CN202975161U - Device for automatically measuring impedance of grounding grid - Google Patents
Device for automatically measuring impedance of grounding grid Download PDFInfo
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- CN202975161U CN202975161U CN 201220663731 CN201220663731U CN202975161U CN 202975161 U CN202975161 U CN 202975161U CN 201220663731 CN201220663731 CN 201220663731 CN 201220663731 U CN201220663731 U CN 201220663731U CN 202975161 U CN202975161 U CN 202975161U
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Abstract
The utility model discloses a device for automatically measuring impedance of a grounding grid. The device comprises a housing an electronic line, wherein the electronic line is that test current generated by a 45 HZ/55 Hz pilot frequency constant current source is output through test output ends C1 and C2 on a panel; a current amplification circuit, through a current mutual inductor, obtains and amplifies the test current output by the 45 HZ/55 Hz pilot frequency constant current source and then is connected with a measuring switching and computing circuit; a voltage amplification circuit amplifies voltage obtained across measuring voltage input ends P1 and P2 on the panel and then is connected with the measuring switching and computing circuit; the measuring switching and computing circuit is connected with a filter circuit; the filter circuit is connected with an A/D conversion circuit and a micro-computer system; and the A/D conversion circuit and the micro-computer system are connected with a display, a printer and an RS 232 interface as well as a USB communication interface. The device uses two frequencies, 45 Hz and 55 Hz, for measuring, and thus the device is high in accuracy and equivalence of measurement, is strong in anti-ground voltage interference capability and high in precision.
Description
Technical field
The utility model belongs to the electronic test equipment technical field, especially relates to a kind of automatic measurement grounded screen impedance means.
Background technology
The test job of present domestic earthing device is weaker, and some crucial Technologies And Conceptions are fuzzyyer, and technological means falls behind; When earthing device is measured, owing to being subjected to the various interference such as uneven zero-sequence current and radio frequency, make the impedance ground of test result generation very large error, particularly large-scale grounding network generally very little, generally below 0.5 Ω, disturb the relative error of bringing larger; In order to reduce the on-the-spot impact of disturbing, the method that adopts at present mainly contains two kinds, a kind of is to increase measuring current, a kind of is to use the alien frequencies method, first method is to strengthen signal voltage and marking current by strengthening measuring current, thereby raising signal to noise ratio (S/N ratio), reduce measuring error, this method makes equipment very heavy owing to having adopted very large measuring current (DL/T475-2006 standard recommendation should not less than 50A), and wiring labour intensity is very large, take time and effort, and, disturb and the same frequency of signal due to main, can't fundamentally eliminate the impact of interference; The alien frequencies rule is to avoid power frequency by the frequency that changes measuring current to disturb, because signal frequency is different from interfering frequency, just can come by wave filter the impact of filtering interfering, thereby raising measuring accuracy, the alien frequencies method is because the measuring current that adopts is less, so equipment is small and exquisite, and wiring labour intensity also alleviates greatly, have advantages of that test result is reliable and stable and time saving and energy saving, the test of alien frequencies method is accepted extensively and is adopted by domestic and international expert.
But according to definition, the power-frequency earthing impedance refers to the impedance that earthing device presents under power current, and the measuring current frequency that the alien frequencies method adopts is not power frequency, therefore the numerical value that records will have deviation with the value that records under power current, theory and practice shows, the reason that produces deviation is that the impedance ground of earthing device is complex impedance, not only comprise the resistance component, also contain the inductive relevant with frequency and capacitive component; The test frequency that adopts and power frequency differ and heal that far equivalence is poorer, and namely measuring error is larger.For the accuracy that guarantees to test, test frequency and power frequency can not be too wide in the gap, and the waveform of measuring current should be sinusoidal wave (other waveforms such as square wave contain abundant harmonic frequency); As far back as the seventies, the state such as the U.S., Japan has just stipulated that the difference of test frequency and power frequency can not surpass 10Hz, CNS GB/T17949.1-2000 requirement measuring current frequency should be as far as possible near power frequency, and industry standard DL/T475-2006 has stipulated that the measuring current frequency should be between 40～60Hz.
Summary of the invention
The purpose of this utility model is advanced height, anti-ground voltage interference performance is strong, precision is high automatic measurement grounded screen impedance means at the accuracy that provides a kind of 45Hz of employing and two kinds of frequencies of 55Hz to measure, measure with the deficiency of improving prior art and equivalence.
The purpose of this utility model is to realize like this, a kind of automatic measurement grounded screen impedance means, formed by housing and electronic circuit, its characteristics be electronic circuit be the measuring current that produces of 45Hz/55Hz alien frequencies constant-current source circuit by test output terminal C1, C2 on panel output, connect to measure after the measuring current that current amplification circuit is obtained the output of 45Hz/55Hz alien frequencies constant-current source circuit by current transformer is amplified and switch and computing circuit; Connect to measure after the voltage amplification of voltage amplifier circuit with measuring voltage input end P1, P2 acquisition on panel and switch and computing circuit; Measure switching and connect filtering circuit with computing circuit, filtering circuit connects A/D change-over circuit and microcomputer system, and the A/D change-over circuit is connected display and printer and RS232, USB communication interface with microcomputer system.
described 45Hz/55Hz alien frequencies constant-current source circuit is: 1 pin of four path analoging switch IC1 connects 6 pin of current amplification circuit operational amplifier A 4, and 4 pin of four path analoging switch IC1 connect 6 pin of current amplification circuit operational amplifier A 3,2 of four path analoging switch IC1, connect after 3 pin short circuits to measure and switch and 5 of computing circuit resistance R 62, four path analoging switch IC1, connect 1 pin of the NPN Darlington transistor IC2 of built-in fly-wheel diode after 6 pin short circuits, 7 pin of four path analoging switch IC1 connect negative supply, and 8 pin series resistor R33 connect 6 pin of dual operational amplifier A5, the parallel connected end of resistance R 32, resistance R 32 meet 7 pin of dual operational amplifier A5,9 of four path analoging switch IC1, after 10 pin short circuits, series resistor R17 connects 3 pin of dual operational amplifier A5, the 11 pin connecting resistance R30 of four path analoging switch IC1, but the parallel connected end that the end of adjustable resistance RP1 is connected with the adjustable side, another termination of resistance R 30 is measured the resistance R 63 in switching and computing circuit 4, the parallel connected end of 8 pin of relay J 1 connects the resistance R 27 of measuring in switching and computing circuit 4 after the other end series resistor R3 of adjustable resistance RP1, diode D15 negative pole, capacitor C 14, resistance R 85, resistance R 95, the parallel connected end of resistance R 39,12 of four path analoging switch IC1, connect after 13 pin short circuits built-in fly-wheel diode NPN Darlington transistor IC2 2, 5 pin, the 14 pin series resistor R18 of four path analoging switch IC1, No. 5 of junction plate key lead-in wires after R40, 1 pin of dual operational amplifier A5 meets triode T11, the base stage of T12, the collector of triode T11 connects 3 pin of filtering circuit 5 operational amplifier A 9, the emitter of triode T12 meets filtering circuit 5 telefault U2, capacitor C 6 negative poles, resistance R 100, 3 pin of operational amplifier A 10, the parallel connected end of resistance R 5, the collector of triode T12, the emitter of triode T11 connects measures the resistance R 47 of switching with computing circuit 4, capacitor C 28, connect 2 pin of dual operational amplifier A5 after the parallel connected end of A/D change-over circuit and microcomputer system 6 and series resistor R10, 4 pin of dual operational amplifier A5 connect negative supply, 5 pin series resistor R34 connect the resistance R 61 of measuring in switching and computing circuit 4, capacitor C 42, the resistance R 76 of current amplification circuit 2, capacitor C 39, resistance R 4, resistance R 70, the parallel connected end of measuring current output terminal C2, No. 5 lead-in wires of junction plate key after the 8 pin serial connection R40 of dual operational amplifier A5, 3, the 13 pin skies of the NPN Darlington transistor IC2 of built-in fly-wheel diode connect, 9,12 pin short circuits, 8,10 pin connect respectively negative supply, No. 5 of junction plate key lead-in wires after 14 pin series resistor R40, series resistor R99, light emitting diode LD5 are anodal, light emitting diode LD5 negative pole connects negative supply, 11 pin connect 10 pin of four nor gate IC4, connect No. 4 lead-in wires of negative supply, panel key after 4,6, the 7 pin short circuits of the NPN Darlington transistor IC2 of built-in fly-wheel diode, 1 of integrated pulse width modulation device IC3, 3, 16 pin skies connect, and 4, 5, 8, connect negative supply after 10 pin short circuits, the 2 pin connecting resistance R28 of integrated pulse width modulation device IC3 and capacitor C 13 parallel connected end, series resistor R27 connects to measure and switches and computing circuit 4 diode D15 negative poles, capacitor C 14, resistance R 31, resistance R 85, resistance R 39, the parallel connected end of resistance R 95, resistance R 28, connect negative supply after the other end parallel connection of capacitor C 13, the 6 pin series resistor R24 of integrated pulse width modulation device IC3,7 pin serial connection capacitor C 12,9 pin serial connection R23, connect negative supply after capacitor C 11,11 pin of integrated pulse width modulation device IC3 connect triode T6 base stage, the parallel connected end of resistance R 22, another termination negative supply of R22,14 pin of integrated pulse width modulation device IC3 connect triode T5 base stage, the parallel connected end of resistance R 21, another termination negative supply of resistance R 21,12 of integrated pulse width modulation device IC3, series resistor R25 after 13 pin short circuits, No. 5 of series resistor R40 junction plate key lead-in wires after the other end of resistance R 25 and 15 pin short circuits, triode T6, the collector of T5 connects respectively the two ends of transformer T power supply input winding, and the center tap of transformer T input winding connects+the 9V power supply, and the output winding two ends of transformer T connect respectively by diode D7, D8, D9, the input end of the bridge rectifier circuit that D10 forms, diode D7, D8, D9, the telefault U1 of the positive output termination filtering circuit 5 of the bridge rectifier circuit that D10 forms, capacitor C 7 positive poles, the parallel connected end of resistance R 19, the telefault U2 of negative output termination filtering circuit 5, the parallel connected end of capacitor C 8 negative poles, 3,4,9, the 11 pin skies of four nor gate IC4 connect, 1, No. 5 of series resistor R40 junction plate key lead-in wires after 2,12,13,14 pin short circuits, four nor gate 7 pin connect negative supply, 5, the end of connecting resistance R52 after 6 pin short circuits, the end of 8 pin serial connection adjustable resistance RP7 connecting resistance R53,10 pin, the serial connection capacitor C 10 that the other end parallel connection of resistance R 52, R53 is connected in series capacitor C 22 access four nor gate IC4 afterwards connect negative supply, connect 11 pin of the NPN Darlington transistor IC2 of built-in fly-wheel diode, connect the emitter of triode T9, the resistance R 51 of filtering circuit 5 after the base stage series resistor R41 of triode T7, the emitter of triode T7 connects the collector of triode T9, the collector of triode T7 connects the parallel connected end of measure switching with 2 pin of the resistance R OUT of computing circuit 4, relay J 4, the base stage of triode T9 connects the parallel connected end of capacitor C 4, diode D6 negative pole, D5 is anodal for the anodal serial connection of diode D6 voltage stabilizing diode, and the negative pole of voltage stabilizing diode D5 connects the emitter of the triode T8 that measures current output terminal C1, filtering circuit 5.
