阅读说明：本技术 全光纤无源带电体温度监测方法及装置 (All-fiber passive charged body temperature monitoring method and device ) 是由 王晗 张茹 张梦营 于 2021-09-22 设计创作，主要内容包括：本申请公开了一种全光纤无源带电体温度监测方法及装置。该方法可以包括：确定全光纤无源带电体的触头位置与多个监测点位置；确定多个接触电阻,分别确定每一个接触电阻的参量；将每一个接触电阻连接全光纤无源带电体,通电后测量触头位置与多个监测点位置的温度；建立触头位置与多个监测点位置的温度的拟合关系,通过拟合关系计算触头位置的温度。本发明能够实时监测带电体温度数据,可有效避免人工巡检带来的效率低,漏检,信息孤岛等缺点,实现带电体温度监测一体化,信息化建设。(The application discloses a method and a device for monitoring the temperature of an all-fiber passive charged body. The method can comprise the following steps: determining the contact position and a plurality of monitoring point positions of an all-fiber passive charged body; determining a plurality of contact resistances, and respectively determining parameters of each contact resistance; connecting each contact resistor with an all-fiber passive charged body, and measuring the temperature of the contact position and the positions of a plurality of monitoring points after electrifying; and establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions, and calculating the temperature of the contact position through the fitting relation. The invention can monitor the temperature data of the charged body in real time, can effectively avoid the defects of low efficiency, missing detection, information island and the like caused by manual inspection, and realizes the integration and information construction of the temperature monitoring of the charged body.)

1. A method for monitoring the temperature of an all-fiber passive charged body is characterized by comprising the following steps:

determining the contact position and a plurality of monitoring point positions of an all-fiber passive charged body;

determining a plurality of contact resistances, and respectively determining parameters of each contact resistance;

connecting each contact resistor with the all-fiber passive electrified body, and measuring optical signals of the contact position and the positions of a plurality of monitoring points after electrifying;

converting optical signals of the contact position and the plurality of monitoring point positions into electric signals, and further determining the temperature of the contact position and the plurality of monitoring point positions;

and establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions, and calculating the temperature of the contact position according to the fitting relation.

2. The all-fiber passive charged body temperature monitoring method according to claim 1, wherein the parameters of the contact resistance are:

wherein n is a unit normal vector of the contact surface; j. the design is a square₁、J₂Is a current density vector; v₁、V₂Voltage on both sides of the contact surface; h is_cTo shrink conductivity; sigma_asp、m_aspRespectively the average height and the slope of the surface roughness; p is the contact stress; h_cIs the surface micro-hardness of the object.

3. The all-fiber passive charged body temperature monitoring method of claim 1, wherein a least squares fit is used to establish the contact position to the temperature at the plurality of monitoring point positions.

4. The all-fiber passive charged body temperature monitoring method of claim 3, wherein the linear function model is:

y＝Ax+b (2)。

5. the all-fiber passive charged body temperature monitoring method of claim 4, wherein the least squares method is used to establish the fitting relationship between the contact position and the temperatures of the plurality of monitoring point positions as follows:

6. the all-fiber passive charged body temperature monitoring method of claim 5, wherein the sample error is:

e＝Y-Ax-b (4)。

7. the all-fiber passive charged body temperature monitoring method of claim 6, wherein a criterion for fitting a relationship is to minimize said sample error.

8. The utility model provides an all-fiber passive electrified body temperature monitoring device which characterized in that includes:

the determining module is used for determining the contact position of the all-fiber passive charged body and the positions of a plurality of monitoring points;

the contact resistance calculation module is used for determining a plurality of contact resistances and respectively determining parameters of each contact resistance;

the optical measurement module is used for connecting each contact resistor with the all-fiber passive charged body and measuring optical signals of the contact position and the positions of the monitoring points after the all-fiber passive charged body is electrified;

the processing module is used for converting optical signals of the contact position and the plurality of monitoring point positions into electric signals so as to determine the temperatures of the contact position and the plurality of monitoring point positions;

and the calculation module is used for establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions and calculating the temperature of the contact position according to the fitting relation.

9. The all-fiber passive charged body temperature monitoring device of claim 8, wherein said light measuring module comprises:

and the fiber grating sensor is used for measuring optical signals of the contact position and the positions of a plurality of monitoring points.

10. The all-fiber passive charged body temperature monitoring device of claim 9, wherein said processing module comprises:

the optical analysis unit comprises a laser light source consisting of a light source and an F-P filter and a corresponding photoelectric conversion module, and converts optical signals at the contact position and the plurality of monitoring point positions into electric signals;

and the temperature calculation unit determines the temperatures of the contact position and the positions of the monitoring points through the electric signals.

Technical Field

The invention relates to the technical field of temperature on-line monitoring of high-voltage switch equipment, in particular to a method and a device for monitoring the temperature of an all-fiber passive charged body.

