Internal power supply system of underground coal mine high-voltage power distribution device

Abstract

The utility model relates to an internal power supply system of an underground coal mine high-voltage power distribution device, which comprises an input rectifying unit, a first energy storage unit, at least two output circuits and a second energy storage unit, and is arranged in the corresponding high-voltage power distribution device, and the power supply among the internal power supply systems of the high-voltage power distribution devices cannot influence each other. When a certain power supply system goes wrong, the situation that an accident expands cannot occur, and the power supply system does not need to work at high power; the power supply system can supply power to the opening coil, the no-voltage trip coil and the protector through the two output circuits, and the first energy storage unit can be automatically used as a backup power supply under the condition of power failure of the power supply. And under the action of the second energy storage unit, the opening coil can carry out at least one reliable opening operation or the no-voltage tripping coil can carry out at least one reliable no-voltage tripping operation, so that the underground power distribution device can be reliably opened under the condition of alternating current power loss.

Description

Technical Field

[0001] This utility model belongs to the field of underground power supply technology in coal mines, and particularly relates to an internal power supply system for an underground high-voltage power distribution device in a coal mine. Background Technology

[0002] High-voltage power distribution equipment in underground coal mines plays a crucial role in power transmission and distribution within the underground high-voltage power grid. The highly reliable operation of this equipment is directly related to the safe production of the coal mine, making its function extremely important. The secondary low-voltage electrical equipment within these equipment typically uses a PT (voltage transformer) power supply mode. This involves converting 6KV or 10KV high-voltage electricity into low-voltage AC 100V. The integrated protection devices and undervoltage release coils within the distribution equipment use this AC 100V as their power source, and simultaneously, this AC 100V is rectified and stepped down to output 24V DC to power the trip coils. However, in the actual operation of high-voltage power distribution equipment in coal mines, when a lightning surge, leakage, or short circuit causes a grid voltage flashover fault, the grid voltage will suddenly drop for a short period of time (usually tens to hundreds of milliseconds). At this time, it is easy to cause the undervoltage trip coil to malfunction, resulting in a large-scale tripping accident. The integrated protection device cannot work properly without backup power supply. Even if some switches have backup power supply inside the integrated protection device and issue a trip command, the trip coil does not have enough voltage to make the switch trip. At the same time, due to the power supply problem, the fault information cannot be transmitted to the ground monitoring center. This situation is very detrimental to the safe operation and information-based operation of the coal mine.

[0003] To address the issue of widespread power outages caused by grid flashover faults in high-voltage power distribution equipment used in Chinese coal mines, many manufacturers have proposed various solutions. For example, some manufacturers design and produce high-power, centralized explosion-proof UPS power supply cabinets that centrally supply power to the integrated protection devices of all high-voltage power distribution equipment switches in underground coal mine substations. These cabinets are also equipped with battery banks as backup power. When significant grid voltage fluctuations, short circuits, or grid flashovers occur, the backup battery bank from the centralized UPS power supply cabinet continues to supply power to the integrated protection devices of each high-voltage power distribution equipment switch, ensuring their normal operation. However, this method also has significant drawbacks, as analyzed below: While the backup battery bank of the centralized explosion-proof UPS power supply cabinet can continue to supply power to the integrated protection devices during significant grid voltage fluctuations, short circuits, or grid flashovers, ensuring their normal operation, the undervoltage release coils inside the high-voltage power distribution equipment lack a separate power supply, which can still lead to malfunctions of the high-voltage circuit breakers. Furthermore, in centralized UPS power supply systems, a UPS malfunction can cause all high-voltage distribution equipment protectors in the substation to malfunction, or even lose backup power, leading to escalating accidents. This is a major drawback of centralized UPS power supplies. Additionally, when high-voltage distribution equipment uses a centralized UPS power supply mode, the centralized UPS must be able to provide high-power output to ensure that multiple switches can trip and close simultaneously and instantaneously; otherwise, there is a risk of switch tripping or closing failures. Based on the above analysis, we need to find a more practical and feasible power supply method for high-voltage distribution equipment in underground coal mines. Utility Model Content

[0004] Based on this, and in response to the aforementioned technical problems, an internal power supply system for a high-voltage power distribution device in a coal mine is provided.

[0005] The technical solution adopted in this utility model is as follows:

[0006] An internal power supply system for a high-voltage power distribution device in a coal mine is characterized in that the system is installed inside the corresponding high-voltage power distribution device and includes an input rectifier unit, a first energy storage unit, at least two output circuits, and a second energy storage unit. The input rectifier unit is connected to the AC power converted by the voltage transformer on the internal bus of the high-voltage power distribution device and is connected to the first energy storage unit. The input terminals of the at least two output circuits are connected to the input rectifier unit and the first energy storage unit. The output terminal of one output circuit is connected to the trip coil and the undervoltage release coil, and the output terminal of the other output circuit is connected to a protector. The output circuit includes an electronic switch unit for adjusting the output voltage of an isolation transmitter output unit, an isolation transmitter output unit, a rectifier output unit, and a feedback unit for feeding back the output voltage of the rectifier output unit to the electronic switch unit. The electronic switch unit is connected to the input terminal of the rectifier output unit via the isolation transmitter output unit. The feedback unit is connected to the output terminal of the rectifier output unit and the electronic switch unit. The second energy storage unit is connected to the rectifier output unit of the output circuit connected to the trip coil and the undervoltage release coil.

[0007] This invention does not provide centralized power supply for all high-voltage power distribution devices, but rather integrates power supply within the corresponding high-voltage power distribution devices. The power supply systems within each high-voltage power distribution device do not interfere with each other. When a problem occurs in one power system, the accident will not escalate, and the power system does not require high-power operation. The power system provides power to the trip coil, undervoltage release coil, and protector through two output circuits. In the event of a power outage, the first energy storage unit automatically acts as a backup power source. Furthermore, with the assistance of the second energy storage unit, the trip coil can perform at least one reliable tripping operation, or the undervoltage release coil can perform at least one reliable undervoltage release operation. This ensures reliable tripping of the underground power distribution devices in the event of an AC power outage. It solves the problem of "false tripping" and "failure to tripping" leading to large-scale power outages caused by malfunctions of the undervoltage release coil, lack of backup power for the protector, and lack of backup power for the trip coil when there are large fluctuations in grid voltage, short circuits, or grid flashovers. This allows for reliable isolation of power supply fault points, reduces the scope of power outages, and ensures safe production in coal mines. Attached Figure Description

[0008] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0009] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0010] This specification provides an internal power supply system for a high-voltage power distribution device in a coal mine. This system corresponds one-to-one with the high-voltage power distribution device, and multiple systems are respectively installed inside the corresponding high-voltage power distribution device. The power supply between the internal power supply systems of each high-voltage power distribution device will not affect each other.

[0011] This specification uses a coal mine underground high-voltage power distribution device as an example, which serves as the busbar, to illustrate its internal power system. Figure 1 As shown, the power supply system includes two input isolation units 110, two input rectifier units 120, an input filter unit 130, a first energy storage unit 140, a first output circuit 150, a second output circuit 160, a third output circuit 170, and a second energy storage unit 180.

[0012] The two input rectifier units 120 are respectively connected to the AC power converted by the two sets of bus voltage transformers inside the underground high-voltage power distribution device via an input isolation unit 110.

[0013] Among them, two sets of bus voltage transformers convert 6KV or 10KV electricity into secondary phase-to-phase voltage of 100V AC. This AC power is connected to Ua1 / Ub1 / Uc1 and Ua2 / Ub2 / Uc2 of the power system in this embodiment as a three-phase power supply.

[0014] The two input rectifier units 120 are connected to the input terminals of the first energy storage unit 140, the first output circuit 150, the second output circuit 160, and the third output circuit 170 via the input filter unit 130.

[0015] The AC power input from Ua1 / Ub1 / Uc1 and Ua2 / Ub2 / Uc2 enters the input filter unit 130 through the corresponding input isolation unit 110 and input rectifier unit 120, respectively. After being filtered by the input filter unit 130, the total input DC power is output. The total input DC power is stored in the first energy storage unit 140 and input to power the first output circuit 150, the second output circuit 160 and the third output circuit 170. The three output circuits do not affect each other.

