CN2166460Y

CN2166460Y - Computerized high-voltage insulation resistance tester

Info

Publication number: CN2166460Y
Application number: CN 93223678
Authority: CN
Inventors: 施亚民
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-09-02
Filing date: 1993-09-02
Publication date: 1994-05-25
Anticipated expiration: 2003-09-02

Abstract

The utility model relates to a computerized high-voltage insulation resistance tester, which is characterized in that the test circuit is provided with a computer 7 which automatically corrects and processes data, wherein, computer counting ports T0, T1 are respectively electrically isolated from and in a signaling way communicated with output ends Fv, Fi of V/F converters 14, 16 of a sample circuit through a light coupled unit 6; the display output end Px is connected with a display 8; a control end Po is connected with a high-voltage throw cut switch 10 of an inverting power supply; control ends P1 and P2-P5 are respectively electrically isolated from and in a signaling way communicated with pressure input selection switches DK1, DK2 of the sample circuit, current input selection switches DK3, DK4 of the sample circuit and amplification control switches DK5, DK6 through the light coupled unit.

Description

Computerized high-voltage insulation resistance tester

The utility model relates to a kind of measurement instrument, particularly a kind of high-voltage insulating resistance analyzer that is used for electrical equipment.

The existing measuring instrument that is used for high-voltage insulating resistance, pointer-type and digital two kinds of fundamental types are roughly arranged, the digital automatic range insulation resistance meter of Chinese patent CN2116223V is more typically arranged, because this class instrument is non intelligent type measuring instrument, can not realize automatic calibration and data processing, thereby can not keep long-term measuring accuracy, be difficult to keep long-term stability and accuracy.On the other hand, above-mentioned instrument can not carry out automatic switching to high-voltage power supply, and the power consumption of working power is bigger, influences the working service of instrument.

The purpose of this utility model is to provide a kind of long-time stability good, the microcomputer type high-voltage insulating resistance analyzer that measuring accuracy height and working power power consumption are little.

In order to achieve the above object, this programme has set in the metering circuit of instrument and has been used for measuring-signal is carried out microcomputer from normal moveout correction and data processing, and can carry out automatic switching to high-voltage power supply.The metering circuit of this programme mainly comprises inverter, sample circuit, photo-coupler group and microsystem.Inverter is in order to be upgraded to dc high voltage with DC low-voltage, as the high-tension measurement source of instrument; Sample circuit comprises voltage sample and current sample two parts, the former can gather the amplitude of high-tension measurement power supply, the latter crosses the current amplitude of measured resistance in order to acquisition stream, and two sampling circuits export the counting mouth of microcomputer respectively to by the V/F transducer, by drawing the measured resistance value after the MICROCOMPUTER PROCESSING; The output control terminal of microcomputer is done electricity isolation and signal communication with sample circuit respectively by the photo-coupler group, and its high-voltage power supply control end is connected with display with the high pressure fling-cut switch of inverter respectively with the demonstration output terminal.This programme is the zero offset capability of realizing in the following manner measuring-signal: at first, output password voltage and current sampling circuit by microcomputer is imported same correction signal, and with the ratio internal memory of the output valve of the V/F transducer of two sampling circuits, electric current when making two sampling circuit roads then, the terminal voltage of current sampling resistor RI is proportional to the electric current I X that flows through measured resistance RX, therefore, as long as record the value that the terminal voltage of RV1 and RV2 just can be measured the value of VH and IX and then can measure measured resistance RX.In order to improve measuring accuracy, sample circuit is positioned at the high-pressure side of instrument, microsystem then is positioned at the low-pressure side of instrument, and both do through the photo-coupler group, and electricity is isolated and the signal communication, and the voltage follower in the sample circuit is used to improve the input impedance of voltage signal input circuit; The V/F transducer converts input direct voltage to the correspondent frequency signal is coupled to microcomputer through the photo-coupler group counting mouth T0 and T1.The output control terminal P1 of microcomputer and～P2-P5 is respectively through the voltage input selector switch DK1 of photo-coupler group and sample circuit, DK2, with electric current input selector switch DK3, DK4 and amplifier gauge tap DK5, DK6 connects, the high-voltage power supply control end P0 of microcomputer is connected with the high pressure fling-cut switch 10 of inverter, and it shows that output terminal PX is connected with display 8.In this enforcement, high pressure fling-cut switch 10 is made of reverser, compound transistor and current limliting electricity group, and high pressure generator 11 is made of electronics inversion boosting device 17, voltage doubling rectifing circuit 18; Insulating power supply 12 is by electronic inverter 19, and commutating circuit 20, positive mu balanced circuit 21 and negative mu balanced circuit 22 are formed.The working power UD and the Us of sample circuit are provided by insulating power supply, the output terminal of insulating power supply and the noble potential of high pressure generator output C end equipotential, and the C point is again the electric common point of sample circuit, its potential difference (PD) to the electric common port of microcomputer is UH.The enlargement factor of current sampling circuit amplifier is by the ratio decision of resistance R 3 with R4, R5 provides input deviator electric current for amplifier, follower 23 constitutes the signal damping circuit and plays the impedance conversion effect, DK1-DK6 is an electronic analog swtich, handled by microcomputer output control terminal P1-P5, the high pressure generator of present embodiment and insulating power supply are transistor inverse power supply, positive voltage stabilizing and negative mu balanced circuit all adopt the output of three-terminal voltage-stabilizing integrated package, working power is selected dry cell batteries for use, and display is a crystal digital coding on the display; The V/F transducer is selected the LM331 type for use, and microcomputer is a 87C51 type single-chip microcomputer.

