A method for checking line safety margin

Abstract

The invention discloses a line safety margin verification method, which relates to the technical field of electric power safety margin. The method comprises the following steps: determining an optimal load rate that satisfies power supply reliability and network structure without considering a margin for load growth; calculating a line load growth rate according to an average load rate that has decreased in recent years; calculating an optimal line load rate considering a margin for load growth according to the line load growth rate; calculating an average current reference value for next year according to the average daily current of the line last year and the optimal line load rate considering a margin for load growth; and calculating a line safety margin according to the rated current carrying capacity and the average current reference value for next year. Thus, the line safety margin calculated by combining the data of recent years with the optimal line load rate is more accurate, thereby providing data support for monitoring the operation status of the line.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power safety margin, and in particular relates to a line safety margin verification method. Background Art

[0002] In recent years, the big data processing technology of distribution network has been increasingly concerned and valued by international academic organizations such as IEEE and CIGRE. The main research hotspots are currently focused on: providing effective storage and indexing mechanisms for massive data in distribution networks, establishing an efficient data processing platform that meets the needs of active management and operation of distribution networks, so as to accurately predict and evaluate the operating status of distribution networks, and then build an efficient distribution network energy dispatching system, and provide reliable control and operation optimization technology.

[0003] The operating reserve of the power system is mainly set up to ensure the system frequency quality requirements after the occurrence of anticipated faults (including generator output fluctuations, load fluctuations, short circuits, tripping and DC interlocking, etc.). Therefore, it is necessary to continuously monitor the operating reserve during the operation of the power system and evaluate its actual ability to ensure the system frequency quality.

[0004] However, the existing line safety margin calculation is inaccurate, so a line safety margin verification method is needed to verify the line safety margin. Summary of the invention

[0005] The purpose of the present invention is to provide a line safety margin verification method, thereby overcoming the disadvantage of inaccurate line safety margin verification in the prior art.

[0006] To achieve the above object, the present invention provides a line safety margin verification method, comprising the following steps:

[0007] Determine the optimal load rate that meets power supply reliability and network structure without considering the margin left for load growth;

[0008] Calculate the line load growth rate based on the average load rate of the line that has decreased in recent years;

[0009] Calculating the optimal load rate of the line taking into account the margin left for load growth according to the line load growth rate;

[0010] Calculate the average current reference value for next year based on the average daily current of the line last year and the optimal load factor of the line with a margin for load growth;

[0011] Calculate the line safety margin based on the rated current carrying capacity and the average current reference value for the next year.

[0012] Preferably, the optimal line load rate that satisfies power supply reliability and network structure is determined according to the line wiring mode and the power supply area type.

[0013] Preferably, the line load growth rate is calculated based on the average load rate of the line that decreases within 3 years.

[0014] Preferably, the calculation formula for calculating the average load rate to calculate the line load growth rate v is:

[0015]

[0016] In the above formula, l6, l7, l8 represent the average load factors in June, July and August respectively, and t, t-1, t-2 represent the data of the line last year, the year before last and the previous three years respectively.

[0017] Preferably, the expression for calculating the optimal line load rate taking into account the margin left for load growth according to the line load growth rate is:

[0018]

[0019] In the above formula, β optimal is the optimal load factor of the line without considering the margin left for load growth; β' optimal It is the optimal load rate of the line with a margin for load growth; v is the line load growth rate; n is the load growth time considered, unit: year.

[0020] Preferably, the daily average current reference value I for next year is calculated based on the daily average current of the line last year and the optimal load rate of the line under the condition of considering the margin left for load growth. optimal The expression is:

[0021]

[0022] In the above formula, I average is the daily average current of the line last year, β optimal The optimal load rate of the line taking into account the margin left for load growth.

[0023] Preferably, the expression of the line safety margin is:

[0024]

[0025] In the above formula, S is the line safety margin, I optimal is the reference value of the average daily current for the next year, and I is the rated current carrying capacity of the line.

[0026] Preferably, the line operation status is judged according to the line safety margin.

