New energy integrated base outbound power transmission optimization method and optimization system

Abstract

The invention provides a new energy integrated base outbound power transmission optimization method and optimization system. The method comprises the following steps: receiving end data processing; new energy base data processing; determining an extra-high voltage direct current output electric quantity organization mode; constructing a sending-out optimization model; and determining an optimal delivery mode. From the perspective of new energy base takeout, a takeout optimization model with the highest new energy base takeout benefit and the maximum new energy utilization rate as targets is constructed, meanwhile, the receiving end net rack constraint and the landing electricity price constraint are considered, and multiple new energy base takeout scheme combinations meeting the power requirements of the transmitting end and the receiving end are formulated; strategy making is closer to actual requirements, and a theoretical reference is provided for making an optimal delivery strategy of a new energy base.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission of new energy systems, and in particular to a method and system for optimizing power transmission from a new energy integrated base. Background Art

[0002] Under the guidance of the "dual carbon" goals, provinces across the country are actively building a new power system with a gradually increasing proportion of new energy, promoting large-scale optimization of clean power resources, and continuously developing multiple clean energy bases including hydropower, wind power, photovoltaics and other power sources.

[0003] In order to achieve safe and stable power supply, various regions have gradually explored the use of ultra-high voltage direct current transmission to meet social needs. The so-called ultra-high voltage direct current transmission method has many technical advantages such as large transmission capacity, long distance, high efficiency and low loss. It has been widely used in the long-distance transmission of electricity from new energy bases across provinces to load centers.

[0004] Regarding the power transmission of new energy bases, scholars have carried out relevant research, including research on the optimal configuration of new energy base capacity, research on the optimal scheduling of new energy base output, research on multi-energy complementary scheduling of new energy bases, and research on the optimization of long-term operation modes of new energy bases.

[0005] In recent years, with the continuous implementation of government policies, clean power sources in various provinces have developed in a homogeneous manner, and the phenomenon of synchronous output of new energy in the sending and receiving provinces has become common. At present, most of the research results are based on the largest scale or lowest cost of power transmission from new energy bases to carry out research on the transmission mechanism, lacking consideration of the actual power gap and time constraints of the load in the receiving provinces, resulting in the mismatch between the comprehensive transmission curve of various types of power sources in the new energy base and the actual load demand curve of the receiving provinces, which in turn leads to difficulties in the transmission of power from the new energy base in certain periods of time, which not only affects the overall economic efficiency of the new energy base, but also aggravates the wind and solar abandonment rates of the new energy base. In addition, for the optimization and dispatching of the transmission of new energy bases, there is currently a lack of research that fully considers the grid constraints of the receiving end. Summary of the invention

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the present invention discloses a method and system for optimizing power transmission from a new energy integrated base.

[0007] The technical solution provided by the present invention is: a method for optimizing power transmission from a new energy integrated base, comprising the following steps:

[0008] According to the total load demand of the receiving province and the information of the electricity quantity organized in the province, the power demand gap of the province is calculated, the monthly electricity demand is obtained, and the typical daily demand curve of each month is generated;

[0009] Obtain the information of various types of power generation units in the sending-end new energy base, integrate the day-ahead output of various types of power sources, and generate the output curves of various types of power sources;

[0010] Couple the output curves of various types of power sources with the typical daily demand curve to form a power quantity organization that mainly consists of the power quantity of the new energy base and is supplemented by the marketized transaction power quantity;

[0011] Based on the obtained power quantity organization data, establish an optimization model under different constraint conditions;

[0012] Based on the optimization model, solve various new energy base external power quantity organizations that meet the receiving-end demand, combine the optimization objectives, compare and select the best external power transmission method of the new energy base, and formulate the optimal external power transmission strategy.

[0013] Preferably, the generation of the load demand curve specifically includes: obtaining the total annual power demand L of the receiving-end province d , the local consumption level P of the power sources in this province loc , the organized external power input P from other provinces orn , measuring the actual power gap P of the receiving-end province d , according to the monthly load demand forecast of the receiving-end province, distribute the actual power gap to each month to form a data column X = [x1, x2,..., x 12 T ;

[0014] L d = P loc + P orn + P d

[0015]

[0016] Combined with the load curves, the power output curves of the power sources available for local consumption, and the agreed curves of the organized external power input from other provinces in the receiving-end province over the years, fit the actual power demand curves E i (t) of the typical days in each month of the receiving-end:

[0017]

[0018] In the formula, D i represents the number of days in the i-th month; t represents the time.

[0019] Further preferably, the generation of the output curves of various types of power sources specifically includes:

[0020] Collect the historical hourly output panel data of wind power, photovoltaic power, thermal power, and nuclear power in the new energy base, and record the data of the d-th day in the i-th month of each as P wi , P pvi , P hi , P npi ​, predict the daily output curves of wind power, photovoltaic power, thermal power, and nuclear power, and denote the output results as P wi (t), P pvi (t), P hi (t), P npi (t):

[0021] P wi = [P w1 , P w2 ,..., P w24 → P wi (t)

[0022] P pvi = [P pv1 , P pv2 ,..., P pv24 P pvi (t)

[0023] P hi = [P h1 , P h2 ,..., P h24 → P hi (t)

[0024] P npi = [P np1 , P np2 ,..., P np24 → P npi (t) (3)

[0025] The output model of the energy storage system is:

[0026]

[0027] In the formula, SOC t , SOC t-1 are the state of charge of the energy storage at times t and t - 1, respectively; w1 and w2 are the charging efficiency and discharging efficiency of the energy storage device, respectively; P stc , P std are the charging power and discharging power of the energy storage system at time t, respectively; E sn is the rated capacity of the energy storage device; Δt is the interval time.

[0028] Further preferably, the coupling of the output curves of each type of power source and the typical daily demand curve specifically includes:

[0029] Couple the actual load demand curve of the typical day of the receiving end month with the daily output curves of each type of power source in the new energy base to meet an error of ±5%:

[0030]

[0031] In the formula, Pmoi is the electricity quantity of the typical day in the i-th month in the market-oriented organization; P r represents the electricity quantity agreed in the r-th market-oriented transaction contract in the i-th month;

[0032] According to the curve fitting results, an electricity quantity organization plan M is formed, with the electricity quantity of the new energy base as the main part and the market-oriented transaction electricity quantity as the supplement j , M j includes wind power, photovoltaic power, thermal power, nuclear power, and market-oriented organization electricity quantity, and the expression is:

[0033] M j = [wind power, photovoltaic power, thermal power, nuclear power, market-oriented organization] = [P wj , P pvj , P hj , P npj , P moj .

[0034] Further preferably, in the establishment of the optimization model, it includes the external transmission benefit R of the new energy base and the new energy utilization rate η. The calculation formula for the external transmission benefit R of the new energy base is as follows:

[0035]

[0036] In the formula, p1, p2, p3, p4, p r respectively represent the electricity prices of wind power, photovoltaic power, thermal power, nuclear power, and the r-th market-oriented transaction contract;

[0037] The calculation formula for the new energy utilization rate η is as follows:

[0038]

[0039] Further preferably, in the establishment of the optimization model, the operation constraints of the UHV DC for the new energy base to send out, the power balance constraints at the sending and receiving ends, the power output constraints of the power sources, and the grid operation constraints are considered. Among them,

[0040] The operation constraints of the UHV DC need to comprehensively consider the upper and lower limits of DC operation, the DC power continuity constraint, and the duration constraint when optimizing the external transmission method of the new energy base;

[0041] The upper and lower limits of DC operation constraint:

[0042]

[0043] In the formula, P DC min , P DC max , P DC t respectively represent the minimum power, maximum power, and actual transmission power at the t-th moment of the UHV DC operation;

[0044] DC power continuity constraint:

[0045]

[0046] where z + (t) and z － (t) represent the ramp-up and ramp-down states of the DC system respectively. Both are 0-1 variables. A value of 1 indicates occurrence, otherwise 0;

[0047] Duration constraint:

[0048]

[0049] where T is the shortest duration for the DC system to operate stably at a certain power level; s represents the time sequence number;

[0050] Power balance constraint between the sending and receiving ends:

[0051] Considering the load demand at the receiving end, the power balance constraint of the new energy base's external power transmission system is that the error between the annual load gap at the receiving end and the sum of the external power transmission from the new energy base and the market-organized power does not exceed 5%. Specifically, it can be expressed as:

[0052]

[0053] Power output constraint of power sources:

[0054] The external power transmission power sources of the new energy base include wind power, photovoltaic power, thermal power, and nuclear power. At the same time, a certain scale of regulating power source energy storage is configured. The power output of each type of power source has certain constraints;

[0055] Wind power output constraint: The output power of a wind turbine at time t is restricted by the rated power P W and has upper and lower limits;

[0056]

[0057] Photovoltaic power output constraint: The output power of a photovoltaic power generation unit at time t is restricted by the rated power P PV and has upper and lower limits;

[0058]

[0059] Thermal power output constraint: It includes output constraint and ramp constraint. Among them, the output power P of a thermal power unit at time t h t also has upper and lower limits P h min and P h max within a certain period; At the same time, the maximum upward ramp of the thermal power unit is △P h up max, Maximum downhill slope rate △P h down max ;

[0060]

[0061] Nuclear power output constraint: The output power of the nuclear power unit at time t is subject to the upper and lower limits of the unit output power P np max 、P np min constraint;

[0062]

[0063] Energy storage constraint: The state of charge of the energy storage does not exceed the rated capacity, and charging and discharging are not carried out at the same time.

[0064]

[0065] Grid operation constraint:

[0066] The node voltage does not exceed its upper and lower limits. At the same time, the transmission power at time t does not exceed the upper and lower limits of the receiving-end grid;

[0067]

[0068] In the formula, U min 、U max 、U t respectively represent the lower limit of the node voltage, the upper limit, and the node voltage at time t; P s min 、P s max respectively represent the minimum allowable power and the maximum power of the receiving-end grid.

[0069] Further preferably, in the established optimization model, the landed electricity price constraint is considered, where,

[0070]

[0071] In the formula, p5 and p6 respectively represent the transmission electricity price of the new energy base sending province and the electricity price of the UHV DC electricity volume; λ represents the line loss of the UHV DC; p l represents the coal-fired benchmark price of the receiving province.

[0072] Further preferably, in the specified optimal power transmission strategy, it includes the actual power transmission curves of various types of power sources in the new energy base, the actual demand curves of the receiving-end load, the peak-valley power and time distribution of the UHV DC power transmission, the marketized trading electricity volume, and the comprehensive landed electricity price strategy.

[0073] According to another aspect of the present invention, there is also provided an optimization system for the external power transmission of a new energy comprehensive base, including:

[0074] The receiving - end data processing unit is used to calculate the power demand gap of the province based on the total load demand of the receiving - end province and the organized electricity information in the province, obtain the monthly electricity demand, and generate the typical daily demand curves for each month, that is, the load demand curves.

[0075] The new - energy base data processing unit is used to obtain the information of various types of power generation units in the sending - end new - energy base, integrate the day - ahead output of various types of power sources, and generate the output curves of various types of power sources.

[0076] The confirmed unit for the electricity - sending organization method is used to couple the output curves of various types of power sources with the load demand curves to form an electricity organization mainly based on the electricity from the new - energy base and supplemented by market - based trading electricity.

[0077] The optimization model construction unit is used to establish an optimization model under different constraint conditions according to the obtained electricity - organization data.

[0078] The optimal power - sending method selection unit, based on the optimization model, solves various electricity - sending organizations of the new - energy base that meet the receiving - end demand in combination with the optimization goal, compares and selects to determine the best power - sending method of the new - energy base, and formulates the optimal power - sending strategy.

[0079] Preferably, in the confirmed unit for the electricity - sending organization method, with the operation constraints of the UHV DC set for the power transmission from the new - energy base, the power - balance constraints between the sending and receiving ends, the power - output constraints of the power sources, the grid - operation constraints, and the landing - price constraints as the boundaries, through various bundled power - sending combination methods of various types of power sources in the new - energy base and market - based trading electricity included in the receiving - end demand, with the optimization goals of the highest power - sending benefit of the new - energy base and the maximum utilization rate of new energy, the best power - sending method of the new - energy base is determined.

[0080] The beneficial effects of the present invention are as follows:

[0081] In the total power demand of the receiving - end province, subtract the output that can be consumed locally by the power sources in the province and the currently organized power input from other provinces to obtain the actual power gap of the receiving - end province; based on the historical - year load curves of the receiving - end province, predict the typical daily load demand curves for each month of the receiving - end province to obtain the typical daily power - gap demand curves for each month of the receiving - end, which is beneficial to improving the matching degree between the output curve of the new - energy base and the actual demand curve, and avoiding the problem of power curtailment caused by insufficient consideration of the receiving - end's acceptance capacity currently.

[0082] Couple the output curves of various types of power sources with the load demand curves, measure multiple bundled power - sending combinations of various types of power sources in the new - energy base that meet the receiving - end demand within the allowable deviation range, and form an electricity - organization method mainly based on the electricity from the new - energy base and supplemented by market - based trading electricity, providing multiple options for the power transmission from the new - energy base.

[0083] From the perspective of power transmission from new energy bases, considering both the power transmission benefits and the utilization rate of new energy in new energy bases, an optimization objective function for power transmission from new energy bases is constructed to avoid sacrificing the utilization rate of new energy by only pursuing the maximum power transmission volume or the highest economy;

[0084] The constraints of the receiving-end grid and the constraint that the landing electricity price does not exceed the coal-fired benchmark price of the receiving province are considered within the constraints of the optimization model, providing a new idea for constructing the optimization model;

[0085] Compared with traditional research, based on the actual power gap in the receiving province, the present invention fully fits the daily demand curve with the output curves of various types of power sources in the new energy base, and calculates multiple bundled power transmission combinations of various types of power sources in the new energy base that meet the demand of the receiving end, forming a power organization plan mainly based on the electricity volume of the new energy base supplemented by marketized transaction electricity volume, which can effectively solve the problem of difficult power transmission from the new energy base in some periods caused by the homogeneous development of power sources at the sending and receiving ends. Different from the traditional research carried out from the perspective of the largest power transmission scale or the lowest cost of the new energy base, from the perspective of power transmission from the new energy base, an external power transmission optimization model with the highest external power transmission benefit and the largest utilization rate of new energy as the goal is constructed. At the same time, the constraints of the receiving-end grid and the landing electricity price are considered, and multiple external power transmission plan combinations that meet the power demand at the sending and receiving ends are formulated, making the strategy formulation closer to the actual requirements and providing a theoretical reference for formulating the optimal external power transmission strategy of the new energy base. Description of the Drawings

[0086] Figure 1 It is a flowchart of an external power transmission optimization method for a new energy comprehensive base provided by the present invention;

[0087] Figure 2 It is a schematic diagram of external power transmission of a new energy base in an external power transmission optimization method for a new energy comprehensive base provided by the present invention. Detailed Embodiments

[0088] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0089] The present invention provides an external power transmission optimization method for a new energy comprehensive base. Referring to Figure 1 as shown, it includes the following steps:

[0090] Receiving-end data processing: According to the total load demand of the receiving province and the information of the electricity volume already organized in the province, calculate the power demand gap of the province to obtain the monthly electricity demand, and generate the typical daily demand curves for each month, that is, the load demand curves;

[0091] Obtain the total annual power demand L of the receiving provinced , the power supply in this province can support the local consumption level P loc , the power imported from other provinces that has been organized is P orn , measure the actual power gap P in the receiving province d , according to the monthly load demand forecast of the receiving province, allocate the actual power gap to each month to form a data column X = [x1, x2, …, x 12 T ;

[0092] L d = P loc + P orn + P d

[0093]

[0094] Combined with the 8760 load curve of the receiving province over the years, the power output curve of the power supply that can be locally consumed, and the agreed curve of the power imported from other provinces that has been organized, fit the actual power demand curve E i (t);

[0095]

[0096] In the formula, D i represents the number of days in the i-th month; t represents the time;

[0097] New energy base data processing: Obtain the information of various types of power generation units in the sending-end new energy base, evaluate the day-ahead output of various types of power sources, and generate an output curve;

[0098] Collect the historical hourly output panel data of wind power, photovoltaic power, thermal power, and nuclear power in the new energy base. Denote the data on the d-th day of the i-th month of each as P wi , P pvi , P hi , P npi , predict the day-ahead output curves of wind power, photovoltaic power, thermal power, and nuclear power, and denote the output results as P wi (t), P pvi (t), P hi (t), P npi (t);

[0099] P wi = [P w1 , P w2 ,..., P w24 → P wi (t)

[0100] P pvi = [P pv1 , P pv2 ,..., P pv24 → P​pvi (t)

[0101] P hi =[P h1 ,P h2 ,...,P h24 →P hi (t)

[0102] P npi =[P np1 ,P np2 ,...,P np24 →P npi (t) (3)

[0103] The volatility and randomness of wind power and photovoltaic power generation increase the difficulty of power transmission from new energy bases. Although thermal power can play a part in providing backup support, due to the limitation of new energy utilization rate, the configuration ratio of thermal power is restricted to a certain scale. A certain scale of energy storage resources needs to be configured in new energy bases, which is required to have the potential to participate in smoothing the output curve to effectively improve the system regulation flexibility of new energy bases. The output model of the energy storage system is as follows:

[0104]

[0105] In the formula, SOC t 、SOC t-1 are the state of charge of the energy storage at times t and t - 1 respectively; w1 and w2 are the charging efficiency and discharging efficiency of the energy storage device respectively; P stc 、P std are the charging power and discharging power of the energy storage system at time t respectively; E sn is the rated capacity of the energy storage device; △t is the interval time;

[0106] Determine the organization method of the transmitted power of UHV DC: Couple the output curves of various types of power sources with the load demand curve, and determine the bundled external transmission combinations of various types of power sources from multiple new energy bases that meet the demand of the receiving end within the allowable deviation range, forming a power organization mainly based on the power of new energy bases supplemented by market transaction power;

[0107] Couple the actual load demand curve of the typical day in a month at the receiving end with the day-ahead output curves of various types of power sources in the new energy base, meeting an error of ±5%;

[0108]

[0109] In the formula, P moi is the market-organized power of the typical day in the i-th month; P r represents the power agreed in the r-th market transaction contract in the i-th month;

[0110] According to the curve fitting results, calculate the bundled external transmission combinations of various types of power sources in multiple new energy bases that meet the receiving-end demand, and form a power quantity organization plan M with the power quantity of new energy bases as the main part and the marketized transaction power quantity as the supplement. j , including wind power, photovoltaic power, thermal power, nuclear power, and marketized organized power quantity, which is expressed as:

[0111] M j = [wind power, photovoltaic power, thermal power, nuclear power, marketized organization] = [P wj , P pvj , P hj , P npj , P moj ;

[0112] Build an external transmission optimization model: aiming at the highest external transmission benefit of the new energy base and the maximum utilization rate of new energy, taking into account the operating constraints of UHV DC, the power balance constraints between the sending and receiving ends, the power output constraints of power sources, the grid operation constraints, and the landing electricity price constraints, and establish an optimization model. Among them,

[0113] The external transmission benefit R of the new energy base and the utilization rate η of new energy. The calculation formula for the external transmission benefit R of the new energy base is as follows:

[0114]

[0115] In the formula, p1, p2, p3, p4, p r respectively represent the electricity prices of wind power, photovoltaic power, thermal power, nuclear power, and the rth marketized transaction contract;

[0116] The calculation formula for the utilization rate η of new energy is as follows:

[0117]

[0118] If the optimization goal is to be achieved, it is also necessary to consider the operating constraints of the UHV DC for the new energy base to send out, the power balance constraints between the sending and receiving ends, the power output constraints of power sources, and the grid operation constraints;

[0119] Inter-provincial and inter-regional UHV DC transmission is an optimal path to realize the optimal allocation of assets on a national scale. According to the actual operating characteristics of UHV DC transmission lines, the upper and lower limits of DC operation, the DC power continuity constraint, and the duration constraint that need to be comprehensively considered when optimizing the external transmission mode of new energy bases;

[0120] Upper and lower limits of DC operation constraint:

[0121]

[0122] In the formula, P DC min , P DC max , PDC t respectively represent the minimum power, maximum power of UHV DC operation, and the actual transmission power at time t;

[0123] DC power continuity constraint:

[0124]

[0125] In the formula, z + (t) and z － (t) respectively represent the climbing and sliding states of the DC system. Both are 0-1 variables. When it occurs, it is recorded as 1, otherwise it is recorded as 0;

[0126] Duration constraint:

[0127]

[0128] In the formula, T is the shortest duration for the DC to operate stably at a certain power level; s represents the time sequence number;

[0129] Power balance constraint between the sending and receiving ends:

[0130] The power balance constraint of the new energy base external power transmission system considering the receiving end load demand is that the error between the annual load gap at the receiving end and the sum of the external power transmission electricity of the new energy base and the marketized organized electricity does not exceed 5%. Specifically, it can be expressed as:

[0131]

[0132] Power output constraint of power sources:

[0133] The external power transmission power sources of the new energy base include wind power, photovoltaic power, thermal power, and nuclear power. At the same time, a certain scale of regulating power source energy storage is configured. There are certain constraints on the power output of each type of power source;

[0134] Wind power output constraint: The output power of the wind turbine at time t is limited by the rated power P W and has upper and lower limits;

[0135]

[0136] Photovoltaic power output constraint: The output power of the photovoltaic power generation unit at time t is limited by the rated power P PV and has upper and lower limits;

[0137]

[0138] Thermal power output constraint: It includes output constraint and climbing constraint. Among them, the output power P of the thermal power unit at time t h t also has upper and lower limits P h min 、Ph max ; Meanwhile, there is a maximum upward ramp rate △P for thermal power units during ramping h up max and a maximum downward ramp rate △P h down max ;

[0139]

[0140] Nuclear power output constraint: The output power of a nuclear power unit at time t is subject to the upper and lower limits of the unit's output power P np max and P np min .

[0141]

[0142] Energy storage constraint: The state of charge of the energy storage does not exceed the rated capacity, and charging and discharging are not carried out at the same time.

[0143]

[0144] Grid operation constraint:

[0145] The operation constraints of the receiving-end grid should be considered in the formulation of the new energy base power transmission strategy. To ensure the safe and stable operation of the system, it is required that the node voltage does not exceed the limit, that is, the node voltage does not exceed its upper and lower limits. At the same time, the transmission power at time t does not exceed the upper and lower limits of the receiving-end grid;

[0146]

[0147] In the formula, U min and U max and U t respectively represent the lower limit of the node voltage, the upper limit, and the node voltage at time t; Psmin and Psmax respectively represent the minimum allowable power and the maximum power of the receiving-end grid;

[0148] Taking the highest power transmission benefit of the new energy base as one of the optimization objectives, but the comprehensive landing electricity price shall not be higher than the benchmark on-grid electricity price of the sending-end province, otherwise it will lose market competitiveness;

[0149]

[0150] In the formula, p5 and p6 respectively represent the transmission price of the new energy base sending province and the electricity price of the UHV DC; λ represents the line loss of the UHV DC; pl represents the coal-fired benchmark price of the receiving-end province;

[0151] Based on the optimization model, solve for various combinations of new energy base power transmission quantities that meet the receiving-end demand, combined with the optimization objectives, compare and select to determine the best power transmission method of the new energy base, and formulate the optimal power transmission strategy;

[0152] Input the daily output curves of various types of power sources in the new energy base power transmission system and the actual power demand curves of typical days in each month at the receiving end. Taking the UHV DC operation constraints, power balance constraints between the sending and receiving ends, power output constraints of power sources, grid operation constraints, and landing electricity price constraints set for the power transmission of the new energy base as the boundaries, solve various bundled power transmission combinations that meet the receiving end demand and include various types of power sources in the new energy base and marketized transaction electricity. Combining the optimization goals of the highest power transmission benefit of the new energy base and the maximum utilization rate of new energy, compare and select to determine the best power transmission method for the new energy base, including the actual power transmission curves of various types of power sources in the new energy base, the actual demand curves of the receiving end load, the peak-valley power and time period distribution of UHV DC power transmission, marketized transaction electricity, and comprehensive landing electricity price strategy.

[0153] On the other hand, the present invention also provides an optimization system for power transmission from a comprehensive new energy base, including

[0154] A receiving end data processing unit, which is used to calculate the power demand gap of the province according to the total load demand of the receiving end province and the organized electricity information of the province, obtain the monthly electricity demand, and generate the demand curves of typical days in each month;

[0155] A new energy base data processing unit, which is used to obtain the information of various types of power source units in the sending end new energy base, integrate the daily output of various types of power sources, and generate the output curves of various types of power sources;

[0156] A power transmission quantity organization method confirmation unit, taking the UHV DC operation constraints, power balance constraints between the sending and receiving ends, power output constraints of power sources, grid operation constraints, and landing electricity price constraints set for the power transmission of the new energy base as the boundaries, through various bundled power transmission combination methods that meet the receiving end demand and include various types of power sources in the new energy base and marketized transaction electricity, with the optimization goals of the highest power transmission benefit of the new energy base and the maximum utilization rate of new energy, determine the best power transmission method for the new energy base.

[0157] An optimization model construction unit, which is used to establish an optimization model under different constraint conditions according to the obtained power transmission quantity organization data;

[0158] An optimal power transmission method selection unit, based on the optimization model to solve various power transmission quantity organizations of the new energy base that meet the receiving end demand and combine the optimization goals, compare and select to determine the best power transmission method for the new energy base, and formulate the optimal power transmission strategy.

[0159] It should be understood that those skilled in the art, inspired by the technical concept of the present invention and without departing from the content of the present invention, can make various improvements and transformations according to the above description, and this still falls within the protection scope of the present invention.

[0160] Other embodiments of the present invention will be readily apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include known common general knowledge or conventional technical means in the technical field not disclosed in the present invention. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the invention are pointed out by the claims.

[0161] It should be understood that the present invention is not limited to the exact structures shown in the above description and can be modified and changed without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. An optimization method for power transmission outside a new energy comprehensive base, characterized in that It includes the following steps: According to the total load demand of the receiving province and the organized electricity quantity information of the province itself, calculate the electricity demand gap of the province itself, obtain the monthly electricity demand, and generate the typical daily demand curves for each month; Obtain the information of each type of power generation unit in the sending-end new energy base, integrate the day-ahead output of each type of power source, and generate the output curves of each type of power source; Couple the output curves of each type of power source with the typical daily demand curves to form an electricity organization mainly based on the electricity quantity of the new energy base and supplemented by marketized trading electricity quantity; According to the obtained electricity organization data, establish an optimization model under different constraint conditions; Based on the optimization model, solve various electricity organization combinations for the new energy base to meet the receiving-end demand, combine the optimization objectives, compare and select the best external transmission method of the new energy base, and formulate the optimal external transmission strategy.

2. The optimized method for transmitting electricity outside a new energy comprehensive base according to claim 1, wherein The generation of the load demand curve specifically includes: obtaining the total annual power demand L of the receiving province d , the level P of the local power supply that can be consumed locally in this province loc , the power P already organized for input from other provinces orn , measuring the actual power gap P of the receiving province d , according to the monthly load demand forecast of the receiving province, distributing the actual power gap to each month to form a data column X = [x1, x2,..., x 12 T ;​ L d = P loc + P orn + P d Combined with the load curves of the receiving provinces over the years, the power output curves of the power sources that can be locally consumed, and the agreed curves of the organized power input from other provinces, the actual power demand curve E i (t): where D i represents the number of days in the i-th month; t represents the time.

3. The optimized method for power transmission outside a new energy comprehensive base according to claim 1, wherein The specific process of generating the output curves of each type of power source includes: Collect the historical hourly output panel data of wind power, photovoltaic power, thermal power, and nuclear power in the new energy base, and denote the data of the i-th month and the d-th day of each as P wi 、P pvi 、P hi 、P npi . Predict the daily output curves of wind power, photovoltaic power, thermal power, and nuclear power, and denote the output results as P wi (t), P pvi (t), P hi (t), P npi (t): P wi = [P w1 , P w2 ,..., P w24 → P wi (t) P pvi = [P pv1 , P pv2 ,..., P pv24 → P pvi (t) P hi = [P h1 , P h2 ,..., P h24 → P hi (t) P npi = [P np1 , P np2 ,..., P np24 → P npi (t) (3) The output model of the energy storage system is: Where, SOC t and SOC t-1 are the state of charge of the energy storage at times t and t-1 respectively; w1 and w2 are the charging efficiency and discharging efficiency of the energy storage device respectively; P stc and P std are the charging power and discharging power of the energy storage system at time t respectively; E sn is the rated capacity of the energy storage device; Δt is the interval time.

4. A method for optimizing the external power transmission of a new energy comprehensive base according to claim 1, characterized in that, The specific process of coupling the output curves of each type of power source with the typical daily demand curves includes: Couple the actual load demand curve of the monthly typical day at the receiving end with the day-ahead output curves of each type of power source in the new energy base to meet an error of ±5%; Where P moi is the electricity quantity of the typical day in the i-th month in the market-oriented organization; P r represents the electricity quantity agreed in the r-th market-oriented transaction contract in the i-th month. According to the curve fitting results, an electricity organization plan M is formed, which is mainly based on the electricity quantity of the new energy base and supplemented by the electricity quantity of market-based transactions j , M j including wind power, photovoltaic power, thermal power, nuclear power, and market-based organized electricity quantity, and the expression is as follows: M j = [Wind power, Photovoltaic, Thermal power, Nuclear power, Market-based organization] = [P wj , P pvj , P hj , P npj , P moj .

5. The optimization method for power transmission outside a new energy comprehensive base according to claim 1, wherein In the establishment of the optimization model, it includes the external transmission benefit R of the new energy base and the new energy utilization rate η. The calculation formula for the external transmission benefit R of the new energy base is as follows: where p1, p2, p3, p4, p r represent the electricity prices of wind power, photovoltaic power, thermal power, nuclear power, and the r-th market transaction contract respectively; The calculation formula for the new energy utilization rate η is as follows:

6. The optimization method for power transmission outside a new energy comprehensive base according to claim 1, wherein In the establishment of the optimization model, consider the operation constraints of the UHV DC for the new energy base to send out power, the power balance constraints between the sending and receiving ends, the power output constraints of the power sources, and the grid operation constraints. Among them, The operation constraints of the UHV DC need to comprehensively consider the upper and lower limits of DC operation, the continuity constraint of DC power, and the duration constraint when optimizing the external transmission method of the new energy base; The upper and lower limits of DC operation: Wherein, P DC min , P DC max , P DC t respectively represent the minimum power, the maximum power, and the actual transmitted power at time t during the operation of UHVDC; The continuity constraint of DC power: where z + (t) and z － (t) represent the ramping up and ramping down states of the DC system respectively, both of which are 0-1 variables. A value of 1 indicates an occurrence, and 0 otherwise; The duration constraint: In the formula, T is the shortest continuous operation duration of the DC at a certain power level; s represents the time serial number; The power balance constraint between the sending and receiving ends: The power balance constraint of the external transmission system of the new energy base considering the receiving-end load demand is manifested as the error between the annual load gap at the receiving end and the sum of the electricity quantity sent out by the new energy base and the marketized organized electricity quantity not exceeding 5%. Specifically, it can be manifested as: The power output constraint of the power source: The power sources for the new energy base to send out power include wind power, photovoltaic power, thermal power, and nuclear power. At the same time, a certain scale of regulating power source energy storage is configured, and there are certain constraints on the power output of each type of power source; Wind power output constraint: The output power of the wind turbine at time t is limited by the rated power P W and has upper and lower limits; Photovoltaic output constraint: The output power of the photovoltaic power generation unit at time t is limited by the rated power P PV and has upper and lower limits; Thermal power output constraint: including output constraint and ramping constraint. Among them, the output power P of the thermal power unit at time t h t also has upper and lower limits P within a certain period h min , P h max ; At the same time, there is a maximum upward ramp △P for the ramping of the thermal power unit h up max , and a maximum downward ramp rate △P h down max ; Nuclear power output constraint: The output power of the nuclear power unit at time t is subject to the upper and lower limits of the unit's output power P np max 、P np min constraints; The energy storage constraint: The state of charge of the energy storage does not exceed the rated capacity, and charging and discharging are not carried out at the same time; The grid operation constraint: The node voltage does not exceed its upper and lower limits. At the same time, the transmission power at time t does not exceed the upper and lower limits of the receiving-end grid; Wherein, U min , U max , U t respectively represent the lower limit of the node voltage, the upper limit of the node voltage, and the node voltage at time t; P s min , P s max respectively represent the minimum allowable power and the maximum power of the receiving-end grid.

7. A method for optimizing the external power transmission of a new energy comprehensive base according to claim 1, characterized in that, In the establishment of the optimization model, consider the landing electricity price constraint. Among them, Wherein, p5 and p6 respectively represent the transmission price of the new energy base in the power transmission province and the electricity price of the UHV DC; λ represents the line loss of the UHV DC; p l represents the benchmark coal price of the receiving province.

8. A method for optimizing the external power transmission of a new energy comprehensive base according to claim 1, characterized in that, In the formulation of the optimal external transmission strategy, it includes the actual external transmission curves of each type of power source in the new energy base, the actual load demand curve at the receiving end, the peak-valley power and time period distribution of the UHV DC external transmission, the marketized trading electricity quantity, and the comprehensive landing electricity price strategy.

9. An optimized system for power transmission outside a new energy comprehensive base, characterized in that It includes: The receiving-end data processing unit is used to calculate the electricity demand gap of the receiving-end province itself according to the total load demand of the receiving-end province and the organized electricity quantity information of the province itself, obtain the monthly electricity demand, and generate the typical daily demand curves for each month; A data processing unit for a new energy base, which is used to obtain information on various types of power generation units in the sending-end new energy base, integrate the daily output of various types of power sources, and generate output curves for various types of power sources; A unit for confirming the organization method of the sent-out electricity quantity, which is used to couple the typical daily demand curves of the output of various types of power sources to form an electricity quantity organization mainly based on the electricity quantity of the new energy base and supplemented by the marketized transaction electricity quantity; An optimization model construction unit, which is used to establish an optimization model under different constraint conditions according to the obtained electricity quantity organization data; An optimal external transmission method selection unit, based on the optimization model, solves various external transmission electricity quantity organizations of the new energy base that meet the receiving-end demand, combines the optimization objectives, compares and selects to determine the best external transmission method of the new energy base, and formulates an optimal external transmission strategy.

10. An optimized system for transmitting power outside a new energy comprehensive base according to claim 9, characterized in that, In the unit for confirming the organization method of the sent-out electricity quantity, with the operation constraints of the UHV DC set for the external transmission of the new energy base electricity, the power balance constraints between the sending and receiving ends, the power output constraints of the power sources, the grid operation constraints, and the landing electricity price constraints as the boundaries, through various bundling external transmission combination methods of the receiving-end demand including various types of power sources and marketized transaction electricity quantities of the new energy base, with the optimization objectives of the highest external transmission benefit of the new energy base and the maximum utilization rate of the new energy, determine the best external transmission method of the new energy base.

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