TW202036008A - Direct-current power supply leakage current detection device that comprises at least one leakage current detection module, a capacitor grounding module, and a malfunction analysis module - Google Patents

Abstract

The present invention provides a direct-current power supply leakage current detection device, which is used in combination with a direct-current power source and at least one load. The direct-current power source comprises a positive mother line that is electrically connected to a positive terminal of the load and a negative mother line that is electrically connected to a negative terminal of the load. The direct-current power supply leakage current detection device comprises at least one leakage current detection module, a capacitor grounding module, and a malfunction analysis module. The malfunction analysis module is configured to detect a potential difference between the load positive terminal and the load negative terminal exceeding a threshold. The malfunction analysis module controls a switch element that is arranged between the capacitor grounding module and a grounding terminal to be in an open-circuit condition and after a lapse of waiting time, controls the switch element to be in a short-circuit condition.

Description

DC power supply leakage current detection device

The invention relates to a DC power supply leakage current detection device, in particular to a DC power supply leakage current detection device with high sensitivity of leakage current detection.

In a DC power supply system, in order to provide a high-quality stable DC power supply, a non-grounded system is generally used, that is, a configuration where the output bus bar of the DC power supply is insulated from the ground. In this way, when a ground fault occurs in a certain part of the DC system, the operation of the DC system will not be affected because the whole system is independent of grounding. However, when two or more ground faults occur in the system to generate leakage current, it will cause a short circuit of the positive and negative bus bars, causing the entire DC system to fail. In addition, if a single-point grounded insulation degradation occurs in a non-grounded DC power system, leakage current should not be generated. However, because the circuit may have anti-interference capacitors and stray capacitance, this will provide a path for leakage current leakage.

In this regard, the conventional leakage detection methods include: balanced bridge detection method, unbalanced bridge detection method, AC signal source injection method, portable instrument leakage detection method, and capacitor ground leakage current detection method. Among them, the balanced electric bridge detection method uses the principle of bridge rectification. When the insulation between the positive and negative bus bars changes to the ground, the electric bridge loses balance and the alarm system can operate. However, the disadvantage of this method is that it is impossible to know whether the fault location is the positive bus or the negative bus, and when the positive and negative outputs of the DC power supply fail synchronously (the insulation resistance drops equally), the bridge will not be out of balance, but there is a detection problem. Blind spot. Although the unbalanced bridge can be applied to the situation where the positive and negative outputs are synchronously faulted, this method requires that the positive and negative ends of the DC output be connected to a test resistor to reduce the system's ground insulation capability. The AC signal source injection method is to inject a low-frequency AC voltage source into the positive and negative bus bars of the DC power system, and then use an AC sensor to detect the low-frequency AC signal of the branch, and calculate the resistance to ground according to the magnitude and phase angle of the AC current. However, recently, a large number of anti-interference capacitors are used in micro-electro-mechanical devices, which will increase the current value of the injected AC signal flowing through the anti-interference capacitors, and cause false alarms when leakage currents are discovered. The working principle of the portable instrument leakage inspection method is similar to that of the AC signal injection method. The portable instrument can be moved to each inspection position at will, and it is easier to find the fault grounding position of each branch. However, this type of product is currently limited by its DC Matching and anti-interference, so the detection accuracy is not high, and it is difficult to be adopted.

Finally, as in the announcement No. M411572, the DC power supply insulation fault detection device uses a capacitor to ground to provide a path for the return of the insulation fault leakage current. When the insulation resistance deteriorates, this method can successfully detect the fault leakage current. Specifically, when the insulation resistance deteriorates, the initial value of the leakage current is equal to the bus-to-ground voltage divided by the bus-to-ground insulation resistance, but as time passes, the charge of the bus-to-ground capacitance will reach a steady state balance, and the leakage current It will decay exponentially and will eventually approach zero. Therefore, if the capacitance grounding method is used for leakage current detection, the leakage current must be measured at the moment when the insulation resistance changes. However, the insulation degradation to the ground of the general DC system does not occur in a short time, but a rather slow process. During this period, the potential difference between the grounding capacitors will gradually decrease, resulting in a relatively small amount of fault leakage current. Measured by existing instruments.

