CN204514974U - For the portable lightning current generation device of earthing device impact impedance test - Google Patents
For the portable lightning current generation device of earthing device impact impedance test Download PDFInfo
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- CN204514974U CN204514974U CN201520148418.7U CN201520148418U CN204514974U CN 204514974 U CN204514974 U CN 204514974U CN 201520148418 U CN201520148418 U CN 201520148418U CN 204514974 U CN204514974 U CN 204514974U
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Abstract
The utility model discloses a kind of portable lightning current generation device for the test of earthing device impact impedance, comprise generator and the chamber of lightning current generator major loop; Rectification silicon stack D, charging resistor R1 and divider are connected on the output terminal of step-up transformer T2; Storage capacitor C is in parallel with divider; Discharge switch S one end connects the positive pole of storage capacitor C, the other end connects one end of adjustable wave regulating resistor R2, the other end of adjustable wave regulating resistor R2 connects adjustable harmonic inductance L one end, and the other end of adjustable harmonic inductance L connects grounded screen to be measured by earthing test Current injection points; The surrounding of grounded screen to be measured is furnished with earthing test backflow pole and reference voltage pole; Earthing test backflow pole is connected to the negative pole of the storage capacitor C of lightning current generator major loop.This device can simulaed inductance effect and soil spark discharge effect really, tests out impulse earthed resistance really.
Description
[technical field]
The utility model belongs to Grounding Technology of Modern Power System field, particularly a kind of portable lightning current generation device for the test of earthing device impact impedance.
[background technology]
Electric system has the ground connection needs of the various ways such as work, lightning protection, safety, and they ensure power system security, the indispensable pith of stable operation.Along with the realization of transferring electricity from the west to the east and the north and south national network strategy of confession mutually, China's power industry will keep increasing fast in following 15 ~ 20 years, need to build super (spy) high voltage substation of a large amount of 330kV, 500kV, 750kV and 1000kV and shaft tower, simultaneously in order to ensure in operation of power networks process, the safety of staff and electrical equipment, needing is specially a large amount of ground connection facility of these transformer stations and shaft tower construction.Earthing device impact impedance testing research, just in order to design, building, safeguard the ground connection facility of electric system better, and expansion is very urgent, and the work be of great significance.
Findding out earthing device impact impedance characteristic, is to design earthing device better.The operating experience of electric system shows, most of transmission line of electricity accident is all because transmission line of lightning strike or shaft tower cause caused by tripping operation.Such as, show according to electric network fault statistic of classification, in the area that China's trip-out rate is higher, in total tripping operation number of times that high-tension line runs, by being struck by lightning, the number of times caused accounts for 40 ~ 70%, and this brings huge economic loss by society.Operating experience both domestic and external and theoretical analysis show, effectively reducing pole tower ground resistance is the effective measures the most improving transmission line of electricity direct lightning strike protected effect.In the lightning protection properties design of overhead line structures, the transient state impedance ground value of its earthing device, directly has influence on the lightning protection effect of circuit.During transmission line of electricity Lightning Protection Analysis at home and abroad calculates, electric power line pole tower earthing device transient state impedance ground only adopts the lumped parameter resistance of particular value to simulate usually, such as, the Analysis of Grounding softwares such as the CDEGS be used widely at present still cannot consider the nonlinear characteristic in lightning stroke process caused by soil ionization.And in fact, under dash current effect, the transient state impedance ground of earthing device is dynamic change in time, and present complicated nonlinear characteristic.
Power transmission line corridor is inevitably through high soil resistivity mountain area.Owing to earthing device being equivalent to lumped parameter resistance to process in traditional falling in resistance thinking, thus from the angle of static state, the measure improving earthing device diffusing performance can only be proposed.And these traditional measures are when soil resistivity is very high, its resistance-reducing efficiency is limited, not obvious to the improvement of line thunder protection performance.If can test exactly, and calculate earthing device impact dynamic process, just can for the dash current wave head period of causing lightning stroke flashover the most serious, from improving the angle of Electric Field Distribution dash current wave head period ground to improve the impact diffusing efficiency of earthing device, reduce the transient state impedance ground of dash current wave head period.
In addition, dash current in the process of soil diffusing, along with the increase soil resistivity of electric field intensity in soil can decline to some extent, presents non-linear electric phenomenon through earthing device.Meanwhile, when the electric field intensity of earthing pole surrounding soil exceedes the breakdown field strength of soil, in earthing pole surrounding soil, strong spark discharge can be produced, near earthing pole, define an irregular region of discharge.Therefore, the calculating of earthing device of power transmission line transient state impedance ground just must reflect this dynamic physical processes exactly.The relation that diffusing simulation test experiment obtains spark discharge region and grounding device constructions is impacted by a large amount of earthing device, and obtain earthing device impact impedance characteristic by the test of soil nonlinear characteristic, finally just can obtain the result of calculation of realistic physical process.
