CN102005738A - Method for identifying healthy phase saturation based on current amplitude ratio and differential current harmonic wave - Google Patents

Method for identifying healthy phase saturation based on current amplitude ratio and differential current harmonic wave Download PDF

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CN102005738A
CN102005738A CN2010105887460A CN201010588746A CN102005738A CN 102005738 A CN102005738 A CN 102005738A CN 2010105887460 A CN2010105887460 A CN 2010105887460A CN 201010588746 A CN201010588746 A CN 201010588746A CN 102005738 A CN102005738 A CN 102005738A
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fault
current
difference stream
phase
differential
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郑玉平
戴魏
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占捷文
姚刚
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State Grid Electric Power Research Institute
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Abstract

The invention provides a method for identifying healthy phase saturation based on current amplitude ratio and differential current harmonic wave. A healthy phase is braked by utilizing fault phase brake current, healthy phase differential protection is locked in healthy phase saturation, and the differential protection is opened when the differential current harmonic wave is smaller according to the characteristics of the differential current harmonic wave so as to ensure that the differential protection can release the outlet in double-phase earthfault and regional high-resistance fault. By using the method, differential misoperation in healthy phase saturation can be well prevented, and error-lock can not occur in transformational fault, developmental fault and other situations.

Description

Discern the mutually saturated method of non-fault based on the current amplitude ratio with difference stream harmonic wave
Technical field
The present invention relates to the mutually saturated method of discrimination of the non-fault of a kind of electric power system.
Background technology
In some regional on-the-spot actual moving process, after outside the system busbar district single-phase fault taking place, the mutation current of passing through property appears in non-fault phase secondary circuit in the recent period, and misoperation has appearred in non-fault phase current differential protection.Its principal character is: distinguish outer single-phase fault, the peaked wave electric current of several cycles appears in non-fault mutually.The saturated criterion of the anti-CT of domestic protection equipment for busbar mainly is to utilize secondary current correctly on the progress of disease basis; be that CT can not enter saturated at once after the fault; one section linear work district is arranged; referring to Cheng Lijun etc. " based on the research of the CT saturation detection scheme of sampled value ". relay, 2000.28 (8): 19-21.Because non-fault phase fault starting and current differential protection move simultaneously, asynchronous method (time difference method) is judged to troubles inside the sample space, does not have Blocking Differential Protection, and non-fault is sent out trip signal mutually, has enlarged the accident scope.
These two kinds of phenomenons all are the behaviors of non-fault phase differential protection generation malfunction in the differential current protection.Get rid of line mutual-inductance in the testing crew investigation process at the scene item by item; increasing-aid current; the influence of factors such as protective device and secondary circuit defective; analyze the wiring of protection and secondary circuit; check the action behavior of protective device; set about from resolving the on-the-spot failure wave-recording information of extracting; according to on-the-spot operating current and voltage waveform; when bus or circuit generation single-phase fault; fault phase short circuit current is not very big; about the 5-6 during for rated current times; but DC component aperiodic with very big decay; the Current Transformer Secondary side of fault phase does not take place saturated; but be the meet burr mutation current of peaked wave that 2-3 cycle occur of non-fault, the direction of mutation current and the fault direction of short circuit current mutually are anti-phase substantially, and non-fault phase current produces distortion; non-fault phase differential current satisfies the ratio brake criterion; referring to Yuan Yubo, 5 snowy peaks, Deng Jieqing etc. " the current transformer three-phase current is gone here and there mutually to the influence of differential protection ". Automation of Electric Systems; 2010,34 (21): 65-68.The visible processing scheme to the problems referred to above of document is generally the saturation characteristic of current transformer is carried out verification at present; Whether the wiring of paying close attention to the secondary circuit neutral point has the phenomenon of loose contact or insulation damages; Carry out type selecting in strict accordance with the protective current transformer, technical conditions; processing method at secondary circuit such as to change to ineligible current transformer; referring to Yuan Yubo; 5 snowy peaks; Deng Jie is clear etc. and " the current transformer three-phase current is gone here and there mutually to the influence of differential protection ". Automation of Electric Systems; 2010,34 (21): 65-68.
Summary of the invention
Goal of the invention
The objective of the invention is: the fault phase current flows through the CT secondary side neutral line and is coupled with non-fault and causes non-fault mutually saturated during the resolution system fault, and time difference method is judged non-fault by accident the problem that causes non-fault phase differential protection action for troubles inside the sample space mutually.
Technical scheme
In order to solve above technical problem; the present invention proposes based on three-phase current amplitude proportion and difference stream harmonic wave; discern the saturated method of non-fault phase CT; it is characterized in that: utilize fault phase stalling current to brake non-fault phase; the non-fault phase of locking differential protection when non-fault is mutually saturated; simultaneously according to difference stream harmonic characteristic at a difference stream harmonic wave hour open differential protection, differential protection can be opened outlet when guaranteeing in double earthfault, the district high resistive fault.
