CN114200354B - Zero sequence CT polarity online detection method, system and equipment - Google Patents
Zero sequence CT polarity online detection method, system and equipment Download PDFInfo
- Publication number
- CN114200354B CN114200354B CN202210139618.0A CN202210139618A CN114200354B CN 114200354 B CN114200354 B CN 114200354B CN 202210139618 A CN202210139618 A CN 202210139618A CN 114200354 B CN114200354 B CN 114200354B
- Authority
- CN
- China
- Prior art keywords
- polarity
- zero
- zero sequence
- sequence
- bus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/72—Testing of electric windings
-
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The invention relates to the technical field of circuit verification, and discloses a zero sequence CT polarity online detection method, a zero sequence CT polarity online detection system and zero sequence CT polarity online detection equipment. The polarity detection method is characterized in that sampling data are obtained based on the operation of a common 10kV bus switching capacitor bank, the polarity of the zero sequence voltage variation of the bus is used as a reference, and is compared with the polarity of the zero sequence current variation of each branch to be detected, so that the polarity of each zero sequence CT is judged.
Description
Technical Field
The invention relates to the technical field of circuit verification, in particular to a zero sequence CT polarity online detection method, a zero sequence CT polarity online detection system and zero sequence CT polarity online detection equipment.
Background
In order to reduce the influence and loss on the safe and stable operation of the power grid after the ground fault occurs to the power grid, the power grid has the configuration requirement of zero sequence protection, and the reliable operation of the zero sequence protection is closely related to the polarity accuracy of a zero sequence CT (current transformer). A large number of feeder zero sequence CTs exist on the 10kV side of the transformer substation, and if the zero sequence CTs need to be checked one by one, a large number of manpower and material resources need to be consumed, so that hidden dangers are not easy to find.
In the prior art, when detecting the polarity of the zero-sequence CT, a current booster or a relay protection tester is used to output current to enable the current to pass through each zero-sequence CT in a power failure state of a transformer substation, so as to judge the polarity of the zero-sequence CT according to the phase and the magnitude of the obvious steady-state zero-sequence current when a single-phase ground fault occurs in a power grid, or a phase current transformer assembled by three phases is used to detect the polarity of the zero-sequence CT. The method must judge the polarity of the zero sequence CT when the earth fault occurs, and cannot detect the polarity of the zero sequence CT when the power grid normally operates. Because the probability of the power grid fault is low, the existing zero sequence CT polarity detection method cannot timely judge the polarity reverse error of the zero sequence CT wiring, which is not beneficial to the correct action of zero sequence protection when the power grid fault occurs.
Disclosure of Invention
The invention provides a zero sequence CT polarity online detection method, a zero sequence CT polarity online detection system and zero sequence CT polarity online detection equipment, which solve the technical problems that the existing zero sequence CT polarity detection method must judge the polarity of zero sequence CT when a ground fault occurs, and the judgment is not timely and a large amount of manpower and material resources are consumed.
The invention provides a zero sequence CT polarity online detection method in a first aspect, which comprises the following steps:
acquiring sampling data when a 10kV bus of a transformer substation is put into a compensation capacitor bank, wherein the sampling data comprises zero-sequence voltage waveforms of the 10kV bus corresponding to an input time period and zero-sequence current waveforms of all branches to be detected;
selecting a db wavelet function to perform one-layer wavelet decomposition on the zero sequence voltage waveform to obtain a corresponding wavelet decomposition coefficient;
when the wavelet decomposition coefficient is not constant to 0, decomposing and reconstructing a high-frequency band signal where a singular point of the zero-sequence voltage waveform is located, extracting a modulus maximum value of a multi-time wavelet coefficient from the reconstructed signal waveform, and calculating the zero-sequence voltage variation of the 10kV bus and the zero-sequence current variation of each branch to be detected at the sampling point where each modulus maximum value is located;
determining a variation threshold value according to each zero-sequence voltage variation, and taking a sampling point where a corresponding module maximum value of the zero-sequence voltage variation which is greater than the variation threshold value is located as a sampling point corresponding to the capacitor input time;
for a sampling point corresponding to the input moment of each capacitor, taking the polarity of the zero sequence voltage variation of a 10kV bus as a reference polarity, and comparing the polarity direction of the zero sequence current variation of each branch to be detected with the direction of the reference polarity; when the branch to be detected is a feeder line, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be correct, and if the direction of the zero sequence current variable quantity is opposite, the polarity of the zero sequence CT is judged to be reverse; when the branch to be detected is a bus capacitor, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be reverse, and if the direction is reverse, the polarity of the zero sequence CT is judged to be correct;
and determining a zero sequence CT polarity detection result corresponding to the input time period according to the obtained zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor.
According to a mode that can be realized by the first aspect of the present invention, the acquiring of the sampling data when the 10kV bus of the substation is put into the compensation capacitor bank includes:
and when the condition that the 10kV bus of the transformer substation is put into the compensation capacitor bank is detected, acquiring the sampling data.
According to an enabling aspect of the first aspect of the invention, the method further comprises:
and when the wavelet decomposition coefficient is constantly 0, outputting information for prompting that the compensation capacitor is put into the process at the moment to realize the synchronization.
According to one enabling aspect of the first aspect of the invention, the method comprises:
if the obtained wavelet decomposition coefficient satisfies the following formula, determining that the wavelet decomposition coefficient is constantly 0:
in the formula (I), the compound is shown in the specification,
is as follows
The number of wavelet decomposition coefficients is such that,
in order to obtain the number of wavelet decomposition coefficients,
in order to be a pre-set threshold value,
has a value range of
。
According to a manner that can be realized by the first aspect of the present invention, the determining a variation threshold according to each zero-sequence voltage variation includes:
calculating the variation threshold according to the following formula:
in the formula (I), the compound is shown in the specification,
a change amount threshold value is indicated, and,
in order to preset the adjustment coefficient,
is as follows
The zero sequence voltage variable quantity of the 10kV bus at the sampling point where the modulus maximum value is extracted in the second time,
the number of times of extraction of the modulus maximum of the wavelet coefficient.
According to an implementation manner of the first aspect of the present invention, determining a zero sequence CT polarity detection result corresponding to the commissioning time period according to the obtained zero sequence CT polarity determination result corresponding to the sampling point corresponding to the commissioning time of each capacitor includes:
and if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the input time of each capacitor are consistent, taking the zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of any capacitor as the zero sequence CT polarity detection result of the input time period.
