CN109375134B - Generator outlet voltage transformer internal fault on-line monitoring method and system - Google Patents
Generator outlet voltage transformer internal fault on-line monitoring method and system Download PDFInfo
- Publication number
- CN109375134B CN109375134B CN201811165640.2A CN201811165640A CN109375134B CN 109375134 B CN109375134 B CN 109375134B CN 201811165640 A CN201811165640 A CN 201811165640A CN 109375134 B CN109375134 B CN 109375134B
- Authority
- CN
- China
- Prior art keywords
- phase
- voltage transformers
- group
- voltage
- generator
- 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.)
- Expired - Fee Related
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
Abstract
The invention relates to a method and a system for online monitoring internal faults of a voltage transformer at an outlet of a generator, wherein the method comprises the following steps: collecting the nanoampere exciting currents of three groups of voltage transformers at the outlet of the generator; each group of voltage transformers consists of three voltage transformers which are respectively connected with three-phase voltage of the generator; calculating the amplitude and the phase of the exciting current of each group of voltage transformers based on the acquired exciting current, and obtaining a vector diagram of the amplitude and the phase; and carrying out fault judgment according to the vector sum development and change trend and the mutation quantity condition of the vector diagram, judging that the group of voltage transformers are normal if the vector sum of the vector diagram is zero, and judging that the turn-to-turn short circuit occurs in the group of voltage transformers if the vector sum of the vector diagram is not zero. According to the invention, the characteristic quantity representing the fault development is effectively captured in the latent period of the fault of the mutual inductor, and the alarm signal is given in time according to the development change trend of the fault characteristic quantity, so that the occurrence of serious accidents can be avoided, and the reliability of equipment is improved.
Description
Technical Field
The invention belongs to the technical field of voltage transformer fault monitoring, and particularly relates to a method and a system for online monitoring of internal faults of a voltage transformer at an outlet of a generator.
Background
The existing fault monitoring scheme of the voltage transformer (PT) can only judge whether a fault exists or search the existing fault generally, the monitoring analysis of the turn-to-turn short circuit latency of the voltage transformer is not concerned, and the fault of the voltage transformer cannot be predicted, so that the emergency processing time is greatly shortened, and the reliability of detection equipment is reduced.
Disclosure of Invention
The invention aims to provide a method and a system for monitoring internal faults of a voltage transformer at an outlet of a generator on line, which can effectively capture characteristic quantities representing fault development in the latent period of the fault of the transformer, and can give an alarm signal in time according to the development change trend of the fault characteristic quantities so as to avoid serious accidents.
The invention provides an internal fault on-line monitoring method for a voltage transformer at an outlet of a generator, which comprises the following steps:
collecting the nanoampere exciting currents of three groups of voltage transformers at the outlet of the generator; each group of voltage transformers consists of three voltage transformers which are respectively connected with three-phase voltage of the generator;
calculating the amplitude and the phase of the exciting current of each group of voltage transformers based on the acquired exciting current, and obtaining a vector diagram of the amplitude and the phase;
and carrying out fault judgment according to the vector sum development and change trend and the mutation quantity condition of the vector diagram, judging that the group of voltage transformers are normal if the vector sum of the vector diagram is zero, and judging that the turn-to-turn short circuit occurs in the group of voltage transformers if the vector sum of the vector diagram is not zero.
Further, the method further comprises:
and synchronously sampling the exciting current of the same-phase voltage transformers in the three groups of voltage transformers, and performing fault judgment by combining the exciting current data of the same-phase voltage transformers.
Further, the method further comprises:
and alarming and prompting the condition of turn-to-turn short circuit.
The invention also provides an internal fault on-line monitoring system of the generator outlet voltage transformer, which comprises a high-precision micro-current sensor, a data acquisition unit and a monitoring host, wherein the high-precision micro-current sensor is sleeved on the grounding wires of the three groups of voltage transformers at the outlet of the generator in a core-through mode and is used for measuring the exciting currents of the three groups of voltage transformers at the outlet of the generator and transmitting the measured exciting current data to the data acquisition unit for processing; each group of voltage transformers consists of three voltage transformers which are respectively connected with three-phase voltage of the generator;
the monitoring host is connected with the data acquisition unit and used for calculating the amplitude and the phase of the exciting current of each group of voltage transformers based on the exciting current data processed by the data acquisition unit, obtaining a vector diagram of the voltage transformers, carrying out fault judgment according to the vector sum of the vector diagram, the development change trend and the mutation quantity condition, judging that the group of voltage transformers are normal if the vector sum of the vector diagram is zero, and judging that the group of voltage transformers have turn-to-turn short circuit if the vector sum of the vector diagram is not zero.
