CN113933644A - Power transmission line asymmetric fault positioning method free of influence of line parameters - Google Patents
Power transmission line asymmetric fault positioning method free of influence of line parameters Download PDFInfo
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- CN113933644A CN113933644A CN202010672871.3A CN202010672871A CN113933644A CN 113933644 A CN113933644 A CN 113933644A CN 202010672871 A CN202010672871 A CN 202010672871A CN 113933644 A CN113933644 A CN 113933644A
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- 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
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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- 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
Abstract
The invention provides a method for positioning an asymmetric fault of a power transmission line without being influenced by line parameters, which is based on a positive sequence fault component network and a negative sequence fault component network. The line parameters are actually influenced by line load and weather, so that the accurate values of the parameters in the actual running state of the line are difficult to obtain.
Description
Technical Field
The invention relates to the technical field of power system relay protection, in particular to a power transmission line asymmetric fault positioning method which is not influenced by line parameters and is based on positive and negative sequence fault component networks.
Background
The fault location technology of the high-voltage transmission line plays an increasingly important role in modern transmission line protection schemes, the fault location technology can calculate the distance between a fault position and a given reference point, and if the precision of the fault location technology is high enough, the maintenance time of the line after the fault is greatly prolonged, and the power failure time is shortened.
Conventional single-ended fault location techniques utilize single-ended measurements to calculate line impedance values from a fault point to a reference point, and utilize line parameters to convert the impedance values to fault distance values. When a ground fault occurs, the single-ended fault location technology needs to calculate the fault distance by using the line zero sequence parameters which are difficult to accurately obtain, and the precision of the single-ended fault location technology is greatly influenced by the interphase zero sequence coupling of the line and the transition resistance during the fault.
The traditional double-end fault location technology utilizes synchronous or asynchronous sampling data at two sides of a line, has higher precision than that of a single-end fault location technology, is not influenced by transition resistance, and has the defect that the fault position still needs to be obtained by utilizing the positive sequence parameter and the line length of the line. However, even if line parameters are available, their values vary with line load and weather conditions. Along with the higher and higher requirements of the modern society on power supply reliability and rapid power supply restoration after line faults, the higher requirement is also brought to the precision of the fault positioning technology of the power transmission line.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method for positioning the asymmetric fault of the power transmission line, which is not influenced by line parameters; the method for positioning the asymmetrical fault of the power transmission line, which is not influenced by line parameters and is based on the positive-sequence fault component network and the negative-sequence fault component network, provided by the invention comprises the following steps:
step S1: obtaining three-phase voltage and current instantaneous values of two sides of synchronously detected power transmission line
Extracting and calculating line fault components to obtain fault components of three-phase voltage and current at two sides of the line
；
Step S2: dividing the fault components of three-phase current at two sides of the line
(ii) a Performing differential filtering to suppress attenuated DC component in fault current to obtain
；
；
Step S3: will be provided with
，
Performing full-wave Fourier transform to obtain corresponding fundamental frequency phasor form
，
Step S4: will be provided with
Carrying out amplitude and phase compensation calculation to obtain fundamental frequency phasor of three-phase current fault components on two sides of the line
；
Step S5: will be provided with
，
Filtering sequence calculation is carried out to obtain positive and negative sequence fault components of voltage and current at two sides of the line
；
；
Step S6: the positive and negative sequence fault component networks established after the power transmission line has the asymmetric short-circuit fault are formed by the positive and negative sequence fault components of the voltage and the current on two sides of the line
，
A system of equations for fault location can be written, and solving the system of equations results in a fault location solution that is independent of line parameters.
Preferably, the line frequency fault component is used in step S1 to avoid the effect of fault transition resistance.
Preferably, the attenuated dc component in the fault current is suppressed by differential filtering in step S2 to improve the positioning accuracy.
Preferably, the original fault component current phasor is obtained by performing amplitude and phase compensation on the differential filtered fault component current phasor in step S4.
Preferably, in step S6, a voltage balance equation is established in the positive and negative sequence fault component networks by the positive and negative sequence fault components of the voltage and current on both sides of the line, and a fault position solution independent of line parameters is solved by forming an equation set in a simultaneous manner.
Preferably, the method for solving the fault component includes:
where t is time.
Preferably, the differential filtering method is as follows:
where t is time.
Preferably, the method for obtaining the original fault component current from the fault component current after the differential filtering through the compensation algorithm is as follows:
preferably, the method for establishing the voltage balance equation in the positive and negative sequence fault component networks through the positive and negative sequence fault components of the voltage and the current on the two sides of the line and forming an equation set to solve the fault position solution irrelevant to the line parameters in a simultaneous manner comprises the following steps:
compared with the prior art, the invention has the following beneficial effects: the invention utilizes the positive and negative sequence fault component networks to prevent the fault location of the transmission line from being influenced by the transition resistance; the invention inhibits the influence of the attenuation direct current component in the fault current through differential filtering so as to improve the positioning precision; according to the invention, through the combined application of the positive sequence fault component and the negative sequence fault component, the fault positioning result does not depend on any line parameter, the change of the line parameter in different running states does not influence the fault positioning precision, and the method has stronger robustness and higher precision.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
fig. 1 is a schematic diagram of a dual power supply system used in the asymmetric fault location method of a power transmission line, which is not affected by line parameters and is based on positive and negative sequence fault component networks, in the invention, wherein S represents a transmitting end, R represents a receiving end, and the length of the line is 400 km;
FIG. 2 is a schematic diagram of transition resistance of the dual power supply system of the present invention in the event of various asymmetric faults on the transmission line, wherein
Is an arc resistance of the phase-to-phase fault,
a transition resistance to ground fault;
FIG. 3 is a network diagram of a positive sequence fault component when an asymmetric fault occurs on a power transmission line in a dual power supply system of the present invention;
FIG. 4 is a network diagram of the negative sequence (fault) component of the dual power system of the present invention when an asymmetric fault occurs on the transmission line;
fig. 5 (a) is a simulation diagram of the dual power supply system of the present invention when a single-phase ground fault occurs on a transmission line 80 kilometers away from a transmission-side bus,
is 100 ohms;
fig. 5 (b) is a simulation diagram of the dual power supply system of the present invention when a two-phase short circuit occurs on the power transmission line 80 km away from the transmitting end,
is 100 ohms;
FIG. 5 (c) is a simulation diagram of the dual power supply system of the present invention when a two-phase ground short circuit occurs on a transmission line 80 km away from a transmitting end, the arc resistance
The number of the holes can be ignored,
is 100 ohms.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
At present, a fault location algorithm of a high-voltage transmission line is a hot point of research of scholars at home and abroad at present, and in order to obtain a relatively accurate fault location, accurate line parameters need to be obtained for calculating the fault location. Compared with the traditional method, the invention establishes the balance equation of the positive sequence voltage and the negative sequence voltage through the positive sequence fault component network and the negative sequence fault component network established after the line has the asymmetric fault, thereby obtaining the fault position solution which is completely independent of the line parameters and the length, and having the characteristics of no influence of the line parameters, strong robustness and high precision.
Fig. 1 is a schematic diagram of a dual power supply system used in the asymmetric fault location method of a power transmission line not affected by line parameters based on positive and negative sequence fault component networks, wherein S denotes a transmitting end, R denotes a receiving end, F denotes a fault point, and the line length is 400 km; as shown in fig. 1, the method for locating an asymmetric fault of a power transmission line, which is not affected by line parameters and is based on a positive-sequence fault component network and a negative-sequence fault component network, provided by the invention, comprises the following steps:
step S1: obtaining three-phase voltage and current instantaneous values of two sides of synchronously detected power transmission line
Extracting and calculating fault components to obtain the fault components of three-phase voltage and current at two sides of the line
；
Step S2: dividing the fault components of three-phase current at two sides of the line
(ii) a Performing differential filtering to suppress attenuated DC component in fault current to obtain
；
；
Step S3: will be provided with
，
Performing full-wave Fourier transform to obtain corresponding fundamental frequency phasor form
；
Step S4:
carrying out amplitude and phase compensation calculation to obtain fundamental frequency phasor of three-phase current fault components at two sides of the line
；
Step S5: will be provided with
，
Filtering sequence calculation is carried out to obtain positive and negative sequence fault components of voltage and current at two sides of the line
，
；
Step S6: the positive and negative sequence fault component networks established after the power transmission line has the asymmetric short-circuit fault are formed by the positive and negative sequence fault components of the voltage and the current on two sides of the line
，
A system of equations for fault location can be written, and solving the system of equations results in a fault location solution that is independent of line parameters.
In this embodiment, the asymmetric fault considers transition resistances of different fault types, and fig. 2 is a schematic diagram of transition resistances of a dual power supply system in the present invention when various asymmetric faults occur on a transmission line, where
Is an arc resistance of the phase-to-phase fault,
the transition resistance for a ground fault.
Fig. 3 is a network diagram of a positive sequence fault component when an asymmetric fault occurs on a transmission line in the dual power supply system of the present invention. Such asFIG. 3 shows a schematic view of a
The power source of the transmitting side is equivalent to positive sequence impedance;
is the positive sequence fault component current of the transmitting side;
is a line unit length positive sequence impedance;
the distance from the fault point to the bus at the transmitting side;
the total length of the line;
is the receiving side positive sequence fault component current;
the receiving side power supply is equivalent to positive sequence impedance;
the positive sequence fault component voltage is the bus positive sequence fault component voltage of the sending side;
the virtual power supply at the fault point has the amplitude equal to the voltage amplitude of the special phase at the fault point before the fault occurs, and the phase is opposite to the voltage phase of the special phase at the fault point before the fault occurs;
an additional impedance associated with the fault type in the positive sequence fault component network;
to receive the side bus positive sequence component voltage. The voltage balance equations in the positive sequence fault component network after an asymmetric fault occurs can be written from fig. 3:
fig. 4 is a network diagram of a negative sequence fault component when an asymmetric fault occurs on a transmission line in the dual power supply system of the present invention. As shown in fig. 4, in which
The equivalent negative sequence impedance is the power supply of the transmitting side;
is the transmit side negative sequence (fault) component current;
is the negative sequence impedance of the line unit length;
the distance from the fault point to the bus at the transmitting side;
the total length of the line;
is the receive side negative sequence (fault) component current;
the equivalent negative sequence impedance of the receiving side power supply;
is the negative sequence (fault) component voltage of the transmitting side bus;
to take placeNegative sequence voltage at a fault point when a fault occurs symmetrically;
is an arc light resistor;
to accept the side bus negative sequence fault component voltage. The voltage balance equation in the negative sequence (fault) component network after an asymmetric fault occurs can be written from fig. 4:
FIG. 5 is a simulation of different fault types with transition resistance according to the method of the present invention.
In the embodiment, aiming at the problem of inaccurate positioning caused by the fact that the line parameters are difficult to accurately obtain in the traditional single-ended or double-ended fault positioning algorithm based on the line parameters, the method for simultaneously solving the network voltage balance equation based on the positive sequence fault component and the negative sequence fault component is adopted, the fault positioning method completely unrelated to the line parameters is obtained, and the fault current differential filtering inhibits the attenuation direct current component of the fault current differential filtering and improves the positioning precision.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (9)
1. A method for positioning the asymmetric fault of the transmission line without being influenced by line parameters is characterized by comprising the following steps:
step S1: obtaining three-phase voltage and current instantaneous values of two sides of synchronously detected power transmission line
Extracting and calculating fault components to obtain the fault components of three-phase voltage and current at two sides of the line
；
Step S2: dividing the fault components of three-phase current at two sides of the line
(ii) a Performing differential filtering to suppress attenuated DC component in fault current to obtain
，
；
Step S3: the process of the preparation of the compound comprises the following steps of,
，
performing fast Fourier transform to obtain corresponding fundamental frequency phasor form
；
Step S4: will be provided with
Carrying out amplitude and phase compensation calculation to obtain fundamental frequency phasor of three-phase current fault components on two sides of the line
；
Step S5: will be provided with
，
Filtering sequence calculation is carried out to obtain positive and negative sequence fault components of voltage and current at two sides of the line
；
Step S6: the positive and negative sequence fault component networks established after the power transmission line has the asymmetric short-circuit fault are formed by the positive and negative sequence fault components of the voltage and the current on two sides of the line
，
A voltage balance equation set for the fault location can be written, and solving the equation set can result in a fault location solution that is independent of the line parameters.
2. The method of claim 1, wherein the power frequency fault component is used in step S1 to avoid the influence of fault transition resistance.
3. The method for locating the asymmetric fault of the power transmission line, which is not influenced by the line parameters, according to claim 1, characterized in that in step S2, attenuated direct current components in the fault current are suppressed through differential filtering to improve the locating accuracy.
4. The method for locating the asymmetric fault of the transmission line, which is not affected by the line parameters, according to claim 1, wherein the original fault component current phasor is obtained by performing amplitude and phase compensation on the fault component current phasor obtained by filtering the difference in step S4.
5. The method for locating the asymmetric fault of the power transmission line, which is not affected by the line parameters, according to claim 1, wherein in step S6, a voltage balance equation is established in the positive and negative sequence fault component networks through the positive and negative sequence fault components of the voltage and the current on the two sides of the line, and an equation set is formed to solve the fault position solution independent of the line parameters in a simultaneous manner.
6. The method for positioning the asymmetric fault of the power transmission line, which is not influenced by the line parameters, according to claim 2, wherein the method for solving the fault component is as follows:
where t is time.
7. The method for locating the asymmetric fault of the power transmission line, which is not affected by the line parameters, according to claim 3, wherein the differential filtering method is as follows:
where t is time.
8. The method for locating the asymmetric fault of the power transmission line, which is not affected by the line parameters, according to claim 4, wherein the method for obtaining the original fault component current from the fault component current after the differential filtering through a compensation algorithm comprises the following steps:
9. the method for positioning the asymmetric fault of the power transmission line, which is not influenced by the line parameters, according to the claim 5, is characterized in that a method for establishing a voltage balance equation in a positive sequence fault component network and a negative sequence fault component network through positive sequence fault components and negative sequence fault components of voltage and current on two sides of the line, forming an equation set and simultaneously solving a fault position solution irrelevant to the line parameters comprises the following steps:
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101825678A (en) * | 2010-04-23 | 2010-09-08 | 华南理工大学 | Parameter adaptive failure distance measurement method for transmission line with four-circuit on single tower |
| CN103217623A (en) * | 2013-03-13 | 2013-07-24 | 福建省电力有限公司 | Fault location method for two ends of line irrelevant with transition resistance and load current |
| CN106330095A (en) * | 2016-09-27 | 2017-01-11 | 华北电力大学 | Large-scale photovoltaic power station's collection system fault location method |
| CN109283429A (en) * | 2018-09-25 | 2019-01-29 | 南方电网科学研究院有限责任公司 | A kind of Fault Location for Distribution Network method based on positive-negative sequence impedance principle |
| CN110518557A (en) * | 2019-04-08 | 2019-11-29 | 西安交通大学 | A kind of fault current limiter input control method based on short circuit current integrated information |
-
2020
- 2020-07-14 CN CN202010672871.3A patent/CN113933644A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101825678A (en) * | 2010-04-23 | 2010-09-08 | 华南理工大学 | Parameter adaptive failure distance measurement method for transmission line with four-circuit on single tower |
| CN103217623A (en) * | 2013-03-13 | 2013-07-24 | 福建省电力有限公司 | Fault location method for two ends of line irrelevant with transition resistance and load current |
| CN106330095A (en) * | 2016-09-27 | 2017-01-11 | 华北电力大学 | Large-scale photovoltaic power station's collection system fault location method |
| CN109283429A (en) * | 2018-09-25 | 2019-01-29 | 南方电网科学研究院有限责任公司 | A kind of Fault Location for Distribution Network method based on positive-negative sequence impedance principle |
| CN110518557A (en) * | 2019-04-08 | 2019-11-29 | 西安交通大学 | A kind of fault current limiter input control method based on short circuit current integrated information |
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|---|
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