Mine hoisting high-voltage frequency conversion cabinet with online backup power device

Abstract

The invention belongs to the technical field of mine hoist control, and particularly provides a mine hoisting high-voltage frequency conversion cabinet with on-line backup power devices, which mainly comprises N stages of in-use power devices, at least one stage of on-line backup power device and the like, and the at least one stage of on-line backup power device is electrified like the in-use power devices but is in no-load operation. Good quality is kept, and once some stages of the in-use power device break down or are powered off, one or more stages of the online backup power device are used for rapidly replacing the fault part of the in-use power device; when the mine hoisting high-voltage frequency conversion cabinet works, the faulted power device is withdrawn and maintained off line, and the faulted power device is used as a part of the online backup power device after being repaired to be qualified so as to recover online no-load operation and be recycled, so that the downtime of the mine hoisting high-voltage frequency conversion cabinet can be controlled due to reasons, and normal operation can be recovered within a short time (20 minutes); the production efficiency is improved, risks and potential safety hazards caused by reasons are reduced, and social and economic benefits are remarkable.

Description

Technical Field

[0001] The invention belongs to the technical field of mine hoist control, and specifically proposes a mine hoist high-voltage frequency conversion cabinet with an online backup power device. Background Art

[0002] Mine hoist is the throat equipment of underground mines. The main shaft hoist is related to the output of the mine, and the auxiliary shaft hoist is related to the life safety of people going up and down. The practical requirement is that the downtime during operation is as short as possible, usually not more than 20 minutes; because when the fault occurs, the crew members are trapped in the middle of the shaft. If they are detained for a long time, it may cause the crew members to be agitated, and the safety hazards increase with the length of the downtime; in recent years, four-quadrant high-voltage inverters have been widely used in mine hoists, and have made great progress in energy saving, improving operating performance and safety. The traditional four-quadrant high-voltage inverter is mainly composed of a rectifier transformer and 3*n power units, where n is the number of cascaded power units per phase, and can be adjusted according to the rated output voltage of the power unit and the lifting capacity. The voltage level of the electric motor is selected. The secondary winding of the rectifier transformer is equipped with 3*n sets of three-phase windings. The number of secondary windings of the rectifier transformer is large and an angle difference (phase shift) is required between each set of windings. The manufacturing process is complicated and the cost is high. The high-voltage cables connecting the secondary winding and the corresponding power unit are of different lengths, which need to be produced on the production site, which is labor-intensive and time-consuming. The power unit is a wearing part. The usual way is to keep some power units offline at the place of use and replace the faulty power unit to repair the fault. The problem is that the offline storage of the spare power unit may cause the characteristics of the spare power unit to deteriorate due to poor storage or environmental factors, and its performance cannot be guaranteed. Therefore, the downtime due to some reasons is often in an uncertain state.

[0003] It is a known practice to temporarily short-circuit or bypass the output of the faulty power unit, downgrade and reduce the speed of the operation. This not only reduces production, but also causes the unit to run with a fault, which may expand the scope of the fault. This is only one of the emergency improvement methods and is not recommended for frequent use.

[0004] Some other known practices, such as the published patents "Switch-type unit redundant high-voltage inverter and control method thereof" (CN101594060A) and "A high-voltage inverter with inverter unit having bypass function" (CN 218733938 U), etc., have a spare power unit in the inverter. When one power unit fails, the spare power unit replaces the failed power unit by switching the circuit. However, there are also shortcomings: although the spare power unit is placed in the high-voltage inverter, it is always in an unpowered state, and the performance of the power unit cannot be determined; the high-voltage inverter becomes complicated due to the switching circuit, and there may be safety hazards.