Background

With the rapid development of science and technology in recent years, the demand of people for electric power is more and more great, and the electric power load is increased rapidly. In the operation process of a power plant, the contact parts of some electrical equipment have the phenomena of surface oxidation, contact looseness and the like, which can cause poor contact of the contacts and increase contact resistance, further cause current-carrying faults, and cause damages such as power failure and the like due to overhigh temperature and even burning of the contacts; some equipment causes temperature rise due to the structure of the equipment and friction rotation in the working process, and the ageing of the equipment can be caused by overhigh temperature, fire can be caused in serious conditions, the life and property safety of people can be endangered, and great loss is caused. And such accidents occur every year. Therefore, the temperature of important electrical equipment is monitored in real time on line so as to take corresponding measures and ensure the safe operation of the power plant.

The high-voltage switch cabinet is important switch equipment of a transformer substation and plays a key control role in the power generation, power transmission and distribution and power conversion processes. The inside heat dispersion of closed high tension switchgear is poor, causes the unusual temperature rise of interior power equipment of cabinet easily, can cause the conflagration when serious. The high-voltage switch cabinet has the advantages of rich types of internal electrical elements and complex space structure, and the main electrical elements comprise a shell, a partition plate, a bus, a sleeve, a current transformer, a cable, a moving contact and a static contact of a circuit breaker, a grounding switch and other secondary equipment. The problem of heat generation of high-voltage switch cabinets can be considered from two aspects, namely heat generation and heat transfer. In the exothermic analysis, the heat source is mainly joule loss of current carrying conductors and electric contacts, eddy current and hysteresis loss in magnetic conductors, dielectric loss in electric insulating materials, heat energy generated in equipment outside a cabinet and in the natural environment. In terms of heat transfer, the high-voltage switch cabinet practical situation is mainly divided into three types of transfer, namely heat conduction, heat convection and heat radiation.

The electrical equipment to be monitored mainly comprises: (1) breaker contacts, knife switch contacts. A circuit breaker is a switching device capable of closing, carrying, and opening a current under a normal circuit condition and closing, carrying, and opening a current under an abnormal circuit condition within a predetermined time. The main function of the knife switch is to isolate the power supply. The contact part of the current contact in the breaker and the disconnecting link can cause overlarge contact resistance due to aging or unreliable contact, so that the contact generates heat, the mechanical strength of a metal material is reduced due to overheating, an insulating material is aged, the insulating material can be broken down under high pressure, and even the contact can explode due to high-temperature melting in severe cases. (2) An iron core and a winding of the transformer; stator and rotor cores and windings of the generator. The temperature rise of the transformer affects the load capacity, the service life and the loss of a power system, and if the heat dissipation is poor, the normal operation of equipment can be endangered, and even faults can be caused. (3) A closed bus bar system. Bus bar joint temperature rise is one of the main bus bar failures. (4) And (4) a cable interlayer. The cable interlayer refers to a structure layer for laying cables of instruments, control devices, disks, tables and cabinets in a control room and/or an electronic equipment room. The cable interlayer is one of the most dense places of cables of power plants and power substations. Most of insulating materials and fillers covered on the surface of the cable are inflammable and easy to burn, particularly, when the cable is short-circuited or meets a high-temperature condition, the ignition point of the insulating materials on the surface of the cable is lower, and most of the insulating materials and fillers covered on the surface of the cable are polyvinyl chloride materials and are easy to burn when meeting high temperature. (5) And a frequency converter. The frequency converter provides the required power supply voltage according to the actual requirement of the motor, so as to achieve the purposes of energy saving and speed regulation. The temperature monitoring on the frequency converter displays the temperature of the transformer, the temperature of the module can be seen on the control screen, and when the module is over-temperature, an alarm picture can be displayed. (6) And a power distribution room. The power distribution room is provided with a plurality of devices, such as a circuit breaker, a disconnecting switch, a current transformer, a voltage transformer and other electrical devices. And the cubical switchboard that most equipment place is relative confined space, and the heat can constantly gather in inside, if can't in time discharge the heat, can lead to the interior electrical equipment high temperature of cabinet. Excessive temperatures can accelerate degradation of the component insulation and may even cause a fire. (7) And (4) a storage battery. The storage battery is a standby power supply of a direct current system of the transformer substation, and the temperature of the storage battery chamber is preferably kept at about 25 ℃.

Few solutions exist for online monitoring of the temperature of electrical equipment, including: the ZigBee wireless module is used for monitoring based on a temperature sensor, however, the conventional temperature sensors are a thermistor sensor and a thermocouple sensor, the linearity of the thermistor sensor is extremely poor, standardization and a thermistor curve are difficult to provide, and the small size of the thermistor sensor also makes the thermistor sensor sensitive to natural errors, so that the thermistor sensor can be permanently damaged if exposed to high heat. The thermocouple sensor has low sensitivity, and is easily influenced by interference signals and temperature drift of the preamplifier. The development of the internet of things is accelerated by the appearance of the ZigBee technology, but the ZigBee wireless module has great defects: (1) the network address allocated to a node in ZigBee PNAs can change, even rename under certain conditions, and therefore it cannot be guaranteed to send data to the correct device, especially in strong electromagnetic interference environments. (2) The fixed working channel, the 2.4G HZ frequency used by the ZigBee network, and many other devices (such as cellular phones, microwaves, etc.) are also used, and when the initial energy scan of ZigBee is completed, if the initial channel selected by ZigBee is bad, a new network cannot be reset. (3) The capacity is limited, and the flash memory used by the ZigBee is small, so that the function requirements of some advanced applications are difficult to meet. Therefore, the system has great instability when monitoring the temperature of the power equipment, a plurality of sensors are required to be placed, the networking difficulty is increased when the number of monitoring points is large, the use is very inconvenient, and the measurement error is increased in the electromagnetic interference environment.

