Segmented networking and redundancy protection method for steel sintering hot rolling high-voltage power distribution system

Abstract

This invention discloses a segmented networking and redundant protection method for a high-voltage power distribution system in steel sintering and hot rolling mills. The method includes: deploying a segmented differentiated network, specifically segmenting and partitioning the 10kV power distribution system of the steel plant's sintering main control building and the 110kV / 35kV switchgear power distribution system of the hot rolling workshop; constructing a three-level redundant protection system, including a three-level hierarchical redundant protection architecture consisting of automatic dual-power switching protection at the power supply level, bus tie interlocking protection at the busbar level, and microcomputer-based integrated protection tripping protection at the load level; configuring dedicated protection modules for high-power loads, specifically setting up dedicated reactive power compensation modules and high-voltage soft-start protection modules to address the impact load characteristics of high-power sintering fans and high-power hot rolling mills; and establishing a real-time fault linkage mechanism for background monitoring, including unifying the high-voltage cabinets, dual-power switching devices, bus tie interlocking protection devices, microcomputer-based integrated protection, reactive power compensation modules, and soft-start protection modules into the background monitoring system. A corresponding system is also disclosed.

Description

Technical Field

[0001] This invention relates to the field of high-voltage power distribution technology in the iron and steel metallurgy industry, specifically to a segmented networking and redundant protection method for a high-voltage power distribution system for sintering and hot rolling in iron and steel plants. It is particularly applicable to the networking and protection design of a 10kV non-standard power distribution system in the sintering main control building of an iron and steel plant and a 110kV / 35kV switchgear in hot rolling. Background Technology

[0002] As a pillar industry of the national economy, the steel industry relies on sintering and hot rolling as its core production processes. The stable operation of its power distribution system directly determines the continuity and safety of steel production. The core load of the sintering process consists of high-power sintering fans, main exhaust fans, and dust removal fans (1000-3000kW per unit), characterized by stable load, large start-up impact, and high requirements for continuous operation. The power distribution voltage is mainly 10kV. The core load of the hot rolling process consists of finishing mills, roughing mills, and coilers (2000-5000kW per unit), characterized by large impact loads, severe power fluctuations, and concentrated load zones. The power distribution voltage adopts two levels: 110kV and 35kV, with 35kV directly supplying power to the main drive of the rolling mill.

[0003] The existing 10kV power distribution systems in the sintering main control buildings of steel plants mostly adopt a single busbar without segmentation or with simple segmentation and single power supply mode. The 110kV / 35kV power distribution systems in hot rolling mills mostly adopt a general networking method based on voltage level, which has the following core technical defects:

[0004] 1. Single power supply failure can easily lead to production interruption: The sintering 10kV system is powered by a single power supply. When the power supply side fails (line short circuit, transformer tripping, incoming line undervoltage), there is no backup power supply switching mechanism, which directly leads to the shutdown of the sintering fan and the shutdown of the entire sintering production line. The hot rolling 35kV system has a single busbar segmented but no reliable bus tie interlocking protection. When a section of the busbar fails, the bus tie switch cannot close quickly, and the fault spreads to the entire section of the busbar, causing the roughing or finishing rolling area to shut down. The direct economic loss from a single shutdown can reach several million yuan.

[0005] 2. Poor load adaptability of different processes: The load of the sintering process is stable but the start-up impact is large, while the load of the hot rolling process fluctuates violently and the impact load is concentrated. The existing network configuration is not designed according to the different characteristics of the process load. The 10kV busbar of sintering is not segmented, resulting in a large range of fault impact. The 35kV busbar of hot rolling is not zoned according to "finishing rolling / roughing rolling / feeder". The impact load of roughing rolling interferes with the power supply quality of precision equipment in finishing rolling, causing problems such as mill vibration and reduced product precision.

[0006] 3. The protection system is only single-level and lacks strong linkage: Most existing protection systems are configured with single-level microcomputer integrated protection at the load level, lacking redundant protection at the power supply and busbar levels, and lacking a multi-level redundancy mechanism of "dual power supply switching + bus tie interlocking + load integrated protection"; high-power sintering fans and hot rolling mills are only equipped with basic overcurrent protection, without dedicated reactive power compensation and soft-start protection modules. The inrush current during startup reaches 5-8 times the rated current, frequently causing sudden drops in busbar voltage and false tripping of protection; the background monitoring system is not linked in real time with the high-voltage cabinet and integrated protection system, and it is impossible to quickly locate and isolate faults after they occur, resulting in low handling efficiency.

[0007] To address the above problems, existing technologies have proposed some improvement solutions, but all of them have obvious limitations:

[0008] 1. Simple parallel connection of dual power supplies: Some steel plants have configured dual power supplies for the 10kV sintering system, but they use a simple parallel connection method without automatic switching logic. The switching requires manual operation and the switching time is long (≥30 minutes), which cannot meet the requirements of continuous production. In addition, there is no busbar segmentation design, so a fault will still cause the entire system to shut down.

[0009] 2. Busbar sectional protection scheme without interlocking: The hot-rolled 35kV system adopts busbar sectionalization, but the bus tie switch has no interlocking protection device and is only equipped with manual closing function. When a section of the busbar is faulty, it is necessary to manually judge the fault, manually open the faulty section switch, and close the bus tie switch. The fault handling time is long (≥15 minutes), the fault is easy to spread, and it is impossible to achieve rapid isolation and power restoration.

[0010] 3. Single protection configuration scheme: Some high-voltage switchgear is equipped with microcomputer integrated protection, but it only realizes overcurrent and instantaneous overcurrent protection at the load level, without dual power supply switching protection at the power supply level or bus tie interlocking protection at the busbar level. The protection level is single and there is no redundancy backup. When the integrated protection device fails, the protection function is lost. High-power loads do not have dedicated reactive power compensation and soft start modules, resulting in large starting inrush current and affecting the stability of the power grid.

[0011] 4. Undifferentiated network design: The existing network scheme does not distinguish the load characteristics of sintering and hot rolling processes. The sintering 10kV system is not segmented, resulting in a large fault impact range. The hot rolling 35kV system is not zoned, resulting in severe load interference. It cannot adapt to the load requirements of different processes, resulting in low power supply quality and reliability.

[0012] In summary, existing high-voltage power distribution technology for steel sintering and hot rolling suffers from four core defects: a single networking method, poor load adaptability, a weak protection system, and insufficient linkage. These shortcomings fail to meet the requirements of continuous production and high-reliability power supply for steel enterprises. Currently, there is no complete technical solution for sintering 10kV and hot rolling 110kV / 35kV systems that combines segmented networking, three-level redundancy protection, and differentiated load adaptability. Furthermore, there is no technical solution adapted to the networking characteristics of medium-voltage switchgear such as KYN28A-12 and enabling real-time linkage for backend monitoring. Therefore, developing a high-voltage power distribution method that adapts to the load characteristics of different processes in sintering / hot rolling, possesses multi-level redundancy protection, and offers flexible and reliable networking has significant engineering application value and practical significance. Summary of the Invention

[0013] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a segmented networking and redundant protection method for high-voltage power distribution systems in hot rolling mills for steel sintering. This method addresses the problems of easy production stoppages due to single-power-source failures, poor load adaptability, single protection level, and weak linkage in existing technologies, achieving the following objectives:

[0014] 1. Design differentiated segmented networking schemes for different load characteristics of sintering and hot rolling processes, adapting to the networking characteristics of KYN28A-12 and other centrally located high-voltage switchgear, reducing the scope of fault impact and improving load adaptability.

[0015] 2. Construct a three-level redundant protection system consisting of "automatic switching between dual power supplies at the power supply level + interlocking protection of bus tie cabinets at the busbar level + tripping of microcomputer-based integrated protection at the load level" to achieve multi-level isolation and rapid handling of faults and improve power supply reliability.

[0016] 3. Equip high-power sintering fans and hot rolling mills with dedicated reactive power compensation and soft-start protection modules to reduce starting inrush current, stabilize bus voltage, and improve power supply quality.

[0017] 4. Enable real-time linkage between the background monitoring system and the high-voltage cabinet, integrated protection system, and protection modules to quickly locate and isolate faults, thereby improving the efficiency of fault handling.

[0018] The first aspect of this invention is to provide a segmented networking and redundant protection method for a high-voltage power distribution system for hot-rolled sintered steel, comprising:

[0019] S1, deploying segmented and differentiated network, including: for the 10kV power distribution system of the sintering main control building and the 110kV / 35kV switchgear power distribution system of the hot rolling workshop, differentiated segmented and zoned network is carried out according to the load characteristics of different processes in sintering and hot rolling; the sintering 10kV system is divided into two independent busbars, and the hot rolling 110kV / 35kV system is networked according to the functional zones of finishing rolling, roughing rolling, and feeder; bus tie cabinets are configured between each segment and zone busbar, adapted to the structural characteristics of KYN28A-12 medium-voltage switchgear, to achieve normal independent operation of each busbar and interconnection and load transfer in case of fault;

[0020] S2, construct a three-level redundant protection system, including: building a three-level redundant protection architecture of power supply layer dual power supply automatic switching protection, busbar layer bus tie cabinet interlocking protection and load layer microcomputer integrated protection trip protection. From top to bottom, it completes power supply side fault redundancy switching, busbar side fault interlocking isolation and load side fault accurate tripping in sequence, forming a multi-level linkage protection closed loop.

[0021] S3 is equipped with a dedicated protection module for high-power loads, including: a dedicated reactive power compensation module and a high-voltage soft start protection module respectively set up for the impact load characteristics of high-power sintering fans and high-power hot rolling mills, which are used to realize dynamic reactive power compensation for high-power loads, suppression of starting inrush current and overload fault protection.

[0022] S4 establishes a real-time fault linkage mechanism for background monitoring, including: connecting high-voltage cabinets, dual-power switching devices, bus tie interlocking protection devices, microcomputer integrated protection, reactive power compensation modules and soft-start protection modules to the background monitoring system through industrial Ethernet communication protocol, so as to realize real-time acquisition of all equipment operating parameters, automatic fault location, protection action linkage alarm and remote operation and maintenance management.

[0023] Preferably, the step S1 of dividing the sintering 10kV system into two independent busbars includes: adopting a single busbar segmentation and dual power supply mode, dividing the 10kV busbar into busbar section I and busbar section II, with a KYN28A-12 medium-voltage switchgear as a bus tie cabinet between the two busbars; the dual power supply is a dual-circuit independent 10kV power supply, respectively drawn from different upstream 35kV substations, each with a capacity of 20MVA, and each is 100% standby; wherein, the load of busbar section I is the core production load of the sintering fan and the main exhaust fan, and the load of busbar section II is the standby sintering fan, dust removal fan and common load; during normal operation, the bus tie cabinet switch is in the open state, the two busbars operate independently, and the load is evenly distributed.