[0005] In traditional concepts, rectifier transformers are not considered to be vulnerable parts because they are expensive and relatively reliable, but they may be damaged. It usually takes several days or even longer to repair a rectifier transformer. If a replacement rectifier transformer cannot be found, production will have to be stopped during this period, and the loss will be very serious. For the main shaft hoist, the shutdown affects the output; for the auxiliary shaft hoist and well drilling hoist for transporting personnel, it not only affects the output but also affects personal safety; for the hoist for transporting furnace materials in the blast furnace, it also involves the safety of the entire blast furnace; in order to solve the wiring space of the power unit and reduce the complexity of the manufacturing of the phase-shifting rectifier transformer, the disclosed patent "A cascaded high-voltage inverter" (CN 210985920 U), using two or more rectifier transformers in the same high-voltage inverter can certainly solve such problems to a certain extent, but it requires deep downgrading and speed reduction; taking the use of two rectifier transformers as an example, the series-connected power units are divided into two groups, which are powered by two rectifier transformers respectively. If one rectifier transformer is out of operation for some reason, it is necessary to reduce the speed by about one-half for emergency operation. Long-term and drastically reduced speed operation will seriously affect production.

[0006] To sum up, in order to combine the characteristics of mine hoists, it is necessary to continue to develop four-quadrant high-voltage inverters dedicated to mine hoists. Summary of the invention

[0007] In order to overcome the disadvantage of uncertain repair time of traditional four-quadrant high-voltage frequency converters, the present invention proposes a mine hoisting high-voltage frequency converter cabinet with an online backup power device, so that it can drive hoisting motors of various voltage levels.

[0008] The present invention adopts the following technical solutions to achieve its invention purpose: A mine hoisting high-voltage frequency conversion cabinet with an online backup power device, wherein the mine hoisting high-voltage frequency conversion cabinet is provided with a power device; the power device comprises N levels of in-use power devices and at least one level of online backup power device; the outlet terminals A1, B1 and C1 of the first level of in-use power device are connected together to form a three-phase high-voltage power circuit. o The output neutral point Q0 of the output, the output ends of the power devices in use are connected in series in order of A2-A1, B2-B1 and C2-C1 through single-phase high-voltage cables, and the output ends A2, B2 and C2 of the power devices in use at the Nth level are connected to the three-phase input ends of the lifting motor respectively, providing the lifting motor with three-phase high-voltage power with adjustable frequency and voltage. o The outlet terminals A1, B1, C1 and A2, B2, C2 of the online backup power device are in an idle state; the input terminals of the online backup power device and the in-use power device are connected in sequence through three-phase high-voltage cables, and connected to the input terminal of the grid-side power 6kV or 10kV to obtain grid-side power for the mine hoisting high-voltage frequency conversion cabinet. i, so that the high-voltage grid-side power supply with a frequency of 50Hz and a voltage of 6kV or 10kV i After the mine hoisting high-voltage frequency conversion cabinet regulates the voltage and frequency, a three-phase high-voltage power electric with adjustable frequency and voltage is obtained at the hoisting motor end. o , driving the mine hoist to operate; the online backup power device is powered on like the in-use power device but runs at no load, maintaining a good state and characteristics. Once some levels of the in-use power device fail, in a power outage, one or several levels of the online backup power device are used to quickly replace the faulty parts of the in-use power device, so that the mine hoisting high-voltage frequency conversion cabinet can resume normal operation in the shortest time without downgrading or reducing the speed; then the faulty power device is withdrawn and repaired offline. After the faulty power device is repaired and qualified, it is used as part of the online backup power device to resume online no-load operation in time and continue to maintain good quality, and is used in a circular manner, ensuring that the downtime of the mine hoisting high-voltage frequency conversion cabinet due to some reason is controllable and quickly resumes normal operation.

