Cable power supply detection device

Abstract

The invention provides a cable power supply detection device. The cable power supply detection device comprises a current sensor, a frequency reduction module, a sampling module and a control module. The current sensor is used for detecting high-frequency pulse current transmitted by the cable to generate first high-frequency voltage. The frequency reduction module comprises a high-pass filter circuit, a half-wave rectification circuit and a detection circuit. The high-pass filter circuit is used for performing high-pass filtering on the first high-frequency voltage and then outputting a second high-frequency voltage. The half-wave rectification circuit is used for carrying out half-wave rectification and amplification on the second high-frequency voltage so as to output pulsating voltage not smaller than 0. The detection circuit is used for detecting the pulsating voltage into a direct-current voltage. The sampling module is used for sampling DC voltage to output sampling voltage. The control module is used for outputting an alarm signal when the sampling voltage is greater than a preset safety threshold, and the alarm signal is used for indicating cable power supply instability. Therefore, the cable power supply detection device can automatically and efficiently detect the power supply stability condition of the cable and give an alarm, so that accidents can be effectively prevented.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a cable power supply detection device. Background Art

[0002] As the application of electricity becomes more and more widespread, the requirements for power supply quality in factories, enterprises and households are also constantly increasing. However, the quality of power supply does not only depend on the substation. The cables, conversion equipment, environment, power load and other factors used in the substation all affect the power supply voltage and frequency, resulting in reduced power supply stability. Among them, due to the high incidence of cable failures, the impact of cables on power supply stability is particularly prominent. For example, when there are weak insulation points in the cable insulation layer of high-voltage electrical equipment, the weak insulation points are prone to cause partial discharge, resulting in high-frequency current pulses. In the long run, it may also cause the insulation layer to be broken down, causing phase-to-phase short circuits, which will eventually lead to no electricity for factories and enterprises, resulting in huge losses. Therefore, it is necessary to detect the power supply stability of the cable. Summary of the invention

[0003] In view of this, the present application provides a cable power supply detection device, which can automatically detect the stability of the cable power supply and automatically alarm when the cable power supply is unstable, thereby avoiding accidents and cost losses. At the same time, it can improve the detection efficiency, reduce the detection cost, and can also be applied to various power usage scenarios, with a wide range of applications.

[0004] In order to achieve the above objectives, this application adopts the following technical solutions:

[0005] A cable power supply detection device comprises a current sensor, a frequency reduction module, a sampling module and a control module;

[0006] The current sensor is used to detect the high-frequency pulse current transmitted by the cable, thereby generating a first high-frequency voltage, the frequency of which is greater than a preset steady-state frequency;

[0007] The frequency reduction module includes a high-pass filter circuit, a half-wave rectifier circuit and a detection circuit, among which:

[0008] The high-pass filter circuit is connected to the current sensor, and is used to perform high-pass filtering on the first high-frequency voltage, thereby outputting a second high-frequency voltage;

[0009] The half-wave rectifier circuit is connected to the high-pass filter circuit and the detection circuit, and is used for performing half-wave rectification and amplification on the second high-frequency voltage, thereby outputting a pulsating voltage, and the pulsating voltage is not less than 0;

[0010] The detection circuit is used to detect the pulsating voltage into a DC voltage, wherein the DC voltage is greater than the pulsating voltage and reaches a preset steady-state frequency;

[0011] The sampling module is connected to the detection circuit, and the sampling module is used to sample the DC voltage, thereby outputting the sampled voltage;

[0012] The control module is connected to the sampling module. The control module is used to output an alarm signal when the sampling voltage is greater than a preset safety threshold. The alarm signal is used to indicate that the cable power supply is unstable.

[0013] In one embodiment, the half-wave rectifier circuit includes a voltage limiting amplifier, a feedback resistor and a voltage dividing resistor, wherein:

[0014] The non-inverting input terminal of the voltage limiting amplifier is used to connect to the high-pass filter circuit to access the second high-frequency voltage, the inverting input terminal of the voltage limiting amplifier is connected to the output terminal of the voltage limiting amplifier through a feedback resistor, the inverting input terminal of the voltage limiting amplifier is also grounded through a voltage dividing resistor, and the output terminal of the voltage limiting amplifier is connected to the detection circuit;

[0015] The first voltage limiting terminal of the voltage limiting amplifier is used to access the clamping voltage, and the clamping voltage is greater than 0; the second voltage limiting terminal of the voltage limiting amplifier is used to be grounded;

[0016] The voltage limiting amplifier is used to perform voltage limiting amplification on the second high frequency voltage according to the feedback resistor, the voltage dividing resistor, the clamping voltage connected to the first voltage limiting terminal and the zero voltage connected to the second voltage limiting terminal, thereby outputting a pulsating voltage.

[0017] In one embodiment, the half-wave rectifier circuit further includes a first coupling capacitor and a matching resistor, the in-phase input terminal of the voltage limiting amplifier is connected to the high-pass filter circuit via the first coupling capacitor, and the in-phase input terminal of the voltage limiting amplifier is grounded via the matching resistor.

[0018] In one embodiment, the voltage limiting amplifier is an OPA699 chip.

[0019] In one embodiment, the high-pass filter circuit includes a passive high-pass filter and a common-mode amplifier circuit, wherein:

[0020] The passive high-pass filter is connected to the current sensor and is used to perform high-pass filtering on the first high-frequency voltage;

[0021] The passive high-pass filter is also connected to the in-phase input terminal of the in-phase amplifier circuit, and the output terminal of the in-phase amplifier circuit is connected to the half-wave rectifier circuit. The in-phase amplifier circuit is used to perform in-phase amplification on the first high-frequency voltage after high-pass filtering, thereby outputting a second high-frequency voltage.

[0022] In one embodiment, the passive high-pass filter includes a first filter capacitor, a second filter capacitor, a first filter resistor and a second filter resistor, one end of the first filter capacitor is connected to the current sensor, the other end of the first filter capacitor is connected to one end of the second filter capacitor and the output end of the common-phase amplifier circuit through the first filter resistor, and the other end of the second filter capacitor is connected to the common-phase input end of the common-phase amplifier circuit and grounded through the second filter resistor.

[0023] In one embodiment, the detection circuit includes a second coupling capacitor, a first detection diode, a second detection diode, and an RC parallel circuit;

[0024] One end of the second coupling capacitor is connected to the output end of the half-wave rectifier circuit, and the other end of the second coupling capacitor is connected to the anode of the first detection diode, and the first detection diode and the second detection diode are connected in reverse parallel;

[0025] The RC parallel circuit is connected between the cathode of the first detection diode and the anode of the second detection diode. The RC parallel circuit is also connected to the sampling module and grounded. The RC parallel circuit is used to receive the pulsating voltage when the first detection diode is turned on, thereby outputting a DC voltage.

[0026] In one embodiment, the frequency of the DC voltage is within the sampling frequency range of the sampling module.

[0027] In one embodiment, the frequency of the DC voltage is in the range of 1 MHz to 50 MHz.

[0028] In one embodiment, the cable power supply detection device further includes:

[0029] An alarm module is connected to the control module, and the control module is used to output an alarm signal to the alarm module;

[0030] And / or, a communication module, connecting the control module and the terminal device, the communication module is used to transmit the alarm signal to the terminal device.

[0031] Compared with the prior art, this application has the following advantages:

[0032] 1. The cable power supply detection device of the present application can realize automatic detection and automatic alarm of the stability of cable power supply by setting a current sensor, a frequency reduction module, a sampling module and a control module, so that relevant personnel can take relevant measures in time when the cable power supply is unstable to prevent accidents in advance and reduce the cost losses caused by accidents. Compared with the current method of manual inspection by professionals, the cable power supply detection device of the present application can improve detection efficiency, reduce detection costs, and can also be applied to various power consumption scenarios, with a wide range of applications.

[0033] 2. The half-wave rectifier circuit of the present application has a half-wave rectifier function, so that the signal can be in the positive half cycle, thereby reducing the switching time of the PNP semiconductor transistor in the chip, thereby effectively improving the signal processing speed, and there is no need to set up a diode for voltage limiting. In addition, the half-wave rectifier circuit of the present application also has a gain amplification function, so it can solve the problem of signal transmission loss, improve signal quality, and there is no need to set up an amplification circuit separately. Therefore, the processing efficiency of the half-wave rectifier circuit of the present application can be improved, the component cost can be reduced, and the occupied space of the half-wave rectifier circuit can be reduced.

[0034] 3. The detection circuit of the present application can reduce the voltage frequency to a preset steady-state frequency. Based on such a design, on the one hand, the sampling frequency of the post-stage sampling module can be reduced, thereby reducing the cost of the sampling module; on the other hand, the recovery time of the detection circuit can be reduced, so that the detection circuit can better perform the detection function, thereby improving the output quality.

[0035] 4. In the frequency reduction module of the present application, the high-pass filter circuit can filter out noise and effectively reduce the interference of noise on the subsequent circuit. The half-wave rectifier circuit can have a higher processing speed and output quality. The detection circuit can reduce the output frequency to a preset steady-state frequency (such as 1MHz to 50MHz). Therefore, the combination of the high-pass filter circuit, the half-wave rectifier circuit and the detection circuit can fully improve the detection efficiency and accuracy of the cable power supply detection device. If the frequency reduction module does not use a half-wave rectifier circuit, does not have voltage limiting and amplification processing, and is not connected to the detection circuit, then when the cable power supply detection device is working, it will be easy for the operational amplifier to be saturated and cut off in some frequency bands (such as 1MHz to 20MHz), and the signal will also carry a lot of noise, which will easily affect the detection effect and cause false alarms. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0037] Figure 1 It is a schematic diagram of a cable power supply detection device provided in an embodiment of the present application.

[0038] Figure 2 yes Figure 1 A circuit diagram of the frequency reduction module in FIG.

[0039] Figure 3 This is another schematic diagram of the cable power supply detection device provided in an embodiment of the present application.

[0040] Figure 4 yes Figure 3 A circuit block diagram of a cable power supply detection device is shown.

[0041] Figure 5 yes Figure 1 An input and output waveform diagram of the mid-frequency reduction module.

[0042] Figure 6 yes Figure 1 Schematic diagram of an output waveform of the sampling module.

[0043] Main component symbols

[0044] Cable power supply detection device 100

[0045] Current sensor 1

[0046] Down-conversion module 2

[0047] High pass filter circuit 21

[0048] Passive High Pass Filter 211

[0049] Common-mode amplifier circuit 212

[0050] Half-wave rectifier circuit 22

[0051] Detection circuit 23

[0052] Sampling module 3

[0053] Control module 4

[0054] Alarm module 5

[0055] Communication module 6

[0056] Cable 200

[0057] Terminal device 300

[0058] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0060] In the description of the present application, it should be understood that the terms "first" and "second" etc. are used to distinguish different objects, rather than to describe a specific order. The terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. The terms "including" and any variations thereof are intended to cover non-exclusive inclusions.

[0061] As the application of electricity becomes more and more extensive, the requirements for power supply quality in factories, enterprises and households are also constantly increasing. However, the quality of power supply does not only depend on the substation. The cables, conversion equipment, environment, power load and other factors used in the substation all affect the power supply voltage and frequency, resulting in reduced power supply stability. Among them, due to the high incidence of cable failures, the impact of cables on power supply stability is particularly prominent. For example, when there is a weak insulation in the insulation layer of the cable of high-voltage electrical equipment (that is, the location where the insulation layer is aged or damaged), the weak insulation may accumulate charge and cause local electric field stress concentration, causing local discharge, and in this process, high-frequency current pulses will be generated. High-frequency current pulses often generate high-frequency energy signals at weak insulation. Therefore, in the long run, they may also cause the insulation layer to be broken down, causing phase-to-phase short circuits, which will eventually lead to factories and enterprises without electricity, resulting in huge losses. Therefore, it is necessary to detect the power supply stability of the cable.

[0062] At present, partial discharge and short circuit accidents of cables are mainly discovered through inspections by professionals. However, this method is inefficient and immediacy-free, and requires high labor costs and professional testing equipment costs, and is not very applicable on site.

