CN111654008A - Temporary zero-sequence overcurrent protection engineering setting method and system for transformer - Google Patents
Temporary zero-sequence overcurrent protection engineering setting method and system for transformer Download PDFInfo
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- CN111654008A CN111654008A CN202010515999.9A CN202010515999A CN111654008A CN 111654008 A CN111654008 A CN 111654008A CN 202010515999 A CN202010515999 A CN 202010515999A CN 111654008 A CN111654008 A CN 111654008A
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- transformer
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- overcurrent protection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
Abstract
The invention belongs to the related field of safe operation protection of a power grid system and discloses a temporary zero sequence overcurrent protection engineering setting method for a transformer, which comprises the following steps: carrying out primary switching on a transformer to be started, and measuring three-phase current flowing through a high-voltage side of the transformer and adjacent elements; calculating the zero-mode inrush current and zero-sequence current effective values flowing through the high-voltage side and the adjacent elements of the transformer; solving the corresponding zero sequence current effective value peak value, and calculating the ratio of the two values as a proportionality coefficient; based on the proportional coefficient, the action threshold value and the related action delay for realizing the temporary zero sequence protection when the transformer is started and put into operation are calculated. The invention also discloses a corresponding setting system, a computer readable storage medium and a terminal. The invention can effectively solve the problem of the false operation of the zero sequence overcurrent protection of the adjacent elements during the air drop of the transformer without acquiring the electrical parameters of any transformer and the adjacent elements, and has the characteristics of simplicity, reliability, easy operation, strong applicability and the like.
Description
Technical Field
The invention belongs to the field related to the safe operation protection of a power grid system, and particularly relates to a temporary zero-sequence overcurrent protection engineering setting method and system for a transformer.
Background
In recent years, various high-short-circuit impedance transformers are widely applied, and the condition of zero sequence overcurrent protection misoperation of adjacent elements (such as circuits) during multiple transformer operation appears, thereby bringing serious threat to the safe operation of a system. In engineering practice, line zero sequence overcurrent protection is usually performed on the principle of ensuring sufficient sensitivity for both line end ground faults and also for faults passing through maximum transition resistance. When the transformer is put into operation, three-phase unbalanced excitation inrush current can be generated, and zero sequence current with certain magnitude is correspondingly formed. The magnetizing inrush current is not a fault when the transformer is put into operation, and zero sequence overcurrent protection of the circuit should not act. Therefore, it is necessary to provide a method for preventing the malfunction of the adjacent elements when the transformer is put into operation.
More specifically, the failure of the transformer is not a serious accident, but the protection of adjacent elements such as lines is misoperated due to the transformer operation, which greatly affects the reliability of power supply. Under the condition, if the zero sequence overcurrent protection of the circuit is enabled to act in a scene, the zero sequence overcurrent protection of the transformer acts in advance, and the high-voltage side circuit breaker is tripped, so that the damage to the system is reduced. Therefore, the temporary zero-sequence overcurrent protection can be configured for the transformer, so that the zero-sequence overcurrent protection of the transformer acts first in the scene of the zero-sequence overcurrent protection action of the adjacent element. However, further research finds that the setting of zero-sequence overcurrent protection of the transformer in the prior art is generally only matched with the first section or the second section or the backup section of the zero-sequence overcurrent protection of the adjacent line, and does not have a perfect temporary protection function. Accordingly, how to develop a simple, reliable and easy-to-operate temporary zero-sequence overcurrent engineering setting method is becoming one of the technical problems to be solved urgently in the field.
Disclosure of Invention
Aiming at the defects or technical requirements in the prior art, the invention aims to provide a setting method and a setting system for temporary zero-sequence overcurrent protection engineering of a transformer, wherein the whole setting process is redesigned, and targeted improvements are made on a plurality of aspects such as key operation steps, temporary protection mechanisms and the like, so that the problem of the false operation of the zero-sequence overcurrent protection of adjacent elements during the air-drop of the transformer can be effectively solved without acquiring the electric parameters of any transformer and the adjacent elements, and the setting method and the setting system have the characteristics of simplicity, reliability, easy operation, strong applicability and the like, so that the setting method and the setting system are particularly suitable for application occasions of various high-short-circuit impedance transformers in a power grid system.