If the impact impedance characteristic test carrying out earthing device that can be easy, and correctly set up the dynamic perfromance computation model of earthing device of power transmission line under dash current effect, be not only and calculate the dynamic electric field problem that there is ionization phenomena and medium nonlinear characteristic and provide theoretical analysis method, also for Accurate Prediction transmission line of electricity lightning protection effect, calculate lightning surge and provide powerful support.The portable lightning current generation device of earthing device impact impedance test has important theory significance and engineer applied is worth, and can provide new resolving ideas for the practical challenges that power department is in the urgent need to address.
The impact characteristics of earthing device is significant to lightning Protection Design, from last century in early days, lot of domestic and foreign scholar has just carried out large quantifier elimination to it, also has some significant achievements, generally speaking, these researchs can be roughly divided into experimental study and the large class of theoretical simulation research two.
(1) experimental study
According to the difference of test condition, the experimental study of earthing device impact characteristics can be divided into on-the-spot real model experiment and laboratory simulation experiment two large classes.
On-the-spot real model experiment is exactly the input with impulse current generator simulation lightning current, carries out impulse test, measure its impact characteristics to real grounding body.In practice, electric current during thunderbolt shaft tower is very large, on-the-spot real model experiment wants to obtain big current, just need jumbo impulse current generator, and want the capacity improving impulse current generator, those are under existing technical conditions, inevitably will increase the volume of generator, again because the edaphic condition of on-the-spot real model experiment artificially can not control, want the data under acquisition different soil, just constantly move heavy impulse current generator.And along with the raising of generator capacity, the danger of test also can further increase.So, be not only the impulse current generator very labor intensive material resources of ship bulky, and the safety problem brought when Large Copacity impulse current generator is done experiment is also more complicated.Because present stage on-the-spot real model experiment has larger limitation, all the time relevant data are all fewer, just for the result of proof theory derivation.
The analogue experiment method of electric field has two kinds, and one is geometric modelling, and one is mathematical simulation.What extensively adopt in the test of earthing device is Geometric modeling.Geometric modeling is a kind of physical simulation be based upon on similarity, and the electric current, soil resistivity etc. of the physical dimension of earthing device, the depth of burying, injection earthing device by respective scale compression, are tested by it in simulation pond.The maximum benefit of simulated experiment facilitates exactly, only needs little investment, just experiment porch can be set up, and can Long-Time Service.Wanting to change the physical dimension of grounding body or soil resistivity in addition in an experiment all than being easier to, the impulse test under multiple condition can be simulated easily.
But the limitation of simulated experiment is also obvious.If the engineer's scale of all physical dimensions of soil model and grounding body is n, so according to the principle of similitude, the dash current injected compared to real model experiment electric current should reduce n doubly so the amplitude of waveform should reduce n doubly, and the wave head time also will reduce n doubly accordingly.Only will bring the problem of two aspects like this, first after current amplitude reduces, the electric field intensity of each point in soil can be made accordingly to reduce a lot, perhaps the soil Spark Discharges that so may occur under real model experiment condition, would not occur when simulated experiment; Secondly, want to be reduced n the wave head time of input current doubly, improve the steepness of waveform, implement difficulty also not little.In addition, the size reducing soil model can not reduce the size of soil particle, thus simulated experiment also just can not simulate the diffusing situation under different soils particle conditions, is also just difficult to the soil Spark Discharges reflecting that earthing device occurs under dash current really.Simulated experiment can reflect some rule of earthing device impact characteristics qualitatively, is but difficult to the impact characteristics accurately reflecting earthing device from quantitative angle.
(2) theoretical simulation research
Compared to the experimental study of earthing device impact characteristics, the development of its theoretical research is many rapidly, especially along with the development of computer technology, makes mass computing become easy, has promoted the development of theory calculate further.At present, the emulation for earthing device transient characterisitics mainly contains following several: transmission line theory, Circuit theory, Theory of Electromagnetic Field, Finite Element Method etc.
1) transmission line theory
Meliopoilos A.P, Moharam M.G, the people such as Mazzettie C. and Veca G.M. propose in last century the scheme carrying out analogue ground device transient characterisitics by the theory of transmission line when the eighties.The response of horizontal grounding objects under dash current is used as the wave process had on the transmission line of distribution parameter and is processed by transmission line theory, is a kind of method of time domain.This method is relatively suitable for for horizontal grounding objects, but just inapplicable for the earthing device of other structures, the earthing device of such as Grounding Grids or labyrinth.
