CN108051695B - AC/DC ground fault analyzer and ground fault finding and positioning system - Google Patents
AC/DC ground fault analyzer and ground fault finding and positioning system Download PDFInfo
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- CN108051695B CN108051695B CN201810048687.4A CN201810048687A CN108051695B CN 108051695 B CN108051695 B CN 108051695B CN 201810048687 A CN201810048687 A CN 201810048687A CN 108051695 B CN108051695 B CN 108051695B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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Abstract
The invention discloses an AC/DC ground fault analyzer and a ground fault locating system, the AC/DC ground fault analyzer comprises: the current detection circuit is used for controlling the change of current so as to detect the change of the voltage to the ground of the current tested system; the voltage sampling circuit is connected to the current detection circuit and is used for collecting the grounding voltage of the current tested system and carrying out data processing on the grounding voltage; the grounding resistance calculation module is connected to the current detection circuit and is used for calling a corresponding detection algorithm according to the voltage type of the current tested system to calculate the grounding resistance; the voltage deviation amplitude acquisition circuit is used for acquiring the voltage amplitude of the AC/DC ground fault analyzer and the amplitude of the current measured system to-ground voltage deviation; the singlechip is used for controlling the circuit and analyzing and calculating the grounding faults. The embodiment realizes the detection of the AC/DC system ground fault, improves the compatibility and the accuracy of AC/DC ground fault detection, and more comprehensively meets the requirements of users.
Description
Technical Field
The embodiment of the invention relates to a ground fault locating technology, in particular to an alternating current-direct current ground fault analyzer and a ground fault locating system.
Background
The ground fault locator is widely applied to various fields of electric power, telecommunication, metallurgy, petrochemical industry, textile industry and the like and plays an important role. If the system ground fault cannot be solved in time, huge potential safety hazards can be brought to the generation.
The grounding fault locating instrument in the current market is commonly a direct current system grounding fault locating instrument, and mainly aims at locating the grounding fault in the direct current system. However, the ac system also has a hidden trouble of ground fault, but no instrument for searching the ac system ground fault is available, which cannot meet the needs of the current user, and the ground fault searching instrument for ac and dc is a blank in the market.
Disclosure of Invention
The invention provides an AC/DC ground fault analyzer and a ground fault locating system, which are used for detecting, analyzing and locating the ground fault of an AC/DC system.
In a first aspect, an embodiment of the present invention provides an ac/dc ground fault analyzer, including:
the current detection circuit is used for controlling the change of current so as to detect the change of the voltage to the ground of the current tested system;
the voltage sampling circuit is connected to the current detection circuit and is used for identifying the voltage type of the current tested system, collecting the grounding voltage of the current tested system and carrying out data processing on the grounding voltage of the current tested system;
the grounding resistance calculation module is connected to the voltage sampling circuit and is used for calling corresponding detection algorithms according to different voltage types and voltage grades of the current tested system to calculate the grounding resistance of the current tested system;
the voltage deviation amplitude acquisition circuit is connected to the current detection circuit and is used for acquiring the voltage amplitude of the AC/DC ground fault analyzer and the current measured system ground voltage deviation amplitude;
the single chip microcomputer is connected to the current detection circuit, the voltage sampling circuit, the grounding resistance calculation module and the voltage deviation amplitude acquisition circuit, and is used for controlling the current detection circuit, the voltage sampling circuit, the grounding resistance calculation module and the voltage deviation amplitude acquisition circuit and analyzing and calculating the grounding fault of the current tested system.
In a second aspect, an embodiment of the present invention further provides a ground fault locating system, including a detector and the ac/dc ground fault analyzer described above.
The invention provides the AC/DC ground fault analyzer and the ground fault locating system, which can be compatible with the ground fault detection of the DC system and the AC system, fill the blank of the ground fault locating instrument of the current AC system, and more comprehensively meet the requirements of users on the ground fault detection.
