CN111521951B - Method and device for preventing misjudgment of CT (current transformer) broken line caused by grounding fault of control winding side of valve-controlled reactor and storage medium - Google Patents
Method and device for preventing misjudgment of CT (current transformer) broken line caused by grounding fault of control winding side of valve-controlled reactor and storage medium Download PDFInfo
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- CN111521951B CN111521951B CN202010289459.3A CN202010289459A CN111521951B CN 111521951 B CN111521951 B CN 111521951B CN 202010289459 A CN202010289459 A CN 202010289459A CN 111521951 B CN111521951 B CN 111521951B
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/72—Testing of electric windings
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The invention discloses a method, a device and a storage medium for preventing a CT (current transformer) line break from being misjudged by a ground fault on the control winding side of a valve-controlled reactor, and aims to solve the technical problem that the large-difference protection operation rejection is caused because the CT line break is easily misjudged by the ground fault on the control winding side of the valve-controlled reactor. It includes: performing preliminary judgment on CT disconnection at the control winding side of the valve-controlled reactor based on CT disconnection judgment logic; further judging the preliminary judgment result based on the logic for preventing CT wire breakage misjudgment, and determining whether CT wire breakage occurs on the control winding side of the valve control type reactor; and judging the CT disconnection return on the control winding side based on the CT disconnection return judging logic, and controlling the CT disconnection mark to return according to the judgment result. The invention can accurately judge whether the CT disconnection fault occurs on the control winding side of the valve-controlled reactor, avoids the occurrence of rejection of large-difference main protection of the valve-controlled reactor caused by misjudgment, and effectively improves the sensitivity and reliability of protection.
Description
Technical Field
The invention relates to a method and a device for preventing a CT (current transformer) line breaking caused by a side grounding fault of a control winding of a valve-controlled reactor, and a storage medium, and belongs to the technical field of power system analysis.
Background
The shunt reactor has the functions of limiting overvoltage and reactive compensation, the shunt reactor can be divided into a fixed-capacity reactor and an adjustable-capacity shunt reactor, the valve-controlled graded controllable reactor is the adjustable-capacity shunt reactor, the capacity of the fixed-capacity reactor is not adjustable, the capacity of the valve-controlled graded controllable shunt reactor can be regulated in a grading mode, dynamic regulation can be carried out according to the reactive power requirement of the system, and therefore the shunt reactor is widely used in an extra-high voltage power system.
In order to reliably protect the valve-controlled hierarchical controllable shunt reactor, a power system is provided with reliable large-difference protection as main protection, but because of the characteristics of the reactor, the leakage reactance of the reactor is basically more than 95%, when the secondary side (namely the control winding side) of the valve-controlled hierarchical controllable shunt reactor has an internal grounding fault, the voltage of the reactor network side is almost unchanged, the current change is extremely small, the fault phase CT of the control winding side does not have current flow, and the protection device can be mistakenly judged as the CT disconnection of the control winding side, so that the large-difference main protection is locked, the protection is rejected, the reactor cannot normally work due to damage, and the safe and stable operation of the whole power system can be influenced in serious cases.
The reactor protection device adopted in the prior engineering can not distinguish whether the CT on the control winding side has no current and has an internal grounding fault or a CT broken line fault, and a method for preventing the CT broken line from being misjudged by the grounding fault on the control winding side of the valve control type reactor is unavailable.
Disclosure of Invention
The invention aims to overcome the defect that earth faults occurring at the control winding side of a valve-controlled reactor in the prior art are easily judged to be CT broken lines by mistake and cause large-difference protection rejection, and provides a method, a device and a storage medium for preventing earth faults at the control winding side of the valve-controlled reactor from judging the CT broken lines by mistake.
In order to achieve the purpose, the invention is realized by adopting the following technical scheme:
in a first aspect, the invention provides a method for preventing misjudgment of a CT line fault caused by a grounding fault at a control winding side of a valve-controlled reactor, which specifically comprises the following steps:
performing preliminary judgment on CT disconnection at the control winding side of the valve control type reactor based on CT disconnection judgment logic;
further judging the preliminary judgment result based on the CT wire breakage misjudgment prevention logic, and determining whether CT wire breakage occurs on the control winding side of the valve control type reactor;
and after CT disconnection occurs at the control winding side, judging the CT disconnection return at the control winding side based on the CT disconnection return judging logic, and controlling the CT disconnection mark to return according to the judgment result.
