CN103363886B - The throw sensor gamut temperature compensation of genset and system - Google Patents

Abstract

The invention discloses a full-scale temperature compensation method and system for a swing sensor of a generating set, which adds a full-scale temperature compensation network to the linear correction network of the sensor, and comprehensively compensates the temperature drift of the sensor probe and the electromagnetic parameter temperature of the metal body to be measured. Drift, temperature drift changes caused by displacement-related coupling strength changes, and pre-detector oscillation circuit device temperature drift, etc., solve the technical problem of full-scale temperature compensation of the swing sensor of the generator set, and do not need differential coils. Probe coils of special materials are required to reduce manufacturing costs and have a wide range of applications. For different measured objects, only the relevant parameters of the full-scale temperature compensation network need to be adjusted appropriately to achieve corresponding compensation, so it can be applied to various types of eddy current The full-scale temperature compensation of the sensor has a wide range of practicability.

Description

Full-scale temperature compensation method and system for swing sensor of generating set

technical field

The invention relates to the technical field of generator set monitoring, in particular to a full-scale temperature compensation method for a swing sensor of a generator set.

Background technique

The generator set is the key equipment of the power plant. The operation status of the unit directly affects the safe operation of the power plant. Excessive swing of the generator set shaft is one of the most common faults of the generator set. The large swing directly affects the safe operation of the unit. It is It is an important index to evaluate the operation quality and maintenance quality of the unit. With online swing monitoring, it is possible to evaluate the operating status of the unit in real time and accurately, make maintenance decisions based on the status of the unit, determine the time, content and method of inspection, and predict the remaining service time of the unit to ensure safe and economical operation of the equipment.

At present, eddy current displacement sensors are mainly used to monitor the swing of generator sets on the market. The advantages of this sensor are that it can realize non-contact measurement, high sensitivity, and fast response; but its disadvantage is that it is easily affected by temperature, and with the displacement As the amount increases, the temperature drift increases non-linearly. In order to further improve the measurement accuracy of the eddy current sensor in the full range, full range temperature compensation is required. The working principle of the eddy current sensor is as follows: According to the law of the second, when a high-frequency signal excites the coil in the probe, a high-frequency electromagnetic field is generated. When this magnetic field acts on the metal conductor to be tested, an induced current is formed on the surface of the tested body, and the induced current also generates an alternating magnetic field opposite to the direction of the original magnetic field. Therefore, the superimposition of these two magnetic fields changes the impedance of the probe coil. The equivalent impedance Z after the coil is affected by the conductor is:

In the formula: R1—the real part of the coil impedance, which includes the resistance of the coil, the magnetic loss of the coil and the electrolyte in the skeleton; L1—the inductance of the coil itself; R2—the equivalent resistance of the metal conductor under test, which depends on the eddy current path The geometric size and resistivity of the sensor; L2—the equivalent inductance of the measured metal conductor; M—the mutual inductance coefficient between the coil and the measured conductor, which increases with the shortening of the distance between the sensor coil and the measured object; ω—angular frequency .

It can be seen that the eddy current sensor is the unity of the current-carrying coil and the metal body to be tested, and its temperature stability mainly depends on the following factors: 1) The temperature drift of the electrical characteristics of the sensor probe is mainly reflected in the two factors of probe resistance and inductance. 2) The resistance and inductance loss temperature characteristics of the measured body; 3) The temperature stability of the detection circuit; 4) The temperature drift of the coupling strength between the probe and the measured body.

It can be seen that the factors affected by the temperature of the eddy current displacement sensor include almost all the components and materials of the sensor system. The traditional single parameter temperature compensation can only meet the general requirements. It is difficult to achieve the ideal effect if it is to measure accurately.

In the prior art, in order to further improve the measurement accuracy of the eddy current sensor in the full range, it is generally necessary to perform full-scale temperature compensation; for this type of sensor, there are two main types of traditional temperature compensation methods: probe coil compensation method (such as special material method) , differential coil method) and pre-detector compensation method (such as thermal device method), the following are introduced respectively:

1) Probe coil compensation methods, such as using special materials to manufacture probe coils, using compensation coils (including non-inductive compensation coils) for differential measurement temperature compensation methods, etc., the purpose is to reduce the temperature drift of the probe coil resistance as much as possible. The influence of the temperature drift of the sensor, while the temperature drift of the other factors has not been considered, it cannot reduce the electrical and magnetic characteristic parameters of the metal body under test, the detection circuit, and the eddy current coupling strength related to the displacement of this type of sensor. Various temperature drifts, so full-scale temperature compensation cannot be realized;

2) Pre-detector compensation method, such as output stage thermal element compensation method, which only performs a static compensation value on the output of the sensor that changes with temperature, and does not take into account the eddy current effect temperature of the metal body measured in the use of this type of sensor The degree of drift influence changes with the displacement, and the compensation amount has nothing to do with the displacement, so full-scale temperature compensation cannot be realized.