Furthermore, the monitoring host is also used for carrying out fault judgment by combining synchronous sampling data of exciting currents of in-phase voltage transformers in the three groups of voltage transformers.
Furthermore, the monitoring host is also used for carrying out alarm prompt on the condition that turn-to-turn short circuit is judged to occur.
By means of the scheme, the internal fault on-line monitoring method and the internal fault on-line monitoring system for the voltage transformer at the outlet of the generator effectively capture the characteristic quantity representing fault development in the latent period of the fault of the transformer, give an alarm signal in time according to the development change trend of the fault characteristic quantity, avoid serious accidents and improve the reliability of equipment. According to the scheme, the connection and wiring structure of the existing voltage transformer is not required to be changed, the installation mode is simple and reliable, and potential safety hazards are avoided.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of a generator outlet voltage transformer configuration;
FIG. 2 is a schematic diagram of the principle of fault judgment of the motor outlet voltage transformer according to the present invention; wherein, the diagram (a) is a normal time schematic diagram, the diagram (b) is a one-phase fault schematic diagram, and the diagram (c) is a two-phase fault schematic diagram;
FIG. 3 is a schematic structural diagram of an internal fault online monitoring system of a generator outlet voltage transformer according to the present invention.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
The embodiment provides an internal fault online monitoring method for a generator outlet voltage transformer, which comprises the following steps:
collecting the nanometer exciting currents of three groups of voltage transformers at the outlet of the generator; each group of voltage transformers consists of three voltage transformers which are respectively connected with three-phase voltage of the generator;
calculating the amplitude and the phase of the exciting current of each group of voltage transformers based on the acquired exciting current, and obtaining a vector diagram of the amplitude and the phase;
and carrying out fault judgment according to the vector sum development and change trend and the mutation quantity condition of the vector diagram, judging that the group of voltage transformers are normal if the vector sum of the vector diagram is zero, and judging that the turn-to-turn short circuit occurs in the group of voltage transformers if the vector sum of the vector diagram is not zero.
By the online monitoring method and the online monitoring system for the internal fault of the voltage transformer at the outlet of the generator, the characteristic quantity (vector sum of the excitation current vector diagram) representing the fault development is effectively captured in the latent period of the fault of the transformer, and an alarm signal is given in time according to the development change trend of the fault characteristic quantity, so that the occurrence of serious accidents can be avoided, and the reliability of equipment is improved. According to the scheme, the connection and wiring structure of the existing voltage transformer is not required to be changed, the installation mode is simple and reliable, and potential safety hazards are avoided.
In this embodiment, the method further includes: and synchronously sampling the exciting current of the same-phase voltage transformers in the three groups of voltage transformers, and performing fault judgment by combining the exciting current data of the same-phase voltage transformers.
In this embodiment, the method further includes:
and alarming and prompting the condition of turn-to-turn short circuit. Various alarm modes can be adopted, such as sound alarm, short message alarm and the like.
Referring to fig. 3, the embodiment further provides an internal fault online monitoring system of a generator outlet voltage transformer, which includes a high-precision micro-current sensor, a data acquisition unit and a monitoring host, wherein the data acquisition unit and the monitoring host adopt an RS485 communication mode; adopt 4 core cable junction, 2 cores are used for the power supply, and 2 cores are used for RS485 communication in addition. The high-precision micro-current sensor is sleeved on grounding wires of three groups of voltage transformers at the outlet of the generator in a core-through mode and is used for measuring the exciting currents of the three groups of voltage transformers at the outlet of the generator and transmitting the measured exciting current data to the data acquisition unit for processing; each group of voltage transformers consists of three voltage transformers which are respectively connected with three-phase voltage of the generator;
the monitoring host is connected with the data acquisition unit and used for calculating the amplitude and the phase of the exciting current of each group of voltage transformers based on the exciting current data processed by the data acquisition unit, obtaining a vector diagram of the voltage transformers, carrying out fault judgment according to the vector sum of the vector diagram, the development change trend and the mutation quantity condition, judging that the group of voltage transformers are normal if the vector sum of the vector diagram is zero, and judging that the group of voltage transformers have turn-to-turn short circuit if the vector sum of the vector diagram is not zero.
