CN109324269B - Distribution network single-phase line break fault identification method based on distributed measurement - Google Patents

Distribution network single-phase line break fault identification method based on distributed measurement Download PDF

Info

Publication number
CN109324269B
CN109324269B CN201811545634.XA CN201811545634A CN109324269B CN 109324269 B CN109324269 B CN 109324269B CN 201811545634 A CN201811545634 A CN 201811545634A CN 109324269 B CN109324269 B CN 109324269B
Authority
CN
China
Prior art keywords
fault
phase
voltage
distribution network
power distribution
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.)
Active
Application number
CN201811545634.XA
Other languages
Chinese (zh)
Other versions
CN109324269A (en
Inventor
邵志敏
王峰
李建修
刘洋
苏国强
刘合金
苏建军
孙勇
赵辰宇
董啸
李立生
张林利
张世栋
李沐
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Shandong Electric Power Co Ltd
Original Assignee
State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Shandong Electric Power Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by State Grid Corp of China SGCC, Electric Power Research Institute of State Grid Shandong Electric Power Co Ltd filed Critical State Grid Corp of China SGCC
Priority to CN201811545634.XA priority Critical patent/CN109324269B/en
Publication of CN109324269A publication Critical patent/CN109324269A/en
Application granted granted Critical
Publication of CN109324269B publication Critical patent/CN109324269B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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

Abstract

The invention discloses a distribution network single-phase line break fault identification method based on distributed measurement. The method comprises the following steps: step S1: a wide area measurement system is adopted to keep on-line monitoring on the power distribution network; step S2: when the fault is detected, judging whether the fault is a single-phase earth fault or a single-phase disconnection fault, if so, entering a step S3, otherwise, ending the fault identification; step S3: synchronously acquiring three-phase voltage data of one end of a fault point far away from a bus at the moment of the fault t by using a distributed measuring device in a wide area measuring system, and storing the acquired three-phase voltage data; step S4: calculating an included angle value theta between the sum of the voltage vectors of two phases which do not have faults and the voltage vector of the fault phase by using the stored three-phase voltage data; and, step S5: and identifying whether the fault is a single-phase disconnection fault or not based on the included angle value theta.

Description

Distribution network single-phase line break fault identification method based on distributed measurement
Technical Field
The invention relates to a power distribution network line fault identification method, in particular to a power distribution network single-phase line break fault identification method based on distributed measurement.
Background
The distribution network is directly connected with users, is an important component of an electric power system, and the running state of the distribution network is directly related to the power consumption quality and personal safety of the users. After the single-phase line break fault of the power distribution network occurs, obvious imbalance phenomenon occurs to the three-phase voltage at the downstream load side of the fault, three-phase power equipment such as a motor runs in a phase-lacking mode, and finally the three-phase power equipment is burnt out due to heating, so that serious economic loss is caused. Meanwhile, when single-phase disconnection faults occur, the single-phase disconnection faults are often accompanied with grounding faults, and the disconnection grounding faults are different from common single-phase grounding faults in a power distribution network, so that safety accidents such as electric shock of people and livestock, fire catching in mountain forests and the like are possibly caused, high dangerousness is realized, and great threat is brought to life and property safety of people.
At present, although many scholars are dedicated to fault identification by utilizing voltage and current characteristics of single-phase disconnection faults in a power distribution network, for example, university scholars in Shandong carry out more detailed analysis on three-phase sequence voltage and sequence current of single-phase disconnection faults under three different grounding conditions in research, and provide a criterion for identifying single-phase disconnection faults by adopting positive and negative sequence currents and variable quantities thereof, the resistance range of grounding transition resistors is not considered sufficiently, and the actual identification effect is not ideal.
In a power distribution network mainly based on a low-current grounding mode in China, because the electrical characteristics of a single-phase disconnection fault and a single-phase grounding fault on a power supply side are very similar, fault identification is difficult to perform by using a traditional centralized measuring device, the power distribution network can continuously operate for hours after the single-phase disconnection fault occurs, and the safe and reliable operation of the power distribution network is seriously threatened. Although single-phase disconnection faults and single-phase ground faults have power-supply-side electrical characteristics that are difficult to distinguish, the two faults have different voltage characteristics on the load side. According to the characteristic, in order to acquire fault information of a fault load side, distributed Measurement is carried out on the power distribution network based on a Wide Area Measurement System (WAMS), and fault identification is carried out on the basis.
The WAMS provides accurate time scales by a Global Positioning System (GPS), acquires current, voltage and frequency signals with high sampling rate and high precision, has the characteristics of phasor acquisition, synchronous acquisition and real-time data processing, and can be widely applied to various fields such as whole-network operation monitoring control, regional protection control, fault diagnosis, pollution source positioning and the like.
WAMS adopts a synchronous phase angle measurement technology, and arranges a Phasor Measurement Unit (PMU) at a key monitoring point of a power grid to realize synchronous acquisition of the phasor of the whole power grid. The PMU synchronously synchronizes time through the GPS technology, information with time scales is sent to the monitoring master station, and a dispatcher monitors the running state of the power grid in real time according to the synchronous information. The WAMS system is widely applied to a plurality of advanced operation analyses such as power system state estimation, power grid transient and steady state control, relay protection and automation control, fault diagnosis and fault location. The foreign research on the WAMS starts before and after 1990, and countries in the United states, Spain and the like successively research on the aspects of synchronous measurement, field application and the like of the WAMS; the research of China on the WAMS system starts in 2000, and research and development focuses on the design and use of a phasor measurement device.
On the basis of WAMS, the voltage of a load side at the downstream of a fault can be detected and analyzed through a distributed measuring device, and fault identification is carried out on the single-phase line break fault according to the voltage, so that the problem that the single-phase line break fault identification is difficult in the existing power distribution network is solved.
Disclosure of Invention
The invention mainly discloses a single-phase disconnection fault identification method based on a three-phase voltage vector included angle relation, which is mainly characterized in that a wide-area measurement system is utilized to synchronously measure three-phase voltages at a downstream load side of a fault, and the phase relation of the three-phase voltages at the load side is calculated and analyzed.
The invention provides a distribution network single-phase line break fault identification method based on distributed measurement, which is characterized by comprising the following steps: the distribution network single-phase line break fault identification method based on distributed measurement identifies single-phase line break faults based on the relation between three phase phases of voltage on a load side.
Preferably, the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement comprises the following steps:
step S1: a wide area measurement system is adopted to keep on-line monitoring on the power distribution network;
