CN104374421A - Transducer for measuring tiny water in oil and method for on-line real-time monitoring of temperature and humidity in oil - Google Patents
Transducer for measuring tiny water in oil and method for on-line real-time monitoring of temperature and humidity in oil Download PDFInfo
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- CN104374421A CN104374421A CN201310360278.5A CN201310360278A CN104374421A CN 104374421 A CN104374421 A CN 104374421A CN 201310360278 A CN201310360278 A CN 201310360278A CN 104374421 A CN104374421 A CN 104374421A
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Abstract
The invention relates to a transducer for measuring tiny water in oil and a method for on-line real-time monitoring of temperature and humidity in oil. The transducer for measuring the tiny water in the oil comprises a capacitive humidity sensitive element, a capacitance measuring circuit, a resistive temperature sensitive element, a resistance measuring circuit, an MCU control unit and a power supply module. The capacitance measuring circuit is used for generating capacitance measuring signals according to the capacitance values of the capacitive humidity sensitive element. The resistance measuring circuit is used for generating resistance measuring signals according to the resistance values of the resistive temperature sensitive element. The MCU control unit calculates humidity values according to the capacitance measuring signals output by the capacitance measuring circuit, calculates temperature values according to the resistance measuring signals output by the resistance measuring circuit and generates humidity information output signals and temperature information output signals so that the humidity information output signals and the temperature information output signals can be output through an output circuit. The power supply module is used for providing a power supply for the transducer for measuring the tiny water in the oil. The transducer for measuring the tiny water in the oil has the advantages that hardware cost is low, the measuring accuracy is high, and the stability is high.
Description
Technical field
The present invention relates to power equipment, more particularly, relate to a kind of method for humiture real time on-line monitoring in water gaging transmitter micro-in the oil of Monitoring Power Transformer and oil.
Background technology
Transformer oil is the inner important insulating medium of power transformer, and it mainly plays insulation, cooling and extinguishing arc in power transformer, and oily quality directly has influence on the electric property of transformer.So certain electrical insulation strength must be had in transformer oil in operational process.Although the micro-water content in transformer oil is very little, the insulating property of oil are but had a significant impact.Moisture can not only reduce the voltage breakdown of insulation system and increase dielectric loss, and it will participate in the chemical degradation reaction of the macromolecular materials such as oilpaper fiber directly, impel these material degradations aging, thus accelerate the deterioration of insulation system properties.This is one and develops irreversible historical process gradually with transformer working time.Therefore, the inspection of content of micro water in transformer oil has the very important meaning to device security, stable operation.So carrying out real time on-line monitoring to the content of micro-water in transformer oil is the important evidence of safeguarding transformer and overhauling.
In existing detection oil humiture technical scheme in, as shown in Figure 1, Humidity Detection generally adopts the special integration module that can detect humidity above market to detect, and sense data processes in humidity measurement module, and MCU directly reads humidity value by iic bus; Chip for detected temperatures is very many, and as DS18B20 or substitute products of the same type, same sense data processes in temperature test module, and MCU just directly can read current temperature value by unibus.Owing to adopting special integration module to detect humidity and temperature, there is the high defect of hardware cost in prior art.
In addition, existing humidity measurement module is in the context of detection to trace moisture content, and precision does not reach requirement, therefore cannot accurately detect micro-moisture in oil.Go back the problem of existence and stability difference simultaneously.
Summary of the invention
The technical problem to be solved in the present invention is, for the defect that water gaging transmitter hardware cost micro-in existing oil is high, there is provided a kind of and use micro-water gaging transmitter in the oil of discrete sensing element measuring tempeature and humidity, and use micro-water gaging transmitter in this oil to carry out the method for humiture real time on-line monitoring in oil.
The technical solution adopted for the present invention to solve the technical problems is: construct micro-water gaging transmitter in a kind of oil, comprising:
Condenser type humidity sensing element;
Capacitance measurement circuit, for measuring the capacitance of described condenser type humidity sensing element and producing capacitance measurement signal;
Resistance temperature sensor;
Resistance measuring circuit, for measuring the resistance value of described resistance temperature sensor and producing resistance measuring signals;
MCU control unit, its capacitance measurement signal exported according to described capacitance measurement circuit calculates humidity value, the resistance measuring signals accounting temperature value that exports according to resistance measuring circuit produce humidity information output signal and temperature information output signal;
Output circuit, for exporting described humidity information output signal and temperature information output signal; And
Supply module, for being converted to by DC/DC the power supply that in described oil, in micro-water gaging transmitter, each circuit block needs by the power supply of outside.
