A grid-province joint dispatching method and system based on grid-province equivalence

Abstract

The application provides a grid-province joint dispatching method based on grid-province equivalence, and the method comprises the following steps: establishing optimal generation scheduling sequences of each grid-province; establishing equivalence models of each grid-province based on the optimal generation scheduling sequences of each grid-province; jointly dispatching grid-province generation scheduling based on the equivalence models of each grid-province, obtaining inter-province tie-line scheduling and generation scheduling of the equivalence models of each grid-province; and establishing actual generation scheduling of each grid-province based on the generation scheduling of the equivalence models of each grid-province and the optimal generation scheduling of each grid-province, so as to realize grid-province joint dispatching based on grid-province equivalence. The application improves the operation efficiency of the multi-province interconnected power grid.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power systems, and particularly relates to a grid-province joint dispatching method and system based on province grid equivalence. BACKGROUND

[0002] There are two difficulties in the grid-province joint dispatching of multiple interconnected province grids.

[0003] On the one hand, in the power system of multiple interconnected province grids, the grid-province joint dispatching generally needs detailed information of all province grids, including information of generator units of each province grid, overload conditions of internal lines of the province grid, and the like, and then the total power generation cost of the whole grid is taken as an optimization target for power generation dispatching. However, in actual operation, each province grid has its own independent power dispatching center, and the power elements in the province are directly controlled by the provincial dispatching center rather than the grid dispatching center, and meanwhile, some of the units, loads and section information in the province are private information, so the grid dispatching center cannot know the detailed model information of the whole grid, which brings difficulties to the grid-province joint dispatching.

[0004] On the other hand, with large-scale grid connection of wind power, the uncertainty of the operation state of the province grid is enhanced, and in order to balance the power deviation caused by wind power fluctuation in a short time, if the dispatching plan is adjusted by relying on the complete grid-province model, due to the large calculation scale, it cannot be quickly and effectively solved, thereby reducing the operation efficiency of the multiple interconnected province grid power system.

[0005] Therefore, for the power system of multiple interconnected province grids, it is still a big problem to quickly and effectively implement the grid-province joint dispatching under the premise of ensuring the independent operation of each province grid.

[0006] Therefore, it is necessary to design a grid-province joint dispatching method and system based on province grid equivalence to solve the above technical problems. SUMMARY

[0007] In view of the above problems, the application provides a grid-province joint dispatching method based on province grid equivalence, wherein the method comprises:

[0008] establishing an optimal power generation plan sequence of each province grid;

[0009] establishing an equivalence model of each province grid based on the optimal power generation plan sequence of each province grid;

[0010] jointly dispatching the power generation plan of the grid-province based on the equivalence model of each province grid, to obtain the power generation plan of the equivalence model of each province grid and the inter-province tie line plan;

[0011] establishing an actual power generation plan of each province grid based on the power generation plan of the equivalence model of each province grid and the optimal power generation plan of each province grid, to realize the grid-province joint dispatching based on the equivalence of the province grid.

[0012] Further, the establishing of the optimal generation plan sequence of each provincial grid comprises:

[0013] calculating the minimum and maximum generation capacities of each provincial grid to establish a load level sequence that each provincial grid generator can undertake;

[0014] obtaining the optimal generation plan of each provincial grid under different load levels based on the load level sequence that each provincial grid generator can undertake.

[0015] Further, the calculating of the minimum and maximum generation capacities of each provincial grid comprises:

[0016] the minimum and maximum generation capacities of each provincial grid are calculated in sequence by the following expressions (1) and (2) respectively:

[0017]

[0018]

[0019] wherein, N a represents the number of generators of the a-th provincial grid, A represents the number of provincial grids, a represents the number of the provincial grid, i represents the number of the generator in the provincial grid, and are the maximum and minimum generation capacities of the a-th provincial grid in sequence respectively, and are the maximum and minimum technical output of the i-th unit in the a-th provincial grid in sequence respectively, represents "arbitrary".

[0020] Further, the establishing of the load level sequence that each provincial grid generator can undertake comprises:

[0021] the load level sequence that each provincial grid generator can undertake is established by the following expressions (3)-(6):

[0022]

[0023]

[0024]

[0025]

[0026] wherein, L a is the load level sequence of the a-th provincial grid, m is the number of elements in the load level sequence, represents the values arranged in ascending order in the load level sequence, the minimum value is equal to the minimum generation capacity of the a-th provincial grid the maximum value The maximum power generation capacity of the a-th provincial network The m-th element in the sequence M is the number of elements in the load level sequence, which is a value specified in advance. When the number of generator units in the provincial network is small, M can take a first threshold value, and when the number of generator units in the provincial network is large, M can take a second threshold value, A is "arbitrary", and A represents the number of provincial networks.

[0027] Further, the obtaining of the optimal generation plan of each province under different load levels comprises:

[0028] establishing a target function of the provincial optimization scheduling;

[0029] establishing a constraint condition of the provincial optimization scheduling;

[0030] obtaining the optimal generation plan of each province under different load levels according to the target function and the constraint condition.

[0031] Further,

[0032] The establishing of the target function of the provincial optimization scheduling comprises establishing the target function of the provincial optimization scheduling by the following expression (7):

[0033]

[0034] wherein, α a,i , β a,i , and γ a,i are, in turn, the quadratic term coefficient, the linear term coefficient, and the constant term of the fuel cost of the i-th thermal power generator unit in the a-th provincial network, respectively, c a,m represents the minimum fuel cost of the a-th provincial network when the load level is , and p a,i,m represents the optimal generation plan of the i-th thermal power generator unit in the a-th provincial network when the load level is .

