CN115438299A - Real-time calculation method and system for line impedance of transformer area, electronic device and storage medium - Google Patents
Real-time calculation method and system for line impedance of transformer area, electronic device and storage medium Download PDFInfo
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Abstract
The invention discloses a method and a system for calculating line impedance of a distribution room in real time, electronic equipment and a storage medium. The circuit impedance value is solved by constructing a loop impedance equation set of a topological area and establishing a target planning problem, so that the real-time calculation of any circuit impedance value of a transformer area can be realized, the influence of other circuit loads on an impedance calculation circuit is considered, the accuracy of the circuit impedance calculation is greatly improved, the accuracy of load flow calculation, electricity stealing detection or transformer area line loss analysis calculation is improved, the abnormity of the transformer area circuit can be timely found, and the accurate positioning can be realized.
Description
Technical Field
The present invention relates to the field of line impedance calculation technologies, and in particular, to a method and a system for calculating line impedance of a distribution room in real time, an electronic device, and a computer-readable storage medium.
Background
With the development of the power industry and the increase of power consumption requirements, the digitization and the intellectualization degree of a power grid are higher and higher, and various electric quantity data are gradually improved. However, the line impedance value of the distribution area is generally a line impedance parameter marked on a drawing in the planning of distribution network design, and when the line is aged, leaked or stolen, if the initial impedance parameter is adopted to perform load flow calculation, electricity stealing detection or line loss analysis and calculation of the distribution area, the current loss and the electricity stealing are often inaccurate, so that the actual line loss and the electric energy are much higher than the calculated line loss, and therefore, the calculation of the actual line impedance of the distribution area is necessary. Patent CN202010053775.0 previously filed by the present applicant discloses a method for calculating a power supply line impedance value based on load jump, which eliminates the influence of the error of the electric meter itself and the error of the influence quantity on the calculation result by obtaining the voltage measurement value and the current measurement value of two branch units before and after load jump and calculating the line impedance value between the two branch units based on the difference of the measurement values. However, this method needs to calculate the impedance based on the electrical quantity data before and after the load jump occurs, and cannot realize the real-time calculation of the line impedance of the transformer area.
Disclosure of Invention
The invention provides a method and a system for calculating impedance of a transformer area line in real time, electronic equipment and a computer readable storage medium, and aims to solve the technical problems that the existing impedance calculation method cannot realize the real-time calculation of the impedance of the transformer area line and the accuracy of a calculation result is poor due to the fact that the influence of other line loads is not considered.
According to an aspect of the present invention, there is provided a method for calculating line impedance of a distribution room in real time, including the following steps:
selecting a topological area needing impedance calculation, finding out first and last nodes in the topological area, and acquiring freezing data of the first nodes and all the tail end nodes;
constructing a loop impedance equation set of the topological area;
and establishing a target planning problem and solving based on the acquired freezing data to obtain a line impedance value between each tail end node and a head node in the topological area.
Further, the freeze data is hourly freeze data, 15 minute freeze data, or minute freeze data.
Further, separate construction based on phase is performed when constructing the loop impedance equation set for the topological area.
Further, the constructed loop impedance equation is:
wherein, V s Voltage data representing head node, U n Voltage data representing the nth end node, I n Current data representing the nth end node, Z n Representing the line impedance value, Z, between the nth end node and the first node pn Representing the common branch impedance values of 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 acquired freezing data to obtain an impedance value of a line from each end node to a head node in the topological area specifically includes:
for each equation in the loop impedance equation set, a target planning problem is established based on frozen data of the corresponding node at two moments:
the superscript ta denotes the frozen data at time ta, the superscript tb denotes the frozen data at time tb, and Z pi Representing the p-th end node and the i-th end node to the headThe common branch impedance value of the nodes, delta U represents the voltage difference value of the first node and the p-th tail end node at the time ta obtained by optimization solution;
solving the planning problem to obtain an optimal extremum solution delta U if
If epsilon is a preset precision threshold, the solution value meets the precision requirement, and the value of the P-th unknown quantity corresponding to the optimal solution, namely the line impedance value Z between the first node and the P-th end node, is found p ；
And repeating the process, and solving to obtain the line impedance value between the head node and each tail end node.
Further, when the target planning problem is solved, frozen data of the end node at the moment when the large current occurs is selected for solving.
Further, the following contents are also included:
calculating to obtain a plurality of line impedance values between each tail end node and the first node in the topological area, setting a value section according to the numerical value condition of the plurality of line impedance values, dividing the value section into a plurality of subintervals, screening the subintervals with the largest number of line impedance values, calculating to obtain the average value of the line impedance values of the subintervals, and taking the average value as the final line impedance value between the tail end node and the first node.
In addition, the invention also provides a real-time calculation system for the line impedance of the transformer area, which comprises:
the area selection module is used for selecting a topological area needing impedance calculation, finding out the first and last nodes in the topological area and acquiring the freezing data of the first node and all the last nodes;
the equation set building module is used for building 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 freezing data to obtain a line impedance value between each tail end node and the head node in the topological area.
In addition, the present 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 for storing a computer program for performing real-time calculation of line impedance of a distribution area, where the computer program executes the steps of the method described above when the computer program runs on a computer.
The invention has the following effects:
the method for calculating the line impedance of the distribution room in real time comprises the steps of firstly selecting a topological area needing impedance calculation, finding out the first node and the last node of the topological area, acquiring freezing data of the first node and all the tail end nodes, then constructing a loop impedance equation set of the topological area, then establishing a target planning problem and solving based on the acquired freezing data, and thus obtaining the line impedance value between each tail end node and the first node in the topological area. According to the real-time calculation method for the line impedance of the transformer area, the line impedance value is solved by constructing a loop impedance equation set of a topological area and establishing a target planning problem, the line impedance value is calculated based on frozen data at any moment, the real-time calculation of the impedance value of any line of the transformer area can be realized, and in the constructed loop impedance equation set, the influence of other line loads on an impedance calculation line is considered, so that the accuracy of the line impedance calculation is greatly improved, the accuracy of load flow calculation, electricity stealing detection or line loss analysis calculation of the transformer area is improved, the abnormality of the line of the transformer area is favorably found in time, and 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, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic flow chart of a method for calculating line impedance of a distribution room in real time according to a preferred embodiment of the present invention.
Fig. 2 is a schematic diagram of a line topology of a cell.
Fig. 3 is a schematic diagram of a line topology in which a topological area has only one end node in the preferred embodiment of the present invention.
Fig. 4 is a schematic diagram of a line topology with two end nodes in a topological area in a preferred embodiment of the present invention.
Fig. 5 is a schematic flow chart of a method for calculating line impedance of a distribution room in real time according to another embodiment of the present invention.
Fig. 6 is a schematic block diagram of a real-time calculation system for line impedance of a distribution room according to another embodiment of the present invention.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be practiced in many different ways, which are defined and covered by the following.
As shown in fig. 1, a preferred embodiment of the present invention provides a method for calculating line impedance of a distribution room in real time, which includes the following steps:
step S1: selecting a topological area needing impedance calculation, finding out first and last nodes in the topological area, and acquiring freezing data of the first nodes and all the tail end nodes;
step S2: constructing a loop impedance equation set of the topological area;
and step S3: and establishing a target planning problem and solving based on the acquired freezing data to obtain a line impedance value between each tail end node and a head node in the topological area.
It can be understood that, in the method for calculating line impedance of a distribution room in real time according to this embodiment, a topological area that needs to be subjected to impedance calculation is selected, the first and last nodes of the topological area are found, the freezing data of the first node and all the end nodes are obtained, a loop impedance equation set of the topological area is then constructed, a target planning problem is then established, and solution is performed based on the obtained freezing data, so that a line impedance value between each end node and 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 line impedance value is solved by constructing a loop impedance equation set of a topological area and establishing a target planning problem, the line impedance value is calculated based on frozen data at any moment, the real-time calculation of the impedance value of any line of the transformer area can be realized, and in the constructed loop impedance equation set, the influence of other line loads on an impedance calculation line is considered, so that the accuracy of the line impedance calculation is greatly improved, the accuracy of load flow calculation, electricity stealing detection or line loss analysis calculation of the transformer area is improved, the abnormality of the line of the transformer area is favorably found in time, and accurate positioning is realized.
