CN116365496A - Method for selecting high-voltage single-core cable sheath protector - Google Patents

Method for selecting high-voltage single-core cable sheath protector Download PDF

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Publication number
CN116365496A
CN116365496A CN202310208813.9A CN202310208813A CN116365496A CN 116365496 A CN116365496 A CN 116365496A CN 202310208813 A CN202310208813 A CN 202310208813A CN 116365496 A CN116365496 A CN 116365496A
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sheath
cable
power frequency
protector
voltage
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Inventor
郑建康
苏小婷
徐阳
胡钰骁
李庚�
蒲路
盛玉倩
梁战伟
王瀚锋
李少斌
倪娜
康健
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State Grid Shaanxi Electric Power Co Ltd Xi'an Power Supply Co
Xian Jiaotong University
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State Grid Shaanxi Electric Power Co Ltd Xi'an Power Supply Co
Xian Jiaotong University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • 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
    • H02H7/22—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 for distribution gear, e.g. bus-bar systems; for switching devices
    • H02H7/226—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 for distribution gear, e.g. bus-bar systems; for switching devices for wires or cables, e.g. heating wires
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/16—Cables, cable trees or wire harnesses
    • 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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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Evolutionary Computation (AREA)
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  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a method for selecting a high-voltage single-core cable sheath protector, which comprises the following steps: calculating the maximum power frequency overvoltage of the cable sheath during short circuit fault; comparing the maximum power frequency overvoltage of the cable sheath with the power frequency withstand voltage of the cable outer sheath, and selecting whether the maximum power frequency overvoltage of the cable sheath is limited or not; determining the residual voltage of the sheath protector and the upper limit U of rated voltage according to the lightning impulse insulation level and the lead voltage drop of the cable outer sheath r1 Determining the lower limit U of rated voltage according to the power frequency tolerance time characteristic of the protective layer protector r2 If U r1 ＜U r2 The maximum power frequency overvoltage of the cable sheath is still limited; otherwise, selecting the protective layer protector according to the rated voltage of the protective layer protector; energy absorption during transient impact of selected sheath protectorAnd checking, wherein if the checking does not reach the standard, the rated voltage of the protective layer protector is improved within the range of the upper limit and the lower limit of the rated voltage of the protective layer protector so as to meet the requirement of energy absorption.

Description

Method for selecting high-voltage single-core cable sheath protector
Technical Field
The disclosure belongs to the technical field of power transmission and transformation, and mainly relates to a method for selecting a high-voltage single-core cable sheath protector.
Background
With the influence of overhead lines on urban appearance, overhead line ground entering projects are widely developed, so that high-voltage power cables become an important component of urban power transmission systems. The problem of metal sheath induced voltage exists in 110kV and above high-voltage single-core power cables generally, when a cable head or an overhead line connected with the cable head or the overhead line is in short circuit fault, induced overvoltage with very high amplitude can be generated on the cable sheath, the outer sheath is exposed to the outermost side for a long time, breakdown voltage is much smaller than that of main insulation, and stable operation of the cable is endangered by the higher induced voltage.
In order to prevent the outer sheath and the intermediate joint of the cable body from breakdown and damage due to excessive transient surge voltage, a protection device for limiting the surge voltage, namely a sheath protector, is usually arranged at the insulated joint. However, the breakdown damage of the outer sheath and the sheath protector frequently occurs, and is most common in the cable section of the overhead line and cable hybrid line. The design of the current sheath grounding system is mainly characterized in that the problems exist in sheath voltage calculation and accessory selection, firstly, the power frequency overvoltage of the cable section sheath of the overhead line and the cable mixed line is greatly influenced by the ground potential rise of the connection point of the two lines, and the numerical value can far exceed the power frequency withstand voltage value of the outer sheath, but the ground potential rise cannot be calculated by the current manual calculation value, so that the calculated value of the sheath voltage is lower and the calculation is carried out by means of electromagnetic transient simulation; on the other hand, when the power frequency overvoltage of the outer protective layer exceeds the insulation level, the protective layer voltage must be limited by methods such as laying a return line and reducing the grounding resistance, and the like, instead of relying on the action of the protector, the fact proves that the protector breaks down due to the fact that the power frequency voltage with the two ends being too high and the energy absorption capacity are insufficient, and the protector is taken as a sub-class of a lightning arrester, and the protector should reliably act during operation and lightning impulse, but the protector should bear rather than act under the power frequency overvoltage, and at present, some misunderstanding exists in the selection of the protective layer protector.
