A single-phase circuit fault point tracking method and system

Abstract

This invention relates to the field of single-phase circuit fault location technology, specifically to a method and system for tracing single-phase circuit fault points. When measuring distributed capacitance, this application generates a rectangular oscillating wave, output to the capacitor under test, and uses an integrating circuit to measure the voltage value. The capacitance value is then confirmed based on the voltage value. Since distributed capacitance exists between conductors and its value is related to the conductor length, by measuring the distributed capacitance, the length of the conductor can be determined, i.e., the distance to the fault, thereby determining the fault location. This application can accurately locate fault points in wall-buried or underground circuits, reducing operating costs, and has the functions of accurately locating line fault points and testing the length of broken wires.

Description

Technical Field

[0001] This invention relates to the field of single-phase circuit fault location technology, specifically to a method and system for tracing fault points in single-phase circuits. Background Technology

[0002] Household power supplies are typically classified as three-phase four-wire systems based on their current-carrying conductors before entering the user's home. This consists of three phase wires (electrical symbols: A, B, C, cable colors: yellow, green, red), one neutral wire (electrical symbol: N, cable color: blue), and a grounding wire (cable color: yellow-green). A single-phase system consists of any one of the three phase wires and one neutral wire. It is commonly referred to as the "live wire" or "neutral wire" and usually refers to 220V, 50Hz AC power. In electrical engineering, single-phase voltage is also called "phase voltage." Most household appliances use single-phase AC power, meaning they are compatible with 220V, 50Hz AC power consisting of one phase wire and one neutral wire. Therefore, single-phase circuits are widely used in various public places, offices, office buildings, shopping malls, and residential homes.

[0003] To achieve aesthetically pleasing wiring or due to plumbing and electrical renovations, most single-phase power lines are buried in walls or run through underground cables, making it difficult to observe damage to the wires. When a wire breaks, if it is not dealt with promptly, it can cause electric shocks and electrical fires, posing a significant threat to personal and property safety and contributing to numerous fires caused by household appliances.

[0004] Therefore, in single-phase circuit operation, it is difficult to pinpoint the fault location when the wiring is buried in walls or underground. Thus, there is an urgent need for a simple device to locate circuit faults. Summary of the Invention

[0005] In order to calculate the distance between the detection point and the fault point and thus locate the fault point, this invention provides a single-phase circuit fault point tracking method, comprising:

[0006] S101. The high-frequency pulse circuit applies voltage Vi to the single-phase circuit and sends square wave pulses to the single-phase circuit.

[0007] S102. When the square wave pulse decreases, obtain the voltage Vo at the fault point;

[0008] S103. Calculate the distributed capacitance C based on voltage Vi and voltage Vo;

[0009] S104. Calculate the cable length L based on the distributed capacitance C, and determine the distance to the fault point based on the cable length L.

[0010] Preferably, step S101 further includes:

[0011] Sending signals of continuously increasing frequency to a single-phase circuit;

[0012] When a single-phase circuit resonates, the resonant frequency that triggers the single-phase circuit is calculated.

[0013] The control square wave pulse frequency value is lower than the resonant frequency value.

[0014] Preferably, step S102 further includes:

[0015] A high-frequency pulse circuit generates a rectangular oscillating wave, which is output to the single-phase circuit under test.

[0016] Observe the frequency of parasitic oscillations along the rising edge of the rectangular oscillating wave;

[0017] When the rectangular oscillating wave is input to the location of the fault, the square wave pulse decreases.

[0018] Preferably, step S103 further includes the formula for calculating distributed capacitance:

[0019] Vo = -1 / R1C∫Vidt;

[0020] C = -1 / R1Vo∫Vidt;

[0021] R1 is the resistance value of R1.

[0022] Preferably, step S104 further includes: the formula for calculating cable length L.

[0023] C = ε*S / d;

[0024] ε is the dielectric constant;

[0025] S represents the area;

[0026] d is the distance between the line and the ground;

[0027] Where S = D * L;

[0028] D is the diameter of the cable core wire;

[0029] L is the cable length;

[0030] Therefore, C = ε * D * L / d;

[0031] L=C*d / ε*D.

[0032] The present invention also provides a single-phase circuit fault point tracking system, comprising: a microcontroller;

[0033] The microcontroller is connected to a high-frequency pulse circuit;

[0034] The microcontroller applies voltage Vi to the single-phase circuit through a high-frequency pulse circuit and sends square wave pulses to the single-phase circuit.

[0035] When the microcontroller detects a drop in the square wave pulse, it acquires the voltage Vo at the fault point.

[0036] The microcontroller calculates the distributed capacitance C based on the pulse voltage Vi and the output voltage Vo, and then calculates the cable length L using the distributed capacitance C.

[0037] Preferably, it also includes a resonant frequency testing circuit;

[0038] The microcontroller is connected to the resonant frequency test circuit, and sends a signal with a continuously increasing frequency to the single-phase circuit through the resonant frequency test circuit.

[0039] When the microcontroller detects resonance, it calculates the resonant frequency of the single-phase circuit.

[0040] Preferably, it also includes an integrating circuit;

[0041] Integrating circuits include operational amplifiers;

[0042] The inverting input of the operational amplifier is connected to one end of resistor R1, and a voltage Vi is applied to the other end of resistor R1.

[0043] The inverting input of the operational amplifier is also connected to one end of the distributed capacitance C;

[0044] The other end of the distributed capacitor C is connected to the output terminal of the operational amplifier;

[0045] The non-inverting input of the operational amplifier is connected to one end of resistor R2, and the other end of resistor R2 is grounded.

[0046] Preferably, it further includes a first terminal and a second terminal;

[0047] Both the first and second terminals are connected to the high-frequency pulse circuit.

[0048] The first terminal is connected to the live wire of a single-phase circuit;

[0049] The second terminal is connected to the neutral wire of the single-phase circuit.

[0050] Preferably, it also includes a DC power supply;

[0051] The DC power supply is connected to the microcontroller to power the system;

[0052] The microcontroller is also connected to a display screen, which shows the voltage Vi, voltage Vo, and cable length L.

[0053] Both the first and second terminals use picket clamps.

[0054] As can be seen from the above technical solutions, the present invention has the following advantages:

[0055] This invention uses a first terminal and a second terminal to clamp the live wire and neutral wire of a single-phase circuit, respectively, to determine the detection point. Through the first and second terminals, a resonant frequency testing circuit measures the resonant point of the single-phase circuit. Based on this resonant point, the frequency that triggers resonance in the single-phase circuit is obtained. When a high-frequency pulse circuit sends a square wave pulse to the single-phase circuit, ensuring the pulse frequency is below this value, resonance is avoided, thus ensuring the stability and reliability of the fault point measurement process. This invention detects the input voltage Vi and the output voltage Vo at the fault point, calculates the distributed capacitance C using an integrator circuit, and determines the distance from the detection point to the fault point based on the proportional relationship between capacitance and wire length, thereby pinpointing the location of the fault. Attached Figure Description

[0056] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a schematic diagram of a single-phase circuit fault point tracing method.

[0058] Figure 2 This is a schematic diagram of a single-phase circuit fault tracing system.

[0059] Figure 3 This is a schematic diagram of a single-phase circuit fault point tracing system.

[0060] Figure 4 This is an integrator circuit diagram.

[0061] In the diagram: 1-DC power supply, 2-resonant frequency test circuit, 3-integrating circuit, 4-microcontroller, 5-high frequency pulse circuit, 6-display screen, 7-first terminal, 8-second terminal. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] Unless otherwise defined, all technical and scientific terms used in the embodiments of this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in the embodiments of this invention is for descriptive purposes only and is not intended to limit the invention.

[0064] The units and algorithm steps of the various examples described in the embodiments of the single-phase circuit fault point tracing system provided by this invention can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0065] The block diagrams shown in the accompanying drawings of the single-phase circuit fault tracing system provided by this invention are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0066] Before providing a further detailed description of the embodiments of the present invention, the nouns and terms involved in the embodiments of the present invention will be explained, and the nouns and terms involved in the embodiments of the present invention shall be interpreted as follows.

[0067] Parasitic oscillations: Oscillations that are inconsistent with the correct operating frequency are called parasitic oscillations, that is, oscillations that are independent of the operating frequency or outside the operating frequency range and originate from parasitic parameters.

[0068] This invention uses the resonance method to measure and obtain the distributed capacitance and resonant frequency: using this ring inductor and amplifier circuit to form a resonant circuit, when the circuit is in resonance, wL=1 / wC.

[0069] Between conductors, and between conductors and the ground, and even in air (which is an insulator), there is a potential difference, forming capacitance and capacitance between them. These capacitances have capacitive reactance and impedance, varying with distance and voltage levels. Because there is no fixed pattern, they are distributed throughout the conductors, hence the terms distributed capacitance and distributed resistance. Distributed capacitance exists between two conductors with a voltage difference that are insulated from each other. Therefore, in any circuit, distributed capacitance will form between any two insulated conductors with a voltage difference; the only difference is the magnitude of the distributed capacitance. The magnitude of distributed capacitance depends on the cable's geometry, length, and insulation material, and it is composed of two conductors with a voltage difference that are insulated from each other.

[0070] Integrating circuit 3 is an important unit commonly used in control and measurement systems. Its charging and discharging process can be used to realize delay, timing and the generation of various waveforms. It is a widely used analog signal processing circuit.

[0071] High-frequency pulse voltage refers to a brief change in voltage or current. Common pulse shapes include rectangular pulses, square wave pulses, sharp pulses, sawtooth pulses, stepped pulses, intermittent sine pulses, etc. Pulse voltage is characterized by abrupt changes and discontinuities.

[0072] This invention provides a single-phase circuit fault point tracing system, such as... Figure 2-4 As shown, it includes: a microcontroller 4, which is an 8-bit microcontroller, specifically an AVR series or PIC series microcontroller. The microcontroller 4 is connected to a high-frequency pulse circuit 5, and also has a first terminal 7 and a second terminal 8. Both the first terminal 7 and the second terminal 8 are connected to the high-frequency pulse circuit 5 and the resonant frequency test circuit 2. Both the first terminal 7 and the second terminal 8 use crane clips. The first terminal 7 has a red crane clip, and the second terminal 8 has a blue crane clip. The first terminal 7 is connected to the live wire of the single-phase circuit, and the second terminal 8 is connected to the neutral wire of the single-phase circuit.

[0073] The microcontroller 4 is connected to the resonant frequency testing circuit 2. The resonant frequency testing circuit 2 sends a signal with an increasingly higher frequency to the single-phase circuit. When the microcontroller 4 detects resonance, it calculates the resonant frequency value of the single-phase circuit. The microcontroller 4 applies a voltage Vi to the single-phase circuit through the high-frequency pulse circuit 5 and sends a square wave pulse to the circuit. The microcontroller 4 controls the frequency of the square wave pulse to be lower than the resonant frequency value. When a drop in the square wave pulse is detected, the microcontroller 4 obtains the voltage Vo at the fault point. Based on the pulse voltage Vi and the output voltage Vo, the microcontroller 4 calculates the distributed capacitance C and then calculates the cable length L using the distributed capacitance C. The microcontroller 4 is also connected to a display screen 6, which displays the voltage Vi, voltage Vo, and cable length L. The microcontroller 4 is also connected to a DC power supply 1, which uses a rechargeable lithium battery to power the system.

