Fault monitoring device for low-voltage electric appliance distribution box in cable tunnel

Abstract

The utility model discloses a fault monitoring device for a cable tunnel low-voltage apparatus distribution box. The fault monitoring device comprises a first circuit breaker, a fault data acquisition unit, a data concentrator and a power supply unit, the first circuit breaker is arranged on an inlet wire of the distribution box, and the fault data acquisition unit is arranged in the distribution box and is connected with three-phase cables of a distribution box loop; the fault data acquisition unit is connected with a fault signal receiving terminal of the data concentrator, and a voltage wiring terminal of the data concentrator is correspondingly connected with a three-phase cable of a distribution box loop; the data concentrator and the power supply unit are installed in a monitoring box, and the monitoring box is arranged on the outer side of the distribution box. According to the utility model, three-phase current, voltage and residual current of a low-voltage power supply loop in a power cable channel can be monitored in real time, and low-voltage faults can be found in time; on the premise that devices and lines of an original distribution box are not replaced, online monitoring on operation of the existing distribution box can be conveniently and rapidly achieved.

Description

Technical Field

[0001] The utility model relates to the field of distribution box fault monitoring, and particularly relates to a fault monitoring device for a low-voltage electrical distribution box in a cable tunnel. Background Technique

[0002] According to the operation requirements, various low-voltage auxiliary facilities and electrical equipment such as ventilation, lighting, drainage, and on-line monitoring devices are installed in the current power cable tunnel, and are powered through external low-voltage power supply lines and distribution boxes. The circuit breakers and their accessories (such as low-voltage contacts, breaking mechanisms, over- and under-voltage protectors, residual current operated protectors) in the low-voltage distribution box are used to trip and protect against faults such as short circuit, grounding, overload, and under-voltage in the low-voltage circuit, but lack the ability of low-voltage fault diagnosis and on-line monitoring. Once a fault occurs, it will be very difficult to timely obtain the low-voltage power outage warning information and fault type in the tunnel. When a single-phase grounding or short-circuit fault occurs at the end of some low-voltage circuits, since the fault current does not reach the action threshold of the circuit breaker, the circuit breaker cannot be normally opened, resulting in continuous arc and spark generation at the fault point, causing cable fires in the tunnel and triggering large-scale power outage accidents. Since the state of the low-voltage circuit in the tunnel cannot be monitored in real time, it is not until after the low-voltage fault continuously causes tunnel fires and power outages that it can be discovered, which greatly affects the operation safety and reliability of the power cable and the power grid. Content of the Utility Model

[0003] The purpose of the utility model is to provide a fault monitoring device for a low-voltage electrical distribution box in a cable tunnel to solve the problem that the current low-voltage electrical distribution box cannot be normally opened when the fault current does not reach the action threshold of the circuit breaker.

[0004] To solve the above technical problems, the present invention provides a fault monitoring device for a low-voltage electrical distribution box in a cable tunnel, including a first circuit breaker, a fault data acquisition unit, a data concentrator, and a power supply unit; the first circuit breaker is arranged on the incoming line of the distribution box, and the fault data acquisition unit is arranged in the distribution box and is respectively connected to the three-phase cables of the distribution box circuit; the fault data acquisition unit is connected to the fault signal receiving terminal of the data concentrator, and the voltage connection terminals of the data concentrator are respectively connected to the three-phase cables of the distribution box circuit; the data concentrator and the power supply unit are installed in the monitoring box, and the monitoring box is arranged outside the distribution box.

[0005] Further, the power supply unit includes a DC power supply, the input end of the DC power supply is connected to the incoming line end of the distribution box through a second circuit breaker, and the output end of the DC power supply is connected to the power input terminal of the data concentrator.

[0006] Further, the fault data acquisition unit includes a current transformer and a residual current transformer, the output end of the current transformer is connected to the voltage connection terminal of the data concentrator, and the residual current transformer is connected to the residual current connection terminal of the data concentrator.

[0007] Further, the current transformer adopts a perforated current transformer.

[0008] Further, the residual current transformer adopts a perforated residual current transformer.

[0009] Further, the first circuit breaker is a circuit breaker with a shunt release.

[0010] Further, the device further includes an optical switch disposed between the monitoring box and the data concentrator.

[0011] The beneficial effects of the present utility model are as follows:

[0012] 1. It can monitor the three-phase current, voltage, and residual current of the low-voltage power supply circuit in the power cable channel in real time, grasp the operation status of the low-voltage circuit in real time, and promptly detect low-voltage faults.

[0013] 2. By installing this device beside the low-voltage distribution box in the cable tunnel, there is no need to transform the distribution box. Without replacing (damaging) the original components and lines of the distribution box, the on-line monitoring of the operation status and electrical faults of the existing distribution box 8 can be conveniently and quickly achieved.

[0014] 3. In case of an emergency, it can disconnect the low-voltage power supply through remote control to eliminate the fault in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The same reference numerals are used to represent the same or similar parts in these drawings. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0016] Figure 1 is a schematic diagram of an embodiment of the present utility model.

[0017] Figure 2 is an internal structural schematic diagram of the monitoring box of an embodiment of the present utility model.

[0018] Wherein: 1. First circuit breaker; 2. Current transformer; 3. Residual current transformer; 4. Second circuit breaker; 5. DC power supply; 6. Data concentrator; 7. Optical switch; 8. Distribution box; 9. Monitoring box. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] As Figure 1The fault monitoring device for the low-voltage electrical distribution box 8 in the cable tunnel shown includes a first circuit breaker 1, a fault data acquisition unit, a data concentrator 6, and a power supply unit; the first circuit breaker 1 is arranged on the incoming line of the distribution box 9, and the fault data acquisition unit is arranged in the distribution box 8 and is respectively connected to the three-phase cables of the distribution box circuit; the fault data acquisition unit is connected to the fault signal receiving terminal of the data concentrator 6, and the voltage connection terminals of the data concentrator 6 are respectively and correspondingly connected to the three-phase cables of the distribution box circuit; the data concentrator 6 and the power supply unit are installed in the monitoring box 9, and the monitoring box is arranged outside the distribution box 8.

[0020] In this application, the fault data acquisition unit monitors the three-phase current, voltage, and residual current of the low-voltage power supply circuit in the power cable channel in real time. Then, it can master the operation status of the low-voltage circuit in real time and detect low-voltage faults in time. When wiring, one end of the multi-core communication control cable is connected to the distribution box through the idle incoming line hole and waterproof joint of the distribution box 8, a 220V power supply line is connected from the incoming line end of the circuit breaker, the outgoing line end of the circuit breaker is connected to the three-phase voltage detection signal line, and the current transformer, residual current transformer, and shunt trip are connected; then the other end of the cable is connected to the corresponding connection terminals of the data concentrator in the monitoring box 9 and the second circuit breaker; finally, a communication optical fiber is led out from the optical switch and connected to the optical ring network. By installing this device beside the low-voltage distribution box 8 in the cable tunnel, there is no need to transform the distribution box 8, and it can conveniently and quickly realize the online monitoring of the operation status and electrical faults of the existing distribution box 8 without replacing (damaging) the original components and lines of the distribution box 8.

[0021] According to an embodiment of the present application, the power supply unit includes a DC power supply 5. The input end of the DC power supply 5 is connected to the incoming line end of the distribution box 8 through the second circuit breaker 4, and the output end of the DC power supply 5 is connected to the power input terminal of the data concentrator 6. The power supply unit takes 220V power from the incoming line end of the distribution box 8 and accesses the circuit breaker in the device, and supplies power to the data concentrator 6 through the 24V DC power supply 5; in addition, by configuring a 24V output control line and DC energy storage, when an emergency occurs, the monitoring platform can also perform remote tripping and power-off through this control line.

[0022] According to an embodiment of the present application, the fault data acquisition unit includes a current transformer 2 and a residual current transformer 3. The output end of the current transformer 2 is connected to the voltage connection terminal of the data concentrator 6, and the residual current transformer 3 is connected to the residual current connection terminal of the data concentrator 6. Through the concentrator, the three-phase current, voltage, and residual current of the low-voltage power supply circuit in the power cable channel can be monitored in real time.

[0023] According to an embodiment of the present application, the current transformer 2 adopts a perforated current transformer.

[0024] According to an embodiment of the present application, the residual current transformer 3 adopts a perforated residual current transformer.

[0025] According to an embodiment of the present application, the first circuit breaker 1 is a circuit breaker with a shunt trip. In an emergency, the tunnel integrated monitoring platform can send a remote trip command downward. After the data concentrator receives the command, it outputs a 24V control signal to the shunt trip to control the second circuit breaker to trip and achieve remote power-off.

[0026] According to an embodiment of the present application, the device further includes an optical switch 7 disposed between the monitoring box 9 and the data concentrator 6. The data concentrator 6 communicates with the optical switch 7. The optical switch 7 accesses the tunnel monitoring optical fiber ring network through electro-optical signal conversion, uploads the monitoring data to the tunnel integrated monitoring platform, and realizes online monitoring.

[0027] 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 preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A fault monitoring device for low-voltage electrical distribution boxes in cable tunnels, characterized in that, It includes a first circuit breaker, a fault data acquisition unit, a data concentrator and a power supply unit; the first circuit breaker is arranged on the incoming line of the distribution box, and the fault data acquisition unit is arranged in the distribution box and connected to the three-phase cables of the distribution box circuit respectively; The fault data acquisition unit is connected to the fault signal receiving terminal of the data concentrator, and the voltage connection terminals of the data concentrator are respectively and correspondingly connected to the three-phase cables of the distribution box circuit; the data concentrator and the power supply unit are installed in the monitoring box, and the monitoring box is arranged outside the distribution box.

2. The cable tunnel low-voltage electrical distribution box fault monitoring device according to claim 1, wherein The power supply unit includes a DC power supply, the input end of the DC power supply is connected to the incoming line end of the distribution box through a second circuit breaker, and the output end of the DC power supply is connected to the power input terminal of the data concentrator.

3. The cable tunnel low-voltage electrical distribution box fault monitoring device according to claim 1, characterized in that, The fault data acquisition unit includes a current transformer and a residual current transformer, the output end of the current transformer is connected to the voltage connection terminal of the data concentrator, and the residual current transformer is connected to the residual current connection terminal of the data concentrator.

4. The cable tunnel low-voltage electrical distribution box fault monitoring device according to claim 3, characterized in that, The current transformer adopts a through-hole type current transformer.

5. The cable tunnel low-voltage electrical distribution box fault monitoring device according to claim 3, characterized in that, The residual current transformer adopts a through-hole type residual current transformer.

6. The fault monitoring device for low-voltage electrical distribution boxes in cable tunnels according to claim 1, characterized in that, The first circuit breaker is a circuit breaker with a shunt trip.

7. The cable tunnel low-voltage electrical distribution box fault monitoring device according to claim 3, characterized in that, The device further includes an optical switch arranged between the monitoring box and the data concentrator.

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