CN115597704A

CN115597704A - Circuit breaker stroke monitoring device based on MEMS sensor and monitoring method thereof

Info

Publication number: CN115597704A
Application number: CN202211246841.1A
Authority: CN
Inventors: 罗加明; 左鑫; 刘枢; 刘伊健
Original assignee: State Grid Sichuan Electric Power Co Ltd
Current assignee: State Grid Sichuan Electric Power Co Ltd
Priority date: 2022-10-12
Filing date: 2022-10-12
Publication date: 2023-01-13

Abstract

The invention discloses a circuit breaker stroke monitoring device based on an MEMS sensor and a monitoring method thereof, relates to the technical field of on-line monitoring of circuit breakers, solves the problem of difficult sensor installation in the currently used circuit breaker contact stroke monitoring means, and has the technical scheme that: a circuit breaker stroke monitoring device based on MEMS sensor includes: the MEMS sensor and the fixing piece are fixed on the fixing band, the fixing band is wound on the circuit breaker insulation pull rod, and the fixing band is tightly sleeved on the insulation pull rod through the adjusting knob. Through the structure, the purposes of conveniently and quickly installing the MEMS sensor and improving the fixed reliability and the measured data reliability of the MEMS sensor are achieved, and meanwhile, the purposes of improving the effectiveness and the precision of the measured data and improving the measurement accuracy are achieved by arranging the singular point filtering algorithm and the Kalman filtering algorithm through historical data.

Description

Circuit breaker stroke monitoring device based on MEMS sensor and monitoring method thereof

Technical Field

The invention relates to the technical field of on-line monitoring of circuit breakers, in particular to a circuit breaker stroke monitoring device based on an MEMS sensor and a monitoring method thereof.

Background

Circuit breakers are the most prominent fast switching and fault isolation devices in electrical power systems. The health state of the circuit breaker plays a very important role in the safe and stable operation of the whole power grid.

The high-voltage circuit breaker is mostly provided with hydraulic, spring, pneumatic and other operating mechanisms, and the opening and closing tripping electromagnet of the mechanism is often subjected to bending deformation, rust or dirt adhesion in long-term operation to ensure that the electromagnet does not work smoothly, so that the circuit breaker fails to work; the short-circuit current, vibration and the like are cut off to cause mechanism deformation, the spring characteristic is changed, and the opening and closing time is too short or too long, different periods and the like.

On-line monitoring of mechanical characteristics of circuit breakers typically involves monitoring of coil current characteristics and stroke motion characteristics. The traditional on-line monitoring of the circuit breaker is mainly based on current monitoring of a switching-on coil and a switching-off coil, can accurately monitor the switching-off time of the circuit breaker and the working state of the switching-off coil, but cannot intuitively monitor important parameters such as the action speed and the compression stroke of a main contact. The current monitoring means of the contact stroke of the circuit breaker mainly comprises a laser ranging sensor (shown as a figure 3), a linear displacement sensor (shown as a figure 4) and an angular displacement sensor (shown as a figure 5), wherein the laser sensor is very precise, the service life of the sensor can be shortened by vibration and dust on the site, even the sensor fails, the installation requirement is high, and the field debugging is needed. The linear transmission sensor is difficult to fix, and holes need to be formed in the existing mechanism, so that the structural performance of the circuit breaker is affected. The angular displacement sensor needs to be provided with a hole on a breaker shaft to fix the angular displacement sensor, and the angular displacement sensor, the crank arm shaft and the additionally arranged measuring shaft need to be ensured to be concentric as much as possible.

Disclosure of Invention

The invention aims to provide a circuit breaker stroke monitoring device based on an MEMS sensor and a monitoring method thereof.

The technical purpose of the invention is realized by the following technical scheme:

a circuit breaker stroke monitoring device based on MEMS sensor includes: a MEMS sensor for monitoring circuit breaker travel data; the fixing piece comprises an adjusting knob and a fixing belt; the MEMS sensor is arranged on the fixing belt and used for forming a closed-loop structure around an insulating pull rod of the circuit breaker to be tested; the adjusting knob is arranged on the fixing belt and used for adjusting the size of the closed loop structure.

Furthermore, the fixed belt is sleeved with a first flexible pad for attaching the inner side of the fixed belt to an insulating pull rod of the circuit breaker.

Further, a mounting box is arranged on the fixing belt; the MEMS sensor is fixed in the mounting box.

Furthermore, a second flexible pad connected with the fixed box at the outer side is sleeved on the fixed belt.

