CN108828316B - Line parameter measuring method and device and electronic equipment - Google Patents
Line parameter measuring method and device and electronic equipment Download PDFInfo
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Abstract
The invention provides a line parameter measuring method, a device and electronic equipment, and relates to the technical field of line parameters, wherein the method comprises the steps of obtaining a line structure of a line to be measured, and an open triangular voltage and a three-phase current of a secondary side of a voltage transformer on a bus of the line to be measured; calculating a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured according to the open triangular voltage and the three-phase current; and measuring the line parameters of the line to be measured according to the line structure of the line to be measured, the sampling value of the zero sequence voltage to the ground and the sampling value of the zero sequence current to the ground. The invention can accurately measure the line parameters.
Description
Technical Field
The present invention relates to the technical field of line parameters, and in particular, to a line parameter measuring method, device and electronic device.
Background
In an electric power system, measurement of line parameters plays a key role in power grid load flow calculation, relay protection setting and power grid line loss measurement, so that the line parameters need to be accurately measured. In the traditional line parameter measurement method based on the injection signal, the frequency of the adopted injection signal is generally higher than the power frequency, high-frequency resonance is easily caused, and the accuracy of line parameter measurement is influenced.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a method, an apparatus and an electronic device for measuring line parameters, so as to measure line parameters more accurately.
In order to achieve the above purpose, the embodiment of the present invention adopts the following technical solutions:
in a first aspect, an embodiment of the present invention provides a line parameter measurement method, where the method includes: acquiring a line structure of a line to be measured, and an open triangular voltage and a three-phase current of a secondary side of a voltage transformer on a bus of the line to be measured; the neutral point of a capacitor bank on a bus of a line to be measured is injected with a current signal with a specific frequency; the specific frequency is lower than 50 Hz; the open delta voltage and the three-phase current are both related to a current signal with a specific frequency; calculating a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured according to the open triangular voltage and the three-phase current; measuring the line parameters of the line to be measured according to the line structure of the line to be measured, the sampling value of the zero sequence voltage to the ground and the sampling value of the zero sequence current to the ground; wherein the line parameters at least comprise line resistance and/or line-to-ground capacitance.
With reference to the first aspect, an embodiment of the present invention provides a first possible implementation manner of the first aspect, where the step of calculating a ground-zero sequence voltage sampling value and a ground-zero sequence current sampling value of the line to be measured according to the open-delta voltage and the three-phase current includes: determining that the sampling value of the ground zero sequence voltage of the line to be measured is equal to the open delta voltage value; and calculating the mean value of the three-phase current to obtain a sampling value of the ground zero sequence current of the line to be measured.
With reference to the first aspect, an embodiment of the present invention provides a second possible implementation manner of the first aspect, where the step of measuring a line parameter of the line to be measured according to a line structure of the line to be measured and the sampled values of the ground-zero sequence voltage and the ground-zero sequence current includes: acquiring an incidence relation between voltage and current corresponding to a line structure and line parameters; and calculating the line parameters of the line to be measured according to the correlation relationship, the sampling value of the zero sequence voltage to the ground and the sampling value of the zero sequence current to the ground.
With reference to the first aspect, an embodiment of the present invention provides a third possible implementation manner of the first aspect, where an association relationship between a voltage and a current corresponding to a line structure and a line parameter is expressed as:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
With reference to the first aspect, an embodiment of the present invention provides a fourth possible implementation manner of the first aspect, where an association relationship between a voltage and a current corresponding to a line structure and a line parameter is expressed as:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
In a second aspect, an embodiment of the present invention further provides a line parameter measuring apparatus, including: the acquisition module is used for acquiring a line structure of a line to be measured, and secondary side opening triangular voltage and three-phase current of a voltage transformer on a bus of the line to be measured; the neutral point of a capacitor bank on a bus of a line to be measured is injected with a current signal with a specific frequency; the specific frequency is lower than 50 Hz; the open triangle and the three-phase current are both related to a current signal with a specific frequency; the sampling value calculation module is used for calculating a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured according to the open triangular voltage and the three-phase current; the circuit parameter measuring module is used for measuring the circuit parameters of the circuit to be measured according to the circuit structure of the circuit to be measured, the sampling value of the zero sequence voltage to the ground and the sampling value of the zero sequence current to the ground; wherein the line parameters include at least line resistance and line-to-ground capacitance.