[0024] Preferably, the hot-rolled 110kV / 35kV system described in step S1, which is divided into finishing mill, roughing mill, and feeder functional zones for busbar networking, includes: a composite mode of 110kV single busbar segmentation and 35kV functional zone networking; the 110kV system is equipped with dual-circuit independent power supplies, respectively drawn from different busbars of the upstream 220kV substation, each with a capacity of 50MVA, serving as backups for each other; the 110kV busbar segmentation switch uses a ZF28-126GIS high-voltage switchgear; the 35kV... The kV system is divided into three independent busbar sections: "finishing mill / roughing mill / feeder". Each busbar section uses a KYN28A-12 centrally mounted high-voltage switchgear for networking. The load on the finishing mill section busbar is the finishing mill and finishing mill cooling pump set. The load on the roughing mill section busbar is the roughing mill and roughing mill main drive. The load on the feeder section busbar is the coiler, conveyor rollers and common loads. Each busbar section is equipped with a KYN28A-12 type bus tie switch. During normal operation, the switches of each bus tie switch are open, and each busbar section operates independently to avoid load interference.

[0025] Preferably, the bus tie cabinets mentioned in step S1 are all equipped with electric operating mechanisms, mechanical interlocking devices and electrical interlocking devices, supporting dual control of remote operation and local operation; all bus tie cabinets adopt the top-in and top-out wiring method, which matches the size of the corresponding high-voltage cabinet and can be directly installed in parallel.

[0026] Preferably, the specific implementation steps of the power layer dual-power automatic switching protection in step S2 are as follows:

[0027] Automatic switching devices (ATS) of corresponding specifications are configured for the 10kV dual power supply for sintering and the 110kV dual power supply for hot rolling. The ATS is used to monitor the three-phase voltage, frequency and phase of the dual power supply in real time.

[0028] The switching logic between the main power supply and the backup power supply is set as follows: when the main power supply is working normally, the backup power supply is in standby mode and the bus tie switch remains open; when the main power supply experiences a voltage loss, undervoltage, overvoltage, phase loss, or frequency abnormality fault, and the fault duration is ≥0.5s, the ATS immediately issues a trip command to disconnect the main power supply switch.

[0029] After the automatic switching device (ATS) issues a trip command, it issues a closing command after a 20ms delay, closing the backup power switch and completing the seamless switching between the two power sources. The total switching time is ≤100ms. At the same time, the ATS is equipped with a dual interlocking mechanism of mechanical and electrical interlocks. When there is a fault in the backup power supply, the switching function is automatically blocked.

[0030] Preferably, the specific implementation steps of the busbar layer bus tie cabinet interlocking protection in step S2 are as follows:

[0031] Each section and zone busbar is equipped with a busbar tie cabinet interlocking protection device, which monitors the voltage, incoming current and busbar tie switch status of the corresponding busbar in real time.

[0032] Interlocking protection logic is set: when a short circuit, undervoltage, or overcurrent fault occurs in a certain section or zone bus, and the fault duration is ≥0.3s, the interlocking protection device immediately issues a trip command to disconnect the incoming switch of the fault section;

[0033] After disconnecting the incoming switch of the faulty section, a closing command is issued after a 10ms delay, closing the corresponding bus tie switch and transferring the load of the faulty section to the normally operating bus, thus achieving fault isolation. The total protection action time is ≤150ms. Among them, the bus interlocking priority of the hot rolling 35kV system is set as finishing rolling section > roughing rolling section > feeder section, and the bus interlocking priority of the sintering 10kV system is set as section I bus > section II bus, giving priority to ensuring power supply to the core production load. The bus tie switch interlocking protection device adopts a dual-CPU redundant design. When the main CPU fails, the backup CPU automatically starts operation.

[0034] Preferably, the specific implementation steps of the load layer microcomputer integrated protection trip protection in step S2 are as follows:

[0035] Each high-pressure load in the sintering and hot rolling system is equipped with a separate microcomputer integrated protection device. Each device integrates overcurrent protection, instantaneous overcurrent protection, overvoltage protection, undervoltage protection, phase loss protection, grounding protection and overheat protection functions. The protection parameters can be set remotely through the background monitoring system or manually on site.

[0036] Set the protection operation parameters, including: overcurrent protection operating current of 1.2-1.5 times the rated load current, operating delay of 0.5-2s; instantaneous overcurrent protection operating current of 5-8 times the rated load current, instantaneous operation; overvoltage protection operating voltage of 1.2 times the rated voltage, operating delay of 1s; undervoltage protection operating voltage of 0.7 times the rated voltage, operating delay of 0.5s; grounding protection operating current ≥100mA, instantaneous operation.

[0037] When any of the above-mentioned faults occur on the load side, the microcomputer integrated protection device immediately issues a trip command to disconnect the corresponding load switch; after the fault is cleared, the load power supply is restored through remote reset via the background monitoring system or manual reset on site; the microcomputer integrated protection device is powered by dual power supplies of DC 220V and AC 100V and supports dual Ethernet communication to ensure that fault signals are uploaded to the background monitoring system in real time.

[0038] Configure dedicated protection modules for high-power loads, including: dedicated reactive power compensation modules and high-voltage soft-start protection modules for the impact load characteristics of high-power sintering fans and high-power hot rolling mills, respectively, to achieve dynamic reactive power compensation for high-power loads, suppression of starting inrush current, and overload fault protection.

[0039] Preferably, the configuration of the high-power load dedicated protection module in step S3 includes:

[0040] A dedicated reactive power compensation module is configured, including: using a dynamic reactive power compensation device (SVG) as the reactive power compensation module. The SVG has a response time ≤20ms, a compensation range of 0 to the corresponding rated capacity, and monitors the load-side power factor and bus voltage in real time. When the power factor <0.95 or the bus voltage fluctuation exceeds the allowable range, it automatically outputs reactive power to achieve dynamic compensation. The SVG integrates overcurrent, overvoltage, and overheat protection functions. It automatically exits operation in case of failure without affecting the normal operation of the main circuit. It adopts a cabinet structure with dimensions consistent with the KYN28A-12 medium-voltage switchgear and can be directly installed in parallel.

[0041] The soft start protection module is configured, including: using a high-voltage solid-state soft starter as the soft start protection module; the soft start protection module integrates overcurrent, overvoltage, undervoltage, phase loss, grounding, overheating and motor overload protection functions, and is linked with the load layer microcomputer integrated protection device to form dual protection, and adopts a cabinet structure with top-in and top-out wiring.

[0042] Preferably, the establishment of the real-time linkage mechanism for background monitoring faults in step S4 includes:

[0043] Hardware configuration includes: an industrial-grade server for the background monitoring system, equipped with dual monitors and audible and visual alarms; and an intelligent communication gateway configured on-site, supporting ModbusTCP and IEC61850 communication protocols, for collecting operating data and fault signals from high-voltage switchgear, dual-power automatic switching devices, bus tie interlock protection devices, microcomputer integrated protection devices, SVG reactive power compensation modules, and high-voltage solid-state soft starters.

[0044] Data acquisition and monitoring are carried out, including: the background monitoring system collects power supply voltage, current, frequency, bus voltage, current, high voltage switch status, operation status of each protection device, SVG compensation capacity, soft starter operating parameters, load power and temperature parameters in real time through the intelligent communication gateway.

[0045] The system implements coordinated fault handling, including: when a power supply layer fault, busbar layer fault, load layer fault, or protection module fault occurs in the system, the background monitoring system immediately receives the fault signal, automatically locates the fault location, identifies the fault type, controls the audible and visual alarms to issue alarm signals, and automatically generates a fault report, recording the fault time, fault parameters, and protection action status; at the same time, the system, based on the fault type, coordinates with the corresponding protection devices to complete fault isolation, load transfer, or equipment shutdown operations.

[0046] Remote operation and maintenance management includes: the back-end monitoring system supports remote login, parameter setting, switch operation, and fault reset for operation and maintenance personnel.

[0047] A second aspect of the present invention provides a segmented networking and redundant protection system for a high-voltage power distribution system in a hot-rolled sintering steel industry, for implementing the method of the first aspect, comprising:

[0048] The segmented differentiated networking module (101) is used to deploy segmented differentiated networks, including: for the 10kV power distribution system of the sintering main control building and the 110kV / 35kV switchgear power distribution system of the hot rolling workshop, differentiated segmented and zoned networking is carried out according to the load characteristics of different processes of sintering and hot rolling; the sintering 10kV system is divided into two independent busbars, and the hot rolling 110kV / 35kV system is networked according to the functions of finishing rolling, roughing rolling and feeder. Bus tie cabinets are configured between each segment and zone busbar, which are adapted to the structural characteristics of KYN28A-12 medium-voltage switchgear, so as to realize the normal independent operation of each busbar and the interconnection and load transfer in case of fault;

[0049] The three-level redundancy protection system construction module (102) is used to construct a three-level redundancy protection system, including: building a three-level hierarchical redundancy protection architecture of power supply layer dual power supply automatic switching protection, busbar layer bus tie cabinet interlocking protection and load layer microcomputer integrated protection tripping protection. From top to bottom, it completes power supply side fault redundancy switching, busbar side fault interlocking isolation and load side fault accurate tripping in sequence, forming a multi-level linkage protection closed loop.

[0050] A high-power load dedicated protection module configuration module (103) is used to configure a high-power load dedicated protection module, including: for the impact load characteristics of sintering high-power fans and hot rolling high-power mills, a dedicated reactive power compensation module and a high-voltage soft start protection module are respectively set up to realize high-power load reactive power dynamic compensation, starting impact current suppression and overload fault protection;

[0051] The background monitoring fault real-time linkage mechanism construction module (104) is used to build a background monitoring fault real-time linkage mechanism, including: connecting the high voltage cabinet, dual power supply switching device, bus tie interlock protection device, microcomputer integrated protection, reactive power compensation module and soft start protection module to the background monitoring system through the industrial Ethernet communication protocol, so as to realize the real-time acquisition of all equipment operating parameters, automatic fault location, protection action linkage alarm and remote operation and maintenance management.

