CN108736437A - A kind of adaptive fast-tripping zero-sequence current protections method - Google Patents

A kind of adaptive fast-tripping zero-sequence current protections method Download PDF

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Publication number
CN108736437A
CN108736437A CN201810520748.2A CN201810520748A CN108736437A CN 108736437 A CN108736437 A CN 108736437A CN 201810520748 A CN201810520748 A CN 201810520748A CN 108736437 A CN108736437 A CN 108736437A
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CN
China
Prior art keywords
sequence
zero
current
short circuit
reactance
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201810520748.2A
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Chinese (zh)
Inventor
宁景云
郭冰
陈钊
宁宁
宁
宁一
宁韦豪
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State Grid Corp of China SGCC
State Grid Tianjin Electric Power Co Ltd
Original Assignee
State Grid Corp of China SGCC
State Grid Tianjin Electric Power Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by State Grid Corp of China SGCC, State Grid Tianjin Electric Power Co Ltd filed Critical State Grid Corp of China SGCC
Priority to CN201810520748.2A priority Critical patent/CN108736437A/en
Publication of CN108736437A publication Critical patent/CN108736437A/en
Pending legal-status Critical Current

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Classifications

    • 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
    • H02H3/006—Calibration or setting of parameters
    • 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
    • H02H3/083—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 for three-phase systems

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  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a kind of adaptive fast-tripping zero-sequence current protections methods, include the following steps：1) Microcomputer Protection calculates the forward-sequence reactance X of circuit to be measured in real timeC1, negative sequence neactance XC2With zero-sequence reactance XC0；2) according to the forward-sequence reactance X calculated in step 1)C1, negative sequence neactance XC2, zero-sequence reactance XC0Calculate line end real-time earthing short circuit current I0And by short circuit current I0It is stored in memory RAM；3) judge the line fault electric current I that Microcomputer Protection measuresMWhether the line end real-time short circuit current I of in RAM real-time storage is more than0If judging result is "Yes", protective device action, otherwise, return to step 1)；The adaptive fast-tripping zero-sequence current protections method instantaneously can cut off failure when short circuit occurs in circuit by protective device, be effectively improved the sensitivity of protection.

Description

A kind of adaptive fast-tripping zero-sequence current protections method
Technical field
The present invention relates to power supply protection technical field, more particularly to a kind of adaptive fast-tripping zero-sequence current protections method.
Background technology
The setting valve of traditional fast-tripping zero-sequence current protections exports short circuit current in single phase grounding according to adjacent lines is avoided Setting valve calculates, and therefore, the short circuit current of calculating is multiplied by the setting valve obtained after tuning coefficient Krel in maximum operational mode Under can not achieve the 0s fast tripping protections of total track length 100% and I sections of protection domains will be made further to contract under minimum operational mode Short, in some cases it is also possible to making shielding failure, it is zero to make protection domain.
Fig. 1 is electric system simplified schematic diagram, it is assumed that the minimum forward-sequence reactance X in Fig. 1 under power system operation modeC1Most Small negative sequence neactance XC2It is 2 Ω, minimum zero-sequence reactance XC0For 5 Ω；Maximum positive sequence electricity in Fig. 1 under power system operation mode Anti- XC1With maximum negative sequence neactance XC2It is 4.5 Ω, minimum zero-sequence reactance XC0For 9 Ω；
Calculate the short circuit current in Fig. 1 when B busbar single-line to ground fault under maximum operational mode：
Single-phase short circuit current under maximum operational mode：
Three short circuit current under maximum operational mode：
I0max=3*Ik0max=3*2459=7377A
Single-phase short circuit current under minimum operational mode：
Three short circuit current under minimum operational mode：
I0min=3*2075=6225A
The setting valve of I sections of current quicks of zero sequence should export short circuit current in single phase grounding according to adjacent lines is avoided Setting valve calculates, and therefore, last short circuit current should also be multiplied by corresponding tuning coefficient Krel (taking 1.25 herein).Therefore, By taking maximum operational mode as an example, last three short circuit current should be：
I0p=Krel*Imax=1.25*7377=9221.25A
Short circuit current in single phase grounding, the short circuit current protection seting under maximum operational mode are exported in order to avoid adjacent lines Value has to be larger than 9221.25A.Following two conclusions are obtained by calculating analysis above：
(1) it conventionally calculates and adjusts definite value, since setting valve is bigger than normal, I sections of current quicks of zero sequence are in maximum It can not achieve the 0s fast tripping protections of total track length 100% under the method for operation；
(2) under minimum operational mode, since setting valve increase will be such that I sections of protection domains further shorten, in certain feelings There is a possibility that shielding failure, it is zero to make protection domain under condition；
Therefore, zero-sequence current protection does not react three-phase and line to line fault, does not also have when normal operation and system vibrate There is zero-sequence component generation, so it has preferable sensitivity.But zero-sequence current protection is influenced by power system operation mode transformation Larger, therefore sensitivity reduces, especially on short haul circuits and in complicated looped network, due to quick-action section protection domain too It is small, even without protection domain, causes the performance severe exacerbation of each section of zero-sequence current protection, keep operating time of protection very long, spirit Sensitivity is very low.
Invention content
The object of the present invention is to provide a kind of principles and implementation method of adaptive fast-tripping zero-sequence current protections.
For this purpose, technical solution of the present invention is as follows：
A kind of adaptive fast-tripping zero-sequence current protections method, including the following steps for carrying out in order：
1) the forward-sequence reactance X of Microcomputer Protection real time computation system power circuitC1, negative sequence neactance XC2With zero-sequence reactance XC0；
2) according to the forward-sequence reactance X calculated in step 1)C1, negative sequence neactance XC2, zero-sequence reactance XC0It is real-time to calculate line end Earth short circuit current I0, and by short circuit current I0It is stored in memory RAM, I0Change with the change of system operation mode, Therefore, the I being stored in RAM0Also it is updated at any time；
3) judge the fault current I that protective device measuresMMore than the fault current I of line end0When protection act, if sentencing Disconnected result is "Yes", protective device action；
4) continue to repeat step 1)~step 3).
Further, the step 2) short circuit currents I0Computational methods be：
Wherein XC1For forward-sequence reactance, XC2For negative sequence neactance, XC0For zero-sequence reactance, ESFor the voltage between phases of system operation.
Compared with prior art, which may be implemented to treat detecting system overall length reality Quickly protection is not influenced existing 100% 0s by system operation mode variation, when short circuit occurs in circuit, can instantaneously be passed through Protective device cuts off failure, is effectively improved the sensitivity of protection, greatly improves protective efficacy.
Description of the drawings
Fig. 1 is electric system simplified schematic diagram.
Fig. 2 is the flow chart of adaptive fast-tripping zero-sequence current protections method provided by the invention.
Specific implementation mode
Embodiment
Below in conjunction with the accompanying drawings and specific embodiment the present invention is described further, but following embodiments are absolutely not to this hair It is bright to have any restrictions.
A kind of adaptive fast-tripping zero-sequence current protections method, including the following steps for carrying out in order：
1) Microcomputer Protection calculates the forward-sequence reactance X of cable under test circuit in real timeC1, negative sequence neactance XC2With zero-sequence reactance XC0；
2) according to the forward-sequence reactance X calculated in step 1)C1, negative sequence neactance XC2, zero-sequence reactance XC0It is real-time to calculate line end Short circuit current I0And by short circuit current I0It is stored in memory RAM；
3) judgment step 1) the line fault electric current I that measures of Microcomputer ProtectionMMore than I0If judging result is "Yes", protection dress Set action；
4) continue to repeat step 1)~step 3).
Further, the step 2) short circuit currents I0Computational methods be：
Wherein XC1For forward-sequence reactance, XC2For negative sequence neactance, XC0For zero-sequence reactance, ESFor the voltage between phases of system operation.

Claims (2)

1. a kind of adaptive fast-tripping zero-sequence current protections method, which is characterized in that including the following steps carried out in order：
1) the forward-sequence reactance X of Microcomputer Protection real time computation systemC1, negative sequence neactance XC2With zero-sequence reactance XC0。
2) according to the forward-sequence reactance X calculated in step 1)C1, negative sequence neactance XC2, zero-sequence reactance XC0Calculate end busbar real-time earthing Short circuit current I0And it is stored in RAM memory, I0Change with changes of operating modes；
3)IMFault current when being any point failure of circuit that protective device measures, judges the fault current that protective device measures IMMore than the fault current I of line end0When protection act, 2) in calculate short circuit current I0If judging result is "Yes", protect Otherwise protection unit acts, into next step；
4) continue to repeat step 1)~step 3).
2. adaptive fast-tripping zero-sequence current protections method according to claim 1, which is characterized in that in the step 2) Short circuit current I0Computational methods be：
Wherein XC1For forward-sequence reactance, XC2For negative sequence neactance, XC0For zero-sequence reactance, ESFor the voltage between phases of system operation.
CN201810520748.2A 2018-05-28 2018-05-28 A kind of adaptive fast-tripping zero-sequence current protections method Pending CN108736437A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810520748.2A CN108736437A (en) 2018-05-28 2018-05-28 A kind of adaptive fast-tripping zero-sequence current protections method

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Application Number Priority Date Filing Date Title
CN201810520748.2A CN108736437A (en) 2018-05-28 2018-05-28 A kind of adaptive fast-tripping zero-sequence current protections method

Publications (1)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109298289A (en) * 2018-11-29 2019-02-01 广东电网有限责任公司 Localization method, system and the electronic equipment of distribution network failure point

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105186470A (en) * 2015-09-10 2015-12-23 国网江西省电力科学研究院 Single-phase ground fault processing method for 10kV ungrounded system
CN105552861A (en) * 2015-12-29 2016-05-04 河南省电力勘测设计院 Adaptive current protection algorithm
CN106340863A (en) * 2016-11-14 2017-01-18 国网天津市电力公司 Protection method for adaptive instantaneous current quick tripping

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105186470A (en) * 2015-09-10 2015-12-23 国网江西省电力科学研究院 Single-phase ground fault processing method for 10kV ungrounded system
CN105552861A (en) * 2015-12-29 2016-05-04 河南省电力勘测设计院 Adaptive current protection algorithm
CN106340863A (en) * 2016-11-14 2017-01-18 国网天津市电力公司 Protection method for adaptive instantaneous current quick tripping

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109298289A (en) * 2018-11-29 2019-02-01 广东电网有限责任公司 Localization method, system and the electronic equipment of distribution network failure point

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