CN219873231U - Grounding device suitable for special reflux of urban rail transit - Google Patents

Abstract

The utility model relates to the technical field of rail transit traction power supply, in particular to a special reflux grounding device suitable for urban rail transit, which comprises a compound switch composed of a direct current contactor and an electric isolating switch, wherein the direct current contactor is connected with a negative electrode reflux rail and a grounding busbar to realize quick grounding, the electric isolating switch is connected in parallel at two ends of the direct current contactor and is positioned in a loop formed by the direct current contactor, the negative electrode reflux rail and the grounding busbar, and the switching-on and switching-off state of the electric isolating switch and the switching-on and switching-off state of the direct current contactor are mutually follow-up. The utility model has the advantages that: the personal safety of operation and maintenance personnel during overhaul work is ensured, and the safety is high; simple and reasonable structure, good economy, convenient practical application and suitability for popularization.

Description

A grounding device suitable for special return flow in urban rail transit

Technical field

The utility model relates to the technical field of rail transit traction power supply, in particular to a grounding device suitable for special return flow of urban rail transit, in particular to a grounding device used in a DC traction power supply system of urban rail transit.

Background technique

The positive and negative poles of the DC system for urban rail transit traction power supply are installed with insulation. Due to operation and short-circuit current, impermissible contact voltage will be generated between the negative return circuit and the structural ground. According to the IEC62128-1/EN 50122-1 standard , it is necessary to limit the voltage between the negative pole and the ground to prevent damage to personal safety. At present, how to design a device to facilitate the grounding of the negative return loop to ensure personal safety is an urgent technical problem that needs to be solved.

Contents of the invention

The purpose of this utility model is to provide a grounding device suitable for the special return flow of urban rail transit based on the above-mentioned shortcomings of the existing technology. When the return flow of the negative electrode special rail needs to be grounded, it can achieve rapid grounding and at the same time provide a path for possible fault currents. It can achieve reliable grounding of the negative pole to the ground, clamp the contact voltage to absolute zero potential of the earth, and ensure the personal safety of operation and maintenance personnel during maintenance work.

The purpose of this utility model is achieved by the following technical solutions:

A grounding device suitable for special return flow of urban rail transit, characterized in that: the device includes a composite switch composed of a DC contactor and an electric isolating switch, wherein the DC contactor is connected to the negative return rail and the grounding busbar to achieve rapid Grounding, the electric isolating switch is connected in parallel at both ends of the DC contactor and is located in the loop formed by it, the negative return rail and the grounding busbar. The opening and closing state of the electric isolating switch is related to the DC contactor. The opening and closing states of the contactors follow each other.

The opening and closing state of the electric isolating switch and the opening and closing state of the DC contactor follow each other, which means that when the DC contactor is closed and the circuit of the negative return rail is short-circuited when grounded, the The electric isolating switch is closed as a result; when it is not grounded, the electric isolating switch is disconnected, and the DC contactor is disconnected as a result.

The opening and closing states of the DC contactor and the electric isolation switch are controlled by a PLC controller.

The advantages of this utility model are: it ensures the personal safety of operation and maintenance personnel during maintenance work and is highly safe; it has a simple and reasonable structure, is economical, is convenient for practical application, and is suitable for promotion.

Description of the drawings

Figure 1 is a schematic diagram of the main circuit and secondary circuit power supply wiring of the present utility model;

Figure 2 is a schematic diagram of the control loop of the present utility model;

Figure 3 is a schematic diagram of the signal loop of the present utility model;

Figure 4 is a PLC control principle diagram of the present utility model.

Implementation

The features of the present utility model and other related features will be further described in detail through examples in conjunction with the accompanying drawings to facilitate the understanding of those skilled in the industry:

As shown in Figure 1-4, marks 1-4 in the figure are respectively: negative return rail 1, grounding busbar 2, DC contactor 3, and electric isolation switch 4.

Embodiment: As shown in Figures 1 to 4, in this embodiment, the grounding device suitable for urban rail transit special return is used to achieve reliable grounding when the negative return rail 1 needs to be grounded, and at the same time provide a path for possible fault currents.

As shown in Figure 1, the grounding device in this embodiment includes a composite switch composed of a DC contactor 3 and an electric isolation switch 4. Among them, the DC contactor 3 is connected between the negative return rail 1 and the ground busbar 2 . When the operation and maintenance personnel need to perform maintenance work in the power outage interval, the negative pole of the DC power supply system and the grounding system are short-circuited by closing the DC contactor 3, and rapid grounding is achieved through the grounding device in this embodiment. The electric isolating switch 4 is connected in parallel at both ends of the DC contactor 3 and is located in the loop formed by it, the negative return rail 1 and the ground busbar 2, and the opening and closing state of the electric isolating switch 3 is consistent with the opening and closing state of the DC contactor 3 Follow each other.

Specifically, when grounding, the grounding device first closes the DC contactor 3 to short-circuit the negative return rail 1 to the ground reliably to reduce the excessive voltage that may be generated; at this time, the electric isolation switch 4 follows and closes, On the one hand, it ensures sufficient short-circuit capacity; on the other hand, it ensures that the control power supply loses power and causes the DC contactor 3 to separate, causing invalid grounding and threatening personal safety.

When not grounded, the grounding device first separates the electric isolating switch 4, and the DC contactor 3 follows to ensure the no-load operation of the electric isolating switch 4. After the electric isolating switch 4 is disconnected in place, the DC contactor 3 is opened to complete the disconnection operation. The system returns to the insulated state of negative return rail 1.

During specific implementation of this embodiment: the DC contactor 3 and the electric isolation switch 4 can be controlled by a PLC controller.

The signal loops such as the opening/closing status of the electric isolation switch 4, the opening/closing status of the DC contactor 3, the working status of the PLC controller, and the power supply status are shown in Figure 3 to monitor the working status of the main components.

The control loop of the PLC controller can be designed as shown in Figure 4 to realize the remote control function and data background upload, further improving the use effect of the grounding device, especially ensuring its safety.

Although the above embodiments have described in detail the concepts and embodiments of the present utility model with reference to the accompanying drawings, those of ordinary skill in the art can realize that the present utility model can still be modified without departing from the scope of the claims. There are various improvements and transformations, so I won’t go into details here.

Claims (3)

1. The utility model provides a grounding device suitable for special backward flow of urban rail transit which characterized in that: the device comprises a compound switch composed of a direct current contactor and an electric isolating switch, wherein the direct current contactor is connected with a negative electrode backflow rail and a grounding busbar to realize quick grounding, the electric isolating switch is connected in parallel with two ends of the direct current contactor and is positioned in a loop formed by the electric isolating switch, the negative electrode backflow rail and the grounding busbar, and the switching-on and switching-off state of the electric isolating switch and the switching-on and switching-off state of the direct current contactor are mutually follow-up.

2. The grounding device suitable for urban rail transit special backflow according to claim 1, characterized in that: the following of the on-off state of the electric isolating switch and the on-off state of the direct current contactor means that: when the direct current contactor is closed and the loop of the negative electrode reflux rail is short-circuited, the electric isolating switch is closed in a follow-up way; when the electric isolating switch is not grounded, the electric isolating switch is separated, and the direct current contactor is separated in a follow-up way.

3. The grounding device suitable for urban rail transit special backflow according to claim 1, characterized in that: the switching state of the direct current contactor and the electric isolating switch is controlled by a PLC controller.