2) Circuit theory
Method based on Circuit theory grounding body is modeled to the π type equivalent circuit be made up of lumped parameter R-L-C-G to calculate its shock response, and this is one very directly method.This method is not too high to the demand of computational resource, and result of calculation is also acceptable.
The defect of Circuit theory is, the situation for complicated grounding body deals with cumbersome, conveniently calculates, and usually will take the computing formula simplified, so just have impact on the precision of result of calculation.Some scholar domestic has carried out the research of this respect, but is much all confined to the grounding body of level, or have ignored the impact of soil flashing electric discharge non-linear hour characteristic, or have employed the model simplified very much.In addition, some scholar utilizes the impact characteristics of circuit simulating software to grounding body to be studied in conjunction with Theory of Electromagnetic Field, the defect of circuit simulating software is the iterative computation that cannot complete parameter automatically, people is needed to be the parameter calculating each iteration, use just very inconvenient like this, and easily introduce artificial error.
3) Theory of Electromagnetic Field
Theory of Electromagnetic Field is with Maxwell system of equations for starting point, considers the electromagnetic coupled between conductor, and then analysis grounding device transient characterisitics.Along with the develop rapidly of computer technology, Theory of Electromagnetic Field can better use transient approach, numerical integration, Sommerfeld integration and FFT technology to carry out analytical calculation to the transient characterisitics of grounding body.Numerical computation method based on electromagnetic field has a lot, such as finite element method, boundary element method, method of finite difference, method of moment etc.Anton Habjanic and Mladen Trlep utilizes Finite Element Method Simulation to calculate the Potential distribution on earth's surface when Grounding Grids generation fire is provided electric, and with not considering that the situation of spark discharge has done contrast, professor Zhou Bihua of Polytechnics of PLA is analyzed the time domain specification of grounding body under dash current effect by Finite-Difference Time-Domain Method (FDTD), doctor Zhang Bo of North China Electric Power University to utilize the Electromagnetic Calculation methods analyst frequency domain characteristic of grounding net of transformer substation based on method of moment, and University Of Chongqing have also been made large quantifier elimination in this respect.
The advantage of Finite Element Method is the situation of the extraordinary process soil layering of energy, but can be easy to cause ill-condition matrix in the significant change of soil boundary resistivity, affects computational accuracy when numerical solution.The method of frequency domain is then not easy to process non-linear effects when soil punctures, and have impact on the practicality of model.In addition, the requirement of method to computational resource based on Theory of Electromagnetic Field is higher, relatively more effective when the simple grounding body of calculating, for the large-scale earthing device of complexity, then needs the computing time of at substantial.
Carrying out preventing thunder earthing design according to the characteristic of lightning current itself is the basis reducing lightning strike accident.In research work outside Current Domestic, a lot of scholar carries out the project navigator of lightning protection often according to the experience of power-frequency earthing, but compared to power current, lightning current but has the character of its uniqueness, topmost have following 2 points: first, the frequency of lightning current is very high, this just makes the impact of earthed system inductive effect under dash current much bigger compared to the impact under power frequency, therefore, under dash current, the inductive effect of earthed system must be considered, and under power current, the inductive effect of earthed system is usually left in the basket.Second, the amplitude of lightning current is quite high, when lightning current is in ground during diffusing, the field intensity of its current field is high enough to the soil around earthing pole is ionized, and produces spark discharge effect, thus changes the electrical characteristics of neighbouring soil, if do not considered, seriously will lose contact with reality, but under power frequency, then be difficult to produce so high electric field intensity.In the simulation study of present stage, a lot of scholar have ignored the impact of these two factors, but no matter neglects which factor, and the impact characteristics of the result of design of Simulation and actual earthing device all can be made to produce certain deviation.In addition, because the difficulty of real model experiment is large, cost is high, and make the result of a lot of theoretical simulation all can not get effective checking, its practicality has also just been had a greatly reduced quality.
At present, adopting the lumped parameter resistance of particular value to carry out the method that analogue ground device carries out transmission line of electricity Lightning Protection Analysis, is cause Lightning Protection Analysis result to differ larger one of the main reasons with actual motion statistics.In sum, the tolerance lightning impulse level obtaining earthing device of power transmission line is the most direct, and most effective method carries out on-the-spot test exactly, but at present because earthing device impact characteristics testing apparatus is bulky, complicated operation, be difficult to transport and assembled in situ, and on-the-spot shock-testing belongs to high frequency, high pressure, high-current test, danger is also higher, so be badly in need of the lightning current generation device that development portablely can carry out the test of earthing device impact impedance, thus optimize the design of earthing device of power transmission line, ensure safe operation, reduce line upkeep cost tool to be of great significance.