It will be appreciated that the block line impedance calculation needs to be done based on the known block line topology, i.e. the block has a complete or partially complete topology of summary table-branch-meter box terminal-household table, as shown in fig. 2. In step S1, the user may select a topology region for performing impedance calculation according to needs, which may be a complete topology region of the total table-user table or a local topology region of the branch-user table. And then, finding out the head node and the tail node in the selected topological area according to the platform area line topological structure, wherein the topological area generally comprises one head node and a plurality of tail nodes. Alternatively, the head node typically selects the summary table or the first level of branch units, while the end node typically selects the meter box terminal or the household table. And then, acquiring freezing data of the first node and all the last nodes, wherein the type of the freezing data is hour freezing data, 15-minute freezing data or minute freezing data, and the content of the freezing data specifically comprises voltage data and current data. Wherein, the hour freezing data refers to 24-point freezing data in one day, the 15-minute freezing data refers to 96-point freezing data in one day, and the minute freezing data refers to 60-point second-level freezing data in one minute. The user can select the type of the frozen data according to needs, for example, when the hourly frozen data or the 15-minute frozen data are selected, daily impedance calculation can be performed so as to perform line loss calculation with a large time dimension and analyze the line aging condition of the transformer area, and when the minute frozen data are selected, real-time impedance calculation can be performed, so that the abnormity of the transformer area line can be found in time and accurate positioning can be performed, and manpower and material resources consumed by manual line inspection are saved.
It can be understood that, in the step S2, the loop impedance equation set is constructed as follows:
wherein, V s Voltage data representing head node, U n Voltage data representing the nth end node, I n Current data representing the nth end node, Z n Representing the line impedance value, Z, between the nth end node and the first node pn Representing the common branch impedance values of the p-th end node and the n-th end node to the head node.
It will be appreciated that the loop impedance equations for the topological region are constructed separately based on phase. For example, when the end node of the topology region is a meter box terminal, A, B, C three phases of the head node are required to be respectively in one-to-one correspondence with A, B, C three phases of the meter box terminal, and when the end node of the topology region is a house table, the head node is divided into A, B, C three phases, and then calculation is performed according to all the house tables of the phase under each phase.
Taking the topological area from the general table to the user table, and the phase A as an example, the calculation is performed by periodically freezing the voltage U and the current I.
When the topological area has only a single end node, as shown in fig. 3, the topological area has only one loop, and based on kirchhoff's voltage law, it can be known that:
V s ＝Z 11 I 1
wherein, V s Voltage, I, representing a summary 1 Current, Z, representing the household meter 1 11 The sum of the line impedance from the summary table to the meter 1 and the load impedance of the meter 1 is shown.
When the topology area has two end nodes, as shown in fig. 4, the topology area has three lines, which are: a line from the middle node to the user table 1, a line from the middle node to the user table 2, and a line from the middle node to the general table (i.e. a common branch from the user table 1 and the user table 2 to the general table). According to kirchhoff's voltage law, the sum of voltage drops on elements and lines on each loop from table 1 of the summary table to table 2 is equal to the algebraic sum of electromotive force of the summary table, and loop equations from the summary table to table 1 and from table 2 can be listed respectively:
wherein, I In all ＝I 1 +I 2 Denotes the current of the common branch, Z 12 Representing the impedance of the common branch, Z In 1 Representing the sum of the line impedance value of the middle node to the meter 1 and the load impedance value of the meter 1, Z In 2 Represents the sum of the line impedance value of the middle node to the user table 2 and the load impedance value of the user table 2.