[0027] Compared with the existing technology, the present invention has the following beneficial effects:

[0028] The line safety margin verification method provided by the present invention determines the optimal load rate that satisfies power supply reliability and network structure without considering the margin left for load growth; calculates the line load growth rate based on the average load rate of the line that has decreased in recent years; calculates the line optimal load rate based on the line load growth rate considering the margin left for load growth; calculates the average current reference value for next year based on the daily average current of the line last year and the line optimal load rate considering the margin left for load growth; calculates the line safety margin based on the rated current carrying capacity and the average current reference value for next year, so that the line safety margin calculated by combining the data of recent years with the line optimal load rate is more accurate, providing data support for monitoring the operating status of the line. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 The present invention is a flow chart of a line safety margin verification method. DETAILED DESCRIPTION

[0031] The following is a clear and complete description of the technical solutions in the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, the line safety margin verification method provided by the present invention includes:

[0033] S1. Determine the optimal load rate that satisfies power supply reliability and network structure without considering the margin left for load growth;

[0034] S2. Calculate the line load growth rate based on the average load rate of the line that has decreased in recent years;

[0035] S3, calculating the optimal load rate of the line taking into account the margin left for load growth according to the line load growth rate;

[0036] S4. Calculate the average current reference value for next year based on the average daily current of the line last year and the optimal load factor of the line with a margin for load growth;

[0037] S5. Calculate the line safety margin based on the rated current carrying capacity and the average current reference value for next year.

[0038] The above-mentioned line safety margin verification method determines the optimal load rate that meets the power supply reliability and network structure without considering the margin left for load growth; calculates the line load growth rate based on the average load rate of the line that has decreased in recent years; calculates the optimal line load rate considering the margin left for load growth based on the line load growth rate; calculates the average current reference value for next year based on the line's average daily current last year and the line's optimal load rate considering the margin left for load growth; calculates the line safety margin based on the rated current carrying capacity and the average current reference value for next year, so that the line safety margin calculated through the data of recent years combined with the line's optimal load rate is more accurate, providing data support for monitoring the operating status of the line.

[0039] In one embodiment, the network architecture is a power distribution network, including substations, lines and connected distributed power sources.

[0040] In one of the embodiments, in step S1, an optimal line load rate that satisfies power supply reliability and network structure is determined according to the line wiring mode and the power supply area type.

[0041] Specifically, the optimal load rate of 10kV line is set according to the Technical Guidelines for Distribution Network (Q / GDW10370), the Technical Guidelines for Distribution Network Planning and Design (Q / GDW1738) and the Distribution Network Operation and Maintenance Regulations (Q / GDW1519), and then adjusted through research and funding methods.

[0042] In one embodiment, the line load growth rate is calculated based on the average load rate of the line that decreases within three years.

[0043] In one embodiment, the calculation formula for calculating the line load growth rate v of the average load rate is:

[0044]

[0045] In the above formula, l6, l7, l8 represent the average load factors in June, July and August respectively, and t, t-1, t-2 represent the data of the line last year, the year before last and the previous three years respectively.

[0046] In one embodiment, the expression for calculating the optimal load rate of the line considering the margin left for load growth according to the line load growth rate is:

[0047]

[0048] In the above formula, β optimalis the optimal load rate of the line without considering the margin left for load growth (only considering the theoretical optimal load rate of the line that meets the power supply reliability and network structure); β' optimal It is the optimal load rate of the line with a margin for load growth; v is the line load growth rate; n is the load growth time considered, unit: year.

[0049] In one embodiment, the daily average current reference value I for next year is calculated based on the daily average current of the line last year and the optimal load rate of the line under the condition of considering the margin left for load growth. optimal The expression is:

[0050]

[0051] In the above formula, I average is the daily average current of the line last year, β optimal The optimal load rate of the line taking into account the margin left for load growth.

[0052] In one embodiment, the line safety margin is expressed as:

[0053]

[0054] In the above formula, S is the line safety margin, I optimal is the reference value of the average daily current for the next year, and I is the rated current carrying capacity of the line.

[0055] In one of the embodiments, the line operation status is determined based on the line safety margin.