Therefore, it is necessary to develop a method and a device for monitoring the temperature of an all-fiber passive charged body.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention provides an all-fiber passive charged body temperature monitoring method and device, which can monitor charged body temperature data in real time, effectively avoid the defects of low efficiency, missing detection, information isolated island and the like caused by manual inspection, and realize the integration of charged body temperature monitoring and information construction.

In a first aspect, an embodiment of the present disclosure provides an all-fiber passive charged body temperature monitoring method, including:

determining the contact position and a plurality of monitoring point positions of an all-fiber passive charged body;

determining a plurality of contact resistances, and respectively determining parameters of each contact resistance;

connecting each contact resistor with the all-fiber passive electrified body, and measuring optical signals of the contact position and the positions of a plurality of monitoring points after electrifying;

converting optical signals of the contact position and the plurality of monitoring point positions into electric signals, and further determining the temperature of the contact position and the plurality of monitoring point positions;

and establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions, and calculating the temperature of the contact position according to the fitting relation.

Preferably, the parameters of the contact resistance are:

wherein n is a unit normal vector of the contact surface; j. the design is a square₁、J₂Is a current density vector; v₁、V₂Voltage on both sides of the contact surface; h is_cTo shrink conductivity; sigma_asp、m_aspRespectively the average height and the slope of the surface roughness; p is the contact stress; h_cIs the surface micro-hardness of the object.

Preferably, a least squares fit is established of the stylus position to the temperature at the plurality of monitor point positions.

Preferably, the linear function model is:

y＝Ax+b (2)。

preferably, the least square method is used for establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions as follows:

preferably, the sample error is:

e＝Y-Ax-b (4)。

preferably, the criterion for fitting the relationship is to minimize the sample error.

As a specific implementation manner of the embodiment of the present disclosure, the embodiment of the present disclosure further provides an all-fiber passive charged body temperature monitoring device, including:

the determining module is used for determining the contact position of the all-fiber passive charged body and the positions of a plurality of monitoring points;

the contact resistance calculation module is used for determining a plurality of contact resistances and respectively determining parameters of each contact resistance;

the optical measurement module is used for connecting each contact resistor with the all-fiber passive charged body and measuring optical signals of the contact position and the positions of the monitoring points after the all-fiber passive charged body is electrified;

the processing module is used for converting optical signals of the contact position and the plurality of monitoring point positions into electric signals so as to determine the temperatures of the contact position and the plurality of monitoring point positions;

and the calculation module is used for establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions and calculating the temperature of the contact position according to the fitting relation.

Preferably, the light measuring module includes:

and the fiber grating sensor is used for measuring optical signals of the contact position and the positions of a plurality of monitoring points.

Preferably, the processing module comprises:

the optical analysis unit comprises a laser light source consisting of a light source and an F-P filter and a corresponding photoelectric conversion module, and converts optical signals at the contact position and the plurality of monitoring point positions into electric signals;

and the temperature calculation unit determines the temperatures of the contact position and the positions of the monitoring points through the electric signals.

Preferably, the parameters of the contact resistance are:

wherein n is a unit normal vector of the contact surface; j. the design is a square₁、J₂Is a current density vector; v₁、V₂Voltage on both sides of the contact surface; h is_cTo shrink conductivity; sigma_asp、m_aspRespectively the average height and the slope of the surface roughness; p is the contact stress; h_cIs the surface micro-hardness of the object.

Preferably, a least squares fit is established of the stylus position to the temperature at the plurality of monitor point positions.

Preferably, the linear function model is:

y＝Ax+b (2)。

preferably, the least square method is used for establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions as follows:

preferably, the sample error is:

e＝Y-Ax-b (4)。

preferably, the criterion for fitting the relationship is to minimize the sample error.

The beneficial effects are that:

1. the all-fiber passive electrified body temperature on-line monitoring adopts light as a sensing signal, has the advantages of intrinsic safety, no electromagnetic interference, high precision and the like, and can meet the temperature monitoring requirement of an electrified body, especially a high-voltage electrified body.

2. The electrified body temperature data of full optical fiber passive electrified body temperature on-line monitoring can be monitored in real time, the defects of low efficiency, missing detection, information isolated island and the like caused by manual inspection can be effectively avoided, and the integration of electrified body temperature monitoring and informatization construction are realized.

The method and apparatus of the present invention have other features and advantages which will be apparent from or are set forth in detail in the accompanying drawings and the following detailed description, which are incorporated herein, and which together serve to explain certain principles of the invention.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts.

Fig. 1 is a schematic diagram illustrating the contact position and the monitoring point position of an all-fiber passive charged body according to an embodiment of the present invention.

Fig. 2a and 2b show temperature distribution diagrams when a rated current 1250A passes and an adjacent dangerous current 2500A passes, respectively, regardless of contact resistance, according to an embodiment of the present invention.

Fig. 3a and 3b show temperature distribution diagrams when a rated current 1250A passes and an adjacent dangerous current 2500A passes, respectively, considering normal contact resistance according to an embodiment of the present invention.

