CN111600277A - Delay calculation method applied to overcurrent protection - Google Patents

Delay calculation method applied to overcurrent protection Download PDF

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Publication number
CN111600277A
CN111600277A CN202010436036.XA CN202010436036A CN111600277A CN 111600277 A CN111600277 A CN 111600277A CN 202010436036 A CN202010436036 A CN 202010436036A CN 111600277 A CN111600277 A CN 111600277A
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Prior art keywords
current
sampling point
value
overcurrent protection
time counter
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CN111600277B (en
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丁晓兵
王风光
徐鹏
张弛
彭业
吕航
李力
杨贵
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China Southern Power Grid Co Ltd
NR Engineering Co Ltd
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China Southern Power Grid Co Ltd
NR Engineering Co Ltd
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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
    • H02H3/093—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 with timing means
    • H02H3/0935—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 with timing means the timing being determined by numerical means
    • 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
    • H02H3/02—Details
    • H02H3/05—Details with means for increasing reliability, e.g. redundancy arrangements
    • 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
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/20—Systems supporting electrical power generation, transmission or distribution using protection elements, arrangements or systems

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  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a time delay calculation method applied to overcurrent protection, which is used for acquiring digital current to obtain current amplitude
Figure DDA0002502287470000011
Sum current amplitude
Figure DDA0002502287470000012
Judging whether the two current amplitudes are equal, if not, resetting the time counter when the two current amplitudes are both smaller than the current fixed value threshold, if not, resetting the time counter when any one of the two current amplitudes is larger than the current fixed value threshold, or else, the two current amplitudes are equal but smaller than the current fixed value threshold
Figure DDA0002502287470000013
If the data quality is abnormal, the sampling point is considered as an abnormal sampling point, and the current time counter is calculated according to the previous sampling pointAnd the value t is used for performing overcurrent protection when the time counter t is greater than a preset time threshold value. The method solves the problem of slow movement or refusal movement of the overcurrent protection when the data quality is discontinuous and abnormal, and avoids the expansion of the accident range.

Description

Delay calculation method applied to overcurrent protection
Technical Field
The invention belongs to the field of relay protection of power systems.
Background
For the overcurrent protection, when the amplitude of the input current is greater than the current fixed value threshold and the time counter is greater than the time fixed value threshold, the overcurrent protection is performed. If the quality of the input current is abnormal, the current method is to lock the overcurrent protection function and clear the time counter.
When system faults occur and data quality is discontinuous and abnormal, the existing method can cause that overcurrent protection is refused to operate and the previous stage of protection action needing overcurrent protection trips, so that the accident range is expanded.
Disclosure of Invention
The purpose of the invention is as follows: in order to solve the problem that the prior art has the risk of refusing the action of overcurrent protection, the invention provides a delay calculation method applied to overcurrent protection.
The technical scheme is as follows: the invention provides a delay calculation method applied to overcurrent protection, which is applied to an overcurrent protection module of relay protection and specifically comprises the following steps:
step 1: when the current sampling point passes, the digital current in the overcurrent protection module is collected to obtain SV data, so that the current amplitude value is obtained
Figure BDA0002502287450000011
Sum current amplitude
Figure BDA0002502287450000012
Step 2: when in use
Figure BDA0002502287450000013
Less than a predetermined abnormal current threshold
Figure BDA0002502287450000014
Turning to step 3; otherwise, turning to the step 5;
and step 3: judging the current amplitude
Figure BDA0002502287450000015
Whether the current is greater than a preset current fixed value threshold value
Figure BDA0002502287450000016
If yes, turning to step 4; otherwise, resetting the time counter, and continuing to collect the next sampling point in the step 1;
and 4, step 4: judging the current amplitude
Figure BDA0002502287450000017
If not, the value t of the current time counter is t +1, and go to step 6; otherwise, the current sampling point is regarded as an abnormal sampling point, and the value t of the current time counter is calculated according to the last sampling point, and the step 6 is carried out;
and 5: judgment of
Figure BDA0002502287450000018
Or
Figure BDA0002502287450000019
Whether or not greater than
Figure BDA00025022874500000110
If yes, the current sampling point is also determined as an abnormal sampling point, and meanwhile, the sampling point is determined as the previous sampling pointCalculating the value t of the current time counter by the sampling point, and turning to step 6; otherwise, resetting the time counter, and continuing to collect the next sampling point in the step 1;
step 6: judging whether the value t of the current time counter is greater than a preset time threshold value, if so, starting overcurrent protection; otherwise, turning to the step 1, and continuing to collect the next sampling point.
Further, the specific method for calculating the value of the current time counter according to the previous sampling point in the steps 4 and 5 is as follows: judging whether the last sampling point is an abnormal sampling point, if so, judging that the current sampling point is the nth abnormal sampling point in the continuous abnormal sampling points, and when t is-1-nk<When t is 0, t is 0-1When-nk is more than or equal to 0, t is t-1-nk, where k is a coefficient and k > 1, t-1The value of the time counter corresponding to the last sampling point; otherwise, when t-1-k<When t is 0, t is 0-1When-k is greater than or equal to 0, t is t-1-k。
Further, when the current value IN of the current transformer is 1A,
Figure BDA0002502287450000021
the value range of (A) is 0.04-0.06A; when the current rating value IN of the current transformer is 5A,
Figure BDA0002502287450000022
the value range of (A) is 0.2-0.3A.
Further, when the overcurrent protection of the relay protection is phase overcurrent protection, the time counter adopts a split-phase counter, and each phase counter is independent.
Has the advantages that: compared with the prior art, the method can reduce the risk of slow movement or refusal movement of overcurrent protection when system failure occurs and data quality is in discontinuous abnormity, thereby keeping the protection function as much as possible and preventing the accident scope from being expanded.
Drawings
FIG. 1 is a flow chart of the present invention.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention.
As shown in fig. 1, the present embodiment provides a delay calculation method applied to overcurrent protection, which specifically includes the following steps:
step 1: when the current sampling point passes, the first and second acquisition modules simultaneously acquire the digital current in the overcurrent protection module to obtain SV data (sampling data), and the current amplitude value is calculated according to the digital current acquired by the first acquisition module in the SV data
Figure BDA0002502287450000023
Calculating to obtain a current amplitude value according to the digital current acquired by the second acquisition module in the SV data
Figure BDA0002502287450000024
In this embodiment, a Link sampling Valid bit (Valid), a Link communication normal bit (Link), and a Link communication Enable bit (Enable) in SV data quality are processed respectively.
Step 2: when in use
Figure BDA0002502287450000025
Less than a predetermined abnormal current threshold
Figure BDA0002502287450000026
Turning to step 4; otherwise, turning to the step 3.
And step 3: judgment of
Figure BDA0002502287450000027
Or
Figure BDA0002502287450000028
Whether the current is greater than a preset current fixed value threshold value
Figure BDA0002502287450000029
If yes, the current sampling point is determined as an abnormal sampling point,and 6, calculating the value t of the current time counter according to the last sampling point, and turning to the step 6. If it is
Figure BDA00025022874500000210
And
Figure BDA0002502287450000031
are all less than the preset current constant value threshold
Figure BDA0002502287450000032
And if the time counter t is equal to 0, continuing to acquire the digital current of the next sampling point, and turning to the step 1.
And 4, step 4: judging the current amplitude
Figure BDA0002502287450000033
Whether or not greater than
Figure BDA0002502287450000034
And (5) if so, continuing to collect the digital current of the next sampling point, and turning to the step 1, otherwise, keeping the time counter t equal to 0.
And 5: judgment of
Figure BDA0002502287450000035
If the data quality is normal, the value t of the current time counter is t +1, and go to step 6; otherwise, the current sampling point is determined as an abnormal sampling point, and the value t of the current time counter is calculated according to the last sampling point.
Step 6: judging whether t is greater than a preset time threshold value, if yes, performing overcurrent protection action; and otherwise, continuously acquiring the digital current of the next sampling point, and turning to the step 1.
In this embodiment, when the Enable bit in the SV data quality is 1, if the Valid bit is 0 or the Link bit is 0, the data quality is considered to be abnormal; when the Enable bit in the SV data quality is 1, if the Valid bit is 1 and the Link bit is 1, the data quality is considered to be normal; when the Enable bit in the SV data quality is 0, the overcurrent protection function is exited.
Preferably, when currently minedWhen the sampling point is an abnormal sampling point, the specific method for calculating the value t of the current time counter is as follows: judging whether the last sampling point is an abnormal sampling point, if so, judging that the current sampling point is the nth abnormal sampling point in the continuous abnormal sampling points, and when t is-1-nk<When t is 0, t is 0-1When-nk is more than or equal to 0, t is t-1-nk, where k is a coefficient and k > 1, t-1The value of the time counter corresponding to the last sampling point; otherwise, when t-1-k<When t is 0, t is 0-1When-k is greater than or equal to 0, t is t-1-k。
Preferably, when the current rating value IN of the current transformer is 1A,
Figure BDA0002502287450000036
the value range of (A) is 0.04-0.06A; when the current rating value IN of the current transformer is 5A,
Figure BDA0002502287450000037
the value range of (A) is 0.2-0.3A.
Preferably, in this embodiment, when the overcurrent protection is phase overcurrent protection, the time counter is a split-phase counter, and when the data quality of a certain phase current SV is abnormal, only the time counter corresponding to the phase current protection is affected, and the other two phase time counters are not affected.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.