described current amplification circuit 2 is: 5 pin skies of operational amplifier A 4 connect, 1 pin series resistor R66, adjustable resistance RP5, resistance R 68 connects 8 pin, 7 pin of the adjusting termination operational amplifier A 4 of adjustable resistance RP5, 7 pin of operational amplifier A 3, 2 pin connecting resistance R67 of operational amplifier A 4, the parallel connected end of resistance R 69, 6 pin of another termination operational amplifier A 4 of resistance R 67, 2 pin of another termination operational amplifier A 3 of resistance R 69, connecting resistance R76 after 3 pin series resistor R4 of operational amplifier A 4, capacitor C 39, measuring current output terminal C2, resistance R 70, measure the resistance R 61 of switching with computing circuit 4, capacitor C 42, resistance R 34 parallel connected end of 45Hz/55Hz alien frequencies constant-current source circuit 1, contact between the other end connecting resistance R77 serial connection R78 of capacitor C 39, another termination capacitor C 37 of resistance R 76, C38 parallel connected end, the other end connecting resistance R77 of capacitor C 38,5 pin of dual operational amplifier A2 connect the parallel connected end of 7,8 pin of dual operational amplifier A1 of the other end, the voltage amplifier circuit 3 of capacitor C 37 after the other end series resistor R78 of resistance R 77, 6 pin of operational amplifier A 4 connect 1 pin of four path analoging switch IC1 of 45Hz/55Hz alien frequencies constant-current source circuit 1, and 4 pin of operational amplifier A 4 connect negative supply, 1,5,8 pin skies of operational amplifier A 3 connect, 2 pin connecting resistance R69, and 3 pin connect the parallel connected end of adjustable resistance RP6, resistance R 71, but the other end of adjustable resistance RP6 and adjustable side series resistor R70 thereof meet measuring current output terminal C2, the other end serial connection capacitor C 31 of resistance R 71 connects 6,7 pin of dual operational amplifier A2, 4 pin of operational amplifier A 3 connect negative supply, 6 pin connect 4 pin, the resistance R 72 of four path analoging switch IC1 of 45Hz/55Hz alien frequencies constant-current source circuit 1, the parallel connected end of capacitor C 29, connect 1,2 pin of dual operational amplifier A2 after the other end parallel connection of resistance R 72, capacitor C 29 after series resistor R73, capacitor C 30, connect capacitor C 30 after 1, the 2 pin short circuits of dual operational amplifier A2,3 pin connect the resistance R 74 of voltage amplifier circuit 3, the parallel connected end of capacitor C 36,4 pin connect negative supply, 5 pin connect the contact between capacitor C 38 series resistor R77,6, connect the parallel connected end of the voltage stabilizing diode D21 positive pole of 8 pin that capacitor C 31,8 pin meet dual operational amplifier A1, filtering circuit 5 after 7 pin short circuits.
described voltage amplifier circuit 3 is: 5 pin skies of operational amplifier A 6 connect, 1 pin series resistor R49, adjustable resistance RP10, resistance R 3 connects 8 pin, connect the contact between the filtering circuit 5 anodal serial connection capacitor C of capacitor C 87 negative poles after 2 pin series resistor R91 of operational amplifier A 6, capacitor C 4, capacitor C 1, measure the resistance R 89 of switching with computing circuit 4, the parallel connected end of 3 pin of relay J 4, meet measuring voltage input end P2 after 3 pin series resistor R92 of operational amplifier A 6, resistance R 79 parallel connected end, 5 pin of another termination dual operational amplifier A1 of resistance R 79, 4 pin of operational amplifier A 6 connect negative supply, it is anodal that 6 pin meet diode D13, the parallel connected end of diode D20 negative pole, the anodal serial connection of diode D20 capacitor C 32 positive poles, capacitor C 32 negative poles connect negative supply, connect after diode D13 negative pole series resistor R90 and measure the resistance R 89 of switching with computing circuit 4, the parallel connected end of adjustable resistance RP9, 7 pin connect the adjustable side of adjustable resistance RP10, No. 5 lead-in wires of junction plate key after serial connection R40, 1 of dual operational amplifier A1, contact after 2 pin short circuits between connecting resistance R75 serial connection capacitor C 35, the other end connecting resistance R74 of resistance R 75, the parallel connected end of capacitor C 34, 3 pin of another termination dual operational amplifier A2 of resistance R 74, the parallel connected end of capacitor C 36, the other end connecting resistance R65 of capacitor C 36, the parallel connected end of the other end of capacitor C 35, another termination capacitor C 34 of resistance R 65, contact between the other end connecting resistance R75 series resistor R74 of capacitor C 34, 3 pin of dual operational amplifier A1 meet measuring voltage input end P1, the parallel connected end of resistance R 50, another termination of resistance R 50 is measured 5 pin that switch with computing circuit 4 four high guaily unit IC5, the parallel connected end of resistance R 86, 4 pin of dual operational amplifier A1 connect negative supply, 6, connect current amplification circuit 2 resistance R 78 after 7 pin short circuits, the parallel connected end of capacitor C 37, 8 pin of 8 pin and dual operational amplifier A2 and to connect filtering circuit 5 voltage stabilizing diode D21 anodal.
described measurement switching and computing circuit 4 are: 5 pin skies of operational amplifier A 7 connect, 1 pin series resistor R59, adjustable resistance RP4, resistance R 60 connects 8 pin, 2 pin connecting resistance R63, capacitor C 40, the parallel connected end of resistance R 64,1 pin of another relay termination J1 of resistance R 63, the resistance R 30 of 45Hz/55Hz alien frequencies constant-current source circuit 1, resistance R 64, 6 pin of another termination operational amplifier A 7 of capacitor C 40 parallel connections, but an end and the adjustable side thereof of adjustable resistance RP8, the parallel connected end of resistance R 58,2 pin of another relay termination J1 of resistance R 58, the parallel connected end of resistance R 61, another termination capacitor C 42 of resistance R 61, the resistance R 34 of 45Hz/55Hz alien frequencies constant-current source circuit 1, measuring current output terminal C2, the resistance R 70 of current amplification circuit 2, resistance R 76, resistance R 4, the parallel connected end of capacitor C 39,3 pin of another relay termination J1 of adjustable resistance RP8,3 pin connecting resistance R62 of operational amplifier A 7, the parallel connected end of capacitor C 27,2 of four path analoging switch IC1 of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of resistance R 62, 3 pin, 4 pin of another termination operational amplifier A 7 of capacitor C 27,4 pin of operational amplifier A 7 connect negative supply, but 7 pin of operational amplifier A 7 connect the adjustable side of adjustable resistance RP4, 7 pin of operational amplifier A 8 etc. are connected in series No. 5 lead-in wires of junction plate key after R40 together, 5 pin skies of operational amplifier A 8 connect, 1 pin series resistor R55, adjustable resistance RP3, resistance R 56 connects 8 pin, 2 pin connecting resistance R57, the parallel connected end of capacitor C 41, the other end connecting resistance R46 of resistance R 57, capacitor C 28, the parallel connected end of resistance R 54, resistance R 54, the other end of capacitor C 41 also connects 6 pin of operational amplifier A 8, the end of resistance R OUT, the collector of the triode T7 of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of resistance R OUT, 2 pin of relay J 4, 1 pin of another relay termination J1 of resistance R 46, connect A/D change-over circuit and microcomputer system 6 after 3 pin series resistor R47 of operational amplifier A 8, the other end of capacitor C 28, the emitter of the triode T11 of 45Hz/55Hz alien frequencies constant-current source circuit 1, the collector of triode T12, the parallel connected end of resistance R 10, 4 pin of operational amplifier A 8 connect negative supply, but 7 pin connect the adjustable side of adjustable resistance RP3, No. 5 lead-in wires of junction plate key after serial connection R40, 1 pin of four high guaily unit IC5 connects 4 pin of the operational amplifier A 9 of filtering circuit 5, 7 pin of operational amplifier A 10 connect 10 pin after the 2 pin series resistor R38 of four high guaily unit IC5, and 10 pin series resistor R37 connect 8 pin, and it is anodal that 8 pin meet diode D17, and diode D17 negative pole connects 6 pin of four XOR gate IC6, series resistor R48 connects 7 pin of four XOR gate IC6, capacitor C 20 positive poles, the parallel connected end of resistance R 45, the 3 pin connecting resistance R85 of four high guaily unit IC5, the parallel connected end of R84, the other end connecting resistance R27 of resistance R 85, capacitor C 14, the parallel connected end of diode D15, contact between resistance R 95 serial connection R39, another termination negative supply of resistance R 84,4 of four high guaily unit IC5, serial connection capacitor C 24 between 11 pin, No. 5 lead-in wires of junction plate key after the 4 pin serial connection R40 of four high guaily unit IC5, resistance R 15, the parallel connected end of resistance R 14,13 pin of another termination four XOR gate IC6 of resistance R 15, series resistor R12 succeeds 1 pin of electrical equipment J2,1 pin of another termination four XOR gate IC6 of resistance R 14, succeed 7 pin of electrical equipment J1 after series resistor R11, the 5 pin connecting resistance R50 of four high guaily unit IC5, the parallel connected end of resistance R 86, another termination measuring voltage input end P1 of resistance R 50,6 pin of another relay termination J4 of resistance R 86, the 6 pin series resistor R87 of four high guaily unit IC5 connect 7 pin, the end of 7 pin connecting resistance R88, but connect the resistance R 90 of voltage amplifier 3 behind the other end of resistance R 88 serial connection adjustable resistance RP9 and adjustable side thereof, succeed 3 pin of electrical equipment J4 after the other end series resistor R89 of adjustable resistance RP9, contact between the anodal serial connection capacitor C of capacitor C 87 negative poles of filtering circuit 5, capacitor C 4, capacitor C 1, the parallel connected end of the resistance R 91 of voltage amplifier 3, the 9 pin connecting resistance R35 of four high guaily unit IC5, be connected in series No. 5 lead-in wires of junction plate key after R40 together with the parallel connected end of R36,7 pin of the other end of resistance R 35 and operational amplifier A 8 etc., another termination negative supply of resistance R 36, the 12 pin connecting resistance R19 of four high guaily unit IC5, the parallel connected end of resistance R 20, capacitor C 7 positive poles of another termination filtering circuit 5 of resistance R 19, telefault U1, by diode D7, D8, D9, the positive output end of the bridge rectifier that D10 forms, another termination negative supply of resistance R 20,13 of four high guaily unit IC5, 14 pin short circuits, the 4 pin skies of four XOR gate IC6 connect, 1 pin connecting resistance R14, the parallel connected end of resistance R 11, the other end connecting resistance R15 of resistance R 14, No. 5 lead-in wires of junction plate key after serial connection R40,7 pin of another relay termination J1 of resistance R 11,2 of four XOR gate IC6, 5, 9, meet 3 of A/D change-over circuit and microcomputer system 6, four XOR gate IC6 after 12 pin short circuits, 10, 11 pin connect respectively 28 of display 7, 36, 32 pin, the 6 pin connecting resistance R48 of four XOR gate IC6, the parallel connected end of diode D17 negative pole, 7 pin of another termination four XOR gate IC6 of resistance R 48, capacitor C 20 positive poles, resistance R 45, the parallel connected end of A/D change-over circuit and microcomputer system 6,1 pin of another relay termination J4 of resistance R 45, the negative pole of capacitor C 20 connects negative supply, the 8 pin connecting resistance R16 of four XOR gate IC6, the parallel connected end of R13,1 pin of another relay termination J3 of resistance R 13,2 pin of another termination JK1 of resistance R 16, C3 is anodal, the parallel connected end of A/D change-over circuit and microcomputer system 6, the 13 pin connecting resistance R15 of four XOR gate IC6, the parallel connected end of resistance R 12, No. 5 of junction plate key lead-in wires after the other end connecting resistance R14 series resistor R40 of resistance R 15,1 pin of another relay termination J2 of resistance R 12, the 14 pin connecting resistance R9 of four XOR gate IC6, resistance R 39, the parallel connected end of capacitor C 33,16 pin of the trigger IC7 of another termination filtering circuit 5 of resistance R 9, the capacitor C 9 of 45Hz/55Hz alien frequencies constant-current source circuit 1, the parallel connected end of the pin of connection terminal JK1, the other end connecting resistance R85 of resistance R 39, the capacitor C 14 of 45Hz/55Hz alien frequencies constant-current circuit 1, diode D15 negative pole, resistance R 27, resistance R 31, the parallel connected end of resistance R 95, the other end serial connection adjustable resistance RP2 of resistance R 95, connect the anodal contact that is connected in series between capacitor C 5 negative poles of capacitor C 6 of filtering circuit 5 after resistance R 96, the regulated termination A/D change-over circuit of adjustable resistance RP2 and microcomputer system 6.
