Electricity testing method for rail transit visual grounding device

Abstract

The invention discloses an electricity testing method for a rail transit visual grounding device. The electricity testing method comprises the following steps: inputting an electricity testing request signal; the first electricity testing interface loop and the second electricity testing interface loop which are arranged in a redundant mode are connected to a contact network; a catenary voltage signal is divided into two paths which are respectively input into an electricity testing interface loop 1 and an electricity testing interface loop 2, and the converted voltage signals are respectively input into an ADC analog-to-digital converter; calculating a channel voltage measurement value of the ADC analog-to-digital converter; based on the channel voltage measurement value, judging that the output of the high-voltage direct-current voltage transmitter is broken or has a fault or the overhead line system is not powered off, and disconnecting the electricity testing interface loop I and the electricity testing interface loop II; when the voltage measurement value U is larger than the electricity testing threshold voltage and smaller than 900V, it is judged that the contact network is powered off, and the residual voltage discharge loop is connected to the contact network for residual voltage discharge. The method can automatically identify the fault state of the high-voltage direct-current voltage transmitter and the performance reduction state of the high-voltage direct-current voltage transmitter.

Description

Technical Field

[0001] The invention belongs to the technical field of rail contact network electrical testing, and in particular relates to an electrical testing method for a rail transit visual grounding device. Background Art

[0002] Visual grounding devices are often used in DC1500V urban rail transit depots, parking lots and mainline stations. When the line is shut down for maintenance, they replace manual work and realize functions such as automatic power testing, automatic ground wire hanging and ground wire removal.

[0003] The existing visual grounding device test circuit often uses Figure 1 The circuit shown has two redundant power testing circuits, each of which includes a high-voltage DC fuse and a high-voltage DC voltage transmitter. A residual pressure relief circuit is connected in parallel behind the high-voltage DC fuse of one of the power testing circuits, including a high-voltage relay and a high-voltage power resistor.

[0004] This kind of electric detection circuit mainly has the following problems or shortcomings:

[0005] 1) The online cable of the power testing circuit is always connected to the contact network, which will inevitably reduce the insulation level of the contact network.

[0006] 2) The high-voltage DC voltage transmitter in the electrical testing circuit often uses DC05V or DC010V voltage signal output, and the fault status of the transmitter cannot be identified.

[0007] 3) The performance of the high-voltage DC voltage transmitter in the electrical testing circuit may degrade during long-term use. The existing grounding device fails to automatically identify the performance changes of the high-voltage DC voltage transmitter and provide early warning. Summary of the invention

[0008] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and provide an electrical testing method for a rail transit visual grounding device to solve the problems of reduced insulation level of the contact network and inability to automatically identify fault states and performance degradation states of high-voltage DC voltage transmitters.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A method for testing electricity for a rail transit visualized grounding device, comprising the following steps:

[0011] S1, input power test request signal;

[0012] S2, the visual grounding device receives the power test request signal and connects the redundant power test interface circuit 1 and the power test interface circuit 2 to the contact network;

[0013] S3, the overhead line voltage signal is divided into two paths, the two voltage signals are respectively input into the first and second circuits of the electrical test interface, and the converted voltage signals are respectively input into the ADC analog-to-digital converter;

[0014] S4, calculating the channel voltage measurement value of the ADC analog-to-digital converter according to the voltage signal input into the ADC analog-to-digital converter;

[0015] S5. Based on the channel voltage measurement value, determine that the output of the high-voltage DC voltage transmitter is disconnected or faulty, or the contact network is not powered off, and disconnect the first and second circuits of the electrical test interface;

[0016] S6. When the voltage measurement value U is greater than the test threshold voltage and less than 900V, it is judged that the contact network has been powered off, and the residual pressure discharge circuit is connected to the contact network to discharge the residual voltage.

[0017] Furthermore, the S2 specifically includes:

[0018] The visual grounding device receives the electrical test request signal, and the MCU controller U3 in the visual grounding device outputs a low-level signal through pin 50, driving the optoelectronic isolator U2, driving the switches of the high-voltage relay K2 and the high-voltage relay K3 to close, and then connecting the redundantly set electrical test interface circuits 1 and 2.

