CN113740791A - Distribution network fault indicator wave recording accuracy testing method and system - Google Patents
Distribution network fault indicator wave recording accuracy testing method and system Download PDFInfo
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Abstract
The invention provides a method for testing wave recording accuracy of a distribution network fault indicator, which comprises the following steps: inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies; comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error; the system simulation model is constructed by three-phase modeling of a typical power distribution network simulated by the neutral point arc suppression coil grounding system and set circuit and element parameters; the influence of sampling frequency of various fault conditions on fault recording errors of the fault indicator is reflected, and the operation effect of the power distribution network fault identification and positioning equipment is further improved.
Description
Technical Field
The invention belongs to the technical field of distribution network equipment detection, and relates to a method and a system for testing wave recording accuracy of a distribution network fault indicator.
Background
At present, most of medium and low voltage distribution networks adopt a neutral point indirect grounding system, namely a low current grounding system, and more than 80% of faults in the operation of the distribution network system are counted as single-phase grounding faults or related faults caused by the single-phase grounding faults according to incomplete statistics. With the continuous improvement of the requirements on the fault identification and positioning accuracy of the power distribution network, the transient recording type power distribution line fault indicator for improving the fault identification and positioning accuracy through three-phase fault recording synthesis is widely applied. When a single-phase earth fault occurs to a neutral point through an arc suppression coil grounding system (NES), the electric fault quantity such as voltage, current and the like is not obviously changed, and the wave recording precision of the fault wave recording device directly influences the accuracy of fault identification and positioning.
At present, students optimize the acquisition of fault information of a fault indicator on one hand, and construct a special detection system to detect the functions and performances of various fault indicators in order to ensure that the fault indicator of a power distribution network can safely, stably and reliably operate on the other hand. If a novel online monitoring device for a power distribution network is designed, the current of each outgoing line is monitored by using a Rogowski coil, and a voltage sensor based on space capacitance voltage division collects voltage, so that high-precision fault recording is realized, and the starting sensitivity of the wave recording and the transient signal collection precision are improved; some provide a mode of sending a synchronous packet to the acquisition unit through the collection unit, and some provide an improved master station broadcast time synchronization method which decomposes a time synchronization message into a clock message and a time synchronization command, and the like, so as to realize three-phase synchronous wave recording. The current design scheme of the fault indicator detection platform can be divided into three types: the method comprises the following steps of performing a field manual test, checking the running condition of a fault indicator system by performing a manual single-phase grounding test on a practical 10kV low-current grounding system, and further analyzing the effectiveness of the fault indicator system; physical dynamic simulation, namely establishing a fault simulation unit, a power supply, a line and a load model by a physical model equivalent method to form a distribution network model; the digital real-time simulation device consists of a digital real-time simulator, a simulation background system and a large-current and high-voltage real-time generating device, and can simulate different fault conditions of a distribution line.
And displaying field operation data, wherein the operation effect of the fault indicator detected through network access has a certain difference with design data, and the accuracy of the line selection positioning device and the fault indicator for positioning the single-phase earth fault is still not high. In order to test whether the fault indicator can reliably complete fault recording and fault positioning, a test detection means for perfecting fault recording quality control on the equipment is needed.
Disclosure of Invention
The invention provides a method for testing wave recording accuracy of a distribution network fault indicator, which aims to solve the problems that the operation effect of the fault indicator which is displayed by the existing field operation data and is detected by network access has a certain difference with the design data, and the positioning accuracy of a line selection positioning device and the fault indicator to a single-phase earth fault is still low, and comprises the following steps:
inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies;
comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error;
the simulation model of the neutral point arc suppression coil grounding system is constructed by three-phase modeling of a typical power distribution network simulated by the neutral point arc suppression coil grounding system and set circuit and element parameters.
Preferably, the step of inputting a plurality of simulation time steps and influencing factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies includes:
simulating each fault type of single-phase grounding of the power distribution network based on the value of the influence factor, and respectively obtaining transient zero-sequence current data of a plurality of sampling frequencies of preset data points in a sampling time period according to a plurality of simulation time step lengths corresponding to the single-phase grounding faults;
and drawing a transient zero-sequence current waveform with a plurality of sampling frequencies based on the transient zero-sequence current data with a plurality of sampling frequencies of preset data points in the sampling time period.
