CN2121695U - Ground resistance admeasuring apparatus - Google Patents
Ground resistance admeasuring apparatus Download PDFInfo
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- CN2121695U CN2121695U CN 92208327 CN92208327U CN2121695U CN 2121695 U CN2121695 U CN 2121695U CN 92208327 CN92208327 CN 92208327 CN 92208327 U CN92208327 U CN 92208327U CN 2121695 U CN2121695 U CN 2121695U
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Abstract
The utility model discloses a grounding resistance measuring device which relates to the technical field of high pressure, mainly used for measuring the grounding resistance of a power station (factory), and a converting station. An electronic technology is adopted, replacing the hand generator, and the current mutual inductor in the prior art; a frequency selection filtering interference elimination unit is adopted, replacing the phase sensitive rectification filtering unit in the prior art; the comparison of the value of the measure voltage and the value of the reference voltage is adopted; the value of measured grounding resistance is directly read on a digital voltmeter. The grounding resistance measuring device solves the problems that the device with inconvenient operation in the prior art can not be used at a power station (factory) and a converting station, and can not read value due to low interference rejection. The grounding resistance measuring device is characterized in light weight, small volume, and high sensitivity.
Description
The utility model relates to the High-Voltage Technology field, is mainly used in the grounding resistance measurement of power house.
Along with increasing rapidly of electric system capacity, short-circuit current is more and more big, earthing device is more and more big to the influence of safe operation of power system, therefore, to the power house in the high-voltage electric power system (factory), the measurement of the stake resistance of transformer station, become an important process that guarantees safe operation of power system, at present, the instrument of measurement of Grounding Resistance, generally adopt ZC-8 type ground resistance measuring instrument, this instrument is by hand generator, the measured value sampling, phase depending on rectification filtering and current transformation, balanced voltage and relatively through the filtered measured value of phase depending on rectification and balanced voltage, show what plurality of units constituted, wherein phase depending on rectification filtering circuit unit is to adopt three transistors and transistor and resistance to form, original idea is to utilize measuring-signal different with the frequency of undesired signal, measuring-signal is passed through, undesired signal is filtered the influence of eliminating interference, though measuring-signal is different with the frequency of undesired signal, but two signals always have the identical moment of polarity, at this moment undesired signal will be passed through with measuring-signal, although the time of passing through is very short, but a lot (interference current reaches more than ten ampere sometimes because the jam-to-signal measuring-signal is big, measure only tens milliamperes in electric current), in showing, measurement result just includes undesired signal, power house in putting into operation (factory), transformer station, because the electric system three-phase is symmetry not exclusively, in earth neutral system, out-of-balance current is always arranged through the power house (factory), the earthing device of transformer station forms the closed-loop path, so when measurement of Grounding Resistance, just formed the 50HZ interference current, therefore say that ZC-8 type ground resistance measuring instrument antijamming capability is low, can not be used for operating power house (factory), the measurement of substation grounding device stake resistance; Can also adopt " four-electrode method " (being reometer, voltage table method) to measure the stake resistance of power house (factory), transformer station, the capacity that this area engineering technical personnel know the used power-supply device of this method measurement of Grounding Resistance of employing is big, the cost height, it is inconvenient to carry transportation, lead-in wire used during measurement will be by the electric current of 50A, and the current feed cross section is greater than 8mm
2, and to tolerate several kilovolts voltage, because " four-electrode method " exists above-mentioned deficiency, so the in-site measurement stake resistance is difficult to adopt.
The purpose of this utility model is to adopt electronic technology to solve the problem of anti-interference signal, satisfies the requirement of operating power house (factory), transformer station's measurement grounding resistance of transmission, is easy to carry operation and the demonstration value of reading.
The way that realizes the utility model task is that employing battery or rectifier power source are done power supply, utilize electronic devices and components to form the ground resistance measuring instrument with interference free performance, include: power frequency supply rectification unit [1]; Oscillating unit [2]; Power amplification unit [3]; Reference value sampling unit [4]; Measured value sampling unit [5]; Calibration, measurement switch unit [6]; Multiplying power switch unit [7]; Frequency-selective filtering is eliminated interference units [8]; The value of reading display unit [9].
Eliminate operational amplifier in the interference units [8] and the digital voltmeter in the value of the reading display unit [9] by the direct-current power supply oscillating unit [2] after battery or the bridge rectifier in industrial frequency rectifying unit [1], filtering, the voltage stabilizing, power amplification unit [3] and frequency-selective filtering.