[0035] Further, the establishing of the constraint condition of the provincial optimization scheduling comprises:

[0036] 1) establishing a provincial network power balance constraint, as shown in the following expression (8):

[0037]

[0038] wherein, N a represents the number of generator units in the a-th provincial network, represents the m-th element in the load level sequence of the a-th provincial network, i.e., the load size of the a-th provincial network at this time is p a,i,m represents the optimal generation plan of the i-th thermal power generator unit in the a-th provincial network when the load level is optimal generation schedule at the time t;

[0039] 2) establishing minimum and maximum technical output constraints of the provincial grid generator units, as shown in the following expression (9):

[0040]

[0041] wherein, and p a,i respectively represent the maximum and minimum technical output of the i-th unit in the a-th provincial grid, is expressed as "arbitrary";

[0042] 3) establishing upper and lower limits of transmission power of the provincial grid transmission lines, as shown in the following expression (10):

[0043]

[0044] wherein, PL a,l represents the upper limit of active power on the l-th line in the a-th provincial grid, G l,a,i represents the transfer distribution factor of the active power of the i-th thermal power generator unit on the l-th line in the a-th provincial grid, represents the load level in the a-th provincial grid, and represents the transmission power generated on the l-th line.

[0045] Further, the optimal generation schedule of all provincial grids at different load levels is obtained, including:

[0046] for all provincial grids, i.e. when m takes 1 to M, the expression (7)-(10) is solved to obtain the optimal generation schedule p a,i,m (m=1, 2,..., M) at the load level , m is the number of elements in the load level sequence, M is the number of elements in the load level sequence, and is a value specified in advance.

[0047] Further, the equivalent model of each provincial grid is established, including:

[0048] establishing an equivalent cost function model of each provincial grid;

[0049] establishing an equivalent ramp function model of each provincial grid;

[0050] establishing an equivalent inter-provincial tie-line power function model of each provincial grid.

[0051] Further, the equivalent cost function model of each provincial grid is established, including:

[0052] Using the least squares method, a piecewise quadratic function is fitted to the points in the following set to obtain the equivalent cost function model for the a-th provincial network:

[0053]

[0054] in, This indicates that the load level of the a-th provincial grid is... The total power output at any given time is expressed as in expression (14):

[0055]

[0056] Among them, c a,m (m=1,2,...,M) represents the load level of the a-th provincial grid. The minimum fuel cost at that time, of which, Let m be the m-th element of the load level sequence of the a-th provincial grid, that is, the load size of the a-th provincial grid at this time is... Let the fitted equivalent cost function model of the a-th provincial network be denoted as CT. a m is the element number in the load level sequence, M is the number of elements in the load level sequence (a pre-specified value), and A represents the number of provincial grids. It is represented as "any".

[0057] Furthermore, the establishment of the equivalent climbing function model for each provincial network includes:

[0058] Using the least squares method, a piecewise linear function is fitted to the points in the following set to obtain the equivalent upward climbing function model for the a-th provincial network:

[0059]

[0060] Among them, RU a,m (m=1,2,...,M) represents the total power output of the a-th provincial grid. RU's ability to climb hills at that time a,m The expression (16) is as follows:

[0061]

[0062]

[0063] in, This indicates that the i-th generating unit in the a-th provincial grid has a power output of p. a,i,m The maximum uphill range at time, p a,i,m This indicates that the i-th thermal power unit in the a-th provincial power grid is at a load level of The optimal power generation plan at that time the mth element of the load level sequence of the ath provincial grid, i.e. the load size of the ath provincial grid at this time the minimum technical output of the ith unit in the ath provincial grid, the upward ramping capability of the ith unit in the ath provincial grid per unit time, ΔT represents the scheduling time interval when the provincial grids are jointly scheduled, and the equivalent upward ramping function model of the ath provincial grid obtained by fitting is denoted as RU a ;

[0064] The least square method is used to fit the points in the following set by using a piecewise linear function to obtain the equivalent downward ramping function model of the ath provincial grid:

[0065]

[0066] wherein RD a,m (m = 1, 2,..., M) represents the downward ramping capability of the ath provincial grid when the power generation output is as shown in the following expression (19):

[0067]

[0068]

[0069] wherein, represents the maximum downward ramping range of the ith unit in the ath provincial grid when the power generation output of the ith unit is p a,i,m ; represents the downward ramping capability of the ith unit in the ath provincial grid per unit time; the equivalent downward ramping function model of the ath provincial grid obtained by fitting is denoted as RD a , p a,i the minimum technical output of the ith unit in the ath provincial grid, m is the number of elements in the load level sequence, M is the number of elements in the load level sequence, and A is a value specified in advance, and A represents the number of provincial grids.

[0070] Further, the establishment of the equivalent inter-provincial tie-line power function model of each provincial grid comprises:

[0071] The least square method is used to fit the points in the following set by using a piecewise linear function to obtain the equivalent inter-provincial tie-line power function model of the ath provincial grid for the φth (φ = 1, 2,..., Φ) inter-provincial tie-line:

[0072]

[0073] wherein φ represents the number of inter-provincial tie-lines, Φ represents the number of inter-provincial tie-lines, the downward ramping capability of the ath provincial grid when the power generation output is The power of the φth inter-provincial tie line is expressed as formula (22) as follows:

[0074]

[0075] wherein G φ,a,i represents the transfer distribution factor of the φth inter-provincial tie line to the active power output of the ith thermal power unit in the ath provincial grid, and the value of the transfer distribution factor can be obtained from the dispatch center of the grid dispatching, and the equivalent inter-provincial tie line power function of the ath provincial grid to the φth (φ = 1, 2,..., Φ) inter-provincial tie line obtained by fitting is denoted as H a,φ a,i,m represents the optimal generation plan of the ith thermal power unit in the ath provincial grid at the load level , m is the number of elements in the load level sequence, M is the number of elements in the load level sequence, and p

[0076] Further, the generation plan of the equivalent model of each provincial grid and the inter-provincial tie line plan is obtained by:

[0077] establishing a target function of the grid-provincial generation plan joint dispatch based on the equivalent model of the provincial grid;

[0078] establishing a constraint condition of the grid-provincial generation plan joint dispatch based on the equivalent model of the provincial grid;

[0079] obtaining the generation plan of the equivalent model of each provincial grid and the inter-provincial tie line plan based on the target function of the grid-provincial generation plan joint dispatch and the constraint condition of the grid-provincial generation plan joint dispatch.