Principle of work of the present utility model is: when instrument is brought into use, it is high level that microcomputer is at first put the P2 mouth, all the other delivery outlets are low level, at this moment, high pressure generator cuts out, photo-coupler group output port K4 is a high level, and K4 makes DK2 and DK4 simultaneously and makes its conducting simultaneously, follows the ratio of output valve that switches to the working position and record their V/F transducer once more; As long as front and back record for twice ratio be divided by can the modifying factor sample circuit the characteristic instability and the error that causes draws the measured resistance resistance at last.Feature of the present utility model is the microcomputer of the carrying out that does not cooperate with inverter, sample circuit and display from normal moveout correction and data processing, the counting of this microcomputer is done electricity isolation and signal communication with the output terminal of sample circuit V/F transducer respectively through the photo-coupler group, it shows that defeated end is connected with the fling-cut switch of inverter, and its output control terminal is respectively through the voltage input selector switch and the electric current input selector switch of photo-coupler group and sample circuit and the amplifier gauge tap is done electric isolation and signal is communicated.

The utility model has the advantages that since realized to measuring-signal from normal moveout correction and data processing function, instrument is maintained a long-term stability accurately works, improved the measuring accuracy of instrument effectively, and realized intelligent measuring, this surveying instrument also can carry out automatic switching to high-voltage power supply, save the consumption of working power greatly, had good practical values.

Below, will be further described the utility model with accompanying drawing in conjunction with the embodiments.

Fig. 1 is a contour structures synoptic diagram of the present utility model.

Fig. 2, Fig. 3 are circuit block diagram.

Fig. 4 is the sample circuit schematic diagram.

With reference to Fig. 1--Fig. 4: the utility model comprises housing 1, power switch 2, start button 3 and is positioned at measuring junction L, the N of shell face, and L is the high-tension measurement end, and N is an earth terminal.The metering circuit of this programme comprises that inverter 4, sample circuit 5, photo-coupler group 6, microsystem 7, display 8 and working power 9, inverter be made up of high pressure fling-cut switch 10, high pressure generator 11 and insulating power supply 12; Voltage sample loop that sample circuit is made up of voltage sample resistance R V1, dropping resistor RV2, voltage follower 13, V/F transducer 14 and the current sampling circuit of forming by current sampling resistor RI, current-limiting resistance RN, amplifier 15 and V/F transducer 16.At the exportable direct current voltage VH of foregoing circuit mesohigh generator; RV1 and RV2 constitute an accurate voltage divider; Current-limiting resistance RN is used to place restrictions on the correction signal for the voltage divider generation is made up of resistance R 1, R2 of high-tension measurement end L and short device 13 of earth terminal N and 23 inputs, this moment, microcomputer recorded voltage sample loop and two ratios by the frequency signal of V/F transducer output of current sampling circuit, and with its internal memory.After this microcomputer makes that high-voltage power supply control end P0 is a high level, to open high pressure generator, with seasonal P2 is low level, P1, P3 is a high level, correspondingly photo-coupler group output K4 is a low level, K1, K3 is a high level, K5 is a low level, electronic switch DK1 and DK3 conducting, all the other all disconnect, at this moment, the voltage signal for being directly proportional of follower 13 inputs with high pressure UH, the measuring-signal for being directly proportional of 23 inputs with IX, microcomputer is sampled to the frequency signal of V/F transducer 16 outputs earlier, if this value is greater than setting value, microcomputer is promptly sampled to the output signal of transducer 14, draw the ratio of two signals that is the resistance of measured resistance then, if the signal of transducer 16 output is less than setting value, even microcomputer P3 mouth is a low level, P4, the P5 mouth is a high level, corresponding photo-coupler group output terminal K3 is a low level, K5, K6 is a high level, and electronic switch DK3 disconnects, DK5, the DK6 conducting, the output signal for having amplified several times through amplifier of follower 23 inputs, this moment, the measured resistance value also correspondingly increased several times.Microcomputer is got a sample go forward side by side row operation and demonstration to two signals at regular intervals.When the resistance of the operation result of sampling several times continuously is constant, microcomputer promptly put the P0 mouth be low level to close high pressure generator and to send the measurement end signal, display shows last measured value up to shutdown, at this moment, one-shot measurement finishes.The input of above-mentioned high pressure generator is to realize like this with disconnection, reverser is output as low level when the P0 of microcomputer mouth is high level, compound transistor BG conducting, high pressure generator input power connection, high pressure generator is devoted oneself to work, then close when the P0 mouth is low level, R6 is the base stage current-limiting resistance of BG.

Claims

1, a kind of microcomputer type high-voltage insulating resistance analyzer, comprise housing (1) and by inverter (4), sample circuit (5), display (8), the peripheral circuit that working power (9) is formed, it is characterized in that being provided with the carrying out that cooperate with foregoing circuit microcomputer (7) from normal moveout correction and data processing, the counting pin T0 of this microcomputer, T1 through the photo-coupler group respectively with the V/F transducer (14) of sample circuit, (16) output terminal Fv, Fi does electricity isolation and signal communication, show that output terminal Px is connected with display, high-voltage power supply control P0 is connected with the high pressure fling-cut switch (10) of inverter, and control end P1 and P2-P5 are respectively through the voltage input selector switch DK1 of photo-coupler group and sample circuit, DK2 and electric current input selector switch DK3, DK4 and amplifier gauge tap DK5, DK6 does electricity isolation and signal communication.