Drawings
Fig. 1 is a schematic structural diagram of an ac/dc ground fault analyzer according to a first embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a current detection circuit in an ac/dc ground fault analyzer according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of a voltage sampling circuit in an ac/dc ground fault analyzer according to a first embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a voltage deviation amplitude acquisition circuit in an ac/dc ground fault analyzer according to a first embodiment of the present invention;
fig. 5 is a schematic structural diagram of a ground fault locating system according to a second embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Example 1
Fig. 1 is a schematic structural diagram of an ac/dc ground fault analyzer according to a first embodiment of the present invention, as shown in fig. 1, the ac/dc ground fault analyzer includes:
a current detection circuit 110 for controlling the change of the current to detect the change of the ground voltage of the current system under test;
the voltage sampling circuit 120 is connected to the current detection circuit 110, and is used for identifying the voltage type of the current system to be tested, collecting the ground voltage of the current system to be tested, and performing data processing on the ground voltage of the current system to be tested;
the grounding resistance calculation module 130 is connected to the voltage sampling circuit 120 and is used for calling corresponding detection algorithms according to different voltage types and voltage grades of the current tested system to calculate the grounding resistance of the current tested system;
the voltage deviation amplitude acquisition circuit 140 is connected to the current detection circuit 110 and is used for acquiring the voltage amplitude of the AC/DC ground fault analyzer and the amplitude of the current measured system ground voltage deviation;
the single chip microcomputer 150 is connected to the current detection circuit 110, the voltage sampling circuit 120, the ground resistance calculation module 130 and the voltage deviation amplitude acquisition circuit 140, and is used for controlling the current detection circuit 110, the voltage sampling circuit 120, the ground resistance calculation module 130 and the voltage deviation amplitude acquisition circuit 140 and analyzing and calculating the ground fault of the current tested system.
Fig. 2 is a schematic circuit diagram of a current detection circuit in an ac/dc ground fault analyzer according to an embodiment of the present invention, as shown in fig. 2, the current detection circuit includes: operational amplifier IC7 model OPA454, triode T1 model 2N3439, resistor R19, resistor R23, resistor R25, resistor R26, resistor R27, resistor R28, resistor R29, resistor R30, resistor R31, resistor R32, resistor R36, resistor R37, resistor R39, capacitor C35, capacitor C36, capacitor C37, capacitor C38, optocoupler relays U1, U2 and U3 model AQV 259.
Wherein the pin 3 of the operational amplifier IC7 is connected to the singlechip, the pin 1 of the operational amplifier IC7 is grounded, the pin 6 of the operational amplifier IC7 is connected to the base of the triode T1, the emitter of the triode T1 is connected to the first end of the resistor R30, the first end of the resistor R23, the first end of the resistor R25, the first end of the resistor R26, the first end of the resistor R28 and the first end of the resistor R29, the second end of the resistor R30 is connected to the pin 2 of the operational amplifier IC7, the first end of the resistor R36, the first end of the capacitor C35 and the first end of the capacitor C36, the second end of the resistor R36 is connected to the first end of the resistor R39, the second end of the capacitor C35 and the second end of the capacitor C36 are grounded, the second end of the resistor R23, the second end of the resistor R25, the second end of the resistor R26, the second end of the resistor R28 and the second end of the resistor R29 are connected to the first end of the resistor R31, the pins 4 of the optocoupler relays U1, U2 and U3, the pins 1 of the optocoupler relays U1, U2 and U3 are respectively connected to the first end of the resistor R19, the first end of the resistor R27 and the first end of the resistor R32, the second end of the resistor R19, the second end of the resistor R27 and the second end of the resistor R32 are respectively connected to the singlechip, the pins 2 of the optocoupler relays U1, U2 and U3 are respectively connected to the pins APHASE, BPHASE and CPE, the pins APHASE, BPHASE and CPHASE are respectively connected to the three voltage detection inlets of the AC-to-DC fault analyzer, the second end of the optocoupler relays U1, U2 and U3 are respectively connected to the second end of the resistor R37, the first end of the capacitor C37 and the first end of the capacitor C38, and the second end of the resistor R37, the second end of the capacitor C37 and the second end of the capacitor C38 are grounded.
