Direct current leakage detection method, device, system, storage medium and program product

Abstract

The application relates to a direct current leakage detection method, device, system, storage medium and program product. The method comprises the following steps: determining a second voltage difference between a photocoupler component and a power supply voltage according to a first voltage difference between a negative electrode end and a ground end of a direct current bus; determining a corresponding protection voltage of a power consumption device according to a device attribute of the power consumption device and / or a power distribution level of the power consumption device in a direct current power grid system; detecting whether the power consumption device has leakage according to the second voltage difference and the protection voltage; and stopping power supply to the power consumption device if it is detected that the power consumption device has leakage. The method can improve the stability of the operation of the direct current power grid system.

Description

Technical Field

[0001] This application relates to the field of DC microgrid technology, and in particular to a DC leakage current detection method, device, system, storage medium, and program product. Background Technology

[0002] With the continuous development of DC power distribution networks, users are paying increasing attention to leakage problems in DC power grid systems. Generally, there are two situations in the power grid system that can cause the casing of electrical equipment to become electrified, thus causing leakage problems. One is that the lines in the power grid system are aging or the insulation of the lines is damaged, causing the casing of electrical equipment to become electrified; the other is that the power grid system often uses power electronic devices for power conversion, and the connection between the power source, the power electronic device, and the ground can also cause the casing of electrical equipment to become electrified.

[0003] Large leakage current problems in DC power grid systems can pose safety risks to users, making leakage current detection in DC distribution networks particularly important. Related technologies typically involve installing residual current devices (RCDs) in the DC power grid system. These RCDs disconnect all electrical equipment in the power grid system when a large leakage current problem occurs, ensuring the safe operation of the power grid system.

[0004] However, the aforementioned technologies can reduce the stability of DC power grid systems in some cases. Summary of the Invention

[0005] Therefore, it is necessary to provide a DC leakage current detection method, device, system, storage medium, and program product that can improve the stability of DC power grid system operation in response to the above-mentioned technical problems.

[0006] In a first aspect, this application provides a DC leakage current detection method, the method comprising:

[0007] The second voltage difference between the optocoupler assembly and the supply voltage is determined based on the first voltage difference between the negative terminal of the DC bus and the ground terminal.

[0008] Determine the protection voltage corresponding to the electrical equipment based on the equipment attributes and / or the power distribution level of the electrical equipment in the DC power grid system;

[0009] Based on the aforementioned second voltage difference and the aforementioned protection voltage, detect whether the aforementioned electrical equipment is leaking current.

[0010] If leakage is detected in the aforementioned electrical equipment, power supply to the equipment will be stopped.

[0011] In one embodiment, the detection of whether the electrical equipment has leakage current based on the second voltage difference and the protection voltage includes:

[0012] The second voltage difference is input to the negative input terminal of the voltage comparator in the DC power grid system, and the protection voltage is input to the positive input terminal of the voltage comparator.

[0013] The voltage comparator determines whether the second voltage difference is greater than the protection voltage, thus obtaining the detection result of whether the electrical equipment has leakage.

[0014] In one embodiment, the process of determining whether the second voltage difference is greater than the protection voltage using the voltage comparator to obtain a detection result indicating whether the electrical equipment has leakage current includes:

[0015] If the second voltage difference is greater than the protection voltage, then it is determined that the electrical equipment has a leakage current.

[0016] In one embodiment, determining the protection voltage corresponding to the electrical equipment based on the equipment attributes and / or the distribution level of the electrical equipment in the DC power grid system includes:

[0017] Based on the equipment attributes of the aforementioned electrical equipment, determine the first leakage protection current corresponding to the aforementioned electrical equipment;

[0018] Based on the power distribution level of the aforementioned electrical equipment in the DC power grid system, the target second leakage current corresponding to the level of the aforementioned electrical equipment is determined in a preset correspondence; the aforementioned correspondence includes the correspondence between different power distribution levels and different second leakage currents;

[0019] Based on the first leakage current and the target second leakage current, the protection voltage corresponding to the electrical equipment is determined.

[0020] In one embodiment, there is a positive correlation between the aforementioned power distribution level and the aforementioned second leakage protection current.

[0021] In one embodiment, the method further includes:

[0022] Output a prompt message to the user; the prompt message is used to prompt the user to check the above-mentioned electrical equipment, and / or to prompt the user whether the above-mentioned protection voltage needs to be adjusted.

[0023] Secondly, this application also provides a DC leakage current detection device, which includes:

[0024] The first determining module is used to determine the second voltage difference between the optocoupler component and the power supply voltage based on the first voltage difference between the negative terminal of the DC bus and the ground terminal.

[0025] The second determining module is used to determine the protection voltage corresponding to the electrical equipment based on the equipment attributes of the electrical equipment and / or the power distribution level of the electrical equipment in the DC power grid system.

[0026] The detection module is used to detect whether the electrical equipment has leakage current based on the second voltage difference and the protection voltage.