Oscillating unit [2] is made of operational amplifier and RC connection in series-parallel oscillator, sine wave signal with direct current vibration output 70～250HZ, export 50～500mA electric current via the power amplification unit [3] that operational amplifier and impedance-matching transformer constitute, as measuring electric current.Power amplification unit [3] connects reference value sampling unit [4] that the measuring resistance by an accurate resistance constitutes and the measured value sampling unit [5] that is made of 4 terminals and tested earthing device (external circuit).Reference value sampling unit [4] output reference voltage 100mv, by calibration, measure " calibration " shelves of switch unit [6], through multiplying power switch unit [7], frequency-selective filtering is eliminated interference units [8], digital voltmeter display reference voltage by the value of reading display unit [9], when demonstration is not 100mv, adjusting power amplification unit [3] is preceding, the potentiometer of oscillating unit [2] output place, in the scope of measuring electric current 50～500mA, select an appropriate value, make reference voltage remain on 100mv, the selection of reference voltage with the value of reading intuitive display, conveniently be principle.Measurement electric current after the reference voltage calibration passes through calibration through the P2 terminal of measured value sampling unit [5] (by tested earthing device-foreign current), measure " measurement " shelves of switch unit [6], multiplying power switch unit [7] through 3 groups of double-pole double-throw key switchs and multiplying power resistance formation inputs to the frequency-selective filtering elimination interference units [8] that is made of the passive double T of symmetry, potential double T and active double-t circuit again, the undesired signal of direct current and 50HZ equifrequency filter is filtered, and the stake resistance actual value of tested earthing device is shown by the digital voltmeter of the value of reading display unit [9].The value of reading display unit [9] is made of coupling capacitance, bridge rectifier circuit, capacitor divider resistance and potentiometer and digital voltmeter.Can also connecting a resistance value and be in the reference value sampling unit [4] accurately on digital voltmeter, the multiplying power resistance of 100 times of inverses of resistance R 22 makes digital voltmeter directly read tested grounding resistance.
The utility model employing electronic technology has replaced the hand generator of prior art, current transformer; The frequency-selective filtering that adopts active double T, passive double T, potential double T and integrated operational amplifier to constitute is eliminated interference units and has been replaced phase depending on rectification filter unit of the prior art; Adopt tested magnitude of voltage and reference voltage value relatively, directly the method for reading tested grounding resistance at digital voltmeter has replaced utilizing in the prior art Current Transformer Secondary side adjustable resistance adjustment joint and the identical balanced voltage of the tested voltage of primary side, by the voltage table supervision again by the method for the adjustable resistance value of reading.Solved prior art because antijamming capability is low, the power house that can not be in operation (factory), transformer station uses and the value of reading, the problem of inconvenient operation.The utlity model has in light weight, volume is little, and because the wide and feasible measurement of measurement electric current adjustable extent is highly sensitive, because available outer attached powered battery, still can use at the AC-less power place, not limited by environmental baseline, use general colloid electric wire to get final product during measurement, applied widely, it is little to consume energy, use the utility model to measure operating power house (factory), the stake resistance of substation grounding device has thoroughly changed the measuring method of prior art, unnecessary human and material resources have been avoided, the loss of fund.
Below in conjunction with accompanying drawing the utility model is done step explanation:
Fig. 1, ground resistance measuring instrument theory diagram;
Fig. 2, ground resistance measuring instrument principle assumption diagram;
Fig. 3, ground resistance measuring instrument element tie lines and arrangenent diagram;
Fig. 4, ground resistance measuring instrument case panel synoptic diagram.
See that ground resistance measuring instrument illustrated in figures 1 and 2 is to do power supply by battery (empty frame) or power frequency supply (real frame), (D2 is 0 to D5 to rectifier bridge in industrial frequency rectifying unit [1], 5A/25V), filtering (electrochemical capacitor C24 is 1000 μ F/25V to C27), (three terminal regulator Y1 is 7818 types in voltage stabilizing, Y2 is 7809 types to Y4, links Y2 and is respectively direct-current power supply oscillating unit [2] behind the 1 μ F/25V to three capacitor C 1 to C3 of Y4, the operational amplifier that power amplification unit [3] and frequency-selective filtering are eliminated in the interference units [8] (is respectively U2, U3, U1) and the digital voltmeter in the value of the reading display unit [9].
