Power taking method based on cable metal sheath, electronic device and storage medium

Abstract

Embodiments of the present application provide a method for taking power based on cable metal sheath, electronic equipment and storage medium. The method comprises: electrically connecting a first input end of a power taking device with a first phase cable metal sheath and electrically connecting a second input end of the power taking device with a second phase cable metal sheath, wherein the first phase and the second phase are two phase metal sheaths forming a power taking loop after opposite installation; acquiring an induced electromotive force between the two phase metal sheaths through the power taking device; converting the induced electromotive force into pulsating direct current through rectification processing; converting the pulsating direct current into stable direct current through isolation conversion processing and outputting to a load, so as to form electrical isolation between a preset potential of the metal sheath and a load side while providing stable power for the load. The effect of realizing stable and efficient power taking without affecting the safety of single-core cable metal sheath grounding and reducing the risk of high potential conduction is achieved.

Description

Technical Field

[0001] This application relates to the field of power cable energy harvesting technology, and in particular to an energy harvesting method, electronic device and storage medium based on the metal sheath of a cable. Background Technology

[0002] In single-core high-voltage cable systems, the metal sheath is typically grounded at one end or cross-connected, and is protected by sheath protection devices to limit induced voltage and ensure safe power transmission operation.

[0003] However, existing energy harvesting schemes for sheaths are mostly achieved by connecting a series grounding circuit or adding an external induction component. The former is prone to affecting the potential relationship of the original grounding system and increasing operational risks, while the latter is cumbersome to construct and does not match the energy characteristics of the sheath well, making it difficult to balance energy harvesting efficiency, system compatibility and electrical safety.

[0004] Therefore, how to achieve stable and efficient energy extraction without affecting the grounding safety of the metal sheath of single-core cables, and reduce the risk of high-potential conduction, has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides an energy harvesting method, electronic device, and storage medium based on the metal sheath of a cable, which can achieve stable and efficient energy harvesting without affecting the grounding safety of the metal sheath of a single-core cable, and reduce the risk of high-potential conduction.

[0006] In a first aspect, embodiments of this application provide an energy harvesting method based on the metallic sheath of a cable, comprising:

[0007] The first input terminal of the energy harvesting device is electrically connected to the metal sheath of the first phase cable, and the second input terminal of the energy harvesting device is electrically connected to the metal sheath of the second phase cable, wherein the first phase and the second phase are two metal sheaths that form an energy harvesting circuit after being swapped.

[0008] The induced electromotive force between the two-phase metal sheaths is obtained through an energy harvesting device.

[0009] The induced electromotive force is rectified and converted into pulsating direct current.

[0010] The pulsating DC power is converted into stable DC power through isolation transformation and output to the load. This provides stable power to the load while forming electrical isolation between the preset potential of the metal sheath and the load side. The preset potential is the ground potential of the metal sheath, with a maximum value of 300V. The isolation withstand voltage level of the isolation transformation process is configured to be greater than the maximum value of the preset potential.

[0011] In one possible embodiment, the first phase and the second phase are configured as a two-phase metal sheath that forms an energy harvesting circuit after being interchanged, including:

[0012] Keep the original grounding method of two of the metal sheaths unchanged;

[0013] After swapping the positions of the grounding terminal and the floating terminal of the remaining phase metal sheath, grounding is performed to eliminate the floating state and to form an energy extraction circuit between the two phase metal sheaths.

[0014] In one possible embodiment, the induced electromotive force between the two-phase metal sheaths is obtained through an energy harvesting device, including:

[0015] The induced electromotive force generated by the cable's operating current on the two-phase metallic sheath is used as an energy source, and the magnitude of the induced electromotive force is positively correlated with the cable's operating current and mutual impedance.

[0016] In one possible embodiment, the induced electromotive force is rectified and converted into pulsating direct current, including:

[0017] A rectifier bridge is used to rectify the induced electromotive force to obtain pulsating direct current;

[0018] A capacitor is used to filter the pulsating DC current.

[0019] In one possible embodiment, the pulsating DC power is converted into stable DC power through isolation conversion and then output to the load, including:

[0020] Pulsating DC power is input to the flyback converter, which is used to achieve electrical isolation through high-frequency transformation.

[0021] Ground the output of the flyback converter to isolate the high voltage potential of the metal sheath;

[0022] The output voltage of the flyback converter is set according to the load requirements, and a stable DC power is output to the load.

[0023] In one possible embodiment, it also includes:

[0024] An overvoltage protection circuit is provided on the primary side of the flyback converter. The overvoltage protection circuit includes a circuit breaker and a sheath protector.

[0025] The input voltage on the primary side of the flyback converter is collected. When the input voltage exceeds a preset threshold, the circuit breaker is triggered to trip.

[0026] In one possible embodiment, it also includes:

[0027] Collect the output voltage at the output terminal of the flyback converter;

[0028] The output voltage is compared with the reference voltage to obtain the deviation value;

[0029] The duty cycle is calculated based on the deviation value using proportional-integral control, and the output of the flyback converter is adjusted according to the duty cycle to stabilize the output voltage.

[0030] Secondly, embodiments of this application provide an energy harvesting device based on the metal sheath of a cable, comprising:

[0031] The connection module is used to electrically connect the first input terminal of the energy harvesting device to the metal sheath of the first phase cable, and to electrically connect the second input terminal of the energy harvesting device to the metal sheath of the second phase cable, wherein the first phase and the second phase are two metal sheaths that form an energy harvesting circuit after being swapped.

[0032] The acquisition module is used to acquire the induced electromotive force between the two-phase metal sheaths through an energy harvesting device.

[0033] The conversion module is used to convert the induced electromotive force into pulsating direct current through rectification.

[0034] The output module converts pulsating DC power into stable DC power through isolation transformation and outputs it to the load. This provides stable power to the load while establishing electrical isolation between the preset potential of the metal sheath and the load side. The preset potential is the ground potential of the metal sheath, with a maximum value of 300V. The isolation withstand voltage rating of the isolation transformation process is configured to be greater than the maximum value of the preset potential.