It can be seen that the existing selection of the sheath protector has problems, so that the frequent breakdown failure of the outer sheath and the sheath protector of the cable is caused, and therefore, the maximum power frequency overvoltage of the outer sheath needs to be reasonably limited, and the parameter selection of the sheath protector is clarified, which has positive influence on the safe and stable operation of the power cable line.
Disclosure of Invention
Aiming at the defects in the prior art, the purpose of the present disclosure is to provide a method for selecting a high-voltage single-core cable sheath protector, which can effectively protect the outer sheath of a high-voltage cable and the stable operation of the sheath protector.
In order to achieve the above object, the present disclosure provides the following technical solutions:
a method for selecting a high-voltage single-core sheath protector comprises the following steps:
s100: calculating the maximum power frequency overvoltage U of the cable sheath during short circuit fault TOV ；
S200: comparing the maximum power frequency overvoltage of the cable sheath with the power frequency withstand voltage of the cable outer sheath, and if the comparison result is smaller than a threshold value, executing the step S300; otherwise, the maximum power frequency overvoltage U of the cable sheath is needed TOV Limiting;
s300: determining residual voltage U of sheath protector according to lightning impulse insulation level and lead voltage drop of cable outer sheath res Upper limit U of rated voltage r1 And determining the lower limit U of rated voltage according to the power frequency tolerance time characteristic of the protective layer protector r2 If U r1 ＜U r2 Limiting the maximum power frequency overvoltage of the cable sheath; otherwise, selecting the protective layer protector according to the rated voltage of the protective layer protector;
s400: and checking the energy absorption of the selected protective layer protector during transient impact, and if the checking does not reach the standard, improving the rated voltage of the protective layer protector in a section defined by the upper limit and the lower limit of the rated voltage of the protective layer protector so as to meet the requirement of energy absorption.
Preferably, in step S100, any electromagnetic transient simulation software including ATP-EMTP and PSCAD-EMTDC is used to calculate the maximum power frequency overvoltage of the cable sheath in the event of a short circuit fault.
Preferably, in step S200, the maximum power frequency overvoltage of the cable sheath is compared with the power frequency withstand voltage of the cable outer sheath by the following formula:
Figure BDA0004111843570000031
wherein U is TOV Indicating the maximum power frequency overvoltage of the cable sheath, U dc withstand Represents the direct-current withstand voltage of the outer sheath of the cable,
Figure BDA0004111843570000032
the power frequency withstand voltage of the cable outer sheath is represented, and 1.15 represents a margin coefficient.
Preferably, in step S200, limiting the maximum power frequency overvoltage of the cable sheath includes any one of the following modes: laying a return line; reducing the grounding resistance of the cable along the line; the wiring mode of the protective layer protector is changed from star wiring to triangle wiring.
Preferably, in step S300, the lower limit value U of the rated voltage of the cable sheath protector r2 The following should be satisfied:
Figure BDA0004111843570000033
wherein T is r2s The rated voltage multiple corresponding to the power frequency tolerance time characteristic curve 2s of the protective layer protector.