described filtering circuit 7 is: 1 of trigger IC7, 12, 15 pin skies connect, 2 pin connecting resistance R83, the parallel connected end of light emitting diode LD1 positive pole, 5 pin connecting resistance R82, the parallel connected end of light emitting diode LD2 positive pole, 7 pin connecting resistance R81, the parallel connected end of light emitting diode LD3 positive pole, 10 pin connecting resistance R80, the parallel connected end of light emitting diode LD4 positive pole, light emitting diode LD1, LD2, LD3, after the negative pole parallel connection of LD4, series resistor R26 connects negative supply, resistance R 80, R81, R82, the other end of R83 meets respectively triode T1, T2, T3, the base stage of T4, the coil of the collector connecting relay J1 of triode T1, the parallel connected end of diode D19 positive pole, the coil of the collector connecting relay J2 of triode T2, the parallel connected end of diode D18 positive pole, the coil of the collector connecting relay J3 of triode T3, the parallel connected end of diode D16 positive pole, the coil of the collector connecting relay J4 of triode T4, the parallel connected end of diode D14 positive pole, relay J 1, J2, J3, the other end of J4 coil and diode D19, D18, D16, meet+the 9V power supply 3 of trigger IC7 after the negative pole parallel connection of D14, 4, 6, 11 pin are series diode D1 respectively, D2, D11, D12 is anodal, diode D1, D2, D11, 9 pin of contact hair device IC7 after the negative pole short circuit of D12,8 of trigger IC7, 13, meet triode T1 after 14 pin short circuits, T2, T3, the parallel connected end of T4 emitter, negative supply, resistance R 97, R98, R93, parallel end connection capacitor C 3 negative poles of R94, capacitor C 3 positive poles connect 2 pin of connection terminal JK1, measure the resistance R 16 of switching with computing circuit 4, the parallel connected end of A/D change-over circuit and microcomputer system 6, resistance R 97, R98, R93, 6 of the other end difference junction plate key of R94, 7, 8, No. 9 lead-in wires, 16 pin of trigger IC7 connect to measure and switch and computing circuit 4 resistance R 9, the parallel connected end of capacitor C 9, 3 pin of connection terminal JK1, 1,5,8 pin skies of operational amplifier A 10 connect, and 2 pin connect the collector of triode T8, and 3 pin of operational amplifier A 10 connect the parallel connected end of contact between telefault U2 serial connection capacitor C 6 negative poles of filtering circuit 5, resistance R 5, resistance R 100, another termination voltage stabilizing diode D3 of resistance R 5 is anodal, the parallel connected end of D4 negative pole, one termination negative supply of the negative pole of voltage stabilizing diode D3 and resistance R 51, 4 pin of another termination operational amplifier A 10 of resistance R 100, the parallel connected end of the positive pole of voltage stabilizing diode D4, 6 pin of operational amplifier A 10 connect the base stage of triode T8, the emitter of triode T8 meets measuring current output terminal C1, the negative pole of the voltage stabilizing diode D5 of 45Hz/55Hz alien frequencies constant-current source circuit 1, 7 pin of operational amplifier A 10 connect 4 pin of operational amplifier A 9, measure 1 pin of the four high guaily unit IC5 of switching and computing circuit 4, 1 of operational amplifier A 9, 5, 8 pin skies connect, and 2 pin connect triode T10 collector, the parallel connected end of resistance R 1, the parallel end connection voltage stabilizing diode D21 negative pole of the other end of resistance R 1 and resistance R 2, the parallel connected end of voltage stabilizing diode D22 positive pole, the positive pole of voltage stabilizing diode D21 connect 8 pin of the dual operational amplifier A1 of voltage amplifier circuit 3, 8 pin of the dual operational amplifier A2 of current amplification circuit 2, after the other end series resistor R6 of resistance R 2 with 7 pin of operational amplifier A 9, the negative pole of voltage stabilizing diode D22 meets telefault U1 together, the parallel connected end of capacitor C 5 positive poles, the diode D7 of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of telefault U1, D8, D9, the positive output end of the bridge rectifier that D10 forms, the positive pole of capacitor C 7, measure the parallel connected end of the resistance R 19 in switching and computing circuit 4, the negative pole of capacitor C 5 connects the positive pole of capacitor C 6, measure the parallel connected end of the resistance R 96 of switching and computing circuit 4, the negative pole of capacitor C 6 meets telefault U2, 3 pin of the operational amplifier A 10 of 45Hz/55Hz alien frequencies constant-current source circuit 1, resistance R 100, the parallel connected end of resistance R 5, the negative pole of another termination capacitor C 8 of telefault U2, the diode D7 of 45Hz/55Hz alien frequencies constant-current circuit 1, D8, D9, the negative output terminal of the bridge rectifier that D10 forms, the positive pole of capacitor C 8 connects capacitor C 7 negative poles, capacitor C 4, the parallel connected end of capacitor C 1 grade, 3 pin of operational amplifier A 9 connect the collector of the triode T11 of 45Hz/55Hz alien frequencies constant-current source circuit 1,6 pin of operational amplifier A 9 connect the base stage of triode T10 and the parallel connected end of capacitor C 2, the emitter of triode T10 connects serial connection capacitor C 1 after the other end of capacitor C 2, the other end serial connection capacitor C 4 of capacitor C 1, contact between capacitor C 7 negative pole serial connection C8 positive poles, the resistance R 91 of voltage amplifier circuit 3, measure the resistance R 89 of switching with computing circuit 4, the parallel connected end of 3 pin of relay J 4, the triode T9 base stage of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of capacitor C 4 and the parallel connected end of diode D6 negative pole, capacitor C 7 positive poles meet telefault U1, diode D7, D8, D9, the positive output end of the bridge rectifier that D10 forms, measure the parallel connected end of the resistance R 19 of switching and computing circuit 4.
the utility model is mainly that the electric current that 45Hz/55Hz alien frequencies constant-current source circuit produces passes through output terminal C1, C2 output, the electric current that current amplifier circuit is obtained the output of 45Hz/55Hz alien frequencies constant-current source circuit by current transformer amplifies, flow to the filtering circuit for filtering interference signals, filtering circuit connects the A/D change-over circuit, voltage amplifier circuit is with voltage input end P1, the voltage amplification that P2 obtains, flow to the filtering circuit for filtering interference signals, filtering circuit connects the A/D change-over circuit, the A/D change-over circuit connects microcomputer system, microcomputer system connects display and printer, recently measure impedance ground by the potential rise of measuring earthing device and the electric current that flows into earthing device, adopt 45Hz and two kinds of frequencies of 55Hz to measure, calculate again equiva lent impedance under 50Hz by software for calculation, therefore accuracy and the equivalence measured are further enhanced,
The utility model is applicable to test power frequency characterisitic parameter and the soil impedance rates such as the power-frequency earthing impedance, touch voltage, step voltage, transfer current potential, place surface potential gradient of all kinds of earthing device.Adopt the alien frequencies Anti-Jamming Technique, can accurately record the data under power frequency 50Hz under strong interference environment, measuring current is less, maximum 5A, in the time of can not causing test, the current potential of earthing device is not too high, have extremely strong antijamming capability, can be under transformer station's strong interference environment Measurement accuracy, therefore can be in the situation that do not have a power failure and measure.Measurement result is shown by large-screen lc, carries the printable output of mini-printer, also can realize Long-distance Control, data acquisition, data preservation by communication interface between grounded screen impedance specialized equipment and computer (RS232, USB) simultaneously;
The utility model can realize that the pulpit computer operation controls opening of earth loop impedance test equipment working power and disconnected, gives the impedance measuring equipment power transmission, operation detection, impedance ground value is qualified, record print, off device power supply, assurance safety.Earth loop impedance test equipment can operate at the scene, is provided with the execute-in-place priority function, mustn't be on-the-spot and microcomputer operate simultaneously;
The utility model is measured grounded screen impedance specialized equipment automatically by the transposition switch, can realize the measurement function of multi-point earth point impedance, and each point position impedance ground value preserved in record:
The utility model is automatically measured grounded screen impedance specialized equipment and is comprised design software and software for calculation.
The utlity model has following performance characteristics:
1, the power frequency equivalence of measuring is good: the measuring current waveform is sinusoidal wave, and the difference of frequency and power frequency is only 5Hz, uses 45Hz and two kinds of frequencies of 55Hz to measure.
2, anti-ground voltage interference performance is strong: the utility model adopts the alien frequencies method to measure, and coordinates modern software and hardware filtering technique, makes instrument have very high interference free performance, and test data is reliable and stable, and the error that 30V power frequency interference voltage brings is only 0.001 Ω.
3, precision is high: can be used to measure the very little large-scale earth mat of impedance ground.
4, powerful: as can to measure the complete characteristic parameter of the earthing device of correlation standard, not only can measure impedance ground, also can measure impedance component and reactive component; Can directly measure step voltage, step voltage, touch voltage, contact electricity, Potential distribution etc.
But 5 measure field are disturbed, and facilitate the user to estimate measuring error.
6, possess the break alarm function, avoided wrong measurement.
7, simple to operate: full menu in Chinese formula operation directly demonstrates measurement result.
8, can preserve 500 groups of above measurement data, but and carry mini-printer field print measurement result.
9, the wiring labor capacity is little, need not large electric current line.
10, volume is little, lightweight, is convenient for carrying.
11, have RS232 and USB communication interface, be equipped with client computer software, available computers software comes operating equipment.
Technical indicator of the present utility model is as follows:
● impedance measurement scope: 0～1000 Ω
● resolution: 0.001 Ω
● measuring error: ± (reading * 1%+0.001 Ω)
● anti-ground voltage interference performance: the error that 30V power frequency interference voltage brings is not more than 0.001 Ω (when measuring current is not less than 3A)
● measuring current waveform: sine wave
● measuring current frequency: 45Hz, 55Hz double frequency
● maximum output current: 5A
● maximum output voltage: 400V
● slotted line requires: electric current line copper core sectional area 〉=4.0mm
2
Pressure-wire copper core sectional area 〉=2.5mm
2
● power supply: AC220V ± 10%, 50Hz
● environment for use: temperature :-10 ℃～40 ℃; Relative humidity:＜90%.
Description of drawings
Below in conjunction with drawings and Examples, the utility model is described in further detail.
Fig. 1 is a kind of electrical principles block diagram of the present utility model.
Fig. 2 is a kind of electronic-circuit diagram of the present utility model.