[0027] The stop module is used to stop supplying power to the electrical equipment if leakage is detected.

[0028] Thirdly, this application also provides a DC power grid system, which includes a DC bus, an optocoupler assembly, a controller, a voltage comparator, a power output switch, and electrical equipment.

[0029] The aforementioned optocoupler assembly includes a light-emitting diode and a phototransistor, wherein the light-emitting diode in the optocoupler assembly is connected in series between the negative terminal of the aforementioned DC bus and the ground terminal, and the collector terminal of the aforementioned phototransistor is connected to the negative input terminal of the aforementioned voltage comparator.

[0030] The controller is connected to the positive input terminal of the voltage comparator, the output terminal of the voltage comparator is connected to the power output switch, and the power output switch is connected to the electrical equipment.

[0031] The controller includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0032] Based on the first voltage difference between the negative terminal of the DC bus and the ground terminal, determine the second voltage difference between the optocoupler assembly and the supply voltage; based on the equipment attributes of the electrical equipment and / or the power distribution level of the electrical equipment in the DC power grid system, determine the protection voltage corresponding to the electrical equipment; based on the second voltage difference and the protection voltage, detect whether the electrical equipment has leakage current; if leakage current is detected in the electrical equipment, stop supplying power to the electrical equipment.

[0033] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the following steps:

[0034] Based on the first voltage difference between the negative terminal of the DC bus and the ground terminal, determine the second voltage difference between the optocoupler assembly and the supply voltage; based on the equipment attributes of the electrical equipment and / or the power distribution level of the electrical equipment in the DC power grid system, determine the protection voltage corresponding to the electrical equipment; based on the second voltage difference and the protection voltage, detect whether the electrical equipment has leakage current; if leakage current is detected in the electrical equipment, stop supplying power to the electrical equipment.

[0035] Fifthly, this application also provides a computer program product, which includes a computer program that, when executed by a processor, performs the following steps:

[0036] Based on the first voltage difference between the negative terminal of the DC bus and the ground terminal, determine the second voltage difference between the optocoupler assembly and the supply voltage; based on the equipment attributes of the electrical equipment and / or the power distribution level of the electrical equipment in the DC power grid system, determine the protection voltage corresponding to the electrical equipment; based on the second voltage difference and the protection voltage, detect whether the electrical equipment has leakage current; if leakage current is detected in the electrical equipment, stop supplying power to the electrical equipment.

[0037] The aforementioned DC leakage current detection method, device, system, storage medium, and program product determine a second voltage difference between the optocoupler component and the supply voltage based on a first voltage difference between the negative terminal of the DC bus and the ground terminal. It then determines the corresponding protection voltage for the electrical equipment based on its equipment attributes and / or its distribution level in the DC power grid system. Finally, it detects whether leakage current exists in the electrical equipment based on the second voltage difference and the protection voltage, and stops supplying power to the equipment when leakage current is detected. In this method, because a protection voltage can be set individually for each electrical equipment, and power supply is only stopped for that specific equipment when leakage current occurs, the normal operation of other equipment in the DC power grid system is not affected, resulting in high stability of the DC power grid system. Furthermore, since the protection voltage is set individually for each electrical equipment, leakage current detection can be targeted to that specific equipment, leading to more accurate leakage current detection results and more accurate control of the electrical equipment, further improving the stability of the DC power grid system. Attached Figure Description

[0038] Figure 1 This is a block diagram of a DC power grid system in one embodiment;

[0039] Figure 2 This is a flowchart illustrating a DC leakage current detection method in one embodiment;

[0040] Figure 3 This is a flowchart illustrating a DC leakage current detection method in another embodiment;

[0041] Figure 4 This is a flowchart illustrating a DC leakage current detection method in another embodiment;

[0042] Figure 5 This is a structural block diagram of a DC leakage current detection device in one embodiment. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0044] With the development of DC power distribution networks, dedicated residual current devices (RCDs) are generally not used at the end of DC power distribution systems, or the number of dedicated RCDs used is limited, and the specifications and models are even fewer. In this case, if the same type of RCD with fixed parameters is used throughout the DC power distribution network, fault ride-through can easily occur, causing all RCD protection devices in the entire distribution network to trip, thus reducing the stability of the DC power supply and distribution system. In the terminal distribution of DC power distribution networks, two situations can lead to the casing of electrical equipment becoming electrified: first, aging of the power grid lines or insulation damage can cause the casing of the electrical equipment to become electrified; second, in DC microgrids, most electrical equipment uses power electronic devices for power conversion, resulting in large high-frequency ripple on the DC bus. To increase the stability and anti-interference capability of electrical appliances, their input terminals often use Y-capacitor designs, with capacitors grounded from the positive and negative power buses. This easily generates a weak ground current, the magnitude of which is related to the magnitude and frequency of the high-frequency ripple. If the leakage current protection is designed to be a small fixed value (e.g., 10mA), false protection may occur. If the leakage current protection is designed to be a large fixed value (e.g., 80mA), fault ride-through is likely to occur, causing a fault in the entire DC microgrid and affecting the stability of the entire DC power grid system. Based on this, embodiments of this application provide a DC leakage current detection method, device, system, storage medium, and program product, which can solve this technical problem.