Fig. 4 is a diagram illustrating a variation trend of each position when the rated current 1250A passes according to an embodiment of the present invention.

Fig. 5 shows a schematic diagram of the trends of various positions when the near-dangerous current 2500A passes according to one embodiment of the present invention.

FIG. 6 shows a schematic diagram of the fit of monitoring point 1 to the contact position when rated current 1250A is passed, according to one embodiment of the invention.

FIG. 7 shows a schematic diagram of the fit of monitor Point 2 to contact position when a rated current 1250A is passed, according to one embodiment of the present invention.

FIG. 8 shows a schematic diagram of the fit of monitoring point 1 to the contact position when near hazardous current 2500A is passed through, according to one embodiment of the invention.

FIG. 9 shows a schematic diagram of the fit of monitor point 2 to the contact position when near hazardous current 2500A is passed through, according to one embodiment of the invention.

Fig. 10 shows a flow chart of the steps of an all-fiber passive charged body temperature monitoring method according to one embodiment of the present invention.

Fig. 11 shows a block diagram of an all-fiber passive charged body temperature monitoring device according to an embodiment of the present invention.

Description of reference numerals:

201. a determination module; 202. a contact resistance calculation module; 203. a light measuring module; 204. a processing module; 205. and a calculation module.

Detailed Description

Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.

The invention provides a method for monitoring the temperature of an all-fiber passive charged body, which comprises the following steps:

determining the contact position and a plurality of monitoring point positions of an all-fiber passive charged body;

determining a plurality of contact resistances, and respectively determining parameters of each contact resistance;

connecting each contact resistor with an all-fiber passive charged body, and measuring optical signals of the contact position and the positions of a plurality of monitoring points after electrification;

converting optical signals of the contact position and the plurality of monitoring point positions into electric signals, and further determining the temperature of the contact position and the plurality of monitoring point positions;

and establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions, and calculating the temperature of the contact position through the fitting relation.

In one example, the parameters of the contact resistance are:

wherein n is a unit normal vector of the contact surface; j. the design is a square₁、J₂Is a current density vector; v₁、V₂Voltage on both sides of the contact surface; h is_cTo shrink conductivity; sigma_asp、m_aspAre respectively provided withThe average height and slope of the surface roughness; p is the contact stress; h_cIs the surface micro-hardness of the object.

In one example, a least squares fit is established of the stylus position to the temperature at the plurality of monitor point locations.

In one example, the linear function model is:

y＝Ax+b (2)。

in one example, a least squares method is used to establish a fit relationship between the stylus position and the temperature at a plurality of monitor point positions as follows:

in one example, the sample error is:

e＝Y-Ax-b (4)。

in one example, the criterion for fitting the relationship is to minimize sample errors.

Fig. 1 is a schematic diagram illustrating the contact position and the monitoring point position of an all-fiber passive charged body according to an embodiment of the present invention.

In particular, the structure of the breaker contact in the switch cabinet is special, and a fiber bragg grating temperature sensor cannot be directly installed at the contact position, so that the temperature of the fiber bragg grating temperature sensor cannot be directly measured, and the temperature of the contact cannot be indirectly fed back through other positions. Numerical simulation research is carried out on the temperature field of the high-voltage switch cabinet, and the mathematical model that the temperature of the monitoring point and the temperature of the contact have correspondence when different currents flow through the model is obtained, wherein the model and the position of the monitoring point are shown in figure 1.

Joule heat is generated when current flows through a conductor, and the calculation formula of the joule heat is as follows:

wherein Q is a heat source; r is contact resistance; i is the current flowing through the conductor; t is time. The contact resistance is divided into a conductor resistance and an extra resistance, wherein the extra resistance is formed under the external action and comprises a contraction resistance and a film resistance:

R_j＝R_s+R_b (6)

wherein R is_sIs a shrinkage resistance; r_bIs a film resistance; when current flows through a conductor, the resistance formed by the contraction of the current line is called the contraction resistance. The contacted conductor can adsorb impurities, dust and other pollutants in the operation process, so that the surface of the conductor is oxidized to form a surface film layer, namely a film layer resistor. The influence factors of the contact resistance mainly include contact body materials, positive pressure, surface state and the like, are relatively difficult to calculate, and are usually calculated by an empirical formula:

wherein F is the contact pressure; m is a coefficient related to the contact form; kc is a coefficient relating to a contact material, a contact manner, and the like, and is generally found by an experiment. The COMSOL Multiphysics software integrates the theory of multiple physical fields into the electric contact analysis, and the parameters of the contact resistance are deduced to be formula (1) through corresponding variable replacement and simplification.

The heat transfer includes three modes of heat conduction, heat convection and heat radiation. Thermal conduction is within a single body or between multiple contacting bodies having temperature differences, and in order to balance such temperature differences, energy is transferred between adjacent particles, such as lattice vibrations, gas molecule collisions, electron transfer, and the like. It follows the fourier law:

wherein, P_cdIs the heat conduction power; the negative sign indicates the conduction direction; k is the thermal conductivity of the object; t is the object temperature.