[0074] The present invention also includes an integrating circuit 3, which includes an operational amplifier. The inverting input terminal of the operational amplifier is connected to one end of a resistor R1, and a voltage Vi is applied to the other end of the resistor R1. The inverting input terminal of the operational amplifier is also connected to one end of a distributed capacitor C, and the other end of the distributed capacitor C is connected to the output terminal of the operational amplifier. The non-inverting input terminal of the operational amplifier is connected to one end of a resistor R2, and the other end of the resistor R2 is grounded.

[0075] This invention further illustrates a single-phase circuit fault point tracking system and detection process through a specific embodiment. A DC power supply 1 powers the device. A microcontroller 4 is connected to a resonant frequency test switch, an integrating circuit 3, a high-frequency pulse circuit 5, and a display screen 6. The circuit is constructed using the microcontroller 4 to control the device's operation. A red hook-and-eye clip is connected to the live wire, and a blue hook-and-eye clip is connected to the neutral wire. When the resonant frequency test circuit 2 switch is clicked, the microcontroller 4 sends a series of signals with continuously increasing frequencies until the circuit resonates, and the resonant frequency is calculated. The microcontroller 4 controls the high-frequency pulse circuit 5 to emit high-frequency pulses at a fixed frequency lower than the resonant frequency to measure the distributed capacitance. The frequency of parasitic oscillations on the rising edge is observed. When the square wave pulse falls, the microcontroller 4 controls the integrating circuit 3 to calculate the length of the faulty circuit or cable, and displays the faulty circuit length on the display screen 6.

[0076] Based on the above system, the present invention also provides a method for tracing fault points in a single-phase circuit, such as... Figure 1 As shown, step S101 includes: the microcontroller 4 sends a signal with a continuously increasing frequency to the single-phase circuit through the resonant frequency test circuit 2; when the single-phase circuit resonates, the resonant frequency value that triggers the single-phase circuit is calculated. The high-frequency pulse circuit 5 applies a voltage Vi to the single-phase circuit and sends a square wave pulse to the single-phase circuit, controlling the square wave pulse frequency value to be lower than the resonant frequency value.

[0077] Step S102 includes: the high-frequency pulse circuit 5 generates a rectangular oscillation wave, outputs it to the single-phase circuit under test, observes the frequency of parasitic oscillation at the rising edge of the rectangular oscillation wave, when the rectangular oscillation wave is input to the location of the fault point, the square wave pulse drops, and when the square wave pulse drops, the voltage Vo at the fault point is obtained.

[0078] Step S103 includes: calculating the distributed capacitance C based on voltage Vi and voltage Vo. Since the integrator circuit 3: Vo=-1 / R1C∫Vidt, C=-1 / R1Vo∫Vidt, where R1 is the resistance value of R1.

[0079] S104. The cable length L is calculated based on the distributed capacitance C. The formula for calculating the cable length L is: C=ε*S / d; ε is the dielectric constant; S is the area; d is the distance between the line and the ground; where S=D*L; D is the diameter of the cable core; L is the cable length; therefore, C=ε*D*L / d; L=C*d / ε*D, and the cable length L is the distance from the detection point to the fault point, which is then determined.

[0080] This invention further illustrates the single-phase circuit fault point tracing method of the present invention through specific embodiment two. Since the circuit under test is not a purely resistive circuit, the test contacts are connected to the circuit, and the resonant frequency test circuit 2 is activated to induce resonance in the circuit, thus locating the resonant point of the circuit under test. A high-frequency pulse is activated, and the pulse frequency is controlled to be lower than the resonant point of the circuit under test. The frequency of parasitic oscillations is observed; if the voltage drops, the location of the fault point can be deduced. Specifically, the distributed capacitance is measured by generating a rectangular oscillation wave and outputting it to the capacitor under test. The voltage value is measured using an integrating circuit 3, and the distributed capacitance value is confirmed based on the voltage value. The distributed capacitance value is directly proportional to the wire length, and the final output wire length value is confirmed; this value is the distance from the test point to the break point.