[0045] The DC leakage current detection method provided in this application embodiment can be applied to, for example... Figure 1 In the DC power grid system shown, Figure 1 Specifically, this is a schematic diagram of the DC power grid system. The DC power grid system includes a DC bus, optocouplers, a controller, a voltage comparator, a power output switch, and electrical equipment (not shown in the diagram). The optocouplers include a light-emitting diode (LED) and a phototransistor. The LED is connected in series between the negative terminal of the DC bus and the ground terminal. The collector terminal of the phototransistor is connected to the negative input terminal of the voltage comparator. The controller is connected to the positive input terminal of the voltage comparator, the output terminal of the voltage comparator is connected to the power output switch, and the power output switch is connected to the electrical equipment.

[0046] The DC bus can be a DC 375V DC bus, and AC / DC compatible electrical equipment, DC electrical equipment, energy storage equipment, and DC charging equipment can be directly connected to the DC bus; the DC bus can obtain power from the mains power grid through an AC / DC converter.

[0047] Optocoupler components (i.e.) Figure 1 OP1 in the diagram includes a light-emitting diode (LED) and a phototransistor. When the voltage difference across the LED reaches its forward voltage drop, the LED conducts and emits light of a specific wavelength through the generated current. This light can be received by the phototransistor. The positive terminal of the LED is connected to the ground terminal of the DC bus (i.e.,...). Figure 1 The protective ground (PE) of the LED is connected, and the negative terminal of the LED is connected to the negative terminal of the DC bus (i.e., the negative terminal of the LED). Figure 1 The LED is connected in series between the negative terminal of the DC bus and the ground terminal to detect the voltage difference between the protective ground and the negative terminal of the DC bus, thereby determining whether there is leakage in the casing of the electrical equipment.

[0048] This phototransistor, also known as a photodiode, conducts and generates current when the light intensity received from the LED reaches the threshold required to trigger its conduction. The emitter terminal of the phototransistor is connected to the supply voltage VCC. The current signal output from the collector terminal is converted into a voltage signal by a resistor amplifier and then connected to the negative input of a voltage comparator, simultaneously connecting to the analog-to-digital converter interface (ADC) of the controller. Figure 1 The ADC in the phototransistor is connected, and the collector of the phototransistor is grounded through resistor R2; the base of the phototransistor serves as a signal receiving window to receive the light emitted by the light-emitting diode.

[0049] The controller can be a controller composed of an MCU (Micro Controller Unit) chip, which may include an analog-to-digital converter interface (i.e.,...) Figure 1 (ADC in the middle) and digital-to-analog conversion interface (i.e. Figure 1 The MCU chip (DAC) is connected to the voltage comparator, with its ADC interface connected to the negative input of the voltage comparator and its DAC interface connected to the positive input of the voltage comparator. This is used to input the digital-to-analog converted protection voltage corresponding to the electrical equipment to the voltage comparator. This protection voltage can be user-defined or determined by the controller based on the equipment's hierarchy and attributes. Furthermore, the number of interfaces on the controller can be set according to actual needs and is not limited to a single value. Figure 1 The diagram shows 20 interfaces. Furthermore, both the voltage comparator and the controller can be connected to the supply voltage / power supply voltage VCC.

[0050] The voltage comparator takes two voltage inputs and outputs a high or low level. Its output can be connected to a power output switch to control its opening or closing. The power output switch is connected to the electrical equipment; its open / closed state is directly related to whether the equipment has power input. For example, when the power output switch is open, the DC bus can supply power to the equipment; when it is closed, the DC bus can stop supplying power, thus stopping the equipment from operating.

[0051] It should be noted that the execution subject of this application embodiment can be a DC power grid system or a controller in the system. The following will take the controller as an example to describe the solution in detail.

[0052] In one embodiment, such as Figure 2 As shown, a DC leakage current detection method is provided, which can be applied to... Figure 1 The method for the DC power grid system shown may include the following steps:

[0053] S202, determine the second voltage difference between the optocoupler component and the power supply voltage based on the first voltage difference between the negative terminal of the DC bus and the ground terminal.

[0054] In this step, the negative terminal of the DC bus (i.e. Figure 1 The 0V terminal in the circuit is connected to the ground terminal of the power supply port (i.e., the ground terminal). Figure 1 The first voltage difference between the protective earth (PE) terminal (i.e.) Figure 1 V in pe This is used to characterize whether the casing of an electrical device is live, i.e., whether the device is leaking current. Since this first voltage difference is not convenient to measure directly, it can be used to drive the optocoupler component to work, and the voltage difference can be detected by the operation of the optocoupler component. Here, the voltage difference measured by the optocoupler component refers to the voltage difference between the collector terminal of the phototransistor in the optocoupler component and the supply voltage terminal VCC, which can be denoted as the second voltage difference.