Heat convection heat transfer occurs inside the fluid, with the movement to balance the temperature difference. Convection is divided into natural convection and forced convection, the natural convection occurs inside an object, and density change caused by temperature difference of the object itself causes heat energy transfer. Forced convection is the transfer of thermal energy resulting from the movement of a fluid under the influence of an external force. The switch cabinet is closed and cannot be influenced by the outside, so the switch cabinet is natural convection. The expression is as follows:

wherein, P_dlHeat dissipation power for convection; ρ is the fluid density; c_pIs the specific heat capacity of the fluid; u is the fluid flow rate;is a hamiltonian.

The heat radiation is different from the two transmission modes, is not influenced by external conditions, and is generated by emitting electromagnetic waves due to the temperature of an object. As long as the temperature of the object is above zero, thermal radiation occurs while absorbing energy emitted by other objects. The influence of the thermal radiation on the switchgear is not so great that its influence on the temperature will be neglected in the simulation process.

In the long-term operation process, the contact position in the high-voltage switch cabinet is easy to generate overheating due to the increase of contact resistance, and related accidents are caused. However, due to factors such as the structure of the cabinet body and the position of the contact, the temperature at the position of the contact is difficult to be accurately monitored on line in real time, and the current engineering is mainly used for monitoring the temperature at a bus measuring point close to the contact in real time so as to feed back the temperature at the position of the contact. Therefore, the numerical simulation research is carried out on the temperature field of the model through the Joule thermal module of COMSOL Multiphysics multi-physical field coupling software. Under the condition of not considering contact resistance of a contact, the temperature rise conditions of rated current and near dangerous current of a switch cabinet breaker are respectively analyzed; in addition, when contact resistance exists, numerical simulation analysis is carried out to the temperature rise condition of traditional temperature monitoring point and contact position in the cubical switchboard. The result shows that the temperature of the circuit breaker loop is increased along with the increase of the contact resistance, and the temperature of the monitoring point and the temperature of the contact are required to be corrected by corresponding temperature difference. And (3) performing data fitting on the simulation numerical value by a least square method, establishing a mathematical model of the temperature of the monitoring point and the temperature of the contact, and ensuring the fitting precision to be more than 95%.

Fig. 2a and 2b show temperature distribution diagrams when a rated current 1250A passes and an adjacent dangerous current 2500A passes, respectively, regardless of contact resistance, according to an embodiment of the present invention.

Fig. 3a and 3b show temperature distribution diagrams when a rated current 1250A passes and an adjacent dangerous current 2500A passes, respectively, considering normal contact resistance according to an embodiment of the present invention.

The temperature distribution when the rated current 1250A is passed and when the near dangerous current 2500A is passed regardless of the contact resistance is shown in fig. 2a and 2 b.

The temperature distributions when the rated current 1250A is passed and when the near dangerous current 2500A is passed in consideration of the normal contact resistance are shown in fig. 3a and 3 b.

The values of the contact resistance change are shown in table 1.

TABLE 1

Fig. 4 is a diagram illustrating a variation trend of each position when the rated current 1250A passes according to an embodiment of the present invention.

Fig. 5 shows a schematic diagram of the trends of various positions when the near-dangerous current 2500A passes according to one embodiment of the present invention.

FIG. 6 shows a schematic diagram of the fit of monitoring point 1 to the contact position when rated current 1250A is passed, according to one embodiment of the invention.

And measuring the data of the positions of the monitoring points 1 and 2 and the position of the contact according to different contact resistances. And performing linear fitting on the data by adopting a least square method. When the rated current 1250A passes, the fitting relation of the monitoring point 1 and the contact position is shown in fig. 6, and the expression is as follows, wherein alpha represents the correction coefficient of an analog value and an actual value:

y＝(1.207x-8.369)·α (10)

FIG. 7 shows a schematic diagram of the fit of monitor Point 2 to contact position when a rated current 1250A is passed, according to one embodiment of the present invention.

The fitting relationship between the monitoring point 2 and the position of the contact is shown in fig. 7, and the expression is as follows, wherein λ represents a correction coefficient of an analog value and an actual value:

y＝(1.217x-6.892)·λ (11)

FIG. 8 shows a schematic diagram of the fit of monitoring point 1 to the contact position when near hazardous current 2500A is passed through, according to one embodiment of the invention.

When the near-danger current 25000A passes, the fitting relation of the monitoring point 1 and the contact position is shown in FIG. 8, and the expression is as follows, wherein beta represents the correction coefficient of an analog value and an actual value:

y＝(1.401x-35.05)·β (12)

FIG. 9 shows a schematic diagram of the fit of monitor point 2 to the contact position when near hazardous current 2500A is passed through, according to one embodiment of the invention.

The fitting relationship between the monitoring point 2 and the position of the contact is shown in fig. 9, and the expression is as follows, wherein eta represents the correction coefficient of the analog value and the actual value:

y＝(1.407x-25.856)·η (13)

the straight line fit is matched using the least squares method, i.e., the best function to find the data by minimizing the sum of the squares of the errors. For the one-dimensional linear regression model, it was assumed that n sets of observations (X1, Y1), (X2, Y2), …, (Xn, Yn) were obtained from the population. For these n points in the plane, an infinite number of curves can be used for fitting. The sample regression function is required to fit the set of values as well as possible. Taken together, this straight line appears most reasonable at the center of the sample data. The criteria for selecting the best fit curve may be determined as: the total fitting error (i.e., total residual) is minimized. And the principle of least squares is to determine the line position with "sum of squared residuals" minimum. The linear fit is therefore a least squares fit.