According to an implementation manner of the first aspect of the present invention, determining a zero sequence CT polarity detection result corresponding to the input time period according to the obtained zero sequence CT polarity determination result corresponding to the sampling point corresponding to the input time of each capacitor further includes:
if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the capacitor input moments are inconsistent, performing the affiliated set scheduling on each zero sequence CT, specifically: determining a set to which the zero sequence CT currently belongs, wherein the set comprises a set A, a set B, a set C and a set D which are sequentially arranged from high to low according to the grade, and each zero sequence CT initially belongs to the set C; the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is classified into a set of the upper level, the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is not completely reserved in the original set, and the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity correct is classified into a set of the lower level;
and judging whether the current set A is an empty set, if not, determining the zero sequence CT in the current set A as the zero sequence CT with the reversed polarity, and outputting an alarm signal.
The second aspect of the present invention provides an online polarity detection system for zero-sequence CT, comprising:
the acquisition module is used for acquiring sampling data when the 10kV bus of the transformer substation is put into the compensation capacitor bank, wherein the sampling data comprises a zero-sequence voltage waveform of the 10kV bus corresponding to an input time period and a zero-sequence current waveform of each branch to be detected;
the wavelet decomposition module is used for selecting a db wavelet function to perform one-layer wavelet decomposition on the zero-sequence voltage waveform to obtain a corresponding wavelet decomposition coefficient;
the calculation module is used for decomposing and reconstructing a high-frequency band signal where a singular point of the zero-sequence voltage waveform is located when the wavelet decomposition coefficient is not constant to 0, extracting a modulus maximum value of a multi-time wavelet coefficient from the reconstructed signal waveform, and calculating the zero-sequence voltage variation of the 10kV bus and the zero-sequence current variation of each branch to be detected at the sampling point where each modulus maximum value is located;
the screening module is used for determining a variation threshold according to each zero-sequence voltage variation, and taking a sampling point where a corresponding module maximum value of which the zero-sequence voltage variation is greater than the variation threshold as a sampling point corresponding to the capacitor input time;
the zero sequence CT polarity judgment module is used for comparing the polarity direction of the zero sequence current variable quantity of each branch to be detected with the direction of the reference polarity by taking the polarity of the zero sequence voltage variable quantity of the 10kV bus as the reference polarity for the sampling point corresponding to the input moment of each capacitor; when the branch to be detected is a feeder line, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be correct, and if the direction of the zero sequence current variable quantity is opposite, the polarity of the zero sequence CT is judged to be reverse; when the branch to be detected is a bus capacitor, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be reverse, and if the direction is reverse, the polarity of the zero sequence CT is judged to be correct;
and the zero sequence CT polarity determining module is used for determining a zero sequence CT polarity detection result corresponding to the input time period according to the obtained zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor.
According to an implementable manner of the second aspect of the present invention, the obtaining module is specifically configured to:
and when the condition that the 10kV bus of the transformer substation is put into the compensation capacitor bank is detected, acquiring the sampling data.
According to an enabling manner of the second aspect of the invention, the system further comprises:
and the output module is used for outputting information for prompting that the compensation capacitor is put into the process at the moment to realize the synchronization when the wavelet decomposition coefficient is constantly 0.
According to an implementable manner of the second aspect of the present invention, the computing module is specifically configured to:
when the obtained wavelet decomposition coefficient satisfies the following formula, determining that the wavelet decomposition coefficient is constantly 0:
in the formula (I), the compound is shown in the specification,
is as follows
The number of wavelet decomposition coefficients is such that,
in order to obtain the number of wavelet decomposition coefficients,
in order to be a pre-set threshold value,
has a value range of
。
According to an implementation manner of the second aspect of the present invention, when the screening module determines the variation threshold according to each zero-sequence voltage variation, the screening module is specifically configured to:
calculating the variation threshold according to the following formula:
in the formula (I), the compound is shown in the specification,
a change amount threshold value is indicated, and,
in order to preset the adjustment coefficient,
is as follows
The zero sequence voltage variable quantity of the 10kV bus at the sampling point where the modulus maximum value is extracted in the second time,
the number of times of extraction of the modulus maximum of the wavelet coefficient.
According to an implementable manner of the second aspect of the present invention, the zero sequence CT polarity determination module is specifically configured to:
and if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the input time of each capacitor are consistent, taking the zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of any capacitor as the zero sequence CT polarity detection result of the input time period.
According to an implementable manner of the second aspect of the present invention, the zero sequence CT polarity determination module is further specifically configured to:
if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the capacitor input moments are inconsistent, performing the affiliated set scheduling on each zero sequence CT, specifically: determining a set to which the zero sequence CT currently belongs, wherein the set comprises a set A, a set B, a set C and a set D which are sequentially arranged from high to low according to the grade, and each zero sequence CT initially belongs to the set C; the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is classified into a set of the upper level, the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is not completely reserved in the original set, and the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity correct is classified into a set of the lower level;
and judging whether the current set A is an empty set, if not, determining the zero sequence CT in the current set A as the zero sequence CT with the reversed polarity, and outputting an alarm signal.
The third aspect of the present invention provides a zero sequence CT polarity online detection apparatus, including:
a memory to store instructions; the instruction is an instruction which can realize the zero sequence CT polarity online detection method in any one of the realizable modes;
a processor to execute the instructions in the memory.
A fourth aspect of the present invention is a computer-readable storage medium, which stores thereon a computer program, and when the computer program is executed by a processor, the zero sequence CT polarity online detection method as described in any one of the above-mentioned realizable manners is implemented.
