CN115267640A - Current transformer abnormity checking method, system, equipment and medium - Google Patents
Current transformer abnormity checking method, system, equipment and medium Download PDFInfo
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Abstract
The invention discloses a current transformer abnormity checking method, a system, equipment and a medium, which respond to a current transformer checking request, collect basic data and measurement data of a transformer to be tested, determine checking data corresponding to the current transformer checking request according to the basic data and the measurement data, calculate the relative error rate of the measurement data, judge whether the wiring of the current transformer is abnormal according to the relative error rate and the type of the current transformer, and simultaneously determine the position of the current transformer with abnormal wiring according to the measurement data, thereby improving the accuracy of judging the abnormal wiring of the current transformer and improving the reliability of the relay protection operation of a power system.
Description
Technical Field
The invention relates to the technical field of current transformer abnormity verification, in particular to a current transformer abnormity verification method, a system, equipment and a medium.
Background
The transformer is an important electrical device in the power system, and whether the transformer is safely operated or not is directly related to whether the power system can continuously and stably work or not. The normal operation of the power supply system is directly influenced by the correctness of the wiring of the differential protection circuit of the conventional transformer. The method is an essential important link in the commissioning and maintenance of the transformer substation by analyzing the correctness of the differential protection circuit wiring in time.
Therefore, in the prior art, the wiring correctness of the secondary circuit of the current transformer is mainly judged by short-circuiting the low-voltage side of the transformer, then introducing 380V voltage of mains supply to the high-voltage side or the medium-voltage side, measuring the current magnitude and the phase of the secondary winding of each current transformer by using a phase meter, and manually drawing a hexagonal diagram.
However, in the prior art, calculation is performed manually, a hexagonal diagram is drawn manually, and then a result of the secondary circuit wiring analysis of the current transformer is obtained according to the calculation result. The whole analysis process is large in calculation amount and needs workers to judge according to experience, and the defect of large error exists, so that the reliability of relay protection operation of the power system is low.
Disclosure of Invention
The invention provides a method, a system, equipment and a medium for checking the abnormity of a current transformer, which solve the problem that the reliability of relay protection operation of a power system is lower due to the fact that the error is larger in the judgment of the wiring correctness of a secondary circuit of the current transformer by depending on personal experience and subjective judgment of workers in the prior art.
The invention provides a method and a system for checking abnormality of a current transformer, and relates to a transformer to be tested, wherein the transformer to be tested is connected with the current transformer; the method comprises the following steps:
responding to a current transformer checking request, and collecting basic data and measurement data of the transformer to be measured;
determining verification data corresponding to the current transformer verification request according to the basic data and the measurement data;
calculating a relative error rate of the measurement data;
judging whether the wiring of the current transformer is abnormal or not according to the relative error rate and the type of the current transformer;
and if the wiring of the current transformer is judged to be abnormal, determining the abnormal wiring position of the current transformer based on the measurement data.
Optionally, the step of collecting the basic data and the measurement data of the transformer to be tested in response to the current transformer verification request includes:
responding to a current transformer checking request, connecting an output end of a preset transformer short-circuit test device to a high-voltage side of the transformer to be tested, and connecting an input end of the transformer short-circuit test device to a mains supply three-phase socket to form a transformer short-circuit test loop and conduct the transformer short-circuit test loop;
acquiring measurement data of the transformer to be tested through the transformer test device; the measurement data comprises a high-voltage side primary current, a high-voltage side secondary current, a differential current sampling value of a differential protection device, a high-voltage side three-phase and a low-voltage side three-phase;
acquiring basic data of the transformer to be tested; the basic data comprises rated capacity of the transformer, rated voltage of a high-voltage side, short-circuit impedance, transformation ratio of a current transformer at the high-voltage side and interphase voltage at the high-voltage side of the transformer.
Optionally, the verification data includes a theoretical value of a primary current on the high-voltage side and a theoretical value of a secondary current on the high-voltage side; the step of determining the verification data corresponding to the current transformer verification request according to the basic data and the measurement data comprises the following steps:
substituting the basic data and the measurement data into a high-voltage side primary current calculation formula to calculate a high-voltage side primary current theoretical value;
the high-voltage side primary current calculation formula specifically comprises:
wherein,X T is the transformer impedance, U is the interphase voltage on the high-voltage side of the transformer, U d % is short-circuit impedance, S e Rated capacity of transformer, U he For the high-side voltage rating, I h1 Is a theoretical value of primary current at a high-voltage side;
and calculating the ratio of the high-voltage side primary current theoretical value to the high-voltage side current transformer transformation ratio to obtain a high-voltage side secondary current theoretical value.
Optionally, the step of calculating a relative error rate of the measurement data comprises:
calculating a first difference value of the high-voltage side three-phase and a high-voltage side three-phase theoretical value, and determining the ratio of the first difference value to the high-voltage side three-phase theoretical value as a first relative error rate;
calculating a second difference value between the low-voltage side three-phase and the low-voltage side three-phase theoretical value, and determining the ratio of the second difference value to the low-voltage side three-phase theoretical value as a second relative error rate;
and calculating a third difference value of the high-voltage side secondary current and the theoretical value of the high-voltage side secondary current, and determining the ratio of the third difference value to the theoretical value of the high-voltage side secondary current as a third phase error rate.