[0019] Furthermore, in the S3, a voltage signal is input into the electrical test interface circuit 1, and is input into the primary side of the high-voltage DC transmitter BT2 through the high-voltage fuse FU2 and the high-voltage relay K2 switch; the secondary side of the high-voltage DC transmitter BT2 isolates and outputs a 4-20mA current signal, which is converted into a 0.8-4V voltage signal on the sampling resistor R3 and input into the ADC analog-to-digital converter U4.

[0020] Furthermore, in the S3, a voltage signal is input into the second circuit of the electrical test interface, and is input into the primary side of the high-voltage DC transmitter BT1 through the high-voltage fuse FU3 and the high-voltage relay K3 switch; the secondary side of the high-voltage DC transmitter BT1 isolates and outputs a 4-20mA current signal, which is converted into a 0.8-4V voltage signal on the sampling resistor R2 and input into the ADC analog-to-digital converter U4.

[0021] Furthermore, in S4, the channel voltage measurement value of the ADC analog-to-digital converter is calculated, specifically:

[0022]

[0023] In the formula, U is the channel voltage measurement value; Data is the A / D sampling smoothing filter calculation value; Zero is the A / D sampling channel zero point; Full is the A / D sampling channel zero point; Range is the A / D sampling channel range.

[0024] Furthermore, the S5 specifically includes:

[0025] When the channel voltage measurement value U is less than -125V, it is judged that the high-voltage DC voltage transmitter BT1 or the high-voltage DC voltage transmitter BT2 has an output disconnection or fault, and then the closing operation of the visual grounding device is locked;

[0026] When the channel voltage measurement value U is greater than 900V, it is judged that the contact network is not powered off, and the visual grounding device closing operation is prohibited. The MCU controller outputs a high-level signal through pin 50, disconnects the optoelectronic isolator U2 drive signal, releases the high-voltage relay K3 and high-voltage relay K4 switches, and then disconnects the electrical test interface circuit 1 and the electrical test interface circuit 2, and exits the electrical test operation.

[0027] Furthermore, in S6, the residual pressure relief circuit is connected to the overhead line, which specifically includes:

[0028] When the channel voltage measurement value U is greater than the test threshold voltage and less than 900V, it is judged that the contact network has been powered off but there is residual voltage. The MCU controller outputs a low-level signal through pin 49 to drive the optoelectronic isolator U1, and then drives the high-voltage relay K1 switch to close, connecting the residual pressure discharge circuit to the contact network.

[0029] Furthermore, in S6, the residual voltage discharge circuit discharges the residual voltage of the contact network, specifically including:

[0030] The MCU controller starts the delay. During the delay time, the MCU controller continuously monitors the contact network voltage. When the monitored contact network voltage is lower than the voltage of the power test, the MCU controller outputs a high-level signal through pin 49, cancels the residual pressure discharge circuit, ends the power test, and allows the grounding device to close.

[0031] If the contact network voltage is still higher than the test threshold voltage before the delay time expires, the test fails and the grounding device closing operation is prohibited. The MCU controller outputs a high-level signal through pin 49, cancels the residual pressure discharge circuit, and ends the test.

[0032] The electric power testing method for a rail transit visualized grounding device provided by the present invention has the following beneficial effects:

[0033] 1. The access of the live detection circuit of the present invention does not affect the insulation level of the contact network: by connecting a high-voltage relay in series with the live detection circuit, the live detection circuit is only put into operation when the power test is needed, and is withdrawn after the power test is completed. During the non-power test period, the insulation level of the contact network is not affected.

[0034] 2. The present invention can automatically identify the fault state of the high-voltage DC voltage transmitter: the high-voltage DC voltage transmitter adopts 4-20mA signal output. When the output current is less than 4mA, it is judged that the output of the high-voltage DC voltage transmitter is disconnected, and the closing operation of the grounding device is locked.

