AC leakage detection system, method and vehicle supporting power supply mode conversion

Abstract

The present invention provides an AC leakage detection system, method and vehicle supporting power supply mode conversion. The system comprises an AC insulation detection device, a leakage current contactor, a leakage detection resistor, a circuit breaker and a controller. The circuit breaker, the leakage current contactor and the AC leakage point detection device are sequentially connected in series and connected between a neutral line and a vehicle. The leakage detection resistor is connected in parallel with the leakage current contactor. The AC insulation detection device is used to detect the vehicle leakage current value and send a warning / alarm signal to the controller. The controller is used to control the leakage current contactor to close or open according to the vehicle state, so that the vehicle auxiliary power supply mode is a TT mode or an IT power supply mode. The present invention does not require the addition of an isolation transformer, thereby reducing the vehicle design cost. When a leakage fault occurs, the system automatically converts to the IT power supply mode, and does not need to cut off the faulty load power supply, thereby reducing the impact on the operation order and improving the vehicle availability.

Description

Technical Field

[0001] The present invention belongs to the technical field of AC leakage detection, and in particular relates to an AC leakage detection system, method and vehicle supporting power supply mode conversion. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The auxiliary power supply system of rail transit vehicles often adopts two power supply modes, TT or IT. The TT power supply mode does not require the addition of an isolation transformer to achieve AC220V power supply, while the TT power supply mode requires the addition of an isolation transformer to achieve AC220V power supply. In addition, in the TT power supply mode, when the load leaks, due to the small loop impedance, the continuous increase in current will cause equipment burnout or even vehicle fire. The faulty unit power supply must be immediately cut off, resulting in vehicle power loss and driving order. In the IT power supply mode, when the load leaks, due to the large loop impedance and small leakage current, the power supply can be maintained without cutting off, and the availability is high, but the leakage detection device must be guaranteed to continuously alarm. In the past, the leakage detection system needed to be configured according to the power supply mode, or an isolation transformer was added to achieve power supply, which required a large investment in equipment costs. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes an AC leakage detection system, method and vehicle supporting power supply mode conversion. The present invention ensures that the auxiliary system works in TT mode when the vehicle works normally, does not need to add an isolation transformer, and reduces the vehicle design cost; when a leakage fault occurs, it automatically converts to IT power supply mode, does not need to cut off the fault load power supply, reduces the impact on the operating order, and improves the vehicle availability.

[0005] According to some embodiments, the present invention adopts the following technical solutions:

[0006] An AC leakage detection system supporting power supply mode conversion includes an AC leakage detection device, a leakage current contactor, a leakage detection resistor, a circuit breaker and a controller, wherein:

[0007] The circuit breaker, the leakage current contactor, and the AC leakage detection device are sequentially connected in series and connected between the neutral line and the vehicle;

[0008] The leakage detection resistor is connected in parallel with the leakage current contactor;

[0009] The AC leakage detection device is used to detect the vehicle leakage current value and send a warning / alarm signal to the controller, and the controller is used to control the leakage current contactor to close or open according to the vehicle state, so that the vehicle auxiliary power supply mode is TT mode or IT power supply mode;

[0010] The leakage detection resistor is used to limit the leakage current within a certain range in the IT power supply mode.

[0011] As an optional implementation, the AC leakage detection device is configured to recover the state of the leakage current contactor, and configure different set current thresholds according to the state of the leakage current contactor.

[0012] As an optional implementation, the AC leakage detection device is used to send a warning signal to the controller in TT mode when the detected leakage current exceeds a first set current threshold, and to send an alarm signal to the controller when the detected leakage current exceeds a second set current threshold.

[0013] As an optional implementation, the AC leakage detection device is used to send an alarm signal to the controller in IT mode when the detected leakage current exceeds a third set current threshold.

[0014] As an optional embodiment, the controller is configured to display warning information through a display device when a warning signal is received to prompt the staff to perform inspection.

[0015] As an optional implementation manner, the controller is configured to control the leakage current contactor to be disconnected when receiving the alarm signal, so that the vehicle auxiliary power supply mode is converted from the TT mode to the IT power supply mode.

[0016] As an optional embodiment, the controller belongs to the vehicle network and communicates with the ground server through a communication network.

[0017] An AC leakage detection method supporting power supply mode conversion comprises the following steps:

[0018] Obtain the vehicle status. When the vehicle is working normally, control the leakage current contactor to close so that the vehicle auxiliary power supply mode works in TT mode.