Preferably, the influencing factors include: and (3) presetting single-phase earth fault transition resistance, fault distance and fault phase angle in a value range.
Preferably, the comparing the transient zero-sequence current waveform data based on the preset standard sampling frequency with the transient zero-sequence current waveform data based on the sampling frequency without the standard sampling frequency in different frequencies to obtain the transient peak error includes:
based on the condition that the maximum transient peak value error of the waveform under each sampling frequency and the waveform of the standard sampling frequency cannot be larger than a preset value, comparing and calculating transient zero-sequence current waveform data of each fault line under each sampling frequency under different transition resistors, different fault distances and different fault phase angles to obtain the maximum transient peak value instantaneous error;
and drawing a line graph about the sampling frequency and the maximum transient peak instantaneous error based on the maximum transient peak instantaneous errors under different transition resistances, different fault distances and different fault phase angles to obtain a transient peak error trend.
Preferably, the maximum transient peak transient error is calculated as follows:
where ERROR is the maximum transient peak instantaneous ERROR, yitpIs a transient peak value y at a sampling frequency of i (kHz)10tpIs a transient peak value when the sampling frequency is the standard sampling frequency.
Preferably, the plotting a line graph about the sampling frequency and the maximum transient peak instantaneous error based on the maximum transient peak instantaneous error at different transition resistances, different fault distances, and different fault phase angles to obtain a transient peak error trend includes:
and respectively changing the transition resistance, the fault distance and the fault phase angle, and sequentially increasing the sampling frequency to obtain a linear graph in which the instantaneous errors of the maximum transient peak value all show a descending trend along with the increase of the sampling frequency and the descending trend tends to be stable when the preset sampling frequency is reached.
Preferably, the line and component parameters include: power transmission line, power supply parameters, transformer parameters and load parameters;
the transmission line comprises: five-loop outgoing lines, two overhead lines, two cables and an overhead cable are mixed to be outgoing.
Preferably, the three-phase modeling is carried out on the simulation model of the system with the neutral point grounded through the arc suppression coil by utilizing MATLAB/Simulink software to simulate a typical power distribution network for the system with the neutral point grounded through the arc suppression coil.
Based on the same conception, the invention provides a wave recording accuracy testing system for a distribution network fault indicator, which comprises: a waveform data module and an error solving module;
the waveform data module is used for inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies;
the error solving module is used for comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error;
the simulation model of the neutral point arc suppression coil grounding system is constructed by three-phase modeling of a typical power distribution network simulated by the neutral point arc suppression coil grounding system and set circuit and element parameters.
Preferably, the waveform data module includes: a transient zero-sequence current data submodule and a waveform submodule;
the transient zero-sequence current data submodule is used for simulating each fault type of single-phase grounding of the power distribution network based on values of influence factors, and obtaining transient zero-sequence current data with a plurality of sampling frequencies of preset data points in a sampling time period according to a plurality of simulation time step lengths corresponding to the single-phase grounding faults;
the waveform submodule is used for drawing the transient zero-sequence current waveform with multiple sampling frequencies based on the transient zero-sequence current data with multiple sampling frequencies of preset data points in the sampling time period.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention provides a method for testing wave recording accuracy of a distribution network fault indicator, which comprises the following steps: inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies; comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error; the system simulation model is constructed by three-phase modeling of a typical power distribution network simulated by the neutral point arc suppression coil grounding system and set circuit and element parameters; reference data are provided for the detection standard of the fault indicator, the influence of sampling frequency of various fault conditions on fault recording errors of the fault indicator is reflected, and the operation effect of power distribution network fault identification and positioning equipment is further improved.
Drawings
FIG. 1 is a flow chart of a method provided by the present invention;
fig. 2 is a model diagram of a system for grounding a power distribution network via arc suppression coils according to an embodiment of the present invention;
fig. 3 is a waveform diagram of zero sequence current of each line of the power distribution network according to an embodiment of the present invention;
FIG. 4 is a graph illustrating the effect of different transition resistance down-sampling frequencies on recording errors according to an embodiment of the present invention;
FIG. 5 is a graph illustrating the effect of downsampling frequencies for different fault distances on recording errors according to an embodiment of the present invention;
FIG. 6 is a graph illustrating the effect of downsampling frequency of different fault phase angles on recording error according to an embodiment of the present invention;
fig. 7 is a system configuration diagram provided by the present invention.
Detailed Description
The embodiments of the present invention will be further explained with reference to the drawings.
Example 1:
the invention provides a method for testing wave recording accuracy of a distribution network fault indicator, which takes a single-phase ground fault indicator of a distribution network in a mode that a neutral point is grounded through an arc suppression coil as a research object, provides a wave recording error calculation method suitable for detecting the wave recording quality of a transient wave recording type fault indicator of the distribution network, analyzes the influence rule of the sampling frequency of a wave recording device on the fault recording error of the fault indicator, provides reference data for the detection standard of the fault indicator, further improves the operation effect of fault identification and positioning equipment of the distribution network, and is introduced by combining with a method flow chart of figure 1, and specifically comprises the following steps:
step 1: inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies;
step 2: comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error;
wherein, the step 1: inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of a neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies, and the method specifically comprises the following steps:
and (3) carrying out three-phase modeling on a typical power distribution network simulated by a neutral point arc suppression coil grounding system by using MATLAB/Simulink software, setting line and element parameters, and selecting different fault conditions to carry out a single-phase grounding fault simulation test to obtain the transient zero-sequence current of each line after the fault occurs.
The grounding mode of the power distribution network is that a neutral point is grounded through an arc suppression coil, the model is introduced by combining a power distribution network grounding system model diagram of fig. 2 through the arc suppression coil, the model comprises five-loop outgoing lines, two overhead lines, two cables and an overhead cable mixed outgoing line, and line parameters mainly comprise power transmission lines, power supply parameters, transformer parameters and load parameters.
Analyzing single-phase earth fault influence factors such as transition resistance, fault distance, fault phase angle and the like, and simulating single-phase earth faults of the power distribution network under different fault conditions;
determining typical fault conditions according to single-phase earth fault influence factors such as transition resistance, fault distance, fault phase angle and the like, and changing the values of the influence factors according to fault occurrence conditions in actual engineering. R is single-phase earth fault transition resistance, and the value range of R is 0-1000 omega; l is a fault distance, and the value range is 0-25 km; the phase angle range of the phase voltage at the fault moment is 0 degree, 30 degrees, 60 degrees and 90 degrees.
And changing the sampling frequency by setting the step length of the simulation time in a sampling option of an oscilloscope in the MATLAB to obtain zero sequence current recording data under different sampling frequencies. And assuming that the fault line transient zero-sequence current waveform sequence with the sampling frequency of the ith kHz contains n data points in the sampling time period, and performing linear interpolation on the transient zero-sequence current waveform with the sampling frequency lower than the standard sampling frequency to obtain the data points which are the same as the standard waveform sequence.
Step 2: transient zero sequence current waveform data under the standard sampling frequency based on presetting and transient zero sequence current waveform data under the sampling frequency that does not contain standard sampling frequency in the different frequencies are compared, obtain transient peak value error, specifically include:
and comparing the transient peak value of the zero-sequence current by taking the zero-sequence current waveform of the fault line with the sampling frequency of 10kHz as a standard waveform and taking the current waveforms acquired under other sampling frequencies as comparison waveforms, thereby obtaining the transient peak value error between the waveform and the standard waveform under any sampling frequency. The maximum peak instantaneous error in the transient state performance of the fault recording of the national power grid distribution line fault indicator network access detection outline is not more than 10%. The zero sequence current waveform of the fault line with the sampling frequency of 10kHz is used as a standard waveform sequence, and the calculation method formula of the maximum peak instantaneous error is as follows:
because the error value is too large when the sampling frequency is 1kHz as seen from the data consulted and the simulation results. Here, the data with the sampling frequency of 1kHz is not put on;
yitp: the sampling frequency is a transient peak value under i (kHz); y is10tp: the sampling frequency is the transient peak at 10 kHz.