Therefore, although the capacitive grounding method can overcome the shortcomings of most ground insulation degradation detection methods, it is limited by the sensitivity limit of the current detection device. The conventional capacitive grounding method will not provide the detection ability when the insulation resistance is slowly degraded Therefore, there is a need for improvement in the prior art.

The purpose of the present invention is to solve the problem that the prior art leakage current detection device has limited sensitivity and is difficult to detect when the leakage current is extremely small.

To achieve the above objective, the present invention provides a DC power supply leakage current detection device, which is used in conjunction with a DC power supply and at least one load. The DC power supply includes a positive bus electrically connected to the positive terminal of the load, and an electrical wire connection For the negative bus of the negative end of the load, the DC power supply leakage current detection device includes at least one leakage current detection module, a capacitor grounding module and a fault analysis module. The leakage current detection module is used for detecting whether there is a leakage current between the positive bus or the negative bus and the ground terminal. The capacitor grounding module includes a first capacitor connected in parallel to the positive bus, a first resistor connected in parallel to the first capacitor, a second capacitor connected in parallel to the negative bus, and a second capacitor connected in parallel to the second capacitor A resistor, and a switch element connected in series with the first capacitor, the first resistor, the second capacitor, and the second resistor, and the other end is connected in series with a ground terminal. The fault analysis module includes a voltage sensor electrically connected to the positive bus bar and the negative bus bar, a fault analyzer electrically connected to the voltage sensor and electrically connected to the leakage current detection module, wherein the The voltage sensor is configured to detect that the potential difference between the positive terminal of the load and the negative terminal of the load exceeds a threshold, the fault analysis module controls the switching element to be in an open state, and after a waiting time, controls the switching element to Short circuit state.

Further, the leakage current detection module includes a Hall element magnetically connected to the positive terminal of the load and the negative terminal of the load, a potential regulator electrically connected to the Hall element, and a comparison of the potential regulator electrically connected to the potential regulator The comparator outputs a leakage current detection signal to the fault analysis module.

Further, the fault analysis module includes a warning device electrically connected to the fault analyzer.

Further, the capacitive grounding module includes a current limiting resistor connected in series between the switching element and the ground terminal.

Further, when the leakage current exists, the leakage current detection module determines that the positive bus-to-ground fault or the negative bus-to-earth fault of the DC power source has occurred according to the current direction of the leakage current.

Therefore, the present invention has the following beneficial effects compared with the prior art: the present invention detects whether there is leakage current in the value flow system through the leakage current detection module, and uses the fault analysis module to detect the positive bus and the negative bus of the value flow power supply. Whether the potential difference exceeds a given threshold, judge whether the fault resistance in the system is likely to degrade slowly. If the above situation occurs, the fault analysis module will balance and reset the voltage on each capacitor in the capacitor grounding module by opening and closing the switch element, thereby increasing the amount of leakage current, so as to increase the leakage current detection module. The detection sensitivity overcomes the problem that the conventional DC leakage detection device is difficult to detect failures during the slow aging process.

Here are a few preferred implementation aspects of the technical features and operation methods of this application, which will be described in conjunction with the illustrations for review and reference. Furthermore, the figures in the present invention are not necessarily drawn according to the actual scale for the convenience of explanation, and the proportions in the figures are not used to limit the scope of the present invention.

Please refer to Figure 1 for the technology of the present invention. The present invention provides a DC power supply leakage current detection device 100, which is used with a DC power supply 200 and at least one load 300. The DC power supply 200 includes a positive bus 210 electrically connected to the positive terminal of the load 300, and an electrical wire Connecting to the negative bus 220 of the negative terminal of the load 300, the DC power supply leakage current detection device 100 includes at least one leakage current detection module 10, a capacitor grounding module 20, and a fault analysis module 30. In the present invention, the number of the load 300 can be more than one. Accordingly, each load 300 can be provided with a leakage current detection module 10 correspondingly. However, to simplify the description, only a single leakage current detection module 10 is used in the present invention. Module 10 indicates that it is stated first.

