CN113589212B - Method for determining saturation point of current transformer based on maximum offset method - Google Patents
Method for determining saturation point of current transformer based on maximum offset method Download PDFInfo
- Publication number
- CN113589212B CN113589212B CN202110716000.1A CN202110716000A CN113589212B CN 113589212 B CN113589212 B CN 113589212B CN 202110716000 A CN202110716000 A CN 202110716000A CN 113589212 B CN113589212 B CN 113589212B
- Authority
- CN
- China
- Prior art keywords
- max
- point
- current
- voltage
- saturation
- 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
- 238000000034 method Methods 0.000 title claims abstract description 36
- 238000005070 sampling Methods 0.000 claims abstract description 62
- 230000007704 transition Effects 0.000 claims description 7
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- 230000001419 dependent effect Effects 0.000 claims description 4
- 229920006395 saturated elastomer Polymers 0.000 claims description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- 230000009466 transformation Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- 238000011179 visual inspection Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012806 monitoring device Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 208000001491 myopia Diseases 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000004832 voltammetry Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention provides a method for determining a saturation point of a current transformer based on a maximum offset method, which comprises the steps of sampling from an O point to a C point on a current-voltage characteristic curve OC of a secondary coil at equal intervals, and calculating the vertical line distance from each sampling point to an average current-voltage relation straight line, namely offset, wherein the sampling point with the maximum offset is the saturation point; the method can be directly used in a program of an intelligent instrument, equidistant sampling is carried out on a current-voltage characteristic curve OC of the secondary coil obtained in practice, and the position of a saturation point H is determined by the maximum offset, in theory, the more the number of sampling points is, the more accurate the position of the saturation point H is; in actual work, the number of sampling points can be determined according to the precision requirement, the position of the saturation point H of the current transformer can be accurately determined, the actually measured position of the saturation point H of the current transformer can be compared with the factory position, whether the current transformer is aged or damaged is judged, and the method has very important guiding significance for the work of the power industry.
Description
Technical Field
The invention relates to the technical field of current transformers, in particular to a method for determining a saturation point of a current transformer based on a maximum offset method.
Background
At present, the current transformer used in the power industry of China is mainly electromagnetic, and the working principle of the current transformer is the same as that of a transformer, namely, two coils are sleeved on the same iron core, the first coil is defined as a primary coil, the primary coil is connected in a working loop of a circuit, and the current flowing in the primary coil is defined as primary current; the second coil is defined as a secondary coil for taking a primary current, called secondary current, at a certain transformation ratio, which is used to drive a meter or provided to an automated monitoring device for monitoring or protecting the power components (transformers, generators, etc.).
Normally, the primary current is within the rated current range, and there is a fixed proportional relationship between the current value in the secondary coil of the current transformer and the current value in the primary coil, and this fixed proportion is defined as the transformation ratio of the current transformer, for example: the transformation ratio is 600:5, namely the primary rated current of the current transformer is 600A, and the secondary rated current is 5A; when 600A current flows through the primary coil of the current transformer, 5A An Dianliu flows through the secondary coil; when the primary coil of the current transformer flows 300A current, the secondary coil flows 2.5A current; when the primary coil of the current transformer flows through 60A current, the secondary coil flows through 0.5A current; analogize, maintenance of primary and secondary currents 600:5 is unchanged, and the following formula is shown:
wherein I1 represents the current value flowing through the primary coil of the current transformer, and I2 represents the current value flowing through the secondary coil of the current transformer;
further, another technical parameter of the current transformer is precision, which is expressed by a 'level'; the current transformers of the 0.2 level, the 0.5 level and the 1.0 level respectively show that the error of the current transformer is not more than 0.2 percent, 0.5 percent and 1.0 percent within the rated current;
there is also a problem with overload bit multiples for Protection current transformers, such as 5P10, where the letter P indicates the Protection transformer, and the number following P indicates 10, indicating that one is allowedSecondary timesThe current is overloaded 10 times in the accident state, and 5 before P indicates that the current flows at one timeUnder the condition of 10 times load, the current transformer can still ensure the precision to be not lower than 5 percent.
