CN110865279A - Single-phase earth fault positioning method based on neutral point earth current starting - Google Patents
Single-phase earth fault positioning method based on neutral point earth current starting Download PDFInfo
- Publication number
- CN110865279A CN110865279A CN201911256792.8A CN201911256792A CN110865279A CN 110865279 A CN110865279 A CN 110865279A CN 201911256792 A CN201911256792 A CN 201911256792A CN 110865279 A CN110865279 A CN 110865279A
- Authority
- CN
- China
- Prior art keywords
- neutral point
- current
- phase
- bus
- earth
- 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
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
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Locating Faults (AREA)
Abstract
The invention relates to a single-phase earth fault positioning method based on neutral point earth current starting, which introduces the measured current of a current transformer installed at a neutral point earth resistance of a bus of a transformer substation, namely the neutral point earth current, adopts the neutral point earth current as a single-phase earth fault abrupt change starting element, and a bus neutral point earth current starting device records the waveform of the neutral point earth current at an abrupt change moment T, transfers the three-phase current waveforms of all wide-area synchronous intelligent sensors installed along the outgoing line of the transformer substation at the same moment T and utilizes the information of wide-area synchronization on the bus neutral point earth current starting device to realize fault positioning. The method solves the problem of single-phase grounding fault location in the existing power distribution network small-resistance grounding system, particularly the medium-resistance and high-resistance grounding faults.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a single-phase earth fault positioning method based on neutral point earth current starting.
Background
With the high-speed development of national economy, the scale of an electric power system is getting bigger and bigger, the network structure becomes more and more complex, and the requirement of a user on the stability of power supply is higher and higher, which requires to continuously strengthen the upgrade of the electric power system, avoid the occurrence of faults in the running process of the system, and quickly and accurately find the position of the occurrence of the faults after the occurrence of the faults even if the faults occur, so as to quickly remove the faults, ensure the safe running of the electric power system and reduce the loss to the minimum.
Most of distribution networks in China generally adopt a low-current grounding mode that a neutral point is not grounded or is grounded through an arc suppression coil. When the small current grounding system has single-phase grounding fault, a short circuit loop is not formed, short circuit current with large magnitude causing equipment damage is not generated, voltage among three phase lines is still symmetrical voltage, normal work of a load is not influenced, and the small current grounding system can continue to operate for a period of time. Although this method has the advantage of high power supply reliability, after a single-phase earth fault occurs, the voltage of the sound phase to the ground is increased, the equipment insulation may be damaged in long-term operation, and arc overvoltage which is several times of rated voltage is generated when intermittent arc is grounded to directly break down the equipment insulation, thereby causing serious phase-to-phase fault. In order to reduce the damage of overvoltage to equipment, when a single-phase earth fault occurs in a system, a fault line and a fault point need to be found out as soon as possible to isolate the fault.
In the low-current grounding mode, when a grounding fault occurs, the fault current is relatively small, and particularly when the resistance of a grounding point is relatively large, the grounding current is weak and difficult to detect, so that the problem of fault positioning is brought, and the problem cannot be effectively solved.
Therefore, many lines are transformed into a low-resistance grounding mode, and the aim is to create obvious fault current by using a low resistance (generally 10-50 ohms) introduced by a neutral point to help effective positioning and protection of tripping. However, in practice, the zero sequence current protection (primary current 60A, 1s) of a common feeder line can only cut off the ground fault with the transition resistance below 100 ohms. The contact area of the wire end of the lead and the earth surface is small, the contact is not good, and the transition resistance of the lead is generally large and is about 180-260 ohms; when branches and vehicle suspension arms meet the lines, the transition resistance value is larger due to the trunk and the tires, and zero sequence protection does not act basically for the scenes.
Generally, fault indicators or sensors widely used for fault location are based on electric field abrupt starting or phase current abrupt starting, but this method has a major defect in principle, so that the practical effect is poor, and the main problems are that:
1) starting element is unreasonable
The electric field sudden change is used as a starting element of the ground fault, so that the starting element is easy to malfunction due to interference of external factors (environment, climate and overhead line arrangement mode) on one hand; more importantly, in a low-resistance grounding mode, the electric field change of the grounding point exceeding 100 ohms is very weak, and the fault judgment is difficult to start.
And the phase current abrupt change is used as a starting element of the ground fault, so that the starting threshold is difficult to set. The gate limit is high, and medium and high resistance grounding is difficult to start; the gate limits are low and false alarms are frequently triggered due to line seed loading or other disturbances, making practical use difficult.
2) Sampling frequency is too low
Common indicators or sensors have a sampling frequency that is too low, at most 4 kHz. In the actual occurrence of a ground fault, the frequency of the transient signal may be as high as 5kHz, and according to the nyquist sampling theorem, the sampling frequency above at least 10kHz can keep the original undistorted transient signal being acquired. Without high quality sample data, erroneous determination is easily caused.
3) The synchronization accuracy is too low
The synchronization accuracy of a common fault indicator or sensor can only reach 100 microseconds. The zero sequence current used for judging the grounding fault is synthesized by fault indicators respectively arranged on three-phase lines, and the error of the time synchronization phase between three phases brings the error of the synthesized zero sequence current. If the error of the synthesized zero-sequence current caused by the synchronization error is larger than the actual grounding zero-sequence current, the fault line selection and positioning errors are caused!
4) Local signals are mostly used, information is incomplete
The ordinary fault indicator or sensor mainly judges transient state or steady state zero sequence power based on local signals, which can not judge faults such as medium and high resistance grounding of a small resistance grounding system basically. Then, research is carried out to adopt similarity comparison based on zero sequence current of the upper part and the lower part of a fault point, which requires high-speed sampling and accurate synchronization of signals on two sides of the fault point. Under the condition of strict synchronization of signals, the zero-sequence current cross-correlation coefficient of two adjacent detection points on the same side of a fault point is close to 1, the zero-sequence current cross-correlation coefficient of the detection points on the two sides of the fault point is very small, and the characteristic can be utilized to determine a fault interval to realize line selection and positioning. Sampling is asynchronous, synchronous time error reaches several milliseconds, the calculated cross correlation coefficient is completely invalid, and at the moment, the algorithm fails, and a fault section cannot be determined. The synchronization precision between the conventional common fault indicators or sensors is too low to reach 10 milliseconds, and the fault location cannot be realized by using the algorithm.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a single-phase grounding fault positioning method based on neutral point grounding current starting, which aims to solve the problem of single-phase grounding fault positioning in the existing power distribution network low-resistance grounding system, particularly medium-resistance and high-resistance grounding faults.
In order to achieve the purpose, the invention adopts the following technical scheme:
a single-phase earth fault positioning method based on neutral point earth current starting is characterized in that: the method comprises the steps of introducing measured current of a current transformer installed at a neutral point grounding resistor of a bus of the transformer substation, namely neutral point grounding current, adopting the neutral point grounding current as a single-phase grounding fault abrupt change starting element, recording neutral point grounding current waveforms at an abrupt change moment T by a bus neutral point grounding current starting device, calling three-phase current waveforms of all wide area synchronous intelligent sensors installed along an outgoing line of the transformer substation at the same moment T, and utilizing wide area synchronous information to realize fault positioning on the bus neutral point grounding current starting device.
Preferably, the single-phase earth fault location method based on neutral point earth current starting includes the following steps:
step 1: when a single-phase earth fault occurs, capturing the sudden change of the neutral point earth current by the bus neutral point earth current starting device, and recording the time T of the sudden change and the waveform of the neutral point earth current at the corresponding time;
step 2: the neutral point grounding current starting device initiates a wave-recording action, and three-phase current waveforms and neutral point grounding current waveforms at the same time T are obtained from all wide-area synchronous intelligent sensors on a circuit and have the same time T;
and step 3: the bus neutral point grounding current starting device synthesizes a zero sequence current waveform based on the three-phase current waveform, and realizes fault positioning by using a fault judgment system.
Preferably, the single-phase earth fault location method based on neutral point earth current starting is characterized in that: and after the step 3, uploading the fault positioning result and the related wave recording waveform to a distribution automation master station or an internet of things cloud platform by the bus neutral point grounding current starting device.
Preferably, in the single-phase earth fault location method based on neutral point earth current starting, the bus neutral point earth current starting device uses the information of wide-area synchronization to retrieve the information of the three-phase current waveforms of each measurement point and the information of the neutral point earth current waveform at the bus.
Preferably, in the single-phase earth fault positioning method based on neutral point earth current starting, the wide-area synchronous intelligent sensor is powered by induction self-energy-taking and is internally provided with a positioning navigation unit.
Preferably, according to the single-phase earth fault positioning method based on neutral point earth current starting, the sampling frequency of the wide-area synchronous intelligent sensor is not lower than 12.8kHz or 15.36kHz, and the sampling bit width is not lower than 16 bits.
Preferably, according to the single-phase earth fault positioning method based on neutral point earth current starting, the measurement accuracy of both the wide-area synchronous intelligent sensor and the neutral point earth current starting device is not lower than 0.5 level.
Preferably, according to the single-phase ground fault positioning method based on neutral point ground current starting, the bus neutral point ground current starting device is installed at a bus in a substation.
Preferably, according to the neutral point grounding current starting-based single-phase grounding fault positioning method, high-speed wireless communication is adopted between the wide-area synchronous intelligent sensor and the bus neutral point grounding current starting device to realize data transmission.
By the scheme, the invention at least has the following advantages:
1. the wide-area synchronous intelligent sensor adopts induction electricity taking, is completely self-powered, and does not need an external independent power supply. The wiring and the stay wire are not needed, the construction is time-saving and labor-saving, and the measurement data at any time can be obtained by installation at any place and any position.
2. The neutral point grounding current introduced by the invention is used as a reliable criterion for judging whether a distribution network system has a single-phase grounding fault or not, can be used as a recording starting moment of the single-phase grounding fault through a synchronization technology, and can accurately perform line selection and fault location through the condition of the whole network zero-sequence current at the moment, thereby thoroughly solving the problems that the electric field change is very weak and the alarm cannot be triggered when the grounding system with a transition resistor is grounded under a small-resistance grounding system; the problem of frequent false alarms due to line load or any other disturbance when three-phase current disturbance is taken as a starting condition is also avoided.
3. The sampling frequency of the wide-area synchronous intelligent sensor is not lower than 12.8kHz (50Hz power grid) or 15.36kHz (60Hz power grid), so that original transient signals can be restored without distortion.
4. The invention is based on a positioning navigation unit, comprises a global positioning system or a Beidou satellite navigation system, can realize automatic frequency calibration, and ensures that the synchronous error between the current of each measuring point of a line and the grounding current of a neutral point is not more than 20 microseconds. The error of the three-phase synthesized zero-sequence current is ensured to be small enough, and the fault current is not influenced; meanwhile, accurate upstream and downstream synchronization of fault points is guaranteed, and fault positioning can be achieved by adopting a cross-correlation algorithm.
5. The bus neutral point grounding current starting device and the wide area synchronous intelligent sensor support at least 1 hour of wave recording cache, and can eliminate the influence of communication interruption caused by short-time instability of a wireless network.
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
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic diagram illustrating the time of the initial transient sudden change in the ground fault according to the present invention.
Fig. 2 is a schematic diagram of the zero sequence current direction at the time of the ground fault according to the present invention.
Fig. 3 is a schematic diagram of a single-phase earth fault positioning method based on neutral point earth current starting according to the present invention.
Fig. 4 is a schematic diagram of a fault area location according to a first embodiment of the present invention.
Fig. 5a and 5b are waveform diagrams of the neutral grounding current and the synthesized zero-sequence current of the on-line sensor according to the first embodiment of the present invention, respectively.
Fig. 6 is a waveform of a fault region locating feature according to a first embodiment of 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.
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
Examples
As shown in figure 3 of the drawings,
a single-phase earth fault positioning method based on neutral point earth current starting is mainly applied to a system in which a neutral point is earthed through a small resistor. The neutral point grounding current is measured through a current transformer installed at a neutral point grounding resistor of a transformer substation bus, the neutral point grounding current is used as a single-phase grounding fault abrupt change starting element, a bus neutral point grounding current starting device 102 records the neutral point grounding current waveform at an abrupt change moment, the three-phase current waveforms of all wide area synchronous intelligent sensors 101 installed along the outgoing line of the transformer substation at the same moment are taken, and fault location is realized by utilizing wide area synchronous information on the bus neutral point grounding current starting device 102.
Fig. 2 is a schematic diagram of the zero sequence current direction at the time of the ground fault, where 1 is the zero sequence current of the non-fault line flowing from the bus to the line, 2 is the zero sequence current of the fault line flowing from the line to the bus, 3 is the zero sequence current of the fault line flowing from the bus to the line, and 4 is the zero sequence current of the fault line with the maximum amplitude and opposite direction to the non-fault line.
On the basis of the above embodiment, a single-phase earth fault positioning method based on neutral point earth current starting includes the following steps:
step 1: when a single-phase earth fault occurs, capturing the current mutation flowing through the neutral point earth resistor by the bus neutral point earth current starting device, and recording the time T of the mutation and the waveform of the neutral point earth current at the corresponding time;
step 2: the bus neutral point grounding current starting device initiates a wave-recording action, and three-phase current waveforms at the same time T and neutral point grounding current waveforms with the same time T are obtained from all wide-area synchronous intelligent sensors on a circuit;
and step 3: the bus neutral point grounding current starting device synthesizes a zero sequence current waveform based on the three-phase current waveform, and realizes fault positioning by using a fault judgment system.
And 4, step 4: the bus neutral point grounding current starting device uploads a fault positioning result and a related recording waveform to a distribution automation master station or an Internet of things cloud platform, guides a remote control intelligent switch to realize fault isolation, and ensures that power supply is recovered after line patrol and fault removal are arranged at the first time.
The bus neutral point grounding current starting device is arranged at a bus in a transformer substation.
The wide area synchronous intelligent sensor comprises a 3G/4G high-speed wireless communication module, so that the batch transmission of high-speed sampling data is realized, and the bandwidth problem of data transmission is solved.
The bus neutral point grounding current starting device utilizes the wide-area synchronous information to call the three-phase current waveform information of each measuring point and the neutral point grounding current waveform information at the bus.
The wide-area synchronous intelligent sensor adopts induction self-energy-taking power supply, and comprises a positioning navigation unit, so that automatic frequency calibration can be realized, and accurate synchronization of three-phase current among measurement points is guaranteed.
The positioning navigation unit is a global positioning system or a Beidou satellite navigation system.
The sampling frequency of the wide-area synchronous intelligent sensor is not lower than 12.8kHz (50Hz power grid) or 15.36kHz (60Hz power grid), and the sampling bit width is not lower than 16 bits.
The measurement precision of the wide-area synchronous intelligent sensor is not lower than 0.5 grade (0-100A: the measurement error is less than 0.5A; 100-630A: the measurement error is less than 0.5%).
The synchronous error between three phases of the wide-area synchronous intelligent sensor is less than 20 microseconds.
The wide-area synchronous error between the wide-area synchronous intelligent sensors installed at different positions is less than 20 microseconds.
The wide-area synchronous error between the wide-area synchronous intelligent sensors installed at different positions and the bus neutral point grounding current starting device is less than 20 microseconds.
The wide-area synchronous intelligent sensor and the bus neutral point grounding current starting device both support caching of 1-hour recording data.
The wide area synchronous intelligent sensor and the bus neutral point grounding current starting device realize data transmission by adopting high-speed wireless communication.