Claims (4)

1. A delay calculation method applied to overcurrent protection is applied to an overcurrent protection module of relay protection, and is characterized by comprising the following steps:
step 1: when the current sampling point passes, the digital current in the overcurrent protection module is collected to obtain SV data, so that the current amplitude value is obtained
Figure FDA0002502287440000011
Sum current amplitude
Figure FDA0002502287440000012
Step 2: when in use
Figure FDA0002502287440000013
Less than a predetermined abnormal current threshold
Figure FDA0002502287440000014
Turning to step 3; otherwise, turning to the step 5;
and step 3: judging the current amplitude
Figure FDA0002502287440000015
Whether the current is greater than a preset current fixed value threshold value
Figure FDA0002502287440000016
If yes, turning to step 4; otherwise, resetting the time counter, and continuing to collect the next sampling point in the step 1;
and 4, step 4: judging the current amplitude
Figure FDA0002502287440000017
If not, the value of the time counter is t ═ t +1, and go to step 6; otherwise, the current sampling point is regarded as an abnormal sampling point, and the value t of the current time counter is calculated according to the last sampling point, and the step 6 is carried out;
and 5: judgment of
Figure FDA0002502287440000018
Or
Figure FDA0002502287440000019
Whether or not greater than
Figure FDA00025022874400000110
If so, identifying the current sampling point as an abnormal sampling point, simultaneously calculating the value t of the current time counter according to the last sampling point, and turning to the step 6; otherwise, resetting the time counter, and continuing to collect the next sampling point in the step 1;
step 6: judging whether the value t of the current time counter is greater than a preset time threshold value, if so, starting overcurrent protection; otherwise, turning to the step 1, and continuing to collect the next sampling point.
2. The delay calculation method applied to overcurrent protection according to claim 1, wherein in steps 4 and 5: the specific method for calculating the value t of the current time counter according to the last sampling point comprises the following steps: judging whether the last sampling point is an abnormal sampling point, if so, judging that the current sampling point is the nth abnormal sampling point in the continuous abnormal sampling points, and when t is-1When-nk < 0, t is 0, when t is-1When-nk is more than or equal to 0, t is t-1-nk, where k is a coefficient and k > 1, t-1The value of the time counter corresponding to the last sampling point; otherwise, when t-1When k < 0, t is 0, when t is-1When-k is greater than or equal to 0, t is t-1-k。
3. The delay calculation method applied to overcurrent protection according to claim 1, wherein when the current rating IN of the current transformer is 1A,
Figure FDA00025022874400000111
the value range of (A) is 0.04-0.06A; when the current rating value IN of the current transformer is 5A,
Figure FDA00025022874400000112
the value range of (A) is 0.2-0.3A.
4. The delay calculating method applied to overcurrent protection according to claim 1, wherein when the overcurrent protection of the relay protection is phase overcurrent protection, the time counter is a split-phase counter, and each phase counter is independent of each other.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1124418A (en) * 1994-03-25 1996-06-12 尹顿公司 Overcurrent trip unit with separately adjustable neutral protection
CN102761106A (en) * 2012-07-10 2012-10-31 清华大学 Quick starting and vector calculation method for intelligent substation integrated protection
CN102901943A (en) * 2011-12-24 2013-01-30 许继集团有限公司 Regional power grid-based sample data exception detection and over-current protection method
CN106998054A (en) * 2017-05-24 2017-08-01 南京国电南自电网自动化有限公司 A kind of intelligent substation data reliability recognition methods based on information fusion
CN107069664A (en) * 2017-06-19 2017-08-18 南京国电南自电网自动化有限公司 A kind of method for preventing current sample abnormal data from being influenceed on current protection
CN107658852A (en) * 2017-11-15 2018-02-02 南京南瑞继保电气有限公司 A kind of guard method of AC excitation synchronous machinery excitation winding phase fault and system
CN109245049A (en) * 2018-11-13 2019-01-18 南京南瑞继保电气有限公司 A kind of AC excitation synchronous electric motor rotor winding overcurrent protection method and device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1124418A (en) * 1994-03-25 1996-06-12 尹顿公司 Overcurrent trip unit with separately adjustable neutral protection
CN102901943A (en) * 2011-12-24 2013-01-30 许继集团有限公司 Regional power grid-based sample data exception detection and over-current protection method
CN102761106A (en) * 2012-07-10 2012-10-31 清华大学 Quick starting and vector calculation method for intelligent substation integrated protection
CN106998054A (en) * 2017-05-24 2017-08-01 南京国电南自电网自动化有限公司 A kind of intelligent substation data reliability recognition methods based on information fusion
CN107069664A (en) * 2017-06-19 2017-08-18 南京国电南自电网自动化有限公司 A kind of method for preventing current sample abnormal data from being influenceed on current protection
CN107658852A (en) * 2017-11-15 2018-02-02 南京南瑞继保电气有限公司 A kind of guard method of AC excitation synchronous machinery excitation winding phase fault and system
CN109245049A (en) * 2018-11-13 2019-01-18 南京南瑞继保电气有限公司 A kind of AC excitation synchronous electric motor rotor winding overcurrent protection method and device

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Title
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