CN112260268A - Method for obtaining system flexibility domain - Google Patents

Abstract

The invention discloses a method for acquiring a system flexibility domain, which comprises the following steps of 1) acquiring a basic operation point; 2) solving a model in a flexible domain; 3) optimizing the flexible domain solution model to obtain a flexible domain simple solution model; 4) and acquiring a flexibility domain. According to the invention, the workload and the working time are greatly reduced by improving the solving mode of the step (2), and the time for acquiring the system flexibility domain is greatly shortened.

Description

Method for obtaining system flexibility domain

Technical Field

The invention relates to the field of power system analysis, in particular to a method for acquiring a system flexibility domain.

Background

Under the common recognition of main countries around the world for coping with climate change, the rapid development of renewable energy power generation technologies represented by wind and light is promoted. However, the inherent fluctuation and uncertainty of wind and light power generation output cause the problem of large-scale wind and light power generation absorption to be increasingly highlighted, and the risk of safe and stable operation of the system is continuously aggravated. The concept of the flexibility domain of the system is emerging, and the concept refers to the upper and lower boundaries of the renewable energy sources which can be consumed by the system under the situation of the existing basic operation point, namely the maximum fluctuation interval of the output of the renewable energy sources which can be allowed by the system.

The size of the flexibility domain of the system is influenced by flexibility resources, such as the minimum technical output and the climbing speed of the traditional conventional unit. At present, a lot of system flexibility domain researches are carried out, but most of the system flexibility domain researches are obtained by constructing a scheduling model for calculation, but the problem is a two-stage robust planning problem, generally needs to be solved and obtained through Benders decomposition or CC & G algorithm, and is high in calculation complexity and long in time.

Disclosure of Invention

The present invention is directed to a method for obtaining a system flexibility domain, so as to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: a method for obtaining a system flexibility domain, comprising the steps of:

1) obtaining a basic operation point;

the objective function is as follows:

in the formula, P_g,t ^bThe method comprises the following steps of (1) setting a basic operation point of a thermal power generating unit g in a time period t; p_k,t ^bA basic operation point of the wind field k in a time period t; p_k,t,preThe predicted output of the wind field k in the time period t is obtained; c_g() is a g cost function of the thermal power generating unit; c_wPunishment coefficient for abandoned wind; g is a thermal power generating unit set; k is a wind field set; t is a set of periods.

In the formula, D_tThe load demand of the system period t.

In the formula, SF_n,lA power transfer distribution factor for node n to line l; f_l,maxIs the maximum capacity of line l; d_n,tThe load demand for node n during time period t.

P_g,min≤P_g,t ^b≤P_g,max

In the formula, P_g,min、P_g,maxRespectively representing the upper and lower output limits of the thermal power generating unit g.

0≤P_k,t ^b≤P_k,t,pre

2) Solving a model in a flexible domain;

the objective function is as follows:

in the formula, σ_kWeighting the k flexibility domain of the wind field; p_k,t,UBTake up the upper bound, P, for wind farm k_k,t,LBA lower bound is absorbed for a wind field k, and the lower bound and the wind field k are flexibility domains; p_k,rateOf wind field kAnd (5) installing capacity.

In the formula, P_g,t ^*The method comprises the steps of solving operation points of a thermal power generating unit g time period t in a flexible domain; p_k,t ^*And (5) solving the operating point of the wind field k period t in the flexible domain.

P_g,t ^b-Δ_g,dn≤P_g,t ^*≤P_g,t ^b+Δ_g,up，P_g,min≤P_g,t ^*≤P_g,max

In the formula,. DELTA._g,up、Δ_g,dnRespectively the up-down climbing capacity of the unit g.

0≤P_k,LB≤P_k,t ^b≤P_k,UB≤P_k,rate

3) Optimizing the flexible domain solution model to obtain a flexible domain simple solution model;

its upper bound objective function:

P_g,t ^b-Δ_g,dn≤P_g,t ^*≤P_g,t ^b+Δ_g,up，P_g,min≤P_g,t ^*≤P_g,max

P_k,t ^b≤P_k,t ^*≤P_k,rate

its lower bound objective function:

P_g,t ^b-Δ_g,dn≤P_g,t ^*≤P_g,t ^b+Δ_g,up，P_g,min≤P_g,t ^*≤P_g,max

P_k,t ^b≤P_k,t ^*≤P_k,rate

4) flexible domain acquisition

In the formula, T_NIs the number of time segments.

Compared with the prior art, the invention has the beneficial effects that: the flexible domain solving model in the step (2) is a two-stage robust planning model, the calculation complexity is high, the solving is complex, generally, the flexible domain solving model needs to be obtained by solving through Benders decomposition or CC & G algorithm, the calculation complexity is high, the time is long, and the working efficiency is low.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a system flexibility domain of an embodiment;

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The calculation is exemplified by taking a power generation reliability test system IEEE-RTS79 as an example, a wind field is added to a node 1 and a node 2, wherein the wind abandonment penalty is 0.3 Rmb/kWh, and other parameters are referred to an IEEE-RTS79 test system.

1) Base operating point acquisition

Obtaining P through a base operating point model_g,t ^b、P_k,t ^b。

2) Flexible domain upper bound acquisition

Inputting a basic operating point and an up-down climbing parameter delta of the unit_g,up、Δ_g,dnObtaining by a flexible domain upper bound model

3) Flexible domain lower bound acquisition

Inputting a basic operating point and an up-down climbing parameter delta of the unit_g,up、Δ_g,dnBy flexible domain lower bound model acquisition

4) Obtaining a system flexibility domain, [ P ]_LB；P_UB]The results are shown in FIG. 2.

Thus, the method provided by the invention is implemented.

It is worth mentioning that the present invention can calculate not only the flexibility domain of renewable energy, but also the flexibility domain of other uncertain resources, such as power load.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (1)

1. A method for obtaining a system flexibility domain, comprising the steps of:

1) obtaining a basic operation point;

the objective function is as follows:

in the formula, P_g,t ^bThe method comprises the following steps of (1) setting a basic operation point of a thermal power generating unit g in a time period t; p_k,t ^bA basic operation point of the wind field k in a time period t; p_k,t,preThe predicted output of the wind field k in the time period t is obtained; c_g() is a g cost function of the thermal power generating unit; c_wPunishment coefficient for abandoned wind; g is a thermal power generating unit set; k is a wind field set; t is a time interval set;

in the formula, D_tLoad demand for system time period t;

in the formula, SF_n,lA power transfer distribution factor for node n to line l; f_l,maxIs the maximum capacity of line l; d_n,tLoad demand for node n at time period t;

P_g,min≤P_g,t ^b≤P_g,max

in the formula, P_g,min、P_g,maxRespectively representing the upper limit and the lower limit of the output of the thermal power generating unit g;

0≤P_k,t ^b≤P_k,t,pre

2) solving a model in a flexible domain;

the objective function is as follows:

in the formula, σ_kWeighting the k flexibility domain of the wind field; p_k,t,UBTake up the upper bound, P, for wind farm k_k,t,LBA lower bound is absorbed for a wind field k, and the lower bound and the wind field k are flexibility domains; p_k,rateThe installed capacity of a wind field k;

in the formula, P_g,t ^*The method comprises the steps of solving operation points of a thermal power generating unit g time period t in a flexible domain; p_k,t ^*Operating points in the flexible domain solution for the k time period t of the wind field;

P_g,t ^b-Δ_g,dn≤P_g,t ^*≤P_g,t ^b+Δ_g,up，P_g,min≤P_g,t ^*≤P_g,max

in the formula,. DELTA._g,up、Δ_g,dnThe up-down climbing capacity of the unit g is respectively;

0≤P_k,LB≤P_k,t ^b≤P_k,UB≤P_k,rate

3) optimizing the flexible domain solution model to obtain a flexible domain simple solution model;

its upper bound objective function:

P_g,t ^b-Δ_g,dn≤P_g,t ^*≤P_g,t ^b+Δ_g,up，P_g,min≤P_g,t ^*≤P_g,max

P_k,t ^b≤P_k,t ^*≤P_k,rate

its lower bound objective function:

P_g,t ^b-Δ_g,dn≤P_g,t ^*≤P_g,t ^b+Δ_g,up，P_g,min≤P_g,t ^*≤P_g,max

P_k,t ^b≤P_k,t ^*≤P_k,rate

4) flexible domain acquisition

[P_LB；P_UB]，

In the formula, T_NIs the number of time segments.

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