The fitting relation between the contact position and the temperatures of the monitoring point positions is established by adopting a least square method, the linear function model is a formula (2), the fitting relation between the contact position and the temperatures of the monitoring point positions is established by adopting the least square method and is a formula (3), and the sample error is a formula (4). The criterion for the fit relationship is to minimize sample error.

The code implementation process is as follows:

the invention also provides an all-fiber passive charged body temperature monitoring device, which comprises:

the determining module is used for determining the contact position of the all-fiber passive charged body and the positions of a plurality of monitoring points;

the contact resistance calculation module is used for determining a plurality of contact resistances and respectively determining parameters of each contact resistance;

the optical measurement module is used for connecting each contact resistor with the all-fiber passive charged body and measuring optical signals of the contact position and the positions of the monitoring points after electrification;

the processing module is used for converting optical signals of the contact position and the plurality of monitoring point positions into electric signals so as to determine the temperatures of the contact position and the plurality of monitoring point positions;

and the calculation module is used for establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions and calculating the temperature of the contact position through the fitting relation.

In one example, the light measurement module includes:

and the fiber grating sensor is used for measuring optical signals of the contact position and the positions of a plurality of monitoring points.

In one example, the processing module includes:

the optical analysis unit comprises a laser light source consisting of a light source and an F-P filter and a corresponding photoelectric conversion module, and converts optical signals at the contact position and the plurality of monitoring point positions into electric signals;

and the temperature calculation unit determines the temperatures of the contact position and the positions of the monitoring points through the electric signals.

In one example, the parameters of the contact resistance are:

wherein n is a unit normal vector of the contact surface; j. the design is a square₁、J₂Is a current density vector; v₁、V₂Voltage on both sides of the contact surface; h is_cTo shrink conductivity; s_asp、m_aspRespectively the average height and the slope of the surface roughness; p is the contact stress; h_cIs the surface micro-hardness of the object.

In one example, a least squares fit is established of the stylus position to the temperature at the plurality of monitor point locations.

In one example, the linear function model is:

y＝Ax+b (2)。

in one example, a least squares method is used to establish a fit relationship between the stylus position and the temperature at a plurality of monitor point positions as follows:

in one example, the sample error is:

e＝Y-Ax-b (4)。

in one example, the criterion for fitting the relationship is to minimize sample errors.

Specifically, the optical measurement module comprises a fiber grating sensor, each contact resistor is connected with a full-fiber passive charged body, and the positions of the contact and the monitoring points are measured after the contact is electrifiedAn optical signal; the main material of the fiber grating is SiO₂And the anti-electromagnetic interference performance is high. The non-metallization packaging process is utilized, and the packaging structure has the characteristics of heat conduction and high strength.

The processing module comprises: the optical analysis unit comprises a laser light source consisting of a light source and an F-P filter and a corresponding photoelectric conversion module, wherein optical signals at the position of a contact and the positions of a plurality of monitoring points are converted into electric signals; the temperature calculation unit comprises a data acquisition and analysis assembly, and the temperature of the contact position and the positions of the monitoring points is determined through electric signals.

The all-fiber passive charged body temperature monitoring device further comprises a software platform, and the software platform comprises any equipment capable of displaying data, such as a computer, a mobile phone and the like, and is used for displaying the running state of each equipment in the power plant in real time, wherein a mathematical prediction model is added, and the temperature value of a contact in the high-voltage switch cabinet can be displayed in real time.

The structure of the breaker contact in the switch cabinet is special, and the fiber bragg grating temperature sensor cannot be directly installed at the contact position, so that the temperature of the fiber bragg grating temperature sensor cannot be directly measured, and the temperature of the contact can be indirectly fed back through other positions. Numerical simulation research is carried out on the temperature field of the high-voltage switch cabinet, and the mathematical model that the temperature of the monitoring point and the temperature of the contact have correspondence when different currents flow through the model is obtained, wherein the model and the position of the monitoring point are shown in figure 1.

Joule heat is generated when the current flows through the conductor, and the calculation formula of the joule heat is formula (5). The contact resistance is divided into a conductor resistance and an extra resistance, wherein the extra resistance is formed under the external action and comprises a contraction resistance and a film resistance, namely, the formula (6). The contacted conductor can adsorb impurities, dust and other pollutants in the operation process, so that the surface of the conductor is oxidized to form a surface film layer, namely a film layer resistor. The influence factors of the contact resistance are mainly contact material, positive pressure, surface state, and the like, and are relatively difficult to calculate, and are generally calculated by empirical formula (7). The COMSOL Multiphysics software integrates the theory of multiple physical fields into the electric contact analysis, and the parameters of the contact resistance are deduced to be formula (1) through corresponding variable replacement and simplification.

The heat transfer includes three modes of heat conduction, heat convection and heat radiation. Thermal conduction is within a single body or between multiple contacting bodies having temperature differences, and in order to balance such temperature differences, energy is transferred between adjacent particles, such as lattice vibrations, gas molecule collisions, electron transfer, and the like. It follows the fourier law as equation (8).

Heat convection heat transfer occurs inside the fluid, with the movement to balance the temperature difference. Convection is divided into natural convection and forced convection, the natural convection occurs inside an object, and density change caused by temperature difference of the object itself causes heat energy transfer. Forced convection is the transfer of thermal energy resulting from the movement of a fluid under the influence of an external force. The switch cabinet is closed and cannot be influenced by the outside, so the switch cabinet is natural convection. The expression is formula (9).

The heat radiation is different from the two transmission modes, is not influenced by external conditions, and is generated by emitting electromagnetic waves due to the temperature of an object. As long as the temperature of the object is above zero, thermal radiation occurs while absorbing energy emitted by other objects. The influence of the thermal radiation on the switchgear is not so great that its influence on the temperature will be neglected in the simulation process.

In the long-term operation process, the contact position in the high-voltage switch cabinet is easy to generate overheating due to the increase of contact resistance, and related accidents are caused. However, due to factors such as the structure of the cabinet body and the position of the contact, the temperature at the position of the contact is difficult to be accurately monitored on line in real time, and the current engineering is mainly used for monitoring the temperature at a bus measuring point close to the contact in real time so as to feed back the temperature at the position of the contact. Therefore, the numerical simulation research is carried out on the temperature field of the model through the Joule thermal module of COMSOL Multiphysics multi-physical field coupling software. Under the condition of not considering contact resistance of a contact, the temperature rise conditions of rated current and near dangerous current of a switch cabinet breaker are respectively analyzed; in addition, when contact resistance exists, numerical simulation analysis is carried out to the temperature rise condition of traditional temperature monitoring point and contact position in the cubical switchboard. The result shows that the temperature of the circuit breaker loop is increased along with the increase of the contact resistance, and the temperature of the monitoring point and the temperature of the contact are required to be corrected by corresponding temperature difference. And (3) performing data fitting on the simulation numerical value by a least square method, establishing a mathematical model of the temperature of the monitoring point and the temperature of the contact, and ensuring the fitting precision to be more than 95%.

The temperature distribution when the rated current 1250A is passed and when the near dangerous current 2500A is passed regardless of the contact resistance is shown in fig. 2a and 2 b.

The temperature distributions when the rated current 1250A is passed and when the near dangerous current 2500A is passed in consideration of the normal contact resistance are shown in fig. 3a and 3 b.

The values of the contact resistance change are shown in table 1.

And measuring the data of the positions of the monitoring points 1 and 2 and the position of the contact according to different contact resistances. And performing linear fitting on the data by adopting a least square method. When the rated current 1250A passes through, the fitting relation between the monitoring point 1 and the contact position is shown in fig. 6, the expression is formula (10), the fitting relation between the monitoring point 2 and the contact position is shown in fig. 7, and the expression is formula (11).

When the near dangerous current 25000A passes, the fitting relation of the monitoring point 1 and the contact position is shown in FIG. 8, the expression is formula (12), the fitting relation of the monitoring point 2 and the contact position is shown in FIG. 9, and the expression is formula (13).

The straight line fit is matched using the least squares method, i.e., the best function to find the data by minimizing the sum of the squares of the errors. For the one-dimensional linear regression model, it was assumed that n sets of observations (X1, Y1), (X2, Y2), …, (Xn, Yn) were obtained from the population. For these n points in the plane, an infinite number of curves can be used for fitting. The sample regression function is required to fit the set of values as well as possible. Taken together, this straight line appears most reasonable at the center of the sample data. The criteria for selecting the best fit curve may be determined as: the total fitting error (i.e., total residual) is minimized. And the principle of least squares is to determine the line position with "sum of squared residuals" minimum. The linear fit is therefore a least squares fit.

The fitting relation between the contact position and the temperatures of the monitoring point positions is established by adopting a least square method, the linear function model is a formula (2), the fitting relation between the contact position and the temperatures of the monitoring point positions is established by adopting the least square method and is a formula (3), and the sample error is a formula (4). The criterion for the fit relationship is to minimize sample error.

To facilitate understanding of the aspects of the embodiments of the present invention and their effects, two specific application examples are given below. It will be understood by those skilled in the art that this example is merely for the purpose of facilitating an understanding of the present invention and that any specific details thereof are not intended to limit the invention in any way.

Example 1

Fig. 10 shows a flow chart of the steps of an all-fiber passive charged body temperature monitoring method according to one embodiment of the present invention.

As shown in fig. 10, the all-fiber passive charged body temperature monitoring method includes: step 101, determining the contact position and a plurality of monitoring point positions of an all-fiber passive electrified body; step 102, determining a plurality of contact resistances, and respectively determining parameters of each contact resistance; 103, connecting each contact resistor with a full-optical-fiber passive charged body, and measuring optical signals of the contact position and the positions of a plurality of monitoring points after electrification; 104, converting optical signals of the contact position and the plurality of monitoring point positions into electric signals, and further determining the temperature of the contact position and the plurality of monitoring point positions; and 105, establishing a fitting relation between the contact position and the temperatures of the plurality of monitoring point positions, and calculating the temperature of the contact position through the fitting relation.