Embodiment
Embodiment, a kind of automatic measurement grounded screen impedance means, with reference to Fig. 1, Fig. 2, formed by housing and electronic circuit, electronic circuit be the measuring current that produces of 45Hz/55Hz alien frequencies constant-current source circuit 1 by test output terminal C1, C2 on panel output, connect to measure after the measuring current that current amplification circuit 2 is obtained 1 output of 45Hz/55Hz alien frequencies constant-current source circuit by current transformer is amplified and switch and computing circuit 4; Connect to measure after the voltage amplification of voltage amplifier circuit 3 with measuring voltage input end P1, P2 acquisition on panel and switch and computing circuit 4; Measure to switch with computing circuit 4 and connect filtering circuit 5, filtering circuit 5 connects A/D change-over circuit and microcomputer systems 6, and the A/D change-over circuit is connected with microcomputer system and is connected display 7, printer 8 and RS232, USB interface 9, wherein:
45Hz/55Hz alien frequencies constant-current source circuit 1 is: 1 pin of four path analoging switch IC1 connects 6 pin of the operational amplifier A 4 of current amplification circuit 2, and 4 pin of four path analoging switch IC1 meet 6 pin of the operational amplifier A 3 of current amplification circuit 2,2 of four path analoging switch IC1, connect after 3 pin short circuits and measure to switch and 5 of resistance R 62, the four path analoging switch IC1 of computing circuit 4, connect 1 pin of the NPN Darlington transistor IC2 of built-in fly-wheel diode after 6 pin short circuits, 7 pin of four path analoging switch IC1 connect negative supply, and 8 pin series resistor R33 connect 6 pin of dual operational amplifier A5, the parallel connected end of resistance R 32, resistance R 32 meet 7 pin of dual operational amplifier A5,9 of four path analoging switch IC1, after 10 pin short circuits, series resistor R17 connects 3 pin of dual operational amplifier A5, the 11 pin connecting resistance R30 of four path analoging switch IC1, but the parallel connected end that the end of adjustable resistance RP1 is connected with the adjustable side, another termination of resistance R 30 is measured the resistance R 63 of switching with computing circuit 4, the parallel connected end of 8 pin of relay J 1 connects after the other end series resistor R3 of adjustable resistance RP1 and measures the resistance R 27 of switching with computing circuit 4, diode D15 negative pole, capacitor C 14, resistance R 85, resistance R 95, the parallel connected end of resistance R 39,12 of four path analoging switch IC1, connect after 13 pin short circuits built-in fly-wheel diode NPN Darlington transistor IC2 2, 5 pin, the 14 pin series resistor R18 of four path analoging switch IC1, No. 5 of junction plate key lead-in wires after R40, 1 pin of dual operational amplifier A5 meets triode T11, the base stage of T12, the collector of triode T11 connects 3 pin of the operational amplifier A 9 of filtering circuit 5, the emitter of triode T12 meets the telefault U2 of filtering circuit 5, capacitor C 6 negative poles, resistance R 100, 3 pin of operational amplifier A 10, the parallel connected end of resistance R 5, the collector of triode T12, the emitter of triode T11 connects measures the resistance R 47 of switching with computing circuit 4, capacitor C 28, 30 of the integrated circuit (IC) 9 of A/D change-over circuit and microcomputer system 6, 32, connect 2 pin of dual operational amplifier A5 after 35 parallel connected end and series resistor R10, 4 pin of dual operational amplifier A5 connect negative supply, 5 pin series resistor R34 connect and measure the resistance R 61 of switching with computing circuit 4, capacitor C 42, the resistance R 76 of current amplification circuit 2, capacitor C 39, resistance R 4, resistance R 70, the parallel connected end of measuring current output terminal C2, No. 5 lead-in wires of junction plate key after the 8 pin serial connection R40 of dual operational amplifier A5, 3, the 13 pin skies of the NPN Darlington transistor IC2 of built-in fly-wheel diode connect, 9,12 pin short circuits, 8,10 pin connect respectively negative supply, No. 5 of junction plate key lead-in wires after 14 pin series resistor R40, series resistor R99, light emitting diode LD5 are anodal, light emitting diode LD5 negative pole connects negative supply, 11 pin connect 10 pin of four nor gate IC4, connect No. 4 lead-in wires of negative supply, panel key after 4,6, the 7 pin short circuits of the NPN Darlington transistor IC2 of built-in fly-wheel diode,
1 of integrated pulse width modulation device IC3, 3, 16 pin skies connect, and 4, 5, 8, connect negative supply after 10 pin short circuits, the 2 pin connecting resistance R28 of integrated pulse width modulation device IC3 and capacitor C 13 parallel connected end, series resistor R27 connects and measures the diode D15 negative pole that switches with computing circuit 4, capacitor C 14, resistance R 31, resistance R 85, resistance R 39, the parallel connected end of resistance R 95, resistance R 28, connect negative supply after the other end parallel connection of capacitor C 13, the 6 pin series resistor R24 of integrated pulse width modulation device IC3,7 pin serial connection capacitor C 12,9 pin serial connection R23, connect negative supply after capacitor C 11,11 pin of integrated pulse width modulation device IC3 connect triode T6 base stage, the parallel connected end of resistance R 22, another termination negative supply of R22,14 pin of integrated pulse width modulation device IC3 connect triode T5 base stage, the parallel connected end of resistance R 21, another termination negative supply of resistance R 21,12 of integrated pulse width modulation device IC3, series resistor R25 after 13 pin short circuits, No. 5 of series resistor R40 junction plate key lead-in wires after the other end of resistance R 25 and 15 pin short circuits, triode T6, the collector of T5 connects respectively the two ends of transformer T power supply input winding, and the center tap of transformer T input winding connects+the 9V power supply, and the output winding two ends of transformer T connect respectively by diode D7, D8, D9, the input end of the bridge rectifier circuit that D10 forms, diode D7, D8, D9, the telefault U1 of the positive output termination filtering circuit 5 of the bridge rectifier circuit that D10 forms, capacitor C 7 positive poles, the parallel connected end of resistance R 19, the telefault U2 of negative output termination filtering circuit 5, the parallel connected end of capacitor C 8 negative poles, 3,4,9, the 11 pin skies of four nor gate IC4 connect, 1, No. 5 of series resistor R40 junction plate key lead-in wires after 2,12,13,14 pin short circuits, four nor gate 7 pin connect negative supply, 5, the end of connecting resistance R52 after 6 pin short circuits, the end of 8 pin serial connection adjustable resistance RP7 connecting resistance R53,10 pin, the serial connection capacitor C 10 that the other end parallel connection of resistance R 52, R53 is connected in series capacitor C 22 access four nor gate IC4 afterwards connect negative supply, connect 11 pin of the NPN Darlington transistor IC2 of built-in fly-wheel diode, connect the emitter of triode T9, the resistance R 51 of filtering circuit 5 after the base stage series resistor R41 of triode T7, the emitter of triode T7 connects the collector of triode T9, the collector of triode T7 connects the parallel connected end of measure switching with 2 pin of the resistance R OUT of computing circuit 4, relay J 4, the base stage of triode T9 connects the parallel connected end of capacitor C 4, diode D6 negative pole, D5 is anodal for the anodal serial connection of diode D6 voltage stabilizing diode, and the negative pole of voltage stabilizing diode D5 connects the emitter of the triode T8 that measures current output terminal C1, filtering circuit 5,
current amplification circuit 2 is: 5 pin skies of operational amplifier A 4 connect, 1 pin series resistor R66, adjustable resistance RP5, resistance R 68 connects 8 pin, 7 pin of the adjusting termination operational amplifier A 4 of adjustable resistance RP5, 7 pin of operational amplifier A 3, 2 pin connecting resistance R67 of operational amplifier A 4, the parallel connected end of resistance R 69, 6 pin of another termination operational amplifier A 4 of resistance R 67, 2 pin of another termination operational amplifier A 3 of resistance R 69, connecting resistance R76 after 3 pin series resistor R4 of operational amplifier A 4, capacitor C 39, measuring current output terminal C2, resistance R 70, measure the resistance R 61 of switching with computing circuit 4, capacitor C 42, resistance R 34 parallel connected end of 45Hz/55Hz alien frequencies constant-current source circuit 1, contact between the other end connecting resistance R77 serial connection R78 of capacitor C 39, another termination capacitor C 37 of resistance R 76, C38 parallel connected end, the other end connecting resistance R77 of capacitor C 38,5 pin of dual operational amplifier A2 connect the parallel connected end of 7,8 pin of dual operational amplifier A1 of the other end, the voltage amplifier circuit 3 of capacitor C 37 after the other end series resistor R78 of resistance R 77, 6 pin of operational amplifier A 4 connect 1 pin of four path analoging switch IC1 of 45Hz/55Hz alien frequencies constant-current source circuit 1, and 4 pin of operational amplifier A 4 connect negative supply, 1,5,8 pin skies of operational amplifier A 3 connect, 2 pin connecting resistance R69, and 3 pin connect the parallel connected end of adjustable resistance RP6, resistance R 71, but the other end of adjustable resistance RP6 and adjustable side series resistor R70 thereof meet measuring current output terminal C2, the other end serial connection capacitor C 31 of resistance R 71 connects 6,7 pin of dual operational amplifier A2, 4 pin of operational amplifier A 3 connect negative supply, 6 pin connect 4 pin, the resistance R 72 of four path analoging switch IC1 of 45Hz/55Hz alien frequencies constant-current source circuit 1, the parallel connected end of capacitor C 29, connect 1,2 pin of dual operational amplifier A2 after the other end parallel connection of resistance R 72, capacitor C 29 after series resistor R73, capacitor C 30, connect capacitor C 30 after 1, the 2 pin short circuits of dual operational amplifier A2,3 pin connect the resistance R 74 of voltage amplifier circuit 3, the parallel connected end of capacitor C 36,4 pin connect negative supply, 5 pin connect the contact between capacitor C 38 series resistor R77,6, connect the parallel connected end of the voltage stabilizing diode D21 positive pole of 8 pin that capacitor C 31,8 pin meet dual operational amplifier A1, filtering circuit 5 after 7 pin short circuits,
voltage amplifier circuit 3 is: 5 pin skies of operational amplifier A 6 connect, 1 pin series resistor R49, adjustable resistance RP10, resistance R 3 connects 8 pin, connect the anodal contact that is connected in series between capacitor C 7 negative poles of capacitor C 8 of filtering circuit 5 after 2 pin series resistor R91 of operational amplifier A 6, capacitor C 4, capacitor C 1, measure the resistance R 89 of switching with computing circuit 4, the parallel connected end of 3 pin of relay J 4, meet measuring voltage input end P2 after 3 pin series resistor R92 of operational amplifier A 6, resistance R 79 parallel connected end, 5 pin of another termination dual operational amplifier A1 of resistance R 79, 4 pin of operational amplifier A 6 connect negative supply, it is anodal that 6 pin meet diode D13, the parallel connected end of diode D20 negative pole, the anodal serial connection of diode D20 capacitor C 32 positive poles, capacitor C 32 negative poles connect negative supply, connect after diode D13 negative pole series resistor R90 and measure the resistance R 89 of switching with computing circuit 4, the parallel connected end of adjustable resistance RP9, 7 pin connect the adjustable side of adjustable resistance RP10, No. 5 lead-in wires of junction plate key after serial connection R40, 1 of dual operational amplifier A1, contact after 2 pin short circuits between connecting resistance R75 serial connection capacitor C 35, the other end connecting resistance R74 of resistance R 75, the parallel connected end of capacitor C 34, 3 pin of another termination dual operational amplifier A2 of resistance R 74, the parallel connected end of capacitor C 36, the other end connecting resistance R65 of capacitor C 36, the parallel connected end of the other end of capacitor C 35, another termination capacitor C 34 of resistance R 65, contact between the other end connecting resistance R75 series resistor R74 of capacitor C 34, 3 pin of dual operational amplifier A1 meet measuring voltage input end P1, the parallel connected end of resistance R 50, another termination of resistance R 50 is measured 5 pin of the four high guaily unit IC5 of switching and computing circuit 4, the parallel connected end of resistance R 86, 4 pin of dual operational amplifier A1 connect negative supply, 6, connect the resistance R 78 of current amplification circuit 2 after 7 pin short circuits, the parallel connected end of capacitor C 37, 8 pin of 8 pin and dual operational amplifier A2 and to connect the voltage stabilizing diode D21 of filtering circuit 5 anodal,