step S2: when the fault is detected, judging whether the fault is any one of single-phase earth fault or single-phase disconnection fault, if so, entering the following step S3, otherwise, ending the fault identification;
step S3: synchronously acquiring three-phase voltage data of one end of a fault point far away from a bus at the moment of the fault t by using a distributed measuring device in a wide area measuring system, and storing the acquired three-phase voltage data;
step S4: calculating an included angle value theta between the sum of the voltage vectors of two phases which do not have faults and the voltage vector of the fault phase by using the stored three-phase voltage data; and
step S5: identifying whether the fault is a single-phase wire break fault based on the included angle value theta.
Preferably, in step S2, when the fault is detected, the voltage and current data collected by the wide-area measurement system are used to perform section location on the fault according to a D-type traveling wave location method, and then the positive sequence, negative sequence, and zero sequence voltage and/or current data are obtained by using a symmetric component method, and whether the fault is a single-phase ground fault or a single-phase line break fault is determined according to the boundary condition between the single-phase ground fault and the single-phase line break fault.
Preferably, in step S2, the boundary condition between the single-phase earth fault and the single-phase line break fault is that the zero-sequence current after the fault is not zero, and the positive-sequence current and the negative-sequence current after the fault are both smaller than the current before the fault.
Preferably, in step S3, the voltage vectors of the three phases of the load side transformer are measured simultaneously by the distributed measurement device.
Preferably, in step S4, an angle value θ between the sum of the voltage vectors of two of the three phases that are not failed and the voltage vector of the failed phase is calculated by:
Figure BDA0001909264300000031
wherein x is1Abscissa of sum of voltage vectors for two phases without fault, x2Abscissa, y, of the voltage vector of the faulted phase1Ordinate, y, of the sum of the voltage vectors of the two phases which have not failed2The ordinate of the voltage vector of the faulted phase.
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, the coordinate value of the voltage vector of one of the two phases which do not have faults before the faults is defined as (0,1), the straight line where the voltage vector is located is used as a y axis, the vertical y axis is used as an x axis, a coordinate system is established, all the following vector calculations are calculated according to the coordinate system, and the calculation is performed according to the formula UAL＝EA+UNOAnd UBL＝EB+UNOCoordinate (x) of the sum of the voltage vectors of the two phases that have not failed is calculated1,y1) Wherein U isNOIs the system neutral point voltage, UALIs the voltage vector of one of the two phases which has not failed, EAIs the pre-fault system supply side voltage, U, of said one of the two phases that is not faultyBLIs the voltage vector of the other of the two phases which has not failed, EBIs the pre-fault system supply side voltage of the other of the two phases that is not faulty; the voltage vector of the faulted phase is calculated according to the following formula and converted into coordinates (x) in the established coordinate system2,y2)：
Figure BDA0001909264300000032
Wherein, UCLIs the voltage vector of the faulted phase, R0To ground transition resistance, ZKIs an equivalent impedance, UIAAnd UIBInput voltage, U, of a two-phase line-to-transformer without faultICIs the input voltage of the faulted phase line to the transformer.
Preferably, in step S4, the capacitance C-4 x 10 is distributed by assuming that the line is grounded-7(F) Total conductance Y K2 × j ω C, equivalent impedance Zk500(Ω), at different R0Value (0)<R0<10000) Under the condition, the system neutral point voltage U is calculated by the following formula (4)NO：
Figure BDA0001909264300000041
Wherein E isCIs the voltage on the power supply side of the system before fault, Y, of any of the three phasesKIs the total conductance of the three-phase system, C is the line-to-ground distributed capacitance of any one of the three phases, R0Is a ground transition resistance.
Preferably, in the above formula (7), for the Y-Y type transformer, ZK2Z, where Z is the resistance of any of the three phase windings.
Preferably, in the above formula (7), for the delta-Y type transformer, ZK(2/3) Z, where Z is the resistance of any of the three phase windings.
Preferably, in step S4, the matlab software is also used to log the included angle value theta10(R0) Formal ground transition resistance R0Is calculated.
Preferably, 0 will be<R0<Different R within 100000Value of included angle theta with log10(R0) Formal ground transition resistance R0The change of (a) is plotted to show the change.
Preferably, in step S5, when theta ≧ threshold thetakWhen the fault is a single-phase earth fault, when theta is<Threshold value thetakAnd if so, determining that the single-phase disconnection fault occurs.
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, the threshold value θ iskIs 10 deg..
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, the threshold value θ iskIs 8 deg..
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, when the included angle value theta is always greater than 10 degrees and follows log10(R0) Formal ground transition resistance R0When the voltage is increased, it is determined that a single-phase ground fault has occurred.
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, when the included angle value θ is always equal to zero, the single-phase disconnection fault is determined to occur.
Compared with the traditional identification method, the method has the advantages that the equivalent circuit models of the power side and the load side under different grounding conditions and different grounding transition resistance values are analyzed and calculated, the obtained fault identification method has better identification accuracy and wider application range, and a feasible and effective new scheme is provided for solving the problem of single-phase disconnection fault identification of the power distribution network.
