A distributed power supply low-current start-up front-end protection device

Abstract

This invention discloses a pre-stage protection device for low-current startup of a distributed power supply, comprising: a high-current surge protection circuit connected to the output of the secondary coil of a CT magnetic ring; an EMC filter circuit connected to the output of the high-current surge protection circuit; a voltage regulator unit connected in parallel with the EMC filter circuit; and an energy release circuit connected to the output of the EMC filter circuit. The high-current surge protection circuit includes a varistor connected in series with a gas discharge tube. This invention, through multi-stage protection circuitry, can eliminate the damage to subsequent circuits caused by rapid changes in grounding current, providing a stable, reliable, and economical technical solution.

Description

Technical Field

[0001] This invention belongs to the field of power systems and relates to a distributed power source low-current power supply system, and more particularly to a distributed power source low-current start-up protection device. Background Technology

[0002] In power systems, improving the health of power equipment requires online and real-time monitoring to enable early warning and maintenance. Real-time online monitoring relies heavily on numerous sensors and measuring devices. Since many power devices are distributed in different locations, such as monitoring cable joints, sensors and monitoring equipment need to be installed near cable grounding boxes along the cable laying route. However, power supplies for these monitoring devices are sometimes difficult to obtain, necessitating the design of a safe, reliable, stable, and economical power source. Our new design solution utilizes battery power and on-site energy harvesting to power the monitoring equipment. On-site energy harvesting is achieved by drawing power from the grounding cable using an inductor. Normally, the current in the grounding cable is around 1A, but sometimes, due to lightning strikes, the current flowing through the grounding cable can reach thousands of amperes. How to prevent damage to downstream circuits from such a large current passing through in a short time becomes a key research focus and challenge. Summary of the Invention

[0003] In view of this, it is necessary to overcome at least one of the above-mentioned defects in the prior art. The present invention provides a distributed power supply low-current startup pre-stage protection device comprising: a high-current surge protection circuit connected to the output of the secondary coil of a CT magnetic ring; an EMC filter circuit connected to the output of the high-current surge protection circuit; a voltage regulator unit connected in parallel with the EMC filter circuit; and an energy release circuit connected to the output of the EMC filter circuit; the high-current surge protection circuit includes a varistor connected in series with a gas discharge tube.

[0004] This technical solution is applicable to a method for providing uninterrupted, stable, and economical power to equipment such as those used for monitoring long-distance power cables. Specifically, it employs an independent power supply and utilizes a CT magnetic ring to collect electrical energy from the grounding wire to provide stable power to the corresponding equipment. Although the current in the grounding wire is typically around 1A, under special circumstances, such as lightning strikes, the current in the grounding wire can change drastically, reaching thousands of amperes. In such cases, without specific protection, such a large current change will inevitably cause significant damage to the corresponding circuit. Therefore, this technical solution eliminates such hazards through multi-level protection circuits and is also an economical and stable technical solution.

[0005] In addition, the distributed power supply low-current start-up pre-stage protection device disclosed in this invention also has the following additional technical features:

[0006] Furthermore, the voltage regulating unit is a Zener diode, such as D2 / D4 in the view.

[0007] Zener diodes have a fast response speed. In order to protect the maximum input voltage of the downstream chip, the regulated value is set at the maximum input voltage V of the downstream chip, which can provide instantaneous protection for the downstream circuit.

[0008] Furthermore, one end of the anti-high current surge circuit is connected to the L output terminal of the CT magnetic ring secondary coil, and the other end is connected to the N output terminal of the CT magnetic ring secondary coil. The two ends of the first varistor are connected to the L output terminal and the N output terminal. One end of the second varistor is connected to the L output terminal, and the second varistor is connected to the N output terminal through the third varistor, and the gas discharge tube is connected in series to ground.

[0009] Furthermore, the anti-high current surge circuit also includes a bidirectional TVS diode whose two ends are connected to the output terminals of the secondary coil of the CT magnetic ring.

[0010] TVS diodes are used to absorb surge power and can withstand reverse voltage surges for a very short time, clamping the voltage between their terminals to a specific voltage to prevent downstream circuits from being impacted. However, in terms of surge current protection, TVS diodes are much less capable than varistors. For example, the main material for current surge protectors is the varistor, and TVS diodes cannot be used. This is because TVS diodes have a small current-carrying capacity while varistors have a large current-carrying capacity when protecting against lightning surges. Varistors should be used for absorbing surge currents / voltages with higher energy, but in terms of response speed, varistors are in the nanosecond range while TVS diodes are in the picosecond range. However, because varistors have a large parasitic capacitance, the leakage current is relatively large. Poor-performing varistors may overheat and spontaneously combust after repeated use. Therefore, in this design, a gas discharge tube is connected in series between the varistors. Since the parasitic capacitance of the gas discharge tube is small, the total capacitance of the series branch is reduced, thereby reducing the leakage current.