[0080] Further,

[0081] the target function of the grid-provincial generation plan joint dispatch is established based on the equivalent model of the provincial grid, and the expression (23) is as follows:

[0082]

[0083] wherein t represents the number of dispatching periods, T represents the number of dispatching periods, CT a represents the equivalent cost function model of the ath provincial grid, and is a piecewise quadratic function of the total generation output of the ath provincial grid, Q a,t is the total generation output of the ath provincial grid in the tth dispatching period.

[0084] Further, the constraint condition of the grid-provincial generation plan joint dispatch is established based on the equivalent model of the provincial grid, and includes:

[0085] 1) the power balance constraint of the grid-provincial joint dispatch is established, and the expression (24) is as follows:

[0086] ​

[0087] wherein, Wa,t represents the total wind power output of the a-th provincial grid at the dispatching time t, S a,t represents the total load power of the a-th provincial grid at the dispatching time t, T represents the number of dispatching time periods, Q a,t is the total power generation output of the a-th provincial grid in the t-th dispatching time period;

[0088] 2) Establish the upper and lower limit constraints of the equivalent model of each provincial grid, and the expression (25) is as follows:

[0089]

[0090] wherein, and are the maximum and minimum power generation capacity of the a-th provincial grid, respectively;

[0091] 3) Establish the ramping constraint of the equivalent model of each provincial grid, and the expression (26) is as follows:

[0092] -RD a (Q a,t )≤Q a,t+1 -Q a,t ≤RU a (Q a,t ), t = 1, 2,..., T-1 (26)

[0094] wherein, RU a and RD a are the equivalent upward and downward ramping function models of the a-th provincial grid established in sequence, respectively;

[0095] 4) Establish the reserve constraint of the joint dispatching of the grid and the province, and the expression is as follows:

[0096]

[0097]

[0098] wherein, PU a,t and PD a,t are the upward and downward reserve quantities provided by the a-th provincial grid at the dispatching time t, respectively, and are the minimum upward and downward reserve quantities required by the whole grid at the dispatching time t, respectively, and A represents the number of provincial grids;

[0099] 5) Establish the inter-provincial tie-line power constraint of the joint dispatching of the provincial grid, and the expression (29) is as follows:

[0100]

[0101] Among them, PH φ H represents the upper limit of active power of the φth inter-provincial connecting line. a,φ HW represents the equivalent inter-provincial tie-line power function of the a-th provincial network to the φ-th inter-provincial tie-line. a,φ and HD a,φ The total wind power W in the a-th provincial grid is represented by the following symbols respectively. a,t and total load power S a,t The power transmitted on the φth inter-provincial connecting line.

[0102] Furthermore, the power generation plans for inter-provincial power transmission lines and equivalent models of each provincial grid are solved, including:

[0103] The branch-and-bound method is used to solve the objective function and constraints of the joint scheduling of power generation plans of the grid and provinces, resulting in the planned total power output of the a-th province at time t as Q. a,t The inter-provincial connecting line φ is planned as TL at time t. t .

[0104] Furthermore, the power generation plan based on the provincial grid equivalent model and the optimal power generation plan of each provincial grid are used to obtain the actual power generation plan of each provincial grid, including:

[0105] The provincial power grid a (a = 1, 2, ..., A) generates electricity at time t according to the equivalent model of the provincial power grid, i.e., Q. a,t Retrieve the established load level sequence and find the elements in the load level sequence that correspond to Q. a,t The closest value is denoted as Then, retrieve the established optimal power generation plan sequence and find the one that matches... The corresponding optimal power generation plan vector is denoted as Will As the power generation plan of provincial grid a (a=1,2,...,A) at time t, it realizes the joint dispatch of grid and province based on the provincial grid's equivalent value.

[0106] This invention also provides a network-province joint scheduling system based on provincial network equivalence, wherein the system includes:

[0107] The first module is used to establish the optimal power generation plan sequence for each provincial grid;

[0108] The second module is used to establish equivalent models for each provincial power grid based on the optimal power generation plan sequence of each provincial power grid.

[0109] The third module is used to jointly schedule the power generation plans of each province based on the equivalent models of each provincial grid, and obtain the inter-provincial interconnection line plan and the power generation plan of the equivalent models of each provincial grid.

[0110] The fourth module is configured to establish the actual power generation plan of each provincial grid based on the power generation plan of the equivalent model of the provincial grid and the optimal power generation plan of each provincial grid.

[0111] Further, the establishing the optimal power generation plan sequence of each provincial grid comprises:

[0112] calculating the minimum and maximum power generation capacity of each provincial grid to establish a load level sequence that can be borne by the power generators of each provincial grid;

[0113] obtaining the optimal power generation plan under different load levels within each provincial grid based on the load level sequence that can be borne by the power generators of each provincial grid.

[0114] The grid-provincial joint dispatching method and system based on the equivalent of the provincial grid can quickly adjust the grid-provincial dispatching plan when the load and wind power change, and improve the operation efficiency of the multi-provincial interconnected grid.

[0115] Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0116] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0117] Figure 1 A flow chart of a grid-provincial joint dispatching method based on the equivalent of the provincial grid according to an embodiment of the present application is shown.

[0118] Figure 2 A structure diagram of a grid-provincial joint dispatching system based on the equivalent of the provincial grid according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0119] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to clearly and completely explain the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0120] In addition, in the application, the terms "first", "second" and other similar words do not imply any order, quantity and importance, but are only used to distinguish different elements.

