Comprehensive energy system operation evaluation method and device based on security boundary

Abstract

The invention discloses an integrated energy system operation evaluation method and device based on a safety boundary, and belongs to the field of energy system dispatching operation. The method comprises the following steps: establishing a system safety model taking line reference safety and equipment reference safety of an energy system as constraints according to probability power of renewable energy sources; wherein the system security model comprises all working points which operate safely under the constraint of the reference security check; sequentially establishing a safety boundary model and a safety distance model of the integrated energy system according to the simplified system safety model, and establishing a dimension reduction observation model of the integrated energy system according to the maximum energy supply capability of the system; and solving the dimension reduction observation model to obtain boundary data used for evaluating whether the integrated energy system is in a safe operation state or not. According to the invention, the safety assessment accuracy of the comprehensive energy system containing renewable energy sources can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy system dispatching and operation, and particularly relates to a method and device for evaluating the operation of an integrated energy system based on a safety boundary. Background Art

[0002] With the proposal of the global carbon neutrality goal, integrated energy systems containing renewable energy are developing rapidly and being widely applied. Safe operation is the research foundation for aspects such as the optimal control of integrated energy systems and participation in energy market transactions. However, the coupling effect among various energies in the integrated energy system enables any local disturbance to be transmitted to the entire system. This leads to the fact that after renewable energy is connected to the integrated energy system, the uncertainty of its output seriously affects the energy supply-demand balance of the system, and further makes the safe operation of the system face higher requirements.

[0003] In related technologies, the evaluation of the safety of integrated energy systems usually adopts the point-by-point method. This method evaluates the safety of local operating points and lacks the ability to evaluate the safety area of the overall system, resulting in inaccurate evaluation results of the safety of integrated energy systems and further making it difficult for the system to maintain a safe and stable operating state.

[0004] Based on this, there is an urgent need for a method and device for evaluating the operation of an integrated energy system based on a safety boundary to solve the above technical problems. Summary of the Invention

[0005] The present invention provides a method and device for evaluating the operation of an integrated energy system based on a safety boundary, which can solve the problem of inaccurate evaluation results of the safety of integrated energy systems in related technologies. The technical solutions are as follows:

[0006] On the one hand, a method for evaluating the operation of an integrated energy system based on a safety boundary is provided. The method includes:

[0007] Establish a system safety model with the line reference safety and equipment reference safety of the energy system as constraints according to the probabilistic power of renewable energy; wherein, the system safety model includes all working points that operate safely under the constraints of reference safety inspection.

[0008] Establish a safety boundary model and a safety distance model of the integrated energy system in sequence according to the simplified system safety model, and establish a reduced-dimensional observation model of the integrated energy system according to the maximum energy supply capacity of the system.

[0009] Solve the reduced-dimensional observation model to obtain boundary data for evaluating whether the integrated energy system is in a safe operating state.

[0010] On the other hand, a device for evaluating the operation of an integrated energy system based on a safety boundary is provided. The device includes:

[0011] A first modeling module is configured to establish a system security model based on the probabilistic power of renewable energy, with the line reference safety and equipment reference safety of the energy system as constraints; wherein, the system security model includes all operating points that operate safely under the reference safety inspection constraints.

[0012] A second modeling module is configured to sequentially establish a safety boundary model and a safety distance model of the integrated energy system based on the simplified system security model, and establish a reduced-dimension observation model of the integrated energy system according to the maximum energy supply capacity of the system.

[0013] A calculation module is configured to solve the reduced-dimension observation model to obtain boundary data for evaluating whether the integrated energy system is in a safe operating state.

[0014] On the other hand, a computer device is provided, which includes a memory and a processor. The memory is used to store a computer program, and the processor is used to execute the computer program stored on the memory to implement the steps of the above-mentioned method for evaluating the operation of an integrated energy system based on a safety boundary.

[0015] On the other hand, a computer-readable storage medium is provided. The storage medium stores a computer program, and when the computer program is executed by a processor, it implements the steps of the above-mentioned method for evaluating the operation of an integrated energy system based on a safety boundary.

[0016] On the other hand, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, it implements the steps of the above-mentioned method for evaluating the operation of an integrated energy system based on a safety boundary.

[0017] The technical solution provided by the present invention can at least bring the following beneficial effects: First, a safety model of the integrated energy system considering the reference safety constraints of the system's key equipment and lines is established based on the special source-load mismatch fault caused by the imbalance between energy supply and demand due to the uncertainty of renewable energy. Then, according to the actual engineering requirements, a simplified method for quantifying the safety boundary, distance, and supply capacity is proposed. On this basis, a reduced-dimension observation method based on the optimization of observation variables is proposed to expand the safe area not affected by the uncertainty of renewable energy. This method can be used to analyze the impact of the uncertainty of renewable energy on the safe area, which helps to implement subsequent safety control measures for the integrated energy system. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 is a flowchart of a method for evaluating the operation of an integrated energy system based on a security boundary provided by an embodiment of the present invention;

[0020] Figure 2 is a schematic structural diagram of an integrated energy system provided by an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of the evolution process of a two-dimensional security domain based on (L8, L9) provided by an embodiment of the present invention;

[0022] Figure 4 is a comparison diagram of the upper and lower boundaries of a simplified security model and a non-simplified security model provided by an embodiment of the present invention;

[0023] Figure 5 is a schematic diagram of the ABC-FED security region with L1, L2, and L9 as observation variables provided by an embodiment of the present invention;

[0024] Figure 6 is a structural diagram of a device for evaluating the operation of an integrated energy system based on a security boundary provided by an embodiment of the present invention;

[0025] Figure 7 is a hardware architecture diagram of a computer device provided by an embodiment of the present invention. Detailed implementation manners

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0027] As mentioned above, the integrated energy system is conducive to achieving a low-carbon transformation of the energy structure and efficient utilization of energy. However, in related technologies, there is little research on the impact of the uncertainty of renewable energy on the safe operation boundary of the integrated energy system.

[0028] Based on this, the concept of the present invention lies in establishing a comprehensive energy system security model considering the reference security constraints of key equipment and lines in the system, and realizing the evaluation of the operation security of the comprehensive energy system through dimensionality reduction observation.

[0029] The following describes the specific implementation manners of the above concept.

[0030] Please refer to Figure 1 , a method for evaluating the operation of a comprehensive energy system based on a security boundary provided by an embodiment of the present invention, the method comprising:

[0031] Step 100, establishing a system security model with the reference security of lines and equipment of the energy system as constraints according to the probabilistic power of renewable energy; wherein, the system security model contains all operating points that operate safely under the constraints of reference security inspection.

[0032] Step 102, successively establishing a security boundary model and a security distance model of the comprehensive energy system according to the simplified system security model, and establishing a dimensionality reduction observation model of the comprehensive energy system according to the maximum energy supply capacity of the system.

[0033] Step 104, solving the dimensionality reduction observation model to obtain boundary data for evaluating whether the comprehensive energy system is in a safe operating state.

[0034] In an embodiment of the present invention, according to the energy supply-demand imbalance caused by the uncertainty of renewable energy as a special source-load mismatch fault, a comprehensive energy system security model considering the reference security constraints of key equipment and lines in the system is established. Then, according to the actual engineering requirements, a simplified method for quantifying the security boundary, distance, and supply capacity is proposed. On this basis, a dimensionality reduction observation method based on the optimization of observation variables is proposed to expand the safe area not affected by the uncertainty of renewable energy. This method can be used to analyze the impact of the uncertainty of renewable energy on the safe area, and is helpful for subsequent implementation of the security control measures of the comprehensive energy system.

[0035] The following describes Figure 1 the execution manners of each step shown in

[0036] First, for step 100, a system security model with the reference security of lines and equipment of the energy system as constraints is established according to the probabilistic power of renewable energy.

[0037] In an embodiment of the present invention, the comprehensive energy system containing renewable energy is composed of a distribution network, a heat network, a gas source, an energy hub, and end loads, as shown in Figure 2As shown in the figure, to improve the safety and reliability of the integrated energy system in energy supply, the power grids in different regions are interconnected through tie switches, and the heat networks are interconnected through multiple sources through lines. The energy hub (EH) includes a power supply area and a multi-energy complementary area. The power supply area consists of a transformer (T) and a power feeder; the multi-energy complementary area consists of a gas boiler (GB), a combined heat and power (CHP), an electric boiler (EB), an electric energy storage (EES), a heat energy storage (HES), a circulation pump (CP), a power feeder, and a heat pipeline. Therefore, as the energy supply link of the integrated energy system, the energy hub is the focus of the safety boundary modeling and observation of the integrated energy system in the present invention.

[0038] In this embodiment, the definition of the accident set includes, on the one hand, the outage of the energy hub line outlet and equipment, and on the other hand, the energy supply and demand imbalance caused by the uncertainty of renewable energy. In addition, the definition of the safe area of the integrated energy system is the set of safe operating working points under the constraint of the benchmark safety inspection. Given the observability of the load at the energy hub line outlet, it is selected as the working point.

[0039] In the embodiment of the present invention, the system safety model is determined through the following steps: according to the probability power, the line energy supply change function and the equipment energy supply change function of the integrated energy system are respectively determined; according to the access mode of the renewable energy and the integrated energy system, the line energy supply change function is solved, and the upper and lower limits of the line benchmark safety constraint and the upper and lower limits of the equipment benchmark safety constraint are respectively calculated, and the system safety model is established according to the calculation results.

[0040] Due to the uncertainty of the output of renewable resources, the embodiment of the present invention defines the probability power Cpro to characterize the renewable energy power generation power corresponding to the environmental parameters on the time section, and the probability power is determined according to the actual power of the renewable energy.

[0041] Specifically, first, based on the two-parameter Weibull distribution model, the fan power output equation is determined:

[0042]

[0043]

[0044] In the formula: f(V h ) is the wind speed probability density function; c w is the scale variable of f(V h ); k w is the shape variable of f(V h ); V h is the actual wind speed; V in is the cut-in wind speed; V r is the wind speed rated value; V out is the cut-out wind speed; PWT is the fan power; C WT is the rated value 1 of the fan power.

[0045] Next, based on the beta distribution model, determine the photovoltaic power output power equation:

[0046]

[0047] In the formula: f(S h ) is the probability density function of the light intensity; α p is the scale variable of f(S h ); β p is the shape variable of f(S h ); S h is the actual light intensity; S r is the rated value of the light intensity; P PV is the photovoltaic power; C PV is the rated value of the photovoltaic power.

[0048] As can be seen from the above two equations, the probability characteristics of the light intensity and wind speed result in the random variation of the actual power of the photovoltaic and the fan between zero and the rated power. Therefore, the probabilistic power of renewable energy devices represented by photovoltaic and fan has definite upper and lower limits:

[0049]

[0050] In the formula, C pro is the probabilistic power; and C pro are the upper and lower limits of C pro respectively; C RE is the rated power of the renewable energy device.