In order to achieve the above object, according to a first aspect of the present invention, there is provided a transformer temporary zero sequence overcurrent protection engineering setting method, which is characterized in that the method includes:
s101, performing primary closing on a transformer to be started, and measuring and recording three-phase currents flowing through a high-voltage side of the transformer and adjacent elements respectively;
s102, respectively calculating zero-mode inrush currents flowing through a high-voltage side and adjacent elements of the transformer based on three-phase current data obtained through measurement, and then obtaining corresponding zero-sequence current effective values through Fourier transform;
s103, solving the zero sequence current effective value peak values of the high-voltage side of the transformer and the adjacent elements, and then calculating the ratio of the two values as a proportionality coefficient;
s104, multiplying the calculated proportionality coefficient by a preset zero sequence overcurrent protection action threshold value of adjacent elements and a preset reliability coefficient in sequence to correspondingly obtain a required action threshold value capable of realizing temporary zero sequence protection when the transformer is started and put into operation; meanwhile, the reliable coefficient is multiplied by the preset time delay to correspondingly obtain the action time delay required by the realization of the temporary zero sequence protection when the transformer is started and put into operation, thereby completing the whole setting process of the temporary zero sequence overcurrent protection engineering of the transformer.
Further preferably, the reliability coefficient is preferably set to 0.95.
As a further preference, the transformer is preferably a high short-circuit impedance transformer in a power grid system.
According to a second aspect of the present invention, there is provided a transformer temporary zero sequence overcurrent protection engineering setting system, which is characterized in that the system includes:
the system comprises a data acquisition module, a data acquisition module and a control module, wherein the data acquisition module is used for acquiring three-phase current data flowing through a high-voltage side of a transformer to be started and adjacent elements in real time after the transformer to be started is subjected to initial switching-on;
the first calculation module is used for extracting three-phase current data of the data acquisition module, respectively calculating zero-mode inrush currents flowing through a high-voltage side and adjacent elements of the transformer, and then obtaining corresponding zero-sequence current effective values through Fourier transform;
the second calculation module is used for extracting the zero sequence current effective value of the first calculation module, then solving the zero sequence current effective value peak values of the high-voltage side of the transformer and the adjacent elements, and then calculating the ratio of the two effective value peak values as a proportionality coefficient;
the third calculation module is used for extracting the proportionality coefficient of the second calculation module, and then sequentially multiplying the proportionality coefficient by a preset zero sequence overcurrent protection action threshold value of adjacent elements and a preset reliability coefficient to correspondingly obtain a required action threshold value capable of realizing temporary zero sequence protection when the transformer is started and put into operation; meanwhile, multiplying the reliable coefficient by a preset delay to correspondingly obtain the action delay required by the temporary zero sequence protection when the transformer is started and put into operation;
and the setting module executes temporary zero-sequence overcurrent protection engineering setting on the transformer based on the required action threshold value and the required action delay obtained by the third calculation module so as to solve the problem of the misoperation of the zero-sequence overcurrent protection of adjacent elements during the air-drop of the decompressor.
According to a third aspect of the present invention, a computer-readable storage medium is further provided, which is characterized in that a computer program for implementing the transformer temporary zero-sequence overcurrent protection engineering setting method is stored in the computer-readable storage medium.
According to a fourth aspect of the present invention, there is further provided a transformer temporary zero sequence overcurrent protection engineering tuning terminal, which is characterized by comprising a memory and a processor, wherein the memory stores therein a computer program for implementing the tuning method, and the processor is configured to invoke the computer program in the memory to implement a corresponding tuning process.
Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:
(1) the invention redesigns the whole setting process of the temporary zero-sequence overcurrent protection, improves a plurality of aspects such as key operation steps, a temporary protection mechanism and the like in a targeted manner, and accordingly can effectively solve the problem of the false operation of the zero-sequence overcurrent protection of the adjacent elements during the air-drop of the transformer under the condition of not acquiring the electrical parameters of any transformer and the adjacent elements;
(2) the setting method and the system can resist noise interference to a certain degree, and have the characteristics of simplicity, reliability, easy operation, strong applicability and the like, so the method and the system are particularly suitable for application occasions of various high short-circuit impedance transformers in a power grid system, and have important significance for reducing the safe and stable operation risk brought to the power grid system by starting and operating the transformers.
Drawings
FIG. 1 is an overall process flow diagram of a setting method of a temporary zero-sequence over-current protection project of a transformer constructed according to the invention;
FIG. 2 is a schematic diagram for exemplary illustration of a typical application scenario of a tuning process according to the present invention;
FIG. 3 is a schematic diagram of measuring three-phase current flowing through the high-voltage side after the transformer in FIG. 2 is subjected to initial no-load closing;
FIG. 4 is a schematic diagram of a three-phase current measurement through adjacent components after an initial no-load closing of the transformer of FIG. 2;
FIG. 5 is a schematic diagram of the zero mode inrush current of the transformer and the line obtained by the continuous calculation according to the invention;
fig. 6 is a schematic diagram of effective values of zero sequence currents of the transformer and the line obtained by continuous calculation according to the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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.