Earthing device, under dash current effect, because of inductive effect and soil spark discharge effect, has transition feature, and the effective resistance value performance in each moment is inconsistent.The factors such as impulse earthed resistance and soil resistivity, amplitude of lightning current, grounding device constructions and physical dimension are relevant, are difficult to adopt single general expression to assess its performance.And power frequency earthing resistance is convenient to calculate and measure, in the design and assessment of electric power line pole tower earthing device, the value of stake resistance and measurement all simply adopt power frequency earthing resistance as design value and evaluation criteria.But the impact characteristics of shaft tower and power frequency characteristic have obvious difference, the impulse earthed resistance that earthing device presents under lightning current effect has different values from the stake resistance presented under power current effect, in practical operating experiences, also occurred that power frequency earthing resistance is less, but shaft tower is still subject to the situation of counterattack.The lumped parameter resistance of prior art employing particular value carrys out analogue ground device and carries out transmission line of electricity Lightning Protection Analysis, and it cannot be simulated really because of inductive effect and soil spark discharge effect, misses by a mile.
Utility model content
The purpose of this utility model is to provide a kind of portable lightning current generation device for the test of earthing device impact impedance, to solve the problems of the technologies described above.
To achieve these goals, the utility model adopts following technical scheme:
For the portable lightning current generation device of earthing device impact impedance test, comprise generator and the chamber of lightning current generator major loop; The major loop of lightning current generator major loop chamber, comprises isolating transformer T1, step-up transformer T2, rectification silicon stack D, charging resistor R1, divider, storage capacitor C, discharge switch S, adjustable wave regulating resistor R2 and adjustable harmonic inductance L; The input end of isolating transformer T1 connects the output terminal of generator, and the output terminal of isolating transformer T1 connects the input end of step-up transformer T2; Rectification silicon stack D, charging resistor R1 and divider are connected on the output terminal of step-up transformer T2; Storage capacitor C is in parallel with divider; Discharge switch S one end connects the positive pole of storage capacitor C, the other end connects one end of adjustable wave regulating resistor R2, the other end of adjustable wave regulating resistor R2 connects adjustable harmonic inductance L one end, and the other end of adjustable harmonic inductance L connects grounded screen to be measured by earthing test Current injection points; The surrounding of grounded screen to be measured is furnished with earthing test backflow pole; Earthing test backflow pole is connected to the negative pole of the storage capacitor C of lightning current generator major loop.
Preferably, earthing test backflow pole is arranged in from grounded screen distal end 2-3 rice distance to be measured circumferentially; 8-10 root earthing test backflow pole is circumferentially evenly arranged at this; The diameter of earthing test backflow pole is 2-3cm, and subterranean depth is identical with the grounded screen depth of burying, the reserved at least 30cm of aerial part; The resistance to flat type copper wire flowing to few 2kA in 8-10 root earthing test backflow pole connects, and one end of flat type copper wire is connected to the negative pole of the storage capacitor C of lightning current generator major loop.
Preferably, described portable lightning current generation device also comprises reference voltage pole and pulse analyser CH2.
Preferably, pulse analyser CH2 one end connects the other end of adjustable harmonic inductance L, and the other end connects reference voltage pole.
Preferably, reference voltage pole is arranged in from grounded screen distal end 10-15 rice; The diameter of reference voltage pole is 2-3cm, and subterranean depth is identical with the grounded screen depth of burying, the reserved at least 30cm of aerial part.
Preferably, the power of isolating transformer T1 is 3kW; The power of step-up transformer T2 is 3kW, and output voltage is 0 ~ 30kV; The resistance of charging resistor R1 is 1.1 × 10
6Ω; Storage capacitor C, capacitance is 0.6 μ F; The resistance of adjustable wave regulating resistor R2 is 13 Ω, and power is 300J; The inductance value of adjustable harmonic inductance L is 100 μ H, and power is 300J.
Preferably, storage capacitor C by two withstand voltage be 25kV, capacity be 0.3 μ F Capacitance parallel connection composition.
Preferably, discharge switch S can tolerate 30kV voltage, the sphere gap switch of switch off time within 8 μ S.
Preferably, the described portable lightning current generation device for the test of earthing device impact impedance also comprises test control box; Described test control box comprises test control panel; Test control panel is provided with liquid crystal touch screen, preset voltage table, charging voltage table, scram button, charging voltage knob and preset voltage knob; Charging voltage table is for showing the magnitude of voltage of the electricity in process of the test test major loop, storage capacitor C filled; Preset voltage table is used for the preset voltage values of display setting; Liquid crystal touch screen is used for carrying out test operation; Charging voltage knob is used for manual adjustments storage capacitor C charging voltage; Preset voltage knob is used for manual adjustments preset voltage; Discharge button and scram button are used for discharge switch S in Non-follow control major loop.
