CN112946521A - Power distribution network cable leakage current online detection method and insulation state monitoring method - Google Patents
Power distribution network cable leakage current online detection method and insulation state monitoring method Download PDFInfo
- Publication number
- CN112946521A CN112946521A CN202110159263.7A CN202110159263A CN112946521A CN 112946521 A CN112946521 A CN 112946521A CN 202110159263 A CN202110159263 A CN 202110159263A CN 112946521 A CN112946521 A CN 112946521A
- Authority
- CN
- China
- Prior art keywords
- cable
- current
- leakage current
- amplitude
- phase
- 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
Links
- 238000009413 insulation Methods 0.000 title claims abstract description 48
- 238000001514 detection method Methods 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 title claims abstract description 15
- 238000012544 monitoring process Methods 0.000 title claims abstract description 12
- 230000032683 aging Effects 0.000 claims abstract description 15
- 238000005070 sampling Methods 0.000 claims abstract description 14
- 238000012360 testing method Methods 0.000 claims abstract description 4
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 238000004364 calculation method Methods 0.000 claims description 5
- 238000011156 evaluation Methods 0.000 abstract description 2
- 229920003020 cross-linked polyethylene Polymers 0.000 description 6
- 239000004703 cross-linked polyethylene Substances 0.000 description 6
- 238000005259 measurement Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004422 calculation algorithm Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
Images
Classifications
-
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
- G01R15/202—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices
-
- 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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
-
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The invention discloses a power distribution network cable leakage current online detection method and an insulation state monitoring method, which are used for synchronously sampling currents at two ends of a cable to be detected to obtain current parameters including amplitude and phase at the same moment at the two ends of the cable to be detected; calculating the amplitude of the leakage current:
Δ I denotes the leakage current amplitude, I1Representing the current amplitude, I, of one end of the cable to be tested2Representing the current amplitude, theta, at the other end of the cable to be tested1Representing the phase of the current across the cable under test. The leakage current amplitude of each phase of cable is calculated by adopting the online detection method for the leakage current of the power distribution network cable, and the insulation aging state of each phase of cable is correspondingly evaluated according to the variation trend of the leakage current amplitude of each phase of cable: with the increase of the amplitude of the leakage current, the insulation aging degree of the cable is increased. According to the invention, the aging degree, local damage and other faults of the cable can be accurately reflected through the change trend of the leakage current, so that the accuracy of on-line monitoring and insulation state evaluation of the cable is improved.
Description
Technical Field
The invention belongs to the technical field of power transmission and distribution of a power system, and particularly relates to an online detection method and an insulation state monitoring method for leakage current of a power distribution network cable.
Background
Distribution network power cable insulation state detection is a powerful method for ensuring the safe operation of a distribution network. In order to realize early warning of potential faults of the power cable, researchers design a cable insulation state online monitoring method for sensing state information of cable insulation. The state information plays an indispensable role in the protection, operation and maintenance of the power distribution network and the management of equipment assets. When the cable is electrified and operated, partial discharge or insulation resistance reduction and other phenomena can be generated due to insulation damage, so that the insulation state of the cable can be obtained by measuring the insulation resistance and the partial discharge quantity of the cable. Relevant studies have been carried out by scholars at home and abroad, such as the following published documents:
[1] zhangyechi, tomaying, wang chongzheng, wang yue No. XLPE cable insulation detection simulation research based on dc superposition method [ J ] agricultural science and technology and equipment, 2016 (05): 33-34.
[2] Chen Hui, Zhang Wei, Ma Xinghe, research on a mining high-voltage cable signal denoising algorithm based on a partial discharge method [ J ]. energy and environmental protection, 2020, 42 (11): 130-133.
Document [1] adopts a direct current superposition method to evaluate the insulation state of a cable, and injects a direct current voltage into the cable, and filters an alternating current component by using a filter to obtain a weak direct current of an insulation layer caused by the injection of a direct current low voltage, so as to obtain the current insulation impedance of the cable, and the insulation state is evaluated by taking the size of the insulation impedance as a judgment basis. The characteristic signal direct current is usually nano-ampere level and is very weak, and in addition, a large measurement error is caused due to the existence of a large stray current. Document [2] uses a partial discharge method to evaluate the insulation state. When the inside of the cable insulation is degraded, a partial discharge phenomenon occurs, and the partial discharge amount of the cable is detected by means of adding high voltage to the cable insulation and the like, so that the insulation condition of the cable is judged. However, the voltage level of the distribution network is low, and the discharge signal of the partial discharge of the cable of the distribution network is extremely easy to be submerged by background noise, so that the method has quite high requirements on the accuracy of a sensor for detecting the partial discharge signal on site, the signal-to-noise ratio of on-site operation monitoring is low, and the method is not beneficial to popularization and use in actual engineering.