The fault judgment system mainly realizes fault positioning by similarity, namely, the zero sequence current of each sensor of the line is used for carrying out cross-correlation calculation to realize line selection and positioning, and simultaneously, a amplitude comparison algorithm is combined to assist line selection.
Example one
1. Referring to fig. 4, a substation is selected, and a bus neutral grounding current starting device and a wide-area synchronous intelligent sensor are respectively arranged on a bus and an outgoing line of the substation;
2. as shown in fig. 1 and fig. 5a, when a single-phase ground fault occurs, the bus neutral grounding current starting device captures an abrupt change of the neutral grounding current, and records an abrupt change time T and a neutral grounding current waveform corresponding to the abrupt change time;
3. as shown in fig. 5b, the bus neutral point grounding current starting device initiates a wave-recording and calling action, and three-phase current waveforms and neutral point grounding current waveforms at the same time T are obtained from all wide-area synchronous intelligent sensors on the line and have the same time labels;
4. the bus neutral point grounding current starting device firstly synthesizes zero-sequence current waveforms based on the three-phase current waveforms of each set of wide-area synchronous intelligent sensor;
the zero sequence current synthesis is calculated as follows:
Io＝(Ia+Ib+Ic)
wherein Io is a synthesized zero-sequence current; ia. Ib and Ic are A, B, C three-phase current waveforms of each set of wide-area synchronous intelligent sensor.
5. And selecting lines according to the zero sequence current of each outgoing line head end wide-area synchronous intelligent sensor, wherein the line selection method comprehensively uses a amplitude comparison method and a correlation method, and carries out self-adaption judgment according to the topology and the waveform characteristics of the line.
It is obvious from fig. 2 that the zero-sequence current waveform of L2 is in opposite phase with other lines, and is obviously dissimilar, so the fault line is L2.
The amplitude ratio method calculates the following formula:
in > - (I1+ I2+ … + Ij) (j! n, R is a reliability coefficient factor, and is generally set to a value greater than 3 In accordance with the characteristics of the small resistance ground system)
And if the zero sequence current of a certain outgoing line is greater than or equal to R times of the sum of all other outgoing line zero sequence currents, the outgoing line is a fault line.
The similarity comparison adopts a cross-correlation algorithm, and is specifically calculated as follows:
assuming that the total number of N outgoing lines is N, respectively calculating the steady-state zero sequence waveform I of each outgoing line0nAnd other outgoing lines I0kAnd normalization processing is performed as the correlation value of the line: corr (n), n represents the nth line
Wherein
In the formula (I), the compound is shown in the specification,
I0nand I1nThe synthesized zero sequence current waveforms of the wide area synchronous intelligent sensors respectively installed on the two line outgoing lines;
k represents the kth zero sequence current data;
and L is the recording data window length for similarity calculation.
Selecting the minimum value in Corr (n), and if the minimum value is close to-1 (an actual threshold can be set through parameters), determining the fault line; if the minimum value is close to 1 (the actual threshold can be set by the parameter), all lines are considered to be non-fault lines, and the fault is outside the coverage area.
6. After a fault line is selected, pairwise cross-correlation calculation is carried out on the wide-area synchronous intelligent sensor on the line, the correlation result is close to-1 (the actual threshold can be set through parameters), and the fault is positioned between two sets of fault indicators; the correlation result is close to 1 (the actual threshold can be set by parameters), and the fault is positioned behind the 2 nd set of fault indicators.
Referring to fig. 6, which is a zero sequence current waveform of three devices on the fault line, it is obvious that the second and third devices are completely dissimilar, so that the fault point is between the second and third devices.
In the formula I0nAnd I1nRespectively synthesizing zero sequence current waveforms of two adjacent sets of wide area synchronous intelligent sensors;
k represents the kth zero sequence current data;
and L is the recording data window length for similarity calculation.
The neutral point grounding current starting device uploads a fault positioning result and a recording waveform to a power distribution automation master station or an Internet of things cloud platform, guides a remote control intelligent switch to realize fault isolation, and arranges to recover power supply after line patrol and fault removal at the first time.