Preferably, the return wire that earthing test backflow pole connects storage capacitor C is provided with Luo-coil, and Luo-coil connects current oscilloscope by testing current line; Pulse analyser CH2 connects voltage oscilloscope by voltage tester line; Testing current line and voltage tester line are propped up on the ground with insulation strut by many, make these two wires keep the insulation distance of 50cm with ground; Insulation strut adopts epoxy resin to make, and length is 1m.
Portable lightning current generation device is adopted to carry out the method for earthing device impact impedance test, comprise the following steps: first, the high-voltage output end of lightning impulse generation device is connected to the Current injection points of grounded screen to be measured, the low-voltage output impacting generation device is connected to earthing test backflow pole; Then set preset charging voltage, discharging gap and discharge time, then turn-on voltage charges to storage capacitor C, and when charging voltage is greater than preset charging voltage, discharge switch S closes a floodgate and discharges, and electric discharge terminates, and completes a lightning impulse test; Discharge time subtracts 1, carries out time delay, again charging and discharging according to the time specified by inter-spike intervals, until off-test.
Preferably, gather High Voltage Impulse Waveform by pulse analyser CH2, gathered the impulse current waveform of earthing test backflow pole by Luo-coil; Impulse earthed resistance equals the peak value of peak value divided by dash current of surge voltage.
Relative to prior art, the utility model has following beneficial effect:
The utility model overcomes prior art and adopts the lumped parameter resistance of particular value to carry out the shortcoming that analogue ground device carries out transmission line of electricity Lightning Protection Analysis, a kind of portable lightning current generation device for the test of earthing device impact impedance is provided, this device can simulaed inductance effect and soil spark discharge effect really, tests out impulse earthed resistance really.This device it can realize in 25 Ω impedance loop situations, produce 8 μ s/20 μ s lightning current surge waveforms of 30kV voltage peak, 1kA current peak, can realize easy to carry, simple to operate with test safety, the impact impedance to earthing device that is accurately integrated carries out on-the-spot test, this can improve the work efficiency of earthing device impact impedance test greatly, especially for the earthing device in remote Gobi desert, mountain area.
Accompanying drawing explanation
Fig. 1 is the main circuit schematic diagram of portable lightning impulse generator;
Fig. 2 is test control panel schematic diagram;
Fig. 3 is optimum configurations interface schematic diagram;
Fig. 4 is test operation interface schematic diagram;
Fig. 5 is the experiment process figure of lightning impulse generation device.
Embodiment
Refer to shown in Fig. 1, a kind of portable lightning current generation device for the test of earthing device impact impedance of the utility model, comprises generator, the chamber of lightning current generator major loop, test control box, oscillograph, earthing test backflow pole, reference voltage pole and insulation strut.
1, generator provides power supply for whole lightning current generating means, and output power is 5kW, and output voltage is 0 ~ 220V, and this generator base uses the dielectric support that 30cm is high, and base material is epoxy resin.
2, refer to shown in Fig. 1, the major loop of lightning current generator major loop chamber, comprises isolating transformer T1, step-up transformer T2, rectification silicon stack D, charging resistor R1, divider, storage capacitor C, discharge switch S, adjustable wave regulating resistor R2, adjustable harmonic inductance L and pulse analyser.The input end of isolating transformer T1 connects the output terminal of generator, and the output terminal of isolating transformer T1 connects the input end of step-up transformer T2; Rectification silicon stack D, charging resistor R1 and divider are connected on the output terminal of step-up transformer T2; Storage capacitor C is in parallel with divider; Discharge switch S one end connects the positive pole of storage capacitor C, the other end connects one end of adjustable wave regulating resistor R2, the other end of adjustable wave regulating resistor R2 connects adjustable harmonic inductance L one end, and the other end of adjustable harmonic inductance L connects grounded screen to be measured by earthing test Current injection points.
Earthing test backflow pole is arranged in grounded screen surrounding to be measured: from grounded screen distal end 2-3 rice distance circumferentially.This circumferentially even squeeze in ground the earthing test of 8-10 root backflow pole (steel pole), the diameter of earthing test backflow pole is 2-3cm, the degree of depth squeezed in ground is identical with the grounded screen depth of burying, the reserved at least 30cm of earthing test backflow polar region upper part, with the resistance to flat type copper wire flowing to few 2kA, all earthing test backflow pole is connected, and one end of flat type copper wire is connected to the low-voltage output (negative pole of storage capacitor C) of lightning current generator major loop.Flat type copper wire is provided with Luo-coil CH1.