Fig. 2 is a schematic diagram for exemplary illustration of an application scenario of the tuning process according to the present invention.
First, as shown in fig. 2, according to the present invention, the #2 transformer to be started can be subjected to initial no-load closing while performing recording. Three-phase currents flowing through the high-voltage side of the #2 transformer and the #1 line were measured. The three-phase current recorded correspondingly can be specifically shown in fig. 3 and 4, and can be recorded as iA、iB、iCAnd iA1、iB1、iC1。
And then, based on the three-phase current data obtained by measurement, respectively calculating zero-mode inrush currents flowing through the high-voltage side of the transformer and adjacent elements, and then obtaining the zero-sequence current effective values corresponding to the zero-mode inrush currents through Fourier transform.
More specifically, the measured data can be used to calculate the zero mode inrush current (3 i) flowing through the high-voltage side of the #2 transformer, for example0＝iA+iB+iC) And Fourier computing zero sequence current effective value 3I0(ii) a Calculating current through #1 lineZero mode inrush current (3 i)01＝iA1+iB1+iC1) And Fourier computing zero sequence current effective value 3I01. The zero mode inrush current and zero sequence current effective values of the #2 transformer and the line are shown in fig. 5 and 6.
Then, the zero sequence current effective value peak values of the high-voltage side of the transformer and the adjacent elements are obtained, and then the ratio of the two is calculated and used as a proportionality coefficient.
More specifically, for example, the peak value "3I" of the zero-sequence current effective value on the high-voltage side of the transformer can be obtained0(p)'Peak value of zero sequence current effective value of adjacent element' 3I01(p)", and calculating the ratio of the two as the proportionality coefficient KI0＝3I0(p)/3I01(p)。
Finally, multiplying the calculated proportionality coefficient by a preset zero sequence overcurrent protection action threshold value of adjacent elements and a preset reliability coefficient in sequence to correspondingly obtain a required action threshold value capable of realizing temporary zero sequence protection when the transformer is started and put into operation; meanwhile, the reliable coefficient is multiplied by the preset time delay to correspondingly obtain the action time delay required by the realization of the temporary zero sequence protection when the transformer is started and put into operation, thereby completing the whole setting process of the temporary zero sequence overcurrent protection engineering of the transformer.
More specifically, for example, the threshold value and the time delay of zero-sequence overcurrent protection action of adjacent elements can be preset to be 3I respectively01setAnd tset1. Multiplying the threshold value by the scaling factor KI0And a reliability factor KrelThen obtaining the action threshold value 3I of the temporary zero sequence protection when the transformer is started and put into operation0setDelay times a reliability factor KrelObtaining action time delay t of temporary zero sequence protectionsetI.e. 3I0set＝KI0*Krel*3I01set，tset＝Krel*tset1. The reliability factor is preferably 0.95 in the present invention.
In the exemplary application scenario of fig. 2, for example, the zero sequence overcurrent protection threshold of the adjacent line may be 3I01set240A, delay time tset13s, multiplied by a scaling factor KI0And a reliability factor KrelThen obtaining the action threshold value 3I of the temporary zero sequence protection when the #2 transformer is started and put into operation0setAnd a delay tsetHere, the reliability factor is generally 0.95. 3I0set＝KI0*Krel*3I01set＝268A，tset＝Krel*tset1＝2.85s。
In conclusion, according to the invention, the problem of the false operation of the zero sequence overcurrent protection of the adjacent elements during the air drop of the transformer can be effectively solved under the condition that the electric parameters of the transformer and the adjacent elements are not required to be acquired; and the method also has the characteristics of simplicity, reliability, easy operation, strong applicability and the like, thereby being particularly suitable for various application occasions of high short-circuit impedance transformers in a power grid system.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (6)
1. A transformer temporary zero sequence overcurrent protection engineering setting method is characterized by comprising the following steps:
s101, performing primary closing on a transformer to be started, and measuring and recording three-phase currents flowing through a high-voltage side of the transformer and adjacent elements respectively;
s102, respectively calculating zero-mode inrush currents flowing through a high-voltage side and adjacent elements of the transformer based on three-phase current data obtained through measurement, and then obtaining corresponding zero-sequence current effective values through Fourier transform;
s103, solving the zero sequence current effective value peak values of the high-voltage side of the transformer and the adjacent elements, and then calculating the ratio of the two values as a proportionality coefficient;
s104, multiplying the calculated proportionality coefficient by a preset zero sequence overcurrent protection action threshold value of adjacent elements and a preset reliability coefficient in sequence to correspondingly obtain a required action threshold value capable of realizing temporary zero sequence protection when the transformer is started and put into operation; meanwhile, the reliable coefficient is multiplied by the preset time delay to correspondingly obtain the action time delay required by the realization of the temporary zero sequence protection when the transformer is started and put into operation, thereby completing the whole setting process of the temporary zero sequence overcurrent protection engineering of the transformer.
