Multi-terminal fault location method based on wind farm collector line and transformer parameters

Abstract

This invention discloses a multi-terminal fault location method based on the parameters of wind farm collector lines and transformer substations. Belonging to the field of power system transmission engineering, it is mainly applied to the rapid location and maintenance of faults in the collector lines of wind power generation enterprises. This invention models the collector lines according to the collector line type and transformer substation parameters, determines the line impedance between adjacent components, calculates the voltage distribution of the T-junctions of all components in the entire collector line using transient current and voltage, determines whether the fault point is located between two wind turbines or between the beginning of the line and the first wind turbine, and calculates the impedance of the fault point from adjacent components based on the transient voltage and current on the low-voltage side of the wind turbine transformer substation and the beginning of the line, thereby achieving the purpose of determining the fault location.

Description

Technical Field

[0001] This invention relates to a multi-terminal fault location method based on the parameters of wind farm collector lines and transformer substations, belonging to the field of power system transmission engineering, and is mainly used for rapid location and maintenance of collector lines in wind power generation enterprises. Background Technology

[0002] In recent years, both the installed capacity and power generation of wind power have been increasing year by year. Due to the large distribution area and harsh environment of wind farm transmission lines, faults in these lines are frequent. After a fault occurs, it is necessary to inspect the transmission lines to pinpoint the fault location. Transmission lines are typically 5-15 km long, and this inspection work significantly increases the power outage time and on-site workload. To ensure the economical operation of wind farms, rapid troubleshooting and repair after an incident are crucial. Fault location technology for wind farm transmission lines is one of the important technical measures to ensure the safe, reliable, and economical operation of wind farms.

[0003] Accurate fault location can reduce the burden of line patrols and minimize economic losses. Accurate fault ranging can reduce the time maintenance personnel spend on line inspections, speed up line restoration, and reduce economic losses caused by power outages. Existing fault ranging methods for collector lines are single-end ranging; when the collector line is short-circuited through a transition resistor or the line parameters are inaccurate, the ranging error is large, resulting in poor performance in field applications. Therefore, an accurate fault ranging method for collector lines is needed. Summary of the Invention

[0004] The purpose of this invention is to address phase-to-phase faults in wind farm transmission lines. By using relevant electrical quantities, the location of the fault on the collector line is obtained. A multi-terminal ranging method for phase-to-phase faults based on the parameters of the wind farm collector line and transformer substation is proposed, which can accurately determine the specific location of the fault point.

[0005] The technical solution adopted by this invention to solve the above problems is: a multi-terminal fault location method based on the parameters of wind farm collector lines and transformer substations, characterized in that, impedance parameters are determined according to the type of collector line and the parameters of the transformer substation, and the collector line is modeled; transient fault information is collected and sent to the master station; the master station determines the fault location and the magnitude of the fault point transition resistance by calculating the voltage distribution of the entire collector line and solving the transient equation based on the collected fault information.

[0006] Furthermore, based on the model parameters of the collector line and the locations of all wind turbines, the line impedance from the T-junction of the first wind turbine to the main station side is determined; based on the model parameters of the collector line and the locations of two adjacent wind turbines, the line impedance between two adjacent wind turbines is determined; based on the nameplate parameters of the transformer substation and the parameters of the downlead of the T-junction section of the transformer substation, the impedance from the transformer substation to the T-junction is determined. Based on the above impedances, the collector line and its connected transformer substations are modeled to determine the impedances between each component.

[0007] Furthermore, after a fault in the collector line, the transient voltage and current vectors of the line and all wind turbines, as well as the transient current and voltage vectors of the collector line on the main station side, are collected. The collected voltage and current vectors are then transmitted to the main station via the communication channel between the wind turbines and the main station. Synchronization at different sampling points relies on the station clock. Based on the transient voltage and current of each component at the same time section, the main station determines the voltage distribution (UT) at each T-junction and the line head-end of the entire collector line. s U k +I k Z k The fault point is located between the two nodes with the lowest voltage.

[0008] Furthermore, the main station can calculate the voltage distribution of the entire collection line using the transient voltage and current vectors of each transformer, thus determining that the fault point is located between the T-junctions of two adjacent wind turbines. The line current upstream of the fault point can be obtained by summing the current at the beginning of the line and the currents of each wind turbine upstream of the fault point, i.e., I. sk The downstream current is the sum of the currents of all fans after the fault point, i.e., I. fk The transient current and voltage of the two wind turbines can be directly collected, i.e., U k I k U k-1 I k-1 The impedance of the fan box transformer and its lead wires (Z) k The impedance (ΔZk) between the two wind turbine T-junctions is used as the modeling parameter. Solving the transient equations determines the line parameters and transition resistance to the main station, thus revealing the location of the fault point.