The voltage Uout output by the pin PA4 of the singlechip is transmitted to the pin 3 of the operational amplifier IC7 with the model of OPA454, wherein the voltage Uout is 0-2.5V. A triode of model 2N3439 is connected to the output pin 6 of the operational amplifier IC7, the emitter of which is connected to the first terminal of the resistor R30, and the second terminal of the resistor R30 is connected to the pin 2 of the operational amplifier IC7, thus forming a feedback network forming an amplifying circuit controlled by the pin 3 of the operational amplifier IC 7.
The working principle of the circuit diagram is as follows: the pin PA4 of the singlechip controls and outputs 0-2.5V of adjustable voltage to the pin 3 of the operational amplifier IC7, the adjustable voltage is outputted to the base electrode of the triode T1 through the pin 6 of the operational amplifier IC7 after passing through a feedback network formed by the operational amplifier IC7, the amplification factor of the triode T1 is controlled, the emitter electrode of the triode T1 outputs 0-50V of voltage value, the current value obtained after the voltage value is outputted through a resistor formed by parallel connection of a resistor R23, a resistor R25, a resistor R26, a resistor R28 and a resistor R29 is outputted to the optocoupler relays U1, U2 and U3, and the optocoupler relays U1, U2 and U3 serve as switches. The control pins of the optocoupler relays U1, U2 and U3 with the model number AQY259 are pin 1 and pin 2, the pin 2 of the optocoupler relay U1 is grounded, when the pin 1 is at a high level, the pin 4 and the pin 6 of the optocoupler relay U1 are conducted, when the pin 1 is at a low level, the pin 4 and the pin 6 of the optocoupler relay U1 are disconnected, the working principles of the optocoupler relays U2 and U3 are the same as those of the optocoupler relay U1, and APHASE, BPHASE and CPHASE corresponding to the pins 6 of the optocoupler relays U1, U2 and U3 are respectively connected to three voltage detection inlets on the AC/DC ground fault analyzer. It should be noted that, the control pins 1 of the optocoupler relays U1, U2 and U3 are respectively connected to the pins PA5, PA6 and PA7 of the single-chip microcomputer, and the single-chip microcomputer controls the pins 4 of the optocoupler relays to be connected to the three detection access ports on the ac/dc ground fault analyzer respectively corresponding to the pins APHASE, BPHASE and CPHASE respectively corresponding to the pins 6 of the optocoupler relays U1, U2 and U3 by controlling the high and low levels of the control pins 1 of the optocoupler relays U1, U2 and U3, and when the pin 4 of the optocoupler relay is connected to the three voltage detection access ports on the ac/dc ground fault analyzer, the current measured system will change in voltage value to ground.
Fig. 3 is a schematic circuit diagram of a voltage sampling circuit in an ac/dc ground fault analyzer according to an embodiment of the present invention, as shown in fig. 3, the voltage sampling circuit includes: resistor R6, resistor R7, resistor R8, resistor R9, resistor R11, resistor R70, resistor R71, capacitor C18, capacitor C19, capacitor C20, resistor C23, diode D5, diode D6, diode D7, and operational amplifier IC2 of model OP-07.
The first end of the resistor R8 is connected to the pin 3 of the operational amplifier IC2 and the first end of the capacitor C23, the second end of the resistor R8 is connected to the first end of the resistor R7 and the first end of the capacitor C18, the second end of the capacitor C18 is connected to the pin 2 of the operational amplifier IC2, the pin 6 and the first end of the resistor R9, the second end of the resistor R9 is connected to the positive electrode of the diode D5, the negative electrode of the diode D6 and the singlechip, the negative electrode of the diode D5 is connected to +3.3v power supply, the positive electrode of the diode D6 is grounded, the second end of the capacitor C23 is grounded, the pin 7 of the operational amplifier IC2 is connected to +5v power supply, the pin 4 of the operational amplifier IC2 is connected to-5V power supply, the second end of the resistor R7 is connected to the first end of the resistor R11, the first end of the capacitor C19, the negative electrode of the capacitor C20 and the second end of the capacitor C6 are connected to the second end of the resistor C7, the second end of the resistor C7 is connected to the resistor C70, and the second end of the resistor C7 is connected to the resistor C70.
The PC5 is an acquisition pin of the singlechip, and the BPHASE end is connected to one voltage detection access port of the AC/DC ground fault analyzer. The voltage sampling circuits connected to the other two voltage detection access ports of the ac/dc ground fault analyzer are the same as those described above, and will not be described here.
The voltage sampling circuit identifies the voltage type and the voltage class of the current tested system and collects the voltage to the ground of the current tested system, wherein the voltage type is direct current voltage or alternating current voltage, and the voltage class is 220V, 380V, 450V, 750V and 1000V. The voltage that voltage detection access mouth gathered carries out the rectification through rectifier diode, with alternating voltage conversion direct current voltage, solves alternating voltage and direct current voltage's difference in gathering, does not need to adopt two different circuits to gather alternating voltage and direct current voltage respectively. As shown in fig. 3, the voltage connected to the BPHASE end is rectified by a diode D7 to obtain a direct-current voltage, and then divided by a resistor R6 and a resistor R11, and the voltage passes through a second-order low-pass filter circuit formed by an operational amplifier IC2, a resistor R7, a resistor R8, a capacitor C18 and a capacitor C23 with the model OP-07, reaches a voltage acquisition port through a resistor R9, and then is converted from an analog signal to a digital signal through an analog-digital converter in the singlechip. The diode D5 and the diode D6 play a role in clamping protection, and the overlarge voltage in the voltage sampling process is prevented from burning out the acquisition pin of the singlechip.
And the grounding resistance calculation module is connected to the voltage sampling circuit and is used for calling a corresponding detection algorithm according to different voltage types and voltage grades of the current tested system to calculate the grounding resistance of the current tested system. The grounding resistance calculation module is used for executing calculation of the grounding resistance in the singlechip. The singlechip controls the high and low levels of the control pins 1 of the optocoupler relays U1, U2 and U3 to control the pins 4 of the optocoupler relays to be respectively connected to the APHASE, BPHASE and CPHASE corresponding to the pins 6 of the optocoupler relays U1, U2 and U3 respectively and connected to the three voltage detection access ports on the AC/DC ground fault analyzer. The three optocoupler relays U1, U2 and U3 are opened one by one, when the pin 4 of the optocoupler relay is connected to three detection access ports on the AC/DC ground fault analyzer, the voltage value of the optocoupler relay to the ground can be changed, and the singlechip can calculate the resistance value of the three detection access ports to the ground through a corresponding algorithm by collecting the voltage value before the change and the voltage value after the change, and determine whether the current detection system has faults according to the resistance value.
It should be noted that, in order to achieve good compatibility between the ac system and the dc system for ground fault detection, the ac system and the dc system adopt the same principle of detection method. The detection method provided by the embodiment is a combination of a balanced bridge method and an unbalanced bridge method. After the AC/DC ground fault analyzer identifies the type of the connected voltage, the voltage is sampled, and then different detection algorithms are adopted for different identified voltage systems, wherein the voltage types are divided into DC voltage and AC voltage. The method comprises the steps of setting and starting an unbalanced bridge according to set parameters through the detection algorithm, detecting the change of the current measured system to the ground voltage, and then calculating the ground resistance of the current measured system according to corresponding algorithms corresponding to different types of the current measured system.