Will I In total ＝I 1 +I 2 Substituting the above equation system can obtain:
recombining to obtain:
let Z 11 ＝(Z 12 +Z In 1 )、Z 22 ＝(Z 12 +Z In 2 )，Z 11 Representing the sum of the line impedance of the meter 1 to the summary table and the load impedance of the meter 1, Z 22 The sum of the line impedance of the meter 2 to the summary table and the load impedance of the meter 2, also called self-impedance, is represented. Thereby obtaining:
when the topological region has n user tables, the method can obtain the following results based on kirchhoff's voltage law:
wherein Z is ii Representing the self-impedance, Z, of the ith meter ij And (i ≠ j) is mutual impedance and represents the impedance of a common branch from the ith user table and the jth user table to the summary table.
Then, the self-impedance Z ii Splitting into: z ii ＝Z l +Z i Wherein Z is l Representing the load impedance, Z, of the ith meter i Representing the line impedance between the ith meter to the summary. Adding node current to obtain: z ii I i ＝Z l I i +Z i I i Thereby obtaining: z ii I i ＝U i +Z i I i . Substituting it into the above equation set table to obtain U i Moving to the left results in a set of loop impedance equations for the topological region:
wherein, V s Voltage data, U, representing a summary table n Voltage data representing the nth meter, I n Current data representing the nth meter, Z n Representing the line impedance value, Z, between the nth meter and the summary pn And representing the common branch impedance value from the p-th user table and the n-th user table to the total table. Wherein Z is n Namely the solution quantity to be solved.
It can be understood that the first node may also select the first-level branch unit or the second-level branch unit, and the end node may also select the user list terminal, and the construction process is consistent with the above process.
It can be understood that, in the step S3, the step of establishing the target planning problem and solving the target planning problem based on the acquired freezing data to obtain the impedance value of the line from each end node to the head node in the topology region specifically includes:
for each equation in the loop impedance equation set, a target planning problem is established based on frozen data of the corresponding node at two moments:
the superscript ta denotes frozen data at time ta, the superscript tb denotes frozen data at time tb, and Z pi Expressing the common branch impedance values from the p-th end node and the ith end node to the head node, wherein delta U represents the voltage difference value of the head node and the p-th end node at the time ta obtained by optimization solution;
solving the planning problem to obtain an optimal extremum solution delta U if
If epsilon is a preset precision threshold, the solution value meets the precision requirement, and the value of the P unknown quantity corresponding to the optimal solution, namely the line impedance value Z between the head node and the P tail end node, is found p ；
And repeating the process, and solving to obtain the line impedance value between the head node and each tail end node.
Specifically, take the equation related to the end node p in the loop impedance equation set constructed in step S2 as an example, i.e., for equation V s -U p ＝Z p1 I 1 +Z p2 I 2 +...+Z p I p +...+Z pn I n Is solved for n impedance values. For an equation with a plurality of unknowns, a conventional method is to establish a multi-element linear equation set by a plurality of groups of data at different moments for solving, and the method has the advantages of great calculated amount, low efficiency and poor solving effect. Therefore, the invention adopts the mode of establishing a target planning problem and setting a target function and a constraint condition to solve. First, the objective function determination of the planning problem requires oneAnd (3) time data, establishing a series of constraint conditions according to the characteristic that the impedance is greater than 0 and the mutual impedance between the first node and the tail end node p, wherein the line impedance is greater than or equal to the mutual impedance between the nodes, and the optimal solution obtained by solving the target planning problem has certain contingency. Compared with the solution of a linear equation set, the solution of a single equation is huge, the range of the solution is reduced by increasing the number of the equations, and finally, a unique solution is obtained when the number of the equations is equal to the number of the unknowns. Therefore, data at more than one moment is required to participate in the target planning problem, so data at other moments are added into the constraint condition, and after equations at two or more moments are added into the constraint condition (at this time, data at three or more moments are used in total), the planning problem is not solved because of excessive constraint conditions.
For example, data at two times (time ta and time tb) are selected to construct an equation, specifically:
the superscript ta denotes data at time ta, and the superscript tb denotes data at time tb.
