circuit breaker 110 kV outdoor installation

SF6 circuit breakers 110, 220 kV

Manufacturers of modern electrical equipment

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, incl. financial results from transactions with foreign currency.

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

‣‣‣ generated by transactions of recalculation of the value of assets and liabilities expressed in foreign currency, subject to payment in foreign currency;

‣‣‣ resulting from transactions of recalculation of the value of assets and liabilities expressed in foreign currency, payable in rubles;

‣‣‣ credited to accounts accounting͵ different from the account of the financial results of the organization. At the same time, 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.

PJSC (until 2015 OJSC) ʼʼUralelektrotyazhmashʼʼ. The plant, commissioned in 1934, today is PJSC (until 2015 OJSC) Uralelectrotyazhmash (PJSC (until 2015 OJSC) UETM) - the largest enterprise in Russia for the production of electrical equipment for generation, transmission, distribution and energy consumption. 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-voltage equipment;

· electric cars;

· turbogenerators;

· transformers;

· conversion technology.

Highly qualified and experienced personnel, wide production and technological capabilities provide PJSC (until 2015 OJSC) 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, PJSC (until 2015 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.

The constantly updated and improved production 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 for 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 circuit breaker 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. Basic specifications 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 commissioning of the switch is 2 years with operating hours not exceeding the service life 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.

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

The independent 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 operations “on - off”.

dimensions The poles of SF6 gas circuit breakers of the 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. Οʜᴎ are intended for use in open and closed switchgears in areas with moderate 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 temperature of the air surrounding the switch is 40°C;

· the lower operating value of the air temperature surrounding the circuit breaker is: for version U1 - minus 45°C when filling the circuit breaker with SF6 gas, for version HL 1 * - minus 55°C when filling the circuit breaker 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 speeds of up to 15 m/s, and in the absence of ice - with wind speeds 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 kgf).

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, and 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 drive operation and increases reliability;

· 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, incl. 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 life specified for each pole (clause 3.3), which is 2-3 times greater than the switching life of the best foreign analogues (per each pole), combined with a high mechanical life, increased service life of seals and components, provide under normal operating conditions, no less than 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 the VGT series circuit breakers are given in Table 3.2.

Table 3.2. Main technical characteristics of switches of the VGT series

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

· for currents in the range of over 60 to 100% of the rated shutdown current - 20 operations (thus, for a three-pole switch, 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 “switching on - arbitrary pause - switching off”.

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 KHL1* - 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 type PPrK.

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, ᴛ.ᴇ. due to the thermal energy of the arc itself. The switches are turned on due to the energy of the closing springs of the drive, and turned off - due to the energy of the spring of the switch's tripping device.

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 a direction that is extremely important 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:

– with the switch 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 circuit breaker supplying power 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,”

· “The springs are not charged”,

· “Dangerous decrease in temperature in the cabinet”.

The drive allows you to slowly operate the switch contacts 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.

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. PJSC (until 2015 OJSC) Uralelectrotyazhmash has been producing SF6 tank circuit breakers 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 moderate and cold climates (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 temperature of the air surrounding the switch is 40°C;

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

· in case of ice with an ice crust thickness of up to 20 mm and wind speeds of up to 15 m/s, and in the absence of ice - with wind speeds 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, automatically turn 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 circuit breaker 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), continuously passing currents of a wider range (from 5 to 25 A); with the ability to change the “setpoints” of the temperature for automatically turning on the heating and alarming about a “dangerous” decrease in temperature in the cabinet; with a modified, more user-friendly control panel design;

· design of the arc extinguishing device, unified with gas-insulated column circuit breakers and the VGT series, operating on the basis of self-generation;

· use of pure SF6 gas;

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

· possibility of disconnecting load currents in case of loss of excess gas pressure in the switch;

· minimal maintenance 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 manufacturer’s supervisory staff).

The main technical data of VEB series circuit breakers 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 circuit breaker TU 16-2003 2BP.029.005TU have been 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; operating ambient temperature ranges from minus 45°C to plus 40°C.

The switch is suitable for operation with 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 switches

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 service life 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.
Posted on ref.rf
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 circuit breaker 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 operations “on - off”.

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

Disconnectors for voltage 110 kV type RPD, RPDO. PJSC (until 2015 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

Parameter name	RPD-110	RPDO-110
Rated voltage, kV
Highest operating voltage, kV
Rated current, A, not less	1600; 2500
Thermal resistance current (It), kA
The largest peak of through current (electrodynamic resistance current) (Id), kA
Thermal current flow time (for disconnector/grounding switch), s	3/1
Values of no-load currents of transformers, charging currents of overhead and cable lines that can be switched off and on with a disconnector, with a distance between poles: - 1800 mm mm - 2000 mm mm
Mechanical life (N) for main circuits and grounding circuits

In the designs of RPD, RPDO, units standardized for this family of products are used (drives, contact groups, mechanical connection elements, insulators, etc.), in this regard, as an example, a description of the design of the three-pole disconnector RPD-110 is given: a device with a full set of all 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 rotating 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 imports, are installed on swivel bases rotating on rolling bearings. The internal structure of the rotating bases is protected from atmospheric influences.

The open 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 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 elements. 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 blades 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 switch is 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 locking to prevent incorrect operation.

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 can withstand large bending loads and ensure stable mechanical characteristics.

· Imported self-lubricating joints that do not require maintenance during their entire service life.

· The fixed position of the driving levers of the drive 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 must 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 away from the drive when disconnected.

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

· Minimal maintenance during operation.

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

PJSC (until 2015 OJSC) "Research and Design Institute of High-Voltage Apparatus Engineering" ᴦ. Saint Petersburg. PJSC (until 2015 OJSC) "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 "Research Institute of High-Voltage Equipment Engineering" (PJSC (until 2015 OJSC) "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, measuring SF6 gas transformers for 110-220 kV, produced by PJSC (until 2015 OJSC) “Energomechanicheskiy Zavod”, PJSC (until 2015 JSC) VO “Electroapparat”, ᴦ. St. Petersburg; plant “Electrokhimpribor”, ᴦ. 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.

110, 220 kV SF6 circuit breakers - concept and types. Classification and features of the category "SF6 circuit breakers 110, 220 kV" 2017, 2018.

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:

Core (HPL 245B1, MF 24 Schneider Electric);
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:

Auto-compression or air;
Rotating;
Longitudinal blast;
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:

Spring;
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:

Versatility. These switches are used to control networks with any voltage;
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;
Suitable for use in conditions of fire hazard and vibration;
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;
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:

High price due to the complexity of production and the high cost of the SF6 gas mixture;
Installation is carried out only on a foundation or a special electrical panel, and this requires special instructions and experience;
Switches do not work in low temperatures;
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.

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

Photo – high voltage equipment

They are:

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

Photo – design drawing

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

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

Operating principle and purpose

Photo - work diagram

Spring;
Spring-hydraulic.

Photo – VGU-35

Advantages of SF6 circuit breakers:

Versatility. These switches are used to control networks with any voltage;
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;
Suitable for use in conditions of fire hazard and vibration;
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;
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:

High price due to the complexity of production and the high cost of the SF6 gas mixture;
Installation is carried out only on a foundation or a special electrical panel, and this requires special instructions and experience;
Switches do not work in low temperatures;
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):

Air circuit breakers

In air circuit breakers, the arc is extinguished by blowing compressed air (at a pressure of 2-4 MPa and above) coming from a reservoir, most often integral with the base.

Remote controls of air switches are made with one or more phase breaks and with longitudinal or transverse air blast.

A single-break arcing device can be used to interrupt significant current at only a relatively small voltage. Switches with voltages of 220 kV and higher must have several breaks connected in series. For example, at an air pressure of 4 MPa and a voltage of 110 kV, a switch with one break is capable of disconnecting a current of about 40 kA. A 220 kV circuit breaker must have two breaks, and a 500 kV circuit breaker must have four breaks.

Air circuit breakers with rated voltages from 110 to 1150 kV are designed in series and assembled from standardized parts, the most important of which is an arc extinguishing module with two breaks, designed for a certain nominal voltage of the order of 110-250 kV depending on air pressure. The number of modules connected in series is selected in accordance with the rated voltage.

A necessary condition for the satisfactory operation of multiple-break circuit breakers is the uniform distribution of the restoring voltage between the breaks. To ensure uniform voltage distribution between breaks at any frequency of the recovery voltage, it is advisable to use capacitive voltage dividers (Fig. 1.a). These switches are usually also equipped with shunt resistors connected in parallel with each break (Fig. 1.b). In this case, small damping devices (marked 1,2,3,4) are needed at each break to turn off the accompanying current.

Rice. 1.

Air circuit breaker series

The design of air circuit breakers used in substations is mainly determined by the method of creating an insulating gap between the contacts of the circuit breaker in the open position, the method of supplying compressed air to the arc extinguishing devices, the circuit breaker control system, the presence of shunt resistors and voltage dividers and some other features. The following series of air circuit breakers are distinguished.

