Overvoltage suppression equipment of steel rail potential limiting device

Abstract

The utility model discloses an overvoltage suppression device of a steel rail potential limiting device, when a steel rail potential limiter is switched on, a direct current contactor K2 is switched on, a solid-state relay K3 is switched on, a non-polar capacitor Cs1 is charged by a 220V AC / DC charging loop, when the voltage at the two ends of the non-polar capacitor Cs1 reaches 300V, the solid-state relay K3 is switched off, and the charging process is completed within 3 seconds; when the steel rail potential limiter is switched off and a 25V voltage difference is detected between a steel rail and the ground, the control system triggers the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 to be switched on, so that a reverse current arc extinction loop is formed, and steel rail overvoltage generated when the steel rail potential limiter is switched off is suppressed; and after the capacitor is reversely charged, the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are cut off. According to the invention, a piezoresistor or a lightning arrester is not needed, and when a line suffers from frequent overvoltage impact, the overvoltage of the steel rail can be rapidly suppressed.

Description

Technical Field

[0001] The utility model relates to the technical field of rail voltage monitoring, in particular to an overvoltage suppression device for a rail potential limiting device. Background Art

[0002] The DC side of the subway DC traction power supply system is a suspended ungrounded system, and the rails, which are the main conductors of the return current, are insulated from the ground. However, most of the subway lines currently opened in China have serious problems with high rail potential. In order to ensure personal safety, rail potential limiting devices are generally installed in various stations and sections. When the rail potential reaches the action setting value of sections I and II, the rail is directly grounded through the DC contactor in the rail potential limiting device to clamp the rail potential.

[0003] After the rail potential limiting device is activated, a large amount of traction return current flows directly into the ground through the rail potential limiting device, forming stray current. When the rail potential limiting device is closed and grounded, the stray current leaking from the rail potential limiting device to the ground can reach up to 2000A, causing electrochemical corrosion of underground rails and underground metal structures.

[0004] In view of the above situation, it is necessary to study an overvoltage suppression device suitable for DC traction power supply system. Utility Model Content

[0005] The utility model aims to provide an overvoltage suppression device for a rail potential limiting device, so as to solve the problem of excessively high rail voltage in the above-mentioned background technology.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] An overvoltage suppression device for a rail potential limiting device, comprising an uncontrollable power semiconductor device VD1, an uncontrollable power semiconductor device VD2, a controllable semiconductor device SCR1, a controllable semiconductor device SCR2, a DC contactor K1, a DC contactor K2, a solid-state relay K3, a resistor R1, and a non-polar capacitor CS1, wherein the positive electrode of the uncontrollable power semiconductor device VD1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the non-polar capacitor CS1, the other end of the non-polar capacitor CS1 is connected to the cathode of the controllable semiconductor device SCR2, the negative electrode of the uncontrollable power semiconductor device VD1 is connected to the negative electrode of the controllable semiconductor device SCR2, and the positive electrode of the uncontrollable power semiconductor device VD1 is connected to the negative electrode of the controllable semiconductor device SCR2. The anode of the conductor device SCR1 is connected, the positive electrode of the uncontrollable power semiconductor device VD2 is connected to one end of the resistor R1, and the negative electrode is connected to the anode of the controllable semiconductor device SCR2. The DC contactor K1 is connected to the common connection point between the uncontrollable power semiconductor device VD1 and the controllable semiconductor device SCR1, and the other end is connected to one end of the DC contactor K2. The other end of the DC contactor K2 is connected to the common connection point between the uncontrollable power semiconductor device VD2 and the controllable semiconductor device SCR2. One end of the solid-state relay K3 is connected to one end of the non-polar capacitor CS1, and the other end is connected to the charging end.

[0008] In one embodiment, the uncontrollable power semiconductor device VD1 and the uncontrollable power semiconductor device VD2 are power diodes or a combination of power diodes.

