CN2092104U - Single-phase grounding detector of low-current grounding system - Google Patents

Abstract

The utility model relates to a malfunction detector in the electric power system, particularly a single-phase grounding detector of a low-current grounding system. The utility model comprises a housing, an inner circuit structure and a corresponding panel. The utility model is characterized in that the inner circuit structure comprises a multimeter, an interface loop, a detection selecting loop, and a filtering anti-jamming loop which have the function of measuring the voltage and the frequency of alternating current. The utility model has the advantage that the detector can detect the grounding circuitry of the single-phase grounding fault of the low-current grounding and estimate the grounding distance under the condition of non-power failure.

Description

Single-phase grounding detector of low-current grounding system

The utility model belongs to the pick-up unit of single-phase earthing of small current earthing system in the failure detector in a kind of electrical network circuit, particularly electrical network circuit.

In the small current neutral grounding electric system, singlephase earth fault takes place often, need multichannel outlet on the ground strap is had a power failure one by one according to traditional disposal route, search faulty line, cause user's unplanned power failure, influence the ordinary production of factory and the people's life, bring unnecessary economic loss to country, if run into two homophase ground connection simultaneously, frequency of power cut will be more, have a strong impact on power supply reliability and electricity sales amount, though market has the microcomputer type fault locator, but which bar outlet ground connection is its principle judges for each bar outlet zero sequence power direction relatively, and energy measurement ground distance not, and program is complicated in the Installation and Debugging process, need there be the voltage transformer secondary loop to insert, also need in tested electrical network, arc to be installed, and price is higher, therefore still can not effectively solves the problem of earthing wire-selecting and rapid handling failure.

The purpose of this utility model has been to provide a kind of pick-up unit of single-phase grounded malfunction in grounded system of low current, to replace the microcomputer type detector, this device can be under situation about not having a power failure, measure faulty line, and can estimate and ground distance, fault handling is speeded up, also alleviated track walker's labour intensity simultaneously.

Detailed technology scheme of the present utility model: a kind of pick-up unit of single-phase earthing of small current earthing system, it comprises shell, internal circuit configuration and corresponding panel, be characterised in that said internal circuit configuration is to install interface loop additional by containing the multimeter of measuring alternating voltage and frequency functionality, Selected Inspection loop and the anti-interference loop of filtering are formed; Said interface loop is to introduce 15 leads by circuit-under-test by panel interface in device, wherein the 15th is common ground, be connected to multimeter COM end, the 1-7 line is connected to respectively on the I-VII options button lower left node in Selected Inspection loop, and the 8-14 line is connected to respectively on the I-VII options button upper left side node; Said Selected Inspection loop is made up of 7 options buttons and a switch key of constituting 2 * 7 kinds of selections, 7 options button lower left switching nodes also are attached to switch key right side node a, its upper left side switching node also is attached to switch key right side node b, switch key c end is the output terminal in Selected Inspection loop, and the anti-interference loop of its extension line and filtering joins; The anti-interference loop of said filtering is by RC resistance capacity filter and three grades of two T-shape filtering circuit be combined intos of typical case, its output terminal is connected to options button I-VII lower right switching node, after parallel connection, be connected to options button VII upper right side node, and connect with the A.C. voltmeter and the frequency meter of multimeter.Ri=1.6K Ω in the anti-interference loop of above-mentioned filtering, Ci=0.047 μ F removes the above electromagnetic interference (EMI) of 30KHz through capacitance-resistance filter, again through three grades of two T-shape filtering circuit frequency-selectings, elimination 50Hz, 150Hz and 250Hz frequency and three times, quintuple harmonics interference, filter out because the electromagnetic resonance signal that ground connection causes, one-level T-shape circuit satisfies C1=C2=C3=C4 in this circuit, R1=R2=2R3, its frequency filtering f1=1/ (2 π R1C1)=50Hz then reaches the purpose of elimination 50Hz signal; Secondary T-shape circuit satisfies C5=C6=C7=C8, R4=R5=2R6, its frequency filtering f2=1/ (2 π R ₄C ₅)=250Hz then reaches the purpose of elimination 250Hz signal, three grades of T-shape circuit C9=C10=C11=C12, R7=R8=2R9, its frequency filtering f3=()/(2 π R ₇C ₉)=150Hz then reaches the purpose of elimination 150Hz signal.

Using method of the present utility model and principle: original ultra-high-tension power transmission line inserts one " zero-sequence current-electric pressure converter " by current transformer in tested electric system, be about to the current transformer zero line and disconnect this annex of access, and this converter is installed in the outlet terminal case, and with cable 15 line interfaces that 14 high-voltage terminal residual voltage signals reach master-control room central signaling panel and the utility model device are linked (wherein one for shared ground wire), 15 line interfaces and options button in the device link, add switch key and constitute 2 * 7 kinds of selections, article 14, lead-in wire is admitted to the Selected Inspection loop by interface, and the residual voltage signal that the Selected Inspection loop is connected carries out filtering and anti-interference process, to filter the height that causes because of load asymmetric residual voltage that causes and extraneous factor, low frequency electromagnetic disturbs, afterwards, filtered signal is measured its alternating voltage respectively, its value the maximum and this maximal value join other outlet (voltage) value sum person greater than ground strap and are ground path, after finding out ground path, by device described in the utility model the zero sequence resonance signal of this circuit is surveyed its oscillation frequency again, " resonance frequency and the ground distance relation curve " that contrast theory then and experiment are derived, can find the line-to-ground distance, and instruct the track walker to search fast and handling failure with this.

Superiority of the present utility model: 1, this device can be measured the ground path of single-phase grounded malfunction in grounded system of low current under situation about not having a power failure, and can estimate and ground distance, so reduced the fault outage number of times, and accelerated fault handling speed, also alleviated track walker's labour intensity simultaneously; 2, owing to abandoned the detection method of traditional measurement zero sequence power direction, phylogenetic micro-resonance signal when transferring to measure ground connection, make that this pick-up unit line construction is simple, use the microcomputer type device of similar functions can reduce expense greatly, and can remedy the microcomputer deficiency of energy measurement ground distance not still in the use; 3, Installation and Debugging are convenient, compare with the microcomputer type pick-up unit, need not the voltage transformer secondary loop is inserted, and whether tested electrical network is equipped with arc, to this device also not influence; 4, this device volume little, in light weight (1.5Kg), function complete (can measure AC and DC voltage, electric current, resistance, frequency etc.), degree of accuracy height, easy to carry, practical.

Further specify present technique below in conjunction with drawings and Examples of the present utility model.

Accompanying drawing one is the principle of work block diagram of the related device of the utility model;

Wherein A is pairing is tested electric system, and B is annex (zero-sequence current-electric pressure converter), and C is a contained circuit in the device, and D is an automatic heating circuit, and E is former function of multimeter.

Accompanying drawing two is the related manipulated or operated apparatus of the utility model.

Wherein the 1-15 in the figure is 15 line interfaces, and I-VII is an options button, and VIII is a switch key, Be the A.C. voltmeter of multimeter, Hz is the frequency meter of multimeter, and V-Hz is the multimeter input end.

Accompanying drawing three is the local circuit of the related device of the utility model--filtering antijamming circuit figure.

Wherein Vi is an input voltage, and Ri is for going into to hold filter resistance; Ci is for going into to hold filter capacitor, and C1-C12 is for constituting two " T " filter circuit electric capacity, and R1-R9 is for constituting two " T " filter circuit resistance, V.Be output voltage.

Accompanying drawing four is the panel synoptic diagram of the related device of the utility model.

Wherein: 1 is power switch, and 2 is 15 line interfaces, and 3 are the outlet options button, and 4 is switch key, and 5 is function key, and 6 is digital display screen, and 7 is the range key, and 8 is the multimeter input end.