Disclosure of Invention
Aiming at the defects of the technology, the invention provides the online detection method for the leakage current of the power distribution network cable, which can accurately measure the leakage current, thereby laying a foundation for judging insulation aging.
In order to solve the technical problem, the online detection method for the leakage current of the power distribution network cable comprises the following steps:
synchronously sampling the current at two ends of the cable to be tested to obtain current parameters including amplitude and phase at the same moment at the two ends of the cable to be tested;
calculating the leakage current amplitude according to the following formula:
in the formula, Δ I represents the leakage current amplitude, I1Representing the current amplitude, I, of one end of the cable to be tested2Representing the current amplitude, theta, at the other end of the cable to be tested1Indicating the phase of the current, theta, at one end of the cable to be tested2Representing the current phase at the other end of the cable under test.
Further, the current at the two ends of the cable to be tested is collected in the following mode: the sampling current of the cable to be detected is obtained through the current transformer, the sampling current is converted into a voltage signal through the Hall current sensor and then is output to the analog-digital conversion circuit, and the voltage signal is converted into a digital signal by the analog-digital conversion circuit and then is output to the controller for calculation so as to obtain a current parameter.
The invention also provides a method for monitoring the cable insulation state of the power distribution network, which comprises the following steps: the leakage current amplitude of each phase of cable is calculated by adopting the online detection method for the leakage current of the power distribution network cable, and the insulation aging state of each phase of cable is correspondingly evaluated according to the variation trend of the leakage current amplitude of each phase of cable: with the increase of the amplitude of the leakage current, the insulation aging degree of the cable is increased.
Compared with the prior art, the invention has the advantages that:
1. the leakage current detection method provided by the invention is based on the current parameters at the same moment at the two ends of the cable, and can simply and accurately calculate the leakage current amplitude, thereby laying a foundation for judging insulation aging.
2. The invention combines the current transformer and the Hall current sensor to obtain the sampling signal, thereby having the milliampere-grade high-precision distinguishing capability and improving the accuracy of detecting the leakage current.
3. In the prior art, the insulation resistance or the partial discharge capacity is adopted to evaluate the insulation aging state of the cable, the leakage current amplitude is innovatively adopted as an index to evaluate the insulation aging state of the cable, and the change trend of the leakage current amplitude can accurately reflect the cable aging degree, partial damage and other faults, so that the accuracy of the online monitoring and insulation state evaluation of the cable is improved.
Drawings
Fig. 1 is a schematic diagram of an online detection method for leakage current of a power distribution network cable.
Fig. 2 shows the measured leakage current values for different lengths of 10.5kV crosslinked polyethylene cable.
Detailed Description
The following detailed description of specific embodiments of the invention refers to the accompanying drawings.
The invention can accurately detect the leakage current of the cables with different lengths on line, and can effectively evaluate the insulation state of the cables by combining the amplitude of the leakage current. The principle is that when the cable is electrified to operate, current flows through the insulating layer of the cable, and the current is leakage current of the cable. With the increase of the insulation aging degree of the cable, the main insulation of the cable shows the tendency of gradual reduction of insulation resistance and gradual increase of distributed capacitance, so that the leakage current is gradually increased. Therefore, the change trend of the leakage current can be obtained by monitoring the leakage current of the cable on line, and the change trend is used as the basis of the insulation aging of the cable. Specifically, the amplitude and the phase of three-phase current flowing through two ends of the cable are synchronously detected, the leakage current amplitude of the cable is obtained through calculation, and the insulation state of the cable is evaluated according to the variation trend of the leakage current amplitude.
