CN115438299B - Real-time calculation method and system for transformer area line impedance, electronic equipment and storage medium - Google Patents
Real-time calculation method and system for transformer area line impedance, electronic equipment and storage medium Download PDFInfo
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Abstract
The invention discloses a method and a system for calculating the line impedance of a transformer area in real time, electronic equipment and a storage medium. By constructing a loop impedance equation set of a topological area and establishing a target planning problem to solve a line impedance value, real-time calculation of any line impedance value of a transformer area can be realized, the influence of other line loads on an impedance calculation line is considered, the accuracy of line impedance calculation is greatly improved, the accuracy of tide calculation, electricity stealing detection or transformer area line loss analysis calculation is improved, abnormal transformer area lines can be found in time, and accurate positioning is realized.
Description
Technical Field
The present invention relates to the field of line impedance computing technologies, and in particular, to a method and system for real-time computing of line impedance of a transformer area, an electronic device, and a computer readable storage medium.
Background
Along with the development of the power industry and the increase of power demand, the digitalization and intelligence degree of the power grid are also higher and higher, and various electric quantity data are gradually perfected. However, the line impedance value of the transformer area is generally referred to the line impedance parameter marked on the drawing when the distribution network is designed and planned, and when the line is aged, leaked or stolen, if the initial impedance parameter is adopted to perform load flow calculation, power stealing detection or line loss analysis calculation of the transformer area, the actual line loss electric energy is much higher than the calculated line loss, so that the calculation of the actual line impedance of the transformer area is necessary. Patent CN202010053775.0 previously filed by the inventor discloses a method for calculating a power supply line impedance value based on load jump, which is to obtain voltage measurement values and current measurement values of two branch units before and after the load jump, and calculate a line impedance value between the two branch units based on a measured value difference value, so as to eliminate the influence of errors of an ammeter and influence errors on a calculation result. However, the method needs to calculate the impedance based on the electric quantity data before and after the occurrence of the load jump, so that the real-time calculation of the impedance of the line of the transformer area cannot be realized, and the method does not consider the influence of the load of other lines on the line when calculating the impedance of one line, so that the calculated impedance value is larger in vertical floating and is not consistent with the actual value.
Disclosure of Invention
The invention provides a real-time calculation method and system for the impedance of a line in a transformer area, electronic equipment and a computer-readable storage medium, which are used for solving the technical problems that the existing impedance calculation method cannot realize the real-time calculation of the impedance of the line in the transformer area and the accuracy of a calculation result is poor because the influence of other line loads is not considered.
According to one aspect of the present invention, there is provided a real-time calculation method for a line impedance of a transformer area, including:
Selecting a topological area needing impedance calculation, finding out head and tail nodes in the topological area, and acquiring freezing data of the head node and all tail nodes;
Constructing a loop impedance equation set of the topological area;
And establishing a target planning problem and solving the target planning problem based on the acquired frozen data to obtain a line impedance value between each end node and the head node in the topological area.
Further, the frozen data is hour frozen data, 15 minute frozen data, or minute frozen data.
Further, the phase-based split construction is performed when constructing the loop impedance equation set of the topology region.
Further, the constructed loop impedance equation set is:
Where V s represents the voltage data of the head node, U n represents the voltage data of the n-th end node, I n represents the current data of the n-th end node, Z n represents the line impedance value between the n-th end node and the head node, and Z pn represents the common branch impedance value between the p-th end node and the n-th end node to the head node.
Further, the step of establishing a target planning problem and solving the target planning problem based on the obtained frozen data to obtain the impedance value of the line between each end node and the head node in the topological area specifically comprises the following steps:
For each equation in the loop impedance equation set, establishing a target planning problem based on frozen data of the corresponding node at two moments:
Wherein, the superscript ta represents the frozen data at the time ta, the superscript tb represents the frozen data at the time tb, Z pi represents the impedance value of the common branch from the p-th end node and the i-th end node to the head node, and DeltaU represents the voltage difference between the head node and the p-th end node obtained by optimization solution at the time ta;
Solving the planning problem to obtain an optimal extremum solution delta U, if Epsilon is a preset precision threshold, which means that the solution value reaches the precision requirement, and the value of the P-th unknown quantity corresponding to the optimal solution is found, namely, the line impedance value Z p between the first node and the P-th end node;
and repeating the process, and solving to obtain the line impedance value from the head node to each end node.