This generator outlet voltage transformer internal fault on-line monitoring system adopts the little current sensor of high accuracy, is special to the measurement of nanoampere level electric current to have very high phase accuracy, cooperate high accuracy data acquisition unit, can accurate measurement 10 microampere's current signal, and phase place measurement accuracy can accomplish within three minutes. In the process of gradual development of the faults of the voltage transformer, the vector sum of the exciting currents can have obvious reaction, and the fault condition of the voltage transformer can be effectively judged by taking the vector sum as a characteristic quantity. The monitoring host can display data information of all the monitored voltage transformers, including information such as a trend graph of characteristic quantity, mutation quantity, transverse comparison of in-phase voltage transformer data and the like.
Through the online monitoring system for the internal fault of the voltage transformer at the outlet of the generator, the characteristic quantity (vector sum of the excitation current vector diagram) representing the fault development is effectively captured in the latent period of the fault of the transformer, and an alarm signal is given in time according to the development change trend of the fault characteristic quantity, so that the occurrence of serious accidents can be avoided, and the reliability of equipment is improved. The online monitoring system does not need to change the connection and wiring structure of the existing voltage transformer, and the installation mode is simple and reliable and has no potential safety hazard.
In this embodiment, the monitoring host is further configured to perform fault determination by combining synchronous sampling data of exciting currents of in-phase voltage transformers in the three groups of voltage transformers, so that influences of external factors such as power supply voltage fluctuation on fault determination can be eliminated.
In this embodiment, the monitoring host is further configured to perform an alarm prompt on the condition that it is determined that the turn-to-turn short circuit occurs. Various alarm modes can be adopted, such as sound alarm, short message alarm and the like.
The present invention is described in further detail below.
The outlet of the generator set is usually designed with 3 groups of PT (1YH, 2YH and 3YH), wherein the secondary circuit of 1 group adopts a B-phase grounding mode and is used for providing 3-phase voltage for an automatic excitation regulator (AVR, the first one), a fault recording system and a DCS system, and in addition, 1 group of opening triangles are led out to provide zero-sequence voltage. The secondary side neutral points of other 2 groups of PT are grounded, and voltage signals are provided for devices such as protection (2 groups), metering, AVR (two groups of PT) and the like. The PT configuration is schematically shown in FIG. 1.
Measuring and monitoring leakage currents (exciting currents) of three groups of PTs (three in each phase and nine in total) at the outlet of the generator, and calculating the amplitude and the phase of the leakage currents to obtain a vector diagram of the leakage currents. If the vector sum of the vector diagram is zero and zero, judging that the three groups of PTs are normal; and if the vector sum is not zero, judging that the three groups of PT have turn-to-turn short circuit. Considering that the probability of simultaneous failures of multiple PTs is extremely low, once a PT fails, there is a clear reflection from the trend, the mutation amount and the lateral contrast graph.
The specific criteria of the three groups of PT turn-to-turn short circuits at the outlet of the generator are as follows:
when three PTs in a group are normal, the excitation currents of the three-phase PTs should be substantially symmetrical, and the vectors thereof should be substantially zero, as shown in fig. 2 (a); when one of the PT groups fails, the vector sum will change, and the increment of the vector sum and the increment of the failed phase current should be substantially identical, as shown in fig. 2 (b); when two of PT groups fail at the same time, the vector sum should change less than the added value of the failed phase current in consideration of the phase relationship, but the phase of the vector sum will change significantly as shown in fig. 2 (c).
The measurement of the excitation current is performed using a high-precision micro-current sensor (dedicated to milli-level current measurement) whose mounting position is shown in fig. 3. Can be sleeved on the grounding wire of the PT in a core-through mode. If the PT can not be installed at each PT, the PT can be sleeved on the neutral point grounding wire of the 1 group of PTs. In this way, the zero sequence current of the PT excitation winding can be measured, and the fault information of the PT can be obtained according to the amplitude variation trend of the current and the data comparison among 3 groups of PT.
In this embodiment, a synchronous sampling mode is adopted for measuring 9 pieces of PT exciting current. The influence of external factors such as power supply voltage fluctuation on fault judgment can be easily eliminated.
Referring to the PT configuration diagram shown in fig. 1, the process of online monitoring of internal faults of the generator outlet voltage transformer includes:
1) excitation currents of 9 PT were measured, three phases A/B/C, 3 per phase. AD is AD7626 with a 16 bit 10MHz sampling rate.
2) With 3 AD channels, 3 of the same phase only need to be measured synchronously. After one phase measurement is completed, the analog switch is used to switch to another phase.
3) 3 PTs on the same phase were measured each time; for example, first measure 3 on phase A; after 10s, 3 on B were measured; after a further 10s, 3 of the C phases were measured. After 9 measurements were completed, 30 more seconds passed and a cycle was restarted. Time interval: 10s, 30s are approximate times. The inter-phase switching is fast; the cycle interval is set by the upper computer.
4) During measurement, the calculation is performed once within 10 s. Such as: collecting and calculating three PT data on the phase A in 0-10 s, collecting and calculating three PT data on the phase B in 10-20 s, and collecting and calculating three PT data on the phase C in 20-30 s; so far, 9 PT measurements are calculated. Wait for 30s and start the next cycle from phase a.
5)9 PT, actually 3 groups, each component A/B/C. The zero sequence current needs three simultaneous measurements on the A/B/C three phases. And then, aiming at the zero sequence current, adding a step in the measurement steps: three of 0-10 s A phases, three of 10 s-20 s B phases, three of 20 s-30 s C phases, and 30 s-40 s, the zero sequence current of the 1 st group (1 of A/B/C) is measured and calculated, the 2 nd group of 40s-50s, and the 3 rd group of 50 s-60 s. Wait for 30s and start the next cycle.
6) The frequency of the trigger signal is 50Hz, the occurrence moment of the trigger pulse can be set as a 0-phase point, and relevant data are recorded to count the discharge frequency n, the discharge amount q, the phase phi of discharge occurrence and the several cycles occurring in 1s in 50 power frequency periods (1 s).
7) Measuring and calculating the amplitudes and the phases of fundamental waves of each PT exciting current, 3 th harmonic waves and 5 th harmonic waves; and calculating the amplitudes of the fundamental wave, the 3 th harmonic wave and the 5 th harmonic wave of the zero-sequence current and the phase of the fundamental wave.
And directly sending the data under the condition that the network is normal. If the network is abnormal, it is stored in CF card (memory card) and sent out when the network is normal.
8) And displaying on an upper computer (a monitoring host).
9) The discharge pulses are subjected to Fast Fourier Transform (FFT) and classified by time-frequency Transformation.
10) Initially, based on the discharge pulse, a TF map (vector map) can be drawn.
Through the internal fault on-line monitoring scheme of the generator outlet voltage transformer, PT fault characteristic quantities can be accurately analyzed according to the development and change trend of the fault characteristic quantities, the emergency treatment time is greatly prolonged, and the turn-to-turn short circuit is effectively avoided.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, it should be noted that, for those skilled in the art, many modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (2)
1. An internal fault on-line monitoring system of a generator outlet voltage transformer is characterized by comprising a high-precision micro-current sensor, a data acquisition unit and a monitoring host, wherein the high-precision micro-current sensor is sleeved on grounding wires of three groups of voltage transformers at the outlet of a generator in a core-through mode and is used for measuring the exciting currents of the three groups of voltage transformers at the outlet of the generator and transmitting the measured exciting current data to the data acquisition unit for processing; each group of voltage transformers consists of three voltage transformers which are respectively connected with three-phase voltage of the generator;
the monitoring host is connected with the data acquisition unit and used for calculating the amplitude and the phase of the exciting current of each group of voltage transformers based on the exciting current data processed by the data acquisition unit, obtaining a vector diagram of the voltage transformers, performing fault judgment according to the vector sum of the vector diagram, the development change trend and the mutation quantity condition, judging that the group of voltage transformers are normal if the vector sum of the vector diagram is zero, and judging that the group of voltage transformers have turn-to-turn short circuit if the vector sum of the vector diagram is not zero;
