System and method for determining the distance to failure in a hybrid line system

Abstract

This application provides a method for determining the distance to a fault in a hybrid line system. The method may include: calculating a first set of voltage phasors and current phasors based on at least a portion of measured voltage samples and measured current samples; calculating ABCD parameters associated with the hybrid line system based on at least a portion of input line parameters; calculating a second set of voltage phasors and current phasors based on at least a portion of the first set of voltage phasors, current phasors and ABCD parameters; collecting fault phase voltage phasors and current phasors based on at least a portion of the second set of voltage phasors and current phasors; identifying faults and associated parameters in the fault section of the hybrid line system based on at least a portion of the fault phase voltage phasors and current phasors; and calculating the distance to the fault based on at least a portion of the associated parameters.

Description

[Technical Field]

[0001] This application and the resulting patents relate in general to hybrid line systems, and more specifically to systems and methods for determining the distance to failure within a hybrid line system. [Background technology]

[0002] Generally speaking, the location of a fault in a cable and / or hybrid line system differs from the location of a fault in the transmission line. This difference is partly due to the importance of considering the shunt capacitance of the cable. This difference is also partly due to the nonlinear nature of the line impedance (or other line parameters) with respect to line length, which is caused by the dispersion parameters along the line and / or cable.

[0003] Therefore, there is a growing need for methods to accurately calculate the distance to failure in certain types of systems based on single-end measurements, such as systems including hybrid lines, line systems with multiple sections, systems including underground cables, and / or systems including overhead lines exceeding 100 kilometers in length. This can be achieved by applying a network with distributed ABCD parameters (i.e., ABCD transmission parameters created by the distributed primary parameters of the line or cable). If the failure is a single-phase-to-ground fault with higher fault resistance, a zero-phase network with distributed ABCD parameters may be used to locate the fault. If the failure is a phase-to-phase fault with higher fault resistance, a negative-phase network with distributed ABCD parameters may be used to locate the fault. The advantages of using the variance ABCD parameter include improved accuracy in zone location, as well as distance-to-fault localization using single-ended measurements with an error rate of less than 2% for both single-phase-to-ground faults and phase-to-phase-to-ground faults (including three-phase faults, and phase-to-phase-to-ground faults) with a resistance of 20 ohms and a source impedance ratio (SIR) of 10.

[0004] The fault location remains accurate even as fault resistance increases. This is partly due to fault location analysis that takes into account the type of fault present, and separate fault location algorithms can be implemented for single-phase-to-ground faults and phase-to-phase (including three-phase, phase-to-phase-to-ground) faults. This is further partly due to the fact that the fault location is calculated using the Newton-Raphson method because the derivative of the fault location function cannot be analytically expressed. Furthermore, the fault section detection process utilizes a discrimination criterion that compares the virtual phasor calculated for each section with the local phasor. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2019 / 229638 [Overview of the project]

[0006] Accordingly, the present 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 steps of: calculating a first set of voltage phasors and a first set of current phasors based on at least a portion of a set of measured voltage samples and a set of measured current samples; calculating ABCD parameters associated with a hybrid line system based on at least a portion of input line parameters associated with the hybrid line system; calculating a second set of voltage phasors and a second set of current phasors based on the first set of voltage phasors, the first set of current phasors, and at least a portion of the ABCD parameters; collecting fault phase voltage phasors and fault phase current phasors based on at least a portion of the second set of voltage phasors and the second set of current phasors; identifying faults and fault-associated parameters in a fault section of the hybrid line system based on at least a portion of the fault-associated parameters; and calculating the distance to a fault based on at least a portion of the fault-associated parameters.

[0007] This application and the resulting patent further provide a method for determining the distance to failure in a hybrid line system. The method may include the steps of: receiving a set of measured voltage samples and a set of measured current samples on a first bus of a hybrid line system; calculating a first set of voltage phasors and a first set of current phasors based on at least a portion of 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 on at least a portion of the input line parameters; calculating a second set of voltage phasors and a second set of current phasors on a second bus of the hybrid line system based on the first set of voltage phasors, a first set of current phasors, and at least a portion of the ABCD parameters; collecting fault phase voltage phasors and fault phase current phasors based on at least a portion of the second set of voltage phasors and the second set of current phasors; identifying faults and fault-associated parameters in a fault section of the hybrid line system based on at least a portion of the fault-associated parameters; and calculating the distance to the fault based on at least a portion of the fault-associated parameters.

[0008] This application and the resulting patent further provide a hybrid line system. The hybrid line system may include a first section having a first bus and a second section having a second bus, wherein a first set of voltage phasors and a first set of current phasors are calculated based on at least a portion of a set of measured voltage samples and a set of measured current samples associated with the first section, ABCD parameters associated with the hybrid line system are calculated based on at least a portion of input line parameters associated with the hybrid line system, a second set of voltage phasors and a second set of current phasors associated with the second section are calculated based on the first set of voltage phasors, the first set of current phasors, and at least a portion of the ABCD parameters, fault phase voltage phasors and fault phase current phasors are collected based on at least a portion of the second set of voltage phasors and a second set of current phasors, and faults and parameters associated with faults in the fault section of the hybrid line system are identified based on at least a portion of fault phase voltage phasors and fault phase current phasors.