Further, when solving the target planning problem, frozen data at the moment when the large current appears at the end node is selected for solving.
Further, the method also comprises the following steps:
Calculating to obtain a plurality of line impedance values between each end node and the head node in the topological area, setting a value interval according to the numerical conditions of the line impedance values, equally dividing the value interval into a plurality of subintervals, screening the subinterval with the largest line impedance value, calculating to obtain the line impedance value average value of the subinterval, and taking the line impedance value average value as the final line impedance value between the end node and the head node.
In addition, the invention also provides a real-time computing system for the line impedance of the transformer area, which comprises the following components:
the area selection module is used for selecting a topological area needing impedance calculation, finding out head and tail nodes in the topological area, and acquiring frozen data of the head node and all the tail nodes;
The equation set construction module is used for constructing a loop impedance equation set of the topological area;
and the calculation module is used for establishing a target planning problem and solving the target planning problem based on the acquired frozen data to obtain a line impedance value between each end node and the head node in the topological area.
In addition, the invention also provides an electronic device comprising a processor and a memory, wherein the memory stores a computer program, and the processor is used for executing the steps of the method by calling the computer program stored in the memory.
In addition, the present invention also provides a computer readable storage medium storing a computer program for performing real-time calculation of the line impedance of a station area, said computer program executing the steps of the method as described above when running on a computer.
The invention has the following effects:
According to the method for calculating the line impedance of the transformer area in real time, a topological area needing impedance calculation is selected, the first node and the last node of the topological area are found, freezing data of the first node and all the end nodes are obtained, a loop impedance equation set of the topological area is built, then a target planning problem is established, and the solution is carried out based on the obtained freezing data, so that the line impedance value from each end node to the first node in the topological area is obtained. According to the real-time calculation method for the line impedance of the transformer area, the loop impedance equation set of the topological area is constructed, the target planning problem is established to solve the line impedance value, the line impedance value is calculated based on the frozen data at any moment, the real-time calculation of any line impedance value of the transformer area can be realized, in the constructed loop impedance equation set, the influence of other line loads on the impedance calculation line is considered, the accuracy of line impedance calculation is greatly improved, the accuracy of tide calculation, electricity stealing detection or analysis calculation of the line loss of the transformer area is improved, the abnormal line of the transformer area is found in time, and the accurate positioning is realized.
In addition, the real-time calculation system for the line impedance of the transformer area has the advantages.
In addition to the objects, features and advantages described above, the present invention has other objects, features and advantages. The present invention will be described in further detail with reference to the drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
fig. 1 is a flow chart of a method for calculating the line impedance of a transformer area in real time according to a preferred embodiment of the present invention.
Fig. 2 is a schematic diagram of a cell line topology.
Fig. 3 is a schematic diagram of a circuit topology with only one end node in the topology region in a preferred embodiment of the invention.
Fig. 4 is a schematic diagram of a circuit topology having two end nodes in a topology region in accordance with a preferred embodiment of the present invention.
Fig. 5 is a flowchart of a method for calculating the line impedance of a transformer area in real time according to another embodiment of the present invention.
Fig. 6 is a schematic block diagram of a real-time computing system for the impedance of a line in a transformer area according to another embodiment of the present invention.
Detailed Description
Embodiments of the invention are described in detail below with reference to the attached drawing figures, but the invention can be practiced in a number of different ways, as defined and covered below.
As shown in fig. 1, a preferred embodiment of the present invention provides a method for calculating a line impedance of a transformer area in real time, which includes the following steps:
step S1: selecting a topological area needing impedance calculation, finding out head and tail nodes in the topological area, and acquiring freezing data of the head node and all tail nodes;
step S2: constructing a loop impedance equation set of the topological area;
step S3: and establishing a target planning problem and solving the target planning problem based on the acquired frozen data to obtain a line impedance value between each end node and the head node in the topological area.
It can be understood that in the method for calculating the line impedance of the transformer area in real time, firstly, a topological area needing to be subjected to impedance calculation is selected, the first node and the last node of the topological area are found, freezing data of the first node and all the end nodes are obtained, a loop impedance equation set of the topological area is built, then a target planning problem is established, and the solution is carried out based on the obtained freezing data, so that a line impedance value from each end node to the first node in the topological area is obtained. According to the real-time calculation method for the line impedance of the transformer area, the loop impedance equation set of the topological area is constructed, the target planning problem is established to solve the line impedance value, the line impedance value is calculated based on the frozen data at any moment, the real-time calculation of any line impedance value of the transformer area can be realized, in the constructed loop impedance equation set, the influence of other line loads on the impedance calculation line is considered, the accuracy of line impedance calculation is greatly improved, the accuracy of tide calculation, electricity stealing detection or analysis calculation of the line loss of the transformer area is improved, the abnormal line of the transformer area is found in time, and the accurate positioning is realized.
It will be appreciated that the cell line impedance calculation needs to be based on a known cell line topology, i.e. a cell having a complete or partial complete topology of the total-branch-box terminal-subscriber table, as shown in fig. 2. In the step S1, the user may select a topology area for performing impedance calculation according to needs, which may be a complete topology area of the total table-user table or a partial topology area of the branch table-user table. Then, the head and tail nodes in the selected topological area are found according to the topological structure of the station area line, wherein the topological area generally comprises one head node and a plurality of tail nodes. Alternatively, the head node typically selects a summary table or primary branching unit, while the end node typically selects a table box terminal or subscriber table. And then, acquiring freezing data of the first node and all the last nodes, wherein the freezing data is in the form of hour freezing data, 15-minute freezing data or minute freezing data, and the freezing data comprises voltage data and current data. The hour freezing data refer to 24-point freezing data in one day, the 15-minute freezing data refer to 96-point freezing data in one day, and the minute freezing data refer to 60-point second freezing data in one minute. The user can select the type of freezing data according to needs, for example, when the freezing data in hour or 15 minutes are selected, daily impedance calculation can be performed so as to perform line loss calculation with larger time dimension and analyze the aging condition of the line of the station area, and when the freezing data in minute is selected, real-time impedance calculation can be performed so as to be beneficial to timely finding out the abnormality of the line of the station area and accurately positioning, and labor and material resources consumed by manually checking the line are saved.
It can be understood that in the step S2, the loop impedance equation set is constructed as follows:
Where V s represents the voltage data of the head node, U n represents the voltage data of the n-th end node, I n represents the current data of the n-th end node, Z n represents the line impedance value between the n-th end node and the head node, and Z pn represents the common branch impedance value between the p-th end node and the n-th end node to the head node.
It will be appreciated that the phase-based separate construction should be performed in constructing the loop impedance equations of the topological region. For example, when the end node of the topology area is a table box terminal, A, B, C three phases of the head node are required to be calculated in one-to-one correspondence with A, B, C three phases of the table box terminal, and when the end node of the topology area is a household table, the head node is divided into A, B, C three phases, and then calculation is performed according to all the household tables under each phase.
Next, taking the topological area of the total table to household table, the a phase as an example, the calculation is performed by periodically freezing the voltage U and the current I.
When the topology area has only a single end node, as shown in fig. 3, there is only one loop in the topology area, and it is known based on kirchhoff's voltage law that:
Vs＝Z11I1
Wherein V s represents the total voltage, I 1 represents the current of the household table 1, and Z 11 represents the sum of the line impedance from the total to the household table 1 and the load impedance of the household table 1.
When there are two end nodes in the topology area, as shown in fig. 4, three lines exist in the topology area, which are respectively: the line from the middle node to the home table 1, the line from the middle node to the home table 2, and the line from the middle node to the total table (i.e., the common leg of the home table 1 and the home table 2 to the total table). From kirchhoff's voltage law, the sum of the voltage drops on the line and the elements on each loop from table 1 to table 2 is equal to the sum of the total electromotive force algebraic, and the loop equations from table 1 to table 2 can be listed:
Wherein I Co-production ＝I1+I2 represents the current of the common branch, Z 12 represents the impedance of the common branch, Z In (a) 1 represents the sum of the line impedance value from the node to the subscriber table 1 and the load impedance value of the subscriber table 1, and Z In (a) 2 represents the sum of the line impedance value from the node to the subscriber table 2 and the load impedance value of the subscriber table 2.
Substituting I Co-production ＝I1+I2 into the above equation set yields:
recombination gives:
Let Z 11＝(Z12+Z In (a) 1)、Z22＝(Z12+Z In (a) 2),Z11 denote the sum of the line impedance of the table 1 to the total table and the load impedance of the table 1, and Z 22 denote the sum of the line impedance of the table 2 to the total table and the load impedance of the table 2, also referred to as the self-impedance. Thereby obtaining the following steps:
When the topological area has n user tables, the method can be obtained based on kirchhoff voltage law:
Wherein Z ii represents the self-impedance of the ith household table, Z ij (i.noteq.j) is the transimpedance, and represents the impedance of the common branch from the ith household table and the jth household table to the total table.
Then, the self-impedance Z ii is split into: z ii＝Zl+Zi, wherein Z l represents the load impedance of the ith household meter and Z i represents the line impedance from the ith household meter to the total table. And adding node current to obtain: z iiIi＝ZlIi+ZiIi, thereby obtaining: z iiIi＝Ui+ZiIi. Substituting it into the above equation set table and moving U i to the left gives a loop impedance equation set for the topological area:
Wherein V s represents the voltage data of the total table, U n represents the voltage data of the nth household table, I n represents the current data of the nth household table, Z n represents the line impedance value between the nth household table and the total table, and Z pn represents the common branch impedance value between the nth household table and the total table. Wherein Z n is the quantity to be solved.
It will be appreciated that the first node may also select a primary branching unit or a secondary branching unit, and the end node may also select a subscriber table terminal, and the construction process is consistent with the above process.
It may be appreciated that in the step S3, the step of establishing a target planning problem and solving based on the obtained frozen data to obtain the impedance value of the line between each end node and the head node in the topology area specifically includes:
For each equation in the loop impedance equation set, establishing a target planning problem based on frozen data of the corresponding node at two moments:
Wherein, the superscript ta represents the frozen data at the time ta, the superscript tb represents the frozen data at the time tb, Z pi represents the impedance value of the common branch from the p-th end node and the i-th end node to the head node, and DeltaU represents the voltage difference between the head node and the p-th end node obtained by optimization solution at the time ta;
Solving the planning problem to obtain an optimal extremum solution delta U, if Epsilon is a preset precision threshold, which means that the solution value reaches the precision requirement, and the value of the P-th unknown quantity corresponding to the optimal solution is found, namely, the line impedance value Z p between the first node and the P-th end node;
and repeating the process, and solving to obtain the line impedance value from the head node to each end node.
Specifically, taking an equation related to the end node p in the loop impedance equation set constructed in the step S2 as an example, n impedance values in the equation Vs-Up＝Zp1I1+Zp2I2+...+ZpIp+...+ZpnIn are solved. For equations with a plurality of unknowns, the conventional mode is to establish a multi-element linear equation set for solving by a plurality of groups of data at different moments, so that the calculated amount is extremely large, the efficiency is low and the solving effect is poor. Therefore, the invention solves the problem by establishing the objective planning problem and setting the objective function and the constraint condition. Firstly, determining a target function of a planning problem, requiring moment data, and establishing a series of constraint conditions according to the characteristic that the impedance is larger than 0 and the line impedance from a head node to a tail node p is larger than or equal to the transimpedance between the nodes, wherein the optimal solution obtained by solving the target planning problem has certain contingency. In analogy to the solution of a linear equation set, a single equation solution system is huge, increasing the number of equations reduces the range of the solution, and finally, a unique solution is obtained when the number of equations is equal to the number of unknowns. Therefore, more than one time of data is needed to participate in the target planning problem, so that the data of other times are added to the constraint condition, and when two or more time of equations are added to the constraint condition (when three or more time of data are used in total), the planning problem is not solved because of excessive constraint conditions, therefore, the invention preferably adopts the equation of only one time to the constraint condition, and the situation that the solution range is reduced accidentally and the solution range is not always not solved at the same time is avoided.