In oil of the present invention in micro-water gaging transmitter, described capacitance measurement signal and described resistance measuring signals are simulating signal, and in described oil, micro-water gaging transmitter also comprises:
Analog to digital conversion circuit, is sent to described MCU control unit after the simulating signal for described capacitance measurement circuit and resistance measuring circuit being exported converts digital signal to.
In oil of the present invention in micro-water gaging transmitter, described condenser type humidity sensing element is macromolecule membrane condenser type humidity sensing element, and described capacitance measurement circuit comprises:
Reference capacitance and the first constant current source for charging for described reference capacitance;
Be parallel to the first analog switch of described reference capacitance, described first analog switch according to the discharge control signal of described MCU control unit for described reference capacitance provides discharge channel;
For the second constant current source for described condenser type humidity sensing element charging, wherein the second constant current source is identical with the first constant current source performance parameter;
Be parallel to the second analog switch of described condenser type humidity sensing element, described second analog switch according to the discharge control signal of described MCU control unit for described condenser type humidity sensing element provides discharge channel;
First instrumentation amplifier, for amplifying the voltage difference of reference capacitance and condenser type humidity sensing element; The voltage of wherein said reference capacitance is sent to the first input end of the first instrumentation amplifier; The voltage of described condenser type humidity sensing element is sent to the second input end of the first instrumentation amplifier; The output terminal of described first instrumentation amplifier is connected to the input end of analog-digital conversion circuit as described.
In oil of the present invention in micro-water gaging transmitter, described MCU control unit sends discharge control signal to described first analog switch and the second analog switch simultaneously, and is more than or equal to two times of the duration of charging discharge time.
In oil of the present invention in micro-water gaging transmitter,
Described resistance measuring circuit comprises:
The second voltage amplifier and the second instrumentation amplifier that the first voltage amplifier that reference resistance, the 3rd constant current source, enlargement factor are one times, enlargement factor are two times; Wherein
Reference resistance and described resistance temperature sensor are contacted, and described 3rd constant current source provides electric current to the series circuit of reference resistance and resistance temperature sensor;
Voltage on the series circuit of described reference resistance and resistance temperature sensor outputs to the first input end of described second instrumentation amplifier after being amplified by described first voltage amplifier, voltage on described resistance temperature sensor outputs to the second input end of described second instrumentation amplifier after being amplified by described second voltage amplifier, the output terminal of described second instrumentation amplifier is connected to the input end of analog-digital conversion circuit as described.
In oil of the present invention in micro-water gaging transmitter, described output circuit comprises RS485 communication interface circuit and/or 4 ~ 20mA analog interface circuit; Wherein, described MCU control unit adopts ModBUS communication protocol by described RS485 communication interface circuit communication.
In oil of the present invention in micro-water gaging transmitter, described MCU control unit comprises:
Filtering processing module, for carrying out moving average filter process to the capacitance measurement signal collected and resistance measuring signals;
Humidity computing module, for calculating humidity value according to the capacitance measurement signal after filtering process;
Temperature computation module, for according to the resistance measuring signals accounting temperature value after filtering process; And
Quality concentration calculation module, for calculating quality concentration according to described humidity value and described temperature value.
In oil of the present invention in micro-water gaging transmitter, described moving average filter process comprises:
Often obtain a sampled value, according to first in first out, N number of sampled value continuous sampling obtained to be placed in a queue and to sort;
Remove maximum sampled value and minimum sampled value;
Arithmetic mean is carried out to a remaining N-2 sampled value, to obtain the data after filtering process;
Wherein, N is fixed number, gets the integer between 50 ~ 100, and described sampled value comprises described capacitance measurement signal and resistance measuring signals.
The technical solution adopted for the present invention to solve the technical problems is: provide a kind of and use micro-water gaging transmitter in above-mentioned oil to carry out the method for humiture real time on-line monitoring in oil, comprising:
Send a control signal to capacitance measurement circuit;
Gather and represent the capacitance measurement signal of humidity in oil and represent the resistance measuring signals of temperature in oil;
Respectively moving average filter process is carried out to described capacitance measurement signal and resistance measuring signals;
Humidity value is calculated according to the capacitance measurement signal after filtering process;
According to the resistance measuring signals accounting temperature value after filtering process;
Quality concentration is calculated according to described humidity value and described temperature value; And
According to described humidity value and described temperature value produce respectively humidity information output signal and temperature information output signal and exported by output circuit.
In oil of the present invention humiture real time on-line monitoring method in, described moving average filter process comprises:
Often obtain a sampled value, according to first in first out, N number of sampled value continuous sampling obtained to be placed in a queue and to sort;
Remove maximum sampled value and minimum sampled value;
Arithmetic mean is carried out to a remaining N-2 sampled value, to obtain the data after filtering process;
Wherein, N is fixed number, gets the integer between 50 ~ 100, and described sampled value comprises described capacitance measurement signal and resistance measuring signals.