Optionally, when the current transformer is a differential winding current transformer, the step of determining whether the connection of the current transformer is abnormal according to the relative error rate and the type of the current transformer includes:
comparing whether the difference flow sampling value is less than or equal to a preset difference flow threshold value;
if not, judging that the current transformer is abnormal in wiring;
if yes, judging whether the first relative error rate is equal to a preset phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the current transformer is normal in wiring;
and if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal.
Optionally, when the current transformer is another current transformer, the step of determining whether the wiring of the current transformer is abnormal according to the relative error rate and the type of the current transformer includes:
judging whether the current transformer is a low-voltage side current transformer or not;
if the current transformer is the low-voltage side current transformer, judging whether the second relative error rate is equal to a preset phase difference threshold value or not;
if the second relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
if the second relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal;
if the current transformer is not the low-voltage side current transformer, judging whether the first relative error rate is equal to a phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
and if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal.
Optionally, the method further comprises:
judging whether the third phase error rate is larger than a preset high-voltage current threshold value or not;
if so, judging that the current transformer has a fault;
if not, judging that the current transformer is normal.
The invention provides a current transformer abnormity checking system in a second aspect, which relates to a transformer to be tested, wherein the transformer to be tested comprises a current transformer; the system comprises:
the data acquisition module is used for receiving a current transformer check request and acquiring basic data and measurement data of the transformer to be measured;
the acquisition module is used for determining verification data corresponding to the current transformer verification request according to the basic data and the measurement data;
an automatic calculation module for calculating a relative error rate of the measurement data;
the judging module is used for judging whether the wiring of the current transformer is abnormal or not according to the relative error rate and the type of the current transformer;
and the analysis module is used for determining the abnormal wiring position of the current transformer based on the measurement data if the abnormal wiring of the current transformer is judged.
A third aspect of the present invention provides an electronic device, including a memory and a processor, where the memory stores a computer program, and the computer program, when executed by the processor, causes the processor to execute the steps of the current transformer abnormality checking method according to any one of the above-mentioned embodiments.
A fourth aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, the computer program, when executed, implementing a current transformer abnormality checking method as described in any one of the above.
According to the technical scheme, the invention has the following advantages:
the method comprises the steps of responding to a current transformer checking request, acquiring basic data and measurement data of a transformer to be tested, determining checking data corresponding to the current transformer checking request according to the basic data and the measurement data, calculating a relative error rate of the measurement data, judging whether the wiring of the current transformer is abnormal or not according to the relative error rate, and determining the abnormal wiring position of the current transformer based on the measurement data if the wiring of the current transformer is abnormal, so that the technical problem that the reliability of relay protection operation of a power system is low due to the fact that the hexagonal diagram is drawn manually by means of manual calculation when the wiring of the current transformer is judged to be abnormal is solved. According to the method, the basic data and the measurement data of the transformer connected with the current transformer to be detected are collected, the relative error rate of the measurement data is calculated, whether the current transformer is abnormal or not is judged according to the relative error rate, meanwhile, the abnormal wiring position of the current transformer can be determined according to the abnormal measurement data, the accuracy of judging whether the wiring of the current transformer is abnormal or not is effectively improved, and therefore the reliability of relay protection operation of a power system is improved.
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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 embodiments or the description of the prior art will be briefly described below, 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 the drawings without inventive labor.
Fig. 1 is a flowchart illustrating steps of a method for checking an abnormality of a current transformer according to an embodiment of the present invention;
fig. 2 is a flowchart illustrating steps of a current transformer abnormality checking method according to a second embodiment of the present invention;
fig. 3 is a block diagram of a current transformer abnormality checking system according to a third embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a method, a system, equipment and a medium for checking the abnormity of a current transformer, which are used for solving the technical problem that the reliability of the relay protection operation of a power system is lower due to the defect that the error is larger when the correctness of the secondary circuit wiring of the current transformer is judged by depending on the personal experience and subjective judgment of workers in the prior art.
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.
Referring to fig. 1, fig. 1 is a flowchart illustrating a method for checking an abnormality of a current transformer according to an embodiment of the present invention.
The invention provides a method for checking the abnormity of a current transformer, which comprises the following steps:
the current transformer checking request refers to a request for judging whether the current transformer is abnormally connected or not, which is sent for verifying the wiring correctness of the current transformer after the current transformer is installed by a worker. For example, whether the current transformer is abnormal or not and the position of the current transformer is abnormal are judged.
The basic data refers to various parameters of the transformer to be tested connected with the current transformer in a rated state, such as rated capacity of the transformer, rated voltage of a high-voltage side, short-circuit impedance, transformation ratio of the high-voltage side current transformer and phase-to-phase voltage of the high-voltage side of the transformer.
The measured data refers to various parameters obtained by measurement when the current transformer is checked by a transformer to be measured connected with the current transformer, such as primary current on the high-voltage side of the transformer, secondary current on the high-voltage side of the transformer, a differential current sampling value of a differential protection device, a three-phase on the high-voltage side and a three-phase on the low-voltage side.
In this embodiment, when a current transformer verification request sent by a fault person is received, the request is read, the position of the current transformer is obtained, the transformer connected with the current transformer is used as the transformer to be measured, and basic data and measurement data of the transformer to be measured are obtained.
102, determining verification data corresponding to the current transformer verification request according to the basic data and the measurement data;
the checking data refer to parameters related to conversion of a large current on one side into a secondary low-voltage current by the current transformer according to the electromagnetic induction principle when the current transformer normally works, and the parameters are used for judging whether the current transformer breaks down or not. Including but not limited to a high side primary current theoretical value and a high side secondary current theoretical value.