The transformation ratio is an important technical index of the current transformer, and when the primary current exceeds a rated value, the proportional relation between the primary current and the secondary current is not maintained to be constant, but is deviated from the constant. The more the primary current exceeds the rated current, the more the ratio of primary current to secondary current deviates from the transformation ratio, a phenomenon known as saturation of the current transformer.
After the saturation of the current transformer, when the primary current is increased again, the secondary current is not increased obviously, and obviously, the primary current cannot be represented in proportion accurately after the saturation.
The saturation phenomenon of the current transformer is mainly applied to the power engineering technology in the following two cases:
first case: in order to prevent secondary equipment from being burnt out, a current transformer easy to saturate is selected, and the method specifically comprises the following steps:
if the rated current is 10A, the maximum working current is 50A, the short-circuit current is 500A, and the ratio of the current meter (full-grid index is 10A) is 50:5, the current transformer ensures that the ammeter can reflect the working current of the circuit when the circuit is normal; secondly, selecting a saturation point, if a current transformer with a saturation current of 50A is selected, when the equipment is short-circuited, the primary current of the current transformer reaches 500A, but the proportional transfer of the short-circuit current of more than 50A to the secondary current is restrained due to the saturation effect, the current flowing through the ammeter is only 5.9A, and is not 50A calculated according to the transformation ratio. If a current transformer with the saturation current of 500A is selected, when the equipment is short-circuited, the primary short-circuit current is all 50: the 5 ratio is transferred to the ammeter loop, and the ammeter can be burnt out immediately when the ammeter reaches 50A.
Second case: the current transformer matched with the protection device is used, so that the protection device accurately senses the abnormal working state of the primary circuit, and the current transformer which is not easy to saturate is selected, and the current transformer is specifically:
in order to facilitate understanding of the person skilled in the art, taking the electric equipment condition of the first condition (an ammeter with rated current of 10A, to measure the maximum working current to 50A and short-circuit current to 500A electric equipment) as an example, a current protection device with rated current of 5A and allowing 10 times (namely 50A) of instantaneous overload of faults is provided, and the protection set value is set to 20A, namely tripping and power-off are performed when the primary equipment current is greater than 200A; if the front end of the protection device is matched with a current transformer with the saturation current of 50A which is still the first condition, when electric equipment has a short circuit fault, the short current actually reaches 500A, but the current transmitted to the protection device is only 5.9A actually due to the saturation effect of the current transformer, which is far lower than 20A set by a protection fixed value, so that the protection device can not act and the fault can not be cut off correctly; for the same transformation ratio, if the 10P10 current transformer with the saturation point of 500A is used first, the current transmitted to the protection device can reach 49A to 50A, and is larger than the set trip constant value 20A, and the protection device can normally operate to trip and cut off the short circuit fault.
From the above two cases, it is clear that the saturation point measurement of the current transformer must be very accurate, which is of great importance in the power industry.
The saturation point of the conventional current transformer is measured as follows:
the saturation of the current transformer is essentially the magnetic saturation of the current transformer iron cores, the current transformer iron cores with the same materials and process conditions and the saturation current with smaller sectional area is smaller, as shown in A, B of figure 1, the outer diameters of the iron cores B and A are the same, but the inner diameters are different; the cross-sectional area of the iron core B is 4 times larger than that of the iron core a, and the saturation current of the iron core B is 4 times that of the iron core a.
The saturation point is conventionally determined by voltammetry, in particular:
the primary loop is disconnected, current is introduced into the secondary coil, and a current-voltage characteristic curve is obviously divided into two sections; as shown in fig. 2 below: the current and voltage before saturation show an approximately linear relationship, as shown by curve OA, and the current and voltage after saturation also show a near-sighted linear relationship, as shown by curve BC, but the linear relationship with curve OA is significantly different, the slopes of curve OA and curve BC are significantly different (for better understanding by those skilled in the art, curve OA and curve BC are both shown by straight lines in fig. 2), and the slope of curve BC is significantly smaller than the slope of curve OA. The current-voltage linear relation before saturation is not as shown in fig. 3, and the current-voltage linear relation after saturation is immediately transited to in an ideal state, namely, an obvious inflection point does not exist between a curve OA and a curve BC, but as shown in fig. 2, the A, B points are connected through an arc transition curve, and the inflection point is positioned on a transition curve AB; the existing saturation point H is mostly measured by tracing a point on a current-voltage relationship curve, and observing a transition curve AB in fig. 2 to visually determine an inflection point, i.e., the saturation point H.
However, the method for visually measuring the saturation point H of the current transformer obviously has the problems of insufficient accuracy and incapability of being used on intelligent equipment, and for the power industry, the inaccuracy of the measurement of the saturation point H is likely to cause a major accident of burning out a power element; therefore, there is a need for a digital algorithm that can accurately determine the inflection point of the transition curve AB and can be integrated into the smart device program, i.e., the saturation point H.
Disclosure of Invention
The invention aims to provide a method for determining the saturation point of a current transformer based on a maximum offset method so as to solve the problems of insufficient accuracy and incapability of being integrated into an intelligent equipment IED program in a method for visually measuring the saturation point of the current transformer
Is a problem of (a).
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the method for determining the saturation point of the current transformer based on the maximum offset method comprises the following steps of:
step 1: the method comprises the steps of (1) introducing current into a secondary coil of a current transformer to be measured to obtain a current-voltage characteristic curve OC of the secondary coil, wherein O is a coordinate origin, point C is a point randomly selected on a saturated current-voltage linear relation curve, the selection principle of the point C is that the current value of the point C is approximately twice the current value of the saturation point, the current value of the point C is too small to contain the saturation point, and the current transformer is easy to damage when the current value of the point C is too large; definition:
the linear relation of current and voltage before saturation is a curve OA section;
the linear relation of the current and the voltage after saturation is a curve BC segment,
the transition curve is AB section, and the saturation point is H;
step 2: equidistant sampling is carried out from the O point to the C point on a current-voltage characteristic curve OC of the secondary coil, the number of sampling points is N, and the coordinate corresponding to the jth sampling point is (I j ,V j ) Wherein j=1, 2,3, … …, N, I j For the current corresponding to the jth sampling point, V j The voltage corresponding to the j-th sampling point;
the straight line is connected with the point O and the point C to form a straight line OC ', the point C ' and the point C coincide, and the straight line OC ' is defined as an average current-voltage relation straight line; the equation for the average current-voltage relationship line OC' is v=k ′ I, a step of I; wherein V is a dependent variable of an average current-voltage relation line OC ', I is an independent variable of the average current-voltage relation line OC', and k 'is a slope of the average current-voltage relation line OC';
step 3: definition of the jth sample point (I j ,V j ) The perpendicular distance from the average current-voltage relationship line OC' is the offset D j And calculate the offset distance D j Is specified by the value of (a):
step 4: selecting the maximum offset distance D j Is defined as D MAX ，D MAX The current and voltage of the corresponding sampling point are the current value and voltage value of the saturation point H.
N≥20。
The step 4 comprises the following steps:
step 4.1: the j-th sampling point (I j ,V j ) Offset distance D corresponding to the same j Stored as a set of coordinate sets (I j ,V j ,D j ) The coordinate set of the saturation point H is (I) MAX ,V MAX ,D MAX )；
Step 4.2: setting the coordinate set of the saturation point H as (I) MAX ,V MAX ,D MAX ) The initial value is (I MAX ＝0,V MAX ＝0,D MAX ＝0)；
Step 4.3: the coordinates of the first sampling point are combined in sequence (I 1 ,V 1 ,D 1 ) Coordinate set (I) N ,V N ,D N ) Offset distance D in (a) j Is combined with the coordinates of the saturation point H (I MAX ,V MAX ,D MAX ) D in (2) MAX Comparing, if the offset D of the jth sampling point j A value greater than D MAX Then the coordinate set of the j-th sampling point (I j ,V j ,D j ) Coordinate set (I) replacing saturation point H MAX ,V MAX ,D MAX ) Otherwise, the coordinate set of the saturation point H is maintained (I MAX ,V MAX ,D MAX ) Unchanged;
step 4.4: after the comparison of the first to last sampling points, the coordinate set (I MAX ,V MAX ,D MAX ) Middle I MAX ,V MAX Namely, the current value and the voltage value of the saturation point H, D MAX Namely the offset of the saturation point H.