[0011] Furthermore, the EMC filter circuit includes a first capacitor connected to the output terminal of the secondary coil of the CT magnetic ring and grounded through a fifth capacitor, a second capacitor connected to the output terminal of the secondary coil of the CT magnetic ring, and a third and a fourth capacitor connected in series with the output terminal of the secondary coil of the CT magnetic ring. One end of the third capacitor is connected to the output terminal of the secondary coil of the CT magnetic ring, and the other end is grounded.

[0012] Since the grounding box is installed on a 110KV three-phase grounding line, it is surrounded by a strong magnetic field environment, which can easily interfere with the downstream circuits, causing instability in circuit operation or even burning out the downstream circuits. After adding an EMC filter, the equipment can effectively pass the electrical fast pulse test, radiated immunity test, conducted sensitivity test and electrostatic discharge test, and its reliability and safety performance are better improved.

[0013] Furthermore, the energy release circuit includes a pre-amplifier and a MOSFET connected in series with the output of the EMC filter circuit. The MOSFET is grounded. The energy release circuit also includes electronic components for boosting the gate voltage of the MOSFET.

[0014] Preferably, the electronic component is a resistor.

[0015] Because the current on the grounding wire is not constant, the rectified voltage will increase as the bus current increases and decrease as the bus current decreases. To protect downstream chips, the rectified voltage must be limited to a specified range. Furthermore, excessive energy output will shorten the lifespan of components. Therefore, an energy discharge circuit is needed to limit excessive energy output. The energy discharge circuit's response speed is relatively slower than that of a Zener diode. When the output voltage of the preceding rectifier circuit is low, the circuit does not operate, and the MOSFET is not conducting. When the voltage is high, current flows through the electronic components to raise the voltage. Once the gate voltage of the MOSFET reaches a specific value, the MOSFET begins to conduct, and excess energy current can be discharged through the power resistor.

[0016] For example, the series-connected preamplifier and MOSFET use four branches, including first to fourth preamplifiers and first to fourth MOSFETs. The electronic component that boosts the gate voltage of the MOSFET is preferably a resistor. Once the MOSFET gate voltage reaches a certain value, the MOSFET begins to conduct, and excess energy current can be discharged through the first to fourth preamplifiers. The energy release circuit also includes a fifth and a sixth resistor with a set specific voltage value. The specific voltage value is:

[0017] .

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is a schematic diagram of the application device according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of a multi-level protection circuit according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the anti-high current surge circuit according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the EMC filter circuit according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the energy discharge circuit according to an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of a switching circuit with two multi-level protection circuits according to an embodiment of the present invention. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "back", "inner", "outer", "horizontal", "vertical", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "connection," "linking," "joining," and "fitting" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium; "fitting" can refer to the fit between surfaces, or the fit between a point and a surface or a line and a surface, and also includes the fit between a hole and a shaft. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0029] The alignment device for bonding steel sheets of the present invention will now be described with reference to the accompanying drawings, wherein... Figure 1 This is a schematic diagram of the application device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a multi-level protection circuit according to an embodiment of the present invention; Figure 3This is a schematic diagram of the anti-high current surge circuit according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the EMC filter circuit according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the energy discharge circuit according to an embodiment of the present invention.

[0030] The application scenarios in this case are as follows:

[0031] High-voltage cables and online monitoring are installed inside the power tunnel. Because the power tunnel is far from the monitoring room, on-site power supply is unavailable, and data transmission from the site to the monitoring room via wired means is also impossible. Therefore, a power supply method combining CT induction power and solar panels is used to power the various distributed monitoring devices. The entire product is housed in a grounding box, which collects the grounding current from phases A, B, and C. The product operates in an intermittent mode. A typical timeframe for intermittent operation is a 1-hour charging cycle, followed by 15 seconds of power supply to the load. The product structure is as follows... Figure 1 As shown. Due to the possibility of sudden current changes on the grounding wire, the technical solution provided in this case is required for protection.

[0032] like Figure 2 As shown, according to an embodiment of the present invention, a distributed power supply low-current start-up pre-stage protection device includes: a high-current surge protection circuit connected to the output of the secondary coil of the CT magnetic ring, an EMC filter circuit connected to the output of the high-current surge protection circuit, a voltage regulator unit connected in parallel with the EMC filter circuit, and an energy release circuit connected to the output of the EMC filter circuit; the high-current surge protection circuit includes a varistor connected in series with a gas discharge tube.

[0033] According to one embodiment of the present invention, the voltage regulating unit is a Zener diode, such as D2 / D4 in the view.

[0034] According to one embodiment of the present invention, one end of the anti-high current surge circuit is connected to the L output terminal of the secondary coil of the CT magnetic ring, and the other end is connected to the N output terminal of the secondary coil of the CT magnetic ring. The two ends of the first varistor are connected to the L output terminal and the N output terminal. One end of the second varistor is connected to the L output terminal, and the second varistor is connected to the N output terminal through the third varistor, and the gas discharge tube is connected in series to ground.

