A power supply system and power supply method for three-core cable

Abstract

The present invention discloses a power supply system and a power supply method for a three-core cable, and relates to the field of electric power technology. The power supply system includes: an electric energy injection device and an inductive power supply device. The electric energy injection device is used to connect with the sheath of the three-core cable and the earth to form a circuit loop, and is used to inject alternating current into the circuit loop; the inductive power supply device is used to sense the alternating current on the sheath of the three-core cable to generate an induced voltage, and is used to transmit the induced voltage to a load. The power supply method includes: step S10, using the electric energy injection device to provide an alternating current to the circuit loop formed by the electric energy injection device, the sheath of the three-core cable, and the earth; step S20, using the inductive power supply device to sense the alternating current on the sheath of the three-core cable to generate an induced voltage, and transmit the induced voltage to a load. The present invention can solve the technical problem that the existing three-core cable cannot draw power.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a power taking system and a power taking method for a three-core cable. Background Art

[0002] 10kV cables usually use three-core cables, with three cores in a single cable, connected to three-phase electricity. The cable online monitoring equipment is installed near the cable line, the cable is buried underground, and the online monitoring equipment is installed underground, so the commonly used solar power supply method cannot be used.

[0003] The power frequency current flows in the cable, so the online monitoring device along the cable is usually powered by the power frequency current induction of the core. This method is feasible for single-core cables. However, for three-core turnkey cables, the three-phase current is basically offset after synthesis outside the cable sheath, and power cannot be inducted. Summary of the invention

[0004] The embodiments of the present invention provide a power supply system and a power supply method for a three-core cable, so as to solve the technical problem that the three-core cable cannot supply power in the related art.

[0005] In a first aspect, an embodiment of the present invention provides a power supply system for a three-core cable, the power supply system comprising:

[0006] An electric energy injection device, the electric energy injection device is used to connect with the sheath of the three-core cable and the ground to form a circuit loop, and is used to inject alternating current into the circuit loop;

[0007] An inductive power extraction device is used to induce the alternating current on the sheath of the three-core cable to generate an induced voltage, and is used to transmit the induced voltage to a load.

[0008] In some embodiments, the electric energy injection device comprises:

[0009] DC power supply;

[0010] An inverter circuit is connected to the DC power supply, and is used for inverting the direct current of the DC power supply into alternating current and then outputting it to the sheath of the three-core cable.

[0011] In some embodiments, the electric energy injection device further comprises:

[0012] A coupler is used to couple the alternating current output by the inverter circuit to the sheath of the three-core cable.

[0013] In some embodiments, the coupler is a snap-on magnetic core.

[0014] In some embodiments, the electric energy injection device further comprises:

[0015] A controllable switch, wherein the controllable switch is arranged between the sheath of the three-core cable and the ground;

[0016] The acquisition circuit is used to acquire the voltage of the three-core cable sheath, and is configured as follows: when the voltage of the three-core cable sheath is greater than a preset voltage, the acquisition circuit is also used to control the controllable switch to close so that the three-core cable sheath is short-circuited with the ground, so that the cable sheath is directly grounded.

[0017] In some embodiments, the controllable switch is an electromagnetic relay.

[0018] In some embodiments, the electric energy injection device further comprises:

[0019] AC power supply;

[0020] A rectifier circuit is connected to the AC power supply, and is used for rectifying the alternating current of the AC power supply into direct current and then outputting the direct current to the inverter circuit.

[0021] In some embodiments, the rectifier circuit is a full-bridge rectifier circuit.

[0022] In some embodiments, the inverter circuit is a fully controlled inverter circuit.

[0023] In a second aspect, an embodiment of the present invention provides a method for obtaining power from a three-core cable, the method comprising:

[0024] Use an electric energy injection device to provide alternating current to a circuit loop formed between the three-core cable sheath and the ground;

[0025] An inductive power-taking device is used to sense the alternating current on the sheath of the three-core cable to generate induced power, and the induced power is transmitted to the load.