The operating characteristics of the sudden change amount ratio-differential relay of general current differential protection is:
Figure 56563DEST_PATH_IMAGE001
（1）
Figure 335098DEST_PATH_IMAGE002
（2）
Wherein
Figure 217603DEST_PATH_IMAGE003
Be sudden change amount difference stream amplitude,
Figure 163562DEST_PATH_IMAGE004
Be prominent residual quantity stalling current amplitude,
Figure 840531DEST_PATH_IMAGE005
Be differential startup threshold, k is the ratio restraint coefficient.
From the above mentioned, when non-fault occurs when saturated mutually, general non-fault sudden change amount mutually difference stream is bigger, and with non-fault sudden change amount mutually stalling current sizableness, so formula (1) and formula (2) are not enough to brake.But fault this moment sudden change amount mutually stalling current is generally bigger; based on these characteristics; the present invention adopts fault sudden change amount mutually stalling current to brake non-fault phase; when sudden change amount difference stream during greater than a certain proportion of maximal phase sudden change amount stalling current; open differential protection; otherwise Blocking Differential Protection, as the formula (3):
Figure 747308DEST_PATH_IMAGE006
? （3）
Wherein
Figure 433504DEST_PATH_IMAGE007
Be maximal phase sudden change amount stalling current amplitude,
Figure 233970DEST_PATH_IMAGE008
Be non-fault phase saturation mutation amount restraint coefficient.
It is different to consider that fault phase current when non-fault is mutually saturated flows through the pro rate relation of non-fault phase CT secondary circuit; and fault sudden change amount mutually stalling current can be decayed in time; the reliably locking in some cases of sudden change amount braking criterion; therefore the present invention adopts fault phase stable state stalling current to brake non-fault phase; when stable state difference stream during greater than a certain proportion of maximal phase stalling current; open differential protection, otherwise Blocking Differential Protection
Figure 347419DEST_PATH_IMAGE009
（4）
Wherein Be maximal phase stalling current amplitude,
Figure 965799DEST_PATH_IMAGE011
For non-fault differs the stream amplitude,
Figure 886351DEST_PATH_IMAGE012
Be the mutually saturated steady-state quantity restraint coefficient of non-fault.
In the taking into account system generating region during double earthfault; fault phase current difference is bigger; said method may cause the mistake locking; in order to reduce this risk; increase the open differentiation of difference stream harmonic wave; main is just in time opposite according to the time dependent trend of difference stream harmonic content that is troubles inside the sample space and the mutually saturated formation of non-fault; troubles inside the sample space difference stream harmonic content can change gradually in time and diminish; but not the harmonic content of the difference stream of the mutually saturated formation of fault can increase with changing gradually fault time; therefore the present invention adopts and judges that the method that harmonic component in the difference stream accounts for difference stream fundametal compoment ratio addresses the above problem; the harmonic component of being on duty in the stream hour; open differential protection, as the formula (5)
Figure 170702DEST_PATH_IMAGE013
（5）
Wherein
Figure 786491DEST_PATH_IMAGE014
Be the humorous wave amplitude of difference stream,
Figure 814490DEST_PATH_IMAGE015
Be difference stream fundamental voltage amplitude.
The logic diagram of above method as shown in drawings.
Beneficial effect
1) brake non-fault phase mutually with fault, made full use of the mutually saturated substantive characteristics of non-fault, principle is simple and reliable, can reliable locking when the mutually saturated time difference method of non-fault is judged by accident.
2) this method does not only influence the responsiveness and the operating characteristics of the prominent difference of normal fault relay, can also well prevent misoperation differential when non-fault is mutually saturated, can not miss locking in situations such as evolved fault, developing faults.
3) utilize difference stream harmonic wave open, differential protection operating characteristics when not influencing evolved fault, when outside the bus district takes place, changeing in troubles inside the sample space, the district high resistive fault, can Blocking Differential Protection.
Description of drawings
Accompanying drawing is the logic diagram of the saturated differentiation of the present invention non-fault phase CT.
Embodiment
Embodiment below in conjunction with a half breaker bus mode of connection describes in further detail the present invention.But the invention is not restricted to given example.
1) AC sampling: the current sampling data that obtains each branch road of bus.
2) calculate each branch current sudden change amount ,
Figure 44800DEST_PATH_IMAGE017
Sign branch road number.
3) calculate each branch current fundametal compoment
Figure 413464DEST_PATH_IMAGE018
,
Figure 979575DEST_PATH_IMAGE019
Sign branch road number.
4) calculate bus three-phase sudden change amount difference stream
Figure 609139DEST_PATH_IMAGE020
, sudden change amount stalling current
Figure 235293DEST_PATH_IMAGE021
, stable state difference stream
Figure 825674DEST_PATH_IMAGE022
, the stable state stalling current
5) calculate difference stream total harmonic distortion, computing formula is:
Figure 945126DEST_PATH_IMAGE024
,
Figure 742180DEST_PATH_IMAGE025
Be the root mean square value of difference stream,
Figure 819858DEST_PATH_IMAGE026
DC component for difference stream.
6) when system's generation disturbance, as the non-latching differential protection of time difference method, sudden change amount ratio differential condition satisfy (
Figure 727771DEST_PATH_IMAGE001
, ),
Figure 299883DEST_PATH_IMAGE028
Condition satisfies, and satisfies simultaneously
Figure 864857DEST_PATH_IMAGE029
Or
Figure 576461DEST_PATH_IMAGE013
, then open differential relay, otherwise locking differential relay.

