Oil-micro-water analyzer and control method thereof

Abstract

The invention discloses an oil micro-water analyzer, belonging to the technical field of oil micro-water analyzers; the technical problem to be solved is: to provide an improvement on the hardware structure of an oil micro-water analyzer; the technical scheme adopted to solve the above technical problem is: comprising a shell and a microcontroller, a power module, and a motor control module arranged in the shell, the power supply end of the microcontroller is connected to the power module through a wire, and the microcontroller is also connected to the motor control module through a wire; a humidity sensor is also arranged on the side of the shell; the motor control module comprises a motor controller connected to the microcontroller through a wire, and a circuit board of the motor control module comprises a motor main circuit and a control circuit, and the motor main circuit realizes on-off control of the motor by arranging a contactor KM1 and the control circuit; the invention is applied to the detection of moisture in transformer insulating oil.

Description

Technical Field

[0001] The invention discloses an oil-micro-water analyzer and a control method thereof, belonging to the technical field of oil-micro-water analyzers and control methods thereof. Background Art

[0002] Transformer insulating oil has the functions of insulation, corrosion prevention and heat dissipation during transformer operation. With the long-term operation of the transformer, due to some objective or subjective factors, some water will be mixed into the insulating oil. The presence of these trace amounts of water will greatly reduce the insulation performance of the insulating oil, accelerate insulation aging, and may also cause partial discharge breakdown and bubble generation in the transformer, which not only seriously shortens the normal service life of the transformer, but may even lead to some accidents in serious cases, causing huge property losses and personal injuries. Therefore, the transformer must be tested for micro-water before it is put into operation or after a certain period of operation to prevent the micro-water from exceeding the standard.

[0003] The main methods for measuring micro-water in transformer insulating oil are: distillation method, Karl-Fischer method, weight method and dielectric constant method. Considering the accuracy, speed and environmental protection of the test, the dielectric constant method is currently widely used. The basic principle of dielectric constant is: the dielectric constant of transformer oil is determined by the different dielectric constants of oil and water in the transformer oil. The amount of water in the oil determines the dielectric constant of the transformer oil. The sensor is a capacitive temperature sensor or humidity sensor. The sensor is immersed in oil. The change of dielectric constant leads to the change of capacitance. The change of capacitance is measured and calculated to obtain the micro-water content. The control method of the existing oil micro-water analyzer is as follows: Figure 1 As shown, there are the following problems in daily use:

[0004] (1) Drying of the measuring chamber requires manual intervention, and the measuring chamber needs to be dried by controlling the drying motor;

[0005] (2) The drying process is laborious and inefficient. The drying motor in the measuring chamber is controlled by a momentary switch. Oil testers usually need to press the RESET button for more than 20 minutes to reduce the ppm of water in the measuring chamber to the required level. This is inefficient and is a great test of the patience and physical strength of oil testers.

[0006] (3) The reliability of the momentary switch is poor. In daily use, due to the different pressing forces of different laboratory personnel, the momentary switch used for the RESET button is often damaged, and it is relatively troublesome to replace.

[0007] Therefore, it is necessary to provide an oil micro-water analyzer and a control method thereof that can realize one-key operation of the entire process of transformer insulating oil micro-water analysis. Summary of the invention

[0008] In order to overcome the deficiencies in the prior art, the present invention aims to solve the technical problem of providing an improvement in the hardware structure of an oil-micro-water analyzer and an improvement in its control method.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: an oil micro-water analyzer, used for detecting moisture in transformer insulating oil, comprising a housing and a microcontroller, a power module, and a motor control module arranged in the housing, wherein the power supply end of the microcontroller is connected to the power module through a wire, and the microcontroller is also connected to the motor control module through a wire, for controlling the speed of the motor;

[0010] The front of the housing is provided with a touch screen for displaying the micro-water content in the transformer insulating oil, and the side of the housing is provided with a conduit for collecting and placing oil samples, the conduit is connected to the oil sample bottle mouth through a pipeline, and an oil pump is provided on the pipeline;

[0011] A humidity sensor for collecting micro-water data in the measuring chamber is also provided on the side of the housing;

[0012] The control end of the oil pump is connected to the microcontroller through a wire, and the touch screen and the humidity sensor are respectively connected to the microcontroller through wires;

[0013] The motor control module includes a motor controller connected to a microcontroller via a wire. The circuit board of the motor control module includes a motor main circuit and a control circuit. The motor main circuit realizes on-off control of the motor by setting a contactor KM1 and a control circuit.

[0014] The front side of the housing is also provided with a power button and a measuring button, and the power button and the measuring button are connected to the microcontroller through respective wires.

[0015] The power supply inlet of the main circuit of the motor is provided with fuses FU1 and FU2 for overcurrent protection. The fuses FU1 and FU2 are respectively connected to the normally open contact KM1.1 of the contactor KM1 through wires. The normally open contact KM1.1 is connected to the power supply end of the motor after being connected in series with the thermal relay FR1 through wires.

[0016] The power supply terminal VCC of the control loop is connected in parallel with one end of the adjustable resistor R1, one end of the resistor R3, the positive power supply terminal of the amplifier A1, and one end of the resistor R4 through a wire; the other end of the adjustable resistor R1 is connected in parallel with one end of the resistor R2 and the in-phase input terminal of the amplifier A1 through a wire; the other end of the resistor R3 is connected in parallel with one end of the humidity-sensitive resistor Rh1 and the inverting input terminal of the amplifier A1; the output end of the amplifier A1 is connected in parallel with the other end of the resistor R4, and then connected in series with the fuse FU1 and the coil KM1.2 of the contactor KM1, and then grounded;

[0017] The other end of the resistor R2, the other end of the humidity-sensitive resistor Rh1, and the negative electrode of the power supply of the amplifier A1 are grounded through a wire.

[0018] The amplifier A1 is specifically a voltage comparison amplifier of model LM339, and the adjustable resistor R1 is arranged at the non-inverting input terminal of the amplifier A1 to adjust the reference voltage of the non-inverting input terminal of the amplifier A1.

[0019] The humidity-sensitive resistor Rh1 is specifically a humidity-sensitive resistor whose resistance decreases as the humidity increases.

[0020] A control method for an oil-micro-water analyzer comprises the following steps:

[0021] Step 1: Press the power button to start the oil micro-water analyzer. The microcontroller controls the humidity sensor to collect the micro-water content in the measuring chamber and analyzes and determines whether the micro-water ppm value in the measuring chamber is within the set value. When the micro-water ppm value in the measuring chamber exceeds the set value, proceed to step 2. When the micro-water ppm value in the measuring chamber is less than the set value, proceed to step 3.

[0022] Step 2: The motor control module controls the circuit board to output high voltage, the control circuit is energized, the normally open contact KM1.1 is closed, and the motor is started to dry the measuring chamber;

[0023] Step 3: The control circuit is not energized, the normally open contact KM1.1 is not closed, the motor is not started, and the microcontroller 1 controls the touch screen to display a prompt to inject the oil sample. The microcontroller 1 controls the oil pump to inject the oil sample in the oil sample bottle into the catheter. Press the measurement key to start the oil sample micro-water analysis. After the analysis is completed, the measurement result is displayed on the touch screen, and then the oil sample in the catheter is discharged;

[0024] Step 4: After the oil sample is discharged, determine whether to perform the next analysis based on the measurement results of step 3. If the next analysis is required, directly go to the steps after powering on in step 1;

[0025] Step 5: After the measurement is completed, press the power button to shut down the oil-water analyzer.

[0026] The setting value of the micro-water ppm value in the measuring chamber in the step 1 is 5. When the ppm value = 5, the resistance in the control loop satisfies R1: R2 = R3: Rh1, and the resistance value of the adjustable resistor R1 is set according to the above formula.

[0027] The beneficial effects of the present invention compared with the prior art are as follows:

[0028] (1) Whether the oil-micro-water analysis measurement chamber needs to be dried no longer requires manual judgment and operation. By setting a humidity sensor on the analyzer to collect the micro-water data in the measurement chamber and making a judgment through a microcontroller, automatic control is achieved;

[0029] (2) The inching mechanical switch that controls the start and stop of the drying motor is replaced with an electromagnetic relay, which has higher reliability and longer service life;

[0030] (3) Drying of the measuring chamber no longer requires long-term manual pressing, which reduces the workload of oil testers and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings:

[0032] Figure 1 It is a flow chart of the control method of oil and water in the prior art;

[0033] Figure 2 It is a structural schematic diagram of the oil-micro-water analyzer of the present invention;

[0034] Figure 3 A control circuit diagram of the main circuit of the drying motor of the present invention;

[0035] Figure 4 is a control circuit diagram of the contactor of the present invention;

[0036] Figure 5 It is a schematic diagram of the circuit structure of the present invention;

[0037] Figure 6 This is a flow chart of the oil-micro-water control method of the present invention.

[0038] In the figure: 1 is a microcontroller, 2 is a power module, 3 is a motor control module, 4 is a touch screen, 5 is a catheter, 6 is a humidity sensor, 7 is a power button, 8 is a measurement button, and 9 is a motor. DETAILED DESCRIPTION

[0039] like Figures 1 to 6 As shown, the present invention is an oil micro-water analyzer, which is used for detecting moisture in transformer insulating oil, and includes a housing and a microcontroller 1, a power module 2, and a motor control module 3 arranged in the housing. The power supply end of the microcontroller 1 is connected to the power module 2 through a wire, and the microcontroller 1 is also connected to the motor control module 3 through a wire, and is used to control the speed of the motor 9;

[0040] The front of the housing is provided with a touch screen 4 for displaying the micro-water content in the transformer insulating oil, and the side of the housing is provided with a conduit 5 for collecting and placing oil samples, the conduit 5 is connected to the oil sample bottle mouth through a pipeline, and an oil pump 10 is provided on the pipeline;

[0041] The side of the housing is also provided with a humidity sensor 6 for collecting micro-water data of the measuring chamber;

[0042] The control end of the oil pump 10 is connected to the microcontroller 1 through a wire, and the touch screen 4 and the humidity sensor 6 are connected to the microcontroller 1 through wires respectively;

[0043] The motor control module 3 includes a motor controller connected to the microcontroller 1 through a wire. The circuit board of the motor control module 3 includes a motor main circuit and a control circuit. The motor main circuit realizes on-off control of the motor 9 by setting a contactor KM1 and a control circuit.

[0044] The front side of the housing is also provided with a power button 7 and a measuring button 8, and the power button 7 and the measuring button 8 are connected to the microcontroller 1 through respective wires.

[0045] The power supply inlet of the main circuit of the motor is provided with fuses FU1 and FU2 for overcurrent protection. The fuses FU1 and FU2 are respectively connected to the normally open contact KM1.1 of the contactor KM1 through wires. The normally open contact KM1.1 is connected to the power supply end of the motor 9 after being connected in series with the thermal relay FR1 through a wire.

[0046] The power supply terminal VCC of the control loop is connected in parallel with one end of the adjustable resistor R1, one end of the resistor R3, the positive power supply terminal of the amplifier A1, and one end of the resistor R4 through a wire; the other end of the adjustable resistor R1 is connected in parallel with one end of the resistor R2 and the in-phase input terminal of the amplifier A1 through a wire; the other end of the resistor R3 is connected in parallel with one end of the humidity-sensitive resistor Rh1 and the inverting input terminal of the amplifier A1; the output end of the amplifier A1 is connected in parallel with the other end of the resistor R4, and then connected in series with the fuse FU1 and the coil KM1.2 of the contactor KM1, and then grounded;

[0047] The other end of the resistor R2, the other end of the humidity-sensitive resistor Rh1, and the negative electrode of the power supply of the amplifier A1 are grounded through a wire.

[0048] The amplifier A1 is specifically a voltage comparison amplifier of model LM339, and the adjustable resistor R1 is arranged at the non-inverting input terminal of the amplifier A1 to adjust the reference voltage of the non-inverting input terminal of the amplifier A1.

[0049] The humidity-sensitive resistor Rh1 is specifically a humidity-sensitive resistor whose resistance decreases as the humidity increases.

[0050] A control method for an oil-micro-water analyzer comprises the following steps:

[0051] Step 1: Press the power button 7 to start the oil micro-water analyzer, and the microcontroller 1 controls the humidity sensor 6 to collect the micro-water content in the measuring chamber and analyze and determine whether the micro-water ppm value in the measuring chamber is within the set value. When the micro-water ppm value in the measuring chamber exceeds the set value, go to step 2; when the micro-water ppm value in the measuring chamber is less than the set value, go to step 3;

[0052] Step 2: The motor control module 3 controls the circuit board to output high voltage, the control circuit is energized, the normally open contact KM1.1 is closed, and the motor 9 is started to dry the measuring chamber;

[0053] Step 3: The control circuit is not energized, the normally open contact KM1.1 is not closed, the motor 9 is not started, and the microcontroller 1 controls the touch screen 4 to display a prompt to inject the oil sample. The microcontroller 1 controls the oil pump 10 to inject the oil sample in the oil sample bottle into the conduit 5. Press the measurement key 8 to start the oil sample micro-water analysis. After the analysis is completed, the measurement result is displayed on the touch screen 4, and then the oil sample in the conduit 5 is discharged;

[0054] Step 4: After the oil sample is discharged, determine whether to perform the next analysis based on the measurement results of step 3. If the next analysis is required, directly go to the steps after powering on in step 1;

[0055] Step 5: After the measurement is completed, press the power button 7 to shut down the oil-water analyzer.