[0052] The beneficial effects of the method and system of the present invention are as follows:

[0053] The method of this invention is applicable to the networking and protection design of 10kV non-standard power distribution systems in the sintering main control building of steel plants and 110kV / 35kV switchgear in hot rolling mills. The method is compatible with mainstream medium-voltage switchgear such as KYN28A-12, requires no customized special equipment, has low modification costs, strong compatibility, and can be directly applied to the modification of existing power distribution systems or the design of new power distribution systems in steel plants. It has high application value and specifically includes:

[0054] (1) Segmented networking with strong load adaptability and small fault impact range: This invention is designed with segmented networking to address the differences in load characteristics between sintering and hot rolling processes. The sintering 10kV system is segmented by double busbars, and the hot rolling 35kV system is divided into "finishing / roughing / feeder" zones, which are adapted to the networking characteristics of KYN28A-12 medium-voltage switchgear. During normal operation, the load is evenly distributed and operates independently. In case of a fault, the fault is quickly isolated, reducing the fault impact range by more than 70% and avoiding a complete system shutdown. The hot rolling zoned networking effectively suppresses the interference of roughing impact load on finishing precision equipment, improving product accuracy by more than 15%.

[0055] (2) Three-level redundant protection, high power supply reliability and fast fault handling: The present invention constructs a three-level redundant protection system of "automatic switching of dual power supply at the power supply layer + interlocking protection of bus tie cabinet at the bus layer + microcomputer integrated protection tripping at the load layer". The three layers of protection are redundant and isolated from each other, and the total protection action time is ≤200ms; seamless switching of dual power supply in case of power failure (≤100ms), rapid load transfer in case of bus failure (≤150ms), and instantaneous tripping isolation in case of load failure (≤50ms). The power supply reliability is increased from the existing 99.9% to 99.999%, the average annual power outage time is shortened to less than 5 minutes, production interruption caused by single power supply failure is avoided, and the loss of a single production stoppage is reduced by more than 90%.

[0056] (3) Dedicated protection for high-power loads, excellent power supply quality, and long equipment life: This invention is equipped with a dedicated SVG reactive power compensation and high-voltage solid-state soft start module for sintering fans and hot rolling mills. The SVG dynamically compensates for reactive power, and the power factor is stable at ≥0.95. The bus voltage fluctuation is controlled within ±2%. The soft starter reduces the starting impact current from 5-8 times the rated current to 2-2.5 times, avoiding sudden drops in bus voltage and false tripping of protection circuits. The motor starting loss is reduced by 60%, the equipment service life is extended by more than 30%, and the equipment maintenance cost and downtime are reduced.

[0057] (4) Real-time linkage in the background, high operation and maintenance efficiency, and accurate fault location: This invention realizes real-time linkage between the background monitoring system and all power distribution equipment and protection modules. The monitoring response time is ≤100ms. After a fault occurs, it is automatically located, isolated, and alarmed, and a fault report is generated. Operation and maintenance personnel can remotely monitor and handle the fault. The fault handling time is shortened from the existing 30 minutes to less than 5 minutes, the operation and maintenance efficiency is improved by more than 80%, the labor intensity of operation and maintenance is reduced, and human operation errors are reduced.

[0058] (5) Strong adaptability and high application value: The networking and protection design of this invention is compatible with mainstream medium-voltage switchgear such as KYN28A-12, without the need for customized equipment, and has low transformation cost and strong compatibility; it is applicable to the 10kV sintering and 110kV / 35kV power distribution systems of all steel plants, especially suitable for the transformation of non-standard power distribution systems. The technology promotion threshold is low and the application scope is wide. It is in line with the development trend of intelligent manufacturing, energy saving and cost reduction in the steel industry, and has significant economic and social benefits. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0060] Figure 1 A flowchart illustrating the segmented networking and redundant protection method for a high-voltage power distribution system for hot-rolled sintered steel according to an embodiment of the present invention.

[0061] Figure 2 This is a diagram of the segmented networking and redundant protection system architecture for a high-voltage power distribution system in hot rolling and sintering of steel. Detailed Implementation

[0062] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0064] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0065] like Figure 1 As shown, the first aspect of this embodiment is to provide a segmented networking and redundant protection method for a high-voltage power distribution system for hot rolling mill sintering of steel, including:

[0066] S1, deploying segmented and differentiated network, including: for the 10kV power distribution system of the sintering main control building and the 110kV / 35kV switchgear power distribution system of the hot rolling workshop, differentiated segmented and zoned network is carried out according to the load characteristics of different processes in sintering and hot rolling; the sintering 10kV system is divided into two independent busbars, and the hot rolling 110kV / 35kV system is networked according to the functional zones of finishing rolling, roughing rolling, and feeder; bus tie cabinets are configured between each segment and zone busbar, adapted to the structural characteristics of KYN28A-12 medium-voltage switchgear, to achieve normal independent operation of each busbar and interconnection and load transfer in case of fault;

[0067] S2, construct a three-level redundant protection system, including: building a three-level redundant protection architecture of power supply layer dual power supply automatic switching protection, busbar layer bus tie cabinet interlocking protection and load layer microcomputer integrated protection trip protection, which completes power supply side fault redundancy switching, busbar side fault interlocking isolation and load side fault accurate tripping in sequence from top to bottom, forming a multi-level linkage protection closed loop.

[0068] S3 is equipped with a dedicated protection module for high-power loads, including: a dedicated reactive power compensation module and a high-voltage soft start protection module respectively set up for the impact load characteristics of high-power sintering fans and high-power hot rolling mills, to realize dynamic reactive power compensation for high-power loads, suppression of starting inrush current and overload fault protection.

[0069] S4 establishes a real-time fault linkage mechanism for background monitoring, including: unifying the high-voltage cabinet, dual power supply switching device, bus tie interlock protection device, microcomputer integrated protection, reactive power compensation module and soft start protection module into the background monitoring system through industrial Ethernet communication protocol, so as to realize real-time acquisition of all equipment operating parameters, automatic fault location, protection action linkage alarm and remote operation and maintenance management.

[0070] Preferably, the step S1 of dividing the sintering 10kV system into two independent busbars includes: adopting a single busbar segmentation and dual power supply mode, dividing the 10kV busbar into busbar section I and busbar section II, with a KYN28A-12 medium-voltage switchgear as a bus tie cabinet between the two busbars; the dual power supply is a dual-circuit independent 10kV power supply, respectively drawn from different upstream 35kV substations, each with a capacity of 20MVA, and each is 100% standby; wherein, the load of busbar section I is the core production load of the sintering fan and the main exhaust fan, and the load of busbar section II is the standby sintering fan, dust removal fan and common load; during normal operation, the bus tie cabinet switch is in the open state, the two busbars operate independently, and the load is evenly distributed.

[0071] Preferably, the hot-rolled 110kV / 35kV system described in step S1, which is divided into finishing mill, roughing mill, and feeder functional zones for busbar networking, includes: a composite mode of 110kV single busbar segmentation and 35kV functional zone networking; the 110kV system is equipped with dual-circuit independent power supplies, respectively drawn from different busbars of the upstream 220kV substation, each with a capacity of 50MVA, serving as backups for each other; the 110kV busbar segmentation switch uses a ZF28-126GIS high-voltage switchgear; the 35kV... The kV system is divided into three independent busbar sections: "finishing mill / roughing mill / feeder". Each busbar section uses a KYN28A-12 centrally mounted high-voltage switchgear for networking. The load on the finishing mill section busbar is the finishing mill and finishing mill cooling pump set. The load on the roughing mill section busbar is the roughing mill and roughing mill main drive. The load on the feeder section busbar is the coiler, conveyor rollers and common loads. Each busbar section is equipped with a KYN28A-12 type bus tie switch. During normal operation, the switches of each bus tie switch are open, and each busbar section operates independently to avoid load interference.

[0072] Preferably, the bus tie cabinets mentioned in step S1 are all equipped with electric operating mechanisms, mechanical interlocking devices, and electrical interlocking devices, supporting both remote and local operation control; among them, the bus tie cabinets of the sintering 10kV system have a rated voltage of 12kV, a rated current of 2500A, and a short-circuit breaking current of 31.5kA; the bus tie cabinets of the hot-rolled 35kV system have a rated voltage of 35kV, a rated current of 3150A, and a short-circuit breaking current of 31.5kA; all bus tie cabinets adopt the top-in, top-out wiring method, which matches the size of the corresponding high-voltage cabinet and can be directly installed in parallel.

[0073] Preferably, the specific implementation steps of the power layer dual-power automatic switching protection in step S2 are as follows:

[0074] Automatic switching devices (ATS) of corresponding specifications are configured for the 10kV dual power supply for sintering and the 110kV dual power supply for hot rolling. The ATS is used to monitor the three-phase voltage, frequency and phase of the dual power supply in real time, and the monitoring accuracy meets the requirements of voltage ±0.5% and frequency ±0.1Hz.

[0075] The switching logic between the main power supply and the backup power supply is set as follows: when the main power supply is working normally, the backup power supply is in standby mode and the bus tie switch remains open; when the main power supply experiences a voltage loss (three-phase voltage ≤ 70% of rated voltage), undervoltage (three-phase voltage ≤ 80% of rated voltage), overvoltage (three-phase voltage ≥ 120% of rated voltage), phase loss, or frequency abnormality (≤ 48Hz or ≥ 52Hz) fault, and the fault duration is ≥ 0.5s, the ATS immediately issues a trip command to disconnect the main power supply switch;

[0076] After the automatic switching system (ATS) issues a trip command, it issues a closing command after a 20ms delay, closing the backup power switch and completing the seamless switching between the two power sources. The total switching time is ≤100ms. At the same time, the ATS is equipped with a dual interlocking mechanism of mechanical and electrical interlocks to prevent the main power source and backup power source from closing at the same time and to avoid power supply conflicts. When there is a fault in the backup power source, the switching function is automatically blocked to prevent the fault from escalating.

[0077] Preferably, the specific implementation steps of the busbar layer bus tie cabinet interlocking protection in step S2 are as follows:

[0078] Each bus tie cabinet of each section and zone busbar is equipped with a bus tie cabinet interlocking protection device. The device monitors the voltage, incoming current and bus tie switch status of the corresponding busbar in real time, with monitoring accuracy meeting the requirements of voltage ±0.5% and current ±1%.