[0121] In the application, "provincial network" refers to a provincial power grid; "network" in "network province" refers to a cross-provincial power grid containing multiple provinces, and "province" refers to a power grid of a province, wherein the dispatching center of "network" is called "network dispatching", and the dispatching center of "province" is called "provincial dispatching";

[0122] In the application, "network dispatching" is a higher level dispatching center than provincial dispatching, and "network dispatching" formulates a generation plan of tie lines between provinces, and "provincial dispatching" formulates a generation plan within a province.

[0123] The application provides a network-province joint dispatching method based on provincial network equivalence, which first takes each provincial power grid (provincial network) as an analysis object, comprehensively considers generator operation constraints within the provincial network and upper and lower limit constraints of power transmission lines within the provincial network, takes the minimum generation cost within a province as an optimization target, obtains optimal generation plans of each provincial network under different load levels, and forms an optimal generation plan sequence.

[0124] Then, the optimal generation plan sequence is used to equivalently calculate the optimal generation plan sequence, and an equivalent cost function model, an equivalent climbing function model and an equivalent inter-provincial tie line power function model corresponding to the optimal generation plan sequence are calculated.

[0125] Finally, the above provincial network equivalence model is sent to the dispatching center of the network dispatching, the dispatching center of the network dispatching takes minimizing the total generation cost of the whole network as an optimization target, takes power balance of the whole network, climbing ability of each provincial network equivalence model and upper and lower limits of inter-provincial tie line power as optimization constraints, and optimizes to obtain the inter-provincial tie line plan and the generation plan of each provincial network equivalence model. Each provincial network obtains the final generation plan of each provincial network according to the generation plan of the equivalence model and the optimal generation plan sequence established in the foregoing, so as to realize the network-province joint dispatching based on the provincial network equivalence.

[0126] The application provides a network-province joint dispatching method based on provincial network equivalence, which first takes each provincial power grid (provincial network) as an analysis object, comprehensively considers generator operation constraints within the provincial network and upper and lower limit constraints of power transmission lines within the provincial network, takes the minimum generation cost within a province as an optimization target, obtains optimal generation plans of each provincial network under different load levels, and forms an optimal generation plan sequence. Figure 1 As shown in the method, the method comprises the following steps:

[0127] Step S1: establishing an optimal generation plan sequence of each provincial network;

[0128] Step S2: based on the optimal generation plan sequence of each provincial network, establishing an equivalence model of each provincial network;

[0129] Step S3: based on the equivalence model of each provincial network, jointly dispatching the generation plan of the network and the province to obtain the inter-provincial tie line plan and the generation plan of the equivalence model of each provincial network.

[0130] Step S4: obtaining the actual generation plan of each provincial grid (i.e. obtaining the actual generation plan of each thermal power unit in each provincial grid) based on the generation plan of the provincial grid equivalent model and the optimal generation plan sequence of each provincial grid, so as to realize the grid-provincial joint dispatching of the provincial grid equivalent.

[0131] A grid-provincial joint dispatching method based on provincial grid equivalence will be described in detail below.

[0132] In an embodiment of the present application, step S1 comprises:

[0133] The minimum generation cost in the province is taken as the optimization objective to obtain the optimal generation plan of each provincial grid under different load levels, so as to form the optimal generation plan sequence.

[0134] The specific steps of step S1 are as follows:

[0135] Step S11: calculating the minimum and maximum generation capacity of each provincial grid to establish the load level sequence that can be borne by the generators of each provincial grid;

[0136] Step S12: based on the load level sequence that can be borne by the generators of each provincial grid, the optimal generation plan under different load levels in each provincial grid is established.

[0137] In this embodiment, in step S11, the calculation of the minimum and maximum generation capacity of each provincial grid comprises:

[0138] The minimum and maximum generation capacity of each provincial grid is calculated in sequence by the following expressions (1) and (2):

[0139]

[0140]

[0141] Wherein, N a represents the number of generator units of the a-th provincial grid, A represents the number of provincial grids, a represents the number of the provincial grid, i represents the number of the generator in the provincial grid, and are the maximum and minimum generation capacity of the a-th provincial grid, respectively, and p a,i are the maximum and minimum technical output of the i-th unit in the a-th provincial grid, respectively, is the meaning of "arbitrary" in mathematics.

[0142] In this embodiment, in step S11, the establishment of the load level sequence that can be borne by the generators of each provincial grid comprises:

[0143] The load level sequence that each provincial grid generator can undertake is established by the following expressions (3)-(6):

[0144]

[0145]

[0146]

[0147]

[0148] wherein, L a is the load level sequence of the a-th provincial grid, m is the number of elements in the sequence, represents the values in the load level sequence arranged from small to large, the minimum value is equal to the minimum generation capacity of the a-th provincial grid is the maximum value is equal to the maximum generation capacity of the a-th provincial grid the m-th element in the sequence is M is the number of elements in the load level sequence, which is a value specified in advance, when the provincial grid generator set is small, M can take a first threshold value (exemplarily, 1000 can be taken), when the provincial grid generator set is large, M can take a second threshold value (exemplarily, 10000 can be taken).

[0149] In an embodiment of the present application, in step S12, the optimal generation plan under different load levels in the province is obtained, comprising:

[0150] Step S121: establishing a target function of the provincial optimal dispatch;

[0151] Step S122: establishing a constraint condition of the provincial optimal dispatch;

[0152] Step S123: obtaining the optimal generation plan under different load levels in the province according to the target function and the constraint condition.

