A method, device, system and medium for testing parameters of a newly-built parallel asymmetric line without power interruption

Abstract

This invention discloses a method, apparatus, system, and medium for uninterrupted power supply testing of parameters for newly constructed parallel asymmetrical lines within the same corridor. The method includes: obtaining parameters of existing lines within the same corridor... n The sequence parameters of the line were retrieved; the end of the new line was short-circuited to ground, and a different frequency excitation signal was injected into its head; the response voltage and current at the head of the new line were measured simultaneously, as well as all... n The invention involves measuring the coupling voltage and current at the beginning and end of a energized line; calculating the zero-sequence impedance of the newly constructed line and the mutual inductance impedance between the new line and each energized line based on the acquired existing line sequence parameters and synchronous measurement data; then disconnecting the end of the new line and injecting a different frequency excitation signal, measuring the response voltage and current, and calculating the zero-sequence admittance of the new line. This invention enables uninterrupted testing of the parameters of a newly constructed parallel asymmetrical line under energized operating conditions, effectively resolving the contradiction between line parameter testing and grid power supply reliability.

Description

Technical Field

[0001] This invention relates to the field of transmission line parameter testing, specifically a method, apparatus, system, and medium for uninterrupted power supply testing of parameters of newly built parallel asymmetrical transmission lines in the same corridor. Background Technology

[0002] Power lines, as channels for transmitting electricity, are crucial infrastructure for ensuring national energy security, and their safe and stable operation is vital to my country's economic development. The electrical parameters of power lines, including impedance, capacitance, and mutual inductance, are influenced by multiple factors such as line structure, corridor environment, and terrain along the route. Therefore, actual measurements are necessary to accurately obtain these parameters in order to achieve core functions such as relay protection setting, power flow calculation, stability control, and fault location.

[0003] The mandatory and recommended national standards such as the "Guidelines for the Safety and Stability of Power Systems" (GB 38755-2019), the "Standard for Acceptance Testing of Electrical Equipment in Electrical Installation Engineering" (GB 50150-2016), and the "Principles for Relay Protection Configuration and Setting Calculation of Traction Substation Power Supply Lines" (GB / T38435-2019) all require the actual measurement of line electrical parameters. Standards such as the "Operation and Setting Procedures for 220kV~750kV Power Grid Relay Protection Devices" (DL / T 559-2018) and the "3kV~110kV Power Grid Relay Protection Devices" (DL / T584-2017) specify that the measured line parameters include the positive sequence and zero sequence impedances and positive sequence and zero sequence admittances, as well as mutual inductance impedance.

[0004] With the rapid development of power grids, parallel lines on the same tower are becoming increasingly common, and the coupling relationship between circuits in parallel lines on the same tower is complex. If the influence of inter-circuit coupling is not considered, the measurement error of zero-sequence impedance for parallel lines on the same tower can reach over 30%, seriously affecting the reliable operation of relay protection. With the rapid development of power grids, a large number of major projects such as clean energy bases, ultra-high voltage transmission lines, and offshore wind power grid connection are about to be implemented, making parallel lines on the same tower increasingly common. The contradiction between line parameter testing and power grid reliability is becoming increasingly prominent, making uninterrupted line parameter testing technology a necessity that meets national strategic development needs and is urgently required.

[0005] Invention patent CN 105223436B discloses a method for measuring and calculating parameters of a double-circuit AC transmission line on the same tower, and CN 105548715B discloses a method for measuring parameters of a four-circuit AC transmission line on the same tower. These methods can be used to test the positive-sequence and zero-sequence impedance parameters, as well as the inter-circuit coupling parameters, of double-circuit or four-circuit lines on the same tower. However, both patents are only applicable to parameter testing of lines on the same tower, i.e., lines on the same tower have equal self-impedance parameters and are symmetrical lines; they are not applicable to parameter testing of asymmetrical lines on the same tower or in parallel. Furthermore, the above methods require the tested line to be de-energized, making it difficult to resolve the contradiction between line parameter testing and stable power supply from the power grid.

[0006] Invention patent CN 119574972A discloses a live-line measurement method and device for zero-sequence distributed parameters of a double-circuit transmission line with a common busbar at both ends. This method can only be used to measure the zero-sequence parameters of double-circuit transmission lines with a common busbar on the same or different towers. The method requires briefly disconnecting and reclosing one phase of the circuit breaker at the end of the first transmission line to measure the parameters, and then briefly disconnecting and reclosing one phase of the circuit breaker at the end of the second transmission line to measure the parameters again. This method requires changing the normal operating state of the line, causing single-phase tripping, which can cause significant disturbance to the power grid and potentially lead to faults in voltage-sensitive user equipment, threatening the safety of power supply. Therefore, it is difficult to implement in practical engineering. Patent 121142162A discloses a live testing device and method for zero-sequence impedance parameters of mutually inducted lines. It can perform line parameter testing in an environment where one circuit in a double-circuit line is energized and the other circuit is de-energized for maintenance. However, this method requires that the self-parameters of the two circuits be equal, meaning it is only applicable to the testing of symmetrical line parameters. Furthermore, the two patents mentioned above are only applicable to the live testing of two circuit parameters and cannot solve the parameter testing of multi-circuit coupled lines in the same corridor.

[0007] To address the shortcomings of existing technologies, this invention proposes a device, system, and medium for uninterrupted testing of parameters of newly constructed parallel asymmetrical lines within the same corridor. Taking into full account the actual operating conditions of power transmission projects, this method tests the parameters of newly constructed asymmetrical lines and inter-circuit coupling parameters within the same corridor while the existing lines are energized. This approach eliminates the need for power outages on the existing lines, effectively resolving the conflict between line parameters and stable power supply in densely populated corridor environments. This method is applicable to testing the parameters of parallel lines under various asymmetrical operating conditions, such as different voltages, unequal distances, and unequal lengths, and can solve the problem of uninterrupted testing of parameters for double-circuit and multi-circuit asymmetrical lines within the same corridor. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method and system for uninterrupted power supply testing of parameters for newly constructed parallel asymmetrical lines in the same corridor. This method enables live testing of parameters for newly constructed parallel asymmetrical lines under energized operating conditions of existing lines in the same corridor. It is applicable to testing parameters of parallel lines under various asymmetrical operating conditions such as different voltages, unequal distances, and unequal lengths, and does not require power outages of the operating lines. This effectively resolves the contradiction between line parameter testing and power grid reliability in complex power grid topologies.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] A method for uninterrupted power supply testing of parameters of newly constructed parallel asymmetrical lines in the same corridor includes the following steps:

[0011] Before the line is put into operation, the positive sequence impedance, positive sequence admittance, zero sequence impedance and zero sequence admittance of the existing n lines in the same corridor are obtained sequentially using the sequence impedance parameter test method, where n≥1;

[0012] After the n-circuit lines are put into operation, in the case of newly built parallel lines on the same tower in the same corridor, the positive sequence impedance and positive sequence admittance of the newly built lines are obtained by using the sequence impedance parameter test method.

[0013] The end of the newly built line is short-circuited and grounded. A different frequency excitation signal is injected into the beginning of the newly built line. The response voltage and current at the beginning of the newly built line, as well as the coupling voltage and coupling current at the beginning and end of all n energized lines, are measured synchronously to obtain synchronous measurement data.

[0014] Based on the zero-sequence parameters of the n live lines and the synchronous measurement data, calculate the zero-sequence impedance of the new line and the mutual inductance impedance between the new line and each live line.

[0015] The end of the new line is disconnected and left suspended. A different frequency excitation signal is injected into the beginning of the new line. The response voltage and current at the beginning of the new line are measured, and the zero-sequence admittance of the new line is calculated.

[0016] Furthermore, the synchronous measurement of the coupling voltage and coupling current at the beginning and end of all n live lines specifically includes: obtaining the voltage and current secondary side signals from the secondary measurement circuits of the voltage transformers and current transformers at the beginning and end of each live line, and converting them to the primary side according to the turns ratio.

[0017] Furthermore, the calculation of the zero-sequence impedance of the newly constructed line and the mutual inductance impedance between the newly constructed line and each energized line specifically includes:

[0018] For each energized line, calculate the voltage drop and average current of the line based on its first and last coupled voltages and coupled currents.

[0019] Based on the coupling voltage drop, average current and known zero-sequence parameters of the energized line, the mutual inductance impedance between the newly built line and each energized line is calculated.

[0020] The zero-sequence impedance of the new line is calculated based on the response voltage and response current at the beginning of the new line and the mutual inductance obtained by solving.

[0021] Furthermore, the newly constructed line differs from the existing energized line in at least one aspect, such as parallel length, parallel spacing, or conductor type, resulting in asymmetric line parameters.

[0022] Furthermore, the heterogeneous excitation signal consists of two sets of high-amplitude heterogeneous current signals with frequencies different from the power frequency.

[0023] A non-disconnect power supply testing device for parameters of newly constructed parallel asymmetrical lines in the same corridor, used to implement the method described above, the device comprising:

[0024] The sequence parameter acquisition unit is used to sequentially acquire the zero-sequence impedance and zero-sequence admittance of the existing n circuits in the same corridor using the sequence impedance parameter test method before the line is put into operation, where n≥1; after the n circuits are put into operation, in the case of newly built parallel lines on the same tower in the same corridor, the positive-sequence impedance and positive-sequence admittance of the newly built lines are acquired using the sequence impedance parameter test method.

[0025] The excitation signal injection unit has its output terminal connected to the beginning of the new line to inject a different frequency excitation signal at the beginning of the new line.

[0026] The synchronous measurement unit is used to short-circuit and ground the end of the newly built line, inject a different frequency excitation signal at the beginning of the newly built line, and synchronously measure the response voltage and current at the beginning of the newly built line, as well as the coupling voltage and coupling current at the beginning and end of all n energized lines, to obtain synchronous measurement data.

[0027] The parameter calculation unit is used to calculate the zero-sequence impedance of the newly built line and the mutual inductance impedance between the newly built line and each of the existing lines based on the zero-sequence parameters of the n-circuit live lines and the synchronous measurement data; disconnect and suspend the end of the newly built line, inject a different frequency excitation signal at the beginning of the newly built line, measure the response voltage and current at the beginning of the newly built line, and calculate the zero-sequence admittance of the newly built line.

[0028] Furthermore, the synchronous measurement unit includes multiple voltage measurement channels and current measurement channels. Each channel is connected to the secondary side of the voltage transformer and current transformer at each measurement point via signal lines. The synchronous measurement unit has a synchronous sampling function to ensure the time consistency of all measurement data.

[0029] Furthermore, the excitation signal injection unit includes a frequency converter and a power amplifier. The frequency converter generates a frequency signal, which is then amplified and injected into the head end of the newly built line.

[0030] Furthermore, the parameter calculation unit includes:

[0031] The first calculation module is used to calculate the coupling voltage drop and average current of each live line based on the coupling voltage and coupling current at the beginning and end of each live line.

[0032] The second calculation module is used to solve the mutual inductance impedance between the newly built line and each existing line based on the coupling voltage drop, average current, known zero-sequence impedance, and known coupling parameters between the existing lines.

[0033] The third calculation module is used to calculate the zero-sequence impedance of the new line based on the response voltage and response current at the beginning of the new line and the mutual inductance impedance obtained by solving.

[0034] The fourth calculation module is used to calculate the zero-sequence admittance of the new line after disconnecting and suspending the end of the new line and injecting a different frequency excitation signal at the beginning of the new line. This is based on the measured response voltage and current at the beginning of the new line.

[0035] Furthermore, the device also includes a display unit for displaying the calculated zero-sequence parameters of the newly built line and the mutual inductance impedance between the newly built line and each energized line.

[0036] A non-power-off testing system for parameters of newly built parallel asymmetrical lines in the same corridor includes: a computer-readable storage medium and a processor;

[0037] The computer-readable storage medium is used to store executable instructions;

[0038] The processor is used to read executable instructions stored in the computer-readable storage medium and execute the above-described method for uninterrupted power supply testing of parameters of newly built parallel asymmetrical lines in the same corridor.

[0039] A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method for uninterrupted power testing of parameters of newly constructed parallel asymmetrical lines in the same corridor.

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] (1) Compared with the prior art, the non-power-off testing method for the parameters of newly built parallel lines in the same corridor proposed in this invention, based on fully considering the actual working conditions of power transmission engineering construction, tests the parameters of newly built asymmetrical lines and the coupling parameters between circuits in the same corridor under the energized operation condition of the lines in the same corridor. This method does not require power outage of the lines in the same corridor and can effectively solve the contradiction between line parameter testing and power supply reliability in complex power grid topology.

[0042] (2) The parallel asymmetric line parameter uninterrupted power supply test method proposed in this invention is applicable to the test of parallel line self-parameters and inter-circuit coupling parameters under various asymmetric working conditions such as different voltages, unequal distances, and unequal lengths of parallel lines. It effectively reduces the error caused by assuming that the self-parameters of lines on the same tower are equal in the existing methods, and can solve the problem of accurate test of parallel asymmetric line parameters in the same corridor. It is applicable to the test of line parameters under various working conditions such as the same corridor, the same tower, and parallel operation.

[0043] (3) The parallel asymmetrical line parameter non-stop test method proposed in this invention can perform non-stop test on the parameters of double-circuit and multi-circuit asymmetrical lines in the same channel. It is applicable to the test of any number of newly built asymmetrical line parameters in the same channel. Compared with the existing technology, it has a wider application range and higher measurement accuracy, and does not require single-phase grounding or full-line shutdown of the same corridor line. Attached Figure Description

[0044] Figure 1 This is a flowchart of the uninterrupted power supply testing technology for the parameters of newly built parallel asymmetrical lines in the same corridor proposed in this invention;

[0045] Figure 2 This is a schematic diagram of parameter testing for a newly built parallel asymmetrical line under the energized operation condition of a single line in the same corridor, as proposed in this invention.

[0046] Figure 3 This is a schematic diagram of parameter testing for a newly built parallel asymmetrical line under the energized operation condition of n-circuit lines in the same corridor, as proposed in this invention.

[0047] Figure 4 This is a topology diagram of multiple densely packed lines in the same corridor in an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Please see Figure 1 The first aspect of this invention provides a method for uninterrupted power supply testing of parameters of newly constructed parallel asymmetrical lines in the same corridor, comprising the following steps:

[0050] For newly built single-circuit lines without parallel lines in the same corridor, the sequence impedance test method is used to measure the sequence parameters of the line, including positive sequence impedance, zero sequence impedance, positive sequence admittance, and zero sequence admittance.

[0051] After the single-circuit line is put into operation, in the case of a newly built parallel asymmetrical line in the same corridor, under the energized operation condition of the single-circuit line, a different frequency excitation signal is injected into the newly built line, and the response voltage and current of the newly built line, the coupling voltage and current of the energized line are measured simultaneously, and the zero-sequence parameters and inter-circuit coupling parameters of the newly built line are calculated.

[0052] After the n-circuit lines are put into operation, in the case of newly built parallel asymmetrical lines in the same corridor, under the energized operation condition of the n-circuit lines, a different frequency excitation signal is injected into the newly built lines, and the response voltage and current of the newly built lines and the coupling voltage and current of (1~n) energized lines are measured simultaneously to calculate the zero-sequence parameters and inter-circuit coupling parameters of the newly built lines.

[0053] Specifically, for newly constructed single-circuit lines without parallel lines within the same corridor, the sequence parameters of the line are measured using a sequence impedance test method, as follows:

[0054] The end of the single-circuit line is short-circuited and grounded. At the beginning of the line, a set of current lines and voltage lines of the same wire diameter and material are connected to each of the three phases. Three-phase symmetrical frequency excitation signals are injected into the current lines, and the response voltage is measured synchronously. and current The positive sequence impedance of the line is calculated according to formula (1). :

[0055]

[0056] In the formula .

[0057] In the formula, the lower right corner 's' indicates a short circuit at the end of the line; 'o' indicates an open circuit at the end of the line; '1' represents a positive sequence parameter; '0' represents a zero sequence parameter; the number (i) in the register indicates the line number i; the number (ij) in the register indicates the coupling parameter between line i and line j; ABC indicates the phase. The upper right corner "Beginning" indicates the electrical quantity at the beginning of the line; "End" indicates the electrical quantity at the end of the line, and the same applies below.

[0058] The three-phase voltage and current lines of the single-circuit line are short-circuited respectively, and a different frequency excitation signal is injected into the current line to simultaneously measure the response voltage. and current The zero-sequence impedance of the line is calculated using the following formula. :

[0059]

[0060] The end of the single-circuit line is left suspended, and a three-phase symmetrical frequency excitation signal is injected at the beginning end according to the above steps, while the response voltage is measured synchronously. and current The positive-sequence admittance of the circuit is calculated using the following formula. :

[0061]

[0062] The three-phase voltage and current lines of the single-circuit line are short-circuited respectively, and a zero-sequence heterogeneous frequency excitation signal is injected at the beginning of the line, while the response voltage is measured synchronously. and current The zero-sequence admittance of the circuit is calculated using the following formula. :

[0063]

[0064] In the case of a newly constructed parallel asymmetrical line in the same corridor after the single-circuit line is put into operation, under the energized operation condition of the single-circuit line, a different frequency excitation signal is injected into the newly constructed line, and the response voltage and current of the newly constructed line, as well as the coupling voltage and current of the energized line, are measured simultaneously. The zero-sequence parameters and inter-circuit coupling parameters of the newly constructed line are calculated. See details. Figure 2 Specifically:

[0065] The single-circuit line that is energized is designated as line 1, and the newly built parallel asymmetrical line in the same corridor is designated as line 2.

[0066] The asymmetry mentioned above includes the difference in parameters between line 2 and line 1 caused by different operating conditions such as different lengths, different parallel spacing, and different conductor types, which makes it difficult to test using the traditional distributed parameter testing method for symmetrical lines.

[0067] The positive sequence impedance of line 1 Zero-sequence impedance Positive-sequence admittance Zero-sequence admittance This was measured using the aforementioned steps before commissioning;

[0068] The positive sequence impedance of line 2 and positive-order admittance The test method refers to the positive sequence parameter test method for a newly built single-circuit line without parallel asymmetrical lines in the same corridor.

[0069] The zero-sequence parameter and inter-loop coupling parameter tests for line 2 must consider the influence of inter-loop coupling in parallel lines. Since line 1 is already energized, a non-disconnect testing method is required, specifically:

[0070] The neutral point of the transformer connecting the beginning and end of line 1 is grounded. The end of line 2 is short-circuited and grounded. A high-amplitude heterogeneous frequency excitation signal is injected into the beginning of line 2, and the response voltage of line 2 is measured simultaneously. and current Line 1 head coupling voltage and current Terminal coupling voltage and current ;

[0071] The voltage and current at the beginning and end of line 1 are measured from the PT and CT secondary terminals of the power meter panel or PMU cabinet in the secondary compartment at the beginning and end of the line, and then multiplied by the transformation ratio of PT and CT respectively.

[0072] The specific method for uninterrupted testing of the zero-sequence impedance of line 2 and the mutual inductance impedance of lines 1 and 2 is as follows:

[0073] The coupling voltage drop of line 1 is calculated using the following formula, taking the voltage and current at the beginning and end of line 1. and average current :

[0074] (5)

[0075] The voltage and current signals of line 2 and line 1, as well as the zero-sequence impedance of line 1, are used to... The mutual inductance impedances of line 1 and line 2 are calculated using the following formula. The zero-sequence impedance of line 2 :

[0076] (6)

[0077] The zero-sequence admittance test method for line 2 specifically involves: suspending the end of line 2, injecting a zero-sequence hetero-frequency excitation signal at the beginning of the line, and simultaneously measuring the response voltage. and current Zero-sequence admittance of line 2 The calculation formula is:

[0078]

[0079] Since both ends of line 1 are grounded through the neutral point of a transformer, the electrostatic coupling voltage of line 1... The zero-sequence admittance of line 2 is close to 0 and can be ignored. The calculation formula can be simplified to:

[0080]

[0081] In the case of newly constructed parallel asymmetrical lines along the same corridor after the n-circuit lines are put into operation, under the energized operation condition of the n-circuit lines, a different frequency excitation signal is injected into the newly constructed lines, and the response voltage and current of the newly constructed lines, as well as the coupling voltage and current of the (1~n) energized lines, are measured simultaneously. The zero-sequence parameters and inter-circuit coupling parameters of the newly constructed lines are calculated. See details. Figure 3 Specifically:

[0082] The single-circuit line operating under power is designated as line 1, line 2, ... line n, and the newly built parallel asymmetrical line in the same corridor is designated as line n+1;

[0083] The asymmetry mentioned here includes the fact that the parameters of line n+1 and line 1~n are different due to different operating conditions such as different lengths of line n+1 and different parallel spacings, and different conductor types, making it difficult to use the traditional distributed parameter testing method for symmetrical lines for testing.

[0084] The positive sequence impedance of the lines (1~n) and admittance Zero-sequence impedance and admittance Measured by the aforementioned steps;

[0085] The positive sequence impedance of line n+1 and admittance The test method refers to the positive sequence parameter test method for a newly built single-circuit line without parallel lines in the same corridor.

[0086] The zero-sequence parameter and inter-loop coupling parameter tests for line n+1 need to consider the influence of inter-loop coupling in parallel lines. Since lines (1~n) are already energized, a non-energized testing method is required, specifically:

[0087] The neutral point of the transformer connecting the first and last ends of the lines (1~n) is grounded. The end of line n+1 is short-circuited and grounded. A high-amplitude heterogeneous frequency excitation signal is injected at the beginning of line n+1, and the response voltage of line n+1 is measured simultaneously. and current Coupled voltage at the beginning of line (1~n) and current Terminal coupling voltage and current ;

[0088] The voltage and current at the beginning and end of the line (1~n) are measured from the PT and CT secondary terminals of the power meter panel or PMU cabinet in the secondary compartment at the beginning and end of the line, and then multiplied by the transformation ratio of the PT and CT respectively.

[0089] The specific method for uninterrupted testing of the zero-sequence impedance of line n+1 and the mutual inductance impedance of line n+1 and lines (1~n) is as follows:

[0090] Calculate the coupling voltage drop of lines (1~n) by taking the voltage and current at the beginning and end of the lines (1~n) according to the following formula. and average current :

[0091] (9)

[0092] The voltage and current signals of line n+1 and lines (1~n), as well as the zero-sequence impedance of lines (1~n) are used. Mutual inductance impedance between lines (1~n) The mutual inductance impedances of line n+1 and lines (1~n) are calculated using the following formula. The zero-sequence impedance of line n+1 :

[0093] (10)

[0094] The zero-sequence admittance test method for line n+1 specifically involves: leaving the end of line n+1 suspended, injecting a zero-sequence hetero-frequency excitation signal at the beginning of the line, and simultaneously measuring the response voltage. and current The zero-sequence admittance of line n+1 The calculation formula is:

[0095]

[0096] Since the two ends of the live line (1~n) are grounded through the neutral point of the transformer, the electrostatic coupling voltage of the line (1~n) The zero-sequence admittance of line n+1 is close to 0 and can be ignored. The calculation formula can be simplified to:

[0097]

[0098] Example 1

[0099] A new 500kV transmission line is being constructed in a 500kV transmission project. There are no other parallel lines in the corridor, and this line is designated as Line 1. Line 1 is 61.291km long, with conductor type 4×JL3 / G1A-720 / 50 and two OPGW-150 ground wires. After completion, the sequence impedance parameter testing method is used. Different frequency excitation signals are injected into Line 1, and the positive-sequence and zero-sequence response voltages and currents are measured, referring to... Figure 1 See the table below for details.

[0100] Table 1. Measurement results of positive sequence and zero sequence voltage and current for line 1

[0101]

[0102] After calculating the sequence parameters of the line according to formulas (1)-(4), the different frequency parameters are converted to the power frequency to obtain the positive sequence and zero sequence impedance and admittance of line 1, where the admittance is converted to capacitance, as detailed in the table below.

[0103] Table 2 Positive Sequence and Zero Sequence Parameters for Line 1

[0104]

[0105] Example 2

[0106] In Example 1, after Line 1 was put into operation, a new 500kV line, designated Line 2, was constructed parallel to Line 1 within the same corridor. Line 2 is 64.927km long, with conductor type 4×JL3 / G1A-720 / 50 and two OPGW-150 ground wires. It runs parallel to Line 1 for 53.482km, with an average spacing of 50m and a minimum of 45m. Because Line 2 differs from Line 1 in length and parallel spacing, their parameters are different, resulting in an asymmetrical structure.

[0107] After the completion of Line 2, the positive sequence impedance parameters of Line 2 were obtained by using the sequence impedance parameter test method, as shown in Table 1.

[0108] Table 3. Line 2 Positive Sequence Parameters

[0109]

[0110] Line 1 and Line 2 run parallel over a long distance. The coupling between the two lines affects the zero-sequence parameters of Line 2, and it is necessary to measure the inter-circuit coupling parameters between the two lines. Since Line 1 is already energized and there are no conditions for power outage, the uninterrupted power-on testing technique for the parameters of newly built parallel asymmetrical lines in the same corridor after a single-circuit line is put into operation is used for testing, referring to... Figure 1 and Figure 2 The details are as follows:

[0111] The beginning and end of line 1 are grounded through the neutral point of a transformer to form a path for zero-sequence coupled current. The end of line 2 is short-circuited and grounded, and a high-amplitude heterogeneous frequency excitation signal is injected into the beginning of line 2. The response voltage of line 2 is measured simultaneously. and current Line 1 head coupling voltage and current Terminal coupling voltage and current ;Calculate the coupling voltage drop of line 1 by taking the voltage and current at the beginning and end of line 1 according to formula (5). and average current See Table 4 for details.

[0112] Table 4. Uninterruptible power supply test data for zero-sequence and inter-circuit coupling parameters of parallel asymmetrical lines in the same corridor.

[0113]

[0114] The voltage and current signals of line 2 and line 1, as well as the zero-sequence impedance of line 1, are used to input the voltage and current signals of line 2 and line 1. After calculating the different frequency parameters according to formula (6), the different frequency impedances are then converted to the power frequency to obtain the coupling parameters of line 1 and line 2. The zero-sequence parameter of line 2 See Table 5 for details.

[0115] Table 5 Zero-sequence impedance of line 2 and its mutual inductance with line 1

[0116]

[0117] Example 3

[0118] A certain 500kV transmission project has undergone multiple renovations, with four transmission lines densely erected along the same corridor. The lengths of the lines with coupling relationships vary, as do the sections, lengths, and spacing of the lines running parallel to each tower. The inter-circuit coupling relationships are complex; see details below. Figure 4 Among them, Line 2 and Line 1 have no parallel sections on the same tower; Line 3 and Line 1 share a parallel tower for 49km; Line 3 and Line 2 share a parallel tower for 34km; Line 4 and Line 1 share a parallel tower for 43km; Line 4 and Line 2 share a parallel tower for 49km; and Line 4 and Line 3 share a parallel tower for 54km. Because the lengths of the four lines are different, and the parallel sections and lengths between each pair are also different, the relationships between each pair are asymmetrical, and the coupling relationships between the circuits are complex. See details... Figure 4 .

[0119] Traditional methods require all four coupled lines to be shut down simultaneously to test the zero-sequence and coupling parameters. The uninterrupted power supply testing method described in this patent allows testing to be conducted with all other parallel lines energized before the new line is put into operation, meaning that power outages of parallel lines on the same tower are not required. (Refer to...) Figure 3 The details are as follows.

[0120] After the completion of lines 1 to 3, the zero-sequence parameters and inter-circuit coupling parameters of lines 1 to 3 were measured sequentially according to the power-off test method described above. The test method is based on the aforementioned invention content, as well as Embodiments 1 and 2, and is detailed in Table 6.

[0121] Table 6. Results of Uninterrupted Power-Off Tests on Zero-Sequence and Inter-Circuit Coupling Parameters for Lines 1-3

[0122]

[0123] After lines 1-3 are put into operation, a parallel asymmetrical line 4 will be constructed on the same tower within the same corridor. Following the aforementioned uninterrupted power supply testing method, a high-amplitude heterogeneous frequency excitation signal will be injected at the beginning of line 4, and the response voltage of line 4 will be measured simultaneously. and current Coupled voltage at the beginning of lines 1-3 and current Terminal coupling voltage and current ;Calculate the coupling voltage drop of lines 1-3 by taking the voltage and current at the beginning and end of lines 1-3 according to formula (5). and average current See Table 7 for details.

[0124] Table 7. Uninterruptible power supply test data for zero-sequence and inter-circuit coupling parameters of multiple parallel asymmetrical lines in the same corridor.

[0125]

[0126] According to formula (9), the coupling parameters of line 4 and lines 1~3 are... The calculation formula is simplified to:

[0127] (13)

[0128] According to formula (9) and the coupling parameters of line 4 and lines 1~3 The zero-sequence parameter of line 4 Simplified to:

[0129] (14)

[0130] The voltage and current signals of lines 1-4, and the zero-sequence impedance of lines 1-3 are used to... Inter-loop coupling parameters After calculating the zero-sequence parameters of line 4 and its coupling parameters with lines 1 to 3 according to formulas (11)-(12), the zero-sequence parameters of line 4 are converted to the power frequency to obtain the zero-sequence parameters of line 4. and its coupling parameters with lines 1-3 See Table 8 for details.

[0131] Table 8 Test results of zero-sequence parameters of line 4 and its coupling parameters with lines 1-3

[0132]

[0133] Compared with the prior art, the present invention provides the following features and effects:

[0134] 1. Enables uninterrupted testing and ensures power supply reliability: This invention, under the condition of existing lines being energized, injects a different frequency excitation signal into the newly built line and simultaneously measures the response electrical quantity of the newly built line and the coupling electrical quantity of the existing line. The zero-sequence parameters and inter-circuit coupling parameters of the newly built line can be calculated without the need to shut down the existing lines, effectively solving the contradiction between line parameter testing and stable power supply from the power grid.

[0135] 2. Applicable to various asymmetrical operating conditions with high testing accuracy: This invention is applicable to parameter testing of newly built lines and existing lines under asymmetrical operating conditions such as different voltage levels, different parallel spacing, different line lengths, and different conductor types. It does not require the assumption that the line parameters are symmetrical and can accurately reflect the line parameters under the actual complex topology. The measurement accuracy is significantly better than that of traditional methods.

[0136] 3. Supports complex coupling scenarios with multiple circuits: This invention can handle complex coupling situations with multiple energized circuits in the same corridor. When calculating the parameters of a new line, it fully considers the mutual coupling effects between existing lines. Through synchronous measurement and simultaneous solution, it accurately obtains the mutual inductance impedance between the new line and each energized circuit, thus having a wider range of applications.

[0137] 4. Synchronous measurement to ensure data consistency: This invention ensures the time consistency of each measurement data by synchronously measuring the voltage and current signals at the beginning and end of newly built lines and all energized lines, providing a foundation for the accuracy of subsequent parameter calculations and avoiding errors introduced by asynchronous measurements.

[0138] A second aspect of the present invention provides an uninterrupted power supply testing device for parameters of newly constructed parallel asymmetrical lines in the same corridor, used to implement the method described above, the device comprising:

[0139] The sequence parameter acquisition unit is used to sequentially acquire the zero-sequence impedance and zero-sequence admittance of the existing n circuits in the same corridor using the sequence impedance parameter test method before the line is put into operation, where n≥1; after the n circuits are put into operation, in the case of newly built parallel lines on the same tower in the same corridor, the positive-sequence impedance and positive-sequence admittance of the newly built lines are acquired using the sequence impedance parameter test method.

[0140] The excitation signal injection unit has its output terminal connected to the beginning of the new line to inject a different frequency excitation signal at the beginning of the new line.

[0141] The synchronous measurement unit is used to short-circuit and ground the end of the newly built line, inject a different frequency excitation signal at the beginning of the newly built line, and synchronously measure the response voltage and current at the beginning of the newly built line, as well as the coupling voltage and coupling current at the beginning and end of all n energized lines, to obtain synchronous measurement data.

[0142] The parameter calculation unit is used to calculate the zero-sequence impedance of the newly built line and the mutual inductance impedance between the newly built line and each of the existing lines based on the zero-sequence parameters of the n-circuit live lines and the synchronous measurement data; disconnect and suspend the end of the newly built line, inject a different frequency excitation signal at the beginning of the newly built line, measure the response voltage and current at the beginning of the newly built line, and calculate the zero-sequence admittance of the newly built line.

[0143] Another aspect of the present invention provides a non-power-off testing system for parameters of newly constructed parallel asymmetrical lines in the same corridor, comprising: a computer-readable storage medium and a processor;

[0144] The computer-readable storage medium is used to store executable instructions;

[0145] The processor is used to read executable instructions stored in the computer-readable storage medium and execute the uninterrupted power supply test method for parameters of newly built parallel asymmetrical lines in the same corridor as described in the first aspect.

[0146] In another aspect, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the uninterrupted power-off testing method for parameters of newly constructed parallel asymmetrical lines in the same corridor as described in the first aspect.

[0147] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0148] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0149] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0150] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for uninterrupted power supply testing of parameters of newly constructed parallel asymmetrical lines in the same corridor, characterized in that, Includes the following steps: Before the line is put into operation, the zero-sequence impedance and zero-sequence admittance of the existing n lines in the same corridor are obtained sequentially using the sequence impedance parameter test method, where n≥1; after the n lines are put into operation, when new parallel lines are built on the same tower in the same corridor, the positive-sequence impedance and positive-sequence admittance of the new lines are obtained using the sequence impedance parameter test method. The end of the newly built line is short-circuited and grounded. A different frequency excitation signal is injected into the beginning of the newly built line. The response voltage and current at the beginning of the newly built line, as well as the coupling voltage and coupling current at the beginning and end of all n energized lines, are measured synchronously to obtain synchronous measurement data. Based on the zero-sequence parameters of the n live lines and the synchronous measurement data, calculate the zero-sequence impedance of the new line and the mutual inductance impedance between the new line and each live line. The end of the newly constructed line is disconnected and left suspended. A different frequency excitation signal is injected into the beginning of the newly constructed line. The response voltage and current at the beginning of the newly constructed line are measured, and the zero-sequence admittance of the newly constructed line is calculated.

2. The method according to claim 1, characterized in that, The synchronous measurement of the coupling voltage and coupling current at the beginning and end of all n live lines specifically includes: obtaining the voltage and current secondary side signals from the secondary measurement circuits of the voltage transformers and current transformers at the beginning and end of each live line, and converting them to the primary side according to the transformation ratio.

3. The method according to claim 1, characterized in that, The calculation of the zero-sequence impedance of the newly constructed line and the mutual inductance impedance between the newly constructed line and each energized line specifically includes: For each energized line, calculate the voltage drop and average current of the line based on its first and last coupled voltages and coupled currents. Based on the coupling voltage drop, average current and known zero-sequence parameters of the energized line, the mutual inductance impedance between the newly built line and each energized line is calculated. The zero-sequence impedance of the new line is calculated based on the response voltage and response current at the beginning of the new line and the mutual inductance obtained by solving.

4. The method according to claim 1, characterized in that, The newly constructed line differs from the existing energized line in at least one aspect, such as parallel length, parallel spacing, or conductor type, resulting in asymmetric line parameters.

5. The method according to claim 1, characterized in that, The frequency-dependent excitation signal is a high-amplitude frequency-dependent current signal with a frequency different from the power frequency.

6. A non-power-off testing device for parameters of a newly constructed parallel asymmetrical line in a corridor, characterized in that, The apparatus for implementing the method according to any one of claims 1 to 5 comprises: The sequence parameter acquisition unit is used to sequentially acquire the zero-sequence impedance and zero-sequence admittance of the existing n circuits in the same corridor using the sequence impedance parameter test method before the line is put into operation, where n≥1; after the n circuits are put into operation, in the case of newly built parallel lines on the same tower in the same corridor, the positive-sequence impedance and positive-sequence admittance of the newly built lines are acquired using the sequence impedance parameter test method. The excitation signal injection unit has its output terminal connected to the beginning of the new line to inject a different frequency excitation signal at the beginning of the new line. The synchronous measurement unit is used to short-circuit and ground the end of the newly built line, inject a different frequency excitation signal at the beginning of the newly built line, and synchronously measure the response voltage and current at the beginning of the newly built line, as well as the coupling voltage and coupling current at the beginning and end of all n energized lines, to obtain synchronous measurement data. The parameter calculation unit is used to calculate the zero-sequence impedance of the newly built line and the mutual inductance impedance between the newly built line and each of the existing lines based on the zero-sequence parameters of the n-circuit live lines and the synchronous measurement data; disconnect and suspend the end of the newly built line, inject a different frequency excitation signal at the beginning of the newly built line, measure the response voltage and current at the beginning of the newly built line, and calculate the zero-sequence admittance of the newly built line.

7. The apparatus according to claim 6, characterized in that, The synchronous measurement unit includes multiple voltage measurement channels and current measurement channels. Each channel is connected to the secondary side of the voltage transformer and current transformer at each measurement point via signal lines. The synchronous measurement unit has a synchronous sampling function to ensure the time consistency of all measurement data.

8. The apparatus according to claim 6, characterized in that, The excitation signal injection unit includes a frequency generator and a power amplifier. The frequency signal generated by the frequency generator is amplified and then injected into the head end of the newly built line.

9. The apparatus according to claim 6, characterized in that, The parameter calculation unit includes: The first calculation module is used to calculate the coupling voltage drop and average current of each live line based on the coupling voltage and coupling current at the beginning and end of each live line. The second calculation module is used to solve the mutual inductance impedance between the newly built line and each existing line based on the coupling voltage drop, average current, known zero-sequence impedance, and known coupling parameters between the existing lines. The third calculation module is used to calculate the zero-sequence impedance of the new line based on the response voltage and response current at the beginning of the new line and the mutual inductance impedance obtained by solving. The fourth calculation module is used to calculate the zero-sequence admittance of the new line after disconnecting and suspending the end of the new line and injecting a different frequency excitation signal at the beginning of the new line. This is based on the measured response voltage and current at the beginning of the new line.

10. The apparatus according to claim 6, characterized in that, The device also includes a display unit for displaying the calculated zero-sequence parameters of the newly built line and the mutual inductance impedance between the newly built line and each energized line.

11. A non-disconnect power supply testing system for parameters of newly constructed parallel asymmetrical lines in the same corridor, comprising: Computer-readable storage media and processors; The computer-readable storage medium is used to store executable instructions; The processor is used to read executable instructions stored in the computer-readable storage medium and execute the uninterrupted power supply test method for parameters of newly built parallel asymmetrical lines in the same corridor as described in any one of claims 1-5.

12. A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the uninterrupted power-off testing method for parameters of newly constructed parallel asymmetrical lines in the same corridor as described in any one of claims 1-5.

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