Preferably, in step S300, the residual voltage U of the sheath protector res Superimposed value E with lead voltage drop b The lightning impulse withstand voltage value of the cable outer sheath is not more than 1.4, and the residual voltage U of the sheath protector is confirmed by the following formula res Upper limit of rated voltage U proportional thereto r1 The method comprises the following steps:
Figure BDA0004111843570000041
Figure BDA0004111843570000042
U r1 ∝U res
wherein L is b The unit is mu H/m; l is the length of the lead, and the unit is m; i and τ are the impact current magnitudes (taken
Figure BDA0004111843570000043
) And the wave head time is respectively in the units of kA and mu s; BIL is the lightning impulse tolerance level of the main insulation of the cable, and the unit is kV; z1 is the cable wave impedance in Ω.
Preferably, in step S400, the energy absorption of the sheath protector at the time of transient impact is checked by:
Figure BDA0004111843570000044
wherein U is s For the expected sheath overvoltage, the unit is kV; t is the impact current duration, taking t=21/v in ms;1 is the length of a line, and the unit is km; v is the wave velocity in the cable, and the unit is km/ms; z is the wave impedance of the cable in omega.
The present disclosure also provides a computer device comprising:
a memory and a processor, wherein,
the memory has stored thereon an executable program executable on the processor;
the processor executes the executable program to implement any of the methods described previously.
Compared with the prior art, the beneficial effects that this disclosure brought are:
1. when the sheath protector is selected, the power frequency overvoltage of the sheath needs to be calculated, and meanwhile, whether the power frequency overvoltage exceeds the power frequency withstand voltage value of the outer sheath of the cable is checked, so that the breakdown of the outer sheath is prevented;
2. the sheath protector is a protective device of the cable outer sheath, can be used correctly to ensure reliable action during impact, and limits the sheath impact voltage within the impact withstand voltage value.
Drawings
FIG. 1 is a flow chart of a method for selecting a high voltage single core cable sheath protector according to one embodiment of the present disclosure;
fig. 2 is a schematic diagram of a power frequency tolerance time characteristic of a sheath protector according to another embodiment of the present disclosure.
Detailed Description
Specific embodiments of the present disclosure will be described in detail below with reference to fig. 1 to 2. While specific embodiments of the disclosure are shown in the drawings, it should be understood that the disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
It should be noted that certain terms are used throughout the description and claims to refer to particular components. Those of skill in the art will understand that a person may refer to the same component by different names. The specification and claims do not identify differences in terms of components, but rather differences in terms of the functionality of the components. As used throughout the specification and claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The description hereinafter sets forth the preferred embodiments for carrying out the present disclosure, but is not intended to limit the scope of the disclosure in general, as the description proceeds. The scope of the present disclosure is defined by the appended claims.
For the purposes of promoting an understanding of the embodiments of the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific examples, without the intention of being limiting the embodiments of the disclosure.
In one embodiment, as shown in fig. 1, the disclosure provides a method for selecting a high-voltage single-core cable sheath protector, which includes the following steps:
s100: calculating the maximum power frequency overvoltage U of the cable sheath during short circuit fault TOV ；
In the step, electromagnetic transient simulation software ATP-EMTP or PSCAD-EMTDC is adopted to calculate the maximum power frequency overvoltage of the cable sheath when a short circuit fault occurs.
In this embodiment, for a pure cable line, the maximum power frequency overvoltage U of the cable sheath generated by the short-circuit fault at the cable end needs to be calculated TOV The method comprises the steps of carrying out a first treatment on the surface of the For the mixed line of the overhead line and the cable, the overvoltage of the protective layer under the two conditions of the side short circuit of the overhead line and the short circuit of the tail end of the cable is calculated, and a larger value is taken as U TOV 。
It should be noted that, the short-circuit fault described in this embodiment is a fault occurring at the cable terminal and the outside, and does not include an internal fault of the cable system, for example, an internal short-circuit between the core and the sheath caused by main insulation breakdown of the cable, in this case, a power frequency overvoltage with extremely high amplitude will be generated, and the sheath protector will be broken down and even thermally broken down.