Due to end node current I 1 ～I n And the head node I s The following relationships exist:
I 1 ，I 2 ，...，I n ≤I s
the impedance of the end node p at times ta, tb is then:
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:
then, according to the line impedance characteristics, 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:
Z p -Z pi ≥0,i＝1,2,...,n,i≠p
further, from the impedance characteristics: z is a linear or branched member p ,Z pi ≥0,i＝1,2,...,n,i≠p。
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 the p-th unknown quantity value corresponding to the optimal solution, namely the line impedance value Z from the end node p to the head node is found out p 。
And (4) aiming at other end nodes, repeating the target planning solution to obtain the line impedance values from all the end nodes to the head node.
Optionally, when the target planning problem is solved, frozen data of the end node at the moment when a large current occurs is selected for solving. Since, according to ohm's law, the larger the current in the line, the larger the voltage drop on the line, generally, the wire impedance is in the order of m Ω, the 1A current can only generate 1mV voltage drop under the 1m Ω impedance, and the freezing voltage of the summary table, the household table and the terminals therebetween is generally in the order of 0.1V or 0.01V, i.e. the minimum voltage drop can only reach 0.01V. If the current of the selected line is too small, the voltage drop is extremely low, and the voltage drop caused by the line impedance cannot be reflected in the frozen data based on the limitation of voltage precision, so that the frozen data at the moment when the terminal node generates the large current is preferably selected when the target planning problem is solved, 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 line impedance in real time in a transformer area further includes the following steps:
and step S4: calculating to obtain a plurality of line impedance values between each tail end node and the first node in the topological area, setting a value range according to the numerical conditions of the plurality of line impedance values, equally dividing the value range into a plurality of subintervals, screening the subintervals with the largest number of line impedance values, calculating to obtain the mean value of the line impedance values of the subintervals, and taking the mean value as the final line impedance value between the tail end node and the first node.
For example, when the freezing data of 15 minutes at 96 points in a day is selected, the freezing data of each day is searched for a time point sequence t satisfying the voltage and current condition 1 ,t 2 ,...,t L And L (L is less than or equal to 96) time points. Respectively let ta = t i ，tb＝t j And (i ≠ j) traversing all time points, and calculating a plurality of line impedance values from each tail end node to the head node according to the step S3, wherein the line impedance value obtained by each tail end node is required to be not less than eta. Then, a proper value interval is selected according to the line impedance value obtained by each end node[A,B]The value interval [ A, B ]]Equally dividing the impedance value into psi sections, namely equally dividing the impedance value into psi subintervals, and taking the average value of the impedance values of the subintervals with the largest falling value as the line impedance value from the tail end node to the head node. Wherein, the values of η and Ψ may be set as desired.
Alternatively, the freezing data of 60 minutes and second level is selected, and the time point sequence t meeting the voltage and current condition is searched from the data of every minute 1 ,t 2 ,...,t l And l (l is less than or equal to 96) time points. Let ta = t respectively i ，tb＝t j And (i ≠ j) traversing all time points, and calculating a plurality of line impedance values from each tail end node to the head node according to the step S3, wherein the line impedance value obtained by each tail end node is required to be not less than gamma. Then, a proper value interval [ a, b ] is selected according to the line impedance value obtained by each end node]Will take the value interval [ a, b]And equally dividing into delta sections, namely equally dividing into delta subintervals, and taking the average value of the impedance values of the subintervals with the largest falling value as the line impedance value from the tail end node to the head node. The values of γ and δ may be set as needed.
It can be understood that by performing interval division on a plurality of impedance values acquired by each end node, a sub-interval containing the largest number of line impedance values is screened out, and the line impedance value mean value of the sub-interval is used as the final line impedance value between the end node and the head node, so that the influence of accidental errors can be reduced, and the accuracy of line impedance calculation in a transformer area can be further improved.