[0035] 3. The present invention can automatically identify the performance degradation state of the high-voltage DC voltage transmitter: during the electricity test, the voltage detection values ​​of the two high-voltage DC voltage transmitters in the electricity test interface circuit 1 and the electricity test interface circuit 2 are compared in real time. When the difference between the two is greater than the set value, an alarm prompt is activated. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a circuit diagram of an existing electrical testing method for a visual grounding device in rail transit.

[0037] Figure 2 The present invention is a circuit diagram of a visualized grounding device for rail transit.

[0038] Figure 3 The process of the electric testing method for the visual grounding device of rail transit of the present invention is as follows Figure 1 .

[0039] Figure 4 This is a residual voltage discharge flow chart of the present invention.

[0040] Figure 5 The process of the electric testing method for the visual grounding device of rail transit of the present invention is as follows Figure 2 . DETAILED DESCRIPTION

[0041] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0042] Example 1

[0043] This embodiment provides a method for testing electricity for a visual grounding device for rail transit, which can effectively solve the problem of reduced insulation level of the contact network and inability to automatically identify the fault state and performance degradation state of the high-voltage DC voltage transmitter. Figure 3 , Figure 4and Figure 5 , which specifically includes the following steps:

[0044] Step S1, inputting an electrical inspection request signal;

[0045] When the subway line needs maintenance, the operator of the operating unit operates the "apply for power test" button of the visual grounding device.

[0046] Step S2, the visual grounding device receives the power test request signal, and connects the redundant power test interface loop 1 and the power test interface loop 2 to the contact network;

[0047] Specifically, after the visual grounding device controller detects the request signal, the MCU controller U3 outputs a low-level signal through pin 50 to drive the optoelectronic isolator U2, thereby driving the switches of the high-voltage relay K2 and the high-voltage relay K3 to close, and then connecting the redundantly set electrical test interface circuits 1 and 2.

[0048] Step S3, the overhead line voltage signal is divided into two paths, the two voltage signals are respectively input into the test interface circuit 1 and the test interface circuit 2, and the converted voltage signals are respectively input into the ADC analog-to-digital converter, which specifically includes the following contents:

[0049] After connecting redundant power test interface circuit 1 and power test interface circuit 2;

[0050] The contact network voltage signal is divided into two paths. One path of the contact network voltage signal is input into the second circuit of the electrical test interface, and then input into the primary side of the high-voltage DC transmitter BT1 through the high-voltage fuse FU3 and the high-voltage relay K3 switch; the secondary side of the high-voltage DC transmitter BT1 isolates and outputs a 4-20mA current signal, which is converted into a 0.8-4V voltage signal on the sampling resistor R2 and input into the ADC analog-to-digital converter U4.

[0051] Another contact network voltage signal is input into the electrical test interface circuit 1, and then input into the primary side of the high-voltage DC transmitter BT2 through the high-voltage fuse FU2 and the high-voltage relay K2 switch; the secondary side of the high-voltage DC transmitter BT2 isolates and outputs a 4-20mA current signal, which is converted into a 0.8-4V voltage signal on the sampling resistor R3 and input into the ADC analog-to-digital converter U4.

[0052] Step S4, calculating the channel voltage measurement value of the ADC analog-to-digital converter according to the voltage signal input into the ADC analog-to-digital converter, which specifically includes the following contents:

[0053] The ADC analog-to-digital converter U4 is connected to the MCU controller U5 through the SPI port. Under the control of the MCU, A / D sampling, conversion and calculation are performed to achieve contact network voltage measurement:

[0054] The MCU controller controls the ADC analog-to-digital converter through the SPI interface. The measured contact network voltage is a DC voltage with pulsating components. The response time of the high-voltage DC voltage sensor is ≤10ms. It is planned to sample a point every 5ms. The data buffer uses a FIFO with a length of 5. Every time a new data is sampled, the data in the buffer moves forward. The data in the front of the queue overflows and the new data is placed at the end of the queue. It is calculated every 5ms. The data in the buffer is defined as D1~D5. The specific calculation is as follows:

[0055] The calculated value for each A / D sampling is:

[0056]

[0057] The voltage measurement value U of each channel is:

[0058]

[0059] Among them, D1~D5 are A / D real-time sampling values; Data is the A / D sampling smoothing filter calculation value; Zero is the A / D sampling channel zero point; Full is the A / D sampling channel zero point; Range is the A / D sampling channel range.

