CN117439023A - Underground cable fault protection method based on coordination of current relay and time sequence - Google Patents

Underground cable fault protection method based on coordination of current relay and time sequence Download PDF

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Publication number
CN117439023A
CN117439023A CN202311175324.4A CN202311175324A CN117439023A CN 117439023 A CN117439023 A CN 117439023A CN 202311175324 A CN202311175324 A CN 202311175324A CN 117439023 A CN117439023 A CN 117439023A
Authority
CN
China
Prior art keywords
fault
current relay
current
relay
time
Prior art date
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
CN202311175324.4A
Other languages
Chinese (zh)
Inventor
张建
陈军
吴昊
杨跃平
黄致远
曹松钱
焦阳
贝斌斌
林生津
张池川
朱正航
陈徐
钟邱龙
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ningbo Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
Original Assignee
Ningbo Power Supply Co of State Grid Zhejiang 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 Ningbo Power Supply Co of State Grid Zhejiang Electric Power Co Ltd filed Critical Ningbo Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
Priority to CN202311175324.4A priority Critical patent/CN117439023A/en
Publication of CN117439023A publication Critical patent/CN117439023A/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
    • 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
    • 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
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
    • 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
    • H02H3/021—Details concerning the disconnection itself, e.g. at a particular instant, particularly at zero value of current, disconnection in a predetermined order
    • 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
    • H02H7/261—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 involving signal transmission between at least two stations
    • H02H7/262—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 involving signal transmission between at least two stations involving transmissions of switching or blocking orders
    • 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
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses an underground cable fault protection method based on coordination of a current relay and a time sequence, in particular to the technical field of an underground power system, wherein a maximum fault current value, a minimum fault current value and corresponding action current are preset through the current relay according to the attribute of a breaker, when the maximum fault current value is larger than the minimum fault current value, a protection mode is entered according to a fault position, and when the fault current is larger than the action current, a cable fault position is circularly detected through a Newton analysis method according to a cable protocol model, the operation time and time dial settings of a main current relay and a standby current relay are calculated, the time dial settings are unchanged, and when the main current relay and the standby current relay do not reach the operation time, the protection mode is ended; the underground cable area can be detected more quickly through the coordination of the current relay and the time sequence, the fault section is identified, and the fault location is carried out, so that the efficiency of solving the fault of the underground cable is improved.