[0055] See Figure 1 As shown, the second voltage difference is related to the current value passing through the light-emitting diode in the optocoupler component. When the phototransistor in the optocoupler component is operating in amplification mode, the second voltage difference can be equivalent to detecting the current in the light-emitting diode and converting it into a voltage signal through an equivalent resistor. In summary, the second voltage difference can be quickly measured using a phototransistor. The optocoupler component has a relatively small time constant, making the measurement process for the second voltage difference very short, almost within microseconds, thereby improving the efficiency of detecting whether the casing of electrical equipment is energized.

[0056] Additionally, a resistor R1 can be connected in series between the negative terminal of the aforementioned DC bus and the ground terminal, before the LED, to reduce the impact of high current on the LED. Similarly, the aforementioned phototransistor can be grounded through a resistor R2, which also reduces the impact of high current on the phototransistor.

[0057] S204. Determine the protection voltage corresponding to the electrical equipment based on the equipment attributes and / or the distribution level of the electrical equipment in the DC power grid system.

[0058] Equipment attributes refer to the relevant electrical parameters of electrical equipment, such as rated current, rated voltage, and rated power. These attributes allow you to obtain the specific protective current or voltage of the equipment.

[0059] In a DC power grid system, there are typically multiple distribution levels from the service entrance to the end. For example, there could be three distribution levels from the service entrance to the end, in descending order: the first distribution level is the service entrance (e.g., the port leading to the user's premises), the second distribution level is for high-power electrical equipment, and the third distribution level is for low-power electrical equipment. The protective current or voltage corresponding to the electrical equipment at different distribution levels will also be different. These can be preset; for example, the protective current for the first distribution level can be set to 80mA, the second distribution level to 50mA, and the third distribution level to 10mA.

[0060] In this step, the user can pre-set the corresponding protective current for the electrical equipment based on its equipment attributes and / or the power distribution level where the equipment is located, and then convert this protective current into a protective voltage using the equivalent resistance of the human body. Alternatively, the protective current can be calculated based on the equipment attributes and / or the power distribution level where the equipment is located, as well as the load connected to the DC power grid, and then converted into a protective voltage using the equivalent resistance of the human body. Other methods are also possible, but are not specifically limited here. In short, the goal is to obtain the protective voltage corresponding to each electrical device.

[0061] S206, based on the second voltage difference and the protection voltage, detect whether the electrical equipment has leakage.

[0062] In this step, after obtaining the second voltage difference and the corresponding protection voltage of the electrical equipment, the electrical equipment can be directly compared with the second voltage difference to detect whether there is leakage. Alternatively, the second voltage difference and the protection voltage can be processed (e.g., differential processing) to detect whether there is leakage. The detection result of whether there is leakage in the electrical equipment can be obtained.

[0063] S208, if leakage is detected in the above-mentioned electrical equipment, the power supply to the above-mentioned electrical equipment shall be stopped.

[0064] In this step, if leakage current is detected in the electrical equipment through the second voltage difference and protection voltage, the power output switch connected to the front end of the electrical equipment can be directly disconnected to stop power supply to the equipment. This direct power outage via a single power switch provides a faster power cut-off, improving efficiency and preventing further safety incidents.

[0065] Of course, if the above-mentioned second voltage difference and protection voltage detect that there is no leakage in the electrical equipment, then the power supply to the electrical equipment can continue.

[0066] In the aforementioned DC leakage current detection method, a second voltage difference between the optocoupler and the supply voltage is determined based on a first voltage difference between the negative terminal of the DC bus and the ground terminal. The corresponding protection voltage for the electrical equipment is determined based on the equipment attributes and / or the distribution level in the DC power grid system. The method then detects whether leakage current exists in the electrical equipment based on the second voltage difference and the protection voltage, and stops supplying power to the equipment when leakage current is detected. This method allows for individual setting of protection voltages for each electrical device, and only stops supplying power to that specific device when leakage current occurs. This avoids affecting the normal operation of other devices in the DC power grid system, resulting in high stability of the DC power grid system. Furthermore, since the protection voltage is set individually for each device, leakage current detection can be targeted to that specific device, leading to more accurate leakage current detection results and more accurate control of the electrical equipment, further improving the stability of the DC power grid system.

[0067] The above embodiments mentioned that two voltages can be used to detect whether an electrical device has a leakage current. The following will explain in detail how to detect this using two voltages. Based on the above embodiments, see... Figure 3 As shown, the above S206 may include the following steps:

[0068] S302 inputs the second voltage difference to the negative input terminal of the voltage comparator in the DC power grid system, and inputs the protection voltage to the positive input terminal of the voltage comparator.