[0153] In the embodiment, in step S121, the target function of the provincial optimal dispatch is established, comprising:

[0154] The target function of the provincial optimal dispatch is established by the following expression (7):

[0155]

[0156] wherein, α a,i , β a,i , γ a,i are respectively the quadratic term coefficient, the linear term coefficient and the constant term of the i-th thermal power generator of the a-th provincial grid, ca,m represents the minimum fuel cost of the ath provincial grid when the load level is a,i,m represents the optimal generation plan of the ith thermal power unit in the ath provincial grid when the load level is

[0157] In this embodiment, in step S122, the constraint conditions for establishing the provincial optimization scheduling include:

[0158] 1) Establish the provincial grid power balance constraint, as shown in the following expression (8):

[0159]

[0160] wherein N a represents the number of generating units in the ath provincial grid, represents the mth element of the load level sequence of the ath provincial grid, that is, the load size of the ath provincial grid at this time is

[0161] 2) Establish the minimum and maximum technical output constraints of the provincial grid generating units, as shown in the following expression (9):

[0162]

[0163] wherein, and p a,i are the maximum and minimum technical output of the ith unit in the ath provincial grid, respectively.

[0164] 3) Establish the upper and lower limits of the transmission power of the provincial grid transmission line, as shown in the following expression (10):

[0165]

[0166] wherein PL a,l represents the upper limit of the active power on the lth line in the ath provincial grid, PL represents the upper limit of the active power, G l,a,i represents the transfer distribution factor of the lth line in the ath provincial grid to the ith thermal power unit, the value of the transfer distribution factor can be obtained from the provincial grid dispatching center, represents the transmission power on the lth line in the ath provincial grid when the load level is

[0167] In step S123, the optimal unit generation plan of all provincial grids under different load levels is obtained (i.e., solved), including:

[0168] for all provincial grids, that is, ​​Solving the expressions (7)-(10) when m takes values from 1 to M, the optimal generation schedule p at the load level a,i,m (m=1, 2,..., M) is obtained.

[0169] In the embodiment, the optimal generation schedule sequence of each provincial grid at different load levels can also be established by the optimal generation schedules of all provincial grids at different load levels, as shown in the following expression (11):

[0170]

[0171] wherein, Z a represents the optimal generation schedule sequence of the a-th provincial grid at different load levels, represents the optimal generation schedule vector of the a-th provincial grid at the load level In the embodiment, the expression (12) of the optimal generation schedule vector is as follows:

[0172]

[0173] wherein, [] represents a vector composed of real numbers, [] T represents the transposition operation of the vector, p a,i,m (i=1, 2,..., N a represents the optimal planned output of the i-th thermal power unit in the a-th provincial grid at the load level .

[0174] In one embodiment of the present application, in step S2, the establishment of the equivalent model of each provincial grid comprises:

[0175] Step S21: establishing an equivalent cost function model of each provincial grid;

[0176] Step S22: establishing an equivalent ramp function model of each provincial grid;

[0177] Step S23: establishing an equivalent inter-provincial tie-line power function model of each provincial grid.

[0178] In the embodiment, in step S21, the establishment of the equivalent cost function model of each provincial grid comprises:

[0179] The least square method is used to fit the points in the set represented by the following expression (13) by using a piecewise quadratic function to obtain the equivalent cost function model of the a-th provincial grid:

[0180]

[0181] wherein, represents the load level of the a-th provincial grid the sum of the generation outputs at the time, i.e., expression (14):

[0182]

[0183] wherein c a,m (m = 1, 2,..., M) is the minimum fuel cost of the athprovincial grid at the load level at the time, wherein represents the mth element of the load level sequence of the athprovincial grid, i.e., the load size of the athprovincial grid at the time is denoted as CT a .

[0184] In this embodiment, in step S22, the establishment of the equivalent ramp function model of each provincial grid comprises:

[0185] The least square method is used to fit the points in the set represented by expression (15) using a piecewise linear function to obtain the equivalent upward ramp function model of the athprovincial grid:

[0186]

[0187] wherein RU a,m (m = 1, 2,..., M) represents the upward ramping capability of the athprovincial grid at the total generation output at the time, and the expression (16) of RU a,m is as follows:

[0188]

[0189]

[0190] wherein represents the maximum upward ramping range of the ith unit in the athprovincial grid when the generation output of the unit is p a,i,m , and p a,i,m represents the optimal generation plan of the ith thermal power unit in the athprovincial grid at the load level at the time, represents the mth element of the load level sequence of the athprovincial grid, i.e., the load size of the athprovincial grid at the time is the minimum technical output of the ith unit in the athprovincial grid, represents the upward ramping capability of the ith unit in the athprovincial grid per unit time, and ΔT represents the scheduling time interval when the provincial grid is jointly scheduled, and the fitted equivalent upward ramping function model of the athprovincial grid is denoted as RU a ;

[0191] The least square method is used to fit the points in the set represented by the following expression (18) by using a piecewise linear function to obtain the equivalent downward ramping function model of the ath provincial network:

[0192]

[0193] wherein RD a,m (m = 1, 2,..., M) represents the downward ramping capability of the ath provincial network when the power generation output is , as shown in the following expression (19):

[0194]

[0195]

[0196] wherein, represents the maximum downward ramping range of the ith unit in the ath provincial network when the power generation output is p a,i,m , and represents the downward ramping capability of the ith unit in the ath provincial network per unit time; the fitted equivalent downward ramping function model of the ath provincial network is denoted as RD a , p a, i is the minimum technical output of the ith unit in the ath provincial network.

[0197] In this embodiment, in step S23, the establishment of the equivalent inter-provincial tie-line power function model of each provincial network comprises:

[0198] The least square method is used to fit the points in the set represented by the following expression (21) by using a piecewise linear function to obtain the equivalent inter-provincial tie-line power function model of the ath provincial network for the φ (φ = 1, 2,..., Φ) inter-provincial tie lines:

[0199]

[0200] wherein φ represents the number of the inter-provincial tie line, Φ represents the number of the inter-provincial tie lines, represents the power of the φ inter-provincial tie line of the ath provincial network when the power generation output is , and its expression (22) is as follows:

[0201]

[0202] wherein G φ,a,iH represents the transfer distribution factor of the active power output of the φ-th inter-provincial tie line to the i-th thermal power generating unit in the a-th provincial grid. The value of the transfer distribution factor can be obtained from the dispatch center of the grid dispatching center. The equivalent inter-provincial tie line power function of the a-th provincial grid to the φ-th (φ=1,2,...,Φ) inter-provincial tie line is denoted as H. a,φ p a,i,m This indicates that the i-th thermal power unit in the a-th provincial grid is at a load level of The optimal power generation plan at that time.

