Arc protection system installation optimization method, arc protection system and power system

Abstract

The application belongs to the technical field of power systems, and provides an arc protection system installation optimization method, an arc protection system and a power system. The application adopts a current signal cable to connect a photosensitive probe in a main bus switch compartment and a feeder bus switch compartment with a first main control unit and a second main control unit. The main bus switch compartment and the feeder bus switch compartment are provided with light strips. The application adopts a photosensitive signal cable to connect the main bus switch compartment and the feeder bus switch compartment with the first main control unit and the second main control unit. The application adopts a tripping signal cable to connect a bus coupler switch tripping outlet, a generator incoming line switch tripping outlet and a switch position with the first main control unit and the second main control unit. On the basis of current and arc signal judgment, the bus coupler switch tripping outlet, the generator incoming line switch tripping outlet and the switch position are connected with the first main control unit and the second main control unit through the tripping signal cable, so that the position of a power supply point can be determined, the problem that arc protection cannot accurately remove a faulty bus in a double bus wiring form is solved, and the problem of false removal of a normal power supply point is avoided.

Description

Technical Field

[0001] This invention belongs to the field of power system technology, and particularly relates to an optimized installation method for an arc flash protection system, an arc flash protection system, and a power system. Background Technology

[0002] The main busbar wiring of a certain electrical system is a double busbar segmented wiring configuration, with no baffle isolation between the front and rear switchgear. Currently, the mainstream busbar arc flash protection technology on the market uses arc flash sensors and fiber optic signal transmission to isolate the faulty busbar through light source criteria or light source + current criteria.

[0003] The inventors discovered that the mainstream arc flash protection devices currently on the market are applicable to single busbar and single busbar segmented wiring configurations, and are primarily used on medium-voltage busbars on the distribution side. When faced with power supply side dual busbar or 3 / 2 wiring configurations, or situations where there is no enclosed partition between the front and rear disconnector compartments, the arc flash protection devices become unsuitable. Some brands require expansion units and manual plugging and unplugging of fiber optic interfaces to address protection issues in power supply side dual busbar or 3 / 2 wiring configurations. This increases costs and may damage the fiber optic cable or adjacent interfaces, leading to malfunctions in the protection and control devices. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes an optimized installation method for arc flash protection systems. For dual-busbar or 3 / 2 busbar configurations, an auxiliary node for the power supply switch is introduced into the main control unit of the arc flash protection system. By adding a signal criterion based on the normally closed contact of the power supply switch, the location of the power supply point can be accurately determined. This eliminates the need for manual operation and is unaffected by whether the switch compartment is closed, effectively ensuring the correct disconnection of the faulty busbar under existing conditions.

[0005] To achieve the above objectives, firstly, taking a dual-busbar segmented wiring configuration as an example, this invention provides an optimized installation method for an arc flash protection system, employing the following technical solution:

[0006] The light strip and photosensitive element are wired and drilled in the switch compartment of the main busbar and bypass maintenance busbar. Bypass maintenance is also known as auxiliary busbar.

[0007] Lay power cables for the arc protection main control unit to ensure power supply to the device;

[0008] Current signal cables are used to connect each power source on the busbar to the first and second main control units; light strips are installed in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment, and the power sources include generators and main transformers, etc.

[0009] Photosensitive signal cables are used to connect each load in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment to the first main control unit and the second main control unit;

[0010] A trip signal cable is used to connect the trip outputs of the bus tie and sectionalizing switch, the generator incoming switch, and the main transformer switch to the first and second main control units.

[0011] Using trip signal cables, the position signals of the disconnect switches at each power point on the busbar are connected to the first and second main control units. Here, the cable is a single cable with different wires.

[0012] Furthermore, a new secondary cable tray is installed below the original secondary cable tray in the power system.

[0013] Furthermore, current signal cables and trip signal cables are laid along the new secondary cable trays.

[0014] Furthermore, the power cables laid in the newly installed secondary cable trays connect the branch switches of the interval switch power supply to the first main control unit and the second main control unit.

[0015] Furthermore, holes are made in the disconnector partitions of the main busbar disconnector and the auxiliary busbar disconnector to install photosensitive probes.

[0016] Furthermore, holes are drilled in the lower left and lower right corners of each busbar compartment.

[0017] Furthermore, a light strip surrounds each busbar segment, and photosensitive probes are installed at intervals along each busbar segment.

[0018] Furthermore, the generator disconnector position auxiliary contact and the generator outgoing line switch current signal are connected to the main control unit.

[0019] Furthermore, add guide rails and protective pressure plates; complete secondary wiring and mark the wires according to requirements to ensure correct polarity.