Further, the preliminary judgment method includes the following steps:
setting a plurality of CT disconnection judging conditions, and preliminarily judging that CT disconnection occurs on the control winding side when the current of the neutral point CT on the control winding side of the valve control type reactor meets all the CT disconnection judging conditions; otherwise, preliminarily judging that the CT wire breakage does not occur on the control winding side;
the CT broken line judging conditions comprise that zero sequence current exists at the CT broken line side, differential current exists at the CT broken line phase, the reduction value of the voltage at the CT broken line side is less than 5V within 5ms, and no current exists at the CT broken line phase.
Further, the method for determining whether CT disconnection occurs on the control winding side of the valve-controlled reactor comprises the following steps:
when the CT disconnection at the control winding side is preliminarily judged and the CT current at the neutral point at the control winding side meets the condition of preventing the CT disconnection from being judged by mistake, the internal grounding fault of the control winding side generation area is judged, the CT disconnection judging logic is locked, and the CT disconnection from being judged by mistake is prevented; when the CT disconnection at the control winding side is preliminarily judged and the CT current at the neutral point at the control winding side does not meet the condition for preventing the CT disconnection from being judged by mistake, the CT disconnection at the control winding side is judged;
the condition for preventing CT disconnection misjudgment comprises that current flows through a neutral point CT on the control winding side.
Further, the condition that the current flows through the control winding side neutral point CT is judged to be that the current of the control winding side neutral point CT is larger than a threshold value.
Further, the threshold value is 0.05 times of the CT secondary rated current value.
Further, the method for judging the CT disconnection return on the control winding side based on the CT disconnection return judging logic comprises the following steps:
setting a plurality of CT broken line return judging conditions, controlling the CT broken line to return when the current on the control winding side of the valve control type reactor meets any one CT broken line return judging condition, and controlling the CT broken line not to return when the current on the control winding side does not meet all CT broken line return judging conditions;
the CT broken wire return judging conditions comprise no zero sequence current, three-phase current or three-phase no current.
In a second aspect, the present invention provides an apparatus for preventing misjudgment of a CT line fault due to a ground fault on a control winding side of a valve-controlled reactor, comprising:
the voltage and current sensor is used for collecting voltage and current at the broken line side of the CT;
the CT disconnection judging module is used for preliminarily judging the CT disconnection at the control winding side of the valve control type reactor based on the CT disconnection judging logic according to the acquired voltage and current at the CT disconnection side;
the CT wire breakage misjudgment preventing module is used for further judging the preliminary judgment result of the CT wire breakage judging module according to the CT wire breakage misjudgment preventing logic and determining whether the CT wire breakage occurs on the control winding side of the valve control type reactor;
and the CT disconnection return judging module is used for judging the CT disconnection return of the control winding side according to the CT disconnection return judging logic after the CT disconnection occurs at the control winding side, and controlling the CT disconnection mark to return according to the judging result.
In a third aspect, the invention provides a device for preventing misjudgment of a CT broken line caused by a ground fault at a control winding side of a valve-controlled reactor, which comprises a processor and a storage medium, wherein the processor is used for processing a signal of a CT broken line; the storage medium is to store instructions; the processor is used for operating according to the instruction to execute the steps of the method for preventing the misjudgment of the CT broken line caused by the ground fault of the control winding side of the valve-controlled reactor.
In a fourth aspect, the present invention provides a computer readable storage medium, having stored thereon a computer program, which when executed by a processor, implements the steps of the aforementioned method for preventing a fault on the control winding side ground of a valve-regulated reactor from misjudging a CT break line.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a method, a device and a storage medium for preventing ground fault misjudgment of a CT (current transformer) broken line of a control winding side of a valve-controlled reactor, which are used for carrying out preliminary CT broken line judgment based on CT broken line judgment logic, then further judging a preliminary judgment result by the CT broken line misjudgment prevention logic to prevent CT broken line misjudgment, further preventing the occurrence of large-difference main protection rejection of the valve-controlled reactor, and improving the sensitivity and the reliability of reactor protection. In addition, the invention provides independent CT broken wire return judging logic to judge CT broken wire return, can effectively avoid CT broken wire return misjudgment, and can avoid the problem of large-difference main protection maloperation caused by misjudgment of CT broken wire return when the control winding side generates external grounding fault again after CT broken wire occurs on the control winding side.