Implement the present invention, there is following beneficial effect: owing to have employed discrete condenser type humidity sensing element and resistance temperature sensor, the simple capacitance measurement circuit of integrated structure and resistance measuring circuit, by MCU control unit, measurement data is focused on, make micro-water gaging transmitter in oil of the present invention have the low advantage of hardware cost.
In addition, owing to adopting trace moisture content in macromolecule membrane condenser type humidity sensing element test oil, and adopt differential measurement method, can effectively nonlinear error reduction, improve transducer sensitivity, reduce interference, reduce the impact of stray capacitance, therefore high, the good stability of measuring accuracy.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:
Fig. 1 is the system chart of micro-water gaging transmitter in the oil of prior art;
Fig. 2 is the system chart of micro-water gaging transmitter in oil of the present invention;
Fig. 3 is the schematic diagram of capacitance measurement circuit one embodiment in oil of the present invention in micro-water gaging transmitter;
Fig. 4 is the capacitor charge and discharge sequential chart in measuring process of capacitance measurement circuit shown in Fig. 3;
Fig. 5 is the schematic diagram of resistance measuring circuit one embodiment in oil of the present invention in micro-water gaging transmitter;
Fig. 6 uses micro-water gaging transmitter in oil of the present invention to carry out the process flow diagram of the method for humiture real time on-line monitoring in oil.
Embodiment
The present invention conceives micro-water gaging transmitter in a kind of oil, and utilizes this transmitter to carry out the method for temperature and humidity real time on-line monitoring.The electric signal that the present invention adopts electric capacity, resistance measuring circuit temperature and humidity in current oil to be transformed into MCU can to identify, measuring accuracy is high, good stability, with low cost.
As shown in Figure 2, in oil of the present invention, micro-water gaging transmitter comprises condenser type humidity sensing element, resistance temperature sensor, humidity measuring circuit, temperature measuring circuit, analog to digital conversion circuit (ADC), MCU control unit, output circuit (comprising analogue quantity output circuit and/or communication digital output circuit) and supply module.
Wherein, capacitance measurement circuit is for measuring the capacitance of condenser type humidity sensing element and producing capacitance measurement signal.Resistance measuring circuit is used for the resistance value of measuring resistance formula temperature-sensing element (device) and produces resistance measuring signals.The resistance measuring signals accounting temperature value that the capacitance measurement signal that MCU control unit exports according to capacitance measurement circuit calculates humidity value, export according to resistance measuring circuit also produces humidity information output signal and temperature information output signal to be exported by output circuit.Supply module is used for the power supply power supply of outside being converted to each circuit block needs by DC/DC.
It should be noted that, in various embodiments of the present invention, analog to digital conversion circuit can be independently circuit, also can be integrated in capacitance measurement circuit and resistance measuring circuit.In the previous case, capacitance measurement circuit and resistance measuring circuit outputting analog signal, after converting digital signal to, be resent to MCU control unit by analog to digital conversion circuit.Capacitance measurement circuit and the direct output digit signals of resistance measuring circuit outputting analog signal in the case of the latter.
As preferably, in oil of the present invention, externally export can by RS485 communication interface circuit (such as adopt MODBUS agreement carry out digital communication) for micro-water gaging transmitter, export 4 ~ 20MA electric current by 4 ~ 20MA analog interface circuit, can be selected wherein one or both.
In a preferred embodiment of the invention, the resistance temperature sensor made of the humidity and temperature sensitive element humidity sensing element (the condenser type humidity sensing element of such as Kapton or the condenser type humidity sensing element of other types) that adopts macromolecule membrane to make respectively and platinum resistance thermometer sensor.But the present invention is not limited thereto, also can adopt condenser type humidity sensing element and the resistance temperature sensor of other types.
As shown in Figure 3, capacitance measurement circuit comprises: the first constant current source Is1, the second constant current source Is2, reference capacitance C
ref, the first analog switch SW1, the second analog switch SW2 and the first instrumentation amplifier P1.Wherein
First constant current source Is1 is used for for reference capacitance C
refcharging; First analog switch SW1 is parallel to reference capacitance C
ref, it is reference capacitance C according to the discharge control signal of MCU control unit
refdischarge channel is provided.
Second constant current source Is2 is used for charging for condenser type humidity sensing element Cx, and it should be noted that, the second constant current source Is2 is identical with the first constant current source Is1 performance parameter.Second analog switch SW2 is parallel to condenser type humidity sensing element Cx, and according to the discharge control signal of MCU control unit for condenser type humidity sensing element Cx provides discharge channel.