Claims (1)

1. discern the mutually saturated method of non-fault based on the current amplitude ratio with difference stream harmonic wave, it is characterized in that, may further comprise the steps:
1) AC sampling: the current sampling data that obtains each branch road of bus;
2) calculate each branch current sudden change amount
Figure 412764DEST_PATH_IMAGE001
,
Figure 935013DEST_PATH_IMAGE002
Sign branch road number;
3) calculate each branch current fundametal compoment
Figure 368268DEST_PATH_IMAGE003
,
Figure 848928DEST_PATH_IMAGE002
Sign branch road number;
4) calculate bus three-phase sudden change amount difference stream
Figure 610210DEST_PATH_IMAGE004
, sudden change amount stalling current
Figure 60783DEST_PATH_IMAGE005
, stable state difference stream
Figure 223911DEST_PATH_IMAGE006
, the stable state stalling current
Figure 875473DEST_PATH_IMAGE007
, wherein,
Figure 514264DEST_PATH_IMAGE008
5) calculate difference stream total harmonic distortion, computing formula is:
Figure 909474DEST_PATH_IMAGE009
,
Figure 927108DEST_PATH_IMAGE010
Be the root mean square value of difference stream,
Figure 15150DEST_PATH_IMAGE011
DC component for difference stream;
6) when system's generation disturbance,, satisfy simultaneously as the non-latching differential protection of time difference method
Figure 875659DEST_PATH_IMAGE012
,
Figure 808980DEST_PATH_IMAGE013
,
Figure 946700DEST_PATH_IMAGE014
, and satisfy
Figure 205643DEST_PATH_IMAGE015
With
Figure 694393DEST_PATH_IMAGE016
One of the time, then open differential relay, otherwise locking differential relay, wherein, Be sudden change amount difference stream amplitude,
Figure 813845DEST_PATH_IMAGE018
Be prominent residual quantity stalling current amplitude,
Figure 446951DEST_PATH_IMAGE019
Be differential startup threshold, k is the ratio restraint coefficient;
Figure 688577DEST_PATH_IMAGE020
Be maximal phase sudden change amount stalling current amplitude,
Figure 822755DEST_PATH_IMAGE021
Be non-fault phase saturation mutation amount restraint coefficient;
Figure 200647DEST_PATH_IMAGE022
Be maximal phase stalling current amplitude,
Figure 270234DEST_PATH_IMAGE023
For non-fault differs the stream amplitude,
Figure 733576DEST_PATH_IMAGE024
Be the mutually saturated steady-state quantity restraint coefficient of non-fault; Be the humorous wave amplitude of difference stream,
Figure 169423DEST_PATH_IMAGE026
Be difference stream fundamental voltage amplitude.
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Cited By (9)