According to the technical scheme, the invention has the following advantages:
the invention obtains the zero sequence voltage waveform of a 10kV bus and the zero sequence current waveform of each branch to be detected when the 10kV bus of a transformer substation is put into a compensation capacitor bank, processes the zero sequence voltage waveform through wavelet decomposition and signal reconstruction, extracts a modulus maximum value from the obtained signal waveform for multiple times, calculates the zero sequence voltage variation of the 10kV bus at the sampling point where the modulus maximum value is extracted and the zero sequence current variation of each branch to be detected, determines the sampling point corresponding to the putting time of the capacitor according to the calculated data, further takes the polarity of the zero sequence voltage variation as the reference polarity, judges the polarity direction of the zero sequence current variation corresponding to the sampling point corresponding to the putting time of each capacitor to be consistent with the direction of the corresponding reference polarity so as to determine whether the corresponding zero sequence CT polarity is reversed, and finally judges the result according to the zero sequence CT polarity corresponding to the sampling point corresponding to the putting time of each capacitor, determining a zero sequence CT polarity detection result of the current investment time period; the invention obtains sampling data based on the operation of a common 10kV bus switching capacitor bank, takes the zero sequence voltage polarity of the bus as a reference, compares the polarity with the zero sequence current polarity of each branch to be detected, and realizes the polarity judgment of each zero sequence CT.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a flowchart of a zero sequence CT polarity online detection method according to an alternative embodiment of the present invention;
FIG. 2 is a schematic diagram of a 10kV low resistance grounding system provided in an alternative embodiment of the present invention;
FIG. 3 is a diagram illustrating the result of wavelet decomposition according to an alternative embodiment of the present invention;
fig. 4 is a structural connection block diagram of a zero sequence CT polarity online detection system according to an optional embodiment of the present invention.
Reference numerals:
1-an acquisition module; 2-wavelet decomposition module; 3-a calculation module; 4-a screening module; 5-zero sequence CT polarity judgment module; and 6-zero sequence CT polarity determination module.
Detailed Description
The embodiment of the invention provides a zero sequence CT polarity online detection method, a zero sequence CT polarity online detection system and zero sequence CT polarity online detection equipment, which are used for solving the technical problems that the existing zero sequence CT polarity detection method has to judge the polarity of zero sequence CT when a ground fault occurs, and the defects of untimely judgment and large consumption of manpower and material resources exist.
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the embodiments described below 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.
The invention provides a zero sequence CT polarity online detection method.
Referring to fig. 1, fig. 1 shows a flowchart of a zero sequence CT polarity online detection method according to an embodiment of the present invention.
The zero sequence CT polarity online detection method provided by the embodiment of the invention comprises the steps of S1-S6.
And step S1, acquiring sampling data of the transformer substation 10kV bus when the transformer substation is put into the compensation capacitor bank, wherein the sampling data comprises zero-sequence voltage waveforms of the 10kV bus corresponding to the putting time period and zero-sequence current waveforms of the branches to be detected.
And when the condition that the 10kV bus of the transformer substation is put into the compensation capacitor bank is detected, acquiring the sampling data. According to the embodiment of the invention, when the 10kV bus of the transformer substation is put into the compensation capacitor bank, the wiring polarity distinguishing function of the zero sequence CT of each branch to be detected is started, so that the timeliness of the polarity detection of the zero sequence CT can be guaranteed.
Wherein the time span of the invested time period can be set according to actual conditions. In order to facilitate the subsequent wavelet decomposition and modulus maximum extraction operations, the input period at least includes 0.002s before the compensation capacitor bank is input to 0.004s after the compensation capacitor bank is input.
And step S2, selecting a db wavelet function to perform one-layer wavelet decomposition on the zero-sequence voltage waveform to obtain a corresponding wavelet decomposition coefficient.
Wherein the db wavelet function may be a db5 wavelet function, a db6 wavelet function, or a db7 wavelet function. In the embodiment, the zero-sequence voltage waveform is decomposed by the wavelet function, so that the advantages of wavelet analysis are achieved, and the advantages of wavelet analysis are expanded.
And step S3, when the wavelet decomposition coefficient is not constant 0, decomposing and reconstructing the high-frequency band signal where the singular point of the zero-sequence voltage waveform is located, extracting the modulus maximum of the wavelet coefficient for multiple times from the reconstructed signal waveform, and calculating the zero-sequence voltage variation of the 10kV bus and the zero-sequence current variation of each branch to be detected at the sampling point k where each modulus maximum is located.
After the module maximum value is extracted every time, the module maximum value, the sampling points corresponding to the module maximum value and the reconstructed zero sequence voltage values of the sampling points before and after the module maximum value are all set to be 0 so as to eliminate the influence of the module maximum value on the next extraction of the module maximum value.
The calculation formulas of the voltage variation and the current variation are respectively as follows:
in the formula (I), the compound is shown in the specification,
representing the sampling point corresponding to the modulus maximum
The zero sequence voltage variation of the 10kV bus,
as a sampling point
The zero sequence voltage of the 10kV bus at the place,
as a sampling point
Zero of 10kV busThe voltage of the sequence is changed according to the voltage,
indicating the sample point at which the modulus maximum lies
The zero sequence current variation of the branch to be detected,
as a sampling point
The zero sequence current variation of the branch to be detected,
as a sampling point
The zero sequence current variation of the branch to be detected.
The criterion that whether the wavelet decomposition coefficient is constant to 0 can be set as follows:
in the formula (I), the compound is shown in the specification,
is as follows
The number of wavelet decomposition coefficients is such that,
in order to obtain the number of wavelet decomposition coefficients,
in order to be a pre-set threshold value,
has a value range of
。
That is to say that the first and second electrodes,
and if so, judging that the obtained wavelet decomposition coefficient is constantly 0, otherwise, judging that the obtained wavelet decomposition coefficient is not constantly 0.
As a preference, the first and second liquid crystal compositions are,
take a value of
。
If the obtained wavelet decomposition coefficient is not constant to 0, the fact that the bus three-phase compensation capacitor is not simultaneously put into use is indicated, at the moment when the compensation capacitor is put into use, zero sequence voltage and zero sequence current fluctuation can be generated, and the polarity of the zero sequence current variable quantity of each feeder line and the 10kV side of the transformer is the same as that of the bus zero sequence voltage variable quantity and is opposite to that of the bus capacitor.
In one implementation, the method further comprises:
and when the wavelet decomposition coefficient is constantly 0, outputting information for prompting that the compensation capacitor is put into the process at the moment to realize the synchronization.
