CN117578601B - Low-carbon power system source load interactive scheduling method and device - Google Patents

Abstract

The present invention proposes a method and device for interactive dispatching of sources and loads in a low-carbon power system, which takes power sources and loads as interactive dispatching objects, and constructs a power time-varying parameter sequence of the source and load to be dispatched according to the output time-varying parameter sequence of the power source to be dispatched and the power time-varying parameter sequence of the load to be dispatched; then, the differential algebraic equation of the power system is linearized at the power system operation point to obtain a power system linearization model, and a power system time-varying parameter system model is obtained according to the power system operation point time-varying parameter sequence; the power time-varying parameter sequence of the source and load to be dispatched is convexly decomposed to obtain a bounded set of coefficient matrices of the power system time-varying parameter system model, and the stability of the power system in the bounded set is judged according to a parameter-dependent quadratic stability criterion; the present invention realizes interactive dispatching of sources and loads in a low-carbon power system, which is of great significance for maximizing the absorption of new energy, activating the adjustable capacity of the load side, and ensuring the safe and stable operation of the low-carbon power system.

Description

A method and device for source-load interactive dispatching of low-carbon power system

Technical Field

The present invention belongs to the technical field of low-carbon power systems, and in particular relates to a source-load interactive scheduling method and device for a low-carbon power system.

Background technique

In order to promote the low-carbonization of the power system and the power industry, my country is building a low-carbon power system on the basis of the traditional power system. The system has the following basic characteristics: First, it takes ensuring energy and power security as the basic premise, meeting the power demand of economic and social development as the primary goal, and maximizing the consumption of new energy as the main task; second, it is supported by the interaction of source, grid, load and storage and multi-energy complementarity, and takes source-load interactive scheduling as an important means; third, it has the characteristics of clean, low-carbon, safe and controllable, flexible and efficient, intelligent and friendly, and open and interactive, which are different from the traditional power system. In the traditional power system, the power system scheduling is mainly the scheduling of sources, including the scheduling of thermal power, hydropower, nuclear power and other power sources. The load is rigid and generally not the object of scheduling. At this time, the scheduling concept is "source follows load"; in the low-carbon power system, the power system scheduling includes both the scheduling of sources and the scheduling of loads. The scheduling of sources includes the scheduling of thermal power, hydropower, nuclear power and other power sources, as well as the scheduling of new energy sources such as wind power and solar power generation. The load is flexible and dispatchable. The load is the object of scheduling. At this time, the scheduling concept is "source-load interaction". Therefore, the source-load interactive scheduling method in low-carbon power systems is significantly different from the traditional power system scheduling method. Research on source-load interactive scheduling methods is of great significance to ensuring the safety of low-carbon power systems and maximizing the absorption of new energy. It is a key supporting technology for promoting the low-carbonization of power systems and promoting the power industry to achieve dual carbon goals as scheduled.

The source-load interactive dispatch of low-carbon power systems needs to solve two levels of problems: first, to ensure the real-time balance of power supply and demand, that is, the sum of all power outputs and the sum of all loads in the power system should remain basically equal; second, the source-load interactive dispatch strategy can still maintain stability under random fluctuations in power or load. The former is the basic requirement of source-load interactive dispatch, ensuring that the power output can meet the power demand; the latter is the premise of source-load interactive dispatch. Any source-load interactive dispatch strategy must meet the safety requirements of the power system to ensure that the power system can operate safely and stably. The Chinese patent "A method, device and readable storage medium for optimizing active scheduling of power system (patent number ZL202011467408.1)" solves the limit distribution of new energy output and optimizes the active scheduling parameters based on the historical data of new energy output and active scheduling parameters, balances the economy and reliability of the power system, and improves the level of new energy consumption; the Chinese patent application "Massive flexible load rapid aggregation control method and device", with application publication number CN115549109A and application publication date December 30, 2022, discloses a massive flexible load rapid aggregation control method and device, and according to the characteristics of flexible loads in the power system, a centralized rapid aggregation control model of flexible loads is constructed based on data-driven fitting functions, and the optimal aggregation control strategy of flexible loads is calculated, which greatly improves the operational management efficiency of flexible resources on the load side. The above method only dispatches and controls the new energy power source or load of the power system separately, without considering the coupling effect of power scheduling and load scheduling, and does not comprehensively consider the power source and load as interactive scheduling objects, and does not consider the safety of the scheduling strategy under power fluctuations and load fluctuations. Therefore, the methods based on the above literature cannot effectively solve the source-load interactive scheduling problem of low-carbon power systems.

Summary of the invention

The purpose of the present invention is to solve the above problems existing in the prior art and to provide a method and device for source-load interactive scheduling of a low-carbon power system.

