Overhead line system alternating current and direct current network voltage detection device for dual-power-supply train

Abstract

The invention discloses a contact network AC / DC network voltage detection device for a dual-power-supply train, and the device comprises a high-voltage mutual inductor, the output end of a primary winding of the high-voltage mutual inductor is connected with a steel rail through a current-limiting resistor, an output cable of the primary winding is provided with a Hall sensor, and the current on the output cable is detected in real time. The current voltage is converted into direct current voltage through the current-voltage conversion module and is output to the first AD conversion module; the secondary winding alternating current voltage is converted into equivalent direct current voltage through the AC / DC conversion module, and the equivalent direct current voltage is output to the second AD conversion module; and the data processing unit calculates to obtain alternating-current voltage or direct-current voltage of the current power supply, judges whether the current power supply is alternating-current power supply or direct-current power supply according to the current of the secondary winding, and outputs one of the alternating-current power supply and the direct-current power supply to the output interface. According to the invention, the AC network voltage is detected through the secondary winding, the current in the cable is detected through the Hall sensor and is converted into the DC voltage, the electrical isolation between the detection element and the high-voltage mutual inductor is realized, and the safety is improved.

Description

Technical Field

[0001] The invention relates to the technical field of overhead contact network voltage detection, and in particular to an overhead contact network AC and DC voltage detection device for a dual-power supply system train. Background Art

[0002] The dual-power supply train can run under DC1500V for subways and AC25kV for urban railways, realizing the through-operation of urban railways and subways, reducing the amount of tunnel excavation, reducing construction costs, reducing the number of transfers, and improving passenger commuting efficiency.

[0003] Dual-power supply trains must detect the current grid voltage of the power supply system in real time to ensure its safe and reliable operation. To this end, Chinese invention patent CN105510680B discloses an AC / DC grid voltage detection device, including a high-voltage transformer, a current limiting resistor, a DC isolation AC circuit, a DC isolation circuit, an AC sampling circuit and a DC sampling circuit. When the overhead power supply network line on the roof of the train provides an AC voltage, the primary side of the high-voltage transformer and the current limiting resistor divide the AC voltage, and the current limiting resistor acts as an AC grid voltage sampling resistor, and outputs the collected AC voltage signal to the AC sampling circuit through the DC isolation AC circuit, so that the CCU controls the dual-current or multi-current electric train to run under the AC grid voltage through the TCU; when the overhead power supply network line on the roof of the train provides a DC voltage, the primary side of the high-voltage transformer and the current limiting resistor divide the DC voltage, and the current limiting resistor acts as a DC grid voltage sampling resistor, and outputs the collected DC voltage signal to the DC sampling circuit through the DC isolation circuit, so that the CCU controls the dual-current or multi-current electric train to run under the DC grid voltage through the TCU.

[0004] This solution uses a resistor voltage divider to detect the grid voltage of the power supply system. Both the DC sampling circuit and the AC sampling circuit are connected to the primary side of the high-voltage transformer. There is no isolation design, which poses a major safety hazard. Summary of the invention

[0005] In view of the above-mentioned defects, the technical problem to be solved by the present invention is to provide an AC / DC network voltage detection device for a contact network of a dual-power supply train, so as to solve the potential safety hazard problem in the prior art.

[0006] To this end, the present application provides a contact network AC and DC network voltage detection device for dual-power supply trains, including a high-voltage transformer, the input end of the primary winding of which is connected to the contact network power supply line on the roof of the train, and the output end of the primary winding is connected to the rail through a current limiting resistor, and also includes:

[0007] A Hall sensor is arranged on the output cable of the primary winding, and is used to detect the current on the output cable of the primary winding in real time, and transmit the current to the current-voltage conversion module, convert it into a DC voltage, and output it to the first AD conversion module;

[0008] An AC / DC conversion module, whose input end is connected to the secondary winding of the high-voltage transformer, is used to convert the AC voltage of the secondary winding into an equivalent DC voltage in real time and output it to the second AD conversion module;

[0009] A data processing unit, whose input end is connected to the first AC / DC conversion module and the second AD conversion module, calculates the AC voltage or DC voltage of the current power supply, and judges whether the current power supply is AC power supply or DC power supply according to the current of the secondary winding, and outputs one to the output interface.

[0010] Based on the above technical solution, the AC grid voltage is detected through the secondary winding of the high-voltage transformer, and the current in the cable is detected by the Hall sensor on the output cable of the primary winding of the high-voltage transformer and converted into a DC voltage. Electrical isolation is achieved between the detection element and the high-voltage transformer, thereby improving safety.