If the obtained wavelet decomposition coefficient is constant to 0, the simultaneous input of the bus three-phase compensation capacitor is realized, and at the moment, short-time zero-sequence current impact caused by the fact that the bus three-phase capacitors are not simultaneously input does not exist, so that the process of inputting the compensation capacitor bank cannot detect whether the polarity of the zero-sequence CT is reverse or not. According to the embodiment of the invention, when the wavelet decomposition coefficient is constantly 0, the judgment on the zero sequence CT wiring polarity is finished, the corresponding prompt information is output, the relevant substation maintainers can be reminded, and a data base is laid for the assessment of the operation stability of the substation and the like.
And step S4, determining a variation threshold value according to each zero-sequence voltage variation, and taking the sampling point of the corresponding module maximum value with the zero-sequence voltage variation larger than the variation threshold value as the sampling point corresponding to the capacitor input time.
Wherein the variation threshold may be calculated as follows:
in the formula (I), the compound is shown in the specification,
a change amount threshold value is indicated, and,
in order to preset the adjustment coefficient,
is as follows
The zero sequence voltage variable quantity of the 10kV bus at the sampling point where the modulus maximum value is extracted in the second time,
the number of times of extraction of the modulus maximum of the wavelet coefficient.
Step S5, regarding the sampling point corresponding to the input time of each capacitor, taking the polarity of the zero sequence voltage variation of the 10kV bus as the reference polarity, and comparing the polarity direction of the zero sequence current variation of each branch to be detected with the direction of the reference polarity; when the branch to be detected is a feeder line, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be correct, and if the direction of the zero sequence current variable quantity is opposite, the polarity of the zero sequence CT is judged to be reverse; when the branch to be detected is a bus capacitor, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be reverse, and if the direction is reverse, the polarity of the zero sequence CT is judged to be correct.
When a three-phase compensation capacitor is put into a primary bus, because the three-phase capacitors are not completely the same in the moment of putting, multiple zero sequence impacts can be generated. According to the embodiment of the invention, sampling points corresponding to the charging transient time of the compensation capacitors are extracted in the process of putting the three-phase compensation capacitor into the primary bus, and the polarity of the zero-sequence CT is judged for multiple times, so that the accuracy of the judgment result is improved.
In step S5, the principle of determining the polarity of the zero-order CT is:
analyzing the transient process of firstly putting the capacitor into the phase A of the 10kV bus of the transformer substation which is in symmetrical and stable operation of the original three phases, it can be obtained that at the moment of putting the compensation capacitor into the phase A, the polarity of the zero-sequence current variable quantity of the feeder line (transmission line) and the 10kV side of the transformer and the zero-sequence voltage of the bus can be obtained
The polarity of the variable quantity is the same and is opposite to the polarity of the variable quantity of the zero sequence current of the bus capacitor;
when the A phase of the 10kV bus of the transformer substation is put into the capacitor and is stabilized, analyzing the transient process of putting into the capacitor in the B phase to obtain that at the moment when the B phase compensation capacitor is put into the capacitor, the polarity of the zero sequence current variable quantity of the feeder line (power transmission line) and the 10kV side of the transformer is the same as the polarity of the zero sequence voltage variable quantity of the bus and is opposite to the polarity of the zero sequence current variable quantity of the bus capacitor;
in summary, no matter whether the power grid bus compensation capacitor is originally in a parameter symmetric state, as long as the bus three-phase compensation capacitor is not simultaneously and instantaneously put in, zero sequence voltage and zero sequence current fluctuation can be generated at the moment when the compensation capacitor is put in, and the polarity of the zero sequence current variation of each feeder line and the 10kV side of the transformer is the same as the polarity of the bus zero sequence voltage variation and is opposite to the polarity of the zero sequence current variation of the bus capacitor, so that whether the zero sequence CT connection polarity of each branch to be detected is reversed can be judged according to the polarity.
And step S6, determining a zero sequence CT polarity detection result corresponding to the input time period according to the obtained zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor.
When step S6 is executed, it is necessary to determine whether the zero sequence CT polarity determination results corresponding to the sampling points corresponding to the capacitor input time are consistent. And if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the input time of each capacitor are consistent, taking the zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of any capacitor as the zero sequence CT polarity detection result of the input time period, and directly outputting the zero sequence CT polarity detection result.
If the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the capacitor input time are inconsistent, the polarity detection result of each zero sequence CT needs to be further determined according to the polarity judgment result of each zero sequence CT, so as to improve the polarity judgment precision.
In specific implementation, 4 sets may be preset, and the 4 sets are sequentially arranged in order from high to low according to the rank, as a set a, a set B, a set C, and a set D, where the set a is a zero-sequence CT set with reversed polarity, the set B is a zero-sequence CT set with reversed probability, the set C is a zero-sequence CT set with reversed possibility, and the set D is a zero-sequence CT set with correct polarity. Initially, each zero sequence CT belongs to set C.
For a zero sequence CT, if the polarity of the zero sequence CT is judged to be reversed in the polarity judgment result of each zero sequence CT, the zero sequence CT is classified into a set of the previous level; if the polarity of the zero-sequence CT is not completely judged to be reversed in polarity in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is kept in the original set; and if the polarity of the zero-sequence CT is judged to be correct in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is classified into a set of the next grade.
For example, a zero sequence CT currently belongs to set C; if the polarity of the zero-sequence CT is judged to be reversed in polarity in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is classified into a set B; if the polarity of the zero-sequence CT is not completely judged to be reversed in polarity in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is reserved in a set C; and if the polarity of the zero-sequence CT is judged to be correct in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is classified into a set D.
For another example, a zero sequence CT currently belongs to set B; if the polarity of the zero-sequence CT is judged to be reversed in polarity in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is classified into a set A; if the polarity of the zero-sequence CT is not completely judged to be reversed in polarity in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is reserved in a set B; and if the polarity of the zero-sequence CT is judged to be correct in the polarity judgment result of each zero-sequence CT, the zero-sequence CT is classified into the set C.
If the polarity of each zero-sequence CT in the polarity determination result of each zero-sequence CT is determined to be correct, the zero-sequence CT is not degraded and remains in the set D. If a zero sequence CT currently belongs to the set a, if the polarity of the zero sequence CT in the polarity judgment result of each zero sequence CT is judged to be reversed, the zero sequence CT is not upgraded, and is still kept in the set a.
And further, judging whether the current set A is an empty set, if not, determining the zero sequence CT in the current set A as the zero sequence CT with the reverse polarity, and outputting an alarm signal, otherwise, determining the polarity of the zero sequence CT by combining the judgment result of the polarity of the zero sequence CT when the next bus is put into the three-phase compensation capacitor.