[0009] In one embodiment, the uncontrollable power semiconductor device VD1 and the uncontrollable power semiconductor device VD2 are unidirectionally conductive uncontrollable devices.

[0010] In one embodiment, the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are thyristors or a combination of thyristors.

[0011] In one embodiment, the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are unidirectionally conductive semi-controlled devices.

[0012] In one embodiment, the resistor R1 is a dissipation resistor.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] The overvoltage suppression device of the rail potential limiting device is configured by the coordination of the uncontrollable power semiconductor device VD1, the uncontrollable power semiconductor device VD2, the controllable semiconductor device SCR1, the controllable semiconductor device SCR2, the DC contactor K1, the DC contactor K2, the solid-state relay K3, the resistor R1, and the non-polar capacitor CS1. When the rail potential limiter is closed, the DC contactor K2 is closed, the solid-state relay K3 is turned on, and the 220VAC / DC charging circuit charges the non-polar capacitor Cs1. When the voltage across the non-polar capacitor Cs1 reaches 300V, the solid-state relay K3 is turned off, and the charging process is completed within 3 seconds; when the rail potential limiter is disconnected, when a 25V voltage difference is detected between the rail and the ground, the control system triggers the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 to conduct, forming a reverse current arc extinguishing circuit to suppress the rail overvoltage disconnected by the rail potential limiter; after the capacitor is reversely charged, the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are turned off. This application does not require a varistor or a lightning arrester, and can repeatedly and quickly suppress rail overvoltage when the line is subjected to frequent overvoltage shocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The schematic diagram of the overvoltage suppression device for the rail potential limiting device;

[0016] Figure 2 Schematic diagram of the interaction between the overvoltage suppression equipment and the control system of the rail potential limiting device. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0018] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. On the contrary, when an element is said to be "directly" connected to another element, there is no intermediate element.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0020] See also Figure 1 and Figure 2 : An overvoltage suppression device for a rail potential limiting device, comprising an uncontrollable power semiconductor device VD1, an uncontrollable power semiconductor device VD2, a controllable semiconductor device SCR1, a controllable semiconductor device SCR2, a DC contactor K1, a DC contactor K2, a solid-state relay K3, a resistor R1, and a non-polar capacitor CS1, wherein the positive electrode of the uncontrollable power semiconductor device VD1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the non-polar capacitor CS1, the other end of the non-polar capacitor CS1 is connected to the cathode of the controllable semiconductor device SCR2, and the negative electrode of the uncontrollable power semiconductor device VD1 is connected to the controllable The anode of the semiconductor device SCR1 is connected, the positive electrode of the uncontrollable power semiconductor device VD2 is connected to one end of the resistor R1, and the negative electrode is connected to the anode of the controllable semiconductor device SCR2. The DC contactor K1 is connected to the common connection point between the uncontrollable power semiconductor device VD1 and the controllable semiconductor device SCR1, and the other end is connected to one end of the DC contactor K2. The other end of the DC contactor K2 is connected to the common connection point between the uncontrollable power semiconductor device VD2 and the controllable semiconductor device SCR2. One end of the solid-state relay K3 is connected to one end of the non-polar capacitor CS1, and the other end is connected to the charging end.

[0021] In one embodiment, the uncontrollable power semiconductor device VD1 and the uncontrollable power semiconductor device VD2 are power diodes or a combination of power diodes.

[0022] In one embodiment, the uncontrollable power semiconductor device VD1 and the uncontrollable power semiconductor device VD2 are unidirectionally conductive uncontrollable devices.

[0023] In one embodiment, the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are thyristors or a combination of thyristors.

[0024] In one embodiment, the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are unidirectionally conductive semi-controlled devices.

[0025] In one embodiment, the resistor R1 is a dissipation resistor.