Compared with the prior art, the invention has the beneficial effects that:
compared with the existing method for measuring the saturation point H of the current transformer by visual inspection, the method for determining the saturation point of the current transformer based on the maximum offset method can be directly used in a program of an intelligent instrument, equidistant sampling is carried out on a current-voltage characteristic curve OC of an actually obtained secondary coil, the position of the saturation point H is determined by the maximum offset, and theoretically, the more the number of sampling points is, the more accurate the position of the saturation point H is; in actual work, the number of sampling points can be determined according to the precision requirement, the position of the saturation point H of the current transformer can be accurately determined, the actually measured position of the saturation point H of the current transformer can be compared with the factory position, whether the current transformer is aged or damaged is judged, and the method has very important guiding significance for the work of the power industry.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an iron core a and an iron core B described in the background art;
fig. 2 is a schematic diagram of a current-voltage characteristic curve OC of the secondary coil;
fig. 3 is a schematic diagram of a current-voltage characteristic curve OC of the secondary coil in an ideal state;
fig. 4 is a schematic diagram of the principle of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As shown in fig. 4: the invention discloses a method for determining a saturation point of a current transformer based on a maximum offset method, which comprises the following steps:
step 1: current is introduced into a secondary coil of a current transformer to be measured, and a current-voltage characteristic curve OC of the secondary coil is obtained, wherein O is a coordinate origin, and C is a randomly selected point on a saturated current-voltage linear relation curve; definition:
the linear relation of current and voltage before saturation is a curve OA section;
the linear relation of the current and the voltage after saturation is a curve BC segment,
the transition curve is AB section, and the saturation point is H;
step 2: from the point O to the point C on the current-voltage characteristic curve OC of the secondary coilEquidistant sampling is carried out on the C point, the number of sampling points is N, and the coordinate corresponding to the jth sampling point is (I) j ,V j ) Wherein j=1, 2,3, … …, N, I j For the current corresponding to the jth sampling point, V j The voltage corresponding to the j-th sampling point;
the straight line is connected with the point O and the point C to form a straight line OC ', the point C ' and the point C coincide, and the straight line OC ' is defined as an average current-voltage relation straight line; the equation of the average current-voltage relationship line OC 'is v=k' I; wherein V is a dependent variable of an average current-voltage relation line OC ', I is an independent variable of the average current-voltage relation line OC', and k 'is a slope of the average current-voltage relation line OC';
step 3: definition of the jth sample point (I j ,V j ) The perpendicular distance from the average current-voltage relationship line OC' is the offset D j And calculate the offset distance D j Is specified by the value of (a): according to the j-th sampling point (I j ,V j ) The distance formula to the average current-voltage relationship line OC '(v=k' I), i.e., the point-to-line distance formula, is known:
step 4: selecting the maximum offset distance D j Is defined as D MAX ，D MAX The current and voltage of the corresponding sampling point are the current value and voltage value of the saturation point H.
Preferably, in order to ensure the precision of the saturation point H, the sampling point N is more than or equal to 20; theoretically, the greater the number of N, the higher the accuracy of the saturation point H.
Preferably, the step 4 includes the following steps:
step 4.1: the j-th sampling point (I j ,V j ) Offset distance D corresponding to the same j Stored as a set of coordinate sets (I j ,V j ,D j ) The coordinate set of the saturation point H is (I) MAX ,V MAX ,D MAX )；
Step 4.2: setting the coordinate set of the saturation point H as (I) MAX ,V MAX ,D MAX ) The initial value is (I MAX ＝0,V MAX ＝0,D MAX ＝0)；
Step 4.3: the coordinates of the first sampling point are combined in sequence (I 1 ,V 1 ,D 1 ) Coordinate set (I) N ,V N ,D N ) Offset distance D in (a) j Is combined with the coordinates of the saturation point H (I MAX ,V MAX ,D MAX ) D in (2) MAX Comparing, if the offset D of the jth sampling point j A value greater than D MAX Then the coordinate set of the j-th sampling point (I j ,V j ,D j ) Coordinate set (I) replacing saturation point H MAX ,V MAX ,D MAX ) Otherwise, the coordinate set of the saturation point H is maintained (I MAX ,V MAX ,D MAX ) Unchanged;
step 4.4: after the comparison of the first to last sampling points, the coordinate set (I MAX ,V MAX ,D MAX ) Middle I MAX ,V MAX Namely, the current value and the voltage value of the saturation point H, D MAX Namely, the offset of the saturation point H;
and the step 4 and the programming operation have wider application range.