In the embodiment, a single-phase earth fault simulation test is carried out by establishing a neutral point arc suppression coil grounding system simulation typical power distribution network model in MATLAB/Simulink software. A single-phase earth fault simulation model of the power distribution network is shown in the figure.
The simulation model of the embodiment comprises a power supply model, a power transmission line model, a transformer model, a load and a single-phase groundingA fault setting model. The system comprises a 5-loop outgoing line, wherein L1 is a 15km overhead line, L2 is a 25km overhead line, L3 is a 12km cable, L4 is an 8km cable, and L5 is a mixed outgoing line of 7km overhead line and 5km cable; the system power supply voltage grade is 10 kV; the transition resistance is R; the load selects three-phase series RLC modules, and the active power is 1MW, 1.5MW, 0.8MW, 0.6MW and 0.8MW respectively. The line adopts a distributed parameter model, and the parameter values are shown in table 1; the arc suppression coil adopts 8% of compensation degree and is combined
The arc suppression coil inductance was calculated to be 0.7569H.
Table 1 transmission line parameters
Fig. 3 shows a waveform of zero-sequence current of each line under a condition of a typical single-phase metallic ground fault, in which the transient zero-sequence current of the faulty line is opposite to the transient zero-sequence current of the non-faulty line, and the amplitude of the transient zero-sequence current of the faulty line is greater than that of any non-faulty line.
And analyzing the influence factors of the single-phase earth faults such as the transition resistance, the fault distance, the fault phase angle and the like, and simulating the single-phase earth faults of the power distribution network under different fault conditions. Changing the values of the influence factors according to the fault occurrence conditions in the actual engineering: r is single-phase earth fault transition resistance, and the value range of R is 0-1000 omega; l is a fault distance, and the value range is 0-25 km; the value ranges of phase voltage phase angles at the fault time are 0 degrees, 30 degrees, 60 degrees and 90 degrees, zero sequence current waveforms of fault lines under various fault conditions are obtained, and the introduction is carried out by combining the zero sequence current waveform diagrams of all lines of the power distribution network in fig. 3.
In order to ensure that the fault signal of 10kHz can be selected as the standard for simulating the sampling frequency of the fault indicator of the fault signal most truly, the influence rule of different sampling frequencies on the transient recording error under the typical fault condition is analyzed. And assuming that the sampling frequency is ith kHz, n data points are contained in the time segment of each cycle, obtaining a fault line transient zero-sequence current waveform sequence under the sampling frequency, and performing linear interpolation on a transient zero-sequence current waveform under the standard sampling frequency to obtain the number of data points which is the same as that of the standard waveform sequence.
The maximum peak instantaneous error in the transient state performance of the fault recording of the national power grid distribution line fault indicator network access detection outline is not more than 10%. And sampling a fault line zero-sequence current waveform with the frequency of 10kHz as a standard waveform sequence. The error calculation method compares the transient process peak value of the zero sequence current fault waveform under different sampling frequencies with the transient state peak value of the zero sequence current waveform under the standard sampling frequency, and the maximum peak value transient error calculation method has the following formula:
yitp: the sampling frequency is the transient peak value y under i (kHz)10tp: the sampling frequency is the transient peak at 10 kHz.
The influence of the downsampling frequencies of different transition resistances on the recording error is obtained through simulation calculation, and the influence is shown in fig. 4. It can be seen that the wave recording errors all show a descending trend along with the increase of the sampling frequency under different transition resistances. When the sampling frequency reaches 6kHz and under the condition of various transition resistances, the transient peak value error is below 10 percent; when the sampling frequency reaches above 6kHz, the transient peak value error tends to be stable.
Through simulation calculation, the influence of the sampling frequency at different fault distances on the recording error is obtained as shown in fig. 5, and it can be seen that the recording error shows a descending trend along with the increase of the sampling frequency at different fault distances.
