External direct current switch cabinet current quick-break protection device

Abstract

The utility model belongs to the technical field of current protection devices, and discloses an external direct current switch cabinet current quick-break protection device, which comprises a PLC module, an opening and closing control loop and a current sampling loop, and is characterized in that the opening and closing control loop is connected in parallel with an opening loop and a closing loop of a circuit breaker in a direct current switch cabinet; the opening and closing control loop comprises an electric latching opening and closing knob S1, a magnetic latching opening and closing knob S4, an opening indicating lamp and a closing indicating lamp; the current sampling loop comprises an analog quantity module, the analog quantity module is connected with a current transmitter in the direct current switch cabinet, and the analog quantity module collects output signals of the current transmitter and feeds back the output signals to the PLC module. According to the utility model, temporary connection of the DC switch cabinet can be realized, rapid switching-on can be carried out, and the DC fault processing efficiency of the power transformation specialty can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of current protection devices, and in particular relates to an external DC switch cabinet current quick-break protection device. Background Art

[0002] The DC switchgear is the main switchgear of the DC traction power supply system of the subway. It is used to stop the power supply of the DC 1500V contact network. At the same time, the DC switchgear is equipped with a relay protection device, which can quickly disconnect the circuit breaker when a short circuit fault occurs in the contact network, and cut off and isolate the fault point of the contact network.

[0003] Due to the maintenance of various specialized equipment after nighttime shutdown, DC switchgear is often required to be opened and closed at night to stop power supply to the contact network. Therefore, the probability of failure of DC switchgear at night is much higher than that of failure during operation.

[0004] There are three types of faults that cannot be solved by the two existing closing methods. The first is the failure of the protection device. The internal board of the protection device is damaged and an abnormal signal appears, which causes the protection device to be unable to output the closing command. When the protection device fails, the opening and closing commands of the DC1500V circuit breaker are all transmitted from the protection outlet to the internal circuit of the circuit breaker trolley through the aviation plug. Therefore, when the protection device fails, the circuit breaker cannot be opened and closed, but it takes a long time to replace the protection device. If the protection device is to be replaced, it may be necessary to change the power supply method to handle this type of fault. The second is that the wiring of the secondary circuit is loose, such as the key signal cannot be input, or the signal cannot be output; when the wiring of the secondary circuit is loose, the protection device cannot receive key node information such as the trolley working position signal and the circuit breaker opening and closing position signal. The protection device logic judges that the closing conditions are not met and refuses to issue a closing command to the circuit breaker trolley. The third is that the secondary circuit components such as relays and switch knobs are damaged. When the secondary circuit components are damaged, such as the contacts of the remote local conversion switch and the opening and closing knob cannot be changed, the closing command or the key signal that meets the closing conditions cannot be input into the protection device; or the opening and closing relay between the output signal of the protection device to the trolley coil is damaged, the circuit breaker cannot be closed. Utility Model Content

[0005] The utility model aims to solve the above technical problems at least to a certain extent. To this end, the utility model aims to provide an external DC switch cabinet current quick-break protection device.

[0006] The technical solution adopted by the utility model is:

[0007] An external DC switch cabinet current quick-break protection device comprises a PLC module, an opening and closing control circuit, a current sampling circuit and a power supply circuit. The opening and closing control circuit is connected in parallel with the opening circuit and the closing circuit of the circuit breaker in the DC switch cabinet; the opening and closing control circuit comprises an electrically held opening and closing knob S1, a magnetically held opening and closing knob S4, an opening indicator light and a closing indicator light. The electrically held opening and closing knob S1, the magnetically held opening and closing knob S4, the opening indicator light and the closing indicator light are all connected to the PLC module; the current sampling circuit comprises an analog quantity module, the analog quantity module is connected to a current transmitter in the DC switch cabinet, the analog quantity module collects the output signal of the current transmitter and feeds it back to the PLC module.