measure to switch with computing circuit 4 and be: 5 pin skies of operational amplifier A 7 connect, 1 pin series resistor R59, adjustable resistance RP4, resistance R 60 connects 8 pin, 2 pin connecting resistance R63, capacitor C 40, the parallel connected end of resistance R 64,1 pin of another relay termination J1 of resistance R 63, the resistance R 30 of 45Hz/55Hz alien frequencies constant-current source circuit 1, resistance R 64, 6 pin of another termination operational amplifier A 7 of capacitor C 40 parallel connections, but an end and the adjustable side thereof of adjustable resistance RP8, the parallel connected end of resistance R 58,2 pin of another relay termination J1 of resistance R 58, the parallel connected end of resistance R 61, another termination capacitor C 42 of resistance R 61, the resistance R 34 of 45Hz/55Hz alien frequencies constant-current source circuit 1, measuring current output terminal C2, the resistance R 70 of current amplification circuit 2, resistance R 76, resistance R 4, the parallel connected end of capacitor C 39,3 pin of another relay termination J1 of adjustable resistance RP8,3 pin connecting resistance R62 of operational amplifier A 7, the parallel connected end of capacitor C 27,2 of four path analoging switch IC1 of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of resistance R 62, 3 pin, 4 pin of another termination operational amplifier A 7 of capacitor C 27,4 pin of operational amplifier A 7 connect negative supply, but 7 pin of operational amplifier A 7 connect the adjustable side of adjustable resistance RP4, 7 pin of operational amplifier A 8 etc. are connected in series No. 5 lead-in wires of junction plate key after R40 together, 5 pin skies of operational amplifier A 8 connect, 1 pin series resistor R55, adjustable resistance RP3, resistance R 56 connects 8 pin, 2 pin connecting resistance R57, the parallel connected end of capacitor C 41, the other end connecting resistance R46 of resistance R 57, capacitor C 28, the parallel connected end of resistance R 54, resistance R 54, the other end of capacitor C 41 also connects 6 pin of operational amplifier A 8, the end of resistance R OUT, the collector of the triode T7 of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of resistance R OUT, 2 pin of relay J 4, 1 pin of another relay termination J1 of resistance R 46, connect after 3 pin series resistor R47 of operational amplifier A 8 A/D change-over circuit and microcomputer system 6 integrated circuit (IC) 9 30, 32, 35 parallel connected end, the other end of capacitor C 28, the emitter of the triode T11 of 45Hz/55Hz alien frequencies constant-current source circuit 1, the collector of triode T12, the parallel connected end of resistance R 10, 4 pin of operational amplifier A 8 connect negative supply, but 7 pin connect the adjustable side of adjustable resistance RP3, No. 5 lead-in wires of junction plate key after serial connection R40, 1 pin of four high guaily unit IC5 connects 4 pin of the operational amplifier A 9 of filtering circuit 5, 7 pin of operational amplifier A 10 connect 10 pin after the 2 pin series resistor R38 of four high guaily unit IC5, and 10 pin series resistor R37 connect 8 pin, and it is anodal that 8 pin meet diode D17, and diode D17 negative pole connects 6 pin of four XOR gate IC6, series resistor R48 connects 7 pin of four XOR gate IC6, capacitor C 20 positive poles, the parallel connected end of resistance R 45, the 3 pin connecting resistance R85 of four high guaily unit IC5, the parallel connected end of R84, the other end connecting resistance R27 of resistance R 85, capacitor C 14, the parallel connected end of diode D15, contact between resistance R 95 serial connection R39, another termination negative supply of resistance R 84,4 of four high guaily unit IC5, serial connection capacitor C 24 between 11 pin, No. 5 lead-in wires of junction plate key after the 4 pin serial connection R40 of four high guaily unit IC5, resistance R 15, the parallel connected end of resistance R 14,13 pin of another termination four XOR gate IC6 of resistance R 15, series resistor R12 succeeds 1 pin of electrical equipment J2,1 pin of another termination four XOR gate IC6 of resistance R 14, succeed 7 pin of electrical equipment J1 after series resistor R11, the 5 pin connecting resistance R50 of four high guaily unit IC5, the parallel connected end of resistance R 86, another termination measuring voltage input end P1 of resistance R 50,6 pin of another relay termination J4 of resistance R 86, the 6 pin series resistor R87 of four high guaily unit IC5 connect 7 pin, the end of 7 pin connecting resistance R88, but connect the resistance R 90 of voltage amplifier 3 behind the other end of resistance R 88 serial connection adjustable resistance RP9 and adjustable side thereof, succeed 3 pin of electrical equipment J4 after the other end series resistor R89 of adjustable resistance RP9, contact between the anodal serial connection capacitor C of capacitor C 87 negative poles of filtering circuit 5, capacitor C 4, capacitor C 1, the parallel connected end of the resistance R 91 of voltage amplifier 3, the 9 pin connecting resistance R35 of four high guaily unit IC5, be connected in series No. 5 lead-in wires of junction plate key after R40 together with the parallel connected end of R36,7 pin of the other end of resistance R 35 and operational amplifier A 8 etc., another termination negative supply of resistance R 36, the 12 pin connecting resistance R19 of four high guaily unit IC5, the parallel connected end of resistance R 20, capacitor C 7 positive poles of another termination filtering circuit 5 of resistance R 19, telefault U1, by diode D7, D8, D9, the positive output end of the bridge rectifier that D10 forms, another termination negative supply of resistance R 20,13 of four high guaily unit IC5, 14 pin short circuits, the 4 pin skies of four XOR gate IC6 connect, 1 pin connecting resistance R14, the parallel connected end of resistance R 11, the other end connecting resistance R15 of resistance R 14, No. 5 lead-in wires of junction plate key after serial connection R40,7 pin of another relay termination J1 of resistance R 11,2 of four XOR gate IC6, 5, 9, connect 21 pin of the integrated circuit (IC) 9 of A/D change-over circuit and microcomputer system 6 after 12 pin short circuits, 3 of four XOR gate IC6, 10, 11 pin connect respectively 28 of display 7, 36, 32 pin, the 6 pin connecting resistance R48 of four XOR gate IC6, the parallel connected end of diode D17 negative pole, 7 pin of another termination four XOR gate IC6 of resistance R 48, capacitor C 20 positive poles, resistance R 45, 31 of the integrated circuit (IC) 9 of A/D change-over circuit and microcomputer system 6, 37 pin parallel connected end, 1 pin of another relay termination J4 of resistance R 45, the negative pole of capacitor C 20 connects negative supply, the 8 pin connecting resistance R16 of four XOR gate IC6, the parallel connected end of R13,1 pin of another relay termination J3 of resistance R 13,2 pin of another termination JK1 of resistance R 16, C3 is anodal, 1 pin parallel connected end of the integrated circuit (IC) 9 of A/D change-over circuit and microcomputer system 6, the 13 pin connecting resistance R15 of four XOR gate IC6, the parallel connected end of resistance R 12, No. 5 of junction plate key lead-in wires after the other end connecting resistance R14 series resistor R40 of resistance R 15,1 pin of another relay termination J2 of resistance R 12, the 14 pin connecting resistance R9 of four XOR gate IC6, resistance R 39, the parallel connected end of capacitor C 33,16 pin of the trigger IC7 of another termination filtering circuit 5 of resistance R 9, the capacitor C 9 of 45Hz/55Hz alien frequencies constant-current source circuit 1, the parallel connected end of the pin of connection terminal JK1, the other end connecting resistance R85 of resistance R 39, the capacitor C 14 of 45Hz/55Hz alien frequencies constant-current circuit 1, diode D15 negative pole, resistance R 27, resistance R 31, the parallel connected end of resistance R 95, the other end serial connection adjustable resistance RP2 of resistance R 95, connect the anodal contact that is connected in series between capacitor C 5 negative poles of capacitor C 6 of filtering circuit 5 after resistance R 96,36 pin of the integrated circuit (IC) 9 of the regulated termination A/D change-over circuit of adjustable resistance RP2 and microcomputer system (6),
filtering circuit 7 is: 1 of trigger IC7, 12, 15 pin skies connect, 2 pin connecting resistance R83, the parallel connected end of light emitting diode LD1 positive pole, 5 pin connecting resistance R82, the parallel connected end of light emitting diode LD2 positive pole, 7 pin connecting resistance R81, the parallel connected end of light emitting diode LD3 positive pole, 10 pin connecting resistance R80, the parallel connected end of light emitting diode LD4 positive pole, light emitting diode LD1, LD2, LD3, after the negative pole parallel connection of LD4, series resistor R26 connects negative supply, resistance R 80, R81, R82, the other end of R83 meets respectively triode T1, T2, T3, the base stage of T4, the coil of the collector connecting relay J1 of triode T1, the parallel connected end of diode D19 positive pole, the coil of the collector connecting relay J2 of triode T2, the parallel connected end of diode D18 positive pole, the coil of the collector connecting relay J3 of triode T3, the parallel connected end of diode D16 positive pole, the coil of the collector connecting relay J4 of triode T4, the parallel connected end of diode D14 positive pole, relay J 1, J2, J3, the other end of J4 coil and diode D19, D18, D16, meet+the 9V power supply 3 of trigger IC7 after the negative pole parallel connection of D14, 4, 6, 11 pin are series diode D1 respectively, D2, D11, D12 is anodal, diode D1, D2, D11, 9 pin of contact hair device IC7 after the negative pole short circuit of D12,8 of trigger IC7, 13, meet triode T1 after 14 pin short circuits, T2, T3, the parallel connected end of T4 emitter, negative supply, resistance R 97, R98, R93, parallel end connection capacitor C 3 negative poles of R94, capacitor C 3 positive poles connect 2 pin of connection terminal JK1, measure the resistance R 16 of switching with computing circuit 4, 1 pin parallel connected end of the integrated circuit (IC) 9 of A/D change-over circuit and microcomputer system 6, resistance R 97, R98, R93, 6 of the other end difference junction plate key of R94, 7, 8, No. 9 lead-in wires, 16 pin of trigger IC7 connect measures the resistance R 9 of switching with computing circuit 4, the parallel connected end of capacitor C 9, 3 pin of connection terminal JK1, 1,5,8 pin skies of operational amplifier A 10 connect, and 2 pin connect the collector of triode T8, and 3 pin of operational amplifier A 10 connect the parallel connected end of contact between telefault U2 serial connection capacitor C 6 negative poles of filtering circuit 5, resistance R 5, resistance R 100, another termination voltage stabilizing diode D3 of resistance R 5 is anodal, the parallel connected end of D4 negative pole, one termination negative supply of the negative pole of voltage stabilizing diode D3 and resistance R 51, 4 pin of another termination operational amplifier A 10 of resistance R 100, the parallel connected end of the positive pole of voltage stabilizing diode D4, 6 pin of operational amplifier A 10 connect the base stage of triode T8, the emitter of triode T8 meets measuring current output terminal C1, the negative pole of the voltage stabilizing diode D5 of 45Hz/55Hz alien frequencies constant-current source circuit 1, 7 pin of operational amplifier A 10 connect 4 pin of operational amplifier A 9, measure 1 pin of the four high guaily unit IC5 of switching and computing circuit 4, 1 of operational amplifier A 9, 5, 8 pin skies connect, and 2 pin connect triode T10 collector, the parallel connected end of resistance R 1, the parallel end connection voltage stabilizing diode D21 negative pole of the other end of resistance R 1 and resistance R 2, the parallel connected end of voltage stabilizing diode D22 positive pole, the positive pole of voltage stabilizing diode D21 connect 8 pin of the dual operational amplifier A1 of voltage amplifier circuit 3, 8 pin of the dual operational amplifier A2 of current amplification circuit 2, after the other end series resistor R6 of resistance R 2 with 7 pin of operational amplifier A 9, the negative pole of voltage stabilizing diode D22 meets telefault U1 together, the parallel connected end of capacitor C 5 positive poles, the diode D7 of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of telefault U1, D8, D9, the positive output end of the bridge rectifier that D10 forms, the positive pole of capacitor C 7, measure the parallel connected end of the resistance R 19 in switching and computing circuit 4, the negative pole of capacitor C 5 connects the positive pole of capacitor C 6, measure the parallel connected end of the resistance R 96 of switching and computing circuit 4, the negative pole of capacitor C 6 meets telefault U2, 3 pin of the operational amplifier A 10 of 45Hz/55Hz alien frequencies constant-current source circuit 1, resistance R 100, the parallel connected end of resistance R 5, the negative pole of another termination capacitor C 8 of telefault U2, the diode D7 of 45Hz/55Hz alien frequencies constant-current circuit 1, D8, D9, the negative output terminal of the bridge rectifier that D10 forms, the positive pole of capacitor C 8 connects capacitor C 7 negative poles, capacitor C 4, the parallel connected end of capacitor C 1 grade, 3 pin of operational amplifier A 9 connect the collector of the triode T11 of 45Hz/55Hz alien frequencies constant-current source circuit 1,6 pin of operational amplifier A 9 connect the base stage of triode T10 and the parallel connected end of capacitor C 2, the emitter of triode T10 connects serial connection capacitor C 1 after the other end of capacitor C 2, the other end serial connection capacitor C 4 of capacitor C 1, contact between capacitor C 7 negative pole serial connection C8 positive poles, the resistance R 91 of voltage amplifier circuit 3, measure the resistance R 89 of switching with computing circuit 4, the parallel connected end of 3 pin of relay J 4, the triode T9 base stage of another termination 45Hz/55Hz alien frequencies constant-current source circuit 1 of capacitor C 4 and the parallel connected end of diode D6 negative pole, capacitor C 7 positive poles meet telefault U1, diode D7, D8, D9, the positive output end of the bridge rectifier that D10 forms, measure to switch the parallel connected end with the resistance R 19 of computing circuit 4, the A/D change-over circuit is connected with microcomputer system and is connected display 7 by conventional method, printer 8 and RS232, USB interface 9, in the present embodiment, four path analoging switch IC1 are CD4066, the NPN Darlington transistor IC2 of built-in fly-wheel diode is CD4031, integrated pulse width modulation device IC3 is LM3524, four nor gate IC4 is CD4001, four high guaily unit IC5 is LM324, four XOR gate IC6 are CD4070, trigger IC7 is MC14174, integrated circuit (IC) 9 is T106, and this consists of a kind of structure of the present utility model.
electronic circuit of the present utility model is that the measurement continuous current that produces of 45Hz/55Hz alien frequencies constant-current source circuit 1 is by the C1 on housing, the output of C2 terminal, the electric current that current amplification circuit 2 is obtained 1 output of 45Hz/55Hz alien frequencies constant-current source circuit by current transformer amplifies, flow to the filtering circuit 5 for filtering interference signals, filtering circuit 5 only keeps the electric current output of 45Hz/55Hz, voltage amplifier circuit 5 is with measuring voltage input end P1 on housing, the voltage amplification that P2 obtains, flow to the filtering circuit 5 for filtering interference signals, filtering circuit 5 only keeps the voltage waveform input of 45Hz/55Hz, filtering circuit 5 connects A/D change-over circuit and microcomputer system 6, the A/D change-over circuit is that digital signal is exported to microcomputer system and processed with analog signal conversion, the A/D change-over circuit is connected with microcomputer system and is connected display 7 and printer 8, result is after treatment exported at display 7 or by printer 8, RS232, USB communication interface 9 is used for connecting external unit, the specific works principle is as follows:
45Hz/55Hz alien frequencies constant-current source circuit 1 exportable frequency is the sinusoidal wave measuring current of 45Hz or 55Hz, output frequency is controlled by the microcomputer system of A/D change-over circuit and microcomputer system 6, its output through the isolation after by the C1 on case panel, two terminal outputs of C2, voltage amplifier circuit 3 is a high input impedance amplifier, it is with P1, give filtering circuit 5 after the voltage amplification at P2 two ends, current amplification circuit 2 will be given filtering circuit 5 after amplifying from the current signal that current transformer is obtained, filtering circuit 5 is used for filtering interference signals, only allow 45Hz and 55Hz signal to pass through, A/D change-over circuit in A/D change-over circuit and microcomputer system 6 is used for aanalogvoltage and current signal are converted to digital signal so that microcomputer system is analyzed, process.
