CN113991597A - Intelligent reclosing method for overhead line-cable hybrid line - Google Patents

Intelligent reclosing method for overhead line-cable hybrid line Download PDF

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CN113991597A
CN113991597A CN202111035903.XA CN202111035903A CN113991597A CN 113991597 A CN113991597 A CN 113991597A CN 202111035903 A CN202111035903 A CN 202111035903A CN 113991597 A CN113991597 A CN 113991597A
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reclosing
sides
section
judging
current
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Inventor
刘安文
章立宗
沈祥
许海峰
王军慧
王松
金乃正
秦建松
戚宣威
汪磊
李勇
闫志坤
刘学
陈明
董钦
贺明
曹文斌
金钢
陆金凤
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Shaoxing Daming Electric Power Construction Co ltd
Shaoxing Jianyuan Electric Power Group Co ltd
NR Engineering Co Ltd
Electric Power Research Institute of State Grid Zhejiang Electric Power Co Ltd
Shaoxing Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
Original Assignee
Shaoxing Daming Electric Power Construction Co ltd
Shaoxing Jianyuan Electric Power Group Co ltd
NR Engineering Co Ltd
Electric Power Research Institute of State Grid Zhejiang Electric Power Co Ltd
Shaoxing Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
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Priority to CN202111035903.XA priority Critical patent/CN113991597A/en
Publication of CN113991597A publication Critical patent/CN113991597A/en
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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
    • H02H3/02—Details
    • H02H3/06—Details with automatic reconnection
    • H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured

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Abstract

The invention discloses an intelligent reclosing method for an overhead line-cable hybrid line, which comprises the following steps: dividing the hybrid line into N consecutive sections; respectively installing an acquisition unit between every two adjacent sections, and acquiring the three-phase current of each installation point in real time; station end reclosing judging devices are respectively installed on two sides of the circuit, and three-phase currents on the respective sides are collected in real time; each acquisition unit sends the three-phase current to the station end reclosing judgment devices on the two sides, and the station end reclosing judgment devices on the two sides send the three-phase current to the opposite side; the reclosing judging devices at the station ends at the two sides judge section faults according to current data at the respective sides and the received current data, and output corresponding reclosing signals according to section fault judging results; has the advantages that: and fault section positioning is carried out on the hybrid line according to the differential criterion and the overcurrent criterion, so that whether the hybrid line needs to be reclosed or not is guided, and the safe and stable operation of the power grid is improved.