[0203] In one embodiment of the present invention, step S3, obtaining the inter-provincial interconnection plan and the power generation plan of the equivalent model of each provincial grid, includes:

[0204] Step S31: Based on the equivalent model of the provincial grid, establish the objective function for joint scheduling of power generation plans between the grid and the province;

[0205] Step S32: Based on the equivalent model of the provincial grid, establish the constraints for joint dispatch of power generation plans between the grid and the province;

[0206] Step S33: Based on the objective function and constraints of the joint scheduling of power generation plans between the grid and the province, obtain the inter-provincial interconnection line plan and the power generation plan of each provincial grid equivalent model.

[0207] In this embodiment, in step S31, the objective function for the joint scheduling of power generation plans between the provincial grid and the province is established based on the equivalent model of the provincial grid, and its expression (23) is as follows:

[0208]

[0209] Where t represents the scheduling period number, T represents the number of scheduling periods, and CT a Let Q represent the equivalent cost function model of the a-th provincial power grid, which is a piecewise quadratic function of the total power generation output of the a-th provincial power grid. a,t This represents the total power generation output of the a-th provincial grid during the t-th scheduling period.

[0210] In this embodiment, step S32, which establishes the constraints for joint scheduling of power generation plans between the provincial grid and the grid based on the equivalent model of the provincial grid, includes:

[0211] 1) Establish the power balance constraint for joint scheduling between the grid and the province, as shown in expression (24):

[0212]

[0213] Among them, W a,t S represents the total wind power output of the a-th provincial grid at dispatch time t. a,t Let T represent the total load power of the a-th provincial grid at scheduling time t, and let T represent the number of scheduling periods.

[0214] 2) Establish the upper and lower limit constraints of the equivalent model of each provincial grid, and the expression (25) is as follows:

[0215]

[0216] wherein, and are the maximum and minimum power generation capacity of the a-th provincial grid, respectively;

[0217] 3) Establish the ramping constraints of the equivalent model of each provincial grid, and the expression (26) is as follows:

[0218] -RD a (Q a,t )≤Q a,t+1 -Q a,t ≤RU a (Q a,t ), t = 1, 2,..., T-1 (26)

[0220] wherein, RU a and RD a are the equivalent upward and downward ramping function models of the a-th provincial grid established in the entire step 2, respectively;

[0221] 4) Establish the reserve constraints of the joint dispatch of the grid and the province, and the expression is as follows:

[0222]

[0223]

[0224] wherein, PU a,t and PD a,t are the upward and downward reserve quantities provided by the a-th provincial grid at the dispatch time t, respectively, and are the minimum upward and downward reserve quantities required by the entire grid at the dispatch time t, respectively;

[0225] 5) Establish the inter-provincial tie-line power constraints of the joint dispatch of the provincial grid, and the expression (29) is as follows:

[0226]

[0227] wherein, PH φ represents the active power upper limit of the φ-th inter-provincial tie line, H a,φ represents the equivalent inter-provincial tie-line power function of the a-th provincial grid to the φ-th inter-provincial tie line, HW a,φ and HD a,φ represent the total wind power W a,t and the total load power S in the a-th provincial grid, respectively.a,t The transmission power generated on the φth inter-provincial interconnection line can be calculated using DC power flow, and HW a,φ and HD a,φ All are constants.

[0228] In this embodiment, step S33 involves obtaining (i.e. solving) the inter-provincial interconnection line plan and the power generation plan of the equivalent models of each provincial grid, including:

[0229] The branch-and-bound method is used to solve the objective function and constraints of the joint scheduling of power generation plans of the grid and provinces, resulting in the planned total power output of the a-th province at time t as Q. a,t The inter-provincial connecting line φ is planned as TL at time t. t , where TL t The expression (30) is:

[0230]

[0231] In one embodiment of the present invention, step S4: Based on the power generation plan of the provincial grid equivalent model and the optimal power generation plan of each provincial grid, establish the actual power generation plan of each provincial grid, including:

[0232] The provincial power grid a (a = 1, 2, ..., A) generates electricity at time t according to the equivalent model of the provincial power grid, i.e., Q. a,t Retrieve the established load level sequence and find the elements in the load level sequence that correspond to Q. a,t The closest value is denoted as Then, retrieve the established optimal power generation plan sequence and find the one that matches... The corresponding optimal power generation plan vector is denoted as Will As the power generation plan of provincial grid a (a=1,2,...,A) at time t, it realizes the joint dispatch of grid and province based on the provincial grid's equivalent value.

[0233] On the other hand, such as Figure 2 As shown, the present invention also provides a network-province joint scheduling system based on provincial network equivalence, wherein the system includes:

[0234] The first module is used to establish the optimal power generation plan sequence for each provincial grid;

[0235] The second module is used to establish equivalent models for each provincial power grid based on the optimal power generation plan sequence of each provincial power grid.

[0236] The third module is used to jointly schedule the power generation plans of each province based on the equivalent models of each provincial grid, and obtain the inter-provincial interconnection line plan and the power generation plan of the equivalent models of each provincial grid.

[0237] The fourth module is used for establishing the actual power generation plan of each provincial network based on the power generation plan of the provincial network equivalent model and the optimal power generation plan of each provincial network, so as to realize the grid-provincial network joint dispatching of the provincial network equivalent.