[0009] The power device is a basic power component for modular and standardized design, packaging and interface of the main circuit of the four-quadrant high-voltage inverter; the power device has three four-quadrant power units and a power transformer; the power transformer has three sets of secondary windings, which are respectively connected to the input ends of the three four-quadrant power units through three-phase low-voltage cables to provide power for the four-quadrant power units; the output ends of the three four-quadrant power units are respectively: A1, A2, B1, B2, C1, C2; the frame member of the power device has four layers, the power transformer is placed on the bottom layer of the frame member, and the three four-quadrant power units are respectively fixed on the insulating parts and placed in the other three layers of the frame member in sequence; the bottom of the frame member is equipped with heavy-duty universal wheels with side brakes to facilitate the rapid movement and positioning of the power device; the mine hoisting high-voltage frequency conversion cabinet is provided with N cooling fans, and the N-level power devices in use are placed under the fans in sequence for cooling during operation.

[0010] For the power supply of the mine site network i 6kV or 10kV, the rated phase voltage of the primary winding of the power transformer is 6kV. i When the voltage is 6kV, the primary winding is connected in a triangle Δ manner. i When the voltage is 10kV, the primary winding is connected in a "star Y" manner, and the power transformer can always be connected to the grid-side power supply u iThe connection method of the secondary windings of the three sets of power transformers is "delta Δ" or "star Y", and no phase shift is required; the input / output rated voltage of the four-quadrant power unit is designed and selected according to three-phase AC600V / single-phase AC730V. Therefore, the input / output rated voltage of the power transformer is 6 (10) / 3*0.6kV, and the rated capacity is 1.4*P e / N optional, where: P e To increase the rated capacity of the motor, N is the number of the power devices in use, and selection is made according to the output rated voltage of the four-quadrant power unit and the voltage level of the motor, as shown in Table 1.

[0011] Table 1: Selection of the number N of power devices in use

[0012] The mine hoisting high-voltage frequency conversion cabinet, which is composed of N levels of in-use power devices and at least one level of online backup power devices, has the following benefits after deep modularization and standardized design: 1) Once some levels of in-use power devices fail and the power is cut off, they can be replaced by one or more levels of the power devices in the online backup power devices. The mine hoisting high-voltage frequency conversion cabinet can be repaired in a short and controllable time, and there is no need to downgrade or reduce the speed for emergency operation with the fault; the faulty power device is withdrawn and repaired offline. After the faulty power device is repaired and qualified, it can be restored to online no-load operation in time as part of the online backup power device and recycled; 2) The rated capacity of the rectifier transformer of the known four-quadrant high-voltage frequency converter is usually 1.6*P e The present invention divides a known rectifier transformer into N power transformers, the heat dissipation condition is improved, the transformer production process is simplified, and the total capacity is 1.4*P e Through design selection, the total cost of the power transformer will not increase; moreover, the power transformer can be customized in small batches; 3) the power device can be prefabricated or purchased in batches, including the power transformer, four-quadrant power unit, three-phase and single-phase high and low voltage cables, insulating parts, frame components, etc., modularized and assembly-lined, which is conducive to reducing production and management costs and error rates and improving labor productivity.

[0013] The present invention proposes a mine hoisting high-voltage frequency conversion cabinet with an online backup power device, which is mainly composed of N levels of in-use power devices, at least one level of online backup power device, etc. At least one level of online backup power device is powered on like the in-use power device but runs at no-load to maintain good quality. Once some levels of the in-use power devices fail, after a power outage, one or more levels of the online backup power device are used to quickly replace the failed power devices; the failed power devices are withdrawn and repaired offline, and after the failed power devices are returned and qualified, they are promptly restored to online no-load operation as part of the online backup power device and recycled, ensuring that the downtime of the mine hoisting high-voltage frequency conversion cabinet due to reasons is controllable, and normal operation is restored in a relatively short time (20 minutes), thereby improving production efficiency and reducing risks and safety hazards caused by reasons, with significant social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A principle block diagram of a mine hoisting high-voltage frequency conversion cabinet with an online backup power device; Figure 2 The principle block diagram of the power device of the present invention; Figure 3 A schematic diagram of the panel layout of the power device of the present invention; Figure 4 Schematic diagram of the panel layout of the mine hoisting high-voltage frequency conversion cabinet according to the present invention.