VVB series circuit breaker for rated voltages from 110 to 750 kV

The most advanced air circuit breakers are those in which the arc extinguishing chamber is located directly in the compressed air tank. Arc extinguishing modules with two breaks and one-way blowing have a nominal voltage of 110 kV. The number of modules for circuit breakers with rated voltages of 110, 220, 330, 500 and 750 kV is 1, 2, 4, 6 and 8, respectively. The modules are installed on columns made of porcelain insulators. 110 kV circuit breakers have one module and one support column. Switches 220-750 kV - two modules on each column, located one above the other and connected in series with a jumper. Figure 2 shows an air circuit breaker of type VVB-220B-31.5/2000U1 for a rated voltage of 220 kV, insulation type B, rated breaking current of 31.5 kV. rated current 2000 A, for installation in moderate climates outdoors.

Their total shutdown time is 0.06 - 0.08 s. depending on rated voltage. Operation has shown their high reliability.

Rice. 2. Switch series VVB-220 with two modules on one column: 1 - control cabinet; 2 -- support insulator; 3 -- arc extinguishing device; 4 - voltage divider; 5 - connecting conductor; 6 - shunt resistor.

The air pressure for 110, 220 and 500 kV circuit breakers is 2 MPa; for 750 kV circuit breakers - 2.6 MPa; 330 kV - 2 and 2.6 MPa.

VVB series switches have a pneumatic control system. Air ducts made of insulating material are laid in the hollow support columns, one of which is used to replenish the tanks with compressed air, and the second is used to control the contact and blow valves of the energized modules.

In Fig. 3.a shows a pole of a VVB series circuit breaker for a voltage of 110 kV. The compressed air tank 1 is located on the support insulator 2, and control air ducts pass through the same insulator. Control cabinet 3 is located at the base of the circuit breaker. The remote control is connected to the external circuit by the current-carrying parts of the bushings 4. Uniform distribution of voltage between the two breaks of the device is ensured with the help of capacitors 5. The device diagram is shown in Fig. 3.b, where 5 are shunt capacitors that ensure equal voltages at the two breaks of the device; 6 - main contacts; 7 - auxiliary; 8 - shunt resistors that serve to reduce the speed of voltage recovery. The current through the shunt resistors is switched off by contacts 7 after the arc is extinguished in the main breaks 6. From Fig. 3.b it is clear that the tank body 2 is energized.

Rice. 3.

In the considered design, only the steel tank is under high pressure. This allows you to increase the air pressure in the tank to 3.5 -4 MPa and increase the switch-off current.

High-voltage circuit breakers that use SF6 gas as an insulating and arc-extinguishing medium are becoming increasingly widespread, as they have high switching and mechanical resources, breaking capacity, compactness and reliability compared to air, oil and low-oil high-voltage circuit breakers.

Advances in the development of gas-insulated switchgear have directly had a significant impact on the implementation of compact outdoor switchgear, indoor switchgear and gas-insulated switchgear. SF6 circuit breakers use different arc extinguishing methods depending on the rated voltage, rated interrupting current and the characteristics of the power system (or individual electrical installation).

In SF6 arc extinguishing devices, in contrast to air arc extinguishing devices, when extinguishing the arc, the outflow of gas through the nozzle does not occur into the atmosphere, but into a closed chamber volume filled with SF6 gas at a relatively low excess pressure.

According to the method of extinguishing the electric arc during shutdown, the following SF6 gas circuit breakers are distinguished:

1. Auto-compression SF6 gas circuit breaker, where the required mass flow of SF6 gas through the nozzles of the compression arc extinguishing device is created along the movable system of the circuit breaker (auto-compression circuit breaker with one pressure stage).

2. SF6 gas circuit breaker with electromagnetic blast, in which the extinguishing of the arc in the arc extinguishing device is ensured by its rotation along the ring contacts under the influence of the magnetic field created by the switched current.

3. SF6 circuit breaker with high and low pressure chambers, in which the principle of providing gas blast through the nozzles in the arc extinguishing device is similar to air arc extinguishing devices (SF6 gas circuit breaker with two pressure levels).

4. Self-generating SF6 gas circuit breaker, where the required mass flow of SF6 gas through the nozzles of the arc extinguishing device is created by heating and increasing the pressure of SF6 gas by a shutdown arc in a special chamber (self-generating SF6 gas circuit breaker with one pressure stage).

Let's look at some typical designs of SF6 circuit breakers for 110 kV and above.