[0008] Preferably, the external DC switch cabinet current quick-break protection device also includes a protection tripping circuit, which includes an overcurrent protection throw-in / out knob S2, a protection reset button S3, an overcurrent alarm indicator light and an overcurrent tripping indicator light. The overcurrent protection throw-in / out knob S2, the protection reset button S3, the overcurrent alarm indicator light and the overcurrent tripping indicator light are all connected to the PLC module.

[0009] Preferably, the external DC switch cabinet current quick-break protection device also includes an impact closing circuit, which includes an impact closing relay K1 and an impact closing contactor J1 controlled by the impact closing relay K1, and the impact closing contactor J1 is connected to the closing coil of the circuit breaker in the DC switch cabinet.

[0010] Preferably, the external DC switch cabinet current quick-break protection device further comprises an electric holding circuit, the electric holding circuit comprises an electric holding relay K2, and the electric holding relay K2 is connected to the holding resistor R1 of the circuit breaker in the DC switch cabinet.

[0011] Preferably, the external DC switch cabinet current quick-break protection device further includes a magnetic latching control circuit, the magnetic latching control circuit includes a magnetic latching relay K7, and the magnetic latching relay K7 is connected to the circuit breaker in the DC switch cabinet.

[0012] Preferably, the power supply circuit includes a pin-type terminal and a DC24V power supply module connected to the pin-type terminal, and the pin-type terminal is connected to a power circuit breaker of a DC switch cabinet.

[0013] The beneficial effects of the utility model are:

[0014] When the two closing methods of local electrical closing and bypass closing provided by the DC switch cabinet itself cannot close the switch, the external DC switch cabinet current quick-break protection device of the utility model can realize temporary takeover of the DC switch cabinet, quickly use the third closing method provided by the device to quickly close the switch, and realize the control, monitoring and protection of the DC switch cabinet. The device can improve the DC fault handling efficiency of the substation profession by more than 50%, and reduce the fault repair and tripping caused by the protection device and secondary circuit problems of the DC switch cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The utility model discloses a circuit diagram of a current quick-break protection device for an external DC switch cabinet.

[0016] Figure 2 It is a schematic diagram of the current sampling circuit of the utility model. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the utility model to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, but not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] It should be understood that it should also be noted that in the embodiment, the functions / actions that appear may be different from the order in which the drawings appear. For example, depending on the functions / actions involved, they can actually be executed substantially concurrently, or two figures shown in succession can sometimes be executed in the reverse order.

[0019] like Figure 1 and Figure 2 As shown, an external DC switch cabinet current quick-break protection device (hereinafter referred to as "this device") of this embodiment is mainly used in the fault handling of the DC1500V DC circuit breaker that cannot be closed in rail transit, and is used to improve the fault handling efficiency. The external DC switch cabinet current quick-break protection device includes a PLC module, a separation and closing control circuit, a current sampling circuit, a protection tripping circuit, an impact closing circuit, an electric holding circuit, a magnetic holding control circuit and a power supply circuit.

[0020] Among them, the opening and closing control circuit is connected in parallel with the opening circuit and closing circuit of the circuit breaker in the DC switch cabinet; the opening and closing control circuit includes an electrically held opening and closing knob S1, a magnetically held opening and closing knob S4, an opening indicator light and a closing indicator light, and the electrically held opening and closing knob S1, the magnetically held opening and closing knob S4, the opening indicator light and the closing indicator light are all connected to the PLC module; the opening and closing functions of the circuit breaker can be realized through the opening and closing control circuit, and the on-site personnel perform opening and closing operations on the electrically held circuit breaker through the electrically held opening and closing knob S1, and perform opening and closing operations on the magnetically held circuit breaker through the magnetically held opening and closing knob S4.

[0021] The current sampling circuit includes an analog module 1, which is connected to the current transmitter 2 in the DC switch cabinet. The analog module 1 collects the output signal of the current transmitter 2 and feeds it back to the PLC module. The PLC module performs digital conversion on the current analog quantity to realize the monitoring of the feeder current value, the alarm and tripping functions of the current quick-break protection. The protection tripping circuit includes an overcurrent protection throw-in / out knob S2, a protection reset button S3, an overcurrent alarm indicator light and an overcurrent tripping indicator light. The overcurrent protection throw-in / out knob S2, the protection reset button S3, the overcurrent alarm indicator light and the overcurrent tripping indicator light are all connected to the PLC module; when the current reaches 60% of the set value, the overcurrent alarm indicator light will light up as a pre-alarm. After the protection fault trips, manual reset is required to close the switch again. The set overcurrent protection throw-in / out knob S2 can determine whether a protection function needs to be added based on the on-site situation.

[0022] The impact closing circuit includes the impact closing relay K1 and the impact closing contactor J1 controlled by the impact closing relay K1. It is mainly used to control the closing of the circuit breaker. The impact closing contactor J1 is connected to the closing coil of the circuit breaker in the DC switch cabinet. During the operation of this device, the DC24V power supply controls the DC220V circuit breaker coil power supply. Since a large current will be generated at the moment of closing, the impact closing circuit uses the impact closing contactor J1 contact with an arc extinguishing device to complete the impact closing to ensure the safety of the device itself. The output time of the closing impact current can also be controlled by the PLC module to protect the circuit breaker closing coil from being affected by long-term continuous large current and affecting its service life, thereby ensuring the safety of the circuit breaker itself.

[0023] The electric holding circuit includes an electric holding relay K2, which is connected to the holding resistor R1 of the circuit breaker in the DC switch cabinet. The impact closing circuit and the electric holding circuit together constitute an electric holding control circuit, which is applied to the electric holding circuit breaker.

[0024] The magnetic latching control circuit is applied to the magnetic latching circuit breaker. The magnetic latching control circuit includes the magnetic latching relay K7, which is connected to the circuit breaker in the DC switch cabinet. By setting the electric latching circuit and the magnetic latching control circuit, it can adapt to the closing and holding mode of the circuit breakers of the two mainstream brands of Jiangsu Daquan and Shanghai Tuoji, so that the device has a wide compatibility and can be used on different types of DC switch cabinets from different manufacturers.

[0025] The power supply circuit includes a pin-type terminal and a DC24V power module 3 connected to the pin-type terminal. The pin-type terminal is connected to the power circuit breaker 4 of the DC switch cabinet, and draws power from the DC 220V power circuit breaker in the switch cabinet to supply power to the impact closing circuit and indicator light in the device. At the same time, the DC24V power module 3 converts 220V DC power into 24V DC power to power PLC modules, relays and other components.

[0026] like Figure 1 As shown, the opening indicator light includes a relay K5 and an LED indicator light connected to the relay K5; the closing indicator light includes a relay K6 and an LED indicator light connected to the relay K6; the overcurrent alarm indicator light includes a relay K4 and an LED indicator light connected to the relay K4; and the overcurrent trip indicator light includes a relay K3 and an LED indicator light connected to the relay K3. The shape and the color of the LED indicator light can be selected according to the requirements of the actual application.

[0027] The external DC switch cabinet current quick-break protection device of the utility model has a complete power supply circuit, a sampling circuit, a control circuit, a signal indication circuit, and is fully functional; and realizes the input and output of control commands through a PLC module.

[0028] Combined with the current DC1500V DC circuit breaker failure type, the three closing methods are compared and analyzed. There are two existing closing methods: the first is the test closing, which is a positive closing method that includes a line test function; the second is the bypass closing, which is a method in which the protection device directly closes without line test logic judgment after the closing command is input into the protection device. The third closing method is provided by the external DC switch cabinet current quick-break protection device of the utility model, which is a closing method that bypasses the protection device and the closing and opening circuit in the cabinet and directly acts on the closing coil of the circuit breaker.

[0029] Table 1 Comparison of three closing methods

[0030]

[0031] Three groups of personnel were set up to solve the circuit breaker failure, and two methods were used to close the circuit breaker. The first method was that the on-site personnel handled the fault according to the traditional disposal method, and the other method was to use this device to handle the fault. The experimental results are shown in Table 2.

[0032] Table 2 Comparison of DC switch cabinet fault handling time

[0033]

[0034] It can be seen from the above two tables that compared with the existing solutions, this device can handle more types of faults and the operation time is shorter. The components of this device are not special, easy to obtain and moderately priced. The DC switch cabinet can be used to purchase spare parts to form the circuit of this device, which greatly reduces the cost of the device. At the same time, it improves the fault handling time, reduces the risk of affecting operations, and increases the stability and reliability of the DC switch power supply.

[0035] It should be noted that the purpose of this device is to replace the protection device, so it is not suitable for the scene of real short-circuit fault in the contact network. It is only suitable for the situation of DC switch cabinet protection device failure as a backup for DC switch cabinet protection device. At the same time, the existing protection device and this device are not allowed to be used at the same time to avoid signal conflicts caused by the simultaneous use of the two devices. That is, this device can be put into use only after the existing protection device is exited; the operation of the existing protection device can be restored only after this device is exited.

[0036] The present utility model is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present utility model. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present utility model fall within the protection scope of the present utility model.

Claims

1. An external DC switch cabinet current quick-break protection device, characterized in that: It includes a PLC module, an opening and closing control circuit, a current sampling circuit and a power supply circuit. The opening and closing control circuit is connected in parallel with the opening circuit and the closing circuit of the circuit breaker in the DC switch cabinet; the opening and closing control circuit includes an electric holding opening and closing knob S1, a magnetic holding opening and closing knob S4, an opening indicator light and a closing indicator light. The electric holding opening and closing knob S1, the magnetic holding opening and closing knob S4, the opening indicator light and the closing indicator light are all connected to the PLC module; the current sampling circuit includes an analog module, the analog module is connected to the current transmitter in the DC switch cabinet, the analog module collects the output signal of the current transmitter and feeds it back to the PLC module.

2. The external DC switch cabinet current quick-break protection device according to claim 1 is characterized in that: It also includes a protection tripping circuit, which includes an overcurrent protection throw-in / out knob S2, a protection reset button S3, an overcurrent alarm indicator light and an overcurrent tripping indicator light. The overcurrent protection throw-in / out knob S2, the protection reset button S3, the overcurrent alarm indicator light and the overcurrent tripping indicator light are all connected to the PLC module.

3. The external DC switch cabinet current quick-break protection device according to claim 1 is characterized in that: It also includes an impact closing circuit, which includes an impact closing relay K1 and an impact closing contactor J1 controlled by the impact closing relay K1. The impact closing contactor J1 is connected to the closing coil of the circuit breaker in the DC switch cabinet.

4. The external DC switch cabinet current quick-break protection device according to claim 1 is characterized in that: It also includes an electric holding circuit, which includes an electric holding relay K2. The electric holding relay K2 is connected to the holding resistor R1 of the circuit breaker in the DC switch cabinet.

5. The external DC switch cabinet current quick-break protection device according to claim 1 is characterized in that: It also includes a magnetic latching control circuit, which includes a magnetic latching relay K7. The magnetic latching relay K7 is connected to the circuit breaker in the DC switch cabinet.

6. The external DC switch cabinet current quick-break protection device according to any one of claims 1 to 5, characterized in that: The power supply circuit includes a pin-type terminal and a DC24V power supply connected to the pin-type terminal. The power module and the pin-type terminal are connected to the power circuit breaker of the DC switch cabinet.

7. The external DC switch cabinet current quick-break protection device according to claim 1 is characterized in that: The opening indicator light and the closing indicator light both include a relay and an LED indicator light connected to the relay.

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