CN102780273A - High-voltage wire magnetic field induction energy taking device for high-voltage transmission line online monitoring - Google Patents

Abstract

A high-voltage wire magnetic field induction energy harvesting device for on-line monitoring of high-voltage transmission lines: including a coil (1), a rectifier circuit (2), a switch circuit (3), a control circuit (4) and an energy storage circuit (5), and the coil is set on On the high-voltage wire, the AC current is induced from the high-voltage wire by the principle of electromagnetic induction and sent to the rectifier circuit. The rectifier circuit converts the AC current into a DC current and charges the energy storage circuit. The circuit detects the output voltage of the energy storage circuit, and controls the switch circuit to be turned on and off accordingly, and the energy storage circuit outputs voltage and current. The invention does not reduce the scope of application of the energy harvesting device, and reduces the power consumption of the switching circuit. Since in actual use, the switch circuit is in a conducting state for a long time, the magnetic induction in the coil magnetic core is very low, thus reducing the power consumption of the magnetic core. Since the overall power consumption of the energy harvesting device is reduced, its service life, stability and reliability are greatly improved.

Description

A high-voltage wire magnetic field induction energy harvesting device for on-line monitoring of high-voltage transmission lines

technical field

The invention relates to a wire magnetic field induction energy harvesting device, in particular to a high-voltage wire magnetic field induction energy harvesting device for on-line monitoring of high-voltage transmission lines.

Background technique

With the development of science and technology, various physical parameters of live detection lines are increasingly required in the field of high-voltage transmission lines. A considerable number of devices will be suspended on high-voltage transmission wires to measure physical parameters such as wire temperature and wire sag. Because these monitoring devices need to be installed directly on the high-voltage transmission line, what method to use to power the device is a problem that we need to focus on. At present, the power supply methods that are widely used mainly include solar power supply, battery power supply, magnetic field induction power supply, laser power supply, etc. The working principle of the storage battery is the changing law of mutual conversion between chemical energy and electrical energy. This method has a simple structure and is relatively easy to implement. However, due to the short life of the storage battery, the battery needs to be replaced frequently when used for a long time; for solar power supply, the solar battery uses photoelectricity. The principle of conversion is a device that converts the sun's radiant light into electrical energy through semiconductor materials. At present, solar technology needs to further improve its efficiency, especially in long-term rainy weather, and its endurance and stability cannot be guaranteed; laser energy supply It uses laser or other light sources to transmit light energy from the low potential side to the high potential side through the optical fiber, and then converts the light energy into electrical energy output by a photoelectric conversion device (photoelectric cell). This method has a short life, is expensive, and requires on-site maintenance trouble. Magnetic field induction energy harvesting is to nest a coil on a high-voltage current-carrying wire, and use the principle of electromagnetic induction to induce a current that is proportional to the current amplitude in the high-voltage wire on the coil.

At present, the main problem encountered in magnetic field induction energy harvesting is the saturation of the coil core. Since the current amplitude on the transmission line varies widely, from dozens of amperes to thousands of amperes, if you want the energy-taking coil to obtain enough power when the current of the transmission line is small, and when the current of the transmission line becomes larger , if no measures are taken, the core of the coil will inevitably be saturated. After the magnetic core is saturated, the waveform of the output voltage of the coil is seriously distorted, resulting in a high-amplitude peak, which seriously threatens the safety of the electrical device; and the loss of the magnetic core increases, the heat is severe, and even burned.

Therefore, the key issue of using magnetic field induction for energy harvesting is how to suppress the deep saturation of the energy harvesting core at high currents. In order to prevent core saturation, the following measures are generally adopted:

1) Increase the air gap on the magnetic core of the energy-taking coil to introduce air gap reluctance, reduce the magnetic permeability and increase the saturation current of the magnetic core. Although this method can suppress the saturation of the magnetic core, opening an air gap to the magnetic core will lead to a large starting current of the magnetic field energy harvesting device, resulting in the energy harvesting and power supply device being unable to provide the specified voltage when the current of the transmission line is small; in addition, the coil turns that need to be wound The number increases, and the winding work is troublesome; in addition, during operation, the vibration caused by the outside or the equipment itself may deform the air gap and reduce the reliability of the device. All in all, although it is feasible to use an air gap to suppress the saturation of the magnetic core of the magnetic field energy harvesting device, it is very difficult to implement.

2) Increase the compensation coil. The direction of the magnetic field generated by the compensation coil and the transmission wire is opposite. When the current of the transmission line is large, the output voltage of the energy-taking coil is relatively high, and the control circuit accordingly increases the current of the compensation coil to partially offset the magnetic field generated by the transmission wire, thereby Make sure the coil core is not saturated. This method can effectively suppress the influence of the wide dynamic range change of the primary current on the output voltage of the energy harvesting device, but the control strategy is complicated and the circuit is complicated, which makes the reliability of the device not high.