[0019] The AC leakage detection device detects the vehicle leakage current value, compares the leakage value with the corresponding set current threshold value, generates a corresponding early warning / alarm signal and sends it to the controller;

[0020] When the AC leakage detection device generates an alarm signal, the leakage current contactor is controlled to disconnect, and the vehicle leakage current returns to the neutral line through the leakage detection resistor, so that the vehicle auxiliary power supply mode is converted to IT power supply mode;

[0021] The leakage current value of the vehicle is detected at this time, the leakage value is compared with the corresponding set current threshold, and a corresponding alarm signal is generated and sent to the controller.

[0022] As an optional implementation, according to different auxiliary power supply modes of the vehicle, based on the corresponding leakage current value collected, the single-phase insulation resistance of the vehicle is automatically calculated and recorded.

[0023] A vehicle comprises or is connected to the above-mentioned AC leakage detection system supporting power supply mode conversion.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention can ensure that the auxiliary power supply system works in the TT mode when the vehicle works normally, and does not need to add an isolation transformer, which can reduce the vehicle design cost;

[0026] When a leakage fault occurs, it automatically switches to IT power supply mode without cutting off the power supply of the faulty load, reducing the impact on operational order and improving vehicle availability.

[0027] The AC leakage detection device of the present invention can automatically identify the working mode (TT or IT) of the auxiliary system and calculate the impedance value of the poor insulation of the line.

[0028] The present invention performs an early warning or alarm when the leakage current in the TT mode exceeds the corresponding threshold value, and promptly controls the leakage current contactor to disconnect, and the vehicle leakage current returns to the N line through the current limiting resistor, and the vehicle auxiliary power supply mode is converted from the TT mode to the IT power supply mode. At this time, after the vehicle leakage current is limited by the current limiting resistor, the leakage current value is very small, and will not cause damage to the vehicle equipment or vehicle fire.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 A schematic diagram of the system structure of at least one embodiment of the present invention;

[0032] Figure 2 A schematic diagram of JDK status recovery according to at least one embodiment of the present invention;

[0033] Figure 3 A schematic diagram of leakage in TT mode according to at least one embodiment of the present invention;

[0034] Figure 4 FIG. 4 is a schematic diagram of leakage current in IT mode according to at least one embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] Embodiment 1:

[0039] The invention discloses an AC leakage detection system for high-speed EMU based on the conversion of power supply mode from TT to IT, which can realize the leakage current detection function after the auxiliary power supply mode of high-speed EMU is converted from TT to IT. On the one hand, it ensures the running safety of the vehicle, and on the other hand, it can monitor the leakage current and insulation resistance of the vehicle in real time.

[0040] like Figure 1 As shown, the system consists of five parts: AC leakage detection device, leakage current contactor JDK, leakage detection resistor R, circuit breaker JDN, and vehicle network. The AC leakage detection device detects the vehicle leakage current value and sends warning and alarm signals to the vehicle network. The vehicle network controls JDK according to the vehicle status and realizes the pop-up screen prompt of the alarm signal. The R resistor can limit the leakage current within a certain range.

[0041] When the vehicle is working normally, JDK is closed and the auxiliary power supply system is in TT working mode. The AC leakage detection device measures the leakage current of the vehicle. When the insulation of the auxiliary busbar of the vehicle is normal, the resistance of the busbar to the vehicle body PE is large and the leakage current is small; when the insulation of the busbar is abnormal, the resistance of the busbar to the vehicle body decreases and the leakage current I 漏 Continue to increase, when it exceeds the set value I of the AC leakage detection device 预 or I 报 When the AC leakage detection device sends a warning and alarm signal to the vehicle network.

[0042] When the vehicle network receives a warning signal, the warning information is displayed on the display screen to prompt the vehicle driver and passengers to return to the depot for inspection.

[0043] When the vehicle network receives the alarm signal, the vehicle network displays the alarm information on the display screen on the one hand, and controls the JDK to disconnect on the other hand, and the vehicle leakage current returns to the N line through the resistor R, and the vehicle auxiliary power supply mode is converted from the TT mode to the IT power supply mode. At this time, the vehicle leakage current is limited by the current limiting resistor R, and the leakage current value is very small, which will not cause damage to the vehicle equipment or vehicle fire.

[0044] In order to ensure that the AC leakage detection device can still detect and alarm leakage current in IT mode, it is necessary to send the JDK status back to the AC leakage detection device, such as Figure 2 When the AC leakage detection device detects that JDK is closed, the auxiliary power supply system is in TT working mode, and the leakage alarm threshold is I TT ; When JDK is detected to be disconnected, the auxiliary power supply system is in IT working mode, and the leakage alarm threshold is I IT ; Thus, leakage current alarm can be realized in both TT and IT working modes, and leakage current value can be recorded in real time.

[0045] In TT working mode, the leakage current detection circuit is as follows Figure 3 As shown, since the insulation impedance is much smaller than the three-phase capacitive reactance,

[0046] I 漏 Approximately I 5 , Insulation resistance:

[0047] R=U N / I 漏 (1)

[0048] U N It is the single-phase rated voltage, generally 220V; I 漏 Can be measured by a leakage detection device.