[0015] In the figure: 1. Power device, 1.1. Four-quadrant power unit, 1.2. Power transformer, 1.3.1, 1.3.2, 1.3.3, three-phase low-voltage cable, 1.4, Insulation, 1.5, Frame member, 1.6, Heavy-duty universal wheel with side brake, 2. In-use power device, 3. Online backup power device, 4. Three-phase high-voltage cable, 5. Single-phase high-voltage cable, 6. Mine hoisting high-voltage frequency conversion cabinet, 7. Fan, 8. Hoisting motor. DETAILED DESCRIPTION

[0016] The embodiments of the present invention are described with reference to the accompanying drawings: Figure 1 Combination Figure 2 and Figure 4 A mine hoisting high-voltage frequency conversion cabinet 6 with an online backup power device has a more in-depth modular and standardized design, packaging and interface for the main circuit of the four-quadrant high-voltage frequency converter. The basic power component after deep modularization is called a power device 1, which further improves the replaceability. The mine hoisting high-voltage frequency conversion cabinet 6 is mainly composed of N-level in-use power devices 2, at least one level of online backup power devices 3, a three-phase high-voltage cable 4 connected between the input ends of the power devices 1, and a single-phase high-voltage cable 5 connected between the output ends; the outlet terminals A1, B1 and C1 of the first-level in-use power device 2 are connected together to form a three-phase high-voltage power cable uo The output neutral point Q0, the output ends of the power device 2 in use are connected in series in order of A2-A1, B2-B1 and C2-C1 through the single-phase high-voltage cable 5, and the output ends A2, B2 and C2 of the power device 2 in use at the Nth level are connected to the three-phase input ends of the lifting motor 8 respectively, providing the lifting motor 8 with a three-phase high-voltage power u with adjustable frequency and voltage o ; The outlet terminals A1, B1, C1 and A2, B2, C2 of at least one level of online backup power device 3 are in an idle state; the input terminals of at least one level of online backup power device 3 and the in-use power device 2 are connected together in sequence through a three-phase high-voltage cable 4, and connected to the input terminal of the grid-side power 6kV or 10kV, so as to obtain the grid-side power u for the mine hoisting high-voltage frequency conversion cabinet i In this way, the high-voltage grid-side power supply with a frequency of 50Hz and a voltage of 6kV or 10kV i After the mine hoisting high-voltage frequency conversion cabinet 6 regulates the voltage and frequency, a three-phase high-voltage power electric power with adjustable frequency and voltage is obtained at the hoisting motor 8. o , driving the mine hoist to operate; except that, at least one level of online backup power device 3 is powered on like the in-use power device 2 but runs at no load, maintaining a good state and characteristics. Once some levels of the in-use power device 2 fail, in a power outage state, one or more levels of the power device 1 in the online backup power device 3 are used to quickly replace the faulty part of the in-use power device 2, and the mine hoisting high-voltage frequency conversion cabinet 6 can resume normal operation in the shortest time without downgrading or reducing the speed; the faulty power device 1 is withdrawn and repaired offline. After the faulty power device 1 is repaired and qualified, it is used as part of the online backup power device 3 to resume online no-load operation in time and continue to maintain good quality, and is used in a circular manner to ensure that the downtime of the mine hoisting high-voltage frequency conversion cabinet 6 due to some reason is controllable and resumes normal operation in a relatively short time (20 minutes).