3) Use components such as triodes and bidirectional thyristors to discharge excess electric energy. For example, as described in Chinese invention patent 201110323678.x, a control circuit is drawn from the output end of the energy harvesting coil to control the triode and bidirectional thyristor connected in parallel to the output end of the energy harvesting coil. When the output voltage of the coil is too large, the bidirectional thyristor is turned on to discharge the current induced by the coil. Transistors, bidirectional thyristors and other components can work stably for a long time only when they are fully turned on or completely turned off. A large amount of power consumption is generated, causing the components to overheat and burn out.

The problem with the control strategy of the energy harvesting device described in Chinese invention patent 201110323678.x is that the control circuit forms an analog voltage feedback, and the strength of the control signal is proportional to the output voltage of the device, that is, the control signal is an analog quantity. Therefore, there is a problem of the strength of the control signal. First, when the current of the transmission line is at a critical value (that is, the output voltage of the coil is near the maximum output voltage value), the control signal output from the control circuit is relatively weak, so that the triac is incomplete. It is turned on and not completely turned off, resulting in huge power consumption, which will soon cause the thyristor to burn out; secondly, because this control strategy forms a negative feedback, in practice, the output voltage of the device will gradually stabilize and the control signal will gradually become stable. In weak cases, especially the output voltage value will continue to change back and forth near the steady-state output voltage value, which will cause the bidirectional thyristor to be neither completely turned on nor completely turned off, and frequent transitions between the on state and the off state will occur. conversion, causing a large amount of power consumption, which burns out.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-voltage wire magnetic field induction energy harvesting device for on-line monitoring of high-voltage transmission lines with stable performance.

The solution of above-mentioned technical problem, the technical scheme that the present invention adopts is as follows:

A high-voltage wire magnetic field induction energy harvesting device for on-line monitoring of high-voltage transmission lines is characterized in that it includes a coil 1, a rectifier circuit 2, a switch circuit 3, a control circuit 4 and an energy storage circuit 5, and the coil 1 is set on a high-voltage wire Above, use the principle of electromagnetic induction to induce AC current from the high-voltage wire and send it to the rectifier circuit. The rectifier circuit converts the AC current into DC current and charges it to the energy storage circuit. The output voltage of the energy storage circuit controls the on and off of the switch circuit accordingly, and the energy storage circuit 5 outputs voltage and current.

The energy-taking coil 1 uses a silicon steel sheet as the magnetic core. The shape of the silicon steel sheet magnetic core is a ring with an inner diameter of 80mm, an outer diameter of 120mm, and a height of 20mm. , The coil is formed by winding 200 turns of enameled wire with a diameter of 1mm on the magnetic core.

The rectifier circuit 2 is a full-wave rectifier circuit composed of four ordinary diodes, the switch circuit 3 is an ordinary switch transistor, its emitter and collector are respectively connected to the output terminal of the rectifier circuit 2, and the base is connected to the control circuit 4 , the control circuit 4 is composed of an ordinary single-chip microcomputer and two voltage dividing resistors connected between the output terminals of the rectifying circuit 2, one end of the single-chip microcomputer is connected to the switch circuit 3, and the other end is connected between the two voltage dividing resistors, and connected in parallel The energy storage circuit 5 between the output terminals of the rectifier circuit 2 is composed of a capacitor and an ordinary diode in series, and voltage and current are output at both ends of the capacitor.

The output voltage of the device is determined between the maximum output voltage U _H and the minimum output voltage U _L , rather than a certain fixed value. The control strategy of the energy-taking device is that when the control circuit 4 detects that the output voltage of the energy storage circuit 5 exceeds the set maximum output voltage U _H , it sends a conduction signal to the switch circuit 3, and the switch circuit is turned on to short-circuit the output of the coil. , the rectifier circuit 2 has no output current, and does not charge the energy storage circuit 5; when the control circuit 4 detects that the output voltage of the energy storage circuit 5 is lower than the set minimum output voltage _UL , it sends a shutdown signal to the switch circuit 3, and the switch The circuit 3 is turned off, and the output current of the coil 1 charges the energy storage circuit 5 through the rectification circuit 2 . This control strategy minimizes the number of actions of the switch circuit 3, thereby reducing the power consumption of the switch circuit 3 due to switching between the on state and the off state.

The control circuit is made up of microprocessor 6 and its peripheral circuits. The microprocessor 6 detects the output voltage of the energy storage circuit, performs automatic threshold comparison diagnosis, and sends out corresponding control signals. Therefore, the control signal is a digital quantity, which can ensure that the switch circuit 3 is in a fully on state or a completely off state, thereby preventing the switch circuit 3 from being burned due to incomplete conduction or incomplete shutdown.