SF6 circuit breakers 110 kV and higher per break from various companies have the following nominal parameters: Unom = 110-330 kV, Inom = 1-8 kA, Io.nom = 25-63 kA, SF6 gas pressure pH = 0.45-0.7 MPa(abs), shutdown time is 2-3 periods of short-circuit current. Intensive research and testing of domestic and foreign companies made it possible to develop and put into operation a gas-insulated circuit breaker with one break at Unom = 330-550 kV at Io.nom = 40 - 50 kA and the current interruption time is one short-circuit current period.

A typical design of an auto-compression SF6 circuit breaker is shown in Fig. 1.

The device is in the off position and contacts 5 and 3 are open.

Rice. 1.

Current supply to fixed contact 3 is carried out through flange 2, and to movable contact 5 through flange 9. A chamber with an adsorbent is mounted in the top cover 1. The supporting insulating structure of the SF6 switch is mounted on the footrest 11. When the switch is turned on, a pneumatic actuator 13 is activated, the rod 12 of which is connected through an insulating rod 10 and a steel rod 8 with a movable contact 5. The latter is rigidly connected to a fluoroplastic nozzle 4 and a movable cylinder 6. The entire movable EV system (elements 12-10-8-6-5) moves upward relative to the stationary piston 7, and the cavity K of the arc extinguishing system of the circuit breaker increases.

When the switch is turned off, the rod 12 of the driving power mechanism pulls the moving system down and increased pressure is created in cavity K compared to the pressure in the switch chamber. This self-compression of SF6 gas ensures the outflow of the gas medium through the nozzle, intensive cooling of the electric arc that occurs between contacts 3 and 5 during shutdown. Position indicator 14 gives the initial position of the contact system of the switch. In a number of designs of auto-compression SF6 gas circuit breakers, spring, hydraulic power drive mechanisms are used, and the flow of SF6 gas through the nozzles in the arc-extinguishing chamber is carried out according to the principle of double-sided blasting.

In Fig. Figure 2 shows a tank-type SF6 switch of the VGBU type 220 kV (Inom=2500 A, Io.nom=40 kA NIIVA OJSC with an autonomous hydraulic drive 5 and built-in current transformers 2. The EV has three-phase control (one drive for three phases) and is equipped with porcelain (polymer) tires of 1 air-SF6 inputs.

In the gas-filled tank 3 there is an arc extinguishing device, which is connected to the hydraulic drive 5 through a transmission mechanism located in the gas-filled chamber 4. The design of the tank SF6 circuit breaker is mounted on a metal frame 6. To fill the circuit breaker with SF6 gas, connector 7 is used. When installing the circuit breaker in an outdoor switchgear, the gas pressure in the chambers is usually is equal to one atm (abs.) and then it is necessary to ensure p = pH.

Rice. 2.

The advantages of tank-type SF6 circuit breakers with built-in current transformers over sets of “column SF6 circuit breaker plus a free-standing current transformer” are: increased seismic resistance, smaller area of the alienated territory of the substation, less volume of required foundation work during the construction of substations, increased safety of substation personnel (arc extinguishing devices are located in grounded metal tanks), the possibility of using SF6 gas heating when used in areas with cold climates.

In the designs of tank circuit breakers 220 kV and above, for outdoor switchgear it is necessary to increase the nominal pressure of SF6 gas (pnom > 4.5 atm (abs.)), therefore, heating of the gas medium is introduced in order to prevent liquefaction of SF6 gas at low ambient temperatures or mixtures of SF6 gas with nitrogen are used or tetrafluoromethane.

As practice shows, for a rated voltage of 330–500 kV, tank switches with one break for rated currents of 40–63 kA are the most promising type of switching equipment for outdoor switchgear and switchgear.

Circuit breaker VGB-750-50/4000 U1 developed by OJSC NIIVA (Fig. 3) with a double-break auto-compression arc extinguishing device, built-in current transformers, polymer air-SF6 bushings, is equipped with two hydraulic drives per pole, which allows for a total shutdown time of no more duration of two periods of industrial frequency current.

In the on position of the SF6 circuit breaker, the resistors are bridged by the main contacts. When disconnecting, the resistor contacts open first, then the main ones, then the arcing contacts. When turned on, the resistor contacts close first, followed by the arc extinguishing and main contacts. To equalize the voltage distribution, each gap is shunted with capacitors.

Column SF6 circuit breakers with one break for a rated voltage of 110-220 kV with a rated breaking current of 40-50 kA have become widespread.

Rice. 5

A typical design of a column-type SF6 circuit breaker of the VGP type 110 kV (Inom = 2500 A, Io.nom = 40 kA) with a spring drive by Elektroapparat OJSC is shown in Fig. 5.