Description

Underground cable fault protection method based on coordination of current relay and time sequence
Technical Field
The invention relates to the technical field of underground power systems, in particular to an underground cable fault protection method based on coordination of a current relay and a time sequence.
Background
Faults in the power system can affect its reliability, safety and stability. Underground power systems are more complex and require higher accuracy in fault detection and localization to achieve optimal fault management. In fault detection and localization, slow processing speed and inability to coordinate protection areas using relays are alarming problems, as these problems can degrade the performance of the power protection system.
Among other things, a subsurface cable fault can have a variety of effects on the power system and associated equipment, depending on the nature, location, and duration of the fault. The most obvious effect is a power outage, which may result in a power outage in the affected area, which may affect the proper operation of residents, businesses and critical facilities. In underground cable fault detection, various problems are often caused by inaccurate positioning or slow detection speed.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to solve the technical problem of providing the underground cable fault protection method based on coordination of the current relay and the time sequence, which is used for solving the problem of slow underground cable fault detection in the prior art.
The technical scheme adopted for solving the technical problems is that the underground cable fault protection method based on coordination of a current relay and a time sequence is characterized by comprising the following steps:
s1, presetting a maximum fault current value, a minimum fault current value and corresponding action current through a current relay according to the attribute of a circuit breaker;
s2, when the maximum fault current value is larger than the minimum fault current value, performing fault detection on the underground cable through discrete wavelet transformation, selecting a protection mode according to the fault position, outputting a tripping instruction to the cable through a protection system, and performing original setting restoration operation;
s3, when a protection mode is entered and the fault current is larger than the action current, performing cyclic detection on a cable fault position through a Newton Lapherson analysis method according to a cable protocol model, and calculating the running time and time dial settings of the main current relay and the standby relay;
and S4, ending the protection mode when the time dial setting is unchanged and the main current relay and the standby relay do not reach the running time.
Further, the newton-raphson analysis method performs iterative detection and positioning according to cable short-circuit faults and load conditions.
Further, in the step S2, when the underground cable fails, the current relay current and the operation time are set to minimum values through the protection system.
Further, the protection mode only performs a protection procedure for the cable fault.
Further, in the step S4, when the main current relay does not reach the operation time, the protection system detects the operation time of the backup relay.
Further, newton-radson analysis operation is performed when the main current relay and the backup current relay reach run times.
Further, the standby current relay controls the operation sequence through the coordination logic.
Further, when the time dial setting is changed, the fault current and short-circuit current coordination value of the current relay is obtained through the system.
Further, relay coordination operation is performed through the main current relay, the standby relay running time and the time dial setting.
Further, the main current relay and the standby current relay are subjected to action time sequence control through the time dial.
Compared with the prior art, the invention has at least the following beneficial effects:
(1) According to the underground cable fault protection method based on coordination of the current relay and the time sequence, the off-current relay and the time sequence are used for coordination, so that the underground cable fault detection efficiency is improved.
Drawings
FIG. 1 is a flow chart of a method of underground cable fault protection based on current relay and timing coordination.
Detailed Description
The following are specific embodiments of the present invention and the technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.
Example 1
In order to solve the problem of slow fault detection of an underground cable, as shown in fig. 1, the invention relates to an underground cable fault protection method based on coordination of a current relay and a time sequence, which is characterized by comprising the following steps:
s1, presetting a maximum fault current value, a minimum fault current value and corresponding action current through a current relay according to the attribute of a circuit breaker;
s2, when the maximum fault current value is larger than the minimum fault current value, performing fault detection on the underground cable through discrete wavelet transformation, selecting a protection mode according to the fault position, outputting a tripping instruction to the cable through a protection system, and performing original setting restoration operation;
s3, when a protection mode is entered and the fault current is larger than the action current, performing cyclic detection on the cable fault position through a Newton Lapherson analysis method according to a cable protocol model, and calculating the running time and time dial settings of the main current relay and the standby current relay;
and S4, ending the protection mode when the time dial setting is unchanged and the main current relay and the standby current relay do not reach the running time.
In an electrical power system, network structure and performance parameters including voltage, current, resistance, reactance, etc. are first passed through an underground cable system. These parameters are recorded by voltage and current measurements for subsequent fault detection and localization, circuit breakers are key devices in the power system for isolating faults and protecting the system, maximum fault current values, minimum fault current values and corresponding action currents are preset by current relays according to the breaker attributes, and fault current values and time settings are preset for each relay. These settings depend on the plug and time settings of the relay to ensure that the relay is able to act in good time when a fault occurs, and when entering a protection mode, newton-radson analysis is performed and a determination is made as to whether a fault has occurred based on the actual short circuit fault and load conditions. The method is characterized in that the method comprises the steps of performing iterative detection and positioning according to cable short-circuit fault and load conditions, performing fault detection on an underground cable through discrete wavelet transformation when the maximum fault current value is larger than the minimum fault current value, selecting a proper protection mode according to the fault position, observing the arrangement in the power system, continuing to execute the next step, otherwise, not performing Newton analysis operation further, performing cyclic detection on the fault position of the cable through Newton analysis according to a cable protocol model when the fault current is larger than action current, calculating the running time and the time dial of a main current relay and a standby relay, setting the current relay and the running time to be the minimum values through a protection system, determining the fault position through analysis of the current and the time setting, so as to select the optimal protection mode, ensuring that only the fault part is selected, and the rest part of the power system is not influenced. The overcurrent relay is a device for detecting that a current exceeds a preset threshold, once a fault current reaches or exceeds an action current setting of the current relay, the current relay is operated, which usually only occurs after the fault occurs, not during normal operation, newton-radson analysis is performed according to a protocol model, so that an optimal operation state of a protection mode is realized, the current relay coordination needs to consider an operation time of the current relay to ensure coordination between a main relay and a standby relay, the main current relay is the current relay of a preferred action, the standby current relay acts when the main current relay fails, a time dial is used for determining the action time of the relay, the operation time of the relay needs to be recalculated when the time dial setting changes, then a system checks whether the main current relay is damaged, if the main current relay is normal, newton-radson analysis is performed to further detect the fault, and if the main current relay is damaged, the system observes the standby current relay to ensure that a cable is continuously protected. If the backup current relay is also damaged, the protection area may not continue to operate, and finally, the system may check whether the backup current relay is operating normally, if the backup current relay is operating normally, the system will perform newton-radson analysis to continue monitoring for faults, if the backup current relay is also not operating, the protection area may not continue to operate, and manual measures may be required to isolate cables or perform maintenance, thereby ending the protection mode for the protection area, ensuring that the power system can perform fault detection and maintenance when faults occur through the coordination of the current relay and the time sequence, so as to maintain the reliability and safety of the system.
Further, a main current relay and a standby current relay may be used in the power system. The main current relay is the current relay of the preferred action, and the standby current relay acts when the main current relay fails. Each current relay has an operating current setting indicating that the current relay will operate when the current exceeds the set point. This is the basic operating threshold of the current relay. A time delay may be set between the current relays, i.e. after the current reaches the action current setting, the current relays are allowed to act after waiting a period of time. This is to ensure that the main current relay has enough time to operate without immediately triggering the standby current relay. The current relay coordination timing also includes coordination logic, i.e., determining which current relay should act first and which should delay the action, which is typically determined based on the action current settings and timing delays. Current relay and timing coordination are one method of managing the operation of current relays in a power system, and are intended to ensure that in the event of a fault, the relays act in the correct sequence and timing to minimize the impact of the fault on the system and ensure the reliability and safety of the system.
In summary, according to the underground cable fault protection method based on coordination of the current relay and the time sequence, the maximum fault current value, the minimum fault current value and the corresponding action current are preset through the current relay according to the breaker attribute, when the maximum fault current value is larger than the minimum fault current value, fault detection is carried out on the underground cable through discrete wavelet transformation, a protection mode is selected according to the fault position, a tripping instruction is output to the cable through a protection system to restore original setting operation, when the protection mode is entered and the fault current is larger than the action current, the cable fault position is circularly detected through a Newton Lawson analysis method, the operation time and the time dial setting of the main current relay and the standby current relay are calculated, the time dial setting is unchanged, and when the main current relay and the standby current relay do not reach the operation time, the protection mode is ended; the underground cable area can be detected more quickly through the coordination of the current relay and the time sequence, the fault section is identified, and the fault location is carried out, so that the efficiency of solving the fault of the underground cable is improved.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
Furthermore, descriptions such as those referred to herein as "first," "second," "a," and the like are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or an implicit indication of the number of features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In addition, the technical solutions of the embodiments of the present invention may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the technical solutions, and when the technical solutions are contradictory or cannot be implemented, the combination of the technical solutions should be considered as not existing, and not falling within the scope of protection claimed by the present invention.

Claims (10)

1. The underground cable fault protection method based on the coordination of the current relay and the time sequence is characterized by comprising the following steps:
s1, presetting a maximum fault current value, a minimum fault current value and corresponding action current through a current relay according to the attribute of a circuit breaker;
s2, when the maximum fault current value is larger than the minimum fault current value, performing fault detection on the underground cable through discrete wavelet transformation, selecting a protection mode according to the fault position, outputting a tripping instruction to the cable through a protection system, and performing original setting restoration operation;
s3, when a protection mode is entered and the fault current is larger than the action current, performing cyclic detection on the cable fault position through a Newton Lapherson analysis method according to a cable protocol model, and calculating the running time and time dial settings of the main current relay and the standby current relay;
and S4, ending the protection mode when the time dial setting is unchanged and the main current relay and the standby current relay do not reach the running time.
2. The underground cable fault protection method based on coordination of a current relay and a time sequence according to claim 1, wherein the newton-raphson analysis method is used for iterative detection and positioning according to cable short-circuit fault and load conditions.
3. The method according to claim 1, wherein in the step S2, when the underground cable fails, the current relay current and the operation time are set to minimum values by the protection system.
4. The underground cable fault protection method based on the coordination of the current relay and the time sequence according to claim 1, wherein the protection mode only carries out protection program on the fault part of the cable.
5. The method according to claim 1, wherein in step S4, when the main current relay does not reach the operation time, the protection system detects the operation time of the standby current relay.
6. The method of claim 5, wherein newton's-on-analysis is performed when the main current relay and the backup current relay reach run time.
7. The underground cable fault protection method based on coordination of a current relay and a time sequence according to claim 6, wherein the standby current relay controls the operation sequence through a coordination logic.
8. The underground cable fault protection method based on the coordination of the current relay and the time sequence according to claim 1, wherein when the time dial setting is changed, fault current and short-circuit current coordination values of the current relay are obtained through a system.
9. The underground cable fault protection method based on the coordination of the current relay and the time sequence according to claim 1, wherein the relay coordination operation is carried out through the main current relay, the standby current relay operation time and the time dial setting.
10. The underground cable fault protection method based on the coordination of the current relay and the time sequence according to claim 9, wherein the time dial is used for controlling the action time sequence of the main current relay and the standby current relay.
CN202311175324.4A 2023-09-13 2023-09-13 Underground cable fault protection method based on coordination of current relay and time sequence Pending CN117439023A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311175324.4A CN117439023A (en) 2023-09-13 2023-09-13 Underground cable fault protection method based on coordination of current relay and time sequence

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311175324.4A CN117439023A (en) 2023-09-13 2023-09-13 Underground cable fault protection method based on coordination of current relay and time sequence

Publications (1)

Publication Number Publication Date
CN117439023A true CN117439023A (en) 2024-01-23

Family

ID=89556005

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311175324.4A Pending CN117439023A (en) 2023-09-13 2023-09-13 Underground cable fault protection method based on coordination of current relay and time sequence

Country Status (1)

Country Link
CN (1) CN117439023A (en)

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