The present invention does not relate to the surge protection problem of the energy harvesting device, and existing surge protection measures can be used in combination with the present invention.

Beneficial effects: the advantage of the patent of the present invention is that the power consumption of the switching circuit is reduced as much as possible without reducing the applicable range of the energy harvesting device (that is, the amplitude range of the current on the transmission wire). Since in actual use, the switch circuit is in a conducting state for a long time, the magnetic induction in the coil magnetic core is very low, thus reducing the power consumption of the magnetic core. Since the overall power consumption of the energy harvesting device is reduced, its service life, stability and reliability are greatly improved.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the present invention;

Fig. 2 is an embodiment of the present invention.

Detailed ways

The embodiment of the high-voltage wire magnetic field induction energy harvesting device for high-voltage transmission line online monitoring of the present invention is shown in Figure 2, including a coil 1, a rectifier circuit 2, a switch circuit 3, a control circuit 4 and an energy storage circuit 5, and the coil 1 is set on the high-voltage wire Above, using the principle of electromagnetic induction to induce AC current from the high-voltage wire and send it to the rectifier circuit 2, the rectifier circuit 2 converts the AC current into a DC current, and charges the energy storage circuit 5, and the switch circuit 3 is connected in parallel to the output end of the rectifier circuit 2; The control circuit 4 detects the output voltage of the energy storage circuit, and accordingly controls the switch circuit to be turned on and off, and the energy storage circuit 5 outputs voltage and current.

The energy-taking coil 1 uses a silicon steel sheet as the magnetic core. The shape of the silicon steel sheet magnetic core is a ring with an inner diameter of 80mm, an outer diameter of 120mm, and a height of 20mm. It is cut into two semicircles from the middle to facilitate clamping on the high-voltage transmission wire. The coil is formed by winding 200 turns of enameled wire with a diameter of 1mm on the magnetic core.

The rectifier circuit 2 is a full-wave rectifier circuit composed of four ordinary diodes, the switch circuit 3 is an ordinary switch triode, its emitter and collector are respectively connected to the output end of the rectifier circuit 2, the base is connected to the control circuit 4, and the control circuit 4. It consists of an ordinary single-chip microcomputer and two voltage dividing resistors connected between the output terminals of the rectifier circuit 2. One end of the single-chip microcomputer is connected to the switch circuit 3, and the other end is connected to the middle of the two voltage dividing resistors, and connected to the rectifying circuit. The energy storage circuit 5 between the output terminals of 2 is composed of a capacitor connected in series with an ordinary diode, and the voltage and current are output at both ends of the capacitor.

When the switching transistor is turned off, the current induced by the coil charges the capacitor through the rectifier circuit; when the switching transistor is turned on, the current induced by the coil is discharged through the switching transistor without charging the capacitor. The capacitor provides power to the electrical device, and its output voltage gradually decreases. When the microcontroller detects that the voltage of the capacitor is lower than _UL , it sends a shutdown signal to the switching transistor; the switching transistor is turned off, and the capacitor begins to charge, and its voltage gradually increases; When the single-chip microcomputer detects that the voltage of the capacitor is higher than U _H , it sends a conduction signal to the switch transistor; the switch transistor is turned on, and the capacitor stops charging.

Claims (2)

1. a ultra-high-tension power transmission line on-line monitoring is with high-voltage conducting wires magnetic field induction energy taking device; It is characterized in that: comprise coil (1), rectification circuit (2), switching circuit (3), control circuit (4) and accumulator (5); Described coil (1) is enclosed within on the high-voltage conducting wires, induces alternating current and delivers to rectification circuit (2), and rectification circuit (2) converts alternating current to direct current; And to (5) road charging of energy storage electricity, switching circuit (3) is connected in parallel on the output of rectification circuit (2); Control circuit (4) detects the output voltage of accumulator (5), the conducting of control switch circuit and shutoff according to this, accumulator (5) output voltage electric current.

2. ultra-high-tension power transmission line on-line monitoring according to claim 1 is with high-voltage conducting wires magnetic field induction energy taking device; It is characterized in that: described rectification circuit (2) is the full-wave rectifying circuit that four general-purpose diodes are formed; Switching circuit (3) is a regular tap triode; Its emitter and collector is connected to the output of rectification circuit (2); Base stage connects control circuit (4), and control circuit (4) is made up of a common single-chip microcomputer and 2 voltage divider resistances being connected between the output of rectification circuit (2), and the end connection switching circuit (3) of single-chip microcomputer, the other end are connected in the middle of 2 divider resistances; And the accumulator (5) that is connected between the output of rectification circuit (2) is composed in series capacitor two ends output voltage electric current by capacitor and diode.

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