For example, the data at two times (time ta and time tb) are chosen to construct an equation, specifically:
the superscript ta indicates data at time ta, and the superscript tb indicates data at time tb.
Since the end node current, I 1～In, has the following relationship with the head node I s:
I1,I2,...,In≤Is
The impedance of the end node p at the times ta, tb is:
Taking the equation at the time ta as an objective function and taking the equation at the time tb as a first constraint condition of the objective function, namely:
And then according to the line impedance characteristic, the line impedance from the head node to a certain end node is necessarily greater than or equal to the common branch impedance of the end node and other end nodes to the head node, and then n-1 constraint conditions are as follows:
Zp-Zpi≥0,i＝1,2,...,n,i≠p
further, from the impedance characteristics, it is known that: z p,Zpi is not less than 0, i=1, 2.
In summary, a complete target planning problem can be established:
Solving the planning problem to obtain an optimal extremum solution delta U, if Then the solution value meets the precision requirement, and then the value of the p-th unknown quantity corresponding to the optimal solution is found out, namely the line impedance value Z p from the end node p to the head node.
And repeating the target planning solution for other end nodes to obtain the line impedance values between all the end nodes and the head node.
Optionally, when solving the objective planning problem, selecting frozen data at the moment when the end node generates a large current to solve. Because, according to ohm's law, the larger the current in the line, the larger the voltage drop on the line, typically, the wire impedance is in the mΩ level, the current of 1A can only produce a voltage drop of 1mV under the impedance action of 1mΩ, and the magnitude of the freezing voltage of the total table, the household table, and each terminal device therebetween is typically 0.1V or 0.01V, i.e. the minimum voltage drop can only reach 0.01V. If the selected line current is too small, the voltage drop is extremely low, and based on the limitation of voltage precision, the voltage drop caused by the line impedance cannot be reflected in the frozen data, so that when solving the target planning problem, the frozen data at the moment when the large current occurs at the end node is preferably selected, and the accuracy of the calculation result is further ensured.
Optionally, as shown in fig. 5, in another embodiment of the present invention, the method for calculating the impedance of the line of the station area in real time further includes the following:
Step S4: calculating to obtain a plurality of line impedance values between each end node and the head node in the topological area, setting a value interval according to the numerical conditions of the line impedance values, equally dividing the value interval into a plurality of subintervals, screening the subinterval with the largest line impedance value, calculating to obtain the line impedance value average value of the subinterval, and taking the line impedance value average value as the final line impedance value between the end node and the head node.
For example, 15 minutes of freezing data of 96 points a day is selected, and a time point sequence t 1,t2,...,tL satisfying the voltage and current conditions is searched from the freezing data every day for L (L.ltoreq.96) time points in total. Let ta=t i,tb＝tj, (i+.j) traverse all time points respectively, and calculate several line impedance values from each end node to the head node according to step S3, requiring that the line impedance value obtained by each end node is not less than η. Then, selecting a proper value interval [ A, B ] according to the line impedance value obtained by each end node, dividing the value interval [ A, B ] into a psi section, namely dividing the psi section into a psi subinterval, and taking the average value of the impedance value of the subinterval with the largest falling value as the line impedance value from the end node to the head node. The values of η and ψ may be set as desired.
Or selecting second-level freezing data of 60 points in one minute, and searching a time point sequence t 1,t2,...,tl meeting the voltage and current conditions from the data in each minute, wherein l (l is less than or equal to 96) time points in total. Let ta=t i,tb＝tj, (i+.j) traverse all time points respectively, and calculate several line impedance values from each end node to the head node according to step S3, requiring that each end node obtain line impedance values not less than γ. Then, selecting a proper value interval [ a, b ] according to the line impedance value obtained by each end node, dividing the value interval [ a, b ] into delta segments, namely delta subintervals, and taking the average value of the impedance value of the subinterval with the largest falling value as the line impedance value from the end node to the head node. The values of γ and δ can be set as necessary.
It can be understood that by dividing the intervals of the plurality of impedance values obtained for each end node, selecting the subinterval with the largest number of line impedance values, and taking the average value of the line impedance values in the subinterval as the final line impedance value between the end node and the head node, the influence of accidental errors can be reduced, and the accuracy of calculating the line impedance of the transformer area is further improved.