[0016] The first energy storage unit 140 is also connected to the input terminals of the first output circuit 150, the second output circuit 160, and the third output circuit 170, and can supply power to the three of them.

[0017] The output terminal of the first output circuit 150 is connected to the trip coil 2 and the undervoltage release coil 3 to form a 24V first DC output circuit. The output terminal of the second output circuit 160 is connected to the protector 4, the display screen 5 and the intrinsically safe keyboard 6 to form a 24V second DC output circuit. The output terminal of the third output circuit 170 is connected to the circuit breaker 7, the three-position switch operating power supply 8 and the energy storage motor power supply 9 to form a 24V third DC output circuit.

[0018] In the event of a power outage, the first energy storage unit 140 can automatically act as a backup power source to continue providing power to the first DC output circuit, the second DC output circuit, and the third DC output circuit. When the first DC output circuit performs a circuit breaker opening operation or the third DC output circuit performs a circuit breaker closing operation, a three-position motor switching operation, or an energy storage motor energy storage operation, the first energy storage unit 140 provides instantaneous power to the operating circuits to ensure normal power supply to the aforementioned operating circuits during peak current surges lasting tens of milliseconds.

[0019] The first output circuit 150, the second output circuit 160, and the third output circuit 170 have the same structure. Taking the first output circuit 150 as an example, it includes an electronic switch unit 151, an isolation transmitter output unit 152, a rectifier output unit 153, and a feedback unit 154. The electronic switch unit 151 is connected to the input terminal of the rectifier output unit 153 via the isolation transmitter output unit 152. The rectifier output unit 153 has a filtering function. The feedback unit 154 is connected to the output terminal of the rectifier output unit 153 and the electronic switch unit 151. The electronic switch unit 151 is powered by the total input DC power and is composed of a PWM power control chip and a field-effect transistor, used to adjust the isolation... The output voltage of the transmitter output unit 152 is rectified by the rectifier output unit 153 to output a 24V DC voltage to the trip coil 2 and the undervoltage release coil 3. When the voltage of the first DC output circuit deviates, it is adjusted in real time by the feedback unit 154 to prevent the voltage of the first DC output circuit from deviating too much. The feedback unit 154 is mainly composed of commonly used sampling resistors and isolation operational amplifier circuits. The sampling resistors feed back the output voltage of the rectifier output unit 153 to the electronic switch unit 151, so that the electronic switch unit 151 adjusts the PWM output of the PWM power control chip in real time, and further adjusts the output voltage of the isolation transmitter output unit 152.

[0020] The second energy storage unit 180 is connected to the rectifier output unit 153 of the first output circuit 150. When the power supply of Ua1 / Ub1 / Uc1 or Ua2 / Ub2 / Uc2 fails, the second energy storage unit 180 can automatically serve as a backup power supply to continue to provide power to the first DC output circuit, so that the first DC output circuit can perform at least one reliable tripping operation or undervoltage tripping operation, ensuring reliable tripping of the downhole power distribution device in the event of AC power failure.

[0021] In this embodiment, both the first energy storage unit and the second energy storage unit use supercapacitor banks.

[0022] It should be noted that for non-busbar-connected underground high-voltage power distribution equipment in coal mines, the two input isolation units 110 and the two input rectifier units 120 in their internal power supply system can all be omitted as one, that is, it is not necessary to connect to the power supply of Ua2 / Ub2 / Uc2.

[0023] Among them, the isolation unit 110, input rectifier unit 120, input filter unit 130, electronic switch unit 151, isolation transmitter output unit 152, rectifier output unit 153, feedback unit 154, first energy storage unit 140 and second energy storage unit 180 can all be commercially available products.