After the user starts grid grounding impedance measurement, at first the utility model is opened 45Hz/55Hz alien frequencies constant-current source circuit 1 and is made it the electric current that output frequency is 45Hz, after treating current stabilization, microcomputer system in A/D change-over circuit and microcomputer system 6 is obtained the voltage and current Wave data by the A/D change-over circuit, carries out calculating voltage V after digital filtering
45And electric current I
45And phase differential, more further calculate impedance Z
45, impedance component R
45With reactive component X
45Then the output frequency that switches 45Hz/55Hz alien frequencies constant-current source circuit 1 is 55Hz, can calculate impedance Z through after same step
55, impedance component R
55With reactive component X
55Get Z
45And Z
55Mean value as the power-frequency earthing impedance Z
50, last, close 45Hz/55Hz alien frequencies constant-current source circuit 1, by display 7 display measurement results; Therefore during impedance measurement, apparatus measures be the ratio of voltage and testing power supply output current between two measuring voltage input end P1, P2.
Advantage and the principle of work of this device are as follows:
1,45Hz/55Hz alien frequencies constant-current source circuit 1:
this device adopts advanced PWM integrated pulse width modulation device IC3, the large transistor npn npn of high reliability, the microminiature isolating transformer of high permeability etc. to form core devices, 9 volts of direct supplys flow under the effect of output signals at 11 pin, 14 castors of integrated pulse width modulation device IC3, control conducting and the cut-off of triode T6, T5, the time of its conducting is determined by the timing resistor value of 6 pin of integrated pulse width modulation device IC3 and the timing capacitor value of 7 pin, inner two the transistorized outputs in parallel of integrated pulse width modulation device IC3 have strengthened its triggering ability to inverter transistor, have improved the correctness of alien frequencies, have guaranteed the reliability of tester, different pulse widths has formed the sine wave test alternating current of 45Hz or 55Hz, and this electric current is after transformer isolation, by the C1 on panel, two testing current terminal outputs of C2, the NPN Darlington transistor IC2 that switch by dual operational amplifier A5, four path analoging switch IC1, built-in fly-wheel diode in alien frequencies continuous current source forms, the 1st of four path analoging switch IC1 and the 2nd switch, the 3rd and the 4th switch in parallel are used, and its control is another combination, and the 1st and the 3rd switch, the 2nd and the 4th switch be shared control signals respectively, what first switch of four path analoging switch IC1 was introduced is the signal of the operational amplifier A 4 of current amplification circuit 2, what second switch introduced is current amplification circuit 2, the combination of operational amplifier A 3 signals of voltage amplifier circuit 3, what the 3rd switch introduced is the current signal of dual operational amplifier A5 output, the 4th switch introduced is through the composite signal of the relay J 1 of R30 access with through RP1, R31 access from integrated pulse width modulation device IC3, the composite signal of four high guaily unit IC5 etc., above these signals are 2 of the NPN of built-in fly-wheel diode Darlington transistor IC2, carry out under the instruction that 5 and 1 human hair combing waste goes out 45Hz the switching of 55Hz alien frequencies constant-current supply, measure and switch with computing circuit 4 take trigger IC7 as core component, send different measurement composite signals under the instruction of microcomputer system, carried out by different relays, complete various test functions.
2, current amplification circuit 2:
current amplification circuit 2 is comprised of 5,6,7,8 pin, operational amplifier A 3, operational amplifier A 4, operational amplifier A 5 and resistance R 76, resistance R 77, resistance R 78, capacitor C 37, capacitor C 38, the capacitor C 39 of the 2nd operational amplifier of dual operational amplifier A2 RC networking etc. forms, test current signals C2 is through resistance R 70, send into positive input 3 pin of operational amplifier A 3 together with the signal of the emitter follower output that forms with the 2nd operational amplifier of dual operational amplifier A2 after adjustable resistance RP6 takes out, another road of test current signals C2 is through positive input 3 pin of resistance R 4 input operational amplifier A4, access is by resistance R 76, capacitor C 38, resistance R 77, resistance R 78, capacitor C 37, the RC network of the compositions such as capacitor C 39 is carried out computing, positive input 5 pin of the 2nd amplifier of one end input dual operational amplifier A2 of this network, test current signals C2 also inputs positive input 5 pin of the 2nd operational amplifier of dual operational amplifier A5 through resistance R 34, after amplifying, ratio sends into 8 pin of four path analoging switch IC1, the current signal that operational amplifier A 4 is amplified ratio computing exports 1 pin of four path analoging switch IC1 to through 6 pin, the output of the 1st operational amplifier 1 pin of the dual operational amplifier A2 on voltage amplification point road 3 and the current operator signal of operational amplifier A 3 are inputted 4 pin of four path analoging switch IC1 together.
3, voltage amplifier circuit 3:
RC network that voltage amplifier circuit 3 is comprised of 5,6,7 pin of the 2nd operational amplifier of 1,2,3,4 pin of the 1st operational amplifier of dual operational amplifier A1, dual operational amplifier A2, operational amplifier A 6, double operational IC5 and capacitor C 12, resistance R 74, resistance R 75, capacitor C 35, resistance R 65, capacitor C 34, capacitor C 29, resistance R 72, resistance R 73, capacitor C 30 etc. forms, measurement voltage signal introduced by P1 dual operational amplifier A1 the 1st operational amplifier positive input 3 pin and introduce positive input 5 pin of the 2nd operational amplifier of four high guaily unit IC5 324 through resistance R 50, the 2nd operational amplifier of four high guaily unit IC5 324 7 pin after ratio is amplified output to reverse input end 2 pin of operational amplifier A 6, measure the signal that switches and enter 3 pin of relay J 4, filtering circuit 5, another road voltage signal introduced by measuring voltage input end P2 dual operational amplifier A1 the 2nd operational amplifier positive input 5 pin and introduce positive input 3 pin of operational amplifier A 6 through resistance R 92, 6 pin outputs of operational amplifier A 6 are through diode D13, enter 3 pin of relay J 4 together with the output of resistance R 90 and the 2nd operational amplifier 7 pin of four high guaily unit IC5, the output of emitter follower 1 pin that the 1st amplifier of dual operational amplifier A1 forms enters positive input 5 pin of the 2nd operational amplifier of the RC network input dual operational amplifier A2 that is comprised of resistance R 75, resistance R 74, capacitor C 36, capacitor C 35, resistance R 65, capacitor C 34, and its 7 pin output enters 3 pin of relay J 4 together with the output signal of the RC network of capacitor C 30, resistance R 73, resistance R 72, capacitor C 29 compositions and operational amplifier A 3 current amplifier 6 pin.
4, measure switching and computing circuit 4:
Measure to switch with computing circuit 4 and formed by operational amplifier A 7, operational amplifier A 8, relay J 1, J2, J3, J4, double operational IC5, four XOR gate IC6 etc.; Relay J 1, J2, J3, J4 by the different contact combination in inside, provide predefined compute mode required various parameter combinations to operational amplifier, and operation result are transported to filter circuit 5 under the driving of measuring switching command.
5, filtering circuit 5:
Filtering circuit 5 is comprised of two cover ∏ mode filters and operational amplifier A 9, the operational amplifier A 10 that capacitor C 8, capacitor C 6, telefault U2 and capacitor C 7, capacitor C 5, telefault U1 form; Filtering circuit 5 only allows the signal of 45Hz, 55Hz frequency to pass through through special designs, filtering be attached to undesired signal on the power frequency waveform, guaranteed the accuracy of measurement result.
6, A/D change-over circuit and microcomputer system 6:
A/D Collect conversion device, storer, latch, code translator will be the digital signal that microprocessor can be accepted and process through measurement, operation amplifier, filtered analog signal conversion, singlechip microprocessor is through programming, send all multiple instruction such as test, switching, computing, Display and Print, for the realization of guaranteeing the test mass target provides reliable technical guarantee.
7, LCD display 7
Adopt LCDs, with directly perceived, clear, careful reflecting of information such as the various functions of tester, various test results.
8, printer 8:
In order in test site, test result to be compared and other needs, be equipped with printer.
9, RS232, USB interface 9:
In order to facilitate the user to utilize computer software operating instrument and the more test data of storage and the instrumentation software of in time upgrading, adopted the components and parts such as MAX232, FT232BL, be provided with RS232, USB interface.
Claims (6)
1. automatically measure the grounded screen impedance means for one kind, formed by housing and electronic circuit, it is characterized in that electronic circuit be the measuring current that produces of 45Hz/55Hz alien frequencies constant-current source circuit (1) by test output terminal C1, C2 on panel output, connect to measure after the measuring current that current amplification circuit (2) is obtained 45Hz/55Hz alien frequencies constant-current source circuit (1) output by current transformer is amplified and switch and computing circuit (4); Connect to measure after the voltage amplification of voltage amplifier circuit (3) with measuring voltage input end P1, P2 acquisition on panel and switch and computing circuit (4); Measure to switch with computing circuit (4) and connect filtering circuit (5), filtering circuit (5) connects A/D change-over circuit and microcomputer system (6), and the A/D change-over circuit is connected 6 with microcomputer system) connect display (7) and printer (8) and RS232, USB communication interface (9).