In addition, as shown in fig. 6, another embodiment of the present invention further provides a real-time computing system for the impedance of a line of a station, preferably adopting the method as described above, including:
the area selection module is used for selecting a topological area needing impedance calculation, finding out head and tail nodes in the topological area, and acquiring frozen data of the head node and all the tail nodes;
The equation set construction module is used for constructing a loop impedance equation set of the topological area;
and the calculation module is used for establishing a target planning problem and solving the target planning problem based on the acquired frozen data to obtain a line impedance value between each end node and the head node in the topological area.
It can be understood that in the real-time computing system for the line impedance of the transformer area of the embodiment, firstly, a topological area needing to be subjected to impedance computation is selected, the first node and the last node of the topological area are found, freezing data of the first node and all the end nodes are obtained, a loop impedance equation set of the topological area is built, then a target planning problem is established, and the solution is carried out based on the obtained freezing data, so that the line impedance value from each end node to the first node in the topological area is obtained. According to the real-time calculation system for the line impedance of the transformer area, the loop impedance equation set of the topological area is constructed, the target planning problem is established to solve the line impedance value, the line impedance value is calculated based on the frozen data at any moment, the real-time calculation of any line impedance value of the transformer area can be realized, in the constructed loop impedance equation set, the influence of other line loads on the impedance calculation line is considered, the accuracy of line impedance calculation is greatly improved, the accuracy of tide calculation, electricity stealing detection or analysis calculation of the line loss of the transformer area is improved, the abnormal line of the transformer area is found in time, and the accurate positioning is realized.
It is understood that the freeze data is hour freeze data, 15 minute freeze data, or minute freeze data.
It can be understood that the equation set construction module performs separate construction based on phases when constructing a loop impedance equation set of a topology region, where the constructed loop impedance equation set is:
Where V s represents the voltage data of the head node, U n represents the voltage data of the n-th end node, I n represents the current data of the n-th end node, Z n represents the line impedance value between the n-th end node and the head node, and Z pn represents the common branch impedance value between the p-th end node and the n-th end node to the head node.
It can be appreciated that the calculation module establishes, for each equation in the loop impedance equation set, a target planning problem based on frozen data of the corresponding node at two times:
Wherein, the superscript ta represents the frozen data at the time ta, the superscript tb represents the frozen data at the time tb, Z pi represents the impedance value of the common branch from the p-th end node and the i-th end node to the head node, and DeltaU represents the voltage difference between the head node and the p-th end node obtained by optimization solution at the time ta;
Solving the planning problem to obtain an optimal extremum solution delta U, if Epsilon is a preset precision threshold, which means that the solution value reaches the precision requirement, and the value of the P-th unknown quantity corresponding to the optimal solution is found, namely, the line impedance value Z p between the first node and the P-th end node;
and repeating the process, and solving to obtain the line impedance value from the head node to each end node.
It can be appreciated that when the calculation module performs the objective planning problem solving, the frozen data at the moment when the large current occurs in the end node is selected for solving.
It is understood that the real-time computing system for the impedance of the line of the transformer area further comprises:
The optimization calculation module is used for calculating to obtain a plurality of line impedance values from each end node to the head node in the topological area, setting a value interval according to the numerical conditions of the line impedance values, equally dividing the value interval into a plurality of subintervals, screening the subinterval with the largest line impedance value, calculating to obtain the line impedance value average value of the subintervals, and taking the line impedance value average value as the final line impedance value from the end node to the head node.
It can be understood that each module in the system of this embodiment corresponds to each step of the above method embodiment, so that the specific working process and working principle of each module are not described herein, and reference is made to the above method embodiment.
In addition, another embodiment of the present invention also provides an electronic device, including a processor and a memory, where the memory stores a computer program, and the processor is configured to execute the steps of the method described above by calling the computer program stored in the memory.
In addition, another embodiment of the present invention also provides a computer readable storage medium storing a computer program for performing real-time calculation of a district line impedance, the computer program executing the steps of the method as described above when running on a computer.