S200: comparing the maximum power frequency overvoltage of the cable sheath with the power frequency withstand voltage of the cable outer sheath, and if the comparison result is smaller than a threshold value, executing the step S300; otherwise, the cable sheath is required to be subjected to maximum power frequency overvoltage U TOV Limiting;
in the step, the maximum power frequency overvoltage of the cable sheath is compared with the power frequency withstand voltage of the cable outer sheath by the following formula:
Figure BDA0004111843570000071
wherein U is TOV Indicating the maximum power frequency overvoltage of the cable sheath, U de withstand Represents the direct-current withstand voltage of the outer sheath of the cable,
Figure BDA0004111843570000072
the power frequency withstand voltage of the cable outer sheath is represented, and 1.15 represents a margin coefficient.
In this embodiment, if the above relation is not satisfied between the maximum power frequency overvoltage of the cable sheath and the power frequency withstand voltage of the cable outer sheath, on one hand, the risk of breakdown of the cable outer sheath during short circuit is present, and on the other hand, when the sheath protector satisfies the insulation matching condition under impact, the short circuit condition cannot be achievedLower power frequency tolerance, lowering the ground resistance of the cable along the line by laying a return wire, and connecting the protective layer protector from a star connection (i.e. Y 0 The wiring) is changed to a delta wiring (i.e., delta wiring).
S300: determining residual voltage U of sheath protector according to lightning impulse insulation level and lead voltage drop of cable outer sheath res Upper limit U of rated voltage r1 And determining the lower limit U of rated voltage according to the power frequency tolerance time characteristic of the protective layer protector r2 If U r1 ＜U r2 Limiting the maximum power frequency overvoltage of the cable sheath; otherwise, selecting the protective layer protector according to the rated voltage of the protective layer protector;
in this step, the lightning impulse withstand voltage U of the cable sheath LW The values are shown in table 1. Residual voltage U of protective layer protector under standard discharge current (generally 8/20 mu s,10 kA) res Superimposed value E with lead voltage drop b The lightning impulse withstand voltage value of the cable outer sheath is not more than 1.4, and the residual voltage U of the sheath protector is confirmed by the following method res Upper limit of rated voltage U proportional thereto r1 The method comprises the following steps:
Figure BDA0004111843570000081
Figure BDA0004111843570000082
U r1 ∝U reS
wherein L is b The unit is mu H/m; l is the length of the lead, and the unit is m; i and τ are the impact current magnitudes (taken
Figure BDA0004111843570000083
) And the wave head time is respectively in the units of kA and mu s; BIL is the lightning impulse tolerance level of the main insulation of the cable, and the unit is kV; z is Z 1 The wave impedance of the cable is shown as omega.
TABLE 1 lightning impulse withstand voltage values of cable outer sheath
Figure BDA0004111843570000084
The upper limit of the residual voltage of the selected protective layer protector can be determined through the method, and the upper limit U of the rated voltage can be determined because the residual voltage of the ZnO valve plate is changed in proportion to the 2s power frequency withstand voltage rI 。
The power frequency tolerance of the cable sheath protector under short circuit fault is the most basic requirement for selection. The manufacturer needs to give the industrial frequency tolerance time characteristic (TOV characteristic) of the protective layer protector which is not damaged or thermally collapsed after being preheated to 60+/-3 ℃ and loaded by high current energy, as shown in figure 2, and reads the corresponding value T of 2s r2s The margin is 5-25%, the rated voltage of the protective layer protector meets the following formula, so that the lower limit U of the rated voltage is determined r2 ：
Figure BDA0004111843570000091
Further, if U r1 ＜U r2 The measures for reducing the maximum power frequency overvoltage of the cable sheath are still needed to meet the basic requirements of power frequency tolerance and insulation fit selected by the sheath protector. If U is r1 ≥U r2 And selecting the final protective layer protector by taking the rated voltage as a parameter.
S400: and checking the energy absorption of the selected protective layer protector during transient impact, and if the checking does not reach the standard, improving the rated voltage of the protective layer protector in a section defined by the upper limit and the lower limit of the rated voltage of the protective layer protector so as to meet the requirement of energy absorption.
In this step, it is checked whether the energy absorbed by the sheath protector under transient impact such as lightning and operation exceeds its energy absorbing capacity, and in most cases the energy absorbing capacity is not a determining factor for the sheath protector to choose from, because the energy absorbed during a transient impact (duration in microseconds) is typically much lower than its energy absorbing capacity. However, for the case of a residual charge closing, electromagnetic transient simulations or verification of the energy absorption of the sheath protector according to the following equation are recommended.
The energy W of the sheath protector absorption operation or lightning overvoltage can be estimated as follows:
Figure BDA0004111843570000092
wherein U is s For the expected sheath overvoltage, the unit is kV; t is the duration of the impact current, taking t=2l/v in ms;1 is the length of a line, and the unit is km; v is the wave velocity in the cable in km/ms.
In the following, taking a certain overhead line and a cable mixed line (overhead line-cable-overhead line) as an example, the cable section adopts sheath cross interconnection and single-end grounding mixing.
(1) Calculating power frequency overvoltage of cable sheath during short circuit fault
The ATP-EMTP or PSCAD-EMTDC simulation cable is adopted, single-phase grounding short circuit faults occur at the terminals at two sides (overhead lines at two connected sides), and the maximum power frequency overvoltage (effective value) of the cable sheath is obtained: a single-phase grounding section 7.571kV; and the cross-connection section 11.433kV.
(2) Judging whether the outer protective layer meets the power frequency tolerance
Figure BDA0004111843570000101
Meets the requirements
(3) Ensuring power frequency tolerance during protector shorts
Taking T r2s =1.2, then single-ended ground:
Figure BDA0004111843570000102
cross-connect section:
Figure BDA0004111843570000103
(4) Meet the insulation fit of the sheath protector and the cable outer sheath
For a protector with rated voltage of 10kV, taking the lightning impulse withstand voltage U of which the front time is 1.2 mu s and the cable outer sheath LW 62.5kV
Figure BDA0004111843570000104
(5) Estimating energy absorption of a sheath protector during transient impacts
The energy absorbed in the transient impact process is far lower than the energy absorbing capacity under most conditions, and the ultrahigh voltage line adopts single-phase reclosing, so that the situation of closing with residual charges does not exist, and verification can be avoided.
With the above examples, the following can be concluded:
rated voltage U can be selected for the single-end grounding section of the protective layer r Sheath protector of =8 kV;
rated voltage U can be selected for the intersecting interconnection section of the protective layers r Sheath protector of 10 kV.
In another embodiment, the present disclosure also provides a computer device comprising:
a memory and a processor, wherein,
the memory has stored thereon an executable program executable on the processor;
the processor executes the executable program to implement any of the methods described previously.
The foregoing has outlined rather broadly the principles and embodiments of the present disclosure using specific examples that are presented herein to aid in the understanding of the methods of the present disclosure and the core concepts thereof; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in light of the ideas of the present disclosure, the present disclosure should not be construed as being limited to the above description.

Claims (8)

1. A method for selecting a high-voltage single-core cable sheath protector comprises the following steps:
s100: calculating the maximum power frequency overvoltage U of the cable sheath during short circuit fault TOV ；
S200: comparing the maximum power frequency overvoltage of the cable sheath with the power frequency withstand voltage of the cable outer sheath, and if the comparison result is smaller than a threshold value, executing the step S300; otherwise, the maximum power frequency overvoltage U of the cable sheath is needed TOV Limiting;
s300: determining residual voltage U of sheath protector according to lightning impulse insulation level and lead voltage drop of cable outer sheath res Upper limit U of rated voltage r1 And determining the lower limit U of rated voltage according to the power frequency tolerance time characteristic of the protective layer protector r2 If U r1 ＜U r2 Limiting the maximum power frequency overvoltage of the cable sheath; otherwise, selecting the protective layer protector according to the rated voltage of the protective layer protector;
s400: and checking the energy absorption of the selected protective layer protector during transient impact, and if the checking does not reach the standard, improving the rated voltage of the protective layer protector in a section defined by the upper limit and the lower limit of the rated voltage of the protective layer protector so as to meet the requirement of energy absorption.
2. The method according to claim 1, wherein in step S100, the maximum power frequency overvoltage of the cable sheath at the time of the short-circuit fault is preferably calculated by using any electromagnetic transient simulation software including ATP-EMTP and PSCAD-EMTDC.
3. The method of claim 1, wherein in step S200, the cable sheath maximum power frequency overvoltage is compared with the cable outer sheath power frequency withstand voltage by:
Figure FDA0004111843520000011
wherein U is TOV Indicating the maximum power frequency overvoltage of the cable sheath, U dc withstand Indicating the straight of the outer sheath of the cableThe current is subjected to a voltage which is a function of the current,
Figure FDA0004111843520000021
the power frequency withstand voltage of the cable outer sheath is represented, and 1.15 represents a margin coefficient.
4. The method of claim 1, wherein limiting the maximum power frequency overvoltage of the cable sheath in step S200 includes any one of: laying a return line; reducing the grounding resistance of the cable along the line; the wiring mode of the protective layer protector is changed from star wiring to triangle wiring.
5. The method of claim 1, wherein in step S300, the lower limit value U of the rated voltage of the sheath protector r2 The following should be satisfied:
Figure FDA0004111843520000022
wherein T is r2s The rated voltage multiple corresponding to the power frequency tolerance time characteristic curve 2s of the protective layer protector.
6. The method of claim 1, wherein in step S300, the residual pressure U of the sheath protector res Superimposed value E with lead voltage drop b A lightning impulse withstand voltage value U not greater than that of the cable outer sheath LW The residual voltage U of the sheath protector was confirmed by the following value divided by 1.4 res Upper limit of rated voltage U proportional thereto r1 The method comprises the following steps:
Figure FDA0004111843520000023
Figure FDA0004111843520000024
U r1 ∝U res
wherein L is b The unit is mu H/m; l is the length of the lead, and the unit is m; i and τ are the impact current magnitudes (taken
Figure FDA0004111843520000031
) And the wave head time is respectively in the units of kA and mu s; BIL is the lightning impulse tolerance level of the main insulation of the cable, and the unit is kV; z is Z 1 The wave impedance of the cable is shown as omega.
7. The method of claim 1, wherein in step S400, the energy absorption of the sheath protector at the time of a transient impact is checked by:
Figure FDA0004111843520000032
wherein U is s For the expected sheath overvoltage, the unit is kV; t is the duration of the impact current, taking t=2l/v in ms; l is the length of the line, and the unit is km; v is the wave velocity in the cable, and the unit is km/ms; z is the wave impedance of the cable in omega.
8. A computer device, comprising:
a memory and a processor, wherein,
the memory has stored thereon an executable program executable on the processor;
the processor executes the executable program to implement the method of any one of claims 1-6.
CN202310208813.9A 2022-03-07 2023-03-07 Method for selecting high-voltage single-core cable sheath protector Pending CN116365496A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116544895A (en) * 2023-07-06 2023-08-04 广东电网有限责任公司汕尾供电局 Pumped storage power station cable sheath fault grading protection method based on induced parameters

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116544895A (en) * 2023-07-06 2023-08-04 广东电网有限责任公司汕尾供电局 Pumped storage power station cable sheath fault grading protection method based on induced parameters
CN116544895B (en) * 2023-07-06 2023-10-20 广东电网有限责任公司汕尾供电局 Pumped storage power station cable sheath fault grading protection method based on induced parameters

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