[0035] Thirdly, embodiments of this application provide an energy harvesting device based on the metal sheath of a cable, including: a memory and a processor;

[0036] The memory stores computer-executed instructions;

[0037] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0038] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0039] Fifthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0040] The energy harvesting method, electronic device, and storage medium based on the metal sheath of a cable provided in this application connect the first and second input terminals of the energy harvesting device to the metal sheaths of two-phase cables that form an energy harvesting circuit after being swapped, and obtain the induced electromotive force between the two-phase metal sheaths. This allows for direct energy harvesting based on the induced energy of the metal sheath itself, avoiding additional series connection effects on the original grounding circuit, thereby improving the compatibility of the energy harvesting scheme with the grounding system of a single-core high-voltage cable. By rectifying the induced electromotive force into pulsating DC power and further isolating and converting it into stable DC power for output to the load, effective rectification, voltage stabilization, and isolated power supply of the induced energy of the sheath can be achieved. This reduces the risk of high-voltage potential from the metal sheath being conducted to the load side while providing stable power to the load, thus improving overall electrical safety. Attached Figure Description

[0041] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0042] Figure 1 A flowchart illustrating the energy harvesting method based on the cable's metallic sheath provided in this application. Figure 1 ;

[0043] Figure 2 A schematic diagram of the existing cable sheath grounding system energy harvesting device provided in this application when used for single-end grounding;

[0044] Figure 3 This is a schematic diagram of a single-ended grounding system in the prior art.

[0045] Figure 4 This is a schematic diagram of a single-ended phase-inverted grounding provided in this application;

[0046] Figure 5 This is a schematic diagram of the single-ended phase-inverting grounding impedance connection provided in this application;

[0047] Figure 6 The single-ended phase-inverting grounding energy extraction circuit diagram provided in this application;

[0048] Figure 7 This application provides a schematic diagram showing the location of the power cables.

[0049] Figure 8 The control loop diagram provided in this application;

[0050] Figure 9 A schematic diagram of the energy harvesting device based on the metal sheath of a cable provided in this application;

[0051] Figure 10 A schematic diagram of the energy harvesting device based on the metal sheath of a cable provided in this application.

[0052] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0053] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application.

[0054] The single-core high-voltage cable metallic sheath grounding and energy extraction technology is mainly applied to 35kV and above power cable transmission systems, with typical scenarios including cable tunnels, integrated utility tunnels, substation outgoing line sections, and urban underground power transmission channels. In these systems, when the cable core transmits a large current, an electromotive force is induced in the metallic sheath. Therefore, a metallic sheath grounding circuit and corresponding protection devices are usually required to ensure that the sheath potential is controlled and meets the requirements for long-term safe operation.

[0055] Existing single-core cable sheath systems typically employ single-end grounding or cross-interconnected grounding methods, along with sheath protection devices to limit induced voltage. Regarding sheath energy utilization, existing solutions mostly involve connecting an energy harvesting unit in series in the grounding circuit, or adding an inductive energy harvesting component outside the cable. This allows the cable to obtain electrical energy through induced current or magnetic field coupling, which is then rectified and regulated before supplying power to the monitoring equipment.

[0056] While the above solutions can achieve energy harvesting to some extent, connecting them in series with the grounding loop can easily alter the original grounding potential relationship, making the sheath's operating state more complex. In severe cases, it may even introduce the risk of abnormal potential transmission, affecting grounding safety and system reliability. External induction component solutions often rely on additional installation space and specialized construction, resulting in complex structures and high costs. Moreover, the energy harvesting object and the energy characteristics of the metal sheath itself are not well matched, leading to unstable usable energy and limited efficiency.

[0057] Furthermore, if the existing solution lacks effective isolation measures after extracting energy from the sheath side, the high voltage potential that may exist in the metal sheath may be conducted to the load side, thereby threatening the operational safety of low-voltage equipment such as monitoring terminals and communication modules, and also increasing the electrical protection pressure during on-site operation and maintenance.

[0058] In view of this, how to achieve stable energy harvesting and reduce the risk of high potential conduction to the load side without affecting the grounding safety of the single-core cable's metal sheath has become an urgent technical problem to be solved. To solve the above problem, an energy harvesting method based on the cable's metal sheath is proposed. By electrically connecting the two input terminals of the energy harvesting device to the two phase metal sheaths that form an energy harvesting circuit after being swapped, the induced electromotive force between the two phase metal sheaths is obtained. This electromotive force is then rectified and isolated sequentially to convert it into a stable DC output to the load, thereby realizing the utilization of sheath energy while forming electrical isolation between the high-voltage potential of the metal sheath and the load side. For the end that has not been swapped (i.e., the other phase or the other side of the metal sheath that is not connected to the energy harvesting circuit), existing power supply schemes can be used to supply power to the load on the corresponding side. The specific implementation method is not within the scope of protection of this application and will not be described here.

[0059] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0060] Figure 1 A flowchart illustrating the energy harvesting method based on the cable's metallic sheath provided in this application. Figure 1 ,like Figure 1 As shown, the method includes:

[0061] S101: Connect the first input terminal of the energy harvesting device to the metal sheath of the first phase cable, and connect the second input terminal of the energy harvesting device to the metal sheath of the second phase cable.

[0062] The first and second phases are two-phase metal sheaths that form an energy harvesting circuit after being swapped and installed.