[0009] These and other features of this application and the resulting patent will become apparent to those skilled in the art by considering the following detailed description in conjunction with some drawings and the attached claims. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an algorithm for calculating the distance to failure based on ABCD parameters, according to one or more exemplary embodiments of the present disclosure. [Figure 2] This is a schematic diagram of a hybrid line system according to one or more exemplary embodiments of the present disclosure. [Figure 3A] This is a schematic diagram of the algorithm for performing phasor calculations according to the algorithm shown in Figure 1. [Figure 3B]This is a schematic diagram of the algorithm for performing phasor calculations according to the algorithm shown in Figure 1. [Figure 4] Figure 1 is a schematic diagram of the algorithm for performing phasor calculations on the next bus based on the ABCD parameters, according to the algorithm shown in Figure 1. [Figure 5] This is a schematic diagram of the algorithm for collecting fault phasors according to the algorithm shown in Figure 1. [Figure 6A] Figure 1 is a schematic diagram of the algorithm for identifying faulty sections according to the algorithm. [Figure 6B] Figure 1 is a schematic diagram of the algorithm for identifying faulty sections according to the algorithm. [Figure 7] Figure 1 is a flowchart showing the calculation of the distance to failure using the algorithm. [Modes for carrying out the invention]

[0011] Next, referring to the drawings, similar symbols indicate similar elements across several figures, and Figure 1 is a schematic diagram 100 for calculating the distance to failure based on ABCD parameters. Schematic diagram 100 may be applicable to fault distance calculations for multi-section hybrid overhead lines or cables. In block 102, voltage phasors and current phasors can be calculated by applying a Fourier transform with attenuated DC rejection components to single-end measured voltage and current samples. This process may be further illustrated in Figures 3A and 3B. In block 104, positive-sequence and zero-sequence ABCD parameters for each section of the hybrid line system can be calculated based on the line parameters of the corresponding section. Line parameters may include positive-sequence and zero-sequence series impedances as well as shunt admittance per length for each corresponding section. Line parameters may be entered by the user. This process may be further illustrated in Figure 4.

[0012] In block 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 in block 102 and the ABCD parameters calculated in block 104. Further, the reverse-phase and zero-phase source impedances of each bus can also be calculated. In block 108, the fault-phase voltage phasor and current phasor can be collected together with the corresponding parameters for the fault-phase voltage phasor and current phasor. This process can be further shown in FIG. 5. In block 110, the fault section can be identified based on the comparison of the calculated fault-phase voltage phasors with each other, or the comparison of the calculated fault-phase voltage phasor with the zero-phase current of the corresponding section. When the fault section is identified, the corresponding voltage phasor and current phasor, as well as the corresponding parameters, can be collected. This process can be further shown in FIGS. 6A - 6B. In block 112, the distance to the fault is calculated by a fault location determination algorithm based on the ABCD parameters, based on the identified fault-phase voltage phasor and current phasor. This process can be further shown in FIG. 7.

[0013] FIG. 2 is a schematic diagram 200 of a hybrid line system. As shown in FIG. 2, the hybrid line system can have N - 1 sections. Thus, section 1 (S1) can be associated with a specific voltage U S1 and current I S1 . Section 2 (S2) can be associated with a specific voltage U S2 and current I S2 . Each subsequent section can be associated with a specific voltage U Sk and current I Sk , where k represents the k-th section. The last section (SN - 1) can be associated with a specific voltage U SN-1 and current I SN-1 . The last section (SN - 1) can end at bus SN which can be associated with a specific voltage U SN .

[0014] Figure 3A is a schematic diagram 300A of the algorithm for performing phasor calculations according to the algorithm shown in Figure 1. The algorithm for performing phasor calculations can be applied in block 102 of Figure 1. The algorithm can perform phasor calculations by performing a Fourier transform with attenuated DC rejection. At the local end, samples of each phase voltage and phase current can be measured. The samples are u a (n)302A, u b (n)302B, and u c (n) Three-phase voltage such as 302C, and i a (n)304A, i b (n)304B, and i c (n) May include three-phase currents such as 304C. Three-phase voltage 302A~C and three-phase current 304A~C may be inputs to the algorithm. a (n)302A, u b (n)302B, u c (n)302C, i a (n)304A, i b (n)304B, and i c (n)304C is the input, and after undergoing a Fourier transform with the attenuated DC rejection component, the algorithm is U a (n)306A, U b (n)306B, U c (n)306C, I a (n)308A, I b (n)308B, and I c (n)308C can be output respectively. Output U a (n)306A, U b (n)306B, and U c (n)306C may represent a set of voltage phasors, while output I a (n)308A, I b (n)308B, and I c (n)308C may represent a set of current phasors.

[0015] Figure 3B is a further schematic diagram for performing phasor calculations according to the algorithm shown in Figure 1. More specifically, Figure 3B shows the process of performing a Fourier transform with a decayed DC rejection component. First, the input x(n) (e.g., u a (n)302A, u b (n)302B, u c (n)302C, i a (n)304A, i b (n)304B, or i c (n)304C) is a cosine filter COS F (n) This can be applied to 310. The coefficients of the cosine filter 310 may be as follows:

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[0016] 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: RealX(n)=y(n-1) Therefore, the real component 312 is z at the output of the cosine filter 310. -1 The imaginary component 314 can be determined in part based on the application of the function.

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[0017] Figure 4 is a schematic diagram of the algorithm for performing phasor calculations in the next bus based on the ABCD parameters. In order to perform phasor calculations in the next bus based on the ABCD parameters, the ABCD parameters must first be calculated. Each line section L Sk The line length can be identified, where Sk is the k-th section, and k = 1, 2, ..., N-1. Sk The line length can be entered by the user. The positive and zero-sequence impedances and admittance per unit length of each line section can also be identified and entered by the user. The length can be expressed in kilometers, meters, or miles. The positive-sequence impedance is z 1Sk It can be written as such, and the zero-sequence impedance is z 0Sk It can be written as, and the positive admittance is y 1Sk It can be written as, and zero-phase admittance is y 0Sk It can be written as: Line section L Sk In the case of overhead lines, in contrast to cables, positive and zero-sequence admittance y 1Sk and y 0Sk Since the positive and zero-sequence admittances y can be calculated as follows, 1Sk and y 0Sk This does not need to be entered by the user:

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[0018] Each line EL Sk The line length, and the length z 1Sk , z 0Sk , y 1Sk , and y 0Sk After the positive and zero-sequence impedances and admittances per unit are input and / or calculated, the positive-sequence ABCD parameters and zero-sequence ABCD parameters can be calculated. 1Sk B 1Sk , C 1Sk , and D 1Sk The positive-sequence ABCD parameters can be calculated as follows: A 1Sk =cosh(γ 1Sk L Sk ) B 1Sk =-Z C1Sk sinh(γ 1Sk L Sk )

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[0019] As shown in FIG. 4, the positive-phase and zero-phase ABCD parameters, voltage phasors (e.g., as shown in FIG. 3A, U a (n)306A, U b (n)306B, and U c (n)306C), and current phasors (e.g., as shown in FIG. 3A, I a (n)308A, I b (n)308B, and I c (n)308C) can function as inputs to the ABCD algorithm component. The ABCD algorithm component can receive the inputs and apply the ABCD algorithm to calculate the voltage phasor and current phasor on the next bus.

[0020] To calculate the voltage phasor and current phasor on the next bus, the ABCD algorithm component can execute the ABCD algorithm as follows: U aSk+1 = A 1Sk U aSk + B 1Sk I aSk +(A 0Sk - A 1Sk )U 0Sk +(B 0Sk - B 1Sk )I 0Sk U bSk+1 = A1Sk U bSk +B 1Sk I bSk +(A 0Sk -A 1Sk )U 0Sk +(B 0Sk -B 1Sk )I 0Sk U cSk+1 =A 1Sk U cSk +B 1Sk I cSk +(A 0Sk -A 1Sk )U 0Sk +(B 0Sk -B 1Sk )I 0Sk I aSk+1 =C 1Sk U aSk +D 1Sk I aSk +(C 0Sk -C 1Sk )U 0Sk +(D 0Sk -D 1Sk )I 0Sk I bSk+1 =C 1Sk U bSk +D 1Sk I bSk +(C 0Sk -C 1Sk )U 0Sk +(D 0Sk -D 1Sk )I 0Sk I cSk+1 =C 1Sk U cSk +D 1Sk I cSk +(C 0Sk -C 1Sk )U 0Sk +(D 0Sk -D 1Sk )I 0Sk where

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[0021] Therefore, the ABCD algorithm can be used to calculate the voltage phasor and current phasor in the next bus in the hybrid line system. For example, referring back to Figure 2, the hybrid line system is U S1 The three-phase voltage and I S1 Section 1 (S1) has a three-phase current, and U S2 The three-phase voltage and I S2 Section 2 (S2) having a three-phase current, and any number of subsequent sections, U SN-1 The three-phase voltage and I SN-1 The last section (SN-1) has a three-phase current, and the last section may have U SN The bus ends at SN having a three-phase voltage. Therefore, in S1, the first ABCD algorithm component 402 has a voltage U S1 Three voltage phasors corresponding to (U aS1 (n), U bS1 (n), and U cS1 (n)), current I S1 Three current phasors corresponding to (I aS1 (n), I bS1 (n), and I cS1 (n)) Positive-sequence ABCD parameters for S1 (ABCD 1S1 ), as well as the zero-sequence ABCD parameter (ABCD) for S1. 0S1 ) can be received as input. Next, the first ABCD algorithm component 402 has three voltage phasors (U aS2 (n), U bS2 (n), and U cS2 (n)), as well as the three current phasors in S2 (I aS2 (n), I bS2 (n), and I cS2The ABCD algorithm can be applied to calculate (n).

[0022] Next, the voltage phasor (U) in S2 aS2 (n), U bS2 (n), and U cS2 (n)), and the current phasor in S2 (I aS2 (n), I bS2 (n), and I cS2 (n)) can be used as input to the second ABCD algorithm component 404. The second ABCD algorithm component 404 also takes the positive-phase ABCD parameter (ABCD) in S2. 1S2 ) and zero-phase ABCD parameters in S2 (ABCD 0S2 The input may be ) . The second ABCD algorithm component 404 may then apply the ABCD algorithm to calculate the voltage phasors and current phasors in subsequent sections of the hybrid line system. This process may be repeated for the same number of sections present in the hybrid line system.

[0023] As shown in Figure 4, the third ABCD algorithm component 406 receives the voltage phasor (U) from the second last section SN-2. aSN-2 (n), U bSN-2 (n), and U cSN-2 (n)), as well as current phasor (I aSN-2 (n), I bSN-2 (n), and I cSN-2 It is configured to receive (n)) as input. The third ABCD algorithm component 406 also receives the positive-phase ABCD parameters (ABCD) in SN-2. 1SN-2 ) and zero-phase ABCD parameters in SN-2 (ABCD 0SN-2 ) can be received as input. Next, the third ABCD algorithm component can receive the voltage phasor (U) in the last section SN-1 of the hybrid line system. aSN-1 (n), U bSN-1 (n), and U cSN-1(n)), as well as current phasor (I aSN-1 (n), I bSN-1 (n), and I cSN-1 The ABCD algorithm can be applied to calculate (n).

[0024] At the end of the hybrid line system represented by point SN, the fourth ABCD algorithm component 408 is a voltage phasor (U) from the last section SN-1. aSN-1 (n), U bSN-1 (n), and U cSN-1 (n)), as well as current phasor (I aSN-1 (n), I bSN-1 (n), and I cSN-1 It is configured to receive (n)) as input. The fourth ABCD algorithm component 408 also receives the positive-phase ABCD parameters (ABCD) in SN-1. 1SN-1 ) and zero-phase ABCD parameters in SN-1 (ABCD 0SN-1 ) can be received as input. Next, the fourth ABCD algorithm component 408 calculates the voltage phasor (U) at the last point SN of the hybrid line system. aSN (n), U bSN (n), and U cSN (n)), as well as current phasor (I aSN (n), I bSN (n), and I cSN The ABCD algorithm can be applied to calculate (n).

[0025] Figure 5 shows a schematic diagram of the algorithm for collecting fault phasors. After the voltage and current phasors for each bus of the hybrid line system have been calculated and / or collected, the fault phase voltage and current phasors, along with their corresponding parameters, can be collected by the external display DDB_TF_PHS for fault phase selection. The voltage and current phasors for the first bus are the voltage and current phasors measured at the beginning of the hybrid line system. The voltage and current phasors for subsequent buses are calculated using the ABCD algorithm, for example, the ABCD algorithm shown in Figure 4.

[0026] Therefore, the input to the fault phasor acquisition component 502 may include the fault phase indicator DDB_FT_PHS and each set of calculated and / or acquired voltage and current phasors in each bus of the hybrid line system. For example, the input may include U, representing the voltage and current phasors in the first section of the hybrid line system (e.g., section 1 S1 in Figure 2). aS1 , U bS1 , U cS1 , I aS1 , I bS1 , and I cS1 These phasors may include the first section of the hybrid line system, U aS1 , U bS1 , U cS1 , I aS1 , I bS1 , and I cS1 This can be determined by the voltage and current phasors measured at the starting point of the hybrid line system. That is, U aS1 =U a , U bS1 =U b , U cS1 =U c , I aS1 =I a , I bS1 =I b , and I cS1 =I c That is. Other inputs are U aS2 , U bS2 , UcS2 , I aS2 , I bS2 , and I cS2 This may include voltage and current phasors in the second section of the hybrid line system (e.g., section 2 S2 in Figure 2). Additional inputs may include voltage and current phasors in any subsequent section of the hybrid line system. Another input may include voltage and current phasors at the end of the last bus of the hybrid line system, i.e., the end of the last section of the hybrid line system. These voltage and current phasors are U aSN , U bSN , U cSN , I aSN , I bSN , and I cSN It can be represented as follows.

[0027] After receiving the input, the fault phasor collection component 502 may apply the following principle to collect the fault voltage and / or current phasors:

[0028] If DDB_FT_PHS indicates that the fault is a phase-A-to-ground fault, the following equation may apply. U RSk =U aSk k=1,2,...,N I RSk =I aSk k=1,2,...,N

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[0029] If DDB_FT_PHS indicates that the fault is a phase-B-to-ground fault, the following equation may apply. U RSk =U bSk k=1,2,...,N I RSk =I bSk k=1,2,...,N

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[0030] If DDB_FT_PHS indicates that the fault is a phase-C-to-ground fault, the following equation may apply. U RSk =U cSk k=1,2,...,N I RSk =I cSk k=1,2,...,N

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[0031] If DDB_FT_PHS indicates that the fault is a phase-A to-B fault, a phase-A to-B to-ground fault, a phase-A to-B to-C fault, or a phase-A to-B to-C to-ground fault, the following equality may apply. U RSk =U aSk -U bSk k=1,2,...,N I RSk =I aSk -I bSk k=1,2,...,N

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[0032] If DDB_FT_PHS indicates that the fault is a phase-B to-C fault or a phase-B to-C to-ground fault, the following equation may apply. U RSk =U bSk -U cSk k=1,2,...,N I RSk =I bSk -I cSk k=1,2,...,N

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[0033] If DDB_FT_PHS indicates that the fault is a phase-C-to-A fault or a phase-C-to-A-to-ground fault, the following equation may apply. U RSk =U cSk -U aSk k=1,2,...,N I RSk =I cSk -I aSk k=1,2,...,N

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[0034] The fault phasor acquisition component 502 performs U for each set of voltage and current phasors received by the fault phasor acquisition component. RSk , I RSk , U 0NegSk , and I 0NegSk To determine this, the DDB_FT_PHS input and an appropriate equation can be used. For example, U aS1 , U bS1 , U cS1 , I aS1 , I bS1 , and I cS1 In response to receiving the signal, the fault phasor acquisition component 502 controls the U RS1 , I RS1 , U 0NegS1 , and I 0NegS1 It can output U aS2 , U bS2 , U cS2 , I aS2 , I bS2 and I cS2In response to receiving the signal, the fault phasor acquisition component 502 controls the U RS2 , I RS2 , U 0NegS2 , and I 0NegS2 It can output U aSN , U bSN , U cSN , I aSN , I bSN , and I cSN In response to receiving the signal, the fault phasor acquisition component 502 controls the U RSN , I RSN , U 0NegSN , and I 0NegSN It can output the following.

[0035] Figure 6A is a schematic diagram 600A of an algorithm for identifying a fault section in a hybrid line system, for example. The algorithm may include a source impedance calculation component 602 and a fault section identification and parameter acquisition component 604. The source impedance calculation component 602 takes input U 0NegSk , I 0NegSk , ABCD 0Sk , and ABCD 1Sk It can receive at least one set of inputs, and one set of inputs is received for each section of the hybrid line system. For example, the source impedance calculation component 602 can receive U for a hybrid line system having N-1 sections. 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 may also receive DDB_FT_PHS as input.

[0036] The source impedance calculation component 602 can use these inputs to calculate the following output: z for each section SourceSkL z for each sectionSourceSkR , and ABCD for each section Sk That is, if the hybrid line system has N-1 sections, the source impedance calculation component 602 calculates z SourceS1L ,...,z SourceSN-1L , z SourceS1R ,...,z SourceSN-1R , ABCD S1 ,...,ABCDS N-1 The following can be output, which can then function as inputs to the fault section identification and parameter acquisition component 604. The local and remote source impedances can be calculated as follows:

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[0037] Other inputs to the fault section identification and parameter acquisition component 604 are as follows, for each section U RSk I for each section RSk , and I for each section 0NegSk This may include: For example, if a hybrid line system has N-1 sections and the N-1th section terminates at bus SN, the fault section identification and parameter acquisition component 604 has the following input U RS1 , I RS1 , I 0NegS1 ,...,URSN , I RSN , and I 0NegSN These inputs may be received. These inputs may be output by a fault phasor acquisition component, for example, the fault phasor acquisition component 502 shown in Figure 5. The fault section identification and parameter acquisition component 604 can then determine the faulty section in the hybrid line system.

[0038] An algorithm 600B for identifying a faulty section is shown in Figure 6B. The 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, the faulty section identification and parameter collection component 604 may include faulty S1 section identification components 606,..., and faulty SN-1 section identification component 608. Each of the faulty section identification components for each section takes U as input. RSk , U RSk+1 , I 0NegSk , and DDB_FT_PHS can be received. For example, fault S1 section identification component 606 is U RS1 , U RS2 , I 0NegS1 , and DDB_FT_PHS may be received as input. Fault SN-1 section identification component 608 is U RSN-1 , U RSN , I 0NegSN-1 , and DDB_FT_PHS can be received as input.

[0039] Each fault section identification component for each section in a hybrid line system may be configured to generate an output DDB_FT_SECT_Sk indicating whether the section is faulty or not. For example, faulty S1 section identification component 606 may output DDB_FT_SECT_S1, which determines whether S1 is faulty, and faulty SN-1 section identification component 608 may output DDB_FT_SEC_SN-1, which determines whether SN-1 is faulty. The following conditions may apply to generate the output DDB_FT_SECT_Sk for each fault section identification component (e.g., faulty S1 section identification component 606 and faulty SN-1 section identification component 608). If the fault is a phase-to-phase fault, a phase-to-phase-to-ground fault, or a three-phase fault, the following conditions apply:

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[0040] The outputs of various DDB_FT_SECT_Sk values, where k=1,2,...,N-1, can be input to the final logic component 610, which can be configured to determine the faulty section in the hybrid line system. The final logic component 610 can generate a table of DDB_FT_SECT_Sk values. Furthermore, the final logic component 610 can determine that the k-th section is faulty if DDB_FT_SECT_Sk=1 and DDB_FT_SECT_Sk-1=0. Thus, the final logic component 610 can output a DDB_FT_SECT that identifies the faulty section(s) in the hybrid line system.

[0041] Returning to Figure 6A, after identifying the faulty section(s), the faulty section identification and parameter collection component 604 performs the following for each faulty section: R , I R , U 0Neg , I 0Neg , z SourceL , z SourceR It may output L and DDB_FT_SECT. These outputs represent parameters associated with the faulty section that can be used to identify the faulty section, the corresponding voltage, the corresponding current, and the distance to the fault. If the k-th section is identified as a faulty section, the faulty section identification and parameter collection component 604 outputs the following 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 SourceSkR This may generate the following. Other outputs may include positive-sequence and zero-sequence ABCD parameters associated with each fault section.

[0042] Next, using the output parameters, the distance to failure can be calculated by applying the following formula: G(x) = imag[V F (x)conj(C f (x)I 0Neg ]=0 If the fault is indicated to be a single-phase to ground fault, the voltage at the fault point is calculated as follows: V F (x) = A1(x)U R +B1(x)I R +(A0(x)-A1(x))U 0Neg +(B0(x)-B1(x))I 0Neg Fault current distribution coefficient C f (x) can be calculated as follows:

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[0043] Figure 7 shows a flowchart 700 for calculating the distance to a fault. First, the voltage and current phasors of the faulty section, the length and ABCD parameters of the faulty section, the local and remote equivalent source impedances of the faulty section, and the phase information of the faulty section are known. In block 702, it can be determined whether the fault is a single-line-to-ground (SLG) fault. If the fault is a single-line-to-ground (SLG) fault, in block 704A, the initial values ​​of x, x0 can be set to half the line length. In block 706A, in the case of a single-line-to-ground fault, V F (x) and C f (x) can be calculated as follows: V F (x) = A1(x)U R +B1(x)I R +(A0(x)-A1(x))V 0NEg +(B0(x)-B0(x)))*I 0Neg

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[0044] In block 710A, the value of x can be incremented from x0 to x1, where x1 = x0 + dx, and a function of G(x1) can be calculated. That is, G(x1) = imag(V) F (x1)*conj(C f (x1)))*I 0Neg ) The derivative of G(x) with respect to x can be calculated in block 712A. That is, G'(x) = (G(x1) - G(x0)) / dx The following can be calculated. In block 714A, the first correction x Latest G(x Latest The value of ) can be determined, and here

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[0045] In block 716A, G(x Latest The value of G(x) is compared to a predetermined threshold. Latest If the value of ) is less than a predetermined threshold, the distance to failure is x Latest G(x Latest If the value of ) is greater than or equal to a predetermined threshold, then x0 is x Latest It is reset, and the process resumes from block 706A.

[0046] If the fault is not a single-line-to-ground (SLG) fault, in block 704B, the initial values ​​of x, x0 may be set to half the line length. In block 706B, V F (x) and C f (x) can be calculated based on the equations described herein. V F (x) = A1(x)U R +B1(x)I R

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[0047] Once the distance to failure is determined, control actions may be taken based on that determination. For example, control actions may include generating a warning to the operator.

[0048] It should be clear that the above pertains only to specific embodiments of this application and the resulting patents. Those skilled in the art will be able to make numerous changes and modifications herein without departing from the general spirit and scope of the invention as defined by the following claims and equivalents.

[0049] Further aspects of the present invention are provided by the subject matter of the following clauses.

[0050] 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 on at least a portion of a set of measured voltage samples and a set of measured current samples; calculating ABCD parameters associated with the hybrid line system based on at least a portion of input line parameters associated with the hybrid line system; calculating a second set of voltage phasors and a second set of current phasors based on the first set of voltage phasors, a first set of current phasors, and at least a portion of the ABCD parameters; collecting fault phase voltage phasors and fault phase current phasors based on at least a portion of the second set of voltage phasors and the second set of current phasors; identifying faults and fault-associated parameters in a fault section of the hybrid line system based on at least a portion of the fault-associated parameters; and calculating the distance to the fault based on at least a portion of the fault-associated parameters.

[0051] 2. The method according to Clause 1, wherein the input line parameters include at least the line length of each section of the hybrid line system, the positive-sequence impedance per unit length of each section of the hybrid line system, the zero-sequence impedance per unit length of each section of the hybrid line system, the positive-sequence admittance per unit length of each section of the hybrid line system, and the zero-sequence admittance per unit length of each section of the hybrid line system.

[0052] 3. The method of any of the preceding clauses, wherein a first set of voltage phasors and a first set of current phasors are calculated by applying a Fourier transform with attenuated DC (DC) rejection components to a set of measured voltage samples and a set of measured current samples.

[0053] 4. The method of any of the preceding clauses, further comprising identifying a fault and parameters associated with the fault in a fault section of a hybrid line system, 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.

[0054] 5. The method as described in either of the preceding clauses, wherein the first and second conditions are based on whether the fault is a single-phase-to-ground fault or a phase-to-phase fault, with the phase-to-phase fault being associated with a real function condition and the single-phase-to-ground fault being associated with an imaginary function condition.

[0055] 6. The method described in any of the preceding clauses, wherein the fault phase voltage phasor and fault phase current phasor are determined based on at least a portion of the type of fault associated with the fault.

[0056] 7. The method described in any of the preceding clauses, wherein a first set of voltage phasors and a first set of current phasors are associated with a first bus of a hybrid line system.

[0057] 8. The method described in any of the preceding clauses, wherein a second set of voltage phasors and a second set of current phasors are associated with a second bus of the hybrid line system.

[0058] 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 in a first bus of the hybrid line system; calculating a first set of voltage phasors and a first set of current phasors based on at least a portion of 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 on at least a portion of the input line parameters; calculating a second set of voltage phasors and a second set of current phasors in a second bus of the hybrid line system based on the first set of voltage phasors, a first set of current phasors, and at least a portion of the ABCD parameters; collecting fault phase voltage phasors and fault phase current phasors based on at least a portion of the second set of voltage phasors and the second set of current phasors; identifying faults and fault-associated parameters in a fault section of the hybrid line system based on at least a portion of the fault-associated parameters; and calculating the distance to the fault based on at least a portion of the fault-associated parameters.

[0059] 10. The method according to any of the preceding clauses, wherein the input line parameters include at least the line length of each section of the hybrid line system, the positive-sequence impedance per unit length of each section of the hybrid line system, the zero-sequence impedance per unit length of each section of the hybrid line system, the positive-sequence admittance per unit length of each section of the hybrid line system, and the zero-sequence admittance per unit length of each section of the hybrid line system.

[0060] 11. The method of any of the preceding clauses, wherein a first set of voltage phasors and a first set of current phasors are calculated by applying a Fourier transform with attenuated DC (DC) rejection components to a set of measured voltage samples and a set of measured current samples.

[0061] 12. The method of any of the preceding clauses, further comprising identifying a fault and parameters associated with the fault in a fault section of a hybrid line system, 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.

[0062] 13. The method of either of the preceding clauses, wherein the first and second conditions are based on whether the fault is a single-phase-to-ground fault or a phase-to-phase fault, with the phase-to-phase fault being associated with a real function condition and the single-phase-to-ground fault being associated with an imaginary function condition.

[0063] 14. The method described in any of the preceding provisions, wherein the fault phase voltage phasor and fault phase current phasor are determined based on at least a portion of the type of fault associated with the fault.

[0064] 15. A hybrid line system comprising a first section having a first bus and a second section having a second bus, wherein a first set of voltage phasors and a first set of current phasors are calculated based on at least a portion of a set of measured voltage samples and a set of measured current samples associated with the first section, ABCD parameters associated with the hybrid line system are calculated based on at least a portion of input line parameters associated with the hybrid line system, a second set of voltage phasors and a second set of current phasors associated with the second section are calculated based on the first set of voltage phasors, the first set of current phasors, and at least a portion of the ABCD parameters, fault phase voltage phasors and fault phase current phasors are collected based on at least a portion of the second set of voltage phasors and a second set of current phasors, and faults and parameters associated with faults in the fault section of the hybrid line system are identified based on at least a portion of fault phase voltage phasors and fault phase current phasors.

[0065] 16. A hybrid line system as described in any of the preceding clauses, wherein the input line parameters include at least the line length of each section of the hybrid line system, the positive-sequence impedance per unit length of each section of the hybrid line system, the zero-sequence impedance per unit length of each section of the hybrid line system, the positive-sequence admittance per unit length of each section of the hybrid line system, and the zero-sequence admittance per unit length of each section of the hybrid line system.

[0066] 17. A hybrid line system as described in any of the preceding clauses, wherein a first set of voltage phasors and a first set of current phasors are calculated by applying a Fourier transform with attenuated DC (DC) rejection components to a set of measured voltage samples and a set of measured current samples.

[0067] 18. Identifying a fault within a fault 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 within the second section of the hybrid line system, for the hybrid line system described in any of the preceding clauses.

[0068] 19. For the hybrid line system described in any of the preceding clauses, 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, the phase-to-phase fault is associated with a real function condition, and the single-phase-to-ground fault is associated with an imaginary function condition.

[0069] 20. For the hybrid line system described in any of the preceding clauses, the fault phase voltage phasor and the fault phase current phasor are determined based on at least a part of the type of fault associated with the fault.

Explanation of Symbols

[0070] 100 Schematic Diagram 200 Schematic Diagram 300A Schematic Diagram 300B Schematic Diagram 302A Three-Phase Voltage 302B Three-Phase Voltage 302C Three-Phase Voltage 304A Three-Phase Current 304B Three-Phase Current 304C Three-Phase Current 306A Output U a (n), Voltage Phasor U a (n) 306B Output U b (n), Voltage Phasor U b (n) 306C Output U c (n), Voltage Phasor U c (n) 308A Output I a(n), current phasor I a (n) 308B Output I b (n), current phasor I b (n) 308C Output I c (n), current phasor I c (n) 310 Cosine filter COS F (n) 312 real components 314 Imaginary components 400 Schematic Diagram 402 First ABCD Algorithm Component 404 Second ABCD Algorithm Component 406 Third ABCD Algorithm Component 408 The fourth ABCD algorithm component 500 Schematic Diagram 502 Fault phasor acquisition component 600A schematic diagram 602 Source Impedance Calculation Component 604 Fault Section Identification and Parameter Acquisition Component 606 Fault S1 Section Identification Component 608 Fault SN-1 Section Identification Component 610 Final Logical Component 700 flowcharts

Claims

1. A method for determining the distance to a failure in a hybrid line system, Based on at least a portion of the measured voltage sample set (302A-C) and the measured current sample set (304A-C), a first set of voltage phasors (306A-C) and a first set of current phasors (308A-C) are calculated, Calculating the ABCD parameters associated with the hybrid line system based on at least some of the input line parameters associated with the hybrid line system, Calculating a second set of voltage phasors and a second set of current phasors based on the first set of voltage phasors (306A to C), the first set of current phasors (308A to C), and at least a portion of the ABCD parameters, Based on at least a portion of the second set of voltage phasors and the second set of current phasors, the fault phase voltage phasors and fault phase current phasors are collected. Based on at least a portion of the fault phase voltage phasor and the fault phase current phasor, identify the fault and the parameters associated with the fault in the fault section of the hybrid line system, Calculating the distance to the fault based on at least some of the parameters associated with the fault, A method that includes this.

2. The method according to claim 1, wherein the input line parameters include at least the line length of each section of the hybrid line system, the positive-sequence impedance per unit length of each section of the hybrid line system, the zero-sequence impedance per unit length of each section of the hybrid line system, the positive-sequence admittance per unit length of each section of the hybrid line system, and the zero-sequence admittance per unit length of each section of the hybrid line system.

3. The method according to claim 1, wherein the first set of voltage phasors (306A to C) and the first set of current phasors (308A to C) are calculated by applying a Fourier transform with attenuated DC rejection to the set of measured voltage samples (302A to C) and the set of measured current samples (304A to C).

4. Identifying the fault and the parameter associated with the fault in the fault section of the hybrid line system, It is determined that the first section of the aforementioned hybrid line system does not satisfy the first condition, It is determined that the second section of the aforementioned hybrid line system satisfies the second condition, It is determined that the fault is located within the second section of the hybrid line system, The method according to claim 1, further comprising:

5. The method according to claim 4, wherein the first and second conditions are based on whether the fault is a single-phase-to-ground fault or a phase-to-phase fault, the phase-to-phase fault is associated with a real function condition, and the single-phase-to-ground fault is associated with an imaginary function condition.

6. The method according to claim 1, wherein the fault phase voltage phasor and the fault phase current phasor are determined based on at least a portion of the type of fault associated with the fault.

7. The method according to claim 1, wherein the first set of voltage phasors (306A to C) and the first set of current phasors (308A to 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 a second bus of the hybrid line system.

9. It is a hybrid line system, A first section having the first bus, A second section having a second bus, Equipped with, A first set of voltage phasors (306A-C) and a first set of current phasors (308A-C) are calculated based on at least a portion of the set of measured voltage samples (302A-C) and the set of measured current samples (304A-C) associated with the first section. The ABCD parameters associated with the hybrid line system are calculated based on at least a portion of the input line parameters associated with the hybrid line system. A second set of voltage phasors and a second set of current phasors associated with the second section are calculated based on the first set of voltage phasors (306A-C), the first set of current phasors (308A-C), and at least a portion of the ABCD parameters. Fault phase voltage phasors and fault phase current phasors are collected based on at least a portion of the second set of voltage phasors and the second set of current phasors. Faults within the fault section of the hybrid line system and parameters associated with such faults are identified based on at least a portion of the fault phase voltage phasor and the fault phase current phasor. Hybrid line system.

10. The hybrid line system according to claim 9, wherein the input line parameters include at least the line length of each section of the hybrid line system, the positive-sequence impedance per unit length of each section of the hybrid line system, the zero-sequence impedance per unit length of each section of the hybrid line system, the positive-sequence admittance per unit length of each section of the hybrid line system, and the zero-sequence admittance per unit length of each section of the hybrid line system.

11. The hybrid line 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 rejection components to the set of measured voltage samples (302A-C) and the set of measured current samples (304A-C).

12. The identification of the fault and the parameter associated with the fault in the fault section of the hybrid line system is It is determined that the first section of the hybrid line system does not satisfy the first condition, It is determined that the second section of the hybrid line system satisfies the second condition, It is determined that the fault is located within the second section of the hybrid line system, The hybrid line system according to claim 9, further comprising:

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-to-ground fault or a phase-to-phase fault, the phase-to-phase fault is associated with a real function condition, and the single-phase-to-ground fault is associated with an imaginary function condition.

14. The hybrid line system according to claim 9, wherein the fault phase voltage phasor and the fault phase current phasor are determined based on at least a portion of the type of fault associated with the fault.

15. The hybrid line system according to claim 9, wherein the first set of voltage phasors (306A to C) and the first set of current phasors (308A to 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.

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