Fig. 4 is a schematic circuit diagram of a voltage deviation amplitude acquisition circuit in an ac/dc ground fault analyzer according to an embodiment of the present invention, as shown in fig. 4, the voltage deviation amplitude acquisition circuit includes: resistor R20, resistor R21, resistor R22, resistor R24, capacitor C32, capacitor C33, diode D12, diode D13, and operational amplifier IC6 of model OP-07.
The pin 3 of the operational amplifier IC6 is connected to the first end of the resistor R21 and the first end of the capacitor C33, the second end of the capacitor C33 is grounded, the second end of the resistor R21 is connected to the first end of the resistor R20 and the first end of the capacitor C32, the pin 2 of the operational amplifier IC6 is connected to the second end of the capacitor C32, the first end of the resistor R22 and the pin 6 of the operational amplifier IC6, the second end of the resistor R22 is connected to the positive electrode of the diode D12, the negative electrode of the diode D13 and the first end of the resistor R24, the negative electrode of the diode D12 is connected to the +3.3v power supply, the positive electrode of the diode D13 is grounded, the pin 7 of the operational amplifier IC6 is connected to the +5v power supply, and the pin 4 of the operational amplifier IC6 is connected to the-5V power supply.
Wherein, voltage deviation amplitude acquisition circuit includes: the circuit structures of the voltage amplitude acquisition circuit of the AC/DC ground fault analyzer and the ground voltage deviation amplitude acquisition circuit of the current tested system are the same, and are shown in figure 4. In combination with the circuit diagrams of fig. 2 and fig. 4, in the detection process, the voltage of the ac/dc ground fault analyzer is divided by the resistors R36 and R39, the divided voltage is input into the voltage amplitude acquisition circuit of the ac/dc ground fault analyzer, the voltage is processed by the numerical algorithm and is displayed on the display screen of the ac/dc ground fault analyzer after passing through the second-order low-pass filter consisting of the operational amplifier IC6 with the model OP-07, the resistor R20, the resistor R21, the capacitor C32 and the capacitor C33, and then is divided by the resistor R22 and the resistor R24 with the reference voltage, so as to obtain the final voltage value, and the final voltage value is directly returned to the analog/digital converter of the single chip microcomputer. In the same way, in the detection process, the same principle is adopted for collecting the voltage deviation amplitude value of the current measured system to the ground, the voltage after the voltage division is input into the current measured system to the ground voltage deviation amplitude value collecting circuit through the resistor R31 and the resistor R37, and the obtained voltage deviation amplitude value of the current measured system is displayed on the display screen of the AC/DC ground fault analyzer after the same processing.
In the existing ground fault finding device, no device is provided for the detecting device itself in the process of detecting faults because of the voltage fluctuation amplitude generated by bridge cutting and the voltage required by the device itself in the process of starting the detecting, so that many users cannot evaluate whether the ground fault finding device has potential threat to the detected system in the process of detecting the faults of the current detected system. Therefore, in the embodiment, the voltage required by the detection of the AC/DC ground fault analyzer and the voltage deviation amplitude value of the current tested system to the ground in the detection process are displayed in real time, and a user evaluates whether the AC/DC ground fault analyzer has potential threat to the current tested system or not through the displayed voltage deviation amplitude value; in addition, the magnitude of the deviation amplitude of the current tested system to the ground voltage in the detection process can be checked, and the corresponding adjustment can be carried out by combining the fault property of the current tested system, so that the method is applicable to all fault types of the tested system, the working efficiency is improved in the fault detection process, and the safe operation of the system is better ensured.
