CN111239562A - High-voltage motor insulation detection method and device - Google Patents
High-voltage motor insulation detection method and device Download PDFInfo
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- CN111239562A CN111239562A CN202010084418.0A CN202010084418A CN111239562A CN 111239562 A CN111239562 A CN 111239562A CN 202010084418 A CN202010084418 A CN 202010084418A CN 111239562 A CN111239562 A CN 111239562A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2688—Measuring quality factor or dielectric loss, e.g. loss angle, or power factor
- G01R27/2694—Measuring dielectric loss, e.g. loss angle, loss factor or power factor
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Abstract
The invention relates to the technical field of trip investigation, in particular to a high-voltage motor insulation detection method and device. The method comprises the following steps: the first experiment is used for detecting the conductive fouling on the surface of the high-voltage motor coil; and/or a second experiment for detecting the aging degree and the dielectric loss of the insulating layer of the high-voltage motor coil; and/or a third experiment for detecting the partial discharge amount inside the insulating layer of the high-voltage motor coil. All data acquisition is performed within the rated voltage range of the high-voltage motor, and the experiment is reliable and stable; no harm to client equipment; the operation is convenient and easy; the experimental time is short, and the whole experimental process is within one hour.
Description
Technical Field
The invention relates to the technical field of trip investigation, in particular to a high-voltage motor insulation detection method and device.
Background
The high-voltage motor insulation diagnosis is to judge the conductive fouling, the surface partial discharge, the partial damage and the insulation internal air gap state of the coil surface and the insulation internal partial discharge amount through experimental data, provide motor insulation state data for a client, and suggest the client to adopt a corresponding scheme for the use and maintenance of the current motor, so that the client knows the equipment state, and timely takes measures to reduce the risk and save the cost. The existing high-voltage motor insulation diagnosis technology is immature, equipment to be diagnosed is required to be sent to a laboratory for a voltage-withstanding experiment, the equipment is greatly damaged, the service life of the equipment is shortened, meanwhile, the time required by the existing voltage-withstanding experiment mode is very long, the detection efficiency is low, and the accuracy is not high.
Disclosure of Invention
The invention aims to provide a high-voltage motor insulation detection method and device to solve the problems. In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
in one aspect, the present application provides a method for detecting insulation of a high-voltage motor, where the method includes:
the first experiment is used for detecting the conductive fouling on the surface of the high-voltage motor coil;
and/or a second experiment for detecting the aging degree and the dielectric loss of the insulating layer of the high-voltage motor coil;
and/or a third experiment for detecting the partial discharge amount inside the insulating layer of the high-voltage motor coil.
Optionally, the first experiment comprises:
communicating a high-voltage motor coil to be detected with a direct-current power supply;
applying voltage within rated voltage to the high-voltage motor coil, and detecting parameters of the high-voltage motor coil in real time, wherein the parameters comprise a current value and a voltage value;
and calculating a polarization index PI and a leakage index LI according to the detected parameter drawing, and judging the surface condition and the insulation state of the high-voltage motor coil by judging the values of the polarization index PI and the leakage index LI.
Optionally, the calculating the polarization index PI includes:
calculating the resistance value of a high-voltage motor coil at a first moment when the high-voltage motor coil is communicated with a direct-current power supply and the resistance value of a high-voltage motor coil at a second moment when the high-voltage motor coil is communicated with the direct-current power supply according to the detected parameters, wherein the time span of the second moment is integral multiple of the time span of the first moment;
the polarization index is calculated by equation (1):
in the formula (1), PI is a polarization index, RNThe resistance value R of the high-voltage motor coil at the second moment is communicated with the direct-current power supply1The resistance value of the high-voltage motor coil at the first moment is the resistance value of the high-voltage motor coil communicated with the direct-current power supply;
and drawing a first current change graph by taking time as an abscissa and current as an ordinate.
Optionally, the calculating the leakage index LI includes:
when the high-voltage motor coil is communicated with the direct-current power supply, the connection between the high-voltage motor coil and the direct-current power supply is disconnected at a second moment; recording the current value of the high-voltage motor coil in real time;
calculating the leakage index by equation (2):
in the formula (2), LI is a leakage index, INThe current value, I, of the high-voltage motor coil at the second moment after the high-voltage motor coil is communicated with the direct-current power supplyPut NThe current value of the high-voltage motor coil at the third moment after the high-voltage motor coil is disconnected with the direct-current power supply; the time span of the second time is equal to the time span of the third time;
and drawing a second current change graph by taking time as an abscissa and current as an ordinate.