[0060] Step S5: based on the channel voltage measurement value, determine whether the high-voltage DC voltage transmitter output is disconnected or faulty, or the contact network is not powered off, and disconnect the first and second circuits of the power test interface, which specifically includes the following contents:

[0061] When the calculated channel voltage measurement value U corresponding to the output signal of the high-voltage DC voltage transmitter is less than -125V (0V corresponds to 4mA on the secondary side of the high-voltage DC voltage transmitter and 0V on the primary side of the high-voltage DC voltage transmitter), it is judged that the output of the high-voltage DC voltage transmitter is disconnected or faulty, and the closing operation of the grounding device is locked.

[0062] When the channel voltage measurement value U calculated corresponding to the output signal of the high-voltage DC voltage transmitter is greater than 900V, it is judged that the contact network is not powered on, and the grounding device closing operation is prohibited. The MCU controller outputs a high-level signal through pin 50, disconnects the photoelectric isolator U2 drive signal, and releases the high-voltage relay K3 and high-voltage relay K4 switches, thereby disconnecting the redundantly set electrical test interface circuit 1 and electrical test interface circuit 2, and exits the electrical test operation.

[0063] Step S6: When the voltage measurement value U is greater than the test voltage threshold and less than 900V, it is determined that the contact network is powered off, and the residual voltage discharge circuit is connected to the contact network to discharge the residual voltage, which specifically includes the following contents:

[0064] When the channel voltage measurement value U calculated corresponding to the output signal of the high-voltage DC voltage transmitter is greater than the test threshold voltage (generally 600V by default) and less than 900V, it is judged that the contact network has been powered off, but there is residual voltage that needs to be discharged. The MCU controller outputs a low-level signal through pin 49 to drive the optoelectronic isolator U1, thereby driving the high-voltage relay K1 switch to close, connecting the residual pressure discharge circuit to the contact network to discharge the residual voltage of the contact network.

[0065] The MCU controller starts a delay. During the delay time, the MCU controller continuously monitors the contact network voltage. When the monitored contact network voltage is lower than the electrical test threshold voltage, the MCU controller outputs a high-level signal through pin 49, cancels the residual pressure discharge circuit, ends the electrical test, and allows the grounding device to close. If the monitored contact network voltage is still higher than the electrical test threshold voltage before the delay time expires, the electrical test fails, and the grounding device is prohibited from closing. The MCU controller outputs a high-level signal through pin 49, cancels the residual pressure discharge circuit, and ends the electrical test.

[0066] The visual grounding device of this embodiment refers to Figure 2 , which specifically include:

[0067] Residual pressure release circuit, live detection circuit and MCU controller;

[0068] Among them, the residual pressure relief circuit and the live detection circuit of this embodiment are arranged in parallel, the two ends of one side of the residual pressure relief circuit are respectively connected to the contact rail and the running rail, and the other side of the residual pressure relief circuit is connected to the MCU controller; the two ends of one side of the live detection circuit are respectively connected to the contact rail and the running rail, and the other side of the live detection circuit is connected to the MCU controller.

[0069] Specifically, as a preferred embodiment of this embodiment, the preferred configuration of the residual pressure relief circuit and the live detection circuit will be given below in this embodiment;

[0070] Residual pressure relief circuit;

[0071] The residual pressure discharge circuit of this embodiment includes a high-voltage DC fuse FU1, a high-voltage relay K1, a high-voltage power resistor R1, a drive resistor R4, a drive photoelectric isolator U1 and a freewheeling diode D1;

[0072] Among them, the high-voltage DC fuse FU1, the switch of the high-voltage relay K1 and the high-voltage power resistor R1 are connected in series in sequence and arranged between the contact rail and the running rail; the coil and the freewheeling diode D1 of the high-voltage relay K1 are connected in parallel to the driving photoelectric isolator U1; the driving photoelectric isolator U1 is connected to the MCU controller through the driving resistor R4.