To achieve the above objectives, the present invention provides the following technical solutions:

A source-load interactive dispatching method for a low-carbon power system is divided into the following steps:

S1. Obtain the output time-varying parameter sequence _ps (t) of the power source to be dispatched from the power dispatching system, where t represents time:

_ps (t)=( _Ps (t), _Qs (t)),

P _s,min ≤P _s (t) ≤P _s,max ,

Q _s,min ≤Q _s (t) ≤Q _s,max ，

Among them, _Ps (t) is the time-varying parameter sequence of active output of the power source to be dispatched, _Qs (t) is the time-varying parameter sequence of reactive output of the power source to be dispatched, Ps _,min and Ps _,max are the minimum and maximum active output of the power source to be dispatched, respectively, and Qs _,min and Qs _,max are the minimum and maximum reactive output of the power source to be dispatched, respectively.

S2. Obtain the power time-varying parameter sequence of the dispatchable sub-loads from the power dispatching system, and construct the power time-varying parameter sequence p _l (t) of the load to be dispatched after aggregation.

S2.1. Since the load to be dispatched is composed of multiple smaller dispatchable sub-loads, the power time-varying parameter sequence of the kth dispatchable sub-load at the node where the load to be dispatched is located is first obtained from the power dispatching system.

Wherein, k is the serial number of the dispatchable sub-load, k=1,2,...,k _max , k _max is the number of dispatchable sub-loads, is the time-varying parameter sequence of active power of the kth dispatchable sub-load,/> is the reactive power time-varying parameter sequence of the kth dispatchable sub-load,/> and/> are the minimum and maximum active power of the kth dispatchable sub-load, respectively. and/> are the minimum and maximum reactive power of the kth dispatchable sub-load respectively.

S2.2. According to the power time-varying parameter sequence of the dispatchable sub-load Construct the power time-varying parameter sequence p _l (t) of the load to be dispatched after aggregation:

p _l (t) = (Px (t), Q _l (t)),

P _l,min ≤P _l (t) ≤P _l,max ,

Q _l,min ≤Q _l (t) ≤Q _l,max ，

Among them, P _l (t) is the time-varying parameter sequence of active power of the load to be scheduled, Q _l (t) is the time-varying parameter sequence of reactive power of the load to be scheduled, P _l,min and P _l,max are the minimum and maximum active power of the load to be scheduled, respectively, and Q _l,min and Q _l,max are the minimum and maximum reactive power of the load to be scheduled, respectively.

S3. According to the output time-varying parameter sequence _ps (t) of the power source to be dispatched and the power time-varying parameter sequence _pl (t) of the load to be dispatched, the power time-varying parameter sequence p(t) of the source and load to be dispatched is constructed:

p(t)＝( _ps (t), _pl (t))＝( _Ps (t), _Qs (t), _Pl (t), _Ql (t));

S4. According to the power time-varying parameter sequence p(t) of the source and load to be dispatched, the power system algebraic variable y ₀ (p(t)) corresponding to p(t) is obtained through power flow calculation, and then the power system state variable x ₀ (p(t)) corresponding to p(t) is obtained according to the power system differential algebraic equation, and then the power system operating point time-varying parameter sequence z ₀ (p(t)) is further obtained; the details are as follows:

S4.1. For a given p(t), since the active output and reactive output of the power source to be dispatched are _Ps (t) and _Qs (t) respectively, the injected power at the node where the power source to be dispatched is located is _Ps (t)+ _jQs (t), where j represents the sign of the imaginary part of the complex number; and, since the active power and reactive power of the load to be dispatched are _Pl (t) and _Ql (t) respectively, the injected power at the node where the load to be dispatched is located is -( _Pl (t)+ _jQl (t)). The injected power _Ps (t)+ _jQs (t) at the node where the power source to be dispatched is located and the injected power -( _Pl (t)+ _jQl (t)) at the node where the load to be dispatched is located are used as the initial conditions for power flow calculation, and the standard power flow calculation method is used to obtain the power system algebraic variable _y0 (p(t)) corresponding to p(t) (the standard power flow calculation method uses the Newton-Raphson power flow calculation method or the PQ decomposition power flow calculation method. For specific methods, see "Power System Analysis" (He Yangzan, Wen Zengyin, Huazhong University of Science and Technology Press, 2002).);

S4.2. According to the power system differential algebraic equation, the power system state variable x ₀ (p(t)) corresponding to p(t) is obtained.

The differential algebraic equation of the power system is:

Among them, x(t) and y(t) represent the state variable and algebraic variable of the power system respectively, both of which change with time t. represents the rate of change of the power system state variable x(t) with respect to time t, f(·,·) is the difference function relationship of the power system difference equation, and g(·,·) is the algebraic function relationship of the power system algebraic equation.

S4.3, x ₀ (p(t)) and y ₀ (p(t)) characterize the influence of p(t) on the power system state variables and algebraic variables. Therefore, the time-varying parameter sequence z ₀ (p(t)) of the power system operating point is defined as follows:

z ₀ (p(t))＝(x ₀ (p(t)),y ₀ (p(t)));

S5. Linearize the power system differential algebraic equation at the power system operating point to obtain a power system linearization model.