Due to the limitation of the sampling frequency of zero sequence protection, the zero sequence current of the feeder line at the moment when a certain capacitor is put into the three-phase compensation capacitor is not correctly collected, so that the judgment result at the moment when the certain capacitor is put into the three-phase compensation capacitor is wrong.
To more clearly illustrate the method of the above-described embodiments of the present invention, a detailed description is provided below.
Fig. 2 shows a schematic diagram of a 10kV low resistance grounding system of an embodiment of the present invention. In fig. 2, the 10kV small-resistance grounding system includes six feeders, which are Line1, Line2, Line3, Line4, Line5 and Line6, respectively, wherein the zero-sequence CT polarities of the feeders Line2, Line3 and Line5 are reversed. Wherein arrows below I1, I2, I3, I4, I5 and I6 respectively indicate the polarity direction of the corresponding feeder line, Tline-5km indicates an overhead line 5km, Tline-8km indicates an overhead line 8km, and Dline-8km indicates a cable line 8 km.
When the zero sequence CT detection is carried out on the 10kV small-resistance grounding system, the detection method comprises the following steps:
step one, when a bus in a 10kV small-resistance grounding system shown in fig. 2 is prepared to be put into a compensation capacitor, starting a wiring polarity distinguishing function of a zero sequence CT of each branch to be detected, wherein the preset time for putting into the capacitor bank is 0.203s, the actual time for putting into a three-phase capacitor caused by errors of putting into a switch and the like is 0.202763s, 0.203846s and 0.202653s respectively, acquiring zero sequence voltage waveforms of the 10kV bus and zero sequence current waveforms of each branch to be detected within a certain time (at least including 0.002s before putting into the capacitor to 0.004s after putting into the capacitor), and acquiring the frequency of the zero sequence voltage waveforms of the 10kV bus and the zero sequence current waveforms of each branch to be detected, wherein the acquisition frequency is 4 kHz;
selecting a db5 wavelet function to perform one-layer wavelet decomposition on the collected zero sequence voltage of the 10kV bus, wherein the wavelet decomposition result is shown in FIG. 3;
wherein, the abscissa in the graph entitled "low frequency coefficient" and "high frequency coefficient" in fig. 3 is the number of sampling points (dimensionless), and the ordinate is the wavelet coefficient (dimensionless);
step three, executing the criterion to obtain:
if the obtained wavelet decomposition coefficient is not constant to 0, the bus three-phase compensation capacitor is not input at the same time, and the step four is executed;
decomposing and reconstructing a high-frequency band signal where a singular point of the zero-sequence voltage waveform is located, extracting a modulus maximum value of a cubic wavelet coefficient from the reconstructed signal waveform, and setting the reconstructed zero-sequence voltage values of a sampling point corresponding to the modulus maximum value and a sampling point before and after the sampling point to be 0 after the modulus maximum value is extracted each time so as to eliminate the influence of the modulus maximum value on the next extraction of the modulus maximum value;
step five, calculating the zero sequence voltage variation of the 10kV bus at the sampling point where the extracted module maximum value is located and the zero sequence current variation of each branch to be detected, and screening out different input time points of the three-phase capacitor extracted by mistake, wherein the criterion is as follows:
in the formula (I), the compound is shown in the specification,
is as follows
Extracting the zero sequence voltage variable quantity of the 10kV bus at the sampling point where the modulus maximum value is located in the secondary extraction;
sampling points corresponding to the screened three-phase capacitor input time are 0.202750s and 0.203750 s;
step six, at different input time points of the determined three-phase capacitor, taking the polarity of the zero-sequence voltage variation of the 10kV bus as a reference polarity, and comparing the polarity of the zero-sequence current variation of each branch to be detected with the reference polarity direction: if the polarity of the feeder line is consistent with the direction of the reference polarity, judging that the polarity of the zero-sequence CT is correct, and if the polarity of the feeder line is opposite to the direction of the reference polarity, judging that the polarity of the zero-sequence CT is reverse; if the polarity of the bus capacitor is opposite to the reference polarity, the polarity of the zero-sequence CT is judged to be correct, and if the polarity of the zero-sequence CT is consistent, the polarity of the zero-sequence CT is judged to be reverse.
The results of this example are shown in Table 1:
TABLE 1
As can be seen from table 1, the zero sequence CT determination results corresponding to the sampling points corresponding to the two three-phase capacitors at the time of the input are consistent, and at this time, the zero sequence CT determination results are directly output.
The invention also provides a zero sequence CT polarity online detection system.
Referring to fig. 4, fig. 4 is a structural connection block diagram of a zero sequence CT polarity online detection system according to an embodiment of the present invention.
The zero sequence CT polarity online detection system provided by the embodiment of the invention comprises:
the acquisition module 1 is used for acquiring sampling data when a 10kV bus of a transformer substation is put into a compensation capacitor bank, wherein the sampling data comprises a zero-sequence voltage waveform of the 10kV bus corresponding to an input time period and a zero-sequence current waveform of each branch to be detected;
the wavelet decomposition module 2 is used for selecting a db wavelet function to perform one-layer wavelet decomposition on the zero sequence voltage waveform to obtain a corresponding wavelet decomposition coefficient;
the calculation module 3 is configured to decompose and reconstruct a high-frequency band signal in which a singular point of the zero-sequence voltage waveform is located when the wavelet decomposition coefficient is not constant 0, extract a modulus maximum of a multiple wavelet coefficient from the reconstructed signal waveform, and calculate a zero-sequence voltage variation of the 10kV bus and a zero-sequence current variation of each to-be-detected branch at a sampling point in which each modulus maximum is located;
the screening module 4 is used for determining a variation threshold according to each zero-sequence voltage variation, and taking a sampling point where a corresponding module maximum value of the zero-sequence voltage variation which is greater than the variation threshold is located as a sampling point corresponding to the capacitor input time;
the zero sequence CT polarity judgment module 5 is used for comparing the polarity direction of the zero sequence current variable quantity of each branch to be detected with the direction of the reference polarity by taking the polarity of the zero sequence voltage variable quantity of the 10kV bus as the reference polarity for the sampling point corresponding to the input time of each capacitor; when the branch to be detected is a feeder line, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be correct, and if the direction of the zero sequence current variable quantity is opposite, the polarity of the zero sequence CT is judged to be reverse; when the branch to be detected is a bus capacitor, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be reverse, and if the direction is reverse, the polarity of the zero sequence CT is judged to be correct;
and the zero sequence CT polarity determining module 6 is used for determining a zero sequence CT polarity detection result corresponding to the input time period according to the obtained zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor.
