CN101196492A - Method for detecting leakage of constant voltage discharging type sulfur hexafluoride - Google Patents

Abstract

The invention relates to a constant voltage and dielectricsulphur hexafluoride air leakage testing method. The used device in the method is composed of a singlechip, an adjustable high-voltage module, a dielectric electrode, a voltage measuring circuit, an electric current measuring circuit and a communication module. The two I/O interfaces of the singlechip are connected with the On/Off end of the adjustable high-voltage module and the PWM controlling end; the output end of the adjustable high-voltage module is connected with one end of the dielectric electrode, and simultaneously connected in series to the voltage measuring circuit, while the other end of the dielectric electrode is connected with the electric current measuring circuit; the eclectic current is converted into voltage and sent into the ADC end of the single chip by the voltage measuring circuit and the electric current measuring circuit; one end of the communication module is connected with a host computer, the other end is connected with the singlechip. The singlechip generates a signal drive high-voltage module, which makes the dielectric electrode in the dielectric situation and then gradually reduces the dutyfactor of PWM signal. The invention overcomes the defect that the traditional NIC testing method is easy affected by environment, which improves the practicality of NIC method.

Description

A kind of detection method of leakage of constant voltage discharging type sulfur hexafluoride

Technical field

The present invention relates to the detection method that a kind of sulfur hexafluoride gas leaks, particularly a kind of sulfur hexafluoride gas micro-leakage detection method that adopts constant voltage discharging type.

Background technology

Sulfur hexafluoride (SF ₆) gas is colourless, tasteless, proportion is bigger than air, has good arc extinguishing and insulating property, is widely used in the power equipment of high voltage substation.SF in power equipment ₆Gas leaks, and its arc extinguishing and insulating capacity reduce, and the safe operation of power equipment can not get guaranteeing, will produce great accident of power supply when serious.China's " electrical safe working order " special provision must be installed SF in relevant place ₆The detection alarm device.

Detect SF at present ₆The gas major technique has: spectral analysis technique, negative ion are caught Detection Techniques, negative corona discharge Detection Techniques (NIC) etc., preceding two kinds of methods have the accuracy of detection height, the advantage of stable performance, but its detection technique complexity, equipment is huge, cost is high, is not suitable for online detection long-time, regional environment; The NIC detection technique is to utilize two discharge currents between the high-field electrode with airborne SF ₆Gas concentration is different and change, and by detecting the size of this electric current, can fast detecting go out SF ₆Whether gas leaks.The NIC detection technique is having bigger advantage on the cost and in the technology realization, but the discharge current of high-field electrode is subject to environment temperature and humidity effect, and discharging efficiency reduces with the prolongation of working time, occur easily because the warning message that discharge leads to errors unusually, cause detecting the with a low credibility of leakage, seriously influence the actual application value of this technology.Therefore, how to overcome the unstable and easily aging problem of flash-over characteristic of high-field electrode, improve the practicality of NIC detection technique, be the focus and research difficult point of this type systematic always.

Summary of the invention

In order to overcome NIC technology flash-over characteristic problem of unstable, improve the confidence level of sulfur hexafluoride gas Leak Detection, the invention provides a kind of sulfur hexafluoride gas micro-leakage detection method of constant voltage discharging type, can address the above problem effectively, reduce the influence of environmental factor discharge current.

For realizing that the technical scheme that target of the present invention adopts is: at first build the online leakage detection apparatus of sulfur hexafluoride gas, this device is made up of single-chip microcomputer (MCU), adjustable high-pressure modular, sparking electrode, tension measuring circuit, current measurement circuit and communication module.Single-chip microcomputer links to each other with adjustable high-pressure modular, tension measuring circuit, current measurement circuit and communication module respectively, and adjustable high-pressure modular, tension measuring circuit, current measurement circuit and sparking electrode link to each other.Wherein: single-chip microcomputer and high-pressure modular are connected with two I/O mouths, and one is ON/OFF, are used to control the unlatching of high-pressure modular or close, and one is PWM, and the I/O mouth is exported in the special-purpose width modulation of single-chip microcomputer, is used to control the output high-voltage value of high-pressure modular; One end of the output termination sparking electrode of adjustable high-pressure modular, be parallel-connected to tension measuring circuit simultaneously, another has the termination current measurement circuit sparking electrode; Tension measuring circuit, current measurement circuit are converted to the ADC input end that voltage exports single-chip microcomputer to input current.Communication module one termination host computer, the other end links to each other with single-chip microcomputer.

The voltage adjusting range of described adjustable high-pressure modular is between 1000V～2000V.

The Standard resistance range of resistance R 1 is 1M Ω～2M Ω in the described tension measuring circuit.

The Standard resistance range of resistance R 2 is 10K Ω～100K Ω in the described current measurement circuit.

Detection method realizes by following steps: 1. produce pwm signal by single-chip microcomputer and drive high-voltage power module, control the size of its output voltage, monitor the discharge current of sparking electrode simultaneously.2. increase the dutycycle of pwm signal gradually, high pressure is grown steadily, when the discharge current that monitors reaches certain value, illustrate that sparking electrode has been in discharge condition.3. reduce the dutycycle of pwm signal gradually, high pressure descended steadily, when high pressure drops to the constant voltage scale value of setting, measure the discharge current of this moment, according to the size of this electric current as judging SF ₆The foundation whether gas leaks

The invention has the beneficial effects as follows: solved the deficiency that traditional NIC detection method is subject to the influence of environment degree, improved sulfur hexafluoride gas effectively and leak the accuracy of judgement and the practicality of NIC detection method.

Accompanying drawing and description of drawings

Fig. 1 is a circuit design drawing of the present invention.

Fig. 2 is the detection method process flow diagram among the present invention.

Fig. 3 is the circuit theory diagrams of an application example of the present invention.

Among Fig. 1, single-chip microcomputer (1) is connected with two I/O mouths with high-pressure modular, and one is ON/OFF, uses In control high-pressure modular unlatching or close; One is PWM, and the special-purpose pulsewidth modulation of single-chip microcomputer (1) is defeated Go out the I/O mouth, be used for the output high-voltage value of control high-pressure modular. The output termination of adjustable height die block (3) is put One end of electricity electrode (6), be parallel-connected to tension measuring circuit (3) simultaneously, sparking electrode (6) another Termination current measurement circuit (4) is arranged. Tension measuring circuit (3), current measurement circuit (4) are with input current Be converted to Voltage-output to the ADC input of single-chip microcomputer (1). Communication module (5) one termination host computers, The other end links to each other with single-chip microcomputer (1).

Among Fig. 2, at first start one-shot measurement, control PWM output thereupon, progressively control the adjustable height die block Boosted output voltages; Detect and to judge whether High voltage output surpasses the maximum of setting, if surpass, then this Measuring process finishes. If do not surpass, then carry out discharge current and measure, whether locate to judge sparking electrode In discharge condition. If this moment is not discharge also, then control again PWM output, control adjustable height die block Boosted output voltages; If discharge, then control PWM output, make High voltage output be stabilized to the constant voltage of setting, And after a period of stabilisation, can carry out the measurement of discharge current size.

Among Fig. 3, the pin 1,2,3 of single-chip microcomputer (U2) respectively with the pin of adjustable height die block (U1) 3,4,5 link to each other, and pin 4 is connected with resistance R, the pin 1 of capacitor C 3, sparking electrode (U3) connects, and draws Pin 11 links to each other with GND, and an other end of capacitor C 3 links to each other with ground. Two of adjustable height die block (U1) Individual power pins 1,2 is connected respectively to+12V and GND, and pin 6 (HV) links to each other electricity with resistance R 1 The other end of resistance R1 and the pin 2 of sparking electrode (U3) link to each other. One end of capacitor C 1 with+12V mutually Connect, an other end links to each other with ground GND.

Embodiment:

For the ease of the present invention is further understood, existing circuit theory diagrams in conjunction with the described circuit design drawing of figure, detection method flow process, application example are done detailed process and are described.

Embodiment 1

Implement according to the described circuit design drawing of Fig. 1.

Connect according to the described circuit theory diagrams of Fig. 3.

Detection method may further comprise the steps:

Step 201: start the one-shot measurement process.

Step 202: control PWM output, progressively control adjustable high-pressure modular boosted output voltages.

Step 203: detect to judge this moment, whether high pressure output surpassed the maximal value of setting, if surpass, trip step 207 then, otherwise execution in step 204.

Step 204: measure discharge current, whether be in discharge condition to judge sparking electrode, if also not discharge, then execution in step 202, continue boosted voltage, if discharge, then execution in step 205.

Step 205: control PWM output makes high pressure output be stabilized to the constant voltage of setting.

Step 206: stablize a period of time, measure the discharge current size.

Step 207: this measuring process finishes.

Claims (6)

1. the detection method of a leakage of constant voltage discharging type sulfur hexafluoride is characterized in that:

1) forms pick-up unit by single-chip microcomputer, adjustable high-pressure modular, tension measuring circuit, current measurement circuit, communication module and sparking electrode, single-chip microcomputer links to each other with adjustable high-pressure modular, tension measuring circuit, current measurement circuit and communication module respectively, and adjustable high-pressure modular, tension measuring circuit, current measurement circuit and sparking electrode link to each other;

2) single-chip microcomputer produces pwm signal and drives high-voltage power module, increase the dutycycle of pwm signal gradually, make sparking electrode be in discharge condition, then reduce the dutycycle of pwm signal gradually, the high-voltage value of a setting of adjustable high-pressure modular output is measured the discharge current of this moment.

2. according to the detection method of the described leakage of constant voltage discharging type sulfur hexafluoride of claim 1, it is characterized in that: two I/O mouths of single-chip microcomputer are connected to On/Off end, the PWM control end of adjustable high-pressure modular; One end of the output termination sparking electrode of adjustable high-pressure modular, be parallel-connected to tension measuring circuit simultaneously, another has the termination current measurement circuit sparking electrode; Tension measuring circuit, current measurement circuit are converted to the ADC input end that voltage exports single-chip microcomputer to input current; Communication module one termination host computer, the other end links to each other with single-chip microcomputer.

3. according to the described monitoring device of claim 1, it is characterized in that: the voltage adjusting range of adjustable high-pressure modular is between 1000V～2000V.

4. according to the detection method of the described leakage of constant voltage discharging type sulfur hexafluoride of claim 1, the Standard resistance range that it is characterized in that the resistance R 1 in the described embodiment voltage measurement schematic circuit is 1M Ω～2M Ω.

5. according to the detection method of the described leakage of constant voltage discharging type sulfur hexafluoride of claim 1, the Standard resistance range that it is characterized in that the resistance R 2 in the described embodiment current measurement schematic circuit is 10K Ω～100K Ω.

6. according to the detection method of the described leakage of constant voltage discharging type sulfur hexafluoride of claim 1, it is characterized in that detection method may further comprise the steps:

Step 201: start the one-shot measurement process.

Step 202: control PWM output, progressively control adjustable high-pressure modular boosted output voltages.

Step 203: detect and judge this moment, whether high pressure output surpassed the maximal value of setting, if surpass, then execution in step 207, otherwise execution in step 204.

Step 204: measure discharge current, whether be in discharge condition to judge sparking electrode, if also not discharge, then execution in step 202, continue boosted voltage, if discharge, then execution in step 205.

Step 205: control PWM output makes high pressure output be stabilized to the constant voltage of setting.

Step 206: stablize a period of time, measure the discharge current size.

Step 207: this measuring process finishes.

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