Drawings
Fig. 1 is a diagram schematically showing an equivalent circuit of a single-phase ground fault system.
Fig. 2 is a diagram schematically showing an equivalent circuit of a Y-Y type transformer.
Fig. 3 is a diagram schematically showing an equivalent circuit of a delta-Y type transformer.
Fig. 4 is a diagram schematically showing a single-phase ground fault load-side voltage vector.
Fig. 5 is a diagram schematically showing a load-side voltage vector of a single-phase disconnection fault.
FIG. 6 shows the value of the included angle θ and the ground transition resistance R0A graph of the relationship.
Fig. 7 is a diagram schematically illustrating a single-loop power distribution network line simulation topology established in the embodiment.
FIGS. 8(a) to 8(c) are θ -R illustrating three sets of simulation faults in the embodiment0A graph of the relationship, wherein FIG. 8(a) is a graph of θ -R for the line 5-6 fault in FIG. 70A graph of relationships; FIG. 8(b) is a graph of θ -R for the line 2-3 fault of FIG. 70A graph of relationships; FIG. 8(c) is a graph of θ -R for line 12-13 fault correspondences0A graph of the relationship.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
When a single-phase earth fault occurs, assuming that the fault phase is the C-phase, the equivalent circuit of the system is as shown in fig. 1. Wherein N is the system neutral point, EA、EB、ECA, B, C phase pre-fault system supply side voltages, CA、CB、CCA, B, C phase line-to-ground distributed capacitances, Y, respectivelyKA、YKB、YKCAre respectively and CA、CB、CCGround conduction, R, on the right side of the parallel system0Is a ground transition resistance.
Setting the voltage of the neutral point of the system after the fault as UNOThen, according to the system neutral point voltage calculation formula, there are:
Figure BDA0001909264300000051
in formula (1): y isA、YB、YCA, B, C relative electrical sums, respectively.
From the equivalent circuit of fig. 1, the sum Y of the respective relative ground electric conductivities can be calculatedA、YB、YC：
Figure BDA0001909264300000052
Meanwhile, the line properties of the three phases of the system are assumed to be consistent, namely:
Figure BDA0001909264300000053
combining the formulas (1), (2) and (3), obtaining the neutral point voltage expression of the system:
Figure BDA0001909264300000054
the commonly used distribution transformer has two wiring modes of Y-Y type and delta-Y type.
For a Y-Y type transformer, the equivalent circuit is shown in FIG. 2, where UIA、UIB、UICA, B, C three-phase line-to-transformer three-phase input voltages, respectively; cA、CB、CCThe distributed capacitors are respectively the ground of the three-phase line; zA、ZB、ZCRespectively the three-phase winding resistance values of the transformer; r0Is a ground transition resistance.
Because the distribution network line distributes capacitance C to groundA、CB、CCVery small, the impedance converted according to the formula 1/j ω C is much larger than the impedance Z of the three-phase winding of the transformerA、ZB、ZCAnd ground transition resistance R0. Therefore, in this case, the calculation of the equivalent circuit of the transformer can be neglected to pass through CA、CBThe current flowing into earth, which is considered as open circuit, and R0And CCThe parallel resistance value can be regarded as R0. Meanwhile, the three-phase winding of the transformer is assumed to be symmetrical, namely the resistance value Z of the three-phase windingA＝ZB＝ZC＝Z1. The circuit of fig. 2 is calculated to obtain a primary side voltage value U of a C phase (i.e., a fault phase) of the Y-Y type transformerCL：
Figure BDA0001909264300000061
A similar analytical calculation is then carried out for a delta-Y type transformer (the equivalent circuit of which is shown in figure 3). U in the figureIA、UIB、UICA, B, C three phases respectivelyThree-phase input voltage, C, of the line-to-transformerA、CB、CCDistributed capacitance to ground, Z, of three-phase lines, respectivelyAB、ZBC、ZACThree-phase windings of the transformer respectively; r0Is a ground transition resistance. The influence of the distribution network line on the ground distribution capacitance is neglected in the same way, and the three-phase winding resistance value ZAB＝ZBC＝ZCA＝Z2. Obtaining a primary side voltage value U of the C phase (namely, a fault phase) of the delta-Y type transformerCL：
Figure BDA0001909264300000062
Terms relating to the winding impedance in equations (5) and (6) are expressed as equivalent impedance ZkThe equations (5) and (6) may be combined into the following form as the faulty phase voltage vector UCLExpression (c):
Figure BDA0001909264300000063
for single-phase disconnection fault, the voltage analysis process of the load side is basically consistent with that of single-phase grounding fault, and only the input voltage U of the C phase is influenced by disconnectionICBecomes 0. Therefore, the primary side voltage value U of the C phase (i.e. fault phase) of the load side transformer can be obtained by slightly modifying the formula (7)CLExpression:
Figure BDA0001909264300000064
for a single-phase ground fault, assume a C-phase (i.e., faulted phase) input voltage UICEqual to the C-phase voltage of the power supply side and expressed based on the formula (7)
Figure BDA0001909264300000071
Is UkThen U iskVector always AND (U)IA+UIB) The vector directions are the same. From this, a negative result can be obtained as shown in FIG. 4Vector diagram of voltage on the load side.
And for single-phase disconnection fault, the input voltage U of the C phaseICBecomes 0. Based on equation (8), vector diagram analysis is performed on the load side of the single-phase disconnection fault, as shown in fig. 5.
Comparing fig. 4 and 5, it can be seen that, for a single-phase earth fault, the voltage U measured in the C-phase after the faultCLIs UICAnd UkVector sum of (i.e., U) and its vector directionCLPhase of) and UICAnd UkIs directly related to the phase of the amplitude of (c). Therefore, the load-side fault phase voltage U of the single-phase ground fault varies with the system parameters and the fault occurrence conditionsCLBoth the phase and amplitude of (a) can vary significantly. For single-phase line-break faults, regardless of the parameter Z in equation (8)KAnd R0How to change load side voltage U of single-phase line break faultCLVector always AND (U)IA+UIB) The vector directions are the same. Therefore, system parameters and fault occurrence conditions have substantially no effect on this phase relationship. That is to say, it is a feasible and effective idea to identify the single-phase disconnection fault by using the relationship between the three-phase phases of the load-side voltage.
Through the contrastive analysis to the fault voltage characteristic, can obtain and utilize behind the trouble load side transformer voltage to carry out a basic thinking that single-phase broken string trouble and single-phase earth fault's fault discernment: assuming that the C phase is a fault phase, and simultaneously measuring a three-phase voltage vector U of the load side transformer through a distributed measuring deviceAL、UBLAnd UCLCalculating the sum (U) of vectors of two phases of three phases which are not failedAL+UBL) And fault phase vector UCLThe angle between them is theta, and a threshold value theta is setk. When theta is<θkAnd if not, determining that the fault is a single-phase disconnection fault.
Theoretically, the included angle theta of the single-phase disconnection fault is always equal to zero, so that the threshold theta can be determined only by analyzing the included angle theta of the single-phase grounding faultkA reasonable value of (c). Suppose that the line-to-ground distributed capacitance C is 4 x 10-7(F) Total conductance Y K2 × j ω C, equivalent impedance ZkThe included angle theta of the matlab software to the single-phase earth fault is along with the earth transition resistance R (500 omega)0(in log)10(R0) Formal representation) are calculated.
In particular, in matlab software at different R0Value (0)<R0<10000) Under the condition, according to the formula (4), the system neutral point voltage U is calculatedNOThen according to formula UAL＝EA+UNOAnd UBL＝EB+UNOCalculating the vector (U)AL+UBL) Coordinate (x) of1,y1) Then, U is calculated according to the above formula (7)CLFinally, the included angle value θ is calculated according to the following equation (9) based on the vector coordinates (x2, y 2).
Figure BDA0001909264300000072
Wherein x is1The abscissa which is the sum of the voltage vectors of the two phases in fault; x is the number of2The abscissa of the voltage vector of the fault phase; y is1The ordinate of the sum of the voltage vectors of the two phases in which the fault occurred; y is2The ordinate of the voltage vector of the faulted phase.
Will be different from R0Value (0)<R0<10000) The value of included angle theta under the condition is along with the transition resistance R of the grounding0(in log)10(R0) Formal representation) were plotted, and the results are shown in fig. 6.
As can be seen from fig. 6, for a general distribution network, after a single-phase earth fault occurs, the vector (U) isAL+UBL) And UCLIs always greater than 10 deg. and has a transition resistance R with the earth connection0Is increased with an increase in; and the included angle theta is always equal to zero after the single-phase disconnection fault occurs. Considering the influence of measurement error and other factors, the threshold value theta is setkSet at 8 ° to increase the accuracy of discrimination.
Therefore, based on the analysis, the invention provides a power distribution network single-phase disconnection fault identification method based on distributed measurement, which identifies single-phase disconnection faults based on the relation between three-phase phases of voltage on a load side.
The above method generally comprises the steps of:
step S1: a wide area measurement system is adopted to keep on-line monitoring on the power distribution network;
step S2: when the fault is detected, judging whether the fault is any one of single-phase earth fault or single-phase disconnection fault, if so, entering the following step S3, otherwise, ending the fault identification;
step S3: synchronously acquiring three-phase voltage data of one end of a fault point far away from a bus at the moment of the fault t by using a distributed measuring device in a wide area measuring system, and storing the acquired three-phase voltage data;
step S4: calculating an included angle value theta between the sum of the voltage vectors of two phases which do not have faults and the voltage vector of the fault phase by using the stored three-phase voltage data; and
step S5: and identifying whether the fault is a single-phase line break fault or not based on the included angle value theta.
In step S2, when a fault is detected, the voltage and current data collected by the wide-area measurement system are used to perform section location on the fault according to the D-type traveling wave location method, and then the positive sequence, negative sequence, zero sequence voltage and current data are obtained by using the symmetric component method, and whether the fault is a single-phase ground fault or a single-phase disconnection fault is determined according to the boundary condition of the single-phase ground fault and the single-phase disconnection fault.
In step S3, the voltage vectors of the three phases of the load-side transformer are measured simultaneously by the distributed measurement device.
In step S4, the coordinates (x) based on the sum of the voltage vectors of two of the three phases in which no failure has occurred are calculated1,y1) And coordinates (x2, y2) of the voltage vectors of the failed phase, and calculating an angle value theta between the sum of the voltage vectors of two phases which are not failed and the voltage vector of the failed phase in the three phases by the following formula (9):
Figure BDA0001909264300000081
wherein x is1Abscissa of sum of voltage vectors for two phases without fault, x2Abscissa, y, of the voltage vector of the faulted phase1Ordinate, y, of the sum of the voltage vectors of the two phases which have not failed2The ordinate of the voltage vector of the faulted phase.
In the above method, the voltage vector coordinate value of the a-phase before failure (i.e., one of the two phases that have not failed) is first defined as (0,1), and a coordinate system is established with the straight line as the y-axis and the vertical y-axis as the x-axis, and all the following vector calculations are calculated according to this coordinate system. According to formula UAL＝EA+UNOAnd UBL＝EB+UNOThe sum of the voltage vectors of the two phases that are not faulty is calculated and converted into the coordinates (x) in the above-mentioned coordinate system1,y1) Wherein U isNOIs the system neutral point voltage, UALIs the voltage vector of one of the two phases which has not failed, EAIs the pre-fault upstream voltage, U, of said one of the two phases that has not failedBLIs the voltage vector of the other of the two phases which has not failed, EBIs the pre-fault system supply side voltage of the other of the two phases that is not faulty.
In the above method, the voltage vector of the failed phase is calculated according to the following equation (7) and converted into coordinates (x) in the above-described established coordinate system2,y2)：
Figure BDA0001909264300000091
Wherein, UCLIs the voltage vector of the faulted phase, R0To ground transition resistance, ZKIs an equivalent impedance, UIAAnd UIBInput voltage, U, of a two-phase line-to-transformer without faultICIs the input voltage of the faulted phase line to the transformer.
In step S4, a line is assumedRoad-to-ground distributed capacitance C-4 x 10-7(F) Total conductance Y K2 × j ω C, equivalent impedance Zk500(Ω), at different R0Value (0)<R0<10000) Under the condition, the system neutral point voltage U is calculated by the following formula (4)NO：
Figure BDA0001909264300000092
Wherein E isCIs the voltage on the power supply side of the system before fault, Y, of any of the three phasesKIs the ground to ground conductance on the right side of the system in parallel with the line to ground distributed capacitance of any one of the three phases, C is the line to ground distributed capacitance of any one of the three phases, R0Is a ground transition resistance.
In step S4, the matlab software is also used to log the included angle value theta10(R0) Formal ground transition resistance R0Is calculated. Preferably, different R's are used0Value (0)<R0<10000) Angle of inclusion value theta under the condition is along with log10(R0) Formal ground transition resistance R0Is plotted to show the variation
Preferably, in step S5, when theta ≧ threshold thetakWhen the fault is a single-phase earth fault, when theta is<Threshold value thetakAnd if so, determining that the single-phase disconnection fault occurs.
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, the threshold value θ iskIs 10 deg..
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, the threshold value θ iskIs 8 deg..
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, when the included angle value theta is always greater than 10 degrees and follows log10(R0) Formal ground transition resistance R0When the voltage is increased, it is determined that a single-phase ground fault has occurred.
Preferably, in the method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement, when the included angle value θ is always equal to zero, the single-phase disconnection fault is determined to occur.
Examples
PSCAD/EMTDC software is used for establishing a simulation model of a single-loop power distribution network line, the rated voltage of the line is 10kV, and a topological graph of the single-loop power distribution network line is shown in FIG. 7. Several groups of faults are arranged at different positions in the distribution network line of the fig. 7, and each group of faults comprises single-phase disconnection faults and single-phase grounding faults. The set fault locations are located at lines 5-6, lines 2-3 and lines 12-13 in fig. 7, respectively, and the voltage at the primary side of the transformer downstream of the fault after the fault occurs is measured.
In the three sets of faults of lines 5-6, lines 2-3 and lines 12-13, the measured downstream transformer number is E, D, J respectively. By varying the ground transition resistance R0(0<R0<50000) Simulation measurement is carried out (for convenience of drawing comparison, grounding transition resistance R of a single-phase disconnection fault power supply side and a load side is assumed1And R2Are equal to each other, and are represented by R0Represented) for each different R0Recording the theta values measured and calculated according to said method and using log10(R0) Formally represented R0Drawing an included angle value theta along with R for a horizontal coordinate and theta for a vertical coordinate0The graphs of the changes are shown in fig. 8(a) to 8 (c).
In FIG. 8, it can be seen that three sets of fault angles θ follow R0Common features of the changes: the included angle value theta of the single-phase line break fault hardly follows R0Changing to always keep near 0 degrees; and the included angle value theta and R of the single-phase earth fault0Substantially in positive correlation with R0The increasing trend is gradually gradual. Two fault included angles theta along with R obtained through simulation0The variation trend of the method is basically consistent with the result obtained by theoretical calculation.
As can be seen from the figure, the resistance at ground is large (log)10(R0)>2, i.e. R0>100 omega), the included angle theta of the single-phase disconnection fault is always smaller than the theoretical threshold theta of 8 degreeskAnd single-phase wire-break fault clampThe angle theta is always greater than 8 deg.. Therefore, by comparing the included angle value theta with the theoretical threshold value thetakThe two faults can be accurately identified.
While the best mode for carrying out the invention has been described in detail and illustrated in the accompanying drawings, it is to be understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the invention should be determined by the appended claims and any changes or modifications which fall within the true spirit and scope of the invention should be construed as broadly described herein.

Claims (16)

1. A distribution network single-phase disconnection fault identification method based on distributed measurement is characterized by comprising the following steps:
the method for identifying the single-phase disconnection fault of the power distribution network based on distributed measurement comprises the following steps:
step S1: a wide area measurement system is adopted to keep on-line monitoring on the power distribution network;
step S2: when the fault is detected, judging whether the fault is any one of single-phase earth fault or single-phase disconnection fault, if so, entering the following step S3, otherwise, ending the fault identification;
step S3: synchronously acquiring three-phase voltage data of one end of a fault point far away from a bus at the moment of the fault t by using a distributed measuring device in a wide area measuring system, and storing the acquired three-phase voltage data;
step S4: calculating an included angle value theta between the sum of the voltage vectors of two phases which do not have faults and the voltage vector of the fault phase by using the stored three-phase voltage data;
step S5: identifying whether the fault is a single-phase wire break fault based on the included angle value θ.
2. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 1, wherein:
in step S2, when a fault is detected, the voltage and current data collected by the wide area measurement system are used to perform section location on the fault according to a D-type traveling wave location method, and then the positive sequence, negative sequence, zero sequence voltage and current data are obtained by using a symmetric component method, and whether the fault is a single-phase ground fault or a single-phase disconnection fault is determined according to the boundary conditions of the single-phase ground fault and the single-phase disconnection fault.
3. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 2, wherein:
the boundary conditions of the single-phase earth fault and the single-phase disconnection fault are as follows: the zero sequence current after the fault is not zero, and the positive sequence current and the negative sequence current after the fault are both smaller than the current before the fault.
4. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 1, wherein:
in step S3, the voltage vectors of the three phases of the load-side transformer are measured simultaneously by the distributed measurement device.
5. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 4, wherein:
in step S4, an angle value θ between the sum of the voltage vectors of two of the three phases that have not failed and the voltage vector of the failed phase is calculated by the following equation:
Figure FDA0002682343640000011
wherein x is1Abscissa of sum of voltage vectors for two phases without fault, x2Abscissa, y, of the voltage vector of the faulted phase1Ordinate, y, of the sum of the voltage vectors of the two phases which have not failed2The ordinate of the voltage vector of the faulted phase.
6. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 5, wherein:
defining the coordinate value of a voltage vector of one of two phases which do not have faults before the faults as (0,1), taking the straight line as a y axis and the vertical y axis as an x axis, establishing a coordinate system, and calculating all the following vector calculations according to the coordinate system and the formula UAL＝EA+UNOAnd UBL＝EB+UNOThe sum of the voltage vectors of the two phases that are not faulty is calculated and converted into coordinates (x) in the established coordinate system1,y1) Wherein U isNOIs the system neutral point voltage, UALIs the voltage vector of one of the two phases which has not failed, EAIs the pre-fault upstream voltage, U, of said one of the two phases that has not failedBLIs the voltage vector of the other of the two phases which has not failed, EBIs the pre-fault system supply side voltage of the other of the two phases that is not faulty;
the voltage vector of the faulted phase is calculated according to the following formula and converted into coordinates (x) in the established coordinate system2,y2)：
Figure FDA0002682343640000021
Wherein, UCLIs the voltage vector of the faulted phase, R0To ground transition resistance, ZKIs an equivalent impedance, UIAAnd UIBInput voltage, U, of a two-phase line-to-transformer without faultICIs the input voltage of the faulted phase line to the transformer.
7. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 6, wherein:
in step S4, the ground transition resistance R is varied0Under the condition of value, the system neutral point voltage U is calculated according to the following formulaNO：
Figure FDA0002682343640000022
Wherein E isCIs the voltage on the power supply side of the system before fault, Y, of any of the three phasesKIs the total conductance of the three-phase system, C is the line-to-ground distributed capacitance of any one of the three phases, R0Is a grounding transition resistor; wherein 0 omega<R0<10000Ω。
8. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 6 or 7, wherein:
for Y-Y transformers, ZK2Z, where Z is the resistance of any of the three phase windings.
9. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 6 or 7, wherein:
for delta-Y transformers, ZK(2/3) Z, where Z is the resistance of any of the three phase windings.
10. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 7, wherein:
in step S4, the matlab software is also used to log the included angle value theta10(R0) Formal ground transition resistance R0Is calculated.
11. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 7, wherein:
will be 0 omega<R0<Different R in 10000 omega range0Value of included angle theta with log10(R0) Formal ground transition resistance R0The change of (a) is plotted to show the change.
12. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 1, wherein:
in step S5, when theta is larger than or equal to the threshold thetakJudging the single-phase earth fault; when theta is<Threshold value thetakAnd if so, determining that the single-phase disconnection fault occurs.
13. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 12, wherein:
the threshold value thetakIs 10 deg..
14. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement as claimed in claim 12, wherein:
the threshold value thetakIs 8 deg..
15. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement according to claim 10 or 11, wherein the method comprises the following steps:
when the value of the included angle theta is always greater than 10 DEG and follows log10(R0) Formal ground transition resistance R0When the voltage is increased, it is determined that a single-phase ground fault has occurred.
16. The method for identifying the single-phase disconnection fault of the power distribution network based on the distributed measurement according to claim 10 or 11, wherein the method comprises the following steps:
and when the included angle value theta is always equal to zero, judging that the single-phase wire break fault occurs.
CN201811545634.XA 2018-12-18 2018-12-18 Distribution network single-phase line break fault identification method based on distributed measurement Active CN109324269B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811545634.XA CN109324269B (en) 2018-12-18 2018-12-18 Distribution network single-phase line break fault identification method based on distributed measurement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811545634.XA CN109324269B (en) 2018-12-18 2018-12-18 Distribution network single-phase line break fault identification method based on distributed measurement

Publications (2)

Publication Number Publication Date
CN109324269A CN109324269A (en) 2019-02-12
CN109324269B true CN109324269B (en) 2021-02-19

Family

ID=65256229

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811545634.XA Active CN109324269B (en) 2018-12-18 2018-12-18 Distribution network single-phase line break fault identification method based on distributed measurement

Country Status (1)

Country Link
CN (1) CN109324269B (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109917227A (en) * 2019-03-26 2019-06-21 上海交通大学 Power distribution network single-phase disconnection fault identification method based on phase relation
US11143715B2 (en) * 2019-08-15 2021-10-12 Schweitzer Engineering Laboratories, Inc. Broken conductor detection in a multiple-phase electric power delivery system
CN111007355A (en) * 2019-12-11 2020-04-14 苏州银蕨电力科技有限公司 Disconnection fault detection method based on wide-area synchronous intelligent sensor
CN110912161B (en) * 2019-12-12 2023-05-12 西南交通大学 Method for discriminating incoming line phase failure of traction substation power supply
CN111244913B (en) * 2020-02-21 2020-09-25 贵州电网有限责任公司 Power distribution network single-phase disconnection fault protection method considering neutral point grounding mode influence
CN112946374B (en) * 2021-01-27 2024-03-19 华北电力大学 Three-phase unbalance detection method and device based on convolution window function
CN113203915B (en) * 2021-04-16 2022-10-28 国网宁夏电力有限公司电力科学研究院 Multi-source information fusion power distribution network single-phase line fault analysis method
CN113325333A (en) * 2021-05-14 2021-08-31 青岛鼎信通讯股份有限公司 Small current grounding system disconnection detection method suitable for fault indicator
CN113422356B (en) * 2021-07-08 2022-07-22 国网河北省电力有限公司电力科学研究院 Active power distribution network disconnection fault protection method and device and power distribution terminal

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101452041B (en) * 2008-12-26 2010-10-20 湖北省电力试验研究院 Electrical power distribution network single-phase earth fault type and phase distinguishing method
US8937822B2 (en) * 2011-05-08 2015-01-20 Paul Wilkinson Dent Solar energy conversion and utilization system
CN102636731B (en) * 2012-04-12 2015-05-20 上海交通大学 Power distribution network single-phase disconnection judging and addressing method based on load measuring and recording system
CN204462305U (en) * 2015-03-16 2015-07-08 王金泽 A kind of distribution line disconnection monitor based on electric current and voltage vector
CN104730410B (en) * 2015-03-16 2017-11-21 王金泽 A kind of distribution line disconnection monitoring method and device based on voltage x current vector
CN104777397B (en) * 2015-04-16 2017-09-22 王金泽 Distribution line single-phase wire break based on the vectorial criterion of line voltage judges and localization method
CN107340455B (en) * 2016-04-28 2023-10-24 王金泽 Single-phase broken line fault identification method and application of high-voltage circuit of power distribution network
CN106872852B (en) * 2017-01-13 2019-04-23 济南大学 Power distribution network single-phase disconnection based on residual voltage is grounded multiple fault type diagnostic method

Also Published As

Publication number Publication date
CN109324269A (en) 2019-02-12

Similar Documents

Publication Publication Date Title
CN109324269B (en) Distribution network single-phase line break fault identification method based on distributed measurement
Das et al. Transmission line fault detection and location using wide area measurements
CN109283430B (en) Power distribution network fault location method based on voltage distribution principle
Lee et al. Multi-terminal nonhomogeneous transmission line fault location utilizing synchronized data
CN109523165B (en) Voltage sag state estimation method based on limited information
CN109283429A (en) A kind of Fault Location for Distribution Network method based on positive-negative sequence impedance principle
CN111551824A (en) Phase voltage amplitude and phase angle change rate ground fault phase selection method and device considering three-phase asymmetry
CN109444666B (en) Power distribution network single-phase high-blocking line fault identification method and device
CN108845225B (en) Method for analyzing wiring correctness of secondary current loop of power capacitor and reactor
CN111551822B (en) Power distribution network single-phase earth fault phase selection method and device
Amberg et al. Validating transmission line impedances using known event data
CN111983510B (en) Single-phase ground fault phase selection method and system based on phase voltage and current abrupt change
CN107037324B (en) Fault location method free from transition resistance based on single-end electric quantity
CN105914718A (en) Phase current sudden change based earth fault protection method
Liu et al. Identification method for single-line-to-ground faults with line break based on phasor measurement in distribution networks
Penido et al. An analytical zero sequence method to locate fault in distribution systems rich in DG
de Pereira et al. Fault location in multitapped transmission lines using unsynchronized data and superposition theorem
WO2020191825A1 (en) Phase-relationship-based method for single-phase disconnection fault identification in power distribution network
Qin et al. Single-phase disconnection fault location method based on negative sequence current distribution feature
Fang et al. A Data‐Driven Fault Location Method in Distribution Network Based on PMU Data
Ramar et al. New fault location algorithms for transmission lines in interconnected power systems
Bao-Wei et al. Two-terminal fault location scheme based on distributed parameters of cable-overhead hybrid transmission line
CN104777404B (en) Based on differential energy than distribution line fault section location method
Xu et al. Faulty line selection based on active-intervention-type arc suppression device via additional neutral resistance
CN115308536B (en) Mu PMU-based DG-containing power distribution network fault section identification method

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