Examples:
in order to facilitate a better understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will be further described below by using specific examples:
as shown in fig. 4: taking a certain type of current transformer in an ideal state as an example, namely in a current-voltage characteristic curve OC of a secondary coil, the linear relation of current and voltage before saturation is a straight line OA, the linear relation of current and voltage after saturation is a straight line BC, and a saturation point (inflection point) is H, wherein the point A, the point B and the point H are overlapped and are hereinafter called as the point H;
equidistant sampling is carried out from the O point to the C point on a current-voltage characteristic curve OC of the secondary coil, the number of sampling points is 30, and the coordinate corresponding to the jth sampling point is (I j ,V j ) Wherein j=1, 2,3, … …,30, i j For the j-th sampling pointCorresponding current, V j The voltage corresponding to the j-th sampling point;
the straight line is connected with the point O and the point C to form a straight line OC ', the point C ' and the point C coincide, and the straight line OC ' is defined as an average current-voltage relation straight line; the equation of the average current-voltage relationship line OC' isWherein V is a dependent variable of an average current-voltage relation line OC ', I is an independent variable of the average current-voltage relation line OC', and k 'is a slope of the average current-voltage relation line OC';
definition of the jth sample point (I j ,V j ) The perpendicular distance from the average current-voltage relationship line OC' is the offset D j And calculate the offset distance D j Is specified by the value of (a):
as shown in table 1:
table 1 maximum offset method for solving current transformer saturation point-30 sampling point verification table
Selecting the maximum offset distance D j Is defined as D MAX ，D MAX The current and voltage of the corresponding sampling point are the current and voltage values of the saturation point H, and as can be seen from Table 1, the offset D of the 15 th sampling point j The maximum value of (2) is 38.62069, the corresponding voltage is 172.249V, the error is 180-172.249 = 7.751, and the larger error is due to the smaller number of sampling points;
further, when the sampling point is 2000, as shown in table 2:
/>
/>
/>
table 2 maximum offset method for solving current transformer saturation point-2000 sampling point verification table
Selecting the maximum offset distance D j Is defined as D MAX ，D MAX The current and voltage of the corresponding sampling point are the current and voltage values of the saturation point H, and as can be seen from Table 2, the offset D of the 1001 st sampling point j The maximum value of (2) is 39.97998999, which corresponds to a voltage of 179.9482422V, an error of 180-179.91=0.09;
through testing, if voltage is used as a unit of volt (V), current is used as a unit of milliamp (mA), and when the number of sampling points reaches 1000, the error of the measurement result of the saturation point is less than 1 microampere, so that the working requirement is met; the effect of obviously improving the calculation accuracy is not achieved after the sampling point number exceeds 10000.