Oscillating unit [2] is by operational amplifier U2(LM741) and RC connection in series-parallel oscillator (wherein R12 is 15K Ω, R1321K Ω, R14100K Ω, R15330K; Electrochemical capacitor C17, C18 is 100 μ F/25V) constitute, sine wave signal with direct current vibration output 70～250HZ, via operational amplifier U3(LA4265) and the power amplification unit (3) that constitutes of impedance-matching transformer is wherein: (resistance R 17 is 3,3K Ω, R18 is 45K Ω, electrochemical capacitor C19 is 470 μ F/25V, Polyvinylchloride capacitor C 20 is 0,1 μ F/63V, electrochemical capacitor C21 is 1 μ F/25V, C22 is 47 μ F/25V, C23 is 470 μ F/25V, the turn ratio of transformer is 120 circles/450 circles, 5W output 50～500mA electric current is as measuring electric current.Power amplification unit [3] links that (R22 is the reference value sampling unit [4] that constitutes of 1 Ω and the measured value sampling unit [5] that is made of 4 terminals (C1, P1, P2, C2) and tested earthing device (external circuit) by the measuring resistance of an accurate resistance.Reference value sampling unit [4] output reference voltage 100mV, by the calibration that constitutes by the single-pole double throw toggle switch, " calibration " shelves of measuring unit [6], through multiplying power switch unit [7], frequency-selective filtering is eliminated interference units [8], by the digital voltmeter demonstration of the value of reading display unit [9].Measurement electric current after the reference voltage calibration is through the P2 terminal of measured value sampling unit [5] (by tested earthing device-external circuit), by the calibration that constitutes by the single-pole double throw toggle switch, " measurement " shelves of measuring unit [6], (R19 is 495K Ω through 3 groups of double-pole double-throw key switchs and multiplying power resistance again, R20 is 5K Ω, R21 is 45K Ω) to input to by the passive double-t circuit Polyvinylchloride of symmetry capacitor C 7 be 0.22 μ F/63V for the multiplying power switch unit [7] that constitutes, C8 is 0.022 μ F/63V, C11 is 0.242 μ F/63V, resistance R 4 is 15K Ω, R5 is 150K Ω, R6 is 13K Ω), potential double-t circuit (Polyvinylchloride capacitor C 9, C10, be 0,022 μ F/63V, C12 is 0.044 μ F/63V, electrochemical capacitor C13 is 1 μ F/25V, and R7 is 100K Ω, R8 is 120K Ω, R9 is 75K Ω, R10 is 10K Ω) and active double-t circuit (operational amplifier U
1For LM741, Polyvinylchloride capacitor C 4, C5, be that 0,022 μ F/63V, C6 are that 0.022 μ F/63V, R1 are that 70K Ω, the R2 frequency-selective filtering that to be 6K Ω, R3 constitute for 5.4K Ω is eliminated interference units [8], the equifrequent undesired signal of direct current and 50HZ is filtered, and the stake resistance actual value of tested earthing device is shown by the digital voltmeter of the value of reading display unit [9].The value of reading display unit [9] is to be made of coupling capacitance (Polyvinylchloride electric capacity 0.22 μ F/63V) bridge rectifier circuit (rectifier bridge D1 is 1A/25V), capacitor (Polyvinylchloride capacitor C 15, C16 are respectively 0,022 μ F/63V, 330PF/63V), divider resistance (R11 is 41K Ω) and potentiometer (W1 is 10K Ω, 0.25W, and W2 is 1K Ω, 0.25W) and digital voltmeter (G is UP316).
See Fig. 3 and ground resistance measuring instrument shown in Figure 4, shown in Figure 3 is the position of element on printed circuit board (PCB), Fig. 4 is the case panel synoptic diagram, shell dimension of the present utility model is long 170MM, wide 100MM, high 170MM, adopt aluminum alloy frame, sheet iron baking vanish or plastic spraying, the shell plates face is an aluminium sheet, [10] be power switch (employing toggle switch) in the power frequency supply rectification unit [1], [11], [12] are respectively calibration coarse adjustment potentiometer W1 and the calibration fine tuning potentiometer W2 in the value of the reading display unit [9].The utility model all adopts the resistance of 0.125W.
Claims (9)
1, a kind of field of high-voltage technology that relates to, be mainly used in the ground resistance measuring instrument of power house (factory), transformer station, include: housing, battery or power frequency supply rectification unit [1] and measured value sampling unit [5] is characterized in that battery or power frequency supply rectification unit [1] are connected with oscillating unit [2], power amplification unit [3], frequency-selective filtering elimination interference units [8] and the value of reading display unit [9].
2, ground resistance measuring instrument according to claim 1, it is characterized in that the oscillating unit [2] that constitutes by operational amplifier and RC series and parallel oscillator, the sine wave signal of the direct current vibration output 70 to 250HZ that battery or power frequency supply rectification unit [1] are supplied with.
3, ground resistance measuring instrument according to claim 1, it is characterized in that the power amplification unit [3] that is made of operational amplifier and impedance-matching transformer, output 50 to 500MA electric currents are as measuring electric current after the sine wave signal processing and amplifying of will oscillating unit [2] supplying with.