A circuit breaker stroke monitoring method based on an MEMS sensor utilizes the circuit breaker stroke monitoring device based on the MEMS sensor to monitor the stroke of a circuit breaker, and comprises the following steps:

acquiring an initial acceleration value of an MEMS sensor on a breaker and acceleration values of the MEMS sensor at all moments acquired in a breaker switch contact action period;

cleaning the acceleration value in the action period to obtain the cleaned acceleration value and the cleaned moment corresponding to the cleaned acceleration value;

constructing an acceleration change curve of the MEMS sensor based on the initial acceleration value, the acceleration value after cleaning and the time after cleaning;

and obtaining a breaker stroke result based on the acceleration change curve of the MEMS sensor.

Further, the process of acquiring the initial acceleration value of the MEMS sensor on the circuit breaker specifically includes:

acquiring an acceleration value acquired by an MEMS sensor in a preset time before the on-off of a switch contact of a circuit breaker;

and carrying out mutation filtering processing on the acquired acceleration value to obtain the acceleration of the MEMS sensor.

Further, the action signal of the auxiliary switch, the coil current recording value and the acceleration sudden change value are calculated to obtain the preset time.

Further, the cleaning process specifically comprises the following steps:

constructing an action period-acceleration curve based on the acceleration values at all the moments collected in the action period;

comparing singular points in the action period-acceleration curve with reference data to obtain the change characteristics of the singular points in the action period-acceleration curve;

constructing a noise model based on the change characteristics of singular points in an action cycle-acceleration curve;

and cleaning the abnormal measured value in the action cycle-acceleration curve based on the noise model to obtain the cleaned acceleration value and the cleaned moment corresponding to the cleaned acceleration value.

Further, the singular point includes an abnormal value generated by an impact at the closing moment of the breaker switch contact and a vibration amount when the breaker switch contact operates.

Furthermore, based on the cleaned acceleration value and the comparison result between the cleaned moment corresponding to the cleaned acceleration value and the reference data, the Kalman filtering algorithm parameters are adjusted, and an acceleration change curve of the MEMS sensor is constructed.

Compared with the prior art, the invention has the following beneficial effects:

a circuit breaker stroke monitoring device based on MEMS sensor includes: the MEMS sensor and the fixing piece are fixed on the fixing band, the fixing band is wound on the circuit breaker insulation pull rod, and the fixing band is tightly sleeved on the insulation pull rod through the adjusting knob. Through the structure, the purposes of conveniently and quickly installing the MEMS sensor and improving the fixing reliability and the measured data reliability of the MEMS sensor are achieved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

fig. 1 is a schematic cross-sectional structural view of a circuit breaker stroke monitoring device based on an MEMS sensor according to this embodiment;

fig. 2 is a schematic structural diagram of a front view of the circuit breaker stroke monitoring device based on the MEMS sensor according to the embodiment;

FIG. 3 is a schematic diagram of a structure of a laser ranging sensor for monitoring the stroke of a contact of a circuit breaker in the prior art;

FIG. 4 is a schematic diagram of a structure for monitoring the stroke of a contact of a circuit breaker by a linear displacement sensor in the prior art;

fig. 5 is a schematic structural diagram of a contact stroke monitoring circuit breaker of an angular displacement sensor in the prior art.

Reference numbers and corresponding part names in the figures:

1-fixing the belt; 2-a first flexible mat; 3-a second flexible mat; 4-mounting a box; 5-a MEMS sensor; 6-adjusting knob.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Example (b):

the current monitoring method of the contact stroke of the breaker is a laser distance measuring sensor (as shown in figure 1), a linear displacement sensor (as shown in figure 2) and an angular displacement sensor (as shown in figure 3)

The laser ranging sensor adopts a laser triangular reflection type principle, the measuring precision can reach 10um, but the general range is short, the range is several centimeters to tens of centimeters, and the stroke monitoring of the stroke from a medium-voltage vacuum circuit breaker smaller than 1 centimeter to a high-voltage oil-less circuit breaker of tens of centimeters can be met. The semiconductor laser is focused on the object by the chip, and the reflected light is collected by the chip and projected onto the CCD array. The signal processor calculates the position of the light spots on the array by trigonometric function to obtain the distance to the object. The light emitter emits visible red light to the surface of an object through the head, the laser reflected by the object is transmitted to the receiver lens and received by the internal CCD linear camera, and the CCD linear camera can 'see' light spots under different angles according to different distances. According to the angle, the distance between the light and the camera can be known, and the digital signal processor can calculate the distance between the sensor and the measured object. Meanwhile, the position of the light beam on the receiving element is processed by an analog circuit and a digital circuit, and is analyzed by a microprocessor, so that a corresponding output value is usurped, and a standard data number is proportionally output in an analog quantity window set by a user.