Description

Intelligent reclosing method for overhead line-cable hybrid line
Technical Field
The invention relates to the field of relay protection of power transmission lines, in particular to an intelligent reclosing method for an overhead line-cable hybrid line.
Background
Currently, there are a large number of hybrid overhead line-cable lines in the power grid. Overhead lines run in mountains and fields, cables are buried in the ground or the sea floor, and when the overhead lines or the cables have faults, the accurate positions of the faults are difficult to determine. Overhead line faults are mostly transient faults, while cable faults are mostly permanent faults due to manufacturing flaws or insulation degradation over time. In order to improve the reliability of power supply, automatic reclosing is generally adopted for line protection. However, for a permanent fault, reclosing will cause another impact on the system, which affects the stable operation of the system. This requires fault location of the overhead line-cable hybrid line, which should be implemented when a fault occurs in the overhead line section and locked when a fault occurs in the cable section.
Patent CN201910565929.1 "a rapid positioning device and positioning method for faults of an overhead-cable hybrid line", can monitor faults of the overhead-cable hybrid line in real time. However, the hyperbolic voltage equation needs to be solved in the process, and the method is not suitable for practical engineering application.
The fault location can also be carried out on the hybrid line through fault location, and the fault location algorithm of the hybrid line can be mainly divided into a traveling wave method and a fault analysis method according to different location principles. The travelling wave method has the advantages of high ranging speed, no influence of transition resistance and the like, but is easily influenced by repeated folding and reflection of travelling waves at joints of overhead lines and cable lines, has the problem of wave head identification, needs to invest special equipment and has relatively complex technology. The fault analysis method has low requirement on equipment, small investment and strong engineering practicability, but has the problems of large calculation amount and false root identification when the line distribution parameters are used for searching and calculating, and the distance measurement precision of the algorithm for fault positioning by adopting the searching and calculating is also influenced by the threshold value.
Disclosure of Invention
In order to solve the above problems, an object of the present invention is to provide an intelligent reclosing method for an overhead line-cable hybrid line, which performs fault location on the hybrid line and accordingly determines whether to perform reclosing on the hybrid line.
An intelligent reclosing method for an overhead line-cable hybrid line comprises the following steps:
dividing a mixed line into N continuous sections according to an overhead line section and a cable section;
secondly, mounting an acquisition unit between every two adjacent sections, and acquiring the three-phase current of each mounting point in real time by each acquisition unit;
respectively installing station end reclosing judgment devices on two sides of the mixed line, and respectively collecting three-phase currents on the respective sides of the mixed line in real time by the station end reclosing judgment devices on the two sides;
step four, each acquisition unit respectively sends the three-phase current of each installation point to station end reclosing judging devices on two sides, and the station end reclosing judging devices on two sides send the three-phase current of each side to the station end reclosing judging device on the opposite side;
fifthly, judging section faults by reclosing judging devices at the station ends at two sides according to current data at the respective sides and the received current data, and outputting corresponding reclosing signals according to a section fault judging result, wherein the section fault judging comprises the following criteria:
judging that the section K has a fault when the differential current of the currents on the two sides of the section K is larger than a differential current fixed value;
judging that the region K has a fault when the current on one side is greater than an overcurrent fixed value and the current on the other side is less than the overcurrent fixed value in the currents on the two sides of the region K;
the first criterion and the second criterion are in an OR relationship, and if any one of the first criterion and the second criterion is satisfied, the region K is judged to have a fault, wherein K is more than or equal to 1 and less than or equal to N.
Further, the specific method for the reclosing judging device of the two side station ends to output the corresponding reclosing signal according to the section fault judging result is as follows:
when any cable section has a fault, the station end reclosing judging device outputs a reclosing signal;
when all cable sections have no faults, the station end reclosing criterion device does not output a reclosing signal.
Further, the specific formula of the differential criterion is as follows:
Figure RE-GDA0003305685760000031
phi is three phases of A, B and C;
wherein: i isKdΦIn order to obtain a differential current in the section K,
Figure RE-GDA0003305685760000032
the amplitude of the vector sum of the currents on the two sides of the section K is obtained;
IKrΦbraking current for section K;
Figure RE-GDA0003305685760000033
the amplitude of the current vector difference on the two sides of the section K is obtained;
Idsetsetting the differential current;
IK1Φ、IK2Φrespectively, the current on both sides of the section K.
Further, the specific formula of the overcurrent criterion is as follows:
Figure RE-GDA0003305685760000034
or
Figure RE-GDA0003305685760000035
Phi is three-phase of A, B and C
Wherein: i isK1Φ、IK2ΦRespectively are currents on two sides of the section K; i islsetThe value is determined for overcurrent.
The invention has the advantages that: all criteria are completed through station end reclosing judging devices on two sides of the hybrid line, and fault section positioning is carried out on the hybrid line according to differential criteria and overcurrent criteria, so that whether the hybrid line needs reclosing or not is guided, safe and stable operation of a power grid is guaranteed, and engineering practicability is achieved.
Drawings
Fig. 1 is a flowchart of an intelligent reclosing method for an overhead line-cable hybrid line in an embodiment;
fig. 2 is a schematic diagram of installation and three-phase current trend of a collecting unit and a station-side reclosing judging device in an overhead line-cable hybrid line in the embodiment.
Detailed Description
The present invention will be described in further detail with reference to examples.
The embodiment provides an intelligent reclosing method for an overhead line-cable hybrid line, as shown in fig. 1 and 2, comprising the following steps:
firstly, dividing a hybrid line into a section 1, a section 2, … … and a section N according to an overhead line section and a cable line section, for example, the section 1 in fig. 2 represents an overhead line section, and the section 2 represents a cable section;
secondly, respectively installing acquisition units between sections 2 in section 1, between sections 3 in section 2, between … … and between sections N-1, and respectively acquiring the three-phase current of respective installation points in real time by each acquisition unit;
respectively installing station end reclosing judgment devices on two sides of the mixed line, and respectively collecting three-phase currents on the respective sides of the mixed line in real time by the station end reclosing judgment devices on the two sides;
step four, each acquisition unit sends the three-phase current of each installation point to a station end reclosing judgment device on two sides, and the station end reclosing judgment devices on two sides send the three-phase current on each side to a station end reclosing judgment device on the opposite side;
fifthly, judging section faults by the reclosing judging devices at the station ends at the two sides according to current data at the respective sides and the received current data, and outputting corresponding reclosing signals according to the section fault judging results.
The specific criterion of the reclosing judging device of the station ends at two sides for judging the fault of the section K (K is more than or equal to 1 and less than or equal to N) according to the current data of each side and the received current data is as follows:
judging that the section K has a fault when the differential current of the currents on the two sides of the section K is larger than a differential current fixed value; the specific formula of the differential criterion is as follows:
Figure RE-GDA0003305685760000041
phi is three-phase of A, B and C
Wherein: i isKdΦIn order to obtain a differential current in the section K,
Figure RE-GDA0003305685760000042
the amplitude of the vector sum of the currents on the two sides of the section K is obtained;
IKrΦbraking current for section K;
Figure RE-GDA0003305685760000043
the amplitude of the current vector difference on the two sides of the section K is obtained;
Idsetsetting the differential current;
IK1Φ、IK2Φrespectively are currents on two sides of the section K;
judging that the region K has a fault when the current on one side is greater than an overcurrent fixed value and the current on the other side is less than the overcurrent fixed value in the currents on the two sides of the region K; the specific formula of the overcurrent criterion is as follows:
Figure RE-GDA0003305685760000051
or
Figure RE-GDA0003305685760000052
Phi is three-phase of A, B and C
Wherein: i isK1Φ、IK2ΦRespectively are currents on two sides of the section K; i islsetSetting the value for overcurrent;
the first criterion and the second criterion are in an OR relationship, and if any one of the first criterion and the second criterion is satisfied, the fault of the area K is judged.
Specifically, the specific method for the reclosing judging device at the station ends on both sides to output the corresponding reclosing signal according to the section fault judging result is as follows:
when any cable section has a fault, the station end reclosing judging device outputs a reclosing signal;
when all cable sections have no faults, the station end reclosing criterion device does not output a reclosing signal.
The above-mentioned embodiments are merely illustrative of the inventive concept and are not intended to limit the scope of the invention, which is defined by the claims and the insubstantial modifications of the inventive concept can be made without departing from the scope of the invention.

Claims (4)

1. An intelligent reclosing method for an overhead line-cable hybrid line is characterized by comprising the following steps:
dividing a mixed line into N continuous sections according to an overhead line section and a cable section;
secondly, mounting an acquisition unit between every two adjacent sections, and acquiring the three-phase current of each mounting point in real time by each acquisition unit;
respectively installing station end reclosing judgment devices on two sides of the mixed line, and respectively collecting three-phase currents on the respective sides of the mixed line in real time by the station end reclosing judgment devices on the two sides;
step four, each acquisition unit respectively sends the three-phase current of each installation point to station end reclosing judging devices on two sides, and the station end reclosing judging devices on two sides send the three-phase current of each side to the station end reclosing judging device on the opposite side;
fifthly, judging section faults by reclosing judging devices at the station ends at two sides according to current data at the respective sides and the received current data, and outputting corresponding reclosing signals according to a section fault judging result, wherein the section fault judging comprises the following criteria:
judging that the section K has a fault when the differential current of the currents on the two sides of the section K is larger than a differential current fixed value;
judging that the region K has a fault when the current on one side is greater than an overcurrent fixed value and the current on the other side is less than the overcurrent fixed value in the currents on the two sides of the region K;
the first criterion and the second criterion are in an OR relationship, and if any one of the first criterion and the second criterion is satisfied, the region K is judged to have a fault, wherein K is more than or equal to 1 and less than or equal to N.
2. The intelligent reclosing method of an overhead line-cable hybrid line according to claim 1, wherein the specific method for the station-end reclosing decision devices on both sides to output the corresponding reclosing signal according to the section fault decision result is as follows:
when any cable section has a fault, the station end reclosing judging device outputs a reclosing signal;
when all cable sections have no faults, the station end reclosing criterion device does not output a reclosing signal.
3. The intelligent reclosing method of an overhead line-cable hybrid line according to claim 1, wherein the differential criterion is specifically defined as follows:
Figure RE-FDA0003305685750000021
phi is three phases of A, B and C;
wherein: i isKdΦIn order to obtain a differential current in the section K,
Figure RE-FDA0003305685750000022
the amplitude of the vector sum of the currents on the two sides of the section K is obtained;
IKrΦthe current is braked for the section K,
Figure RE-FDA0003305685750000023
the amplitude of the current vector difference on the two sides of the section K is obtained;
Idsetsetting the differential current;
IK1Φ、IK2Φrespectively, the current on both sides of the section K.
4. The intelligent reclosing method of an overhead line-cable hybrid line according to claim 1, wherein the overcurrent criterion is specifically defined as follows:
Figure RE-FDA0003305685750000024
phi is three phases of A, B and C;
wherein: i isK1Φ、IK2ΦRespectively are currents on two sides of the section K; i islsetThe value is determined for overcurrent.
CN202111035903.XA 2021-09-06 2021-09-06 Intelligent reclosing method for overhead line-cable hybrid line Pending CN113991597A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109709439A (en) * 2019-02-25 2019-05-03 南京南瑞继保电气有限公司 A kind of mixed line fault localization method based on joint acquisition unit
CN109782133A (en) * 2019-02-25 2019-05-21 南京南瑞继保电气有限公司 A kind of multistage cable-transmission line Fault Locating Method
CN113036726A (en) * 2021-02-26 2021-06-25 国网浙江省电力有限公司电力科学研究院 Cable-overhead hybrid line intelligence reclosing system based on 5G

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109709439A (en) * 2019-02-25 2019-05-03 南京南瑞继保电气有限公司 A kind of mixed line fault localization method based on joint acquisition unit
CN109782133A (en) * 2019-02-25 2019-05-21 南京南瑞继保电气有限公司 A kind of multistage cable-transmission line Fault Locating Method
CN113036726A (en) * 2021-02-26 2021-06-25 国网浙江省电力有限公司电力科学研究院 Cable-overhead hybrid line intelligence reclosing system based on 5G

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
屠强: "《现场运行人员继电保护知识实用技术与问答 第2版》", 中国电力出版社, pages: 233 *

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