[0238] In the present application, the functions and modes realized by each module in the grid-provincial network joint dispatching system based on the provincial network equivalent correspond to the functions and modes realized by each step in the grid-provincial network joint dispatching method based on the provincial network equivalent, and thus will not be described here.

[0239] Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A grid-province joint dispatching method based on grid-province equivalence, wherein, The method comprises: establishing optimal generation scheduling sequences of each provincial grid, comprising: calculating minimum and maximum generation capacities of each provincial grid to establish load level sequences that each generator of each provincial grid can undertake; obtaining optimal generation scheduling under different load levels in each province based on the load level sequences that each generator of each provincial grid can undertake, comprising: establishing an objective function of optimal scheduling in each province; ， wherein, denotes the number of generator units in the th provincial grid, denotes the number of the provincial grid, i denotes the number of the generator in the provincial grid, denotes the quadratic term coefficient, the linear term coefficient and the constant term of the fuel cost of the th thermal generator unit in the i th provincial grid, respectively, denotes the minimum fuel cost of the th provincial grid when the load level is , denotes the optimal generation schedule of the th thermal generator unit in the i th provincial grid when the load level is , denotes the th element of the load level sequence of the m th provincial grid, i.e. the load size of the th provincial grid at this time is , m is the number of the element in the load level sequence; based on the optimal generation scheduling sequences of each provincial grid, establishing equivalent models of each provincial grid, comprising: using a least square method, using a piecewise quadratic function to fit the set The points within the inner circle are fitted to obtain the first equivalent cost function model of the provincial network , wherein, denotes the sum of the generation output of the provincial grid at the load level , is the minimum fuel cost of the provincial grid at the load level , M is the number of elements in the sequence of load levels, which is a value specified in advance; based on the equivalent models of each provincial grid, jointly scheduling the generation scheduling of each provincial grid to obtain the generation scheduling of each provincial grid equivalent model and the inter-provincial tie line plan, comprising: based on the equivalent models of each provincial grid, establishing an objective function of joint scheduling of the generation scheduling of each provincial grid ， wherein, t denotes a number of scheduling periods, T denotes a number of scheduling periods, A denotes a number of provinces, is the total generation output of the t th scheduling period in the th province. based on the generation scheduling of the equivalent models of each provincial grid and the optimal generation scheduling of each provincial grid, establishing actual generation scheduling of each provincial grid to realize joint scheduling of each provincial grid equivalent model and the inter-provincial tie line plan.

2. The grid-province joint dispatching method based on grid-province equivalence according to claim 1, wherein, The calculation of the minimum and maximum generation capacities of each provincial grid comprises: The minimum and maximum generation capacities of each provincial grid are calculated in sequence by the following expressions: ， ， wherein, and are the maximum and minimum generation capacity of the th provincial grid, respectively, and are the maximum and minimum technical output of the th unit in the i th provincial grid, respectively, are denoted as "arbitrary".

3. The grid-province joint dispatching method based on grid-province equivalence according to claim 1, wherein, The establishment of the load level sequences that each generator of each provincial grid can undertake comprises: The load level sequences that each generator of each provincial grid can undertake are established by the following expressions: ， ， ， ， wherein, is the load level sequence of the th provincial grid, represents the values arranged in ascending order in the load level sequence, the minimum value is equal to the minimum generation capacity of the th provincial grid , the maximum value is equal to the maximum generation capacity of the th provincial grid , the m th element in the sequence is , represents "arbitrary".

4. The grid-province joint dispatching method based on grid-province equivalence according to claim 1, wherein, The optimal generation scheduling under different load levels in each province further comprises: establishing constraint conditions of optimal scheduling in each province; obtaining the optimal generation scheduling under different load levels in each province according to the objective function and the constraint conditions.

5. The grid-province joint dispatching method based on grid-province equivalence according to claim 4, wherein, The establishment of the constraint conditions of optimal scheduling in each province comprises: 1) establishing a provincial grid power balance constraint: ； 2) establishing minimum and maximum technical output constraints of provincial grid generators: ， wherein, and are the maximum and minimum technical output of the th unit in the i th province network, respectively, is denoted as "arbitrary"; 3) establishing upper and lower limits of transmission power constraints of provincial grid transmission lines: ， wherein, denotes the upper limit of the active power on the th line in the th provincial grid, denotes the transfer distribution factor of the th line in the th provincial grid to the i th thermal power unit, denotes the transmission power generated by the th line in the th provincial grid at the load level .

6. The grid-province joint dispatching method based on grid-province equivalence according to claim 5, wherein, obtaining the optimal generation scheduling of all provincial grids under different load levels comprises: For all provincial networks, i.e. When m is taken from 1 to M , the objective function of the intra-provincial optimal dispatch and the constraint conditions of the intra-provincial optimal dispatch are solved to obtain the optimal generation plan at the load level .

7. The grid-province joint dispatching method based on grid-province equivalence according to any one of claims 1-6, wherein, The establishment of the equivalent models of each provincial grid comprises: establishing an equivalent cost function model of each provincial grid; establishing an equivalent ramp function model of each provincial grid; establishing an equivalent inter-provincial tie line power function model of each provincial grid.

8. The grid-province joint dispatching method based on grid-province equivalence according to claim 7, wherein, The establishment of the equivalent ramp function model of each provincial grid comprises: The least square method is used to fit the points in the following set by using piecewise linear function to obtain the equivalent upward climbing function model of the first a provincial network: ， wherein, represents the up-ramp capability of the th provincial grid when the total power generation is RU a,m The expression is as follows:​ ， ， wherein, denotes the maximum upward ramping range of the i-th unit in the j-th provincial grid when the power output of the i-th unit is i is the minimum technical output of the i-th unit in the j-th provincial grid, i denotes the upward ramping capacity of the i-th unit in the j-th provincial grid per unit time, i denotes the dispatching time interval when the provincial grids are jointly dispatched, and the fitted equivalent upward ramping function model of the j-th provincial grid is denoted as ;​​​​​​​​ The least square method is used to fit the points in the following set by using piecewise linear function to obtain the equivalent downward ramp function model of the first a provincial network: ， wherein, represents the down ramping ability of the provincial grid when the power generation output is Pmax, ， ， in, Indicates the first The first in the provincial network i Each generating unit has a power output of The maximum downhill range at that time Indicates the first The first in the provincial network i The downhill climbing ability of each unit per unit time; the first step obtained from the above fitting. The equivalent downward ramp function model of the provincial network is denoted as: , For the first The first in the provincial network i Minimum technical output of each unit.

9. The grid-province joint dispatching method based on grid-province equivalence according to claim 8, wherein, The establishment of the equivalent inter-provincial tie line power function model of each provincial grid comprises: The least square method is used to fit the points in the following set by using the piecewise linear function to obtain the equivalent inter-provincial tie-line power function model of the first inter-provincial tie-line of the first provincial network ， wherein, denotes the number of the interregional tie line, denotes the number of the interregional tie line, denotes the power of the th interregional tie line of the th regional grid when the power output of the th regional grid is Pth, its expression is as follows: ， wherein, represents the th inter-provincial tie-line to the th provincial grid, and the transfer distribution factor of the i th unit in the th provincial grid, which can be obtained from the dispatching center of the grid operator. The equivalent inter-provincial tie-line power function of the th provincial grid to the th inter-provincial tie-line is denoted as 10. The grid-province joint dispatching method based on grid-province equivalence according to any one of claims 1-5, wherein, The obtaining of the generation scheduling of each provincial grid equivalent model and the inter-provincial tie line plan further comprises: based on the equivalent models of each provincial grid, establishing constraint conditions of joint scheduling of the generation scheduling of each provincial grid; based on the objective function of joint scheduling of the generation scheduling of each provincial grid and the constraint conditions of joint scheduling of the generation scheduling of each provincial grid, obtaining the generation scheduling of each provincial grid equivalent model and the inter-provincial tie line plan.

11. The grid-province joint dispatching method based on grid-province equivalence according to claim 10, wherein, The establishment of the constraint conditions of joint scheduling of the generation scheduling of each provincial grid based on the equivalent models of each provincial grid comprises: 1) establishing a power balance constraint of joint scheduling of each provincial grid, expressed as follows: ， wherein, denotes the total wind power output of the th provincial grid at the dispatch time t point, denotes the total load power of the th provincial grid at the dispatch time t point, T denotes the number of dispatch time periods; 2) establishing upper and lower limits of generation output constraints of each provincial grid equivalent model, expressed as follows: ， wherein, and are the maximum and minimum generation capacity of the provincial grid, respectively. 3) establishing ramp constraints of each provincial grid equivalent model, expressed as follows: ， in, and The first ones established in order are respectively Equivalent upward and downward ramp function models for provincial networks; 4) establishing a reserve constraint of joint scheduling of each provincial grid, expressed as follows: ， ， in, and The first Provincial networks during scheduling t The provided upward and downward reserve quantities, and Scheduling time t Minimum upstream and downstream reserve quantities required for the entire network; 5) establishing an inter-provincial tie line power constraint of joint scheduling of each provincial grid, expressed as follows: ， in, Indicates the first The upper limit of active power for inter-provincial connecting lines. Indicates the first The provincial network for the first The equivalent inter-provincial tie line power function of the inter-provincial tie line. and They represent the number respectively. Total wind power in provincial grids and total load power In the The power transmission generated on the inter-provincial connection line.

12. The grid-province joint dispatching method based on grid-province equivalence according to claim 11, wherein, solving the generation scheduling of each provincial grid equivalent model and the inter-provincial tie line plan comprises: The branch-and-bound method is used to solve the objective function and constraints of the joint scheduling of power generation plans between the grid and the province, resulting in the... The provincial network is in real time t The total planned power generation output is , No. Inter-provincial connection lines at time t The link plan is for .

13. The grid-province joint dispatching method based on grid-province equivalence according to claim 1, wherein, The actual power generation plan of each provincial network is obtained based on the power generation plan of the equivalent model of the provincial network and the optimal power generation plan of each provincial network, and includes: Provincial Network Based on the provincial network's equivalent model at time... t The power generation plan, namely Retrieve the established load level sequence and find the elements in the load level sequence that match... The closest value is denoted as Then, the established optimal power generation plan sequence is retrieved, and the sequence is found to be consistent with... The corresponding optimal power generation plan vector is denoted as ,Will As a provincial network At any moment t The power generation plan will be implemented to achieve joint dispatching between the provincial and grid-province grids based on the provincial grid's equivalent value.

14. A grid-province joint dispatching system based on province grid equivalence, for implementing a grid-province joint dispatching method based on province grid equivalence according to any one of claims 1-13, wherein, The system includes: A first module for establishing an optimal power generation plan sequence of each provincial network; A second module for establishing an equivalent model of each provincial network based on the optimal power generation plan sequence of each provincial network; A third module for jointly scheduling the power generation plan of the network and the province based on the equivalent model of each provincial network, to obtain a tie line plan between provinces and a power generation plan of the equivalent model of each provincial network; A fourth module for establishing an actual power generation plan of each provincial network based on the power generation plan of the equivalent model of the provincial network and the optimal power generation plan of each provincial network.

15. The grid-province joint dispatch system based on grid-province equivalence according to claim 14, wherein, The optimal power generation plan sequence of each provincial network includes: Calculating the minimum and maximum power generation capacity of each provincial network to establish a load level sequence that can be borne by the generators of each provincial network; Based on the load level sequence that can be borne by the generators of each provincial network, the optimal power generation plan under different load levels in each province is obtained.

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