[0049] In IT working mode, the leakage current detection circuit is as follows Figure 4 As shown, the capacitance of the U, V, W, and N lines to ground is basically the same, approximately C (which can be determined by testing the current vehicle). JDK is disconnected, and the R1 resistor is connected in series to the leakage detection circuit. The following is calculated by circuit analysis:

[0050]

[0051] U N It is the single-phase rated voltage, generally 220V; I 漏 Can be measured by leakage detection device; R 1 For the design, a current limiting resistor is selected, generally 3-10K; C can be measured by an LCR tester on the vehicle and then solidified into the calculation software.

[0052] The insulation detection device confirms the power supply mode (TT or IT) of the auxiliary power supply system by collecting the JDK status. When working in the TT mode, the insulation resistance value is calculated using formula (1); when working in the IT mode, the insulation resistance value is calculated using formula (2);

[0053] The insulation test calculation results are indicated on the display interface of the insulation test device, or the insulation resistance value is displayed on the network monitoring screen through network communication, or even sent to the ground server through the vehicle body communication wireless network.

[0054] Embodiment 2:

[0055] A rail transit vehicle is provided with the detection system of the first embodiment.

[0056] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. An AC leakage detection system supporting power supply mode conversion, characterized in that: It includes an AC leakage detection device, a leakage current contactor, a leakage detection resistor, a circuit breaker and a controller, wherein: The circuit breaker, the leakage current contactor, and the AC leakage detection device are sequentially connected in series and connected between the neutral line and the vehicle; The leakage detection resistor is connected in parallel with the leakage current contactor; The AC leakage detection device is used to detect the vehicle leakage current value and send a warning / alarm signal to the controller, and the controller is used to control the leakage current contactor to close or open according to the vehicle state, so that the vehicle auxiliary power supply mode is TT mode or IT power supply mode; The leakage detection resistor is used to limit the leakage current within a certain range in the IT power supply mode.

2. The AC leakage detection system supporting power supply mode conversion according to claim 1, characterized in that: The AC leakage detection device is configured to recover the state of the leakage current contactor, and configure different set current thresholds according to the state of the leakage current contactor.

3. An AC leakage detection system supporting power supply mode conversion as claimed in claim 1 or 2, characterized in that: The AC leakage detection device is used to send a warning signal to the controller in the TT mode when the detected leakage current exceeds the first set current threshold, and send an alarm signal to the controller when the detected leakage current exceeds the second set current threshold.

4. An AC leakage detection system supporting power supply mode conversion as claimed in claim 1 or 2, characterized in that: The AC leakage detection device is used to send an alarm signal to the controller when the detected leakage current exceeds a third set current threshold in the IT power supply mode.

5. The AC leakage detection system supporting power supply mode conversion according to claim 1, characterized in that: The controller is configured to display warning information through a display device when a warning signal is received to prompt the staff to perform inspection.

6. The AC leakage detection system supporting power supply mode conversion according to claim 1, characterized in that: The controller is configured to control the leakage current contactor to disconnect when receiving an alarm signal, so that the vehicle auxiliary power supply mode is changed from the TT mode to the IT power supply mode.

7. The AC leakage detection system supporting power supply mode conversion according to claim 1, characterized in that: The controller belongs to the vehicle network and communicates with the ground server through the communication network.

8. An AC leakage detection method supporting power supply mode conversion, characterized in that: The AC leakage detection system supporting power supply mode conversion as described in any one of claims 1 to 7 comprises the following steps: Obtain the vehicle status. When the vehicle is working normally, control the leakage current contactor to close so that the vehicle auxiliary power supply mode works in TT mode. The AC leakage detection device detects the vehicle leakage current value, compares the leakage value with the corresponding set current threshold value, generates a corresponding early warning / alarm signal and sends it to the controller; When the AC leakage detection device generates an alarm signal, the leakage current contactor is controlled to disconnect, and the vehicle leakage current returns to the neutral line through the leakage detection resistor, so that the vehicle auxiliary power supply mode is converted to IT power supply mode; The leakage current value of the vehicle is detected at this time, the leakage value is compared with the corresponding set current threshold, and a corresponding alarm signal is generated and sent to the controller.

9. The AC leakage detection method supporting power supply mode conversion according to claim 8, characterized in that: According to the different auxiliary power supply modes of the vehicle, the single-phase insulation resistance of the vehicle is automatically calculated and recorded based on the corresponding leakage current value collected.

10. A vehicle, characterized by: The invention comprises or is connected with the AC leakage detection system supporting power supply mode conversion according to any one of claims 1 to 7.

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