[0063] Therefore, the embodiment of the present application provides a cable power supply detection device, which can automatically, instantly and at low cost detect whether the power transmitted by the cable is stable, and can promptly alarm when the cable power supply is unstable, thereby effectively preventing accidents. Moreover, the cable power supply detection device of the embodiment of the present application can be applied to various power usage scenarios, such as medium voltage, high voltage, and ultra-high voltage scenarios, such as substations in the power system, factories, enterprises, and households that need electricity, so it has a wide range of applications.

[0064] The following is an introduction to the cable power supply detection device according to an embodiment of the present application.

[0065] See also Figure 1 The cable power supply detection device 100 includes a current sensor 1 and a frequency reduction module 2 .

[0066] The current sensor 1 is disposed on the cable 200. When the cable 200 has partial discharge, resulting in high-frequency current pulses, the current sensor 1 can be used to detect the high-frequency pulse current in the current transmitted by the cable 200, thereby generating a corresponding first high-frequency voltage Vhf1.

[0067] The type of the current sensor 1 is not limited, as long as the current sensor 1 can achieve the corresponding function. For example, in some embodiments, the current sensor 1 can be a high frequency current transformer (HFCT). The HFCT can be installed in three phases (corresponding to Figure 1 The grounding connector or grounding wire of any phase cable 200 (R, S, T phases in the circuit). When a high-frequency pulse current is generated in any phase cable 200 due to the presence of a local discharge phenomenon, the high-frequency pulse current can be coupled to the HFCT. Since the HFCT itself has an equivalent impedance, the high-frequency pulse current can be converted into a corresponding first high-frequency voltage. The frequencies of the high-frequency pulse current and the first high-frequency voltage Vhf1 are both greater than the preset steady-state frequency. The size of the preset steady-state frequency can be set accordingly according to actual conditions, and is not specifically limited here. For example, the preset steady-state frequency can be 50 MHz, or for example, it can be any other frequency value or any frequency range between 1 MHz and 50 MHz.

[0068] The current sensor 1 is also connected to the frequency reduction module 2, so the first high-frequency voltage Vhf1 can be output to the frequency reduction module 2. The frequency reduction module 2 can perform frequency reduction and amplification processing on the first high-frequency voltage Vhf1, thereby outputting a DC voltage Vdc.

[0069] Please also read Figure 2 The frequency reduction module 2 includes a high-pass filter circuit 21, a half-wave rectifier circuit 22 and a detection circuit 23.

[0070] The high-pass filter circuit 21 adopts a high-pass active filter circuit, which may specifically include a passive high-pass filter 211 and a common-mode amplifier circuit 212. The passive high-pass filter 211 may be an RC high-pass filter.

[0071] Specifically, if Figure 2 As shown, the passive high-pass filter 211 may include a first filter capacitor, a second filter capacitor, a first filter resistor, and a second filter resistor. The in-phase amplifier circuit 212 may include an operational amplifier A1, a feedback resistor, a voltage divider resistor, and a first bypass capacitor.

[0072] It can be understood that the first filter capacitor, the second filter capacitor, and the first bypass capacitor can all be a capacitor element, or they can be composed of multiple capacitor elements connected in series, in parallel, or in series and in parallel. Similarly, the first filter resistor, the second filter resistor, the feedback resistor, and the voltage-dividing resistor can all be a resistor element, or they can be composed of multiple resistor elements connected in series, in parallel, or in series and in parallel. It is not limited here. For ease of description, the embodiment of the present application is shown as an example in which the first filter capacitor is capacitor C1, the second filter capacitor is capacitor C2, the first bypass capacitor is formed by capacitor C3 and capacitor C4 in parallel, the first filter resistor is resistor R1, the second filter resistor is resistor R2, the feedback resistor is resistor Rf1, and the voltage-dividing resistor is resistor R3. Among them, for the convenience of distinguishing from the half-wave rectifier circuit 22, the feedback resistor Rf1 in the in-phase amplifier circuit 212 is referred to as the first feedback resistor, and the voltage-dividing resistor R3 in the in-phase amplifier circuit 212 is referred to as the first voltage-dividing resistor.

[0073] One end of the first filter capacitor C1 is connected to the current sensor 1, the other end of the first filter capacitor C1 is connected to one end of the second filter capacitor C2 and connected to the output end of the operational amplifier A1 through the first filter resistor R1, and the other end of the second filter capacitor C2 is connected to the non-inverting input end of the operational amplifier A1 and grounded through the second filter resistor R2. The inverting input end of the operational amplifier A1 is connected to the output end of the operational amplifier A1 through the first feedback resistor Rf1, and the inverting input end of the operational amplifier A1 is also grounded through the first voltage divider resistor R3. The positive power supply end of the operational amplifier A1 is used to connect to the positive power supply voltage +Vs1, and the negative power supply end of the operational amplifier A1 is used to connect to the negative power supply voltage -Vs1. The positive power supply end and the negative power supply end of the operational amplifier A1 are also grounded through the first bypass capacitor to stabilize the connected power supply voltage.

[0074] Based on such a design, the first filter capacitor C1, the first filter resistor R1, the second filter capacitor C2 and the second filter resistor R2 together constitute a second-order RC high-pass filter, wherein the first filter capacitor C1 and the first filter resistor R1 constitute a first-stage circuit, and the second filter capacitor C2 and the second filter resistor R2 constitute a second-stage circuit. The transfer function H(s) of the second-order RC high-pass filter is as follows:

[0075]

[0076] Here, s is a complex parameter.

[0077] According to H(s), the cutoff frequency f of the second-order RC high-pass filter is:

[0078]

[0079] Obviously, the passive high-pass filter 211 can be used to filter out interference signals with frequencies lower than the cut-off frequency f in the first high-frequency voltage Vhf1, and allow signals with frequencies not lower than the cut-off frequency f to pass. That is, the passive high-pass filter 211 can be used to perform high-pass filtering on the first high-frequency voltage Vhf1. The cut-off frequency f is substantially equal to the preset steady-state frequency.

[0080] The in-phase amplifier circuit 212 can be used to perform in-phase amplification on the first high-frequency voltage Vhf1 after high-pass filtering, thereby outputting a second high-frequency voltage Vhf2, wherein the amplification factor (ie, gain) A'=1+Rf1 / R3.

[0081] It can also be seen from the above that the passband of the high-pass filter circuit 21 depends on the passive high-pass filter 211, and the gain depends on the first feedback resistor Rf1 and the first voltage-dividing resistor R3 of the in-phase amplifier circuit 212. Therefore, in actual implementation, the model parameters of each component in the passive high-pass filter 211 and the in-phase amplifier circuit 212 can be determined according to actual needs.

[0082] For example, the operational amplifier A1 can be an operational amplifier with high conversion rate and high gain-bandwidth product, such as an operational amplifier chip of model LT1363, whose conversion rate can reach 1000V / μs and gain-bandwidth product can reach 70MHz. In this way, it is beneficial to process the first high-frequency voltage Vhf1 in real time, thereby facilitating the signal processing of the subsequent circuit and module, thereby improving the real-time performance of the cable power supply stability detection.

[0083] To match the LT1363 chip, in the first bypass capacitor, the capacitor C3 can be 10uF, and the capacitor C4 can be 0.1uF. For further example, when the frequency of the first high-frequency voltage Vhf1 is greater than the preset steady-state frequency of 50MHz, the first filter capacitor C1 and the second filter capacitor C2 can be 33pF, the first filter resistor R1 can be 7.54KΩ, and the second filter resistor R2 can be 12.3KΩ, so that the cut-off frequency f is approximately equal to 50MHz. The first feedback resistor Rf1 can be 2.7KΩ, and the first voltage divider resistor R3 can be 22.1KΩ, so that A' is approximately 1.2. In this way, the LT1363 chip can be operated in a steady state, avoiding the LT1363 chip from being in a saturated state, thereby ensuring the filtering effect of the high-pass filter circuit 21.

[0084] In addition, if Figure 2 As shown, the first feedback resistor Rf1 can be connected in series with the first voltage divider resistor R3 and then grounded. This can stabilize the electromagnetic compatibility (EMC) instability caused by the combination of the operational amplifier A1 and the subsequent half-wave rectifier circuit 22, which is beneficial to improving the EMC problem of the cable power supply detection device 100.

[0085] Please continue reading Figure 2 The half-wave rectifier circuit 22 includes a voltage limiting amplifier A2, a feedback resistor, a voltage dividing resistor and a second bypass capacitor.

[0086] The voltage limiting amplifier A2 is an operational amplifier with an output voltage limiting function. Therefore, in addition to a positive power supply terminal, a negative power supply terminal, a non-inverting input terminal, an inverting input terminal and an output terminal, the voltage limiting amplifier A2 also has a first voltage limiting terminal and a second voltage limiting terminal.

[0087] The feedback resistor and the voltage-dividing resistor can be a resistor element, or they can be composed of multiple resistor elements connected in series, in parallel, or in series and in parallel. The second bypass capacitor can be a capacitor element, or it can be composed of multiple resistor elements connected in series, in parallel, or in series and in parallel. It is not limited here. For ease of description, the embodiment of the present application takes the feedback resistor of the half-wave rectifier circuit 22 as resistor Rf2 (hereinafter referred to as the second feedback resistor), the voltage-dividing resistor of the half-wave rectifier circuit 22 as resistor R5 (hereinafter referred to as the second voltage-dividing resistor), and the second bypass circuit is formed by capacitor C6 and capacitor C7 in parallel as an example for display.

[0088] Specifically, the positive power supply terminal of the voltage limiting amplifier A2 is used to access the positive power supply voltage +Vs2, and the negative power supply terminal of the voltage limiting amplifier A2 is used to access the negative power supply voltage -Vs2. The positive power supply terminal and the negative power supply terminal of the voltage limiting amplifier A2 are also grounded through the second bypass capacitor respectively to stabilize the connected power supply voltage. The in-phase input terminal of the voltage limiting amplifier A2 is used to connect to the output terminal of the operational amplifier A1, and the inverting input terminal of the voltage limiting amplifier A2 is connected to the output terminal of the voltage limiting amplifier A2 through the second feedback resistor Rf2, and the inverting input terminal of the voltage limiting amplifier A2 is also grounded through the second voltage-dividing resistor R5. The first voltage limiting terminal of the voltage limiting amplifier A2 is used to access the clamping voltage VH, and the clamping voltage VH is greater than 0. The second voltage limiting terminal of the voltage limiting amplifier A2 is used for grounding, in other words, the second voltage limiting terminal is used to access the 0 voltage.

[0089] Based on such a design, the voltage limiting amplifier A2 can be used to perform in-phase amplification on the second high-frequency voltage Vhf2 according to the second feedback resistor Rf2 and the second voltage-dividing resistor R5, with an amplification factor A"=1+Rf2 / R5, and to limit the voltage according to the clamping voltage VH connected to the first voltage limiting end and the 0 voltage connected to the second voltage limiting end, thereby outputting a pulsating voltage Vp.

[0090] It is further understood that since the second high-frequency voltage Vhf2 is converted from a high-frequency pulse current, the second high-frequency voltage Vhf2 is essentially a pulse voltage with periodicity. Therefore, a portion of the second high-frequency voltage Vhf2 is in the positive half cycle, that is, greater than 0, and a portion is in the negative half cycle, that is, less than 0. Correspondingly, when the voltage limiting amplifier A2 processes the second high-frequency voltage Vhf2, it can set a corresponding upper limit based on the clamping voltage VH connected to the first voltage limiting terminal, and can set a corresponding lower limit 0 based on the 0 voltage connected to the second voltage limiting terminal, thereby limiting the pulsating voltage Vp between the upper and lower limits, that is, the pulsating voltage Vp is not less than 0 and not greater than the upper limit voltage.

[0091] It can be seen that based on the characteristics of the above-mentioned voltage limiting amplifier A2, the half-wave rectification circuit 22 can achieve half-wave rectification and amplification of the second high-frequency voltage.

[0092] Among them, based on the half-wave rectification function, the pulsating voltage Vp can be placed in the positive half cycle, thereby reducing the switching time of the PNP semiconductor transistor in the voltage limiting amplifier A2, thereby effectively improving the processing speed of the voltage limiting amplifier A2, and there is no need to set up a diode for voltage limiting. Based on the amplification function, there is no need to set up an amplification circuit to amplify the second high-frequency voltage Vhf2 or the pulsating voltage Vp. Therefore, the processing efficiency of the half-wave rectification circuit 22 of the embodiment of the present application can be improved, the component cost can be reduced, and the occupied space of the half-wave rectification circuit 22 can be reduced.

[0093] In the embodiment of the present application, the model parameters of each component in the half-wave rectifier circuit 22 can be determined according to actual needs. For example, the voltage limiting amplifier A2 can use a high-gain wide-band operational amplifier chip with a built-in voltage limiting function, such as an operational amplifier chip with model OPA699. It can be understood that the OPA699 chip can provide bipolar output voltage limiting, a conversion rate of up to 1400V / μs, a gain-bandwidth product of up to 1000MHz, a bandwidth of up to 260MHz, and a recovery time of up to 1ns. It can be seen that the capacity of the OPA699 chip is sufficient to handle the second high-frequency voltage Vhf2, and it will not cause too much voltage loss of the second high-frequency voltage Vhf2.

[0094] To match the OPA699 chip, in the second bypass capacitor, capacitor C6 can be 10uF, and capacitor C7 can be 0.1uF. For another example, the second feedback resistor Rf2 can be 750Ω, and the second voltage divider resistor R5 can be 150Ω, so that A" is equal to 6. In this way, the half-wave rectifier circuit 22 can constitute a precise half-wave rectifier circuit 22, and can work in a stable state, thereby ensuring the half-wave rectification effect, and avoiding the power supply stability detection error caused by the unstable output of the half-wave rectifier circuit 22.

[0095] In addition, since the voltage limiting amplifier A2 is combined with the operational amplifier A1 in the half-wave rectifier circuit 22, in order to avoid mutual interference between the two chips, the half-wave rectifier circuit 22 also includes a first coupling capacitor C5 and a matching resistor R4.

[0096] Specifically, the first coupling capacitor C5 can be connected between the non-inverting input terminal of the voltage limiting amplifier A2 and the output terminal of the operational amplifier A1. In this way, the first coupling capacitor C5 can couple and isolate the voltage limiting amplifier A2 of the subsequent stage and the operational amplifier A1 of the previous stage. The size of the first coupling capacitor C5 can be set accordingly according to actual conditions, for example, it can be 100nF.

[0097] The in-phase input terminal of the voltage limiting amplifier A2 can be grounded through the matching resistor R4. The matching resistor R4 can adjust the impedance difference between the half-wave rectifier circuit 22 and the high-pass filter circuit 21, improve the crosstalk caused by impedance imbalance, signal delay, etc., and thus the amplitude and waveform change of the second high-frequency voltage Vhf2, thereby improving the signal transmission quality and helping to improve the accuracy of cable power supply stability detection. Among them, the matching resistor R4 can be set with reference to international standards, for example, a 50Ω resistor can be used as the matching resistor R4.

[0098] Please refer again Figure 2 , the detection circuit 23 includes a second coupling capacitor C8, a first detection diode D1, a second detection diode D2 and an RC parallel circuit. The RC parallel circuit includes a detection capacitor and a load resistor. Among them, the structural design of the detection capacitor is the same or similar to that of the first filter capacitor, and the structural design of the load resistor is the same or similar to that of the first filter resistor, so it is not repeated here. For the convenience of description, the embodiment of the present application is shown by taking the detection capacitor as capacitor C9 and the load resistor as resistor R6 as an example.

[0099] One end of the second coupling capacitor C8 is connected to the output end of the voltage limiting amplifier A2 to access the pulsating voltage Vp. The other end of the second coupling capacitor C8 is connected to the anode of the first detection diode D1. Based on this, the second coupling capacitor C8 can couple and isolate the subsequent detection diode circuit (i.e., the first detection diode D1, the second detection diode D2 and the RC parallel circuit) and the previous voltage limiting amplifier A2 to avoid mutual interference between the two circuits.

[0100] The first detector diode D1 and the second detector diode D2 are connected in reverse parallel, that is, the anode of the first detector diode D1 is connected to the cathode of the second detector diode D2, and the cathode of the first detector diode D1 is connected to the anode of the second detector diode D2. The load resistor R6 is connected in parallel with the detection capacitor C9, and the parallel load resistor R6 and the detection capacitor C9 are connected between the cathode of the first detection diode and the anode of the second detection diode D2. In addition, the load resistor R6 and a connection midpoint in the detection capacitor C9 used to be connected to the cathode of the first detection diode D1, that is, the cathode of the first detection diode D1 can lead to an output terminal a. The load resistor R6 and a connection midpoint in the detection capacitor C9 used to be connected to the anode of the second detection diode D2, and the anode of the second detection diode D2 are both grounded. The load resistor R6 can serve as a discharge channel for the detection capacitor C9.

[0101] Based on such a design, when the voltage limiting amplifier A2 outputs the pulsating voltage Vp, the second coupling capacitor C8 is charged first to generate a voltage drop Vc8. When the pulsating voltage Vp is greater than the forward conduction voltage drop of the first detection diode D1, the first detection diode D1 is turned on. At this time, the first detection diode D1 and the detection capacitor C9 can form a charging circuit, so the pulsating voltage Vp and the voltage drop Vc8 can be transmitted to the detection capacitor C9 through the turned-on first detection diode D1, and the detection capacitor C9 is charged, so that the output end of the detection circuit 23 can output a DC voltage Vdc.

[0102] Among them, since the cathode of the second detection diode D2 is connected to the pulsating voltage Vp, the second detection diode D2 is cut off, which can ensure that the pulsating voltage Vp is always transmitted to the first detection diode D1. In addition, the first detection diode D1 and the second detection diode D2 can both use surface mount components (SMD). Since SMD has no pins, it can avoid causing noise interference.

[0103] In the embodiment of the present application, the DC voltage Vdc is greater than the pulsating voltage Vp, and the frequency of the DC voltage Vdc is lower than the frequency of the pulsating voltage Vp. It can be seen that the detection circuit 23 can detect the pulsating voltage Vp into a smoother and larger-amplitude DC voltage Vdc. This detection process can also be understood as a rectification and amplitude modulation process of the pulsating voltage Vp. Among them, the magnitude of the DC voltage Vdc can be adjusted accordingly according to actual needs. For example, in some embodiments, Vdc=2Vp.