[0020] To achieve the above objectives, in a second aspect, the present invention also provides an arc flash protection system, employing the following technical solution to ensure that the failure of a single arc flash main control unit does not affect the current signal reception of other main control units, and is applicable to various operating modes:

[0021] An arc flash protection system includes a main control unit, a photosensitive probe, and a light strip;

[0022] The main control unit includes a first main control unit and a second main control unit respectively installed at the generator's incoming switch and the bus voltage transformer;

[0023] Current signal cables are used to connect the generator's incoming switch, bus tie switch, and bus section switch to the first and second main control units.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. This invention introduces the auxiliary contact signal of the disconnector into the arc flash main control unit. By determining the position of the power supply point on the bus, it solves the problem that the arc flash protection cannot accurately disconnect the faulty bus in the dual bus connection configuration, and avoids the problem of erroneous disconnection of the normal power supply point.

[0026] 2. This invention is also applicable to situations where the front and rear disconnector compartments of a double busbar are not closed. It solves the problem that when an arc is generated on the main busbar, the photosensitive probe on the auxiliary busbar may collect the light source and cause false tripping. By using a three-way criterion of current + arc light + disconnector position, the possibility of protection malfunction is eliminated.

[0027] 3. This invention solves the problem that a single arc light main control unit failure can prevent other main control units from acquiring current signals, thus causing all arc light protection systems to shut down. Attached Figure Description

[0028] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0029] Figure 1 This is a logic diagram of Embodiment 1 of the present invention;

[0030] Figure 2 The following is a prior art example of arc flash protection from a mainstream brand A on the market, as shown in Embodiment 1 of the present invention: a dual-bus segmented operation logic diagram.

[0031] Figure 3 The following is a prior art example of the B-type arc flash protection from a mainstream brand on the market, as shown in Embodiment 1 of the present invention: a dual-bus segmented operation logic diagram.

[0032] Figure 4 This is the dual-busbar segmentation operation logic of Embodiment 1 of the present invention;

[0033] Figure 5 This is a schematic diagram of the double busbar enclosed busbar compartment of Embodiment 1 of the present invention;

[0034] The components include: 1. Working busbar compartment; 2. Standby busbar compartment; 3. Working disconnect switch; 4. Standby disconnect switch; 5. Circuit breaker; 6. Current transformer.

[0035] Figure 6 This is a schematic diagram of the current signal wiring between the main control units in Embodiment 1 of the present invention. Detailed implementation method:

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0038] First, in existing products and technologies, such as Figure 2 The diagram shows the operation logic under a mainstream brand A arc flash protection system for a 10kV main busbar section III arc flash fault: The main control unit REA101, connected to incoming line switch 1318 or 1309, detects current information and simultaneously receives an arc flash signal from the arc flash sensor in the busbar compartment. The main control unit REA101 then trips incoming line switch 1318 or 1309. Additionally, the extension unit REA105, installed on sectionalizing switch 1302, also detects the light signal and simultaneously receives a current signal from the main control unit REA101. The extension unit REA105 then trips sectionalizing switch 1302, disconnecting the faulty 10kV main busbar section III and ensuring the normal operation of the remaining busbars.

[0039] Problems with Brand A arc flash protection: All power supply points on the 10kV main III busbar, including generators #3 and #8, as well as main transformer #2 and sectionalizing switch 1302, require manual adjustment of the fiber optic channels to determine their positions as the operating mode changes. This ensures that normal power supply points are not accidentally disconnected when the faulty busbar experiences arc flash. However, in power plants where operating modes are frequently adjusted, the fiber optic connectors of the main control unit's channels are frequently plugged and unplugged, which can easily damage them, leading to abnormalities in protection and control devices. Furthermore, the level of automation is not high, requiring manual adjustment. Therefore, it is not suitable for power plants or substations where operating modes are frequently adjusted.

[0040] Secondly, in existing products and technologies, such as Figure 3 The image shows an arc fault on the 10kV main III busbar under the arc protection of a mainstream brand B on the market: The main control unit 3NT detects an overcurrent signal and simultaneously receives an arc signal from the arc sensor of the III busbar compartment light strip or the III section 1 switch. The main control unit 3NT trips the No. 3 generator outgoing circuit breaker 1309, the No. 8 generator outgoing circuit breaker 1318, the No. 2 main transformer switch 1310, the sectionalizing switch 1302, and the main and auxiliary bus tie switch 1303.

[0041] Problems with Brand B arc protection: Power supply points such as generator #3 and generator #8 cannot be accurately located. When the power supply point is switched to the auxiliary busbar, if the main busbar fails, the power supply point will still trip. The reliability and accuracy do not meet the requirements of the double busbar connection. Moreover, if a main control unit or current cable fails, the other main control units will be unable to detect the current signal and will stop operating.

