Method for real-time scheduling of multi-energy complementary micro-grids based on rollout algorithm
11095127 · 2021-08-17
Inventors
- Xianxu Huo (Tianjin, CN)
- Ling JIANG (Tianjin, CN)
- Honglei Zhao (Tianjin, CN)
- Baoguo Zhao (Tianjin, CN)
- Xudong Wang (Tianjin, CN)
- Guodong Li (Tianjin, CN)
- Tianchun Xiang (Tianjin, CN)
- Ke Xu (Tianjin, CN)
- Yan Qi (Tianjin, CN)
- Lei Wu (Tianjin, CN)
- Shiqian Ma (Tianjin, CN)
- Jingjing Yan (Tianjin, CN)
- Kai WANG (Nanjing, CN)
- Qingshan Xu (Nanjing, CN)
- Lu Sun (Nanjing, CN)
- Aidong Zeng (Nanjing, CN)
Cpc classification
Y04S40/20
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H02J3/32
ELECTRICITY
H02J3/00
ELECTRICITY
H02J3/46
ELECTRICITY
Y04S10/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y02E40/70
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H02J7/0068
ELECTRICITY
G05B2219/2639
PHYSICS
Y02P80/14
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H02J2203/20
ELECTRICITY
Y02E60/00
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
H02J3/46
ELECTRICITY
H02J3/32
ELECTRICITY
Abstract
The invention relates to a method for real-time scheduling of multi-energy complementary micro-grids based on a Rollout algorithm, which is technically characterized by comprising the following steps of: Step 1, setting up a moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids with random new-energy outputs, and establishing constraint conditions for the real-time scheduling; Step 2, establishing a target function of the real-time scheduling; Step 3, dividing a single complete scheduling cycle into a plurality of scheduling intervals, and finding one basic feasible solution meeting the constraint conditions for the real-time scheduling based on a greedy algorithm; and Step 4, finding a solution to the moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids by using the Rollout algorithm based on the basic feasible solution from Step 3. With the consideration of the fluctuations in the new-energy outputs, the present invention solves the problems of low speed and low efficiency of a traditional algorithm at the same time, enabling high-speed efficient multi-energy complementary micro-grid real-time scheduling.
Claims
1. A method for real-time scheduling of multi-energy complementary micro-grids based on a Rollout algorithm, characterized by comprising the following steps of: Step 1, setting up a moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids with random new-energy outputs, and establishing constraint conditions for the real-time scheduling; Step 2, establishing a target function of the real-time scheduling for the moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids with the random new-energy outputs, with the goal of minimum operating cost of a micro-grid system in a moving-horizon Markov decision cycle; Step 3, dividing a single complete scheduling cycle into a plurality of scheduling intervals, and finding one basic feasible solution meeting the constraint conditions for the real-time scheduling based on a greedy algorithm; and Step 4, finding a solution to the moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids by using the Rollout algorithm based on the basic feasible solution from Step 3; wherein the constraint conditions established for the real-time scheduling in Step 1 comprises: micro-grid electric equilibrium constraints, storage battery operating constraints, exchange electric power constraints for the micro-grids and a main grid, and electric power output constraints for combined heat and power equipment; the micro-grid electric equilibrium constraints are as follows:
2. The method for real-time scheduling of multi-energy complementary micro-grids based on the Rollout algorithm according to claim 1, wherein the establishing a target function of the real-time scheduling for the moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids with random new-energy outputs in Step 2 specifically comprises the following sub-steps of: first setting up an operating cost function of the micro-grid system at a single scheduling interval with the goal of minimum operating cost of the micro-grid system at the single scheduling interval, and then establishing a target function of the real-time scheduling with the goal of the minimum operating cost of the micro-grid system in the moving-horizon Markov decision cycle; the operating cost function of the micro-grid system at the single scheduling interval is as follows:
3. The method for real-time scheduling of multi-energy complementary micro-grids based on the Rollout algorithm according to claim 1, wherein Step 3 specifically comprises the following sub-steps of: dividing a complete scheduling cycle into a plurality of scheduling intervals, finding a solution specific to a scheduling optimization problem in each of the scheduling intervals based on the greedy algorithm respectively, and finally synthesizing locally optimal solutions to respective scheduling intervals into one basic feasible solution across the complete scheduling interval.
4. The method for real-time scheduling of multi-energy complementary micro-grids based on the Rollout algorithm according to claim 2, characterized in that the finding a solution specific to a scheduling optimization problem in each of the scheduling intervals based on the greedy algorithm respectively in Step 3 specifically comprises the following sub-steps of: (1) according to the operating cost function of the micro-grid system in a single scheduling interval in Step 2, listing the target function and the constraint conditions as follows:
5. The method for real-time scheduling of multi-energy complementary micro-grids based on the Rollout algorithm according to claim 1, wherein Step 4 specifically comprises the following sub-steps of: (1) supposing the basic feasible solution obtained from Step 3 to be π.sub.b=(A.sub.b,t+1, A.sub.b,t+2, . . . , A.sub.b,t+T−1) to obtain an approximate value of the target function for the minimum operating cost from the time t to the time t+T−1 during one real-time scheduling:
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
DETAILED DESCRIPTION
(2) The embodiments of the present invention are further described in detail below with reference to the accompanying drawings:
(3) The present invention provides a method for real-time scheduling of multi-energy complementary micro-grids based on the Rollout algorithm, which not only takes the fluctuations in the new energy outputs into consideration, but also more effectively solves the problem on the moving-horizon scheduling of the multi-energy complementary micro-grids, solving the problem on the moving-horizon Marcov decision model with the Rollout algorithm. According to the method, at first, the moving-horizon Markov decision process model for multi-energy complementary micro-grid real-time scheduling with random new-energy output is set up, and the constraint conditions and the target function for the real-time scheduling are established; then, a complete scheduling cycle is divided into a plurality of scheduling intervals, and one basic feasible solution meeting the constraint conditions for the real-time scheduling is found based on the greedy algorithm; and finally, a solution to the moving-horizon Markov decision model for multi-energy complementary micro-grids is found by using the Rollout algorithm based on the basic feasible solution above.
(4) A method for real-time scheduling of multi-energy complementary micro-grids based on a Rollout algorithm, as shown in
(5) Step 1, setting up a moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids with random new-energy outputs, and establishing constraint conditions for the real-time scheduling;
(6) where the constraint conditions established for the real-time scheduling in Step 1 comprises: micro-grid electric equilibrium constraints, storage battery operating constraints, exchange electric power constraints for the micro-grids and a main grid, and electric power output constraints for combined heat and power equipment;
the micro-grid electric equilibrium constraints are as follows:
(7)
in the formula, t is a time parameter; p.sup.G(t) is exchange electric power for the micro-grids and the main grid at a time t, which is positive during purchasing of electricity from the main grid and negative during selling of electricity to the main grid; N is the quantity of the combined heat and power equipment; p.sub.i.sup.c(t) is output electric power of the ith combined heat and power equipment at the time t; p.sup.B(1) is charging/discharging power of the storage battery at the time t, which is negative during charging and positive during discharging; p.sup.w(t) is generated output of wind power at the time t; and p.sup.D(t) is an electric load demand at the time t;
the storage battery operating constraints are as follows:
(8)
in the formulae, E(t) and E(t+1) are energy storage levels of the storage battery at the time t and a time t+1 respectively; E and Ē are upper and lower boundaries of the capacity of the storage battery respectively; ΔT is a time interval from the time t to the time t+1; a.sub.c and a.sub.d are charging and discharging efficiencies of the storage battery respectively; p.sup.B(t) is charging/discharging power of the storage battery at the time t, which is negative during charging and positive during discharging; and
the exchange electric power constraints for the micro-grids and the main grid are as follows:
(9)
in the formulae, p.sup.G(t) and p.sup.G(t−1) are exchange electric power between the micro-grids and the main grid at the times t and t−1 respectively, which is positive during purchasing of electricity from the main grid and negative during selling of electricity to the main grid;
the electric power output constraints for the combined heat and power equipment are as follows:
(10)
in the formulae, p.sub.i.sup.c(t) is output electric power of the ith combined heat and power equipment at the time t;
(11) Step 2, establishing a target function of the real-time scheduling for the moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids with random new-energy outputs, with the goal of minimum operating cost of a micro-grid system in a moving-horizon Markov decision cycle;
(12) wherein when in a grid-connected state with the main grid, the multi-energy complementary micro-grids can exchange electricity with the main grid, with energy supply equipment comprising wind driven generators, combined heat and power (CHP) equipment, and storage batteries; and the target function for real-time scheduling is to achieve the minimum operating cost, including system electricity purchasing cost and fuel cost of the CHP equipment, for the micro-grid system.
the establishing a target function of the real-time scheduling for the moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids with random new-energy outputs specifically comprises the following sub-steps of: first setting up an operating cost function of the micro-grid system at a single scheduling interval with the goal of minimum operating cost of the micro-grid system at the single scheduling interval, and then establishing a target function of the real-time scheduling with the goal of the minimum operating cost of the micro-grid system in the moving-horizon Markov decision cycle;
the operating cost function of the micro-grid system at the single scheduling interval is as follows:
(13)
in the formulae, X(t) is a state variable of the micro-grid system at the time t; A(t) is a control variable of the micro-grid system at the time t; c.sub.t(X(t),A(t)) is a function of system operating cost at the single scheduling interval; λ(t) is a grid electricity price at the time t; c is a price of natural gas; F.sub.i.sup.c(t) is a linear function between a gas consumption and an electric output of the ith combined heat and power equipment; and a.sub.i and b.sub.i are coefficients of the linear function between the gas consumption and the electric output of the ith combined heat and power equipment;
the target function of the real-time scheduling is as follows:
(14)
in the formula, J.sub.t(X(t),A(t)) is a function of the operating cost of the micro-grid system in the moving-horizon Markov decision cycle;
(15) Step 3, dividing a single complete scheduling cycle into a plurality of scheduling intervals, and finding one basic feasible solution meeting the constraint conditions for the real-time scheduling based on a greedy algorithm;
(16) where Step 3 specifically comprises the following sub-steps of: dividing a complete scheduling cycle into a plurality of scheduling intervals, finding a solution specific to a scheduling optimization problem in each of the scheduling intervals based on the greedy algorithm respectively, and finally synthesizing locally optimal solutions to respective scheduling intervals into one basic feasible solution across the complete scheduling interval.
the finding a solution specific to a scheduling optimization problem in each of the scheduling intervals based on the greedy algorithm respectively in Step 3 specifically comprises the following sub-steps of: (1) according to the operating cost function of the micro-grid system in a single scheduling interval in Step 2, listing the target function and the constraint conditions as follows:
(17)
the constraint conditions are as follows:
(18)
in the formulae, pb (t)and
(19) Step 4, finding a solution to the moving-horizon Markov decision process model for the real-time scheduling of the multi-energy complementary micro-grids by using the Rollout algorithm based on the basic feasible solution from Step 3.
(20) Step 4 specifically comprises the following sub-steps of: (1) supposing the basic feasible solution obtained from Step 3 to be π.sub.b=(A.sub.b,t+1, A.sub.b,t+2, . . . , A.sub.b,t+T−1) to obtain an approximate value of the target function for the minimum operating cost from the time t to the time t+T−1 during one real-time scheduling:
(21)
in the formula,
(22)
(23) It should be noted that the described embodiments of the present invention are for an illustrative purpose rather than a limiting purpose, and the present invention thus includes but not limited to the embodiments described in the Description of Preferred Embodiments. Any other embodiments obtained by those skilled in the art according to the technical solution of the present invention likewise fall within the protection scope of the present invention.