The logic for preventing CT wire breakage of the invention utilizes the characteristic that when a valve-controlled reactor controls the winding side to generate ground fault, the current of the neutral point CT at the control winding side can flow through, and when the CT wire breakage occurs at the control winding side, the neutral point CT at the control winding side can not flow through, the detection that the current of the neutral point CT at the control winding side exists or does not exist is introduced into a basic field of the conventional CT wire breakage judgment, the CT wire breakage judgment at the control winding side is corrected and supplemented, when the CT wire breakage judgment condition is satisfied at the control winding side and the current of the neutral point CT does not exist at the control winding side, otherwise, the CT wire breakage is judged to be the grounding fault in the area, the CT wire breakage judgment logic is locked, the CT wire breakage misjudgment is prevented, and compared with the prior art, the CT wire breakage judgment of the invention is more accurate and reliable. Meanwhile, in order to avoid the influence of the error of the transformer on the judgment of the current and no-current of the control winding side neutral point CT, the invention introduces the current judgment threshold value of the control winding neutral point CT, thereby further improving the reliability of protection.
Drawings
Fig. 1 is a schematic step flow diagram of a method for preventing a fault of grounding at a control winding side of a valve-controlled reactor from misjudging a CT broken line according to an embodiment of the present invention.
FIG. 2 is a logic diagram for judging CT disconnection according to an embodiment of the present invention.
FIG. 3 is a logic diagram for preventing CT wire breakage misjudgment according to an embodiment of the present invention.
FIG. 4 is a CT wire break return decision logic diagram according to an embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a device for preventing misjudgment of a CT line fault due to a ground fault on a control winding side of a valve-controlled reactor according to an embodiment of the present invention.
In the figure: the device comprises a voltage and current sensor 1, a CT broken line judgment module 2, a CT broken line error judgment module 3 and a CT broken line return judgment module 4.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
The embodiment of the invention provides a method for preventing misjudgment of a CT (current transformer) broken line caused by a grounding fault at a control winding side of a valve-controlled reactor, as shown in figure 1, the method specifically comprises the following steps:
the method comprises the following steps of preliminarily judging CT disconnection at the control winding side of the valve-controlled reactor based on CT disconnection judging logic, specifically: setting a plurality of CT disconnection judging conditions, and preliminarily judging that CT disconnection occurs on the control winding side when the current of the neutral point CT on the control winding side of the valve control type reactor meets all the CT disconnection judging conditions; otherwise, the CT disconnection on the control winding side is preliminarily judged. Fig. 2 is a CT disconnection judging logic diagram of the method of the present invention, wherein the CT disconnection judging conditions include that there is zero sequence current at the CT disconnection side, there is a difference current at the CT disconnection phase, the voltage drop value at the CT disconnection side is less than 5V within 5ms, and there is no current at the CT disconnection phase, and when the CT current at the neutral point of the control winding side simultaneously satisfies the four CT disconnection judging conditions, it is preliminarily judged that the CT disconnection occurs at the control winding side.
And further judging the preliminary judgment result based on the logic for preventing CT wire breakage misjudgment, and determining whether the CT wire breakage occurs on the control winding side of the valve control type reactor.
When the control winding side of the valve-controlled controllable shunt reactor has an internal grounding fault, the voltage of the reactor network side is almost unchanged, the current change is extremely small, the fault phase CT of the control winding side has no current flow, and the protection device is similar to the line breaking characteristic of a CT secondary circuit. As shown in fig. 3, the specific contents of the logic for preventing CT disconnection misjudgment are as follows: when the CT disconnection at the control winding side is preliminarily judged and the CT current at the neutral point at the control winding side meets the condition of preventing the CT disconnection from being judged by mistake, the internal grounding fault of the control winding side generation area is judged, the CT disconnection judging logic is locked, and the CT disconnection from being judged by mistake is prevented; and when the CT wire breakage on the control winding side is preliminarily judged and the CT current of the neutral point on the control winding side does not meet the condition for preventing the CT wire breakage misjudgment, the CT wire breakage on the control winding side is judged.