[0017] Figure 2 Combination Figure 3 , Figure 4The power device 1 is mainly composed of three four-quadrant power units 1.1, a power transformer 1.2, three three-phase low-voltage cables 1.3.1, 1.3.2 and 1.3.3, an insulating member 1.4, a frame member 1.5, and a heavy-duty universal wheel 1.6 with a side brake. The power transformer 1.2 has three sets of secondary windings, which are respectively connected to the input ends of the three four-quadrant power units 1.1 through three-phase low-voltage cables 1.3.1, 1.3.2 and 1.3.3 to provide power for the four-quadrant power units 1.1; the output ends of the three four-quadrant power units 1.1 are respectively: A1 , A2, B1, B2, C1, C2; the power device 1 frame member has four layers, the power transformer 1.2 is placed on the bottom layer of the frame member, the three four-quadrant power units 1.1 are respectively fixed on the insulating member 1.4 and are placed in the other three layers of the frame member 1.5 in sequence; the bottom of the frame member 1.5 of the power device 1 is equipped with heavy-duty universal wheels 1.6 with side brakes to facilitate the rapid movement and positioning of the power device 1; the mine hoisting high-voltage frequency conversion cabinet 6 is provided with N cooling fans 7, and the N-level power devices 2 in use are placed under the fans 7 in sequence for cooling during operation.

[0018] Figure 1 and Figure 2 In the mine, the power grid side i 6kV or 10kV, the rated phase voltage of the primary winding of the power transformer 1.2 is 6kV. i When the voltage is 6kV, the primary winding is connected in a triangle Δ manner. i When the voltage is 10 kV, the primary winding is connected in a "star Y" manner, and the power transformer 1.2 can always be connected to the grid-side power supply u i The connection method of the secondary windings of the three sets of power transformers 1.2 is "delta Δ" or "star Y", and no phase shift is required; the input / output rated voltage of the four-quadrant power unit 1.1 is designed and selected according to three-phase AC600V / single-phase AC730V. Therefore, the input / output rated voltage of the power transformer 1.2 is 6 (10) / 3 * 0.6kV, and the rated capacity is (1.4 * P e / N) optional, where: P e To increase the rated capacity of the motor 8, N is the number of the power devices 1 in use, and selection is made according to the output rated voltage of the four-quadrant power unit 1.1 and the voltage level of the motor 8, as shown in Table 1.

[0019] Table 1: Selection of the number N of power devices 1 in use

[0020] Figure 1 and Figure 2 In the invention, the mine hoisting high-voltage frequency conversion cabinet 6 composed of N-level in-use power devices 2 and at least one-level online backup power device 3, which has been deeply modularized and standardized in design, has the following benefits: 1) For example, after the second-level fault of the in-use power device 2 occurs, the power is cut off, and it is replaced by the first-level power device 1 in the online backup power device 3. The mine hoisting high-voltage frequency conversion cabinet 6 can be repaired in a short time and is controllable, without downgrading and speed reduction for emergency operation with a defect; the faulty second-level power device 1 is withdrawn and repaired offline, and the faulty power device 1 is promptly restored to online no-load operation as the first-level online backup power device 3 after being repaired and qualified, and is recycled; 2) The rated capacity of the rectifier transformer of the known four-quadrant high-voltage frequency converter is usually 1.6*P e The present invention divides a known rectifier transformer into N power transformers 1.2, the heat dissipation condition is improved, the transformer production process is simplified, and the total capacity is 1.4*P e By design and selection, the total cost of the power transformer 1.2 will not increase; moreover, the power transformer 1.2 can be customized in small batches. For example, the power transformer 1.2 with a rated capacity of 220kVA built in the power device 1 can be used to drive a lifting motor 8 with a rated capacity of 800kW / 6kV (N=5) or 1250kW / 10kV (N=8); 3) The power device 1 can be prefabricated or purchased in batches, including the power transformer 1.2, a four-quadrant power unit 1.1, a three-phase high-voltage cable 4 and a single-phase high-voltage cable 5, three-phase low-voltage cables 1.3.1, 1.3.2 and 1.3.3, an insulating part 1.4, a frame member 1.5 and a heavy-duty universal wheel 1.6 with a side brake, etc. Modularization and assembly line assembly are conducive to reducing production and management costs and error rates and improving labor productivity.

[0021] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent transformation based on the technical solution of the present invention belongs to the protection scope of the present invention.

Claims

1. A mine hoisting high-voltage frequency conversion cabinet with an online backup power device, characterized in that: The mine hoisting high-voltage frequency conversion cabinet is provided with a power device; the power device includes N-level in-use power devices and at least one level of online backup power device; the outlet terminals A1, B1 and C1 of the first-level in-use power device are connected together to form a three-phase high-voltage power circuit. o The output neutral point Q0 of the output, the output ends of the power devices in use are connected in series in order of A2-A1, B2-B1 and C2-C1 through single-phase high-voltage cables, and the output ends A2, B2 and C2 of the power devices in use at the Nth level are connected to the three-phase input ends of the lifting motor respectively, providing the lifting motor with three-phase high-voltage power with adjustable frequency and voltage. o The outlet terminals A1, B1, C1 and A2, B2, C2 of the online backup power device are in an idle state; the input terminals of the online backup power device and the in-use power device are connected in sequence through three-phase high-voltage cables, and connected to the input terminal of the grid-side power 6kV or 10kV to obtain grid-side power for the mine hoisting high-voltage frequency conversion cabinet. i , so that the high-voltage grid-side power supply with a frequency of 50Hz and a voltage of 6kV or 10kV i After the mine hoisting high-voltage frequency conversion cabinet regulates the voltage and frequency, a three-phase high-voltage power electric with adjustable frequency and voltage is obtained at the hoisting motor end. o , driving the mine hoist to operate; the online backup power device is powered on like the in-use power device but runs at no load, maintaining a good state and characteristics. Once some levels of the in-use power device fail, in a power outage, one or several levels of the online backup power device are used to quickly replace the faulty parts of the in-use power device, so that the mine hoisting high-voltage frequency conversion cabinet can resume normal operation in the shortest time without downgrading or reducing the speed; then the faulty power device is withdrawn and repaired offline. After the faulty power device is repaired and qualified, it is used as part of the online backup power device to resume online no-load operation in time and continue to maintain good quality, and is used in a circular manner, ensuring that the downtime of the mine hoisting high-voltage frequency conversion cabinet due to some reason is controllable and quickly resumes normal operation.

2. A mine hoisting high-voltage frequency conversion cabinet with an online backup power device as claimed in claim 1, characterized in that: The power device is a basic power component for modular and standardized design, packaging and interface of the main circuit of the four-quadrant high-voltage inverter; the power device has three four-quadrant power units and a power transformer; the power transformer has three sets of secondary windings, which are respectively connected to the input ends of the three four-quadrant power units through three-phase low-voltage cables to provide power for the four-quadrant power units; the output ends of the three four-quadrant power units are respectively: A1, A2, B1, B2, C1, C2; the frame member of the power device has four layers, the power transformer is placed on the bottom layer of the frame member, and the three four-quadrant power units are respectively fixed on the insulating parts and placed in the other three layers of the frame member in sequence; the bottom of the frame member is equipped with heavy-duty universal wheels with side brakes to facilitate the rapid movement and positioning of the power device; the mine hoisting high-voltage frequency conversion cabinet is provided with N cooling fans, and the N-level power devices in use are placed under the fans in sequence for cooling during operation.

3. A mine hoisting high-voltage frequency conversion cabinet with an online backup power device according to claim 1 or 2, characterized in that: For the power supply of the mine site network i 6kV or 10kV, the rated phase voltage of the primary winding of the power transformer is 6kV. i When the voltage is 6kV, the primary winding is connected in a triangle Δ manner. i When the voltage is 10kV, the primary winding is connected in a "star Y" manner, and the power transformer can always be connected to the grid-side power supply u i The connection method of the secondary windings of the three sets of power transformers is "delta Δ" or "star Y", and no phase shift is required; the input / output rated voltage of the four-quadrant power unit is designed and selected according to three-phase AC600V / single-phase AC730V. Therefore, the input / output rated voltage of the power transformer is 6 (10) / 3*0.6kV, and the rated capacity is 1.4*P e / N optional, where: P e To increase the rated capacity of the motor, N is the number of the power devices in use, and selection is made based on the output rated voltage of the four-quadrant power unit and the voltage level of the motor.

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