Linearizing the power system differential algebraic equation at the power system operating point, we get:

Where _fx (x(t),y(t)) represents the partial derivative of f(x(t),y(t)) with respect to the power system state variables, _fy (x(t),y(t)) represents the partial derivative of f(x(t),y(t)) with respect to the power system algebraic variables, Δx and Δy represent the slight increase of the power system state variables and the slight increase of the algebraic variables, respectively. represents the rate of change of the power system state variable with respect to time t, g _x (x(t), y(t)) represents the partial derivative of g(x(t), y(t)) with respect to the power system state variable, and g _y (x(t), y(t)) represents the partial derivative of g(x(t), y(t)) with respect to the power system algebraic variable.

After sorting, we get:

but Expressed as:

in, A(x(t),y(t)) represents the coefficient matrix of the power system linearization model;

Therefore, the linear model of the power system is:

S6. Construct a power system time-varying parameter system model based on the power system linearization model and the power system operation point time-varying parameter sequence z ₀ (p(t)).

According to the power time-varying parameter sequence p(t) of the source and load to be dispatched, the power system algebraic variable y ₀ (p(t)) corresponding to p(t) is obtained through power flow calculation, and then the power system state variable x ₀ (p(t)) corresponding to p(t) is obtained according to the power system differential algebraic equation, and then the power system operating point time-varying parameter sequence z ₀ (p(t)) is further obtained. Then, the power system operating point time-varying parameter sequence z ₀ (p(t)) is used as the parameterized operating point, and x ₀ (p(t)) and y ₀ (p(t)) are substituted into A(x(t), y(t)) to obtain A(x ₀ (p(t)), y ₀ (p(t))). The corresponding power system linearization model is Transformed into a power system time-varying parameter system model:

Among them, A(x ₀ (p(t)),y ₀ (p(t))) is the coefficient matrix of the power system time-varying parameter system model.

S7. Define the value range of the power time-varying parameter sequence p(t) of the source and load to be dispatched, and perform convex decomposition according to the vertices of the p(t) value space to obtain a bounded set of coefficient matrices of the power system time-varying parameter system model.

In the power time-varying parameter sequence p(t) of the source and load to be scheduled, _Ps (t), _Qs (t), _Pl (t) and _Ql (t) all have upper and lower bounds. Therefore, the value range of p(t) is a four-dimensional space. _imax is used to represent the number of vertices in the space. Then _imax = ²⁴ , each vertex is denoted as _θi , i = 1, 2, ..., _imax , and the vertex set is denoted as

Convex decomposition of p(t) yields:

Among them, α _i is the convex decomposition coefficient of p(t);

According to the convex decomposition of p(t), the coefficient matrix of the power system time-varying parameter system model is transformed into the following form:

A(x ₀ (p(t)),y ₀ (p(t)))=α ₁ A ₁ (θ ₁ )+α ₂ A ₂ (θ ₂ )+…+α _i A _i (θ _i )+…+α _imax A _imax (θ _imax ),

Among them, _Ai (θ _i ) is the coefficient submatrix corresponding to vertex θ _i ; when vertex θ _i is fixed, _Ai (θ _i ) is a constant matrix; when α _i satisfies the condition When the values of are different, the coefficient matrix A(x ₀ (p(t)),y ₀ (p(t))) of the power system time-varying parameter system model is in the vertex set/> Determined bounded concentration changes.

S8. Based on the parameter-dependent quadratic stability criterion and the linear matrix inequality, the power system is judged at the vertex set. The stability of the bounded set is determined. If the power system is stable, the power time-varying parameter sequence p(t) of the source and load to be dispatched is selected as the source-load interactive dispatch strategy of the power system.

Assume that the continuously differentiable symmetric positive definite matrix P(p(t)) has the following characteristics:

in, Respectively represent and/> The corresponding undetermined stability judgment matrices are all symmetric matrices.

in, is the derivative of p(t) with respect to time t, β _i is the convex decomposition coefficient of the derivative of p(t), μ _i is a known row vector, which is determined by the dispatching agency according to the characteristics of the power time-varying parameter sequence p(t) of the source and load to be dispatched;

The parameter-dependent quadratic stability criterion is: if there exists a symmetric matrix _Pi and a matrix G that satisfies the following matrix inequality for i values 1, 2, ..., i _max

Then the power system is at the vertex set Determined bounded centralized stability. In the parameter-dependent quadratic stability criterion, G is the undetermined auxiliary stability matrix, which is the same when i is 1, 2, ..., i _max . ^G T and/> denote the transposed matrices of G and A _i (θ _i ) respectively, P(μ _i ) denotes the i-th component of the derivative of P(p(t)) and/> The parameter-dependent quadratic stability criterion is implemented using linear matrix inequality (LMI), see the Matlab LMI toolkit for details.

The following method is used to determine whether the power time-varying parameter sequence p(t) of the source and load to be dispatched can be used as the interactive dispatch strategy of the power system source and load:

(1) If the symmetric matrix satisfies the above matrix inequality If the matrix G exists, the power system is stable under the power time-varying parameter sequence p(t) of the source and load to be dispatched. Therefore, the power time-varying parameter sequence p(t) of the source and load to be dispatched is selected as the source-load interactive dispatch strategy of the power system.

(2) If the symmetric matrix satisfies the above matrix inequality If the matrix G does not exist, the power system is unstable under the power time-varying parameter sequence p(t) of the source and load to be dispatched. Therefore, the power time-varying parameter sequence p(t) of the source and load to be dispatched cannot be used as the source-load interactive dispatch strategy of the power system.

The present invention also provides a low-carbon power system source-load interactive dispatching device based on the above method, including a time-varying parameter sequence generation module, a power system time-varying parameter system construction module, and a power system source-load interactive dispatching strategy generation module.

The time-varying parameter sequence generation module is used to obtain the output time-varying parameter sequence of the power source to be dispatched and the power time-varying parameter sequence of the load to be dispatched from the power dispatching system, and construct the power time-varying parameter sequence of the source and load to be dispatched according to the output time-varying parameter sequence of the power source to be dispatched and the power time-varying parameter sequence of the load to be dispatched; the time-varying parameter sequence generation module provides basic data for generating the power system operation point time-varying parameter sequence in the power system time-varying parameter system construction module.

The power system time-varying parameter system construction module is used to obtain the power system operating point time-varying parameter sequence through power flow calculation according to the power time-varying parameter sequence of the source and load to be dispatched and the power system differential algebraic equation; linearize the power system differential algebraic equation at the power system operating point to obtain the power system linearization model; and construct the power system time-varying parameter system model according to the power system linearization model and the power system operating point time-varying parameter sequence. The power system time-varying parameter system model provides basic data for the power system source-load interactive dispatch strategy generation module, and provides basic mathematical model support for judging whether the power time-varying parameter sequence of the source and load to be dispatched is feasible.

The power system source-load interactive dispatch strategy generation module is used to define the value range of the power time-varying parameter sequence of the source load to be dispatched, and perform convex decomposition according to the vertices of the value space to obtain the bounded set of coefficient matrices of the power system time-varying parameter system model; according to the parameter-dependent quadratic stability criterion and the linear matrix inequality, the stability of the power system in the bounded set determined by the vertex set is judged. If the power system is stable, the power time-varying parameter sequence of the source load to be dispatched is selected as the power system source-load interactive dispatch strategy, otherwise the power time-varying parameter sequence of the source load to be dispatched cannot be used as the power system source-load interactive dispatch strategy. The core of the power system source-load interactive dispatch strategy generation module is to judge the stability of the power system in the bounded set determined by the vertex set, which determines whether the power time-varying parameter sequence of the source load to be dispatched can be used as the power system source-load interactive dispatch strategy. The power system source-load interactive dispatch strategy generation module obtains the power time-varying parameter sequence of the source load to be dispatched from the time-varying parameter sequence generation module, and obtains the basic mathematical model from the power system time-varying parameter system construction module.

Each module in the above-mentioned method and device for interactive dispatching of sources and loads in a low-carbon power system can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

Compared with the prior art, the present invention has the following beneficial effects:

First, the coupling effect of power dispatch and load dispatch is taken into account, and the active output and reactive output of the power source, and the active power and reactive power of the load are used as the power time-varying parameter sequence of the source and load to be dispatched, so that the interactive dispatch of the power system source and load is time-varying and dynamic, which conforms to the characteristics of frequent fluctuations of new energy power sources and the gradual increase in the proportion of dispatchable loads in low-carbon power systems. It helps to overcome the problems of traditional dispatching of power sources or loads separately, which leads to difficulties in real-time power balance, difficulty in determining the stability of the power system, and difficulty in formulating power dispatch strategies;

Secondly, the safety of the dispatching strategy under power supply fluctuation and load fluctuation is considered, and the safety of real-time power balance and source-load fluctuation is taken as the premise and basis for formulating the source-load interactive dispatching strategy of the power system. It is proposed to determine the bounded set of coefficient matrices of the power system time-varying parameter system model according to the power time-varying parameter sequence of the source-load to be dispatched. If the power system is stable in this bounded set, the power time-varying parameter sequence of the source-load to be dispatched is selected as the source-load interactive dispatching strategy of the power system. The source-load interactive dispatching strategy formulated by this method overcomes the limitation that the traditional power system dispatching strategy is only suitable for power supply dispatching and not for source-load interactive dispatching, and provides an effective method for fully mobilizing load-side resources for real-time power balance and stable control of the power system.

Thirdly, the actual scenario of source-load interactive scheduling is taken into consideration, that is, the load to be dispatched is composed of multiple smaller dispatchable sub-loads. The power time-varying parameter sequence of the dispatchable sub-loads is obtained from the power dispatching system, and the power time-varying parameter sequence of the load to be dispatched is constructed after aggregation. This makes the proposed source-load interactive scheduling method more flexible, breaking the traditional concepts that power dispatching absolutely takes precedence over load dispatching and that dispatching smaller loads has little value for real-time power balance and stable control of the power system. It solves the problem that smaller loads are difficult to participate in source-load interactive scheduling, and provides a feasible method for smaller loads to become larger loads after aggregation and then participate in source-load interactive scheduling.

Therefore, the present invention realizes the interactive dispatching of sources and loads in low-carbon power systems, which is of great significance for maximizing the absorption of new energy, activating the adjustable capacity of the load side, and ensuring the safe and stable operation of low-carbon power systems. It can provide decision-making support and methodological support for power dispatching agencies to formulate power dispatching plans and arrange operating modes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of source-load interactive scheduling of a low-carbon power system according to the present invention;

2 is a flow chart of the source-load interactive dispatching method for a low-carbon power system according to the present invention;

3 is a structural diagram of the source-load interactive dispatching device for a low-carbon power system according to the present invention;

FIG4 is a diagram showing changes in active power flow in branches of a power system under source-load interactive dispatching in the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific implementations and drawings.

FIG1 is a schematic diagram of the interactive dispatch of sources and loads in the low-carbon power system of the present invention. G _{to be dispatched} represents the output of the power source to be dispatched, and L _{to be dispatched} represents the power of the load to be dispatched. The dispatch objects of the power dispatching agency are the power sources to be dispatched and the loads to be dispatched. The power dispatching agency ensures the real-time balance of power supply and demand and the safety of the power system by adjusting the power size of G _{to be dispatched} and L _{to be dispatched} . G _hydropower , G _{thermal power , G nuclear power} , and G _{new energy} represent the output of power sources such as hydropower, thermal power, nuclear power, and new energy, respectively, and L _{other loads} represent the power of other loads in the power system. The dispatch of these power sources and loads is the conventional dispatch of the power system, which belongs to the dispatching method of "source follows load". When formulating the dispatching plan, it is realized by reversing the power generation plan of each power source according to the power demand in different time periods. In the low-carbon power system, the dispatching agency must consider the coupling effect of G to be _dispatched and L _{to be dispatched} when dispatching the output of the power source to be dispatched G _{to be dispatched} and the power of _{the load to be dispatched} L to be dispatched, and comprehensively consider the power source and load as the interactive dispatching objects, while considering the safety of the dispatching strategy under power source fluctuations and load fluctuations. This type of power system dispatching that takes into account the impact of source-load interaction is a "source-load interaction" dispatching method, which is significantly different from traditional power system dispatching methods and is of great significance for ensuring the safety of low-carbon power systems and maximizing the absorption of new energy.

FIG2 is a flow chart of the method for interactive dispatching of low-carbon power systems in the present invention. The method is divided into the following steps:

S1. Obtain the output time-varying parameter sequence _ps (t) of the power source to be dispatched from the power dispatching system;

S2. Obtain the power time-varying parameter sequence of the dispatchable sub-loads from the power dispatching system, and construct the power time-varying parameter sequence p _l (t) of the load to be dispatched after aggregation;

S3. Construct the power time-varying parameter sequence _p (t) of the source to be dispatched according to the output time-varying parameter sequence _ps (t) of the source to be dispatched and the power time-varying parameter sequence pl(t) of the load to be dispatched;

S4, obtaining a time-varying parameter sequence of the power system operation point according to the power time-varying parameter sequence of the source and load to be dispatched and the differential algebraic equation of the power system;

S5, linearizing the power system differential algebraic equation at the power system operation point to obtain a power system linearization model;

S6. constructing a power system time-varying parameter system model according to the power system linearization model and the power system operation point time-varying parameter sequence z ₀ (p(t));

S7, defining the value range of the power time-varying parameter sequence p(t) of the source and load to be dispatched, and performing convex decomposition according to the vertices of the p(t) value space to obtain a bounded set of coefficient matrices of the power system time-varying parameter system model;

S8. Based on the parameter-dependent quadratic stability criterion and the linear matrix inequality, the power system is judged at the vertex set. The stability of the bounded set is determined. If the power system is stable, the power time-varying parameter sequence p(t) of the source and load to be dispatched is selected as the source-load interactive dispatch strategy of the power system.

Figure 3 is a structural diagram of the source-load interactive dispatching device of the low-carbon power system in the present invention. The input data of the device comes from the power dispatching system, and the original data includes the output time-varying parameter sequence of the power source to be dispatched and the power time-varying parameter sequence of the dispatchable sub-load; the output of the device is the source-load interactive dispatching strategy of the power system. The source-load interactive dispatching device of the low-carbon power system includes three modules: ① time-varying parameter sequence generation module, ② power system time-varying parameter system construction module, and ③ power system source-load interactive dispatching strategy generation module. Among them, module ① obtains raw data from the power dispatching system, generates a time-varying parameter sequence of the power system operating point, outputs it to module ②, and also generates a power time-varying parameter sequence of the source and load to be dispatched, and outputs it to module ③; module ② is responsible for constructing a power system time-varying parameter system model based on the power system linearization model and the power system operating point time-varying parameter sequence, and outputs it to module ③; module ③ obtains basic data from modules ① and ②, and is responsible for judging the stability of the power system in the bounded set determined by the vertex set based on the parameter-dependent quadratic stability criterion and the use of linear matrix inequality. On this basis, it generates a power system source-load interactive dispatching strategy based on the power time-varying parameter sequence of the source and load to be dispatched.

FIG4 is a diagram showing the change in active power flow of the power system branch under source-load interactive dispatch in the present invention. This figure is for a two-zone four-machine system commonly used in power systems, and the branch active power flow is the active power flow of the branch between nodes 7 and 8. The dispatching agency selects the generator at node 1 as the power source to be dispatched, and the load at node 7 as the load to be dispatched. The units of the output of the power source to be dispatched and the power of the load to be dispatched are both per unit. To simplify the analysis and facilitate explanation, the output time-varying parameter sequence p _s (t) of the power source to be dispatched is divided into two sections: when the time is 0≤t≤10s, the active output and reactive output of the power source to be dispatched are 7 and 1.4801, respectively; when the time is t≥10s, the active output and reactive output of the power source to be dispatched are 6.95 and 1.4741, respectively. The power time-varying parameter sequence p _l (t) of the load to be dispatched is divided into two sections: when the time is 0≤t≤10s, the active power and reactive power of the load to be dispatched are 9.67 and -1 respectively; when the time is t≥10s, the active power and reactive power of the load to be dispatched are 9.57 and -0.95 respectively. Correspondingly, the power system operation point is divided into two sections: when the time is 0≤t≤10s, the power system operation point is determined by the injection power of 7+1.4801j at the node where the power source to be dispatched is located and the injection power of -9.67+j at the node where the load to be dispatched is located; when the time is t≥10s, the power system operation point is determined by the injection power of 6.95+1.4741j at the node where the power source to be dispatched is located and the injection power of -9.57+0.95j at the node where the load to be dispatched is located. The Matlab LMI toolkit is used to implement the parameter-dependent secondary stability criterion in the source-load interactive dispatch method of the low-carbon power system, and the power time-varying parameter sequence of the source-load to be dispatched is set to the corresponding two segments, namely p(t) = ( _ps (t), _pl (t)), and it is concluded that the power system is stable under this p(t). This p(t) is selected as the source-load interactive dispatch strategy of the power system. Figure 4 shows the branch active power flow change diagram of node 7-node 8 of the power system under this p(t). The figure shows that after the output of the power source to be dispatched and the power of the load to be dispatched change at t = 10s, the branch power flow of node 7-node 8 can still maintain stability, which also shows that the source-load interactive dispatch strategy of the power system is effective.

Claims (6)

1. The method for source load interactive scheduling of the low-carbon power system is characterized by comprising the following steps of:

S1, acquiring an output time-varying parameter sequence p _s (t) of a power supply to be scheduled from a power scheduling system, wherein t represents time:

p_s(t)＝(P_s(t),Q_s(t))，

P_s,min≤P_s(t)≤P_s,max，

Q_s,min≤Q_s(t)≤Q_s,max，

Wherein P _s (t) is an active power output time-varying parameter sequence of the power supply to be scheduled, Q _s (t) is a reactive power output time-varying parameter sequence of the power supply to be scheduled, P _s,min and P _s,max are respectively an active power output minimum value and a reactive power output maximum value of the power supply to be scheduled, and Q _s,min and Q _s,max are respectively a reactive power output minimum value and a reactive power output maximum value of the power supply to be scheduled;

S2, acquiring a power time-varying parameter sequence of a schedulable sub-load from a power scheduling system, and constructing a power time-varying parameter sequence p _l (t) of a load to be scheduled after aggregation

S2.1, because the load to be scheduled is formed by aggregating a plurality of schedulable sub-loads with smaller scale, firstly, the power time-varying parameter sequence of the kth schedulable sub-load at the node where the load to be scheduled is located is obtained from the power scheduling system

Where k is the number of schedulable sub-loads, k=1, 2, …, k _max,k_max is the number of schedulable sub-loads,Active power time-varying parameter sequence for kth schedulable sub-load,/>Reactive power time-varying parameter sequence for kth schedulable sub-load,/>And/>Active power minimum and maximum for kth schedulable sub-load, respectively,/>And/>Reactive power minimum and maximum values for the kth schedulable sub-load, respectively;

S2.2, according to the power time-varying parameter sequence of the schedulable sub-load Constructing a power time-varying parameter sequence p _l (t) of the load to be scheduled after aggregation:

p_l(t)＝(P_l(t),Q_l(t))，

P_l,min≤P_l(t)≤P_l,max，

Q_l,min≤Q_l(t)≤Q_l,max，

Wherein P _l (t) is an active power time-varying parameter sequence of a load to be scheduled, Q _l (t) is a reactive power time-varying parameter sequence of the load to be scheduled, P _l,min and P _l,max are respectively an active power minimum value and a reactive power maximum value of the load to be scheduled, and Q _l,min and Q _l,max are respectively a reactive power minimum value and a reactive power maximum value of the load to be scheduled;

S3, constructing a power time-varying parameter sequence p (t) of the source load to be scheduled according to the power-out time-varying parameter sequence p _s (t) of the power source to be scheduled and the power time-varying parameter sequence p _l (t) of the load to be scheduled:

p(t)＝(p_s(t),p_l(t))＝(P_s(t),Q_s(t),P_l(t),Q_l(t))；

S4, according to a power time-varying parameter sequence p (t) of a source load to be scheduled, obtaining a power system algebraic variable y ₀ (p (t)) corresponding to the p (t) through power flow calculation, and then obtaining a power system state variable x ₀ (p (t)) corresponding to the p (t) according to a power system differential algebraic equation, and further obtaining a power system operation working point time-varying parameter sequence z ₀ (p (t)); the method comprises the following steps:

s4.1, for a given P (t), as the active output and the reactive output of the power supply to be scheduled are P _s (t) and Q _s (t) respectively, the injection power at the node where the power supply to be scheduled is located is P _s(t)+jQ_s (t), and j represents the imaginary symbol of a complex number; and, because the active power and reactive power of the load to be scheduled are P _l (t) and Q _l (t), respectively, the injection power at the node where the load to be scheduled is located is- (P _l(t)+jQ_l (t)); taking the injection power P _s(t)+jQ_s (t) at the node where the power supply to be scheduled is located and the injection power- (P _l(t)+jQ_l (t)) at the node where the load to be scheduled is located as the initial condition of power flow calculation, and obtaining the algebraic variable y ₀ (P (t)) of the power system corresponding to P (t) by adopting a standard power flow calculation method;

S4.2, obtaining a power system state variable x ₀ (p (t)) corresponding to p (t) according to a power system differential algebraic equation

The differential algebraic equation of the power system is:

Wherein x (t) and y (t) respectively represent a state variable and an algebraic variable of the power system, both of which change with time t, The change rate of the state variable x (t) of the power system to the time t is represented, f (·, ·) is the differential function relation of the differential equation of the power system, and g (·, ·) is the algebraic function relation of the algebraic equation of the power system;

S4.3, x ₀ (p (t)) and y ₀ (p (t)) characterize the influence of p (t) on the power system state variables and algebraic variables, so the power system operating point time-varying parameter sequence z ₀ (p (t)) is defined as follows:

z₀(p(t))＝(x₀(p(t)),y₀(p(t)))；

s5, linearizing the differential algebraic equation of the power system at the operation working point of the power system to obtain a linearization model of the power system

Linearizing a differential algebraic equation of the power system at a power system operation working point to obtain:

wherein f _x (x (t), y (t)) represents the partial derivative of f (x (t), y (t)) with respect to the power system state variable, f _y (x (t), y (t)) represents the partial derivative of f (x (t), y (t)) with respect to the power system algebraic variable, Δx and Δy represent the power system state variable and algebraic variable microincreases, respectively, Representing the rate of change of the power system state variable with respect to time t, g _x (x (t), y (t)) representing the partial derivative of g (x (t), y (t)) with respect to the power system state variable, g _y (x (t), y (t)) representing the partial derivative of g (x (t), y (t)) with respect to the power system algebraic variable;

after finishing, the following steps are obtained:

Then Expressed as:

wherein, A (x (t), y (t)) represents a coefficient matrix of a linearization model of the power system;

thus, the power system linearization model is:

S6, constructing a time-varying parameter system model of the power system according to the linearization model of the power system and a time-varying parameter sequence z ₀ (p (t)) of the operating point of the power system

According to a power time-varying parameter sequence p (t) of a source load to be scheduled, obtaining a power system algebraic variable y ₀ (p (t)) corresponding to p (t) through power flow calculation, obtaining a power system state variable x ₀ (p (t)) corresponding to p (t) according to a power system differential algebraic equation, further obtaining a power system operation working point time-varying parameter sequence z ₀ (p (t)), taking the power system operation working point time-varying parameter sequence z ₀ (p (t)) as a parameterized working point, substituting x ₀ (p (t)) and y ₀ (p (t)) into A (x (t), y (t)) to obtain A (x ₀(p(t)),y₀ (p (t)) and obtaining a corresponding power system linearization modelThe method comprises the steps of converting into a time-varying parameter system model of the power system:

Wherein A (x ₀(p(t)),y₀ (p (t))) is a coefficient matrix of a time-varying parameter system model of the power system;

S7, defining a power time-varying parameter sequence p (t) value range of the source load to be scheduled, and performing convex decomposition according to the p (t) value space vertex to obtain a coefficient matrix bounded set of a power system time-varying parameter system model

P _s(t),Q_s(t),P_l (t) and Q _l (t) in the power time-varying parameter sequence P (t) of the source load to be scheduled have an upper bound and a lower bound, so that the value range of P (t) is a four-dimensional space, i _max is adopted to represent the number of vertexes of the space, i _max＝2⁴ is adopted, each vertex is marked as theta _i,i＝1,2,…,i_max, and a vertex set is marked as theta _i,i＝1,2,…,i_max

And (3) carrying out convex decomposition on p (t) to obtain:

Wherein, alpha _i is p (t) convex decomposition coefficient;

according to p (t) convex decomposition, the coefficient matrix of the power system time-varying parameter system model is converted into the following form:

Wherein, a _i(θ_i) is a coefficient submatrix corresponding to vertex θ _i; when the vertex theta _i is fixed, A _i(θ_i) is a constant matrix; when alpha _i is satisfied The coefficient matrix A (x ₀(p(t)),y₀ (p (t))) of the power system time-varying parametric system model is found at the vertex set/>The determined bounded set of changes;

s8, depending on the secondary stability criterion according to the parameters, judging the vertex set of the power system If the power system is stable, the power time-varying parameter sequence p (t) of the source load to be scheduled is selected as a power system source load interaction scheduling strategy

Let the continuously microsymmetric positive definite matrix P (t)) have the following characteristics:

wherein, Respectively express and/>The corresponding stability matrix to be determined is a symmetric matrix;

wherein, For the derivative of p (t) with respect to time t, β _i is the convex decomposition coefficient of the p (t) derivative, μ _i is the known row vector;

The parameter dependent secondary stability criterion is: the following matrix inequality is satisfied if both the symmetry matrix P _i and the matrix G take the values 1,2, …, i _max for i:

The power system is at the vertex set The determined bounded concentration is stable; in the parameter dependent secondary stability criterion, G is a pending auxiliary stability matrix, and when i is 1,2, … and i _max, G ^T and/>, the values are the sameRespectively represent G and/>P (mu _i) represents the ith component of the derivative of P (t)) and/>Is a product of (2);

The method comprises the following steps of determining whether a power time-varying parameter sequence p (t) of a source load to be scheduled can be used as a source load interactive scheduling strategy of a power system:

(1) Symmetric matrix if the matrix inequality described above is satisfied And the matrix G exists, the power system is stable under the power time-varying parameter sequence p (t) of the source load to be scheduled, so that the power time-varying parameter sequence p (t) of the source load to be scheduled is selected as a power system source load interactive scheduling strategy;

(2) Symmetric matrix if the matrix inequality described above is satisfied And if the matrix G does not exist, the power system is unstable under the power time-varying parameter sequence p (t) of the source load to be scheduled, so that the power time-varying parameter sequence p (t) of the source load to be scheduled cannot be used as a power system source load interactive scheduling strategy.

2. A method for source load interactive scheduling of a low-carbon power system according to claim 1, which is characterized in that: the known row vector mu _i is determined by the scheduling mechanism based on the characteristics of the power time-varying parameter sequence p (t) of the source load to be scheduled.

3. A method for source load interactive scheduling of a low-carbon power system according to claim 1, which is characterized in that: the parameter dependent quadratic stabilization criterion is implemented using a linear matrix inequality.

4. A low-carbon power system source load interactive scheduling device based on the method of any one of claims 1 to 3, characterized in that: the device comprises a time-varying parameter sequence generation module, a power system time-varying parameter system construction module and a power system source load interaction scheduling strategy generation module;

The time-varying parameter sequence generation module is used for acquiring an output time-varying parameter sequence of the power supply to be scheduled and a power time-varying parameter sequence of the load to be scheduled from the power scheduling system, and constructing a power time-varying parameter sequence of the power load to be scheduled according to the output time-varying parameter sequence of the power supply to be scheduled and the power time-varying parameter sequence of the load to be scheduled; the time-varying parameter sequence generation module provides basic data for generating a time-varying parameter sequence of an operation working point of the power system in the power system time-varying parameter system construction module;

The power system time-varying parameter system construction module is used for obtaining a power system operation working point time-varying parameter sequence through power flow calculation according to a power time-varying parameter sequence of a source load to be scheduled and a power system differential algebraic equation; linearizing a differential algebraic equation of the power system at an operating working point of the power system to obtain a linearization model of the power system; constructing a time-varying parameter system model of the power system according to the linearization model of the power system and the time-varying parameter sequence of the operating working point of the power system; the power system time-varying parameter system model provides basic data for a power system source load interaction scheduling strategy generation module, and provides basic mathematical model support for judging whether a power time-varying parameter sequence of a source load to be scheduled is feasible or not;

The power system source load interactive scheduling strategy generation module is used for defining a power time-varying parameter sequence value range of a source load to be scheduled, and performing convex decomposition according to the value space vertexes to obtain a coefficient matrix bounded set of a power system time-varying parameter system model; judging the stability of the power system in the bounded set determined by the vertex set according to the parameter dependence secondary stability criterion and by adopting a linear matrix inequality, if the power system is stable, selecting a power time-varying parameter sequence of the source load to be scheduled as a power system source load interactive scheduling strategy, otherwise, the power time-varying parameter sequence of the source load to be scheduled cannot be used as the power system source load interactive scheduling strategy; the core of the power system source load interaction scheduling strategy generation module is to judge the stability of the power system in a bounded set determined by a vertex set, and determine whether a power time-varying parameter sequence of a source load to be scheduled can be used as the power system source load interaction scheduling strategy; the power system source load interactive scheduling strategy generation module acquires a power time-varying parameter sequence of a source load to be scheduled from the time-varying parameter sequence generation module, and acquires a basic mathematical model from the power system time-varying parameter system construction module.

5. The low-carbon power system source load interactive scheduling device according to claim 4, wherein: the various modules in the apparatus may be implemented in whole or in part by software, hardware, and combinations thereof.

6. The low-carbon power system source load interactive scheduling device according to claim 4, wherein: the modules in the device can be embedded in hardware or independent of a processor in the computer equipment, and can also be stored in a memory in the computer equipment in a software mode, so that the processor can call and execute the operations corresponding to the modules.