[0079] Interlocking protection logic is set: when a short circuit (current ≥ 8 times the rated current), undervoltage or overcurrent fault occurs in a certain section or zone bus, and the fault duration is ≥ 0.3s, the interlocking protection device immediately issues a trip command to disconnect the incoming switch of the fault section;

[0080] After disconnecting the incoming switch of the faulty section, a closing command is issued after a 10ms delay, closing the corresponding bus tie switch and transferring the load of the faulty section to the normally operating bus, thus achieving fault isolation. The total protection action time is ≤150ms. Among them, the bus interlocking priority of the hot rolling 35kV system is set as finishing rolling section > roughing rolling section > feeder section, and the bus interlocking priority of the sintering 10kV system is set as section I bus > section II bus, giving priority to ensuring power supply to the core production load. The bus tie switch interlocking protection device adopts a dual-CPU redundant design. When the main CPU fails, the backup CPU automatically starts operation, with no protection blind spot, and has a fault memory function, recording the fault time, fault type and action parameters, which is convenient for fault review and analysis.

[0081] Preferably, the specific implementation steps of the load layer microcomputer integrated protection trip protection in step S2 are as follows:

[0082] Each high-pressure load in the sintering and hot rolling system (including sintering blowers, main exhaust fans, rolling mills, pump sets, etc.) is equipped with a separate microcomputer integrated protection device. Each device integrates overcurrent protection, instantaneous overcurrent protection, overvoltage protection, undervoltage protection, phase loss protection, grounding protection and overheat protection functions. The protection parameters can be set remotely through the background monitoring system or manually on site.

[0083] Set the protection operation parameters as follows: Overcurrent protection operating current is 1.2-1.5 times the rated load current, with an operating delay of 0.5-2s; Instantaneous overcurrent protection operating current is 5-8 times the rated load current, with instantaneous operation; Overvoltage protection operating voltage is 1.2 times the rated voltage, with an operating delay of 1s; Undervoltage protection operating voltage is 0.7 times the rated voltage, with an operating delay of 0.5s; Ground fault protection operating current is ≥100mA, with instantaneous operation.

[0084] When any of the above-mentioned faults occurs on the load side, the microcomputer-based integrated protection device immediately issues a trip command to disconnect the corresponding load switch, accurately isolate the faulty load, and prevent the fault from spreading to the bus and other loads. After the fault is cleared, the load power supply can be restored by remote reset through the background monitoring system or manual reset on site. The microcomputer-based integrated protection device is powered by dual power supplies of DC 220V and AC 100V. When either power supply fails, the device can still work normally and supports dual Ethernet communication to ensure that the fault signal is uploaded to the background monitoring system in real time.

[0085] The system is equipped with dedicated protection modules for high-power loads, including: dedicated reactive power compensation modules and high-voltage soft-start protection modules specifically designed for the impact load characteristics of high-power sintering fans and high-power hot rolling mills. These modules enable dynamic reactive power compensation for high-power loads, suppression of starting inrush current, and overload fault protection.

[0086] Preferably, the configuration of the high-power load dedicated protection module in step S3 includes:

[0087] A dedicated reactive power compensation module is configured, including: a Dynamic Var Compensator (SVG) as the reactive power compensation module. For a single 2500kW sintering blower in the sintering system, a 10kV, 800kvar SVG is configured; for a single 3500kW finishing mill in the hot rolling system, a 35kV, 1200kvar SVG is configured; and for a single 5000kW roughing mill in the hot rolling system, a 35kV, 1800kvar SVG is configured. The SVG has a response time ≤20ms, a compensation range from 0 to the corresponding rated capacity, and monitors the load-side power factor and bus voltage in real time. When the power factor <0.95 or the bus voltage fluctuation exceeds the allowable range, it automatically outputs reactive power to achieve dynamic compensation. The SVG integrates overcurrent, overvoltage, and overheat protection functions, automatically shutting down in case of a fault without affecting the normal operation of the main circuit. It adopts a cabinet structure with dimensions consistent with the KYN28A-12 centrally mounted high-voltage switchgear, allowing for direct parallel installation.

[0088] A dedicated soft-start protection module is configured, including: a high-voltage solid-state soft starter as the soft-start protection module; for 1800-3000kW high-power fans in sintering systems, a 10kV soft starter is configured with a rated current of 180-300A, a starting current multiple controlled at 2-2.5 times the rated current, an adjustable starting time of 10-20s, and an adjustable soft stop time of 5-10s; it features three starting modes: jump start, ramp start, and current-limiting start, adapting to the heavy-load starting characteristics of fans; for 3500-5000kW rolling mills in hot rolling systems, a 35kV soft starter is configured. The V-type soft starter has a rated current of 150-220A, a starting current multiple controlled at 2-2.5 times the rated current, an adjustable starting time of 15-25s, and an adjustable soft stop time of 8-15s. It features heavy-load starting and impact suppression functions. The soft starter integrates overcurrent, overvoltage, undervoltage, phase loss, grounding, overheating, and motor overload protection functions. It is linked with the load layer microcomputer integrated protection device to form dual protection. It adopts a cabinet structure and can be installed in parallel with the KYN28A-12 medium-voltage switchgear. It adopts a top-in, top-out wiring method, which is simple to wire and convenient to maintain.

[0089] Preferably, the establishment of the real-time linkage mechanism for background monitoring faults in step S4 includes:

[0090] Hardware configuration includes: an industrial-grade server (CPU i7, 16G memory, 1T hard drive) for the background monitoring system, equipped with dual monitors and audible and visual alarms; and an intelligent communication gateway configured on-site, supporting ModbusTCP and IEC61850 communication protocols, used to collect operating data and fault signals from high-voltage switchgear, dual-power automatic switching devices, bus tie interlock protection devices, microcomputer integrated protection devices, SVG reactive power compensation modules, and high-voltage solid-state soft starters.

[0091] Data acquisition and monitoring are carried out, including: the background monitoring system collects power supply voltage, current, frequency, bus voltage, current, high voltage switch status, operation status of each protection device, SVG compensation capacity, soft starter operating parameters, load power, temperature and other parameters in real time through the intelligent communication gateway. The data refresh cycle is ≤50ms, realizing real-time monitoring of the entire system's operating status.

[0092] The system implements coordinated fault handling, including: when a power supply layer fault, busbar layer fault, load layer fault, or protection module fault occurs in the system, the background monitoring system immediately receives the fault signal, automatically locates the fault location, identifies the fault type, controls the audible and visual alarms to issue alarm signals, and automatically generates a fault report, recording the fault time, fault parameters, and protection action status; at the same time, the system, based on the fault type, coordinates with the corresponding protection devices to complete fault isolation, load transfer, or equipment shutdown operations.

[0093] Remote operation and maintenance management includes: the back-end monitoring system supports remote login, parameter setting, switch operation and fault reset for operation and maintenance personnel. Operation and maintenance personnel can remotely monitor the system operation status and handle simple faults without on-site operation, thereby improving operation and maintenance efficiency and reducing the labor intensity of operation and maintenance.

[0094] like Figure 2 As shown, the second aspect of this embodiment is to provide a segmented networking and redundant protection system for a high-voltage power distribution system of hot rolling mill for steel sintering, for implementing the method of the first aspect, including:

[0095] The segmented differentiated networking module 101 is used to deploy segmented differentiated networks, including: for the 10kV power distribution system of the sintering main control building and the 110kV / 35kV switchgear power distribution system of the hot rolling workshop in the steel plant, differentiated segmented and zoned networking is carried out according to the load characteristics of different processes in sintering and hot rolling; the sintering 10kV system is divided into two independent busbars, and the hot rolling 110kV / 35kV system is networked according to the functional zones of finishing rolling, roughing rolling, and feeder; bus tie cabinets are configured between each segment and zone busbar, adapted to the structural characteristics of the KYN28A-12 medium-voltage switchgear, so as to realize the normal independent operation of each busbar and the interconnection and load transfer in case of failure;

[0096] The three-level redundancy protection system construction module 102 is used to construct a three-level redundancy protection system, including: building a three-level hierarchical redundancy protection architecture of power supply layer dual power supply automatic switching protection, busbar layer bus tie cabinet interlocking protection and load layer microcomputer integrated protection tripping protection. From top to bottom, it sequentially completes power supply side fault redundancy switching, busbar side fault interlocking isolation and load side fault precise tripping, forming a multi-level linkage protection closed loop.

[0097] The high-power load dedicated protection module configuration module 103 is used to configure the high-power load dedicated protection module, including: for the impact load characteristics of sintering high-power fans and hot rolling high-power mills, a dedicated reactive power compensation module and a high-voltage soft start protection module are respectively set up to realize high-power load reactive power dynamic compensation, starting inrush current suppression and overload fault protection.

[0098] The background monitoring fault real-time linkage mechanism construction module 104 is used to build a background monitoring fault real-time linkage mechanism, including: connecting the high-voltage cabinet, dual power supply switching device, bus tie interlock protection device, microcomputer integrated protection, reactive power compensation module and soft start protection module to the background monitoring system through the industrial Ethernet communication protocol, so as to realize the real-time acquisition of the operating parameters of all equipment, automatic fault location, protection action linkage alarm and remote operation and maintenance management.

[0099] To achieve the above objectives, this invention provides a segmented networking and redundant protection method for a high-voltage power distribution system in hot rolling mills for steel sintering. This method comprises four core components: segmented networking design, a three-level redundant protection system design, a dedicated protection module design for high-power loads, and a real-time linkage design for background monitoring. The specific technical solution is as follows:

[0100] 1. Segmented network design

[0101] The segmented network design is based on the differentiated load characteristics of the sintering and hot rolling processes, and is adapted to the network characteristics of medium-voltage switchgear such as KYN28A-12. It enables independent operation and interconnection of busbars, reduces the scope of fault impact, and improves load adaptability. It is divided into two parts: segmented network of the sintering 10kV system and zoned network of the hot rolling 110kV / 35kV system.

[0102] (1) Segmented networking of 10kV sintering system

[0103] The 10kV system of the sintering main control building adopts a single busbar segmented, dual-power supply mode, dividing the 10kV busbar into section I and section II. A bus tie cabinet (KYN28A-12 medium-voltage switchgear) is installed between the two sections to achieve independent operation and interconnection. Specific networking parameters include:

[0104] Power supply configuration: Dual-circuit independent 10kV power supply (Power Supply A and Power Supply B), respectively drawn from different 35kV substations above, each with a power capacity of 20MVA, and 100% backup for each other, meeting the power supply requirements of the entire sintering load.