[0056] In one of the embodiments, an early warning is given to the operating status of the line based on the line safety margin. Specifically, when the line safety margin corresponding to the line is greater than 10% and less than or equal to 20%, a warning is issued and the line needs to be closely monitored; when the line is less than 10%, a warning signal is also issued, but the line needs to be repaired.

[0057] The embodiments of the line safety margin verification method of the present invention are described in detail so that those skilled in the art can better understand the present invention:

[0058] The optimal load rate that meets the power supply reliability and network structure without considering the margin left for load growth is determined to be the optimal load rate of the 10kV line, as shown in Table 1;

[0059] Table 1 Optimal load rates of overhead lines and cable lines corresponding to the main grid structures of 10kV grid

[0060]

[0061]

[0062] If the line wiring mode is not available, the optimal line load rate can also be determined by the power supply area type (A, B, C, D) and line type (overhead line or cable line) in Table 1.

[0063] For example, if it is an overhead line in power supply area A or B, the optimal load factor of the line is 70%;

[0064] Combining the above formula (1) and formula (2), the average load rate and line load growth rate of the line in June, July and August in the past three years are calculated as shown in Table 2;

[0065] Table 2 Average load rate and load growth rate of the line in June, July and August in the past three years

[0066]

[0067] The optimal load rate of the line is determined according to the number of interconnection lines, the type of power supply area, etc., and the optimal load rate of the line is calculated by combining the line load growth rate v calculated above and the load growth time n (years) considered to obtain the optimal load rate β' of the line under the condition of considering the margin left for load growth. optimal Finally, according to the line's daily average current I average Calculate the line reference daily average current I optimal , combined with the current carrying capacity I of the line, the safety margin S of the line is calculated as shown in Table 6.

[0068] Table 6 Line safety margin calculation results

[0069]

[0070]

[0071] It can be seen from Table 6 that the safety margins of lines 2, 3, and 4 are less than or equal to 20%, indicating that the load currents of these lines are about to reach 80% of the rated current carrying capacity of the lines, and the operation of these lines should be closely monitored.

[0072] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the mobile terminal can be divided into different functional units or modules to complete all or part of the functions described above. The functional modules in the embodiment can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the modules in the above-mentioned mobile terminal can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0073] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0074] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0075] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0076] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0077] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0078] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0079] What is disclosed above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, which should be included in the protection scope of the present invention.

Claims

1. A line safety margin verification method, characterized in that: The following steps are involved: Determine the optimal load rate that meets power supply reliability and network structure without considering the margin left for load growth; Calculate the line load growth rate based on the average load rate of the line that has decreased in recent years; Calculate the line load growth rate based on the average load rate of the line that has dropped within three years; The calculation formula for calculating the average load rate line load growth rate v is: In the above formula, l6, l7, l8 represent the average load factors in June, July, and August respectively, and t, t-1, t-2 represent the data of the line last year, the year before last, and the previous three years respectively; Calculating the optimal load rate of the line taking into account the margin left for load growth according to the line load growth rate; The expression for calculating the optimal line load rate based on the line load growth rate and taking into account the margin left for load growth is: In the above formula, β optimal is the optimal load factor of the line without considering the margin left for load growth; β' optimal is the optimal load rate of the line under the condition of considering the margin left for load growth; v is the line load growth rate; n is the load growth time considered, unit: year; Calculate the average current reference value for next year based on the average daily current of the line last year and the optimal load factor of the line with a margin for load growth; Calculate the average current reference value I for next year based on the average daily current of the line last year and the optimal load rate of the line considering the margin left for load growth. optimal The expression is: In the above formula, I average is the daily average current of the line last year, β optimal The optimal load factor of the line considering the margin left for load growth; Calculate the line safety margin based on the rated current carrying capacity and the average current reference value for the next year.

2. The line safety margin verification method according to claim 1, characterized in that: Determine the optimal line load rate that meets power supply reliability and network structure based on the line wiring method and power supply area type.

3. The line safety margin verification method according to claim 1, characterized in that: The expression of the line safety margin is: In the above formula, S is the line safety margin, I optimal is the reference value of the average daily current for the next year, and I is the rated current carrying capacity of the line.

4. The line safety margin verification method according to claim 1, characterized in that: The line operation status is determined according to the line safety margin.

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