[0073] In this embodiment, the preferred driving photoelectric isolator U1 is a TLP127 driving photoelectric isolator U1;

[0074] In the specific connection, the coil of the high-voltage relay K1 and the freewheeling diode D1 are connected in parallel to the 4th pin of the TLP127 driving optoelectronic isolator U1; the 2nd pin of the TLP127 driving optoelectronic isolator U1 is connected to the 49th pin of the MCU controller through the driving resistor R4.

[0075] Live detection circuit;

[0076] The live detection circuit includes an electrical test interface circuit 1 and an electrical test interface circuit 2.

[0077] Among them, the electrical test interface circuit 1 includes a high-voltage DC fuse FU2, a high-voltage relay K2, a high-voltage DC voltage transmitter BT2, a sampling resistor R3, an ADC analog-to-digital converter U4, a drive resistor R5, a drive photoelectric isolator U2 and a freewheeling diode D2;

[0078] One end of the high-voltage DC fuse FU2 is connected to the contact rail, and the other end of the high-voltage DC fuse FU2 is connected to the switch of the high-voltage relay K2 and the high-voltage DC voltage transmitter BT2 in sequence;

[0079] The coil of the high-voltage relay K2 and the freewheeling diode D2 are connected in parallel to the driving photoelectric isolator U2; the driving photoelectric isolator U2 is connected to the MCU controller through the driving resistor R5;

[0080] The high-voltage direct current voltage transmitter BT2 is connected to the ADC analog-to-digital converter U4 via a sampling resistor R3; the ADC analog-to-digital converter U4 is connected to the MCU controller via an SPI interface.

[0081] In this embodiment, the preferred driving photoelectric isolator U2 is a TLP127 driving photoelectric isolator U2; pin 4 of the TLP127 driving photoelectric isolator U2 is connected to the coil of the high-voltage relay K2, and pin 2 of the TLP127 driving photoelectric isolator U2 is connected to pin 50 of the MCU controller through a driving resistor R5.

[0082] In this embodiment, the high-voltage DC voltage transmitter BT2 is preferably a HY-SYB01A / 4 high-voltage DC voltage transmitter BT2, and the ADC analog-to-digital converter U4 is an AD7606BST analog-to-digital converter U4;

[0083] Pin 5 of the HY-SYB01A / 4 high-voltage DC voltage transmitter BT2 is connected to the running rail, and pin 6 of the HY-SYB01A / 4 high-voltage DC voltage transmitter BT2 is connected to the switch of the high-voltage relay K2; pins 3 and 4 of the HY-SYB01A / 4 high-voltage DC voltage transmitter BT2 are respectively connected to pins 51 and 52 of the AD7606BST analog-to-digital converter U4; and the sampling resistor R3 is set between pins 3 and 4 of the HY-SYB01A / 4 high-voltage DC voltage transmitter BT2.

[0084] The second circuit of the electrical test interface includes a high-voltage DC fuse FU3, a high-voltage relay K3, a high-voltage DC voltage transmitter BT1, a sampling resistor R2, an ADC analog-to-digital converter U4, a driving resistor R5, a driving photoelectric isolator U2, and a freewheeling diode D3;

[0085] One end of the high-voltage DC fuse FU3 is connected to the contact rail, and the other end of the high-voltage DC fuse FU3 is connected to the switch of the high-voltage relay K3 and the high-voltage DC voltage transmitter BT1 in sequence;

[0086] The coil of the high-voltage relay K3 and the freewheeling diode D3 are connected in parallel to the driving photoelectric isolator U2; the driving photoelectric isolator U2 is connected to the MCU controller through the driving resistor R5;

[0087] The high-voltage direct current voltage transmitter BT1 is connected to the ADC analog-to-digital converter U4 through a sampling resistor R2; the ADC analog-to-digital converter U4 is connected to the MCU controller through an SPI interface.

