A Fitting Method and System for Line Tripping Simulation Curves

Abstract

The present invention discloses a fitting method for a line tripping simulation curve. The method includes: firstly, automatically extracting relevant parameters of a target line based on imported BPA data and calculating the current values before and after the line tripping; constructing a curve fitting for the line tripping, automatically fitting a simulation curve through a specified fault type, and generating simulation data in Comtrade format containing fault time series; finally, reading the simulation data through a stability control tester and replaying to check the accuracy of the tripping discrimination of the device, thus solving the technical problems such as the poor reliability of the stability control device caused by the fact that the criterion setting value design in the prior art strictly depends on manual setting, the large differences in line parameters in the actual system, and the inconsistent methods for setting value calculation.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system testing, and in particular, to a fitting method and system for a line tripping simulation curve. Background Art

[0002] The power system security and stability control system, simply referred to as the stability control system, is an important facility to ensure the safe and stable operation of the power system. In the regional stability control system, the stability control devices of each plant realize the transmission of information such as the power flow, operating status, and component faults of multiple components within the system through the power system communication network. When a serious fault occurs in the power grid, measures such as generator tripping or load shedding can be adopted to ensure the safe and stable operation of the power system. The design of the stability control strategy is based on various fault triggers, that is, first, it is determined that components such as lines trip, and then the stable control strategy is calculated based on system simulation analysis and executed by the stability control device. Therefore, determining the tripping of components such as lines is one of the important logics of the stability control device.

[0003] Traditional stability control relies on electrical quantities to judge line tripping, which is called the electrical quantity tripping criterion, and is mainly realized based on the fault process description method, mainly based on the following criteria:

[0004] (1) The sudden change in current ΔI ≥ ΔIs;

[0005] (2) The absolute value of the active power of the line before the accident P1 ≥ Ps1;

[0006] (3) The absolute value of the active power of the line after the accident P2 ≤ Ps2;

[0007] (4) The line current I2 after the accident ≤ Is2;

[0008] (5) Delay for Ts time.

[0009] Where: ΔIs, Ps1, Ps2, Is2, and Ts are all fixed values.

[0010] When all the above 5 conditions are satisfied, it is determined that the line trips.

[0011] The design of the above criterion fixed values strictly depends on manual setting. In the actual system, the line parameters vary greatly, and the methods for setting the fixed values are inconsistent. There is a need for a simulation method that can accurately simulate the line tripping curve to accurately verify the line tripping fixed values of the stability control device. Summary of the Invention

[0012] The technical problem to be solved by the present invention is: to provide a fitting method and system for a line tripping simulation curve, which, based on the actual parameters of the line, simulates the typical operating conditions and tripping types of the line, fits the tripping curve of the line, realizes accurate testing of the tripping criterion and fixed value setting of the stability control device, and improves the reliability of the stability control device.

[0013] The technical solution of the present invention is as follows:

[0014] A fitting method for the simulation curve of line tripping, the method comprising: first automatically extracting relevant parameters of the target line based on the imported BPA data, and calculating the current values before and after line tripping; constructing a curve fitting for line tripping, automatically fitting the simulation curve through the specified fault type, and generating simulation data in Comtrade format containing fault time series; finally reading the simulation data through a stability control tester to replay and verify the accuracy of the tripping discrimination of the device.

[0015] The method for automatically extracting relevant parameters of the target line from the imported BPA data is: importing the *.dat file of BPA simulation calculation and automatically parsing it, and extracting the length, admittance parameter and shunt reactance parameter of the line that is the same as the specified target line name.

[0016] When calculating the current values before and after line tripping: based on the extracted line parameters, calculate the charging current and charging power data of the line.

[0017] When constructing the curve fitting for line tripping, according to the set basic setting values, combined with the line parameters, the test terminal device fits and forms single-phase permanent fault, phase-to-phase fault, phase-to-phase grounding fault and three-phase grounding fault curves according to the fault generation module.

[0018] The method for constructing the curve fitting for line tripping includes:

[0019] Step 1: In the normal state, the three-phase current is given according to 6% of the rated current, the voltage is given according to the rated voltage, and the set state duration is 10 s;

[0020] Step 2: During the fault, according to the 78° fault angle and a grounding resistance of 3 Ω, calculate the output of the phase voltage and current during single-phase grounding, phase-to-phase grounding and phase-to-phase faults during the fault, and the fault lasts for 0.1 s; during the three-permanent fault, the angles of the phase voltage and phase current should satisfy smooth oscillation between 30° and 150°, and the phase voltage is less than 0.2 times the rated value;

[0021] Step 3: After the fault, according to the set post-trip current and power, the post-fault current given is equal to 0.8I cb ; the voltage is given according to the rated voltage, the current is given according to the value of 0.8I cb to give the current output quantity, and decays to 0 according to the exponent 0.8I cb e -t ;

[0022] Step 4: Generate the recorded wave data of Comtrade according to the time series and store it in the stability control device tester.

[0023] The method for reading simulation data through a stability control tester and replaying to verify the accuracy of the tripping discrimination of the verification device is as follows: Connect the stability control tester and the stability control device through a test cable; retrieve the generated comtrade recording data to form the D / A data output of three-phase voltage and current and convert it to the stability control device; scan and verify the specified intervals of the stability control device, and feedback the action results of the stability control device to the tester in the form of network messages to determine whether the results match the preset results. Pop-up warnings for the settings that do not meet the design requirements to remind the user to re-set and test again until the conditions are met.

[0024] A fitting system for the tripping simulation curve of a line, comprising:

[0025] Line parameter reading module: Import the *.dat file of BPA simulation calculation and automatically parse it to extract the length, admittance parameter, and shunt reactance parameter of the line that is the same as the specified target line name;

[0026] Data calculation module: Calculate the charging current and charging power data of the line based on the extracted line parameters;

[0027] Curve fitting module: Fit and form single-phase permanent fault, phase-to-phase fault, phase-to-phase grounding fault, and three-phase grounding fault curves according to the set basic settings in combination with the line parameters;

[0028] Data playback and test module: Read the simulation data and replay to verify the accuracy of the tripping discrimination of the verification device.

[0029] Advantages of the present invention:

[0030] The fitting method for the tripping simulation curve of the line proposed by the present invention can design a reliable curve fitting algorithm in combination with the line parameters, fully consider the influence of line CT saturation and charging current, accurately simulate the action behavior during various fault types of the line, improve the accuracy of the criterion design and setting of the stability control device, and ensure the reliable execution of the stability control strategy.

[0031] It solves the technical problems such as the poor reliability of the stability control device caused by the strict dependence of the criterion setting design on manual setting in the prior art, large differences in line parameters in the actual system, and inconsistent methods for setting calculation. Description of the drawings

[0032] Figure 1 It is a structural schematic diagram of the present invention.

[0033] Figure 2 It is a typical fitting curve proposed by the present invention. Detailed implementation manners

[0034] The present invention proposes a fitting method and system for the tripping simulation curve of a line, which includes:

[0035] Module 1: Line Parameter Reading Module

[0036] Import the *.dat file for BPA simulation calculation and automatically parse it to extract parameters such as the length, admittance parameter, and shunt reactance of the line that is consistent with the specified target line name.

[0037] Possible embodiments: For example, if the YongNAN50-NANN50 line is specified, the admittance parameter and shunt reactance parameter of the line are generally filled in the L and L+ cards of BPA. Taking the YongNAN50 line as an example, the L card and L+ card are as follows.

[0038] The module automatically parses the *.dat file, searches automatically with the keyword YongNAN50-NANN50, and extracts relevant parameters such as F6.5 (per-unit value of line-to-ground admittance), F4.1 (line length), and F5.0 (line shunt high reactance).

[0039] Module 2: Data Calculation Module

[0040] Based on the extracted line parameters, calculate key data such as line charging current and charging power.

[0041] Possible embodiments: For example, the per-unit value of line-to-ground admittance B / 2 of the YongNAN50-NANN50 line is 0.4982 (the line-to-ground conductance is generally considered to be 0), and the shunt reactance is 120 Mvar. The line charging current and charging power without considering the shunt reactance can be calculated by the following methods:

[0042]

[0043] Considering the shunt reactance S l , then:

[0044]

[0045] In the formula, Sb is the base capacity, which is defaulted to 100 MVA in BPA; Ub is the per-phase voltage base voltage, taking 525 kV / 1.732.

[0046] Q c = U n × I n × 0.01 × 10 -3 = 22.7 MVar (3)

[0047] Thus, the charging power of this line can be calculated as 22.7 MVar.

[0048] Module 3: Curve Fitting Module

[0049] According to the set basic setting values and combined with the line parameters, the test terminal device generates single-phase permanent faults, phase-to-phase faults, phase-to-phase grounding faults, and three-phase grounding faults according to the fault generation module, and the fitted line power curve is as Figure 2 shown. The fitting rules are as follows:

[0050] (1) In the normal state, the three-phase current is given according to 6% of the rated current (or refer to the user's manual setting value), the voltage is given according to the rated voltage, and the set state duration is 10 s, such as Figure 2 the initial section of

[0051] (2) During a fault, according to a 78° fault angle and a grounding resistance of 3 Ω, the output of the phase voltage and current during single-phase grounding, phase-to-phase grounding, and phase-to-phase faults during the fault is calculated, and the fault lasts for 0.1 s; during a three-phase permanent fault, the angles of the phase voltage and phase current should satisfy smooth oscillation between 30° and 150°, and the phase voltage is less than 0.2 times the rated value; such as Figure 2 the fault section of

[0052] (3) After the fault, according to the set post-trip current and power, considering the influence of the charging current, the post-fault current given is equal to 0.8I cb ; considering the influence of the CT saturation characteristic, the voltage is given according to the rated voltage, the current is given according to the value of 0.8I cb to give the current output quantity, and decays to 0 according to the exponent 0.8I cb e -t , such as Figure 2 the fault tripping section of

[0053] (4) Generate the comtrade recording data according to the time sequence and store it in the stability control device tester.

[0054] Module 4: Data playback and test module

[0055] According to the test requirements, connect the tester to the device through the test cable; retrieve the generated comtrade recording data, form the D / A data output of the three-phase voltage and current, and convert it to the stability control device; scan and check the specified interval of the stability control device, and feedback the action result of the stability control device to the tester in the form of a network message to determine whether its judgment result conforms to the preset result. Pop up a warning for the setting value that does not meet the design requirements, remind the user to re-set and test again until the conditions are met.

[0056] The fitting method of the line tripping simulation curve proposed by the present invention can design a reliable curve fitting algorithm in combination with line parameters, fully consider the influence of line CT saturation and charging current, accurately simulate the action behavior during various line fault types, and can carry out automatic verification of the line tripping criterion for the stability control device, improve the accuracy of the criterion design and setting value setting of the stability control device, and improve the test efficiency of the stability control system.

Claims

1. A fitting method for a circuit tripping simulation curve, characterized in that: The method includes: First, automatically extract the relevant parameters of the target line based on the imported BPA data, and calculate the current values before and after the line trip; construct a curve fitting for the line trip, automatically fit the simulation curve through the specified fault type, and generate simulation data in Comtrade format containing fault time series; finally, read the simulation data through a stability control tester and replay to verify the accuracy of the device trip discrimination; when constructing the curve fitting for the line trip, according to the set basic setting values, combined with the line parameters, the test terminal device fits and forms single-phase permanent fault, phase-to-phase fault, phase-to-phase grounding fault, and three-phase grounding fault curves according to the fault generation module; the method for constructing the curve fitting for the line trip includes: Step 1: In the normal state, the three-phase current is given according to 6% of the rated current, the voltage is given according to the rated voltage, and the set state duration is 10 s; Step 2: During the fault, calculate the output of the phase voltage and current for single-phase grounding, phase-to-phase grounding, and phase-to-phase faults during the fault according to a 78° fault angle and a grounding resistance of 3 Ω, and the fault lasts for 0.1 s; during the three-phase permanent fault, the angles of the phase voltage and phase current should satisfy smooth oscillation between 30° and 150°, and the phase voltage is less than 0.2 times the rated value; Step 3: After a fault, according to the set post-trip current and power, the post-fault current reference is equal to 0.8I cb ; the voltage is given as the rated voltage, and the current is given as the current output according to the value of 0.8I cb and decays exponentially to 0 according to the exponent 0.8I cb e -t ; Step 4: Generate the Comtrade waveform recording data according to the time series and store it in the stability control device tester.

2. The fitting method of a line tripping simulation curve according to claim 1, characterized in that: The method for automatically extracting the relevant parameters of the target line from the imported BPA data is: Import the *.dat file of the BPA simulation calculation and automatically parse it to extract the length, admittance parameters, and shunt reactance parameters of the line that is the same as the specified target line name.

3. A fitting method for a line tripping simulation curve according to claim 1, characterized in that: When calculating the current values before and after the line trip: Based on the extracted line parameters, calculate the line charging current and charging power data.

4. A fitting method for a line trip simulation curve according to claim 1, characterized in that: The method for reading the simulation data through a stability control tester and replaying to verify the accuracy of the device trip discrimination is: Connect the stability control tester to the stability control device through a test cable; retrieve the generated Comtrade waveform recording data to form the D / A data output of the three-phase voltage and current and convert it to the stability control device; Scan and verify the specified interval of the stability control device, and feedback the action result of the stability control device to the tester in the form of a network message, determine whether the result conforms to the preset result, pop up a warning for the setting values that do not meet the design requirements, remind the user to re-set, and test again until the conditions are met.

5. A fitting system for a line tripping simulation curve, characterized in that: Including: Line parameter reading module: Import the *.dat file of the BPA simulation calculation and automatically parse it to extract the length, admittance parameters, and shunt reactance parameters of the line that is the same as the specified target line name; Data calculation module: Based on the extracted line parameters, calculate the line charging current and charging power data; Curve fitting module: According to the set basic setting values combined with the line parameters, fit and form single-phase permanent fault, phase-to-phase fault, phase-to-phase grounding fault, and three-phase grounding fault curves; The method for constructing the curve fitting for the line trip includes: Step 1: In the normal state, the three-phase current is given according to 6% of the rated current, the voltage is given according to the rated voltage, and the set state duration is 10 s; Step 2: When a fault occurs, calculate the output of phase voltages and currents for single-phase grounding, phase-to-phase grounding, and phase-to-phase faults at a fault angle of 78° and a grounding resistance of 3Ω. The fault lasts for 0.1 s. When a three-permanent fault occurs, the angles of phase voltages and phase currents should smoothly oscillate between 30° and 150°, and the phase voltage should be less than 0.2 times the rated value. Step 3: After a fault, according to the set post-trip current and power, the post-fault current reference is equal to 0.8I cb ; the voltage is given as the rated voltage, and the current is given as the current output value according to 0.8I cb and decays to 0 according to the exponential 0.8I cb e -t ​ Step 4: Generate the oscillogram data of Comtrade according to the time sequence and store it in the stability control device tester. Data playback and test module: Read the simulation data and playback to verify the accuracy of the tripping discrimination of the device.

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