[0026] The overvoltage suppression device of the rail potential limiting device is connected in parallel to both ends of the rail potential limiter. The control terminal is installed in the secondary low-voltage side of the rail potential limiter cabinet. The control terminal and the overvoltage suppression device of the rail potential limiting device communicate using the COM serial port. The control terminal controls the execution of the overvoltage suppression device of the rail potential limiting device by identifying the contacts of the rail potential limiter and monitoring the voltage at both ends of the rail potential limiter. The specific implementation steps are as follows:

[0027] Step 1: When the rail potential reaches the I, II or III action setting value of the rail potential limiter, the DC contactor K1 is triggered to close, and the control terminal recognizes the digital signal of the DC contactor K1 closing, controls the DC contactor K2 to close, and the solid-state relay K3 to turn on, and starts to charge the non-polar capacitor Cs1; when the non-polar capacitor Cs1 is charged to 300V, the control terminal controls the solid-state relay K3 to turn off, and the charging process lasts for 3 seconds;

[0028] Step 2: When the absolute value of the rail potential reaches 25V, the control terminal controls the controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 to be turned on; when the current flows from the rail to the ground, the controllable semiconductor device SCR2 is turned on; when the current flows from the ground to the rail, the controllable semiconductor device SCR1 is turned on; at the same time, the non-polar capacitor Cs1 starts to discharge in reverse to suppress the generation of overvoltage on the rail;

[0029] Step 3: When the non-polar capacitor Cs1 starts to charge in reverse, the controllable semiconductor devices SCR1 and SCR2 are automatically turned off; when the rail potential limiter is fully restored, the control terminal recognizes the restoration signal of the rail potential limiter and controls the DC contactor K2 to open. At this time, the overvoltage suppression process of the rail potential limiter is completed. No varistor or lightning arrester is required. When the line is subjected to frequent overvoltage shocks, the rail overvoltage can be repeatedly and quickly suppressed.

[0030] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An overvoltage suppression device for a rail potential limiting device, characterized in that: The invention comprises an uncontrollable power semiconductor device VD1, an uncontrollable power semiconductor device VD2, a controllable semiconductor device SCR1, a controllable semiconductor device SCR2, a DC contactor K1, a DC contactor K2, a solid-state relay K3, a resistor R1, and a non-polar capacitor CS1. The positive electrode of the uncontrollable power semiconductor device VD1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the non-polar capacitor CS1, the other end of the non-polar capacitor CS1 is connected to the cathode of the controllable semiconductor device SCR2, and the negative electrode of the uncontrollable power semiconductor device VD1 is connected to the The anode of the uncontrollable power semiconductor device VD2 is connected to one end of the resistor R1, and the negative electrode is connected to the anode of the controllable semiconductor device SCR2. The DC contactor K1 is connected to the common connection point between the uncontrollable power semiconductor device VD1 and the controllable semiconductor device SCR1, and the other end is connected to one end of the DC contactor K2. The other end of the DC contactor K2 is connected to the common connection point between the uncontrollable power semiconductor device VD2 and the controllable semiconductor device SCR2. One end of the solid-state relay K3 is connected to one end of the non-polar capacitor CS1, and the other end is connected to the charging end.

2. The overvoltage suppression device of the rail potential limiting device according to claim 1, characterized in that: The uncontrollable power semiconductor device VD1 and the uncontrollable power semiconductor device VD2 are power diodes or combination components of power diodes.

3. The overvoltage suppression device of the rail potential limiting device according to claim 2, characterized in that: The uncontrollable power semiconductor device VD1 and the uncontrollable power semiconductor device VD2 are unidirectionally conductive uncontrollable devices.

4. The overvoltage suppression device of a rail potential limiting device according to claim 1, characterized in that: The controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are thyristors or combination components of thyristors.

5. The overvoltage suppression device of the rail potential limiting device according to claim 4, characterized in that: The controllable semiconductor device SCR1 and the controllable semiconductor device SCR2 are unidirectionally conductive half-controlled devices.

6. The overvoltage suppression device of a rail potential limiting device according to claim 1, characterized in that: The resistor R1 is a dissipation resistor.

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