In the position from grounded screen distal end 10-15 rice, arrange a reference voltage pole, gather the reference point of voltage as oscillograph.The diameter of reference voltage pole is 2-3cm, and the degree of depth squeezed in ground is identical with the grounded screen depth of burying, the reserved at least 30cm of reference voltage polar region upper part.Pulse analyser CH2 one end connects the other end of adjustable harmonic inductance L, and the other end connects reference voltage pole.
(1) output terminal of generator is external in the power supply input of lightning current generator major loop, provides power supply for giving thunder major loop.
(2) isolating transformer T1, power is 3kW, isolates for the power supply of lightning current generator major loop and generator are supplied the power supply of miscellaneous equipment in this device.And the power supply of each low-voltage equipment such as oscillograph, control box is separated, to prevent from test process, due to earthy lifting, causing the damage of instrument.
(3) step-up transformer T2, power is 3kW, and output voltage is 0 ~ 30kV, for the voltage of major loop being increased to the magnitude of voltage of earthing device impulse test.
(4) rectification silicon stack D, for the AC power of input being inputted, rectification is direct current input.
(5) charging resistor R1, resistance is 1.1 × 10
6Ω, for controlling power supply to the time that storage capacitor C charges and charging current, making the duration of charging control at 10s, and charging current is controlled 4.99 × 10
-3a, thus namely ensure that and namely can not damage storage capacitor C too soon due to charging, in turn ensure that the duration of charging can not be too slow.
(6) be used in storage capacitor C charging process can the magnitude of voltage at Real-Time Monitoring storage capacitor C two ends for divider, and by this data transfer to test control box, and the LCDs be presented on control box, to be applied to the current pulse amplitude on ground connection rotary device in Control experiment.
(7) storage capacitor C, capacitance is 0.6 μ F, use two models to be MMJ25-0.3 in major loop withstand voltage be 25kV, capacity is that the Capacitance parallel connection of 0.3 μ F forms.This electric capacity is used for energy reserve, by the Co ntrolled release energy of switch S, thus makes output loop produce lightning surge.
(8) discharge switch S, use and can tolerate 30kV voltage, the sphere gap switch of switch off time within 8 μ S, for controlling the electric discharge of major loop storage capacitor C, its break-make is controlled by test control box, thus completes the discharging function of major loop.
(9) adjustable wave regulating resistor R2, resistance is 13 Ω, and power is 300J, and precision is 5%, for adjusting the lightning current waveform that major loop exports, makes waveform be 8 μ s/20 μ s lightning current surge waveforms of standard.
(10) adjustable harmonic inductance L, inductance value is 100 μ H, and power is 300J, and precision is 5%, for adjusting the lightning current waveform that major loop exports, makes waveform be 8 μ s/20 μ s lightning current surge waveforms of standard.
(11) grounded screen is the external test product of lightning current generator major loop, namely needs the earthing device testing ground connection impact impedance, between the high-voltage output end that need reliably be connected to lightning current generating loop and low-voltage output.
(12) pulse analyser withstand voltage is 30kV, and acquisition precision, within 1 μ S, realizes, to the extraction of tested earthing device both end voltage, being connected between Current injection points and ground reference.
(13) scale factor of Luo-coil is 100A/V, and the scale factor of pulse resistance voltage divider is 500:1, and the response time is less than 50ns, realizes the extraction to tested earthing device two ends electric current, is enclosed within backflow ground wire.
3, test control box comprises test control panel, controls remote control unit, liquid crystal touch screen and PLC, composition, for realizing the control exported device lightning current.
(1) testing control panel is the front panel of test control box, and it is arranged as shown in Figure 2.Test control panel is provided with liquid crystal touch screen, preset voltage table, charging voltage table, supply socket, AC 0 ~ 220 socket, controlling functions socket, scram button and voltage-regulation button.Voltage-regulation button comprises charging voltage knob and preset voltage knob.
Wherein, control remote control unit and on the touchscreen, can show preset voltage and charging voltage.In addition, test control box shows preset sparking voltage and charging voltage by numeral method, as shown in Fig. 2 upper right corner; Control box lower right corner knob is used for manual adjustments charging voltage and preset voltage; Right several second button of lower row is scram button, for there are special circumstances in test, uses when needing to stop rapidly; Lower row's controlling functions socket is used for joint test major loop, for controlling the break-make of major loop; AC 0 ~ 220 socket is used for the power supply of major loop chamber; Lower left corner socket is the power supply socket of test control box self.
1) charging voltage table: display charging voltage value, for showing the magnitude of voltage of the electricity in process of the test test major loop, storage capacitor C filled.
2) preset voltage table: the preset voltage values of display setting, for producing the voltage magnitude of impulse current waveform in Control experiment.
3) touch-screen: carry out test operation and guide ensureing proper operation.