2. The setting method for the temporary zero-sequence over-current protection engineering of the transformer according to claim 1, wherein the reliability coefficient is preferably set to 0.95.
3. The transformer temporary zero sequence overcurrent protection engineering setting method as set forth in claim 1 or 2, wherein the transformer is preferably a high short-circuit impedance transformer in a power grid system.
4. A transformer temporary zero sequence overcurrent protection engineering setting system is characterized by comprising:
the system comprises a data acquisition module, a data acquisition module and a control module, wherein the data acquisition module is used for acquiring three-phase current data flowing through a high-voltage side of a transformer to be started and adjacent elements in real time after the transformer to be started is subjected to initial switching-on;
the first calculation module is used for extracting three-phase current data of the data acquisition module, respectively calculating zero-mode inrush currents flowing through a high-voltage side and adjacent elements of the transformer, and then obtaining corresponding zero-sequence current effective values through Fourier transform;
the second calculation module is used for extracting the zero sequence current effective value of the first calculation module, then solving the zero sequence current effective value peak values of the high-voltage side of the transformer and the adjacent elements, and then calculating the ratio of the two effective value peak values as a proportionality coefficient;
the third calculation module is used for extracting the proportionality coefficient of the second calculation module, and then sequentially multiplying the proportionality coefficient by a preset zero sequence overcurrent protection action threshold value of adjacent elements and a preset reliability coefficient to correspondingly obtain a required action threshold value capable of realizing temporary zero sequence protection when the transformer is started and put into operation; meanwhile, multiplying the reliable coefficient by a preset delay to correspondingly obtain the action delay required by the temporary zero sequence protection when the transformer is started and put into operation;
and the setting module executes temporary zero-sequence overcurrent protection engineering setting on the transformer based on the required action threshold value and the required action delay obtained by the third calculation module so as to solve the problem of the misoperation of the zero-sequence overcurrent protection of adjacent elements during the air-drop of the decompressor.
5. A computer readable storage medium, characterized in that the computer readable storage medium has stored therein a computer program for implementing the transformer temporary zero sequence overcurrent protection engineering tuning method of claim 1.
6. A transformer temporary zero sequence overcurrent protection engineering setting terminal is characterized by comprising a memory and a processor, wherein the memory stores the computer program of claim 5, and the processor is used for calling the computer program in the memory to realize a corresponding setting process.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20030091267A (en) * | 2002-05-27 | 2003-12-03 | 엘지전선 주식회사 | Over current relay using zero-sequence current of ground wire |
| CN109119971A (en) * | 2018-09-03 | 2019-01-01 | 广东电网有限责任公司 | zero-sequence over-current protection method, system, device and computer readable storage medium |
| CN110137908A (en) * | 2019-06-13 | 2019-08-16 | 广东电网有限责任公司 | A kind of the zero-sequence over-current protection method and relevant apparatus of high-impedance transformer |
| CN110265972A (en) * | 2019-06-14 | 2019-09-20 | 华中科技大学 | A kind of zero-sequence current protection setting method |
| CN110854800A (en) * | 2019-09-29 | 2020-02-28 | 广东电网有限责任公司 | Zero-sequence over-current setting method, device and equipment |
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- 2020-06-09 CN CN202010515999.9A patent/CN111654008B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030091267A (en) * | 2002-05-27 | 2003-12-03 | 엘지전선 주식회사 | Over current relay using zero-sequence current of ground wire |
| CN109119971A (en) * | 2018-09-03 | 2019-01-01 | 广东电网有限责任公司 | zero-sequence over-current protection method, system, device and computer readable storage medium |
| CN110137908A (en) * | 2019-06-13 | 2019-08-16 | 广东电网有限责任公司 | A kind of the zero-sequence over-current protection method and relevant apparatus of high-impedance transformer |
| CN110265972A (en) * | 2019-06-14 | 2019-09-20 | 华中科技大学 | A kind of zero-sequence current protection setting method |
| CN110854800A (en) * | 2019-09-29 | 2020-02-28 | 广东电网有限责任公司 | Zero-sequence over-current setting method, device and equipment |
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