The embodiment provides an AC/DC ground fault analyzer which controls the change of current through a current detection circuit to detect the change of the voltage to the ground of a current system to be detected; the voltage sampling circuit is connected to the current detection circuit, recognizes the voltage type and the voltage class of the current tested system, collects the grounding voltage of the current tested system, and performs data processing on the grounding voltage of the current tested system; the grounding resistance calculation module is connected to the voltage sampling circuit, and calls a corresponding detection algorithm to calculate the grounding resistance of the current tested system according to different voltage types and voltage grades of the current tested system; the voltage deviation amplitude acquisition circuit is connected to the current detection circuit and is used for acquiring the voltage amplitude of the AC/DC ground fault locating device and the amplitude of the voltage deviation of the tested system to the ground; the single chip microcomputer is connected to the voltage sampling circuit, the current detection circuit, the grounding resistance calculation module and the voltage deviation amplitude acquisition circuit and is used for analyzing and calculating grounding faults, so that the detection of the grounding faults of the alternating current system and the direct current system is realized, the compatibility and the accuracy of the detection of the alternating current-direct current grounding faults are improved, and the requirements of users are more comprehensively met.
Example two
Fig. 5 is a schematic structural diagram of a ground fault locating system according to a second embodiment of the present invention, as shown in fig. 5, where the ground fault locating system includes a detector and the ac/dc ground fault analyzer.
The ground fault locating system also comprises an indicator lamp (not shown in the figure), a display screen and a voice broadcasting module (not shown in the figure), wherein the indicator lamp is used for indicating the fault condition of the current tested system; the display screen is used for displaying the fault information of the current tested system; the voice broadcasting module is used for broadcasting the fault information of the current tested system in a voice mode.
With continued reference to fig. 5, as shown in fig. 5, the left graph is an ac/dc ground fault analyzer, the right graph is a detector, wherein 1 is a display screen on the ac/dc ground fault analyzer, 2 is a power interface, 3, 4, 5 and 6 interfaces are used for collecting the voltage of the current system to be tested, 7 is a switch button, 8 is a current collection interface, 9 is a display screen on the detector, 10, 11 and 12 are function keys, respectively corresponding to different test functions, and 6 interfaces are the ground wires of the ac/dc ground fault analyzer, and if the current system to be tested is a dc system, the ground wires of the dc system are connected to the current system; if the current system to be tested is an AC system, the zero line of the AC system is accessed.
When the current tested system is detected to have faults, the fault current of the loop to be tested of the current tested system is detected by using the detector. The current collection interface 8 is connected with a current collector, and the current collector is used for detecting fault current in the loop to be detected, and if the fault current exists in the loop to be detected, the current collector can detect the current value in the current loop to be detected, wherein the current collector can be a sine wave current collector and a square wave current collector. According to the type of the current signal acquired by the corresponding current collector, the obtained digital signal is transmitted to the singlechip for data processing after corresponding filtering and amplifying treatment and analog-to-digital conversion, the digital signal is transmitted to the detector in a waveform form after fast Fourier transform treatment, the detector processes according to the received data by a corresponding algorithm to obtain corresponding fault information, the corresponding fault information is displayed on the display screen 9, and the fault information is broadcasted through the voice broadcasting module.
In this embodiment, the ground fault locating system includes: the system comprises an AC/DC ground fault analyzer and a detector, wherein the AC/DC ground fault analyzer is mainly used for analyzing and judging the insulation condition, the current voltage and other information of the current tested system, and the detector is used for searching and positioning fault points. The detector is connected with the AC/DC ground fault analyzer in a wireless mode. The AC/DC ground fault analyzer sends the collected, detected and calculated information to the detector, and the detector locates the fault point based on the fault information sent by the analyzer and the detected current of the current collector.
