Automatic residual voltage releasing device for overhead line system

Abstract

The utility model discloses an automatic residual voltage release device for a contact network, which is arranged between the contact network and a return rail and comprises a residual voltage release loop, a control unit and a network voltage and network flow signal acquisition module, the residual voltage release loop is connected with the control unit, the input of the network voltage and network flow signal acquisition module is connected with a contact network, and the output is connected with the control unit; the residual voltage discharge loop comprises a high-voltage discharge isolation switch, a control relay module, a first switch, a second switch, a discharge resistor and a power supply module; the high-voltage discharge isolation switch is connected between the positive electrode and the negative electrode of the contact network, the high-voltage discharge isolation switch is connected to a switching value output port of the control unit through the control relay module, and the high-voltage discharge isolation switch is respectively connected with a switching value input port of the power supply module and a switching value input port of the control unit through a first switch and a second switch. According to the utility model, the high-voltage isolating switch is protected, and the high-voltage direct-current isolating switch is prevented from being damaged by electric arcs.

Description

Technical Field

[0001] The utility model relates to the technical field of rail transit traction power supply, in particular to an automatic discharge device for residual pressure of a contact network. Background Art

[0002] To meet the operational and maintenance needs of urban rail transit catenary systems, minimize the impact of faults and accidents, and ensure power supply flexibility during both normal and fault conditions, the catenary system is divided into several power supply sections. During operational maintenance, due to electrostatic induction voltage or low insulation levels in segmented insulators and insulators, the catenary system may still show live voltage after a power outage, a phenomenon known as residual voltage. High residual voltage prevents the visual grounding system from closing, hindering maintenance operations and endangering the safety of maintenance personnel and equipment. This residual voltage phenomenon is primarily concentrated in vehicle depots and parking lots, and often occurs at the entry and exit lines. It is particularly severe in rainy and foggy conditions.

[0003] If the residual pressure of the contact network is discharged to a safe operating voltage by natural discharge, it will be easily affected by factors such as line load, ambient temperature and humidity, resulting in uncontrollable discharge time, thereby increasing the uncertainty of maintenance time and safety during maintenance. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a contact network residual pressure automatic release device, which is installed between the contact network and the return rail. The specific technical solution is as follows:

[0005] The device includes a residual pressure relief circuit, a control unit, and a network voltage and current signal acquisition module;

[0006] The residual pressure relief circuit is connected to the control unit, the input of the network voltage and network current signal acquisition module is connected to the contact network, and the output is connected to the control unit;

[0007] The residual pressure relief circuit includes a high-voltage relief isolation switch, a control relay module, a first switch, a second switch, a relief resistor and a power supply module;

[0008] The high-voltage discharge isolating switch is connected between the positive and negative poles of the contact network, and the high-voltage discharge isolating switch is connected to the switch output port of the control unit through the control relay module. The high-voltage discharge isolating switch is connected to the switch input port of the power supply module and the control unit respectively through the first switch and the second switch.

[0009] Furthermore, the network voltage and network flow signal acquisition module includes a dual network voltage sensor and a network flow sensor;

[0010] The access end of the dual-grid pressure sensor is connected to the positive and negative electrodes of the contact network, and the contact end is connected to the control unit;

[0011] The input end of the network current sensor is connected to the positive pole of the contact network, the output end of the network current sensor is connected to the analog input end of the control unit, and the network current sensor is also connected to the high-voltage discharge isolation switch.

[0012] Furthermore, a fuse is provided between the positive electrode of the contact network and the positive electrode access end of the dual network voltage sensor and the access end of the network current sensor.

[0013] Furthermore, the control relay module includes a first relay group and a third relay group, and the high-voltage discharge isolation switch includes a first discharge isolation switch and a second discharge isolation switch;

[0014] The first discharge isolating switch is connected to the switch output terminal of the control unit through the first relay group;

[0015] The second discharge isolation switch is connected to the output end of the control unit through the third relay group.

[0016] Furthermore, the switch input ends of the first discharge isolating switch and the second discharge isolating switch are respectively connected to the first switch and the second switch, and the switch input ends of the first discharge isolating switch and the second discharge isolating switch are connected in series and then connected between the power module and the control unit.

[0017] Furthermore, the control relay module further includes a second relay group, and the first discharge isolation switch is connected to the switch output end of the control unit through the second relay group.

[0018] Furthermore, a thyristor switch and a discharge resistor are connected in series between the first discharge isolating switch and the second discharge isolating switch.

[0019] Furthermore, the output end of the second relay group connected to the positive pole of the power module is connected to the output end of the thyristor switch through a resistor; the output end of the second relay group connected to the positive pole of the power module is connected to the output end of the thyristor switch.

[0020] Furthermore, the output end of the second relay group connected to the positive pole of the power module is also connected to a diode, and the cathode of the diode is connected to the output end of the thyristor switch.