[0081] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for tracing fault points in a single-phase circuit, characterized in that, include: S101. The high-frequency pulse circuit applies voltage Vi to the single-phase circuit and sends square wave pulses to the single-phase circuit. S102. When the square wave pulse decreases, obtain the voltage Vo at the fault point; S103. Calculate the distributed capacitance C based on voltage Vi and voltage Vo; S104. Calculate the cable length L based on the distributed capacitance C, and determine the distance to the fault point based on the cable length L. Step S102 also includes: A high-frequency pulse circuit generates a rectangular oscillating wave, which is output to the single-phase circuit under test. Observe the frequency of parasitic oscillations along the rising edge of the rectangular oscillating wave; When a rectangular oscillating wave is input to the location of the fault, the square wave pulse decreases. Step S103 also includes the formula for calculating distributed capacitance: ； R1 is the resistance value of resistor R1; It also includes integrating circuits; Integrating circuits include operational amplifiers; The inverting input of the operational amplifier is connected to one end of resistor R1, and a voltage Vi is applied to the other end of resistor R1. The inverting input of the operational amplifier is also connected to one end of the distributed capacitance C; The other end of the distributed capacitor C is connected to the output terminal of the operational amplifier; The non-inverting input of the operational amplifier is connected to one end of resistor R2, and the other end of resistor R2 is grounded.

2. The single-phase circuit fault point tracing method according to claim 1, characterized in that, Step S101 also includes: Sending signals of continuously increasing frequency to a single-phase circuit; When a single-phase circuit resonates, the resonant frequency that triggers the single-phase circuit is calculated. The control square wave pulse frequency value is lower than the resonant frequency value.

3. The single-phase circuit fault point tracing method according to claim 1, characterized in that, Step S104 also includes: the formula for calculating cable length L. ； ε is the dielectric constant; S represents the area; d is the distance between the line and the ground; in, ; D is the diameter of the cable core wire; L is the cable length; Therefore ; 。 4. A single-phase circuit fault point tracing system, characterized in that, The system employs the single-phase circuit fault point tracing method as described in any one of claims 1 to 3, comprising: a microcontroller; The microcontroller is connected to a high-frequency pulse circuit; The microcontroller applies voltage Vi to the single-phase circuit through a high-frequency pulse circuit and sends square wave pulses to the single-phase circuit. When the microcontroller detects a drop in the square wave pulse, it acquires the voltage Vo at the fault point. The microcontroller calculates the distributed capacitance C based on the pulse voltage Vi and the output voltage Vo, and then calculates the cable length L using the distributed capacitance C. It also includes integrating circuits; Integrating circuits include operational amplifiers; The inverting input of the operational amplifier is connected to one end of resistor R1, and a voltage Vi is applied to the other end of resistor R1. The inverting input of the operational amplifier is also connected to one end of the distributed capacitance C; The other end of the distributed capacitor C is connected to the output terminal of the operational amplifier; The non-inverting input of the operational amplifier is connected to one end of resistor R2, and the other end of resistor R2 is grounded.

5. The single-phase circuit fault point tracing system according to claim 4, characterized in that, It also includes a resonant frequency testing circuit; The microcontroller is connected to the resonant frequency test circuit, and sends a signal with a continuously increasing frequency to the single-phase circuit through the resonant frequency test circuit. When the microcontroller detects resonance, it calculates the resonant frequency of the single-phase circuit.

6. The single-phase circuit fault point tracing system according to claim 4, characterized in that, It also includes a first terminal and a second terminal; Both the first and second terminals are connected to the high-frequency pulse circuit. The first terminal is connected to the live wire of a single-phase circuit; The second terminal is connected to the neutral wire of the single-phase circuit.

7. The single-phase circuit fault point tracing system according to claim 6, characterized in that, It also includes a DC power supply; The DC power supply is connected to the microcontroller to power the system; The microcontroller is also connected to a display screen, which shows the voltage Vi, voltage Vo, and cable length L. Both the first and second terminals use picket clamps.

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