[0042] To address the above problems, this embodiment provides an optimized installation method for an arc flash protection system, such as... Figure 4 As shown, it mainly consists of an arc protection main control unit 2NT, photosensitive probes and light strips, current signal cables, and trip signal cables. The light strips surround each busbar section, and photosensitive probes are installed at intervals on each busbar section and connected to the main control unit.

[0043] Taking the 10kV main II busbar as an example, the auxiliary contact of the #2 generator disconnector position and the current signal of the #2 generator outgoing switch are converted into optical signals and connected to the main control unit 2NT via optical fiber, forming a three-criteria system of arcing light, current, and disconnector position. When an arcing light occurs on the faulty busbar, the main control unit detects the optical signal through a photosensitive probe, then detects that the fault short-circuit current has reached the starting value, and finally locates all power points on the faulty busbar through the disconnector position. Power points not on the faulty busbar must not be de-energized to prevent the accident from escalating. Only after the three parties confirm the location can the power points on the faulty busbar be accurately disconnected and the faulty busbar isolated.

[0044] Specifically, the extension unit of the incoming line to switch 1318 or 1309 detects current information and simultaneously receives an arc signal from the arc sensor in the busbar compartment. The main control unit then trips incoming line switch 1318 or 1309. Additionally, the extension unit installed on sectionalizing switch 1302 also detects the optical signal and simultaneously receives a current signal from the main unit. The extension unit will then trip sectionalizing switch 1302, disconnecting the faulty 10kV main III busbar and ensuring the normal operation of the remaining busbars.

[0045] The power supply points of the arc flash protection device's main control unit—specifically, the No. 3 generator outgoing circuit breaker 1309, the No. 8 generator outgoing circuit breaker 1318, the No. 2 main transformer switch 1310, and the sectionalizing switch 1302—are all connected to the auxiliary contact position of the power supply point 1 disconnect switch. This ensures that the power supply point switch is locked and tripped when the main III busbar is not connected. Simultaneously, it prevents all main control units from shutting down due to a failure in any main control unit or current cable caused by a disconnection of the current detection network.

[0046] In a power plant electrical system optimization and renovation project, the complex wiring configuration and flexible operational adjustment methods were addressed during the implementation of busbar arc flash protection upgrades. The complex wiring configuration refers to a double busbar segmentation system where the busbars are connected via sectionalizing switches and bus tie switches. The sectionalizing switches can be equipped with current-limiting reactors. Taking the 10kV main II busbar as an example, the specific steps are as follows:

[0047] S1. Installation of Secondary Cable Trays: Fabrication and installation of secondary cable trays for the 10kV main II section busbar. New secondary cable trays will be installed below the existing ones. Before installation, holes need to be drilled in the 16 disconnector compartments of this section for wire threading. Hole diameter... The opening position is 3cm below the original secondary cable tray at each interval. Requirements: all iron filings must be cleaned up at any time and must not be left in the switch cabinet; cleaned iron filings should be stored in a centralized manner; all holes must be of the same height and aligned left and right, with a deviation of ≤2mm.

[0048] S2. After drilling: Insert the die into the hole of one of the 16 knife switch compartments. PP threaded conduit is used to protect optical fibers and current cables, with 10mm protruding at each end. The plastic flanges are firmly bonded to the conduit and cabinet using strong adhesive. Requirements: The conduit must be free of damage or cracks. After bonding and curing for one hour, check the firmness of the secondary cable tray.

[0049] S3. Openings for light strip and photosensitive element wiring holes: Open the No. 1 and No. 2 disconnect switch compartment doors on all busbars. Open holes on the upper left of the front and rear partitions of the busbar disconnect switch compartments for installing the photosensitive probe. The hole diameter is... All iron filings must be cleaned up immediately and must not be left inside the switch cabinet; cleaned iron filings must be stored in a centralized location; all holes must be of uniform height and aligned left and right, with a deviation of ≤2mm.

[0050] S4. Workers climb onto the top of the busbar bridge and open all 16 main II busbar covers. After opening the covers, use [a tool / method] to [apply a tool / method] 10cm from the lower left and lower right corners in a certain direction within each busbar compartment. The drill bit will penetrate each busbar compartment for installing the optical strip. Requirements: all metal shavings must be cleaned up immediately and not left inside the switchgear; cleaned metal shavings must be stored in a designated area; all holes must be of uniform height and aligned horizontally, with a deviation ≤2mm.