The embodiment provides a ground fault locating system, which comprises a detector and an AC/DC ground fault analyzer, and can detect, find and locate the ground fault of the AC/DC system, improve the compatibility and accuracy of the AC/DC ground fault locating system and more comprehensively meet the demands of users.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (9)
1. An ac/dc ground fault analyzer, comprising:
the current detection circuit is used for controlling the change of current so as to detect the change of the voltage to the ground of the current tested system;
the voltage sampling circuit is connected to the current detection circuit and is used for identifying the voltage type and the voltage class of the current tested system, collecting the grounding voltage of the current tested system and carrying out data processing on the grounding voltage of the current tested system;
the grounding resistance calculation module is connected to the voltage sampling circuit and is used for calling corresponding detection algorithms according to different voltage types and voltage grades of the current tested system to calculate the grounding resistance of the current tested system;
the voltage deviation amplitude acquisition circuit is connected to the current detection circuit and is used for acquiring the voltage amplitude of the AC/DC ground fault analyzer and the current measured system ground voltage deviation amplitude;
the singlechip is connected to the current detection circuit, the voltage sampling circuit, the grounding resistance calculation module and the voltage deviation amplitude acquisition circuit, and is used for controlling the current detection circuit, the voltage sampling circuit, the grounding resistance calculation module and the voltage deviation amplitude acquisition circuit and analyzing and calculating the grounding fault of the current tested system;
the current detection circuit includes: operational amplifier IC7 model OPA454, triode T1 model 2N3439, resistor R19, resistor R23, resistor R25, resistor R26, resistor R27, resistor R28, resistor R29, resistor R30, resistor R31, resistor R32, resistor R36, resistor R37, resistor R39, capacitor C35, capacitor C36, capacitor C37, capacitor C38, optocoupler relays U1, U2 and U3 model AQV 259; the pin 3 of the operational amplifier IC7 is connected to the singlechip, the pin 1 of the operational amplifier IC7 is grounded, the pin 6 of the operational amplifier IC7 is connected to the base electrode of the triode T1, the emitter electrode of the triode T1 is connected to the first end of the resistor R30, the first end of the resistor R23, the first end of the resistor R25, the first end of the resistor R26, the first end of the resistor R28 and the first end of the resistor R29, the second end of the resistor R30 is connected to the pin 2 of the operational amplifier IC7, the first end of the resistor R36, the first end of the capacitor C35 and the first end of the capacitor C36, the second end of the resistor R36 is connected to the first end of the resistor R39, the second end of the capacitor C35 and the second end of the capacitor C36 are grounded, the second end of the resistor R23, the second end of the resistor R25, the second end of the resistor R26, the second end of the resistor R28 and the second end of the resistor R29 are connected to the first end of the resistor R31 and the pins 4 of the optocoupler relays U1, U2 and U3, the pins 1 of the optocoupler relays U1, U2 and U3 are respectively connected to the first end of the resistor R19, the first end of the resistor R27 and the first end of the resistor R32, the second end of the resistor R19, the second end of the resistor R27 and the second end of the resistor R32 are respectively connected to a single chip microcomputer, the pins 2 of the optocoupler relays U1, U2 and U3 are respectively connected to the voltage detection connection ports of the AC/DC fault analyzer, the second ends of the resistor R31 are respectively connected to the first ends of the capacitors C37 and C37, a second end of the resistor R37, a second end of the capacitor C37 and a second end of the capacitor C38 are grounded; wherein: the control pins 1 of the optocoupler relays U1, U2 and U3 are respectively connected to the singlechip; the singlechip controls the pin 4 of the optocoupler relay to be connected to the APHASE, BPHASE corresponding to the pin 6 of the optocoupler relay U1, the pin 6 of the optocoupler relay U2 and the pin 3 of the optocoupler relay U3 respectively and the three voltage detection access ports on the AC/DC ground fault analyzer respectively by controlling the high and low levels of the control pin 1 of the optocoupler relay U1, the pin 2 of the optocoupler relay U2 and the pin 6 of the optocoupler relay U3, and when the pin 4 of the optocoupler relay is connected to the three voltage detection access ports on the AC/DC ground fault analyzer, the grounding voltage value of a current tested system can be changed;
the singlechip is used for acquiring a voltage value before the change and a voltage value after the change, the grounding resistance calculation module is used for calculating the current resistance value to the ground of the three voltage detection access ports, and judging whether a current detection system has a fault or not according to the resistance values; and the singlechip controls the real-time display of the voltage amplitude of the AC/DC ground fault analyzer and the voltage deviation amplitude of the current tested system to the ground.