[0069] In this step, see Figure 1In the DC power grid system shown, the controller's front end is connected to a voltage comparator. The negative input terminal of this voltage comparator is connected to the collector terminal of a phototransistor to obtain the aforementioned second voltage difference. Additionally, the positive input terminal of this voltage comparator is connected to the controller's DAC interface, through which the protection voltage corresponding to the electrical equipment determined in S204 (i.e., the voltage difference between the two voltages) is input. Figure 1 V in ref ).

[0070] S304, the voltage comparator determines whether the second voltage difference is greater than the protection voltage, and obtains the detection result of whether the electrical equipment has leakage current.

[0071] In this step, after obtaining the second voltage difference and the corresponding protection voltage of the electrical equipment, the voltage comparator compares the second voltage difference with the protection voltage to determine whether the second voltage difference is greater than the protection voltage. This comparison can be done by directly comparing the magnitudes, by subtracting the second voltage difference from the protection voltage and comparing the difference to 0, by quotienting the second voltage difference from the protection voltage and comparing the quotient to 1, or by using other methods. In short, it can obtain a result indicating whether the second voltage difference is greater than the protection voltage.

[0072] In one possible implementation, optionally, if the second voltage difference is greater than the protection voltage, it is determined that the electrical equipment has leakage current. That is, the leakage current in the casing of the electrical equipment has reached a certain level, constituting a leakage current phenomenon. In this case, the voltage comparator can output a low level, which will turn off the power output switch connected to the downstream of the voltage comparator, thereby preventing power from being input to the electrical equipment downstream of the power output switch, i.e., stopping the power supply to the electrical equipment.

[0073] In another possible implementation, if the second voltage difference is less than or equal to the protection voltage, it is determined that the electrical equipment has no leakage current. In this case, the voltage comparator can output a high level, which will turn on / off the power output switch connected to the downstream of the voltage comparator, thereby supplying power to the electrical equipment downstream of the power output switch, i.e., supplying power to the electrical equipment.

[0074] In this embodiment, a voltage comparator is used to determine the relationship between the second voltage difference and the protection voltage to detect whether the electrical equipment has a leakage current. This voltage comparison process is relatively simple and intuitive, thus improving the efficiency of leakage current detection. Furthermore, the circuit structure is simple and low-cost, thereby saving on the cost of leakage current detection. Further, if the second voltage difference is greater than the protection voltage, it is determined that the electrical equipment has a leakage current. Therefore, voltage analysis can accurately determine the presence of leakage current in the electrical equipment, improving the accuracy of leakage current detection.

[0075] Currently, in DC power grid systems, to facilitate leakage current protection, a large current protection value is often configured for the entire DC power grid system to quickly achieve leakage current protection. However, this method is simplistic and crude, and it can lead to fault ride-through problems for some electrical devices with small leakage currents, thereby affecting the stability of the entire DC power grid system. To solve this problem, this application provides a scheme that allows for the individual setting of corresponding protection current / protection voltage for different electrical devices. The following is a detailed description of this scheme.

[0076] In another embodiment, see Figure 4 As shown, a schematic diagram is provided for determining the corresponding protection voltage of electrical equipment based on its equipment attributes and power distribution level. Based on the above embodiment, S204 may include the following steps:

[0077] S402, determine the first leakage protection current corresponding to the electrical equipment based on the equipment attributes of the electrical equipment.

[0078] In this step, when the electrical equipment is manufactured or used at the user's location, the manufacturer or user can set some corresponding power parameters for the electrical equipment, such as rated current, rated voltage, rated power, etc. Through these power parameters, the critical current value when leakage occurs can be calculated. Then, the critical current value is the corresponding protection current of the electrical equipment. Exceeding the critical current value is an unsafe current. This critical current value can be recorded here as the first leakage protection current.

[0079] S404, based on the power distribution level of the electrical equipment in the DC power grid system, determine the target second leakage current corresponding to the level of the electrical equipment in the preset correspondence; the correspondence includes the correspondence between different power distribution levels and different second leakage currents.

[0080] In this step, all electrical equipment in the DC power grid system / user's location can be pre-divided into power distribution levels, and a matching second leakage current can be set for each electrical equipment under each power distribution level. Then, the different power distribution levels and the different second leakage currents can be bound together to establish the correspondence between the two.

[0081] After obtaining the power distribution level of the electrical equipment in the DC power grid system, the power distribution level can be input into the established correspondence to obtain the matching second leakage protection current, which is denoted as the target second leakage protection current.

[0082] Optionally, there is a positive correlation between the aforementioned power distribution level and the aforementioned second leakage current. That is, the higher the power distribution level, the larger the corresponding second leakage current. Setting a positive correlation between the power distribution level and the second leakage current can prevent high-level power supply equipment from frequently shutting down due to system control, ensuring the normal operation of high-level power supply equipment and improving its operational stability. Simultaneously, the lower the power distribution level, the smaller the corresponding second leakage current. This allows for accurate control of low-level power supply equipment, achieving precise control of equipment in the DC power grid system.

[0083] S406, Based on the first leakage current and the target second leakage current, determine the protection voltage corresponding to the electrical equipment.

[0084] In this step, after obtaining the first leakage current and the target second leakage current, the first leakage current and the target second leakage current can be summed to obtain the leakage current sum value. The leakage current sum value is then multiplied by the equivalent resistance of the human body, and the obtained voltage value is the protection voltage corresponding to the electrical equipment.

[0085] In this embodiment, protective currents and voltages are specifically set for each electrical device based on its device attributes and the power distribution level it belongs to. This allows for targeted detection of leakage current in each device, resulting in more accurate leakage current detection results and thus more accurate control of the devices, thereby improving the stability of the DC power grid system. Furthermore, different protective currents / voltages can be set for different power distribution levels and device attributes, enabling different protective currents / voltages for different scenarios, thereby increasing the applicability and flexibility of this leakage current detection method.

[0086] Furthermore, to facilitate timely notification to the user in the event of a leakage problem, the following embodiment also provides a technical solution for notifying the user. In another embodiment, based on the above embodiments, if the electrical equipment has a leakage problem, the method may further include the following step A:

[0087] Step A: Output a prompt message to the user; the prompt message is used to prompt the user to check the above-mentioned electrical equipment, and / or to prompt the user whether the above-mentioned protection voltage needs to be adjusted.

[0088] In this step, LED lights can be used to output prompt messages to the user, for example... Figure 1An LED is connected in series with one of the output interfaces of the controller's MCU chip to alert the user. Alternatively, a buzzer or a voice announcer can be used to output the alert message; the specific method of outputting the alert message is not limited here.

[0089] This alert message is output when the electrical equipment is found to have a leakage current. It informs the user that leakage protection has been activated and prompts the user to check the electrical safety of the equipment. If the check reveals any unsafe electrical practices, the user can correct them.

[0090] Additionally, if the electrical equipment is found to be safe to use, the problem might lie in the inappropriate setting of its protective voltage / current. Users can adjust this setting to ensure it effectively monitors for leakage current. For example, if a device's protective current is pre-set to 10mA, and the system is confirmed to be safe after checking via notification messages, the current setting is likely too low. The current can be increased, for instance, to 12mA. Of course, in practice, it's also possible to adjust the current setting to a lower value.

[0091] In this embodiment, by outputting a prompt message to the user to remind them to check the electrical equipment or adjust the protection voltage, the user can be informed of the leakage problem of the electrical equipment in a timely and quick manner, thereby effectively reducing the risk of further safety accidents.

[0092] To facilitate further explanation of the embodiments of this application, the technical solution will be described below with reference to a specific embodiment. Based on the above embodiment, the method may include the following steps:

[0093] S1. Determine the second voltage difference between the optocoupler assembly and the power supply voltage based on the first voltage difference between the negative terminal of the DC bus and the ground terminal.

[0094] S2, determine the first leakage protection current corresponding to the electrical equipment based on the equipment attributes.

[0095] S3, based on the power distribution level of the electrical equipment in the DC power grid system, determine the target second leakage protection current corresponding to the level of the electrical equipment in the preset correspondence; the correspondence includes the correspondence between different power distribution levels and different second leakage protection currents.

[0096] S4. Determine the protection voltage corresponding to the electrical equipment based on the first leakage protection current and the target second leakage protection current.

[0097] S5 inputs the second voltage difference to the negative input terminal of the voltage comparator in the DC power grid system, and inputs the protection voltage to the positive input terminal of the voltage comparator.

[0098] S6 uses a voltage comparator to determine whether the second voltage difference is greater than the protection voltage, thus obtaining the detection result of whether the electrical equipment has leakage current.

[0099] S7. If the second voltage difference is greater than the protection voltage, it is determined that there is leakage in the electrical equipment.

[0100] S8, output a prompt message to the user; the prompt message is used to prompt the user to check the electrical equipment, and / or to prompt the user whether the protection voltage needs to be adjusted.

[0101] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0102] Based on the same inventive concept, this application also provides a DC leakage current detection device for implementing the DC leakage current detection method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more DC leakage current detection device embodiments provided below can be found in the limitations of the DC leakage current detection method described above, and will not be repeated here.

[0103] In one embodiment, such as Figure 5 As shown, a DC leakage current detection device is provided, comprising: a first determining module 11, a second determining module 12, a detection module 13, and a stop module 14, wherein:

[0104] The first determining module 11 is used to determine the second voltage difference between the optocoupler component and the power supply voltage based on the first voltage difference between the negative terminal of the DC bus and the ground terminal.

[0105] The second determining module 12 is used to determine the protection voltage corresponding to the electrical equipment based on the equipment attributes of the electrical equipment and / or the power distribution level of the electrical equipment in the DC power grid system.

[0106] Detection module 13 is used to detect whether the electrical equipment has leakage current based on the second voltage difference and the protection voltage.

[0107] The stop module 14 is used to stop supplying power to the electrical equipment if leakage is detected.

[0108] In another embodiment, another DC leakage current detection device is provided. Based on the above embodiments, the detection module 13 may include:

[0109] The input unit is used to input the second voltage difference to the negative input terminal of the voltage comparator in the DC power grid system, and to input the protection voltage to the positive input terminal of the voltage comparator.

[0110] The detection unit is used to determine whether the second voltage difference is greater than the protection voltage by the voltage comparator, and to obtain the detection result of whether the electrical equipment has leakage current.

[0111] Optionally, the detection unit is specifically used to determine that the electrical equipment has leakage current if the second voltage difference is greater than the protection voltage.

[0112] In another embodiment, another DC leakage current detection device is provided. Based on the above embodiments, the second determining module 12 may include:

[0113] The first determining unit is used to determine the first leakage protection current corresponding to the electrical equipment based on the equipment attributes of the electrical equipment.

[0114] The second determining unit is used to determine the target second leakage protection current corresponding to the level where the electrical equipment is located in the DC power grid system, based on the power distribution level of the electrical equipment in the DC power grid system and in a preset correspondence relationship; the correspondence relationship includes the correspondence between different power distribution levels and different second leakage protection currents.

[0115] The voltage determination unit is used to determine the protection voltage corresponding to the electrical equipment based on the first leakage protection current and the target second leakage protection current.

[0116] Optionally, there is a positive correlation between the above-mentioned power distribution level and the above-mentioned second leakage protection current.

[0117] In another embodiment, a different DC leakage current detection device is provided. Based on the above embodiments, the device may further include an output module.

[0118] This output module is used to output prompt messages to the user; the prompt messages are used to prompt the user to check the above-mentioned electrical equipment, and / or to prompt the user whether the above-mentioned protection voltage needs to be adjusted.

[0119] Each module in the aforementioned DC leakage current detection device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0120] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0121] Based on the first voltage difference between the negative terminal of the DC bus and the ground terminal, determine the second voltage difference between the optocoupler assembly and the supply voltage; based on the equipment attributes of the electrical equipment and / or the power distribution level of the electrical equipment in the DC power grid system, determine the protection voltage corresponding to the electrical equipment; based on the second voltage difference and the protection voltage, detect whether the electrical equipment has leakage current; if leakage current is detected in the electrical equipment, stop supplying power to the electrical equipment.

[0122] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0123] The second voltage difference is input to the negative input terminal of the voltage comparator in the DC power grid system, and the protection voltage is input to the positive input terminal of the voltage comparator; the voltage comparator determines whether the second voltage difference is greater than the protection voltage, and obtains the detection result of whether the electrical equipment has leakage current.

[0124] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0125] If the second voltage difference is greater than the protection voltage, then it is determined that the electrical equipment has a leakage current.

[0126] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0127] Based on the equipment attributes of the aforementioned electrical equipment, determine the first leakage current corresponding to the aforementioned electrical equipment; based on the distribution level of the aforementioned electrical equipment in the DC power grid system, determine the target second leakage current corresponding to the level where the aforementioned electrical equipment is located in a preset correspondence; the aforementioned correspondence includes the correspondence between different distribution levels and different second leakage currents; based on the aforementioned first leakage current and the aforementioned target second leakage current, determine the protection voltage corresponding to the aforementioned electrical equipment.

[0128] In one embodiment, there is a positive correlation between the aforementioned power distribution level and the aforementioned second leakage protection current.

[0129] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0130] Output a prompt message to the user; the prompt message is used to prompt the user to check the above-mentioned electrical equipment, and / or to prompt the user whether the above-mentioned protection voltage needs to be adjusted.

[0131] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0132] Based on the first voltage difference between the negative terminal of the DC bus and the ground terminal, determine the second voltage difference between the optocoupler assembly and the supply voltage; based on the equipment attributes of the electrical equipment and / or the power distribution level of the electrical equipment in the DC power grid system, determine the protection voltage corresponding to the electrical equipment; based on the second voltage difference and the protection voltage, detect whether the electrical equipment has leakage current; if leakage current is detected in the electrical equipment, stop supplying power to the electrical equipment.

[0133] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0134] The second voltage difference is input to the negative input terminal of the voltage comparator in the DC power grid system, and the protection voltage is input to the positive input terminal of the voltage comparator; the voltage comparator determines whether the second voltage difference is greater than the protection voltage, and obtains the detection result of whether the electrical equipment has leakage current.

[0135] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0136] If the second voltage difference is greater than the protection voltage, then it is determined that the electrical equipment has a leakage current.

[0137] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0138] Based on the equipment attributes of the aforementioned electrical equipment, determine the first leakage current corresponding to the aforementioned electrical equipment; based on the distribution level of the aforementioned electrical equipment in the DC power grid system, determine the target second leakage current corresponding to the level where the aforementioned electrical equipment is located in a preset correspondence; the aforementioned correspondence includes the correspondence between different distribution levels and different second leakage currents; based on the aforementioned first leakage current and the aforementioned target second leakage current, determine the protection voltage corresponding to the aforementioned electrical equipment.

[0139] In one embodiment, there is a positive correlation between the aforementioned power distribution level and the aforementioned second leakage protection current.

[0140] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0141] Output a prompt message to the user; the prompt message is used to prompt the user to check the above-mentioned electrical equipment, and / or to prompt the user whether the above-mentioned protection voltage needs to be adjusted.

[0142] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0143] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0144] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0145] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for detecting DC leakage current, characterized in that, The method is applied to a DC power grid system, and the method includes: The second voltage difference between the optocoupler assembly and the supply voltage is determined based on the first voltage difference between the negative terminal of the DC bus and the ground terminal. The protection voltage corresponding to the electrical equipment is determined based on the equipment attributes and the distribution level of the electrical equipment in the DC power grid system; the equipment attributes include the rated current, rated voltage, and rated power of the electrical equipment. Based on the second voltage difference and the protection voltage, detect whether the electrical equipment has leakage current; If leakage is detected in the electrical equipment, power supply to the electrical equipment shall be stopped; The step of determining the protection voltage corresponding to the electrical equipment based on the equipment attributes and the distribution level of the electrical equipment in the DC power grid system includes: Based on the equipment attributes of the electrical equipment, determine the first leakage protection current corresponding to the electrical equipment; Based on the power distribution level of the electrical equipment in the DC power grid system, the target second leakage current corresponding to the level of the electrical equipment is determined in a preset correspondence; the correspondence includes the correspondence between different power distribution levels and different second leakage currents. The first leakage current and the target second leakage current are summed to obtain the leakage current sum value. The leakage current sum value is then multiplied by the human body equivalent resistance to obtain the voltage value as the protection voltage corresponding to the electrical equipment.

2. The method according to claim 1, characterized in that, The step of detecting whether the electrical equipment has leakage current based on the second voltage difference and the protection voltage includes: The second voltage difference is input to the negative input terminal of the voltage comparator in the DC power grid system, and the protection voltage is input to the positive input terminal of the voltage comparator. The voltage comparator determines whether the second voltage difference is greater than the protection voltage, thereby obtaining the detection result of whether the electrical equipment has leakage current.

3. The method according to claim 2, characterized in that, The step of determining whether the second voltage difference is greater than the protection voltage through the voltage comparator to obtain the detection result of whether the electrical equipment has leakage current includes: If the second voltage difference is greater than the protection voltage, then it is determined that the electrical equipment has a leakage current.

4. The method according to claim 1, characterized in that, There is a positive correlation between the power distribution level and the second leakage protection current.

5. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Output a prompt message to the user; the prompt message is used to prompt the user to check the electrical equipment, and / or to prompt the user whether the protection voltage needs to be adjusted.

6. A DC leakage current detection device, characterized in that, The device includes: The first determining module is used to determine the second voltage difference between the optocoupler component and the power supply voltage based on the first voltage difference between the negative terminal of the DC bus and the ground terminal. The second determining module is used to determine the protection voltage corresponding to the electrical equipment based on the equipment attributes of the electrical equipment and the distribution level of the electrical equipment in the DC power grid system; the equipment attributes include the rated current, rated voltage, and rated power of the electrical equipment. The detection module is used to detect whether the electrical equipment has leakage current based on the second voltage difference and the protection voltage; A stop module is used to stop supplying power to the electrical equipment if leakage is detected in the electrical equipment. The step of determining the protection voltage corresponding to the electrical equipment based on the equipment attributes and the distribution level of the electrical equipment in the DC power grid system includes: Based on the equipment attributes of the electrical equipment, determine the first leakage protection current corresponding to the electrical equipment; Based on the power distribution level of the electrical equipment in the DC power grid system, the target second leakage current corresponding to the level of the electrical equipment is determined in a preset correspondence; the correspondence includes the correspondence between different power distribution levels and different second leakage currents. The first leakage current and the target second leakage current are summed to obtain the leakage current sum value. The leakage current sum value is then multiplied by the human body equivalent resistance to obtain the voltage value as the protection voltage corresponding to the electrical equipment.

7. A DC power grid system, characterized in that, This includes DC buses, optocoupler assemblies, controllers, voltage comparators, power output switches, and electrical equipment; The optocoupler assembly includes a light-emitting diode and a phototransistor, wherein the light-emitting diode is connected in series between the negative terminal of the DC bus and the ground terminal, and the collector terminal of the phototransistor is connected to the negative input terminal of the voltage comparator. The controller is connected to the positive input terminal of the voltage comparator, the output terminal of the voltage comparator is connected to the power output switch, and the power output switch is connected to the electrical equipment. The controller includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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