Device for distributing electrical energy with cable line test unit

Abstract

FIELD: electrical engineering.SUBSTANCE: invention relates to designs of electrical apparatus for use as part of an equipment complex for distributing electrical energy. The device for distributing electrical energy comprises a housing with a power equipment chamber, in which a power switch unit, a two-position switch-disconnector, busbars are located, and a cable chamber, wherein the vacuum chambers are located in the power switch unit, the busbars are electrically connected to the vacuum power switch via the two-position switch-disconnector, the cable chamber is configured to connect a load, the two-position disconnector-earthing switch is connected to the earthing circuit, and the device comprises a unit intended for testing the cable line, electrically connected to the cable line via the two-position disconnector-earthing switch and the power vacuum switch, configured to access the cable line for testing the cable line, containing a metal plate connected to the earthing circuit directly and via the two-position disconnector-earthing switch, and containing an arc protection device.EFFECT: increasing personnel safety during routine maintenance on cable lines.4 cl, 2 dwg

Description

[0001] The proposed invention relates to the field of electrical engineering, in particular to the designs of electrical apparatus intended for use as part of a complex of equipment for distributing electrical energy.

[0002] The prior art contains information on similar devices. Thus, a decision is known on the European Union patent for invention No. 2639903 "Switchgear" (IPC H02B 13 / 035; H02B 13 / 075; H02B 13 / 01; HITACHI LTD, Japan, application No. EP13155609 dated 02 / 18 / 2013, priority 03 / 14 / 2012, publication 09 / 18 / 2013). The power-receiving substation is equipped with a switchgear (SWG) containing a vacuum circuit breaker for disconnecting the load current or fault current, a disconnector and an earthing switch to ensure the safety of workers during maintenance and inspection of the load, detection devices for detecting voltage in the system and current in the system, a protective relay, etc. A switchgear assembly is proposed that includes an enclosure, a vacuum circuit breaker, a busbar, a cable, and a grounding device. The enclosure contains a circuit breaker chamber, a busbar chamber, a cable chamber, a grounding device drive chamber, and a control chamber, all separated by a grounded metal plate.The vacuum circuit breaker is located in the circuit breaker chamber. The busbar is located in the busbar chamber and is connected to the vacuum circuit breaker via a conductor. The cable is located in the cable chamber and is connected to the load at one end. The grounding device is actuated by the grounding device drive, located in the grounding device drive chamber, connected to the vacuum circuit breaker via a conductor, and connected to the other end of the cable. The busbar is a solid-insulated busbar. The wire connecting the vacuum circuit breaker to the busbar and the conductor connecting the vacuum circuit breaker to the grounding device are formed by a conductor with solid insulation. The circuit breaker chamber and the grounding device are sealed. Furthermore, since a cable head and solidly insulated busbars with a surface grounding layer are used, there is no exposed charging part, with the exception of the vacuum circuit breaker.The single-line earth fault allows testing to be carried out not only in the circuit breaker chamber but also in the vacuum circuit breaker chamber, and the vacuum circuit breaker is located on the front surface of the panel.

[0003] A disadvantage of the existing technical solution is the large cubicle dimensions. The device's configuration implies a significant depth. Since the cubicle is open to double-sided maintenance, cable connections are made from the rear, as is the assembly of busbars during installation. Consequently, installing the device with its rear panel flush against a wall or another device is impossible, as a maintenance corridor is required. Consequently, the cubicle size and maintenance method impose additional requirements on the size of the room in which they are to be installed.Furthermore, the circuit breaker and earthing switch-disconnector are designed as separate devices without a rigid connection. This, under certain circumstances—for example, when the circuit breaker truck is rolled in while the circuit breaker itself is closed, with the busbars energized and the cubicle grounded—may allow voltage to flow to the ground, resulting in a three-phase short circuit. The main drawback is that in this technical solution, as in most other cubicles of a similar voltage class, the circuit breaker is located on the busbar side, not the load side. This circumstance prevents fault localization when voltage is applied from the load side due to personnel error, including during routine maintenance on cable lines.