[0026] The beneficial effects brought about by the technical solution provided by the present invention include:

[0027] The embodiment of the present invention provides a power supply system and power supply method for a three-core cable. One end of the sheath of the three-core cable is grounded, and the other end is connected to an electric energy injection device and then grounded, forming a circuit loop. After the electric energy injection device injects alternating current into the circuit loop, the inductive power supply device senses the alternating current on the sheath of the three-core cable to generate an induced voltage, and transmits the induced voltage to the load to provide electric energy for the load. Therefore, the power supply system and power supply method of the present invention can draw power from a three-core cable and provide it to a cable online monitoring device, thereby solving the technical problem that the existing three-core cable cannot draw power. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic structural diagram of a power supply system for a three-core cable provided in an embodiment of the present invention;

[0030] Figure 2 A schematic structural diagram of a power supply system for a three-core cable provided in an embodiment of the present invention;

[0031] Figure 3 A schematic structural diagram of a power supply system for a three-core cable provided in an embodiment of the present invention;

[0032] Figure 4 A flow chart of a method for obtaining power from a three-core cable provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The embodiment of the present invention provides a power supply system for a three-core cable, which can solve the technical problem that the three-core cable cannot supply power.

[0035] See also Figure 1 As shown, a power extraction system for a three-core cable includes: a power injection device and an inductive power extraction device.

[0036] The power injection device is used to connect with the three-core cable sheath and the ground to form a circuit loop, and is used to transfer alternating current to the circuit loop. The inductive power extraction device is used to induce the alternating current on the three-core cable sheath to generate an induced voltage, and is used to transmit the induced voltage to the load.

[0037] Specifically, see Figure 1As shown, in the power supply system for three-core cables in the embodiment of the present invention, one end of the sheath of the three-core cable is grounded, and the other end is connected to the power injection device and then grounded, forming a circuit loop. After the power injection device injects alternating current into the circuit loop, the inductive power supply device senses the alternating current on the sheath of the three-core cable to generate an induced voltage, and transmits the induced voltage to the load to provide electrical energy to the load, wherein the load is usually a cable online monitoring device. Therefore, the power supply system for three-core cables in the embodiment of the present invention can draw electricity from the three-core cable and provide it to the cable online monitoring device, thereby solving the technical problem that the existing three-core cable cannot draw electricity.

[0038] As an alternative embodiment, see Figure 1 As shown, the electric energy injection device includes: a DC power supply and an inverter circuit. The inverter circuit is connected to the DC power supply, and the inverter circuit is used to invert the direct current of the DC power supply into alternating current and then output it to the three-core cable sheath. Preferably, the inverter circuit is a fully controlled inverter circuit.

[0039] As an alternative embodiment, see Figure 2 As shown, the electric energy injection device further includes: a coupler, the coupler is used to couple the alternating current output by the inverter circuit to the sheath of the three-core cable. Preferably, the coupler is a snap-on magnetic core, and a high-permeability snap-on magnetic core. The use of the coupler does not require the three-core cable sheath to be untied, which is convenient for implementation.

[0040] As an alternative embodiment, see Figure 3 As shown, the electric energy injection device also includes: a controllable switch and a collection circuit. The controllable switch is arranged between the sheath of the three-core cable and the earth. The collection circuit is used to collect the voltage of the sheath of the three-core cable, and is configured as follows: when the voltage of the sheath of the three-core cable is greater than a preset voltage, the collection circuit is also used to control the controllable switch to close so that the sheath of the three-core cable is short-circuited with the earth, so that the cable sheath is directly grounded. Through the controllable switch and the collection circuit, the overvoltage phenomenon of the sheath of the three-core cable can be avoided.

[0041] As an optional implementation, the controllable switch is an electromagnetic relay. Electromagnetic relay is an electronic control device, which has a control system and a controlled system. It is usually used in automatic control circuits. It is actually an "automatic switch" that uses a smaller current and a lower voltage to control a larger current and a higher voltage. Therefore, it plays the role of automatic adjustment, safety protection, and circuit conversion in the circuit.

[0042] As an alternative embodiment, see Figure 1As shown, the electric energy injection device further includes: an AC power supply and a rectifier circuit. The rectifier circuit is connected to the AC power supply, and is used to rectify the alternating current of the AC power supply into direct current and then output it to the inverter circuit. Preferably, the rectifier circuit is a full-bridge rectifier circuit.

[0043] See also Figure 4 As shown, an embodiment of the present invention further provides a method for obtaining power from a three-core cable, the method comprising:

[0044] Step S10, using an electric energy injection device to provide alternating current to a circuit loop formed by the three-core cable sheath and the ground.

[0045] Step S20: using an inductive power extraction device to sense the alternating current on the sheath of the three-core cable to generate induced power, and then transmitting the induced power to the load.

[0046] In the power-drawing method for a three-core cable in an embodiment of the present invention, one end of the sheath of the three-core cable is grounded, and the other end is connected to the power injection device and then grounded, forming a circuit loop. When the power injection device injects alternating current into the circuit loop, the inductive power-drawing device senses the alternating current on the sheath of the three-core cable to generate an induced voltage, and transmits the induced voltage to the load to provide electrical energy for the load. Therefore, the power-drawing method of the present invention can draw electricity from a three-core cable and provide it to a cable online monitoring device, solving the technical problem that the existing three-core cable cannot draw electricity.

[0047] Furthermore, the electric energy injection device comprises: a DC power supply and an inverter circuit. The inverter circuit is connected to the DC power supply, and is used to invert the direct current of the DC power supply into alternating current and then output it to the sheath of the three-core cable. Preferably, the inverter circuit is a fully controlled inverter circuit.

[0048] Furthermore, the electric energy injection device further comprises: a coupler, the coupler being used to couple the alternating current output by the inverter circuit to the sheath of the three-core cable. Preferably, the coupler is a snap-on magnetic core with a high magnetic permeability. The use of the coupler does not require the three-core cable sheath to be untied, which is convenient for implementation.

[0049] Furthermore, the electric energy injection device further includes: a controllable switch and a collection circuit. The controllable switch is arranged between the sheath of the three-core cable and the earth, and the collection circuit is used to collect the voltage of the sheath of the three-core cable, and is configured as follows: when the voltage of the sheath of the three-core cable is greater than a preset voltage, the collection circuit is also used to control the controllable switch to close so that the sheath of the three-core cable is short-circuited with the earth, so that the cable sheath is directly grounded.

[0050] Furthermore, the electric energy injection device further comprises: an AC power supply and a rectifier circuit. The rectifier circuit is connected to the AC power supply, and is used to rectify the alternating current of the AC power supply into direct current and then output it to the inverter circuit. Preferably, the rectifier circuit is a full-bridge rectifier circuit.

[0051] In the description of the present invention, it should be noted that the terms "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, 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 or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0052] It should be noted that, in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0053] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A power supply system for a three-core cable, wherein the three-core cable has three cores inside and a sheath outside, characterized in that: The power taking system comprises: An electric energy injection device, the electric energy injection device is used to connect with the sheath of the three-core cable and the earth to form a circuit loop, and is used to inject alternating current into the circuit loop; the electric energy injection device includes: a DC power supply, an inverter circuit and a coupler, the inverter circuit is connected to the DC power supply, the inverter circuit is used to invert the direct current of the DC power supply into alternating current, and the coupler is used to couple the alternating current output by the inverter circuit to the sheath of the three-core cable; the electric energy injection device also includes: a controllable switch and a collection circuit, the controllable switch is arranged between the sheath of the three-core cable and the earth, the collection circuit is used to collect the voltage of the sheath of the three-core cable, and is configured as follows: when the voltage of the sheath of the three-core cable is greater than a preset voltage, the collection circuit is also used to control the controllable switch to close so that the sheath of the three-core cable is short-circuited with the earth; An inductive power extraction device is used to sense the alternating current on the sheath of the three-core cable to generate an induced voltage, and is used to transmit the induced voltage to the cable online monitoring device.

2. The power supply system for a three-core cable according to claim 1, characterized in that: The coupler is a snap-on magnetic core.

3. The power supply system for three-core cables according to claim 1, characterized in that: The controllable switch is an electromagnetic relay.

4. The power supply system for three-core cables according to claim 1, characterized in that: The electric energy injection device also includes: AC power supply; A rectifier circuit is connected to the AC power supply, and is used for rectifying the alternating current of the AC power supply into direct current and then outputting the direct current to the inverter circuit.

5. The power supply system for three-core cables according to claim 4, characterized in that: The rectifier circuit is a full-bridge rectifier circuit.

6. The power supply system for three-core cables according to claim 1, characterized in that: The inverter circuit is a fully controlled inverter circuit.

7. A method for obtaining electricity from a three-core cable power supply system as claimed in claim 1, characterized in that: The power extraction method comprises: Use an electric energy injection device to provide alternating current to the circuit loop formed by the three-core cable sheath and the ground; An inductive power-taking device is used to induce the alternating current on the sheath of the three-core cable to generate an induced voltage, and the induced voltage is transmitted to the load.

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