In addition, as shown in fig. 6, another embodiment of the present invention further provides a system for calculating line impedance of a distribution room in real time, preferably using the method described above, including:
the area selection module is used for selecting a topological area needing impedance calculation, finding out the first and last nodes in the topological area and acquiring the freezing data of the first node and all the last nodes;
the system of equations constructing module is used for constructing a loop impedance system 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 freezing data to obtain a line impedance value between each tail end node and a head node in the topological area.
It can be understood that, in the platform area line impedance real-time calculation system of this embodiment, a topological area that needs to be subjected to impedance calculation is selected first, the first and last nodes of the topological area are found, the freezing data of the first node and all the end nodes are obtained, then a loop impedance equation set of the topological area is constructed, then a target planning problem is established and solution is performed based on the obtained freezing data, so that a line impedance value between each end node and the first node in the topological area is obtained. The real-time calculation system for the line impedance of the transformer area, disclosed by the invention, can realize the real-time calculation of the impedance value of any line in the transformer area by constructing a loop impedance equation set of a topological area and establishing a target planning problem to solve the impedance value of the line and calculating the impedance value of the line based on frozen data at any moment, and moreover, in the constructed loop impedance equation set, the influence of other line loads on an impedance calculation line is considered, so that the accuracy of the calculation of the line impedance is greatly improved, the accuracy of load flow calculation, electricity stealing detection or line loss analysis and calculation of the transformer area is improved, the abnormality of the line in the transformer area is favorably found in time, and the accurate positioning is realized.
It is understood that the freeze data is hourly freeze data, 15 minute freeze data, or minute freeze data.
It can be understood that the equation set building module is separately built based on the phase when building the loop impedance equation set of the topological area, and the built loop impedance equation set is as follows:
wherein, V s Voltage data representing head node, U n Voltage data representing the nth end node, I n Current data representing the nth end node, Z n Representing the line impedance value, Z, between the nth end node and the first node pn Representing the common branch impedance values of the p-th end node and the n-th end node to the head node.
It is to be understood that the calculation module establishes a target planning problem for each of the loop impedance equations based on the frozen data of the corresponding node at two times:
the superscript ta denotes frozen data at time ta, the superscript tb denotes frozen data at time tb, and Z pi Expressing the common branch impedance values from the p-th end node and the ith end node to the head node, and expressing the voltage difference value at the time ta between the head node and the p-th end node obtained by optimization solution by delta U;
solving the planning problem to obtain an optimal extremum solution delta U if
If epsilon is a preset precision threshold, the solution value meets the precision requirement, and the value of the P-th unknown quantity corresponding to the optimal solution, namely the line impedance value Z between the first node and the P-th end node, is found p ；
And repeating the process, and solving to obtain the line impedance value between the head node and each tail end node.
It can be understood that when the calculation module is used for solving the target planning problem, the frozen data of the tail end node at the moment when the large current occurs is selected for solving.
It can be understood that the real-time calculation system for line impedance of the platform area further comprises:
and the optimization calculation module is used for calculating and obtaining a plurality of line impedance values between each end node and the first node in the topological area, setting a value interval according to the numerical conditions of the plurality of line impedance values, dividing the value interval into a plurality of subintervals, screening the subintervals with the largest number of line impedance values, calculating and obtaining the line impedance value mean value of the subintervals, and taking the line impedance value mean value as the final line impedance value between the end node and the first node.
It can be understood that each module in the system of this embodiment corresponds to each step of the foregoing method embodiment, and therefore, detailed working processes and working principles of each module are not described herein again, and reference may be made to the foregoing method embodiment.
In addition, another embodiment of the present invention further provides an electronic device, which includes a processor and a memory, wherein the memory stores a computer program, and the processor is used for executing the steps of the method described above by calling the computer program stored in the memory.
In addition, another embodiment of the present invention further provides a computer-readable storage medium for storing a computer program for performing real-time calculation of line impedance of a station area, where the computer program performs the steps of the method described above when the computer program runs on a computer.