[0063] In this step, the energy harvesting device is used to establish an electrical connection with the first-phase cable metal sheath and the second-phase cable metal sheath, and to introduce the induced electromotive force between the two phase metal sheaths into the subsequent rectification and isolation conversion link. The first input terminal is the interface for the energy harvesting device to connect to the first-phase cable metal sheath, and the second input terminal is the interface for the energy harvesting device to connect to the second-phase cable metal sheath. Together, they constitute the input side of the energy harvesting circuit. The first-phase cable metal sheath and the second-phase cable metal sheath correspond to the two-phase metal sheaths in the single-core cable system, and after being swapped and installed, they form a circuit that can be bridged by the energy harvesting device. In specific implementation, first, the two-phase metal sheaths participating in energy harvesting in the single-core high-voltage cable system are identified, and it is confirmed that the two-phase metal sheaths have been adjusted to form an energy harvesting circuit through the corresponding connection relationship. After the circuit confirmation is completed, a connection structure matching the metal sheath is set on the input side of the energy harvesting device. The connection structure can be a cable sheath lead-out terminal, a crimp terminal, a bolted connector, or a conductive clamp, so that the first input terminal is reliably connected to the first-phase cable metal sheath, and the second input terminal is reliably connected to the second-phase cable metal sheath. To ensure a stable connection, the connecting conductors are insulated wires and insulated from the energy harvesting device housing. Fasteners are installed at the connection points, and the contact surfaces are cleaned to ensure continuous input of the sheath's induced electromotive force into the energy harvesting device. After connection, the first and second input terminals are at different potential points of the two-phase metal sheaths, allowing the energy harvesting device to bridge the two-phase metal sheaths and connect to the energy harvesting circuit. In one possible embodiment, the energy harvesting device is installed in a cable grounding box, cross-connection box, or a closed cavity adjacent to the sheath lead-out end. The input connection length is controlled within the range that meets insulation distance and installation layout requirements to reduce the impact of additional impedance on the energy harvesting process. Based on the above analysis, this step, by directly bridging the energy harvesting device between the two-phase metal sheaths that form the energy harvesting circuit after swapping installations, establishes the energy harvesting path on the induced electromotive force between the two-phase metal sheaths, rather than connecting it in series with the original sheath grounding branch. Therefore, it can provide input conditions for subsequent energy harvesting without changing the existing basic grounding relationship of the metal sheaths. It should be understood that the above example is merely illustrative and not limiting.

[0064] S102: Obtain the induced electromotive force between the two-phase metal sheaths through an energy harvesting device.

[0065] In this step, the induced electromotive force (EMF) is the EMF induced on the metal sheath by the alternating magnetic field generated by the load current in the conductor during the operation of a single-core cable. This induced EMF acts as a voltage source between the metal sheaths of the first and second phases of the cable, which can be utilized by the energy harvesting device. After the energy harvesting device completes the electrical connection at the first and second input terminals, its input circuit directly receives the induced EMF between the two phase metal sheaths and uses this induced EMF as the raw input for subsequent energy conversion. In specific implementation, the energy harvesting device can perform adaptation processing on the input induced EMF to allow it to enter the subsequent processing link. The energy harvesting device can acquire the induced EMF by directly introducing the AC voltage between the first and second input terminals, or by connecting a sampling branch in parallel at the input terminal to detect changes in the amplitude and polarity of the input voltage before sending it to the power processing branch. In actual operation, as the current in the cable core changes, the amplitude of the induced electromotive force (EMF) between the two phase metal sheaths changes accordingly. The energy harvesting device continuously receives this changing voltage on the input side and maintains its conduction relationship with the subsequent rectifier circuit, thus forming a continuous energy harvesting process. For example, the induced EMF can be an AC voltage generated under power frequency conditions, with a frequency consistent with the power system operating frequency. The energy harvesting device directly receives this AC voltage through a dual-ended input method, without the need for additional external magnetic coupling components. If the input voltage is lower than the subsequent stage's operating threshold, the energy harvesting device remains in a standby state; when the induced EMF reaches the starting level required for rectification and isolation conversion, the input energy is sent to the subsequent processing stage. Based on the above analysis, the core of this step lies in utilizing the induced EMF originally present between the two phase metal sheaths as an energy source. The energy harvesting object directly corresponds to the electrical characteristics of the metal sheath itself, reducing the matching deviation introduced by additional coupling components and providing a clear and continuous input basis for the subsequent energy conversion link. In one possible embodiment, the energy harvesting device can determine whether the induced electromotive force is within the normal energy harvesting range by input sampling results. When the input fluctuation is large, the subsequent energy storage capacitor helps maintain short-term power supply continuity. It should be understood that the above example is merely illustrative and not limiting.

[0066] S103: Converts the induced electromotive force into pulsating direct current through rectification.

[0067] In this step, rectification converts the AC induced electromotive force obtained between the two-phase metal sheaths into unidirectional output electrical energy, resulting in pulsating direct current. Rectification can be implemented by a rectifier circuit, ensuring the input AC voltage releases energy to the next stage in a predetermined direction. The pulsating direct current, after rectification, maintains a consistent current direction but still exhibits periodic ripple, serving as the input power for the isolation conversion process. Specifically, the induced electromotive force output from the first and second input terminals is connected to the input terminal of the rectifier circuit, and the output terminal of the rectifier circuit is connected to the subsequent processing node. Considering the potential polarity changes or amplitude fluctuations of the sheath induced voltage during operation, the rectifier circuit can adjust the conduction path to ensure the next stage always receives an input with a fixed polarity. To adapt to the field operating environment, the withstand voltage and conduction capability of the devices in the rectifier circuit are configured based on the induced voltage that may occur between the two-phase metal sheaths. Based on the above analysis, this step converts the induced electromotive force from AC to a pulsating DC form that can be processed subsequently through a rectifier circuit. This maintains the continuous direction of energy transfer and provides a fixed polarity input condition for the isolation converter circuit. This processing link eliminates the need for subsequent stages to directly withstand AC polarity changes, facilitating the use of an isolation converter topology to achieve stable output. It should be understood that the above example is merely illustrative and not limiting.

[0068] S104: Converts pulsating DC power into stable DC power through isolation transformation and outputs it to the load, so as to provide stable power to the load while forming electrical isolation between the preset potential of the metal sheath and the load side.

[0069] The preset potential is the ground potential of the metal sheath, with a maximum value of 300V. The isolation withstand voltage level of the isolation transformation process is configured to be greater than the maximum value of the preset potential.

[0070] Optionally, the maximum phase-to-phase voltage is 519.6V.ac.rms; the maximum phase-to-ground voltage is 300V.ac.rms.

[0071] In this step, the isolation conversion process is used to transform the voltage, transfer energy, and isolate the input and output of the pulsating DC power obtained from the rectification. The result is a stable DC power supply usable by the load. Electrical isolation in the isolation conversion process means that there is no direct conductive path between the input and output sides. Energy is transferred across the isolation boundary through isolation, preventing any high voltage potential on the metal sheath side from being directly conducted to the load side. In practice, the pulsating DC power is connected to the input of the isolation converter circuit, and after isolation transfer and output processing, it forms a stable DC power supply. A corresponding output processing unit can be set at the output end to reduce the impact of load fluctuations on the output voltage. The output parameters are configured according to the load requirements to output stable DC power to the load. Since the input side is directly connected between the two phase metal sheaths, and the output side serves the load, the insulation level and creepage distance in the isolation conversion are configured based on the potential conditions that the metal sheath side may withstand, ensuring that the insulation strength between the input and output meets the requirements of field operation. After a stable DC current is generated, it is led out from the output terminal of the energy harvesting device to the load terminal. The load-side reference ground is isolated from the potential of the metal sheath side, and the load only receives the isolated energy and does not receive the high potential of the input side. Based on the above analysis, this step simultaneously completes energy conditioning and insulation isolation through an isolated conversion link, converting the induced energy introduced by the two-phase metal sheath into a voltage-controllable DC output, and establishing an electrical isolation relationship between the high potential of the metal sheath and the load side, thereby enabling low-voltage loads to be directly powered by the induced energy of the sheath. It should be understood that the above example is only for demonstration and is not limiting.

[0072] Based on the above analysis, this application provides an energy harvesting method based on the metal sheath of a cable, including electrically connecting the first input terminal of the energy harvesting device to the metal sheath of the first phase cable and electrically connecting the second input terminal of the energy harvesting device to the metal sheath of the second phase cable, wherein the first phase and the second phase are two-phase metal sheaths that are swapped to form an energy harvesting circuit; obtaining the induced electromotive force between the two-phase metal sheaths through the energy harvesting device; converting the induced electromotive force into pulsating DC power through rectification; converting the pulsating DC power into stable DC power through isolation conversion and outputting it to the load, so as to provide stable power to the load while forming electrical isolation between the preset potential of the metal sheath and the load side.

[0073] In this embodiment, the energy harvesting device is connected across the two-phase metal sheaths that form the energy harvesting circuit after swapping installations. It directly obtains the induced electromotive force between the two phase metal sheaths and outputs a stable DC power through a rectifier link and an isolation conversion link. This ensures that the energy harvesting process does not require changing the original sheath grounding branch conduction relationship, and the output side is separated from the metal sheath side by an isolation structure. Therefore, it is possible to stably extract the induced energy from the sheath and supply power to the load in the operating environment of a single-core high-voltage cable with a metal sheath, while limiting the high potential on the metal sheath side to the input side and preventing it from being transmitted to the low-voltage load side, thus meeting the requirement of simultaneous on-site energy harvesting and electrical isolation.

[0074] The energy harvesting method based on the metal sheath of a cable provided in this application connects the first and second input terminals of the energy harvesting device to the metal sheaths of two-phase cables that form an energy harvesting circuit after being swapped, and obtains the induced electromotive force between the two-phase metal sheaths. This allows for direct energy harvesting based on the induced energy of the metal sheath itself, avoiding additional series connection effects on the original grounding circuit, thereby improving the compatibility of the energy harvesting scheme with the grounding system of a single-core high-voltage cable. By rectifying the induced electromotive force into pulsating DC power and further isolating and converting it into stable DC power for output to the load, the induced energy of the sheath can be effectively rectified, stabilized, and isolated for power supply. This provides stable power to the load while reducing the risk of high-voltage potential from the metal sheath being conducted to the load side, thus improving overall electrical safety.

[0075] In one possible implementation, the first and second phases are configured as a two-phase metal sheath that forms an energy harvesting circuit after being interchanged, including:

[0076] Keep the original grounding method of two of the metal sheaths unchanged;

[0077] After swapping the positions of the grounding terminal and the floating terminal of the remaining phase metal sheath, grounding is performed to eliminate the floating state and to form an energy extraction circuit between the two phase metal sheaths.

[0078] In practical implementation, one phase of the two-phase metallic sheath maintains its original single-ended grounding or cross-interconnected grounding configuration, with the connection point, grounding lead, and grounding clamp remaining unchanged. The other phase metallic sheath swaps its original grounding end with its original suspended end, ensuring the original suspended end is reliably connected to the grounding grid via a grounding wire, grounding busbar, or detachable grounding terminal, thus transforming the original grounding end into a suspended mating end. This swapping installation can be accomplished using bolt crimping, wire lug crimping, or pluggable terminal structures. The selected structure should match the cable sheath material to ensure stable contact resistance. In practical applications, other models of this component can also be selected; this application embodiment does not limit this. Through the above-mentioned terminal swapping, an induced electromotive force path is formed between the two-phase metallic sheaths, which can be used for inductive energy harvesting.

[0079] The structure operates by swapping the terminals of the remaining phase while maintaining the original grounding relationship of the two phases. This changes the floating ground state to an effective grounded state, preventing the sheath from remaining suspended and establishing a circuit between the two metal sheaths for energy harvesting. Thus, the energy harvesting device can directly extract energy based on the induced electromotive force between the two metal sheaths, providing input for subsequent rectification and isolation conversion.

[0080] With this structure, the existing grounding relationship of the cable's metal sheath is preserved, the floating state is eliminated, the induced energy between the two phase metal sheaths can be stably extracted, and the electrical isolation between the sheath side and the load side can still be maintained, thereby meeting the requirements of safe grounding and stable energy extraction of the sheath.

[0081] In one possible implementation, the induced electromotive force between the two phase metal sheaths is obtained by an energy harvesting device, including: using the induced electromotive force generated on the two phase metal sheaths by the cable operating current as an energy source, wherein the magnitude of the induced electromotive force is positively correlated with the cable operating current and the mutual impedance.

[0082] After the input terminal of the energy harvesting device is electrically connected to the two-phase metal sheath, it can directly use the induced electromotive force generated by the working current on the sheath as the input energy. The induced electromotive force increases with the increase of the cable working current and with the increase of mutual impedance.

[0083] In practical applications, the energy harvesting device can be configured with an input interface adapted to the two-phase metal sheath. After the input interface is connected to the sheath, the induced electromotive force formed between the two-phase metal sheath is introduced into the subsequent rectification and isolation conversion circuit. This energy harvesting device may include a high-voltage resistant insulating shell, lead terminals adapted to the sheath potential, and an input network for voltage sampling. The input network adopts a high-impedance sampling structure to reduce the impact on the original potential distribution of the sheath. The induced electromotive force is led out through the input network and enters the rectification unit. The rectification unit can adopt a diode bridge rectification structure to convert AC or pulsating components into pulsating DC, which is then output as stable DC by the isolation conversion unit. In practical applications, other models of this component can also be selected; this application embodiment does not limit this.

[0084] The working principle of this method is that when the cable load current passes through the conductor, an induced electromotive force (EMF) related to the cable's operating current and mutual impedance is formed on the two-phase metallic sheath. The energy harvesting device directly acquires this induced EMF and supplies energy to the subsequent circuit, thereby converting the existing electromagnetic energy on the sheath side into usable electrical energy. Since the energy source is directly taken from the sheath's induced EMF, the energy harvesting process is compatible with the original relationship of the sheath grounding circuit, enabling stable energy harvesting and electrical isolation to coexist.

[0085] With this implementation method, the energy harvesting device uses the existing induced electromotive force of the sheath as the energy source. The energy harvesting target is clear and consistent with the cable's operating state, so it can obtain corresponding input electrical energy as the cable's operating current changes. At the same time, based on the correspondence between mutual impedance and induced electromotive force, the energy harvesting output can be kept correlated with the cable's operating condition, improving the consistency and feasibility of energy harvesting.

[0086] In one possible implementation, the induced electromotive force is rectified and converted into pulsating direct current, including: rectifying the induced electromotive force using a rectifier bridge to obtain pulsating direct current; and filtering the pulsating direct current using a capacitor.

[0087] The rectifier bridge can adopt a bridge topology composed of four rectifier devices. These devices can be diodes, Schottky diodes, or other devices suitable for low-voltage rectification. In practical applications, other models can also be selected, and this application embodiment does not limit this choice. The capacitor can be one or more combinations of electrolytic capacitors and film capacitors to adapt to different induced electromotive force amplitudes and load input characteristics. In practical applications, other models can also be selected, and this application embodiment does not limit this choice.

[0088] In implementation, the induced electromotive force (EMF) is first input to the AC input terminal of the rectifier bridge. The rectifier bridge maintains the same current direction at its output terminal as the polarity of the induced EMF changes, thus forming a pulsating DC current. This pulsating DC current is then balanced by a capacitor to reduce voltage fluctuations at the output terminal, allowing the subsequent isolation converter circuit to obtain a more stable DC input. The rectifier bridge and capacitor can be integrated into the front-end power processing module of the energy harvesting device, connected by short wires or printed circuit board traces to reduce the impact of parasitic parameters on rectification and filtering effects.

[0089] Through the above structure, the induced electromotive force can first achieve polarity unification through a rectifier bridge, and then achieve ripple suppression through a capacitor, so that the output power form is transformed from AC to pulsating DC suitable for subsequent processing. This allows the subsequent isolation conversion process to obtain a stable input basis and reduces the impact of input fluctuations on the continuity of power supply to the load.

[0090] In one possible implementation, the pulsating DC power is converted into stable DC power through isolation conversion and output to the load, including: inputting the pulsating DC power to a flyback converter, which is used to achieve electrical isolation through high-frequency transformation; grounding the output terminal of the flyback converter to isolate the high voltage potential of the metal sheath; setting the output voltage of the flyback converter according to the load requirements, and outputting stable DC power to the load.

[0091] In this embodiment, the pulsating DC power is rectified and filtered before being fed into the input terminal of the flyback converter. Under the action of high-frequency switching, the flyback converter couples the input energy to the secondary side and forms a stable DC power output with a set voltage through the transformation ratio and feedback adjustment. After the output terminal is grounded, the secondary side is isolated from the high-voltage side of the metal sheath. The load only receives the regulated low-voltage stable DC power, thereby realizing the integrated processing of energy conversion, isolation transmission and potential constraint.

[0092] By adopting the above method, the pulsating DC power can be converted into stable DC power without disrupting the potential control relationship of the metal sheath. Electrical isolation is formed between the output side and the high-voltage sheath side. The power supply voltage at the load end can be set according to actual needs, thereby meeting the power supply requirements of monitoring equipment or communication equipment and reducing the risk of high-voltage potential being conducted to the load side.

[0093] In one possible implementation, the following is also included: setting an overvoltage protection circuit on the primary side of the flyback converter, the overvoltage protection circuit including a circuit breaker and a sheath protector; collecting the input voltage on the primary side of the flyback converter, and triggering the circuit breaker to trip when the input voltage exceeds a preset threshold.

[0094] In practical implementation, the circuit breaker can be an electromagnetic circuit breaker, a DC circuit breaker, or a protective switch with a tripping mechanism. Its contacts are connected in series in the power supply circuit on the primary side of the flyback converter, enabling it to quickly disconnect the circuit after the control coil or tripping unit receives an over-threshold signal. The sheath protector can be composed of a zinc oxide varistor, a surge absorption unit, or an overvoltage clamping unit, and is installed in the same protection branch as the circuit breaker to absorb and limit transient overvoltages. Input voltage acquisition can be achieved through a voltage divider network, an isolated sampling module, or a Hall voltage sensor. The resistance range of the voltage divider network can be configured according to the primary side voltage level. The Hall voltage sensor has isolated sampling characteristics, which facilitates improved detection safety. In practical applications, other models of this component can also be selected, and this application embodiment does not limit this.

[0095] During operation, the voltage signal on the primary side of the flyback converter is acquired in real time and sent to the comparison unit. When the voltage value does not exceed the preset threshold, the circuit breaker remains on, and the flyback converter operates normally. When the voltage value exceeds the preset threshold, the overvoltage protection circuit outputs a trip signal, and the circuit breaker quickly disconnects the primary side input. At the same time, the sheath protector clamps the accompanying overvoltage, thereby maintaining a controlled state between the primary side and the downstream load. With this structure, energy input can be promptly disconnected when the primary side voltage abnormally rises, and sheath-related overvoltages can be limited, keeping the flyback converter and its downstream load in a protected state, thus improving the operational safety and electrical isolation reliability of the sheath energy harvesting system.

[0096] In one possible implementation, the method further includes: acquiring the output voltage at the output terminal of the flyback converter; comparing the output voltage with a reference voltage to obtain a deviation value; calculating the duty cycle based on the deviation value using proportional-integral control; and adjusting the output of the flyback converter according to the duty cycle to stabilize the output voltage.

[0097] In a specific implementation, the output of the flyback converter is connected to the control circuit via a sampling circuit. The sampling circuit can use a voltage divider resistor network to obtain the output voltage and input the sampled signal to the controller. The controller can be a microcontroller, digital signal processor, or analog control chip. In practical applications, other models can also be selected, and this embodiment does not limit this. The controller compares the sampled output voltage with a pre-stored or externally set reference voltage, obtains the deviation value, performs proportional-integral calculation, and then outputs the corresponding duty cycle adjustment signal. This adjustment signal acts on the switching transistor drive terminal of the flyback converter, causing the switching transistor's on-time and off-time to change according to the calculation result, thereby changing the energy transfer magnitude at the output terminal and performing closed-loop correction of the output voltage.

[0098] During operation, when changes in load current cause output voltage fluctuations, the sampling circuit acquires the output voltage in real time and feeds it back to the controller. The controller adjusts the duty cycle based on the deviation value, thereby changing the output power of the flyback converter to gradually approach the reference voltage and maintain stability. This closed-loop regulation method enables the flyback converter to output a relatively constant and stable DC voltage under different load conditions.

[0099] By employing the aforementioned output sampling, comparison, and proportional-integral control methods, the flyback converter can continuously correct for load changes and input fluctuations, limiting the fluctuation range of the output voltage, obtaining a more stable supply voltage at the load end, and ensuring consistency of the isolated converter output after energy extraction.

[0100] The embodiments of this application can be applied to single-core cable tunnel systems in urban high-voltage power grids. For example, in scenarios where single-core cables of voltage level of 35kV and above are laid along the tunnel and the cables are laid in a triangular pattern, the induced electromotive force on the metal sheath of the three-phase cable is used to extract energy to power monitoring equipment such as temperature and humidity sensors and video monitoring terminals in the tunnel.

[0101] Before introducing the specific embodiments of this application, the existing related technologies and the improvement principles on which this application is based will be explained. The power extraction device of the existing cable sheath grounding system is as follows: Figure 2 As shown, Figure 2 This diagram illustrates the application of the energy harvesting device for a conventional cable sheath grounding system when used for single-end grounding. This design alters the existing grounding topology; when applied to single-end grounding, the cable core of that phase is in a "floating" state, posing a safety hazard. Figure 2As can be seen from the topology shown, one end of the C-phase metal layer is suspended, and the other end is grounded through the sheath protector. Furthermore, the original topology does not have equipment to isolate the DC end, and the unsafe potential at the cable end has the risk of being conducted to the DC end equipment.

[0102] In addition to the above Figure 2 In addition to the solution shown, there is another existing technology where the high-voltage cable inductive power supply requires an external energy extraction coil to directly extract power from the power cable core. This is one of the extended applications of "current transformers". Its energy extraction method is not from the cable sheath, which is different from the technical concept of this case.

[0103] This technical solution is applied to grounding scenarios involving the metallic sheath of single-core power cables. The original single-end grounding method for the metallic sheath of single-core power cables is as follows: Figure 3 As shown, Figure 3 This is a schematic diagram of a single-ended grounding system using existing technology. Based on the traditional single-ended grounding system, inverting phase B will yield the following result: Figure 4 The metal sheath grounding method shown is as follows: Figure 4 The diagram provided in this application illustrates a single-ended phase-inverting grounding method that strictly ensures there is no "floating ground" situation. According to... Figure 4 It can be obtained as follows Figure 5 The diagram shown illustrates a single-ended phase-inverting grounding impedance connection. Figure 5 This is a schematic diagram of a single-ended phase-inverting grounding impedance connection provided in this application. As can be seen from this diagram, when drawing power from phases A and C, the energy extraction current does not need to flow through the ground grid. Therefore, an energy extraction circuit can be constructed using phases A and C, from which the following can be obtained: Figure 6 The diagram shown is of a single-ended phase-inverting grounded power extraction circuit. Figure 6 The circuit diagram for single-ended phase-inverting grounding energy extraction provided in this application. Figure 7 The power cable location diagram provided in this application is used to illustrate the relative positional relationship of three-phase cables when laid in a triangular or parallel configuration. The relative position of any two phase cores determines the magnitude of the induced electromotive force between the sheaths, which in turn affects the energy extraction efficiency.

[0104] In a three-phase cable, two phases are selected as the metal sheaths corresponding to the energy extraction circuit, and the grounding arrangement of the sheaths is adjusted first. During implementation, the original grounding method of two phase metal sheaths remains unchanged, and the grounding terminal and the floating terminal of the remaining phase metal sheath are interchanged before grounding. Taking the original single-ended grounding system in a 35kV cable tunnel of a certain urban power grid as an example, the grounding terminal and the floating terminal of phase B metal sheath can be interchanged. While retaining the original grounding method of the other two phases, the floating state of this phase sheath is eliminated, and an energy extraction circuit is formed between the two phase metal sheaths after the interchange.

[0105] After the above grounding arrangement adjustment is completed, the first input terminal of the energy harvesting device is electrically connected to the metal sheath of the first phase cable, and the second input terminal of the energy harvesting device is electrically connected to the metal sheath of the second phase cable, so that the energy harvesting device is connected across the two phase metal sheaths. Taking the metal sheaths of phases A and C as the energy harvesting circuit as an example, the energy harvesting device can be connected in parallel between the metal sheaths of phases A and C, using the induced electromotive force generated on the two phase metal sheaths by the cable operating current as the energy source. The magnitude of this induced electromotive force varies with the cable operating current and mutual impedance. Under the condition of triangular laying, the induced voltage can also be combined with the parasitic capacitance energy of the sheath to be input into the energy harvesting device, providing input voltage for subsequent power conversion in the scenario where monitoring equipment in the tunnel originally relied on external power supply.

[0106] After receiving the induced electromotive force between the two phases of the metal sheath, the energy harvesting device first inputs the induced electromotive force into a rectifier bridge for rectification to obtain pulsating DC power. Then, a capacitor filters the pulsating DC power. Taking the induced sinusoidal wave output between phases A and C of the metal sheath as an example, the rectifier bridge converts it into pulsating DC power, and the filter capacitor smooths the pulsating DC power. The filtered power is sent to the primary side of the flyback converter, where the flyback converter achieves electrical isolation between the primary and secondary sides through high-frequency transformation, converting the pulsating DC power into stable DC power. The output terminal of the flyback converter is grounded to isolate the high-voltage potential carried by the metal sheath. The output voltage of the flyback converter is set according to the load requirements, outputting stable DC power to the load, providing DC power to the temperature and humidity sensors and video monitoring terminals inside the tunnel.

[0107] This embodiment also includes an overvoltage protection circuit on the primary side of the flyback converter. The overvoltage protection circuit includes a circuit breaker and a sheath protector, and collects the input voltage on the primary side of the flyback converter. In cable tunnel applications, overvoltage protection devices can be configured according to the condition that the induced electromotive force amplitude does not exceed 300V. For example, a 690V molded case circuit breaker can be selected as the circuit breaker, and an LHQ-35 sheath protector can be configured to work in conjunction with the primary side. When the input voltage on the primary side is detected to exceed a preset threshold, the circuit breaker is controlled to trip, and the sheath protector limits the overvoltage of the metallic sheath to suppress the abnormal voltage from being conducted to subsequent stages.

[0108] Simultaneously, the output voltage of the flyback converter is acquired, compared with a reference voltage to obtain the deviation value, and then the duty cycle is calculated using proportional-integral control based on this deviation value. The switching operation of the flyback converter is then adjusted according to the duty cycle to maintain the set DC voltage on the output side. Its control loop is as follows: Figure 8 As shown, Figure 8The control loop diagram provided in this application is as follows. During the operation of urban power grid cable tunnels, when cable load fluctuations cause changes in the induced electromotive force between the two-phase metal sheaths, which in turn leads to changes in the primary side input voltage Uin, the control loop monitors the difference between the output voltage Uo and the reference voltage in real time. It updates the duty cycle through the PI controller, drives the switching devices of the flyback converter to adjust their operating states, and thus continuously outputs a set stable DC voltage to the monitoring equipment.

[0109] Simultaneously, the output voltage of the flyback converter is acquired, compared with the reference voltage to obtain the deviation value, and then the duty cycle is calculated through proportional-integral control based on this deviation value. The switching operation of the flyback converter is adjusted according to the duty cycle to maintain the set DC voltage on the output side. During the operation of urban power grid cable tunnels, when cable load fluctuations cause changes in the induced electromotive force between the two-phase metal sheaths, leading to changes in the primary side input voltage Uin, the control loop monitors the difference between the output voltage Uo and the reference voltage in real time. The duty cycle is updated through the PI controller, driving the switching devices of the flyback converter to adjust their operating state, thereby continuously outputting the set stable DC voltage to the monitoring equipment.

[0110] The energy harvesting method based on the metal sheath of a cable provided in this application connects the first and second input terminals of the energy harvesting device to the metal sheaths of two-phase cables that form an energy harvesting circuit after being swapped, and obtains the induced electromotive force between the two-phase metal sheaths. This allows for direct energy harvesting based on the induced energy of the metal sheath itself, avoiding additional series connection effects on the original grounding circuit, thereby improving the compatibility of the energy harvesting scheme with the grounding system of a single-core high-voltage cable. By rectifying the induced electromotive force into pulsating DC power and further isolating and converting it into stable DC power for output to the load, the induced energy of the sheath can be effectively rectified, stabilized, and isolated for power supply. This provides stable power to the load while reducing the risk of high-voltage potential from the metal sheath being conducted to the load side, thus improving overall electrical safety.

[0111] Figure 9 A schematic diagram of the energy harvesting device based on the metal sheath of a cable provided in this application is shown below. Figure 9 As shown, the energy harvesting device 40 based on the metal sheath of a cable provided in this embodiment includes:

[0112] The connection module 401 is used to electrically connect the first input terminal of the energy harvesting device to the metal sheath of the first phase cable, and to electrically connect the second input terminal of the energy harvesting device to the metal sheath of the second phase cable, wherein the first phase and the second phase are two metal sheaths that form an energy harvesting circuit after being swapped.

[0113] The acquisition module 402 is used to acquire the induced electromotive force between the two phase metal sheaths through the energy harvesting device;

[0114] Conversion module 403 is used to convert induced electromotive force into pulsating direct current through rectification;

[0115] Output module 404 is used to convert pulsating DC power into stable DC power through isolation transformation and output it to the load. This provides stable power to the load while forming electrical isolation between the preset potential of the metal sheath and the load side. The preset potential is the potential of the metal sheath to ground, with a maximum value of 300V. The isolation withstand voltage level of the isolation transformation process is configured to be greater than the maximum value of the preset potential.

[0116] In one possible implementation, the connection module 401 is used to keep the original grounding method of two of the metal sheaths unchanged; and to ground the remaining metal sheath after swapping the positions of the grounding terminal and the floating terminal, so as to eliminate the floating state and form an energy harvesting loop between the two metal sheaths.

[0117] In one possible implementation, the acquisition module 402 is used to utilize the induced electromotive force generated on the two-phase metal sheath by the cable operating current as an energy source, wherein the magnitude of the induced electromotive force is positively correlated with the cable operating current and the mutual impedance.

[0118] In one possible implementation, the conversion module 403 is used to rectify the induced electromotive force using a rectifier bridge to obtain pulsating DC power; and to filter the pulsating DC power using a capacitor.

[0119] In one possible implementation, output module 404 is used to input pulsating DC power to flyback converter, which is used to achieve electrical isolation through high-frequency transformation.

[0120] Ground the output of the flyback converter to isolate the high voltage potential of the metal sheath;

[0121] The output voltage of the flyback converter is set according to the load requirements, and a stable DC power is output to the load.

[0122] In one possible implementation, the output module 404 is used to set an overvoltage protection circuit on the primary side of the flyback converter. The overvoltage protection circuit includes a circuit breaker and a sheath protector.

[0123] The input voltage on the primary side of the flyback converter is collected. When the input voltage exceeds a preset threshold, the circuit breaker is triggered to trip.

[0124] In one possible implementation, the output module 404 is used to acquire the output voltage at the output terminal of the flyback converter;

[0125] The output voltage is compared with the reference voltage to obtain the deviation value;

[0126] The duty cycle is calculated based on the deviation value using proportional-integral control, and the output of the flyback converter is adjusted according to the duty cycle to stabilize the output voltage.

[0127] The energy harvesting device based on the metal sheath of the cable provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0128] Figure 10 This is a schematic diagram of the energy harvesting device based on the metal sheath of a cable provided in this application. Figure 10 As shown, the device 50 provided in this embodiment includes at least one processor 501 and a memory 502. Optionally, the device 50 further includes a communication component 503. The processor 501, memory 502, and communication component 503 are connected via a bus.

[0129] In a specific implementation, at least one processor 501 executes computer execution instructions stored in memory 502, causing at least one processor 501 to perform the above-described method.

[0130] The specific implementation process of processor 501 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0131] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0132] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0133] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0134] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0135] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0136] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0137] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0138] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0139] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0140] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0141] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0142] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0143] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for energy harvesting based on the metallic sheath of a cable, characterized in that, include: The first input terminal of the energy harvesting device is electrically connected to the metal sheath of the first phase cable, and the second input terminal of the energy harvesting device is electrically connected to the metal sheath of the second phase cable, wherein the first phase and the second phase are two-phase metal sheaths that form an energy harvesting circuit after being swapped. The induced electromotive force between the two-phase metal sheaths is obtained through the energy harvesting device. The induced electromotive force is rectified and converted into pulsating direct current. The pulsating DC power is converted into stable DC power through isolation transformation and output to the load, so as to provide stable power to the load while forming electrical isolation between the preset potential of the metal sheath and the load side. The preset potential is the ground potential of the metal sheath, and its maximum value is 300V. The isolation withstand voltage level of the isolation transformation process is configured to be greater than the maximum value of the preset potential.

2. The method according to claim 1, characterized in that, The first phase and the second phase are configured as a two-phase metal sheath to form an energy harvesting circuit after being swapped, including: Keep the original grounding method of two of the metal sheaths unchanged; After swapping the positions of the grounding terminal and the floating terminal of the remaining phase metal sheath, grounding is performed to eliminate the floating state and to form an energy harvesting circuit between the two phase metal sheaths.

3. The method according to claim 1, characterized in that, Obtaining the induced electromotive force between the two-phase metal sheaths through the energy harvesting device includes: The induced electromotive force generated on the two-phase metal sheath by the cable operating current is used as an energy source, wherein the magnitude of the induced electromotive force is positively correlated with the cable operating current and the mutual impedance.

4. The method according to claim 1, characterized in that, Converting the induced electromotive force into pulsating direct current through rectification includes: The induced electromotive force is rectified using a rectifier bridge to obtain pulsating direct current; The pulsating DC current is filtered using a capacitor.

5. The method according to claim 1, characterized in that, Converting the pulsating DC power into stable DC power through isolation transformation and outputting it to the load includes: The pulsating DC power is input to the flyback converter, which is used to achieve electrical isolation through high-frequency voltage transformation. The output terminal of the flyback converter is grounded to isolate the high voltage potential of the metal sheath; The output voltage of the flyback converter is set according to the load requirements, and a stable DC power is output to the load.

6. The method according to claim 5, characterized in that, Also includes: An overvoltage protection circuit is provided on the primary side of the flyback converter, and the overvoltage protection circuit includes a circuit breaker and a sheath protector. The input voltage on the primary side of the flyback converter is collected, and when the input voltage exceeds a preset threshold, the circuit breaker is triggered to trip.

7. The method according to claim 5, characterized in that, Also includes: Collect the output voltage at the output terminal of the flyback converter; The output voltage is compared with the reference voltage to obtain the deviation value; The duty cycle is calculated based on the deviation value using proportional-integral control, and the output of the flyback converter is adjusted according to the duty cycle to stabilize the output voltage.

8. An energy harvesting device based on the metallic sheath of a cable, characterized in that, include: A connection module is used to electrically connect the first input terminal of the energy harvesting device to the metal sheath of the first phase cable, and to electrically connect the second input terminal of the energy harvesting device to the metal sheath of the second phase cable, wherein the first phase and the second phase are two-phase metal sheaths that form an energy harvesting circuit after being swapped. The acquisition module is used to acquire the induced electromotive force between the two-phase metal sheaths through the energy harvesting device; A conversion module is used to convert the induced electromotive force into pulsating direct current through rectification. The output module is used to convert the pulsating DC power into stable DC power through isolation transformation and output it to the load, so as to provide stable power to the load while forming electrical isolation between the preset potential of the metal sheath and the load side.

9. An energy harvesting device based on the metallic sheath of a cable, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-7.

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