The invention has at least the following advantages:
1. the wide-area synchronous intelligent sensor adopts induction electricity taking, is completely self-powered, and does not need an external independent power supply. The wiring and the stay wire are not needed, the construction is time-saving and labor-saving, and the measurement data at any time can be obtained by installation at any place and any position.
2. The neutral point grounding current introduced by the invention is a reliable criterion for judging whether a small-resistance grounding system has a single-phase grounding fault or not, can be used as the recording starting time of the single-phase grounding fault through a synchronization technology, and can accurately carry out line selection and fault location through the condition of the whole-network zero-sequence current at the moment, thereby thoroughly solving the problems that the electric field change is very weak and the alarm cannot be triggered when the small-resistance grounding system is grounded with a transition resistor; the problem of frequent false alarms due to line load or any other disturbance when three-phase current disturbance is taken as a starting condition is also avoided.
3. The sampling frequency of the wide-area synchronous intelligent sensor is not lower than 12.8kHz (50Hz power grid) or 15.36kHz (60Hz power grid), so that original transient signals can be restored without distortion.
4. The invention is based on a positioning navigation unit, comprises a global positioning system or a Beidou satellite navigation system, can realize automatic frequency calibration, and ensures that the synchronous error between the current of each measuring point of a line and the grounding current of a neutral point is not more than 20 microseconds. The error of the three-phase synthesized zero-sequence current is ensured to be small enough, and the fault current is not influenced; meanwhile, accurate synchronization of the upstream and the downstream of the fault point is guaranteed, and fault positioning can be realized by adopting similarity comparison.
5. The bus neutral point grounding current starting device and the wide area synchronous intelligent sensor support at least 1 hour of wave recording cache, and can eliminate the influence of communication interruption caused by short-time instability of a wireless network. A
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 (9)
1. A single-phase earth fault positioning method based on neutral point earth current starting is characterized in that: the method comprises the steps of introducing measured current of a current transformer installed at a neutral point grounding resistor of a bus of the transformer substation, namely neutral point grounding current, adopting the neutral point grounding current as a single-phase grounding fault abrupt change starting element, recording neutral point grounding current waveforms at an abrupt change moment T by a bus neutral point grounding current starting device, calling three-phase current waveforms of all wide area synchronous intelligent sensors installed along an outgoing line of the transformer substation at the same moment T, and utilizing wide area synchronous information to realize fault positioning on the bus neutral point grounding current starting device.
2. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 1, characterized by comprising the following steps:
step 1: when a single-phase earth fault occurs, capturing the sudden change of the neutral point earth current by the bus neutral point earth current starting device, and recording the time T of the sudden change and the waveform of the neutral point earth current at the corresponding time;
step 2: the neutral point grounding current starting device initiates a wave-recording action, and three-phase current waveforms and neutral point grounding current waveforms at the same time T are obtained from all wide-area synchronous intelligent sensors on a circuit and have the same time T;
and step 3: the bus neutral point grounding current starting device synthesizes a zero sequence current waveform based on the three-phase current waveform, and realizes fault positioning by using a fault judgment system.
3. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 2, characterized in that: and after the step 3, uploading the fault positioning result and the related wave recording waveform to a distribution automation master station or an internet of things cloud platform by the bus neutral point grounding current starting device.
4. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 1, characterized in that: the bus neutral point grounding current starting device utilizes the wide-area synchronous information to obtain the three-phase current waveform information of each measuring point and the neutral point grounding current waveform information at the bus.
5. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 1, characterized in that: the wide area synchronous intelligent sensor adopts induction self-energy-taking power supply and is internally provided with a positioning navigation unit.
6. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 1 or 5, characterized in that: the sampling frequency of the wide-area synchronous intelligent sensor is not lower than 12.8kHz or 15.36kHz, and the sampling bit width is not lower than 16 bits.
7. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 1, characterized in that: the measurement accuracy of the wide-area synchronous intelligent sensor and the neutral point grounding current starting device is not lower than 0.5 level.
8. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 1, characterized in that: the bus neutral point grounding current starting device is installed at a bus in a transformer substation.
9. The single-phase earth fault positioning method based on neutral point earth current starting according to claim 1, characterized in that: and the wide area synchronous intelligent sensor and the bus neutral point grounding current starting device realize data transmission by adopting high-speed wireless communication.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911256792.8A CN110865279A (en) | 2019-12-10 | 2019-12-10 | Single-phase earth fault positioning method based on neutral point earth current starting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911256792.8A CN110865279A (en) | 2019-12-10 | 2019-12-10 | Single-phase earth fault positioning method based on neutral point earth current starting |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110865279A true CN110865279A (en) | 2020-03-06 |
Family
ID=69658699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911256792.8A Pending CN110865279A (en) | 2019-12-10 | 2019-12-10 | Single-phase earth fault positioning method based on neutral point earth current starting |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110865279A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112068030A (en) * | 2020-09-27 | 2020-12-11 | 安徽江淮汽车集团股份有限公司 | Fault detection method, equipment, storage medium and device of grounding system |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1282876A (en) * | 2000-09-15 | 2001-02-07 | 清华大学 | Method and equipment for positioning failure point on electric power transmission line |
| CN1397807A (en) * | 2002-08-16 | 2003-02-19 | 华中科技大学 | Method for positioning grounding failure region of feed line in low-current grounding system |
| CN101261304A (en) * | 2008-04-25 | 2008-09-10 | 山东大学 | Low current grounding system distribution circuit single-phase earth fault automatic position setting method |
| CN101726692A (en) * | 2009-12-14 | 2010-06-09 | 辽宁省电力有限公司锦州供电公司 | Single-phase ground fault positioning method for ground protective device of low-current system |
| CN102253307A (en) * | 2011-04-19 | 2011-11-23 | 中国电力科学研究院 | Method for positioning single-phase grounding failure of distribution network containing distributed power supply |
| CN102778636A (en) * | 2012-07-26 | 2012-11-14 | 北京飞举电气有限公司 | Single-phase ground fault location method and apparatus |
| CN102914725A (en) * | 2012-07-20 | 2013-02-06 | 王道龙 | Medium-voltage power distribution network fault monitoring device |
| CN103267928A (en) * | 2013-04-27 | 2013-08-28 | 王鹏 | Low-current system single-phase earth fault line selection control circuit |
| CN106370914A (en) * | 2016-09-26 | 2017-02-01 | 武汉科技大学 | Zero sequence current carrier signal generating device and signal transmission method |
| CN107561405A (en) * | 2017-08-10 | 2018-01-09 | 国网山东省电力公司烟台供电公司 | A kind of failure line selection localization method and system based on non-contact sensing device |
| CN109462452A (en) * | 2018-10-26 | 2019-03-12 | 科大智能电气技术有限公司 | A method of improving transient state recording type fault detector sample-synchronous precision |
| CN110426593A (en) * | 2019-08-22 | 2019-11-08 | 苏州银蕨电力科技有限公司 | A kind of method for locating single-phase ground fault based on residual voltage starting |
-
2019
- 2019-12-10 CN CN201911256792.8A patent/CN110865279A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1282876A (en) * | 2000-09-15 | 2001-02-07 | 清华大学 | Method and equipment for positioning failure point on electric power transmission line |
| CN1397807A (en) * | 2002-08-16 | 2003-02-19 | 华中科技大学 | Method for positioning grounding failure region of feed line in low-current grounding system |
| CN101261304A (en) * | 2008-04-25 | 2008-09-10 | 山东大学 | Low current grounding system distribution circuit single-phase earth fault automatic position setting method |
| CN101726692A (en) * | 2009-12-14 | 2010-06-09 | 辽宁省电力有限公司锦州供电公司 | Single-phase ground fault positioning method for ground protective device of low-current system |