First instrumentation amplifier P1 is used for reference capacitance C
refamplify with the voltage difference of condenser type humidity sensing element Cx.Wherein reference capacitance C
refvoltage be sent to the first input end of the first instrumentation amplifier; The voltage of condenser type humidity sensing element Cx is sent to the second input end of the first instrumentation amplifier; The output terminal of the first instrumentation amplifier is connected to the input end of analog to digital conversion circuit.
MCU control unit sends discharge control signal Ctl to described first analog switch SW1 and the second analog switch SW2 simultaneously, and is more than or equal to two times of the duration of charging discharge time.
In embodiments of the invention, capacitance measurement circuit adopts constant current source charging method to carry out charging to two small capacitances and detects, and adopts this scheme only namely can be realized high precision, the high-frequency measurement of electric capacity by MCU and minority chip.Owing to have employed differential measurement, the present invention can effectively nonlinear error reduction, improve transducer sensitivity, reduce interference, reduce the impact of stray capacitance.Select high performance analog switch (such as field effect transistor or other switching devices) greatly can reduce the impact of Charge injection effect simultaneously.
The once complete measuring process of capacitance measurement circuit is as follows:
First, it is closed that MCU control circuit controls the first analog switch SW1, the second analog switch SW2 simultaneously, allows electric capacity two terminal shortcircuit, with to reference capacitance C
refdischarge with condenser type humidity sensing element Cx, discharge time is T1.
Then, MCU control circuit controls the first analog switch SW1 simultaneously, the second analog switch SW2 turns off, and two identical constant current sources (i.e. the first constant current source Is1, the second constant current source Is2) are respectively to reference capacitance C
refcharge with condenser type humidity sensing element Cx, the duration of charging is T2.As preferably, in order to ensure the precision calculated, discharge time, T1 was greater than 2 times that equal duration of charging T2.
In identical duration of charging T2, to reference capacitance C
refwith the charging of condenser type humidity sensing element Cx.Capacitance calculation formula is as follows:
U1＝C
ref*I*T2
U2＝Cx*I*T2
Uc=K
1*ΔU＝K
1*（U2-U1）=(Cx-C
ref）*K
1*I*T2
Cx=C
ref+Uc/(I*T2*K
1)
Wherein, the charging voltage that the charging voltage that U1 is reference capacitance, U2 are condenser type humidity sensing element Cx, I represents the current value of constant current source, K
1represent the enlargement factor of the first instrumentation amplifier P1, Uc is the voltage sampling signal (i.e. capacitance measurement signal) that the first instrumentation amplifier P1 exports.Reference capacitance C
refselect high-precision electric capacity.
Because Δ U is too little, be easy to be subject to common mode interference, in order to improve antijamming capability, need to amplify Δ U with instrumentation amplifier, being amplified K
1output signal U c doubly.Transformed by ADC conversion circuit again, sampled data is stored.So far, once complete sampling process terminates, and as shown in Figure 4, wherein T1 is discharge time to discharge and recharge sequential, and T2 is the duration of charging.
As shown in Figure 5, resistance measuring circuit comprises: reference resistance R
ref, the 3rd constant current source Is3, the enlargement factor first voltage amplifier A1 that is a times, enlargement factor be two times the second voltage amplifier A2 and the second instrumentation amplifier P2.Wherein the second voltage amplifier A2 the second resistance R2 of comprising amplifier a2, being connected to the first resistance R1 between amplifier a2 negative input end and ground and being connected between amplifier a2 negative input end and output terminal.Wherein
3rd constant current source Is3 is to reference resistance R
refelectric current is provided with the series circuit of resistance temperature sensor Rx;
Reference resistance R
refthe first input end of the second instrumentation amplifier P2 is outputted to after being amplified by the first voltage amplifier with the voltage on the series circuit of resistance temperature sensor Rx, voltage on resistance temperature sensor Rx outputs to second input end of described second instrumentation amplifier P2 after being amplified by the second voltage amplifier A2, the output terminal of the second instrumentation amplifier P2 is connected to the input end of analog to digital conversion circuit.
In one embodiment of the invention, resistance measuring circuit adopts three-wire system constant current source to drive method to drive platinum resistance temperature sensing element.Three-wire system constant current source drives method to refer to the fixed resistance (zero degree resistance) eliminating platinum resistance temperature sensing element with hardware circuit, directly measures the resistance change of platinum resistance temperature sensing element.