Through simulation calculation, the influence of the downsampling frequency of different fault phase angles on the recording error is obtained as shown in fig. 6, and it can be seen that the transient amplitude error shows a descending trend along with the increase of the sampling frequency under different fault phase angles, and the reduction of the transient amplitude error tends to be saturated after the sampling frequency is increased to 6 kHz.
Example 2:
based on the same concept, the invention provides a system for testing the wave recording accuracy of a distribution network fault indicator, which is introduced by combining the system structure diagram of fig. 7, and specifically comprises the following steps:
a waveform data module and an error solving module;
the waveform data module is used for inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies;
the error solving module is used for comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error;
the simulation model of the neutral point arc suppression coil grounding system is constructed by three-phase modeling of a typical power distribution network simulated by the neutral point arc suppression coil grounding system and set circuit and element parameters.
The waveform data module includes: a transient zero-sequence current data submodule and a waveform submodule;
the transient zero-sequence current data submodule is used for simulating each fault type of single-phase grounding of the power distribution network based on values of influence factors, and obtaining transient zero-sequence current data with a plurality of sampling frequencies of preset data points in a sampling time period according to a plurality of simulation time step lengths corresponding to the single-phase grounding faults;
the waveform submodule is used for drawing the transient zero-sequence current waveform with multiple sampling frequencies based on the transient zero-sequence current data with multiple sampling frequencies of preset data points in the sampling time period.
The error solving module comprises: a transient peak error submodule and a transient peak error trend submodule;
the transient peak error submodule is used for comparing and calculating transient zero-sequence current waveform data of each fault line under each sampling frequency under different transition resistors, different fault distances and different fault phase angles to obtain a maximum transient peak instantaneous error on the basis of the condition that the maximum transient peak error of the waveform under each sampling frequency and the waveform of the standard sampling frequency cannot be larger than a preset value;
and the transient peak error trend submodule is used for drawing a line graph about the sampling frequency and the maximum transient peak instantaneous error based on the maximum transient peak instantaneous error under different transition resistances, different fault distances and different fault phase angles to obtain a transient peak error trend.
The transient peak error trend submodule, comprising: a line graph element;
the linear graph unit is used for respectively changing the transition resistance, the fault distance and the fault phase angle, sequentially increasing the sampling frequency to obtain a linear graph in which the maximum transient peak instantaneous error shows a descending trend along with the increase of the sampling frequency and the descending trend tends to be stable when the preset sampling frequency is reached.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may 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, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may 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, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.
Claims (10)
1. A wave recording accuracy testing method for a distribution network fault indicator is characterized by comprising the following steps:
inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies;
comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error;
the simulation model of the neutral point arc suppression coil grounding system is constructed by three-phase modeling of a typical power distribution network simulated by the neutral point arc suppression coil grounding system and set circuit and element parameters.
2. The method of claim 1, wherein the step of inputting a plurality of simulation time steps and influencing factors corresponding to the single-phase earth fault of the power distribution network to be simulated into a pre-constructed simulation model of the arc suppression coil grounding system with neutral points, so as to obtain transient zero-sequence current waveform data under different sampling frequencies, comprises:
simulating each fault type of single-phase grounding of the power distribution network based on the value of the influence factor, and respectively obtaining transient zero-sequence current data of a plurality of sampling frequencies of preset data points in a sampling time period according to a plurality of simulation time step lengths corresponding to the single-phase grounding faults;
and drawing a transient zero-sequence current waveform with a plurality of sampling frequencies based on the transient zero-sequence current data with a plurality of sampling frequencies of preset data points in the sampling time period.
3. The method of claim 2, wherein the influencing factors comprise: and (3) presetting single-phase earth fault transition resistance, fault distance and fault phase angle in a value range.
4. The method of claim 3, wherein the comparing the transient zero-sequence current waveform data based on the preset standard sampling frequency with the transient zero-sequence current waveform data based on the sampling frequency without the standard sampling frequency to obtain the transient peak error comprises:
based on the condition that the maximum transient peak value error of the waveform under each sampling frequency and the waveform of the standard sampling frequency cannot be larger than a preset value, comparing and calculating transient zero-sequence current waveform data of each fault line under each sampling frequency under different transition resistors, different fault distances and different fault phase angles to obtain the maximum transient peak value instantaneous error;
and drawing a line graph about the sampling frequency and the maximum transient peak instantaneous error based on the maximum transient peak instantaneous errors under different transition resistances, different fault distances and different fault phase angles to obtain a transient peak error trend.
5. The method of claim 4, wherein the maximum transient peak instantaneous error is calculated as:
where ERROR is the maximum transient peak instantaneous ERROR, yitpIs a transient peak value y at a sampling frequency of i (kHz)10tpIs a transient peak value when the sampling frequency is the standard sampling frequency.
6. The method of claim 5, wherein said plotting a line graph for sampling frequency and maximum transient peak instantaneous error based on said maximum transient peak instantaneous error at different fault phase angles, different fault distances, and different transition resistances, resulting in a transient peak error trend, comprises:
and respectively changing the transition resistance, the fault distance and the fault phase angle, and sequentially increasing the sampling frequency to obtain a linear graph in which the instantaneous errors of the maximum transient peak value all show a descending trend along with the increase of the sampling frequency and the descending trend tends to be stable when the preset sampling frequency is reached.
7. The method of claim 1, wherein the line and component parameters comprise: power transmission line, power supply parameters, transformer parameters and load parameters;
the transmission line comprises: five-loop outgoing lines, two overhead lines, two cables and an overhead cable are mixed to be outgoing.
8. The method of claim 5, wherein the neutral-grounded arc suppression coil system simulation model utilizes MATLAB/Simulink software to simulate a typical power distribution network for a neutral-grounded arc suppression coil system for three-phase modeling.
9. The utility model provides a join in marriage net fault indicator recording accuracy test system which characterized in that includes: a waveform data module and an error solving module;
the waveform data module is used for inputting a plurality of simulation time step lengths and influence factors corresponding to the simulated single-phase earth fault of the power distribution network into a pre-constructed simulation model of the neutral point arc suppression coil grounding system to obtain transient zero-sequence current waveform data under different sampling frequencies;
the error solving module is used for comparing transient zero-sequence current waveform data under a preset standard sampling frequency with transient zero-sequence current waveform data under sampling frequencies which do not contain the standard sampling frequency in different frequencies to obtain a transient peak value error;
the simulation model of the neutral point arc suppression coil grounding system is constructed by three-phase modeling of a typical power distribution network simulated by the neutral point arc suppression coil grounding system and set circuit and element parameters.
10. The system of claim 9, wherein the waveform data module comprises: a transient zero-sequence current data submodule and a waveform submodule;
the transient zero-sequence current data submodule is used for simulating each fault type of single-phase grounding of the power distribution network based on values of influence factors, and obtaining transient zero-sequence current data with a plurality of sampling frequencies of preset data points in a sampling time period according to a plurality of simulation time step lengths corresponding to the single-phase grounding faults;
the waveform submodule is used for drawing the transient zero-sequence current waveform with multiple sampling frequencies based on the transient zero-sequence current data with multiple sampling frequencies of preset data points in the sampling time period.
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| CN115327298A (en) * | 2022-08-12 | 2022-11-11 | 国网福建省电力有限公司 | Detection waveform generation method and system for studying and judging single-phase earth fault |
| CN117113607A (en) * | 2023-10-23 | 2023-11-24 | 国网信息通信产业集团有限公司 | Small-current ground fault characteristic information extraction method, equipment and medium |
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| CN115327298A (en) * | 2022-08-12 | 2022-11-11 | 国网福建省电力有限公司 | Detection waveform generation method and system for studying and judging single-phase earth fault |
| CN117113607A (en) * | 2023-10-23 | 2023-11-24 | 国网信息通信产业集团有限公司 | Small-current ground fault characteristic information extraction method, equipment and medium |
| CN117113607B (en) * | 2023-10-23 | 2024-02-06 | 国网信息通信产业集团有限公司 | Small-current ground fault characteristic information extraction method, equipment and medium |
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