[0104] In the embodiment of the present application, the frequency of the DC voltage Vdc reaches a preset steady-state frequency. For example, when the first high-frequency voltage Vhf1 is greater than the upper limit of the preset steady-state frequency of 50MHz, the frequency of the DC voltage Vdc obtained after the first high-frequency voltage Vhf1 is processed by the frequency reduction module 2 can be reduced to below 50MHz, for example, within the range of 1MHz to 50MHz. Based on such a design, the recovery time of the detection circuit 23 can be reduced, so that the detection circuit 23 can better perform the detection function, thereby improving the output quality.

[0105] Please refer again Figure 1 The cable power supply detection device 100 also includes a sampling module 3 and a control module 4.

[0106] The sampling module 3 is connected to the output terminal a of the detection circuit 23 and the control module 4. The sampling module 3 can be used to sample the DC voltage Vdc, and output the sampled voltage to the control module 4. Then, the control module 4 can compare the sampled voltage with the preset safety threshold, and output an alarm signal when the sampled voltage is greater than the preset safety threshold.

[0107] It can be understood that when a partial discharge occurs in the cable 200, there will be a high-frequency pulse current in the current transmitted by the cable 200. When the current sensor 1 senses a high-frequency pulse current and is processed by the frequency reduction module 2 and the sampling module 3, a larger sampling voltage can be obtained. Therefore, when the sampling voltage is greater than the preset safety threshold, it means that the power supply of the cable 200 is unstable at this time, and a partial discharge phenomenon may occur. Therefore, the alarm signal can be used to indicate that the power supply of the cable 200 is unstable. On the contrary, when the sampling voltage is less than the preset safety threshold, it means that the power supply of the cable 200 is stable at this time, so the control module 4 does not output an alarm signal.

[0108] Among them, since the stability of the power transmitted by the cable 200 is affected by the power system environment and the load environment, the preset safety threshold can be set accordingly according to the actual power system environment, the load environment, etc., and is not specifically limited here. For example, in some embodiments, the preset safety threshold can be set to 50mv±10mv. In addition, to ensure that the sampling module 3 can sample the DC voltage Vdc, the frequency of the DC voltage Vdc is within the sampling frequency range of the sampling module 3.

[0109] The sampling module 3 may adopt any circuit or element that can realize the above voltage sampling function, which is not limited here. For example, when the frequency of the DC voltage Vdc is in the range of 1MHz to 50MHz, Figure 4As shown, the sampling module 3 can use an analog to digital converter (ADC) chip, such as a high-precision AD7606 chip. The AD7606 chip can convert the DC voltage Vdc into a corresponding digital signal and give it to the control module 4.

[0110] Among them, since the sampling rate of the AD7606 chip can reach 200kSPS, that is, 200MHz, it can cover the frequency of the DC voltage Vdc.

[0111] It can be understood here that since the price of the ADC chip will increase as the sampling frequency of the ADC chip increases, in the embodiment of the present application, since the voltage is first downconverted to a lossless frequency through the downconversion module 2, and amplified by the downconversion module 2 to reduce the voltage transmission loss so that the output is not distorted, a smaller ADC chip with a suitable sampling frequency can be used for the subsequent sampling module 3, which is beneficial to reduce the cost of the cable power supply detection device 100.

[0112] In addition, the AD7606 chip has a simple configuration, and the sampling rate can be controlled by the pulse frequency provided by the control module 4. Therefore, the use of the AD7606 chip can be very simple and convenient.

[0113] Moreover, the AD7606 chip can realize 8-channel synchronous sampling. Therefore, the AD7606 chip can meet the requirements of the cable power supply detection device 100 for simultaneous and synchronous detection of multi-phase cable power supply conditions. For example, Figure 1 As shown, when it is necessary to detect the power supply stability of a three-phase cable, the cable power supply detection device 100 can be provided with three current sensors 1, three frequency reduction modules 2, a sampling module 3, and a control module 4. Each current sensor 1 corresponds to a frequency reduction module 2 and a one-phase cable. The three frequency reduction modules 2 are all connected to the AD7606 chip. In this way, the AD7606 chip can synchronously sample three DC voltages and output the three sampling voltages to the control module 4. The control module 4 can then determine whether there is any cable in the three-phase cable with unstable power supply according to the three sampling voltages.

[0114] In the embodiment of the present application, the control module 4 may be a microcontroller (MCU) or other control circuits, which are not limited here. Figure 4As shown, the control module 4 can adopt STM32 chips, such as STM32F series chips. It can be understood that the STM32F series chips are low-density performance series chips with low prices, which can help reduce the cost of the cable power supply detection device 100. Moreover, since the STM32F series chips run at a frequency of 72MHz, and are equipped with ARM and high-speed embedded memory (up to 32KB of flash memory FLASH and up to 6KB of static random access memory SRAM, SRAM can be used as a buffer register BUFFER), three general 16-bit timers and a pulse width modulation (Pulse Width Modulation, PWM) timer, two peripheral buses, multiple standard and advanced communication interfaces (such as I2C interface, SPI interface, FSMC interface, USART interface, USB interface and CAN interface, etc.) can be provided, therefore, the STM32F series chips are sufficient to cope with the control of the sampling module 3 and peripheral devices in the embodiment of the present application.

[0115] Further examples such as Figure 4 As shown in the figure, the STM32F series chip can be connected to the AD7606 chip through the SPI interface and the FSMC interface. SPI is a synchronous serial peripheral interface that can communicate with the AD7606 chip in a serial manner, such as providing a pulse frequency to the AD7606 chip to control the sampling rate of the AD7606 chip. The FSMC interface is a parallel interface. After the STM32F series chip is initialized, the AD7606 chip can transmit the sampled sampling signal to the FSMC interface at high speed, and the FSMC interface then moves the sampling signal to the SRAM of the high-speed embedded memory. The STM32F series chip then reads the stored sampling signal. After the sampling signal in the SRAM is read, it will be refreshed to re-store the new sampling signal.

[0116] It can be understood that the AD7606 chip can perform sampling and iterative refreshing with an action time of 5μs (that is, 1 / 200kSPS), and send the sampled voltage to the bus in the STM32F series chip, and the bus rate reaches 5ns (that is, 1 / 200MSPS). Therefore, the STM32F series chip is sufficient to move the sampled voltage collected by the AD7606 chip into the SRAM when the AD7606 chip samples next time.

[0117] Please also refer to Figure 3 and Figure 4 The cable power supply detection device 100 may further include an alarm module 5. The alarm module 5 is connected to the control module 4. Therefore, the control module 4 may output an alarm signal to the alarm module 5.

[0118] The alarm module 5 may be, for example, a buzzer, an audible alarm, a display screen, or other device that can visualize and / or audibly display the alarm signal. The STM32F series chip may be connected to the alarm module 5 via a GPIO interface, and output a high level to the alarm module 5 via the GPIO interface to trigger the alarm module 5 to sound an alarm. The high level is the alarm signal.

[0119] Based on the alarm signal, relevant personnel can learn that the current power supply of the cable 200 is unstable, and can then promptly check the factors causing the unstable power supply and take corresponding measures, thereby preventing short circuits and power outages from occurring.

[0120] Please refer again Figure 3 and Figure 4 , the cable power supply detection device 100 may further include a communication module 6. The communication module 6 is connected to the control module 4. Therefore, the control module 4 can be connected to the terminal device 300 of the relevant personnel through the communication module 6, and transmit the alarm signal to the terminal device 300 through the communication module 6 to remind the relevant personnel that the current power supply of the cable 200 is unstable. In addition, the control module 4 can also send information such as the sampled voltage to the terminal device 300 through the communication module 6 so that the relevant personnel can check and analyze.

[0121] Among them, the communication module 6 can be a wireless communication module 6, such as a WIFI module, a Bluetooth module or a 2G / 3G / 4G / 5G / 6G / 7G module, etc., which is not limited here. For example, the communication module 6 can use a WIFI module of model ESP8266. The ESP8266 module can be used independently or can be mounted on the control module 4 for operation. When ESP8266 is used independently, it can be directly controlled and started by an external FLASH (for example, the FLASH of the STM32F series chip). Figure 4 As shown, when the ESP8266 module is mounted on the control module 4, the control module 4 can be connected to communicate through the UART interface. Of course, in other embodiments, the ESP8266 module can also be connected to the control module 4 through the SPI interface or the SDIO interface. The terminal device 300 can be an electronic device such as a mobile phone, a tablet, a computer, a smart wearable device, a host computer, etc., which is not limited here.

[0122] In addition, to ensure that the circuit is usable, the embodiment of the present application also conducts experimental tests on the half-wave rectifier circuit 22 and the sampling module 3.

[0123] See also Figure 5 , shows the input and output waveforms of the half-wave rectifier circuit 22. Figure 5As shown, when the half-wave rectifier circuit 22 adjusts A"=3, when the half-wave rectifier circuit 22 inputs the second high-frequency voltage 500mVp-p, 500kHz (corresponding to channel 1), the half-wave rectifier circuit 22 can output a pulsating voltage of about 1.5Vp-p (corresponding to channel 2). Obviously, the output is about three times the input. Moreover, the voltage of the negative half cycle is limited to 0, so that the waveform of the entire pulsating voltage is in the positive half cycle.

[0124] It can be seen that the half-wave rectifier circuit 22 can achieve gain amplification and half-wave rectification functions. Moreover, due to the gain amplification of the half-wave rectifier circuit 22, during the pulsating voltage transmission process, the output will not be distorted due to line loss, resulting in an inability to accurately judge. Therefore, the half-wave rectifier circuit 22 of the embodiment of the present application is applicable.

[0125] See also Figure 6 , shows the output waveform of the sampling module 3. Figure 6 As shown, when the sampling module 3 inputs a sine wave voltage of 1V (corresponding to an ADC value of 3267.7) and 3kHz, the sampling module 3 can output a sine wave, and the ADC value is about 3200, and the error between this value and the actual input 3267.7 does not exceed 5%. Therefore, the sampling module 3 can achieve effective sampling of the input. The sampling module 3 of the embodiment of the present application is available.

[0126] Next, the working principle of the cable power supply detection device 100 according to the embodiment of the present application is described.

[0127] First, the current sensor 1 detects the high-frequency pulse current transmitted by the cable 200 , and when the high-frequency pulse current is sensed, the high-frequency pulse current is converted into a first high-frequency voltage Vhf1 and output to the high-pass filter circuit 21 .

[0128] The first high-frequency voltage Vhf1 is high-pass filtered by the high-pass filter circuit 21, and then half-wave rectified and amplified by the half-wave rectifier circuit 22 to be converted into a pulsating voltage Vp not less than 0. The pulsating voltage Vp is then detected by the detection circuit 23 to be converted into a DC voltage Vdc, wherein the DC voltage Vdc is greater than the pulsating voltage Vp, and the frequency of the DC voltage Vdc is lower than the frequency of the pulsating voltage Vp.

[0129] Next, the control module 4 drives the sampling module 3 to sample the DC voltage Vdc, thereby obtaining a sampled voltage and comparing the sampled voltage with a preset safety threshold.

[0130] When the sampling voltage is greater than the preset safety threshold, the control module 4 outputs an alarm signal to the alarm module 5, and / or the control module 4 outputs the alarm signal to the terminal device 300 through the communication module 6. The alarm module 5 can sound an alarm when receiving the alarm signal, and the terminal device 300 can visualize the information corresponding to the alarm signal when receiving the alarm signal, so that relevant personnel can know that there is a high-energy pulse signal on the cable 200 where the current sensor 1 is located, and the power supply of the cable 200 is unstable, and special attention should be paid to this location and corresponding emergency measures should be taken.

[0131] When the sampled voltage is less than the preset safety threshold, the control module 4 does not output an alarm signal, and the control module 4 continues to drive the sampling module 3 to sample a new DC voltage and continue to interpret it.

[0132] In summary, the cable power supply detection device 100 of the embodiment of the present application is provided with a current sensor 1, a frequency reduction module 2, a sampling module 3 and a control module 4. The current sensor 1 detects the high-frequency pulse current in the cable 200 and converts it into a first high-frequency voltage. The first high-frequency voltage is filtered by a high-pass filter circuit 21, and then half-wave rectified and amplified by a half-wave rectifier circuit 22, and then detected by a detection circuit 23. A DC voltage can be obtained. The DC voltage is not less than 0 and the frequency is lower than the frequency of the first high-frequency voltage. The DC voltage can be converted into a sampling voltage after sampling and processing by the sampling module 3. Then, the control module 4 can judge the power supply stability of the cable 200 based on the size of the sampling voltage, thereby outputting an alarm signal in the case of unstable power supply. In this way, automatic detection and automatic alarm of the stability of the cable power supply can be realized. Based on the alarm signal, relevant personnel can be informed that the cable power supply is unstable, so that relevant measures can be taken in time to prevent accidents in advance and reduce the cost losses caused by accidents.

[0133] Compared with the current manual inspection method by professionals, the cable power supply detection device 100 of the embodiment of the present application can improve the detection efficiency, reduce the detection cost, and can also be applied to various power usage scenarios, with a wide range of applications.

[0134] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A cable power supply detection device, It is characterized in that It includes a current sensor, a frequency reduction module, a sampling module and a control module; The current sensor is used to detect the high-frequency pulse current transmitted by the cable, thereby generating a first high-frequency voltage, the frequency of which is greater than a preset steady-state frequency; The frequency reduction module includes a high-pass filter circuit, a half-wave rectifier circuit and a detection circuit, wherein: The high-pass filter circuit is connected to the current sensor, and is used to perform high-pass filtering on the first high-frequency voltage, thereby outputting a second high-frequency voltage; The half-wave rectifier circuit is connected to the high-pass filter circuit and the detection circuit, and is used for performing half-wave rectification and amplification on the second high-frequency voltage, thereby outputting a pulsating voltage, and the pulsating voltage is not less than 0; The detection circuit is used to detect the pulsating voltage into a direct current voltage, wherein the direct current voltage is greater than the pulsating voltage and reaches the preset steady-state frequency; The sampling module is connected to the detection circuit, and the sampling module is used to sample the DC voltage, thereby outputting a sampled voltage; The control module is connected to the sampling module, and the control module is used to output an alarm signal when the sampling voltage is greater than a preset safety threshold, and the alarm signal is used to indicate that the power supply of the cable is unstable.

2. The cable power supply detection device according to claim 1, It is characterized in that The half-wave rectifier circuit includes a voltage limiting amplifier, a feedback resistor and a voltage dividing resistor, wherein: The non-inverting input terminal of the voltage limiting amplifier is used to connect to the high-pass filter circuit to access the second high-frequency voltage, the inverting input terminal of the voltage limiting amplifier is connected to the output terminal of the voltage limiting amplifier through the feedback resistor, the inverting input terminal of the voltage limiting amplifier is also grounded through the voltage dividing resistor, and the output terminal of the voltage limiting amplifier is connected to the detection circuit; The first voltage limiting terminal of the voltage limiting amplifier is used to access a clamping voltage, and the clamping voltage is greater than 0; the second voltage limiting terminal of the voltage limiting amplifier is used to be grounded; The voltage limiting amplifier is used to perform voltage limiting amplification on the second high-frequency voltage according to the feedback resistor, the voltage dividing resistor, the clamping voltage connected to the first voltage limiting terminal and the zero voltage connected to the second voltage limiting terminal, thereby outputting the pulsating voltage.

3. The cable power supply detection device as claimed in claim 2, It is characterized in that The half-wave rectifier circuit also includes a first coupling capacitor and a matching resistor. The in-phase input terminal of the voltage limiting amplifier is connected to the high-pass filter circuit via the first coupling capacitor, and the in-phase input terminal of the voltage limiting amplifier is grounded via the matching resistor.

4. The cable power supply detection device according to claim 2, It is characterized in that The voltage limiting amplifier is an OPA699 chip.

5. The cable power supply detection device according to claim 1, It is characterized in that The high-pass filter circuit includes a passive high-pass filter and a common-phase amplifier circuit, wherein: The passive high-pass filter is connected to the current sensor and is used to perform high-pass filtering on the first high-frequency voltage; The passive high-pass filter is also connected to the in-phase input end of the in-phase amplifier circuit, and the output end of the in-phase amplifier circuit is connected to the half-wave rectifier circuit. The in-phase amplifier circuit is used to perform in-phase amplification on the first high-frequency voltage after high-pass filtering, thereby outputting the second high-frequency voltage.

6. The cable power supply detection device according to claim 5, It is characterized in that The passive high-pass filter includes a first filter capacitor, a second filter capacitor, a first filter resistor and a second filter resistor, one end of the first filter capacitor is connected to the current sensor, the other end of the first filter capacitor is connected to one end of the second filter capacitor and the output end of the common-phase amplifier circuit through the first filter resistor, and the other end of the second filter capacitor is connected to the common-phase input end of the common-phase amplifier circuit and is grounded through the second filter resistor.

7. The cable power supply detection device according to claim 1, It is characterized in that The detection circuit includes a second coupling capacitor, a first detection diode, a second detection diode and an RC parallel circuit; One end of the second coupling capacitor is connected to the output end of the half-wave rectifier circuit, and the other end of the second coupling capacitor is connected to the anode of the first detection diode, and the first detection diode and the second detection diode are connected in reverse parallel; The RC parallel circuit is connected between the cathode of the first detection diode and the anode of the second detection diode. The RC parallel circuit is also connected to the sampling module and ground. The RC parallel circuit is used to receive the pulsating voltage when the first detection diode is turned on, thereby outputting the DC voltage.

8. The cable power supply detection device according to claim 1, It is characterized in that The frequency of the DC voltage is within the sampling frequency range of the sampling module.

9. The cable power supply detection device according to claim 1, It is characterized in that The frequency of the DC voltage is in the range of 1 MHz to 50 MHz.

10. The cable power supply detection device according to claim 1, It is characterized in that The cable power supply detection device also includes: An alarm module, connected to the control module, the control module is used to output the alarm signal to the alarm module; And / or, a communication module, connecting the control module and the terminal device, the communication module is used to transmit the alarm signal to the terminal device.

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