Compared with the prior art, the invention has the beneficial effects that:
compared with the existing method for measuring the saturation point H of the current transformer by visual inspection, the method for determining the saturation point of the current transformer based on the maximum offset method provided by the invention has the advantages that equidistant sampling is carried out on the current-voltage characteristic curve OC of the secondary coil obtained actually, the position of the saturation point H is determined by the maximum offset, and theoretically, the more the number of sampling points is, the more accurate the position of the saturation point H is; in actual work, the number of sampling points can be determined according to the precision requirement, the position of the saturation point H of the current transformer can be accurately determined, the position of the saturation point H of the current transformer can be compared with the factory position in actual measurement, whether the current transformer is aged or damaged is judged, the intelligent device IED detection method has very important practical guiding significance for the work of the power industry, and the intelligent device IED detection method can be integrated into programs of intelligent device IEDs and has important prospective significance.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the 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 scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (3)
1. The method for determining the saturation point of the current transformer based on the maximum offset method is characterized by comprising the following steps of:
step 1: current is introduced into a secondary coil of a current transformer to be measured, and a current-voltage characteristic curve OC of the secondary coil is obtained, wherein O is a coordinate origin, and C is a randomly selected point on a saturated current-voltage linear relation curve;
definition:
the linear relation of current and voltage before saturation is a curve OA section;
the linear relation of the current and the voltage after saturation is a curve BC segment;
the transition curve is AB section, and the saturation point is H;
step 2: equidistant sampling is carried out from the O point to the C point on a current-voltage characteristic curve OC of the secondary coil, the number of sampling points is N, and the coordinate corresponding to the jth sampling point is (I j ，V j ) Wherein j=1, 2,3, … …, N, I j For the current corresponding to the jth sampling point, V j The voltage corresponding to the j-th sampling point;
the straight line is connected with the point O and the point C to form a straight line OC ', the point C ' and the point C coincide, and the straight line OC ' is defined as an average current-voltage relation straight line; the equation of the average current-voltage relationship line OC 'is v=k' I; wherein V is a dependent variable of an average current-voltage relation line OC ', I is an independent variable of the average current-voltage relation line OC', and k 'is a slope of the average current-voltage relation line OC';
step 3: definition of the jth sample point (I j ，V j ) The perpendicular distance from the average current-voltage relationship line OC' is the offset D j And calculate the offset distance D j Is specified by the value of (a):
step 4: selecting the maximum offset distance D j Is defined as D MAX ，D MAX The current and voltage of the corresponding sampling point are the current value and voltage value of the saturation point H.
2. The method for determining the saturation point of the current transformer based on the maximum offset method according to claim 1, wherein: n is more than or equal to 20.
3. The method for determining the saturation point of the current transformer based on the maximum offset method according to claim 1, wherein: the step 4 comprises the following steps:
step 4.1: the j-th sampling point (I j ，V j ) Offset distance D corresponding to the same j Stored as a coordinate systemGroup (I) j ，V j ，D j ) The coordinate set of the saturation point H is (I) MAX ，V MAX ，D MAX )；
Step 4.2: setting the coordinate set of the saturation point H as (I) MAX ，V MAX ，D MAX ) The initial value is (I MAX ＝0，V MAX ＝0，D MAX ＝0)；
Step 4.3: the coordinates of the first sampling point are combined in sequence (I 1 ，V 1 ，D 1 ) Coordinate set (I) N ，V M ，D N ) Offset distance D in (a) j Is combined with the coordinates of the saturation point H (I MAX ，V MAX ，D MAX ) D in (2) MAX Comparing, if the offset D of the jth sampling point j A value greater than D MAX Then the coordinate set of the j-th sampling point (I j ，V j ，D j ) Coordinate set (I) replacing saturation point H MAX ，V MAX ，D MAX ) Otherwise, the coordinate set of the saturation point H is maintained (I MAX ，V MAX ，D MAX ) Unchanged;
step 4.4: after the comparison of the first to last sampling points, the coordinate set (I MAX ，V MAX ，D MAX ) Middle I MAX ，V MAX Namely, the current value and the voltage value of the saturation point H, D MAX Namely the offset of the saturation point H.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110716000.1A CN113589212B (en) | 2021-06-24 | 2021-06-24 | Method for determining saturation point of current transformer based on maximum offset method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110716000.1A CN113589212B (en) | 2021-06-24 | 2021-06-24 | Method for determining saturation point of current transformer based on maximum offset method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113589212A CN113589212A (en) | 2021-11-02 |
| CN113589212B true CN113589212B (en) | 2024-02-06 |
Family
ID=78244683
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110716000.1A Active CN113589212B (en) | 2021-06-24 | 2021-06-24 | Method for determining saturation point of current transformer based on maximum offset method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113589212B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20050059002A (en) * | 2004-12-31 | 2005-06-17 | 명지대학교 | Method for compensating secondary current of current transformers |
| WO2014063570A1 (en) * | 2012-10-24 | 2014-05-01 | 国家电网公司 | Method for on-line diagnosing gradually-changing fault of electronic current transformers |
| CN105067906A (en) * | 2015-07-20 | 2015-11-18 | 贵州电网有限责任公司电力调度控制中心 | Method for detecting saturation of current transformer (CT) on the basis of third-order central moment |
| CN105137380A (en) * | 2015-07-20 | 2015-12-09 | 贵州电网有限责任公司电力调度控制中心 | Protective current transformer saturation detection method based on skewed distribution |
-
2021
- 2021-06-24 CN CN202110716000.1A patent/CN113589212B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20050059002A (en) * | 2004-12-31 | 2005-06-17 | 명지대학교 | Method for compensating secondary current of current transformers |
| WO2014063570A1 (en) * | 2012-10-24 | 2014-05-01 | 国家电网公司 | Method for on-line diagnosing gradually-changing fault of electronic current transformers |
| CN105067906A (en) * | 2015-07-20 | 2015-11-18 | 贵州电网有限责任公司电力调度控制中心 | Method for detecting saturation of current transformer (CT) on the basis of third-order central moment |
| CN105137380A (en) * | 2015-07-20 | 2015-12-09 | 贵州电网有限责任公司电力调度控制中心 | Protective current transformer saturation detection method based on skewed distribution |
Non-Patent Citations (1)
| Title |
|---|
| 基于分段拟合算法的电流互感器误差研究;周雪青;郝晓光;张岩坡;赵宇皓;;电力***保护与控制(第03期);139-143 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113589212A (en) | 2021-11-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3069426B1 (en) | Method and apparatus of reactor turn-to-turn protection | |
| CN110456299B (en) | On-line detection method for turn-to-turn short circuit fault of secondary winding of current transformer | |
| CN102540128B (en) | Method for automatically calibrating error of combined three-phase current transformer | |
| CN103235280B (en) | Direct measuring method of magnetic saturation margin of current transformer based on scaling converter | |
| CN105044649B (en) | A kind of current transformer error horizontal dynamic detection method and system | |
| CN106291123A (en) | A kind of method of direct measurement magnetic cell winding loss | |
| CN112180299A (en) | 10kV distribution transformer turn-to-turn short circuit fault online monitoring method | |
| Wu et al. | Residual flux measurement of power transformer based on transient current difference | |
| Karmakar et al. | Machine learning approach to estimation of internal parameters of a single phase transformer | |
| CN112304207A (en) | Transformer winding deformation online detection method by using leakage inductance parameter change estimation | |
| CN113589212B (en) | Method for determining saturation point of current transformer based on maximum offset method | |
| Yang et al. | Influence of high voltage DC transmission on measuring accuracy of current transformers | |
| CN111965569B (en) | DC magnetic bias level measurement method, device and system for online operation transformer | |
| CN107102229B (en) | Method for realizing transformer model for no-load switching transient calculation | |
| CN107544045B (en) | System and method for detecting error of self-correcting current transformer | |
| CN106199164B (en) | A kind of measurement method of transformer iron core grounding current | |
| CN113376561A (en) | Electric energy metering device remote calibration system based on peer comparison mode | |
| CN110927516B (en) | Power distribution network single-phase earth fault identification method and system based on grounding transformer tap grounding | |
| CN208172234U (en) | A kind of no-load voltage ratio of current transformer, Check up polarity experimental rig | |
| CN104111438B (en) | Primary large-current loop monitoring method in current transformer error test | |
| Xu et al. | On-line monitoring of winding deformation of power transformer | |
| CN107589330A (en) | A kind of electrification detection system and method for power transformer loss | |
| CN117031142A (en) | Method for measuring saturation point of iron core by bidirectional approximation mean value method | |
| Hu et al. | Detecting the capacity of distribution transformer based on an on-line method | |
| CN109444527A (en) | The medium-term and long-term voltage stability monitoring method of the electric system containing dynamic element |
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 |