[0051] Adding the probabilistic power of the renewable energy device to the line benchmark safety constraint of the energy system, the line power supply change function can be obtained:

[0052] L lmn,shift +L n ≤C ln +C pro =[C ln ,C ln +C RE

[0053] In the formula: L lmn,shift is the load transferred from line n after line m fails and is out of service; L n is the original load of line n; C ln is the rated value of the capacity of line n;

[0054] ​Adding the probabilistic power of renewable energy equipment to the equipment benchmark safety constraints of the energy system, the equipment energy supply change function can be obtained:

[0055] H hij,shift +H j ≤C hj +C pro =[C hj ,C hj +C RE

[0056] In the formula, H hij,shift is the load transferred by equipment j after equipment i fails and shuts down; H j is the original load of equipment j; C hj is the rated value of the power of equipment j.

[0057] Furthermore, the modes of renewable energy accessing the integrated energy system are divided into two types: distributed access and centralized access. In the distributed access mode, the renewable energy equipment accesses the distribution network line in a T-shaped structure, as shown by RE Figure 2 in dis . For the time being, factors such as RE cen , PV1, PV2, PV3, and WT are not considered. In the centralized access mode, the renewable energy equipment accesses the low-voltage side of the transformer in the energy hub in a T-shaped structure, as shown by RE Figure 2 in cen . For the time being, factors such as RE dis , PV1, PV2, PV3, and WT are not considered. Different access modes result in different corresponding benchmark safety constraints after the system key components fail and shut down.

[0058] First, calculate the upper and lower limits of the line benchmark safety constraints:

[0059] When the renewable energy accesses the integrated energy system in a distributed manner, the first constraint upper limit of the line benchmark safety constraint is:

[0060]

[0061] Taking Figure 2 as an example, when line l5 fails and shuts down, load L5 and L6 need to be supplied jointly by line l6, renewable energy equipment RE dis , and electrical energy storage EES. Thus, we can obtain:

[0062]

[0063] In the formula, C EES is the rated charge and discharge power of the electrical energy storage, with discharge greater than 0 and charge less than 0; and are respectively​ Upper and lower bounds; n RE is the number of renewable energy devices.

[0064] When the renewable energy adopts centralized access to the integrated energy system, the second constraint upper limit of the line reference safety constraint is:

[0065]

[0066] Take Figure 2 as an example. When line l5 fails and shuts down, it is necessary for line l6 and the electrical energy storage EES to jointly supply loads L5 and L6. In order to use a unified interval expression corresponding to the distributed access, a point is represented by an interval, that is, the upper and lower limits of the interval are the same. Thus, we can get:

[0067]

[0068] In the formula, and are respectively the upper and lower bounds.

[0069] To prevent affecting the stable operation of the system, the present invention also adds the reverse power transmission of the renewable energy power generation equipment to the transformer to the defined accident set. When the renewable energy equipment adopts distributed or centralized access to the integrated energy system, the lower limit of the line reference safety constraint is:

[0070]

[0071] In the formula, P con is the power consumption of the electrical equipment.

[0072] Take Figure 2 as an example. If line l6 shuts down due to the above failure, it is necessary for line l5 to rebalance the power supply and demand of the system and satisfy the following constraints:

[0073] L5 + L6 ≥ n RE C pro + C EES

[0074] At the same time, after the load transfer, it is still necessary to meet the energy consumption of the electric drive equipment under normal conditions, that is:

[0075] L5 ≥ P con

[0076] In the formula, n RE = 1 indicates that the integrated energy system adopts centralized access to renewable energy equipment.

[0077] The corresponding lower constraint limit is:

[0078]

[0079] In the formula, and are respectively the upper and lower bounds.

[0080] Next, calculate the upper and lower limits of the equipment benchmark safety constraint:

[0081] When the renewable energy adopts distributed access to the integrated energy system, the first constraint upper limit of the equipment benchmark safety constraint is:

[0082]

[0083] In the formula, H T and H CHP are respectively the loads supplied by the transformer and the combined heat and power unit; C CHP is the rated power of the combined heat and power unit; c u is the upper limit of the heat - to - electricity ratio coefficient of the combined heat and power unit; C HES1 is the rated heat storage / discharge power of the heat energy storage HES1, with heat discharge greater than 0 and heat storage less than 0;

[0084] Taking Figure 2 as an example, when the No. 1 transformer fails and stops operating, the energy supply of H T1 and H CHP needs to be jointly satisfied by the combined heat and power unit, the electrical energy storage, and the renewable energy RE dis :

[0085]

[0086] Further considering the output constraint of the combined heat and power unit, we can obtain:

[0087]

[0088] In the formula, and are respectively the upper and lower bounds.

[0089] When the renewable energy adopts centralized access to the integrated energy system, the second constraint upper limit of the equipment benchmark safety constraint is:

[0090]

[0091] Taking Figure 2 as an example, when the No. 1 transformer fails and stops operating, the energy supply of H T1 and H CHP needs to be jointly satisfied by the combined heat and power unit, the electrical energy storage, and the renewable energy RE cen :

[0092]

[0093] In the formula, and are respectively the upper and lower bounds.