2. The ac-dc ground fault analyzer of claim 1, wherein the voltage sampling circuit comprises: resistor R6, resistor R7, resistor R8, resistor R9, resistor R11, resistor R70, resistor R71, capacitor C18, capacitor C19, capacitor C20, resistor C23, diode D5, diode D6, diode D7 and operational amplifier IC2 of model OP-07;
the first end of the resistor R8 is connected to the pin 3 of the operational amplifier IC2 and the first end of the capacitor C23, the second end of the resistor R8 is connected to the first end of the resistor R7 and the first end of the capacitor C18, the second end of the capacitor C18 is connected to the pin 2 of the operational amplifier IC2, the pin 6 and the first end of the resistor R9, the second end of the resistor R9 is connected to the positive electrode of the diode D5, the negative electrode of the diode D6 and the singlechip, the negative electrode of the diode D5 is connected to +3.3V power supply, the positive electrode of the diode D6 is grounded, the second end of the capacitor C23 is grounded, the pin 7 of the operational amplifier IC2 is connected to +5V power supply, the second end of the resistor R7 is connected to the first end of the resistor R11, the first end of the capacitor C9, the negative electrode of the capacitor C20 and the second end of the resistor C20, the second end of the resistor R7 is connected to the second end of the resistor C7, the second end of the resistor C7 is connected to the second end of the resistor C70, and the second end of the resistor C7 is connected to the resistor C7 is grounded.
3. The ac/dc ground fault analyzer of claim 1, wherein the voltage deviation magnitude acquisition circuit comprises: resistor R20, resistor R21, resistor R22, resistor R24, capacitor C32, capacitor C33, diode D12, diode D13 and operational amplifier IC6 of model OP-07;
pin 3 of the operational amplifier IC6 is connected with the first end of the resistor R21 and the first end of the capacitor C33, the second end of the capacitor C33 is grounded, the second end of the resistor R21 is connected with the first end of the resistor R20 and the first end of the capacitor C32, pin 2 of the operational amplifier IC6 is connected with the second end of the capacitor C32, the first end of the resistor R22 and the pin 6 of the operational amplifier IC6, the second end of the resistor R22 is connected with the positive electrode of the diode D12, the negative electrode of the diode D13 and the first end of the resistor R24, the second end of the resistor R24 is connected with a reference voltage, the negative electrode of the diode D12 is connected with a +3.3V power supply, the positive electrode of the diode D13 is grounded, pin 7 of the operational amplifier IC6 is connected with a +5V power supply, and pin 4 of the operational amplifier IC6 is connected with a-5V power supply.
4. An ac/dc ground fault analyzer as claimed in claim 3, wherein if the second end of the resistor R20 is connected to the first end of the resistor R37, the voltage deviation acquisition circuit acquires the magnitude of the voltage deviation of the measured system to ground;
if the second end of the resistor R20 is connected to the first end of the resistor R39, the voltage deviation acquisition circuit acquires the voltage amplitude of the ac/dc ground fault locating device.
5. A ground fault locating system comprising a detector and the ac-dc ground fault analyzer of any one of claims 1-4;
the detector is connected with the AC/DC ground fault analyzer in a wireless mode.
6. The ground fault locating system according to claim 5, wherein the detector locates the fault point based on the acquired fault information sent by the ac/dc ground fault analyzer.
7. The ground fault locating system of claim 5, further comprising an indicator light for indicating a fault condition of a current system under test.
8. The ground fault locating system of claim 5, further comprising a display screen for displaying fault information of a current system under test.
9. The ground fault locating system according to claim 5, further comprising a voice broadcasting module for voice broadcasting fault information of a currently tested system.
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