[0011] In the above technical solution, preferably, a sampling resistor is connected in series to the secondary winding of the high-voltage transformer for collecting the current of the secondary winding, and the output end of the sampling resistor is connected to the data processing unit.

[0012] In the above technical solution, preferably, the output interface is an RS485 interface.

[0013] In the above technical solution, preferably, a communication module is further provided, connected to the AD conversion module, and used to output the AC voltage or DC voltage.

[0014] In the above technical solution, preferably, the communication module is a wired network card or a wireless network card.

[0015] It can be seen from the above technical solutions that the contact network AC and DC network voltage detection device for dual-power supply trains provided by the present invention solves the safety hazards of the prior art. Compared with the prior art, the present invention has the following beneficial effects:

[0016] The AC grid voltage is detected through the secondary winding of the high-voltage transformer, and the current in the cable is detected by the Hall sensor on the output cable of the primary winding of the high-voltage transformer and converted into a DC voltage. Electrical isolation is achieved between the detection element and the high-voltage transformer, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces and describes the drawings required for use in the embodiments of the present invention or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of the principle of a contact network AC and DC network voltage detection device for a dual-power supply train provided by the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0020] In order to ensure the safety and reliability of dual-power supply trains, the current grid voltage of the power supply system must be monitored in real time. The existing technology uses the resistance voltage division method for detection, in which both the DC and AC sampling circuits are directly connected to the primary winding of the high-voltage transformer, which poses a great safety risk.

[0021] This application scheme uses the secondary winding of the high-voltage transformer to detect the AC grid voltage. At the same time, a Hall sensor is installed on the output cable of the primary winding of the high-voltage transformer to detect the current in the cable in a non-contact manner and convert it into a DC voltage. In this scheme, electrical isolation is achieved between the detection element and the high-voltage transformer, which improves safety.

[0022] In order to provide a clearer explanation and description of the technical solution and implementation of the present invention, several preferred specific embodiments for implementing the technical solution of the present invention are introduced below.

[0023] It should be noted that the directional words such as "inside, outside", "front, back" and "left, right" in this article are expressed based on the product usage status. Obviously, the use of the corresponding directional words does not constitute a limitation on the protection scope of this scheme.

[0024] See also Figure 1 , Figure 1 A schematic diagram of a contact network AC and DC voltage detection device for a dual-power supply train provided by the present invention.

[0025] like Figure 1As shown, the present invention provides a contact network AC / DC network voltage detection device for dual-power supply trains, including a high-voltage transformer 10, a Hall sensor 20, an AC / DC conversion module 30, a current-voltage conversion module 40, a first AD conversion module 51, a second AD conversion module 52, a data processing unit 60 and an output interface.

[0026] The input end of the primary winding of the high-voltage transformer 10 is connected to the overhead power supply network line (AC / DC) on the roof of the train, and the output end is connected to the rail 70 through the current-limiting resistor R1.

[0027] The input end of the AC / DC conversion module 30 is connected to the secondary winding of the high-voltage transformer 10 , and is used to convert the AC voltage of the secondary winding of the high-voltage transformer 10 into an equivalent DC voltage in real time, and output it to the first AD conversion module 51 .

[0028] The Hall sensor 20 is arranged on the output cable of the primary winding of the high-voltage transformer 10 to detect the current on the output cable of the primary winding of the high-voltage transformer 10 in real time, and transmit the acquired current to the current-voltage conversion module 40 in real time, convert it into a DC voltage, and output it to the second AD conversion module 52.

[0029] The first AD conversion module 51 and the second AD conversion module 52 are used to convert the input analog signal into a digital signal and output it to the data processing unit 60. The data processing unit 60 calculates the currently detected AC voltage or DC voltage and selects one to output to an output interface, such as an RS485 interface, for processing by the back-end device.

[0030] Specifically, the data processing unit 60 is provided with a judgment module and a calculation module. The judgment module judges whether the current power supply is AC power supply or DC power supply according to the current value in the secondary winding of the high-voltage transformer 10, because if the current power supply is AC power supply, the current value in the secondary winding is large; if the current power supply is DC power supply, the current value in the secondary winding is very small, close to zero. When the data processing unit 60 judges that the current power supply is AC power supply, it outputs AC voltage; when the data processing unit 60 judges that the current power supply is DC power supply, it outputs DC voltage. The current in the secondary winding can be obtained by sampling resistance detection, that is, a sampling resistance is connected in series on the secondary winding of the high-voltage transformer 10, and the output end of the sampling resistance is connected to the judgment module in the data processing unit 60.