[0088] The driving photoelectric isolator U3 is a TLP127 driving photoelectric isolator; the 4th pin of the TLP127 driving photoelectric isolator is connected to the coil of the high-voltage relay K3, and the 2nd pin of the TLP127 driving photoelectric isolator is connected to the 50th pin of the MCU controller through the driving resistor R5.

[0089] The high-voltage DC voltage transmitter BT1 is HY-SYB01A / 4 high-voltage DC voltage transmitter BT1;

[0090] Pin 5 of HY-SYB01A / 4 high-voltage DC voltage transmitter BT1 is connected to the running rail and pin 5 of HY-SYB01A / 4 high-voltage DC voltage transmitter BT2 respectively;

[0091] Pin 6 of the HY-SYB01A / 4 high-voltage DC voltage transmitter BT1 is connected to the switch of the high-voltage relay K3; Pin 3 and Pin 4 of the HY-SYB01A / 4 high-voltage DC voltage transmitter BT1 are respectively connected to Pin 49 and Pin 50 of the AD7606BST analog-to-digital converter U4; and the sampling resistor R2 is set between Pin 3 and Pin 4 of the HY-SYB01A / 4 high-voltage DC voltage transmitter BT1.

[0092] The specific models or parameters of the electronic components related to this embodiment are as follows:

[0093] High voltage DC fuse FU1, FU2, FU3: DC1500V / 1A

[0094] High voltage DC fuses K1, K2, K3: HVR24-1A10

[0095] High voltage resistor R1: RI80 10W / 5M

[0096] High voltage DC transmitter BT1, BT2: HY-SYB01A / 4

[0097] Sampling resistors R3, R4: 200Ω

[0098] ADC analog-to-digital converter U4: AD7606BST

[0099] MCU controller U3: GD32F450ZKT6

[0100] R4, R5: 1KΩ

[0101] Driving opto-isolators U1, U2: TLP127

[0102] Freewheeling diodes D1, D2, D2: 1N4007

[0103] The present invention connects a normally open high-voltage relay in series behind the high-voltage DC fuse of each power testing branch. When power testing is required, the visual grounding device controller outputs a control signal to control the high-voltage relay contacts to close, so that the power testing circuit is connected to the contact network to complete the power testing work. After the power testing is completed, the visual grounding device controller cancels the control signal output, thereby disconnecting the high-voltage relay contacts and disconnecting the power testing circuit (live detection circuit) from the contact network.

[0104] The live detection circuit of the present invention adopts a high-voltage DC voltage transmitter with a DC4-20mA signal output. A 0V high-voltage signal input corresponds to a 4mA current output on the secondary side of the high-voltage DC voltage transmitter. Through threshold judgment, when the output current is less than 4mA, it is judged that there is an internal fault in the high-voltage DC voltage transmitter, and an alarm is issued to lock the closing operation of the grounding device.

[0105] The performance of the high-voltage DC voltage transmitter in the live detection circuit may deteriorate during long-term use, and the existing grounding device controller fails to automatically identify the performance changes of the high-voltage DC voltage transmitter. In response to this situation, the voltage detection values ​​of the test interface circuit one and the test interface circuit two are compared in real time, and a judgment threshold is set. When the difference between the two voltage detection values ​​is greater than the set threshold value, an early warning is issued to prompt the user to check and repair in time.

[0106] Although the specific implementation of the invention is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A method for testing electricity for a visual grounding device of rail transit, characterized in that: The following steps are involved: S1, input power test request signal; S2, the visual grounding device receives the power test request signal and connects the redundant power test interface circuit 1 and the power test interface circuit 2 to the contact network; S3, the overhead line voltage signal is divided into two paths, the two voltage signals are respectively input into the first and second circuits of the electric test interface, and the converted voltage signals are respectively input into the ADC analog-to-digital converter; S4, calculating the channel voltage measurement value of the ADC analog-to-digital converter according to the voltage signal input into the ADC analog-to-digital converter; S5. Based on the channel voltage measurement value, determine that the high-voltage DC voltage transmitter output is disconnected or faulty, or the contact network is not powered off, and disconnect the first and second circuits of the electrical test interface; S6. When the voltage measurement value U is greater than the test threshold voltage and less than 900V, it is judged that the contact network has been powered off, and the residual pressure discharge circuit is connected to the contact network to discharge the residual voltage.