In a third aspect, an embodiment of the present invention provides an electronic device, including: a processor and a memory; the memory has stored thereon a computer program which, when executed by the processor, performs the method according to any one of the first to fourth possible implementation manners of the first aspect.
In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, performs the steps of the method in any one of the first to fourth possible implementation manners of the first aspect.
The embodiment of the invention provides a line parameter measuring method, a device and electronic equipment, wherein a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of a line to be measured are calculated through acquired open triangular voltage and three-phase current; and further measuring the line parameters of the line to be measured according to the obtained line structure of the line to be measured and the calculated sampling value of the ground zero sequence voltage and the sampling value of the ground zero sequence current of the line to be measured. The line parameter is measured based on the injection current signal with the specific frequency lower than 50Hz, and adverse effects such as resonance caused by high-frequency signals can be effectively reduced, so that the line parameter can be measured accurately.
Additional features and advantages of the disclosure will be set forth in the description which follows, or in part may be learned by the practice of the above-described techniques of the disclosure, or may be learned by practice of the disclosure.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart illustrating a method for measuring line parameters according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an injection signal provided by an embodiment of the present invention;
FIG. 3 is a flow chart of another line parameter measurement method provided by the embodiment of the invention;
FIG. 4 is a schematic diagram of an equivalent circuit model of a circuit structure provided by an embodiment of the invention;
fig. 5 is a block diagram illustrating a circuit parameter measuring apparatus according to an embodiment of the present invention;
fig. 6 shows a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In consideration of the fact that accurate parameters of a line need to be obtained in an electric power system, and the measurement precision of the line parameters is not high in the conventional line parameter measurement method, embodiments of the present invention provide a line parameter measurement method, a device and an electronic device, which can accurately measure line parameters, and the following detailed description of embodiments of the present invention is provided.
Referring to fig. 1, a flow chart of a line parameter measurement method, which may be performed by an electronic device such as a computer, a mobile phone, a line parameter measurement device, etc., includes the steps of:
step S102, acquiring a line structure of a line to be measured, and an open triangular voltage and a three-phase current of a secondary side of a voltage transformer on a bus of the line to be measured; the neutral point of a capacitor bank on a bus of a line to be measured is injected with a current signal with a specific frequency; the specific frequency is lower than 50 Hz; and the open delta voltage and the three-phase current are both related to a current signal of a specific frequency.
In a specific embodiment, the line structure of the line to be measured is pre-recorded into the electronic device by a user, and the secondary side opening triangular voltage and the three-phase current of the voltage transformer on the bus of the line to be measured can be obtained by the electronic device through the transformer. During practical application, the open triangular voltage can be obtained by measuring through a high-precision voltage transformer, the three-phase current of the line to be measured can be obtained by measuring through a high-precision current transformer, and the open triangular voltage and the three-phase current which are respectively collected by the voltage transformer and the current transformer are sent to the electronic equipment in a communication mode. In specific implementation, a current signal with a specific frequency lower than 50Hz can be injected into a neutral point of a capacitor bank on a bus of a line to be measured; fig. 2 shows a schematic diagram of an injection signal provided by an embodiment of the present invention, where fig. 2 includes a power supply, a load, a low-frequency current signal, and a 10kV bus, where Uo represents an open delta voltage on a secondary side of a voltage transformer on the bus, and Ia, Ib, and Ic represent three-phase currents. The frequency of the injected current signal is lower than 50Hz, such as 20Hz, the injected current signal is not too large, otherwise the normal operation of a line can be interfered, the injected current signal is not too small, otherwise the detection of the signal is not facilitated, in practice, 1-10A current is injected according to the precision of a mutual inductor, in order to ensure the measurement accuracy, at least 24 points are needed for each cycle wave when the injected signal is sampled, and the frequency of the sampled signal can be 500 Hz; the line structure of the line to be measured can be equivalent to a corresponding circuit model.
And step S104, calculating a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured according to the open triangular voltage and the three-phase current.
It can be understood that the sampling value of the zero sequence voltage to ground of the line to be measured is equal to the value of the open-delta voltage; an incidence relation exists between the ground zero sequence current sampling value and the three-phase current of the line to be measured, and specifically, the incidence relation can be an equality relation which is satisfied between the ground zero sequence current sampling value and the three-phase current of the line to be measured; and obtaining the ground zero sequence current sampling value of the line to be measured by the three-phase current according to the incidence relation.