The contact of the breaker of a certain power plant is measured, and the voltage of the power plant is 10 KV. The volume of the sample is 1.57cm³The fiber grating sensor is arranged near a contact of the circuit breaker, the optical analysis module comprises a laser light source consisting of a light source and an F-P filter and a corresponding photoelectric conversion module, a photoelectric conversion light signal is collected by the data acquisition module, the signal is finally analyzed by the analog-to-digital conversion module, and finally, the signal is displayedOn a software device. In this case, the average temperature of the circuit breaker contact is measured as 60 ℃ for the one week, 63 ℃ for the one week, 63.781 α ℃ for the average temperature of the contact is calculated according to the formula, and the measurement error is 1.24%, and since the relevant conditions set at the time of simulation cause an error from the time of actual measurement, a correction coefficient α is added thereto. The weekly average temperature of monitoring point 2 was monitored to be 58 ℃. The average temperature of the contact was calculated to be 63.692 α deg.C according to the formula, with a measurement error of 1.1%. The maximum temperature reached 67 ℃ and the minimum temperature 29 ℃.

The contact of the breaker of a certain power plant is measured, and the voltage of the power plant is 220 KV. The volume of the sample is 1.57cm³The fiber bragg grating sensor is placed near a contact of the circuit breaker, the optical analysis module comprises a laser light source and a corresponding photoelectric conversion module, the laser light source consists of a light source and an F-P filter, a photoelectric conversion light signal is collected by the data collection module, the signal is finally analyzed by the analog-to-digital conversion module, and finally the signal is displayed on software equipment. In this case, the average temperature of the breaker contacts for one week was monitored to be 70 ℃, the maximum temperature to 80 ℃ and the minimum temperature to 39 ℃.

Measurements were made on the transformer windings of a power plant. The volume of the sample is 1.57cm³The fiber bragg grating sensor is arranged near the transformer, the optical analysis module comprises a laser light source and a corresponding photoelectric conversion module, the laser light source consists of a light source and an F-P filter, a photoelectric conversion light signal is collected by the data collection module, and the signal is finally analyzed by the analog-to-digital conversion module and finally displayed on software equipment. In this case, the average temperature of the transformer for one week was monitored to be 55 ℃, the maximum temperature to 67 ℃ and the minimum temperature to be 25 ℃.

The bus connector of a certain power plant is measured, and the voltage of the power plant is 220 KV. A fiber grating sensor with the volume of 1.57cm3 is placed at a bus joint, an optical analysis module comprises a laser light source consisting of a light source and an F-P filter and a corresponding photoelectric conversion module, a photoelectric conversion light signal is collected by a data acquisition module, and the signal is finally analyzed by an analog-to-digital conversion module and finally displayed on software equipment. In this case, the average temperature of the busbar joint for one week was monitored to be 40 ℃, the maximum temperature to 50 ℃ and the minimum temperature to 23 ℃.

Example 2

Fig. 11 shows a block diagram of an all-fiber passive charged body temperature monitoring device according to an embodiment of the present invention.

As shown in fig. 11, the all-fiber passive charged body temperature monitoring device includes:

the determining module 201 is used for determining the contact position and the positions of a plurality of monitoring points of the all-fiber passive charged body;

the contact resistance calculation module 202 is used for determining a plurality of contact resistances and determining parameters of each contact resistance respectively;

the light measurement module 203 is used for connecting each contact resistor with the all-fiber passive charged body and measuring optical signals of the contact position and the positions of the monitoring points after electrification;

the processing module 204 is configured to convert the optical signals at the contact position and the plurality of monitoring point positions into electrical signals, and further determine the temperatures at the contact position and the plurality of monitoring point positions;

the calculation module 205 establishes a fitting relationship between the contact position and the temperatures of the plurality of monitoring point positions, and calculates the temperature of the contact position according to the fitting relationship.

As an alternative, the light measuring module comprises:

and the fiber grating sensor is used for measuring optical signals of the contact position and the positions of a plurality of monitoring points.

As an alternative, the processing module comprises:

the optical analysis unit comprises a laser light source consisting of a light source and an F-P filter and a corresponding photoelectric conversion module, and converts optical signals at the contact position and the plurality of monitoring point positions into electric signals;

and the temperature calculation unit determines the temperatures of the contact position and the positions of the monitoring points through the electric signals.

Alternatively, the parameters of the contact resistance are:

wherein n is a unit normal vector of the contact surface; j. the design is a square₁、J₂Is a current density vector; v₁、V₂Voltage on both sides of the contact surface; h is_cTo shrink conductivity; sigma_asp、m_aspRespectively the average height and the slope of the surface roughness; p is the contact stress; h_cIs the surface micro-hardness of the object.

Alternatively, a least squares method is used to establish a fit relationship between the stylus position and the temperature at multiple monitoring point positions.

Alternatively, the linear function model is:

y＝Ax+b (2)。

as an alternative, a least square method is used to establish a fitting relationship between the contact position and the temperatures of the plurality of monitoring point positions as follows:

as an alternative, the sample error is:

e＝Y-Ax-b (4)。

alternatively, the criterion for fitting the relationship is to minimize sample error.

It will be appreciated by persons skilled in the art that the above description of embodiments of the invention is intended only to illustrate the benefits of embodiments of the invention and is not intended to limit embodiments of the invention to any examples given.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.