4) charging voltage knob: connect T2, for manual adjustments storage capacitor C charging voltage.
5) preset voltage knob: for manual adjustments preset voltage.
6) discharge button: for discharge switch S in Non-follow control major loop, after pressing discharge button, major loop electric discharge produces lightning current wave.
7) scram button: for discharge switch S in Non-follow control major loop, after pressing this key, test unit is cutoff high immediately, discharges, then stops test.
(2) control remote control unit high pressure be logical for coordinating touch-screen and PLC to combine, preset voltage, charging voltage, electric discharge and sudden-stop function.
(3) liquid crystal touch screen is for touching the control operation realizing lightning current and export, and have following two interfaces, Fig. 3 is optimum configurations interface, and Fig. 4 is test operation interface.
As shown in Fig. 3 parameter setting interface, operator can set the time interval between the number of times of experiment, discharging gap, twice electric discharge, and the polarity of discharge current waveform, confirms to be provided with by clicking " determination " button.
More than dotted line being " test operation interface " in Fig. 4, is " remote control locking " button below dotted line.The charging of " high pressure leads to " realization to storage capacitor C in " test operation interface "; The charging complete of " height breaks " display to storage capacitor C; " high voltage rise " and " high pressure drop " realizes the adjustment to preset voltage and charging voltage, to adapt to the test needs of on-the-spot earthing device." electric discharge " button exports for the lightning current controlling thunder and lightning generation device." remote control locking " button realizes using a teleswitch and controls the switching locking press button that thunder and lightning generation device carries out optimum configurations and discharging function." manually or automatically " button is used for Selection experiment operation is manually discharge or programmed control automatic discharging.
(4) PLC is used for carrying out programmed control to process of the test, is illustrated in figure 5 the experiment process of lightning impulse generation device.First the high-voltage output end of lightning impulse generation device is connected to the Current injection points of grounded screen by on-test, the low-voltage output impacting generation device is connected to earthing test backflow pole, and then carrying out Selection experiment electric discharge at test operation interface by " automatic or manual " button is automatic or manual operation.
If selection automatic operation, then at optimum configurations interface and test control panel setting pre-arcing voltage, discharging gap and discharge time, then by " high pressure leads to " turn-on voltage, by setting " High voltage output ", the charging voltage value needed for trial voltage setting value is tested.Then according to programming, percussion mechanism starts automatically to charge to storage capacitor, when charging voltage is greater than preset charging voltage, percussion mechanism triggering discharges, experiment number subtracts 1, if test number (TN) is not equal to 0, then carry out time delay according to " inter-spike intervals " specified time, again charging and discharging, if experiment number equals 0, then off-test.
If selection manual operation, then connect high pressure by " high pressure leads to ", by setting " High voltage output ", the charging voltage value needed for trial voltage setting value is tested.Then by " height breaks ", disconnect high pressure, press " electric discharge " button, manually discharge, electric discharge terminates, then a lightning impulse test completes.
Oscillograph connection Luo-coil and pulse analyser are for showing test waveform, and voltage signal acquisition and current acquisition use two different oscillographs respectively, and use the isolating transformer do not passed through respectively.
The selection of earthing test Current injection points: for the grounded screen of shaft tower, selects the down conductor of grounded screen as decanting point; For the grounded screen (grounding net of transformer substation, electric field grounded screen etc.) beyond shaft tower class grounded screen, select in grounded screen emerging as decanting point.
Optical cable for connecting the major loop chamber of lightning current generator and test control box, for the transmission of discharge control signal.
Testing current line connects Luo-coil and oscillograph, for transmitting the current signal of collection.
Voltage tester line connects pulse analyser and oscillograph, for transmitting the current signal of collection.
The utility model adopts many insulation struts testing current line and voltage tester line to be propped up on the ground, makes these two wires keep the insulation distance of 50cm with ground.Insulation strut adopts epoxy resin to make, and length is 1m.
Claims (10)
1., for the portable lightning current generation device of earthing device impact impedance test, it is characterized in that, comprise generator and the chamber of lightning current generator major loop;
The major loop of lightning current generator major loop chamber, comprises isolating transformer T1, step-up transformer T2, rectification silicon stack D, charging resistor R1, divider, storage capacitor C, discharge switch S, adjustable wave regulating resistor R2 and adjustable harmonic inductance L; The input end of isolating transformer T1 connects the output terminal of generator, and the output terminal of isolating transformer T1 connects the input end of step-up transformer T2; Rectification silicon stack D, charging resistor R1 and divider are connected on the output terminal of step-up transformer T2; Storage capacitor C is in parallel with divider; Discharge switch S one end connects the positive pole of storage capacitor C, the other end connects one end of adjustable wave regulating resistor R2, the other end of adjustable wave regulating resistor R2 connects adjustable harmonic inductance L one end, and the other end of adjustable harmonic inductance L connects grounded screen to be measured by earthing test Current injection points; The surrounding of grounded screen to be measured is furnished with earthing test backflow pole; Earthing test backflow pole is connected to the negative pole of the storage capacitor C of lightning current generator major loop.