The capacity-adjustable valve-controlled hierarchical controllable shunt reactor has the characteristics that when the control winding side has a ground fault, the control winding side neutral point CT can have current flowing through, and when the control winding side has a CT disconnection, the control winding side neutral point CT can not have current flowing through, so the invention takes the control winding side neutral point CT having current flowing through as a condition for preventing CT disconnection misjudgment to assist in judging whether the control winding side has a regional ground fault or a CT disconnection. In addition, in order to avoid that the judgment of the current existence and non-current of the control winding neutral point CT is possibly influenced by the error of the current transformer, and further the judgment of the fault and the CT broken line in the control winding area is influenced, the method also introduces a current existence judgment threshold value of the control winding neutral point CT, and the condition that the current flows through the control winding side neutral point CT is judged to be that the current of the control winding side neutral point CT is larger than the threshold value. When the current of the control winding side neutral point CT is larger than the threshold value, the control winding side neutral point CT is judged to have current, and then the control winding side occurrence area is judged to have grounding fault, otherwise, CT disconnection occurs.
The current judging threshold value of the CT of the neutral point of the control winding can be set according to the error of the primary transformer and the measuring error of the protective device, and in the embodiment of the invention, the secondary rated current value of the CT with the threshold value of 0.05 times is set. The utility and the reliability of the CT broken line judgment can be effectively improved by utilizing the logic with the threshold value for preventing the CT broken line from misjudging to judge the CT broken line.
And after CT disconnection occurs at the control winding side, judging the CT disconnection return at the control winding side based on the CT disconnection return judging logic, and controlling the CT disconnection mark to return according to the judgment result.
After the CT disconnection occurs at the control winding side, if the external ground fault occurs again at the control winding side, the CT disconnection misjudgment prevention logic may determine that the control winding side meets the locked CT disconnection judgment logic, which causes the CT disconnection flag to return, thereby misopening the amplification difference protection and causing the large difference protection to malfunction, and in order to avoid the large difference protection malfunction, the method of the present invention adopts the CT disconnection return judgment logic independent of the CT disconnection judgment logic and the CT disconnection misjudgment prevention logic to perform the CT disconnection return judgment, as shown in fig. 4, specifically: and setting a plurality of CT broken line return judging conditions, controlling the CT broken line to return when the current on the control winding side of the valve control type reactor meets any one CT broken line return judging condition, and controlling the CT broken line not to return when the current on the control winding side does not meet all CT broken line return judging conditions. The CT broken wire return judging conditions comprise no zero sequence current, three-phase current or three-phase current.
The embodiment of the invention also provides a device for preventing misjudgment of CT broken lines caused by ground faults on the control winding side of the valve-controlled reactor, which comprises a voltage and current sensor 1, a CT broken line judgment module 2, a CT broken line misjudgment prevention module 3 and a CT broken line return judgment module 4, wherein the voltage and current sensor is used for collecting voltage and current on the CT broken line side; the CT disconnection judging module is used for preliminarily judging the CT disconnection at the control winding side of the valve control type reactor based on CT disconnection judging logic according to the acquired voltage and current at the CT disconnection side; the CT wire breakage preventing misjudgment module is used for further judging the preliminary judgment result of the CT wire breakage judgment module according to the CT wire breakage preventing misjudgment logic and determining whether the CT wire breakage occurs on the control winding side of the valve control type reactor; and the CT disconnection return judging module is used for judging the CT disconnection return of the control winding side according to the CT disconnection return judging logic after the CT disconnection occurs at the control winding side, and controlling the CT disconnection mark to return according to the judging result.
The embodiment of the invention also provides a device for preventing the CT broken line misjudgment caused by the grounding fault of the control winding side of the valve-controlled reactor, which comprises a processor and a storage medium. A storage medium to store instructions; the processor is used for operating according to the instruction to execute the steps of the method for preventing the misjudgment of the CT broken line caused by the ground fault on the control winding side of the valve-controlled reactor.
Embodiments of the present invention further provide a computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the steps of the method for preventing the misjudgment of the CT line fault due to the ground fault on the control winding side of the valve-controlled reactor.
Compared with the reactor protection device and the protection method in the prior art, the method can accurately judge whether the control winding side of the valve-controlled reactor is in the generation area grounding fault or the CT disconnection fault, can accurately judge whether the CT disconnection return is carried out, avoids the occurrence of rejection of main protection due to large difference of the valve-controlled hierarchical controllable shunt reactor caused by misjudgment, effectively improves the sensitivity and the reliability of protection, and can be widely applied to the protection of the shunt reactor with adjustable capacity.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (6)
1. A method for preventing misjudgment of CT broken lines caused by grounding faults of control windings of a valve-controlled reactor is characterized by comprising the following steps:
performing preliminary judgment on CT disconnection at the control winding side of the valve-controlled reactor based on CT disconnection judgment logic;
further judging the preliminary judgment result based on the logic for preventing CT wire breakage misjudgment, and determining whether CT wire breakage occurs on the control winding side of the valve control type reactor;
after CT disconnection occurs at the control winding side, judging the CT disconnection return at the control winding side based on CT disconnection return judging logic, and controlling the CT disconnection mark to return according to the judging result;
the preliminary judgment method comprises the following steps:
setting a plurality of CT disconnection judging conditions, and preliminarily judging that CT disconnection occurs on the control winding side when the current of the neutral point CT on the control winding side of the valve control type reactor meets all the CT disconnection judging conditions; otherwise, preliminarily judging that the CT wire breakage does not occur on the control winding side;
the CT broken line judging conditions comprise that zero sequence current exists at the CT broken line side, differential current exists at the CT broken line phase, the reduction value of the voltage at the CT broken line side is less than 5V within 5ms, and no current exists at the CT broken line phase;
the method for determining whether CT disconnection occurs on the control winding side of the valve-controlled reactor comprises the following steps:
when the CT wire breakage on the control winding side is preliminarily judged and the CT current of the neutral point on the control winding side meets the condition of preventing the CT wire breakage misjudgment, judging that the grounding fault is in a control winding side generation area, locking the CT wire breakage judgment logic and preventing the CT wire breakage misjudgment; when the CT disconnection at the control winding side is preliminarily judged and the CT current at the neutral point at the control winding side does not meet the condition for preventing the CT disconnection from being judged by mistake, the CT disconnection at the control winding side is judged;
the condition for preventing CT disconnection misjudgment comprises that current flows through a neutral point CT on the winding side;
the method for judging the CT disconnection return on the control winding side based on the CT disconnection return judging logic comprises the following steps:
setting a plurality of CT broken line return judging conditions, controlling the CT broken line to return when the current on the control winding side of the valve control type reactor meets any one CT broken line return judging condition, and controlling the CT broken line not to return when the current on the control winding side does not meet all CT broken line return judging conditions;
the CT broken wire return judging conditions comprise no zero sequence current, three-phase current or three-phase no current.
2. The method for preventing the misjudgment of the CT fault line caused by the ground fault on the control winding side of the valve-controlled reactor according to claim 1, wherein the condition for judging that the current flows through the control winding side neutral point CT is that the current of the control winding side neutral point CT is greater than a threshold value.
3. The method for preventing the misjudgment of the CT fault line caused by the ground fault on the control winding side of the valve-controlled reactor according to claim 2, wherein the threshold value is 0.05 times of the CT secondary rated current value.