Forms of general computer-readable storage media include: a floppy disk (floppy disk), a flexible disk (flexible disk), hard disk, magnetic tape, any other magnetic medium suitable for use with a hard disk, a CD-ROM, any other optical medium, punch cards, paper tape (PAPER TAPE), any other physical medium with patterns of holes, random Access Memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), FLASH erasable programmable read-only memory (FLASH-EPROM), any other memory chip or cartridge, or any other medium from which a computer can read. The instructions may further be transmitted or received over a transmission medium. The term transmission medium may include any tangible or intangible medium that may be used to store, encode, or carry instructions for execution by a machine, and includes digital or analog communications signals or their communications with intangible medium that facilitate communication of such instructions. Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise a bus for transmitting a computer data signal.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. The real-time calculation method for the line impedance of the transformer area is characterized by comprising the following steps of:
Selecting a topological area needing impedance calculation, finding out head and tail nodes in the topological area, and acquiring freezing data of the head node and all tail nodes;
Constructing a loop impedance equation set of the topological area; the constructed loop impedance equation set is:
Where V s represents the voltage data of the head node, U n represents the voltage data of the n-th end node, I n represents the current data of the n-th end node, Z n represents the line impedance value between the n-th end node and the head node, and Z pn represents the common branch impedance value between the p-th end node and the n-th end node to the head node;
Establishing a target planning problem and solving the target planning problem based on the obtained frozen data to obtain a line impedance value between each end node and the head node in the topological area;
The step of establishing a target planning problem and solving the target planning problem based on the obtained frozen data to obtain the impedance value of the line between each end node and the head node in the topological area comprises the following steps:
For each equation in the loop impedance equation set, establishing a target planning problem based on frozen data of the corresponding node at two moments:
Wherein, the superscript ta represents the frozen data at the time ta, the superscript tb represents the frozen data at the time tb, Z pi represents the impedance value of the common branch from the p-th end node and the i-th end node to the head node, and DeltaU represents the voltage difference between the head node and the p-th end node obtained by optimization solution at the time ta;
Solving the planning problem to obtain an optimal extremum solution delta U, if Epsilon is a preset precision threshold, which means that the solution value reaches the precision requirement, and the value of the P-th unknown quantity corresponding to the optimal solution is found, namely, the line impedance value Z p between the first node and the P-th end node;
and repeating the process, and solving to obtain the line impedance value from the head node to each end node.
2. The method for calculating the line impedance of a station area in real time according to claim 1, wherein the freezing data is hour freezing data, 15 minutes freezing data or minutes freezing data.
3. The method of real-time computation of cell line impedance according to claim 1, wherein the phase-based separate construction is performed when constructing the loop impedance equation set of the topology region.
4. The method for real-time calculation of district line impedance according to claim 1 wherein when solving a target planning problem, frozen data at the moment when a large current occurs at an end node is selected for solving.
5. The method for calculating the impedance of the line of the station area in real time according to any one of claims 1 to 4, further comprising:
Calculating to obtain a plurality of line impedance values between each end node and the head node in the topological area, setting a value interval according to the numerical conditions of the line impedance values, equally dividing the value interval into a plurality of subintervals, screening the subinterval with the largest line impedance value, calculating to obtain the line impedance value average value of the subinterval, and taking the line impedance value average value as the final line impedance value between the end node and the head node.
6. A real-time computing system for the impedance of a line in a station area, using the method of any one of claims 1 to 5, comprising:
the area selection module is used for selecting a topological area needing impedance calculation, finding out head and tail nodes in the topological area, and acquiring frozen data of the head node and all the tail nodes;
The equation set construction module is used for constructing a loop impedance equation set of the topological area;
and the calculation module is used for establishing a target planning problem and solving the target planning problem based on the acquired frozen data to obtain a line impedance value between each end node and the head node in the topological area.
7. An electronic device comprising a processor and a memory, said memory having stored therein a computer program for executing the steps of the method according to any of claims 1-5 by invoking said computer program stored in said memory.
8. A computer readable storage medium storing a computer program for performing real-time calculation of a cell line impedance, wherein the computer program when run on a computer performs the steps of the method according to any one of claims 1-5.
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