[0056] The setting value of the ppm value of the micro-water in the measuring chamber in the step 1 is 5. When the ppm value = 5, the resistance in the control loop satisfies R1: R2 = R3: Rh1, and the resistance value of the adjustable resistor R1 is set according to the above formula.

[0057] The oil-water analyzer provided by the present invention eliminates the original inching switch and electromagnetic contactor for controlling the start and stop of the drying motor, and connects a fuse FU2, a thermal relay FR1 and a group of contactor normally open contacts KM1.1 in series in the motor circuit. Figure 3 As shown, fuse FU2 is used for overcurrent protection, thermal relay FR1 is used for motor overload protection, and contactor KM1 is used to switch the drying motor on and off. Figure 4 As shown, R1 is an adjustable resistor, which is used to adjust 1 / 4 of the reference voltage of the non-inverting input terminal of LM339, and Rh1 is a humidity sensitive resistor, whose resistance decreases as the humidity increases. The resistance of resistor R1 is adjusted so that when the measurement room ppm=5, the resistance satisfies the relationship R1: R2=R3: Rh1, and the resistance of R1 that meets the condition is set at this time. Therefore, when the water content in the measuring room is ppm<5, the humidity in the measuring room is low. At this time, the resistance of the humidity-sensitive resistor Rh1 increases, and the voltage at the non-inverting input terminal of the amplifier A1 is less than the voltage at the inverting input terminal. At this time, the output of the amplifier A1 is zero, the contactor coil KM1.2 is not energized, and the drying motor does not start; when the water content in the measuring room is ppm>5, the humidity in the measuring room is high. At this time, the resistance of the humidity-sensitive resistor Rh1 decreases, and the voltage at the non-inverting input terminal of the amplifier A1 is greater than the voltage at the inverting input terminal. At this time, the amplifier A1 outputs a high voltage under the action of the pull-up resistor R4, and the contactor KM1 coil KM1.2 is energized through the fuse FU1, and the drying motor 9 starts.

[0058] The control process of the oil-water analyzer of the present invention is as follows: Figure 5 As shown. After the analyzer is turned on, the micro-water content of the measuring chamber is first detected, and the humidity data of the measuring chamber is collected through the humidity sensor 6. The microcontroller 1 determines the size of the micro-water content of the measuring chamber through analysis; when the micro-water content ppm>5, the control circuit board outputs high voltage, the relay control circuit is energized, the contactor normally open contact KM1.1 is closed, and the drying motor 9 is started to dry the measuring chamber; when the micro-water content of the measuring chamber ppm<5, the contactor control circuit is not energized, the normally open contact KM1.1 remains in the original state and is not closed, and the drying motor 9 is not started at this time. The analyzer touch screen 4 displays a prompt to inject the oil sample, and the microcontroller 1 controls the oil pump 10 to start and inject the oil sample into the conduit 5. After the oil sample is injected, press the measurement, 8 to start the oil sample micro-water analysis, and the analysis result is automatically displayed on the touch screen 4 after the analysis is completed. Then, the oil sample is discharged and waits for the next analysis or shut down.

[0059] What needs to be explained about the specific structure of the present invention is that the connection relationship between the various component modules adopted in the present invention is definite and feasible. Except for the special instructions in the embodiments, the specific connection relationship can bring about the corresponding technical effects, and solve the technical problems raised by the present invention without relying on the execution of the corresponding software program. Except for the specific instructions, the models and connection methods of the components, modules and specific components appearing in the present invention belong to the existing technologies such as published patents, published journal articles, or common knowledge that can be obtained by technical personnel in this field before the application date, and there is no need to elaborate, so that the technical solution provided in this case is clear, complete and feasible, and the corresponding physical products can be reproduced or obtained according to the technical means.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method of an oil micro-water analyzer, using the oil micro-water analyzer for detecting moisture in transformer insulating oil, characterized in that: The oil-micro-water analyzer comprises a housing and a microcontroller (1), a power module (2), and a motor control module (3) arranged in the housing, wherein the power supply end of the microcontroller (1) is connected to the power module (2) via a wire, and the microcontroller (1) is also connected to the motor control module (3) via a wire for controlling the rotation speed of the motor (9); The front of the housing is provided with a touch screen (4) for displaying the micro-water content in the transformer insulating oil, and the front of the housing is also provided with a power on / off key (7) and a measuring key (8), wherein the power on / off key (7) and the measuring key (8) are connected to the microcontroller (1) via respective wires; A conduit (5) for collecting and placing oil samples is provided on the side of the housing, the conduit (5) is connected to the mouth of the oil sample bottle via a pipeline, and an oil pump (10) is provided on the pipeline; A humidity sensor (6) for collecting micro-water data in the measuring chamber is also provided on the side of the housing; the control end of the oil pump (10) is connected to the microcontroller (1) via a wire, and the touch screen (4) and the humidity sensor (6) are respectively connected to the microcontroller (1) via wires; The motor control module (3) comprises a motor controller connected to the microcontroller (1) via a wire, the circuit board of the motor control module (3) comprises a motor main circuit and a control circuit, and the motor main circuit realizes on-off control of the motor (9) by arranging a contactor KM1 and the control circuit; A fuse FU1 and a fuse FU2 for overcurrent protection are arranged on the power supply line end of the main circuit of the motor, and the fuse FU1 and the fuse FU2 are respectively connected to the normally open contact KM1.1 of the contactor KM1 through a wire, and the normally open contact KM1.1 is connected to the power supply end of the motor (9) after being connected in series with the thermal relay FR1 through a wire; The power supply terminal VCC of the control loop is connected in parallel with one end of the adjustable resistor R1, one end of the resistor R3, the positive power supply terminal of the amplifier A1, and one end of the resistor R4 through a wire; the other end of the adjustable resistor R1 is connected in parallel with one end of the resistor R2 and the in-phase input terminal of the amplifier A1 through a wire; the other end of the resistor R3 is connected in parallel with one end of the humidity-sensitive resistor Rh1 and the inverting input terminal of the amplifier A1; the output end of the amplifier A1 is connected in parallel with the other end of the resistor R4, and then connected in series with the fuse FU1 and the coil KM1.2 of the contactor KM1, and then grounded; The other end of the resistor R2, the other end of the humidity-sensitive resistor Rh1, and the negative electrode of the power supply of the amplifier A1 are grounded through a wire; The control method comprises the following steps: Step 1: Press the power button (7) to start the oil micro-water analyzer, and the microcontroller (1) controls the humidity sensor (6) to collect the micro-water content in the measuring chamber and analyze and determine whether the micro-water ppm value in the measuring chamber is within the set value. When the micro-water ppm value in the measuring chamber exceeds the set value, the process proceeds to step 2; when the micro-water ppm value in the measuring chamber is less than the set value, the process proceeds to step 3; The setting value of the micro-water ppm value in the measuring chamber in step 1 of the control method of the oil micro-water analyzer is 5. When the ppm value = 5, the resistance in the control loop satisfies R1: R2 = R3: Rh1, and the resistance value of the adjustable resistor R1 is set according to the above formula; Step 2: The motor control module (3) controls the circuit board to output high voltage, the control circuit is energized, the normally open contact KM1.1 is closed, and the motor (9) is started to dry the measuring chamber; Step 3: The control circuit is not energized, the normally open contact KM1.1 is not closed, the motor (9) is not started, and at the same time the microcontroller (1) controls the touch screen (4) to display a prompt to inject the oil sample. The microcontroller (1) controls the oil pump (10) to inject the oil sample in the oil sample bottle into the conduit (5). The measurement key (8) is pressed to start the oil sample micro-water analysis. After the analysis is completed, the measurement result is displayed on the touch screen (4), and then the oil sample in the conduit (5) is discharged; Step 4: After the oil sample is discharged, determine whether to perform the next analysis based on the measurement results of step 3. If the next analysis is required, directly go to the steps after powering on in step 1; Step 5: After the measurement is completed, press the power button (7) to shut down the oil-water analyzer.

2. The control method of an oil-micro-water analyzer according to claim 1, characterized in that: The amplifier A1 is specifically a voltage comparison amplifier of model LM339, and the adjustable resistor R1 is arranged at the non-inverting input terminal of the amplifier A1 to adjust the reference voltage of the non-inverting input terminal of the amplifier A1.

3. The control method of an oil-micro-water analyzer according to claim 2, characterized in that: The humidity-sensitive resistor Rh1 is specifically a humidity-sensitive resistor whose resistance decreases as the humidity increases.

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