4. A device for preventing the misjudgment of CT broken lines caused by the ground fault of a control winding side of a valve-controlled reactor is characterized by comprising:
the voltage and current sensor is used for collecting voltage and current at the broken line side of the CT;
the CT disconnection judging module is used for preliminarily judging the CT disconnection at the control winding side of the valve control type reactor based on the CT disconnection judging logic according to the acquired voltage and current at the CT disconnection side;
the CT wire breakage misjudgment preventing module is used for further judging the preliminary judgment result of the CT wire breakage judging module according to the CT wire breakage misjudgment preventing logic and determining whether the CT wire breakage occurs on the control winding side of the valve control type reactor;
the CT broken wire return judging module is used for judging the CT broken wire return of the control winding side according to the CT broken wire return judging logic after the CT broken wire occurs on the control winding side and controlling the CT broken wire mark return according to the judging result;
the preliminary judgment method comprises the following steps:
setting a plurality of CT disconnection judging conditions, and preliminarily judging that CT disconnection occurs on the control winding side when the current of the neutral point CT on the control winding side of the valve control type reactor meets all the CT disconnection judging conditions; otherwise, preliminarily judging that the CT wire breakage does not occur on the control winding side;
the CT broken line judging conditions comprise that zero sequence current exists at the CT broken line side, differential current exists at the CT broken line phase, the reduction value of the voltage at the CT broken line side is less than 5V within 5ms, and no current exists at the CT broken line phase;
the method for determining whether the CT disconnection occurs on the control winding side of the valve-controlled reactor comprises the following steps:
when the CT disconnection at the control winding side is preliminarily judged and the CT current at the neutral point at the control winding side meets the condition of preventing the CT disconnection from being judged by mistake, the internal grounding fault of the control winding side generation area is judged, the CT disconnection judging logic is locked, and the CT disconnection from being judged by mistake is prevented; when the CT disconnection at the control winding side is preliminarily judged and the CT current at the neutral point at the control winding side does not meet the condition for preventing the CT disconnection from being judged by mistake, the CT disconnection at the control winding side is judged;
the condition for preventing CT disconnection misjudgment comprises that current flows through a neutral point CT on the winding side;
the method for judging the CT disconnection return on the control winding side based on the CT disconnection return judging logic comprises the following steps:
setting a plurality of CT broken line return judging conditions, controlling the CT broken line to return when the current on the control winding side of the valve control type reactor meets any one CT broken line return judging condition, and controlling the CT broken line not to return when the current on the control winding side does not meet all CT broken line return judging conditions;
the CT broken wire return judging conditions comprise no zero sequence current, three-phase current or three-phase no current.
5. A device for preventing the misjudgment of CT broken lines caused by the ground fault of a control winding side of a valve-controlled reactor is characterized by comprising a processor and a storage medium;
the storage medium is used for storing instructions;
the processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1 to 3.
6. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 3.
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| CN202010289459.3A CN111521951B (en) | 2020-04-14 | 2020-04-14 | Method and device for preventing misjudgment of CT (current transformer) broken line caused by grounding fault of control winding side of valve-controlled reactor and storage medium |
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| CN101630833A (en) * | 2009-08-21 | 2010-01-20 | 江西省电力公司超高压分公司 | Interturn protection method of high-voltage shunt reactor based on parameter unbalance detection |
| CN103117532B (en) * | 2013-02-28 | 2015-04-22 | 龙滩水电开发有限公司 | Zero-sequence voltage trip protection method for low-voltage side of transformers |
| CN103746350B (en) * | 2014-01-23 | 2016-11-16 | 国家电网公司 | high-sensitivity busbar differential protection method |
| CN105807174B (en) * | 2014-12-30 | 2019-02-15 | 施耐德电器工业公司 | Current transformer disconnection detection method in electrical power trans mission/distribution system protection |
| CN104882866B (en) * | 2015-05-27 | 2017-09-19 | 北京四方继保自动化股份有限公司 | A kind of method that protection device differentiates CT secondary sides broken string using pulsed quantity |
| CN105244859B (en) * | 2015-10-10 | 2017-12-19 | 江苏省电力公司苏州供电公司 | Prevent power network distance protection first start after decompression malfunction method |
| CN106291219B (en) * | 2016-10-10 | 2023-05-05 | 国网四川省电力公司技能培训中心 | Single-phase grounding/PT wire breakage fault automatic judging and alarming device and method |
| CN109119972B (en) * | 2018-09-19 | 2020-03-20 | 南京南瑞继保电气有限公司 | Locking method and device for preventing differential misoperation caused by CT (current transformer) disconnection of balance winding |
| CN110556783B (en) * | 2019-09-10 | 2021-10-22 | 许昌许继软件技术有限公司 | Zero sequence overcurrent protection method and device for transformer |
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2020
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