Three-wire system constant current source drives method high-acruracy survey scheme, reference resistance and platinum resistance temperature sensing element are connected in series, drive with constant current source, the each element of circuit will produce corresponding voltage, and platinum resistance temperature sensing element directly can be measured by amplifying circuit below and A/D converter because of the voltage of the resistance of temperature variation part.Be characterized in the resistance change directly measuring platinum resistance temperature sensing element, A/D converter utilization ratio be high, circuit output voltage and resistance change linear.Platinum resistance temperature sensing element adopts three-wire system connection effectively can eliminate the impact of conductor resistance and self-heating effect.Utilize MCU control unit to control imbalance and the systematic error produced of drifting about that twice measuring voltage can avoid wiring barrier voltage and amplifier, A/D converter, can also calibrate platinum resistance temperature sensing element precision.Constant current source and A/D converter share reference data, like this according to the stoichiometric ratio shift theory of A/D converter, can eliminate the error that reference data instability produces, are easy to obtain exporting to two sections of voltages of instrumentation amplifier and the relation of resistance by Fig. 5:
U1=I*(R
ref+ Rx), U2=2*I*Rx; Wherein I is the drive current of constant current source;
Ur=K
2*ΔU=K
2*（U2-U1）=K
2*（Rx-R
ref）*I；
Rx=R
ref+Ur/(K
2*I)
Wherein K
2represent the enlargement factor of the second instrumentation amplifier.
MCU control unit comprises filtering processing module, for carrying out moving average filter process to the capacitance measurement signal collected and resistance measuring signals; Humidity computing module, for calculating humidity value according to the capacitance measurement signal after filtering process; Temperature computation module, for according to the resistance measuring signals accounting temperature value after filtering process; And quality concentration calculation module, for calculating quality concentration according to described humidity value and described temperature value.
Filtering processing module in MCU control unit is to gathering the electric capacity and the process of resistance data employing moving average filter that store, and concrete disposal route is as follows:
Often obtain a sampled value, according to first in first out, N number of sampled value continuous sampling obtained to be placed in a queue and to sort;
Remove maximum sampled value and minimum sampled value;
Arithmetic mean is carried out to a remaining N-2 sampled value, to obtain the data after filtering process;
Wherein, N is fixed number, gets the integer between 50 ~ 100, and described sampled value comprises described capacitance measurement signal and resistance measuring signals.
In other words, sampled value continuous sampling obtained is placed in a queue, and the length of queue is fixed as N.According to the rule of queue first in first out, sample new data at every turn and be placed on tail of the queue, and throw away a secondary data of original head of the queue, N number of data in queue are sorted, remove maximal value and minimum value, then arithmetic mean is carried out to the data in queue, just can obtain more accurate result.
Through on-the-spot test, this filtering algorithm can effectively overcome because the fluctuation that accidentalia causes is disturbed, also filtering process can be carried out to the signal of general random interference, measured parameter is slowly changed to humidity, temperature etc. and has good filter effect, and the execution time of whole algorithm can complete in Millisecond, there is good real-time, the requirement that precision is high, real-time is good can be met.
The following Formulae For Atmospheric Humidity of humidity computing module in MCU control unit calculates humidity value: humidity and capacitance linear, Humi=K*cap+B, wherein Humi represents current humidity value, Cap represents by the capacitance parameter measured by sensor, K and B represents two coefficients of sensor, and the performance parameter by sensor is determined.
The following temperature computation formulae discovery temperature value of temperature computation module in MCU control unit: the linear relationship of temperature and resistance value is not very strict, in order to obtain more accurate result, temperature can carry out looking into temperature according to resistance value and resistance correspondence table obtains, and the correspondence table of temperature and resistance is determined to provide by the performance parameter of concrete sensor.
The following PPM computing formula of quality concentration calculation module in MCU control unit calculates quality concentration: PPM=Hum*10
(A/T+273.16)+B), wherein, PPM represents quality concentration, T representation temperature, and Humi represents current humidity value, and A, B parameter all needs to carry out measurement to oil and obtains.
Digital simulation output circuit module: numerical portion adopts isolation RS 485, in order to adapt to the situation of the many equipment of many main frames, adopts MODBUS communication protocol.The electric current that mimic channel exports 4-20MA exports, and can meet the diversified demand of Different field.
Fig. 6 uses micro-water gaging transmitter in oil of the present invention to carry out the process flow diagram of the method for humiture real time on-line monitoring in oil.As shown in Figure 6, when micro-water gaging transmitter works on power in oil of the present invention at every turn, first carry out system initialization, calibrate, keep stored parameter and CRC check in mind.After completing these steps, can start to measure, real-time outputting analog signal (4 ~ 20mA electric current) in measuring process, and respond MODBUS instruction executing instruction operations.