[0031] In the present application, the calculation method of the calculation module in the data processing unit 60 can be implemented in the following manner:

[0032] (1) AC voltage mode.

[0033] First, according to the output voltage U of the AC / DC conversion module x2(Secondary voltage of high voltage transformer), the primary voltage is calculated as U x1 =K T ×U x2 , K T is the transformation ratio of the high voltage transformer.

[0034] Then, according to the output current I2 of the Hall sensor, the primary current I1 of the high-voltage transformer is calculated to be I=K h ×I2, where K h Equivalent parameters of Hall sensor.

[0035] Then calculate the voltage on the current limiting resistor: U R =I1×R1=K h ×I2×R1.

[0036] Finally, the voltage of the overhead contact network on the rail is calculated:

[0037]

[0038] Where: K T , K h , R1 is related to the parameters of the selected component itself. Once selected, its value is basically fixed and known. x2 , I2 is the direct measurement value. The voltage of the contact network to the rail can be calculated by the above formula.

[0039] (2) DC voltage mode.

[0040] In DC power supply mode, the secondary side voltage U of the high voltage transformer x2 The measured value is almost zero. Assuming that the resistance of the primary winding of the high-voltage transformer is R T1 , then the DC voltage of the overhead contact network on the rail is:

[0041] U2=I1×(R T1 +R1)=K h ×I2×(R T1 +R1).

[0042] Among them, I1 is the primary side current of the high-voltage transformer.

[0043] Based on the description of the above specific embodiments, the contact network AC and DC network voltage detection device for dual-power supply trains provided by the present invention has the following advantages compared with the prior art:

[0044] First, the secondary winding of the high-voltage transformer is used to detect the AC grid voltage. At the same time, a Hall sensor is installed on the output cable of the primary winding of the high-voltage transformer to detect the current in the cable in a non-contact manner and convert it into a DC voltage. The detection element is electrically isolated from the contact network, which improves safety.

[0045] Second, the voltage difference between the contact network AC power supply (AC25kV) and DC power supply (DC1.5kV or DC0.75kV) is more than 2000 times. The existing technology uses the same voltage divider resistor for sampling and measurement, resulting in a wide range of voltage measurement. Therefore, the measurement accuracy is low. The present application scheme uses current conversion to obtain voltage, which is no longer affected by the AC / DC voltage difference, thereby improving the accuracy of voltage measurement.

[0046] Finally, it should be noted that the terms include, comprise or any other variation thereof as used herein are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the phrase "comprising a ..." does not exclude the presence of additional elements in the process, method, article or device comprising the element.

[0047] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone should be aware that any structural changes made under the inspiration of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention.

Claims

1. A contact network AC and DC network voltage detection device for dual-power supply trains, comprising a high-voltage transformer, the input end of the primary winding of which is connected to the contact network power supply line on the roof of the train, and the output end of the primary winding is connected to the rail through a current limiting resistor, characterized in that: Also includes: A Hall sensor is arranged on the output cable of the primary winding, and is used to detect the current on the output cable of the primary winding in real time, and transmit the current to the current-voltage conversion module, convert it into a DC voltage, and output it to the first AD conversion module; An AC / DC conversion module, whose input end is connected to the secondary winding of the high-voltage transformer, is used to convert the AC voltage of the secondary winding into an equivalent DC voltage in real time and output it to the second AD conversion module; A data processing unit, whose input end is connected to the first AC / DC conversion module and the second AD conversion module, calculates the AC voltage or DC voltage of the current power supply, and judges whether the current power supply is AC power supply or DC power supply according to the current of the secondary winding, and outputs one to the output interface.

2. The contact network AC and DC network voltage detection device for dual-power supply train according to claim 1, characterized in that: A sampling resistor is connected in series to the secondary winding of the high-voltage transformer for collecting the current of the secondary winding, and an output end of the sampling resistor is connected to the data processing unit.

3. The contact network AC and DC network voltage detection device for dual-power supply train according to claim 1, characterized in that: The output interface is an RS485 interface.

4. The contact network AC and DC network voltage detection device for dual-power supply train according to claim 1, characterized in that: A communication module is also provided, connected to the AD conversion module, for outputting the AC voltage or DC voltage.

5. The contact network AC and DC voltage detection device for dual-power supply train according to claim 4, characterized in that: The communication module is a wired network card or a wireless network card.

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