2. the portable lightning current generation device for the test of earthing device impact impedance according to claim 1, is characterized in that, earthing test backflow pole is arranged in from grounded screen distal end 2-3 rice distance to be measured circumferentially; 8-10 root earthing test backflow pole is circumferentially evenly arranged at this; The diameter of earthing test backflow pole is 2-3cm, and subterranean depth is identical with the grounded screen depth of burying, the reserved at least 30cm of aerial part; The resistance to flat type copper wire flowing to few 2kA in 8-10 root earthing test backflow pole connects, and one end of flat type copper wire is connected to the negative pole of the storage capacitor C of lightning current generator major loop.
3. the portable lightning current generation device for the test of earthing device impact impedance according to claim 1, it is characterized in that, described portable lightning current generation device also comprises reference voltage pole and pulse analyser CH2.
4. the portable lightning current generation device for the test of earthing device impact impedance according to claim 3, it is characterized in that, pulse analyser CH2 one end connects the other end of adjustable harmonic inductance L, and the other end connects reference voltage pole.
5. the portable lightning current generation device for the test of earthing device impact impedance according to claim 3, it is characterized in that, reference voltage pole is arranged in from grounded screen distal end 10-15 rice; The diameter of reference voltage pole is 2-3cm, and subterranean depth is identical with the grounded screen depth of burying, the reserved at least 30cm of aerial part.
6. the portable lightning current generation device for the test of earthing device impact impedance according to claim 1, it is characterized in that, the power of isolating transformer T1 is 3kW; The power of step-up transformer T2 is 3kW, and output voltage is 0 ~ 30kV; The resistance of charging resistor R1 is 1.1 × 10
6Ω; Storage capacitor C, capacitance is 0.6 μ F; The resistance of adjustable wave regulating resistor R2 is 13 Ω, and power is 300J; The inductance value of adjustable harmonic inductance L is 100 μ H, and power is 300J.
7. according to claim 1 for earthing device impact impedance test portable lightning current generation device, it is characterized in that, storage capacitor C by two withstand voltage be 25kV, capacity be 0.3 μ F Capacitance parallel connection form.
8. the portable lightning current generation device for the test of earthing device impact impedance according to claim 1, it is characterized in that, discharge switch S can tolerate 30kV voltage, the sphere gap switch of switch off time within 8 μ S.
9. the portable lightning current generation device for the test of earthing device impact impedance according to claim 1, is characterized in that, the described portable lightning current generation device for the test of earthing device impact impedance also comprises test control box; Described test control box comprises test control panel; Test control panel is provided with liquid crystal touch screen, preset voltage table, charging voltage table, scram button, charging voltage knob and preset voltage knob; Charging voltage table is for showing the magnitude of voltage of the electricity in process of the test test major loop, storage capacitor C filled; Preset voltage table is used for the preset voltage values of display setting; Liquid crystal touch screen is used for carrying out test operation; Charging voltage knob is used for manual adjustments storage capacitor C charging voltage; Preset voltage knob is used for manual adjustments preset voltage; Discharge button and scram button are used for discharge switch S in Non-follow control major loop.
10. the portable lightning current generation device for the test of earthing device impact impedance according to claim 4, it is characterized in that, the return wire that earthing test backflow pole connects storage capacitor C is provided with Luo-coil, and Luo-coil connects current oscilloscope by testing current line; Pulse analyser CH2 connects voltage oscilloscope by voltage tester line; Testing current line and voltage tester line are propped up on the ground with insulation strut by many, make these two wires keep the insulation distance of 50cm with ground; Insulation strut adopts epoxy resin to make, and length is 1m.
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Inventor after: Wang Sen Inventor after: Yao Xueling Inventor after: Lei Wanglong Inventor after: Cheng Lin Inventor after: Li Zhizhong Inventor after: Xue Jun Inventor after: Chen Jingliang Inventor after: Geng Bo Inventor after: Ji Hongliang Inventor after: Wang Jing Inventor after: Niu Bo Inventor before: Wang Sen Inventor before: Lei Wanglong Inventor before: Cheng Lin Inventor before: Li Zhizhong Inventor before: Chen Jingliang Inventor before: Geng Bo Inventor before: Ji Hongliang Inventor before: Wang Jing Inventor before: Niu Bo Inventor before: Yao Xueling |
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