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CN102279338A (en) * 2011-04-29 2011-12-14 上海磁浮交通发展有限公司 Method for monitoring two-phase grounding fault of magnetic levitation stator coil
CN103529321A (en) * 2013-10-10 2014-01-22 长园深瑞继保自动化有限公司 Current transformer saturation detecting method
WO2015000227A1 (en) * 2013-07-04 2015-01-08 Wen Jie Bus protection method for quick locking in ct asymmetrical wire breakage
CN105024356A (en) * 2014-06-19 2015-11-04 许继电气股份有限公司 Ratio braking type protection method for bus with voltage class of 35 kV or below
CN109375131A (en) * 2018-07-31 2019-02-22 中国电力科学研究院有限公司 A kind of saturated velocity of current transformer and saturation depth recognition methods and system
CN109768526A (en) * 2019-03-13 2019-05-17 南京南瑞继保电气有限公司 A kind of method and apparatus being mutually saturated based on current distribution factor identification non-faulting
CN110927523A (en) * 2019-11-29 2020-03-27 国电南瑞科技股份有限公司 Fault positioning method for flexible direct-current power distribution network
CN112782494A (en) * 2019-11-05 2021-05-11 南京南瑞继保电气有限公司 Saturation identification method and device for shunt reactor
WO2021174631A1 (en) * 2020-03-02 2021-09-10 国电南瑞科技股份有限公司 Power transmission line distance protection current transformer saturation identification method and system

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102279338B (en) * 2011-04-29 2013-09-25 上海磁浮交通发展有限公司 Method for monitoring two-phase grounding fault of magnetic levitation stator coil
CN102279338A (en) * 2011-04-29 2011-12-14 上海磁浮交通发展有限公司 Method for monitoring two-phase grounding fault of magnetic levitation stator coil
WO2015000227A1 (en) * 2013-07-04 2015-01-08 Wen Jie Bus protection method for quick locking in ct asymmetrical wire breakage
CN103529321B (en) * 2013-10-10 2016-01-20 长园深瑞继保自动化有限公司 CT saturation detection method
CN103529321A (en) * 2013-10-10 2014-01-22 长园深瑞继保自动化有限公司 Current transformer saturation detecting method
CN105024356B (en) * 2014-06-19 2018-05-29 许继电气股份有限公司 A kind of 35kV and following voltage class ratiometric dynamic formula bus bar protecting method
CN105024356A (en) * 2014-06-19 2015-11-04 许继电气股份有限公司 Ratio braking type protection method for bus with voltage class of 35 kV or below
CN109375131A (en) * 2018-07-31 2019-02-22 中国电力科学研究院有限公司 A kind of saturated velocity of current transformer and saturation depth recognition methods and system
CN109375131B (en) * 2018-07-31 2022-03-04 中国电力科学研究院有限公司 Method and system for identifying saturation speed and saturation depth of current transformer
CN109768526A (en) * 2019-03-13 2019-05-17 南京南瑞继保电气有限公司 A kind of method and apparatus being mutually saturated based on current distribution factor identification non-faulting
CN109768526B (en) * 2019-03-13 2020-09-04 南京南瑞继保电气有限公司 Method and device for identifying non-fault phase saturation based on current distribution coefficient
CN112782494A (en) * 2019-11-05 2021-05-11 南京南瑞继保电气有限公司 Saturation identification method and device for shunt reactor
CN112782494B (en) * 2019-11-05 2023-10-17 南京南瑞继保电气有限公司 Saturation identification method and device for shunt reactor
CN110927523A (en) * 2019-11-29 2020-03-27 国电南瑞科技股份有限公司 Fault positioning method for flexible direct-current power distribution network
WO2021174631A1 (en) * 2020-03-02 2021-09-10 国电南瑞科技股份有限公司 Power transmission line distance protection current transformer saturation identification method and system

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