[0021] The beneficial effects of the utility model are as follows:

[0022] This utility model integrates a catenary residual pressure relief device into a high-voltage catenary disconnect switch cabinet. The catenary residual pressure relief device automatically performs electrical testing and discharge operations before connecting the ground wire. It automatically monitors the residual pressure measured by the voltage sensor circuit and the discharge current detected by the current sensor. If it is determined that the catenary residual pressure exceeds the set threshold, it automatically sends a discharge command, first controlling the closing of the high-voltage DC disconnect switch, and then controlling the closing of the high-current thyristor switch to protect the high-voltage disconnect switch and prevent arc damage to the high-voltage DC disconnect switch. After the thyristor switch is closed, the catenary residual pressure is generated to a safe voltage through the discharge resistor; the discharge voltage and current status are recorded by the PLC, the discharge effect is evaluated, and an exit command is sent. Based on this device, the labor intensity and high-voltage operation skill requirements of the operators are reduced, the safety application factor is improved, and the maintenance cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the circuit principle of the device of the utility model. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in a variety of different configurations. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the utility model product is conventionally placed when in use, or the orientations or positional relationships conventionally understood by those skilled in the art, or the orientations or positional relationships in which the utility model product is conventionally placed when in use. These are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used only to distinguish descriptions and should not be understood as indicating or implying relative importance.

[0026] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0027] Example 1

[0028] The first embodiment of the present invention discloses a device for automatically releasing residual pressure of a contact network. Figure 1 As shown, the device is located between the contact network and the return rail, and its specific structure is as follows:

[0029] The device includes a residual pressure relief circuit, a control unit, and a network voltage and current signal acquisition module;

[0030] The control unit adopts PLC, and the control unit is connected to the touch screen (HMI) or system operation terminal of the rail transit high-voltage electric disconnect switch cabinet (including visual grounding system);

[0031] The residual pressure relief circuit is connected to the control unit, the input of the network voltage and network current signal acquisition module is connected to the contact network, and the output is connected to the control unit;

[0032] The network pressure and network flow signal acquisition module includes a dual network pressure sensor and a network flow sensor TA1;

[0033] The access end of the dual-grid pressure sensor is connected to the positive and negative electrodes of the contact network, and the contact end is connected to the control unit;

[0034] The input end of the network current sensor TA1 is connected to the positive pole of the contact network, the output end of the network current sensor is connected to the analog input end of the control unit, and the network current sensor is also connected to the high-voltage discharge isolation switch.

[0035] As a preferred embodiment, a fuse is further provided between the positive electrode of the contact network and the positive electrode access end of the dual network voltage sensor and the access end of the network current sensor.

[0036] The residual pressure relief circuit includes high-voltage relief isolation switches KM1 and KM2, a control relay module, a thyristor switch SCR1, a relief resistor RL1, and a power supply module;

[0037] The high-voltage discharge isolating switch is connected between the positive and negative poles of the contact network, and the high-voltage discharge isolating switch includes a first discharge isolating switch KM1 and a second discharge isolating switch KM2;

[0038] Specifically, the current conducting end input of the first discharge isolating switch KM1 is connected to the positive terminal of the contact network through the network current sensor TA1 and the fuse;

[0039] The current conduction end output of the first discharge isolation switch KM1 is connected to the current conduction end input of the second discharge isolation switch KM2 through the thyristor switch SCR1 and the discharge resistor RL1. The current conduction end output of the second discharge isolation switch KM2 is connected to the switch input port of the control unit.

[0040] The bleeder resistor RL1 is a high-power wire-wound resistor or an aluminum-shell cement resistor.

[0041] The high-voltage discharge isolation switch is connected to the switch output port of the control unit through the control relay module; the control relay module includes a first relay group and a third relay group;

[0042] The control relay module adopts a high-insulation intermediate relay, with a withstand voltage of more than 4000Vac between the coil and the contact, and an impulse withstand voltage of 10kV (1.2×50μs).

[0043] Specifically, the control end of the first discharge isolation switch KM1 is connected to the relay switch output end of the first relay group, and the first relay group is connected to a DC ±24V power supply;

[0044] The first discharge isolation switch KM1 is connected to the switch output terminal of the control unit through the first relay group;

[0045] The control end of the second discharge isolation switch KM2 is connected to the relay switch output end of the third relay group, and the third relay group is connected to a DC ±24V power supply;

[0046] The second discharge isolation switch is connected to the output end of the control unit through the third relay group.

[0047] As a preferred embodiment, the high-voltage discharge isolation switch is connected to the switch value input ports of the power module and the control unit respectively through a thyristor switch.

[0048] Specifically, the switch input terminal of the first discharge isolation switch KM1 is connected to the first switch KA1, and the first switch KA1 is connected to a DC power supply DC +24V power supply;

[0049] The switch input terminals of the first discharge isolating switch and the second discharge isolating switch are connected in series. The switch input terminal of the second discharge isolating switch is connected to a second switch KA2 and is connected to the switch input port of the control unit through the second switch KA2.

[0050] As a preferred embodiment, the control relay module further includes a second relay group, and the current conducting ends of the first discharge isolation switch KM1 and the second discharge isolation switch KM1 are connected to the switch output end of the control unit through the second relay group.

[0051] Specifically, the output end of the second relay group connected to the positive electrode of the power module is connected to the output end of the thyristor switch SCR1 through a resistor;

[0052] The output end of the second relay group connected to the positive electrode of the power module is connected to the output end of the thyristor switch SCR1, and the thyristor switch SCR1 uses a diode; the second relay group is connected to a DC ±12V power supply;

[0053] The output end of the second relay group connected to the positive electrode of the power module is further connected to a diode D1 , and the cathode of the diode D1 is connected to the output end of the thyristor switch SCR1 .

[0054] Based on the above device, when the device detects that the two normally open contacts of the contact network disconnector are opened at the same time (that is, the contact network disconnector is in the open state), it determines that the measured DC contact network voltage U is a safe voltage.

[0055] When the detected contact network safety voltage value U exceeds the set voltage value U1, the detection unit transmits the voltage signal to the PLC controller, which records and stores the voltage signal and controls the closing of the discharge isolation switches KM1 and KM2 at the same time. Then the thyristor switch SCR1 is turned on and the discharge circuit works, so that the contact network voltage value drops below U2 and the discharge current is less than I1. At this time, the controller determines that the residual pressure discharge completion conditions are met, thereby achieving the purpose of discharging the residual voltage of the DC contact network and avoiding the problem of burning the grounding switch contacts under high voltage conditions.

[0056] Specifically, the terminal sets the threshold values ​​[U1, U2] of the two-level residual voltage U and the threshold value [I1] of the residual current I. For example, based on the above process, the discharge circuit completes the discharge of the residual voltage greater than U1 (e.g., 400V) until the residual voltage of the contact network is less than U2 (e.g., 75V) and the discharge current is less than I1 (e.g., 10mA), thus completing the residual voltage discharge. Based on the above device, the contact network residual pressure discharge device can discharge the contact network residual voltage from U1 (e.g., 400V) to below the lower limit threshold value U2 (e.g., 75V) within 1s.

[0057] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A contact network residual pressure automatic release device, provided between the contact network and the return rail, characterized in that: The device includes a residual pressure relief circuit, a control unit, and a network voltage and current signal acquisition module; The residual pressure relief circuit is connected to the control unit, the input of the network voltage and network current signal acquisition module is connected to the contact network, and the output is connected to the control unit; The residual pressure relief circuit includes a high-voltage relief isolation switch, a control relay module, a first switch, a second switch, a relief resistor and a power supply module; The high-voltage discharge isolating switch is connected between the positive and negative poles of the contact network, and the high-voltage discharge isolating switch is connected to the switch output port of the control unit through the control relay module. The high-voltage discharge isolating switch is connected to the switch input port of the power supply module and the control unit through the first switch and the second switch respectively.

2. The contact network residual pressure automatic release device according to claim 1, characterized in that: The network pressure and network flow signal acquisition module includes a dual network pressure sensor and a network flow sensor; The access end of the dual-grid pressure sensor is connected to the positive and negative electrodes of the contact network, and the contact end is connected to the control unit; The input end of the network current sensor is connected to the positive pole of the contact network, the output end of the network current sensor is connected to the analog input end of the control unit, and the network current sensor is also connected to the high-voltage discharge isolation switch.

3. The contact network residual pressure automatic release device according to claim 2, characterized in that: A fuse is also provided between the positive electrode of the contact network and the positive electrode access end of the dual network voltage sensor and the access end of the network current sensor.

4. The contact network residual pressure automatic release device according to claim 1, characterized in that: The control relay module includes a first relay group and a third relay group, and the high-voltage discharge isolation switch includes a first discharge isolation switch and a second discharge isolation switch; The first discharge isolating switch is connected to the switch output terminal of the control unit through the first relay group; The second discharge isolation switch is connected to the output end of the control unit through the third relay group.

5. The contact network residual pressure automatic release device according to claim 4, characterized in that: The switching input ends of the first discharge isolating switch and the second discharge isolating switch are connected to the first switch and the second switch respectively. The switching input ends of the first discharge isolating switch and the second discharge isolating switch are connected in series and then connected between the power module and the control unit.

6. The contact network residual pressure automatic release device according to claim 4, characterized in that: The control relay module further includes a second relay group, and the first discharge isolation switch is connected to the switch output end of the control unit through the second relay group.

7. The contact network residual pressure automatic release device according to claim 6, characterized in that: A thyristor switch and a discharge resistor are further connected in series between the first discharge isolating switch and the second discharge isolating switch.

8. The automatic discharge device for residual pressure of the contact network according to claim 7, characterized in that: The output end of the second relay group connected to the positive pole of the power module is connected to the output end of the thyristor switch through a resistor; the output end of the second relay group connected to the positive pole of the power module is connected to the output end of the thyristor switch.

9. The contact network residual pressure automatic release device according to claim 8, characterized in that: The output end of the second relay group connected to the positive pole of the power module is also connected to a diode, and the cathode of the diode is connected to the output end of the thyristor switch.

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