Step S106, measuring the line parameters of the line to be measured according to the line structure of the line to be measured, the sampling value of the zero sequence voltage to the ground and the sampling value of the zero sequence current to the ground; wherein the line parameters at least comprise line resistance and/or line-to-ground capacitance.
In practical application, different circuit structures have respective corresponding relations of voltage, current and circuit parameters. Based on the method, the ground zero sequence voltage and the ground zero sequence current of the line to be measured can be substituted into the relational expression corresponding to the line structure, the line parameters of the line to be measured are obtained through calculation, and a more accurate line equivalent circuit is adopted, so that the calculation precision is higher.
The line parameter measuring method provided by the embodiment of the invention comprises the steps of obtaining a line structure of a line to be measured, and a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured; and then according to the line structure of the line to be measured and the sampling value of zero sequence voltage to ground and the sampling value of zero sequence current to ground, the line parameter of the line to be measured is measured, compared with the prior art that the frequency of the injected signal is higher and higher than 50Hz, high-frequency resonance is easily caused, and the accuracy of the measurement result is not high enough. The injection signal with the specific frequency provided by the embodiment has the specific frequency lower than 50Hz, and can accurately measure the line parameters.
The center of gravity of the traditional ground line parameter measurement method is mostly placed on the measurement of the line-to-ground capacitance, and the measurement of the line resistance is usually ignored. However, as the voltage level decreases, the ratio of the line resistance to the total impedance also increases, and theoretically calculated line parameters (pi concentration parameters) include: the ground of the line is distributed with capacitance, resistance and zero sequence inductance. The parameters of the calculation can be selected according to the needs in practical application. Generally speaking, the capacitance to ground reflects the magnitude of the capacitance current of the system after a single-phase earth fault occurs, which is an important parameter and needs to be calculated; the line resistance reflects the line loss in normal operation, is also an important parameter, and needs to be calculated. In contrast, the zero sequence inductance value can be calculated according to the need, and if the calculation is needed, the number of unknowns of the equation and the order of the differential equation are increased. The method thus chooses to calculate the capacitance and resistance.
For ease of understanding, a specific implementation of the line parameter measurement method provided based on the present embodiment is given below, referring to a flowchart of another line parameter measurement method shown in fig. 3, where the method includes the following steps:
step S302, acquiring a line structure of a line to be measured, and an open triangular voltage and a three-phase current of a secondary side of a voltage transformer on a bus of the line to be measured; the neutral point of a capacitor bank on a bus of a line to be measured is injected with a current signal with a specific frequency; the specific frequency is lower than 50 Hz; and the open delta voltage and the three-phase current are both related to a current signal of a specific frequency.
In specific implementation, the line parameters can be measured in the obtained circuit model equivalent to the line structure of the line to be measured; in order to ensure the measurement accuracy, at least 24 points are needed per cycle when the injection signal is sampled, the frequency of the sampling signal can be 500Hz, the sampling frequency can be continuously increased if higher measurement accuracy is needed in practice, but the time and data volume for measuring the line parameters are greatly increased; therefore, 500Hz is the choice which can meet the engineering requirements after comprehensively considering the calculation speed and the measurement precision.
Step S304, determining that the sampling value of the zero sequence voltage to ground of the line to be measured is equal to the open delta voltage value.
In a specific embodiment, the sampling value of the zero sequence voltage to ground of the line to be measured is equal to the value of the open delta voltage on the secondary side of the voltage transformer on the bus.
And S306, calculating the mean value of the three-phase current to obtain a ground zero sequence current sampling value of the line to be measured.
In a specific embodiment, the sampling value of the ground zero sequence current of the line to be measured is equal to the mean value of the three-phase currents, so that the sampling value of the ground zero sequence current of the line to be measured can be obtained by calculating the mean value of the three-phase currents.
Step S308, acquiring the association relation between the voltage and the current corresponding to the line structure and the line parameters. The correlation between the voltage and the current corresponding to the circuit structure provided by this embodiment and the circuit parameter is expressed as follows:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
The above-mentioned correlation is a time-domain differential equation in a circuit model of a circuit structure equivalent, fig. 4 shows a schematic diagram of an equivalent circuit model of a circuit structure provided in an embodiment of the present invention, u and i in fig. 4 respectively represent a sampling value of a ground zero-sequence voltage and a sampling value of a ground zero-sequence current of a line to be measured, and R and C respectively represent a line resistance and a line capacitance to ground. In order to further improve the accuracy of parameter calculation, through the research of the inventor, the two ends of the formula can be integrated for the first time, and the numerical error caused by the second order differential is reduced through integration, so that the time domain differential equation can be transformed into the following time domain differential integral equation:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
And step S310, calculating the line parameters of the line to be measured according to the incidence relation, the sampling value of the zero sequence voltage to the ground and the sampling value of the zero sequence current to the ground.
Specifically, R, C unknowns exist in a time domain calculus equation represented by the incidence relation, a ground zero sequence voltage sampling value and a ground zero sequence current sampling value are obtained at different sampling moments, and can be used as u and i substitution equations in the formula to solve R and C in a simultaneous mode. Although the unknown number is two, namely theoretically, at least two groups of time domain calculus equations can be solved by simultaneous establishment, if the coefficient on the left side of the time domain calculus equation is shifted to the right side, the highest order of the unknown quantity C is two, so that only the value simultaneous equations at two sampling moments are taken, two solutions can be obtained, manual further identification is needed to determine the unique solution, and the possibility of error exists.
In summary, by using the line parameter measurement method provided in this embodiment, the line parameters are measured by using a time domain calculus equation represented by an association relationship between voltage and current corresponding to the line structure and the line parameters; the time domain method, namely the calculus equation is adopted for calculation, so that the method is insensitive to signal frequency change and does not need to additionally install a filtering device; in addition, in practice, the sampling frequency can be increased according to requirements so as to improve the calculation precision, and the line parameters can be measured more accurately.
In the prior art, most methods for measuring line parameters adopt a phasor method to calculate the parameters, however, the phasor equation must be calculated under the same frequency, so that the calculation process is complicated, the filtering requirement is high, and the accuracy of line parameter measurement is influenced. The invention adopts a time domain method, namely a calculus equation, to measure the line parameters, is insensitive to the change of signal frequency, does not need to additionally install a filter device, and has more accurate measurement result.
The line parameter measurement method provided by the embodiment can be called a low-frequency signal injection-based line parameter measurement method, the method provides a calculus equation processing signal, a low-frequency signal of 20Hz is injected into a system through a neutral point of a capacitor bank by using a current source, and accurate line parameters are obtained by utilizing zero sequence voltage and current sampling values measured on a bus through calculus calculation.
For the convenience of understanding, a specific implementation manner of the line parameter measurement method based on low-frequency signal injection is given as follows:
(1) and injecting a current signal with the constant frequency of 20Hz from the neutral point of the capacitor bank connected in parallel on the bus. The injected current signal is not too large, otherwise the normal operation of the line can be interfered, or not too small, otherwise the signal detection is not facilitated, and practically, 1-10A current is injected according to the precision of the mutual inductor.
(2) In order to ensure the accuracy of line parameter measurement, the injection signal should be sampled at least 24 points per cycle, and the sampling signal frequency can be 500 Hz. During simulation test, the actual value of the resistor R is 7.1 omega, the measured value is 7.027 omega, and the relative error is about 1%; the actual value of the capacitor C is 8.409995 multiplied by 10-8F, measured at 8.410385X 10-8F, the relative error is less than 1 per thousand. In practice the sampling frequency can be increased further if higher measurement accuracy is required. For example, when other parameters are unchanged and the sampling frequency is only increased to 1000Hz, the measured value of the resistance R is 7.067 Ω, the relative error is 5% o, and the measured value of the capacitance C is 8.409322 × 10-8F, the relative error is less than one ten thousandth. But the time and data volume used for calculation are greatly increased, so that the 500Hz is a choice which can meet the engineering requirements after the calculation speed and the measurement precision are comprehensively considered.
(3) Obtaining open triangular voltage Uo and three-phase current I of secondary side of voltage transformer on bus by using high-precision current-voltage transformera、Ib、Ic。
(4) The ground zero sequence voltage U is obtained by the following formula0And current sampling value I0：
U0＝Uo
I0＝(Ia+Ib+Ic)/3
(5) Listing time-domain differential equations from a circuit model
Wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
(6) Considering that the integral can further reduce the numerical error brought by the second order differential, the integral is performed once at two ends of the formula (5), and the time domain calculus equation is transformed as follows:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
(7) At three different sampling times t1, t2 and t3, U is equal to U0，i＝I0Substituting the above equation, the simultaneous equation solves R, C. Although the number of unknowns is R, C, theoretically, at least two sets of time domain calculus equations can be simultaneously solved. However, if the left coefficient of the equation (6) is shifted to the right, it can be seen that the highest order of the unknown quantity C is the second order, and therefore, only the simultaneous equations of the values at two sampling moments are taken, two solutions will be obtained, further manual identification is needed to determine the unique solution, and there is a possibility of error, so that a set of equations is added to directly obtain the unique and accurate solution.
In specific implementation, a single frequency signal is injected, the steps are simple, the practical application is convenient, and high-frequency resonance is not easy to occur; the line parameter measurement is carried out by adopting a time domain method, namely a calculus equation, so that the line parameter measurement is insensitive to signal frequency change, a filtering device is not required to be additionally arranged, and the sampling frequency can be increased according to requirements so as to improve the measurement precision and enable the parameter measurement to be more accurate.
Corresponding to the foregoing line parameter measuring method, an embodiment of the present invention provides a line parameter measuring device, referring to a structural block diagram of the line parameter measuring device shown in fig. 5, where the device includes the following modules:
an obtaining module 502, configured to obtain a line structure of a line to be measured, and an open delta voltage and a three-phase current of a secondary side of a voltage transformer on a bus of the line to be measured; the neutral point of a capacitor bank on a bus of a line to be measured is injected with a current signal with a specific frequency; the specific frequency is lower than 50 Hz; the three-phase voltage and the three-phase current are related to a current signal with a specific frequency;
the sampling value calculation module 504 is configured to calculate a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured according to the open delta voltage and the three-phase current;
the line parameter measuring module 506 is used for measuring line parameters of the line to be measured according to the line structure of the line to be measured, the sampling value of the zero-sequence voltage to ground and the sampling value of the zero-sequence current to ground; wherein the line parameters include at least line resistance and line-to-ground capacitance.
According to the line parameter measuring device provided by the embodiment of the invention, the sampling value of the ground zero sequence voltage and the sampling value of the ground zero sequence current of the line to be measured are calculated through the acquired open delta voltage and the three-phase current; and further measuring the line parameters of the line to be measured according to the obtained line structure of the line to be measured and the calculated sampling value of the ground zero sequence voltage and the sampling value of the ground zero sequence current of the line to be measured. The embodiment adopts the injection signal with the specific frequency, and the specific frequency is lower than 50Hz, so that the line parameters can be measured more accurately.
The line parameter measurement module 506 is further configured to: acquiring an incidence relation between voltage and current corresponding to a line structure and line parameters; and calculating the line parameters of the line to be measured according to the correlation relationship, the sampling value of the zero sequence voltage to the ground and the sampling value of the zero sequence current to the ground. The incidence relation of the voltage and the current corresponding to the line structure and the line parameters is expressed as follows:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
The device provided by the embodiment has the same implementation principle and technical effect as the foregoing embodiment, and for the sake of brief description, reference may be made to the corresponding contents in the foregoing method embodiment for the portion of the embodiment of the device that is not mentioned.
An embodiment of the present invention provides an electronic device, referring to a schematic structural diagram of an electronic device shown in fig. 6, where the electronic device includes: a processor 60, a memory 61, a bus 62 and a communication interface 63, wherein the processor 60, the communication interface 63 and the memory 61 are connected through the bus 62; the processor 60 is arranged to execute executable modules, such as computer programs, stored in the memory 61.
The Memory 61 may include a high-speed Random Access Memory (RAM) and may also include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory. The communication connection between the network element of the system and at least one other network element is realized through at least one communication interface 63 (which may be wired or wireless), and the internet, a wide area network, a local network, a metropolitan area network, and the like can be used.
The bus 62 may be an ISA bus, PCI bus, EISA bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one double-headed arrow is shown in FIG. 6, but that does not indicate only one bus or one type of bus.
The memory 61 is used for storing a program, the processor 60 executes the program after receiving an execution instruction, and the method executed by the apparatus defined by the flow process disclosed in any of the foregoing embodiments of the present invention may be applied to the processor 60, or implemented by the processor 60.
The processor 60 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 60. The Processor 60 may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like; the device can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components. The various methods, steps and logic blocks disclosed in the embodiments of the present invention may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in a memory 61, and the processor 60 reads the information in the memory 61 and, in combination with its hardware, performs the steps of the above method.
Embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, performs the steps of the method of any one of the foregoing embodiments.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process of the system described above may refer to the corresponding process in the foregoing embodiments, and is not described herein again.
The line parameter measurement method, the line parameter measurement device and the computer program product of the electronic device provided by the embodiments of the present invention include a computer readable storage medium storing a program code, where instructions included in the program code may be used to execute the method described in the foregoing method embodiments, and specific implementation may refer to the method embodiments, and will not be described herein again.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (5)
1. A method for measuring a line parameter, comprising:
acquiring a line structure of a line to be measured, and an open triangular voltage and a three-phase current of a secondary side of a voltage transformer on a bus of the line to be measured; a neutral point of a capacitor bank on a bus of the line to be measured is injected with a current signal with a specific frequency; the specific frequency is lower than 50 Hz; the open delta voltage and the three-phase current are both related to the current signal with the specific frequency;
calculating a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured according to the open triangular voltage and the three-phase current;
measuring the line parameters of the line to be measured according to the line structure of the line to be measured, the ground zero sequence voltage sampling value and the ground zero sequence current sampling value; wherein the line parameters at least comprise line resistance and line-to-ground capacitance;
the step of calculating the sampling value of the ground zero sequence voltage and the sampling value of the ground zero sequence current of the line to be measured according to the open delta voltage and the three-phase current comprises the following steps:
determining that the sampling value of the ground zero sequence voltage of the line to be measured is equal to the open delta voltage value;
calculating the mean value of the three-phase current to obtain a ground zero sequence current sampling value of the line to be measured;
the step of measuring the line parameters of the line to be measured according to the line structure of the line to be measured, the sampling value of the ground zero sequence voltage and the sampling value of the ground zero sequence current comprises the following steps:
acquiring the incidence relation between the voltage and the current corresponding to the line structure and the line parameters;
calculating the line parameters of the line to be measured according to the incidence relation, the ground zero sequence voltage sampling value and the ground zero sequence current sampling value;
the incidence relation of the voltage and the current corresponding to the line structure and the line parameters is expressed as follows:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
2. The method of claim 1, wherein the correlation between the voltage and the current corresponding to the circuit structure and the circuit parameter is represented as:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
3. A line parameter measuring device, comprising:
the acquisition module is used for acquiring a line structure of a line to be measured, and an open triangle and three-phase current of a secondary side of a voltage transformer on a bus of the line to be measured; a neutral point of a capacitor bank on a bus of the line to be measured is injected with a current signal with a specific frequency; the specific frequency is lower than 50 Hz; the open delta voltage and the three-phase current are both related to the current signal with the specific frequency;
the sampling value calculation module is used for calculating a ground zero sequence voltage sampling value and a ground zero sequence current sampling value of the line to be measured according to the open triangular voltage and the three-phase current;
the line parameter measuring module is used for measuring the line parameters of the line to be measured according to the line structure of the line to be measured, the ground zero sequence voltage sampling value and the ground zero sequence current sampling value; wherein the line parameters at least comprise line resistance and line-to-ground capacitance;
wherein the sampling value calculation module is further configured to:
determining that the sampling value of the ground zero sequence voltage of the line to be measured is equal to the open delta voltage value;
calculating the mean value of the three-phase current to obtain a ground zero sequence current sampling value of the line to be measured;
the line parameter measurement module is further configured to:
acquiring the incidence relation between the voltage and the current corresponding to the line structure and the line parameters;
calculating the line parameters of the line to be measured according to the incidence relation, the ground zero sequence voltage sampling value and the ground zero sequence current sampling value;
the incidence relation of the voltage and the current corresponding to the line structure and the line parameters is expressed as follows:
wherein C represents the capacitance of the line to ground, R represents the resistance of the line, u represents the instantaneous value of the line voltage, and i represents the instantaneous value of the line current.
4. An electronic device comprising a processor and a memory;
the memory has stored thereon a computer program which, when executed by the processor, performs the method of any of claims 1 to 2.
5. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of the preceding claims 1 to 2.
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