[0035] According to one embodiment of the present invention, the switching circuit is a relay switching circuit.

[0036] According to one embodiment of the present invention, the anti-high current surge circuit further includes a bidirectional TVS diode whose two ends are connected to the output terminals of the secondary coil of the CT magnetic ring.

[0037] According to some embodiments of the present invention, the EMC filter circuit includes a first capacitor connected to the output terminal of the secondary coil of the CT magnetic ring and grounded through a fifth capacitor, a second capacitor connected to the output terminal of the secondary coil of the CT magnetic ring, a third capacitor and a fourth capacitor connected in series with the output terminal of the secondary coil of the CT magnetic ring, one end of the third capacitor being connected to the output terminal of the secondary coil of the CT magnetic ring, and the other end being grounded.

[0038] The energy release circuit includes a pre-amplifier and a MOSFET connected in series with the output of the EMC filter circuit. The MOSFET is grounded. The energy release circuit also includes electronic components for boosting the gate voltage of the MOSFET.

[0039] Preferably, the electronic component is a resistor.

[0040] According to some embodiments of the present invention, the series-connected preamplifier and MOSFET employ four branches, including a first preamplifier to a fourth preamplifier and a first MOSFET to a fourth MOSFET. The electronic component for boosting the gate voltage of the MOSFET is preferably a resistor. Once the MOSFET gate voltage reaches a certain specific value, the MOSFET begins to conduct, and excess energy current can be discharged through the first to fourth preamplifiers. The energy release circuit further includes a fifth resistor and a sixth resistor with a specific voltage value set. The specific voltage value is:

[0041] .

[0042] Any reference to "an embodiment," "embodiment," "illustrative embodiment," etc., means that the specific component, structure, or feature described in connection with that embodiment is included in at least one embodiment of the present invention. Such illustrative expressions throughout this specification do not necessarily refer to the same embodiment. Furthermore, when a specific component, structure, or feature is described in connection with any embodiment, it is claimed that implementing such a component, structure, or feature in connection with other embodiments falls within the scope of those skilled in the art.

[0043] Although specific embodiments of the invention have been described in detail with reference to several illustrative examples, it should be understood that those skilled in the art can devise various other modifications and embodiments that fall within the spirit and scope of the invention. Specifically, reasonable variations and modifications can be made to the arrangement of components and / or dependent combinations within the scope of the foregoing disclosure, drawings, and claims without departing from the spirit of the invention. The scope of these variations and modifications, apart from those concerning components and / or layout, is defined by the appended claims and their equivalents.

Claims

1. A pre-stage protection device for low-current startup of a distributed power source, characterized in that... ,include: A CT magnetic ring that collects electrical energy from the grounding wire to provide stable power to the corresponding equipment is connected to a high-current surge protection circuit that takes power from the secondary coil of the CT magnetic ring, an EMC filter circuit that outputs the high-current surge protection circuit, a voltage regulator unit that is connected in parallel with the EMC filter circuit, and an energy release circuit that outputs the EMC filter circuit. The circuit for preventing high current surges includes a varistor connected in series with a gas discharge tube. The circuit for preventing high current surges is connected at one end to the L output terminal of the secondary coil of the CT magnetic ring and at the other end to the N output terminal of the secondary coil of the CT magnetic ring. The first varistor is connected at both ends to the L output terminal and the N output terminal. The second varistor is connected at one end to the L output terminal and at the N output terminal through the third varistor, and is connected in series with the gas discharge tube to ground. The EMC filter circuit includes a first capacitor connected to the output terminal of the secondary coil of the CT magnetic ring and grounded through a fifth capacitor, a second capacitor connected to the output terminal of the secondary coil of the CT magnetic ring, and a third and a fourth capacitor connected in series with the output terminal of the secondary coil of the CT magnetic ring. One end of the third capacitor is connected to the output terminal of the secondary coil of the CT magnetic ring, and the other end is grounded.

2. The distributed power supply low-current start-up pre-stage protection device according to claim 1, characterized in that, The voltage stabilizing unit is a Zener diode.

3. The distributed power supply low-current start-up pre-stage protection device according to claim 1, characterized in that, The circuit for preventing high current surges also includes a bidirectional TVS diode whose two ends are connected to the output terminals of the secondary coil of the CT magnetic ring.

4. The distributed power supply low-current start-up pre-stage protection device according to claim 1, characterized in that, The energy release circuit includes a resistor and a MOSFET connected in series with the output of the EMC filter circuit. The MOSFET is grounded. The energy release circuit also includes electronic components for boosting the gate voltage of the MOSFET.

5. The distributed power supply low-current start-up pre-stage protection device according to claim 4, characterized in that, The electronic component is a resistor.

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