CN113985270A - Method, system and medium for detecting switching time sequence of on-load tap-changer - Google Patents
Method, system and medium for detecting switching time sequence of on-load tap-changer Download PDFInfo
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- CN113985270A CN113985270A CN202111291894.0A CN202111291894A CN113985270A CN 113985270 A CN113985270 A CN 113985270A CN 202111291894 A CN202111291894 A CN 202111291894A CN 113985270 A CN113985270 A CN 113985270A
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Abstract
The invention discloses a method, a system and a medium for detecting the switching time sequence of an on-load tap-changer, wherein the method comprises the following steps: according to the invention, under the condition of DC1A load current, the switching is executed after the electrical connection wires of the single/double-side main contact and the single/double-side main on-off contact are selectively disconnected, and voltage signals at two ends of the on-load tap-changer in the switching process are collected; extracting characteristic points of corresponding voltage signals, and thus measuring the on-off time sequence of all the contacts; under the condition of DC5A load current, normally executing on-load tap-changer switching, and collecting voltage signals in the switching process; and extracting characteristic parameters of corresponding voltage signals, and measuring the electrical connection point, the electrical disconnection point, the mechanical contact point, the mechanical disconnection point and the corresponding arcing interval of the single/double-side main on-off contact and the single/double-side transition contact. The method provided by the invention can improve the completeness and the accuracy of the on-load tap-changer contact switching time sequence detection.
Description
Technical Field
The invention relates to the technical field of on-load tap changers of transformers, in particular to a method and a system for detecting switching time sequence of an on-load tap changer.
Background
When the power system operates, the voltage of the bus changes due to the change of the load, and a voltage deviation is generated between the actual voltage of the bus and the rated voltage. Power systems have stringent requirements for the degree of voltage deviation, and thus, a technique for adjusting the bus voltage is required. On-load tap changers are used more and more widely to adjust the voltage of an electrical power system without interruption by switching taps of a power transformer under a load condition.
In recent years, power failure accidents caused by electrical contact faults of on-load tap changers have been frequently reported, and mechanical faults and electrical faults are main factors causing the faults of the on-load tap changers.
In the switching process of the on-load tap-changer, mechanical abrasion and electrical erosion of the contact are involved, poor contact and increased contact resistance between the contacts can be caused, even the switching time sequence of the contacts is changed, and the operation reliability of the on-load tap-changer is seriously reduced.
However, the detection method for the switching state of the on-load tap-changer is quite limited. The traditional mechanical state detection method utilizes vibration signals to realize stethoscope-type detection on the mechanical state of the on-load tap-changer, is one of the widely applied monitoring and diagnosis methods at present, but the mechanical state cannot directly reflect the electrical state and cannot visually detect the electrical performance parameters of each contact. Most of traditional direct current tests are carried out under the condition of DC1A current load, although an electric signal of the on-load tap-changer can be detected, the arcing condition cannot be achieved, the direct current tests are far from the actual operation condition of the on-load tap-changer, only the on-off states of part of contacts can be detected, and whether the on-off states of all the contacts have defects or not cannot be detected.
Disclosure of Invention
The purpose of the invention is: the method and the system for detecting the switching time sequence of the on-load tap-changer are provided, and can solve the problems in the prior art.
In order to achieve the above object, the present invention provides a method for detecting a switching timing sequence of an on-load tap-changer, comprising:
the method comprises the following steps of constructing a detection circuit of the switching time sequence of the on-load tap-changer, wherein the detection circuit comprises: an on-load tap-changer and an adjustable constant current source; a single-side main contact, a single-side main on-off contact, a single-side transition contact, a double-side main on-off contact and a double-side main contact are arranged in the on-load tap changer; the output current of the constant current source includes: 1A or 5A;
according to detection circuitry, it is right on-load tap-changer carries out the preliminary survey, obtains on-load tap-changer's two sets of preliminary survey voltage waveforms, wherein, the preliminary survey specifically is: adjusting the constant current source to output DC1A constant current, so that the on-load tap-changer carries out switching test, and obtaining the initial test voltage waveform of the first group of on-load tap-changers; disconnecting the single-side main on-off contact and the double-side main on-off contacts, and performing switching test on the on-load tap-changer to obtain an initial test voltage waveform of a second group of on-load tap-changers;
judging whether the trends of the first group of initial voltage waveforms and the second group of initial voltage waveforms are the same or not, and if not, determining the switching time sequence of the on-load tap-changer according to the two groups of initial voltage waveforms; if the voltage waveform is the same as the voltage waveform of the on-load tap-changer, performing accurate measurement on the on-load tap-changer according to the detection circuit to obtain an accurate measurement voltage waveform of the on-load tap-changer, wherein the accurate measurement specifically comprises the following steps: disconnecting the single-side main contact, the single-side main on-off contact, the double-side main on-off contact and the double-side main contact, and performing switching test on the on-load tap-changer to obtain a group of accurate voltage waveform of the on-load tap-changer;
and determining the switching time sequence of the on-load tap-changer according to the first group of initial voltage waveforms, the second group of initial voltage waveforms and the fine voltage waveforms.
Further, after the step of determining the switching timing sequence of the on-load tap-changer according to the initial voltage waveform and the fine voltage waveform, the method further includes:
adjusting the DC5A constant current output by the adjustable constant current source to enable the on-load tap-changer to carry out switching test, and collecting voltage waveform data in the switching process;
and extracting characteristic parameters according to the voltage waveform to obtain an electrical connection point, an electrical disconnection point, a mechanical contact point, a mechanical disconnection point and a corresponding arcing interval of a main on-off contact and a transition contact of the on-load tap-changer.
Further, the characteristic parameters include: the rebound time and the breaking time of the switch in the switching process.
Further, the detection circuit further comprises an acquisition circuit, wherein the acquisition circuit comprises: the voltage regulating circuit is used for acquiring a voltage signal of the on-load tap-changer and sending the voltage signal to the AD converter, and the AD converter, the singlechip and the display module are sequentially connected.
Further, determining the switching timing of the on-load tap-changer according to the preliminary voltage waveform and the fine voltage waveform comprises:
it is right initially survey the voltage waveform and accurately survey the voltage waveform and extract the characteristic point, obtain initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform, wherein, initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform and include: the moment of abrupt change of voltage;
and determining the switching time sequence of the on-load tap-changer according to the characteristic points of the primary voltage waveform and the fine voltage waveform.
The invention also provides a system for detecting the switching time sequence of the on-load tap-changer, which comprises: the system comprises a construction module, a primary measurement module, a fine measurement module and a switching time sequence module, wherein the construction module is used for constructing a time sequence of a primary measurement module;
the building module is used for building a detection circuit of an on-load tap-changer switching time sequence, wherein the detection circuit comprises: an on-load tap-changer and an adjustable constant current source; a single-side main contact, a single-side main on-off contact, a single-side transition contact, a double-side main on-off contact and a double-side main contact are arranged in the on-load tap changer; the output current of the constant current source includes: 1A or 5A;
the initial measurement module is used for according to detection circuitry is right on-load tap-changer carries out initial measurement, obtains on-load tap-changer's two sets of initial measurement voltage waveforms, wherein, initial measurement specifically is: adjusting the constant current source to output DC1A constant current, so that the on-load tap-changer carries out switching test, and obtaining initial test voltage waveforms of a group of on-load tap-changers; disconnecting the single-side main on-off contact and the double-side main on-off contacts to perform switching test on the on-load tap-changer to obtain a group of initial test voltage waveforms of the on-load tap-changer;
the fine measurement module is used for determining whether the trends of the first group of initial measurement voltage waveforms and the second group of initial measurement voltage waveforms are the same or not, and if not, determining the switching time sequence of the on-load tap-changer according to the two groups of initial measurement voltage waveforms; if the voltage waveform is the same as the voltage waveform of the on-load tap-changer, performing accurate measurement on the on-load tap-changer according to the detection circuit to obtain an accurate measurement voltage waveform of the on-load tap-changer, wherein the accurate measurement specifically comprises the following steps: disconnecting the single-side main contact, the single-side main on-off contact, the double-side main on-off contact and the double-side main contact, and performing switching test on the on-load tap-changer to obtain a group of accurate voltage waveform of the on-load tap-changer;
and the switching time sequence module is used for determining the switching time sequence of the on-load tap-changer according to the first group of initial voltage waveforms, the second group of initial voltage waveforms and the accurate voltage waveforms.
Further, the system further comprises: the parameter acquisition module is used for adjusting the DC5A constant current output by the adjustable constant current source, so that the on-load tap-changer carries out switching test, and voltage waveform data in the switching process are acquired;
and extracting characteristic parameters according to the voltage waveform to obtain an electrical connection point, an electrical disconnection point, a mechanical contact point, a mechanical disconnection point and a corresponding arcing interval of a main on-off contact and a transition contact of the on-load tap-changer.
Further, the characteristic parameters include: the rebound time and the breaking time of the switch in the switching process.
Further, the switching timing module is specifically configured to:
it is right initially survey the voltage waveform and accurately survey the voltage waveform and extract the characteristic point, obtain initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform, wherein, initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform and include: the moment of abrupt change of voltage;
and determining the switching time sequence of the on-load tap-changer according to the characteristic points of the primary voltage waveform and the fine voltage waveform.
The invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the on-load tap changer switching timing detection method as defined in any of the above.
Compared with the prior art, the invention provides a method, a system and a medium for detecting the switching time sequence of an on-load tap-changer, which have the advantages that:
according to the invention, under the DC1A current load condition, the switching is executed after the electrical connection wires of the single/double-side main contact and the single/double-side main on-off contact are selectively disconnected, and voltage signals at two ends of the on-load tap-changer in the switching process are collected; extracting characteristic points of corresponding voltage signals, and thus measuring the on-off time sequence of all the contacts; under the DC5A current load condition, normally executing on-load tap-changer switching, and collecting voltage signals in the switching process; and extracting characteristic parameters of corresponding voltage signals, and measuring the electrical connection point, the electrical disconnection point, the mechanical contact point, the mechanical disconnection point and the corresponding arcing interval of the single/double-side main on-off contact and the single/double-side transition contact. The method provided by the invention can improve the completeness and the accuracy of the on-load tap-changer contact switching time sequence detection.
Drawings
Fig. 1 is a schematic flow chart of a method for detecting a switching timing sequence of an on-load tap changer according to the present invention;
FIG. 2 is a schematic diagram of a detection circuit according to the present invention;
fig. 3 is a schematic flow chart of the timing measurement of the switching of all contacts of the on-load tap changer according to the present invention;
FIG. 4 is a schematic diagram of feature point extraction for initial measurement in the present invention;
FIG. 5 is a schematic diagram of the extraction of feature points for fine measurement in the present invention;
FIG. 6 is a schematic diagram of feature parameter extraction in the present invention;
fig. 7 is a schematic structural diagram of a system for detecting a switching timing of an on-load tap changer according to the present invention.
Detailed Description
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 only a part of the embodiments of the present invention, and not all of the embodiments. 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 understood that the step numbers used herein are for convenience of description only and are not intended as limitations on the order in which the steps are performed.
It is to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The terms "comprises" and "comprising" indicate the presence of the described features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The term "and/or" refers to and includes any and all possible combinations of one or more of the associated listed items.
As shown in fig. 1, the method for detecting the switching timing sequence of the on-load tap-changer provided by the present invention includes steps S1-S4, and the specific steps are as follows:
s1, constructing a detection circuit of an on-load tap-changer switching sequence, wherein the detection circuit comprises: an on-load tap-changer and an adjustable constant current source; a single-side main contact, a single-side main on-off contact, a single-side transition contact, a double-side main on-off contact and a double-side main contact are arranged in the on-load tap changer; the output current of the constant current source includes: 1A or 5A.
Specifically, a detection circuit of the on-load tap-changer switching sequence is constructed according to the type of the on-load tap-changer, wherein the detection circuit comprises: adjustable constant current source, on-load tap-changer and acquisition circuit.
S2, according to detection circuitry is right on-load tap-changer carries out the preliminary survey, obtains on-load tap-changer' S two sets of preliminary survey voltage waveforms, wherein, the preliminary survey specifically is: adjusting the constant current source to output DC1A constant current, so that the on-load tap-changer carries out switching test, and obtaining the initial test voltage waveform of the first group of on-load tap-changers; and disconnecting the single-side main on-off contact and the double-side main on-off contacts, so that the on-load tap-changer is subjected to switching test to obtain the initial test voltage waveform of the second group of on-load tap-changers.
Specifically, according to the constructed detection circuit, the on-load tap-changer is subjected to initial measurement, and initial measurement voltage waveforms of two groups of on-load tap-changers are obtained.
S3, judging whether the trends of the first group of initial voltage waveforms and the second group of initial voltage waveforms are the same, and if not, determining the switching time sequence of the on-load tap-changer according to the two groups of initial voltage waveforms; if the voltage waveform is the same as the voltage waveform of the on-load tap-changer, performing accurate measurement on the on-load tap-changer according to the detection circuit to obtain an accurate measurement voltage waveform of the on-load tap-changer, wherein the accurate measurement specifically comprises the following steps: and disconnecting the single-side main contact, the single-side main on-off contact, the double-side main on-off contact and the double-side main contact, so that the on-load tap-changer is subjected to switching test to obtain a group of accurate voltage waveform of the on-load tap-changer.
Specifically, the steps are as follows: and judging whether the trends of the first group of initial voltage waveforms and the second group of initial voltage waveforms are the same, if so, executing the step S31, and if not, executing the step S32.
S31, according to the detection circuit, carrying out accurate measurement on the on-load tap-changer to obtain an accurate measurement voltage waveform of the on-load tap-changer, wherein the accurate measurement specifically comprises: and disconnecting the single-side main contact, the single-side main on-off contact, the double-side main on-off contact and the double-side main contact, so that the on-load tap-changer is subjected to switching test to obtain a group of accurate voltage waveform of the on-load tap-changer.
And S32, determining the switching time sequence of the on-load tap-changer according to the two groups of initial voltage waveforms.
And S4, determining the switching time sequence of the on-load tap-changer according to the first group of initial voltage waveforms, the second group of initial voltage waveforms and the fine voltage waveforms.
Specifically, it is right the initial survey voltage waveform and the accurate characteristic point of surveying the voltage waveform extract the characteristic point, obtain the initial survey voltage waveform and the accurate characteristic point of surveying the voltage waveform, wherein, the initial survey voltage waveform and the accurate characteristic point of surveying the voltage waveform include: the moment of abrupt change of voltage; and determining the switching time sequence of the on-load tap-changer according to the characteristic points of the primary voltage waveform and the fine voltage waveform.
In one embodiment of the present invention, after the step of determining the switching timing sequence of the on-load tap-changer according to the initial voltage waveform and the fine voltage waveform, the method further includes:
s5, adjusting the adjustable constant current source to output DC5A constant current, enabling the on-load tap-changer to carry out switching test, and collecting voltage waveform data in the switching process; and extracting characteristic parameters according to the voltage waveform to obtain an electrical connection point, an electrical disconnection point, a mechanical contact point, a mechanical disconnection point and a corresponding arcing interval of a main on-off contact and a transition contact of the on-load tap-changer.
In one embodiment of the present invention, the characteristic parameters include: the rebound time and the breaking time of the switch in the switching process.
In one embodiment of the present invention, the detection circuit further includes an acquisition circuit, wherein the acquisition circuit includes: the power conditioning circuit is used for acquiring a voltage signal of the on-load tap-changer and sending the voltage signal to the AD converter, and the AD converter, the singlechip and the display module are sequentially connected.
In an embodiment of the present invention, the determining a switching timing sequence of the on-load tap-changer according to the initial voltage waveform and the fine voltage waveform includes:
it is right initially survey the voltage waveform and accurately survey the voltage waveform and extract the characteristic point, obtain initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform, wherein, initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform and include: the moment of abrupt change of voltage;
and determining the switching time sequence of the on-load tap-changer according to the characteristic points of the primary voltage waveform and the fine voltage waveform.
For a better understanding of the present invention, it can be understood by the following specific examples:
the method for detecting the switching time sequence of the contacts of the on-load tap-changer is expressed by taking a CM type on-load tap-changer as an example, and specifically comprises the following steps:
the embodiment provides a method for detecting a switching state of an on-load tap-changer, and with reference to fig. 2, the method includes the following steps: the adjustable constant current source 1 excites the UU 'end of the on-load tap-changer 2 to be tested, and the voltage waveform of the UU' end is collected by the collection circuit 3; adjusting the output DC1A constant current of the adjustable constant current source 1, and carrying out initial test on the tested on-load tap-changer 2; judging whether the trends of the two groups of voltage waveforms collected in the initial test process are consistent, if not, determining the switching time sequence of all the contacts, and if so, executing accurate test; and (4) integrating three groups of voltage waveforms collected in the primary measurement process and the fine measurement process, extracting characteristic points of corresponding voltage signals, and determining the on-off time sequence of all contacts.
Adjusting the DC5A constant current output by the adjustable constant current source 1, executing the switching process and collecting the UU' end voltage waveform of the tested on-load tap-changer 2; according to the collected voltage waveform, characteristic parameters are extracted, parameters such as rebound time and breaking time of the tested on-load tap-changer 2 in the switching process can be obtained, and the electrical connection point, the electrical breaking point, the mechanical contact point, the mechanical breaking point and the corresponding arcing interval of the single/double-side main on-off contact and the single/double-side transition contact of the tested on-load tap-changer are tested. The output current of the adjustable constant current source 1 is 1A or 5A. The acquisition circuit 3 specifically includes: a voltage conditioning circuit 31, an AD converter 32, a singlechip 33 and a display module 34. The rebound time and the breaking time respectively specifically refer to the time from the contact voltage sudden change moment to the time when the contact is stabilized within an acceptable threshold value range in the closing process and the breaking process of the contact; the electrical connection point and the electrical disconnection point respectively specifically refer to the moment when the voltage of the contact is stabilized within an acceptable threshold range in the closing process and the disconnection process of the contact; the mechanical contact point and the mechanical breaking point respectively specifically refer to the sudden change time of the contact voltage in the closing process and the breaking process of the contact.
It should be noted that, for this embodiment, the transition resistance of the CM type on-load tap-changer is a single-side transition resistance and a double-side transition resistance from left to right in sequence, and the contact of the CM type on-load tap-changer is a single-side main contact K from left to right in sequenceAUnilateral main on-off contact K1Unilateral transition contact K2Bilateral transition contact K3Two, twoSide main on-off contact K4And a double-sided main contact KBThe initial state is the contact KAAnd K1In the closed state, due to the contact KAIs much less than the contact resistance of K1, although contact K isAAnd a contact K1Are all closed, but contact K1In a short-circuited state, the load current flows only through the contact KAAnd there are two possible switching sequences, respectively: kADisconnection, K2Closure, K1Disconnection, K3Closure, K2Disconnection, K4Closure, K3Disconnection, KBClosing; k2Closure, KADisconnection, K1Disconnection, K3Closure, K2Disconnection, K4Closure, KBClosure, K3And (5) disconnecting. Most CM type on-load tap-changer is the above-mentioned second kind of switching time sequence when leaving the factory, but because reasons such as contact mechanical wear and electrical erosion, the on-load tap-changer also can appear the above-mentioned first kind of switching time sequence after working for a period of time, the operational reliability of on-load tap-changer will be greatly reduced to the appearance of this kind of switching time sequence, but traditional on-load tap-changer detection method can't detect this kind of time sequence, this constitutes very big hidden danger.
Next, referring to fig. 3, the initial measurement specifically includes: executing a switching process, and collecting a voltage signal of the tested on-load tap-changer 2 in the switching process; will contact head K1、K4The switching process is executed again after the electric connecting line is broken, and the voltage signal of the tested on-load tap-changer 2 in the switching process is collected. The precise measurement comprises the following specific steps: will contact head KA、K1、K4、KBThe switching process is executed after the electric connecting line is broken, and the voltage signal of the tested on-load tap-changer 2 in the switching process is collected. The characteristic point extraction specifically refers to extracting the voltage mutation moment in the voltage waveform and determining the on-off moment of the corresponding contact.
It should be noted that, the purpose of determining whether two groups of voltage waveform trends collected in the initial test process are consistent after the initial test is as follows: and judging whether the switching time sequence of the tested on-load tap-changer 2 is the first switching time sequence or the second switching time sequence, if the trends are not consistent, the first switching time sequence is determined, and if the trends are consistent, the second switching time sequence is determined.
Referring to fig. 4 and the initial testing steps, if the on-load tap-changer 2 to be tested is in the first switching sequence, the contact K is in the switching process1Contact K at breaking2After the on-load tap-changer 2 is switched on, the voltage across the on-load tap-changer 2 is changed from contact voltage drop to voltage A across the single-side transition resistor; contact K3When the on-load tap-changer is switched on, the single-side transition resistor and the double-side transition resistor are connected in parallel, the divided voltage is halved, and the voltage at two ends of the on-load tap-changer 2 to be measured is changed into A/2; contact K2When the load tap switch is disconnected, the single-side transition resistor is cut off, and the voltage at the two ends of the measured load tap switch 2 is changed into A again; contact K4When in connection, due to contact K4The contact voltage drop of the double-side transition resistor is far less than the voltage at two ends of the double-side transition resistor, and the double-side transition resistor is contacted by a contact K4And short circuit occurs, and the voltage at two ends of the tested on-load tap-changer 2 is changed into contact voltage drop of the contact from the voltage A at two ends of the double-side transition resistor. At the contact K1、K4When the switching process is executed again after the electrical connection line is cut off, the contact KAWhen the load tap switch 2 is disconnected, the voltage at the two ends of the tested load tap switch is changed into open-circuit voltage (OCV) from contact voltage drop of the contacts because all the contacts are in a disconnected state; contact K2When the voltage is connected, the single-side transition resistor is connected, and the voltage at two ends of the tested on-load tap-changer 2 is changed from open-circuit voltage (OCV) to voltage A at two ends of the single-side transition resistor; contact K3When the load tap switch 2 is disconnected, all the contacts are in a disconnected state, and the voltage at the two ends of the tested load tap switch 2 is changed from the voltage A at the two ends of the double-side transition resistor to open-circuit voltage (OCV); contact KBWhen the on-load tap-changer 2 is switched on, the voltage across the on-load tap-changer 2 changes from Open Circuit Voltage (OCV) to contact voltage drop. From the above analysis, it can be seen that t in FIG. 41To t8Respectively corresponding to the contact KABreaking, K2Closure, K1Breaking, K3Closure, K2Breaking, K4Closure, K3Breaking, KBAnd at the breaking moment, the on-off time sequence of all the contacts in the first switching time sequence is measured.
Referring to fig. 5 and the above-mentioned fine measurement step, if the on-load tap-changer 2 under test is in the above-mentioned second switching sequence, the contact K is in the process of performing the switching process1At the time of breaking, due to K2After the on-load tap-changer 2 is switched on, the voltage across the on-load tap-changer 2 is changed from contact voltage drop to voltage A across the single-side transition resistor; contact K3When the on-load tap-changer is switched on, the single-side transition resistor and the double-side transition resistor are connected in parallel, the divided voltage is halved, and the voltage at two ends of the on-load tap-changer 2 to be measured is changed into A/2; contact K2When the load tap switch is disconnected, the single-side transition resistor is cut off, and the voltage at the two ends of the measured load tap switch 2 is changed into A again; contact K4When in connection, due to contact K4The contact voltage drop of the double-side transition resistor is far less than the voltage at two ends of the double-side transition resistor, and the double-side transition resistor is contacted by a contact K4And short circuit occurs, and the voltage at two ends of the tested on-load tap-changer 2 is changed into contact voltage drop of the contact from the voltage A at two ends of the double-side transition resistor. At the contact K1、K4When the switching process is executed again after the electrical connection line is cut off, the contact KADue to contact K during breaking2After the on-load tap-changer 2 is switched on, the voltage across the on-load tap-changer 2 is changed from contact voltage drop to voltage A across the single-side transition resistor; contact KBWhen in connection, due to contact KBThe contact voltage drop of the double-side transition resistor is far less than the voltage at two ends of the double-side transition resistor, and the double-side transition resistor is contacted by a contact KBShort circuit, voltage change between two ends of the on-load tap-changer 2 to be tested is contact KBContact pressure drop of (2). At the contact KA、K1、K4、KBWhen the switching process is executed again after the electrical connection line is cut off, the contact K2When the load tap switch is switched on, the single-side transition resistor is switched in, and the voltage at two ends of the tested load tap switch 2 is changed from Open Circuit Voltage (OCV) to voltage A at two ends of the single-side transition resistor; contact K3When the load tap switch 2 is disconnected, the double-side transition resistor is cut off, and the voltage A at the two ends of the double-side transition resistor is changed into open-circuit voltage (OCV). From the above analysis, it can be seen that t in FIG. 51From 'to t'8Respectively corresponding to the contact K2Closure, KABreaking, K1Breaking, K3Closure, K2Breaking, K4Closure, KBClosure, K3At the moment of the breaking, the cutting-off is carried out,at this point, the on-off sequence of all the contacts in the second switching sequence is measured.
It should be noted that, for this embodiment, the resistance value of the single/double-side transition resistor is about 6 Ω, and under the condition of DC1A load current, the highest voltage at two ends of the contact of the on-load tap-changer 2 to be tested in the switching process is 6V, and the arcing condition of the contact material cannot be achieved (the contact material is copper, and the arcing voltage is 12V), so there are no parameters such as an electrical connection point, an electrical disconnection point, and an arcing interval, and the voltage waveform contains fewer characteristic points, is clear and intuitive, and is convenient for accurately extracting the on-off time of the contact, and therefore, the adjustable constant current source 1 is adjusted to output 1A current to detect the on-off time sequence of all contacts of the on-load tap-changer. Under the condition of DC5A load current, the lowest voltage at two ends of a contact of the on-load tap-changer 2 to be tested is 15V in the switching process, and the arcing condition of a contact material is met, so when the working state of the on-load tap-changer 2 to be tested is changed, electric arcs are generated, the real operating condition of the on-load tap-changer is better met, the measured voltage waveform comprises a plurality of electrical characteristic parameters, and therefore the adjustable constant current source 1 is adjusted to output DC5A load current to measure the single/double-side main on-off contact K of the on-load tap-changer1/K4And single/double side transition contact K2/K3Electrical on-point, electrical off-point, mechanical contact point, mechanical off-point and arcing interval.
Next, referring to fig. 6, the bounce time and the breaking time refer to the time taken by the contact to stabilize within an acceptable threshold range from the moment when the contact voltage suddenly changes in the closing process and the breaking process, respectively. The electrical connection point and the electrical disconnection point respectively refer to the time when the voltage of the contact is stabilized within an acceptable threshold range in the closing process and the disconnection process of the contact. The mechanical contact point and the mechanical breaking point respectively specifically refer to the sudden change time of the contact voltage in the closing process and the breaking process of the contact. The threshold range specifically refers to plus or minus 5% of the transient steady-state voltage value at the corresponding stage.
Contact K1At the time of breaking, t3For the moment of sudden change of the voltage across the on-load tap-changer 2 to be measured, tb1For being tested to carryWhen the voltage at two ends of the tap switch 2 is stabilized at the transient steady-state voltage moment of the first stage, the contact K1Has a breaking time tb1－t3(ii) a Contact K3On time, t4For the moment of sudden change of the voltage across the on-load tap-changer 2 to be measured, tc1In order to stabilize the voltage at the two ends of the tested on-load tap-changer 2 at the transient steady-state voltage moment of the second stage, the contact K3Has a rebound time of tc1－t4(ii) a Contact K2At the time of breaking, t5For the moment of sudden change of the voltage across the on-load tap-changer 2 to be measured, tb2In order to stabilize the voltage at the two ends of the tested on-load tap-changer 2 at the third stage transient steady-state voltage moment, the contact K2Has a breaking time tb2－t5(ii) a Contact K4On time, t6For the moment of sudden change of the voltage across the on-load tap-changer 2 to be measured, tc2In order to stabilize the voltage at the two ends of the tested on-load tap-changer 2 at the fourth stage transient steady-state voltage moment, the contact K4Has a rebound time of tc2－t6. From the above analysis, it can be seen that t3、tb1、t4、tc1、t5、tb2、t6And tc2Respectively corresponding to the contact K1Mechanical breaking point and contact K1Electrical breaking point and contact K3Mechanical contact point and contact K3Electrical contact point, contact K2Mechanical breaking point and contact K2Electrical breaking point and contact K4Mechanical contact point and contact K4An electrical contact point, corresponding to an arcing interval of (t)3，tb1)、(t4，tc1)、(t5，tb2) And (t)6，tc2)。
Compared with the prior art, the method for detecting the switching time sequence of the on-load tap-changer has the beneficial effects that:
according to the invention, under the condition of DC1A load current, the switching is executed after the electrical connection wires of the single/double-side main contact and the single/double-side main on-off contact are selectively disconnected, and voltage signals at two ends of the on-load tap-changer in the switching process are collected; extracting characteristic points of corresponding voltage signals, and thus measuring the on-off time sequence of all the contacts; under the condition of DC5A load current, normally executing on-load tap-changer switching, and collecting voltage signals in the switching process; and extracting characteristic parameters of corresponding voltage signals, and measuring the electrical connection point, the electrical disconnection point, the mechanical contact point, the mechanical disconnection point and the corresponding arcing interval of the single/double-side main on-off contact and the single/double-side transition contact. The method provided by the invention can improve the completeness and the accuracy of the on-load tap-changer contact switching time sequence detection.
As shown in fig. 7, the present invention further provides a system 200 for detecting a switching timing of an on-load tap changer, including: the system comprises a construction module 201, a primary measurement module 202, a fine measurement module 203 and a switching time sequence module 204, wherein the construction module is used for constructing a time sequence;
the building module 201 is configured to build a detection circuit of a switching timing sequence of an on-load tap-changer, where the detection circuit includes: an on-load tap-changer;
the initial measurement module 202 is configured to perform initial measurement on the on-load tap-changer according to the detection circuit, so as to obtain two sets of initial measurement voltage waveforms of the on-load tap-changer, wherein the initial measurement specifically includes: connecting a single-side main contact and a single-side main on-off contact, and performing switching test on the on-load tap-changer to obtain a group of initial test voltage waveforms of the on-load tap-changer; disconnecting the single-side main on-off contact and the double-side main on-off contacts to perform switching test on the on-load tap-changer to obtain a group of initial test voltage waveforms of the on-load tap-changer;
the fine measurement module 203 is configured to determine whether trends of the first group of initial measurement voltage waveforms and the second group of initial measurement voltage waveforms are the same, and if not, determine a switching timing sequence of the on-load tap-changer according to the two groups of initial measurement voltage waveforms; if the voltage waveform is the same as the voltage waveform of the on-load tap-changer, performing accurate measurement on the on-load tap-changer according to the detection circuit to obtain an accurate measurement voltage waveform of the on-load tap-changer, wherein the accurate measurement specifically comprises the following steps: disconnecting the single-side main contact, the single-side main on-off contact, the double-side main on-off contact and the double-side main contact, and performing switching test on the on-load tap-changer to obtain a group of accurate voltage waveform of the on-load tap-changer;
and the switching time sequence module 204 is used for determining the switching time sequence of the on-load tap-changer according to the first group of initial voltage waveforms, the second group of initial voltage waveforms and the fine voltage waveforms.
In one embodiment of the present invention, the system further includes: the parameter obtaining module 205 is configured to adjust a constant current of the adjustable constant current source DC5A, perform a switching test on the on-load tap changer, and acquire voltage waveform data in a switching process;
and extracting characteristic parameters according to the voltage waveform to obtain an electrical connection point, an electrical disconnection point, a mechanical contact point, a mechanical disconnection point and a corresponding arcing interval of a main on-off contact and a transition contact of the on-load tap-changer.
In one embodiment of the present invention, the characteristic parameters include: the rebound time and the breaking time of the switch in the switching process.
In an embodiment of the present invention, the switching timing module 204 is specifically configured to:
it is right initially survey the voltage waveform and accurately survey the voltage waveform and extract the characteristic point, obtain initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform, wherein, initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform and include: the moment of abrupt change of voltage;
and determining the switching time sequence of the on-load tap-changer according to the characteristic points of the primary voltage waveform and the fine voltage waveform.
The invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the on-load tap changer switching timing detection method as defined in any of the above.
It should be noted that the computer program may be divided into one or more modules/units (e.g., computer program), and the one or more modules/units are stored in the memory and executed by the processor to implement the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used for describing the execution process of the computer program in the terminal device.
The above-mentioned embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, and 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. It should be understood that any modifications, equivalents, improvements and the like, which come within the spirit and principle of the invention, may occur to those skilled in the art and are intended to be included within the scope of the invention.
Claims (10)
1. A method for detecting switching time sequence of an on-load tap-changer is characterized by comprising the following steps:
the method comprises the following steps of constructing a detection circuit of the switching time sequence of the on-load tap-changer, wherein the detection circuit comprises: an on-load tap-changer and an adjustable constant current source; a single-side main contact, a single-side main on-off contact, a single-side transition contact, a double-side main on-off contact and a double-side main contact are arranged in the on-load tap changer; the output current of the constant current source includes: 1A or 5A;
according to detection circuitry, it is right on-load tap-changer carries out the preliminary survey, obtains on-load tap-changer's two sets of preliminary survey voltage waveforms, wherein, the preliminary survey specifically is: adjusting the constant current source to output DC1A constant current, so that the on-load tap-changer carries out switching test, and obtaining the initial test voltage waveform of the first group of on-load tap-changers; disconnecting the single-side main on-off contact and the double-side main on-off contacts, and performing switching test on the on-load tap-changer to obtain an initial test voltage waveform of a second group of on-load tap-changers;
judging whether the trends of the first group of initial voltage waveforms and the second group of initial voltage waveforms are the same or not, and if not, determining the switching time sequence of the on-load tap-changer according to the two groups of initial voltage waveforms; if the voltage waveform is the same as the voltage waveform of the on-load tap-changer, performing accurate measurement on the on-load tap-changer according to the detection circuit to obtain an accurate measurement voltage waveform of the on-load tap-changer, wherein the accurate measurement specifically comprises the following steps: disconnecting the single-side main contact, the single-side main on-off contact, the double-side main on-off contact and the double-side main contact, and performing switching test on the on-load tap-changer to obtain a group of accurate voltage waveform of the on-load tap-changer;
and determining the switching time sequence of the on-load tap-changer according to the first group of initial voltage waveforms, the second group of initial voltage waveforms and the fine voltage waveforms.
2. The on-load tap changer switching timing detection method of claim 1, further comprising, after the step of determining the switching timing of the on-load tap changer from the preliminary voltage waveform and the fine voltage waveform:
adjusting the DC5A constant current output by the adjustable constant current source to enable the on-load tap-changer to carry out switching test, and collecting voltage waveform data in the switching process;
and extracting characteristic parameters according to the voltage waveform to obtain an electrical connection point, an electrical disconnection point, a mechanical contact point, a mechanical disconnection point and a corresponding arcing interval of a main on-off contact and a transition contact of the on-load tap-changer.
3. The on-load tap changer switching timing detection method of claim 2, wherein the characteristic parameters comprise: the rebound time and the breaking time of the switch in the switching process.
4. The on-load tap changer switching timing detection method of claim 1, wherein the detection circuit further comprises an acquisition circuit, wherein the acquisition circuit comprises: the voltage regulating circuit is used for acquiring a voltage signal of the on-load tap-changer and sending the voltage signal to the AD converter, and the AD converter, the singlechip and the display module are sequentially connected.
5. The on-load tap changer switching timing detection method of claim 1, wherein determining the switching timing of the on-load tap changer from the preliminary voltage waveform and the fine voltage waveform comprises:
it is right initially survey the voltage waveform and accurately survey the voltage waveform and extract the characteristic point, obtain initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform, wherein, initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform and include: the moment of abrupt change of voltage;
and determining the switching time sequence of the on-load tap-changer according to the characteristic points of the primary voltage waveform and the fine voltage waveform.
6. An on-load tap-changer switching timing sequence detection system, comprising: a construction module, a primary measurement module, a fine measurement module and a switching sequence module, wherein,
the building module is used for building a detection circuit of an on-load tap-changer switching time sequence, wherein the detection circuit comprises: an on-load tap-changer and an adjustable constant current source; a single-side main contact, a single-side main on-off contact, a single-side transition contact, a double-side main on-off contact and a double-side main contact are arranged in the on-load tap changer; the output current of the constant current source includes: 1A or 5A;
the initial measurement module is used for according to detection circuitry is right on-load tap-changer carries out initial measurement, obtains on-load tap-changer's two sets of initial measurement voltage waveforms, wherein, initial measurement specifically is: adjusting the constant current source to output DC1A constant current, so that the on-load tap-changer carries out switching test, and obtaining initial test voltage waveforms of a group of on-load tap-changers; disconnecting the single-side main on-off contact and the double-side main on-off contacts to perform switching test on the on-load tap-changer to obtain a group of initial test voltage waveforms of the on-load tap-changer;
the fine measurement module is used for determining whether the trends of the first group of initial measurement voltage waveforms and the second group of initial measurement voltage waveforms are the same or not, and if not, determining the switching time sequence of the on-load tap-changer according to the two groups of initial measurement voltage waveforms; if the voltage waveform is the same as the voltage waveform of the on-load tap-changer, performing accurate measurement on the on-load tap-changer according to the detection circuit to obtain an accurate measurement voltage waveform of the on-load tap-changer, wherein the accurate measurement specifically comprises the following steps: disconnecting the single-side main contact, the single-side main on-off contact, the double-side main on-off contact and the double-side main contact, and performing switching test on the on-load tap-changer to obtain a group of accurate voltage waveform of the on-load tap-changer;
and the switching time sequence module is used for determining the switching time sequence of the on-load tap-changer according to the first group of initial voltage waveforms, the second group of initial voltage waveforms and the accurate voltage waveforms.
7. The on-load tap changer switching timing detection system of claim 6, further comprising: the parameter acquisition module is used for adjusting the DC5A constant current output by the adjustable constant current source, so that the on-load tap-changer carries out switching test, and voltage waveform data in the switching process are acquired;
and extracting characteristic parameters according to the voltage waveform to obtain an electrical connection point, an electrical disconnection point, a mechanical contact point, a mechanical disconnection point and a corresponding arcing interval of a main on-off contact and a transition contact of the on-load tap-changer.
8. The on-load tap changer switching timing detection system of claim 7, wherein the characteristic parameters comprise: the rebound time and the breaking time of the switch in the switching process.
9. The on-load tap changer switching timing detection system of claim 6, wherein the switching timing module is specifically configured to:
it is right initially survey the voltage waveform and accurately survey the voltage waveform and extract the characteristic point, obtain initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform, wherein, initially survey the voltage waveform and accurately survey the characteristic point of voltage waveform and include: the moment of abrupt change of voltage;
and determining the switching time sequence of the on-load tap-changer according to the characteristic points of the primary voltage waveform and the fine voltage waveform.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the on-load tap changer switching timing detection method according to any one of claims 1 to 5.
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