The method that in oil of the present invention, micro-water gaging transmitter carries out humiture real time on-line monitoring in oil is utilized to comprise the steps:
Send a control signal to capacitance measurement circuit and resistance measuring circuit, such as, transmit control signal to the first analog switch in capacitance measurement circuit and the second analog switch, the duration of charging of control capacitance and discharge time.
Gather and represent the capacitance measurement signal of humidity in oil and represent the resistance measuring signals of temperature in oil;
Respectively moving average filter process is carried out to described capacitance measurement signal and resistance measuring signals;
Humidity value is calculated according to the capacitance measurement signal after filtering process;
According to the resistance measuring signals accounting temperature value after filtering process;
Quality concentration is calculated according to described humidity value and described temperature value; And
According to described humidity value and described temperature value produce respectively humidity information output signal and temperature information output signal and exported by output circuit.
The content of micro-water in the thin film capacitor type humidity sensing element monitoring insulation that this product adopts macromolecular material (such as polyimide or other macromolecular materials) to make, the mobile equilibrium of a moisture is there is between this macromolecule membrane and insulating oil, when Water in oil amount changes, the hydrone quantity of thin film adsorbs also changes accordingly, thus cause the relative dielectric constant of film to change, due to electric capacity and specific inductive capacity linear, the variable quantity of electric capacity to be converted into by double measurement circuit the electric signal that MCU can identify by us, just can realize the on-line monitoring to micro-water content in oil.
Consider the variation of onsite application situation and the request for utilization of the many equipment of many main frames, this product externally exports and adopts MODBUS agreement and 4-20MA electric current to export.
Technical matters to be solved by this invention is, can accurately reliable monitoring micro-moisture in oil being carried out to real-time online.
The metering circuit of resistance, electric capacity is key point of the present invention, and the precision of resistance capacitance test determines the precision of product.The output stability of constant-current source circuit is also this key point of the present invention, and in capacitance measurement circuit, the error of the current characteristic curve of two constant current source outputs will control in very little scope, requires substantially identical in theory.In the present invention, MCU control unit carries out filtering process and abnormal judgement to the resistance value collected, capacitance, ensure that the precision degree of result is high, good reliability.
Claims (10)
1. a micro-water gaging transmitter in oil, is characterized in that, comprising:
Condenser type humidity sensing element;
Capacitance measurement circuit, for measuring the capacitance of described condenser type humidity sensing element and producing capacitance measurement signal;
Resistance temperature sensor;
Resistance measuring circuit, for measuring the resistance value of described resistance temperature sensor and producing resistance measuring signals;
MCU control unit, its capacitance measurement signal exported according to described capacitance measurement circuit calculates humidity value, the resistance measuring signals accounting temperature value that exports according to resistance measuring circuit produce humidity information output signal and temperature information output signal;
Output circuit, for exporting described humidity information output signal and temperature information output signal; And
Supply module, for being converted to by DC/DC the power supply that in described oil, in micro-water gaging transmitter, each circuit block needs by the power supply of outside.
2. micro-water gaging transmitter in oil according to claim 1, is characterized in that, described capacitance measurement signal and described resistance measuring signals are simulating signal, and in described oil, micro-water gaging transmitter also comprises:
Analog to digital conversion circuit, is sent to described MCU control unit after the simulating signal for described capacitance measurement circuit and resistance measuring circuit being exported converts digital signal to.
3. micro-water gaging transmitter in oil according to claim 2, is characterized in that, described condenser type humidity sensing element is macromolecule membrane condenser type humidity sensing element, and described capacitance measurement circuit comprises:
Reference capacitance and the first constant current source for charging for described reference capacitance;
Be parallel to the first analog switch of described reference capacitance, described first analog switch according to the discharge control signal of described MCU control unit for described reference capacitance provides discharge channel;
For the second constant current source for described condenser type humidity sensing element charging, wherein the second constant current source is identical with the first constant current source performance parameter;
Be parallel to the second analog switch of described condenser type humidity sensing element, described second analog switch according to the discharge control signal of described MCU control unit for described condenser type humidity sensing element provides discharge channel;
First instrumentation amplifier, for amplifying the voltage difference of reference capacitance and condenser type humidity sensing element; The voltage of wherein said reference capacitance is sent to the first input end of the first instrumentation amplifier; The voltage of described condenser type humidity sensing element is sent to the second input end of the first instrumentation amplifier; The output terminal of described first instrumentation amplifier is connected to the input end of analog-digital conversion circuit as described.
4. micro-water gaging transmitter in oil according to claim 3, is characterized in that, described MCU control unit sends discharge control signal to described first analog switch and the second analog switch simultaneously, and is more than or equal to two times of the duration of charging discharge time.