" resonance frequency and ground distance relation curve " figure that accompanying drawing five is contrasted when being of the present utility model the use.

Embodiment: a kind of pick-up unit of single-phase earthing of small current earthing system of electrical network circuit, it is just like housing face-plate and the figure two and the circuit structure shown in the figure three of figure four, optional commercially available ESCORT EDM-2347 type 4 1/2 figure places are numerous with table during making, can install the anti-interference loop of filtering shown in the figure three within it additional, to eliminate the zero sequence current signal that three-phase asymmetric load causes, and install 15 line interfaces shown in the figure two and Selected Inspection loop additional, in addition, the optional commercially available 150VA single transformer of annex " zero-sequence current-electric pressure converter " that cooperates this device to use, it is contained in the outlet terminal case, with cable signal is reached the master-control room central signaling panel, by 15 line interfaces outlet of 35KV7 bar and 10KV7 bar outlet (i.e. 14 outlets) are inserted this pick-up unit, finished system's connection.

Ri=1.6K Ω in the filtering antijamming circuit in the said apparatus, Ci=0.047 μ F, remove the above electromagnetic interference (EMI) of 30KHz through capacitance-resistance filter, but value is in three grades of T-shape circuit: one-level T-shape circuit C1=C2=C3=C4=0.1MF, R1=R2=31.847K Ω=2R3, R3=15.9K Ω=R ₁1/2, frequency filtering f1=1/ (2 π R ₁C ₁)=50Hz; C5=C6=C7=C8=0.1MF in the secondary T-shape circuit, R4=R5=2R6=6.366K Ω, its frequency filtering f2=1/ (2 π R ₄C ₅)=250Hz; Three grades of T-shape circuit C9=C10=C11=C12=0.1MF, R7=R8=2R9=10.610K Ω, its frequency filtering f3=1/ (2 π R ₇C ₉)=150Hz.

Claims (2)

1, in a kind of electrical network circuit pick-up unit, the pick-up unit of single-phase earthing of small current earthing system particularly, it comprises shell, internal circuit configuration and corresponding panel, be characterised in that said internal circuit configuration is to install interface loop additional by containing the multimeter of measuring alternating voltage and frequency functionality, Selected Inspection loop and the anti-interference loop of filtering are formed; Said interface loop is to introduce 15 leads by circuit-under-test by panel interface in device, wherein the 15th is common ground, be connected to multimeter COM end, the 1-7 line is connected to respectively on the I-VII options button lower left node in Selected Inspection loop, and the 8-14 line is connected to the I-VII options button upper left side node respectively; Said Selected Inspection loop is made up of 7 options buttons and a switch key of constituting 2 * 7 kinds of selections, 7 kinds of options button lower left switching nodes also are attached to switch key right side node a, its upper left side switching node also is attached to switch key right side node b, switch key c end is the output terminal in Selected Inspection loop, and the anti-interference loop of its extension line and filtering joins; The anti-interference loop of said filtering is by RC resistance capacity filter and three grades of two T-shape filtering circuit be combined intos of typical case, its output terminal is connected to options button I-VII lower right switching node, after parallel connection, be connected to options button VII upper right side node, and connect with the alternating voltage retaining and the frequency retaining of multimeter.

2,, be characterised in that its Ri=1.6K Ω of RC resistance capacity filter that is adopted in the anti-interference loop of filtering in its internal circuit structure, Ci=0.047MF by the said pick-up unit of claim 1; Three grades of T-shape filtering circuits that adopted, C1=C2=C3=C4 in its one-level T-shape circuit, R1=R2=2R3, and frequency filtering f1=50Hz, C5=C6=C7=C8 in the secondary T-shape circuit, R4=R5=2R6, its frequency filtering f2=250Hz, C9=C10=C11=C12 in three grades of T-shape circuit, R7=R8=2R9, its frequency filtering f3=150Hz.

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