2. a kind of automatic measurement grounded screen impedance means according to claim 1 is characterized in that described 45Hz/55Hz alien frequencies constant-current source circuit (1) is:
1 pin of four path analoging switch IC1 connects 6 pin of the operational amplifier A 4 of current amplification circuit (2), and 4 pin of four path analoging switch IC1 meet 6 pin of current amplification circuit (2) operational amplifier A 3,2 of four path analoging switch IC1, connect after 3 pin short circuits and measure to switch and 5 of resistance R 62, the four path analoging switch IC1 of computing circuit (4), connect 1 pin of the NPN Darlington transistor IC2 of built-in fly-wheel diode after 6 pin short circuits, 7 pin of four path analoging switch IC1 connect negative supply, and 8 pin series resistor R33 connect 6 pin of dual operational amplifier A5, the parallel connected end of resistance R 32, resistance R 32 meet 7 pin of dual operational amplifier A5,9 of four path analoging switch IC1, after 10 pin short circuits, series resistor R17 connects 3 pin of dual operational amplifier A5, the 11 pin connecting resistance R30 of four path analoging switch IC1, but the parallel connected end that the end of adjustable resistance RP1 is connected with the adjustable side, another termination of resistance R 30 is measured the resistance R 63 of switching with computing circuit (4), the parallel connected end of 8 pin of relay J 1 connects after the other end series resistor R3 of adjustable resistance RP1 and measures the resistance R 27 of switching with computing circuit (4), diode D15 negative pole, capacitor C 14, resistance R 85, resistance R 95, the parallel connected end of resistance R 39,12 of four path analoging switch IC1, connect after 13 pin short circuits built-in fly-wheel diode NPN Darlington transistor IC2 2, 5 pin, the 14 pin series resistor R18 of four path analoging switch IC1, No. 5 of junction plate key lead-in wires after R40,
1 pin of dual operational amplifier A5 meets triode T11, the base stage of T12, the collector of triode T11 connects 3 pin of the operational amplifier A 9 of filtering circuit (5), the emitter of triode T12 meets the telefault U2 of filtering circuit (5), capacitor C 6 negative poles, resistance R 100, 3 pin of operational amplifier A 10, the parallel connected end of resistance R 5, the collector of triode T12, the emitter of triode T11 connects measures the resistance R 47 of switching with computing circuit (4), capacitor C 28, A/D change-over circuit and microcomputer system (6) parallel connected end and series resistor R10 after connect 2 pin of dual operational amplifier A5, 4 pin of dual operational amplifier A5 connect negative supply, 5 pin series resistor R34 connect and measure the resistance R 61 of switching with computing circuit (4), capacitor C 42, the resistance R 76 of current amplification circuit (2), capacitor C 39, resistance R 4, resistance R 70, the parallel connected end of measuring current output terminal C2, No. 5 lead-in wires of junction plate key after the 8 pin serial connection R40 of dual operational amplifier A5,
3, the 13 pin skies of the NPN Darlington transistor IC2 of built-in fly-wheel diode connect, 9,12 pin short circuits, 8,10 pin connect respectively negative supply, No. 5 of junction plate key lead-in wires after 14 pin series resistor R40, series resistor R99, light emitting diode LD5 are anodal, light emitting diode LD5 negative pole connects negative supply, 11 pin connect 10 pin of four nor gate IC4, connect No. 4 lead-in wires of negative supply, panel key after 4,6, the 7 pin short circuits of the NPN Darlington transistor IC2 of built-in fly-wheel diode;
1 of integrated pulse width modulation device IC3, 3, 16 pin skies connect, and 4, 5, 8, connect negative supply after 10 pin short circuits, the 2 pin connecting resistance R28 of integrated pulse width modulation device IC3 and capacitor C 13 parallel connected end, series resistor R27 connects and measures the diode D15 negative pole that switches with computing circuit (4), capacitor C 14, resistance R 31, resistance R 85, resistance R 39, the parallel connected end of resistance R 95, resistance R 28, connect negative supply after the other end parallel connection of capacitor C 13, the 6 pin series resistor R24 of integrated pulse width modulation device IC3,7 pin serial connection capacitor C 12,9 pin serial connection R23, connect negative supply after capacitor C 11,11 pin of integrated pulse width modulation device IC3 connect triode T6 base stage, the parallel connected end of resistance R 22, another termination negative supply of R22,14 pin of integrated pulse width modulation device IC3 connect triode T5 base stage, the parallel connected end of resistance R 21, another termination negative supply of resistance R 21,12 of integrated pulse width modulation device IC3, series resistor R25 after 13 pin short circuits, No. 5 of series resistor R40 junction plate key lead-in wires after the other end of resistance R 25 and 15 pin short circuits, triode T6, the collector of T5 connects respectively the two ends of transformer T power supply input winding, and the center tap of transformer T input winding connects+the 9V power supply, and the output winding two ends of transformer T connect respectively by diode D7, D8, D9, the input end of the bridge rectifier circuit that D10 forms, diode D7, D8, D9, the telefault U1 of the positive output termination filtering circuit (5) of the bridge rectifier circuit that D10 forms, capacitor C 7 positive poles, the parallel connected end of resistance R 19, the telefault U2 of negative output termination filtering circuit (5), the parallel connected end of capacitor C 8 negative poles,
3,4,9, the 11 pin skies of four nor gate IC4 connect, 1, No. 5 of series resistor R40 junction plate key lead-in wires after 2,12,13,14 pin short circuits, four nor gate 7 pin connect negative supply, 5, the end of connecting resistance R52 after 6 pin short circuits, the end of 8 pin serial connection adjustable resistance RP7 connecting resistance R53,10 pin, the serial connection capacitor C 10 that the other end parallel connection of resistance R 52, R53 is connected in series capacitor C 22 access four nor gate IC4 afterwards connect negative supply, connect 11 pin of the NPN Darlington transistor IC2 of built-in fly-wheel diode;
Connect the emitter of triode T9, the resistance R 51 of filtering circuit (5) after the base stage series resistor R41 of triode T7, the emitter of triode T7 connects the collector of triode T9, the collector of triode T7 connects the parallel connected end of measure switching with 2 pin of the resistance R OUT of computing circuit (4), relay J 4, the base stage of triode T9 connects the parallel connected end of capacitor C 4, diode D6 negative pole, D5 is anodal for the anodal serial connection of diode D6 voltage stabilizing diode, and the negative pole of voltage stabilizing diode D5 connects the emitter of the triode T8 that measures current output terminal C1, filtering circuit (5).
3. a kind of automatic measurement grounded screen impedance means according to claim 1 is characterized in that described current amplification circuit (2) is:
5 pin skies of operational amplifier A 4 connect, 1 pin series resistor R66, adjustable resistance RP5, resistance R 68 connects 8 pin, 7 pin of the adjusting termination operational amplifier A 4 of adjustable resistance RP5, 7 pin of operational amplifier A 3, 2 pin connecting resistance R67 of operational amplifier A 4, the parallel connected end of resistance R 69, 6 pin of another termination operational amplifier A 4 of resistance R 67, 2 pin of another termination operational amplifier A 3 of resistance R 69, connecting resistance R76 after 3 pin series resistor R4 of operational amplifier A 4, capacitor C 39, measuring current output terminal C2, resistance R 70, measure the resistance R 61 of switching with computing circuit (4), capacitor C 42, resistance R 34 parallel connected end of 45Hz/55Hz alien frequencies constant-current source circuit (1), contact between the other end connecting resistance R77 serial connection R78 of capacitor C 39, another termination capacitor C 37 of resistance R 76, C38 parallel connected end, the other end connecting resistance R77 of capacitor C 38,5 pin of dual operational amplifier A2 connect the parallel connected end of 7,8 pin of dual operational amplifier A1 of the other end, the voltage amplifier circuit (3) of capacitor C 37 after the other end series resistor R78 of resistance R 77, 6 pin of operational amplifier A 4 connect 1 pin of four path analoging switch IC1 of 45Hz/55Hz alien frequencies constant-current source circuit (1), and 4 pin of operational amplifier A 4 connect negative supply,
1,5,8 pin skies of operational amplifier A 3 connect, 2 pin connecting resistance R69, and 3 pin connect the parallel connected end of adjustable resistance RP6, resistance R 71, but the other end of adjustable resistance RP6 and adjustable side series resistor R70 thereof meet measuring current output terminal C2; The other end serial connection capacitor C 31 of resistance R 71 connects 6,7 pin of dual operational amplifier A2; 4 pin of operational amplifier A 3 connect negative supply, 6 pin connect 4 pin, the resistance R 72 of four path analoging switch IC1 of 45Hz/55Hz alien frequencies constant-current source circuit (1), the parallel connected end of capacitor C 29, connect 1,2 pin of dual operational amplifier A2 after the other end parallel connection of resistance R 72, capacitor C 29 after series resistor R73, capacitor C 30;
Connect capacitor C 30 after 1, the 2 pin short circuits of dual operational amplifier A2,3 pin connect the resistance R 74 of voltage amplifier circuit (3), the parallel connected end of capacitor C 36,4 pin connect negative supply, 5 pin connect the contact between capacitor C 38 series resistor R77,6, connect the parallel connected end of the voltage stabilizing diode D21 positive pole of 8 pin that capacitor C 31,8 pin meet dual operational amplifier A1, filtering circuit (5) after 7 pin short circuits.
4. a kind of automatic measurement grounded screen impedance means according to claim 1 is characterized in that described voltage amplifier circuit (3) is:
5 pin skies of operational amplifier A 6 connect, 1 pin series resistor R49, adjustable resistance RP10, resistance R 3 connects 8 pin, connect the anodal contact that is connected in series between capacitor C 7 negative poles of capacitor C 8 of filtering circuit (5) after 2 pin series resistor R91 of operational amplifier A 6, capacitor C 4, capacitor C 1, measure the resistance R 89 of switching with computing circuit (4), the parallel connected end of 3 pin of relay J 4, meet measuring voltage input end P2 after 3 pin series resistor R92 of operational amplifier A 6, resistance R 79 parallel connected end, 5 pin of another termination dual operational amplifier A1 of resistance R 79, 4 pin of operational amplifier A 6 connect negative supply, it is anodal that 6 pin meet diode D13, the parallel connected end of diode D20 negative pole, the anodal serial connection of diode D20 capacitor C 32 positive poles, capacitor C 32 negative poles connect negative supply, connect after diode D13 negative pole series resistor R90 and measure the resistance R 89 of switching with computing circuit (4), the parallel connected end of adjustable resistance RP9, 7 pin connect the adjustable side of adjustable resistance RP10, No. 5 lead-in wires of junction plate key after serial connection R40,
1 of dual operational amplifier A1, contact after 2 pin short circuits between connecting resistance R75 serial connection capacitor C 35, the other end connecting resistance R74 of resistance R 75, the parallel connected end of capacitor C 34, 3 pin of another termination dual operational amplifier A2 of resistance R 74, the parallel connected end of capacitor C 36, the other end connecting resistance R65 of capacitor C 36, the parallel connected end of the other end of capacitor C 35, another termination capacitor C 34 of resistance R 65, contact between the other end connecting resistance R75 series resistor R74 of capacitor C 34, 3 pin of dual operational amplifier A1 meet measuring voltage input end P1, the parallel connected end of resistance R 50, another termination of resistance R 50 is measured 5 pin of the four high guaily unit IC5 of switching and computing circuit (4), the parallel connected end of resistance R 86, 4 pin of dual operational amplifier A1 connect negative supply, 6, connect the resistance R 78 of current amplification circuit (2) after 7 pin short circuits, the parallel connected end of capacitor C 37, 8 pin of 8 pin and dual operational amplifier A2 and to connect the voltage stabilizing diode D21 of filtering circuit (5) anodal.