[0105] Busbar sections: Section 10kVI busbar has sintering fans (1# and 2#, 2500kW each), main exhaust fan (1#, 3000kW), and dust removal fan (1800kW); Section 10kVII busbar has sintering fan (2500kW), dust removal fan (1800kW), and common loads (lighting and maintenance, total power 500kW); both busbar sections operate separately and the load is evenly distributed during normal operation, and the bus tie switch is disconnected.

[0106] Bus tie cabinet configuration: It adopts KYN28A-12 medium-voltage switchgear with rated voltage of 12kV, rated current of 2500A, short-circuit breaking current of 31.5kA, and is equipped with electric operating mechanism, mechanical interlocking device and electrical interlocking device. It supports remote / local operation and realizes interconnection and isolation between two bus sections.

[0107] Network compatibility: The KYN28A-12 high-voltage switchgear adopts a top-in, top-out wiring method. The switchgear is 800mm wide, 1500mm deep, and 2300mm high, which matches the size of the 10kV power distribution room in the sintering main control building. The busbars are connected with copper busbars, and the contact resistance is ≤50μΩ to ensure reliable network configuration.

[0108] (2) Hot-rolled 110kV / 35kV system zoned networking

[0109] The hot-rolled 110kV / 35kV system adopts a segmented 110kV single busbar network and a 35kV zoned network pattern of "finishing mill / roughing mill / feeder". The 110kV busbar is divided into Section I and Section II, and the 35kV busbar is divided into finishing mill section busbar, roughing mill section busbar, and feeder section busbar. Bus tie cabinets are set between each section of the busbar to achieve independent operation and interconnection. The specific networking parameters are as follows:

[0110] 110kV power supply configuration: Dual-circuit independent 110kV power supply, drawn from the upstream 220kV substation, with a power capacity of 50MVA each, serving as backup for each other. The 110kV busbar adopts a single busbar segmentation, and the segment switch adopts ZF28-126GIS high-voltage cabinet with a rated current of 3150A and a short-circuit breaking current of 40kA.

[0111] 35kV Zonal Network: The 35kV busbar is divided into a finishing mill section, a roughing mill section, and a feeder section, all using KYN28A-12 centrally mounted high-voltage switchgear. Finishing Mill Section Busbar: Equipped with finishing mills F1-F7 (single unit power 3500kW) and finishing mill cooling pump units (total power 2000kW). Load characteristics include low impact load and high precision requirements, with busbar voltage fluctuation ≤±2%. Roughing Mill Section Busbar: Equipped with roughing mills R1-R2 (single unit power 5000kW) and roughing mill main drive (power 4000kW). Load characteristics include high impact load and severe power fluctuation, with busbar voltage fluctuation ≤±5%. Feeder Section Busbar: Equipped with a coiler, conveyor rollers, and common loads (total power 3000kW). Load characteristics include distributed load and relatively small fluctuations.

[0112] Bus tie configuration: KYN28A-12 bus tie cabinets are installed between the finishing rolling section and the roughing rolling section, and between the roughing rolling section and the feeder section. The rated current is 3150A, the short-circuit breaking current is 31.5kA, and the interlock protection device is configured. During normal operation, the sectional switches are open and each bus section operates independently; in case of a fault, the interlock is closed to realize load transfer.

[0113] Network compatibility: The hot-rolled 35kV distribution room adopts a double-row layout, with KYN28A-12 high-voltage cabinets arranged symmetrically. The distance between cabinets is ≥1000mm to meet the space requirements for operation and maintenance. The busbars are connected by enclosed busbar bridges with an IP54 protection level to prevent dust and moisture from affecting the reliability of the network.

[0114] 2. Three-level redundancy protection system design

[0115] The three-level redundant protection system adopts an architecture of "automatic switching of dual power sources at the power supply level + interlocking protection of bus tie cabinets at the busbar level + microcomputer-based integrated protection tripping at the load level". The three layers of protection cooperate with each other and are redundant to each other, realizing multi-level isolation and rapid handling of faults from the power supply side to the load side. The protection action time is ≤200ms, which greatly improves the reliability of power supply.

[0116] (1) Dual power supply automatic switching protection at the power layer

[0117] For the power supply layer protection, targeting the 10kV dual power supply for sintering and the 110kV dual power supply for hot rolling, an automatic power switching system (ATS) is configured to enable rapid and automatic switching of the backup power supply in the event of a main power supply failure, with a switching time of ≤100ms and no manual intervention. Specific design features include:

[0118] Monitoring parameters: Real-time monitoring of the three-phase voltage, frequency, and phase of the dual power supply; monitoring accuracy: voltage ±0.5%, frequency ±0.1Hz.

[0119] Switching logic: When the main power supply (power supply A / 110kV I section) is normal, the backup power supply (power supply B / 110kV VII section) is on standby, and the bus tie switch is disconnected; when the main power supply experiences a voltage loss (three-phase voltage ≤70% of rated voltage), undervoltage (≤80% of rated voltage), overvoltage (≥120% of rated voltage), phase loss, or frequency abnormality (≤48Hz or ≥52Hz) fault, lasting for ≥0.5s, it is determined to be a fault, the main power supply switch is immediately tripped, and the backup power supply switch is closed after a 20ms delay, achieving seamless switching.

[0120] Interlocking mechanism: Equipped with mechanical interlocking and electrical interlocking to prevent the simultaneous closing of dual power switches and avoid power supply conflicts; when the backup power supply fails, the switching function is interlocked to prevent the fault from escalating.

[0121] Compatible parameters: The sintering 10kV dual power supply switching device has a rated voltage of 10kV and a rated current of 2500A; the hot rolling 110kV dual power supply switching device has a rated voltage of 110kV and a rated current of 3150A, both of which are compatible with the on-site power supply parameters.

[0122] (2) Interlocking protection of busbar layer bus tie cabinet

[0123] Busbar layer protection is designed for sintered 10kV bus tie cabinets and hot-rolled 35kV bus tie cabinets in various sections. Interlocking protection devices are configured to enable rapid tripping of the incoming line switch and closing of the bus tie switch in the event of a busbar fault, transferring the load of the faulty section to the normal busbar section and isolating the fault. The protection action time is ≤150ms. Specific design includes:

[0124] Monitoring parameters: Real-time monitoring of bus voltage, incoming current, and bus tie switch status for each section. Monitoring accuracy: voltage ±0.5%, current ±1%.

[0125] Interlocking logic: During normal operation, the bus tie switch is open, and each bus section operates independently; when a short circuit (current ≥ 8 times the rated current), undervoltage, or overcurrent fault occurs in a certain bus section, and the duration is ≥ 0.3s, the incoming switch of the faulty section is immediately tripped, and the bus tie switch is closed after a delay of 10ms, so that the load of the faulty section is carried by the normal section bus and the faulty bus is isolated.

[0126] Interlocking priority: Hot rolling 35kV busbar interlocking priority: finishing rolling section > roughing rolling section > feeder section, with priority given to ensuring power supply to precision equipment in the finishing rolling section; Sintering 10kV busbar interlocking priority: Section I (core fan) > Section II (standby fan), with priority given to ensuring power supply to the core sintering load.

[0127] Protection redundancy: The interlocking protection device of the bus tie cabinet adopts a dual-CPU redundancy design. When the main CPU fails, the backup CPU automatically starts, with no protection blind spot; it is equipped with a fault memory function to record the fault time, type and action parameters, which facilitates fault analysis.

[0128] (3) Load layer microcomputer integrated protection trip protection

[0129] The load layer protection is designed for all high-pressure loads in sintering and hot rolling processes (fans, mills, pump units, etc.). It is equipped with a microcomputer-based integrated protection device to achieve rapid tripping during load-side faults, isolate faulty loads, and prevent fault propagation to the busbar. The protection action time is ≤50ms. Specific design features include:

[0130] The protection configuration includes one microcomputer-based integrated protection device for each high-voltage load, which integrates overcurrent protection, instantaneous overcurrent protection, overvoltage protection, undervoltage protection, phase loss protection, grounding protection, and overheat protection functions. The protection parameters can be set remotely or locally.

[0131] The protection parameters include: overcurrent protection: operating current 1.2-1.5 times rated current, delay 0.5-2s; instantaneous overcurrent protection: operating current 5-8 times rated current, instantaneous operation; overvoltage protection: operating voltage 1.2 times rated voltage, delay 1s; undervoltage protection: operating voltage 0.7 times rated voltage, delay 0.5s; grounding protection: operating current ≥100mA, instantaneous operation.

[0132] The tripping logic includes: when a fault occurs on the load side, the microcomputer integrated protection device will immediately activate, trip the load switch, isolate the faulty load, and not affect the operation of the bus and other loads; after the fault is cleared, it can be remotely / locally reset to restore power supply.

[0133] The redundant design ensures that the microcomputer-based integrated protection device is powered by dual power supplies (DC 220V + AC 100V), so that the device can continue to operate normally in the event of a failure of either power supply; it is also configured with communication redundancy, supporting dual Ethernet communication to ensure that fault signals are uploaded in real time.

[0134] 3. Design of a dedicated protection module for high-power loads

[0135] For high-power loads such as sintering fans (power ≥ 1800kW) and hot rolling mills (power ≥ 3000kW), a dedicated reactive power compensation module and soft start protection module are configured to reduce starting inrush current, stabilize bus voltage, and improve power supply quality. The module is compatible with KYN28A-12 high-voltage switchgear for parallel installation without the need for additional cabinets.

[0136] (1) Reactive power compensation module design

[0137] The reactive power compensation module uses a dynamic reactive power compensation device (SVG) to compensate for the reactive power of high-power loads in real time, stabilize the bus voltage, and improve the power factor (≥0.95). Specific parameters include:

[0138] The reactive power compensation for the sintering fan is configured with an SVG capacity of 800kvar and a rated voltage of 10kV for each 2500kW sintering fan. The response time is ≤20ms and the compensation range is 0-800kvar. It compensates for reactive power fluctuations during the operation of the fan in real time, and the bus voltage fluctuation is ≤±2%.

[0139] The reactive power compensation for hot rolling mills is configured with an SVG capacity of 1200kvar for a single 3500kW finishing mill and an SVG capacity of 1800kvar for a single 5000kW roughing mill. The rated voltage is 35kV, the response time is ≤20ms, the compensation range is 0-1800kvar, and it suppresses voltage flicker caused by mill impact loads, with bus voltage fluctuations ≤±3%.

[0140] The control logic is that the SVG monitors the load-side power factor and bus voltage in real time. When the power factor is <0.95 or the bus voltage fluctuation exceeds the allowable range, it automatically outputs reactive power to achieve dynamic compensation. It has overcurrent, overvoltage and overheat protection functions, and automatically shuts down in case of failure without affecting the operation of the main circuit.

[0141] With installation adapters, the SVG module adopts a cabinet structure with the same dimensions as the KYN28A-12 high-voltage cabinet (800mm wide, 1500mm deep, and 2300mm high), and can be directly installed alongside the high-voltage cabinet, saving space in the power distribution room.

[0142] (2) Design of soft start protection module

[0143] The soft-start protection module uses a high-voltage solid-state soft starter to achieve smooth starting of high-power loads, reduce starting inrush current (≤2.5 times rated current), avoid sudden voltage drops on the bus, and protect the motor and the power grid. Specific parameters include:

[0144] Sintering fan soft start: 10kV, 1800-3000kW sintering fans are equipped with soft starters with rated voltage of 10kV, rated current of 180-300A, starting current multiple of 2-2.5 times, starting time adjustable from 10-20s, soft stop time adjustable from 5-10s, and three starting modes: jump start, ramp start, and current limiting start, which are suitable for the heavy load starting characteristics of the fans.

[0145] Hot rolling mill soft start: 35kV, 3500-5000kW rolling mills are equipped with soft starters with rated voltage of 35kV, rated current of 150-220A, starting current multiple of 2-2.5 times, starting time adjustable from 15-25s, soft stop time adjustable from 8-15s, and heavy load starting and impact suppression functions, which are suitable for the characteristics of frequent starting and large impact load of rolling mills.

[0146] Protection functions include: integrated overcurrent, overvoltage, undervoltage, phase loss, grounding, overheating, and motor overload protection. Protection parameters are linked with the load layer microcomputer integrated protection system. In case of a fault, the soft starter will act first, and if it fails, the microcomputer integrated protection system will trip, providing dual protection and improving reliability.

[0147] With installation adapters, the soft starter cabinet size is consistent with the KYN28A-12 high-voltage cabinet, allowing for parallel installation. It adopts a top-in, top-out wiring method, directly connecting to the high-voltage cabinet busbar, simplifying wiring and facilitating maintenance.

[0148] 4. Real-time linkage design for background monitoring

[0149] The background monitoring system adopts industrial Ethernet + IoT communication technology to achieve real-time data interaction and fault linkage with high-voltage switchgear, dual power supply switching devices, bus tie interlock protection devices, microcomputer integrated protection devices, SVG modules, and soft start modules. The monitoring response time is ≤100ms. The specific design is as follows:

[0150] Hardware configuration: The background monitoring host adopts an industrial-grade server (CPU i7, memory 16G, hard disk 1T), equipped with dual monitors and audible and visual alarms; the site is equipped with an intelligent communication gateway (supporting ModbusTCP and IEC61850 protocols) to collect the operating data and fault signals of each device.

[0151] Monitoring content: Real-time monitoring of power supply voltage / current / frequency, bus voltage / current, high-voltage switch status, protection device operation status, SVG compensation capacity, soft start operation parameters, load power / temperature and other parameters, with a data refresh cycle of ≤50ms.

[0152] Fault Linkage Logic: Power Supply Layer Fault: After the dual power supply switching device activates, a fault signal is immediately uploaded. The background monitoring system displays the faulty power supply, switching time, and activation status in real time, triggers an audible and visual alarm, and automatically generates a fault report. Busbar Layer Fault: After the bus tie interlocking protection device activates, the faulty busbar, interlocking activation time, and load transfer status are uploaded. The background monitoring system automatically locates the faulty busbar, displays the fault current and voltage waveforms, and triggers an audible and visual alarm. Load Layer Fault: After the microcomputer integrated protection device trips, the faulty load, tripping time, and fault type are uploaded. The background monitoring system displays the location of the faulty load, fault parameters, triggers an audible and visual alarm, automatically isolates the faulty load, and prompts maintenance personnel for handling.

[0153] Protection module failure: When the SVG or soft start module fails, the fault signal is uploaded, the background monitoring system displays the fault module and fault type, sounds and lights an alarm, and automatically switches to the backup module or exits operation.

[0154] Remote operation and maintenance: Supports remote login, parameter setting, switch operation, and fault reset. Operation and maintenance personnel can remotely monitor the system operation status and handle simple faults without on-site operation, thus improving operation and maintenance efficiency.

[0155] The technical solution of the present invention will be described in detail below with reference to two specific embodiments (Application 1: 10kV power distribution system for sintering in a large steel plant; Application 2: 110kV / 35kV power distribution system for hot rolling in a large steel plant). All parameters in the embodiments are actual engineering application parameters and can be directly implemented.

[0156] Application Example 1: Segmented Networking and Redundancy Protection of a 10kV Sintering Power Distribution System in a Large Steel Plant

[0157] The 10kV power distribution system of the sintering main control building of a large steel plant originally operated on a single busbar with no segmentation and a single power supply. It supplied power to two sintering fans (2500kW / unit), one main exhaust fan (3000kW), two dust removal fans (1800kW / unit), and a common load of 500kW, for a total load of 12100kW. The original system experienced frequent single-power-supply failures, resulting in 3-5 power outages per year, with each outage causing losses of ≥2 million RMB. The fans suffered from high starting inrush currents (6-7 times the rated current), large busbar voltage fluctuations (±8%), and frequent false trips of protection devices. Furthermore, the lack of dedicated reactive power compensation and soft-start devices resulted in short motor lifespans and high maintenance costs. After the system was upgraded using the technical solution of this invention, its operation became stable and the improvement was significant.

[0158] Segmented network implementation includes

[0159] (1) Power supply configuration: A new 10kV backup power supply is added, which is drawn from the No. 2 bus of the 35kV substation above. Together with the original power supply (drawn from the No. 1 bus), it forms a dual-circuit independent power supply with a capacity of 20MVA. They are 100% backup for each other and meet the power supply requirements of all loads.

[0160] (2) Busbar segmentation: The original 10kV single busbar is transformed into a double busbar of Section I and Section II, using KYN28A-12 medium-voltage switchgear for networking. The switchgear is 800mm wide, 1500mm deep and 2300mm high, with top-in and top-out wiring. Section I busbar carries No. 1 sintering fan (2500kW), main exhaust fan (3000kW) and No. 1 dust removal fan (1800kW), with a total load of 7300kW. Section II busbar carries No. 2 sintering fan (2500kW), No. 2 dust removal fan (1800kW) and common load (500kW), with a total load of 4800kW. When both busbars are in normal operation, the sectional switches are disconnected and the load is evenly distributed.

[0161] (3) Bus tie cabinet configuration: One KYN28A-12 bus tie cabinet is installed between the two bus sections, with a rated voltage of 12kV, a rated current of 2500A, a short circuit breaking current of 31.5kA, and is equipped with an electric operating mechanism and a mechanical + electrical interlocking device. It supports remote / local operation and realizes interconnection and isolation between the two bus sections.

[0162] The implementation of a three-level redundancy protection system includes:

[0163] (1) Dual power supply automatic switching protection: Configure one set of 10kV dual power supply automatic switching device (ATS) with a rated current of 2500A to monitor the three-phase voltage, frequency and phase of the dual power supply in real time; Switching logic: If the main power supply (I-stage power supply) loses voltage (≤70% of rated voltage), undervoltage, overvoltage, phase loss, or frequency abnormality for 0.5s, the main power supply switch will be immediately tripped, and the backup power supply (II-stage power supply) switch will be closed after a delay of 20ms, with a switching time of ≤100ms; Configure mechanical + electrical interlock to prevent the dual power supply from running in parallel and to lock the switching function in case of fault.

[0164] (2) Interlocking protection of bus tie cabinet at bus level: The bus tie cabinet is equipped with one set of interlocking protection device to monitor the voltage, incoming current and status of bus tie switch of the two bus sections in real time; Interlocking logic: If a bus section is short-circuited (≥8 times the rated current), undervoltage, or overcurrent for 0.3s, the incoming switch of the faulty section will be immediately tripped, and the bus tie switch will be closed after a delay of 10ms, and the load will be transferred to the normal section of the bus; Interlocking priority: Section I (core fan) > Section II, giving priority to ensuring the power supply of the core load; The device has dual CPU redundancy, fault memory function, and protection action time ≤150ms.

[0165] (3) Load layer microcomputer integrated protection trip protection: Each high-voltage load (fan, pump group) is equipped with a microcomputer integrated protection device, which integrates overcurrent, instantaneous trip, overvoltage, undervoltage, phase loss, grounding and overheat protection; protection parameters: overcurrent 1.3 times rated current, delay 1s, instantaneous trip 6 times rated current, instantaneous action, overvoltage 1.2 times, undervoltage 0.7 times, delay 0.5s, grounding ≥100mA, instantaneous action; instantaneous trip in case of fault (≤50ms), isolate faulty load, dual power supply, dual Ethernet communication, redundant and reliable.

[0166] The implementation of the high-power load dedicated protection module includes:

[0167] (1) Reactive power compensation module: Each 2500kW sintering blower is equipped with a 10kV, 800kvar SVG dynamic reactive power compensation device with a response time ≤20ms and a compensation range of 0-800kvar; real-time monitoring of power factor and bus voltage; automatic compensation when power factor <0.95 or voltage fluctuation exceeds ±2%; equipped with overcurrent, overvoltage and overheat protection; cabinet structure and installed in parallel with KYN28A-12 cabinet.

[0168] (2) Soft start protection module: Each 1800-3000kW wind turbine is equipped with a 10kV high-voltage solid-state soft starter with a rated current of 180-300A, a starting current of 2.2 times the rated current, a starting time of 15s, and a soft stop time of 8s; it has a sudden jump / ramp / current limiting start mode, and integrates overcurrent, overvoltage, phase loss, overheat, and motor overload protection, with dual protection linked with microcomputer integrated protection; the cabinet is installed in parallel with KYN28A-12, with top-in and top-out wiring.

[0169] Real-time backend monitoring and linkage implementation includes:

[0170] Configured with a background monitoring system, including an industrial server, dual monitors, audible and visual alarms, and a field intelligent communication gateway (Modbus TCP protocol); real-time monitoring of the operating parameters and status of power supplies, busbars, high-voltage cabinets, protection devices, SVG, and soft starters, with a data refresh cycle of 50ms; fault linkage: automatic switching, alarm, and report generation for power supply faults; automatic location, load transfer, and alarm for busbar faults; automatic tripping, isolation, and alarm for load faults; remote login, parameter setting, switch operation, and fault reset, ensuring efficient operation and maintenance.

[0171] The system has been running for 6 months after the upgrade, and the results are remarkable:

[0172] Power supply reliability: Dual power supply switching is normal, there are no power outages due to power failures, bus fault isolation is rapid, the average annual power outage time is ≤3 minutes, no system-wide shutdown accidents have occurred, and economic losses of ≥12 million yuan have been avoided.

[0173] Load adaptability: The busbars operate independently in sections, reducing the scope of fault impact by 75%, ensuring stable power supply to the core fans, and preventing false tripping of protection circuit breakers.

[0174] Power quality: SVG dynamic compensation, power factor stable ≥0.96, bus voltage fluctuation ≤±1.8%; soft starter starting inrush current ≤2.3 times rated current, no voltage drop, stable motor operation, maintenance cost reduced by 40%, motor life extended by 35%.

[0175] Operation and maintenance efficiency: Real-time backend linkage, fault location and handling time ≤ 4 minutes, convenient remote operation and maintenance, operation and maintenance efficiency improved by 85%, and labor costs reduced.

[0176] Application Example 2: Segmented Networking and Redundant Protection of 110kV / 35kV Power Distribution System for Hot Rolling Mill in a Large Steel Plant

[0177] A large steel plant's 1780mm hot rolling production line has a 110kV / 35kV power distribution system. The original system had a single, unsegmented 110kV busbar and a general 35kV network. The 35kV system connected finishing mills F1-F7 (3500kW / unit), roughing mills R1-R2 (5000kW / unit), coilers, roller conveyors, and utility loads, with a total load of 38500kW. The original system suffered from several problems: single-busbar faults were prone to propagation; the roughing mill's impact load interfered with the finishing mill's power supply, resulting in low product precision; the mills experienced large starting inrush currents (7-8 times the rated current), severe voltage flicker (±10%), and frequent protection system tripping errors; and the lack of dedicated reactive power compensation and soft-start devices led to a high mill failure rate and significant downtime losses. After adopting the technical solution of this invention, the system performance was significantly improved.

[0178] Segmented networking implementation includes:

[0179] (1) 110kV power supply configuration: dual-circuit independent 110kV power supply, drawn from different busbars of the upstream 220kV substation, with a power capacity of 50MVA for each and serving as backup for each other; the 110kV busbar adopts single busbar segmentation, with segment switch ZF28-126GIS high-voltage cabinet, rated current 3150A, short-circuit breaking current 40kA.

[0180] (2) 35kV zoned network: The 35kV busbar is divided into a fine rolling section, a rough rolling section, and a feeder section, all of which adopt KYN28A-12 medium-voltage switchgear for networking, arranged in double rows, with a distance of 1200mm between switchgears, and enclosed busbar bridge connection, with a protection level of IP54.

[0181] Finishing mill busbar: equipped with F1-F7 finishing mills (3500kW×7=24500kW) and finishing mill cooling pump group (2000kW), with a total load of 26500kW. The load characteristics are stable and the precision requirements are high.

[0182] Roughing section busbar: equipped with R1-R2 roughing mill (5000kW×2=10000kW) and roughing main drive (4000kW), with a total load of 14000kW. The load characteristics are characterized by large impact and violent fluctuations.

[0183] Feeder section busbar: with winder, roller conveyor, common load (3000kW), total load 3000kW, load is distributed and fluctuates little.

[0184] (3) Bus tie cabinet configuration: One KYN28A-12 bus tie cabinet is installed between the finishing rolling section and the roughing rolling section, and between the roughing rolling section and the feeder section. The rated current is 3150A, the short circuit breaking current is 31.5kA, and the mechanical + electrical interlocking device is used for remote / local operation. During normal operation, the sectional switches are disconnected and each section operates independently.

[0185] The implementation of a three-level redundancy protection system includes:

[0186] (1) Dual power supply automatic switching protection: 110kV dual power supply is equipped with ATS device with rated current of 3150A to monitor voltage, frequency and phase; if the main power supply fails (undervoltage, undervoltage, overvoltage, phase loss, frequency abnormality) for 0.5s, the main power supply will be disconnected and the backup power supply will be closed, with a switching time of ≤100ms; mechanical + electrical interlocking is used to prevent parallel operation and fault blocking.

[0187] (2) Interlocking protection of bus tie cabinets at the bus level: Each 35kV bus tie cabinet is equipped with an interlocking protection device to monitor the bus voltage, current and switch status; if a section of the bus is short-circuited, undervoltage, or overcurrent for 0.3s, the incoming line of the faulty section is opened and the bus tie switch is closed, and the load is transferred; Interlocking priority: fine rolling section > rough rolling section > feeder section, with priority given to protecting the precision equipment of the fine rolling section; Dual CPU redundancy, protection action time ≤150ms.

[0188] (3) Load layer microcomputer integrated protection trip protection: Each rolling mill and pump group is equipped with a microcomputer integrated protection device, which integrates a full set of protection functions; protection parameters: overcurrent 1.4 times rated current, delay 1.5s, instantaneous trip 7 times rated current, instantaneous action, overvoltage 1.2 times, undervoltage 0.7 times, delay 0.5s, grounding ≥100mA, instantaneous action; fault instantaneous trip (≤50ms), dual power supply, dual Ethernet redundancy.

[0189] The implementation of the high-power load dedicated protection module includes:

[0190] (1) Reactive power compensation module: Each 3500kW finishing mill is equipped with 35kV and 1200kvarSVG, and each 5000kW roughing mill is equipped with 35kV and 1800kvarSVG. The response time is ≤20ms. Real-time reactive power compensation, suppression of voltage flicker, bus voltage fluctuation ≤±2.5%, power factor ≥0.95; cabinet structure and parallel installation with KYN28A-12.

[0191] (2) Soft start protection module: Each 3500-5000kW rolling mill is equipped with a 35kV high-voltage solid-state soft starter with a rated current of 150-220A, a starting current of 2.3 times the rated current, a starting time of 20s, and a soft stop time of 12s; heavy load start and impact suppression functions, integrated full set of protection, and dual protection with microcomputer integrated protection linkage; cabinet installation in parallel, with top-in and top-out wiring.

[0192] Real-time linkage implementation of background monitoring includes

[0193] The background monitoring system is configured the same as in Application Example 1, consisting of an industrial server, dual monitors, an audible and visual alarm, and an intelligent communication gateway (IEC61850 protocol); it monitors 110kV / 35kV power supply, busbars, high-voltage cabinets, protection devices, SVG, and soft-start parameters in real time, with a data refresh cycle of 50ms; fault linkage includes power switching, busbar load transfer, load tripping isolation, automatic alarm, and report generation; remote operation and maintenance includes parameter setting, switch operation, and fault reset.

[0194] The system has been running for 8 months after the upgrade, and the results are remarkable:

[0195] Power supply reliability: 110kV dual power supply switching is normal, 35kV bus faults are quickly isolated, there are no system-wide shutdown accidents, the average annual power outage time is ≤2 minutes, and economic losses of ≥20 million yuan are avoided.

[0196] Load adaptability: 35kV zoned grid, roughing rolling impact load does not interfere with finishing rolling, product accuracy is improved by 20%, defect rate is reduced by 15%, and economic benefits are significant.

[0197] Power quality: SVG dynamic compensation, power factor ≥0.96, bus voltage fluctuation ≤±2.2%; soft starter starting inrush current ≤2.4 times rated current, no voltage flicker, stable mill operation, 50% reduction in failure rate, and 45% reduction in maintenance cost.

[0198] Operation and maintenance efficiency: Real-time backend linkage, fault handling time ≤3 minutes, convenient remote operation and maintenance, operation and maintenance efficiency improved by 90%, and labor costs reduced.

[0199] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A segmented networking and redundant protection method for a high-voltage power distribution system in a hot-rolled sintered steel industry, characterized in that, include: S1, deploying segmented and differentiated network, including: for the 10kV power distribution system of the sintering main control building and the 110kV / 35kV switchgear power distribution system of the hot rolling workshop, differentiated segmented and zoned network is carried out according to the load characteristics of different processes in sintering and hot rolling; the sintering 10kV system is divided into two independent busbars, and the hot rolling 110kV / 35kV system is networked according to the functional zones of finishing rolling, roughing rolling, and feeder; bus tie cabinets are configured between each segment and zone busbar, adapted to the structural characteristics of KYN28A-12 medium-voltage switchgear, to achieve normal independent operation of each busbar and interconnection and load transfer in case of fault; S2, construct a three-level redundant protection system, including: building a three-level redundant protection architecture of power supply layer dual power supply automatic switching protection, busbar layer bus tie cabinet interlocking protection and load layer microcomputer integrated protection trip protection. From top to bottom, it completes power supply side fault redundancy switching, busbar side fault interlocking isolation and load side fault accurate tripping in sequence, forming a multi-level linkage protection closed loop. S3 is equipped with a dedicated protection module for high-power loads, including: a dedicated reactive power compensation module and a high-voltage soft start protection module respectively set up for the impact load characteristics of high-power sintering fans and high-power hot rolling mills, which are used to realize dynamic reactive power compensation for high-power loads, suppression of starting inrush current and overload fault protection. S4 establishes a real-time fault linkage mechanism for background monitoring, including: connecting high-voltage cabinets, dual-power switching devices, bus tie interlocking protection devices, microcomputer integrated protection, reactive power compensation modules and soft-start protection modules to the background monitoring system through industrial Ethernet communication protocol, so as to realize real-time acquisition of all equipment operating parameters, automatic fault location, protection action linkage alarm and remote operation and maintenance management.

2. The segmented networking and redundant protection method for a high-voltage power distribution system of hot-rolled steel sintering as described in claim 1, characterized in that, Step S1, which involves dividing the sintering 10kV system into two independent busbars, includes: adopting a single busbar segmentation and dual power supply mode, dividing the 10kV busbar into busbar section I and busbar section II, with a KYN28A-12 medium-voltage switchgear serving as the bus tie cabinet between the two busbars; the dual power supply consists of two independent 10kV power supplies, each drawn from different upstream 35kV substations, with each power supply having a capacity of 20MVA and being 100% standby for each other; wherein, the load of busbar section I is the core production load of the sintering blower and main exhaust fan, and the load of busbar section II is the standby sintering blower, dust removal fan, and common load; during normal operation, the bus tie cabinet switch is in the open state, the two busbars operate independently, and the load is evenly distributed.

3. The segmented networking and redundant protection method for a high-voltage power distribution system of hot-rolled steel sintering as described in claim 2, characterized in that, The hot-rolled 110kV / 35kV system described in step S1, which is organized into busbar networks according to the functional zones of finishing mill, roughing mill, and feeder, includes: a composite mode of 110kV single busbar segmentation and 35kV functional zone networking; the 110kV system is equipped with dual-circuit independent power supplies, respectively drawn from different busbars of the upstream 220kV substation, each with a capacity of 50MVA, serving as backups for each other; the 110kV busbar segmentation switches use ZF28-126GIS high-voltage switchgear; the 35kV... The system is divided into three independent busbar sections: "finishing mill / roughing mill / feeder". Each busbar section uses a KYN28A-12 centrally mounted high-voltage switchgear for networking. The load of the finishing mill section busbar is the finishing mill and finishing mill cooling pump set, the load of the roughing mill section busbar is the roughing mill and roughing mill main drive, and the load of the feeder section busbar is the coiler, conveyor rollers and common loads. Each busbar section is equipped with a KYN28A-12 type bus tie cabinet. During normal operation, the switches of each bus tie cabinet are open, and each busbar section operates independently to avoid load interference.

4. The segmented networking and redundant protection method for a high-voltage power distribution system for hot-rolled steel sintering as described in claim 3, characterized in that, The bus tie cabinets mentioned in step S1 are all equipped with electric operating mechanisms, mechanical interlocking devices and electrical interlocking devices, supporting dual control of remote operation and local operation; all bus tie cabinets adopt the top-in and top-out wiring method, which matches the size of the corresponding high-voltage cabinet and can be directly installed in parallel.

5. The segmented networking and redundant protection method for a high-voltage power distribution system of hot-rolled steel sintering as described in claim 4, characterized in that, The specific implementation steps of the power layer dual power supply automatic switching protection in step S2 are as follows: Automatic switching devices (ATS) of corresponding specifications are configured for the 10kV dual power supply for sintering and the 110kV dual power supply for hot rolling. The ATS is used to monitor the three-phase voltage, frequency and phase of the dual power supply in real time. Configure the switching logic between the main power supply and the backup power supply, including: when the main power supply is working normally, the backup power supply is in standby mode and the bus tie switch remains open; When the main power supply experiences a fault such as loss of voltage, undervoltage, overvoltage, phase loss, or abnormal frequency, and the fault duration is ≥0.5s, the ATS immediately issues a trip command to disconnect the main power supply switch. After the automatic switching device (ATS) issues a trip command, it issues a closing command after a 20ms delay, closing the backup power switch and completing the seamless switching between the two power sources. The total switching time is ≤100ms. At the same time, the ATS is equipped with a dual interlocking mechanism of mechanical and electrical interlocks. When there is a fault in the backup power supply, the switching function is automatically blocked.

6. The segmented networking and redundant protection method for a high-voltage power distribution system of hot-rolled steel sintering as described in claim 5, characterized in that, The specific implementation steps of the busbar layer bus tie cabinet interlocking protection in step S2 are as follows: Each section and zone busbar is equipped with a busbar tie cabinet interlocking protection device, which monitors the voltage, incoming current and busbar tie switch status of the corresponding busbar in real time. Interlocking protection logic is set: when a short circuit, undervoltage, or overcurrent fault occurs in a certain section or zone bus, and the fault duration is ≥0.3s, the interlocking protection device immediately issues a trip command to disconnect the incoming switch of the fault section; After disconnecting the incoming switch of the faulty section, a closing command is issued after a 10ms delay, closing the corresponding bus tie switch and transferring the load of the faulty section to the normally operating bus, thus achieving fault isolation. The total protection action time is ≤150ms. Among them, the bus interlocking priority of the hot rolling 35kV system is set as finishing rolling section > roughing rolling section > feeder section, and the bus interlocking priority of the sintering 10kV system is set as section I bus > section II bus, giving priority to ensuring power supply to the core production load. The bus tie switch interlocking protection device adopts a dual-CPU redundant design. When the main CPU fails, the backup CPU automatically starts operation.

7. The segmented networking and redundant protection method for a high-voltage power distribution system of hot-rolled steel sintering as described in claim 6, characterized in that, The specific implementation steps of the load layer microcomputer integrated protection trip protection in step S2 are as follows: Each high-pressure load in the sintering and hot rolling system is equipped with a separate microcomputer integrated protection device. Each device integrates overcurrent protection, instantaneous overcurrent protection, overvoltage protection, undervoltage protection, phase loss protection, grounding protection and overheat protection functions. The protection parameters can be set remotely through the background monitoring system or manually on site. Set the protection operation parameters, including: overcurrent protection operating current of 1.2-1.5 times the rated load current, operating delay of 0.5-2s; instantaneous overcurrent protection operating current of 5-8 times the rated load current, instantaneous operation; overvoltage protection operating voltage of 1.2 times the rated voltage, operating delay of 1s; undervoltage protection operating voltage of 0.7 times the rated voltage, operating delay of 0.5s; grounding protection operating current ≥100mA, instantaneous operation. When any of the above-mentioned faults occur on the load side, the microcomputer integrated protection device immediately issues a trip command to disconnect the corresponding load switch; after the fault is cleared, the load power supply is restored through remote reset via the background monitoring system or manual reset on site; the microcomputer integrated protection device is powered by dual power supplies of DC 220V and AC 100V and supports dual Ethernet communication to ensure that fault signals are uploaded to the background monitoring system in real time. Configure dedicated protection modules for high-power loads, including: dedicated reactive power compensation modules and high-voltage soft-start protection modules for the impact load characteristics of high-power sintering fans and high-power hot rolling mills, respectively, to achieve dynamic reactive power compensation for high-power loads, suppression of starting inrush current, and overload fault protection.

8. The segmented networking and redundant protection method for a high-voltage power distribution system for hot-rolled steel sintering as described in claim 7, characterized in that, The configuration of the high-power load dedicated protection module in step S3 includes: A dedicated reactive power compensation module is configured, including: using a dynamic reactive power compensation device (SVG) as the reactive power compensation module. The SVG has a response time ≤20ms, a compensation range of 0 to the corresponding rated capacity, and monitors the load-side power factor and bus voltage in real time. When the power factor <0.95 or the bus voltage fluctuation exceeds the allowable range, it automatically outputs reactive power to achieve dynamic compensation. The SVG integrates overcurrent, overvoltage, and overheat protection functions. It automatically exits operation in case of failure without affecting the normal operation of the main circuit. It adopts a cabinet structure with dimensions consistent with the KYN28A-12 medium-voltage switchgear and can be directly installed in parallel. The soft start protection module is configured, including: using a high-voltage solid-state soft starter as the soft start protection module; the soft start protection module integrates overcurrent, overvoltage, undervoltage, phase loss, grounding, overheating and motor overload protection functions, and is linked with the load layer microcomputer integrated protection device to form dual protection, and adopts a cabinet structure with top-in and top-out wiring.

9. A segmented networking and redundant protection method for a high-voltage power distribution system for hot-rolled sintered steel as described in claim 8, characterized in that, The establishment of a real-time fault linkage mechanism for background monitoring mentioned in step S4 includes: Hardware configuration includes: an industrial-grade server for the background monitoring system, equipped with dual monitors and audible and visual alarms; and an intelligent communication gateway configured on-site, supporting ModbusTCP and IEC61850 communication protocols, for collecting operating data and fault signals from high-voltage switchgear, dual-power automatic switching devices, bus tie interlock protection devices, microcomputer integrated protection devices, SVG reactive power compensation modules, and high-voltage solid-state soft starters. Data acquisition and monitoring are carried out, including: the background monitoring system collects power supply voltage, current, frequency, bus voltage, current, high voltage switch status, operation status of each protection device, SVG compensation capacity, soft starter operating parameters, load power and temperature parameters in real time through the intelligent communication gateway. The system implements coordinated fault handling, including: when a power supply layer fault, busbar layer fault, load layer fault, or protection module fault occurs in the system, the background monitoring system immediately receives the fault signal, automatically locates the fault location, identifies the fault type, controls the audible and visual alarms to issue alarm signals, and automatically generates a fault report, recording the fault time, fault parameters, and protection action status; at the same time, the system, based on the fault type, coordinates with the corresponding protection devices to complete fault isolation, load transfer, or equipment shutdown operations. Remote operation and maintenance management includes: the back-end monitoring system supports remote login, parameter setting, switch operation, and fault reset for operation and maintenance personnel.

10. A segmented networking and redundant protection system for a high-voltage power distribution system of hot-rolled steel sintering, used to implement the method described in any one of claims 1-9, characterized in that, include: The segmented differentiated networking module (101) is used to deploy segmented differentiated networks, including: for the 10kV power distribution system of the sintering main control building and the 110kV / 35kV switchgear power distribution system of the hot rolling workshop, differentiated segmented and zoned networking is carried out according to the load characteristics of different processes of sintering and hot rolling; the sintering 10kV system is divided into two independent busbars, and the hot rolling 110kV / 35kV system is networked according to the functions of finishing rolling, roughing rolling and feeder. Bus tie cabinets are configured between each segment and zone busbar, which are adapted to the structural characteristics of KYN28A-12 medium-voltage switchgear, so as to realize the normal independent operation of each busbar and the interconnection and load transfer in case of fault; The three-level redundancy protection system construction module (102) is used to construct a three-level redundancy protection system, including: building a three-level hierarchical redundancy protection architecture of power supply layer dual power supply automatic switching protection, busbar layer bus tie cabinet interlocking protection and load layer microcomputer integrated protection tripping protection. From top to bottom, it completes power supply side fault redundancy switching, busbar side fault interlocking isolation and load side fault accurate tripping in sequence, forming a multi-level linkage protection closed loop. A high-power load dedicated protection module configuration module (103) is used to configure a high-power load dedicated protection module, including: for the impact load characteristics of sintering high-power fans and hot rolling high-power mills, a dedicated reactive power compensation module and a high-voltage soft start protection module are respectively set up to realize high-power load reactive power dynamic compensation, starting impact current suppression and overload fault protection; The background monitoring fault real-time linkage mechanism construction module (104) is used to build a background monitoring fault real-time linkage mechanism, including: connecting the high voltage cabinet, dual power supply switching device, bus tie interlock protection device, microcomputer integrated protection, reactive power compensation module and soft start protection module to the background monitoring system through the industrial Ethernet communication protocol, so as to realize the real-time acquisition of all equipment operating parameters, automatic fault location, protection action linkage alarm and remote operation and maintenance management.

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