Specifically, the leakage current detection module 10 is used to detect whether there is a leakage current I _GN between the positive bus 210 or the negative bus 220 and the ground terminal. In this embodiment, the leakage current detection module 10 preferably includes a Hall element 11 magnetically connected to the positive terminal of the load 300 and the negative terminal of the load 300, and a potential regulator 12 electrically connected to the Hall element 11. And a comparator 13 electrically connected to the level regulator 12, the comparator 13 outputs a leakage current detection signal to the fault analysis module 30. In this way, the Hall element 11 can monitor the amount of current flowing into the load 300 by the positive bus 210 and the negative bus 220, and know whether the current flowing into and out of the load 300 is equal through electromagnetic induction, and then know whether There is leakage current. The Hall element 11 converts the result of the leakage current into a voltage signal and outputs it to the level regulator 12. Moreover, when the leakage current I _GN exists, the leakage current detection module 10 determines that the DC power supply 200 has a fault to the ground terminal of the positive bus 210 or a fault to the ground terminal of the negative bus 220 according to the current direction of the leakage current I _GN . In other words, when the leakage current I _GN exists, the Hall element 11 converts the leakage current I _GN into a voltage signal to the potential regulator 12, and the potential regulator 12 then provides a leakage current detection signal through the comparator 13 The fault analysis module 30 is used to make the DC power supply leakage current detection device 100 produce corresponding actions.

The capacitor module 20 includes a ground are connected in parallel to the positive bus line 210 of the first capacitor C _1, a capacitor C connected in parallel to the first resistor of _a first R & lt _1, a negative bus line 220 is connected in parallel to the second capacitance C ₂ of , A second resistor R ₂ connected in parallel to the second capacitor C ₂ , and a second resistor R ₂ connected in series to the first capacitor C ₁ , the first resistor R ₁ , the second capacitor C ₂ , the second resistor R ₂ and the other One end of the switching element S ₁ connected in series with the ground end. The switching element S ₁ can be realized by a relay, a transistor, a metal oxide semiconductor field effect transistor, etc., which can be turned on or off through an electrical signal. However, the above is only an example and is not intended to limit the patent application of the present invention. range. In this embodiment, the capacitive grounding module 20 includes a current limiting resistor R ₃ connected in series between the switching element S ₁ and the ground terminal to limit the leakage current I _GN .

The fault analysis module 30 includes a voltage sensor 31 electrically connected to the positive bus 210 and the negative bus 220, and a voltage sensor 31 electrically connected to the voltage sensor 31 and electrically connected to the fault of the leakage current detection module 10 The analyzer 32, wherein the voltage sensor 31 is configured to detect that the potential difference between the positive terminal of the load 300 and the negative terminal of the load 300 exceeds a threshold, and the fault analysis module 30 first controls the switching element S ₁ to In an open state, and after a waiting period of time, the switching element S ₁ is controlled to be in a short-circuit state, thereby maintaining a balance between the voltages of the positive bus 210 and the negative bus 220 to the ground. The aforementioned period of waiting time is determined based on the capacitance and parallel resistance of the capacitor grounding module 20, and the length of time at least needs to allow the first capacitor C ₁ and the second capacitor C ₂ to return to a steady state from the charging/discharging state. Preferably, the fault analysis module 30 includes a warning device 33 electrically connected to the fault analyzer 32 to inform the user whether the DC power supply 200 is faulty, and the fault location is the positive bus 210 to the ground or the negative bus 220 fault information such as ground. In other words, the voltage sensor 31 will detect the positive terminal potential of the load 300 connected to the positive bus 210 (that is, the voltage value of the positive bus 210 to ground) and the negative terminal potential of the load 300 connected to the negative bus 220 (also It is the range of the ratio between the voltage to ground of the negative bus 220), and the ratio can be set to the threshold. In the present invention, this range is | the voltage value of the positive bus 210 to ground/the pair of negative bus 220 Ground voltage value | in the range of 3/1 ~ 1/3, for example: when | the positive terminal potential of the load 300 / the negative terminal potential of the load 300 | = | the voltage value of the positive bus 210 to ground / the negative bus 220 voltage value to ground | <1/3, and the leakage current detection module 10 does not detect that there is a leakage current I _GN between the positive bus 210 or the negative bus 220, the fault analysis module 30 will First, control the switching element S _{1 to} be in an open state, that is, the capacitor grounding module 20 and the ground terminal are in an open state, and after a waiting period of time, the first capacitor C1 and the second capacitor C2 will be discharged. when the voltage of the capacitor C1 equal to the voltage of the second capacitor C2, representative of the load 300 of the positive bus 210 or the negative bus line 220 may not slow degradation of insulation resistance, and then controls the switching element S ₁ is at a short circuit state, so that the first A capacitor C1 and the second capacitor C2 return to the original rated voltage, thereby maintaining a balance between the positive bus 210 and the negative bus 220 voltage to ground, and improving the insulation fault detection of the DC power supply leakage current detection device 100 The ability.