This approach has the following problems: (1) Because the action time of the circuit breaker is short, generally within 100ms, and the action time of the quick circuit breaker is within 20ms, a high-refresh-rate laser sensor is needed, the cost is very high, generally tens of thousands yuan, and the cost is too high, so that the quick circuit breaker cannot be popularized and applied. (2) Laser sensors are very delicate and vibrations and dust in the field can reduce the life of the sensor and even render the sensor useless. (3) The laser sensor has high installation requirements and needs field debugging.

The displacement sensor is used for measuring the mechanical characteristics of the high-voltage circuit breaker, the opening and closing state of the circuit breaker can be judged by measuring the distance between the movable measuring head and the static measuring head, and the speed and the displacement of the movable measuring head are calculated. The linear displacement sensor or the pull rod type LVDT displacement sensor has good dynamic response characteristics and is more suitable for high-speed displacement measurement of the high-voltage circuit breaker. The potentiometer principle linear displacement sensor is low in cost and is widely applied to a high-voltage circuit breaker tester. The operation should standardize in the sensor installation use, and the measuring staff is together fixed reliably with the circuit breaker movable head, can not have relative rocking between the movable head and the sensor measuring staff when moving, otherwise can cause the measured data error to increase. This approach has the following problems: (1) The space of the field circuit breaker mechanism is narrow, and most of the field circuit breaker mechanism has insufficient space for installing the linear displacement sensor. (2) The linear transmission sensor is difficult to fix, and holes need to be formed in the existing mechanism, so that the structural performance of the circuit breaker is affected. (3) The various circuit breakers are different in model and shaft size, and the installation and fixing accessories need to be customized.

The linear displacement sensor can directly test the position change of a connecting shaft of the breaker and the contact through the linear displacement sensor, and can also indirectly measure the position change of the contact of the breaker through the rotating angle of a transmission shaft of the angular displacement sensor. The motion trail of the contact shaft of the circuit breaker has a certain corresponding relation with the rotating angle of the crank arm shaft, and all monitoring functions of the linear displacement sensor can be basically realized by measuring the rotating angle of the crank arm shaft. This approach has the following problems: (1) Although the installation space is smaller than that of the linear displacement sensor, the problem of limited installation space still exists. (2) The breaker shaft is required to be provided with a hole, the angular displacement sensor is required to be fixed, and the concentricity of the angular displacement sensor, the crank arm shaft and the additionally arranged measuring shaft is required to be ensured as much as possible. (3) The circuit breaker generally has a multi-stage crankshaft, the rotating angle of a crank arm shaft and the contact stroke are in a nonlinear corresponding relation, the corresponding coefficient is difficult to verify, and errors exist in calculation.

In order to solve the technical problems in the prior art, the embodiment provides a circuit breaker stroke monitoring device based on an MEMS sensor and a monitoring method thereof.

A circuit breaker stroke monitoring device based on a MEMS sensor 5 comprises: a MEMS sensor 5, the MEMS sensor 5 is used for monitoring circuit breaker travel data; the fixing piece comprises an adjusting knob 6 and a fixing belt 1; the fixing band 1 is provided with an MEMS sensor 5 which is used for forming a closed loop structure around an insulating pull rod of a circuit breaker to be detected; the adjusting knob 6 is arranged on the fixing band 1 and used for adjusting the size of the closed loop structure. The cover is equipped with the first flexible pad 2 that is used for inboard and circuit breaker insulating pull rod laminating on the fixed band 1. The fixing belt 1 is provided with an installation box 4; the MEMS sensor 5 is fixed in the mounting box 4. The fixing strap 1 is sleeved with a second flexible pad 3, the outer side of which is connected with the fixing box.

First flexible pad 2 and the flexible 3 middle parts of second are provided with the perforation, and fixed band 1 wears to establish in this perforation, and this fixed band 1 can select to be the stainless steel staple bolt ribbon. Adopt tight fit between first flexible pad 2, second flexible pad 3 and fixed band 1, after fixed band 1 is taut, first flexible pad 2 and second flexible pad 3 will produce the extrusion force to insulating pull rod after warping, let antiskid simultaneously produce great frictional force with the axle. The MEMS sensor 5 is small in size and light in weight, the probability of relative operation between the sensor and the insulating pull rod can be reduced, and the purpose of improving the reliability of the monitoring result of the MEMS sensor 5 is achieved. Meanwhile, the first flexible pad 2 and the second flexible pad 3 are attached to the insulating pull rod, so that the possibility that the action of the circuit breaker is blocked due to shifting loosening after the MEMS sensor 5 falls off can be reduced. The bottom of the second flexible pad 3 is connected with a mounting box 4 through a countersunk head screw, the MEMS sensor 5 is mounted in the mounting box 4, the MEMS sensor 5 adopts a sensor with a chip size, the overall size of the sensor box can be 25mm 8mm, and the convenience of mounting the MEMS sensor 5 in a circuit breaker with limited space is improved.

A circuit breaker stroke monitoring method based on an MEMS sensor utilizes the circuit breaker stroke monitoring device based on the MEMS sensor to monitor the circuit breaker stroke, and comprises the following steps: acquiring an initial acceleration value of an MEMS sensor on a breaker and acceleration values of the MEMS sensor at all moments acquired in a breaker switch contact action period; cleaning the acceleration value in the action period to obtain the cleaned acceleration value and the cleaned moment corresponding to the cleaned acceleration value;

constructing an acceleration change curve of the MEMS sensor based on the initial acceleration value, the acceleration value after cleaning and the time after cleaning; and obtaining a breaker stroke result based on the acceleration change curve of the MEMS sensor. The acquisition process of the acceleration initial value of the MEMS sensor on the circuit breaker specifically comprises the following steps: acquiring an acceleration value acquired by an MEMS sensor in a preset time before the on-off of a switch contact of a circuit breaker; and carrying out mutation filtering processing on the acquired acceleration value to obtain the acceleration of the MEMS sensor. And calculating the action signal of the auxiliary switch, the coil current recording value and the acceleration sudden change value to obtain the preset time. The cleaning treatment process specifically comprises the following steps: constructing an action period-acceleration curve based on the acceleration values collected in the action period at all times; comparing singular points in the action period-acceleration curve with reference data to obtain the change characteristics of the singular points in the action period-acceleration curve; constructing a noise model based on the change characteristics of singular points in an action cycle-acceleration curve; and cleaning the abnormal measured value in the action period-acceleration curve based on the noise model to obtain the cleaned acceleration value and the cleaned moment corresponding to the cleaned acceleration value. The singular point comprises an abnormal value generated by impact at the closing moment of the switch contact of the circuit breaker and vibration quantity generated when the switch contact of the circuit breaker acts. And adjusting Kalman filtering algorithm parameters based on the cleaned acceleration value and the comparison result of the cleaned moment corresponding to the cleaned acceleration value and the reference data, and constructing an acceleration change curve of the MEMS sensor.

Specifically, the method comprises the following steps: the data collected by the MEMS sensor are analyzed, common noise models are extracted, common abnormal data are actively filtered, automatic elimination and filling of abnormal points are achieved, and the influence of the measured abnormal data on the overall calculation result is prevented.

The MEMS sensor is acceleration sensor, measures through the MEMS sensor, whether the breaker switch moves, the switch all has the vibration of certain range, and the action of divide-shut brake relay also can lead to the vibration that the measuring point produced certain range simultaneously, simultaneously because of the gesture and the gravity reason of installation back sensor, the installation height above sea level is different, and the sensor has certain initial acceleration to this initial value is still not necessarily the same. Therefore, the acceleration calculation preset time is calculated to be 3ms through the switch auxiliary position action signal, the coil current recording value and the acceleration sudden change value, 3ms before the on-off of the switch contact of the circuit breaker is used as the contact stroke action starting point and the acceleration calculation starting point, the MEMS sensor collects the acceleration data before the action of the switch contact of the circuit breaker, and the initial value of the sensor is calculated after the sudden change filtering processing is carried out on the acceleration data.

After the operation, because the switch model is different, the switch contact motion acceleration degree curve is different, and switch structure reason can lead to the switch to produce the vibration volume of all directions when moving simultaneously, through to different models, especially different theory of operation, through high accuracy linear displacement sensor, carry out contrast test and data calibration, correction to improve measurement accuracy. When the breaker acts, the tripping mechanism acts, the energy storage spring releases, the other energy storage spring compresses, the measured value is greatly fluctuated under the conditions of impact at the closing moment of the switch closing action and the like (the conditions have short action time, so strategy filtering can be adopted), errors are accumulated in the integral calculation process, the characteristics of singular points under the common conditions are found out by analyzing the vibration under the conditions and comparing the vibration with the measured data of the high-precision linear displacement sensor, and a noise model of the singular points is extracted. And (3) carrying out average filtering on the acceleration, the calculated speed and the calculated displacement in the characteristic processes to remove the abrupt variable mode and eliminate the abnormal influence.

The sensor is influenced by external environment, the characteristics of the sensor, power supply quality and other factors, abnormal data are inevitably generated, the abnormal data usually have the characteristic of white noise, the output value of the MEMS acceleration sensor is acceleration, the change range of the action value is large, the abnormal data are difficult to remove by a conventional filtering algorithm, and larger calculation deviation is easily caused due to integral reasons. And comparing the output results of the high-precision linear displacement sensors, and adjusting Kalman filtering calculation parameters to achieve the purposes of improving the validity and precision of measurement data and further improving the measurement accuracy.

Compared with the prior art, the breaker stroke monitoring device based on the MEMS sensor and the monitoring method thereof provided by the embodiment have the following beneficial effects: (1) through MEMS sensor, realize sensor miniaturization, realize the reliable installation in limited space, need not connect mounting and moving part simultaneously, reduce the installation degree of difficulty. (2) The fixing band and adjust knob realize quick installation. (3) By means of the singularity filtering algorithm and the Kalman filtering algorithm arranged in historical data, effectiveness and precision of measured data are improved, and measuring accuracy is improved. (4) The method is convenient and fast to use in the actual field, and the working efficiency is improved.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A circuit breaker stroke monitoring device based on MEMS sensor (5), characterized by comprising:

a MEMS sensor (5), the MEMS sensor (5) for monitoring circuit breaker travel data;

the fixing piece comprises an adjusting knob (6) and a fixing belt (1);

the fixing band (1) is provided with an MEMS sensor (5) which is used for forming a closed loop structure around an insulating pull rod of a circuit breaker to be tested;

the adjusting knob (6) is arranged on the fixing band (1) and used for adjusting the size of the closed loop structure.

2. A circuit breaker stroke monitoring device based on MEMS sensor (5) according to claim 1, characterized in that:

the fixed band (1) is sleeved with a first flexible pad (2) which is used for attaching the inner side of the first flexible pad to an insulating pull rod of the circuit breaker.

3. A circuit breaker stroke monitoring device based on MEMS sensor (5) as claimed in claim 1, characterized in that:

the fixing belt (1) is provided with a mounting box (4);

the MEMS sensor (5) is fixed in the mounting box (4).

4. A circuit breaker stroke monitoring device based on MEMS sensor (5) according to claim 3 characterized in that:

the fixing strap (1) is sleeved with a second flexible pad (3) which is connected with the fixing box at the outer side.

5. A circuit breaker stroke monitoring method based on a MEMS sensor, which is characterized in that the circuit breaker stroke monitoring device based on the MEMS sensor according to any one of claims 1 to 4 is used for circuit breaker stroke monitoring, and comprises the following steps:

6. The method for monitoring the stroke of the circuit breaker based on the MEMS sensor as recited in claim 5, wherein the process for acquiring the initial acceleration value of the MEMS sensor on the circuit breaker specifically comprises the following steps:

7. The circuit breaker stroke monitoring method based on the MEMS sensor as claimed in claim 6, wherein:

and calculating the action signal of the auxiliary switch, the coil current recording value and the acceleration sudden change value to obtain the preset time.

8. The circuit breaker stroke monitoring method based on the MEMS sensor as recited in claim 6, wherein the cleaning process specifically comprises:

constructing a noise model based on the change characteristics of singular points in the action period-acceleration curve;

9. The method for monitoring the stroke of the circuit breaker based on the MEMS sensor as recited in claim 8, wherein:

the singular point comprises an abnormal value generated by impact at the closing moment of the switch contact of the circuit breaker and vibration quantity generated when the switch contact of the circuit breaker acts.

10. The circuit breaker stroke monitoring method based on the MEMS sensor as recited in claim 8, wherein:

and adjusting Kalman filtering algorithm parameters based on the cleaned acceleration value and the comparison result of the cleaned moment corresponding to the cleaned acceleration value and the reference data, and constructing an acceleration change curve of the MEMS sensor.