CN101968459B - Detection method of internal faults of switch cabinet - Google Patents

Abstract

A detection method and a detection device for an internal fault of a switch cabinet belong to the field of power transformation and distribution. For the switchgear running with electricity when the cabinet door is closed, the through hole of the switchgear body is used to extract the gas in the inner space of the cabinet outside the cabinet; through the extraction, measurement and Data comparison, comparing each unbalanced voltage value representing a certain characteristic gas concentration item with the unbalanced voltage value representing the characteristic gas concentration item of the ambient air and/or other switchgear positions, so as to detect the switchgear early Internal accidents in the initial stage or hidden dangers of early accidents, to prevent the expansion or further spread of accidents. It adopts the same gas collection method, which can sensitively detect the common operating faults of the switchgear in the cabinet. It does not need to shut down the running switchgear during work, and does not need to make changes to the existing switchgear equipment. The implementation cost is low, and it is not necessary affect the normal operation of existing equipment.

Description

A detection method for internal faults of switchgear

technical field

The invention belongs to the field of power transformation and distribution, and in particular relates to a fault detection method for electric energy transmission/distribution equipment.

Background technique

With the rapid development of my country's economy, the basic electric power industry has also achieved long-term and rapid development. As one of the important equipment in electric power construction, the application of enclosed combined electrical appliances is becoming more and more popular, and at the same time, higher requirements are put forward for the safe/stable operation of enclosed combined electrical equipment.

Air-insulated switchgear is a kind of closed combination electrical appliances, which are widely used in 10~40.5KV switchgear.

However, due to the characteristics of its closed box structure, the air-insulated switchgear also has certain shortcomings, mainly because it is difficult to find the internal electrical abnormality in the early stage. If it cannot be found and dealt with in time, it will usually cause damage/burning of the switchgear and its accessory parts, and even affect the operation of the entire system and the safety of personnel/equipment of the entire substation/substation in severe cases.

Specifically, the air-insulated switchgear generally adopts a box-type structure, which places all the components of the power distribution equipment inside the cabinet. The problem brought about by this structural form is that it is impossible to know the inside of the cabinet in a timely/intuitive manner from the outside of the cabinet The operating status of the equipment (the cabinet door is closed during normal live operation), the most common faults of the primary equipment, such as joint heating, sulfur hexafluoride gas leakage, and partial discharge abnormalities, cannot be intuitive and obvious outside the cabinet. It is discovered or manifested in a timely manner, and when it is discovered, it has often led to serious consequences.

For example, for the leakage fault of sulfur hexafluoride insulating gas, only when the pressure is lower than the alarm or blocking value, can it be indirectly displayed through the optical plate and indicator light; and for the partial discharge fault, although the high-frequency ultrasonic detection method can be used detection, but the accuracy and sensitivity of the detection are not satisfactory; another example, for joint heating faults, there is currently no good online detection method other than opening the cabinet door and using direct aiming non-contact infrared measurement; Although some units have developed a detection device and measurement method that installs temperature detectors on the contacts of switch cabinets, circuit breakers, trolleys, etc., and transmits temperature signals wirelessly, the shortcomings of this device are also obvious, and the equipment must be installed one by one. Power outages, high installation costs, and since the substations/stations are all areas of strong electromagnetic interference, there are also problems with the reliability and life of the device itself.

Therefore, how to obtain the operating status of the switchgear in the cabinet or find out its abnormal operation information in a timely and low-cost manner when the closed combination switchgear is running with electricity (at this time, the door of the switchgear is in the closed position) has become a field operation/ An urgent problem to be solved in the inspection work.

Contents of the invention

The technical problem to be solved by the present invention is to provide a detection method for internal faults of the switchgear, which adopts a non-contact gas collection method with the electrified body of the primary and secondary circuits when the switchgear is running under live conditions, which can be sensitive The common operating faults of the switchgear in the cabinet can be detected accurately, and it is not necessary to stop the running switchgear during work, and it is not necessary to modify the electrical primary and secondary circuit equipment of the existing switchgear. The implementation cost is low and does not affect The normal operation of existing equipment.

The technical solution of the present invention is to provide a detection method for internal faults of the switchgear, including the cabinet body of the switchgear, which is characterized by:

For the switchgear with live operation with the cabinet door closed, use the through hole of the switchgear body outside the cabinet body to extract the gas in the inner space of the cabinet body;

For the extracted gas in the cabinet, use a gas concentration measuring device to measure the concentration of a specified characteristic gas;

The gas concentration measuring device is provided with multiple gas sensor modules, each gas sensor module is corresponding to measure the concentration of a certain specified characteristic gas, and each gas sensor module is provided with a balance bridge;

The gas sensor module converts the concentrations of various specified characteristic gases into electrical signals;

Use the method of measuring the unbalanced voltage of each balanced bridge separately or sequentially, and reflect the concentration or concentration change trend of a certain characteristic gas in the cabinet through the value or change of the unbalanced voltage value;

Record the unbalanced voltage measurement values corresponding to various specified characteristic gas concentrations in the cabinet by the gas concentration measuring device and the unbalanced voltage measurement values corresponding to the concentration of the same specified characteristic gas in the ambient air during this period;

The unbalanced voltage measurement value of various specified characteristic gases measured in the same cabinet in a certain period of time is compared with the unbalanced voltage measurement value corresponding to the same specified characteristic gas in the ambient air and/or other different cabinets in the same period of time Compare the measured values of the unbalanced voltage corresponding to the same specified characteristic gas;

Switchgear where abnormal changes in unbalanced voltage measurements are found;

According to the type of specified characteristic gas corresponding to the abnormal change of the unbalanced voltage measurement value, the corresponding accident type and the corresponding switchgear position are correspondingly obtained;

Through the extraction, measurement/analysis and data comparison of the gas in the inner space of the cabinet under the live running state, the unbalanced voltage value representing a certain characteristic gas concentration item is compared with the ambient air and/or other switchgear positions. Comparing the unbalanced voltage values of the three characteristic gas concentration items, it shows that there are abnormal switchgear equipment positions inside.

Specifically, the above-mentioned designated characteristic gases include at least ozone, sulfur hexafluoride and smog, and the corresponding accidents are discharge inside the switchgear, leakage of sulfur hexafluoride gas, and joint heating accidents.

The above-mentioned gas concentration measurement device is provided with a gas sampling module, a gas sensor module, a display module and a power supply module; the gas concentration measurement device uses the gas sampling module to extract the gas in the inner space of the switch cabinet and sends it into the gas sensor In the gas sampling part of the sensor module, the unbalanced voltage output signal of the gas sensor module is sent to the display module for real-time display, and the power module provides working power for the gas sampling module, the gas sensor module and the display module.

Further, the through holes of the switch cabinet body include lock holes, operation holes or cooling holes of the switch cabinet.

The gas sensor module includes a semiconductor gas sensor and/or a solid electrolyte electrochemical gas sensor.

Compared with prior art, the advantages of the present invention are:

1. Using the method of extracting the air in the switchgear for analysis, it is possible to sensitively detect the common operating faults of the switchgear in the switchgear, and it is not necessary to stop the running switchgear during work, and it is not necessary to repair the existing switchgear electrical 1. The secondary circuit equipment is modified, the implementation cost is low, and the normal operation of the existing equipment is not affected;

2. When the switchgear is running under live conditions, non-electrical connection is used to detect the operation status of the switchgear, and it can sensitively detect the joint heating, discharge and sulfur hexafluoride gas leakage inside the air-insulated switchgear Such abnormalities are conducive to the early detection and timely processing of faults, which can effectively avoid the expansion of problems and the spread of faults, and create conditions for the safe/stable operation of the entire power transformation and distribution system;

3. The device adopts a portable structure, which is convenient to use in a mobile state, can fully meet the requirements of regular inspections, and is easy to operate and has high detection accuracy.

Description of drawings

Fig. 1 is a schematic block diagram of method steps of the present invention;

Fig. 2 is a schematic diagram of the internal structure of the device of the present invention;

Fig. 3 is a circuit diagram of an embodiment of the present invention.

In the figure, 1 is the device housing, 2 is the air inlet, 3 is the gas sampling module, 4 is the gas sensor module, 5 is the display module, 6 is the power module, 7 is the flexible suction cup,

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

In Fig. 1, detection method of the present invention at least comprises the following steps:

A. For the switchgear with live operation when the cabinet door is closed, use the through hole of the switchgear cabinet outside the cabinet body to extract the gas in the inner space of the cabinet body;

B. For the extracted gas in the cabinet, use a gas concentration measuring device to measure the concentration of a specified characteristic gas;

C, the gas concentration measuring device is provided with multi-channel gas sensor modules, each gas sensor module correspondingly measures the concentration of a certain specified characteristic gas, and each gas sensor module is provided with a balance bridge;

D. The gas sensor module converts the concentration of various specified characteristic gases into electrical signals;

E. Use the method of measuring the unbalanced voltage of each balanced bridge separately or sequentially, and reflect the concentration or concentration change trend of a certain characteristic gas in the cabinet through the value or change of the unbalanced voltage value;

F. Record the unbalanced voltage measurement values corresponding to various specified characteristic gas concentrations in the cabinet by the gas concentration measuring device and the unbalanced voltage measurement values corresponding to the concentration of the same specified characteristic gas in the ambient air during this period;

G. The unbalanced voltage measurement value of various specified characteristic gases measured in the same cabinet for a certain period of time and the unbalanced voltage measurement value corresponding to the same specified characteristic gas in the ambient air and/or other different cabinets at the same time Compare the measured values of the unbalanced voltage corresponding to the same specified characteristic gas in the section;

H. Switch cabinets with abnormal changes in unbalanced voltage measurement values;

I. According to the type of specified characteristic gas corresponding to the abnormal change of the unbalanced voltage measurement value, the corresponding accident type and the corresponding switchgear position are correspondingly obtained;

J. Through the extraction, measurement/analysis and data comparison of the gas in the inner space of the cabinet under the live operation state, compare the unbalanced voltage value of each item representing a certain characteristic gas concentration with the ambient air and/or other switch cabinet positions Comparing the value of the unbalanced voltage representing the characteristic gas concentration item can detect early accidents or early hidden dangers of accidents inside the switchgear, and prevent the expansion or further spread of accidents.

A gas sensor is a sensor that detects a specific gas. It mainly includes semiconductor gas sensors, contact combustion gas sensors and electrochemical gas sensors, among which semiconductor gas sensors are the most used. Its applications mainly include: carbon monoxide gas detection, gas gas detection, gas detection, Freon (R11, R12) detection, ethanol detection in exhaled breath, human oral bad breath detection, etc.

It converts the gas type and its concentration-related information into electrical signals, and according to the strength of these electrical signals, information related to the existence of the gas to be measured in the environment can be obtained, so that detection, monitoring, and alarm can be carried out; It can form an automatic detection, control and alarm system through the interface circuit and computer.

Further, in the technical solution of the present invention, the specified characteristic gases include at least ozone, sulfur hexafluoride and smog, and the corresponding accidents are discharge inside the switchgear, leakage of sulfur hexafluoride gas, and joint heating ACCIDENT.

The gas concentration measurement device is provided with a gas sampling module, at least one gas sensor module, a display module and a power supply module; the gas concentration measurement device uses the gas sampling module to extract the gas in the inner space of the switch cabinet and sends it to The gas sampling part of the gas sensor module, the unbalanced voltage output signal of the gas sensor module is sent to the display module for real-time display, and the power module provides working power for the gas sampling module, the gas sensor module and the display module.

The through holes of the switch cabinet body include lock holes, operation holes or cooling holes of the switch cabinet.

The gas sensor module includes a semiconductor gas sensor and/or a solid electrolyte electrochemical gas sensor.

In this technical solution, the air in the switch cabinet is extracted for qualitative/quantitative analysis, which can sensitively detect three common operating faults of the switchgear in the cabinet: heat generation, discharge, and leakage of sulfur hexafluoride gas, and work It is not necessary to shut down the operating switchgear, nor to modify the electrical primary and secondary circuit equipment of the existing switchgear. The implementation cost is low and does not affect the normal operation of the existing equipment. It is especially suitable for those that have already been built. Power transmission substation/station.

At the same time, when the switchgear is running under the live state, the operation status of the switchgear is detected by means of non-electrical connection, which can sensitively detect abnormal phenomena or early signs of accidents inside the air-insulated switchgear, which is conducive to fault detection. Early detection and timely treatment can effectively avoid the expansion of problems and the spread of faults, and create conditions for the safe/stable operation of the entire power transformation and distribution system.

In Fig. 2, the detection device of the present invention includes a device housing 1 with an air inlet 2 and an air outlet (not shown in the figure); a gas sampling module 3 and a gas sensor module 4 are arranged in the housing , a display module 5 and a power supply module 6.

The air inlet of the device housing is connected to the through hole (not shown in the figure) on the air-insulated switchgear body; the air outlet of the device housing is connected to the atmosphere.

The gas sensor module is connected to the inner space of the air-insulated switch cabinet through the gas sampling module, the air inlet of the device housing and the through hole on the air-insulated switch cabinet.

Further, a flexible suction cup 7 can be set at the end where the air inlet of the device housing is connected to the through-hole air path on the air-insulated switch cabinet body, and the air inlet of the device housing is fixed on the air-insulated switch cabinet body through the flexible suction cup. on the through hole.

Alternatively, a sampling pipe is provided between the air inlet of the device housing and the through hole on the air-insulated switch cabinet, and the air inlet of the device housing is connected to the through hole on the air-insulated switch cabinet through the sampling pipe. One end of the sampling pipe connected to the through hole on the air-insulated switch cabinet body is provided with a flexible suction cup, and the sampling pipe is fixed on the through hole on the air-insulated switch cabinet body through the flexible suction cup.

The detection signal output end of the gas sensor module is electrically connected with the measurement signal input end of the display module.

The power output end of the power module is electrically connected with the power input ends of the gas sampling module, the gas sensor module and the display module.

The gas sampling module in the detection device includes a vacuum pump and a control button switch. The gas suction port of the vacuum pump is connected to the gas path of the sampling tube through the air inlet of the device housing, and the gas outlet of the vacuum pump is connected to the gas of the gas sensor module. The gas circuit of the sampling part is connected; the control button switch is connected in series between the power output end of the power supply module and the winding coil of the vacuum pump.

The gas sensor module in the detection device is a gas sensor.

Specifically, the gas sensor includes an ozone sensor, a sulfur hexafluoride sensor, an air quality sensor, a hydrogen sulfide sensor and/or a smoke sensor.

The display module in the detection device includes a voltmeter and an input selection switch, and the measurement voltage input terminal of the voltmeter is electrically connected to the measurement signal output terminal of the gas sensor module through the input selection switch.

The power module in the detection device includes a storage battery/dry battery pack. Specifically, the power module includes a storage battery/dry battery pack, an anti-reverse connection circuit, a power switch, a voltage stabilizing integrated circuit and a charging socket.

The aforementioned through holes on the air-insulated switchgear body include lock holes, operating holes or cooling holes of the switchgear.

In Fig. 3, the electrical circuit part of the device of the present invention is sequentially composed of a gas sampling module, a gas sensor module, a display module and a power supply module.

In terms of circuit configuration, the gas sampling module 3 includes a vacuum pump motor M and a control button switch SA3; where the control button switch is connected in series with the winding coil of the vacuum pump motor and connected to the positive and negative power output terminals of the power module respectively.

The gas sensitive gas sensor module 4 includes an ozone sensor detection circuit, a sulfur hexafluoride sensor detection circuit, an air quality sensor detection circuit, a hydrogen sulfide sensor detection circuit and a smoke sensor detection circuit; wherein:

The ozone sensor detection circuit includes an ozone sensor CG1, a first resistor R1, a second constant current diode D2 and a seventh adjustable resistor R7. The first pin of the ozone sensor is connected to the positive pole of the output terminal of the power supply module through the first resistor. The ozone sensor The second pin of the ozone sensor is connected to the positive pole of the power output terminal of the power module through the seventh adjustable resistor and the second constant current diode, the third pin of the ozone sensor is connected to the negative pole of the power output terminal of the power module, and the seventh adjustable resistor and the first The connecting end of the two constant current diodes constitutes the detection signal output end of the ozone sensor detection circuit.

The sulfur hexafluoride sensor detection circuit includes the sulfur hexafluoride sensor CG2, the second resistor R2, the third constant current diode D3 and the eighth adjustable resistor R8, the first pin of the sulfur hexafluoride sensor is connected to the power supply through the second resistor The positive pole of the output terminal of the module power supply is connected, the second pin of the sulfur hexafluoride sensor is connected to the positive pole of the power supply output terminal of the power supply module through the eighth adjustable resistor and the third constant current diode, the third pin of the sulfur hexafluoride sensor is connected to the power supply The negative connection of the output terminal of the module power supply, the connection terminal of the eighth adjustable resistor and the third constant current diode constitute the detection signal output terminal of the sulfur hexafluoride sensor detection circuit.

The air quality sensor detection circuit includes the air quality sensor CG3, the fifth resistor R5 and the tenth resistor R10. The pin is connected to the positive pole of the power output terminal of the power module through the fifth resistor, the fourth pin of the air quality sensor is connected to the negative pole of the power output terminal of the power module, and the third pin of the air quality sensor is connected in series with the tenth resistor to form an air quality sensor. The detection signal output terminal of the sensor detection circuit.

The hydrogen sulfide sensor detection circuit includes a hydrogen sulfide sensor CG4, a third resistor R3, an eleventh resistor R11, and a fourth constant current diode D4. The first pin of the hydrogen sulfide sensor is connected to the positive pole of the output terminal of the power supply module through the third resistor. The second pin of the hydrogen sulfide sensor is connected to the positive pole of the power output end of the power module through the fourth constant current diode, the third pin of the hydrogen sulfide sensor is connected to the negative pole of the power output end of the power module, and the third pin of the hydrogen sulfide sensor is connected in series After the eleventh resistor, it constitutes the detection signal output end of the hydrogen sulfide sensor detection circuit.

The smoke sensor detection circuit includes the smoke sensor CG5, the fourth resistor R4, the sixth resistor R6 and the twelfth resistor R12. The first pin of the smoke sensor is connected to the positive pole of the power output terminal of the power module through the fourth resistor, and the second pin of the smoke sensor The pin is connected to the positive pole of the power output end of the power module through the sixth resistor, the third pin of the smoke sensor is connected to the negative pole of the power output end of the power module, and the second pin of the smoke sensor is connected in series with the twelfth resistor to form a smoke sensor The detection signal output terminal of the detection circuit.

The detection signal output end of the ozone sensor detection circuit is connected with the first measurement signal input end of the input selection switch SA2 in the display module.

The detection signal output end of the sulfur hexafluoride sensor detection circuit is connected with the second measurement signal input end of the input selection switch SA2 in the display module.

The detection signal output ends of the air quality sensor detection circuit, the hydrogen sulfide sensor detection circuit and the smoke sensor detection circuit are connected in parallel, and connected with the third measurement signal input end of the input selection switch SA2 in the display module.

The display module 5 includes an input selection switch SA2, a voltmeter V, the thirteenth resistor R13, the fourteenth resistor R14 and the ninth adjustable resistor R9, the first measurement signal input terminal of the input selection switch and the ozone sensor detection circuit The detection signal output terminal is connected, the second measurement signal input terminal of the input selection switch is connected with the detection signal output terminal of the sulfur hexafluoride sensor detection circuit, the third measurement signal input terminal of the input selection switch is connected with the air quality sensor detection circuit, The hydrogen sulfide sensor detection circuit is connected to the detection signal output terminal of the smoke sensor detection circuit, and at the same time connected to the negative pole of the power supply output terminal of the power module through the ninth adjustable resistor. , The negative pole is connected correspondingly, the first input signal terminal of the voltmeter is connected with the detection signal output terminal of the input selection switch, the second input signal terminal of the voltmeter is connected with the positive pole of the power supply output terminal of the power supply module through the thirteenth resistor, and the voltmeter’s The second input signal terminal is also connected to the negative pole of the power supply output terminal of the power supply module through the fourteenth resistor.

The power supply module 6 includes a battery pack B, an isolation diode D1, a charging socket K, a voltage stabilizing integrated circuit IC, a power switch SA1 and a filter capacitor C1. The charging socket is connected in series with the isolation diode and connected between the positive and negative terminals of the battery pack. The positive pole of the battery pack is connected to the power input terminal of the voltage stabilizing integrated circuit through the power switch, the power output terminal of the voltage stabilizing integrated circuit forms the positive pole of the power supply output terminal of the power module, and the ground terminal of the voltage stabilizing integrated circuit is connected to the negative pole of the battery pack to form a power supply. The negative pole of the output terminal of the module power supply, and the filter capacitor are connected between the positive and negative poles of the power supply output terminal of the power supply module.

On the other hand, in terms of circuit function, the gas sampling module 3 includes a vacuum pump motor M and a control button switch SA3. The power input terminal of the vacuum pump motor M and the button switch SA3 are connected in series to the power output terminal of the power module.

The gas sensor module 4 includes an ozone sensor detection circuit, a sulfur hexafluoride sensor detection circuit, an air quality sensor detection circuit, a hydrogen sulfide sensor detection circuit and a smoke sensor detection circuit; wherein:

The output terminal of the ozone sensor CG1 is connected in series with the constant current diode D2 of the output terminal of the ozone sensor and the zero adjustment potentiometer R7, and then connected in parallel to the output terminal of the power supply circuit. Power output.

The output terminal of the sulfur hexafluoride sensor CG2 is connected in series with the constant current diode D3 and the zero adjustment potentiometer R8 and then connected in parallel to the output terminal of the power supply circuit. power output of the circuit.

The output end of the air quality sensor CG3 is connected in parallel with the output end of the power supply circuit after being connected in series with the output end resistance R5, and the auxiliary power end of the air quality sensor CG3 is connected in parallel with the power output end of the power supply circuit.

The output terminals of the hydrogen sulfide sensor CG4 and the smoke sensor CG5 are respectively connected in series with the constant current diode D4 and the output terminal resistor R6 and then connected in parallel with the output terminal of the power supply circuit. The auxiliary power terminals of the hydrogen sulfide sensor CG4 and the smoke sensor CG5 are respectively connected with the resistor R3 and the resistor R4 is connected in series and parallel to the power output end of the power supply circuit; the series connection points of the zero adjustment potentiometers R7 and R8 and the constant current diodes D2 and D3 are respectively connected to the first selection point 1 and the second selection point 2 of the switch SA2; air quality The output ends of the sensor, the hydrogen sulfide sensor and the smoke sensor are respectively connected to the voltage equalizing resistor R10, the voltage equalizing resistor R11 and the voltage equalizing resistor R12, and the other ends of the voltage equalizing resistor R10, the voltage equalizing resistor R11 and the voltage equalizing resistor R12 are all connected to the switching switch SA2 The third selection point 3 is connected, and connected to the negative pole of the power supply through the zero adjustment potentiometer R9.

The hydrogen sulfide sensor, sulfur hexafluoride sensor and ozone sensor in this circuit are recommended to use solid electrolyte electrochemical gas sensor.

In the display module 5, the voltage dividing resistor R13 and the voltage dividing resistor R14 are connected in parallel to the output terminal of the power supply circuit after being connected in series, and the series connection point of the voltage dividing resistor R13 and the voltage dividing resistor R14 is connected to the signal input terminal of the voltmeter V, and the voltmeter V The other signal input end of the switch is connected to the common point of switch SA2, the working power input end of the voltmeter V is connected in parallel with the power output end of the power supply circuit, and the voltmeter V is a digital display voltmeter.

In the power supply module 6, the positive pole of the charging socket K is connected to the battery B through the isolation diode D1, the positive pole of the battery B is connected to the input terminal of the voltage stabilizing integrated circuit IC through the power switch SA1, and the output terminal of the voltage stabilizing integrated circuit IC and the adjustment terminal A filter capacitor C1 is connected in parallel between them, and the adjustment terminal of the voltage stabilizing integrated circuit IC is connected to the negative pole of the battery B and the charging socket K. Among the above components, the diode D1 is used to charge the internal battery through the charging socket, and the polarity of the charger is reversed; the voltage stabilizing integrated circuit IC adopts the 7805 type, which is used to stabilize the battery voltage at 5V and supply power to the sensors at all levels; C1 is Filter capacitor for stabilizing the DC power supply voltage.

In addition, it is obvious that the gas sensor module in this circuit is used to convert various gas concentration signals into electrical signals. In this module circuit, resistors R1, R2, R3, and R4 are the auxiliary power supply resistors of the sensor, used for Provide stable DC current for the electrolyte or auxiliary power supply inside the sensor; diodes D2, D3, and D4 are constant current diodes at the output of the sensor. Since the ozone, sulfur hexafluoride and hydrogen sulfide sensors in this circuit are constant current outputs, their The current at the output terminal needs to be fixed by a constant current diode, and at the same time provide convenience for taking out the signal voltage; resistors R5 and R6 are the output load resistors of the odor sensor and smoke sensor respectively, which provide convenience for taking out the signal voltage; resistors R10, R11 and R12 are used for To simplify the circuit, connect the output terminals of the sensors that detect the smell of heat, hydrogen sulfide, and smoke. This is because the output resistance of various gas sensors is inversely proportional to the characteristic gas concentration, and the resistance values of resistors R10, R11, and R12 are the same. The resistance value is much greater than the maximum output resistance of the three sensors, so the potentials of points a, b, and c in the figure can be displayed through one point (the third selection point 3 of the selection switch SA2 in the figure), and the potentials of the three points in the figure The potential is approximately equal to the average value of the voltages at points a, b, and c. As long as one sensor feels abnormal and the resistance value becomes smaller, the potential at point 3 will drop; resistors R13, R14 and diodes D2, D3, D4 and resistors R5 and R6 form a balanced electric bridge, so that the change of the output resistance of each sensor can be detected with high sensitivity; V is a digital voltmeter, which is used to visually display the unbalanced voltage of the balanced electric bridge; resistors R7, R8, and R9 are used for Zero adjustment to obtain reference gas concentration for easy detection.

Since there are some characteristic gases such as particulate matter, hydrogen sulfide, and ozone in the air, and they vary from place to place, before testing the switchgear equipment, the outside air can be obtained through the gas sampling module, and the ambient air can be set as the reference value and adjusted separately. Adjustable resistors (potentiometers) R7, R8, R9 are balanced to the bridge, the voltmeter V has no reading, and then detect the switchgear equipment, and then the concentration or content of the characteristic gases in the air inside the equipment and the characteristic gases in the outside air can be compared. difference, making it easier to detect devices.

The detection item switch SA2 is used to switch the three detection items of "heat generation", "SF6 leakage" and "discharge". The first selection point 1 of the switch is to detect "discharge" fault, and the second selection point 2 is to detect " SF6 (sulfur hexafluoride) leakage" fault, the third option point 3 is to detect "joint heating" fault.

The exhaust end of the gas sampling device 2 in this device is connected with the gas sampling part of the gas sensor module 3 . Among them, SA3 is the air intake button switch. Press the SA3 vacuum pump to run, inhale gas from the outside, and blow into the gas sensor module from the exhaust end for the sensor to judge.

In actual use, turn on the power switch SA1, and the device starts to work. At this time, you need to wait for about 1 minute. After all the sensors are warmed up and enter a steady state, you can start measuring. The output resistance of each sensor changes through the balance bridge. It is reflected on the voltmeter. In order to make the measured data intuitive, you can first switch the selector switch to each position for zero adjustment, and then align the air intake port of the detection device with the lock hole, operation hole or heat dissipation hole of the switch cabinet door. hole, press SA3 to turn on the vacuum pump to inhale, and the device can display the unbalanced voltage of the balanced bridge corresponding to various characteristic gas concentrations, and compare the unbalanced voltage of each item with the ambient air and the values of other switch cabinet positions. By comparison, it can clearly show that there are abnormal switchgear equipment positions inside.

Since the present invention adopts the non-electrically connected gas analysis method to collect the operating state parameters of the measured object, it can sensitively detect the three most common operating faults of the switchgear in the cabinet, and there is no need to check the operating switch cabinet during the detection work. Shutdown does not affect the normal operation of existing equipment, is conducive to the early detection and timely treatment of faults, can effectively avoid the expansion of problems and the spread of faults, and creates conditions for the safe/stable operation of the entire power transformation and distribution system.

At the same time, the device adopts a portable structure design, which is convenient to use in a mobile state. When the closed combination switchgear is running with electricity, it can obtain multiple air-insulated switchgear positions in a "one-to-many" manner in a timely and low-cost manner. The operation status of the internal switchgear or its abnormal operation information is found, the detection implementation cost is low, and the detection accuracy is high, which solves many problems such as the technical transformation of the existing equipment without power failure and the improvement of device monitoring methods.

The invention can be widely used in the field of operation monitoring of various closed combined electric appliances/air insulation switch cabinets.

Claims (4)

1. the detection method of an internal faults of switch cabinet comprises it is characterized in that the cabinet of switch cubicle:

Be in the switch cubicle of the charging operation under closed condition for the cabinet door, in the cabinet outside, utilize the through hole of switch cabinet body, extract the gas of cabinet inner space;

For gas in the cabinet that is drawn out of, adopt gas concentration measuring apparatus to carry out the measurement of concetration of certain specific characteristic gas;

Multichannel gas sensor module is set in described gas concentration measuring apparatus, the corresponding concentration of measuring a certain specific characteristic gas of each road gas sensor module, each road gas sensor module arranges a balanced bridge;

Described gas sensor module is transformed into electric signal with the concentration of various specific characteristic gases;

Adopt and to measure respectively or successively the method for the unbalance voltage of each balanced bridge, the variation of numerical value or numerical value by the unbalance voltage value comes the concentration of certain characteristic gas in corresponding reflection cabinet or the variation tendency of concentration;

Record respectively gas concentration measuring apparatus to the corresponding unbalance voltage value of various specific characteristic gas concentrations in cabinet and should be in the period the corresponding unbalance voltage value of the concentration of specific characteristic gas of the same race in surrounding air;

With same cabinet sometime in unbalance voltage value and the surrounding air of the section various specific characteristic gases of surveying the corresponding unbalance voltage value of specific characteristic gas of the same race and/or other different cabinets at one time section interior specific characteristic gas of the same race the measured value of corresponding unbalance voltage compare;

Find the switch cubicle of unbalance voltage value ANOMALOUS VARIATIONS;

According to unbalance voltage value abnormal change the kind of corresponding specific characteristic gas, correspondence draws corresponding accident kind and corresponding switch cubicle position in storehouse;

By extraction, measurement/analysis and the Data Comparison to charging operation state lower cabinet body inner space gas, each is represented that the unbalance voltage numerical value of certain characteristic gas concentration project compares with the numerical value of the unbalance voltage that represents this kind characteristic gas concentration project of ambient air and/or other switch cubicle positions in storehouse, and demonstrating inside has abnormal switch cubicle equipment position in storehouse.

2. according to the detection method of internal faults of switch cabinet claimed in claim 1, it is characterized in that described specific characteristic gas comprises ozone, sulfur hexafluoride and smog at least, discharge, sulfur hexafluoride gas that its corresponding accident is respectively inside switch cabinet leak and the conductor joint heating accident.

3. according to the detection method of internal faults of switch cabinet claimed in claim 1, it is characterized in that being provided with in described gas concentration measuring apparatus gas sampling module, gas sensor module, display module and power module; Described gas concentration measuring apparatus utilizes the gas sampling module to extract the gas of switch cabinet inner space, it is sent into the gas sampling part of gas sensor module, described gas sensor module is used for various gas concentration signals are transformed into electric signal, the unbalance voltage output signal of gas sensor module is sent into display module and is shown in real time, and described power module provides working power for gas sampling module, gas sensor module and display module.

4. according to the detection method of claim 1 or 3 described internal faults of switch cabinet, it is characterized in that the through hole of described switch cabinet body, comprise lockhole, handle hole or the louvre of switch cubicle; Described gas sensor module comprises semiconductor gas sensor and/or solid electrolyte Electro-chemical Gas Sensor.

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