5. a kind of automatic measurement grounded screen impedance means according to claim 1 is characterized in that described measurement switching and computing circuit (4) are:
5 pin skies of operational amplifier A 7 connect, 1 pin series resistor R59, adjustable resistance RP4, resistance R 60 connects 8 pin, 2 pin connecting resistance R63, capacitor C 40, the parallel connected end of resistance R 64,1 pin of another relay termination J1 of resistance R 63, the resistance R 30 of 45Hz/55Hz alien frequencies constant-current source circuit (1), resistance R 64, 6 pin of another termination operational amplifier A 7 of capacitor C 40 parallel connections, but an end and the adjustable side thereof of adjustable resistance RP8, the parallel connected end of resistance R 58,2 pin of another relay termination J1 of resistance R 58, the parallel connected end of resistance R 61, another termination capacitor C 42 of resistance R 61, the resistance R 34 of 45Hz/55Hz alien frequencies constant-current source circuit (1), measuring current output terminal C2, the resistance R 70 of current amplification circuit (2), resistance R 76, resistance R 4, the parallel connected end of capacitor C 39,3 pin of another relay termination J1 of adjustable resistance RP8,3 pin connecting resistance R62 of operational amplifier A 7, the parallel connected end of capacitor C 27,2 of four path analoging switch IC1 of another termination 45Hz/55Hz alien frequencies constant-current source circuit (1) of resistance R 62, 3 pin, 4 pin of another termination operational amplifier A 7 of capacitor C 27,4 pin of operational amplifier A 7 connect negative supply, but 7 pin of operational amplifier A 7 connect the adjustable side of adjustable resistance RP4, 7 pin of operational amplifier A 8 etc. are connected in series No. 5 lead-in wires of junction plate key after R40 together,
5 pin skies of operational amplifier A 8 connect, 1 pin series resistor R55, adjustable resistance RP3, resistance R 56 connects 8 pin, 2 pin connecting resistance R57, the parallel connected end of capacitor C 41, the other end connecting resistance R46 of resistance R 57, capacitor C 28, the parallel connected end of resistance R 54, resistance R 54, the other end of capacitor C 41 also connects 6 pin of operational amplifier A 8, the end of resistance R OUT, the collector of the triode T7 of another termination 45Hz/55Hz alien frequencies constant-current source circuit (1) of resistance R OUT, 2 pin of relay J 4, 1 pin of another relay termination J1 of resistance R 46, connect A/D change-over circuit and microcomputer system (6) after 3 pin series resistor R47 of operational amplifier A 8, the other end of capacitor C 28, the emitter of the triode T11 of 45Hz/55Hz alien frequencies constant-current source circuit (1), the collector of triode T12, the parallel connected end of resistance R 10, 4 pin of operational amplifier A 8 connect negative supply, but 7 pin connect the adjustable side of adjustable resistance RP3, No. 5 lead-in wires of junction plate key after serial connection R40,
1 pin of four high guaily unit IC5 connects 4 pin of the operational amplifier A 9 of filtering circuit (5), 7 pin of operational amplifier A 10 connect 10 pin after the 2 pin series resistor R38 of four high guaily unit IC5, and 10 pin series resistor R37 connect 8 pin, and it is anodal that 8 pin meet diode D17, and diode D17 negative pole connects 6 pin of four XOR gate IC6, series resistor R48 connects 7 pin of four XOR gate IC6, capacitor C 20 positive poles, the parallel connected end of resistance R 45, the 3 pin connecting resistance R85 of four high guaily unit IC5, the parallel connected end of R84, the other end connecting resistance R27 of resistance R 85, capacitor C 14, the parallel connected end of diode D15, contact between resistance R 95 serial connection R39, another termination negative supply of resistance R 84,4 of four high guaily unit IC5, serial connection capacitor C 24 between 11 pin, No. 5 lead-in wires of junction plate key after the 4 pin serial connection R40 of four high guaily unit IC5, resistance R 15, the parallel connected end of resistance R 14,13 pin of another termination four XOR gate IC6 of resistance R 15, series resistor R12 succeeds 1 pin of electrical equipment J2,1 pin of another termination four XOR gate IC6 of resistance R 14, succeed 7 pin of electrical equipment J1 after series resistor R11, the 5 pin connecting resistance R50 of four high guaily unit IC5, the parallel connected end of resistance R 86, another termination measuring voltage input end P1 of resistance R 50,6 pin of another relay termination J4 of resistance R 86, the 6 pin series resistor R87 of four high guaily unit IC5 connect 7 pin, the end of 7 pin connecting resistance R88, but connect the resistance R 90 of voltage amplifier (3) behind the other end of resistance R 88 serial connection adjustable resistance RP9 and adjustable side thereof, succeed 3 pin of electrical equipment J4 after the other end series resistor R89 of adjustable resistance RP9, contact between the anodal serial connection capacitor C of capacitor C 87 negative poles of filtering circuit (5), capacitor C 4, capacitor C 1, the parallel connected end of the resistance R 91 of voltage amplifier (3), the 9 pin connecting resistance R35 of four high guaily unit IC5, be connected in series No. 5 lead-in wires of junction plate key after R40 together with the parallel connected end of R36,7 pin of the other end of resistance R 35 and operational amplifier A 8 etc., another termination negative supply of resistance R 36, the 12 pin connecting resistance R19 of four high guaily unit IC5, the parallel connected end of resistance R 20, capacitor C 7 positive poles of another termination filtering circuit (5) of resistance R 19, telefault U1, by diode D7, D8, D9, the positive output end of the bridge rectifier that D10 forms, another termination negative supply of resistance R 20,13 of four high guaily unit IC5, 14 pin short circuits,
the 4 pin skies of four XOR gate IC6 connect, 1 pin connecting resistance R14, the parallel connected end of resistance R 11, the other end connecting resistance R15 of resistance R 14, No. 5 lead-in wires of junction plate key after serial connection R40,7 pin of another relay termination J1 of resistance R 11,2 of four XOR gate IC6, 5, 9, connect A/D change-over circuit and microcomputer system (6) after 12 pin short circuits, 3 of four XOR gate IC6, 10, 11 pin connect respectively 28 of display (7), 36, 32 pin, the 6 pin connecting resistance R48 of four XOR gate IC6, the parallel connected end of diode D17 negative pole, 7 pin of another termination four XOR gate IC6 of resistance R 48, capacitor C 20 positive poles, resistance R 45, the parallel connected end of A/D change-over circuit and microcomputer system (6), 1 pin of another relay termination J4 of resistance R 45, the negative pole of capacitor C 20 connects negative supply, the 8 pin connecting resistance R16 of four XOR gate IC6, the parallel connected end of R13,1 pin of another relay termination J3 of resistance R 13,2 pin of another termination JK1 of resistance R 16, C3 is anodal, the parallel connected end of A/D change-over circuit and microcomputer system (6), the 13 pin connecting resistance R15 of four XOR gate IC6, the parallel connected end of resistance R 12, No. 5 of junction plate key lead-in wires after the other end connecting resistance R14 series resistor R40 of resistance R 15,1 pin of another relay termination J2 of resistance R 12, the 14 pin connecting resistance R9 of four XOR gate IC6, resistance R 39, the parallel connected end of capacitor C 33,16 pin of the trigger IC7 of another termination filtering circuit (5) of resistance R 9, the capacitor C 9 of 45Hz/55Hz alien frequencies constant-current source circuit (1), the parallel connected end of the pin of connection terminal JK1, the other end connecting resistance R85 of resistance R 39, the capacitor C 14 of 45Hz/55Hz alien frequencies constant-current circuit (1), diode D15 negative pole, resistance R 27, resistance R 31, the parallel connected end of resistance R 95, the other end serial connection adjustable resistance RP2 of resistance R 95, connect anodal contact, the regulated termination A/D change-over circuit of adjustable resistance RP2 and the microcomputer system (6) that is connected in series between capacitor C 5 negative poles of capacitor C 6 of filtering circuit (5) after resistance R 96.
6. a kind of automatic measurement grounded screen impedance means according to claim 1 is characterized in that described filtering circuit (7) is:
1 of trigger IC7, 12, 15 pin skies connect, 2 pin connecting resistance R83, the parallel connected end of light emitting diode LD1 positive pole, 5 pin connecting resistance R82, the parallel connected end of light emitting diode LD2 positive pole, 7 pin connecting resistance R81, the parallel connected end of light emitting diode LD3 positive pole, 10 pin connecting resistance R80, the parallel connected end of light emitting diode LD4 positive pole, light emitting diode LD1, LD2, LD3, after the negative pole parallel connection of LD4, series resistor R26 connects negative supply, resistance R 80, R81, R82, the other end of R83 meets respectively triode T1, T2, T3, the base stage of T4, the coil of the collector connecting relay J1 of triode T1, the parallel connected end of diode D19 positive pole, the coil of the collector connecting relay J2 of triode T2, the parallel connected end of diode D18 positive pole, the coil of the collector connecting relay J3 of triode T3, the parallel connected end of diode D16 positive pole, the coil of the collector connecting relay J4 of triode T4, the parallel connected end of diode D14 positive pole, relay J 1, J2, J3, the other end of J4 coil and diode D19, D18, D16, meet+the 9V power supply 3 of trigger IC7 after the negative pole parallel connection of D14, 4, 6, 11 pin are series diode D1 respectively, D2, D11, D12 is anodal, diode D1, D2, D11, 9 pin of contact hair device IC7 after the negative pole short circuit of D12,8 of trigger IC7, 13, meet triode T1 after 14 pin short circuits, T2, T3, the parallel connected end of T4 emitter, negative supply, resistance R 97, R98, R93, parallel end connection capacitor C 3 negative poles of R94, capacitor C 3 positive poles connect 2 pin of connection terminal JK1, measure the resistance R 16 of switching with computing circuit (4), the parallel connected end of A/D change-over circuit and microcomputer system (6), resistance R 97, R98, R93, 6 of the other end difference junction plate key of R94, 7, 8, No. 9 lead-in wires, 16 pin of trigger IC7 connect measures the resistance R 9 of switching with computing circuit (4), the parallel connected end of capacitor C 9, 3 pin of connection terminal JK1,
1,5,8 pin skies of operational amplifier A 10 connect, and 2 pin connect the collector of triode T8, and 3 pin of operational amplifier A 10 connect the parallel connected end of contact between telefault U2 serial connection capacitor C 6 negative poles of filtering circuit (5), resistance R 5, resistance R 100, another termination voltage stabilizing diode D3 of resistance R 5 is anodal, the parallel connected end of D4 negative pole, one termination negative supply of the negative pole of voltage stabilizing diode D3 and resistance R 51, 4 pin of another termination operational amplifier A 10 of resistance R 100, the parallel connected end of the positive pole of voltage stabilizing diode D4, 6 pin of operational amplifier A 10 connect the base stage of triode T8, the emitter of triode T8 meets measuring current output terminal C1, the negative pole of the voltage stabilizing diode D5 of 45Hz/55Hz alien frequencies constant-current source circuit (1), 7 pin of operational amplifier A 10 connect 4 pin of operational amplifier A 9, measure 1 pin of the four high guaily unit IC5 of switching and computing circuit (4),
1 of operational amplifier A 9, 5, 8 pin skies connect, and 2 pin connect triode T10 collector, the parallel connected end of resistance R 1, the parallel end connection voltage stabilizing diode D21 negative pole of the other end of resistance R 1 and resistance R 2, the parallel connected end of voltage stabilizing diode D22 positive pole, the positive pole of voltage stabilizing diode D21 connect 8 pin of the dual operational amplifier A1 of voltage amplifier circuit (3), 8 pin of the dual operational amplifier A2 of current amplification circuit (2), after the other end series resistor R6 of resistance R 2 with 7 pin of operational amplifier A 9, the negative pole of voltage stabilizing diode D22 meets telefault U1 together, the parallel connected end of capacitor C 5 positive poles, the diode D7 of another termination 45Hz/55Hz alien frequencies constant-current source circuit (1) of telefault U1, D8, D9, the positive output end of the bridge rectifier that D10 forms, the positive pole of capacitor C 7, measure the parallel connected end of the resistance R 19 in switching and computing circuit (4), the negative pole of capacitor C 5 connects the positive pole of capacitor C 6, measure the parallel connected end of the resistance R 96 of switching and computing circuit (4), the negative pole of capacitor C 6 meets telefault U2, 3 pin of the operational amplifier A 10 of 45Hz/55Hz alien frequencies constant-current source circuit (1), resistance R 100, the parallel connected end of resistance R 5, the negative pole of another termination capacitor C 8 of telefault U2, the diode D7 of 45Hz/55Hz alien frequencies constant-current circuit (1), D8, D9, the negative output terminal of the bridge rectifier that D10 forms, the positive pole of capacitor C 8 connects capacitor C 7 negative poles, capacitor C 4, the parallel connected end of capacitor C 1 grade, 3 pin of operational amplifier A 9 connect the collector of the triode T11 of 45Hz/55Hz alien frequencies constant-current source circuit (1), 6 pin of operational amplifier A 9 connect the base stage of triode T10 and the parallel connected end of capacitor C 2, the emitter of triode T10 connects serial connection capacitor C 1 after the other end of capacitor C 2, the other end serial connection capacitor C 4 of capacitor C 1, contact between capacitor C 7 negative pole serial connection C8 positive poles, the resistance R 91 of voltage amplifier circuit (3), measure the resistance R 89 of switching with computing circuit (4), the parallel connected end of 3 pin of relay J 4, the triode T9 base stage of another termination 45Hz/55Hz alien frequencies constant-current source circuit (1) of capacitor C 4 and the parallel connected end of diode D6 negative pole, capacitor C 7 positive poles meet telefault U1, diode D7, D8, D9, the positive output end of the bridge rectifier that D10 forms, measure the parallel connected end of the resistance R 19 of switching and computing circuit (4).
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| CN 201220663731 CN202975161U (en) | 2012-12-06 | 2012-12-06 | Device for automatically measuring impedance of grounding grid |
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| CN 201220663731 CN202975161U (en) | 2012-12-06 | 2012-12-06 | Device for automatically measuring impedance of grounding grid |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104079068A (en) * | 2014-06-04 | 2014-10-01 | 国家电网公司 | Pilot frequency generation circuit for testing secondary circuit impedance with pilot frequency admittance method |
| CN106645860A (en) * | 2017-01-11 | 2017-05-10 | 国家电网公司 | Transformer station grounding device characteristic parameter detection verification system |
| CN107192885A (en) * | 2017-05-18 | 2017-09-22 | 四川中鼎科技有限公司 | Using alien frequencies, the method for high-current test large hydropower station Grounding impedance |
| CN113777595A (en) * | 2021-09-14 | 2021-12-10 | 天津理工大学 | Ultrasonic receiving circuit |
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2012
- 2012-12-06 CN CN 201220663731 patent/CN202975161U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104079068A (en) * | 2014-06-04 | 2014-10-01 | 国家电网公司 | Pilot frequency generation circuit for testing secondary circuit impedance with pilot frequency admittance method |
| CN106645860A (en) * | 2017-01-11 | 2017-05-10 | 国家电网公司 | Transformer station grounding device characteristic parameter detection verification system |
| CN106645860B (en) * | 2017-01-11 | 2019-04-02 | 国家电网公司 | Substation grounding equipment energy characteristic parameter detecting check system |
| CN107192885A (en) * | 2017-05-18 | 2017-09-22 | 四川中鼎科技有限公司 | Using alien frequencies, the method for high-current test large hydropower station Grounding impedance |
| CN113777595A (en) * | 2021-09-14 | 2021-12-10 | 天津理工大学 | Ultrasonic receiving circuit |
| CN113777595B (en) * | 2021-09-14 | 2023-08-11 | 天津理工大学 | Ultrasonic wave receiving circuit |
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