In the embodiment of the application, after basic data and measurement data of a transformer to be tested are obtained, data required to be calculated are determined to be a high-voltage side primary current theoretical value and a high-voltage side secondary current theoretical value according to a current transformer checking request, basic data and measurement data related to calculation of the high-voltage side primary current and the high-voltage side secondary current are extracted, the high-voltage side primary current theoretical value and the high-voltage side secondary current theoretical value are calculated, and the calculated high-voltage side primary current theoretical value and the calculated high-voltage side secondary current theoretical value are determined to be checking data.
It should be noted that the data content, which is included in the current transformer verification request and needs to be acquired for current transformer verification, includes basic data, measurement data and verification data.
the relative error rate refers to the error between the measured data and the theoretical value, can exactly represent the actual deviation of the measured value from the theoretical value, and is the basis for judging whether the current transformer is abnormal or not.
The measured data refers to data obtained by measuring when the current transformer is connected to be tested in a checking way and works actually. Such as high side three phase, low side three phase, high side secondary current.
The theoretical value refers to a basic parameter of the transformer to be tested connected with the current transformer in a rated state or calibration data obtained through secondary calculation of basic data and measurement data, such as a high-voltage side three-phase theoretical value, a low-voltage side three-phase theoretical value and a high-voltage side secondary current theoretical value.
In the embodiment of the application, the measured data and the theoretical value are obtained, the difference between the measured data and the theoretical value is calculated, the ratio of the difference to the theoretical value is calculated, and the relative error rate of the measured data is calculated.
104, judging whether the wiring of the current transformer is abnormal or not according to the relative error rate and the type of the current transformer;
in the real-time example, because the current transformers are of various types, after the relative error rate is obtained, the type of the current transformer needs to be judged, and after the type of the current transformer is judged, whether the wiring of the current transformer is abnormal or not is judged according to the relative error rate of the wiring type of the current transformer and the relative error rate of the current transformer in normal working.
The relative error rate corresponds to the wiring type of the current transformer, for example, whether the current transformer points to a first relative error rate corresponding to a main transformer or not, and whether the current transformer points to a second relative error rate corresponding to a bus or not.
It should be noted that the types of current transformers include various types, such as differential winding current transformers, other current transformers, and low-voltage side current transformers.
105, if the wiring of the current transformer is judged to be abnormal, determining the abnormal wiring position of the current transformer based on the measurement data;
in the embodiment of the application, after the wiring abnormality of the current transformer is judged, a relative error rate or a differential sampling value corresponding to the wiring abnormality of the current transformer can be obtained, measurement data of the wiring abnormality of the current transformer can be obtained according to a relative error rate calculation formula or the differential sampling value, different measurement data correspond to different wiring position current transformers, and the wiring positions corresponding to the current transformers can be matched according to the abnormal measurement data. For example, the measurement data corresponding to the main transformer current transformer is a high-voltage side three-phase, the measurement data corresponding to the bus current transformer is a low-voltage side three-phase, and the measurement data corresponding to the current transformer at the differential winding is a differential sampling value.
It should be noted that the high-voltage side three-phase data abnormality indicates that a current transformer pointing to a main transformer position is connected with a low-voltage side three-phase or a current transformer pointing to a main transformer position is connected with a high-voltage side other phase to cause a high-voltage side three-phase imbalance, so that the current transformer pointing to a main transformer at an abnormal position can be determined according to the high-voltage side three-phase data abnormality, the current transformer pointing to a bus position is connected with the high-voltage side three-phase or the current transformer pointing to a bus position is connected with the low-voltage side other phase to cause the low-voltage side three-phase imbalance, so that the current transformer pointing to a bus at an abnormal position can be determined according to the low-voltage side three-phase data abnormality, the differential sampling value data is directly read from the current transformer at the differential winding, and it indicates that the primary side current and the secondary side current have an excessive difference due to the fact that a certain position of the current transformer is connected with other positions, so that the current transformer at the differential winding is determined according to the differential sampling value abnormality.
In the embodiment of the invention, when a current transformer checking request sent by a fault person is received, the request is read to obtain the position of the current transformer, the transformer connected with the current transformer is used as a transformer to be tested, basic data and measurement data of the transformer to be tested are obtained, the data to be calculated is determined to be a high-voltage side primary current theoretical value, a current theoretical value and a high-voltage side secondary current theoretical value according to the current transformer checking request, the high-voltage side primary current theoretical value and the high-voltage side secondary current theoretical value are calculated by obtaining the basic data and the measurement data, the calculated high-voltage side primary current theoretical value and the calculated high-voltage side secondary current theoretical value are determined to be checking data, the ratio of the difference value to the theoretical value is calculated by calculating the difference value of the measurement data and the theoretical value, the type of the current transformer is judged, after the type of the current transformer is judged, the relative error rate corresponding to the current transformer wiring type is obtained, whether the wiring of the current transformer is abnormal is judged by combining the relative error rate when the current transformer normally works, after the wiring of the current transformer is judged, the abnormal, the measurement data corresponding to different wiring positions of the current transformer can be matched according to the current transformer. In the whole process, the wiring of the current transformer can be accurately checked without manually drawing a hexagonal diagram by a worker, so that the wiring correctness of the current transformer is improved, and the reliability of relay protection operation of a power system is improved.
Referring to fig. 2, fig. 2 is a flowchart illustrating steps of a current transformer abnormality checking method according to a second embodiment of the present invention.
further, step 201 may comprise the following sub-steps:
responding to a current transformer checking request, connecting the output end of a preset transformer short-circuit test device to the high-voltage side of a transformer to be tested, and connecting the input end of the transformer short-circuit test device to a mains supply three-phase socket to form a transformer short-circuit test loop and conduct the transformer short-circuit test loop;
acquiring measurement data of a transformer to be measured through a transformer test device; the measured data comprises a high-voltage side primary current, a high-voltage side secondary current, a differential current sampling value of a differential protection device, a high-voltage side three-phase and a low-voltage side three-phase;
acquiring basic data of a transformer to be tested; the basic data comprises rated capacity of the transformer, rated voltage of a high-voltage side, short-circuit impedance, transformation ratio of a current transformer at the high-voltage side and interphase voltage at the high-voltage side of the transformer.
The preset transformer short-circuit test device is a transformer short-circuit test device which is composed of an intelligent digital phase meter, a current clamp, a test wire, a three-phase linkage voltage air switch, a USB charger and a USB charging wire.
In the embodiment of the application, when a current transformer check request is received, the current transformer check request is responded, the high-voltage side of the related transformer to be tested is connected with the output end of a transformer short-circuit test device, the input end of the transformer short-circuit test device is connected to a mains supply three-phase socket to form a transformer short-circuit test loop, three connecting voltage is closed, the voltage is opened and closed to enable the transformer short-circuit test loop to be conducted, the high-voltage side three-phase and the low-voltage side three-phase can be read from an intelligent digital phase table in the short-circuit test device, and a current clamp reads differential current sampling values on a primary current of the high-voltage side of the transformer to be tested, a secondary current of the high-voltage side of the transformer to be tested and a differential current transformer on a differential winding current transformer.
And 202, substituting the basic data and the measurement data into a high-voltage side primary current calculation formula to calculate a high-voltage side primary current theoretical value.
The high-voltage side primary current calculation formula is specifically as follows:
wherein,XT is the transformer impedance, U is the interphase voltage at the high-voltage side of the transformer, ud% is the short-circuit impedance, S e Rated capacity, U, of the transformer he For the high-side voltage rating, I h1 Is a theoretical value of the primary current at the high-voltage side.
The high-voltage side primary current theoretical value refers to the current value of the high-voltage side when the transformer to be measured runs in a rated state.
In the embodiment of the application, the theoretical value of the high-voltage primary current cannot be directly obtained from the transformer to be measured, and the interphase voltage U and the short-circuit impedance U at the high-voltage side of the transformer need to be screened from the obtained measurement data and basic data d Percent, rated capacity S of transformer e High side rated voltage U he And determining a theoretical value of the high-voltage primary side current.
And 203, calculating the ratio of the high-voltage side primary current theoretical value to the high-voltage side current transformer transformation ratio to obtain a high-voltage side secondary current theoretical value.
The transformation ratio of the high-voltage side current transformer refers to the ratio of primary current to secondary current of the current transformer in a rated state.
The high-voltage side secondary current theoretical value refers to a current value for converting a high-voltage side primary current into a secondary current in a rated state of the current transformer.
In the embodiment of the application, after the theoretical value of the primary current of the high-voltage side is calculated, the theoretical value of the secondary current of the high-voltage side is determined according to the transformation ratio of the current transformer of the high-voltage side, and because the working principle of the current transformer is that the primary current is converted into the secondary current of the high-voltage side, if the difference between the secondary current of the high-voltage side and a rated value exceeds a certain range, the current transformer is indicated to have a fault, and therefore the theoretical value of the secondary current of the high-voltage side can be used as one of judgment factors for judging whether the current transformer has the fault.
optionally, step 204 comprises the following sub-steps S11-S13:
s11, calculating a first difference value between the high-voltage side three-phase and the high-voltage side three-phase theoretical value, and determining the ratio of the first difference value to the high-voltage side three-phase theoretical value as a first relative error rate.
The high-side three-phase refers to a phase relationship between three phase currents, for example, a high-side a phase difference with respect to a phase B, a high-side a phase difference with respect to a phase C, and a high-side B phase difference with respect to a phase C.
The high-voltage side three-phase theoretical value refers to a phase relation among three-phase currents under the condition that wiring of the current transformer is not abnormal, for example, if the phase difference of a high-voltage side A relative to a phase B is 120 degrees, the phase difference of the high-voltage side A relative to a phase C is 240 degrees, and the phase difference of the high-voltage side B relative to the phase C is 120 degrees.
In the embodiment of the application, the high-voltage side three-phase is the phase difference I between the high-voltage side A and the B phase AB Phase difference I between high-voltage side A and C AC Phase difference I between high-voltage side A and C BC When the wiring of the power transformer points to the main transformer, the high-voltage sideThe theoretical value of the phase difference between A phase and C phase is equal to (I) AB+ 120 DEG, calculating the phase difference I between the high-pressure side A and the C AC Phase difference theoretical value (I) from high pressure side A to C AB+ A difference of 120 degrees to obtain a first difference, and comparing the first difference with a theoretical value (I) of phase difference of high-pressure side A relative to C AB+ The ratio of 120 DEG is determined as a first relative error rate which is a basis for whether the current transformer points to a main transformer.
And S12, calculating a second difference value between the low-voltage side three-phase and the low-voltage side three-phase theoretical value, and determining the ratio of the second difference value to the low-voltage side three-phase theoretical value as a second relative error rate.
The low-voltage three-phase refers to a phase relationship between three phase currents, for example, a low-voltage side a phase difference with respect to a phase b, a low-voltage side a phase difference with respect to a phase c, and a low-voltage side b phase difference with respect to a phase c.
The low-voltage side three-phase theoretical value refers to a phase relationship between three-phase currents in the case where there is no abnormality in the current transformer wiring, for example, if the low-voltage side a is 120 degrees different from the b-phase theoretical value, the low-voltage side a is 240 degrees different from the c-phase theoretical value, and the low-voltage side b is 120 degrees different from the c-phase theoretical value.
In the embodiment of the application, the low-voltage side three-phase is the phase difference I between the a phase and the b phase of the low-voltage side ab Phase difference I between a on the low-voltage side and c ac Phase difference I between low-voltage side a and c bc When the wiring of the power transformer points to the bus, the phase difference theoretical value of the low-voltage side a relative to the phase c is equal to (I) ab+ 120 DEG, calculating the phase difference I of the low-voltage side a relative to the phase c AC Phase difference theoretical value (I) from low-voltage side a to c ab+ A difference of 120 degrees is obtained to obtain a second difference, and the second difference is compared with a phase difference theoretical value (I) of a relative c phase of a low-voltage side a ab+ The ratio of 120 deg.) is determined as a second relative error rate, which is a basis for whether the current transformer is pointed at the bus.
And S13, calculating a third difference value between the high-voltage side secondary current and the theoretical value of the high-voltage side secondary current, and determining the ratio of the third difference value to the theoretical value of the high-voltage side secondary current as a third relative error rate.
The high-voltage side secondary current means that the high-voltage side primary current is converted into the high-voltage side secondary current through a current transformer.
The high-voltage side secondary current theoretical value refers to a high-voltage side secondary current value obtained by converting a high-voltage side primary current through a current transformer under the condition that the current transformer is not damaged.
In the embodiment of the application, the measured high-voltage side secondary current value is obtained, the high-voltage side secondary current theoretical value is obtained through secondary calculation, the difference value between the high-voltage side secondary current and the high-voltage side secondary current theoretical value is calculated, a third difference value is obtained, the ratio of the third difference value to the high-voltage side secondary current theoretical value is determined as a third phase error rate, and the third phase error rate is a basis for judging whether the current transformer works normally.
optionally, step 204 comprises the following sub-S21-S22 steps:
s21, judging whether the current transformer is a differential current transformer or not;
when the current transformer is a differential winding current transformer, comparing whether a differential current sampling value is less than or equal to a preset differential current threshold value;
comparing whether the difference flow sampling value is less than or equal to a preset difference flow threshold value;
if not, judging that the current transformer is abnormal in wiring;
if so, judging whether the first relative error rate is equal to a preset phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
and if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal.
And the differential current threshold value refers to a critical value of the differential winding current transformer in abnormal wiring, is used for comparing with the differential current sampling value, judging whether the differential winding current transformer is abnormal in wiring or not, and is specifically set according to actual requirements.
And the phase difference threshold value refers to a critical value of the actual phase difference and the theoretical phase difference error rate when the current transformer points to the main transformer, is used for comparing with the first relative error rate and judging whether the current transformer points to the main transformer or not, and is set to be 0.
In the embodiment of the invention, when the current transformer is a differential winding current transformer, a differential sampling value and a first relative error rate are obtained, whether the differential sampling value is greater than or equal to a differential threshold value or not is judged, if the differential sampling value is greater than or equal to the differential threshold value, the differential winding current transformer is abnormal, if the differential sampling value is less than the differential threshold value, the differential winding current transformer is considered to be normally wired, and whether the current transformer points to a main transformer or not is judged by judging whether the first relative error rate is greater than 0 or not, if the first relative error rate is greater than 0, the current transformer is considered to be abnormal in wiring, and if the first relative error rate is equal to 0, the current transformer is normal in wiring.
S22, when the current transformer is other current transformers, judging whether the current transformer is a low-voltage side current transformer;
if the current transformer is a low-voltage side current transformer, judging whether a second relative error rate is equal to a preset phase difference threshold value or not;
if the second relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
if the second relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal;
if the current transformer is not a low-voltage side current transformer, judging whether the first relative error rate is equal to a phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
and if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal.
In the embodiment of the invention, when the current transformer is another current transformer, whether the current transformer points to a main transformer or a bus needs to be judged, if the current transformer is a low-voltage side winding current transformer, the current transformer points to the bus, whether a second relative error rate is greater than 0 is judged, if the second relative error rate is greater than 0, the current transformer is considered to be abnormal, if the second relative error rate is less than 0, the current transformer points to the bus, if the current transformer is not a low-voltage measurement winding current transformer, the current transformer is considered to point to the main transformer, whether a first relative error rate is greater than 0 is judged, if the first relative error rate is greater than 0, the current transformer is considered to be abnormal in wiring, and if the first relative error rate is equal to 0, the current transformer is in wiring normally.
It should be noted that, two ends of the transformer are divided into a high-voltage side and a low-voltage side, and only when the current transformer is a low-voltage side winding current transformer, the current transformer can point to the bus, and in other cases, the current transformer is all pointing to the main transformer.
in the implementation of the application, when the wiring of the current transformer is judged to be abnormal, the measurement data of the abnormal wiring of the current transformer is output, if the abnormal measurement data is a differential sampling value, the current transformer of the differential winding is judged to be abnormal, if the abnormal measurement data is a high-voltage side three-phase, the current transformer pointing to the main transformer is judged to be abnormal, and if the abnormal measurement data is a low-voltage side three-phase, the current transformer pointing to the bus is judged to be abnormal.
It should be noted that the differential current sampling value is acquired by measuring data of the differential winding current transformer, and if the differential current sampling value is abnormal, it indicates that the high-voltage side secondary connection and the low-voltage side secondary connection of the differential winding current transformer are inconsistent, it is considered that the differential winding current transformer is abnormal in connection. When the current transformer points to the main transformer, the phase difference between the three phases at the high-voltage side of the current transformer is 120 degrees, if the data of the three phases at the high-voltage side are abnormal, the phase difference between the three phases at the high-voltage side is not equal to 120 degrees, the current transformer is connected with other lines, so that the phase difference between the three phases at the high-voltage side is not equal to 120 degrees, and the current transformer points to the main transformer abnormally. When the current transformer points to the bus, the phase difference between the low-voltage three-phase phases of the current transformer should be 120 degrees, if the data of the low-voltage three-phase phases are abnormal, the phase difference between the low-voltage three-phase phases is not equal to 120 degrees, the current transformer is connected with other lines, the phase difference between the low-voltage three-phase phases is not equal to 120 degrees, and the current transformer points to the main transformer and is abnormal.
Further, whether the current transformer has a fault or not can be judged according to the relative error rate;
judging whether the third phase error rate is larger than a preset high-voltage current threshold value or not;
if the third phase error rate is larger than the preset high-voltage current threshold value, judging that the current transformer has a fault;
and if the third phase error rate is less than or equal to the preset high-voltage current threshold value, judging that the current transformer has no fault.
The high-voltage current threshold is a critical value of an error rate of a measured value of the high-voltage secondary side and a theoretical value of the high-voltage secondary side when the current transformer works normally, and is used for judging whether the current transformer fails, and the high-voltage current threshold is 1%.
In the embodiment of the application, a difference value between the theoretical values of the high-voltage side secondary current and the high-voltage side secondary current is calculated and determined as a third difference value, a ratio of the third difference value to the theoretical value of the high-voltage side secondary current is determined as a third relative error rate, whether the third relative error rate is greater than 1% or not is judged, if the third relative error rate is greater than 1%, the current transformer fails, and if the third relative error list is less than or equal to 1%, the current transformer is judged not to fail.
It should be noted that, because the high-voltage-side secondary current is obtained by performing secondary conversion on the high-voltage-side primary current through the current transformer, when the current transformer normally works, the high-voltage-side secondary current obtained by performing secondary conversion on the high-voltage-side primary current through the current transformer is a stable value, and the third phase error rate actually represents an error rate between the high-voltage-side secondary current and a theoretical value, when the third phase error rate changes greatly, it indicates that the transformation ratio error of the current transformer is large, and it indicates that the current transformer has a fault.
In the embodiment of the invention, when a current transformer checking request sent by a fault person is received, the request is read to obtain the position of the current transformer, the transformer connected with the current transformer is used as a transformer to be tested, basic data and measurement data of the transformer to be tested are obtained, the data to be calculated is determined to be a high-voltage side primary current theoretical value, a current theoretical value and a high-voltage side secondary current theoretical value according to the current transformer checking request, the high-voltage side primary current theoretical value and the high-voltage side secondary current theoretical value are calculated by obtaining the basic data and the measurement data, the calculated high-voltage side primary current theoretical value and the calculated high-voltage side secondary current theoretical value are determined to be checking data, the ratio of the difference value to the theoretical value is calculated by calculating the difference value of the measurement data and the theoretical value, the type of the current transformer is judged, after the type of the current transformer is judged, the relative error rate corresponding to the current transformer wiring type is obtained, whether the wiring of the current transformer is abnormal is judged by combining the relative error rate when the current transformer works normally, after the wiring of the current transformer is judged, the abnormal, the measurement data corresponding to different wiring positions of the current transformer can be measured according to the current transformer. Therefore, the problem that when the wiring of the current transformer is judged to be abnormal, a hexagonal figure is drawn manually to judge the correctness of the wiring of a secondary circuit of the current transformer, the error is large, and the reliability of the relay protection operation of the power system is low is solved. According to the method, the basic data and the measurement data of the transformer connected with the current transformer to be measured are acquired, the relative error rate of the measurement data is calculated, and whether the wiring of the current transformer is abnormal or not is judged according to the relative error rate, so that the accuracy of judging whether the wiring of the current transformer is abnormal or not is effectively improved, and the reliability of relay protection operation of a power system is improved.
Referring to fig. 3, fig. 3 is a block diagram of a current transformer abnormality checking system according to a third embodiment of the present invention.
The invention provides a current transformer abnormity checking system, which comprises:
the data acquisition module 301 is configured to receive a current transformer check request, and acquire basic data and measurement data of a transformer to be measured;
the obtaining module 302 is configured to determine calibration data corresponding to the current transformer calibration request according to the basic data and the measurement data;
an automatic calculation module 303, configured to calculate a relative error rate of the measurement data;
the judging module 304 is used for judging whether the wiring of the current transformer is abnormal or not according to the relative error rate;
and the analysis module 305 is configured to determine a wiring abnormal position of the current transformer based on the measurement data if it is determined that the wiring of the current transformer is abnormal.
Optionally, the data acquisition module 301 is specifically configured to:
receiving a current transformer checking request, connecting the output end of a preset transformer short-circuit test device to the high-voltage side of a transformer to be tested, and connecting the input end of the transformer short-circuit test device to a mains supply three-phase socket to form a transformer short-circuit test loop and conduct the transformer short-circuit test loop;
acquiring measurement data of a transformer to be measured through a transformer test device;
and acquiring basic data of the transformer to be tested.
Optionally, the obtaining module 302 is specifically configured to:
substituting the basic data and the measurement data into a high-voltage side primary current calculation formula to calculate a high-voltage side primary current theoretical value;
the high-voltage side primary current calculation formula is specifically as follows:
wherein,XT is the transformer impedance, U is the interphase voltage at the high-voltage side of the transformer, ud% is the short-circuit impedance, S e Rated capacity of transformer, U he At a high pressureSide rated voltage, I h1 Is a theoretical value of primary current at a high-voltage side;
and calculating the ratio of the high-voltage side primary current theoretical value to the high-voltage side current transformer transformation ratio to obtain a high-voltage side secondary current theoretical value.
Optionally, the automatic calculation module 303 is specifically configured to:
calculating a first difference value between the high-voltage side three-phase and a high-voltage side three-phase theoretical value, and determining the ratio of the first difference value to the high-voltage side three-phase theoretical value as a first relative error rate;
calculating a second difference value between the low-voltage side three-phase and the low-voltage side three-phase theoretical value, and determining the ratio of the second difference value to the low-voltage side three-phase theoretical value as a second relative error rate;
and calculating a third difference value between the high-voltage side secondary current and the theoretical value of the high-voltage side secondary current, and determining the ratio of the third difference value to the theoretical value of the high-voltage side secondary current as a third phase error rate.
The determining module 304 is specifically configured to:
judging whether the current transformer is a differential winding current transformer or not, and if the current transformer is the differential winding current transformer, comparing whether a differential current sampling value is less than or equal to a preset differential current threshold value or not;
if not, judging that the current transformer is abnormal in wiring;
if yes, judging whether the first relative error rate is equal to a preset phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal;
if the current transformer is other current transformers, judging whether the current transformer is a low-voltage side current transformer;
if the current transformer is a low-voltage side current transformer, judging whether the second relative error rate is equal to a preset phase difference threshold value or not;
if the second relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
if the second relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal;
if the current transformer is not the low-voltage side current transformer, judging whether the first relative error rate is equal to a phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
and if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal.
The analysis module is specifically configured to:
acquiring measurement data of abnormal wiring of the output current transformer;
if the abnormal measurement data is the differential flow sampling value, judging that the differential winding current transformer is abnormal;
if the abnormal measurement data is the high-voltage side three-phase, judging that the current transformer pointing to the main transformer is abnormal;
and if the abnormal measurement data is the low-voltage side three-phase, judging that the pointing bus current transformer is abnormal.
An electronic device according to an embodiment of the present invention includes: a memory 401 and a processor 402, the memory 402 storing a computer program; the computer program, when executed by the processor 402, causes the processor 402 to perform the current transformer abnormality checking method of any of the embodiments described above.
The memory 401 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read only memory), an EPROM, a hard disk, or a ROM. The memory 401 has a storage space 403 for program code 413 for performing any of the method steps of the above-described method. For example, the storage space 403 for the program code may comprise respective program codes 413 for implementing respective steps in the above method, respectively. The program code can be read from and written to one or more computer program products. These computer program products comprise a program code carrier such as a hard disk, a Compact Disc (CD), a memory card or a floppy disk. The program code may be compressed, for example, in a suitable form. The code, when executed by a computing processing device, causes the computing processing device to perform the steps of the method described above.
Embodiments of the present invention provide a computer-readable storage medium, on which a computer program is stored, where when the computer program is executed, the method for checking the abnormality of a current transformer according to any embodiment of the present invention is implemented.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit 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 embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should 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 current transformer abnormity checking method is characterized by relating to a transformer to be tested, wherein the transformer to be tested is connected with a current transformer; the method comprises the following steps:
responding to a current transformer checking request, and collecting basic data and measurement data of the transformer to be measured;
determining verification data corresponding to the current transformer verification request according to the basic data and the measurement data;
calculating a relative error rate of the measurement data;
judging whether the wiring of the current transformer is abnormal or not according to the relative error rate and the type of the current transformer;
and if the wiring of the current transformer is judged to be abnormal, determining the abnormal wiring position of the current transformer based on the measurement data.
2. The method for checking the abnormality of the current transformer according to claim 1, wherein the step of collecting the basic data and the measurement data of the transformer to be tested in response to the request for checking the current transformer includes:
responding to a current transformer checking request, connecting an output end of a preset transformer short-circuit test device to a high-voltage side of the transformer to be tested, and connecting an input end of the transformer short-circuit test device to a mains supply three-phase socket to form a transformer short-circuit test loop and conduct the transformer short-circuit test loop;
acquiring measurement data of the transformer to be tested through the transformer test device; the measurement data comprises a high-voltage side primary current, a high-voltage side secondary current, a differential current sampling value of a differential protection device, a high-voltage side three-phase and a low-voltage side three-phase;
acquiring basic data of the transformer to be tested; the basic data comprises rated capacity of the transformer, rated voltage of a high-voltage side, short-circuit impedance, transformation ratio of a current transformer at the high-voltage side and interphase voltage of the high-voltage side of the transformer.
3. The current transformer abnormality checking method according to claim 1, wherein the checking data includes a high-side primary current theoretical value and a high-side secondary current theoretical value; the step of determining the verification data corresponding to the current transformer verification request according to the basic data and the measurement data includes:
substituting the basic data and the measurement data into a high-voltage side primary current calculation formula to calculate a high-voltage side primary current theoretical value;
the high-voltage side primary current calculation formula is specifically as follows:
wherein,X T is the transformer impedance, U is the interphase voltage on the high-voltage side of the transformer, U d % is short-circuit impedance, S e Rated capacity, U, of the transformer he For the high-side voltage rating, I h1 Is a theoretical value of primary current at a high-voltage side;
and calculating the ratio of the high-voltage side primary current theoretical value to the high-voltage side current transformer transformation ratio to obtain a high-voltage side secondary current theoretical value.
4. The current transformer abnormality checking method according to claim 3, wherein said step of calculating a relative error rate of said measurement data includes:
calculating a first difference value of the high-voltage side three-phase and a high-voltage side three-phase theoretical value, and determining the ratio of the first difference value to the high-voltage side three-phase theoretical value as a first relative error rate;
calculating a second difference value of the low-voltage side three-phase and the low-voltage side three-phase theoretical value, and determining the ratio of the second difference value to the low-voltage side three-phase theoretical value as a second relative error rate;
and calculating a third difference value of the high-voltage side secondary current and the theoretical value of the high-voltage side secondary current, and determining the ratio of the third difference value to the theoretical value of the high-voltage side secondary current as a third phase error rate.
5. The method for checking the abnormality of a current transformer according to claim 4, wherein when the current transformer is a differential winding current transformer, the step of determining whether there is an abnormality in the connection of the current transformer based on the relative error rate and the type of the current transformer includes:
comparing whether the difference flow sampling value is less than or equal to a preset difference flow threshold value or not;
if not, judging that the current transformer is abnormal in wiring;
if yes, judging whether the first relative error rate is equal to a preset phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the current transformer is normal in wiring;
and if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal.
6. The method for checking the abnormality of a current transformer according to claim 4, wherein when the current transformer is another current transformer, the step of determining whether the wiring of the current transformer is abnormal or not according to the relative error rate and the type of the current transformer includes:
judging whether the current transformer is a low-voltage side current transformer or not;
if the current transformer is the low-voltage side current transformer, judging whether the second relative error rate is equal to a preset phase difference threshold value or not;
if the second relative error rate is equal to the phase difference threshold value, judging that the current transformer is normal in wiring;
if the second relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal;
if the current transformer is not the low-voltage side current transformer, judging whether the first relative error rate is equal to a phase difference threshold value or not;
if the first relative error rate is equal to the phase difference threshold value, judging that the wiring of the current transformer is normal;
and if the first relative error rate is not equal to the phase difference threshold value, judging that the wiring of the current transformer is abnormal.
7. The method for checking the abnormality of the current transformer according to claim 4, further comprising:
judging whether the third phase error rate is larger than a preset high-voltage current threshold value or not;
if so, judging that the current transformer has a fault;
if not, judging that the current transformer is normal.
8. A current transformer abnormity calibration system is characterized by relating to a transformer to be tested, wherein the transformer to be tested is connected with a current transformer; the system comprises:
the data acquisition module is used for receiving a current transformer check request and acquiring basic data and measurement data of the transformer to be measured;
the acquisition module is used for determining verification data corresponding to the current transformer verification request according to the basic data and the measurement data;
an automatic calculation module for calculating a relative error rate of the measurement data;
the judging module is used for judging whether the wiring of the current transformer is abnormal or not according to the relative error rate and the type of the current transformer;
and the analysis module is used for determining the abnormal wiring position of the current transformer based on the measurement data if the abnormal wiring of the current transformer is judged.
9. An electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer program, when executed by the processor, causes the processor to perform the steps of the current transformer abnormality checking method according to any one of claims 1 to 7.
10. A computer-readable storage medium having stored thereon a computer program, wherein the computer program when executed implements a current transformer abnormality checking method according to any one of claims 1 to 7.
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Cited By (2)
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CN116125183A (en) * | 2023-04-20 | 2023-05-16 | 南京先正科技有限公司 | Resistor on-line fault diagnosis method and system based on safe production |
CN117949886A (en) * | 2024-03-27 | 2024-04-30 | 国网山西省电力公司营销服务中心 | Intelligent regulation and control method and system for transformer calibrator, electronic equipment and storage medium |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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CN116125183A (en) * | 2023-04-20 | 2023-05-16 | 南京先正科技有限公司 | Resistor on-line fault diagnosis method and system based on safe production |
CN116125183B (en) * | 2023-04-20 | 2023-06-30 | 南京先正科技有限公司 | Resistor on-line fault diagnosis method and system based on safe production |
CN117949886A (en) * | 2024-03-27 | 2024-04-30 | 国网山西省电力公司营销服务中心 | Intelligent regulation and control method and system for transformer calibrator, electronic equipment and storage medium |
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