5. micro-water gaging transmitter in oil according to claim 2, is characterized in that,
Described resistance measuring circuit comprises:
The second voltage amplifier and the second instrumentation amplifier that the first voltage amplifier that reference resistance, the 3rd constant current source, enlargement factor are one times, enlargement factor are two times; Wherein
Reference resistance and described resistance temperature sensor are contacted, and described 3rd constant current source provides electric current to the series circuit of reference resistance and resistance temperature sensor;
Voltage on the series circuit of described reference resistance and resistance temperature sensor outputs to the first input end of described second instrumentation amplifier after being amplified by described first voltage amplifier, voltage on described resistance temperature sensor outputs to the second input end of described second instrumentation amplifier after being amplified by described second voltage amplifier, the output terminal of described second instrumentation amplifier is connected to the input end of analog-digital conversion circuit as described.
6. micro-water gaging transmitter in oil according to claim 1, is characterized in that, described output circuit comprises RS485 communication interface circuit and/or 4 ~ 20mA analog interface circuit; Wherein, described MCU control unit adopts ModBUS communication protocol by described RS485 communication interface circuit communication.
7. micro-water gaging transmitter in oil according to any one of claim 1 to 6, it is characterized in that, described MCU control unit comprises:
Filtering processing module, for carrying out moving average filter process to the capacitance measurement signal collected and resistance measuring signals;
Humidity computing module, for calculating humidity value according to the capacitance measurement signal after filtering process;
Temperature computation module, for according to the resistance measuring signals accounting temperature value after filtering process; And
Quality concentration calculation module, for calculating quality concentration according to described humidity value and described temperature value.
8. micro-water gaging transmitter in oil according to claim 7, is characterized in that, described moving average filter process comprises:
Often obtain a sampled value, according to first in first out, N number of sampled value continuous sampling obtained to be placed in a queue and to sort;
Remove maximum sampled value and minimum sampled value;
Arithmetic mean is carried out to a remaining N-2 sampled value, to obtain the data after filtering process;
Wherein, N is fixed number, gets the integer between 50 ~ 100, and described sampled value comprises described capacitance measurement signal and resistance measuring signals.
9. use micro-water gaging transmitter in the oil according to any one of claim 1 to 6 to carry out a method for humiture real time on-line monitoring in oil, it is characterized in that, comprising:
Send a control signal to capacitance measurement circuit;
Gather and represent the capacitance measurement signal of humidity in oil and represent the resistance measuring signals of temperature in oil;
Respectively moving average filter process is carried out to described capacitance measurement signal and resistance measuring signals;
Humidity value is calculated according to the capacitance measurement signal after filtering process;
According to the resistance measuring signals accounting temperature value after filtering process;
Quality concentration is calculated according to described humidity value and described temperature value; And
According to described humidity value and described temperature value produce respectively humidity information output signal and temperature information output signal and exported by output circuit.
10. the method for humiture real time on-line monitoring in oil according to claim 9, it is characterized in that, described moving average filter process comprises:
Often obtain a sampled value, according to first in first out, N number of sampled value continuous sampling obtained to be placed in a queue and to sort;
Remove maximum sampled value and minimum sampled value;
Arithmetic mean is carried out to a remaining N-2 sampled value, to obtain the data after filtering process;
Wherein, N is fixed number, gets the integer between 50 ~ 100, and described sampled value comprises described capacitance measurement signal and resistance measuring signals.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310360278.5A CN104374421A (en) | 2013-08-16 | 2013-08-16 | Transducer for measuring tiny water in oil and method for on-line real-time monitoring of temperature and humidity in oil |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310360278.5A CN104374421A (en) | 2013-08-16 | 2013-08-16 | Transducer for measuring tiny water in oil and method for on-line real-time monitoring of temperature and humidity in oil |
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|---|---|
| CN104374421A true CN104374421A (en) | 2015-02-25 |
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|---|---|---|---|
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| CN (1) | CN104374421A (en) |
Cited By (11)
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| CN104713919A (en) * | 2015-03-04 | 2015-06-17 | 山东电力设备有限公司 | On-line detection device for micro-water content of SF6 gas in transformer bushing |
| CN105203218A (en) * | 2015-09-01 | 2015-12-30 | 中国长江电力股份有限公司 | Upper computer filtering method for generator temperature measuring system |
| CN107091697A (en) * | 2016-02-18 | 2017-08-25 | 中芯国际集成电路制造(上海)有限公司 | Temperature sensor and thermometry, electronic installation based on silicon hole |
| CN108375607A (en) * | 2018-02-26 | 2018-08-07 | 云南电网有限责任公司电力科学研究院 | The method and system of oilpaper part micro-water content in a kind of measurement condenser bushing |
| CN108646804A (en) * | 2018-08-06 | 2018-10-12 | 深圳大图科创技术开发有限公司 | A kind of intelligent greenhouse regulating system |
| CN108983840A (en) * | 2018-08-06 | 2018-12-11 | 深圳源广安智能科技有限公司 | A kind of vehicle interior temperature TT&C system |
| CN109405884A (en) * | 2018-12-03 | 2019-03-01 | 无锡华润矽科微电子有限公司 | The system and method for realization humidity calibration function based on Temperature Humidity Sensor |
| CN109798303A (en) * | 2019-02-26 | 2019-05-24 | 西安交通大学 | A kind of closed bearing lubricating oil state and bearing fault on-line monitoring system |
| CN109900743A (en) * | 2017-12-11 | 2019-06-18 | 圣邦微电子（北京）股份有限公司 | A kind of circuit board soaks detection system |
| CN113465763A (en) * | 2021-07-15 | 2021-10-01 | 中国电子科技集团公司第四十九研究所 | Temperature and humidity sensor and temperature and humidity measuring method |
| CN116203084A (en) * | 2023-02-09 | 2023-06-02 | 广州海谷电子科技有限公司 | Method for realizing humidity-sensitive capacitance sensor based on switch capacitance measurement and sensor |
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Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104713919A (en) * | 2015-03-04 | 2015-06-17 | 山东电力设备有限公司 | On-line detection device for micro-water content of SF6 gas in transformer bushing |
| CN105203218A (en) * | 2015-09-01 | 2015-12-30 | 中国长江电力股份有限公司 | Upper computer filtering method for generator temperature measuring system |
| CN107091697A (en) * | 2016-02-18 | 2017-08-25 | 中芯国际集成电路制造(上海)有限公司 | Temperature sensor and thermometry, electronic installation based on silicon hole |
| CN107091697B (en) * | 2016-02-18 | 2020-05-12 | 中芯国际集成电路制造(上海)有限公司 | Temperature sensor based on through silicon via, temperature measuring method and electronic device |
| CN109900743A (en) * | 2017-12-11 | 2019-06-18 | 圣邦微电子（北京）股份有限公司 | A kind of circuit board soaks detection system |
| CN108375607A (en) * | 2018-02-26 | 2018-08-07 | 云南电网有限责任公司电力科学研究院 | The method and system of oilpaper part micro-water content in a kind of measurement condenser bushing |
| CN108375607B (en) * | 2018-02-26 | 2020-07-07 | 云南电网有限责任公司电力科学研究院 | Method and system for measuring micro-water content of oil paper part in capacitive bushing |
| CN108646804A (en) * | 2018-08-06 | 2018-10-12 | 深圳大图科创技术开发有限公司 | A kind of intelligent greenhouse regulating system |
| CN108983840A (en) * | 2018-08-06 | 2018-12-11 | 深圳源广安智能科技有限公司 | A kind of vehicle interior temperature TT&C system |
| CN109405884A (en) * | 2018-12-03 | 2019-03-01 | 无锡华润矽科微电子有限公司 | The system and method for realization humidity calibration function based on Temperature Humidity Sensor |
| CN109405884B (en) * | 2018-12-03 | 2024-02-27 | 华润微集成电路(无锡)有限公司 | System and method for realizing humidity calibration function based on temperature and humidity sensor |
| CN109798303A (en) * | 2019-02-26 | 2019-05-24 | 西安交通大学 | A kind of closed bearing lubricating oil state and bearing fault on-line monitoring system |
| CN109798303B (en) * | 2019-02-26 | 2020-05-22 | 西安交通大学 | Closed bearing lubricating oil state and bearing fault on-line monitoring system |
| CN113465763A (en) * | 2021-07-15 | 2021-10-01 | 中国电子科技集团公司第四十九研究所 | Temperature and humidity sensor and temperature and humidity measuring method |
| CN113465763B (en) * | 2021-07-15 | 2023-09-05 | 中国电子科技集团公司第四十九研究所 | Temperature and humidity sensor and temperature and humidity measurement method |
| CN116203084A (en) * | 2023-02-09 | 2023-06-02 | 广州海谷电子科技有限公司 | Method for realizing humidity-sensitive capacitance sensor based on switch capacitance measurement and sensor |
| CN116203084B (en) * | 2023-02-09 | 2024-01-23 | 广州海谷电子科技有限公司 | Method for realizing humidity-sensitive capacitance sensor based on switch capacitance measurement and sensor |
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