the monitoring host is also used for carrying out fault judgment by combining synchronous sampling data of exciting currents of in-phase voltage transformers in the three groups of voltage transformers;
the internal fault on-line monitoring process of the generator outlet voltage transformer comprises the following steps:
1) measuring the exciting current of 9 PT, three phases A/B/C, and 3 PT on each phase;
2) 3 paths of AD are adopted, 3 synchronous measurements of the same phase are carried out, and after one-phase measurement is finished, an analog switch is used for switching to the other phase;
3) 3 PTs on the same phase were measured each time; firstly, measuring 3 pieces on the phase A; after 10s, 3 on B were measured; after 10 seconds, measuring 3 pieces on the phase C, after 9 pieces are measured, after 30 seconds, restarting a cycle;
4) during measurement, the calculation is carried out once within 10 s; collecting and calculating three PT data on the phase A in 0-10 s, collecting and calculating three PT data on the phase B in 10-20 s, and collecting and calculating three PT data on the phase C in 20-30 s; at this point, 9 PT measurement and calculation are finished, 30s of waiting are carried out, and then the next cycle is started from the phase A;
5) the zero sequence current needs three simultaneous measurements on the A/B/C three phases; measuring and calculating the 1 st group of zero sequence current, 40s-50s 2 nd group and 50 s-60 s 3 rd group by using three phases of 0-10 s A, three phases of 10 s-20 s B and three phases of 20 s-30 s C for 30 s-40 s; waiting for 30s, and starting the next cycle;
6) the frequency of the trigger signal is 50Hz, the occurrence moment of the trigger pulse is set as a 0 phase point, and relevant data are recorded to count the discharge frequency n, the discharge quantity q, the phase phi of discharge and the number of cycles appearing in 1s in 50 power frequency periods;
7) measuring and calculating the amplitudes and the phases of fundamental waves of each PT exciting current, 3 th harmonic waves and 5 th harmonic waves; calculating amplitudes of zero-sequence current fundamental waves, 3-order harmonic waves and 5-order harmonic waves and fundamental wave phases;
8) displaying the measurement data on the monitoring host;
9) performing FFT on each discharge pulse, and classifying through time-frequency transformation;
10) based on the discharge pulse, a TF plot is drawn.
2. The on-line monitoring system for internal faults of the generator outlet voltage transformer as claimed in claim 1, wherein the monitoring host is further configured to alarm and prompt a condition that a turn-to-turn short circuit is determined to occur.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811165640.2A CN109375134B (en) | 2018-10-08 | 2018-10-08 | Generator outlet voltage transformer internal fault on-line monitoring method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811165640.2A CN109375134B (en) | 2018-10-08 | 2018-10-08 | Generator outlet voltage transformer internal fault on-line monitoring method and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109375134A CN109375134A (en) | 2019-02-22 |
| CN109375134B true CN109375134B (en) | 2022-02-01 |
Family
ID=65403019
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811165640.2A Expired - Fee Related CN109375134B (en) | 2018-10-08 | 2018-10-08 | Generator outlet voltage transformer internal fault on-line monitoring method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109375134B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112526306B (en) * | 2020-11-24 | 2022-11-04 | 中国大唐集团科学技术研究院有限公司火力发电技术研究院 | Generator outlet side voltage transformer insulation state monitoring system |
| CN114325466B (en) * | 2021-11-25 | 2022-11-18 | 中国大唐集团科学技术研究院有限公司火力发电技术研究院 | Generator outlet mutual inductor turn-to-turn short circuit self-checking system |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0248320A1 (en) * | 1986-06-05 | 1987-12-09 | Siemens Aktiengesellschaft | Fault current detector |
| JPH1169607A (en) * | 1997-08-14 | 1999-03-09 | Yaskawa Electric Corp | Ground-fault protective system |
| CN100371722C (en) * | 2005-09-22 | 2008-02-27 | 南京伏安电力设备有限公司 | Three-phase lightning protector early fault on-line monitoring method and apparatus thereof |
| US7567881B2 (en) * | 2007-03-30 | 2009-07-28 | General Electric Company | Self-adjusting voltage filtering technique compensating for dynamic errors of capacitive voltage transformers |
