General traveling wave based protection and fault location for power systems

Abstract

Generalized traveling wave based protection and fault location for power systems. The technology described herein is generally directed to systems for power transmission system protection and fault location implemented in deployable devices such as at one or more nodes of a power transmission system. Aspects of the described technology can involve analyzing traveling waves corresponding to a fault on a power transmission system. Example aspects can include receiving data representing current and voltage components of a traveling wave, saving the data in a storage device for fault location determination of a fault, transforming the data into wavelet transform results via a wavelet transform, and using the wavelet transform results for protection of the power transmission system.

Description

Technical Field

[0001] This disclosure generally relates to power systems, and more particularly to traveling wave-based fault location and protection in power transmission platforms. Background Technology

[0002] Faults in a power system can occur on power transmission lines for a variety of reasons, including short circuits, lightning, damage to transmission line towers or utility poles, and damage to the transmission line itself (e.g., from ice, wind, fallen trees / branches). When a fault occurs in a power system, traveling waves are emitted from the location of the fault at very high speeds (close to the speed of light).

[0003] A fault at one location on a power transmission line can cause problems at other locations. Protection against such subsequent problems can be based on the detection of traveling waves, for example, tripping one or more relays before the fault cascades into a system-wide disturbance that causes widespread outages. Fault localization, which determines where the fault occurred, is also possible based on traveling wave detection, and this fault localization is valuable for protecting against isolated faults and for locating the problems that caused the fault to facilitate maintenance. Attached Figure Description

[0004] The techniques described herein are illustrated by way of example and are not limited to those shown in the accompanying drawings, in which the same reference numerals indicate similar elements, and wherein:

[0005] Figure 1 This is an example block diagram representation of a general scheme for a traveling wave-based protection and fault location device implemented based on one or more examples of the subject matter disclosed herein.

[0006] Figure 2 This is a block diagram representation of example details of a wave-based analyzer implemented based on one or more examples of the subject matter disclosed in this paper.

[0007] Figure 3 It is a block diagram of various example aspects representing fault phase identifiers, implemented based on one or more examples of the subject matter disclosed in this document.

[0008] Figure 4 It is a flowchart illustrating example operations related to the identification of execution failures, implemented according to one or more examples of the subject matter disclosed herein.

[0009] Figure 5 It is a block diagram representing various aspects of the wavelet transform, implemented based on one or more examples of the subject matter disclosed in this paper.

[0010] Figure 6It is a block diagram representing various example aspects of a fault detection component implemented based on one or more examples of the subject matter disclosed in this article.

[0011] Figure 7 It is a block diagram of a representation example polarization detection component implemented based on one or more examples of the subject matter disclosed in this article.

[0012] Figure 8 It is a representation of various exemplary aspects of traveling wave-based directional protection implemented according to one or more examples of the subject matter disclosed in this paper.

[0013] Figure 9 It is a representation of various exemplary aspects related to traveling wave-based distance protection, implemented based on one or more examples of the subject matter disclosed herein.

[0014] Figure 10 It is a representation of various exemplary aspects related to traveling wave-based boundary protection, implemented based on one or more examples of the subject matter disclosed in this paper.

[0015] Figure 11 It is a representation of various exemplary aspects related to traveling wave-based polarization comparison protection, implemented according to one or more examples of the subject matter disclosed herein.

[0016] Figure 12 It is a representation of various exemplary aspects related to traveling wave-based direction comparison protection, implemented based on one or more examples of the subject matter disclosed in this paper.

[0017] Figure 13 It is a representation of various exemplary aspects related to traveling wave-based directional distance / boundary cell protection, implemented according to one or more examples of the subject matter disclosed herein.

[0018] Figure 14 It is a representation of various exemplary aspects related to wave-based differential protection, implemented according to one or more examples of the subject matter disclosed herein.

[0019] Figure 15 It is a representation of various example aspects related to a traveling wave-based single-ended fault locator, implemented based on one or more examples of the subject matter disclosed in this paper.

[0020] Figure 16 It is a flowchart representation of various example operations related to traveling wave-based single-ended fault location, implemented according to one or more examples of the subject matter disclosed in this paper.

[0021] Figure 17 It is a flowchart representation of various example operations related to traveling wave-based two-end fault location, implemented according to one or more examples of the subject matter disclosed in this paper.

[0022] Figure 18 It is a representation of a multi-terminal system in which various example aspects of the disclosed subject matter can be implemented, including multi-terminal fault location.

[0023] Figure 19 It is a flowchart representation of various example operations related to locating fault sections by means of the arrival time of traveling waves in a multi-terminal system, implemented according to one or more examples of the subject matter disclosed in this article.

[0024] Figure 20 It is a flowchart representation of various aspects related to the analysis of traveling waves used for protection and fault location in power transmission systems, implemented based on one or more examples of the subject matter disclosed in this paper.

[0025] Figure 21 It is a block diagram representation of various components related to the use of traveling wavelets transformed from traveling waves for the protection of power transmission systems, implemented based on one or more examples of the subject matter disclosed herein.

[0026] Figure 22 It is a flowchart representation of various aspects related to using traveling waves for fault location, implemented based on one or more examples of the topics disclosed in this paper.

[0027] Figure 23 It is a schematic block diagram illustrating a suitable operating environment in which various example aspects of the disclosed subject matter can be implemented.

[0028] Figure 24 It is a schematic block diagram of an example computing environment in which various example aspects of the disclosed subject matter can be implemented.

[0029] Figure 25 A diagram depicts an example power grid environment in which various example aspects of the disclosed subject matter can be implemented. Detailed Implementation

[0030] The various aspects of the techniques described in this paper generally pertain to a system, such as one implemented in a device, that uses traveling waves for power transmission systems and fault location. In one implementation, the system includes fast traveling wave sampling for a traveling wave analyzer for ultra-high-speed (e.g., less than one millisecond) protection functions in a transmission relay platform. In another implementation, the system facilitates accurate traveling wave-based fault location (e.g., less than 120 meters if the sampling rate is on the order of 5 MHz).

[0031] As will be understood, general-purpose traveling wave-based fault locationrs and ultra-high-speed protection, including both dual-end and single-end fault location schemes, as well as all types of traveling wave-based ultra-high-speed protection, such as traveling wave-based distance, traveling wave-based direction, traveling wave-based polarization comparison protection, traveling wave differential, and traveling wave-based boundary protection.

[0032] It should be understood that any examples in this document are non-limiting. Therefore, the techniques described herein are not limited to any particular implementation, embodiment, aspect, concept, structure, function, or example described herein. Rather, any of the implementations, embodiments, aspects, concepts, structures, functions, or examples described herein are non-limiting, and the techniques can be used in various ways that generally provide benefits and advantages in power transmission systems and fault location concepts.

[0033] Figure 1 An example of a general-purpose traveling wave-based protection and fault location system 100 is depicted, much of which can be implemented, for example, in a traveling wave device that can be located at various locations in the power system (e.g., ...). Figure 18 (in Chinese). Usually, and as Figure 1 As shown in the diagram, bandpass filters 102 and 103 are used to extract transient traveling waves from the transmission line, which are provided by current transformer / current sensor 104 and voltage transformer / voltage sensor 105, respectively. Bandpass filters 102 and 103 remove the fundamental frequency and lower frequency components; if... Figure 1 If an analog bandpass filter is used as in the example, analog-to-digital (A / D) converters 106 and 107 are used to sample / digitize the extracted traveling wave.

[0034] More specifically, because the traveling wave is superimposed on the fundamental frequency, a bandpass filter is used to remove the fundamental frequency and lower frequency components for more accurate wave extraction, and to avoid aliasing that occurs before the corresponding A / D converter acquires the sample. The cutoff band of a bandpass filter is typically [1000Hz, fs / 2], where fs is the sampling frequency of the A / D converter; for example, if the sampling frequency is 1MHz, the bandpass filter's band is [1000, 500000]. Note that, for example, a third-order Butterworth bandpass filter can be used.

[0035] Therefore, after the traveling wave is extracted from the superimposed fundamental and lower frequency components by the analog bandpass filter, the transient traveling wave (of current and voltage) is sampled by A / D converters 106 and 107, which are controlled by a synchronization system 108 (in conjunction with a GPSPPS / IRIG component 109 (Global Positioning System Inter-range Instrumentation Group / Pulses Per Second)) to synchronize the sample time for use in two-end / multi-end fault location and / or traveling wave-based differential protection, as described herein. Note that the traveling wave samples (voltage and current) are buffered in memory 110. Once a fault / oscillation is detected on the power system, the resulting fault detection signal freezes the buffer, and a snapshot of the sample is sent to the offline fault location subsystem (e.g., via Ethernet connection 111, etc.).

[0036] like Figure 1 and Figure 2 As shown, the α-β transform is used to reflect various types of faults through a set of spatial vectors of the traveling wave. More specifically, to effectively respond to various types of faults, the α-β transform is used to convert three-phase voltage and current samples into α and β components, which are then combined into a complex spatial vector of the traveling wave. Alpha modes tend to represent the three-phase traveling wave corresponding to ground faults and can be calculated for phases A, B, and C, thus providing three alpha modes. Beta modes tend to represent the three-phase traveling wave corresponding to phase-to-phase faults and can be obtained for phase combinations, i.e., phases A and B, phase B and C, or phase C and A, thus providing three beta modes.

[0037] The inputs to the α-β transformation and spatial traveling wave formulation component 112 include the measured three-phase voltage and current; the outputs of component 112 include the vector (U) of the voltage traveling wave and the vector (I) of the current traveling wave I. The equations for expressing the spatial vectors are shown below.

[0038]

[0039] U = u α +j*u β (2)

[0040]

[0041] I = i α +j*i β (4)

[0042] Fault phase identification is performed by fault phase identification component 114. The fault phase is identified based on the space vectors of phases A, B, and C, respectively. More specifically, the inputs to fault phase identification component 114 include the three-phase currents, while the output of fault phase identification component 114 includes the digital signal D_ftPhs of the fault phase, where the following values ​​of D_ftPhs are shown, along with their meanings (e.g., via...). Figure 4 (Logical determination):

[0043] D_ftPhs = 0, indicating no fault or failure to identify;

[0044] D_ftPhs = 1, Phase A to ground fault;

[0045] D_ftPhs = 2, B-phase to ground fault;

[0046] D_ftPhs = 3, C-phase to ground fault;

[0047] D_ftPhs = 4, indicating a ground fault from phase B to phase C;

[0048] D_ftPhs = 5, indicating a ground fault from phase C to phase A;

[0049] D_ftPhs = 6, indicating a ground fault from phase A to phase B;

[0050] D_ftPhs = 7, fault from phase B to phase C;

[0051] D_ftPhs = 8, fault from phase C to phase A;

[0052] D_ftPhs = 9, fault from phase A to phase B;

[0053] D_ftPhs = 10, indicating an ABC phase fault or an ABC phase-to-ground fault.

[0054] Complex spatial vectors are constructed based on traveling waves of phases A, B, and C, respectively. The faulty phase can be identified by comparing the imaginary and real parts of the spatial vectors.

[0055] In one or more implementations, the components used for identifying fault phases based on traveling waves can be divided into three general parts, such as... Figure 3 As generally illustrated. The first part 330 includes α-β transformations based on phases A, B, and C, respectively. The second part 332 includes the absolute values ​​of the α-β transformations with an averaging filter added, for example, within a 0.2 ms time window. The third part 334 includes a fault phase identification procedure, as shown in the reference... Figure 4 The example operations are further described as follows.

[0056] The following equations show how to perform α-β transformation based on phases A, B, and C respectively, and how to calculate the zero-mode current (α-β-0):

[0057]

[0058] The absolute value and averaging filter component 332 takes the absolute value of α-β-0 and passes the absolute value through an averaging filter with a time window Tav, where, for example, Tav = 0.2 ms. The averaging filter is shown in Equation 9, where N = Tav / Ts, and Ts is the sampling period:

[0059]

[0060] The operation of the fault phase identification program is in Figure 4 This is shown in the flowchart. As you can see, I βmin and I αmax Calculated at operation 402, and then evaluated via operation 404. If I βmin Less than 0.05*I αmax Operations 406, 408, and 410 determine the value of D_FtPhs to be 0, 1, 2, or 3, depending on the required I. βmin respectively with I Aβ I Bβ and I Cβ A comparison.

[0061] Otherwise, operation 404 branches to operation 412, where I is determined. αmin and I βmax And it is evaluated at operation 414. For the sake of brevity, the various operations labeled 414-426 are not described separately, but can be seen as... Figure 4 What we see depends on I αmin to I Aα I Bα and I Cα The various possible results of D_ftPhs and / or I0 (as needed) result in D_ftPhs being equal to 0 or any one of 4-9.

[0062] Return to Figure 1 and 2 The traveling wave (TW) analyzer 116 is used by employing wavelet transform 222 ( Figure 2 Extract necessary information for various types of protection, such as travel wave-based distance, travel wave-based direction, travel wave-based differential, and travel wave-based boundary protection.

[0063] The protection described below is Figure 1It is represented by high-speed unit protection component 120 and high-speed non-unit protection component 122. Figure 1 The text also indicates and is described below for traveling wave-based fault location. A traveling wave offline analyzer 124 is coupled to a single-ended traveling wave fault location (TWFL) component 126, a double-ended traveling wave fault location (TWFL) component 127, and a multi-ended traveling wave fault location (TWFL) component 128.

[0064] To analyze waves, such as Figure 2 As shown, the inputs to the traveling wave analyzer 116 may include a voltage traveling wave vector U and a current vector I. The outputs of the traveling wave analyzer 116 include the following:

[0065] (1) A digital signal for fault detection identified as D_FD; if D_FD = 1, a fault / event has occurred;

[0066] (2) The first scale of the wavelet transform of the current traveling wave is denoted as I. WT_S1 The wavelet transform result is equivalent to the original signal passed through a bandpass filter with a frequency band of approximately [fs / 2, fs / 4], where fs is the sampling frequency. For example, if the sampling frequency is 1 MHz, the first scale of the wavelet transform includes a frequency band of [250 kHz, 500 kHz].

[0067] (3) Identified as U WT_S1 The first scale of the wavelet transform of the voltage traveling wave is given; the result of this wavelet transform is equal to the original signal passed through a bandpass filter with a frequency band of approximately [fs / 2, fs / 4], where fs is the sampling frequency. For example, if the sampling frequency is 1 MHz, the first scale of the wavelet transform includes a frequency band of [250 kHz, 500 kHz].

[0068] (4) Identified as I WT_S4 The fourth scale of the wavelet transform of the voltage traveling wave; the result of this wavelet transform is equal to the original signal passed through a bandpass filter with a frequency band of approximately [fs / 32, fs / 16], where fs is the sampling frequency. For example, if the sampling frequency is 1 MHz, the first scale of the wavelet transform includes a frequency band of [31.25 kHz, 62.5 kHz].

[0069] (5) Identified as U Scale_4The remaining portion of the voltage traveling wave after its four-scale wavelet transform is downsampled; the result of this wavelet transform is equivalent to the original signal passed through a low-pass filter with a frequency band of approximately [-fs / 32, fs / 32], where fs is the sampling frequency. For example, if the sampling frequency is 1 MHz, the first scale of the wavelet transform includes a frequency band of [-31.25 kHz, 31.25 kHz].

[0070] (6) The downsampled wavelet transform of the current traveling wave (the remainder after the fourth scale) is denoted as I. Scale_4 The wavelet transform result is equivalent to the original signal passed through a low-pass filter with a frequency band of approximately [-fs / 32, fs / 32], where fs is the sampling frequency. For example, if the sampling frequency is 1 MHz, the first scale of the wavelet transform includes a frequency band of [-31.25 kHz, 31.25 kHz].

[0071] (7) Identified as F S4 The positive traveling wave of the downsampled wavelet transform of voltage and current (the other four scales); that is, Where Zc represents surge impedance. Zc can be approximated; for example, it is set to 500 ohms in the primary stage for overhead transmission lines and 300 ohms for underground cables. Signal F S4 It is also sent to the remote end for use in wave-based differential protection at the remote end.

[0072] (8) Identified as B S4 The inverse traveling wave of the downsampled wavelet transform of voltage and current (the other four scales); that is, Zc represents surge impedance. Zc can be approximated, for example, 500 ohms in the primary winding for overhead transmission lines and 300 ohms for underground cables.

[0073] (9) Identified as D PI The digital signal polarized by the traveling wave of the current. D PI =0 indicates that polarization cannot be detected, or there is no fault; D PI =1 indicates positive polarization, and D PI =-1 indicates negative polarization. The polarization signal is also sent to the remote end to express polarization comparison protection in the remote module.

[0074] Therefore, as Figure 2As illustrated in the example implementation, four components are shown in the traveling wave real-time analyzer 116, including wavelet transform component 222, fault detection component 224 (FtDt), expression F and B (forward and backward) component 226, and polarization detection component 228.

[0075] Wavelet transform component 222 performs wavelet transform using two sets of coefficients. One set of coefficients includes scaling function coefficients denoted as p(n), and the other set includes wavelet coefficients denoted as q(n). For example, a 3rd-order Daubechies wavelet can be used.

[0076] Figure 5 The details of the wavelet transform are shown. In the first stage, the convolution of the input signal with coefficients p(n) and q(n) is obtained using the following equation (current is used as an example because voltage operates in the same way):

[0077]

[0078] The second stage performs downsampling of the convolution of p(n) at half the initial sampling rate, where downsampling is based on the following equation:

[0079] I Scale1 (k)=y1(2k) (12)

[0080] like Figure 5 As shown, the wavelet transform is repeated to obtain the second scale of the wavelet transform result. Second-scale scaling transformation result I Scale2 Similarly to and I Scale3 as well as and I Scale4 .

[0081] Example details of the fault detection component (FtDt) 224 are in Figure 6 The diagram shows that the magnitude of the current vector is represented by box 660 and is calculated using the following equation:

[0082]

[0083] The averaging filter 662 is applied to the amplitude; the window length of the averaging filter is N, for example, N can be set to 10 samples. The equation for the averaging filter 662 was previously shown in Equation 9, and is repeated below.

[0084]

[0085] Perform a comparison at box 664; when Greater than I set (For example, where I can be)set If the value is set to 0.05 per unit, the fault detection value FD equals 1; otherwise, FD equals 0. If FD equals 1, then D_FD equals 1; if FD equals 0, then the delay time T... set After that, T set =0.5ms, D_FD equals 0 (fallback delay). If FD equals 1, then D_FD_T equals 1, and T starts from FD=1. set After a certain time, D_FD_T = 0.

[0086] Figure 2 Box 226 represents the expression of forward and reverse traveling waves, which can be expressed by the following equations:

[0087] F S4 (n)=U Scate4 (n)+Z C I Scale4 (n) (14a)

[0088] B S4 =U Scale4 (n)-Z C I Scale4 (n) (14b)

[0089] Where Zc represents the surge impedance of the line as described above; for example, Zc can be approximated, such as 500 ohms in the primary for overhead transmission lines and 300 ohms for underground cables.

[0090] Polarization detection component 228 ( Figure 2 Other details are in Figure 7 As shown in the image. As you can see, I scale4 The sample is passed through an averaging filter 762 with a window length N; the averaging filter 762 can be the filter shown in Equation 9, and N can also be chosen as ten samples.

[0091] The real part 764 and imaginary part 765 of the output of the averaging filter 762 are passed through the corresponding quantization filters 766 and 767; the appropriate thresholds for quantization of +1 and -1 are +0.05pu (per unit) and -0.05pu, respectively. That is, if (e.g., I real If the value of ) is greater than +0.05, then the quantized output D_real = 1; otherwise, if the value is less than -0.05, then the quantized output D_real = -1; otherwise, if the value is in the range of -0.05 and 0.05, then D_real = 0.

[0092] As shown via boxes 768 and 769, the corresponding D_real and D_Imag values ​​are multiplied by D_FT_T (the signal from fault detection unit 224). Figure 2 and 6 As indicated by boxes 770 and 771, the corresponding results are held for a time Tset2 (e.g., 0.5 ms) to express D_Polar_Real and D_Polar_Imag, where D_Polar_Real = 1 if the real part of the current is positive, D_Polar_Real = -1 if the real part of the current is negative, and D_Polar_Real = 0 if the real part is less than 0.05 and greater than -0.05. The same applies to the imaginary part D_Polar_Imag.

[0093] Switching to wave-based protection, such as Figure 2 As seen in the diagram, the inputs of the traveling wave-based protection component 230 include at least some of the outputs of the traveling wave real-time analyzer unit 116. The following protection functions can be expressed:

[0094] (1) Based on the distance of the traveling wave (box 232), where the input is the first scale of the wavelet transform of the voltage and current traveling waves, and it can be expressed by comparing the time interval between the first and second effective waves with the propagation time from one end to the other.

[0095] (2) Boundary protection based on traveling wave (box 233), wherein the input is the first and fourth scales of the wavelet transform of the current traveling wave, and it can be expressed by comparing the magnitude of the first scale with that of the fourth scale.

[0096] (3) Based on the direction of the traveling wave (box 234), where the input is the fourth wavelet transform F of the forward and reverse traveling waves. S4 and B S4 The remaining downsampled values, and can be expressed by comparing the magnitudes of the reverse and forward traveling waves.

[0097] (4) Based on the direction comparison of traveling waves (box 235), and it can be determined by comparing the fault direction generated by the traveling waves at both ends of the line.

[0098] (5) Differential protection based on traveling wave (block 236), which can compare the differential wave W diff and bias wave W bias This can be expressed as the input being the reverse traveling wave at the local end and the forward traveling wave at the remote end.

[0099] (6) Polarization comparison protection based on traveling wave (block 237) can be expressed by comparing the polarization of the current traveling waves at both ends; if both ends are in the same polarization, it is determined to be an internal fault.

[0100] Figure 8 An example of implementing traveling wave-based directional protection is shown in box 234. Figure 2 Details related to this. Figure 8 In the middle, from wavelet transform ( Figure 2 The output of the fourth-scale forward and reverse traveling waves B S4 and F S4 It is sent to the corresponding absolute operator elements 880 and 881, where B S4 and F S4 The absolute value (of the ABS component) can be obtained through the following equation:

[0101]

[0102] As shown via boxes 882 and 883, B S4 and F S4 Used as the basis for comparison, where the results are as follows Figure 8 Use it as shown. Note that D_FT_T is the fault detection signal from the fault detection unit, as shown. Figure 2 and 6 As shown in the diagram. The reset delay specifies that if the input picks up, the output picks up; however, if the input drops, the output will drop after a certain delay following the input drop. The output (pickup) of DDB_DIR_FWD indicates that the fault is a forward fault, and the output (pickup) of DDB_DIR_RVS indicates that the fault is a reverse fault.

[0103] exist Figure 9 The diagram depicts distance protection for f-based traveling waves (box 232). Figure 2 The implementation is shown in the form of a schematic diagram. Figure 9 In the middle and high frequency traveling wave, the power P TWH The first scale U is obtained from the wavelet transform of voltage and current. WT_S1 and I WT_S1 To calculate. In the first operation (box 990), if P TWH If the value is less than -0.005pu, then D_TW_NEG = 1; otherwise, D_TW_NEG = 0. In the second operation (box 991), if P... TWH If the value is greater than 0.005pu, including the reset delay (box 993) for length h (the length of the wavelet coefficients), then D_TW_POS = 1; otherwise, D_TW_POS = 0.

[0104] As shown via blocks 994 (AND) and 996 (reset delay), D_TW_DIST is the result of an AND operation on D_TW_NEG and NOT D_TW_POS. That is, if D_TW_NEG = 1 and D_TW_POS = 0, then D_TW_DIST = 1; otherwise, D_TW_DIST = 0. The burst of D_TW_DIST is used for traveling wave time interval detection for distance protection based on traveling waves.

[0105] Block 998 measures the time T between the first two bursts of D_TW_DIST. TW12 . Block 999 discriminates internal faults for distance protection based on traveling waves. If T TW12 < Tset, it is determined as an internal fault and DDB_TW_DIST is issued. Tset is set to 0.95*(2L / c), where L is the length of the protected line and c is the speed of the traveling wave, which is approximately 2.97e+5 km / s for overhead transmission lines; for cables, this speed is calculated by the following equation:

[0106]

[0107] where L1 is the positive sequence inductance per unit length and C1 is the positive sequence shunt capacitance per unit length of the cable. This can be corrected online by charging the line.

[0108] Regarding traveling wave based boundary protection (block 233, Figure 2 ), the inputs to the boundary protection unit are the first scale and the fourth scale wavelet transforms of the current traveling wave, that is, I WT_S1 and I WT_S4 . Figure 10 A scheme for implementing traveling wave based boundary protection is shown in

[0109] In Figure 10 , the first scale wavelet transform I WT_S1 of the current enters the averaging filter 1062 within the time window of Tset; such a filter can be the same as the filter in the fault detection unit (Equation 9), where the time window N is equal to Tset / Ts. Note that, for example, Tset can be chosen as 0.2 ms and Ts is the sampling period, such as for a 1 MHz sampling rate, Ts is 1 μs. The absolute value E S1 (block 1064) can be calculated by Equation 15, where the absolute value is the square root of the sum of the squares of the real part and the imaginary part.

[0110] Also as Figure 10As shown, the fourth-scale wavelet transform IWT_S4 of the current is upsampled three times with two-step resolution (box 1060) so that the fourth-scale value has the same resolution as the first-scale value. Upsampling can be performed in two steps; the first step inserts zeros between samples, and the second step is a convolution operation with the coefficients p(n), as shown... Figure 5 As with wavelet transform. Again, it can be used to calculate E. S1 The same technique was used to calculate the absolute value E. S4 (Box 1065)

[0111] As indicated by box 1066, if E S1 >K*E S4 +E0, where K can be selected as 0.25 and E0 can be selected as 0.01pu, then the fault is identified as an internal fault, and the DDB_TW_BOUND output is high (value one). This output is related to D_FD_T (via... Figure 6 (Obtain) Perform AND operation to provide the obtained DDB_TW_BOUND value.

[0112] Figure 11 The diagram shows a method for implementing traveling wave-based polarization comparison protection (box 237). Figure 2 The scheme is as follows. The input to the traveling wave-based polarization comparison protection component 237 includes polarization signals (real and imaginary) from both the local and remote terminals. The local polarization signal needs to be delayed by the communication time delay (boxes 1110 and 1111) and multiplied by the remote polarization signal (boxes 1112 and 1113). If the result of the multiplication is positive, this indicates that the polarizations of the two terminals are the same; (a positive polarization signal will be +1, and a negative polarization signal will be -1).

[0113] Figure 12 The diagram shows the protection for direction comparison based on traveling wave (box 234). Figure 2 The solution is as follows: If the direction of the fault from both the local terminal and the remote terminal is determined to be in the positive direction, then it is an internal fault, and DDB_TW_DIR_COMP = 1.

[0114] Figure 13 A scheme for directional distance / boundary cell protection based on traveling wave is illustrated. The output of traveling wave-based boundary protection (using boundary protection as an example) or distance protection can be supervised by a directional signal from the directional element to express directional boundary protection (DDB_DIR_BOUND) or directional distance protection (DDB_DIR_DIST). When combined with a directional boundary / distance signal, this is expressed using an OR gate 1320 to represent the cell boundary / distance protection scheme.

[0115] Figure 14 A differential protection for traveling wave-based protection is shown (box 236, Figure 2 The scheme is as follows. The input of the traveling wave-based differential protection includes the fourth-scale scaling transformation B of the reverse traveling wave as described above. S4 And the fourth-scale scaling transformation of the positive traveling wave from the far end.

[0116] The first step, indicated by box 1440, is to delay the local traveling wave B by a local wave delay T. S4 With the received traveling wave F S4 alignment:

[0117] T = T comm -T prop (17)

[0118] Where T comm This is the communication delay from sending wave data from a remote terminal; this time can be resolved by time stamps on the sample (using synchronization devices such as GPS), and T prop This is the propagation time of the traveling wave from the remote terminal to the local terminal, which can be calculated using the following formula:

[0119]

[0120] Where L is the line length and c is the speed of the traveling wave, which can be set to 2.97e5 km / s, or calculated using Equation 16. This time can also be commissioned when the line is charging.

[0121] The second step, indicated by box 1442, involves differential traveling wave and bias traveling wave. Differential traveling wave w Diff and bias traveling wave w Bias It can be obtained from the following equation:

[0122]

[0123] Where N equals round(T / Ts), and Zc is the surge impedance; for overhead lines, Zc can be equal to 500 ohms on the primary side, while for cables, Zc... C Through Z C =sqrt(L1 / C1) to calculate.

[0124] In the third step, indicated by box 1444, the RMS value within the time window (Tset = 0.2ms) can be calculated using the following equation:

[0125]

[0126] Where N = round(Tset / Ts).

[0127] The fourth step, represented by box 1446, provides the differentiation between internal and external faults, namely, W. diff Is it greater than K times W? bias Add W0, where W0 can be equal to, for example, 0.1, and K can be set to 0.1-1.

[0128] Note that the final tripping logic needs to be synchronized with the fault phase identifier 114 ( Figure 1-4 The signal combination obtained.

[0129] Regarding aspects related to steering and fault location, the fault detection signal is handled by traveling wave analyzer 116 ( Figure 1 and 2 This data is generated and used to freeze traveling wave samples in memory 110 for high-accuracy offline fault location based on traveling wave data. More specifically, once a fault is detected, the memory, including the traveling wave samples, provides a snapshot of these persistent samples, which is sent to the fault location module, the central unit, and / or a third-party server to perform fault location operations. Figure 1 As shown, fault locator 125 may include single-end fault location 126, double-end fault location 127, and / or multi-end fault location 128. The output from fault locator 125 (e.g., any one of 125-127) may include fault segment and fault distance.

[0130] For single-ended fault location, the wavelet transform I of the current WT_S1 The active power P of the high-frequency traveling wave TWH It is fed into the single-ended fault locator 126. Figure 15 A scheme for a single-ended fault locator based on traveling waves is shown.

[0131] exist Figure 15 In the middle, find I in box 1550. WT_S1 The local maximum of the absolute value (modulus). Box 1552 detects the direction of the local maximum. If P TWH If the value is less than a negative threshold, such as -0.005, the maximum value is retained; otherwise, it is discarded. One or more local maxima with a positive direction are sent to the fault location procedure 1554 to calculate the fault distance.

[0132] Fault location program logic 1554 in Figure 16The process is as follows: As can be seen, operation 1602 evaluates the first maximum value, and if the first maximum value exists, operation 1604 records the time stamp T1. Similarly, operation 1606 evaluates the second maximum value, and if the second maximum value exists, operation 1608 records the time stamp T2; furthermore, operation 1610 records the maximum value as Im1. Operation 1612 evaluates the third maximum value, and if the third maximum value exists, operation 1614 records the time stamp T3, and operation 1616 records the maximum value as Im2.

[0133] Using the values ​​obtained via operations 1604, 1608, and 1610 and / or operations 1614 and 1616, X is generated via the logic shown in operations 1618, 1620, or 1622, where the distance is based on T1 and T2 or T3. Note that c is the velocity of the traveling wave.

[0134] For two-end fault location, the recorded sample or detected arrival time is sent to the central unit. Fault locator, such as two-end fault locator component 127 ( Figure 1 It can be deployed in a central unit. Figure 17 The diagram illustrates the process used to accurately locate faults.

[0135] Figure 17 Operation 1702 inputs the initial parameters of the line length L and the traveling wave velocity c0; this velocity can be evaluated by the line parameters of series impedance and parallel admittance, or given by approximation, such as 2.95E+5km / s for overhead transmission lines.

[0136]

[0137] Where z1 is the series impedance per kilometer of line, y1 is the parallel admittance per kilometer of line, and f0 = 50 or 60 Hz.

[0138] If the line is charging as assessed by Operation 1704, i.e., only one terminal breaker is closed, the speed of the traveling wave can be modified (Operation 1708) by detecting the arrival times at both terminals (Operation 1706):

[0139]

[0140] Where TA is the time it takes for the traveling wave to reach the remote terminal (where the circuit breaker is not closed), and TB is the time it takes for the wave to reach the terminal where the circuit breaker is closed.

[0141] If a fault occurs on the line, the traveling wave arrival time is detected as TA at operation 1708 in substation A, and as TB in substation B. The fault distance to substation A can be determined by operation 1712, corresponding to the following equation:

[0142]

[0143] After locating the fault, if possible, request feedback from maintenance personnel regarding the actual fault distance (Operation 1714) to calibrate the parameters L and c0, thereby improving the accuracy of fault location. The parameters can be calibrated using the following formulas (Operations 1716 and 1718):

[0144] Error = x real -x

[0145] L = L + 0.002 * Error

[0146] c0 = c0 + 3000 * Error * (T A -T B )

[0147] The fault distance can be recalculated, and steps 1716 and 1718 can be repeated as needed, for example, until the error is less than 150 meters. The correction parameters for L and c0 are recorded for use in the next fault location.

[0148] Figure 18 A multi-terminal system is shown, for which multi-terminal fault location can be performed (box 128). Figure 1 For example, consider a failure occurring in a multi-terminal system where traveling wave devices / nodes TWD_A-TWD_H are deployed on each node.

[0149] Figure 19 The diagram illustrates the process of fault location and fault segment identification (fault segment location) for the example above (for nodes AH corresponding to 1 to 8). Before fault segment location occurs, the traveling wave topology matrix is ​​expressed by the following sub-process: If node i (i = A, B, ..., H) is directly connected to node j (j = A, B, ..., H), then the i-th row and j-th column of the matrix is ​​T. Lij It is the propagation time from node i to j: Where L ij c is the length of the segment between i and j. ij This is the traveling wave velocity propagating in this segment (it may differ from the velocity in different segments because the conductors may be different). If node i is not directly connected to node j, then the i-th row and j-th column of the matrix is ​​zero.

[0150]

[0151] Operations 1902-1918 measure the traveling wave at each node (if it is a current measurement, the current in any branch connected to the node can be measured at that node, thus eliminating the need to deploy current measurements for every branch connected to the node). In this example, the primary arrival time of the traveling wave is determined by iterating through the i and j corresponding to node AH. For example, if a fault occurs in segment BD, each traveling wave device (TWD) can measure the traveling wave and obtain the arrival times of the primary traveling wave: TArriv_A, TArriv_B, TArriv_C, ..., TArriv_H.

[0152] Operations 1922 and 1924 (if necessary) locate the faulty segment. Typically, at operation 1922, if the arrival time difference is less than the propagation time along a given segment, the fault is in that segment. If the fault is not in any segment—that is, there is no segment for which its arrival time difference is less than the propagation time along that segment—the fault is located at the node with the earliest arrival time (operation 1924). Once the faulty segment is identified, the fault distance can be determined using the two-end method already presented above.

[0153] One or more aspects, such as those implemented in example operations of a method (e.g., executed by a system including a processor), Figure 20 The code represents the analysis (operation 2002) of a traveling wave corresponding to a fault on the power transmission system. Operation 2004 represents receiving data representing the current and voltage components of the traveling wave. Operation 2006 represents storing the data in a storage device for fault location determination. Operation 2008 represents transforming the data (including transformation via wavelet transform) into a wavelet transform result. Operation 2010 represents using the wavelet transform result for protection of the power transmission system.

[0154] The process may include receiving analog current and voltage information from corresponding current and voltage sensors coupled to the power transmission system, filtering the analog current and voltage information via bandpass filtering to obtain traveling wave information including analog current and voltage information, and digitizing the traveling wave information into data representing the current and voltage components of the traveling wave.

[0155] Transforming the data, including transforming it via wavelet transform, can include transforming the data into a spatial vector including current vector and voltage vector via α-β transform, and then performing wavelet transform on the current vector and voltage vector to obtain the wavelet transform result.

[0156] Applying wavelet transform results to the protection of power transmission systems can include using a first scale of the wavelet transform results of voltage and current traveling waves for traveling wave-based distance protection. Applying wavelet transform results to the protection of power transmission systems can include using a first and fourth scale of the wavelet transform results of current traveling waves for traveling wave-based boundary protection. Applying wavelet transform results to the protection of power transmission systems can include using downsampled values ​​corresponding to forward and reverse traveling waves to determine traveling wave direction data. Applying wavelet transform results to the protection of power transmission systems can include using the traveling wave direction data for direction comparison-based protection, which compares the fault direction generated by the traveling wave at the end of the power transmission system.

[0157] Applying wavelet transform results to the protection of power transmission systems can include multiplying the fourth scale of the wavelet transform results based on voltage traveling waves and the fourth scale of the wavelet transform results based on current traveling waves by the system surge impedance value to express forward and reverse traveling wave information, using the forward and reverse traveling wave information to obtain differential traveling wave information and bias traveling wave information, and using the differential traveling wave information and bias traveling wave information for traveling wave-based differential protection.

[0158] Applying wavelet transform results to the protection of power transmission systems can include comparing the polarization of current traveling waves at both ends of the power transmission system to perform polarization comparison protection. Applying wavelet transform results to the protection of power transmission systems can also include performing unit-based protection to output a trip signal within defined boundaries. Applying wavelet transform results to the protection of power transmission systems can further include performing non-unit-based protection to output a trip signal.

[0159] Storing data in a storage device for fault location determination may include providing time-based snapshot data to a single-ended traveling wave fault locator.

[0160] Storing data in a storage device for fault location determination may include providing time-based snapshot data to a two-end traveling wave fault locator. Aspects may include obtaining the actual fault distance value and using the actual fault distance value to improve fault location accuracy.

[0161] Storing data in a storage device for fault location determination may include providing time-based snapshot data to a multi-terminal traveling wave fault locator. Aspects may include the multi-terminal traveling wave fault locator iterating over a set of nodes corresponding to traveling wave devices deployed at multiple ends to locate the fault segment.

[0162] One or more example aspects in Figure 21The text indicates that this corresponds to a system including a traveling wave device 2102 configured to analyze traveling wave data representing traveling waves corresponding to faults on a power transmission system. The traveling wave device 2102 may include a processor 2104 and a wavelet transform component 2106, which transforms the traveling wave data into a wavelet transform result via the processor 2104. The traveling wave device 2102 may also include a protection component 2108 that uses the wavelet transform result to output a trip signal for power transmission system protection. This protection component may include a traveling wave-based distance protection component 2110, a traveling wave-based boundary protection component 2112, a traveling wave-based differential protection component 2114, and a traveling wave-based polarization-based protection component 2116.

[0163] The traveling wave device can be further configured to store a digital representation of the traveling wave data in a storage device for offline fault location determination.

[0164] exist Figure 22 The term "operation" refers to one or more aspects implemented in a machine-readable storage medium, including executable instructions that, when executed by a processor, facilitate the execution of operations. Example operations include operation 2202, which represents receiving analog current and voltage information from corresponding current and voltage sensors coupled to a power transmission system. Operation 2204 represents filtering the analog current and voltage information via a bandpass filter to obtain traveling wave information including the analog current and voltage information. Operation 2206 represents digitizing the traveling wave information into data representing the current and voltage components of the traveling wave. Operation 2208 represents storing the data in a storage device for fault location determination.

[0165] Further operations may include transforming the data into a spatial vector including current and voltage vectors via α-β transform, transforming the data into a wavelet transform result via wavelet transform, and using the wavelet transform result for protection of the power transmission system.

[0166] As can be seen, the techniques described in this paper facilitate a system that enables various types of traveling wave-based protection against a wide range of fault types. The techniques described in this paper also facilitate accurate fault location.

[0167] In order to provide context for the various aspects of the disclosed topic, Figure 23The following discussion is intended to provide a brief, general description of suitable environments in which various aspects of the disclosed subject matter can be implemented. While the subject matter has been described above in the general context of computer-executable instructions of a computer program running on one or more computers, those skilled in the art will recognize that the disclosed subject matter can also be implemented in conjunction with other program modules. Typically, program modules include routines, programs, components, data structures, etc., that perform specific tasks and / or implement specific abstract data types.

[0168] In this specification, terms such as “storage,” “storage device,” “data storage,” “data storage device,” “database,” and virtually any other information storage component relating to the operation and function of the component refer to a “memory component” or an entity implemented in “memory” or a component that includes memory. It should be noted that the memory component described herein may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory, as illustrated and not limited to: volatile memory 2320 (see below), non-volatile memory 2322 (see below), disk storage device 2324 (see below), and memory storage device 2346 (see below). Furthermore, non-volatile memory may be included in read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, or flash memory. Volatile memory may include random access memory that acts as an external cache memory. By way of illustration and not limitation, random access memory is available in a variety of forms, such as synchronous random access memory, dynamic random access memory, synchronous dynamic random access memory, dual data rate synchronous dynamic random access memory, enhanced synchronous dynamic random access memory, Synchlink dynamic random access memory, and direct Rambus random access memory. Furthermore, the memory components disclosed in the systems or methods herein are intended to include, but are not limited to, these and any other suitable types of memory.

[0169] Furthermore, it should be noted that the disclosed subject matter can be implemented using other computer system configurations, including single-processor or multi-processor computer systems, small computing devices, mainframe computers, personal computers, handheld computing devices (e.g., personal digital assistants, telephones, watches, tablets, netbooks, etc.), microprocessor-based or programmable consumer or industrial electronic devices, etc. The described aspects can also be implemented in a distributed computing environment, where tasks are performed by remote processing devices linked via a communication network; however, some (if not all) aspects of this disclosure can be implemented on a standalone computer. In a distributed computing environment, program modules can reside on both local and remote memory storage devices.

[0170] Figure 23 A block diagram of a computing system 2300 operable to perform the disclosed systems and methods according to an embodiment is illustrated. The computer 2312 includes a processing unit 2314, a system memory 2316, and a system bus 2318. The system bus 2318 couples system components to the processing unit 2314, including but not limited to the system memory 2316. The processing unit 2314 can be any processor from a variety of available processors. Dual microprocessors and other multiprocessor architectures can also be used as the processing unit 2314.

[0171] The system bus 2318 can be any of several types of bus architectures, including memory bus or memory controller, peripheral bus or external bus, and / or local bus using any of the various available bus architectures, including but not limited to industry standard architecture, microchannel architecture, extended industry standard architecture, smart drive electronics, video electronics standards association local bus, peripheral component interconnect, card bus, universal serial bus, advanced graphics port, PC Memory Card International Association bus, FireWire (IEEE 2494), and small computer system interface.

[0172] System memory 2316 may include volatile memory 2320 and non-volatile memory 2322. A basic input / output system may be stored in the non-volatile memory 2322, which includes routines for transferring information between components within the computer 2312, such as during startup. By way of illustration and not limitation, non-volatile memory 2322 may include read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, or flash memory. Volatile memory 2320 includes read-only memory that acts as an external cache memory. By way of illustration and not limitation, read-only memory is available in various forms, such as synchronous random access memory, dynamic read-only memory, synchronous dynamic read-only memory, dual data rate synchronous dynamic read-only memory, enhanced synchronous dynamic read-only memory, Synchlink dynamic read-only memory, Rambus direct read-only memory, direct Rambus dynamic read-only memory, and Rambus dynamic read-only memory.

[0173] Computer 2312 may also include removable / non-removable, volatile / non-volatile computer storage media. Figure 23For example, a disk storage device 2324 is illustrated. Disk storage device 2324 includes, but is not limited to, devices such as disk drives, floppy disk drives, tape drives, flash memory cards, or memory sticks. Furthermore, disk storage device 2324 may include storage media, alone or in combination with other storage media, including, but not limited to, optical disc drives, such as compact disc read-only memory devices, compact disc recordable drives, compact disc rewritable drives, or digital universal disk read-only memory. To facilitate connection of disk storage device 2324 to system bus 2318, removable or non-removable interfaces, such as interface 2326, are typically used.

[0174] Computing devices typically include a variety of media, which may include computer-readable storage media or communication media, and these two terms are used differently from each other in this document.

[0175] Computer-readable storage media can be any available storage medium that can be accessed by a computer, and includes both volatile and non-volatile media, removable and non-removable media. By way of example and not limitation, computer-readable storage media can be implemented using any method or technique for storing information such as computer-readable instructions, program modules, structured data, or unstructured data. Computer-readable storage media can include, but is not limited to, read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, flash memory or other storage technologies, compact disc read-only memory, digital universal disk or other optical disc storage devices, magnetic tape cassettes, magnetic tape, disk storage devices or other magnetic storage devices, or other tangible media that can be used to store desired information. In this regard, the term "tangible" as used herein to describe a storage device, memory, or computer-readable medium is to be understood to exclude only the propagation of intangible signals as a modifier, and does not waive coverage of all standard storage devices, memories, or computer-readable media that not only propagate intangible signals themselves. In one aspect, tangible media may include non-transitory media, wherein the term "non-transitory" as used herein, as can be applied to storage devices, memories, or computer-readable media, is to be understood to exclude only the propagation of transient signals as a modifier, and does not relinquish coverage of all standard storage devices, memories, or computer-readable media that do not only propagate transient signals themselves. Computer-readable storage media can be accessed, for example, by one or more local or remote computing devices via access requests, queries, or other data retrieval protocols for various operations concerning information stored on the medium.

[0176] Communication media typically implement computer-readable instructions, data structures, program modules, or other structured or unstructured data in data signals, such as modulated data signals, carrier waves, or other transmission mechanisms, and include any information delivery or transmission medium. The term "modulated data signal" or signal refers to a signal whose characteristics are set or altered in such a way as to encode information in one or more signals. By way of example and not limitation, communication media include wired media (such as wired networks or direct wired connections) and wireless media (such as acoustic, RF, infrared, and other wireless media).

[0177] It can be noted that, Figure 23 Software that acts as an intermediary between the user and the computer resources described in the appropriate operating environment 2300 is described. Such software includes an operating system 2328. The operating system 2328, which can be stored on a disk storage device 2324, is used to control and allocate the resources of the computer system 2312. System application 2330 utilizes the operating system 2328 for resource management through program modules 2332 and program data 2334 stored in system memory 2316 or on disk storage device 2324. It should be noted that the disclosed subject matter can be implemented using various operating systems or combinations of operating systems.

[0178] Users can input commands or information into computer 2312 through one or more input devices 2336. As an example, the user interface can be implemented in a touch-sensitive display panel that allows users to interact with computer 2312. Input devices 2336 include, but are not limited to, pointing devices such as mice, trackballs, styluses, touchpads, keyboards, microphones, joysticks, gamepads, satellite dishes, scanners, TV tuner cards, digital cameras, digital camcorders, webcams, cellular phones, smartphones, tablets, etc. These and other input devices are connected to processing unit 2314 via system bus 2318 through one or more interface ports 2338. The one or more interface ports 2338 include, for example, serial ports, parallel ports, game ports, universal serial buses, infrared ports, Bluetooth ports, IP ports, or logical ports associated with wireless services. Output devices 2340 use some of the same type of ports as the one or more input devices 2336.

[0179] Therefore, for example, a Universal Serial Bus port can be used to provide input to computer 2312 and output information from computer 2312 to output device 2340. Output adapter 2342 is provided to illustrate that, in addition to output devices 2340 using special adapters, there are other output devices 2340, such as monitors, speakers, and printers. By way of illustration and not limitation, output adapter 2342 includes video and sound cards that provide a means of connection between output devices 2340 and system bus 2318. It should be noted that other devices and / or systems of devices provide both input and output capabilities, such as one or more remote computers 2344.

[0180] Computer 2312 can operate in a networked environment using a logical connection to one or more remote computers (such as one or more remote computers 2344). The one or more remote computers 2344 can be personal computers, servers, routers, network PCs, cloud storage devices, cloud services, workstations, microprocessor-based devices, peer-to-peer devices, or other public network nodes, and typically include many or all of the elements described relative to computer 2312.

[0181] For simplicity, only the memory storage device 2346 is illustrated for the remote computer(s) 2344(s). The remote computer(s) 2344(s) are logically connected to computer 2312 via network interface 2348 and then physically connected via communication connection 2350. Network interface 2348 includes wired and / or wireless communication networks, such as local area networks (LANs) and wide area networks (WANs). LAN technologies include fiber optic distributed data interfaces (FDI), copper distributed data interfaces (CDI), Ethernet, token ring, etc. WAN technologies include, but are not limited to, point-to-point links, circuit-switched networks (such as Integrated Services Digital Networks and variants thereof), packet-switched networks, and digital subscriber lines. As noted below, wireless technologies may be used in addition to or instead of the foregoing.

[0182] One or more communication connections 2350 refer to the hardware / software used to connect network interface 2348 to bus 2318. Although communication connection 2350 is shown inside computer 2312 for clarity, it can also be outside computer 2312. The hardware / software used to connect to network interface 2348 may include, for example, internal and external technologies such as modems, including conventional telephone-grade modems, cable modems and digital subscriber line modems, integrated services digital network adapters and Ethernet cards.

[0183] Figure 24This is a schematic block diagram of a sample computing environment 2400 with which the subject matter of this disclosure can interact. System 2400 includes one or more clients 2410. The clients 2410(s) can be hardware and / or software (e.g., threads, processes, computing devices). System 2400 also includes one or more servers 2430. Thus, among other models, system 2400 can also correspond to a two-tier client-server model or a multi-tier model (e.g., client, middleware server, data server). The servers 2430(s) can also be hardware and / or software (e.g., threads, processes, computing devices). For example, by employing this disclosure, server 2430 can accommodate threads to perform transformations. One possible communication between client 2410 and server 2430 can be in the form of data packets transferred between two or more computer processes.

[0184] System 2400 includes a communication framework 2450 that can be used to facilitate communication between one or more clients 2410 and one or more servers 2430. One or more clients 2410 are operably connected to one or more client data storage devices 2420, which can be used to store information locally on the clients 2410. Similarly, one or more servers 2430 are operably connected to one or more server data storage devices 2440, which can be used to store information locally on the servers 2430.

[0185] Figure 25 A diagram depicting an example power grid environment 2500 is provided, in which various aspects of the disclosed subject matter can be implemented. It should be understood that this diagram and the associated disclosure are presented as non-limiting examples to facilitate a general understanding of one or more aspects of the disclosed subject matter in conjunction with hypothetical power grid assets. Furthermore, although sample values ​​and assets are illustrated for context, these same sample values ​​and assets are non-limiting and should not be considered as any reduction in the scope. Figure 25 The assets can be allocated to either the transmission network portion (upper part of the diagram) or the distribution network portion (lower part of the diagram), as is typical in many power grids worldwide. Transmission systems are typically associated with the transmission of very high AC voltages or even DC power. Transmission systems are often presented in the context of delivering high power to regional distribution networks managed by distribution network entities.

[0186] Conventional distribution networks, as disclosed in this article, typically have a flat control structure, where control is centralized in a distribution control center (DCC). In contrast, such as Figure 25As shown, a non-flat control topography may be employed according to the subject matter disclosed herein. In this non-limiting example, a three-layer power distribution control system assembly is illustrated. A top-level (e.g., upper-level) control node 2510 (also referred to as TOP 2510) (e.g., including a top-level DNNC component and a top-level PSBC) may be communicatively coupled to primary-level control nodes (e.g., 2520 to 2536), which may include primary-level DNNC components and primary-level PSBCs. Figure 25 The diagram illustrates the basic tree structure topology.

[0187] In one aspect, two intermediate layer control nodes 2520 (also referred to as MID 2520) and 2521 (also referred to as MID 2521) can be logically positioned between a bottom-layer (e.g., lower-level) control node and a top-layer control node 2510. Furthermore, several bottom-layer control nodes, such as bottom-layer control nodes 2530 to 2536 (also referred to as BOT 2530 to BOT 2536), can be associated with various edge assets. For example, bottom-layer control node 2530 can be associated with a city power plant, and bottom-layer control node 2531 can be associated with a small group of industrial customers. Bottom-layer control nodes 2530 and 2531 can be logically connected to top-layer control node 2510 via intermediate layer control node 2520. In this way, data and rules can bubble up (e.g., be transmitted upwards within a hierarchy) or push down (e.g., be transmitted downwards within a hierarchy) through this communication path. Bidirectional communication and closed-loop control at each layer (e.g., top, intermediate, and bottom layers) can facilitate improved distribution network performance. For example, in the event that an industrial customer associated with the lower control node 2531 requires additional power, the control signal from the intermediate control node 2520 can obtain more power from the city power plant through the lower control node 2530, without directly involving the top control node 2510 or draining energy from the illustrated solar or wind farm.

[0188] Similarly, intermediate layer control node 2521 can be associated with lower layer control nodes 2532 to 2536. For example, lower layer control node 2533 can be logically associated with multiple transformers serving as part of a city network. Furthermore, for example, lower layer control node 2534 can be associated with a single transformer that is part of a rural network. Additionally, for example, at lower layer control node 2532, the control node can be associated with a single consumer such as a farm. The control node can also be associated with distributed generation, for example, lower layer control node 2535 is associated with a solar power plant, and lower layer control node 2536 is associated with a wind power plant. Thus, bidirectional communication between top layer control node 2510 and lower layer control nodes 2532 to 2536 can be performed through intermediate layer control node 2521. Thus, the rules propagated for intermediate layer control node 2520 and its associated sub-control nodes can differ from the rules propagated for intermediate layer control node 2521 and its associated sub-control nodes. Furthermore, independent closed-loop control can be affected, for example, at the underlying control node 2534 and the associated rural customers, without affecting the underlying control node 2533 and the associated urban network.

[0189] It should be noted that the aspects or features of this disclosure can be utilized in virtually any wireless telecommunications or radio technology, such as Wi-Fi; Bluetooth; Global Microwave Access Interoperability (WiMAX); Enhanced General Packet Radio Service (Enhanced GPRS); 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE); 3rd Generation Partnership Project 2 (3GPP2) Ultra Mobile Broadband (UMB); 3GPP Universal Mobile Telecommunications System (UMTS); High-Speed ​​Packet Access (HSPA); High-Speed ​​Downlink Packet Access (HSDPA); High-Speed ​​Uplink Packet Access (HSUPA); GSM (Global System for Mobile Communications) EDGE (Enhanced Data Rate Evolution of GSM) Radio Access Network (GERAN); UMTS Terrestrial Radio Access Network (UTRAN); LTE Advanced (LTE-A), etc. Furthermore, some or all of the aspects described herein can be utilized in conventional telecommunications technologies (e.g., GSM). Additionally, mobile and non-mobile networks (e.g., the Internet, data service networks such as Internet Protocol Television (IPTV), etc.) can utilize the aspects or features described herein.

[0190] While the subject matter has been described above in the general context of computer-executable instructions of a computer program running on one or more computers, those skilled in the art will recognize that this disclosure may also be implemented, or can be implemented in combination with, other program modules. Typically, program modules include routines, programs, components, data structures, etc., that perform specific tasks and / or implement specific abstract data types. Furthermore, those skilled in the art will understand that the methods of the present invention can be implemented using other computer system configurations, including single-processor or multi-processor computer systems, small computing devices, mainframe computers, personal computers, handheld computing devices (e.g., PDAs, telephones), microprocessor-based or programmable consumer or industrial electronic devices, etc. The described aspects can also be implemented in a distributed computing environment, where tasks are performed by remote processing devices linked via a communication network. However, some (if not all) aspects of this disclosure can be implemented on a standalone computer. In a distributed computing environment, program modules can reside on both local and remote memory storage devices.

[0191] The above description of the illustrative embodiments of this disclosure, including the content described in the abstract, is not intended to be exhaustive or to limit the disclosed embodiments to the precise form disclosed. Although specific embodiments and examples have been described herein for illustrative purposes, various modifications are possible and are considered to be within the scope of such embodiments and examples, as will be recognized by those skilled in the art.

[0192] In this regard, although the disclosed subject matter has been described in conjunction with various embodiments and corresponding drawings, it will be understood that other similar embodiments may be used where applicable, or modifications and additions may be made to the described embodiments to perform the same, similar, alternative, or substitute functions of the disclosed subject matter without departing from it. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but should be interpreted in breadth and scope according to the appended claims.

[0193] As used herein, the term "processor" can refer to virtually any computing processing unit or device, including but not limited to single-core processors; single-core processors with software multithreading capabilities; multi-core processors; multi-core processors with software multithreading capabilities; multi-core processors with hardware multithreading technology; parallel platforms; and parallel platforms with distributed shared memory. Furthermore, "processor" can refer to integrated circuits, application-specific integrated circuits (ASICs), digital signal processors, field-programmable gate arrays (FPGAs), programmable logic controllers (PLCs), complex programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Processors can utilize nanoscale architectures, such as, but not limited to, molecular and quantum-dot-based transistors, switches, and gates, to optimize space utilization or enhance the performance of user devices. Processors can also be implemented as a combination of computing processing units.

[0194] As used herein, the terms “component,” “system,” “platform,” “layer,” “selector,” “interface,” etc., are intended to refer to a computer-related entity or an entity associated with an operating device having one or more specific functions, wherein the entity may be hardware, a combination of hardware and software, software, or software in execution. As an example, a component may be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an executing thread, a program, and / or a computer. By way of illustration and not limitation, both an application running on a server and the server itself can be components. One or more components may reside in a process and / or an executing thread, and components may reside on a single computer and / or be distributed across two or more computers. Furthermore, these components may be executable from various computer-readable media on which various data structures are stored. The components may communicate via local and / or remote processes, such as according to signals having one or more data packets (e.g., data from one component interacts with another component in a local system, a distributed system, and / or interacts with other systems across a network such as the Internet via the signal). As another example, a component can be a device having specific functions provided by mechanical parts operated by electrical or electronic circuitry, operated by a software or firmware application executed by a processor, wherein the processor may be internal or external to the device and execute at least a portion of the software or firmware application. As yet another example, a component can be a device having specific functions provided by electronic components without mechanical parts, the electronic components including a processor to execute software or firmware that at least partially endows the electronic components with functionality.

[0195] Furthermore, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless otherwise specified or clear from the context, "X adopts A or B" is intended to mean either of the naturally inclusive permutations. That is, if X adopts A; X adopts B; or X adopts both A and B, then "X adopts A or B" is satisfied in any of the foregoing cases. Additionally, the articles "a" and "an" as used in this specification and figures should generally be interpreted as meaning "one or more," unless otherwise specified or clear from the context to refer to the singular form.

[0196] Furthermore, the term "including" is intended to be used as an open or inclusive term, not a closed or exclusive one. Unless explicitly used otherwise, the term "including" may be replaced by the term "containing" and will be considered to have a similar scope. As an example, "a basket of fruits including apples" will be considered to have the same breadth of scope as "a basket of fruits containing apples".

[0197] Furthermore, unless the context guarantees a specific distinction between one or more of the terms, the terms “user,” “subscriber,” “customer,” “operator,” “switchman,” “consumer,” “prosumer,” “agent,” etc., are used interchangeably throughout this specification. It should be understood that such terms may refer to human entities or automated components that can provide simulated visual, voice recognition, etc. (e.g., supported by artificial intelligence, such as the ability to reason based on complex mathematical formalisms).

[0198] The above description includes examples illustrating the systems and methods of the disclosed subject matter. It is, of course, impossible to describe every combination of components or methods herein. Those skilled in the art will recognize that many further combinations and arrangements of the claimed subject matter are possible. Furthermore, with regard to the terms “comprising,” “having,” “possessing,” etc., used in the detailed description, claims, appendices, and drawings, such terms are intended to be inclusive in a manner similar to the term “including,” as interpreted when “including” is used as a transitional word in a claim.

[0199] While the invention is readily adaptable to various modifications and alternative constructions, certain illustrative implementations are shown in the accompanying drawings and have been described in detail above. However, it should be understood that the invention is not intended to be limited to the specific forms disclosed, but rather, all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention are intended to cover.

[0200] In addition to the various implementations described herein, it is to be understood that other similar implementations may be used, or modifications and additions may be made to the described implementation(s) to perform the same or equivalent functions of the corresponding implementation(s) without deviation. Therefore, the invention is not limited to any single implementation, but is to be interpreted in breadth, spirit and scope in accordance with the appended claims.

Claims

1. A method comprising: System analysis, including the processor, corresponds to a traveling wave of a fault in a power transmission system, including: Receive data representing the current and voltage components of a traveling wave; The data is stored in a storage device for use in determining the location of the fault. Transforming the data into a wavelet transform result includes performing a wavelet transform; and The wavelet transform results are used for the protection of the power transmission system, wherein the protection of the power transmission system includes traveling wave-based distance protection, and the use of the wavelet transform results for the protection of the power transmission system includes: using a first scale of the wavelet transform results of voltage and current traveling waves for traveling wave-based distance protection.

2. The method according to claim 1, further comprising: Analog current and voltage information is received from corresponding current and voltage sensors coupled to the power transmission system. The analog current and voltage information is filtered by bandpass filtering to obtain traveling wave information including analog current and voltage information. The traveling wave information is then digitized into data representing the current and voltage components of the traveling wave.

3. The method of claim 1, wherein transforming the data includes transforming it via wavelet transform, which includes transforming the data into a spatial vector including a current vector and a voltage vector via α-β transform, and performing wavelet transform on the current vector and the voltage vector to obtain the wavelet transform result.

4. The method according to claim 1, wherein, The protection of the power transmission system further includes boundary protection based on traveling waves, and the application of the wavelet transform results to the protection of the power transmission system further includes: using the first and fourth scales of the wavelet transform results of the current traveling waves for boundary protection based on traveling waves.

5. The method according to claim 1, wherein, Using the wavelet transform result for the protection of the power transmission system further includes: using downsampled values ​​corresponding to the forward and reverse traveling waves to determine the direction of the traveling wave caused by the fault.

6. The method according to claim 5, wherein, The protection of the power transmission system further includes direction comparison protection based on traveling waves, and the use of the wavelet transform result for the protection of the power transmission system further includes: using traveling wave direction data for direction comparison protection, wherein the direction comparison protection compares the fault direction generated by the traveling wave at the end of the transmission system.

7. The method according to claim 1, wherein, The protection of the power transmission system further includes differential protection based on traveling waves, and the application of the wavelet transform results to the protection of the power transmission system further includes: multiplying the fourth scale of the wavelet transform results of voltage traveling waves and the fourth scale of the wavelet transform results of current traveling waves by the system surge impedance value to express forward and reverse traveling wave information; using the forward and reverse traveling wave information to obtain differential traveling wave information and bias traveling wave information; and using the differential traveling wave information and bias traveling wave information for differential protection based on traveling waves.

8. The method according to claim 1, wherein, The protection of the power transmission system further includes polarization comparison protection based on traveling waves, and the application of the wavelet transform result to the protection of the power transmission system further includes: comparing the polarization of the current traveling waves at both ends of the power transmission system to perform polarization comparison protection.

9. The method according to claim 1, wherein, Using the wavelet transform result for the protection of the power transmission system further includes: executing unit protection to output a trip signal within defined boundaries.

10. The method according to claim 1, wherein, Using the wavelet transform result for the protection of the power transmission system further includes: performing non-unit protection to output a trip signal.

11. The method according to claim 1, wherein, Storing the data in a storage device for fault location determination includes providing time-based snapshot data to a single-ended traveling wave fault locator.

12. The method according to claim 1, wherein, Storing the data in a storage device for fault location determination includes providing time-based snapshot data to a two-end traveling wave fault locator.

13. The method of claim 12, further comprising: Obtain the actual fault distance value, and use the actual fault distance value to improve the accuracy of fault location.

14. The method according to claim 1, wherein, Storing the data in a storage device for fault location determination includes providing time-based snapshot data to a multi-terminal traveling wave fault locator.

15. The method of claim 14, further comprising: The multi-terminal traveling wave fault locator iterates across a set of nodes corresponding to traveling wave devices deployed at multiple ends to locate the faulty section.

16. A system comprising: Traveling wave device configured to analyze traveling wave data representing traveling waves corresponding to faults on a power transmission system, the traveling wave device comprising: processor, The wavelet transform component, via the processor, transforms the traveling wave data into a wavelet transform result, and A protection component that uses the wavelet transform result to output a trip signal for power transmission system protection, wherein the power transmission system protection includes traveling wave-based distance protection, and the protection component uses a first scale of the wavelet transform result of voltage and current traveling waves for traveling wave-based distance protection.

17. The system of claim 16, wherein the traveling wave device is further configured to store a digital representation of the traveling wave data in a storage device for offline fault location determination.

18. A machine-readable storage medium including executable instructions, the executable instructions causing a device including a processor to perform operations in response to execution, the operations including: Analog current and voltage information is received from corresponding current and voltage sensors coupled to the power transmission system; The analog current and voltage information is filtered by bandpass filtering to obtain traveling wave information that includes analog current and voltage information; The traveling wave information is digitized into data representing the current and voltage components of the traveling wave; as well as The data is stored in a storage device for fault location determination. The operation further includes: transforming the data into a spatial vector including a current vector and a voltage vector via an α-β transform; transforming the data into a wavelet transform result via a wavelet transform; and using the wavelet transform result for the protection of the power transmission system, wherein the protection of the power transmission system includes traveling wave-based distance protection, and using the wavelet transform result for the protection of the power transmission system includes: using a first scale of the wavelet transform result of the voltage and current traveling waves for traveling wave-based distance protection.

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