CN111965498A - Automatic inspection and fault positioning device for insulation state of hydraulic generator screw - Google Patents
Automatic inspection and fault positioning device for insulation state of hydraulic generator screw Download PDFInfo
- Publication number
- CN111965498A CN111965498A CN202010710541.9A CN202010710541A CN111965498A CN 111965498 A CN111965498 A CN 111965498A CN 202010710541 A CN202010710541 A CN 202010710541A CN 111965498 A CN111965498 A CN 111965498A
- Authority
- CN
- China
- Prior art keywords
- module
- screw
- insulation
- fault
- control module
- 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.)
- Granted
Links
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
- G01R31/12—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
-
- 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
- G01R31/34—Testing dynamo-electric machines
-
- 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
- H02H7/06—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 dynamo-electric generators; for synchronous capacitors
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention relates to the technical field of generators and discloses a hydraulic generator screw insulation state automatic inspection and fault positioning device which has two working modes of online monitoring and offline detection. The device comprises a screw rod, wherein a lead is connected to the screw rod, the screw rod is connected with an electrical control module through the lead, the electrical control module carries out online monitoring or offline detection on the screw rod and transmits a monitoring or detection signal to an upper computer analysis system; the electrical control module contains: the voltage conversion function module, the data acquisition and ADC conversion module, the logic control module and the data communication module have a multi-level safety protection function; the upper computer monitoring and control system comprises a fault diagnosis module, an insulation health state evaluation module, a characteristic information display module, a control signal sending module and a fault case library module. Compared with the automatic inspection and fault positioning device in the prior art, the device provided by the invention has the characteristics of strong safety, high accuracy and good economic performance.
Description
Technical Field
The invention relates to the technical field of generators, in particular to a device for automatically inspecting the insulation state of a hydraulic generator screw and positioning a fault.
Background
In the present stage, insulation monitoring of the penetrating screw rod is mainly realized through manual regular inspection, and hidden danger of insulation reduction of the stator penetrating screw rod is eliminated. On one hand, the method has no pertinence and low working efficiency; on the other hand, online monitoring cannot be realized, the insulation state of the screw rod of the stator core-through path cannot be mastered in real time, and early warning can be timely carried out before a fault occurs. There is no mature and reliable online monitoring method, and the existing technical solutions include the following two types:
1. based on the injection type unbalanced bridge principle, the insulation performance of the stator feed-through screw is monitored on line, and a fault screw is positioned. The basic principle of the method is that all the penetrating screws are connected end to end, voltage is applied to two ends, and when insulation reduction or ground fault occurs in screw insulation, relevant characteristics can be extracted from loop current, and fault signals can be identified. The positive electrode and the negative electrode of the voltage are grounded in an exchange mode, and the position of the fault screw can be obtained through the unbalanced bridge. (invention patent (in right): CN 201010106363-generator stator core tightening screw insulation on-line monitoring and grounding protection method). The study of patent documents and papers on the first pass of the patent documents shows that the scheme does not consider the influence of self induced electromotive force of the screw, and has the hidden trouble of bringing about secondary failure.
2. The screw rod is connected with a current limiting resistor and a sampling resistor in series, the voltage of the sampling resistor is monitored, and the screw rod insulation reduction or ground fault is warned in advance. The method is proposed by researchers of North China university of electric power. The scheme has the problems of multiple lead wires and monitoring signals, the lead wires from the middle part of the screw rod are required to be arranged in the stator iron core, the lead wires are more complicated, and the signals are interfered by a strong magnetic environment.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the problems, the automatic inspection and fault positioning device for the insulation state of the penetrating screw of the stator of the hydraulic generator, which has strong safety, high accuracy and good economical efficiency, is developed.
The technical scheme adopted by the invention is as follows: the automatic inspection and fault positioning device for the insulation state of the screw of the hydraulic generator comprises a screw, wherein a lead is connected to the screw, the screw is connected with an electrical control module through the lead, and the electrical control module carries out online monitoring on the screw and transmits a monitoring signal to an upper computer analysis system;
the electrical control module includes: the device comprises a voltage conversion function module, a data acquisition and ADC conversion module, a logic control module and a data communication module;
the voltage conversion function module is used for converting an external power supply of the electric control module into a direct current power supply;
the data acquisition and ADC conversion module is used for acquiring and monitoring or detecting a line electric signal and performing necessary AD conversion;
the logic control module is used for sequentially connecting and disconnecting the outgoing line of the screw with a current power supply output after being processed by the voltage transmission device in a certain period so as to realize a polling monitoring or detection function;
and the communication functional module is used for transmitting the line signals (current or voltage) which are monitored in real time and stored to the upper computer analysis system in a wired or wireless mode.
Furthermore, the device also comprises a generator stator core, and the generator stator core is led out to the grounding end of the electric control module through a lead.
Furthermore, the electric control module also comprises a filtering function module and a locking protection module; the filtering function module is used for blocking high-frequency signals above 10Hz in the line of the positioning device, eliminating potential safety hazards caused by the fact that the screw rod induces alternating current electromotive force to be externally led, meanwhile, only voltage or current signals below 10Hz exist in the detection line, and the insulation health degree of the screw rod can be conveniently and accurately reflected.
Further, the locking protection module realizes the following functions:
if only one screw rod branch in the circuit is in a connection state, no matter what output operation is carried out by the program, the logic circuit does not respond to any operation except the disconnection of all the branches;
if two or more screw rod branches are conducted simultaneously in the circuit, the logic circuit will disconnect all the channels and send out alarm signal.
Furthermore, a fast melting protective tube and a current-limiting protection resistor are sequentially connected in series on the lead.
Each screw rod branch circuit and the detection main circuit are provided with a current limiting resistor, so that the current limiting of the conduction branch circuit is ensured to be within 0.1A under the condition that the insulation of the screw rods is deteriorated, damaged or the blocking protection fails at an extremely low probability, and the two screw rods are conducted simultaneously.
Further, the fusing current of the fast fusing fuse is set to 0.1A.
Each screw rod branch lead is connected with the electric control module after being connected with the fast melting fuse tube in series, the fusing current of the fast melting fuse tube is set to be 0.1A, the safety measures are guaranteed to be invalid under extremely low probability, and the fast melting fuse tube is fused and protected when the branch current is larger than 0.1A.
Furthermore, the upper computer analysis system comprises a fault diagnosis module, an insulation health state evaluation module, a characteristic information display module, a control signal sending module and a fault case library module.
The insulation health state evaluation module is used for processing data uploaded by the electric control module and judging the insulation health state of the screw rod according to the data;
the fault diagnosis module is used for quickly positioning a fault place and giving a fault reason when the screw insulation fails.
The characteristic information display module is used for displaying insulation resistance values of the screws with reduced insulation or grounding, screw numbers and other related information, has data storage and review functions, can check the insulation resistance values of the screws in a certain period, and observes the variation trend of the insulation resistance of the screws;
the control signal sending module sends a control signal to the electrical control module and is used for controlling and switching the working mode (online monitoring or offline detection) of the electrical control module;
and when the fault case library module gives an alarm, the state information of the screw branch is automatically added, so that the fault case library is perfected.
Compared with the prior art, the beneficial effects of adopting the technical scheme are as follows: compared with the automatic inspection and fault positioning device in the prior art, the device provided by the invention has the characteristics of strong safety, high accuracy and good economic performance.
Drawings
FIG. 1 is a schematic diagram of the logic of the electrical control module of the device of the present invention.
Detailed Description
The invention is further described below.
The invention provides a hydraulic generator screw insulation state automatic inspection and fault positioning device, which comprises the following components:
the screw numbering device comprises a plurality of screws, wherein all the screws are numbered from 1 to n, one end of each screw is connected with a lead, and the leads are also numbered corresponding to the screws.
Each lead is connected in series with a fast melting protective tube and a current-limiting protection resistor so as to limit the grounding current of the screw rod in a safety range when one-point insulation is damaged and grounded and protect relevant parts of the generator from being damaged.
The lead is connected with the fast melting fuse tube and the current-limiting protection resistor in series and then is connected to the electric control module. The electric control module monitors or detects the screw rod and transmits the acquired signal to an upper computer analysis system.
The electrical control module comprises the following components:
the built-in voltage conversion functional module: the power supply device is used for converting an external power supply of the electric control module into a direct current power supply;
the device comprises a data acquisition and ADC conversion module: the device is used for collecting and monitoring or detecting line electric signals and carrying out necessary AD conversion;
the embedded logic control module: the device is used for sequentially connecting and disconnecting the outgoing line of the screw with a current power supply output after being processed by the voltage transmission device in a certain period so as to realize a polling monitoring or detection function; in this embodiment, a polling on-off relay set is used;
the embedded communication function module: the system is used for transmitting the line signals (current or voltage) monitored and stored in real time to an upper computer analysis system in a wired or wireless mode.
Meanwhile, the electrical control module has a multi-level safety protection function so as to eliminate the negative effects caused by the external lead of the screw rod and prevent the monitoring device from generating potential safety hazards on the original structure.
And (3) a filtering function: the low-pass filter is arranged in the line to block high-frequency signals above 10Hz in the line, so that potential safety hazards caused by the fact that the screw induces alternating-current electromotive force to be led out are eliminated, and meanwhile, only voltage or current signals below 10Hz exist in the detection line, so that the insulation health degree of the screw can be accurately reflected.
Locking protection function: the following functions are realized by means of hardware and logic control in the prior art: if one of the screw legs is still on, the logic circuit does not respond to any operation other than turning off all of the legs, regardless of the output operation performed by the program. Once two or more screw rod branches are simultaneously conducted, all the passages are immediately cut off, and an alarm signal is sent out.
Distributed, multi-step current limiting protection: each screw rod branch circuit and the detection main circuit are provided with a current limiting resistor, so that the current limiting of the conduction branch circuit is ensured to be within 0.1A under the condition that the insulation of the screw rods is deteriorated, damaged or the blocking protection fails at an extremely low probability, and the two screw rods are conducted simultaneously.
Protection of a fast-melting fuse: each screw rod branch outgoing line is connected with the electric control module after being connected with the fast melting fuse tube in series, the fusing current of the fast melting fuse tube is set to be 0.1A, the safety measures are guaranteed to be invalid under extremely low probability, and the fast melting fuse tube is fused and protected when the branch current is larger than 0.1A.
The upper computer analysis system mainly comprises the following functional modules:
and the insulation health state evaluation module can process the data uploaded by the electric control module and judge the insulation states of the screw rod such as insulation health, abnormity, overrun and the like according to the data.
And the fault diagnosis module is used for quickly positioning a fault place and giving out a fault reason when the screw insulation fails.
The characteristic information display module is used for displaying insulation resistance values of the screws with reduced insulation or grounding, screw numbers and other related information, has data storage and review functions, can check the insulation resistance values of the screws in a certain period, and observes the variation trend of the insulation resistance of the screws;
the control signal sending module can send a control signal to enable the working mode of the electrical control module to be switched between two working modes of on-line monitoring of screw insulation and positioning and manual calibration of screw insulation (off-line detection).
And the fault case library module can automatically add information during state alarm, and perfect a fault case library for auxiliary diagnosis reference.
Preferably, when the number of the screws is small, the screws are connected to one electric control module in a lead-in mode, and when the number of the screws is large, the leads are divided into a plurality of groups and are respectively led to the plurality of electric control modules, so that one group of screws is guaranteed to correspond to one electric control module.
Preferably, in this embodiment, the logic control module employs a polling on-off relay set.
Preferably, in this embodiment, the line signal sensor of the data acquisition and ADC conversion module adopts high-precision CT.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed. Those skilled in the art to which the invention pertains will appreciate that insubstantial changes or modifications can be made without departing from the spirit of the invention as defined by the appended claims.
Claims (7)
1. The automatic inspection and fault positioning device for the insulation state of the screw of the hydraulic generator is characterized by comprising a screw, wherein a lead is connected to the screw, the screw is connected with an electrical control module through the lead, and the electrical control module is used for collecting signals of the screw and transmitting the collected signals to an upper computer analysis system;
the electrical control module includes: the device comprises a voltage conversion function module, a data acquisition and ADC conversion module, a logic control module and a data communication module;
the voltage conversion function module is used for converting an external power supply of the electric control module into a direct current power supply;
the data acquisition and ADC conversion module is used for acquiring and monitoring or detecting a line electric signal and performing necessary AD conversion;
the logic control module is used for sequentially connecting and disconnecting the outgoing line of the screw with the current power supply output after being processed by the voltage conversion function module in a certain period so as to realize a polling monitoring or detection function;
and the communication function module is used for transmitting the line signals which are monitored and stored in real time to an upper computer analysis system.
2. The automatic inspection and fault location device for the insulation state of the hydraulic generator screw according to claim 1, further comprising a generator stator core, wherein the generator stator core is led out to a grounding end of the electrical control module through a lead.
3. The automatic inspection and fault location device for the insulation state of the screw of the hydraulic generator according to claim 1, wherein the electrical control module further comprises a filtering function module and a locking protection module; the filtering function module is used for blocking high-frequency signals above 10Hz in the line of the positioning device.
4. The automatic inspection and fault location device for the insulation state of the screw of the hydraulic generator according to claim 3, wherein the locking protection module is used for realizing the following functions:
if only one screw rod branch in the circuit is in a connection state, no matter what output operation is carried out by the program, the logic circuit does not respond to any operation except the disconnection of all the branches;
if two or more screw rod branches are conducted simultaneously in the circuit, the logic circuit will disconnect all the channels and send out alarm signal.
5. The automatic inspection and fault location device for the insulation state of the screw of the hydraulic generator according to claim 1, wherein a fast melting protective tube and a current limiting protection resistor are sequentially connected in series on the lead.
6. The automatic inspection and fault location device for the insulation state of the screw of the hydraulic generator according to claim 5, wherein the fusing current of the fast fusing fuse tube is set to be 0.1A.
7. The automatic inspection and fault positioning device for the insulation state of the screw of the hydraulic generator according to claim 1, wherein the upper computer analysis system comprises an insulation health state evaluation module, a fault diagnosis module, a characteristic information display module, a control signal sending module and a fault case library module;
the insulation health state evaluation module is used for processing data uploaded by the electric control module and judging the insulation health state of the screw rod according to the data;
the fault diagnosis module is used for quickly positioning a fault place and giving a fault reason when the screw insulation fails;
the characteristic information display module is used for displaying the insulation resistance value and the screw number of the screw with reduced insulation or grounding and has the functions of data storage and review;
the control signal sending module sends a control signal to the electrical control module and is used for controlling and switching the working mode of the electrical control module;
and when the fault case library module gives an alarm, the state information of the screw branch is automatically added, so that the fault case library is perfected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010710541.9A CN111965498B (en) | 2020-07-22 | 2020-07-22 | Automatic inspection and fault positioning device for insulation state of hydraulic generator screw |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010710541.9A CN111965498B (en) | 2020-07-22 | 2020-07-22 | Automatic inspection and fault positioning device for insulation state of hydraulic generator screw |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111965498A true CN111965498A (en) | 2020-11-20 |
| CN111965498B CN111965498B (en) | 2023-01-24 |
Family
ID=73364246
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010710541.9A Active CN111965498B (en) | 2020-07-22 | 2020-07-22 | Automatic inspection and fault positioning device for insulation state of hydraulic generator screw |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111965498B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114705985A (en) * | 2022-03-31 | 2022-07-05 | 东方电气集团东方电机有限公司 | Stator core compression state monitoring device, method and equipment |
| CN114740266A (en) * | 2022-04-08 | 2022-07-12 | 东方电气集团东方电机有限公司 | Insulation monitoring method, insulation monitoring device, electronic equipment and storage medium |
| CN114779073A (en) * | 2022-03-31 | 2022-07-22 | 东方电气集团东方电机有限公司 | Stator core compression state fault detection device, detection method, generator set monitoring system and computer readable storage medium |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101799518A (en) * | 2010-02-05 | 2010-08-11 | 贵阳新光电气有限公司 | Online monitoring and grounding protection methods of insulation of generator stator core tightening screw rods |
| EP2884290A1 (en) * | 2013-12-13 | 2015-06-17 | Bender GmbH & Co. KG | Device and method for insulation monitoring in a power supply system having high ohmic grounded star point |
| CN104977513A (en) * | 2015-06-30 | 2015-10-14 | 国家电网公司 | High-voltage cable outer sheath insulation state on-line monitoring system and control method thereof |
| CN106443442A (en) * | 2016-09-06 | 2017-02-22 | 滕方剑 | Automatic insulation detection, automatic baking and automatic grounding integrated device for high-voltage motor |
| CN108872802A (en) * | 2017-05-12 | 2018-11-23 | 中国石油化工股份有限公司 | A kind of cable local discharge distributed monitoring system |
| CN109738829A (en) * | 2018-12-18 | 2019-05-10 | 江苏金坛绿能新能源科技有限公司 | A kind of battery pack Insulation Inspection System and detection method |
| CN111381136A (en) * | 2020-05-15 | 2020-07-07 | 山东威纳电气有限公司 | Device for detecting insulation of high-voltage motor on line |
-
2020
- 2020-07-22 CN CN202010710541.9A patent/CN111965498B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101799518A (en) * | 2010-02-05 | 2010-08-11 | 贵阳新光电气有限公司 | Online monitoring and grounding protection methods of insulation of generator stator core tightening screw rods |
| EP2884290A1 (en) * | 2013-12-13 | 2015-06-17 | Bender GmbH & Co. KG | Device and method for insulation monitoring in a power supply system having high ohmic grounded star point |
| CN104977513A (en) * | 2015-06-30 | 2015-10-14 | 国家电网公司 | High-voltage cable outer sheath insulation state on-line monitoring system and control method thereof |
| CN106443442A (en) * | 2016-09-06 | 2017-02-22 | 滕方剑 | Automatic insulation detection, automatic baking and automatic grounding integrated device for high-voltage motor |
| CN108872802A (en) * | 2017-05-12 | 2018-11-23 | 中国石油化工股份有限公司 | A kind of cable local discharge distributed monitoring system |
| CN109738829A (en) * | 2018-12-18 | 2019-05-10 | 江苏金坛绿能新能源科技有限公司 | A kind of battery pack Insulation Inspection System and detection method |
| CN111381136A (en) * | 2020-05-15 | 2020-07-07 | 山东威纳电气有限公司 | Device for detecting insulation of high-voltage motor on line |
Non-Patent Citations (1)
| Title |
|---|
| 高洪喜等: "发电机转子绝缘在线监测装置在水电站中的应用", 《工程建设与设计》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114705985A (en) * | 2022-03-31 | 2022-07-05 | 东方电气集团东方电机有限公司 | Stator core compression state monitoring device, method and equipment |
| CN114779073A (en) * | 2022-03-31 | 2022-07-22 | 东方电气集团东方电机有限公司 | Stator core compression state fault detection device, detection method, generator set monitoring system and computer readable storage medium |
| WO2023185429A1 (en) * | 2022-03-31 | 2023-10-05 | 东方电气集团东方电机有限公司 | Stator core pressing state fault detection method and apparatus, generator set monitoring system and computer-readable storage medium |
| CN114779073B (en) * | 2022-03-31 | 2023-10-13 | 东方电气集团东方电机有限公司 | Stator core compression state fault detection device, detection method, generator set monitoring system and computer readable storage medium |
| CN114705985B (en) * | 2022-03-31 | 2023-10-13 | 东方电气集团东方电机有限公司 | Stator core compression state monitoring device, monitoring method and monitoring equipment |
| CN114740266A (en) * | 2022-04-08 | 2022-07-12 | 东方电气集团东方电机有限公司 | Insulation monitoring method, insulation monitoring device, electronic equipment and storage medium |
| WO2023193529A1 (en) * | 2022-04-08 | 2023-10-12 | 东方电气集团东方电机有限公司 | Insulation monitoring method and apparatus, electronic device and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111965498B (en) | 2023-01-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111965498B (en) | Automatic inspection and fault positioning device for insulation state of hydraulic generator screw | |
| US10794945B2 (en) | Method for detecting and locating single-phase ground fault on low current grounded power-distribution network | |
| US10222409B2 (en) | Method and system for detecting and locating single-phase ground fault on low current grounded power-distribution network | |
| CN116520093B (en) | High-voltage bus operation fault positioning method and device | |
| CN113030715B (en) | Residual current operated circuit breaker performance detection device and fault judgment method | |
| CN111157841A (en) | Fault quick positioning device for secondary circuit of electric operation type isolating switch | |
| CN105891679A (en) | Fault detection system and method for electric power grid | |
| CN105445594A (en) | Power grid fault detection system | |
| CN201181321Y (en) | Earthing detection circuit of locomotive control circuit | |
| CN107340468A (en) | A kind of high voltage isolator detecting system | |
| CN219204173U (en) | Direct-current grounding auxiliary power supply device capable of achieving road pulling and searching | |
| CN202281817U (en) | Microcomputer low current grounding and line-selecting system | |
| CN209561923U (en) | Intelligent railway weak electric system power lightning protection distribution device | |
| CN106908653A (en) | OPGW on-line monitoring systems and method | |
| CN114441990B (en) | Electric leakage detection device and method for traffic signal machine | |
| CN211783595U (en) | Real-time monitoring system for transformer | |
| CN212781158U (en) | Low-current single-phase earth fault on-line monitoring device | |
| CN112881946B (en) | Double-core current transformer disconnection detection method and device and circuit breaker | |
| CN107607834A (en) | Transformer station's OPGW composite cable on-line monitoring system and method | |
| CN111398857A (en) | Single-phase earth fault detection system of line selection device for arc suppression coil grounding system | |
| CN111624511A (en) | Grounding current online monitoring device and online monitoring control method for transformer iron core | |
| CN111342552A (en) | Early warning system for electric power operation maintenance and preventive test of 0.4KV power distribution system | |
| CN217112562U (en) | Power supply and distribution fault handling device and power supply and distribution system | |
| CN212111744U (en) | Single-phase earth fault detection system of line selection device for arc suppression coil grounding system | |
| CN215728736U (en) | Loop checking device and system |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |