A method for optimizing UHV DC transmission curves to assist peak load regulation in receiving provinces

Abstract

The present invention relates to an ultra-high voltage direct current transmission curve optimization method for assisting the receiving province in peak load regulation, comprising the following steps: S1: obtaining the net load curve of the receiving province; S2: decomposing the agreed transmission amount according to the net load curve; S3: determining the peak and valley transmission power, duration and time period distribution in the ultra-high voltage direct current daily transmission curve according to the net load characteristics. The transmission curve optimization method proposed in the present invention can effectively alleviate the peak load regulation pressure of the receiving province, reduce the amount of abandoned wind and photovoltaic power, and reduce the electricity purchase cost of the receiving province.

Description

Technical Field

[0001] The present invention belongs to the technical field of power peak regulation, and in particular relates to an ultra-high voltage direct current transmission curve optimization method for assisting peak regulation in receiving provinces. Background Art

[0002] The UHV DC transmission channel transmits the surplus clean electricity from the sending provinces to the receiving provinces with power shortages, which plays a role in optimizing resource allocation, serving economic and social development, and promoting low-carbon transformation of energy. In recent years, the scale of DC power transmission has grown rapidly, but the transmission curve is relatively fixed, and external power does not participate in peak load regulation in the receiving provinces. Under the background of dual carbon, the scale of new energy power generation in the receiving provinces continues to grow rapidly, and the peak and valley characteristics of power load are becoming more prominent. The fixed transmission curve of external power cannot be coordinated with the "multi-peak and multi-valley" trend of the net load curve of the receiving provinces, which increases the pressure on the operation and regulation of the power system in the receiving provinces and generates high absorption costs. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a method for optimizing UHV DC transmission curves to assist peak load regulation in receiving provinces, which can effectively alleviate the peak load regulation pressure in receiving provinces, reduce the amount of abandoned wind and solar power, and at the same time reduce the electricity purchase cost in the receiving provinces.

[0004] The technical solution adopted by the present invention is: a method for optimizing UHV DC transmission curve for assisting peak load regulation in receiving provinces, comprising the following steps:

[0005] S1: Get the net load curve of the receiving province;

[0006] S2: Decompose the agreed power delivery according to the net load curve;

[0007] S3: Determine the peak and valley transmission power, duration and time period distribution in the UHV DC daily transmission curve based on the net load characteristics.

[0008] Specifically, in step S1, the formula for obtaining the net load curve of the receiving province is as follows:

[0009] P a =P l -ρ w ×G w -ρ s ×G s

[0010] Among them, P a Represents the net load curve of the receiving province, P l represents the unified electricity load curve of the receiving province in the previous year, G w Represents the installed capacity of wind power, G s represents the installed capacity of photovoltaic power generation, ρ wRepresents the hourly output coefficient of wind power, ρ s Indicates the photovoltaic hourly output coefficient.

[0011] Specifically, the step S2 is as follows:

[0012] Net load curve P a By integrating monthly and time periods, we can obtain the monthly electricity demand of the receiving provinces. The formula is as follows:

[0013]

[0014] Among them, E n It represents the monthly electricity demand of the receiving province, m represents the number of days, and n represents the month. According to the monthly electricity demand, the power supply agreement electricity is decomposed into months. The formula is as follows:

[0015]

[0016] Among them, E pro Indicates the power supply agreement quantity, E pro，n Indicates the monthly power transmission agreement electricity amount.

[0017] Specifically, in step S3, a two-step power transmission method is adopted when determining the peak and valley power transmission powers in the UHV DC daily power transmission curve, and the formula is as follows:

[0018] (1-β)×P×t+P×(24-t)=E

[0019] Among them, P is the maximum power transmission of the day. Considering the stability constraint, it does not exceed the upper limit of the designed transmission power. β is the peak-to-valley difference rate. t is the duration of low-power power transmission. E is the daily power transmission amount.

[0020] According to the above formula, the formula for the maximum power transmission on the day is as follows:

[0021]

[0022] Among them, β is obtained by analyzing the net load characteristics, and E is the monthly power transmission agreement power E pro，n Divide into daily electricity in equal proportions;

[0023] The minimum power transmission on that day is:

[0024] P0=(1-β)×P.

[0025] Specifically, in step S3, when determining the duration and time period distribution of the daily power transmission curve, the time period distribution of t needs to be optimized, specifically: the net load characteristics are analyzed on a monthly basis, with the daily average load as a benchmark, and the duration and time period distribution of the load distribution that is lower than this value are counted.

[0026] Beneficial effects of the invention: The optimization method of the invention is a power transmission curve optimization method proposed on the basis of fully considering the power load curve of the receiving provinces and the new energy power generation output curve, combined with the peak-shaving demand of the power system of the whole province. This method can effectively alleviate the peak-shaving pressure of the receiving provinces, reduce the amount of wind and photovoltaic power abandoned in the receiving provinces, and at the same time can significantly reduce the receiving power grid's power purchase cost and peak-shaving auxiliary service cost, thereby improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of the steps of the present invention;

[0028] Figure 2 A schematic diagram of the daily UHV DC power transmission curve of the present invention;

[0029] Figure 3 This is a schematic diagram of the optimized monthly UHV DC power transmission power curve described in the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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, and are specifically described in combination with the embodiments below.

[0031] like Figure 1 As shown, the present invention comprises the following steps:

[0032] S1: Get the net load curve of the receiving province. The formula is as follows:

[0033] P a =P l -ρ w ×G w -ρ s ×G s (1)

[0034] Among them, P a Represents the net load curve of the receiving province, P l represents the unified electricity load curve of the receiving province in the previous year, G w Represents the installed capacity of wind power, G s represents the installed capacity of photovoltaic power generation, ρ w Represents the hourly output coefficient of wind power, ρ s Indicates the photovoltaic hourly output coefficient.

[0035] S2: Decompose the agreed power delivery according to the net load curve. The specific steps are as follows:

[0036] Net load curve Pa By integrating monthly and time periods, we can obtain the monthly electricity demand of the receiving provinces. The formula is as follows:

[0037]

[0038] Among them, E n It represents the monthly electricity demand of the receiving province, m represents the number of days, and n represents the month. According to the monthly electricity demand, the power supply agreement electricity is decomposed into months. The formula is as follows:

[0039]

[0040] Among them, E pro Indicates the power supply agreement quantity, E pro，n Indicates the monthly power transmission agreement electricity amount.

[0041] S3: Determine the peak and valley transmission power, duration and time distribution in the daily UHV DC transmission curve according to the net load characteristics. The specific steps are as follows:

[0042] Based on the principle of simplicity and ease of use, a two-step transmission method is used to determine the peak and valley transmission powers in the daily UHV DC transmission curve. The schematic diagram is shown in the figure. Figure 2 As shown, the formula is as follows:

[0043] (1-β)×P×t+P×(24-t)=E (4)

[0044] Among them, P is the maximum power transmission of the day. Considering the stability constraint, it does not exceed the upper limit of the designed transmission power. β is the peak-to-valley difference rate. t is the duration of low-power power transmission. E is the daily power transmission amount.

[0045] According to the above formula, the formula for the maximum power transmission on the day is as follows:

[0046]

[0047] Among them, β is obtained by analyzing the net load characteristics, and E is the monthly power transmission agreement power E pro，n Divide into daily electricity in equal proportions;

[0048] The minimum power transmission on that day is:

[0049] P0=(1-β)×P (6)

[0050] Then the time period distribution of t is optimized. Specifically, the net load characteristics are analyzed on a monthly basis, the daily average load is used as a benchmark, and the duration and time period distribution of the load distribution below this value are counted.

[0051] Here is an example:

[0052] Taking the data analysis of a certain receiving province as an example, the optimized duration is shown in Table 1, and the time period distribution is shown in Table 2.

[0053] Table 1 Monthly low-power transmission duration of UHV DC

[0054] Unit: Hours

[0055] month January February March April May June July August September October November December t 13 14 14 15 15 15 12 12 15 14 13 13

[0056] Table 2 Peak and valley period distribution of UHV DC transmission curve by month

[0057] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 January 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 1 February 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 1 0 0 0 0 0 0 1 March 1 1 1 1 1 1 1 0 0 0 1 1 1 1 1 1 0 0 0 0 0 0 0 1 April 1 1 1 1 1 1 1 0 0 0 1 1 1 1 1 1 1 0 0 0 0 0 0 1 May 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 1 June 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 1 July 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 August 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 September 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 1 October 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 November 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 1 1 December 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 1

[0058] In Table 2, "1" indicates a low-power power transmission period, and "0" indicates a high-power power transmission period.

[0059] Combining equations (3), (5) and Tables 1 and 2, the optimized UHV DC monthly transmission power curve is obtained as follows: Figure 3 As shown, in actual power transmission, the optimized monthly power transmission power is used as the standard. This method fully considers the power load curve of the receiving provinces and the new energy power generation output curve, and combines the peak-shaving demand of the power system in the whole province to propose a power transmission curve optimization method. After production simulation verification, this method can effectively alleviate the peak-shaving pressure of the receiving provinces, reduce the amount of wind and photovoltaic power abandoned in the receiving provinces, and has obvious economic benefits in reducing the receiving power grid's power purchase cost and peak-shaving auxiliary service cost.

[0060] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for optimizing UHV DC transmission curves to assist peak load regulation in receiving provinces, characterized in that: The steps include: S1: Get the net load curve of the receiving province; S2: Decompose the agreed power delivery according to the net load curve; S3: Determine the peak and valley transmission power, duration and time distribution in the UHV DC daily transmission curve based on the net load characteristics; In step S1, the formula for obtaining the net load curve of the receiving province is as follows: P a =P l -r w ×G w -r s ×G s Among them, P a represents the net load curve of the receiving province, P l represents the unified electricity load curve of the receiving province in the previous year, G w Represents the installed capacity of wind power, G s represents the installed capacity of photovoltaic power generation, ρ w Represents the hourly output coefficient of wind power, ρ s Indicates the photovoltaic hourly output coefficient; The step S2 is specifically as follows: Net load curve P a By integrating monthly and time periods, we can obtain the monthly electricity demand of the receiving provinces. The formula is as follows: Among them, E n It represents the monthly electricity demand of the receiving province, m represents the number of days, n represents the month, and t represents the duration of low-power power transmission; According to the monthly power demand, the power supply agreement power is decomposed into monthly, and the formula is as follows: Among them, E pro Indicates the power supply agreement quantity, E pro，n Indicates the monthly power transmission agreement quantity; In step S3, a two-step power transmission method is adopted when determining the peak and valley power transmission powers in the UHV DC daily power transmission curve, and the formula is as follows: (1-β)×P×t+P×(24-t)=E Among them, P is the maximum power transmission of the day. Considering the stability constraint, it does not exceed the upper limit of the designed transmission power. β is the peak-to-valley difference rate, and E is the daily power transmission amount. According to the above formula, the formula for the maximum power transmission on the day is as follows: Among them, β is obtained by analyzing the net load characteristics, and E is the monthly power transmission agreement power E pro，n Divide into daily electricity in equal proportions; The minimum power transmission on that day is: P0=(1-β)×P.

2. The method for optimizing UHV DC transmission curve for assisting peak load regulation in receiving provinces according to claim 1, characterized in that: In step S3, when determining the duration and time period distribution of the daily power transmission curve, the time period distribution of t needs to be optimized, specifically: the net load characteristics are analyzed on a monthly basis, with the daily average load as a benchmark, and the duration and time period distribution of the load distribution below this value are counted.

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