Typical forms of computer-readable storage media include: floppy disk (floppy disk), flexible disk (flexible disk), hard disk, magnetic tape, any of its magnetic media, CD-ROM, any of the other optical media, punch cards (punch cards), paper tape (paper tape), any of the other physical media 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 of the other memory chips or cartridges, or any of the other media from which a computer can read. The instructions may further be transmitted or received by a transmission medium. The term transmission medium may include any tangible or intangible medium that is operable to store, encode, or carry instructions for execution by the machine, and includes digital or analog communications signals or intangible medium to facilitate communication of such instructions. Transmission media include 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 a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A real-time calculation method for line impedance of a transformer area is characterized by comprising the following steps:
selecting a topological area needing impedance calculation, finding out first and last nodes in the topological area, and acquiring freezing data of the first nodes and all the last nodes;
constructing a loop impedance equation set of the topological area;
and establishing a target planning problem and solving based on the acquired freezing data to obtain a line impedance value between each tail end node and a head node in the topological area.
2. The method of real-time line impedance calculation for a distribution room of claim 1, wherein the freeze data is hourly freeze data, 15-minute freeze data, or minute freeze data.
3. The method of real-time line impedance computation of claim 1, wherein the loop impedance equations for the topological area are constructed separately based on phase.
4. The method for real-time calculation of line impedance of a distribution room of claim 1, wherein the set of loop impedance equations is constructed by:
wherein, V s Voltage data representing head node, U n Voltage data representing the nth end node, I n Current data representing the nth end node, Z n Representing the line impedance value, Z, between the nth end node and the first node pn Representing the p-th end node and the n-th end node to the headA common branch impedance value of the node.
5. The method for calculating line impedance of a distribution room in real time according to claim 4, wherein the step of establishing a target planning problem and solving the target planning problem based on the acquired freezing data to obtain the impedance value of the line from each end node to the head node in the topological area specifically comprises the steps of:
for each equation in the loop impedance equation set, a target planning problem is established based on the frozen data of the corresponding node at two moments:
the superscript ta denotes the frozen data at time ta, the superscript tb denotes the frozen data at time tb, and Z pi Expressing the common branch impedance values from the p-th end node and the ith end node to the head node, wherein delta U represents the voltage difference value of the head node and the p-th end node at the time ta obtained by optimization solution;
solving the planning problem to obtain an optimal extremum solution delta U if
If epsilon is a preset precision threshold, the solution value meets the precision requirement, and the value of the P-th unknown quantity corresponding to the optimal solution, namely the line impedance value Z between the first node and the P-th end node, is found p ；
And repeating the process, and solving to obtain the line impedance value between the head node and each tail end node.
6. The method for calculating line impedance of a distribution room of claim 5, wherein when solving the objective planning problem, frozen data at the moment when a large current occurs at the end node is selected for solving.
7. The method for real-time calculation of line impedance of a distribution room of any one of claims 1 to 6, further comprising:
calculating to obtain a plurality of line impedance values between each tail end node and the first node in the topological area, setting a value section according to the numerical value condition of the plurality of line impedance values, dividing the value section into a plurality of subintervals, screening the subintervals with the largest number of line impedance values, calculating to obtain the average value of the line impedance values of the subintervals, and taking the average value as the final line impedance value between the tail end node and the first node.
8. A real-time counter system for line impedance in a distribution room, comprising:
the area selection module is used for selecting a topological area needing impedance calculation, finding out the first and last nodes in the topological area and acquiring the freezing data of the first node and all the last nodes;
the equation set building module is used for building 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 freezing data to obtain a line impedance value between each tail end node and a head node in the topological area.
9. An electronic device, comprising a processor and a memory, the memory having a computer program stored therein, the processor being adapted to perform the steps of the method according to any of claims 1 to 7 by invoking the computer program stored in the memory.
10. A computer-readable storage medium for storing a computer program for performing a real-time calculation of a line impedance of a cell, wherein the computer program, when run on a computer, performs the steps of the method according to any one of claims 1 to 7.
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| CN112560239A (en) * | 2020-12-03 | 2021-03-26 | 广东电网有限责任公司云浮供电局 | Method and system for calculating line impedance of transformer area and computer readable storage medium |
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