2. The method for testing electricity for a visual grounding device for rail transit according to claim 1, characterized in that: The S2 specifically includes: The visual grounding device receives the electrical test request signal, and the MCU controller U3 in the visual grounding device outputs a low-level signal through pin 50, drives the optoelectronic isolator U2, drives the switches of the high-voltage relay K2 and the high-voltage relay K3 to close, and then connects the redundant electrical test interface circuit 1 and the electrical test interface circuit 2.

3. The method for testing electricity for a visual grounding device for rail transit according to claim 1, characterized in that: In the S3, a voltage signal is input into the first circuit of the electrical test interface, and then input into the primary side of the high-voltage DC transmitter BT2 through the high-voltage fuse FU2 and the high-voltage relay K2 switch; the secondary side of the high-voltage DC transmitter BT2 isolates and outputs a 4-20mA current signal, which is converted into a 0.8-4V voltage signal on the sampling resistor R3 and input into the ADC analog-to-digital converter U4.

4. The method for testing electricity for a visual grounding device for rail transit according to claim 1, characterized in that: In the S3, a voltage signal is input into the second circuit of the electrical test interface, and is input into the primary side of the high-voltage DC transmitter BT1 through the high-voltage fuse FU3 and the high-voltage relay K3 switch; the secondary side of the high-voltage DC transmitter BT1 isolates and outputs a 4-20mA current signal, which is converted into a 0.8-4V voltage signal on the sampling resistor R2 and input into the ADC analog-to-digital converter U4.

5. The method for testing electricity for a visual grounding device for rail transit according to claim 1, characterized in that: In S4, the channel voltage measurement value of the ADC analog-to-digital converter is calculated, specifically: In the formula, U is the channel voltage measurement value; Data is the A / D sampling smoothing filter calculation value; Zero is the A / D sampling channel zero point; Full is the A / D sampling channel zero point; Range is the A / D sampling channel range.

6. The method for testing electricity for a visual grounding device for rail transit according to claim 5, characterized in that: The S5 specifically includes: When the channel voltage measurement value U is less than -125V, it is judged that the high-voltage DC voltage transmitter BT1 or the high-voltage DC voltage transmitter BT2 has an output disconnection or fault, and then the closing operation of the visual grounding device is locked; When the channel voltage measurement value U is greater than 900V, it is judged that the contact network is not powered off, and the visual grounding device closing operation is prohibited. The MCU controller outputs a high-level signal through pin 50, disconnects the optoelectronic isolator U2 drive signal, releases the high-voltage relay K3 and high-voltage relay K4 switches, and then disconnects the electrical test interface circuit 1 and the electrical test interface circuit 2, and exits the electrical test operation.

7. The method for testing electricity for a visual grounding device for rail transit according to claim 1, characterized in that: In S6, the residual pressure relief circuit is connected to the overhead line, which specifically includes: When the channel voltage measurement value U is greater than the test threshold voltage and less than 900V, it is judged that the contact network has been powered off but there is residual voltage. The MCU controller outputs a low-level signal through pin 49 to drive the optoelectronic isolator U1, and then drives the high-voltage relay K1 switch to close, connecting the residual pressure discharge circuit to the contact network.

8. The method for testing electricity for a visual grounding device for rail transit according to claim 7, characterized in that: In S6, the residual pressure discharge circuit discharges the residual voltage of the contact network, specifically including: The MCU controller starts the delay. During the delay time, the MCU controller continuously monitors the contact network voltage. When the monitored contact network voltage is lower than the voltage of the power test, the MCU controller outputs a high-level signal through pin 49, cancels the residual pressure discharge circuit, ends the power test, and allows the grounding device to close. If the contact network voltage is still higher than the test threshold voltage before the delay time expires, the test fails and the grounding device closing operation is prohibited. The MCU controller outputs a high-level signal through pin 49, cancels the residual pressure discharge circuit, and ends the test.

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