Optionally, the second experiment comprises:
the device comprises an alternating current experiment for detecting the aging degree of an insulating layer of a high-voltage motor coil and a dielectric loss experiment for detecting the dielectric loss of the high-voltage motor coil;
in the alternating current experiment, a third current change graph is drawn according to detected parameters, a first excitation point Pi1 is found, and the aging degree of the insulating layer of the high-voltage motor coil is judged according to the value of the first excitation point Pi1 and the increment △ I of the actual current under the rated voltage relative to the theoretical current;
in the dielectric loss experiment, a dielectric loss change diagram is drawn according to the detected parameters, and whether moisture is absorbed in the insulating layer of the high-voltage motor coil and the dielectric loss and/or the aging degree are/is judged according to the dielectric loss value and the change amplitude thereof.
Optionally, the ac power supply is a high voltage ac power supply, and the output voltage of the high voltage ac power supply gradually increases until the rated voltage of the high voltage motor.
Optionally, the alternating current experiment comprises:
communicating a high-voltage motor coil to be detected with an alternating current power supply;
the method comprises the steps that the output voltage of an alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise current values;
drawing a third current change graph by taking the voltage as an abscissa and the current as an ordinate according to the detected parameters;
drawing a current value corresponding to each voltage value under a theoretical state to obtain a first theoretical variation graph;
comparing the first theoretical variation graph with the third current variation graph to find a first excitation point Pi 1;
and calculating the current difference value delta I between the actual current under the rated voltage and the current under the theoretical state.
Optionally, the dielectric loss experiment comprises:
communicating a high-voltage motor coil to be detected with an alternating current power supply;
the output voltage of the alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise dielectric loss values;
drawing a dielectric loss change diagram by taking the voltage as a horizontal coordinate and the dielectric loss value as a vertical coordinate according to the dielectric loss value corresponding to each acquired voltage value;
drawing dielectric loss values corresponding to each voltage value under a theoretical state to obtain a second theoretical variation graph;
and comparing the second theoretical variation graph with the dielectric loss variation graph to judge whether the dielectric loss value is abnormal.
Optionally, the third experiment, comprising:
communicating a high-voltage motor coil to be detected with an alternating current power supply; the alternating current power supply is a high-voltage alternating current power supply, and the output voltage of the high-voltage alternating current power supply is gradually increased until the rated voltage of the high-voltage motor is reached;
the output voltage of the alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise discharge capacity;
according to the discharge amount corresponding to each collected voltage value, drawing a discharge amount change graph by taking the voltage as an abscissa and the discharge amount as an ordinate;
drawing the discharge amount corresponding to each voltage value under the theoretical state to obtain a third theoretical variation graph;
and comparing the third theoretical change chart with the discharge capacity change chart to judge whether the discharge capacity is abnormal.
On the other hand, the invention provides a high-voltage motor insulation state diagnosis device, which comprises a high-voltage power supply VCC, a transformer T, a voltage regulator TYB, a direct-current power supply U1, a dielectric loss instrument U2 and a local discharge instrument U3; a third switch S3 is arranged between the local discharge instrument U3 and the high-voltage motor coil to be detected, and a fourth switch S4 is arranged between the direct-current power supply U1 and the high-voltage motor coil to be detected.
The invention has the following beneficial effects:
all data acquisition is performed within the rated voltage range of the high-voltage motor, and the experiment is reliable and stable; no harm to client equipment; the operation is convenient and easy; the experimental time is short, and the whole experimental process is within one hour.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the embodiments of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic circuit diagram of a high-voltage motor insulation state diagnosis device according to an embodiment of the present invention;
FIG. 2 is a first graph of current variation according to an embodiment of the present invention;
FIG. 3 is a second graph of current change according to an embodiment of the present invention;
FIG. 4 is a third graph of current change as described in the example of the present invention;
FIG. 5 is a graph of dielectric loss variation according to an embodiment of the present invention;
fig. 6 is a graph showing the change in the discharge amount in the example of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
The embodiment provides a high-voltage motor insulation detection method which comprises a first experiment for detecting conductive fouling on the surface of a high-voltage motor coil.
The first experiment includes step S110, step S120, and step S130.
Step S110: communicating a high-voltage motor coil to be detected with a direct-current power supply;
step S120: applying voltage within rated voltage to the high-voltage motor coil, and detecting parameters of the high-voltage motor coil in real time, wherein the parameters comprise a current value and a voltage value; automatically drawing by using a drawing instrument, wherein the drawn graph can judge the surface fouling type according to whether the curve is smooth or not;
step S130: and calculating a polarization index PI and a leakage index LI according to the detected parameter drawing, and judging the surface condition and the insulation state of the high-voltage motor coil by judging the values of the polarization index PI and the leakage index LI.
Optionally, the high voltage motor coil is a stator coil.
Optionally, the step S130 may further include a sub-step S1301, a sub-step S1302, and a sub-step S1303.
Substep S1301: calculating the resistance value of a high-voltage motor coil at a first moment when the high-voltage motor coil is communicated with a direct-current power supply and the resistance value of a high-voltage motor coil at a second moment when the high-voltage motor coil is communicated with the direct-current power supply according to the detected parameters, wherein the time span of the second moment is integral multiple of the time span of the first moment;
substep S1302: the polarization index is calculated by equation (1):
in the formula (1), PI is a polarization index, RNFor high-voltage motor windings at a second moment in time in which the high-voltage motor windings are in communication with a DC power supplyResistance value, R1The resistance value of the high-voltage motor coil at the first moment is the resistance value of the high-voltage motor coil communicated with the direct-current power supply;
substep S1303: with time as an abscissa and current as an ordinate, a first current change graph is drawn, and please refer to fig. 2.
The first time may be the 1 st minute and the second time may be the 10 th minute, i.e., in formula (1), RNThe resistance value, R, of the coil at the 10 th minute when the coil is communicated with a high-voltage power supply1The resistance value of the coil at the 1 st minute when the coil is communicated with the high-voltage power supply. When the PI is larger than or equal to 2, the motor is in a normal state, and no risk exists; when PI is present<2, it indicates that there is an abnormality such as moisture absorption or contamination on the coil surface, and there is a risk of operation.
Optionally, the step S130 may further include a sub-step S1304, a sub-step S1305, and a sub-step S1306.
Substep S1304: when the high-voltage motor coil is communicated with the direct-current power supply, the connection between the high-voltage motor coil and the direct-current power supply is disconnected at a second moment; recording the current value of the high-voltage motor coil in real time;
substep S1305: calculating the leakage index by equation (2):
in the formula (2), LI is a leakage index, INThe current value, I, of the high-voltage motor coil at the second moment after the high-voltage motor coil is communicated with the direct-current power supplyPut NThe current value of the high-voltage motor coil at the third moment after the high-voltage motor coil is disconnected with the direct-current power supply; the time span of the second time is equal to the time span of the third time;
substep S1306: with time as the abscissa and current as the ordinate, a second current variation graph is drawn, and please refer to fig. 3.
The second time may be 10 minutes, and the third time may be 10 minutes, i.e. in formula (2), INThe current value of the coil at the 10 th minute after the coil is communicated with a high-voltage power supply, IPut NThe current value of the coil at the 10 th minute after the coil is disconnected from the high voltage power supply is shown. When the LI is less than or equal to 30, the motor is in a normal condition and has no risk; when LI is present>At 30, it indicates that there is an abnormality such as moisture absorption or contamination on the coil surface, and there is a risk of operation.
The first experiment is a direct current absorption experiment, the direct current absorption experiment is that a high-voltage direct current power supply is added to a coil, current is generated in a direct current loop, and the current is related to moisture absorption and conductive fouling on the surface of the coil; however, because different motors have different capacities, the magnitude of current cannot be used singly to judge the quality, so that the polarization index and the leakage index are adopted to judge the state of the direct current absorption experiment.
When the values of PI and LI both indicate that the motor is in a normal state, the surface of the motor coil does not have the abnormality of moisture absorption or stain and the like, and the running risk does not exist. When any one or two values of the PI and the LI are in an abnormal state, the surface motor is in the abnormal state, the surface of the motor coil has the abnormality such as moisture absorption or stain, and the operation risk exists.
The first time is 1 minute, the second time is 10 minutes, and the third time is 10 minutes.
As another embodiment, the present embodiment provides a method for detecting insulation of a high voltage motor, where the method includes a second experiment for detecting aging degree and dielectric loss of an insulation layer of a coil of the high voltage motor.
The second experiment comprises an alternating current experiment for detecting the aging degree of the insulating layer of the high-voltage motor coil and a dielectric loss experiment for detecting the dielectric loss of the high-voltage motor coil;
in the alternating current experiment, a third current change graph is drawn according to detected parameters, a first excitation point Pi1 is found, and the aging degree of the insulating layer of the high-voltage motor coil is judged according to the value of the first excitation point Pi1 and the increment △ I of the actual current under the rated voltage relative to the theoretical current;
in the dielectric loss experiment, a dielectric loss change diagram is drawn according to the detected parameters, and whether moisture is absorbed in the insulating layer of the high-voltage motor coil and the dielectric loss and/or the aging degree are/is judged according to the dielectric loss value and the change amplitude thereof.
Optionally, the ac power supply is a high voltage ac power supply, and the output voltage of the high voltage ac power supply gradually increases until the rated voltage of the high voltage motor.
Optionally, the alternating current experiment may further include step S211, step S212, step S213, step S214, step S215, and step S216.
Step S211: communicating a high-voltage motor coil to be detected with an alternating current power supply;
step S212: the method comprises the steps that the output voltage of an alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise current values;
step S213: according to the detected parameters, the voltage is used as an abscissa and the current is used as an ordinate to draw a third current variation graph, and the third current variation graph refers to fig. 4;
step S214: drawing a current value corresponding to each voltage value under a theoretical state to obtain a first theoretical variation graph;
step S215: comparing the first theoretical variation graph with the third current variation graph to find a first excitation point Pi 1;
step S216: and calculating the current difference value delta I between the actual current under the rated voltage and the current under the theoretical state.
When AC is applied to the coil, the instrument measures the current in the line, the current value and the voltage value are in a direct proportion relation under normal conditions, but the current value is suddenly increased due to gradual discharge of an internal air gap after reaching a critical value, the voltage value under the sudden increase is a first excitation point Pi1, and the difference value delta I between the current value under the rated voltage and the theoretical non-discharge state reflects the aging degree of the coil.
When the rated voltage of the motor is 6KV, in the substep S2031, the voltages output by the high-voltage power supply are sequentially: 1.2KV, 1.5KV, 1.8KV, 2.1KV, 2.4KV, 2.7KV, 3.0KV, 3.3KV, 3.6KV, 3.9KV, 4.2KV, 4.5KV, 4.8KV, 5.1KV, 5.4KV, 5.7KV and 6.0 KV. And drawing a current change curve through the collected currents under different voltages, finding out a first excitation point Pi1, and calculating a current difference value delta I between the current under the rated voltage and the current under the theoretical state.
When the rated voltage is 6KV, Pi1 is better than or equal to the rated voltage/1.732, namely when Pi1 is better than or equal to 3.464KV, the aging degree of the high-voltage motor is low, and no operation risk exists; when Pi1<3.464KV indicates that the high voltage motor is aged to a high degree, there is an operational risk. When the delta I is less than or equal to 8% of the theoretical current under the rated voltage, the high-voltage motor is good, the aging degree of the high-voltage motor is low, and no operation risk exists; when the delta I is larger than 8% of the theoretical current under the rated voltage, the aging degree of the high-voltage motor is high, and the running risk exists.
Optionally, the dielectric loss experiment may further include step S221, step S222, step S223, step S224, and step S225.
Step S221: communicating a high-voltage motor coil to be detected with an alternating current power supply;
step S222: the output voltage of the alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise dielectric loss values;
step S223: drawing a dielectric loss change graph by taking the voltage as an abscissa and the dielectric loss value as an ordinate according to the dielectric loss value corresponding to each acquired voltage value, wherein the dielectric loss change graph refers to fig. 5;
step S224: drawing dielectric loss values corresponding to each voltage value under a theoretical state to obtain a second theoretical variation graph;
step S225: and comparing the second theoretical variation graph with the dielectric loss variation graph to judge whether the dielectric loss value is abnormal.
Dielectric loss is dielectric loss generated by an insulating material under voltage, and the size of the dielectric loss is an important index for measuring the dielectric capacity of an insulating medium. Measuring the value of the dielectric loss coefficient is a very effective way to determine the insulation condition of electrical equipment. It can reflect a series of defects of insulation, such as insulation affected by moisture and dirt, and air gap discharge in insulation.
When the rated voltage of the motor is 6KV, in the substep S2041, the voltage output by the high-voltage power supply sequentially comprises 1.2KV, 1.5KV, 1.8KV, 2.1KV, 2.4KV, 2.7KV, 3.0KV, 3.3KV, 3.6KV, 3.9KV, 4.2KV, 4.5KV, 4.8KV, 5.1KV, 5.4KV, 5.7KV, and 6.0 KV., and a change curve of the dielectric loss value is drawn through the dielectric loss values collected at different voltages, as shown in fig. 5, tan δ 0, preferably 5%, △ tan δ 2, preferably 6.5%.
The △ tan delta 2 is the difference value of the dielectric loss value and the initial value under the rated voltage.
As another embodiment, the method for detecting insulation of a high-voltage motor according to this embodiment may further include a third experiment for detecting a partial discharge amount inside an insulation layer of a coil of the high-voltage motor.
Optionally, the third experiment includes step S310, step S320, step S330, step S340, and step S350.
Step S310: communicating a high-voltage motor coil to be detected with an alternating current power supply; the alternating current power supply is a high-voltage alternating current power supply, and the output voltage of the high-voltage alternating current power supply is gradually increased until the rated voltage of the high-voltage motor is reached;
step S320: the output voltage of the alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise discharge capacity;
step S330: according to the collected discharge amount corresponding to each voltage value, drawing a discharge amount change graph by taking the voltage as an abscissa and the discharge amount as an ordinate, wherein the drawn discharge amount change graph refers to fig. 6;
step S340: drawing the discharge amount corresponding to each voltage value under the theoretical state to obtain a third theoretical variation graph;
step S350: and comparing the third theoretical change chart with the discharge capacity change chart to judge whether the discharge capacity is abnormal.
The third experiment is a partial discharge experiment. Under the action of the electric field, the electric field strength of a partial region of an insulator in an insulation system reaches the breakdown field strength, and discharge occurs in the partial region, which is called partial discharge. Partial discharges occur only locally in the insulation and do not extend through the entire insulation, which affects the insulation life when partial discharges occur. Each time of discharge, impact of high-energy electrons or accelerated electrons, especially long-term partial discharge, can cause various physical effects and chemical reactions, such as breaking insulating chemical bonds to crack when charged particles impact the outer wall of a bubble, destroying insulating molecular structures, causing insulation deterioration and accelerating the insulation damage process. Significance of partial discharge determination: the insulation discharge state and whether the discharge exceeds the standard or not are determined, the insulation state is judged by the maximum discharge charge quantity, the maximum discharge charge quantity can reflect the local weak point of insulation, and the experiment can find the insulation local invisible defects and faults which cannot be detected by other insulation tests.
When the discharge capacity is less than or equal to 20000PC, the high-voltage motor has no operation risk; when the discharge amount is <20000PC, it indicates that the high voltage motor has an operation risk.
As another embodiment, the present embodiment provides a high voltage motor insulation detection method, including a first experiment for detecting conductive contamination on a surface of a coil of a high voltage motor; and a second experiment for detecting the aging degree and the dielectric loss of the insulating layer of the high-voltage motor coil; and a third experiment for detecting the local discharge amount inside the insulating layer of the high-voltage motor coil.
In another aspect, the present invention provides a device for diagnosing an insulation state of a high voltage motor, as shown in fig. 1, the device includes a high voltage power source VCC, a transformer T, a voltage regulator TYB, a dc power source U1, a dielectric loss meter U2, and a local discharge meter U3; a third switch S3 is arranged between the local discharge instrument U3 and the high-voltage motor coil to be detected, and a fourth switch S4 is arranged between the direct-current power supply U1 and the high-voltage motor coil to be detected. The diagnostic device provided by the embodiment is used for realizing the diagnostic method.
The high-voltage power supply VCC is used for providing high-voltage alternating-current voltage.
The transformer T and the voltage regulator TYB are used for controlling the output voltage of the high-voltage power supply VCC, the input voltage of the transformer T is 380V, the output voltage is 12KV, the voltage regulator can manually realize the voltage regulation of 0-12KV, and the relevant numerical values under any voltage can be conveniently read.
The direct current power supply U1 can realize the direct current output of 0-12KV, can be charged by alternating current or direct current, and can set the experiment voltage according to the requirements of the experiment object.
The dielectric loss instrument U2 is also called an AC dielectric loss tester, and can read a voltage value, a current value, an introduction value and a capacitance value under any voltage.
The partial discharge instrument U3 is used for measuring the maximum discharge capacity of the experimental object under a certain voltage.
Optionally, the device may further include a plotter, and the voltage and the current in the experimental process are printed on a drawing in a graph manner, so that the voltage and the current at a certain time can be read, the resistance value at the time point can be calculated, and the surface state of the coil can be judged by observing the current graph.
When the dc absorption experiment is performed, the fourth switch S4 is closed, and the first switch S1, the second switch S2, and the third switch S3 are all opened.
When an alternating current experiment and a dielectric loss experiment are carried out, the first switch S1 is closed, and the second switch S2, the third switch S3 and the fourth switch S4 are all opened. The alternating current experiment and the dielectric loss experiment can be carried out independently or simultaneously.
When a partial discharge experiment is performed, the second switch S2 and the third switch S3 are simultaneously closed, and the first switch S1 and the fourth switch S4 are both opened.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A high-voltage motor insulation detection method is characterized by comprising the following steps:
the first experiment is used for detecting the conductive fouling on the surface of the high-voltage motor coil;
and/or a second experiment for detecting the aging degree and the dielectric loss of the insulating layer of the high-voltage motor coil;
and/or a third experiment for detecting the partial discharge amount inside the insulating layer of the high-voltage motor coil.
2. The high-voltage motor insulation detection method according to claim 1, wherein the first experiment comprises:
communicating a high-voltage motor coil to be detected with a direct-current power supply;
applying voltage within rated voltage to the high-voltage motor coil, and detecting parameters of the high-voltage motor coil in real time, wherein the parameters comprise a current value and a voltage value;
and calculating a Polarization Index (PI) and a Leakage Index (LI) according to the detected parameter drawing, and judging the surface condition and the insulation state of the high-voltage motor coil by judging the values of the Polarization Index (PI) and the Leakage Index (LI).
3. The high-voltage motor insulation detection method according to claim 2, characterized in that: the calculating Polarization Index (PI) comprises:
calculating the resistance value of a high-voltage motor coil at a first moment when the high-voltage motor coil is communicated with a direct-current power supply and the resistance value of a high-voltage motor coil at a second moment when the high-voltage motor coil is communicated with the direct-current power supply according to the detected parameters, wherein the time span of the second moment is integral multiple of the time span of the first moment;
the polarization index is calculated by equation (1):
in the formula (1), PI is a polarization index, RNA high-voltage motor at the second moment for connecting the coil of the high-voltage motor with the DC power supplyResistance value of coil, R1The resistance value of the high-voltage motor coil at the first moment is the resistance value of the high-voltage motor coil communicated with the direct-current power supply;
and drawing a first current change graph by taking time as an abscissa and current as an ordinate.
4. The high-voltage electrical machine insulation detection method according to claim 2, wherein said calculating a Leakage Index (LI) comprises:
when the high-voltage motor coil is communicated with the direct-current power supply, the connection between the high-voltage motor coil and the direct-current power supply is disconnected at a second moment; recording the current value of the high-voltage motor coil in real time;
calculating the leakage index by equation (2):
in the formula (2), LI is a leakage index, INThe current value, I, of the high-voltage motor coil at the second moment after the high-voltage motor coil is communicated with the direct-current power supplyPut NThe current value of the high-voltage motor coil at the third moment after the high-voltage motor coil is disconnected with the direct-current power supply; the time span of the second time is equal to the time span of the third time;
and drawing a second current change graph by taking time as an abscissa and current as an ordinate.
5. The high-voltage motor insulation detection method according to claim 1, wherein the second experiment comprises:
the device comprises an alternating current experiment for detecting the aging degree of an insulating layer of a high-voltage motor coil and a dielectric loss experiment for detecting the dielectric loss of the high-voltage motor coil;
in the alternating current experiment, a third current change graph is drawn according to detected parameters, a first excitation point (Pi1) is found, and the aging degree of the insulating layer of the high-voltage motor coil is judged according to the value of the first excitation point (Pi1) and the current difference value (delta I) between the actual current under the rated voltage and the theoretical state;
in the dielectric loss experiment, a dielectric loss change diagram is drawn according to the detected parameters, and whether moisture is absorbed in the insulating layer of the high-voltage motor coil and the dielectric loss and/or the aging degree are/is judged according to the dielectric loss value and the change amplitude thereof.
6. The high-voltage motor insulation detection method according to claim 5, characterized in that: the alternating current power supply is a high-voltage alternating current power supply, and the output voltage of the high-voltage alternating current power supply gradually rises until the rated voltage of the high-voltage motor.
7. The method for detecting the insulation of the high-voltage motor according to claim 6, wherein the alternating current experiment comprises:
communicating a high-voltage motor coil to be detected with an alternating current power supply;
the method comprises the steps that the output voltage of an alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise current values;
drawing a third current change graph by taking the voltage as an abscissa and the current as an ordinate according to the detected parameters;
drawing a current value corresponding to each voltage value under a theoretical state to obtain a first theoretical variation graph;
comparing the first theoretical variation graph with the third current variation graph to find a first excitation point (Pi 1);
and calculating the difference value (delta I) between the actual current under the rated voltage and the current under the theoretical state.
8. The insulation detection method for the high-voltage motor according to claim 6, wherein the dielectric loss test comprises:
communicating a high-voltage motor coil to be detected with an alternating current power supply;
the output voltage of the alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise dielectric loss values;
drawing a dielectric loss change diagram by taking the voltage as a horizontal coordinate and the dielectric loss value as a vertical coordinate according to the dielectric loss value corresponding to each acquired voltage value;
drawing dielectric loss values corresponding to each voltage value under a theoretical state to obtain a second theoretical variation graph;
and comparing the second theoretical variation graph with the dielectric loss variation graph to judge whether the dielectric loss value is abnormal.
9. The insulation detection method for the high-voltage motor according to claim 1, wherein the third experiment comprises:
communicating a high-voltage motor coil to be detected with an alternating current power supply; the alternating current power supply is a high-voltage alternating current power supply, and the output voltage of the high-voltage alternating current power supply is gradually increased until the rated voltage of the high-voltage motor is reached;
the output voltage of the alternating current power supply is increased once per liter, and parameters of a primary high-voltage motor coil are collected, wherein the parameters comprise discharge capacity;
according to the discharge amount corresponding to each collected voltage value, drawing a discharge amount change graph by taking the voltage as an abscissa and the discharge amount as an ordinate;
drawing the discharge amount corresponding to each voltage value under the theoretical state to obtain a third theoretical variation graph;
and comparing the third theoretical change chart with the discharge capacity change chart to judge whether the discharge capacity is abnormal.
10. A high-voltage motor insulation state diagnostic device is characterized in that: the diagnosis device comprises a high-voltage power supply (VCC), a transformer (T), a voltage regulator (TYB), a direct-current power supply (U1), a dielectric loss instrument (U2) and a local discharge instrument (U3); a third switch (S3) is arranged between the local discharge instrument (U3) and the high-voltage motor coil to be detected, and a fourth switch (S4) is arranged between the direct-current power supply (U1) and the high-voltage motor coil to be detected.
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| WO2022149956A1 (en) * | 2021-01-11 | 2022-07-14 | 고려대학교 산학협력단 | Motor capable of insulation diagnosis, motor control circuit, and method for diagnosing insulation of motor using motor control circuit |
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