[0051] S5 and 10kV auxiliary busbar light strip installation: Workers climb onto the top of the enclosed busbar bridge and open all 10kV auxiliary busbar covers. After opening the covers, use [a specific method / tool] to [do something] 10cm from the lower left and lower right corners of each busbar compartment. The drill bit will penetrate each busbar compartment for installing the optical strip. Requirements: All metal shavings must be cleaned up immediately and not left inside the switchgear; cleaned metal shavings must be stored in a centralized location; all holes must be of uniform height and aligned horizontally, with a deviation ≤2mm.

[0052] S6. Device Installation and Fixing: A rectangular hole is made on the secondary compartment door of the 1214 circuit breaker of motor #2 for installing the main control unit. Hole dimensions: 179mm high × 86mm wide. Requirements: The inner diameter of the hole is 1mm greater than the outer diameter of the device. The hole should be horizontal and vertical and should not affect the normal use of other components in the cabinet, such as terminal blocks and relays.

[0053] S7. Embed the main control unit into the hole and use the fixing clips to firmly fix the device to the cabinet door.

[0054] S8. Cable and Optical Fiber Laying: Each busbar section will be equipped with four types of optical fiber cables: power supply cables, current signal cables for the power switch bays in this section, photosensitive optical fibers, and trip signal cables.

[0055] S8.1 Power cable: Lay along the newly installed secondary cable tray to the two arc protection devices on the secondary compartment door of the No. 2 motor's outgoing circuit breaker 1214;

[0056] S8.2 Current signal cable: A 3*4+1*2.5mm2 current signal cable shall be laid along the newly added secondary cable tray from the secondary circuit compartment of the circuit breaker 1214 of the No. 2 motor, the bus tie 1204 of the main section II busbar, the sectionalizing switch 1113 of the main section I busbar and the main section II busbar, the No. 2 main transformer switch 1302, and the sectionalizing switch between the main section II busbar and the main section III busbar to the newly added arc flash protection device. Requirements: The cable shall be laid neatly, securely fixed and tied, and with sufficient slack.

[0057] S8.3, Photosensitive signal cable: Fiber optic cable shall be laid from the 1st and 2nd disconnector compartments of each busbar switch bay to the location of the newly added protection device. A photosensitive strip shall be laid from the top of the busbar compartment and run around the inside of the busbar compartment. The newly added arc protection device shall be laid at the beginning and end of the photosensitive strip. Requirements: The fiber optic cable shall be laid neatly and the bending radius of the fiber optic cable at all corners shall be >10cm.

[0058] S8.4, Trip output and disconnector position signal cable (disconnector position signal cable and trip signal cable share one cable): 10kV Main I section main and auxiliary bus tie cabinet switch 1112 trip output, No.1 generator incoming and outgoing line cabinet switch 1111 trip output and disconnector position, 10kV Main II section main and auxiliary bus tie switch 1204 trip output, No.2 generator incoming line switch 1214 trip output, 10kV Main III section main and auxiliary bus tie switch 1303 trip output, No.3 generator incoming line switch 1309 trip output and disconnector position, No.8 generator incoming line switch 1318 trip output and disconnector position.

[0059] S8.5 Output signal: Lay the output trip alarm signal from the two newly added arc flash protection devices to the ECS system monitoring and control device. When laying all optical cables, lay them horizontally and vertically, bind them firmly, and mark them on both sides. After laying, perform insulation tests. The insulation values ​​between phases and to ground should be >2MΩ.

[0060] Example 2:

[0061] This embodiment provides an arc flash protection system, including a main control unit, a photosensitive probe, and a light strip; the main control unit includes a first main control unit and a second main control unit respectively installed at the generator's incoming line switch and the bus voltage transformer;

[0062] A current signal cable is used to connect the photosensitive probes in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment to the first main control unit and the second main control unit, respectively; light strips are installed in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment;

[0063] Photosensitive signal cables are used to connect the main busbar disconnector compartment and the auxiliary busbar disconnector compartment to the first main control unit and the second main control unit, respectively; current signal cables are used to connect the generator incoming switch, bus tie switch and busbar sectionalizing switch to the first main control unit and the second main control unit.

[0064] Using trip signal cables, the trip output of the bus tie switch, the trip output of the generator incoming switch, and the disconnect switch are connected to the first main control unit and the second main control unit, respectively;

[0065] Using current signal cables, the generator's incoming line switch, bus tie switch, and bus sectionalizing switch are connected to the first and second main control units, as follows: Figure 6 As shown, when any main control unit, such as A1, fails and exits, the remaining four main control units can still collect current signals from each other.

[0066] Example 3:

[0067] This embodiment provides a power system that employs the arc flash protection system described in Embodiment 2.

[0068] This embodiment improves the accuracy of fault busbar location by adding auxiliary contacts for the disconnect switch, thus preventing false tripping of arc flash protection. It also saves costs and expands the applicable electrical main wiring range for arc flash protection. Addressing the limitation that arc flash protection is only applicable to single-busbar wiring configurations in power distribution systems and cannot achieve accurate and convenient operation in double-busbar or 3 / 2 wiring configurations, this embodiment introduces auxiliary contacts for the power supply point disconnect switch to determine the power supply point location. This solves the problem of arc flash protection's inability to accurately disconnect faulty busbars in double-busbar wiring configurations and avoids the problem of false disconnection of normal power supply points.

Claims

1. An optimized installation method for arc flash protection systems, characterized in that, include: A current signal cable is used to connect the photosensitive probes in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment to the first main control unit and the second main control unit, respectively; light strips are installed in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment; Photosensitive signal cables are used to connect the main busbar disconnector compartment and the auxiliary busbar disconnector compartment to the first main control unit and the second main control unit, respectively. Using trip signal cables, the trip output of the bus tie switch, the trip output of the generator incoming switch, and the position signal of the disconnect switch are connected to the first main control unit and the second main control unit, respectively; Connect the auxiliary contact signals of the disconnect switch positions of each power source point of the generator and main transformer to the main control unit where the corresponding power source point is located; the disconnect switch position signal cable and the trip signal cable share a single cable; A new secondary cable tray is installed below the original secondary cable tray in the power system; current signal cables and trip signal cables are laid along the new secondary cable tray. When an arc occurs on the faulty bus, the main control unit detects the light signal through the photosensitive probe, then detects that the fault short-circuit current has reached the start value, and finally locates all power points on the faulty bus by the position of the disconnect switch. Power points not on the faulty bus must not be de-energized to prevent the accident from escalating. Only after the three parties confirm the connection can the power points on the faulty bus be accurately disconnected and the faulty bus isolated.

2. The arc flash protection system installation optimization method as described in claim 1, characterized in that, Power cables are laid through new secondary cable trays to connect the branch switches of the interval switch power supply to the first and second main control units.

3. The arc flash protection system installation optimization method as described in claim 1, characterized in that, Holes are drilled in the disconnector partitions of the main busbar disconnector and the auxiliary busbar disconnector to install photosensitive probes.

4. The arc flash protection system installation optimization method as described in claim 3, characterized in that, Drill holes in the lower left and lower right corners of each busbar compartment and install optical strips.

5. The arc flash protection system installation optimization method as described in claim 4, characterized in that, A light strip surrounds each busbar segment, and photosensitive probes are installed at intervals along each busbar segment.

6. The arc flash protection system installation optimization method as described in claim 1, characterized in that, Connect the generator disconnector position auxiliary contact and the generator outgoing line switch current signal to the main control unit.

7. An arc flash protection system, comprising a main control unit, a photosensitive probe, and a light strip; the photosensitive probe is disposed in the main busbar disconnect switch compartment and the auxiliary busbar disconnect switch compartment, and the light strip is disposed in the main busbar disconnect switch compartment and the auxiliary busbar disconnect switch compartment; The main control unit includes a first main control unit and a second main control unit respectively installed at the generator's incoming switch and the bus voltage transformer; A current signal cable is used to connect the photosensitive probes in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment to the first main control unit and the second main control unit, respectively; light strips are installed in the main busbar disconnector compartment and the auxiliary busbar disconnector compartment; Photosensitive signal cables are used to connect the main busbar disconnector compartment and the auxiliary busbar disconnector compartment to the first main control unit and the second main control unit, respectively; current signal cables are used to connect the generator incoming switch, bus tie switch and busbar sectionalizing switch to the first main control unit and the second main control unit. Using trip signal cables, the trip output of the bus tie switch, the trip output of the generator incoming switch, and the position signal of the disconnect switch are connected to the first main control unit and the second main control unit, respectively; The disconnector position signal cable and the trip signal cable share the same cable. A new secondary cable tray is installed below the original secondary cable tray in the power system; current signal cables and trip signal cables are laid along the new secondary cable tray. When an arc occurs on the faulty bus, the main control unit detects the light signal through the photosensitive probe, then detects that the fault short-circuit current has reached the start value, and finally locates all power points on the faulty bus by the position of the disconnect switch. Power points not on the faulty bus must not be de-energized to prevent the accident from escalating. Only after the three parties confirm the connection can the power points on the faulty bus be accurately disconnected and the faulty bus isolated.

8. An electric power system, characterized in that, The arc protection system as described in claim 7 is adopted.

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