4, ground resistance measuring instrument according to claim 3, it is characterized in that connecting through power amplification unit [3] output terminal, the reference value sampling unit [4] that constitutes by the measuring resistance (R22) of an accurate resistance, by regulating the preceding potentiometer (W3) of power amplification unit [3] input end, in measuring electric current 50 to 500MA, select an appropriate value, the measurement electric current that makes this numerical value produces a reference voltage value during by resistance (R22).
5, ground resistance measuring instrument according to claim 4, it is characterized in that the calibration that is connected with measured value sampling unit [5] by reference value sampling unit [4], measuring switch unit [6] is made of the single-pole double throw toggle switch, when switch is thrown into " calibration " shelves, the reference voltage of sending here through reference value sampling unit [5], eliminate interference units [8] by multiplying power switch unit [7] and frequency-selective filtering, show by the value of reading display unit
6, ground resistance measuring instrument according to claim 5, it is characterized in that by calibration, the multiplying power switch unit [7] of measuring switch unit [6] connection is made of 3 groups of double-pole double-throw key switchs and multiplying power resistance, measurement electric current after the reference voltage calibration is through the external circuit (being tested earthing device) of measured value sampling unit [5], eliminate interference units [8] by multiplying power switch unit [7] and frequency-selective filtering, show by the value of reading display unit [9].
7, according to claim 1 or the described ground resistance measuring instrument of claim 5, it is characterized in that the frequency-selective filtering elimination interference units [8] that is connected by multiplying power switch unit [7] is made of the passive double-t circuit of symmetry, potential double-t circuit and active double-t circuit, measured signal is eliminated interference units [8] by frequency-selective filtering, the undesired signal of direct current and 50HZ frequency is filtered, 70 to 250HZ measured signal is shown by the value of reading display unit [9].
8, ground resistance measuring instrument according to claim 7, it is characterized in that by coupling capacitance, bridge rectifier circuit, the value of the reading display unit [9] of capacitor and divider resistance and digital voltmeter formation is by the grounding resistance that recently show measurement of tested magnitude of voltage with the reference voltage value of measuring preceding " calibration ".
9, ground resistance measuring instrument according to claim 8, it is characterized in that digital voltmeter connects the multiplying power resistance that a resistance value is 100 times of inverses of accurate resistance R 22 in the reference value sampling unit [4] in the value of the reading display unit [9], make digital voltmeter directly read tested grounding resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92208327 CN2121695U (en) | 1992-04-28 | 1992-04-28 | Ground resistance admeasuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92208327 CN2121695U (en) | 1992-04-28 | 1992-04-28 | Ground resistance admeasuring apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2121695U true CN2121695U (en) | 1992-11-11 |
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ID=4953857
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 92208327 Granted CN2121695U (en) | 1992-04-28 | 1992-04-28 | Ground resistance admeasuring apparatus |
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| Country | Link |
|---|---|
| CN (1) | CN2121695U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102645577A (en) * | 2012-05-03 | 2012-08-22 | 上海大帆电气设备有限公司 | Digital frequency selection measuring system capable of resisting one hundred thousand times of interference |
| CN102859372A (en) * | 2010-04-19 | 2013-01-02 | Abb技术有限公司 | Method and arrangement for determining impedance values |
| CN104698284A (en) * | 2013-12-05 | 2015-06-10 | 珠海格力电器股份有限公司 | Detection tool for detecting grounding resistance of electric tool or electric heating tool |
| CN107831369A (en) * | 2017-12-19 | 2018-03-23 | 成都信息工程大学 | A kind of grounding resistance monitor instrument with self-test and correction |
-
1992
- 1992-04-28 CN CN 92208327 patent/CN2121695U/en active Granted
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102859372A (en) * | 2010-04-19 | 2013-01-02 | Abb技术有限公司 | Method and arrangement for determining impedance values |
| CN102859372B (en) * | 2010-04-19 | 2015-04-01 | Abb技术有限公司 | Method and arrangement for determining impedance values |
| CN102645577A (en) * | 2012-05-03 | 2012-08-22 | 上海大帆电气设备有限公司 | Digital frequency selection measuring system capable of resisting one hundred thousand times of interference |
| CN104698284A (en) * | 2013-12-05 | 2015-06-10 | 珠海格力电器股份有限公司 | Detection tool for detecting grounding resistance of electric tool or electric heating tool |
| CN104698284B (en) * | 2013-12-05 | 2018-01-19 | 珠海格力电器股份有限公司 | Detection tool for detecting grounding resistance of electric tool or electric heating tool |
| CN107831369A (en) * | 2017-12-19 | 2018-03-23 | 成都信息工程大学 | A kind of grounding resistance monitor instrument with self-test and correction |
| CN107831369B (en) * | 2017-12-19 | 2020-07-03 | 成都信息工程大学 | Grounding resistance monitor with self-checking and correcting functions |
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| CF01 | Termination of patent right due to non-payment of annual fee |