[0009] Furthermore, the main station can calculate the voltage distribution across the entire transmission line to determine the fault location between the beginning of the line and the T-junction of the first wind turbine. The current from the fault point to the T-junction of that wind turbine is obtained by summing the currents of all wind turbines, i.e., If. f1 The current from the fault point to the main transformer side is the transient current of the collector line, i.e., I. s The transient current and voltage at the first wind turbine and the beginning of the line can be directly collected, i.e., U s I sU1, I1. The impedance of the wind turbine transformer box and its lead wires (Z1) and the impedance between the T-junction of the first wind turbine and the main transformer side (ΔZ1) are used as modeling parameters. Solving the transient equations determines the line parameters and transition resistance from the fault point to the main station side, thus obtaining the location of the fault point.

[0010] Compared with the prior art, the present invention has the following advantages and effects: The present invention models the collector line according to the collector line model and transformer parameters, determines the line impedance between adjacent components, calculates the voltage distribution of the T-junction of each component in the entire collector line through transient current and voltage of each component, determines that the fault point is located between two wind turbines or between the beginning of the line and the first wind turbine, and determines the impedance of the fault point from the adjacent components by solving the transient voltage and current of the low-voltage side of the wind turbine transformer and the beginning of the line, so as to accurately determine the specific location of the fault point. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the phase-to-phase fault multi-terminal ranging method in an embodiment of the present invention. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0013] Example.

[0014] In this embodiment, the multi-terminal fault location method based on wind farm collector lines and transformer parameters is as follows:

[0015] Based on the model of the collector line and the parameters of the transformer substation, the impedance parameters are determined, and the collector line is modeled. Transient fault information is collected and sent to the master station. Based on the collected fault information, the master station calculates the voltage distribution of the entire collector line and solves the transient equations to determine the location of the fault point and the magnitude of the transition resistance at the fault point.

[0016] Based on the model parameters of the collector line and the locations of all wind turbines, determine the line impedance from the T-junction of the first wind turbine to the main station side; based on the model parameters of the collector line and the locations of two adjacent wind turbines, determine the line impedance between two adjacent wind turbines; based on the nameplate parameters of the transformer substation and the parameters of the downlead of the T-junction section of the transformer substation, determine the impedance from the transformer substation to the T-junction. Model the collector line and its connected transformer substations based on the above impedances to determine the impedance between each component. For example... Figure 1 As shown, the impedance △Zk (including △Z1) is determined.

[0017] After a fault in the collector line, transient voltage and current vectors of the line and all wind turbines, as well as transient current and voltage vectors of the collector line at the main station, are collected. The collected voltage and current vectors are then transmitted to the main station via the communication channel between the wind turbines and the main station. Synchronization of different sampling points relies on the station clock. Based on the transient voltage and current of each component at the same time section, the main station determines the voltage distribution (UT) at each T-junction and the line head-end of the entire collector line. s U k +I k Z k The fault point is located between the two nodes with the lowest voltage. For example... Figure 1 As shown, the fault point is determined to be located between the two wind turbine T-junctions or between the beginning of the line and the first wind turbine T-junction.

[0018] For example, the main station calculates the voltage distribution of the entire collection line using the transient voltage and current vectors of each transformer, determining that the fault point is located between two adjacent wind turbine T-junctions. Figure 1 As shown, the line current upstream of the fault point can be obtained by summing the current at the beginning and the current of each fan upstream of the fault point, i.e., I sk The downstream current is the sum of the currents of all fans after the fault point, i.e., I. fk The transient current and voltage of the two wind turbines can be directly collected, i.e., U k I k U k-1 I k-1 The impedance of the fan box transformer and its lead wires (Z) k The impedance (ΔZk) between the two wind turbine T-junctions is used as the modeling parameter. Solving the transient equations determines the line parameters and transition resistance to the main station, thus revealing the location of the fault point.

[0019] For example, the main station can calculate the voltage distribution of the entire collection line to determine that the fault point is located between the beginning of the line and the T-junction of the first wind turbine. Figure 1 As shown, the current from the fault point to the T-junction of the wind turbine is obtained by summing the currents of all wind turbines, i.e., I. f1 The current from the fault point to the main transformer side is the transient current of the collector line, i.e., I. s The transient current and voltage at the first wind turbine and the beginning of the line can be directly collected, i.e., U s I s U1, I1. The impedance of the wind turbine transformer box and its lead wires (Z1) and the impedance between the T-junction of the first wind turbine and the main transformer side (ΔZ1) are used as modeling parameters. Solving the transient equations determines the line parameters and transition resistance from the fault point to the main station side, thus obtaining the location of the fault point.

[0020] A transmission line at a wind farm experienced a fault. Some parameters of the faulty line are as follows: Figure 1 As shown.

[0021] When the fault point is located at fan F k and F k-1 When a fault occurs between and through a transition resistor, the main station calculates the voltage distribution of the entire collector line to determine that the fault point is located in the adjacent F. k and F k-1 Between the two fans, the voltage at the T-junction is calculated, and the transient equation satisfies:

[0022] ,

[0023] Z can be obtained by solving the simultaneous equations. fk Z sk R k Determine the location of the fault and the transition resistance.

[0024] in:

[0025] △Zk represents fan F k T-junction to fan F k-1 The per-unit impedance between T-junctions;

[0026] Z fk For wind turbine F k The per-unit impedance between the T-junction and the fault point;

[0027] Z sk For wind turbine F k-1 The per-unit impedance between the T-junction and the fault point;

[0028] R k This is the per-unit value of the transition resistance at the fault point;

[0029] Z k For wind turbine F k The per-unit impedance of the transformer and the impedance per lead from the T-junction;

[0030] Z k-1 For wind turbine F k-1 The per-unit impedance of the transformer and the impedance per lead from the T-junction;

[0031] U k For wind turbine F k The per-unit value of the low-voltage side transient voltage;

[0032] U k-1 For wind turbine F k-1 The per-unit value of the low-voltage side transient voltage;

[0033] I k For wind turbine F k The per-unit value of the low-voltage side transient current;

[0034] I k-1 For wind turbine F k-1The per-unit value of the low-voltage side transient current;

[0035] I fk For wind turbine F k The per-unit value of the fault current from the T-junction to the fault point conductor;

[0036] I sk For wind turbine F k-1 The per-unit value of the fault current from the T-junction to the fault point conductor;

[0037] I s This is the per-unit value of the transient current at the beginning of the line.

[0038] When the fault point is located between the beginning of the line and the first wind turbine, the main station determines that the fault point is located between the beginning of the line and the first wind turbine at that end by calculating the voltage distribution of the entire collection line. The voltage at the T-junction is calculated, and the transient equation satisfies:

[0039] ,

[0040] Z can be obtained by solving the simultaneous equations. f1 Z s1 R1, determine the location of the fault.

[0041] in:

[0042] △Z1 is the per-unit impedance value between the T-junction of wind turbine F1 and the main transformer side;

[0043] Z f1 This is the per-unit impedance value between the T-contact of fan F1 and the fault point;

[0044] Z s1 The per-unit impedance value between the main transformer side and the fault point;

[0045] R1 is the per-unit value of the transition resistance at the fault point;

[0046] Z1 is the per-unit impedance of the transformer box for fan F1 and the impedance per lead from the lead wire to the T-connector;

[0047] Z s The per-unit value of the impedance from the main transformer side to the T-junction;

[0048] U1 is the per-unit value of the low-voltage side transient voltage of fan F1;

[0049] I1 is the per-unit value of the low-pressure side transient current of fan F1;

[0050] I f1 This is the per-unit value of the fault current in the conductor from the T-contact of fan F1 to the fault point;

[0051] U s Per-unit value of transient voltage on the low-voltage side of the main transformer;

[0052] I s I s1 This is the per-unit value of the transient current at the beginning of the line.

[0053] Any content not described in detail in this specification is prior art known to those skilled in the art.

[0054] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the scope of protection of the present invention. Any modifications and refinements made by those skilled in the art without departing from the concept and scope of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A multi-terminal fault location method based on parameters of wind farm collector lines and transformer substations, characterized in that, The impedance parameters are determined based on the parameters of the collector line and the transformer substation, and the collector line is modeled. Based on the model parameters of the collector line and the location of the first wind turbine at the beginning, determine the line impedance from the T-junction of the first wind turbine at the beginning to the main station side; based on the model parameters of the collector line and the locations of two adjacent wind turbines, determine the line impedance between two adjacent wind turbines; based on the nameplate parameters of the transformer substation and the parameters of the lead-down wire of the T-junction of the transformer substation, determine the impedance from the transformer substation to the T-junction; based on the above impedances, model the collector line and its connected transformer substations, and determine the impedance between each component. The transient fault information is collected and sent to the master station. Based on the collected fault information, the master station calculates the voltage distribution of the entire line and solves the transient equations to determine the location of the fault point and the magnitude of the transition resistance of the fault point. When the fault point is located at fan F k and F k-1 When a fault occurs between and through a transition resistor, the main station calculates the voltage distribution of the entire collector line to determine that the fault point is located in the adjacent F. k and F k-1 Between the two fans, the voltage at the T-junction is calculated, and the transient equation satisfies: ， Z can be obtained by solving the simultaneous equations. fk Z sk R k Determine the location of the fault and the transition resistance; in: △Z k For wind turbine F k T-junction to fan F k-1 The per-unit impedance between T-junctions; Z fk For wind turbine F k The per-unit impedance between the T-junction and the fault point; Z sk For wind turbine F k-1 The per-unit impedance between the T-junction and the fault point; R k This is the per-unit value of the transition resistance at the fault point; Z k For wind turbine F k The per-unit impedance of the transformer and the impedance per lead from the T-junction; Z k-1 For wind turbine F k-1 The per-unit impedance of the transformer and the impedance per lead from the T-junction; U k For wind turbine F k The per-unit value of the low-voltage side transient voltage; U k-1 For wind turbine F k-1 The per-unit value of the low-voltage side transient voltage; I k For wind turbine F k The per-unit value of the low-voltage side transient current; I k-1 For wind turbine F k-1 The per-unit value of the low-voltage side transient current; I fk For wind turbine F k The per-unit value of the fault current from the T-junction to the fault point conductor; I sk For wind turbine F k-1 The per-unit value of the fault current from the T-junction to the fault point conductor; I s This is the per-unit value of the transient current at the beginning of the line; When the fault point is located between the beginning of the line and the first wind turbine, the main station determines that the fault point is located between the beginning of the line and the first wind turbine at that end by calculating the voltage distribution of the entire collection line. The voltage at the T-junction is calculated, and the transient equation satisfies: ， Z can be obtained by solving the simultaneous equations. f1 Z s1 R1, determine the location of the fault; in: △Z1 is the per-unit impedance value between the T-junction of wind turbine F1 and the main transformer side; Z f1 This is the per-unit impedance value between the T-contact of fan F1 and the fault point; Z s1 The per-unit impedance value between the main transformer side and the fault point; R1 is the per-unit value of the transition resistance at the fault point; Z1 is the per-unit impedance of the transformer box for fan F1 and the impedance per lead from the lead wire to the T-connector; Z s The per-unit value of the impedance from the main transformer side to the T-junction; U1 is the per-unit value of the low-voltage side transient voltage of fan F1; I1 is the per-unit value of the low-pressure side transient current of fan F1; I f1 This is the per-unit value of the fault current in the conductor from the T-contact of fan F1 to the fault point; U s Per-unit value of transient voltage on the low-voltage side of the main transformer; I s I s1 This is the per-unit value of the transient current at the beginning of the line.

2. The method for multi-terminal fault location based on wind farm collector lines and transformer parameters according to claim 1, characterized in that, After a fault occurs in the collector line, the transient voltage and current vectors of the line and all wind turbines, as well as the transient current and voltage vectors of the collector line on the main station side, are collected and transmitted to the main station via the communication channel between the wind turbine and the main station. Synchronization of different sampling points relies on the station clock. The main station determines the voltage distribution of each T-connector and the beginning of the line based on the transient voltage and current of each component at the same time section. The fault point is located between the two nodes with the lowest voltage.

3. The multi-terminal fault location method based on wind farm collector lines and transformer parameters according to claim 2, characterized in that, When the main station calculates the voltage distribution of the entire collection line through the transient voltage and current vector of each transformer and determines that the fault point is located between the T-junctions of two adjacent wind turbines, the line current before the fault point is obtained by the sum of the current at the beginning and the current of each wind turbine before the fault point, and the line current after the fault point is the result of the sum of the currents of each wind turbine after the fault point. The transient current and voltage of the two wind turbines can be directly collected; the transient equations are solved based on the modeling parameters to determine the line parameters and transition resistance from the fault point to the main station, and the location of the fault point is obtained.

4. The multi-terminal fault location method based on wind farm collector lines and transformer parameters according to claim 2, characterized in that, When the main station determines that the fault point is located between the beginning of the line and the T-junction of the first wind turbine by calculating the voltage distribution of the entire collection line, the current from the fault point to the T-junction of the wind turbine is obtained by summing the currents of all wind turbines, and the current from the fault point to the main transformer side is the transient current of the collection line; the transient current and voltage of the first wind turbine and the beginning of the line can be directly collected. Based on the modeling parameters, the transient equations are solved to determine the line parameters and transition resistance from the fault point to the main station, thus obtaining the location of the fault point.

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