[0004] The technical essence is close to the technical solution under the patent of the Russian Federation for utility model No. 82946 "Prefabricated chamber for single-sided maintenance (KSO-207 "NOVATION")" (IPC H02B 1 / 36, CJSC "Group of companies" Tavrida Electric ", Russian Federation, application No. 2008144668 dated 11 / 12 / 2008, priority 11 / 12 / 2008, publication 05 / 10 / 2009). A prefabricated chamber for single-sided maintenance, containing a compartment of prefabricated busbars, a high-voltage compartment with a vacuum circuit breaker, busbar and line disconnectors, mechanical indicators of the position of the vacuum circuit breaker, busbar and line disconnectors, current transformers and voltage transformers, a connection compartment with a linear earthing switch, a mechanical indicator of the position of the linear grounding conductor, zero-sequence current transformer and auxiliary transformer, relay compartment with control, protection, signaling, measurement and metering devices for electricity,wherein the high-voltage compartment and the connection compartment are provided with interlocking elements, characterized in that the high-voltage and relay compartments are made on a single metal structure - a retractable monoblock capable of occupying an operating position in which the main circuits are closed, the monoblock is located and fixed in the chamber, a control position in which the main circuits are open, the monoblock is located and fixed in the chamber, and a repair position in which the main circuits are open, the monoblock is pulled out of the chamber and fixed, and access to the busbar and connection compartments is closed with protective insulating covers, the busbar and line disconnectors are designed with the possibility of synchronous control by a key acting on a single drive with a gearbox, the windows of the drives of the busbar and line disconnectors and the line earthing switch are equipped with shutters that permit and prohibit access of the control key to the drives in accordance with the logic of the cabinet interlocks, while in the position,preventing access, the curtains can be locked with a padlock.

[0005] The drawback of this technical solution is that the cubicle lacks a cable line testing unit. Therefore, access to the cable compartment is required for routine maintenance on the cable line. Due to the design of the device, cable connections can be made without adapters, by connecting cable lugs directly to the terminals. This requires disconnecting all three phases from the cubicle, grounding two of them, and reassembling them after completion. This is a labor-intensive operation and poses a high risk of improper or poor-quality reassembly. Given the cubicle's depth and the phases' arrangement in the cable compartment, one after another, deep within the cubicles, disconnecting them is complicated.Additionally, the conductors between phases and busbars are not insulated; in this case, the insulation is air, which means that such conductors cannot be used in harsh operating conditions, for example, in the presence of conductive dust, or in damp or wet rooms.

[0006] The closest in essence is the technical solution under the patent of the Russian Federation for invention No. 2217851 "Complete switchgear "ETALON"" (IPC H02B 7 / 00, CJSC "Group of companies" Tavrida Electric ", Russian Federation, application No. 2002106548, 03 / 14 / 2002, priority 03 / 14 / 2002, publication 11 / 27 / 2003). The invention relates to the field of electrical engineering, namely to the design of a complete switchgear of one-sided maintenance with vacuum circuit breakers. The device consists of a housing in which there is a monoblock combining a vacuum circuit breaker with vacuum chambers and a disconnector-earthing switch with movable contacts. This monoblock can be removed from the housing after grounding the cables without removing voltage from the busbars. The axes of the busbars, contacts of the vacuum chambers and contacts The earthing switches are not arranged in rows, but in triangles in three mutually perpendicular directions in space.The technical result of the invention is a reduction in the size of the complete switchgear and the ability to replace the circuit breaker without shutting down the substation. When the switchgear is closed, the cables are connected to the busbars via vacuum interrupter contacts and disconnector-earthing switch contacts. When disconnecting from the busbars is required, the vacuum circuit breaker is first opened (opening the vacuum interrupter contacts), and then, by turning a special drive handle, the lead screws rotate and move the moving contacts to the open position. Operation of the circuit breaker and disconnector-earthing switch is determined by interlocks in accordance with GOST and IEC standards. A mimic diagram on the front panel displays the contact positions of the vacuum circuit breaker and disconnector-earthing switch.When cable grounding is required, for repair or maintenance, the movable contacts of the disconnector-earthing switch are moved to the grounded position and the contacts of the vacuum circuit breaker are closed. This procedure is not critical even in the event of operator error (grounding a live cable), as the vacuum circuit breaker is designed to operate with short-circuit currents. After completing the grounding procedure, the cables are grounded through the busbars, closed vacuum interrupters, and the movable and fixed contacts of the disconnector-earthing switch. One of the fixed contacts is implemented in the drive grounding plate, connected to the substation grounding circuit. In this state of the complete switchgear, it is possible to remove the cable compartment cover (electromagnetic interlock) to apply portable grounding to the cable lugs, if necessary, after first testing with an indicator to ensure the absence of voltage.After this, the circuit breaker compartment cover can be removed, revealing the detachable threaded connections securing the vacuum circuit breaker base to the housing and the connections securing the fixed contacts of the vacuum interrupters to the busbars. The switchgear, according to the description, also allows for high-voltage testing of cable insulation by applying a test voltage to the terminals and high-voltage testing of the vacuum interrupters. The vacuum interrupters are open, and the contacts of the disconnector-earthing switch are in the grounded position. The cable terminals are disconnected, and a test voltage is applied to their connections.

[0007] The presented technical solution generally solves a problem similar to the stated one. However, access to the tested cable lines is achieved directly through the cable lugs with the low-voltage compartment cover removed. There is no cable line testing unit, which reduces the safety and ease of use of the device. Testing a three-wire cable requires disconnecting all cables and grounding two of the three phases. This is problematic in the cramped conditions of the cable compartment, increasing labor intensity and reducing the safety of personnel performing maintenance on the cable line. Furthermore, the power module of the described technical solution, which includes a vacuum circuit breaker, a three-position disconnector with position sensors, and interlocking devices, is designed as a single unit. Therefore, if any of the mechanisms or, for example, the vacuum chamber of one of the phases fails, the entire unit must be replaced.

[0008] Thus, the existing state of the art does not contain information on technical solutions that solve a number of technical problems. Thus, the main technical problem solved by the proposed invention is to improve personnel safety during routine maintenance on cable lines. This additionally results in a reduction in labor intensity, the elimination of the need for complex directional and step-by-step current protection in the event of voltage being supplied to the grounded cell from the load side, the possibility of localizing an accident and disconnecting the short-circuit point by the cell's own circuit breaker in the event of voltage being supplied to the grounded cell from the load side, the elimination of the need to disconnect the downstream substation from voltage, and a reduction in the short-circuit point disconnection time by the time of relay or arc protection operation, or by the response time of the operating personnel.reducing the time it takes for short-circuit currents to flow throughout the entire circuit from the second power source through the consumer to the point of the short circuit and, as a consequence, reducing the negative factors affecting equipment and cable products, including thermal effects, expressed in the destruction of insulation due to overheating and dynamic effects, expressed in physical destruction under the action of mechanical forces between the phases of conductors.

[0009] The technical problem is solved as follows. According to the invention, a device for distributing electrical energy comprises a housing with a power equipment chamber in which a block of power switches, a two-position switch-disconnector, busbars, and a cable chamber are located, wherein the vacuum chambers are located in the block of power switches, the busbars are electrically connected to the vacuum power switch through the two-position switch-disconnector, the cable chamber is configured to connect a load, the two-position disconnector-earthing switch is connected to the grounding circuit, and the device comprises a unit designed to test the cable line, electrically connected to the cable line through the two-position disconnector-earthing switch and the power vacuum switch, configured to access the cable line for testing the cable line, containing a metal plate,connected to the grounding circuit directly and through a two-position disconnector-grounder, and containing an arc protection device,

[0010] Common features with the analogue are the presence of a housing containing a power equipment chamber with a block of power switches, a two-position switch-disconnector, busbars, and a cable chamber, the location of vacuum chambers in the block of power switches, the connection of busbars with a vacuum power switch through a two-position switch-disconnector, the implementation of a cable chamber with the ability to connect a load, connection of a two-position disconnector-earthing switch to the grounding circuit.

[0011] In general, the technical solution differs from its analogue in that it contains a unit designed to conduct a test of a cable line, electrically connected to the cable line through a two-position disconnector-earthing switch and a power vacuum circuit breaker, configured to provide access to the cable line for testing the cable line, containing a metal plate connected to the grounding circuit directly and through a two-position disconnector-earthing switch, and containing an arc protection device.

[0012] In the first particular case of implementation, the unit intended for testing cable lines is designed with the possibility of connecting the testing device to one of the phases, while grounding the other phases in the same testing device is ensured.

[0013] In the second particular case of implementation, the unit intended for testing cable lines is designed and placed in such a way that testing of cable lines is carried out without access to the cable compartment and contact with cable lugs.

[0014] In the third particular case of implementation, the mutual arrangement and circuit design of the power equipment chamber is designed in such a way that the two-position disconnector-earthing switch is electrically connected to the busbars, to the power vacuum circuit breaker, and to the cable line testing unit, with the elements of the cell grounding device integrated into it.

[0015] During operation of electrical distribution devices, due to personnel error, voltage may be applied to a grounded cell, causing three-phase short circuits. In a standard cell design, during routine maintenance on the line, two of the three phases are grounded, and the third phase is connected to a cable line testing device. In the case described above, when voltage is applied to a grounded cell, the testing device may fail, and the two energized phases become a source of short circuits because they are grounded. Unlike the standard design, in the proposed solution, grounding of the two phases is performed in a cable line testing unit with an arc protection sensor installed within it.When short-circuit currents flow, the grounding device burns out, creating a flash that triggers the arc protection sensor installed in the cable line testing unit, which sends a command to trip the circuit breaker in the grounded bay. Since the circuit breaker is located schematically and structurally on the load side and is capable of interrupting short-circuit currents without damaging the electrical installation, the short circuit is localized and tripped in the grounded bay without interrupting power to the downstream substation.

[0016] If, due to personnel error, voltage is applied to the cell from the load side while connecting or disconnecting the test device to one of the cell phases or while installing a portable grounding device, personnel working on the site may be harmed. However, with the proposed device operation arrangement, the negative consequences for personnel will be significantly reduced, since the arc protection will signal a shutdown. Without an arc protection sensor, the shutdown time is increased by the tripping time of the relay protection. Moreover, since voltage is applied from the load side, and due to the distance of such a power source from the short circuit point, the relay protection response time is significantly increased. In some cases, the relay protection is unable to detect the flow of short-circuit current, putting the life and health of personnel servicing the site at risk.

[0017] If personnel erroneously close the grounded cell circuit breaker in a configuration where three phases are grounded using a plate, the plate and cell grounding busbar may not burn out due to the large cross-section and significant distance from the second power source, and the arc protection sensor will not operate. In this case, the short-circuit current is interrupted after the relay protection operates and a signal is sent to the grounded cell circuit breaker. Thus, the downstream substation and the consumer remain powered. In the proposed technical solution, if voltage is erroneously applied to the circuit, a short-circuit source also appears, since, according to the design, two phases are shorted to the cell grounding busbar in the compartment containing the cable line testing unit. However, when an arc protection sensor is installed in the compartment, the latter sends a signal to trip the circuit breaker for that cell.This ensures improved equipment reliability and personnel safety while maintaining cable line testing convenience. Power remains supplied to the downstream substation. The proposed technical solution, equipped with a cable line testing unit accessible from the front of the cubicle, allows for cable line testing without the need to access the open cable compartment.

[0018] This paper also discloses a method for testing a cable line. The technical solution described in the aforementioned Russian Federation Patent No. 2217851, "ETALON COMPLETE SWITCHGEAR DEVICE," was selected as an analog. However, although the connection between the proposed and known solutions is clearly visible, the problems they address differ. Therefore, the aforementioned technical solution was chosen to illustrate the current state of the art.

[0019] The problem that the proposed method is aimed at solving is maintaining power in the downstream cell in the event of power supply during work, as well as increasing the safety of routine maintenance, including in cases of unplanned power supply to a grounded cell.

[0020] The problem is solved as follows. A method for testing a cable line involves accessing a phase of the cable line through a unit designed for testing the cable line with a cable line testing device by removing the grounding metal plate located in the unit designed for testing the cable line, connecting one of the phases, connecting the cable line testing equipment, and grounding the remaining phases.

[0021] Cable line testing with a built-in cable line test unit eliminates direct access to cable lugs during cable line testing. The cubicle is equipped with a cable line test unit accessible from the front of the cubicle, eliminating the need to work in the open cable compartment. When testing a single cable line, if voltage is erroneously applied from the load side, a short circuit occurs in the compartment containing the cable line test unit, as the two remaining phases are shorted to the cubicle ground busbar. However, when an arc protection sensor is installed in the compartment, it signals the cubicle circuit breaker to trip. This improves reliability and safety while maintaining convenience, while maintaining power to the downstream substation.If voltage is erroneously applied to a grounded cell from the load side, the grounding plate of the cable line testing unit will become the source of a short circuit. In this case, the cell's protective relay is activated and the circuit breaker is tripped. Thus, the short circuit point is localized within a single cell.

[0022] The proposed invention is explained by the following figures:

[0023] Fig. 1 - Main elements of the cell of the one-way service assembly chamber equipped with a cable line testing unit.

[0024] Fig. 2 - exploded view of a cell of a one-way service assembly chamber equipped with a cable line testing unit.

[0025] The following positions are indicated on the figures:

[0026] 1 - cable line testing unit with grounding device;

[0027] 2 - power switch;

[0028] 3 - two-position disconnector-earthing switch;

[0029] 4 - busbars.

[0030] To understand the operating principles and features of various implementations of the invention, a description of the figures of the technical solution is provided below. Although the text of the description explains in detail the preferred embodiments of the technical solution, it should be understood that other embodiments of the invention are also possible. Accordingly, there is no need to limit the scope of legal protection of the technical solution solely to the presented implementations and lists of units and components. The invention may be implemented in other ways. However, when describing preferred embodiments of the technical solution, to ensure a clear understanding of the basic principles of the invention by those skilled in the art, it is necessary to clarify the terms used in the description.

[0031] It should be noted that the singular forms of device components and parts in the description and claims also represent plural forms, unless expressly stated otherwise. For example, a reference to a component of a device also refers to a set (multitude) of such components.

[0032] Also, when describing the preferred embodiments, specific terms are used for clarity. It is intended that the term be used in the broadest sense possible for those skilled in the art and includes all technical equivalents used in the same manner and for the same purpose. A cubicle is defined as a device designed to receive and distribute electrical energy in networks with an isolated neutral, typically with a rated voltage of 6 to 20 kV. However, the rated voltage may differ from the typical voltage. A power equipment chamber is defined as a sealed compartment within an enclosure with a built-in vacuum circuit breaker, earthing switch-disconnector, busbars, and elements providing mechanical connections between switching devices.A cable chamber is the part of a cell where the feeder or outgoing cable is connected to the cell's high-voltage terminals. In addition to cables, the chamber may also house transformer equipment. Busbars are electrical components used to connect cells into a switchgear section and distribute currents across individual power lines. A load is an electrical device connected to and powered by the electrical installation in question, specifically a cell, switchgear section, or substation. A cable line test unit is a device that allows cable line testing without the need for additional operational switching of cable lugs or disconnection of cable adapters, with the ability to perform maintenance on cable lines from the cell's front panel.The term "grounding circuit" refers to a set of cell components that equalize the potentials of the ground and conductors. An arc protection device is understood to be a fast-acting short-circuit protection device based on the prevention of an electric arc flash. A "vacuum arc-extinguishing chamber" or "vacuum interrupter" refers to a component designed for use in vacuum circuit breakers with rated voltages up to 20 kV. These chambers are suitable for frequent switching operations. The chamber is connected to the disconnector's moving contacts and the bushing adapter. The vacuum arc-extinguishing chamber interacts with the disconnector's moving contacts and the control drive of the vacuum circuit breaker. A two-position disconnector-earthing switch is designed for switching to the grounded position and to the operating position.

[0033] The words “consisting,” “comprising,” “including” mean that at least the specified component, element, part, or method step is present in the composition, object, or method, but do not exclude the presence of other components, materials, parts, method steps, even if such component, material, part, method step performs the same function as the specified one.

[0034] The materials from which the various elements of the present invention are made, as described below in the description of specific embodiment examples of the device, are typical, but not mandatory. The materials cited in these embodiment examples may be replaced by numerous similar materials that perform the same function as the material examples described.

[0035] The device is an EVOLUTION integrated switchgear, according to Fig. 1, which contains a cable line testing unit 1, which is installed in a sealed enclosure. The unit is equipped with a grounding device and provides access to cable lugs without additional operational switching and disconnecting cable adapters. By default, a plate connecting three phases is installed inside the unit, connected to the cell grounding circuit. In turn, the cell is connected to the grounding circuit of the substation in which it is installed. On the other hand, the unit is connected to the moving contacts of the two-position earthing switch disconnector 3. The vacuum arc-quenching chamber interacts with the moving contacts of the disconnector 3 and the control drive of the power vacuum circuit breaker. Busbars 4 connect the device to the electrical system. All generators or transformers, inputs and outgoing lines are connected to the busbars.Electrical energy enters the busbars and is distributed to individual outgoing lines. When the disconnector is switched to the "grounded" position, interaction occurs with the disconnector's moving contacts. After the disconnector is moved to the "grounded" position, circuit breaker 2 is moved to the "on" position, thereby electrically connecting the connected cable lines to the cable line testing unit and, through a metal plate (not shown) located in the cable line testing unit and connecting all three phases, to the grounding circuit. For routine maintenance, the plate is removed and a test rod is installed in one of the phases, to which the testing device is connected, while the other two phases are grounded. Additionally, an arc protection sensor is installed in the cable line testing unit; in the event of a spark or flash, it sends a signal to the relay protection and automation device of this cell.If voltage is erroneously applied from the load side (from the consumer) during maintenance on the cable line, the portable grounding device located in the cable line testing unit and two of the three grounding phases will become the source of a short circuit. The cable line testing device may also be the source of the short circuit. In this case, the arc protection sensor will trigger a tripping signal for circuit breaker 2. Thus, the short circuit is localized within a single cell automatically within a short period of time. If, due to the short circuit being located significantly away from the power source, the relay protection device fails to detect the short circuit, the portable grounding device will overheat and burn out. The arc protection sensor will detect the spark and trigger a tripping signal for circuit breaker 2.

[0036] This ensures the safety of testing personnel, and eliminates the need to disconnect the downstream substation from the other input to de-energize the cell. If testing is not being performed and the cell is simply grounded, the operating principle remains the same.

[0037] The embodiments of the present invention are not limited to the specific embodiment examples given above. Other embodiments of the technical solution may be proposed without departing from the spirit of the invention. The configuration and relative positioning of the device's components and elements may also vary, unless expressly stated in the description. However, certain configurations have been disclosed in this description. The embodiment examples disclosed above are provided to demonstrate the industrial applicability of the device and to provide a general impression of the capabilities of the proposed device and method. The scope of legal protection for the technical solution is determined by the claims, not the description provided, and all modifications made using equivalent features are covered by the legal protection of the present invention.

Claims

1. A device for distributing electrical energy, comprising a housing containing a power equipment chamber with a block of power switches, busbars and a two-position disconnector-earthing switch, a cable chamber, wherein the vacuum chambers are located in the block of power switches, the conductive buses are electrically connected to the vacuum power switch, the cable chamber is configured to connect a load, the two-position disconnector-earthing switch is connected to the grounding circuit, characterized in that it contains a unit intended for testing the cable line, electrically connected to the cable line through the two-position disconnector-earthing switch and a block of the power switch, configured to have access to the cable line for testing the cable line, containing a metal plate connected to the grounding circuit directly and through the two-position disconnector-earthing switch, and containing an arc protection device.

2. The device according to paragraph 1, characterized in that the unit intended for testing cable lines is designed with the possibility of connecting the testing device to one of the phases, while ensuring grounding of the other phases in the same testing device.

3. The device according to paragraph 1, characterized in that the unit intended for testing cable lines is designed and placed in such a way that testing of cable lines is carried out without access to the cable compartment and contact with cable lugs.

4. The device according to paragraph 1, characterized in that the mutual arrangement and circuit design of the power equipment chamber is designed in such a way that the two-position disconnector-earthing switch is electrically connected to the busbars, to the power vacuum circuit breaker, and to the cable line testing unit, with elements of the cell grounding device integrated into it.

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