In an implementation manner, the obtaining module 1 is specifically configured to:
and when the condition that the 10kV bus of the transformer substation is put into the compensation capacitor bank is detected, acquiring the sampling data.
In one implementation, the system further comprises:
and the output module is used for outputting information for prompting that the compensation capacitor is put into the process at the moment to realize the synchronization when the wavelet decomposition coefficient is constantly 0.
In an implementation manner, the computing module 3 is specifically configured to:
when the obtained wavelet decomposition coefficient satisfies the following formula, determining that the wavelet decomposition coefficient is constantly 0:
in the formula (I), the compound is shown in the specification,
is as follows
The number of wavelet decomposition coefficients is such that,
in order to obtain the number of wavelet decomposition coefficients,
in order to be a pre-set threshold value,
has a value range of
。
In an implementation manner, when the screening module 4 determines the variation threshold according to each zero-sequence voltage variation, it is specifically configured to:
calculating the variation threshold according to the following formula:
in the formula (I), the compound is shown in the specification,
a change amount threshold value is indicated, and,
in order to preset the adjustment coefficient,
is as follows
The zero sequence voltage variable quantity of the 10kV bus at the sampling point where the modulus maximum value is extracted in the second time,
the number of times of extraction of the modulus maximum of the wavelet coefficient.
In an implementation manner, the zero sequence CT polarity determining module 6 is specifically configured to:
and if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the input time of each capacitor are consistent, taking the zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of any capacitor as the zero sequence CT polarity detection result of the input time period.
In an implementation manner, the zero sequence CT polarity determining module 6 is further specifically configured to:
if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the capacitor input moments are inconsistent, performing the affiliated set scheduling on each zero sequence CT, specifically: determining a set to which the zero sequence CT currently belongs, wherein the set comprises a set A, a set B, a set C and a set D which are sequentially arranged from high to low according to the grade, and each zero sequence CT initially belongs to the set C; the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is classified into a set of the upper level, the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is not completely reserved in the original set, and the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity correct is classified into a set of the lower level;
and judging whether the current set A is an empty set, if not, determining the zero sequence CT in the current set A as the zero sequence CT with the reversed polarity, and outputting an alarm signal.
The invention also provides a zero sequence CT polarity online detection device, which comprises:
a memory to store instructions; the instruction is an instruction which can implement the zero sequence CT polarity online detection method according to any one of the above embodiments;
a processor to execute the instructions in the memory.
The invention further provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and when being executed by a processor, the computer program implements the zero sequence CT polarity online detection method according to any one of the above embodiments.
In the embodiment of the invention, the 10kV bus switching capacitor bank belongs to common operation, zero sequence current generated in the grounding short circuit is not used for judging the polarity of the zero sequence CT, the polarity reverse error of the zero sequence CT connection can be judged more timely, the correct action of zero sequence protection when the power grid fails is facilitated, and the safe and stable operation of the power grid is ensured.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes and effects of the above-described systems, devices and modules may refer to the corresponding processes and effects in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the modules is merely a logical division, and other divisions may be realized in practice, for example, a plurality of modules or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or modules, and may be in an electrical, mechanical or other form.
The modules described as separate parts may or may not be physically separate, and parts displayed as modules may or may not be physical modules, may be located in one place, or may be distributed on a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
In addition, functional modules in the embodiments of the present invention may be integrated into one processing module, or each of the modules may exist alone physically, or two or more modules are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode.
The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A zero sequence CT polarity online detection method is characterized by comprising the following steps:
acquiring sampling data when a 10kV bus of a transformer substation is put into a compensation capacitor bank, wherein the sampling data comprises zero-sequence voltage waveforms of the 10kV bus corresponding to an input time period and zero-sequence current waveforms of all branches to be detected;
selecting a db wavelet function to perform one-layer wavelet decomposition on the zero sequence voltage waveform to obtain a corresponding wavelet decomposition coefficient;
when the wavelet decomposition coefficient is not constant to 0, decomposing and reconstructing a high-frequency band signal where a singular point of the zero-sequence voltage waveform is located, extracting a modulus maximum value of a multi-time wavelet coefficient from the reconstructed signal waveform, and calculating the zero-sequence voltage variation of the 10kV bus and the zero-sequence current variation of each branch to be detected at the sampling point where each modulus maximum value is located;
determining a variation threshold value according to each zero-sequence voltage variation, and taking a sampling point where a corresponding module maximum value of the zero-sequence voltage variation which is greater than the variation threshold value is located as a sampling point corresponding to the capacitor input time;
for a sampling point corresponding to the input moment of each capacitor, taking the polarity of the zero sequence voltage variation of a 10kV bus as a reference polarity, and comparing the polarity direction of the zero sequence current variation of each branch to be detected with the direction of the reference polarity; when the branch to be detected is a feeder line, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be correct, and if the direction of the zero sequence current variable quantity is opposite, the polarity of the zero sequence CT is judged to be reverse; when the branch to be detected is a bus capacitor, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be reverse, and if the direction is reverse, the polarity of the zero sequence CT is judged to be correct;
and determining a zero sequence CT polarity detection result corresponding to the input time period according to the obtained zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor.
2. The zero sequence CT polarity online detection method of claim 1, wherein the obtaining of sampling data when a 10kV bus of a transformer substation is thrown into a compensation capacitor bank comprises:
and when the condition that the 10kV bus of the transformer substation is put into the compensation capacitor bank is detected, acquiring the sampling data.
3. The zero sequence CT polarity online detection method according to claim 1, further comprising:
and when the wavelet decomposition coefficient is constantly 0, outputting information for prompting that the compensation capacitor is put into the process at the moment to realize the synchronization.