These traditional temperature compensation methods mainly focus on the compensation of a certain temperature drift factor, without comprehensive consideration of other factors causing temperature drift, and cannot achieve full-scale temperature compensation, resulting in poor monitoring effect of the swing sensor of the generator set.

Contents of the invention

In order to overcome the problem that the traditional temperature compensation method mainly focuses on the compensation of a certain temperature drift factor, and does not comprehensively consider other factors that cause temperature drift, resulting in the poor monitoring effect of the swing sensor of the generator set. The full-range temperature compensation method of the swing sensor of the generating set of the present invention adds a full-range temperature compensation network to the linear correction network of the sensor, comprehensively compensates various temperature drift factors of the sensor, and realizes that the temperature compensation amount changes correspondingly with the displacement change , which solves the technical problem of full-scale temperature compensation of generator set swing sensors, and is suitable for full-scale temperature compensation of various eddy current sensors, and has wide practicability.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A full-scale temperature compensation method for a swing sensor of a generating set, characterized in that: comprising the following steps,

Step (1) Establish a full-scale temperature compensation network for the swing sensor;

Step (2) Install the full-scale temperature compensation network in step (1) in the front detector of the swing sensor of the generator set, and connect it in series with the linear correction network in the front detector to form a new linear correction network;

Step (3) According to the temperature change of the installation environment where the swing sensor is installed, the full-scale temperature compensation network automatically adjusts the resistance value of the network. The new linear correction network established in step (2) uses the nonlinear adjustment characteristics to dynamically change the swing The temperature compensation amount of the corresponding displacement point of the sensor;

Step (4) When the full-scale temperature compensation network of the swing sensor is established in step (1), the output stage temperature compensation network is added to the output stage of the pre-detector, and the power supply of the pre-detector and the The temperature drift of the amplifier circuit is compensated;

Step (5) According to the full-scale temperature influence curve output by the swing sensor, adjust the temperature coefficient of the full-scale temperature compensation network to obtain the temperature drift compensation that basically matches the displacement points of the full-scale, and realize the full-scale temperature compensation.

The aforementioned full-scale temperature compensation method for the swing sensor of the generating set is characterized in that: the establishment of the full-scale temperature compensation network of the swing sensor is obtained by obtaining the linearity correction network of the swing sensor and the nonlinear adjustment network characteristics of the swing sensor. The full-scale output temperature effect characteristic is obtained.

The aforementioned full-scale temperature compensation method for the swing sensor of the generating set is characterized in that: the full-scale temperature compensation network established in the step (1) is formed by parallel connection of the thermal sensor R1 and the potentiometer R2, and the thermal sensor R1 It is a linear positive temperature coefficient thermistor, adjust the resistance value of the potentiometer R2, and change the temperature compensation coefficient of the full-scale temperature compensation network.

The full-range temperature compensation method for the swing sensor of the generating set is characterized in that: the resistance value of the thermal sensor R1 is 200Ω~1kΩ, and the temperature coefficient is 1500~3200PPM/℃; the resistance value of the potentiometer R2 is 1kΩ~10kΩ.

The compensation system for operating the above-mentioned swing sensor full-scale temperature compensation method of the generator set includes a swing sensor probe coil, a front detector and a monitoring target generator set shaft, and the swing sensor probe coil is non-contact collected by the eddy current effect The swing amount of the rotating shaft of the generator set, the output end of the probe coil of the swing sensor performs full-scale temperature compensation through the pre-detector, and the pre-detector includes a linear correction network, an oscillator, a detector, a filter, and an output stage temperature compensation Network and amplifying circuit, the probe coil of the swing sensor is respectively connected with the detector and the linear correction network through the oscillator, and the linear correction network is connected with a sensing system for matching each displacement point of the full range with the rotating shaft of the generator set A full-scale temperature compensation network for temperature drift compensation, the detector is connected to the input end of the output stage temperature compensation network through a filter, and the output end of the output stage temperature compensation network is connected to the amplifier circuit.