[0094] When the renewable energy equipment adopts distributed or centralized access to the integrated energy system, the lower limit C of the equipment benchmark safety constraint RE,equ is:

[0095] H T + H CHP ≥ max(H T + P con , c m (L n - C HES1 ) + C EES + n RE C pro ) = C RE,equ

[0096] Taking Figure 2 as an example, when the No. 1 transformer fails and shuts down, the cogeneration unit needs to re - balance the energy supply and demand of the system to meet the constraint equation:

[0097] H T1 + H CHP ≥ c m (L2 - C HES1 ) + C EES + n RE C pro

[0098] In the formula, c m is the heat - electricity ratio of the cogeneration unit; n RE = 1 indicates that the integrated energy system adopts centralized access to renewable energy equipment.

[0099] The corresponding lower limit of the equipment benchmark safety constraint:

[0100] H T1 + H CHP ≥ max(H T1 + P con , c m (L2 - C HES1 ) + C EES + n RE C pro ) = C RE,equ

[0101]

[0102] CRE,equ = max(H T1 + P con , c m (L2 - C HES1 ) + C EES )

[0103]

[0104] Wherein, and C RE,equ are the upper and lower bounds of C RE,equ respectively.

[0105] After determining the upper and lower limits of the benchmark safety constraints of the lines and equipment, the security model of the integrated energy system considering the probabilistic power of renewable energy equipment can be expressed as:

[0106]

[0107] Where: Ω IES-SR is the security region of the integrated energy system; L is the working point vector; C pro is the vector of probabilistic power, with randomness characteristics; is the system security region corresponding to the probabilistic power; Ψ is the set of probabilistic power; M is the number of lines; h(L) = 0 is the multi - energy flow balance constraint; G min ≤ G(L) ≤ G max is the energy network constraint; and are the column matrices of the upper and lower limits of the energy supply capacity of the d - th row respectively; λ l , λ u are the line parameters corresponding to the upper and lower limits of the benchmark safety constraints respectively.

[0108] For step 102, based on the simplified system security model, the security boundary model and the security distance model of the integrated energy system are established successively, and according to the maximum energy supply capacity of the system, the reduced - dimension observation model of the integrated energy system is established.

[0109] For the convenience of subsequent calculation and processing, it is necessary to simplify the system security model established in step 100, and the specific process is as follows:

[0110] As can be seen from the above model, Ω IES-SR is composed of all unions, and the working points within the security domain of the integrated energy system containing renewable energy are probabilistically safe. The set of working points that satisfy the benchmark safety constraints under any probabilistic power of renewable energy is defined as the region Ω IES-USR that cannot be affected by the uncertainty of renewable energy, which is composed of all intersections. Therefore, to ensure the safe operation of the integrated energy system, the working points should be located in ΩIES-USR area

[0111] Then, based on the interval inequality solving method, the benchmark safety constraint in the above formula can be rewritten as:

[0112]

[0113] In the formula, and are respectively the column matrices of the upper and lower limits of the energy supply capacity of the d-th row; and are respectively the interval values of the upper and lower limits of the energy supply capacity.

[0114] According to the above two formulas, the mathematical expressions of Ω IES-SR and Ω IES-USR can be deduced as follows:

[0115]

[0116] Let C pro =(0,…,0…,0) and corresponding are respectively defined as and Then

[0117] Next, combined with the actual engineering needs, the following simplified safety model can be obtained:

[0118]

[0119] According to the simplified safety model, the safety boundary model corresponding to line m is:

[0120]

[0121] Among them:

[0122]

[0123] λ k is the line parameter; are respectively the upper and lower safety boundaries of Ω IES-SR corresponding to line m; are respectively and upper limits, corresponding to are respectively and lower limits, corresponding to

[0124] Taking the No. 3 transformer and No. 4 transformer in Figure 2 as an example, let Cl8 = C l9 > C T4 >(C T3 + C PV2 + C WT ) = (C T3 + C RE ), where C l8 and C l9 represent the rated capacities of lines L8 and L9 respectively; C T3 and C T4 represent the rated powers of transformer No. 3 and transformer No. 4 respectively. Then, the schematic diagram of the two-dimensional safety region based on (L8, L9) is as shown in Figure 3 (a). When C pro varies from C pro = (0,…,0…, 0) to , the boundary of the two-dimensional safety region moves from Figure 3 (b) to Figure 3 (c), and finally evolves into Figure 3 (d).

[0125] Then, according to the safety boundary model, a safety distance model is established to characterize the vertical distance from the operating point m' to .

[0126]

[0127] where

[0128]

[0129] is the load of line k in the operating point m'; are the distances from the operating point m' to respectively; are the upper and lower limits of respectively; are the upper and lower limits of respectively.

[0130] To quickly solve the above model, a dimensionality reduction observation model considering the system function ability needs to be established. The maximum energy supply ability of the integrated energy system is calculated by the following formula:

[0131]

[0132] In the formula, T ITSC is the energy supply ability; T ITSC are the upper and lower bounds of the maximum load demand that the system can satisfy, that is, the ITSC operating point. For the convenience of solution, the above formula can be transformed into a deterministic optimization model:

[0133]

[0134] Further, based on the ITSC operating point, the observed variable is selected as t obs loads of the lines, and through the solution of the simplified safety boundary, the dimensionality reduction projection of the safety domain of the integrated energy system in the t obs dimensional space can be realized, where 0 < t obs ≤M. To improve the reliability of the safe operation of the integrated energy system, it is necessary to optimize the observed variables to maximize Ω after dimensionality reduction IES-USR . Represent the dimensionality reduction observation model of Ω IES-USR :

[0135]

[0136] Λ = {e|e ∈ {b1×1,…,b i ×i,…,b M ×M}, e ≠ 0}

[0137] L obs = {L m |m ∈ Λ}

[0138] In the formula, F DRO is the dimensionality reduction observation function; is the ITSC corresponding to T minimum value; L obs is the set of optimized observed variables; Λ is the line set of the optimized observed variables; b i is a 0-1 variable, and b i = 1 indicates that line i is an observed variable.

[0139] For step 104, solve the dimensionality reduction observation model to obtain boundary data for evaluating whether the integrated energy system is in a safe operating state.

[0140] In the embodiment of the present invention, the solution process specifically includes:

[0141] Initialize the ITSC operating point and obtain and T ITSC by solving the above deterministic optimization equation, and obtain the line outlet load corresponding to the ITSC operating point;

[0142] Then initialize the line set Λ and solve the following observation variable optimization selection model of the thermal or gas system:

[0143] maxF DRO

[0144]

[0145] Where: X is the set of lines in the thermal or gas system; k loop is the total number of lines in the thermal and gas systems;

[0146] The optimized set of observed variables L is obtained by calculating the above formula obs ;

[0147] T ITSC The working point load is the sum of the loads of M–t obs lines. For the t obs in L obs –1 line loads are gradually decreased by unit load, and the minimum value of Σ m∈Λ L m is calculated to obtain the first data from L obs to the lower boundary point;

[0148] The working point load is the sum of the loads of M–t obs lines. For the t obs in L obs –1 line loads are gradually increased by unit load, and the maximum value of Σ m∈Λ L m is calculated to obtain the second data from L obs to the upper boundary point;

[0149] Finally, based on the first data and the second data, the safety boundary data of the simplified safety model in the t obs -dimensional space are obtained by using the data fitting method, so as to evaluate whether the integrated energy system is in a safe operating state according to the safety boundary data, and the observation of the characteristic structure of the safety domain can be realized in the t obs -dimensional space.

[0150] The feasibility of the above method is verified by an example below.

[0151] The integrated energy system contains a total of 2 energy hubs, and the total transformer capacity is 28 MVA. PV1 is connected to the system in a centralized manner, and PV2, PV3 and WT are connected to the system in a distributed manner, with rated powers of 1.0, 1.0, 1.0, 2.5 MW respectively. The system power factor is set to 0.85. The branch flow of the thermal network is less than 23.91 kg / s, the upper and lower limits of the supply water temperature are 100°C and 98.5°C respectively, and the upper and lower limits of the return water temperature are 50°C and 48.5°C respectively. The upper and lower limits of the gas network node pressure are 60 mbar and 90 mbar respectively, and the branch flow is less than 0.334 MMCF / D. The key equipment and line parameters in EH1 are shown in Table 1.

[0152] Table 1

[0153]

[0154]

[0155] The key equipment and line parameters in EH2 are shown in Table 2.

[0156] Table 2

[0157]

[0158] The comparison between the non-simplified safety model and the simplified safety model in terms of energy supply capacity is shown in Table 3. Since the energy supply capacities obtained by the two solution methods are approximately the same, the simplified safety model proposed in the present invention can meet the calculation accuracy requirements.

[0159]

[0160] According to the formula in the above steps, a set of line loads L at the upper and lower limit operating points of the energy supply capacity can be calculated m , as shown in Table 4. Randomly select L1, L2, and L9 in Table 4 as observation variables, and solve the upper and lower boundaries of the three-dimensional safety region according to the results of the present invention, as Figure 4 shown. The simplified safety model is as shown in the Figure 4 gray area, and the non-simplified safety model is as shown in the Figure 4 black dots. By comparison, it can be seen that the upper and lower boundaries of the simplified safety model coincide with those of the non-simplified safety model, and the boundary errors are only 0.09% and 0.21%, which also shows that the simplified model can meet the accuracy requirements.

[0161]

[0162]

[0163] Randomly select L1, L2, and L9 in Table 4 as observation variables to construct a three-dimensional space ABC-FED, as Figure 5 shown. The coordinates of each point are A(3, 0, 0), B(0, 0, 0), C(0, 3, 0), D(0, 3, 5.83), E(0, 0, 5.83), F(3, 0, 5.83). N and M are the operating points of T ITSC and respectively, and the relevant data are shown in Table 4. The operating points of T ITSC , are located on HJ and FD. Therefore, the safety regions obtained according to the operating points N and M are represented by ABC-HKJ and GLI-FED respectively. The coordinates of each point are H(3, 0, 3.75), K(0, 0, 3.75), J(0, 3, 3.75), G(3, 0, 2.94), L(0, 0, 2.94), I(0, 3, 2.94). They are represented by the plane HKJ and the plane FED respectively. They are represented by plane ABC and plane GLI respectively. Among them, the shaded area GLI-HKJ is the area that cannot be affected by the uncertainty of renewable energy, and the operating point located within this area is 100% safe; the safety of the operating points in the ABC-FED area outside this area will be affected by the uncertainty of renewable energy.

[0164] For Figure 5 In the safe area, the boundaries of the safe area and the internal / external operating points A(3, 0, 0), A”(0.8, 1.5, 3), and A'(2, 2, 0) are selected. The reference safety of the energy hub equipment and lines is shown in Table 5, and the safety boundary distances of each operating point are shown in Table 6.

[0165] Table 5

[0166]

[0167]

[0168] Table 6

[0169]

[0170] As can be seen from Table 6, the safety boundary distances of point A are all non-negative values, so it is a safe operating point. The reference safety of the equipment and lines at operating point A is shown in Table 5. Most of the equipment and lines at operating point A have passed the reference safety verification, and only four pieces of equipment and lines have a critical reference safety state. Because operating point A is located at the boundary of the safe area, the equipment and lines in the critical state are vulnerable to load fluctuations. When the load increases, operating point A will evolve into operating point A' outside the safe area. As can be seen from Table 6, the safety boundary distance of point A' has negative values, so it is an unsafe operating point. The reference safety of the equipment and lines at operating point A' is shown in Table 5, and there are four pieces of equipment and lines that have not passed the reference safety verification. Therefore, the operating point A' outside the safe area is in an unsafe state, which is consistent with the theoretical analysis results of the present invention. When the load decreases, operating point A will evolve into operating point A” inside the safe area. As can be seen from Table 7, the safety boundary distances of point A” are all positive values, so it is a safe operating point. The reference safety of the equipment and lines at operating point A” is shown in Table 5, and its equipment and lines have all passed the reference safety verification, indicating that the operating point A” within the area that cannot be affected by the uncertainty of renewable energy is in a 100% safe state, which is consistent with the theoretical analysis results of the present invention. It shows that to ensure the safe and stable operation of the integrated energy system, priority should be given to controlling the operating point within the area that cannot be affected by the uncertainty of renewable energy.

[0171] Please refer to Figure 6 , an embodiment of the present invention provides an integrated energy system operation evaluation device based on a safety boundary. The device includes:

[0172] The first modeling module 600 is configured to establish a system security model with the line reference safety and equipment reference safety of the energy system as constraints according to the probabilistic power of renewable energy; wherein, the system security model includes all operating points that operate safely under the reference safety inspection constraints.

[0173] The second modeling module 602 is configured to sequentially establish a safety boundary model and a safety distance model of the integrated energy system according to the simplified system security model, and establish a reduced-dimensional observation model of the integrated energy system according to the maximum energy supply capacity of the system.

[0174] The calculation module 604 is configured to solve the reduced-dimensional observation model to obtain boundary data for evaluating whether the integrated energy system is in a safe operating state.

[0175] In an embodiment of the present invention, when the first modeling module 600 executes the operation of establishing a system security model with the line reference safety and equipment reference safety of the energy system as constraints according to the probabilistic power of renewable energy, it is specifically configured to perform the following operations:

[0176] According to the probabilistic power, respectively determine the line energy supply change function and the equipment energy supply change function of the integrated energy system;

[0177] Solve the line energy supply change function according to the access mode of the renewable energy and the integrated energy system, respectively calculate the upper and lower limits of the line reference safety constraint and the upper and lower limits of the equipment reference safety constraint, and establish the system security model according to the calculation results.

[0178] In an embodiment of the present invention, the upper and lower limits of the line reference safety constraint are respectively calculated by the following formulas, where:

[0179] When the renewable energy is distributedly accessed to the integrated energy system, the first constraint upper limit of the line reference safety constraint is:

[0180]

[0181] In the formula, L lmn,shift is the load transferred by line n after line m fails and stops operating; L n is the original load of line n; C ln is the rated value of the capacity of line n; C EES is the rated charge-discharge power of the electrical energy storage, with discharge greater than 0 and charge less than 0; n RE is the number of renewable energy devices; C pro is the probabilistic power;

[0182] When the renewable energy is connected to the integrated energy system in a centralized manner, the second constraint upper limit of the line reference safety constraint is:

[0183]

[0184] The constraint lower limit of the line reference safety constraint is:

[0185]

[0186] In the formula, P con is the power consumption of the electrical equipment.

[0187] In the embodiments of the present invention, the upper limit and the lower limit of the equipment reference safety constraint are respectively calculated by the following formulas, where:

[0188] When the renewable energy is connected to the integrated energy system in a distributed manner, the first constraint upper limit of the equipment reference safety constraint is:

[0189]

[0190] In the formula, H T and H CHP are the loads supplied by the transformer and the combined heat and power unit respectively; C CHP is the rated power of the combined heat and power unit; c u is the upper limit of the heat-electricity ratio coefficient of the combined heat and power unit; C HES1 is the rated heat storage / discharge power of the heat energy storage HES1, the heat discharge is greater than 0, and the heat storage is less than 0;

[0191] When the renewable energy is connected to the integrated energy system in a centralized manner, the second constraint upper limit of the equipment reference safety constraint is:

[0192]

[0193] The constraint lower limit of the line reference safety constraint is:

[0194] H T +H CHP ≥max(H T +P con ,c m (L n -C HES1 )+C EES +n RE C pro )=C RE,equ

[0195] In the formula, CRE,equ is the lower limit of equipment constraint.

[0196] In an embodiment of the present invention, when the second modeling module 602 executes the operation of sequentially establishing a security boundary model and a security distance model of the integrated energy system according to the simplified system security model, and establishing a reduced-dimensional observation model of the integrated energy system according to the energy supply capacity of the system, it is specifically used to perform the following operations:

[0197] Perform a simplification process on the system security model to obtain a simplified security model:

[0198]

[0199] where Ω IES-SR is the security region of the integrated energy system; L is the working point vector, L = (L1,... L m ,, L M ) M×1 , M is the number of lines; h(L)=0 is the multi-energy flow balance constraint; and are respectively the column matrices of the upper and lower limits of the energy supply capacity of the d-th row; and are respectively the interval values from the upper and lower limits of the energy supply capacity; λ l , λ u are respectively the line parameters corresponding to the upper and lower limits of the reference security constraint; Ω IES-USR is the set of working points that satisfy the reference security constraint under any probability power of renewable energy

[0200] According to the simplified security model, establish a security boundary model corresponding to line m

[0201]

[0202] where are respectively the upper and lower security boundaries of Ω IES-SR corresponding to line m; are respectively and 's upper limits; are respectively and 's lower limits;

[0203] According to the security boundary model, establish a security distance model for characterizing the vertical distance from the working point m' to

[0204]

[0205] where are respectively the vertical distances from the working point m' to distance; are respectively the upper and lower limits of; are respectively the upper and lower limits of;

[0206] According to the energy supply capacity T of the system ITSC :

[0207]

[0208] wherein, T ITSC is the energy supply capacity; T ITSC are respectively the upper and lower bounds of the ITSC operating point;

[0209] Establish a reduced - dimension observation model of the integrated energy system:

[0210]

[0211] Λ = {e|e ∈ {b1×1,…,b i ×i,…,b M ×M}, e≠0}

[0212] L obs = {L m |m ∈ Λ}

[0213] wherein, F DRO is the reduced - dimension observation function; is for T ITSC corresponding to the minimum value; L obs is the optimized set of observation variables; Λ is the line set of the optimized observation variables; b i is a 0 - 1 variable, b i = 1 indicates that line i is an observation variable.

[0214] In the embodiment of the present invention, when the calculation module 604 executes the solution of the reduced - dimension observation model to obtain the boundary data for evaluating whether the integrated energy system is in a safe operating state, it is specifically used to perform the following operations:

[0215] Select the loads of t obs lines as observation variables according to the ITSC operating point; wherein, 0 < t obs ≤M;

[0216] Perform calculations on the initialized ITSC operating point to obtain and T ITSC , and the line outlet loads corresponding to each ITSC operating point;

[0217] Solve the circuit set Λ after initialization processing, and calculate to obtain the optimized set of observed variables L obs ;

[0218] For L obs Among them, the loads of t obs –1 circuits gradually decrease with unit load, and for Σ m∈Λ L m calculate the minimum value to obtain the first data from L obs to the lower boundary point;

[0219] For L obs Among them, the loads of t obs –1 circuits gradually increase with unit load, and for Σ m∈Λ L m calculate the maximum value to obtain the second data from L obs to the upper boundary point;

[0220] According to the first data and the second data, use the data fitting method to obtain the safety boundary data of the simplified safety model in the t obs -dimensional space, so as to evaluate whether the integrated energy system is in a safe operating state according to the safety boundary data.

[0221] It should be noted that: the above-mentioned integrated energy system operation evaluation device based on the safety boundary provided by the above embodiments is only illustrated by the division of the above functional modules. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the integrated energy system operation evaluation device based on the safety boundary provided by the above embodiments and the embodiments of the integrated energy system operation evaluation method based on the safety boundary belong to the same concept, and the specific implementation process is detailed in the method embodiments, which will not be repeated here.

[0222] An embodiment of the present application also provides a computer device. Please refer to Figure 7 , this computer device includes a processor and a memory. At least one instruction, at least one program, a code set or an instruction set is stored in the memory. At least one instruction, at least one program, a code set or an instruction set is loaded and executed by the processor to implement the integrated energy system operation evaluation method based on the safety boundary provided by the above method embodiments.

[0223] An embodiment of the present application also provides a computer-readable storage medium. At least one instruction, at least one program, a code set or an instruction set is stored on this computer-readable storage medium. At least one instruction, at least one program, a code set or an instruction set is loaded and executed by the processor to implement the integrated energy system operation evaluation method based on the safety boundary provided by the above method embodiments.

[0224] An embodiment of the present application further provides a computer program product, which includes a computer program. The processor of the computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes the method for evaluating the operation of an integrated energy system based on a security boundary described in any one of the above embodiments.

[0225] For the convenience of description, when describing the above system or device, it is divided into various modules or units according to functions for separate description. Of course, when implementing the present application, the functions of each unit can be implemented in one or more software and / or hardware.

[0226] From the description of the above embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present application.

[0227] Finally, it should also be noted that in this article, relational terms such as first, second, third, and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0228] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A method for evaluating the operation of an integrated energy system based on a safety boundary, characterized in that, The method includes: Based on the probabilistic power of renewable energy, a system security model is established with the line reference security and equipment reference security of the energy system as constraints; wherein, the system security model includes all operating points that operate safely under the reference security inspection constraints. Based on the simplified system security model, a security boundary model and a security distance model of the integrated energy system are established in sequence, and a reduced-dimensional observation model of the integrated energy system is established according to the maximum energy supply capacity of the system. Solve the reduced-dimensional observation model to obtain boundary data for evaluating whether the integrated energy system is in a safe operating state.

2. The method according to claim 1, wherein The establishment of a system security model with the line reference security and equipment reference security of the energy system as constraints based on the probabilistic power of renewable energy includes: Based on the probabilistic power, the line energy supply change function and the equipment energy supply change function of the integrated energy system are determined respectively. Solve the line energy supply change function according to the access mode of the renewable energy and the integrated energy system, calculate the upper and lower limits of the line reference security constraint and the upper and lower limits of the equipment reference security constraint respectively, and establish the system security model according to the calculation results.

3. The method according to claim 2, characterized in that The upper and lower limits of the line reference security constraint are calculated by the following formulas respectively, where: When the renewable energy is distributedly connected to the integrated energy system, the first constraint upper limit of the line reference security constraint is as follows: Where, L lmn,shift is the load transferred from line n after line m fails and is out of service; L n is the original load of line n; C ln is the rated value of the capacity of line n; C EES is the rated charge-discharge power of the electrical energy storage, with discharge greater than 0 and charge less than 0; n RE is the number of renewable energy devices; C pro is the probabilistic power; When the renewable energy is connected to the integrated energy system in a centralized manner, the second constraint upper limit of the line reference security constraint is as follows: The lower limit of the line reference security constraint is as follows: Where P con is the power consumption of the electrical equipment.

4. The method according to claim 3, wherein The upper and lower limits of the equipment reference security constraint are calculated by the following formulas respectively, where: When the renewable energy is distributedly accessed to the integrated energy system, the first constraint upper limit of the device reference safety constraint is as follows: Where, H T and H CHP are the loads supplied by the transformer and the combined heat and power unit respectively; C CHP is the rated power of the combined heat and power unit; c u is the upper limit of the electric-to-heat ratio coefficient of the combined heat and power unit; C HES1 is the rated heat storage / discharge power of the heat energy storage HES1, with heat discharge greater than 0 and heat storage less than 0; When the renewable energy is connected to the integrated energy system in a centralized manner, the second constraint upper limit of the device benchmark safety constraint is as follows: The lower limit of the line reference security constraint is: H T +H CHP ≥max(H T +P con ,c m (L n -C HES1 )+C EES +n RE C pro )=C RE,equ where C RE,equ is the lower limit of the device constraint.

5. The method according to claim 2, wherein The establishment of a security boundary model and a security distance model of the integrated energy system in sequence based on the simplified system security model, and the establishment of a reduced-dimensional observation model of the integrated energy system according to the energy supply capacity of the system includes: Simplify the system security model to obtain a simplified security model: where, Ω IES-SR is the safety region of the integrated energy system; L is the working point vector, L = (L1, … L m , …, L M ), M×1 , M is the number of lines; h(L) = 0 is the multi-energy flow balance constraint; and are respectively the column matrices of the upper and lower limits of the energy supply capacity of the d-th row; and are respectively the interval values from the upper and lower limits of the energy supply capacity; λ l , λ u are respectively the line parameters corresponding to the upper and lower limits of the reference safety constraint; Ω IES-USR is the set of working points that satisfy the reference safety constraint under any probability power of renewable energy According to the simplified security model, establish a security boundary model corresponding to line m In the formula, are respectively the Ω corresponding to line m IES-SR safe upper and lower boundaries; are respectively and upper limits; are respectively and lower limits; According to the safety boundary model, a safety distance model is established to represent the vertical distance from the operating point m′ to ​ In the formula, are respectively the distances from the working point m′ to ; are respectively the upper and lower limits of ; are respectively the upper and lower limits of ; According to the energy supply capacity T of the system ITSC : where T ITSC is the energy supply capacity; T ITSC are the upper and lower bounds of the ITSC operating point, respectively; Establish a reduced-dimensional observation model of the integrated energy system: L obs = {L m | m ∈ Λ} Where F DRO is the dimensionality reduction observation function; is T ITSC the corresponding minimum value; L obs is the optimized set of observation variables; Λ is the line set of the optimized observation variables; b i is a 0-1 variable, b i = 1 indicates that line i is an observation variable.

6. The method according to claim 5, characterized in that, Solving the reduced-dimensional observation model to obtain boundary data for evaluating whether the integrated energy system is in a safe operating state includes: Select the load of t obs lines as the observed variable, where 0 < t obs ≤ M; Calculate the ITSC operating points after initialization processing to obtain and T ITSC , and the line outlet load corresponding to each ITSC operating point; Solve the circuit set Λ after initialization processing, and calculate to obtain the optimized set of observed variables L obs ; For L obs In t obs – The loads of 1 line decrease gradually with unit load respectively, and calculate the minimum value of ∑ m∈Λ L m to obtain the first data from L obs to the lower boundary point; For L obs In t obs – The loads of 1 line increase gradually with unit load respectively, and calculate the maximum value of ∑ m∈Λ L m to obtain the second data from L obs to the upper boundary point; Based on the first data and the second data, boundary data of a simplified security model in a t obs -dimensional space is obtained by using a data fitting method, so as to evaluate whether the integrated energy system is in a safe operating state according to the boundary data.

7. An integrated energy system operation evaluation device based on a safety boundary, characterized in that, The device includes: A first modeling module for establishing a system security model with the line reference security and equipment reference security of the energy system as constraints based on the probabilistic power of renewable energy; wherein, the system security model includes all operating points that operate safely under the reference security inspection constraints. A second modeling module for establishing a security boundary model and a security distance model of the integrated energy system in sequence based on the simplified system security model, and establishing a reduced-dimensional observation model of the integrated energy system according to the maximum energy supply capacity of the system. A calculation module for solving the reduced-dimensional observation model to obtain boundary data for evaluating whether the integrated energy system is in a safe operating state.

8. A computer device, characterized in that, The computer device includes a memory and a processor. The memory is used to store a computer program, and the processor is used to execute the computer program stored on the memory to implement the steps of the method according to any one of claims 1-6 above.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and when the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-6.

10. A computer program product, characterized in that, including a computer program which, when executed by a processor, implements the steps of the method according to any one of claims 1-6.

Images