| KR101079848B1 (en) * | 2010-09-09 | 2011-11-03 | 한국전력공사 | Power metering device and method for correcting error of mof |
| CN102435903B (en) * | 2011-11-14 | 2013-11-13 | 国网电力科学研究院 | Online monitoring device for turn-to-turn short circuit of voltage transformer |
| CN104808105B (en) * | 2014-01-27 | 2017-10-13 | 南京南瑞继保电气有限公司 | The online method of discrimination of generator terminal voltage transformer turn-to-turn short circuit |
| CN105548799B (en) * | 2015-12-06 | 2019-01-11 | 国家电网公司 | The on-line monitoring method of generator motor rotor interturn short-circuit failure |
| CN106546873A (en) * | 2016-09-28 | 2017-03-29 | 深圳市惠立智能电力科技有限公司 | A kind of distribution singlephase earth fault Section Location and system |
| CN206541018U (en) * | 2017-01-18 | 2017-10-03 | 广州朗誉特电子科技有限公司 | A kind of multipoint grounding seeking instrument of voltage transformer |
| CN206618840U (en) * | 2017-03-30 | 2017-11-07 | 国家电网公司 | A kind of Exciting Windings for Transverse Differential Protection turn-to-turn short circuit monitoring device |
| KR101801611B1 (en) * | 2017-05-22 | 2017-11-27 | 스마트파워솔루션 주식회사 | Information technology system of adequacy verification for current transformer ratio and error bound of metering out fit |
| CN107884665B (en) * | 2017-11-28 | 2024-03-08 | 大唐西北(西安)电力试验研究院有限公司 | Device and method for preventing turn-to-turn short circuit of generator outlet voltage transformer from mistakenly tripping |
-
2018
- 2018-10-08 CN CN201811165640.2A patent/CN109375134B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN109375134A (en) | 2019-02-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103782509B (en) | For detecting system, computer program and the method for the internal winding failure of synchronous generator | |
| US7042229B2 (en) | System and method for on line monitoring of insulation condition for DC machines | |
| CN103728538B (en) | A kind of ground fault line selecting method of small current neutral grounding system | |
| CN109655713B (en) | Single-phase earth fault positioning method and system | |
| CN1333503C (en) | Protection and fault positioning method for generator stator winding single-phase earthing | |
| CN102768324A (en) | Single-phase ground fault section positioning method for low-current grounding system | |
| B. Kliman, WJ Premerlani, RA Koegl, D. Hoeweler | Sensitive, on-line turn-to-turn fault detection in AC motors | |
| CN106093714A (en) | The selection method of single-phase grounded malfunction in grounded system of low current circuit | |
| CN109375134B (en) | Generator outlet voltage transformer internal fault on-line monitoring method and system | |
| JP2004215478A (en) | Transmission line fault locator, transmission line fault locating method, transmission line fault locating program, and recording medium recording the program | |
| CN110031703A (en) | A kind of the unusual service condition method of discrimination and system of super extra-high voltage transformer | |
| CN111624444A (en) | Distribution line ground fault positioning method and device | |
| CN201740840U (en) | Earth fault phase identification device in three-phase unearthed system | |
| CN107179476B (en) | Distribution network fault distance measurement method | |
| CN111983419B (en) | Method and system for detecting diode faults in a multiphase brushless exciter rectifier | |
| CN103487725A (en) | Overhead distributing line ground fault indicating device based on zero-sequence component method | |
| CN109387724A (en) | Based on the lateral modified synchronous capacitor method for diagnosing faults of vertical analysis | |
| CN112014695A (en) | GIS equipment fault rapid positioning system and method | |
| US9018960B2 (en) | Method and device for enhancing the reliability of generator ground fault detection on a rotating electrical machine | |
| CN203587736U (en) | Overhead distributing line ground fault indicating device based on zero-sequence component method | |
| Pandarakone et al. | Online slight inter-turn short-circuit fault diagnosis using the distortion ratio of load current in a low-voltage induction motor | |
| CN111929630B (en) | Method and device for detecting saturation of current transformer | |
| CN113484683B (en) | Power distribution network fault positioning system and method based on transient information | |
| CN110783923B (en) | Transformer substation main transformer neutral point connection processing method and system | |
| CN108919040A (en) | Fault detection method, fault detection means and the electronic equipment of reactor winding |
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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20220201 |