The aforementioned full-scale temperature compensation system for the swing sensor of the generating set is characterized in that: the full-scale temperature compensation network is formed by parallel connection of a thermal sensor R1 and a potentiometer R2, and the thermal sensor R1 is a linear positive temperature coefficient thermal sensor. Sensitive resistance, adjust the resistance of the potentiometer R2, change the temperature compensation coefficient of the full-scale temperature compensation network.

The full range temperature compensation system of the swing sensor of the generating set is characterized in that: the resistance of the thermal sensor R1 is 200Ω~1kΩ, and the temperature coefficient is 1500~3200PPM/℃; the resistance of the potentiometer R2 is 1kΩ~10kΩ.

The beneficial effect of the present invention is: the full-scale temperature compensation method of the swing sensor of the generating set of the present invention adds a full-scale temperature compensation network to the linearity correction network of the sensor, and comprehensively compensates the temperature drift of the sensor probe and the electromagnetic force of the metal body under test. Parameter temperature drift, temperature drift changes caused by displacement-related coupling strength changes, and temperature drift of pre-detector oscillation circuit components solve the technical problem of full-scale temperature compensation for generator set swing sensors, and do not require differential coils , does not require probe coils of special materials, reduces manufacturing costs, and has a wide range of applications. For different measured objects, only need to adjust the relevant parameters of the full-scale temperature compensation network to achieve corresponding compensation, so it can be applied to various The full-scale temperature compensation of the eddy current sensor has a wide range of practicability.

Description of drawings

Fig. 1 is a flow chart of the full-scale temperature compensation method for the swing sensor of the generator set according to the present invention.

Fig. 2 is a system block diagram of the swing sensor full-scale temperature compensation system of the generator set according to the present invention.

Fig. 3 is a schematic circuit diagram of the swing sensor full-scale temperature compensation system of the generator set of the present invention.

Fig. 4 is a schematic circuit diagram of the full-scale temperature compensation network of the generator set of the present invention.

detailed description

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

The full-scale temperature compensation method of the swing sensor of the generating set of the present invention comprises the following steps,

The first step is to obtain the nonlinear adjustment characteristics of the linear correction network of the swing sensor to the output voltage and the influence characteristics of the full-scale output temperature of the swing sensor. According to the nonlinear adjustment characteristics of the linear correction network and the influence characteristics of the full-scale output temperature, the swing Full range temperature compensation network of the sensor;

In the second step, the full-scale temperature compensation network is installed in the front detector of the swing sensor of the generator set, and connected in series with the linear correction network in the front detector to form a new linear correction network;

In the third step, according to the temperature change of the installation environment where the pendulum sensor is installed, the full-scale temperature compensation network automatically adjusts the resistance value of the network, and the new linear correction network established dynamically changes the corresponding displacement point of the pendulum sensor by using the nonlinear adjustment characteristics. temperature compensation;

In the fourth step, while establishing the full-scale temperature compensation network of the swing sensor, the output stage temperature compensation network is added to the output stage of the pre-detector, and the power supply of the pre-detector and the amplifier circuit in the pre-detector are improved. Compensate for temperature drift;

In the fifth step, according to the full-scale temperature influence curve output by the swing sensor, by properly adjusting the temperature coefficient of the full-scale temperature compensation network, the temperature drift compensation that basically matches the full-scale displacement points is obtained, and the full-scale temperature compensation is realized.

As shown in Figure 2, the compensation system for operating the above-mentioned swing sensor full-scale temperature compensation method of the generator set includes a swing sensor probe coil 8, a pre-detector, and a metal body 9 to be tested composed of the rotating shaft of the monitoring target generator set The swing sensor probe coil 8 non-contactly collects the swing amount of the metal body 9 to be tested through the eddy current effect, and the output end of the swing sensor probe coil 8 performs full-scale temperature compensation through the pre-detector, and the pre-detector includes linear correction Network 2, oscillator 3, detector 4, filter 5, output stage temperature compensation network 6 and amplifying circuit 7, the swing sensor probe coil 8 is connected to detector 4 and linearity correction network 2 respectively through oscillator 3 , the linear correction network 2 is connected with a sensor system temperature drift compensation for matching each displacement point of the full scale with the metal body to be tested. The full scale temperature compensation network 1, the detector 4 is connected with the output stage temperature compensation network through a filter 5 6 is connected to the input end, and the output stage temperature compensation network 6 is connected to the amplifier circuit 7. Compared with the existing pre-detector, it increases the full-scale temperature at the back end of the linear correction network 2 of the pre-detector The compensation network 1, and the linear correction network 2 is the negative feedback network of the oscillator 3, which can synthesize the temperature drift of the probe coil 8 of the swing sensor, the temperature drift of the electromagnetic parameter of the rotating shaft of the generator set, that is, the metal body 9 to be measured, and the displacement-related There are various factors such as temperature drift changes due to changes in coupling strength and temperature drift of the pre-detector oscillator 3 . As the temperature rises, the resistance value of the full-scale temperature compensation network 1 increases, and then the resistance value of the linear correction network 2 is changed, and the temperature compensation amount of the corresponding displacement point is dynamically changed by using the nonlinear adjustment characteristics of the linear correction network. Appropriate adjustment can obtain the temperature drift compensation of the sensor system matching the measured body at each displacement point in the full range, thereby realizing full-scale temperature compensation, and the output stage temperature compensation network 6 can correct the temperature drift and amplify The temperature drift of the circuit 7 is compensated to improve the detection accuracy of the swing of the rotating shaft of the generating set.

As shown in Figure 3, the circuit schematic diagram of the swing sensor full-scale temperature compensation system of the generator set of the present invention includes a full-scale temperature compensation network I, a linearity correction network II, an oscillator III, a detector IV, a filter V, The output stage temperature compensation network VI and the amplifier circuit VII, wherein the full-scale temperature compensation network I is connected in series with the correction resistor R4 in the linear correction network II to form a new linear correction network II, which is a part of the negative feedback network of the oscillator III. The characteristic of the linear correction network II is that when the resistance increases, the negative feedback of the oscillator increases, and the output voltage of the swing sensor decreases nonlinearly; and when the resistance of the linear correction network II decreases, the negative feedback of the oscillator III weakens, The output voltage of the swing sensor increases nonlinearly; the output of the swing sensor changes due to the temperature drift of various parameters. When the temperature drift increases, the output increases nonlinearly with the increase of displacement, which is equivalent to a linear correction network The resistance decreases; when the temperature decreases, the output decreases nonlinearly with the increase of the displacement, which is equivalent to the increase of the resistance of the linear correction network; combined with the above characteristics, when the temperature drift increases, by increasing the I resistance of the full-scale temperature compensation network Larger, the resistance of the linear correction network II increases; on the contrary, when the temperature decreases, the resistance of the linear correction network II decreases by reducing the resistance of the full-scale temperature compensation network I; properly adjust the temperature compensation coefficient of the full-scale temperature compensation network , the temperature drift of each displacement point of the sensor can be compensated to realize full-scale temperature compensation.

The schematic diagram of the full-range temperature compensation network circuit shown in Figure 4 is composed of a linear positive temperature coefficient thermistor R1 and a temperature compensation coefficient adjustment potentiometer R2 in parallel, and the temperature coefficient of the thermal sensor R1 can be 1500PPM/℃. The linear positive temperature coefficient thermistor has a resistance of 200Ω~1kΩ, preferably 470Ω, and the resistance of the potentiometer R2 is 1kΩ~10kΩ, preferably 2kΩ. The thermistor R1 is connected in parallel with the potentiometer R2, and different temperature coefficients can be adjusted through the potentiometer R2 to achieve more appropriate temperature compensation. The compensation process is as follows. When the temperature rises, on the one hand, the output of the sensor increases nonlinearly with the increase of displacement; on the other hand, the resistance value of R1 increases, and the resistance value of the full-scale temperature compensation network composed of R1 and R2 connected in parallel corresponds to Increase, the resistance of the entire linear correction network increases, so that the sensor output decreases nonlinearly with the increase of displacement; when the temperature decreases, its action process is reversed; therefore, through appropriate adjustment of the temperature compensation coefficient, it can be greatly weakened or even Basically offset the output temperature drift of each displacement point of the sensor, so as to achieve the full-scale temperature compensation effect. This full-scale temperature compensation network is combined with the output stage temperature compensation network of the pre-detector, which can control the temperature drift coefficient of each displacement point of the full-scale sensor within a lower range of 0.05%/℃.

In summary, the full-range temperature compensation method for the swing sensor of the generator set of the present invention adds a full-range temperature compensation network to the linear correction network of the sensor, and comprehensively compensates the temperature drift of the sensor probe and the electromagnetic parameter temperature of the metal body to be measured. Drift, temperature drift changes caused by displacement-related coupling strength changes, and temperature drift of pre-detector oscillation circuit components solve the technical problem of full-scale temperature compensation for generator set swing sensors, and do not require differential coils. Probe coils of special materials are required to reduce manufacturing costs and have a wide range of applications. For different measured objects, only the relevant parameters of the full-scale temperature compensation network need to be adjusted appropriately to achieve corresponding compensation, so it can be applied to various types of eddy current The full-scale temperature compensation of the sensor has a wide range of practicability.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (4)

1. The full-scale temperature compensation method of the swing sensor of the generating set is characterized in that: comprising the following steps, Step (1) Establish a full-scale temperature compensation network for the swing sensor; Step (2) Install the full-scale temperature compensation network in step (1) in the front detector of the swing sensor of the generator set, and connect it in series with the linear correction network in the front detector to form a new linear correction network; Step (3) According to the temperature change of the installation environment where the pendulum sensor is located, the full-scale temperature compensation network automatically adjusts the resistance value of the network. The new linear correction network established in step (2) uses the nonlinear adjustment characteristics to dynamically change the pendulum The temperature compensation amount of the corresponding displacement point of the degree sensor; Step (4) When the full-scale temperature compensation network of the swing sensor is established in step (1), the output stage temperature compensation network is added to the output stage of the pre-detector, and the power supply of the pre-detector and the The temperature drift of the amplifier circuit is compensated; Step (5) According to the full-scale temperature influence curve output by the swing sensor, adjust the temperature coefficient of the full-scale temperature compensation network to obtain a temperature drift compensation that basically matches the full-scale displacement points, and realize full-scale temperature compensation; The establishment of the full-scale temperature compensation network of the swing sensor is obtained by obtaining the nonlinear adjustment network characteristics of the linear correction network of the swing sensor and the full-scale output temperature influence characteristics of the swing sensor; The full-scale temperature compensation network established in the step (1) is composed of a thermal sensor R1 and a potentiometer R2 connected in parallel. The thermal sensor R1 is a linear positive temperature coefficient thermistor. Adjust the resistance of the potentiometer R2 to change The temperature compensation coefficient of the full-scale temperature compensation network; The resistance value of the thermal sensitive device R1 is 200Ω~1kΩ, and the temperature coefficient is 1500~3200PPM/°C; the resistance value of the potentiometer R2 is 1kΩ~10kΩ. 2. The compensation system for operating the full-scale temperature compensation method of the swing sensor of the generating set according to claim 1, characterized in that: it comprises a swing sensor probe coil (8), a pre-detector, and a rotating shaft of the monitoring target generating set The metal body (9) to be tested; the swing sensor probe coil (8) collects the swing amount of the rotating shaft of the generator set non-contact through the eddy current effect, and the output end of the swing sensor probe coil (8) is detected by the front The detector performs full-scale temperature compensation; the pre-detector includes a linear correction network (2), an oscillator (3), a detector (4), a filter (5), an output stage temperature compensation network (6) and an amplifier circuit (7); the pendulum sensor probe coil (8) is connected to the detector (4) and the linear correction network (2) respectively through the oscillator (3); the linear correction network (2) is connected to be used for the whole The full-scale temperature compensation network (1) for temperature drift compensation of the sensing system matched with each displacement point of the measuring range and the metal body (9) to be measured, the detector (4) is connected with the temperature compensation network of the output stage through the filter (5) The input ends of (6) are connected, and the output end of the output stage temperature compensation network (6) is connected with the amplifier circuit (7). 3. The full-scale temperature compensation system of the swing sensor of the generator set according to claim 2, characterized in that: the full-scale temperature compensation network (1) is formed by parallel connection of a thermal sensor R1 and a potentiometer R2, and the The thermistor R1 is a linear positive temperature coefficient thermistor, adjust the resistance of the potentiometer R2, and change the temperature compensation coefficient of the full-scale temperature compensation network. 4. The full-scale temperature compensation system for the swing sensor of the generator set according to claim 2, wherein the resistance of the thermal sensor R1 is 200Ω~1kΩ, and the temperature coefficient is 1500~3200PPM/°C; The resistance value of the potentiometer R2 is 1kΩ~10kΩ.