For each phase cable in the distribution network, the same method is used to detect leakage current: synchronously collecting the current at two ends of the cable to be detected to obtain current parameters including amplitude and phase at the same moment at the two ends of the cable to be detected;
calculating the leakage current amplitude according to the following formula:
in the formula, Δ I represents the leakage current amplitude, I1Representing the current amplitude, I, of one end of the cable to be tested2Representing the current amplitude, theta, at the other end of the cable to be tested1Indicating the phase of the current, theta, at one end of the cable to be tested2Representing the current phase at the other end of the cable under test.
Leakage current amplitude delta I of cable A phase, B phase and C phaseA、ΔIBAnd Δ ICThe calculation formula is as follows:
where subscripts A, B and C are cable phase a, phase B, and phase C, respectively. Subscripts 1 and 2 are the two ends of the cable to be tested, respectively.
In order to improve the sampling precision, the currents at two ends of the cable to be detected are acquired in the following modes: referring to fig. 1, a current transformer is used to obtain a sampling current of a cable to be measured, the sampling current is converted into a voltage signal by a hall current sensor and then output to an analog-to-digital conversion circuit, and the voltage signal is converted into a digital signal by the analog-to-digital conversion circuit and then output to a controller for calculation to obtain a current parameter.
In order to improve the simultaneity of the current parameters, the controller packs and uploads the current parameters and the sampling time to the server, so that the server can judge whether the current parameters are the current parameters of the two ends of the cable to be tested at the same time or not through the sampling time. In addition, the controllers at the two ends of the cable can communicate with each other to transmit time information to each other, so that the time is unified. The time of the controllers at the two ends of the cable can be uniformly calibrated through the server.
The following crosslinked polyethylene cable (type: YJV 22-3X 400 mm) was crosslinked at 10.5kV2) The insulation state monitoring at different lengths is explained as an example.
FIG. 2 shows a 10.5kV crosslinked polyethylene cable (model: YJV 22-3X 400 mm)2) Leakage current measurements at different lengths. In the figure C0And CiRespectively equivalent distributed capacitance when the insulation state of the crosslinked polyethylene power cable is good and under the aging of the insulation state, wherein l is the length of the cable, and Delta I is the distributed capacitance CiAre respectively C0、1.05C0、1.1C0、1.2C0And 1.3C0And detecting the leakage current amplitude under different cable lengths l. The detection result of the leakage current delta I is consistent with the actual value, and the measurement precision is high.
According to FIG. 2, a 10.5kV crosslinked polyethylene cable (model: YJV 22-3X 400 mm)2) The change trend of the leakage current measurement values under different lengths can be known, the leakage current delta I is gradually increased along with the increase of the length l of the cable, and in addition, when the cable is aged in insulation, the distributed capacitance C isiAnd the detected leakage current delta I is correspondingly increased at the moment, and the amplitude of the delta I changing along with the delta I is increased along with the increasing aging degree of the cable, namely the detected delta I is larger.
In fig. 2, when l is 1500m, Δ I is 1086.1mA when the cable insulation degree is good, and when the distributed capacitance is increased by 5%, 10%, 20%, 30%, respectively, the detected leakage current Δ I is 1140.4mA, 1194.7mA, 1300.3mA, 1411.9mA, respectively. The current has large variation trend and is easy to distinguish. Therefore, the insulation state of the power distribution network cable can be effectively evaluated by combining the detected magnitude of the leakage current delta I of the cable.
In conclusion, the online detection method for the leakage current of the power distribution network cable can accurately detect the leakage current of the power distribution network cable, and can accurately provide early warning for potential faults of the power distribution network cable by further combining the amplitude variation trend of the leakage current of the power distribution network cable.
Finally, it should be noted that the above-mentioned examples of the present invention are only examples for illustrating the present invention, and are not intended to limit the embodiments of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it will be apparent to those skilled in the art that other variations and modifications can be made based on the above description. Not all embodiments are exhaustive. All obvious changes and modifications of the present invention are within the scope of the present invention.
Claims (4)
1. A power distribution network cable leakage current online detection method is characterized by comprising the following steps:
synchronously collecting the current at two ends of the cable to be detected to obtain current parameters including amplitude and phase at the same moment at the two ends of the cable to be detected;
calculating the leakage current amplitude according to the following formula:
in the formula, Δ I represents the leakage current amplitude, I1Representing the current amplitude, I, of one end of the cable to be tested2Representing the current amplitude, theta, at the other end of the cable to be tested1Indicating the phase of the current, theta, at one end of the cable to be tested2Representing the current phase at the other end of the cable under test.
2. The power distribution network cable leakage current online detection method according to claim 1, wherein the currents at two ends of the cable to be detected are collected in the following manner: the sampling current of the cable to be detected is obtained through the current transformer, the sampling current is converted into a voltage signal through the Hall current sensor and then is output to the analog-digital conversion circuit, and the voltage signal is converted into a digital signal by the analog-digital conversion circuit and then is output to the controller for calculation so as to obtain a current parameter.
3. The online detection method for the leakage current of the power distribution network cable according to claim 2, wherein the controller packages and uploads the current parameters together with the sampling time to the server, so that the server can judge whether the current parameters are the current parameters of the two ends of the cable to be detected at the same time through the sampling time.
4. A method for monitoring the insulation state of a power distribution network cable is characterized by comprising the following steps: the online detection method for the leakage current of the power distribution network cable according to claim 1 is adopted to calculate the leakage current amplitude of each phase of cable, and the insulation state of each phase of cable is correspondingly evaluated according to the variation trend of the leakage current amplitude of each phase of cable: with the increase of the amplitude of the leakage current, the insulation aging degree or the local damage degree of the cable is increased.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110159263.7A CN112946521A (en) | 2021-02-04 | 2021-02-04 | Power distribution network cable leakage current online detection method and insulation state monitoring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110159263.7A CN112946521A (en) | 2021-02-04 | 2021-02-04 | Power distribution network cable leakage current online detection method and insulation state monitoring method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112946521A true CN112946521A (en) | 2021-06-11 |
Family
ID=76242397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110159263.7A Pending CN112946521A (en) | 2021-02-04 | 2021-02-04 | Power distribution network cable leakage current online detection method and insulation state monitoring method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112946521A (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1043230A (en) * | 1988-11-24 | 1990-06-20 | 南京电力专科学校 | Vector difference type electric shock protector |
| CN102879716A (en) * | 2012-09-24 | 2013-01-16 | 哈尔滨理工大学 | Online monitoring method and device for main insulation of three-phase cable under metal sheath cross interconnection |
| CN103267931A (en) * | 2013-04-19 | 2013-08-28 | 国家电网公司 | Method for positioning intersecting interconnection cable intermediate head partial discharge |
| CN204256093U (en) * | 2014-12-04 | 2015-04-08 | 国家电网公司 | The On-line Fault monitoring device of cable splice in a kind of 10 ~ 35kV power distribution network |
| CN106207964A (en) * | 2016-08-04 | 2016-12-07 | 宋邦卓 | A kind of illuminating line protector based on leakage current vector transient detection |
| CN106443314A (en) * | 2016-11-29 | 2017-02-22 | 国网湖南省电力公司 | Electric consumption line missort detection method and device |
| CN108173570A (en) * | 2017-12-25 | 2018-06-15 | 安徽博达通信工程监理有限责任公司 | A kind of wiring architecture fault detect communication system |
| CN108919054A (en) * | 2018-07-05 | 2018-11-30 | 国网上海市电力公司 | The intelligent power distribution network short circuit fault localization method estimated based on load and branch line |
| CN109813978A (en) * | 2018-12-25 | 2019-05-28 | 武汉中原电子信息有限公司 | A kind of non-intruding load-type recognition methods of variation characteristic between comprehensive transient characteristic and stable state |
| CN109951128A (en) * | 2019-04-02 | 2019-06-28 | 合肥工业大学 | The SMPMSM drive system model-free current predictive control method and control system of inverter reference voltage vector on-line optimization |
| CN111157915A (en) * | 2019-12-31 | 2020-05-15 | 国网北京市电力公司 | Cable leakage current detection method and device, storage medium and processor |
| CN112014698A (en) * | 2020-08-26 | 2020-12-01 | 浙江巨磁智能技术有限公司 | Long cable residual current detection device and method for low-voltage alternating current power supply system |
-
2021
- 2021-02-04 CN CN202110159263.7A patent/CN112946521A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1043230A (en) * | 1988-11-24 | 1990-06-20 | 南京电力专科学校 | Vector difference type electric shock protector |
| CN102879716A (en) * | 2012-09-24 | 2013-01-16 | 哈尔滨理工大学 | Online monitoring method and device for main insulation of three-phase cable under metal sheath cross interconnection |
| CN103267931A (en) * | 2013-04-19 | 2013-08-28 | 国家电网公司 | Method for positioning intersecting interconnection cable intermediate head partial discharge |
| CN204256093U (en) * | 2014-12-04 | 2015-04-08 | 国家电网公司 | The On-line Fault monitoring device of cable splice in a kind of 10 ~ 35kV power distribution network |
| CN106207964A (en) * | 2016-08-04 | 2016-12-07 | 宋邦卓 | A kind of illuminating line protector based on leakage current vector transient detection |
| CN106443314A (en) * | 2016-11-29 | 2017-02-22 | 国网湖南省电力公司 | Electric consumption line missort detection method and device |
| CN108173570A (en) * | 2017-12-25 | 2018-06-15 | 安徽博达通信工程监理有限责任公司 | A kind of wiring architecture fault detect communication system |
| CN108919054A (en) * | 2018-07-05 | 2018-11-30 | 国网上海市电力公司 | The intelligent power distribution network short circuit fault localization method estimated based on load and branch line |
| CN109813978A (en) * | 2018-12-25 | 2019-05-28 | 武汉中原电子信息有限公司 | A kind of non-intruding load-type recognition methods of variation characteristic between comprehensive transient characteristic and stable state |
| CN109951128A (en) * | 2019-04-02 | 2019-06-28 | 合肥工业大学 | The SMPMSM drive system model-free current predictive control method and control system of inverter reference voltage vector on-line optimization |
| CN111157915A (en) * | 2019-12-31 | 2020-05-15 | 国网北京市电力公司 | Cable leakage current detection method and device, storage medium and processor |
| CN112014698A (en) * | 2020-08-26 | 2020-12-01 | 浙江巨磁智能技术有限公司 | Long cable residual current detection device and method for low-voltage alternating current power supply system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102998545B (en) | Online transformer winding work state monitoring method | |
| CN101459334B (en) | Electrical power system failure information obtaining method | |
| CN110082636B (en) | Power cable fault positioning method and system | |
| CN102680798B (en) | Online measurement method and device for grounding resistor of rod tower | |
| CN110687408B (en) | Cable insulation monitoring method and device | |
| CN101576593B (en) | Array type inferior insulator local electric field detector and inverse diagnosis method | |
| CN109813987B (en) | Transformer direct-current magnetic bias state evaluation method based on BP neural network | |
| CN201773140U (en) | Alternating current and direct current hybrid electric field intensity measuring device | |
| CN107290629B (en) | 10KV low-voltage distribution network ground fault positioning method | |
| CN107621591A (en) | A kind of transmission line of electricity iteration distance-finding method based on zero mould traveling wave speed variation characteristic | |
| CN202141752U (en) | Online monitoring device for metal zinc oxide lightning arrester | |
| CN201576052U (en) | Insulation testing device with humidity compensation function | |
| CN109521391A (en) | The detection device and method of generator voltage mutual inductor winding interturn short-circuit failure | |
| CN110244192B (en) | Electric power overhead line ground fault distance measurement method | |
| CN106771843B (en) | Fault traveling wave distance measurement method for single-core power cable | |
| CN102645616A (en) | Fault addressing method for transmission line | |
| CN110716111B (en) | Ultrahigh voltage XLPE cable insulation on-line monitoring device and monitoring method based on vector method | |
| CN102346230B (en) | Method and device for online detection of transformer sleeve | |
| CN112946521A (en) | Power distribution network cable leakage current online detection method and insulation state monitoring method | |
| CN111564844A (en) | CVT secondary side harmonic monitoring abnormal data correction method | |
| CN111289837A (en) | Method and system for evaluating latent fault of power distribution network equipment | |
| CN113376548B (en) | Cable state monitoring method and device based on cable aging characteristic extraction | |
| CN113092939B (en) | Power distribution network fault positioning method based on PMU and smart electric meter | |
| CN205562725U (en) | Trouble fixed point appearance of distribution network | |
| CN102221682A (en) | Apparatus of rapidly detecting three-phase high-error electric energy meter and measuring method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |