An incremental distribution network power balance margin assessment method for dispatch planning

Abstract

The present invention discloses a method for evaluating the electric quantity balance margin of an incremental distribution network for a scheduling plan. The method adopts an electric quantity balance margin evaluation method for an incremental distribution network based on a state matrix. First, the state is divided according to the current electric quantity balance margin of the incremental distribution network, and the ability of the energy storage device to absorb the randomness of unbalanced power is evaluated. Then, the output of the controllable power source is taken into account, and finally, the evaluation index value of the electric quantity balance margin of the incremental distribution network is calculated. The effective evaluation of the dispatchable capacity of the incremental distribution network including positive standby power, negative standby power, unbalanced power generation surplus power, and unbalanced power generation missing power is achieved. The problem of the lack of electric quantity balance margin evaluation index in the operation control of the incremental distribution network is solved, so as to improve the evaluation accuracy in the scheduling operation process and increase the flexibility of scheduling control.

Description

Technical Field

[0001] The invention relates to a method for evaluating the balance margin of an incremental distribution network electricity quantity oriented to a dispatching plan, and belongs to the technical field of distribution network operation. Background Art

[0002] With the continuous deepening of my country's power system reform, the incremental distribution network will be connected to the distribution network on a large scale, which will bring great challenges to the dispatching and operation management of the power grid. The incremental distribution network refers to the local power grids of 110kV and below voltage level and 220 (330) kV and below voltage level industrial parks (economic development zones) and other newly invested, constructed and operated local power grids in addition to the existing assets of power grid enterprises. With the large-scale application of the incremental distribution network, the output of the distributed power sources inside it has a large randomness, which leads to an increase in the complexity of various factors related to power grid security, such as unit output and startup combination, flow mode, and spare capacity, which in turn increases the complexity of the operation mode arrangement and squeezes the flexibility of the operation mode arrangement. Objectively, it causes the dispatching agency to have a reduced ability to control the operation of the power grid and increases the difficulty of dispatching to ensure the safety of the power grid.

[0003] The traditional dispatch plan is made by the dispatching agency in accordance with the mandatory plan, annual and monthly power purchase plan and other medium- and long-term plans, combined with the system operation status of the next day, load forecast level, network constraints, channel blockage, transmission and transformation equipment maintenance, unit startup combination, etc., in accordance with the principles of unified dispatch and hierarchical management.

[0004] After the large-scale application of incremental distribution networks, the power market has become richer, and the components of the power transmission and transformation plan have become more complex and diversified. For example, for power plant power generation plans, it is necessary to consider the annual long-term contract power, monthly competitive power, day-ahead intraday trading power, incremental trading, etc. required by the incremental distribution network, which makes the power generation scheduling model more complex and increases the complexity of scheduling execution.

[0005] The large-scale grid connection of incremental distribution networks has put forward higher requirements for the standardization and leanness of dispatching operations. In the new round of power system reform and power marketization environment, dispatching behavior is affected by power market transactions, the degree of information disclosure has increased, and social supervision has increased. Therefore, dispatching agencies must improve the leanness of dispatching decisions and continuously improve the management level of operation modes while strictly dispatching in accordance with laws and regulations and implementing relevant technical standards, so as to ensure the safe and stable operation of the power grid, reliable and orderly power supply to users, and efficient and orderly operation of the power market, so as to achieve the coordination and unification of power grid safety and market efficiency.

[0006] The connection of incremental distribution network to the grid will bring a series of operation and control problems. The operation characteristics of incremental distribution network are not clear enough, and a multi-level incremental distribution network management method has not been formed. The operation and control modes are very different. The operation modes, power generation and consumption plans, and new energy consumption are very different. It is easy to have problems such as poor power supply quality and low power supply reliability, and there are risks of safe and stable operation. In order to solve the operation and control problems brought about by the connection of incremental distribution network to the grid and meet the new needs of energy Internet, it is necessary to meet the overall coordination of energy network load storage coordination, multi-energy coordination and various control forms. It is necessary to make full use of the coupling interaction between traditional distribution network and incremental distribution network to realize the advancement of distribution network dispatching and operation decision-making methods. In order to realize the standardized management and orderly control of incremental distribution network by power grid dispatching, it is necessary to effectively dispatch and control the incremental distribution network, correctly evaluate the power balance margin of the incremental distribution network, master the operation characteristics of the incremental distribution network, and form a multi-level distribution network dispatching and control mode with incremental distribution network as the object to support accurate and efficient operation and control of power grid dispatching. Summary of the invention

[0007] The purpose of the present invention is to provide a method for evaluating the balance margin of an incremental distribution network for dispatching plans, in order to solve the problem of the lack of evaluation indicators for the balance margin of an incremental distribution network in operation control. The present invention proposes a method for evaluating the balance margin of an incremental distribution network that is subject to dispatching control, taking into account relevant factors such as load, power supply, and energy storage in the incremental distribution network, to achieve an effective evaluation of the dispatchable capacity of the incremental distribution network including positive reserve power, negative reserve power, unbalanced power generation surplus power, and unbalanced power generation missing power, so as to improve the evaluation accuracy during the dispatching operation process and increase the flexibility of dispatching control.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for evaluating the balance margin of an incremental distribution network for a scheduling plan includes the following steps:

[0010] (1) Define the evaluation index of the incremental distribution network power balance margin

[0011] Within a planning period T, the incremental distribution network, without external power support and on the premise of meeting its own load demand, has a power balance margin as a whole, which is described by the following four indicators: Positive reserve power E out , Negative reserve power E in 、Unbalanced power generation surplus E g 、Unbalanced power generation missing amount E L , the specific definitions of each indicator are as follows:

[0012] Positive reserve power E out: The maximum amount of electricity that the incremental distribution network can provide to the outside world within a planning period T while meeting its own load demand. The relevant variables include the minimum value of the unbalanced power generation surplus in the incremental distribution network, the minimum energy storage capacity, and the remaining power generation of the controllable power source;

[0013] Negative reserve power E in : In a planning period T, the incremental distribution network can absorb the maximum amount of externally injected electricity. The relevant variables include the remaining storage space and the minimum unbalanced generation missing electricity.

[0014] Unbalanced power generation surplus E g : The maximum surplus power generation that cannot be absorbed by the internal load and storage energy of the incremental distribution network within a planning period T;

[0015] Unbalanced power generation missing amount E L : The maximum missing power generation caused by insufficient power generation in the incremental distribution network within a planning period T;

[0016] (2) Evaluation method of power balance margin of incremental distribution network

[0017] 1) Power balance margin state vector

[0018] Assume that the state vector of the power balance margin is x, then the state x of the power balance margin at time t is t It is expressed as:

[0019] x t =[A s,t ,A e,t ,E RaR,t ,E LaR,t ] x t ∈Ω (1)

[0020] Where, Ω is the incremental distribution network power balance margin state matrix, A s,t A is the amount of energy stored in the incremental distribution network at time t, e,t is the chargeable amount of energy storage in the incremental distribution network at time t, E RaR,t is the risk reserve power at time t, that is, the surplus power of the incremental distribution network under the confidence level β within the period T; E LaR,t is the risk power shortage at time t, that is, the power shortage of the incremental distribution network under the confidence level β within the period T; E RaR,t and E LaR,t The calculation formula is as follows:

[0021]

[0022] Where N is the number of sampling points in period T, τ is the sampling interval, and N0 is the risk reserve R aR The sampling point corresponding to 0, N01 The next sampling point is the one corresponding to the sampling point where the risk reserve is equal to 0;

[0023] The constraints of the power balance margin at time t are as follows:

[0024] A s,t +A e,t ≤A (3)

[0025] Where A is the difference between the maximum and minimum storage capacity of the energy storage device;

[0026] First, the balance margin of electricity is calculated when only the energy storage device is considered, and the unbalanced risk electricity ΔE is used to measure it. RaR Subtract the risk of power shortage E LaR , the calculation formula is as follows:

[0027] ΔE=E RaR -E LaR (4)

[0028] 2) State matrix partitioning

[0029] According to the unbalanced risk power ΔE and the stored power A in the incremental distribution network at time t s,t , the chargeable amount of energy stored in the incremental distribution network at time t A e,t The value of , divides the state matrix of the power balance margin into 12 sub-states as follows:

[0030] (1) ΔE ≥ 0, A e,t ≥E RaR,t ,A s,t ≥E LaR,t

[0031] (2) ΔE ≥ 0, A e,t ≥E RaR,t ,A s,t <E LaR,t

[0032] (3) ΔE ≥ 0, ΔE ≤ A e,t <E RaR,t , A s,t ≥E LaR,t

[0033] (4) ΔE ≥ 0, ΔE ≤ A e,t <E RaR,t , A s,t <E LaR,t

[0034] ⑸ΔE≥0,A e,t <ΔE,A s,t ≥E LaR,t

[0035] ⑹ΔE≥0,Ae,t <ΔE,A s,t <E LaR,t

[0036] ⑺ΔE<0,A s,t ≥E LaR,t ,A e,t ≥E RaR,t

[0037] ⑻ΔE<0,A s,t ≥E LaR,t ,A e,t <E RaR,t

[0038] ⑼ΔE<0,▕ΔE▏≤A s,t <E LaR,t , A e,t ≥E RaR,t

[0039] ⑽ΔE<0,▕ΔE▏≤A s,t <E LaR,t , A e,t <E RaR,t

[0040] ⑾ΔE<0,A s,t <▕ΔE▏,A e,t ≥E RaR,t

[0041] ⑿ΔE<0,A s,t <▕ΔE▏,A e,t <E RaR,t

[0042] 3) Calculation of power balance margin only taking into account energy storage devices

[0043] Calculate the power balance margin state vector x when only the energy storage device is considered t Unbalanced generation surplus in different subspaces Unbalanced power generation and missing electricity The amount of electricity stored at the end of the cycle is A s,t+T 、The amount of electricity that can be stored at the end of the cycle is A e,t+T , these four values ​​characterize the ability of the energy storage device to smooth out unbalanced power;

[0044] According to the state matrix partitioning method, the power balance margin evaluation index at time t can be calculated as follows:

[0045] (1) A s,t+T =A s,t +ΔE,A e,t+T =[A e,t -ΔE]

[0046] (2) A s,t+T =[A s,t +ΔE,E RaR,t ],A e,t+T =[A s,t -E RaR,t ,A e,t -ΔE]

[0047] (3) A s,t+T =[A-E LaR,t ,A s,t +ΔE],A e,t+T =[A e,t -ΔE,E LaR ]

[0048] (4) A s,t+T =[A-E LaR,t ,E RaR,t ],A e,t+T =[A-E RaR,t ,E LaR,t ]

[0049] (5) A s,t+T =[A-E LaR,t ,A],A e,t+T =[0,E LaR,t ]

[0050] (6) A s,t+T =[A-E LaR,t ,A],A e,t+T =[0,E LaR,t ]

[0051] (7) A s,t+T =A s,t -|ΔE|,A e,t+T =A e,t +|ΔE,|

[0052] (8) A s,t+T =[A-E LaR,t ,A s,t -|ΔE],A e,t+T =[A e,t +|ΔE|,E LaR,t ]

[0053] (9) A s,t+T =[A s,t -ΔE|,E RaR,t ],A e,t+T =[A-ERaR,t ,A e,t +|ΔE|]

[0054] (10) A s,t+T =[AE LaR,t ,E RaR,t ], A e,t+T =[AE RaR,t ,E LaR,t ]

[0055] (11) A s,t+T =[0,E RaR,t ], A e,t+T =[AE RaR,t ,A]

[0056] (12) A s,t+T =[0,E RaR,t ], A e,t+T =[AE RaR,t ,A]

[0057] 4) Calculation of power balance margin taking into account controllable power supply

[0058] The controllable power source is the photovoltaic and wind power generation system in the incremental distribution network. The unbalanced power generation missing amount ΔE of the incremental distribution network in the period T is L

[0059]

[0060] In the formula, G is the maximum value of the unbalanced power generation missing in the incremental distribution network after energy storage regulation; 0 is the maximum controllable power generation of the incremental distribution network in period T, P Gn,j is the rated power of the jth controllable power supply; G is the power generation of the controllable power supply after the controllable power supply reduces the unbalanced power generation loss;

[0061] 5) Calculation of evaluation index of incremental distribution network power balance margin

[0062] ①Positive reserve power E out

[0063]

[0064] In the formula, is the minimum unbalanced power generation surplus of the incremental distribution network in period T, A s,t+T,min is the minimum power storage at the end of period T;

[0065] ②Negative reserve power E in

[0066]

[0067] In the formula, is the minimum unbalanced power generation missing quantity of the incremental distribution network in period T, A e,t+T,min is the minimum amount of electricity that can be stored in the incremental distribution network at the end of period T;

[0068] ③ Unbalanced power generation surplus E g

[0069]

[0070] In the formula, is the maximum unbalanced power generation surplus that may occur in the incremental distribution network in the next cycle T;

[0071] ④ Unbalanced power generation missing electricity E L

[0072] E L =ΔE L (11)

[0073] Among the above four evaluation indicators, positive reserve power and negative reserve power are used to describe the source-load characteristics of the incremental distribution network in the next cycle T, and unbalanced generation surplus power and unbalanced generation missing power are used to describe the operating status of the incremental distribution network in the next stage.

[0074] Compared with the prior art, the beneficial effects of the present invention are: using a state matrix-based incremental distribution network power balance margin assessment method, firstly, the state is divided according to the current power balance margin of the incremental distribution network, the ability of the energy storage device to absorb the randomness of unbalanced power is assessed, and then the controllable power output is taken into account, and finally the assessment index value of the power balance margin of the incremental distribution network is calculated. Effective assessment of the dispatchable capacity of the incremental distribution network including positive standby power, negative standby power, unbalanced power generation surplus power, and unbalanced power generation missing power is achieved. The problem of the lack of power balance margin assessment indicators in the operation control of the incremental distribution network is solved, so as to improve the assessment accuracy in the dispatching operation process and increase the dispatching control flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is a flow chart of the power balance margin evaluation of the present invention. DETAILED DESCRIPTION

[0076] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0077] The calculation process of the incremental distribution network power balance margin evaluation index is as follows: Figure 1 As shown, first calculate the current state of the incremental distribution network x t, determine the state subspace to which the incremental distribution network belongs in the next cycle, including the remaining power of unbalanced generation Unbalanced power generation and missing electricity And the amount of electricity stored at the end of the cycle A s,t+T , the amount of electricity that can be stored at the end of the cycle is A e,t+T ; Finally, the four evaluation indicators of power balance margin are calculated.

[0078] The detailed steps are as follows:

[0079] (1) Define the evaluation index of the incremental distribution network power balance margin

[0080] Within a planning period T, the incremental distribution network, without external power support and on the premise of meeting its own load demand, has a power balance margin as a whole, which is described by the following four indicators: Positive reserve power E out , Negative reserve power E in 、Unbalanced power generation surplus E g 、Unbalanced power generation missing amount E L , the specific definitions of each indicator are as follows:

[0081] Positive reserve power E out : The maximum amount of electricity that the incremental distribution network can provide to the outside world within a planning period T while meeting its own load demand. The relevant variables include the minimum value of the unbalanced power generation surplus in the incremental distribution network, the minimum energy storage capacity, and the remaining power generation of the controllable power source;

[0082] Negative reserve power E in : In a planning period T, the incremental distribution network can absorb the maximum amount of externally injected electricity. The relevant variables include the remaining storage space and the minimum unbalanced generation missing electricity.

[0083] Unbalanced power generation surplus E g : The maximum surplus power generation that cannot be absorbed by the internal load and storage energy of the incremental distribution network within a planning period T;

[0084] Unbalanced power generation missing amount E L : The maximum missing power generation caused by insufficient power generation in the incremental distribution network within a planning period T;

[0085] (2) Evaluation method of power balance margin of incremental distribution network

[0086] 1) Power balance margin state vector

[0087] Assume that the state vector of the power balance margin is x, then the state x of the power balance margin at time t is t It is expressed as:

[0088] x t=[A s,t ,A e,t ,E RaR,t ,E LaR,t ] x t ∈Ω (1)

[0089] Where, Ω is the incremental distribution network power balance margin state matrix, A s,t A is the amount of energy stored in the incremental distribution network at time t, e,t is the chargeable amount of energy storage in the incremental distribution network at time t, E RaR,t is the risk reserve power at time t, that is, the surplus power of the incremental distribution network under the confidence level β within the period T; E LaR,t is the risk power shortage at time t, that is, the power shortage of the incremental distribution network under the confidence level β within the period T; E RaR,t and E LaR,t The calculation formula is as follows:

[0090]

[0091] Where N is the number of sampling points in period T, τ is the sampling interval, and N0 is the risk reserve R aR The sampling point corresponding to 0, N 01 The next sampling point is the one corresponding to the sampling point where the risk reserve is equal to 0;

[0092] The constraints of the power balance margin at time t are as follows:

[0093] A s,t +A e,t ≤A (3)

[0094] Where A is the difference between the maximum and minimum storage capacity of the energy storage device;

[0095] First, the balance margin of electricity is calculated when only the energy storage device is considered, and the unbalanced risk electricity ΔE is used to measure it. RaR Subtract the risk of power shortage E LaR , the calculation formula is as follows:

[0096] ΔE=E RaR -E LaR (4)

[0097] 2) State matrix partitioning

[0098] According to the unbalanced risk power ΔE and the stored power A in the incremental distribution network at time t s,t , the chargeable amount of energy stored in the incremental distribution network at time t A e,t The value of , divides the state matrix of the power balance margin into 12 sub-states as shown in the following table:

[0099]

[0100] 3) Calculation of power balance margin only taking into account energy storage devices

[0101] Calculate the power balance margin state vector x when only the energy storage device is considered t Unbalanced generation surplus in different subspaces Unbalanced power generation and missing electricity The amount of electricity stored at the end of the cycle is A s,t+T 、The amount of electricity that can be stored at the end of the cycle is A e,t+T , these four values ​​characterize the ability of the energy storage device to smooth out unbalanced power;

[0102] According to the state matrix partitioning method, the power balance margin evaluation index at time t can be calculated as follows:

[0103] (1) A s,t+T =A s,t +ΔE,A e,t+T =[A e,t -ΔE]

[0104] (2) A s,t+T =[A s,t +ΔE,E RaR,t ], A e,t+T =[A s,t -E RaR,t ,A e,t -ΔE]

[0105] (3) A s,t+T =[AE LaR,t ,A s,t +ΔE],A e,t+T =[A e,t -ΔE,E LaR ]

[0106] (4) A s,t+T =[AE LaR,t ,E RaR,t ], A e,t+T =[AE RaR,t ,E LaR,t ]

[0107] (5) A s,t+T =[AE LaR,t ,A],A e,t+T =[0,E LaR,t ]

[0108] (6) As,t+T =[AE LaR,t ,A],A e,t+T =[0,E LaR,t ]

[0109] (7) A s,t+T =A s,t -|ΔE|,A e,t+T =A e,t +|ΔE|

[0110] (8) A s,t+T =[AE LaR,t ,A s,t -|ΔE|],A e,t+T =[A e,t +|ΔE|,E LaR,t ]

[0111] (9) A s,t+T =[A s,t -|ΔE|,E RaR,t ], A e,t+T =[AE RaR,t ,A e,t +|ΔE|]

[0112] (10) A s,t+T =[AE LaR,t ,E RaR,t ], A e,t+T =[AE RaR,t ,E LaR,t ]

[0113] (11) A s,t+T =[0,E RaR,t ], A e,t+T =[AE RaR,t ,A]

[0114] (12) A s,t+T =[0,E RaR,t ], A e,t+T =[AE RaR,t ,A]

[0115] 4) Calculation of power balance margin taking into account controllable power supply

[0116] The controllable power source is the photovoltaic and wind power generation system in the incremental distribution network. The unbalanced power generation missing amount ΔE of the incremental distribution network in the period T is L

[0117]

[0118] In the formula, G is the maximum value of the unbalanced power generation missing in the incremental distribution network after energy storage regulation; 0 is the maximum controllable power generation of the incremental distribution network in period T, P Gn,j is the rated power of the jth controllable power supply; G is the power generation of the controllable power supply after the controllable power supply reduces the unbalanced power generation loss;

[0119] 5) Calculation of evaluation index of incremental distribution network power balance margin

[0120] ①Positive reserve power E out

[0121]

[0122] In the formula, is the minimum unbalanced power generation surplus of the incremental distribution network in period T, A s,t+T,min is the minimum power storage at the end of period T;

[0123] ②Negative reserve power E in

[0124]

[0125] In the formula, is the minimum unbalanced power generation missing quantity of the incremental distribution network in period T, A e,t+T,min is the minimum amount of electricity that can be stored in the incremental distribution network at the end of period T;

[0126] ③ Unbalanced power generation surplus E g

[0127]

[0128] In the formula, is the maximum unbalanced power generation surplus that may occur in the incremental distribution network in the next cycle T;

[0129] ④ Unbalanced power generation missing electricity E L

[0130] E L =ΔE L (11)

[0131] Among the above four evaluation indicators, positive reserve power and negative reserve power are used to describe the source-load characteristics of the incremental distribution network in the next cycle T, and unbalanced generation surplus power and unbalanced generation missing power are used to describe the operating status of the incremental distribution network in the next stage.

[0132] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A method for evaluating the balance margin of incremental distribution network electricity for scheduling plan, characterized in that: The following steps are involved: (1) Define the evaluation index of the incremental distribution network power balance margin Within a planning period T, the incremental distribution network, without external power support and on the premise of meeting its own load demand, has a power balance margin as a whole, which can be described by the following four indicators: Positive reserve power E out , Negative reserve power E in 、Unbalanced power generation surplus E g 、Unbalanced power generation missing amount E L , the specific definitions of each indicator are as follows: Positive reserve power E out : The maximum amount of electricity that the incremental distribution network can provide to the outside world within a planning period T while meeting its own load demand. The relevant variables include the minimum value of the unbalanced power generation surplus in the incremental distribution network, the minimum energy storage capacity, and the remaining power generation of the controllable power source; Negative reserve power E in : In a planning period T, the incremental distribution network can absorb the maximum amount of externally injected electricity. The relevant variables include the remaining storage space and the minimum unbalanced generation missing electricity. Unbalanced power generation surplus E g : The maximum surplus power generation that cannot be absorbed by the internal load and storage energy of the incremental distribution network within a planning period T; Unbalanced power generation missing amount E L : The maximum missing power generation caused by insufficient power generation in the incremental distribution network within a planning period T; (2) Evaluation method of power balance margin of incremental distribution network 1) Power balance margin state vector Assume that the state vector of the power balance margin is x, then the state x of the power balance margin at time t is t It is expressed as: x t =[A s,t ,TO e,t ,AND RaR,t ,AND LaR,t ] x t ∈Ω (1) Where, Ω is the incremental distribution network power balance margin state matrix, A s,t A is the amount of energy stored in the incremental distribution network at time t, e,t is the chargeable amount of energy storage in the incremental distribution network at time t, E RaR,t is the risk reserve power at time t, that is, the surplus power of the incremental distribution network under the confidence level β within the period T; E LaR,t is the risk power shortage at time t, that is, the power shortage of the incremental distribution network under the confidence level β within the period T; E RaR,t and E LaR,t The calculation formula is as follows: Where N is the number of sampling points in period T, τ is the sampling interval, and N0 is the risk reserve R aR The sampling point corresponding to 0, N 01 The next sampling point is the one corresponding to the sampling point where the risk reserve is equal to 0; The constraints of the power balance margin at time t are as follows: A s,t +A e,t ≤A (3) Where A is the difference between the maximum and minimum storage capacity of the energy storage device; First, the balance margin of electricity is calculated when only the energy storage device is considered, and the unbalanced risk electricity ΔE is used to measure it. RaR Subtract the risk of power shortage E LaR , the calculation formula is as follows: ΔE=E RaR -E LaR (4) 2) State matrix partitioning According to the unbalanced risk power ΔE and the stored power A in the incremental distribution network at time t s,t , the chargeable amount of energy stored in the incremental distribution network at time t A e,t The value of , divides the state matrix of the power balance margin into 12 sub-states as follows: ⑴ΔE≥0,A e,t ≥E RaR,t ,A s,t ≥E LaR,t ⑵ΔE≥0,A e,t ≥E RaR,t ,A s,t <E LaR,t ⑶ΔE≥0,ΔE≤A e,t <E RaR,t ,A s,t ≥E LaR,t ⑷ΔE≥0,ΔE≤A e,t <E RaR,t ,A s,t <E LaR,t ⑸ΔE≥0,A e,t <ΔE,A s,t ≥E LaR,t ⑹ΔE≥0,A e,t <ΔE,A s,t <E LaR,t ⑺ΔE<0,A s,t ≥E LaR,t ,A e,t ≥E RaR,t ⑻ΔE<0,A s,t ≥E LaR,t ,A e,t <E RaR,t ⑼ΔE<0,▕ΔE▏≤A s,t <E LaR,t ,A e,t ≥E RaR,t ⑽ΔE<0,▕ΔE▏≤A s,t <E LaR,t ,A e,t <E RaR,t ⑾ΔE<0,A s,t <▕ΔE▏,A e,t ≥E RaR,t ⑿ΔE<0,A s,t <▕ΔE▏,A e,t <E RaR,t 3) Calculation of power balance margin only taking into account energy storage devices Calculate the power balance margin state vector x when only the energy storage device is considered t Unbalanced generation surplus in different subspaces Unbalanced power generation and missing electricity The amount of electricity stored at the end of the cycle is A s,t+T 、The amount of electricity that can be stored at the end of the cycle is A e,t+T , these four values ​​characterize the ability of the energy storage device to smooth out unbalanced power; According to the state matrix partitioning method, the power balance margin evaluation index at time t can be calculated as follows: (1) A s,t+T =A s,t +ΔE,A e,t+T =[A e,t -ΔE] (2) A s,t+T =[A s,t +ΔE,E RaR,t ],A e,t+T =[A s,t -E RaR,t ,A e,t -ΔE](3) A s,t+T =[A-E LaR,t ,A s,t +ΔE],A e,t+T =[A e,t -ΔE,E LaR ](4) A s,t+T =[A-E LaR,t ,E RaR,t ],A e,t+T =[A-E RaR,t ,E LaR,t ] (5) THE s,t+T =[AE LaR,t ,A],A e,t+T =[0,E LaR,t ] (6) THE s,t+T =[AE LaR,t ,A],A e,t+T =[0,E LaR,t ] (7) A s,t+T =A s,t -|ΔE|,A e,t+T =A e,t +|ΔE| (8) A s,t+T =[A-E LaR,t ,A s,t -|ΔE]|,A e,t+T =[A e,t +|ΔE|,E LaR,t ] (9) A s,t+T =[A s,t -|ΔE|,E RaR,t ],A e,t+T =[A-E RaR,t ,A e,t +|ΔE|] (10) TO s,t+T =[AE LaR,t ,AND RaR,t ],TO e,t+T =[AE RaR,t ,AND LaR,t ] (11) THE s,t+T =[0,E RaR,t ],THE e,t+T =[AE RaR,t ,THE] (12) THE s,t+T =[0,E RaR,t ],THE e,t+T =[AE RaR,t ,THE] 4) Calculation of power balance margin taking into account controllable power supply The controllable power source is the photovoltaic and wind power generation system in the incremental distribution network. The unbalanced power generation missing amount ΔE of the incremental distribution network in the period T is L In the formula, G is the maximum value of the unbalanced power generation missing in the incremental distribution network after energy storage regulation; 0 is the maximum controllable power generation of the incremental distribution network in period T, P Gn,j is the rated power of the jth controllable power supply; G is the power generation of the controllable power supply after the controllable power supply reduces the unbalanced power generation loss; 5) Calculation of evaluation index of incremental distribution network power balance margin ①Positive reserve power E out In the formula, is the minimum unbalanced power generation surplus of the incremental distribution network in period T, A s,t+T,min is the minimum power storage at the end of period T; ②Negative reserve power E in In the formula, is the minimum unbalanced power generation missing quantity of the incremental distribution network in period T, A e,t+T,min is the minimum amount of electricity that can be stored in the incremental distribution network at the end of period T; ③ Unbalanced power generation surplus E g In the formula, is the maximum unbalanced power generation surplus that may occur in the incremental distribution network in the next cycle T; ④ Unbalanced power generation missing quantity E L E L =ΔE L (11) Among the above four evaluation indicators, positive reserve power and negative reserve power are used to describe the source-load characteristics of the incremental distribution network in the next cycle T, and unbalanced generation surplus power and unbalanced generation missing power are used to describe the operating status of the incremental distribution network in the next stage.

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