| CN102253307A (en) * | 2011-04-19 | 2011-11-23 | 中国电力科学研究院 | Method for positioning single-phase grounding failure of distribution network containing distributed power supply |
| CN102914725A (en) * | 2012-07-20 | 2013-02-06 | 王道龙 | Medium-voltage power distribution network fault monitoring device |
| CN102778636A (en) * | 2012-07-26 | 2012-11-14 | 北京飞举电气有限公司 | Single-phase ground fault location method and apparatus |
| CN103267928A (en) * | 2013-04-27 | 2013-08-28 | 王鹏 | Low-current system single-phase earth fault line selection control circuit |
| CN106370914A (en) * | 2016-09-26 | 2017-02-01 | 武汉科技大学 | Zero sequence current carrier signal generating device and signal transmission method |
| CN107561405A (en) * | 2017-08-10 | 2018-01-09 | 国网山东省电力公司烟台供电公司 | A kind of failure line selection localization method and system based on non-contact sensing device |
| CN109462452A (en) * | 2018-10-26 | 2019-03-12 | 科大智能电气技术有限公司 | A method of improving transient state recording type fault detector sample-synchronous precision |
| CN110426593A (en) * | 2019-08-22 | 2019-11-08 | 苏州银蕨电力科技有限公司 | A kind of method for locating single-phase ground fault based on residual voltage starting |
Non-Patent Citations (1)
| Title |
|---|
| 张志霞: "《小电流接地***单相接地故障选线理论研究》", 30 April 2014 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112068030A (en) * | 2020-09-27 | 2020-12-11 | 安徽江淮汽车集团股份有限公司 | Fault detection method, equipment, storage medium and device of grounding system |
| CN112068030B (en) * | 2020-09-27 | 2021-05-28 | 安徽江淮汽车集团股份有限公司 | Fault detection method, equipment, storage medium and device of grounding system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9823637B2 (en) | Fault detection and isolation using a common reference clock | |
| US8861155B2 (en) | High-impedance fault detection and isolation system | |
| Saha et al. | Fault location on power networks | |
| SE536143C2 (en) | Method for detecting earth faults in three-phase electric power distribution network | |
| CN110426593A (en) | A kind of method for locating single-phase ground fault based on residual voltage starting | |
| CN104166067A (en) | Single-phase earth fault positioning detection method and device | |
| CN101943737A (en) | Single-phase earth fault diagnosis method and device | |
| CN106093714A (en) | The selection method of single-phase grounded malfunction in grounded system of low current circuit | |
| US20240044965A1 (en) | Parameter independent traveling wave-based fault location using unsynchronized measurements | |
| CN112534280A (en) | System and method for locating faults on a multi-phase electrical network using positive and negative sequence voltage variations | |
| CN111007355A (en) | Disconnection fault detection method based on wide-area synchronous intelligent sensor | |
| JP6624165B2 (en) | Distribution line fault location system | |
| CN110865279A (en) | Single-phase earth fault positioning method based on neutral point earth current starting | |
| US20230194580A1 (en) | System and method for management of electric grid | |
| Fluty et al. | Electric transmission fault location techniques using traveling wave method and discrete wavelet transform | |
| CN103487724A (en) | Single-phase ground fault positioning method of power distribution network | |
| EP1599738B1 (en) | Detection of earth faults in three phase systems | |
| CN103454561B (en) | A kind of one-phase earthing failure in electric distribution network localization method | |
| CN219552575U (en) | Intelligent distribution network fault monitoring system | |
| Saha et al. | Fault location–Basic concept and characteristic of methods | |
| Lv et al. | A Method for Medium Voltage Underground Cables Incipient Faults Diagnosis and Location Using Sheath Current | |
| CN117406017A (en) | Method and device for positioning faults of power distribution network | |
| Seyedi et al. | Impedance Differential Protection for Double Circuit transmission Lines Based on Distributed Parameters | |
| JP3013487B2 (en) | Fault location method | |
| Li et al. | High-Speed Single-Ended DC Line Protection for the VSC-HVDC Grid |
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 |