[0024] As can be seen from the above, the internal power supply system of the underground high-voltage power distribution device provided in this application embodiment does not provide centralized power supply for all high-voltage power distribution devices, but is set inside the corresponding high-voltage power distribution devices. The power supply between the internal power supply systems of each high-voltage power distribution device will not affect each other. When a problem occurs in a power supply system, the accident will not escalate. Moreover, the power supply system does not need to operate at high power. The power supply system can provide power to the trip coil, the undervoltage release coil, and the protector through two output circuits. In the event of a power supply failure, the first energy storage unit can automatically serve as a backup power source, and the second energy storage unit can also provide backup power. Under the action of the unit, the trip coil can perform at least one reliable trip operation or the undervoltage trip coil can perform at least one reliable undervoltage trip operation, ensuring reliable tripping of the underground power distribution device in the event of AC power failure. This solves the problem of "false tripping" and "failure to tripping" that cause large-scale power outages in the power grid due to the undervoltage trip coil of the high-voltage power distribution device malfunctioning, the lack of backup power supply for the protector, and the lack of backup power supply for the 24V trip coil when there are large fluctuations in grid voltage, short circuits, or grid flashovers. This allows for reliable isolation of power supply fault points, reduces the scope of power outages, and ensures safe production in coal mines.

[0025] Furthermore, the internal power supply system of a high-voltage power distribution device for underground coal mines provided in this application embodiment can also provide power for large-size 7-inch or 10-inch color LCD screens, intrinsically safe keyboards, and three-position switch operating power supplies, in relation to the current novel switches.

[0026] However, those skilled in the art should recognize that the above embodiments are only used to illustrate the present utility model and are not intended to limit the present utility model. Any changes or modifications to the above embodiments within the scope of the essential spirit of the present utility model will fall within the scope of the claims of the present utility model.

Claims

1. An internal power supply system of a high-voltage power distribution device in a coal mine, characterized by, The system is installed inside the corresponding high-voltage power distribution device and includes an input rectifier unit, a first energy storage unit, at least two output circuits, and a second energy storage unit. The input rectifier unit is connected to the AC power converted by the bus voltage transformer inside the underground high-voltage power distribution device and is connected to the first energy storage unit. The input terminals of the at least two output circuits are connected to the input rectifier unit and the first energy storage unit. The output terminal of one output circuit is connected to the trip coil and the undervoltage release coil, and the output terminal of the other output circuit is connected to the protector. The output circuit includes an electronic switch unit for adjusting the output voltage of the isolation transmitter output unit, an isolation transmitter output unit, a rectifier output unit, and a feedback unit for feeding back the output voltage of the rectifier output unit to the electronic switch unit. The electronic switch unit is connected to the input terminal of the rectifier output unit via the isolation transmitter output unit. The feedback unit is connected to the output terminal of the rectifier output unit and the electronic switch unit. The second energy storage unit is connected to the rectifier output unit of the output circuit that connects to the trip coil and the undervoltage release coil.

2. The internal power supply system of a high-voltage power distribution device for underground coal mines according to claim 1, characterized in that, For the underground high-voltage power distribution device in the coal mine, which serves as the busbar, there are two input rectifier units. The two input rectifier units are respectively connected to the AC power converted by the two sets of busbar voltage transformers inside the underground high-voltage power distribution device.

3. The internal power supply system of a high-voltage power distribution device in a coal mine according to claim 1 or 2, characterized in that, The input rectifier unit is connected to the AC power converted by the bus voltage transformer inside the downhole high-voltage power distribution device via the input isolation unit.

4. The internal power supply system of a high-voltage power distribution device for underground coal mines according to claim 3, characterized in that, The input rectifier unit is connected to the input terminal of the first energy storage unit and the output circuit via the input filter unit.

5. The internal power supply system of a high-voltage power distribution device for underground coal mines according to claim 1, characterized in that, The number of output circuits is three. The output terminal of another output circuit is also connected to the display screen and the intrinsically safe keyboard. The output terminal of the remaining output circuit is connected to the circuit breaker, the three-position switch operating power supply and the energy storage motor power supply.

6. The internal power supply system of a high-voltage power distribution device in a coal mine according to claim 1, characterized in that, Both the first energy storage unit and the second energy storage unit are supercapacitor banks.

7. The internal power supply system of a high-voltage power distribution device in a coal mine according to claim 1, characterized in that, The rectifier output unit has a filtering function.

Images