System and method for determining distance to fault in hybrid line system
By calculating voltage and current phasors in a hybrid line system, and utilizing the ABCD parameter network model and the Newton-Raphson method, the problem of inaccurate fault location in the hybrid line system is solved, achieving fault location with high accuracy and low error rate.
Patent Information
- Application Number
- CN202480033123.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-03-22
- Filing Date
- 2024-03-01
- Publication Date
- 2026-02-27
AI Technical Summary
Existing technologies struggle to accurately calculate the distance to faults in hybrid line systems, especially in systems involving multiple sections, underground cables, and overhead lines exceeding 100 kilometers in length. In particular, the location of single-phase grounding or phase-to-phase faults with high fault resistance is inaccurate, and the derivative of the fault location function cannot be analyzed and expressed.
By calculating voltage and current phasors, using a network model with ABCD parameters, and combining the Newton-Raphson method, fault sections are identified and the distance to the fault is calculated. Single-ended measurement and distributed parameter methods are used, combined with discrimination criteria and phasor comparison, to improve the accuracy of location.
It achieves improved fault location accuracy with an error rate of less than 2% under high fault resistance conditions, and can identify faulty sections and calculate the distance to the fault.
Smart Images
Figure CN121586846A_ABST
Abstract
Description
[0001] Cross-references to related applications This application claims the benefit of U.S. Application No. 18 / 188237, filed March 22, 2023, the entire contents of which are hereby incorporated by reference. Technical Field
[0002] This application and the resulting patents generally relate to hybrid line systems, and more specifically to systems and methods for determining the distance to a fault in a hybrid line system. Background Technology
[0003] Generally speaking, fault location in cable and / or hybrid line systems differs from fault location in transmission lines. This difference is partly due to the importance of the parallel capacitance of the cables. It is also partly due to the nonlinear nature of the line impedance (or other line parameters) relative to the line length caused by the distributed parameters along the line and / or cable.
[0004] Therefore, there is a growing need for a method to accurately calculate the distance to a fault in certain types of systems (e.g., systems involving mixed lines, line systems with multiple sections, systems involving underground cables, and / or systems involving overhead lines exceeding 100 km in length) based on single-ended measurements. This can be achieved by applying a network with distributed ABCD parameters (i.e., ABCD transmission parameters composed of distributed primary parameters of the line or cable). If the fault is a single-phase-to-ground fault with a higher fault resistance, a zero-sequence network with distributed ABCD parameters can be used to locate the fault. If the fault is a phase-to-phase fault with a higher fault resistance, a negative-sequence network with distributed ABCD parameters can be used to locate the fault. The benefits of using distributed ABCD parameters include increased accuracy in area location and distance location to the fault using single-ended measurements, with an error rate of less than 2% for single-phase-to-ground faults and phase-to-ground (including three-phase) faults with a resistance of 20 ohms and a source impedance ratio (SIR) of 10.
[0005] Even with increased fault resistance, fault location remains accurate. This is partly due to the fault location analysis considering the types of faults present, where separate fault location algorithms can be implemented for single-phase-to-ground faults and phase-to-ground (including three-phase) faults. It is also partly due to the use of the Newton-Raphson method for fault location calculation, as the derivative of the fault location function cannot be analytically expressed. Furthermore, the fault segment detection process employs a discrimination criterion that compares the calculated virtual phasor with the local phasor used for each segment. Summary of the Invention
[0006] Therefore, this application and the resulting patents provide a method for determining the distance to a fault in a hybrid line system. The method may include the following steps: calculating a first set of voltage phasors and a first set of current phasors based at least in part on a set of measured voltage samples and a set of measured current samples; calculating ABCD parameters associated with the hybrid line system based at least in part on input line parameters associated with the hybrid line system; calculating a second set of voltage phasors and a second set of current phasors based at least in part on the first set of voltage phasors, the first set of current phasors, and the ABCD parameters; collecting faulty phase voltage phasors and faulty phase current phasors based at least in part on the second set of voltage phasors and the second set of current phasors; identifying faults in faulty sections of the hybrid line system and parameters associated with those faults based at least in part on the faulty phase voltage phasors and faulty phase current phasors; and calculating the distance to the fault based at least in part on the parameters associated with the fault.
[0007] This application and the resulting patent also provide a method for determining the distance to a fault in a hybrid line system. The method may include the following steps: receiving a set of measured voltage samples and a set of measured current samples at a first bus of the hybrid line system; calculating a first set of voltage phasors and a first set of current phasors based at least in part on the set of measured voltage samples and the set of measured current samples; receiving input line parameters associated with the hybrid line system; calculating ABCD parameters associated with the hybrid line system based at least in part on the input line parameters; calculating a second set of voltage phasors and a second set of current phasors at a second bus of the hybrid line system based at least in part on the first set of voltage phasors, the first set of current phasors, and the ABCD parameters; collecting faulty phase voltage phasors and faulty phase current phasors based at least in part on the second set of voltage phasors and the second set of current phasors; identifying a fault in a faulty section of the hybrid line system and parameters associated with the fault based at least in part on the faulty phase voltage phasors and faulty phase current phasors; and calculating the distance to the fault point based at least in part on the parameters associated with the fault.
[0008] This application and the resulting patents also provide a hybrid line system. The hybrid line system may include a first segment having a first busbar and a second segment having a second busbar, wherein a first set of voltage phasors and a first set of current phasors are calculated based at least in part on a set of measured voltage samples and a set of measured current samples associated with the first segment; wherein ABCD parameters associated with the hybrid line system are calculated based at least in part on input line parameters associated with the hybrid line system; wherein a second set of voltage phasors and a second set of current phasors associated with the second segment are calculated based at least in part on the first set of voltage phasors, the first set of current phasors, and the ABCD parameters; wherein faulty phase voltage phasors and faulty phase current phasors are collected based at least in part on the second set of voltage phasors and the second set of current phasors; and wherein faults in faulty segments of the hybrid line system and parameters associated with those faults are identified based at least in part on the faulty phase voltage phasors and faulty phase current phasors.
[0009] These and other features and improvements of this application and the resulting patents will become apparent to those skilled in the art when examined in conjunction with the following detailed description, which is taken in conjunction with the accompanying drawings and the appended claims. Attached Figure Description
[0010] Figure 1 This is a schematic diagram of an algorithm for calculating the distance to a fault based on ABCD parameters according to one or more example embodiments of this disclosure.
[0011] Figure 2 This is a schematic diagram of a hybrid circuit system according to one or more exemplary embodiments of the present disclosure.
[0012] Figure 3A It is based on Figure 1 A schematic diagram of the algorithm for performing phasor calculations.
[0013] Figure 3B It is based on Figure 1 A schematic diagram of the algorithm for performing phasor calculations.
[0014] Figure 4 It is based on Figure 1 A schematic diagram of the algorithm that performs phasor calculations at the next bus based on ABCD parameters.
[0015] Figure 5 It is based on Figure 1 A schematic diagram of an algorithm for collecting faulty phasors.
[0016] Figure 6A It is based on Figure 1 A schematic diagram of the algorithm for identifying faulty sections.
[0017] Figure 6B It is based on Figure 1 A schematic diagram of the algorithm for identifying faulty sections.
[0018] Figure 7 It is based on Figure 1 The algorithm describes a flowchart for calculating the distance to the fault. Detailed Implementation
[0019] Referring now to the accompanying drawings, where similar numbers throughout several views represent similar elements. Figure 1 This is a schematic diagram 100 illustrating the calculation of the distance to a fault based on ABCD parameters. This diagram 100 is applicable to fault distance calculation for multi-section mixed overhead lines or cables. At box 102, voltage and current phasors can be calculated by applying a Fourier transform with attenuated DC removed components to single-ended voltage and current samples. This process can be performed within... Figure 3A Further details are provided in section -B. At box 104, the positive-sequence and zero-sequence ABCD parameters for the corresponding segment can be calculated based on the line parameters for each segment of the hybrid line system. The line parameters may include the positive-sequence and zero-sequence series impedances and shunt admittances per length for each corresponding segment. The line parameters can be input by the user. This process is available in... Figure 4 Further details are provided in the text.
[0020] At box 106, the voltage and current phasors of the next bus can be calculated based on the voltage and current phasors from one terminal bus calculated at box 102 and the ABCD parameters calculated at box 104. Furthermore, the negative-sequence and zero-sequence source impedances of each bus can be calculated. At box 108, the faulty phase voltage and current phasors, along with the corresponding parameters for the faulty phase voltage and current phasors, can be collected. This process can be performed within... Figure 5 Further details are provided below. At box 110, a faulty segment can be identified by comparing the calculated faulty phase voltage phasors with each other, or by comparing the calculated faulty phase voltage phasors with the zero-sequence current of the corresponding segment. Once the faulty segment is identified, the corresponding voltage and current phasors, along with the corresponding parameters, can be collected. This process can be performed within... Figure 6A Further details are provided in section -B. At box 112, the distance to the fault is calculated based on the identified faulty phase voltage and current phasors using an ABCD-based fault location algorithm. This process can be performed within... Figure 7 Further details are provided in the text.
[0021] Figure 2 This is a schematic diagram of a hybrid circuit system, number 200. Figure 2 As described, a hybrid circuit system may have N-1 sections. Therefore, section 1 (S1) may be associated with a specific voltage. US1 and current I S1 Related. Section 2 (S2) may be associated with a specific voltage. U S2 and current I S2 Associated. Each subsequent segment may be associated with a specific voltage U. Sk and current I Sk Associated, where k represents the k-th segment. The last segment (SN-1) may be associated with a specific voltage. U SN- 1 and current I SN-1 Related. The final section (SN-1) may end at bus SN, which may be associated with a specific voltage. U SN Related.
[0022] Figure 3A It is based on Figure 1 The schematic diagram 300A illustrates the algorithm for performing phasor calculations. This algorithm for performing phasor calculations can be applied to... Figure 1 Box 102 in the diagram. The algorithm performs phasor calculations by performing a Fourier transform with attenuated DC cancellation. At the local end, samples of each phase voltage and phase current can be measured. These samples may include: three-phase voltages, such as... u a ( n 302A u a ( n ) 302B and u c ( n ) 302C; and three-phase current, such as i a ( n 304A i b ( n )304B and i c ( n ) 304C. Three-phase voltages 302A-C and 304A-C can be inputs to this algorithm. After a Fourier transform with attenuated DC removal components, where u a ( n 302A u a ( n 302B u c ( n 302C ia ( n 304A i b ( n 304B and i c ( n 304C is the corresponding input, and the algorithm can output the corresponding values. U a ( n 306A U b ( n 306B U c ( n 302C I a ( n 308A I b ( n ) 308B and I c ( n 308C. Output U a ( n 306A U b ( n ) 306B and U c ( n )302C can represent a set of voltage phasors, while the output I a ( n 308A I b ( n ) 308B and I c ( n 308C can represent a set of current phasors.
[0023] Figure 3B It is based on Figure 1 Another schematic diagram 300B illustrates the algorithm depicted in the diagram performing phasor calculations. More specifically, Figure 3B The process of performing a Fourier transform with attenuated DC removal components is described. First, the input... x ( n )(For example, u a ( n )302A、 u a ( n 302B uc ( n 302C i a ( n 304A i b ( n 304B or i c ( n (304C) can be applied to cosine filters (COS). F ( n 310. The coefficients of the cosine filter 310 can be as follows: Where N represents the number of samples per period. Then, the output of the cosine filter 310 can be as follows: The output of the cosine filter 310 can be used to determine the real component 312 and the imaginary component 314 of the phasor. The real component 312 can be determined as follows: Therefore, the real component 312 can be partially based on the application of the output of the cosine filter 310. z -1 The function determines this. The imaginary component 314 can be determined as follows: Therefore, the imaginary component 314 can be partially based on the application of the output of the cosine filter 310. z- 2 The function determines this. Then, the phasor output component 316 can receive the real component 312 ( RealX ( n )) and imaginary component 314 ( ImagX ( n and output phasors This phasor PhasorX(n) It can represent voltage phasors and / or current phasors.
[0024] therefore, Figure 3B The algorithm described in the paper can be used to output Figure 3A The voltage phasor described in U a ( n 306A U b ( n ) 306B and U c ( n 302C, and current phasorsI a ( n 308A I b ( n ) 308B and I c ( n 308C.
[0025] Figure 4 This is a schematic diagram 400 illustrating an algorithm for performing phasor calculations at the next bus based on the ABCD parameters. To perform phasor calculations at the next bus based on the ABCD parameters, the ABCD parameters must first be calculated. This allows for the identification of each line segment. L Sk The length of the line, of which Sk It is the first k There are n line segments, and k = 1, 2, …, N-1. Each line segment... L Sk The line length can be input by the user. The positive-sequence and zero-sequence impedances and admittances for each length of each line segment can also be identified and input by the user. Lengths can be indicated in kilometers, meters, or miles. Positive-sequence impedance can be denoted as... The zero-sequence impedance can be written as Positive-order admittance can be denoted as And the zero-sequence admittance can be written as Compared to cables, the line section For overhead lines, the positive-sequence and zero-sequence admittances are... and No user input is required because of the positive and zero-order admittances. and It can be calculated as follows: as well as in f It is the system frequency, which may be 50 Hz or 60 Hz. c 1 = 2.95 x 10 5 km / s ,and c 1 Represents the positive-sequence traveling wave velocity, and c 0 = 2.8 x 10 5 km / s ,and c 0 This represents the zero-sequence traveling wave velocity.
[0026] After inputting and / or calculating each line segmentL Sk The line length and the positive-sequence and zero-sequence impedances and admittances per length z 1Sk z 0Sk y 1Sk and y 0Sk Then, the positive-order ABCD parameters and the zero-order ABCD parameters can be calculated. Positive-order ABCD parameters (which are...) A 1Sk , B 1Sk , C 1Sk and D 1Sk It can be calculated as follows: in as well as .
[0027] Zero-order ABCD parameters (where A is A) 0Sk B 0Sk C 0Sk and D 0Sk It can be calculated as follows: in as well as .
[0028] like Figure 4 The positive-sequence and zero-sequence ABCD parameters, voltage phasors (e.g., as described in the text) Figure 3A The description in U a ( n )306A、 U b ( n ) 306B and U c ( n ) 306C) and current phasors (e.g., such as Figure 3A The description in I a ( n 308A I b ( n )308B and I c ( n The 308C can be used as input to the ABCD algorithm component. The ABCD algorithm component can receive these inputs and apply the ABCD algorithm to calculate the voltage phasor and current phasor at the next bus.
[0029] To calculate the voltage and current phasors at the next bus, the ABCD algorithm component can execute the following ABCD algorithm: in as well as For example, the first ABCD algorithm component 402, the second ABCD algorithm component 404, the third ABCD algorithm component 406, and the fourth ABCD algorithm component 408 can apply the ABCD algorithm as described herein.
[0030] Therefore, the ABCD algorithm can be used to calculate the voltage and current phasors at the next bus in a hybrid line system. For example, referencing... Figure 2 A mixed line system may include: Section 1 ( S1 ), which has the following characteristics U S1 The three-phase voltage and for I S1 Three-phase current; Section 2 ( S2 ), which has the following characteristics U S2 The three-phase voltage and for I S2 Three-phase current; any number of subsequent sections; final section ( SN-1 ), which has the following characteristics U SN- 1 The three-phase voltage and for I SN-1 The three-phase current, with the last section at the busbar. SN The end is here, where the three-phase voltage is U SN Therefore, in S1 At this location, the first ABCD algorithm component 402 can receive voltage... U S1 The three corresponding voltage phasors ( U aS1 ( n ), U bS1 ( n )and U cS1 ( n )), and current I S1 The three corresponding current phasors ( I aS1 ( n ), I bS1 ( n )and I cS1 (n )) for S1 The ascending order ABCD parameters (ABCD 1S1 ) and the zero-sequence ABCD parameter (ABCD) for S1 0S1 The first ABCD algorithm component 402 can then apply the ABCD algorithm to calculate... S2 The three voltage phasors at ( U aS2 ( n ), U bS2 ( n )and U cS2 ( n ))as well as S2 The three current phasors at ( I aS2 ( n ), I bS2 ( n )and I cS2 ( n )).
[0031] Subsequently, S2 Voltage phasor at ( U aS2 ( n ), U bS2 ( n )and U cS2 ( n ))and S2 Current phasor at ( I aS2 ( n ), I bS2 ( n )and I cS2 ( n This can be used as input to the second ABCD algorithm component 404. The second ABCD algorithm component 404 can also receive... S2 The orthogonal ABCD parameter at position (ABCD) 1S2 )and S2 The zero-order ABCD parameter at the location (ABCD) 0S2 The input is taken as input. Then, the second ABCD algorithm component 404 can apply the ABCD algorithm to calculate the voltage phasors and current phasors at subsequent segments of the hybrid line system. This process can be repeated for as many segments as possible in the hybrid line system.
[0032] like Figure 4As described, the third ABCD algorithm component 406 is configured to receive data from the penultimate segment. SN-2 voltage phasors ( U aSN-2 ( n ), U bSN-2 ( n )and U cSN-2 ( n )) and current phasor ( I aSN-2 ( n ), I bSN-2 ( n )and I cSN-2 ( n The third ABCD algorithm component 406 also receives (as input). SN-2 The ascending ABCD parameters (ABCD1SN-2) at the position and SN-2 The zero-sequence ABCD parameters (ABCD0SN-2) at the specified location are used as input. Then, the third ABCD algorithm component can apply the ABCD algorithm to calculate the final segment of the hybrid line system. SN-1 Voltage phasor at ( U aSN-1 ( n ), U bSN-1 ( n )and U cSN-1 ( n )) and current phasor ( I aSN-1 ( n ), I bSN-1 ( n )and I cSN-1 ( n )).
[0033] In point SN To represent the end of the hybrid line system, the fourth ABCD algorithm component 408 is configured to receive data from the last segment. SN-1 voltage phasors ( U aSN - 1( n ), U bSN - 1( n )and U cSN - 1( n )) and current phasor ( I aSN - 1(n ), I bSN - 1( n )and I cSN - 1( n The fourth ABCD algorithm component 408 also receives the positive-order ABCD parameters at SN-1 as input. ABCD 1SN-1 ) and zero-order ABCD parameters ( ABCD 0SN-1 ) as input. Then, the fourth ABCD algorithm component 408 can apply the ABCD algorithm to calculate the voltage phasor at the last point SN of the hybrid line system ( U aSN ( n ), U bSN ( n )and U cSN ( n )) and current phasor ( I aSN ( n ), I bSN ( n )and I cSN ( n )).
[0034] Figure 5 A schematic diagram 500 depicts an algorithm for collecting faulty phasors. After calculating and / or collecting the voltage and current phasors at each bus of the hybrid line system, the faulty phase voltage and current phasors and their corresponding parameters can be collected via the external indication DDB_TF_PHS for faulty phase selection. The voltage and current phasors at the first bus are the voltage and current phasors measured at the beginning of the hybrid line system. The voltage and current phasors at subsequent buses use the ABCD algorithm (e.g., ...). Figure 4 The calculation is performed using the ABCD algorithm described in the diagram.
[0035] Therefore, the inputs to the faulty phasor collection component 502 may include DDB_FT_PHS (which is the faulty phase indicator) and each set of voltage and current phasors calculated and / or collected at each bus in the hybrid line system. For example, the inputs may include U aS1 , U bS1 , U cS1 , I aS1 , I bS1 andI cS1 They represent the first section of a hybrid line system (e.g., Figure 2 The voltage and current phasors of segment 1 (S1) in the circuit. Because these phasors represent the first segment of the hybrid line system, U aS1 , U bS1 , U cS1 , I aS1 , I bS1 and I cS1 It can be determined from the voltage and current phasors measured at the beginning of the hybrid circuit system. That is, U aS1 = U a , U bS1 = U b , U cS1 = U c , I aS1 = I a , I bS1 = I b ,as well as I cS1 = I c Other inputs may include a second section of the hybrid line system (e.g., Figure 2 The voltage and current phasors at section 2 (S2) in the middle, for example U aS2 , U bS2 , U cS2 , I aS2 , I bS2 and I cS2 Additional inputs can include voltage and current phasors at any subsequent segments of the hybrid line system. Another input can include voltage and current phasors at the final bus of the hybrid line system (i.e., at the end of the final segment of the hybrid line system). These voltage and current phasors can be used... U aSN , U bSN , U cSN, I aSN , I bSN and I cSN express.
[0036] Upon receiving input, the faulty phasor collection component 502 can apply the following principles to collect the faulty voltage and / or current phasors: If the fault indicated by DDB_FT_PHS is a phase-A ground fault, the following equation can be applied.
[0037] If the fault indicated by DDB_FT_PHS is a phase B ground fault, the following equation can be applied.
[0038] If the DDB_FT_PHS indicates a C-phase ground fault, the following equation can be applied.
[0039] If the fault indicated by DDB_FT_PHS is a phase A-phase B fault, a phase A-phase B-phase ground fault, a phase A-phase B-phase C fault, or a phase A-phase B-phase C-phase ground fault, then the following equation can be applied.
[0040] If the fault indicated by DDB_FT_PHS is a B-phase-C-phase fault or a B-phase-C-phase ground fault, the following equation can be applied.
[0041] If the fault indicated by DDB_FT_PHS is a C-phase-A phase fault or a C-phase-A phase ground fault, the following equation can be applied.
[0042] The faulty phasor collection component 502 can use the DDB_FT_PHS input and appropriate equations to determine the voltage and current phasors for each set received by the faulty phasor collection component. U RSk , I RSk , U 0NegSk and I 0NegSk For example, in response to receiving U aS1 , U bS1 , UcS1 , I aS1 , I bS1 and I cS1 A faulty phasor collection unit 502 can output... U RS1 , I RS1 , U 0NegS1 and I 0NegS1 Furthermore, in response to receiving U aS2 , U bS2 , U cS2 , I aS2 , I bS2 and I cS2 A faulty phasor collection unit 502 can output... U RS2 , I RS2 , U 0NegS2 and I 0NegS2 Additionally, in response to receiving U aSN , U bSN , U cSN , I aSN , I bSN and I cSN A faulty phasor collection unit 502 can output... U RSN , I RSN , U 0NegSN and I 0NegSN .
[0043] Figure 6A This is a schematic diagram 600A of an algorithm for identifying faulty sections (e.g., in a hybrid line system). The algorithm may include a source impedance calculation component 602 and a faulty section identification and parameter collection component 604. The source impedance calculation component 602 may receive at least one set of inputs. U 0NegSk , I 0NegSk , ABCD0Sk and ABCD 1Sk This involves receiving a set of inputs for each segment of the hybrid line system. For example, for a hybrid line system with N-1 segments, the source impedance calculation component 602 can receive... U 0NegS1 , I 0NegS1 , ABCD 0S1 and ABCD 1S1 , ... , U 0NegSN-1 , I 0NegSN-1 , ABCD 0SN-1 and ABCD 1SN-1 The source impedance calculation component 602 can also receive DDB_FT_PHS as input.
[0044] Source impedance calculation component 602 can use these inputs to calculate the following outputs: for each segment z SourceSkL Used for each section z SourceSkR and for each segment ABCD Sk In other words, in a hybrid line system there are N-1 In the case of a single segment, the source impedance calculation component 602 can output... z SourceS1L , ... , z SourceSN-1L , z SourceS1R , ... , z SourceSN-1R , ABCD S1 , ... , ABCD SN-1 The output can then be used as input to the faulty section identification and parameter collection component 604. Local and remote source impedances can be calculated as follows: If the faulty phase is indicated as a single-phase ground fault, then A Sk , B Sk , C Sk and D Sk These are the zero-sequence ABCD parameters of segment k; and if any faulty phase is indicated as a phase-to-phase fault, phase-to-ground fault, three-phase fault, or three-phase-to-ground fault, then... ASk , B Sk , C Sk and D Sk It is the ascending ABCD parameter of segment k.
[0045] Other inputs to the faulty section identification and parameter collection component 604 may include the following: for each section U RSk Used for each section I RSk and for each segment I 0NegSk For example, in a mixed line system with N-1 sections, where the N-1th section ends at bus SN, the faulty section identification and parameter collection component 604 can receive the following inputs: U RS1 , I RS1 , I 0NegS1 , ... , U RSN , I RSN and I 0NegSN These inputs can be obtained from faulty phasor collection components (e.g., Figure 5 The faulty phasor collection component 502 described in the figure outputs the faulty section identification and parameter collection component 604. Then, the faulty section identification and parameter collection component 604 can determine the faulty section in the hybrid line system.
[0046] exist Figure 6B Algorithm 600B for identifying faulty sections is described. Faulty section identification and parameter collection component 604 may include a faulty section identification component for each section in the hybrid line system. For example, faulty section identification and parameter collection component 604 may include a faulty S1 section identification component 606, ..., and a faulty SN-1 section identification component 608. The faulty section identification component for each section can receive... U RSk , U RSk + 1 , I 0NegSk And DDB_FT_PHS as input. For example, a faulty S1 segment identification component 606 can receive U RS1 , U RS2 , I 0NegS1And DDB_FT_PHS as input. The faulty SN-1 segment identification component 608 can receive... U RSN- 1 , U RSN , I 0NegSN-1 And DDB_FT_PHS as input.
[0047] In a hybrid line system, the faulty section identification component for each segment can be configured to generate an output DDB_FT_SECT_Sk, indicating whether the segment is faulty or not. For example, the faulty S1 segment identification component 606 can output DDB_FT_SECT_S1, determining whether S1 is faulty, and the faulty SN-1 segment identification component 608 can output DDB_FT_SEC_SN-1, determining whether SN-1 is faulty. To generate the output DDB_FT_SECT_Sk, each of the faulty section identification components (e.g., the faulty S1 segment identification component 606 and the faulty SN-1 segment identification component 608) can apply the following conditions. If the fault is a phase-to-phase fault, a phase-to-phase grounding fault, or a three-phase fault, the following conditions are applied: in U Sk It is the first k Voltage of each bus ， and U Sk + 1 Is the ( k + 1 The voltage of each busbar. If the fault is a single-phase ground fault, the following conditions apply: in U Sk + 1 Is the ( k + 1 The voltage of each busbar, I 0Sk It is the first k Zero-sequence current at each busbar, and Alpha It is the compensation angle, in which If the applicable conditions are met, the output DDB_FT_SECT_Sk can be set to 1.
[0048] Different DDB_FT_SECT_Sk outputs (where k = 1, 2, … , N-1) can be input to final logic component 610, which can be configured to determine faulty segments in the hybrid line system. Final logic component 610 can generate a table of DDB_FT_SECT_Sk values. Furthermore, if DDB_FT_SECT_Sk = 1 and DDB_FT_SECT_Sk-1 = 0, then final logic component 610 can determine that the k-th segment is faulty. Therefore, final logic component 610 can output DDB_FT_SECT, which identifies one or more faulty segments in the hybrid line system.
[0049] Return to Figure 6A After identifying one or more faulty sections, the faulty section identification and parameter collection component 604 can output the following for each faulty section: U R , I R , U 0Neg , I 0Neg , z SourceL , z SourceR L and DDB_FT_SECT. These outputs represent the identification of the faulty segment, the corresponding voltage, the corresponding current, and parameters associated with the faulty segment, which can be used to calculate the distance to the fault. If the k-th segment is identified as a faulty segment, the faulty segment identification and parameter collection component 604 can generate the following output parameters: U R = U RSk , I R = I RSk , U 0Neg = U 0NegSk , I 0Neg = I 0NegSk , ABCD = ABCD Sk , L = L Sk , z SourceL = z SourceSkL and z SourceR = z SourceSkROther outputs may include the positive and zero-order ABCD parameters associated with each faulty segment.
[0050] Then, the distance to the fault can be calculated using the output parameters by applying the following formula: If the indicated fault is a single-phase ground fault, the voltage at the fault point is calculated as follows: Fault current distribution coefficient C f ( x ) can be calculated as If the fault is indicated as a phase-to-phase fault, phase-to-ground fault, three-phase fault, or three-phase-to-ground fault, the voltage at the fault point can be calculated as follows: Fault current distribution coefficient C f ( x ) can be calculated as because G ( x ) is a nonlinear equation that can be solved using the Newton-Raphson method.
[0051] Figure 7 A flowchart 700 is depicted for calculating the distance to the fault. First, the voltage and current phasors of the fault segment, the length and ABCD parameters of the fault segment, the local and remote equivalent source impedances of the fault segment, and the fault phase information of the fault segment must be known. At box 702, it can be determined whether the fault is a single-phase-to-ground (SLG) fault. If the fault is a single-phase-to-ground (SLG) fault, then at box 704A, x initial value x 0 It can be set to half the line length. At box 706A, in the case of a single-wire ground fault, V F ( x )and C f ( x It can be calculated as follows: At box 708A, the calculation can be performed for... G ( x 0 The function of ). It can perform calculations.
[0052] At box 710A x The value can be obtained from x 0 Increment to x 1 ,in x 1 = x 0 + dx And can be calculated for G ( x 1 The function of ). Calculations can be performed. Calculations can be performed at box 712A. G ( x Relative to x The derivative of . That is Calculations can be performed. At box 714A, the first correction value can be calculated. And can be determined G ( x Latest The value of ), where At box 716A, G ( x Latest The value of ) is compared with a predetermined threshold. If G ( x Latest If the value of ) is less than the predetermined threshold, then the distance to the fault is . x Latest .if G ( x Latest If the value of ) is not less than the predetermined threshold, then x 0 reset to x Latest And the process restarts from box 706A.
[0053] If the fault is not a single-wire ground fault (SLG), then at box 704B, x initial value x 0 It can be set to half the line length. At box 706B, it can be calculated based on the equation described herein. V F ( x )and C f ( x ).
[0054] At box 708B, the calculation can be performed for... G (x 0 The function of ). Calculations can be performed. At box 710B, x The value can be obtained from x 0 Increment to x 1 ,in x 1 = x 0 +dx And can be calculated for G ( x 1 The function of ). Calculations can be performed. Calculations can be performed at box 712B. G ( x Relative to x The derivative of . That is, it can be calculated. G’ ( x ) = ( G ( x 1 ) –G ( x 0 )) / dx At box 714B, the first correction value can be calculated. x Latest And can be determined G ( x Latest The value of ), where At box 716B, G ( x Latest The value of ) is compared with a predetermined threshold. If G ( x Latest If the value of ) is less than the predetermined threshold, then the distance to the fault is . x Latest .if G ( x Latest If the value of ) is not less than the predetermined threshold, then x 0 Reset to x Latest And the process restarts from box 706B.
[0055] Once the distance to the fault is determined, control actions can be performed based on that distance. For example, control actions might involve generating an alarm for the operator.
[0056] It should be apparent that the foregoing only relates to certain embodiments of this application and the patents arising therefrom. Many changes and modifications may be made herein by those skilled in the art without departing from the general spirit and scope of the invention as defined by the appended claims and their equivalents.
[0057] Further aspects of the invention are provided by the subject matter of the following provisions: 1. A method for determining the distance to a fault in a hybrid line system, comprising: calculating a first set of voltage phasors and a first set of current phasors based at least in part on a set of measured voltage samples and a set of measured current samples; calculating ABCD parameters associated with the hybrid line system based at least in part on input line parameters associated with the hybrid line system; calculating a second set of voltage phasors and a second set of current phasors based at least in part on the first set of voltage phasors, the first set of current phasors, and the ABCD parameters; collecting faulty phase voltage phasors and faulty phase current phasors based at least in part on the second set of voltage phasors and the second set of current phasors; identifying a fault in a faulty section of the hybrid line system and parameters associated with the fault based at least in part on the faulty phase voltage phasors and faulty phase current phasors; and calculating the distance to the fault based at least in part on the parameters associated with the fault.
[0058] 2. The method according to Clause 1, wherein the input line parameters include at least the line length of each segment of the hybrid line system, the positive-sequence impedance per length of each segment of the hybrid line system, the zero-sequence impedance per length of each segment of the hybrid line system, the positive-sequence admittance per length of each segment of the hybrid line system, and the zero-sequence admittance per length of each segment of the hybrid line system.
[0059] 3. The method according to any of the foregoing clauses, wherein the first set of voltage phasors and the first set of current phasors are calculated by applying a Fourier transform with attenuated DC (DC) removed components to a set of measured voltage samples and a set of measured current samples.
[0060] 4. The method according to any of the foregoing clauses, wherein identifying a fault in a faulty section of the hybrid line system and parameters associated with the fault further includes: determining that a first section of the hybrid line system does not meet a first condition; determining that a second section of the hybrid line system meets a second condition; and determining that the fault is located in the second section of the hybrid line system.
[0061] 5. The method according to any of the foregoing clauses, wherein the first condition and the second condition are based on whether the fault is a single-phase-to-ground fault or a phase-to-phase fault, and wherein a phase-to-phase fault is associated with a real function condition, and wherein a single-phase-to-ground fault is associated with an imaginary function condition.
[0062] 6. The method according to any of the foregoing clauses, wherein the faulty phase voltage phasor and the faulty phase current phasor are determined at least in part based on the type of fault associated with the fault.
[0063] 7. The method according to any of the foregoing clauses, wherein the first set of voltage phasors and the first set of current phasors are associated with the first bus of the hybrid line system.
[0064] 8. The method according to any of the foregoing clauses, wherein the second set of voltage phasors and the second set of current phasors are associated with the second bus of the hybrid line system.
[0065] 9. A method for determining the distance to a fault in a hybrid line system, comprising: receiving a set of measured voltage samples and a set of measured current samples at a first bus of the hybrid line system; calculating a first set of voltage phasors and a first set of current phasors based at least in part on the set of measured voltage samples and the set of measured current samples; receiving input line parameters associated with the hybrid line system; calculating ABCD parameters associated with the hybrid line system based at least in part on the input line parameters; calculating a second set of voltage phasors and a second set of current phasors at a second bus of the hybrid line system based at least in part on the first set of voltage phasors, the first set of current phasors, and the ABCD parameters; collecting faulty phase voltage phasors and faulty phase current phasors based at least in part on the second set of voltage phasors and the second set of current phasors; identifying a fault in a faulty section of the hybrid line system and parameters associated with the fault based at least in part on the faulty phase voltage phasors and faulty phase current phasors; and calculating the distance to the fault based at least in part on the parameters associated with the fault.
[0066] 10. The method according to any of the foregoing clauses, wherein the input line parameters include at least the line length of each segment of the hybrid line system, the positive-sequence impedance per length of each segment of the hybrid line system, the zero-sequence impedance per length of each segment of the hybrid line system, the positive-sequence admittance per length of each segment of the hybrid line system, and the zero-sequence admittance per length of each segment of the hybrid line system.
[0067] 11. The method according to any of the foregoing clauses, wherein the first set of voltage phasors and the first set of current phasors are calculated by applying a Fourier transform with attenuated DC (DC) removed component to the set of measured voltage samples and the set of measured current samples.
[0068] 12. The method according to any of the foregoing clauses, wherein identifying a fault in a faulty section of the hybrid line system and parameters associated with the fault further comprises: determining that a first section of the hybrid line system does not meet a first condition; determining that a second section of the hybrid line system meets a second condition; and determining that the fault is located in the second section of the hybrid line system.
[0069] 13. The method according to any of the foregoing clauses, wherein the first condition and the second condition are based on whether the fault is a single-phase-to-ground fault or a phase-to-phase fault, and wherein a phase-to-phase fault is associated with a real function condition, and wherein a single-phase-to-ground fault is associated with an imaginary function condition.
[0070] 14. The method according to any of the foregoing clauses, wherein the faulty phase voltage phasor and the faulty phase current phasor are determined at least in part based on the type of fault associated with the fault.
[0071] 15. A hybrid line system comprising: a first section having a first busbar; and a second section having a second busbar, wherein a first set of voltage phasors and a first set of current phasors are calculated based at least in part on a set of measured voltage samples and a set of measured current samples associated with the first section, and wherein ABCD parameters associated with the hybrid line system are calculated based at least in part on input line parameters associated with the hybrid line system, and wherein a second set of voltage phasors and a second set of current phasors associated with the second section are calculated based at least in part on the first set of voltage phasors, the first set of current phasors, and the ABCD parameters, and wherein faulty phase voltage phasors and faulty phase current phasors are collected based at least in part on the second set of voltage phasors and the second set of current phasors, and wherein faults in the faulty section of the hybrid line system and parameters associated with the faults are identified based at least in part on the faulty phase voltage phasors and faulty phase current phasors.
[0072] 16. The hybrid line system according to any of the foregoing clauses, wherein the input line parameters include at least: the line length of each segment of the hybrid line system, the positive-sequence impedance per length of each segment of the hybrid line system, the zero-sequence impedance per length of each segment of the hybrid line system, the positive-sequence admittance per length of each segment of the hybrid line system, and the zero-sequence admittance per length of each segment of the hybrid line system.
[0073] 17. A hybrid line system according to any of the foregoing clauses, wherein the first set of voltage phasors and the first set of current phasors are calculated by applying a Fourier transform with attenuated DC (DC) removed component to the set of measured voltage samples and the set of measured current samples.
[0074] 18. The hybrid line system according to any of the foregoing clauses, wherein identifying a fault in a faulty section of the hybrid line system and determining parameters associated with the fault further includes: determining that a first section of the hybrid line system does not meet a first condition; determining that a second section of the hybrid line system meets a second condition; and determining that the fault is located in the second section of the hybrid line system.
[0075] 19. A hybrid line system according to any of the foregoing clauses, wherein the first condition and the second condition are based on whether the fault is a single-phase-to-ground fault or a phase-to-phase fault, and wherein a phase-to-phase fault is associated with a real function condition, and wherein a single-phase-to-ground fault is associated with an imaginary function condition.
[0076] 20. A hybrid line system according to any of the foregoing clauses, wherein the faulty phase voltage phasor and the faulty phase current phasor are determined at least in part based on the type of fault associated with the fault.
Claims
1. A method for determining the distance to a fault in a hybrid line system, comprising: The first set of voltage phasors (306A-C) and the first set of current phasors (308A-C) are calculated based at least in part on a set of measured voltage samples (302A-C) and a set of measured current samples (304A-C). The ABCD parameters associated with the hybrid line system are calculated, at least in part, based on the input line parameters associated with the hybrid line system. The second set of voltage phasors and the second set of current phasors are calculated based at least in part on the first set of voltage phasors (306A-C), the first set of current phasors (308A-C), and the ABCD parameters. Based at least in part on the second set of voltage phasors and the second set of current phasors, the faulty phase voltage phasors and the faulty phase current phasors are collected. The fault in the faulty section of the hybrid line system and the parameters associated with the fault are identified, at least in part based on the faulty phase voltage phasor and the faulty phase current phasor. as well as The distance to the fault is calculated based at least in part on the parameters associated with the fault.
2. The method according to claim 1, wherein, The input line parameters include at least the line length of each segment of the hybrid line system, the positive-sequence impedance per length of each segment of the hybrid line system, the zero-sequence impedance per length of each segment of the hybrid line system, the positive-sequence admittance per length of each segment of the hybrid line system, and the zero-sequence admittance per length of each segment of the hybrid line system.
3. The method according to claim 1, wherein, The first set of voltage phasors (306A-C) and the first set of current phasors (308A-C) are calculated by applying a Fourier transform with attenuated DC (DC) removal component to the set of measured voltage samples (302A-C) and the set of measured current samples (304A-C).
4. The method according to claim 1, wherein, Identifying the fault in a faulty section of the hybrid line system and the parameters associated with the fault further includes: It is determined that the first section of the hybrid line system does not meet the first condition; Determine that the second section of the hybrid line system satisfies the second condition; and The fault is determined to be located in the second section of the hybrid line system.
5. The method according to claim 4, wherein, The first condition and the second condition are based on whether the fault is a single-phase ground fault or a phase-to-phase fault, wherein the phase-to-phase fault is associated with a real function condition, and wherein the single-phase ground fault is associated with an imaginary function condition.
6. The method according to claim 1, wherein, The faulty phase voltage phasor and the faulty phase current phasor are determined at least in part based on the type of fault associated with the fault.
7. The method according to claim 1, wherein, The first set of voltage phasors (306A-C) and the first set of current phasors (308A-C) are associated with the first bus of the hybrid line system.
8. The method according to claim 7, wherein, The second set of voltage phasors and the second set of current phasors are associated with the second bus of the hybrid circuit system.
9. A hybrid line system, comprising: The first section has a first busbar; as well as The second section has a second busbar; The first set of voltage phasors (306A-C) and the first set of current phasors (308A-C) are calculated based at least in part on a set of measured voltage samples (302A-C) and a set of measured current samples (304A-C) associated with the first segment. Furthermore, at least in part, the ABCD parameters associated with the hybrid line system are calculated based on the input line parameters associated with the hybrid line system. Furthermore, at least in part, the second set of voltage phasors and the second set of current phasors associated with the second segment are calculated based on the first set of voltage phasors (306A-C), the first set of current phasors (308A-C), and the ABCD parameters. And at least in part, the faulty phase voltage phasors and faulty phase current phasors are collected based on the second set of voltage phasors and the second set of current phasors. Furthermore, the faults in the faulty sections of the hybrid line system and the parameters associated with the faults are identified based at least in part on the faulty phase voltage phasors and the faulty phase current phasors.
10. The hybrid circuit system according to claim 9, wherein, The input line parameters include at least the line length of each segment of the hybrid line system, the positive-sequence impedance per length of each segment of the hybrid line system, the zero-sequence impedance per length of each segment of the hybrid line system, the positive-sequence admittance per length of each segment of the hybrid line system, and the zero-sequence admittance per length of each segment of the hybrid line system.
11. The hybrid circuit system according to claim 9, wherein, The first set of voltage phasors (306A-C) and the first set of current phasors (308A-C) are calculated by applying a Fourier transform with attenuated DC (DC) removal component to the set of measured voltage samples (302A-C) and the set of measured current samples (304A-C).
12. The hybrid circuit system according to claim 9, wherein, The identification of the faults in the faulty sections of the hybrid line system and the parameters associated with the faults further includes: It is determined that the first segment of the hybrid line system does not meet the first condition; Determine that the second segment of the hybrid line system satisfies the second condition; and The fault is determined to be located in the second section of the hybrid line system.
13. The hybrid line system according to claim 12, wherein, The first and second conditions are based on whether the fault is a single-phase ground fault or a phase-to-phase fault, wherein the phase-to-phase fault is associated with a real function condition, and wherein the single-phase ground fault is associated with an imaginary function condition.
14. The hybrid circuit system according to claim 9, wherein, The faulty phase voltage phasor and the faulty phase current phasor are determined at least in part based on the type of fault associated with the fault.
15. The hybrid circuit system according to claim 9, wherein, The first set of voltage phasors (306A-C) and the first set of current phasors (308A-C) are associated with the first bus, and the second set of voltage phasors and the second set of current phasors are associated with the second bus.