4. The zero sequence CT polarity online detection method according to claim 3, characterized by comprising the following steps:
if the obtained wavelet decomposition coefficient satisfies the following formula, determining that the wavelet decomposition coefficient is constantly 0:
in the formula (I), the compound is shown in the specification,
is as follows
The number of wavelet decomposition coefficients is such that,
in order to obtain the number of wavelet decomposition coefficients,
in order to be a pre-set threshold value,
has a value range of
。
5. The zero-sequence CT polarity online detection method according to claim 1, wherein the determining a variation threshold according to each zero-sequence voltage variation includes:
calculating the variation threshold according to the following formula:
in the formula (I), the compound is shown in the specification,
a change amount threshold value is indicated, and,
in order to preset the adjustment coefficient,
is as follows
The zero sequence voltage variable quantity of the 10kV bus at the sampling point where the modulus maximum value is extracted in the second time,
the number of times of extraction of the modulus maximum of the wavelet coefficient.
6. The zero-sequence CT polarity online detection method according to claim 1, wherein determining the zero-sequence CT polarity detection result corresponding to the input time period according to the obtained zero-sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor comprises:
and if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the input time of each capacitor are consistent, taking the zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of any capacitor as the zero sequence CT polarity detection result of the input time period.
7. The zero-sequence CT polarity online detection method according to claim 6, wherein the determining the zero-sequence CT polarity detection result corresponding to the input time period according to the obtained zero-sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor further comprises:
if the zero sequence CT polarity judgment results corresponding to the sampling points corresponding to the capacitor input moments are inconsistent, performing the affiliated set scheduling on each zero sequence CT, specifically: determining a set to which the zero sequence CT currently belongs, wherein the set comprises a set A, a set B, a set C and a set D which are sequentially arranged from high to low according to the grade, and each zero sequence CT initially belongs to the set C; the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is classified into a set of the upper level, the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity reversed is not completely reserved in the original set, and the zero sequence CT with the polarity judgment results of all the zero sequence CT with the polarity correct is classified into a set of the lower level;
and judging whether the current set A is an empty set, if not, determining the zero sequence CT in the current set A as the zero sequence CT with the reversed polarity, and outputting an alarm signal.
8. The zero sequence CT polarity online detection system is characterized by comprising:
the acquisition module is used for acquiring sampling data when the 10kV bus of the transformer substation is put into the compensation capacitor bank, wherein the sampling data comprises a zero-sequence voltage waveform of the 10kV bus corresponding to an input time period and a zero-sequence current waveform of each branch to be detected;
the wavelet decomposition module is used for selecting a db wavelet function to perform one-layer wavelet decomposition on the zero-sequence voltage waveform to obtain a corresponding wavelet decomposition coefficient;
the calculation module is used for decomposing and reconstructing a high-frequency band signal where a singular point of the zero-sequence voltage waveform is located when the wavelet decomposition coefficient is not constant to 0, extracting a modulus maximum value of a multi-time wavelet coefficient from the reconstructed signal waveform, and calculating the zero-sequence voltage variation of the 10kV bus and the zero-sequence current variation of each branch to be detected at the sampling point where each modulus maximum value is located;
the screening module is used for determining a variation threshold according to each zero-sequence voltage variation, and taking a sampling point where a corresponding module maximum value of which the zero-sequence voltage variation is greater than the variation threshold as a sampling point corresponding to the capacitor input time;
the zero sequence CT polarity judgment module is used for comparing the polarity direction of the zero sequence current variable quantity of each branch to be detected with the direction of the reference polarity by taking the polarity of the zero sequence voltage variable quantity of the 10kV bus as the reference polarity for the sampling point corresponding to the input moment of each capacitor; when the branch to be detected is a feeder line, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be correct, and if the direction of the zero sequence current variable quantity is opposite, the polarity of the zero sequence CT is judged to be reverse; when the branch to be detected is a bus capacitor, if the polarity direction of the zero sequence current variable quantity of the branch to be detected is consistent with the direction of the reference polarity, the polarity of the zero sequence CT is judged to be reverse, and if the direction is reverse, the polarity of the zero sequence CT is judged to be correct;
and the zero sequence CT polarity determining module is used for determining a zero sequence CT polarity detection result corresponding to the input time period according to the obtained zero sequence CT polarity judgment result corresponding to the sampling point corresponding to the input time of each capacitor.
9. The utility model provides a zero sequence CT polarity on-line measuring equipment which characterized in that includes:
a memory to store instructions; wherein, the instruction is an instruction for implementing the zero sequence CT polarity online detection method according to any one of claims 1 to 7;
a processor to execute the instructions in the memory.