The following describes the detection method of the present invention when the positive bus 210 is grounded to the ground fault, the negative bus 220 is grounded to the ground fault, and the insulation is slowly degraded. "Example One"

Please refer to Figure 2. In the present invention, when a ground fault occurs the DC power supply 200, and a ground terminal between the fault point will exhibit a fault resistance R _N. It should be noted that the fault resistance R _N not exist in a physical circuit, but as a simple expression of a schematic of a fault point when a fault occurs, it is at different fault state, the position of the fault resistance R _N will vary , I will state first.

(式1)

(式2) 其中，第一電壓V_{C1 (0)} 為該第一電容C₁ 的初始電壓，第二電壓V_C2(0) 為該第二電容C₂ 的初始電壓，該第一電壓V_C1(0) 加上該第二電壓V_C2(0) 等於該直流電源200之電壓U_dc 。再由克希荷夫電流定律(Kirchhoff`s Current Law, KCL) 可知第2圖之該洩漏電流I_GN 方程式為：

該洩漏電流I_GN 將分為兩路：第一電流I_C1(t) 與第二電流I_C2(t) 。該第一電流I_C1(t) 為該第一電容C₁ 儲能後放電而生，當該正母線210發生對地絕緣劣化時，儲存於該第一電容C₁ 之能量經該限流電阻R₃ 進行放電。之後，由於該第一電容C₁ 之儲能逐漸下降，該第一電容C₁ 之第一電壓V_C1 也將逐漸下滑。最後達到穩態平衡時，該第一電壓V_C1 將保持在較小的電壓，而該第一電容C₁ 亦不再釋放能量，該第一電容C₁ 所提供之該洩漏電流I_GN 將下降至零。另一條漏電路該第二電流I_C2(t) ，是由該直流電源200經該故障電阻R_N 流經該限流電阻R₃ ，再對該第二電容C₂ 進行儲能充電，再回至該直流電源200負端所構成之洩流路徑。由於該第二電容C₂ 之儲能增加，因此該第二電壓V_C2 將提高。最後達到穩態平衡時，該第二電壓V_C2 將較該第一電壓V_C1 更大。因此，當該正母線210發生絕緣劣化時，該第二電壓V_C2 將大於該第一電壓V_C1 。再者，該故障電流之大小主要受該故障電阻R_N 所影響，其次也受到該第一電容C₁ 、該第二電容C₂ 及該限流電阻R₃ 之電容電阻值所影響。因此，使用者可設計該第一電容C₁ 、該第二電容C₂ 及該限流電阻R₃ 之等參數來改變該故障電流大小及故障時間長短，以配合該漏電流檢測模組10之靈敏度調整，以期將該故障電流及故障持續時間壓制到最小。當系統達到穩態平衡時，該第一電容C₁ 不能再釋出電量，且該第二電容C₂ 無法再充入電量，故該洩漏電流I_GN 將不會再導通，達到防止電流洩漏之目的。 《實施例二》When the ground insulation degradation of the positive bus 210 occurs, the path of the leakage current I _GN is as shown in Figure 2. The leakage current I _GN flows from the positive bus 210 to the ground through the fault resistor R _N , and then from After the ground terminal flows through the current limiting resistor R ₃ , it returns to the DC power supply 200. The leakage current I _{GN is provided} by the first capacitor C ₁ and the second capacitor C ₂ through the conduction path, so that the leakage current detection module 10 can detect the fault current smoothly. According to Kirchhoff's Voltage Law (KVL), the leakage current I _GN equation in Figure 2 is:

(Formula 1)

(Equation 2) where the first voltage V _{C1 (0) is} the initial voltage of the first capacitor C ₁ , the second voltage V _{C2 (0) is} the initial voltage of the second capacitor C ₂ , and the first voltage V _{C1 (0)} plus the second voltage V _C2(0) is equal to the voltage U _{dc of} the DC power supply 200. From Kirchhoff's Current Law (KCL), we can see that the leakage current I _GN equation in Figure 2 is:

The leakage current I _GN will be divided into two paths: the first current I _C1(t) and the second current I _C2(t) . The first current I _{C1 (t)} of the first storage capacitor C ₁ after discharging for students, when the positive bus 210 to ground insulation degradation occurs, in stored energy of the first capacitor C ₁ through the current limiting resistor R ₃ discharges. After that, as the stored energy of the first capacitor C ₁ gradually decreases, the first voltage V _{C1 of} the first capacitor C ₁ will also gradually decrease. When the steady-state equilibrium is finally reached, the first voltage V _C1 will remain at a small voltage, and the first capacitor C ₁ will no longer release energy, and the leakage current I _GN provided by the first capacitor C ₁ will decrease. To zero. The second current I _{C2(t) of the} other leakage circuit is flowed from the DC power supply 200 through the fault resistor R _N through the current limiting resistor R ₃ , and then the second capacitor C ₂ is stored and charged, and then returned To the drain path formed by the negative terminal of the DC power supply 200. Since the stored energy of the second capacitor C ₂ increases, the second voltage V _C2 will increase. When the steady state equilibrium is finally reached, the second voltage V _C2 will be greater than the first voltage V _C1 . Therefore, when the insulation deterioration of the positive bus 210 occurs, the second voltage V _C2 will be greater than the first voltage V _C1 . Furthermore, the magnitude of the fault current is mainly affected by the fault resistance R _N , and secondly by the capacitance resistance of the first capacitor C ₁ , the second capacitor C ₂ and the current limiting resistor R ₃ . Therefore, the user can design the parameters of the first capacitor C ₁ , the second capacitor C ₂ and the current limiting resistor R ₃ to change the magnitude of the fault current and the length of the fault time to match the leakage current detection module 10 Sensitivity adjustment to suppress the fault current and fault duration to a minimum. When the system reaches a steady-state balance, the first capacitor C ₁ can no longer discharge electricity, and the second capacitor C ₂ can no longer be charged with electricity, so the leakage current I _GN will no longer be conducted to prevent current leakage purpose. "Example Two"

Please refer to Figure 3. When the insulation degradation of the negative bus 220 occurs to the ground, the path of the leakage current I _GN is as shown in FIG. 3. The fault current flows from the ground through the fault resistor R _N , and then flows to the capacitor grounding module 20 via the negative bus 220. At this time, the first voltage V _C1 will be greater than the second voltage V _C2 . And when the system reaches a steady state balance, the second capacitor C ₂ can no longer release electricity, and the first capacitor C ₁ can no longer be charged with electricity, which also achieves the purpose of preventing current leakage. "Example Three"

Considering that the insulation resistance degradation of the general system is not a rapid degradation, most of the cases are a process that occurs gradually over a relatively long period of time, and the degradation rate is extremely slow. When it slowly degrades to the fault threshold, the voltage to ground of the positive bus 210 or the negative bus 220 has dropped significantly, in other words, the voltages on the first capacitor C ₁ and the second capacitor C ₂ have also dropped significantly. Furthermore, since the current of the leakage current I _GN is the ratio of the capacitor voltage of the capacitor grounding module 20 to the fault resistance R _N , if the voltage on the first capacitor C ₁ and the second capacitor C ₂ is too low When the leakage current I _GN is large enough, the leakage current cannot be detected due to the limitation of the sensitivity of the existing current sensor, which causes the insulation fault detection to fail.

For example, suppose the output of the DC power supply 200 is a 100V non-grounded DC power supply 200 system, the sensitivity of the sensor for detecting leakage current is 1 mA, and the insulation resistance of the positive bus 210 and the negative bus 220 is set The initial value is 500 kΩ. When the fault resistance R _N drops below 50 kΩ, an alarm message will be issued. In this configuration, the ground voltage of the positive and negative bus 220 is 50V. When the fault resistance R _{N of} the positive bus 210 to the ground suddenly drops from 500 kΩ to 49 kΩ, the initial value of the leakage current I _GN is equal to 50V/49 kΩ=1.02 mA, because the leakage current threshold is set to 1 mA. The system will send out an alarm message normally. However, when the fault resistance R _{N of} the positive bus 210 drops slowly to 51 kΩ, the ground voltage of the positive bus 210 also drops to 9.26V. Subsequently, when the fault resistance R _N is further reduced from 51 kΩ to 49 kΩ, an insulation fault alarm should be issued. However, due to the moment of insulation failure, the leakage current I _GN is only 9.26 V/49 kΩ=0.19 mA. This leakage current value is far smaller than the minimum sensitivity of 1 mA, so it cannot be detected.

In this regard, the present invention can measure the voltage of the positive bus 210 and the negative bus 220 to the ground through the voltage sensor 31, when the ratio of the voltage of the positive bus 210 to the ground to the voltage of the negative bus 220 to the ground exceeds a certain range When the specific range of the present invention is that the ratio of the absolute value of the positive bus 210 to ground voltage to the negative bus 220 to ground voltage is between 1/3 and 3/1, the ratio depends on the tolerance of each DC , It is not limited here. In this embodiment, when the absolute value of the positive bus 210 to ground voltage and the negative bus 220 to ground voltage are less than 1/3, the leakage current detection module 10 does not detect If the leakage current I _GN exists, it can be known that the system has the possibility of slow insulation degradation. In this case, the failure analysis module the switching element S ₁ is disconnected (OFF), enabling the capacitor module 20 is grounded and the ground is disconnected, and in the first capacitance C _1, the second capacitor C ₂ After the voltage value reaches the steady state, that is, the first voltage V _c1 = the second voltage V _c2 , and then the switching element S _{1 is} closed (ON). At this time, because when the voltage of the first capacitor C ₁ and the second capacitor C ₂ rises to the original rated voltage, if the leakage current I _GN exists, its current value will increase with the increase in voltage, and the leakage current The current detection module 10 detects that the sensitivity of the leakage current detection module 10 is relatively improved.

In summary, the present invention uses the leakage current detection module 10 to detect whether there is a leakage current in the value flow system, and uses the fault analysis module 30 to detect whether the potential difference between the positive bus 210 and the negative bus 220 of the value flow power exceeds the supply voltage. Set the threshold to determine whether the fault resistance R _{N in the} system is likely to slowly deteriorate. If the above situation occurs, the fault analysis module 30 will balance and reset the voltage on each capacitor in the capacitor grounding module 20 through the switch element S ₁ , and then increase the leakage current I _GN to increase the relative current The detection sensitivity of the leakage current detection module 10 overcomes the problem that the conventional DC leakage detection device is difficult to detect failures during the slow aging process.

The content of the present invention has been described in detail above, but the above are only the preferred embodiments of the present invention, and should not be used to limit the scope of implementation of the present invention, that is, all equivalent changes and Modifications should still fall within the scope of the patent of the present invention.

100: DC power supply leakage current detection device 10: Leakage current detection module 11: Hall element 12: Potential regulator 13: Comparator 20: Capacitor grounding module C ₁ : First capacitor R ₁ : First resistor C ₂ : Second capacitor R ₂ : second resistor R ₃ : current limiting resistor S ₁ : switching element 30: fault analysis module 31: voltage sensor 32: fault analyzer 33: warning device 200: DC power supply 210: positive bus 220: negative bus 300: load V _c1 : first voltage V _c2 : second voltage I ₁ : first current I ₂ : second current I _GN : leakage current R _N : fault resistance

Figure 1: A schematic circuit diagram of the leakage current detection device for DC power supply of the present invention. Figure 2 is a schematic circuit diagram of the DC power supply leakage current detection device of the present invention when the insulation deterioration of the positive busbar occurs. Figure 3 is a schematic circuit diagram of the DC power supply leakage current detection device of the present invention when the negative bus insulation is deteriorated.

100: DC power supply leakage current detection device

10: Leakage current detection module

11: Hall element

12: Potential regulator

13: Comparator

20: Capacitor grounding module

C ₁ : first capacitor

R ₁ : first resistance

C ₂ : second capacitor

R ₂ : second resistance

R ₃ : current limiting resistor

S ₁ : Switching element

30: Failure Analysis Module

31: Voltage sensor

32: Fault Analyzer

33: Warning device

200: DC power supply

210: Positive bus

220: negative bus

300: load

Claims (10)

A DC power supply leakage current detection device is used in conjunction with a DC power supply and at least one load. The DC power supply includes a positive bus electrically connected to the positive end of the load, and a negative bus electrically connected to the negative end of the load, The DC power supply leakage current detection device includes: At least one leakage current detection module for detecting whether there is a leakage current between the positive bus or the negative bus and the ground terminal; A capacitor grounding module includes a first capacitor connected in parallel to the positive bus, a first resistor connected in parallel to the first capacitor, a second capacitor connected in parallel to the negative bus, and a first capacitor connected in parallel to the second capacitor Two resistors, and a switch element connected in series with the first capacitor, the first resistor, the second capacitor, and the second resistor, and the other end is connected in series with the ground; and A fault analysis module includes a voltage sensor electrically connected to the positive bus bar and the negative bus bar, a fault analyzer electrically connected to the voltage sensor and electrically connected to the leakage current detection module, wherein: The voltage sensor is configured to detect that the potential difference between the positive terminal of the load and the negative terminal of the load exceeds a threshold, then the fault analysis module controls the switching element to be in an open state, and after a period of waiting time, controls the switch The component is in a short-circuit state. The DC power supply leakage current detection device described in the first item of the scope of patent application, wherein the leakage current detection module includes a Hall element magnetically connected to the positive end of the load and the negative end of the load, and one electrically connected to the Hall element The potential regulator, and a comparator electrically connected to the potential regulator, the comparator outputs a leakage current detection signal to the fault analysis module. For the DC power supply leakage current detection device described in the first item of the scope of patent application, the fault analysis module includes a warning device electrically connected to the fault analyzer. For the DC power supply leakage current detection device described in item 1 of the scope of patent application, the capacitive grounding module includes a current limiting resistor connected in series between the switching element and the ground terminal. Such as the DC power supply leakage current detection device described in item 1 of the scope of patent application, wherein when the leakage current exists, the leakage current detection module determines that the DC power supply has a fault to the ground terminal of the positive bus bar according to the current direction of the leakage current Or the negative bus has a fault to the ground terminal. A DC power supply leakage current detection device is used in conjunction with a DC power supply and at least one load. The DC power supply includes a positive bus electrically connected to the positive end of the load, and a negative bus electrically connected to the negative end of the load, The DC power supply leakage current detection device includes: At least one leakage current detection module for detecting whether there is a leakage current between the positive bus and the ground terminal or the negative bus and the ground terminal; A capacitor grounding module includes a first capacitor connected in parallel to the positive bus, a first resistor connected in parallel to the first capacitor, a second capacitor connected in parallel to the negative bus, and a first capacitor connected in parallel to the second capacitor Two resistors and a switch element, wherein one end of the switch element is connected in series with the first capacitor, the first resistor, the second capacitor, and the second resistor, and the other end is electrically connected to the ground; and A fault analysis module includes a voltage sensor and a fault analyzer that is electrically connected to each other, wherein the voltage sensor is electrically connected to the positive bus and the negative bus, and the fault analyzer is electrically connected to the Leakage current detection module; Wherein, when the leakage current detection module detects that the positive bus has a leakage current, the leakage current of the positive bus will be discharged through the first capacitor of the capacitor grounding module; Wherein, when the leakage current detection module detects that the negative bus has a leakage current, the leakage current of the negative bus will be discharged through the second capacitor of the capacitor grounding module. Such as the DC power supply leakage current detection device described in item 6 of the scope of patent application, wherein the voltage sensor is configured to detect when the positive terminal potential of the load and the negative terminal potential of the load exceed the absolute value range of a ratio , The fault analysis module controls the switching element to be in an open state, and after a period of waiting time, controls the switching element to be in a short-circuit state. The DC power supply leakage current detection device described in item 7 of the scope of patent application, wherein the absolute value range of the ratio is |the positive terminal potential of the load/the negative terminal potential of the load| is between 1/3~3/1 . According to the DC power supply leakage current detection device described in item 6 of the scope of patent application, the leakage current detection module includes a Hall element magnetically connected to the positive end of the load and the negative end of the load, and an electrical connection to the Hall element The potential regulator, and a comparator electrically connected to the potential regulator, the comparator outputs a leakage current detection signal to the fault analysis module. According to the DC power supply leakage current detection device described in item 6 of the scope of patent application, the capacitive grounding module includes a current-limiting resistor connected in series between the switching element and the ground terminal.

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