10. A computer-readable storage medium, wherein the computer-readable storage medium stores thereon a computer program, and when the computer program is executed by a processor, the zero sequence CT polarity online detection method according to any one of claims 1 to 7 is implemented.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210139618.0A CN114200354B (en) | 2022-02-16 | 2022-02-16 | Zero sequence CT polarity online detection method, system and equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210139618.0A CN114200354B (en) | 2022-02-16 | 2022-02-16 | Zero sequence CT polarity online detection method, system and equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114200354A CN114200354A (en) | 2022-03-18 |
| CN114200354B true CN114200354B (en) | 2022-04-19 |
Family
ID=80658960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210139618.0A Active CN114200354B (en) | 2022-02-16 | 2022-02-16 | Zero sequence CT polarity online detection method, system and equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114200354B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116520197B (en) * | 2023-07-05 | 2023-08-25 | 广东电网有限责任公司肇庆供电局 | Low-voltage transformer area circuit detection method and system |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108196214A (en) * | 2017-12-12 | 2018-06-22 | 神华集团有限责任公司 | Feeder line zero sequence current mutual inductor CT polarity check methods and device |
| CN109061376A (en) * | 2018-09-19 | 2018-12-21 | 上海蓝瑞电气有限公司 | A kind of judgment method of Small Electric Current Earthing And Routing Device CT incorrect polarity |
| CN109980614A (en) * | 2019-03-29 | 2019-07-05 | 广东电网有限责任公司 | A kind of distribution line zero-sequenceprotection direction-adaptive method of discrimination |
| CN110907758A (en) * | 2019-12-06 | 2020-03-24 | 国电南瑞科技股份有限公司 | Small current ground fault line selection method covering CT polarity self-correction |
| CN110927631A (en) * | 2019-12-03 | 2020-03-27 | 陕西省地方电力（集团）有限公司宝鸡供电分公司 | Polarity judgment method for zero-sequence current transformer |
| CN111308398A (en) * | 2020-03-31 | 2020-06-19 | 深圳供电局有限公司 | Method and device for judging polarity of zero sequence current transformer in transformer substation |
| CN111398871A (en) * | 2020-04-07 | 2020-07-10 | 国家电网有限公司 | Device and method for checking polarity of zero sequence current transformer |
| CN111812452A (en) * | 2020-06-11 | 2020-10-23 | 国电南瑞科技股份有限公司 | CT polarity self-correction method and system for low-current grounding line selection device |
| CN112083372A (en) * | 2020-08-21 | 2020-12-15 | 深圳供电局有限公司 | Current transformer polarity identification method and system |
| CN112290516A (en) * | 2020-10-10 | 2021-01-29 | 威胜信息技术股份有限公司 | Overvoltage protection system, method and device based on bus and outgoing line polarity characteristics |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10191102B2 (en) * | 2015-01-27 | 2019-01-29 | Utility Relay Company | Automatic current transformer polarity correction |
-
2022
- 2022-02-16 CN CN202210139618.0A patent/CN114200354B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108196214A (en) * | 2017-12-12 | 2018-06-22 | 神华集团有限责任公司 | Feeder line zero sequence current mutual inductor CT polarity check methods and device |
| CN109061376A (en) * | 2018-09-19 | 2018-12-21 | 上海蓝瑞电气有限公司 | A kind of judgment method of Small Electric Current Earthing And Routing Device CT incorrect polarity |
| CN109980614A (en) * | 2019-03-29 | 2019-07-05 | 广东电网有限责任公司 | A kind of distribution line zero-sequenceprotection direction-adaptive method of discrimination |
| CN110927631A (en) * | 2019-12-03 | 2020-03-27 | 陕西省地方电力（集团）有限公司宝鸡供电分公司 | Polarity judgment method for zero-sequence current transformer |
| CN110907758A (en) * | 2019-12-06 | 2020-03-24 | 国电南瑞科技股份有限公司 | Small current ground fault line selection method covering CT polarity self-correction |
| CN111308398A (en) * | 2020-03-31 | 2020-06-19 | 深圳供电局有限公司 | Method and device for judging polarity of zero sequence current transformer in transformer substation |
| CN111398871A (en) * | 2020-04-07 | 2020-07-10 | 国家电网有限公司 | Device and method for checking polarity of zero sequence current transformer |
| CN111812452A (en) * | 2020-06-11 | 2020-10-23 | 国电南瑞科技股份有限公司 | CT polarity self-correction method and system for low-current grounding line selection device |
| CN112083372A (en) * | 2020-08-21 | 2020-12-15 | 深圳供电局有限公司 | Current transformer polarity identification method and system |
| CN112290516A (en) * | 2020-10-10 | 2021-01-29 | 威胜信息技术股份有限公司 | Overvoltage protection system, method and device based on bus and outgoing line polarity characteristics |
Non-Patent Citations (5)
| Title |
|---|
| 中性点不接地系统零序功率方向保护极性判定及试验方法;刘玉春;《工程技术研究》;20180923(第10期);第41-46页 * |
| 利用单端暂态量检测单相高阻接地故障的新方法;陈佳佳 等;《电力系统自动化》;20070510;第31卷(第9期);第56-60、86页 * |
| 带负荷检查零序功率方向继电器的正确性;刘义;《内蒙古电力技术》;19940828(第04期);第74-75页 * |
| 浅析保护零序电流互感器带电检测方法;陈娟等;《通讯世界》;20150625(第12期);第126-127页 * |
| 零序电流互感器一致性和极性的带电检测方法研究;李长明;《中国优秀博硕士学位论文全文数据库(硕士)工程科技Ⅱ辑》;20130315(第3期);第C042-250页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114200354A (en) | 2022-03-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3043186B1 (en) | Method and system for identifying full parameters of element by fault recorder, and fault locating method | |
| CN110441641A (en) | A kind of small current earthing wire-selecting method and system based on Zero sequence DC component | |
| CN113391164A (en) | Intelligent identification method and device for single-phase earth fault of power distribution network | |
| CN104375025A (en) | Diagnostic method for ferromagnetic resonance in neutral non-grounding 10kV system | |
| CN103869184A (en) | PMU data-based identification method for single electric transmission line zero-sequence parameter robustness | |
| CN114200354B (en) | Zero sequence CT polarity online detection method, system and equipment | |
| CN110174585B (en) | Method for identifying open circuit fault of high-voltage capacitor of double-tuned alternating current filter | |
| CN113533910A (en) | Method and system suitable for converter transformer partial discharge early warning | |
| CN107797023B (en) | Three-phase voltage unbalance source positioning method, device and system | |
| CN107238780B (en) | The compensation of ground power grid self-adaption route selection method classified using Rough Set | |
| CN107909035A (en) | A kind of reading of quasi real time failure wave-recording file and analysis system | |
| CN103823158A (en) | Resonant earthed system fault line selection method with invariant moments | |
| CN105701265B (en) | A kind of double-fed fan motor unit modeling method and device | |
| CN117148212A (en) | Single-phase earth fault line selection method for small-current grounding system of micro-grid power distribution network | |
| CN113740791A (en) | Distribution network fault indicator wave recording accuracy testing method and system | |
| CN113419139B (en) | High-resistance grounding fault positioning method and related device for small-resistance grounding system | |
| CN115954956A (en) | Method and system for evaluating access capacity of distributed power supply of power distribution network | |
| CN110988590B (en) | PCA-SVM model-based distribution network line selection method and system | |
| CN105896525B (en) | Power grid large disturbances recognition methods based on WAMS | |
| CN111737875B (en) | Active power unbalance rate analysis and diagnosis method, system and computer equipment | |
| CN109038683B (en) | Method, device and equipment for evaluating accuracy of primary frequency modulation frequency signal source | |
| CN109088413B (en) | Dynamic reactive power planning and site selection method and device for direct-current receiving-end power grid | |
| CN112485523A (en) | Method for judging harmonic voltage measurement distortion | |
| CN106443352A (en) | Method for single-phase earth fault line selection of neutral non-grounding power grid | |
| CN110873832A (en) | Power distribution network line selection method and system based on wavelet energy entropy |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |