220 kilovolt transformer substation capacity expansion scheme determination method and system considering power supply capability

Abstract

The invention discloses a 220 kilovolt transformer substation capacity expansion scheme determination method considering power supply capability. The method comprises the following steps: acquiring data information of a target power system; calculating the load rate of each 220kV transformer substation in the target power system after the fault of the maximum-capacity main transformer N-1; determining the capacity expansion demand of each 220kV transformer substation and the capacity demand of a main transformer in the target power system; determining a plurality of capacity expansion schemes and calculating corresponding comprehensive evaluation coefficients; and determining a final 220kV transformer substation capacity expansion scheme according to the comprehensive evaluation coefficient. The invention also discloses a system for realizing the 220 kilovolt transformer substation capacity expansion scheme determination method considering the power supply capability. According to the method, the 220 kilovolt transformer substation capacity expansion scheme considering the power supply capacity can be determined, the reliability is higher, the accuracy is better, and the scheme is more scientific and reasonable.

Description

Technical Field

[0001] The present invention belongs to the field of electrical automation, and in particular relates to a method and system for determining a 220 kV substation expansion plan taking power supply capacity into consideration. Background Art

[0002] With the development of economy and technology and the improvement of people's living standards, electricity has become an indispensable secondary energy source in people's production and life, bringing endless convenience to people's production and life. Therefore, ensuring the stable and reliable supply of electricity has become one of the most important tasks of the power system.

[0003] At present, due to the development of grid load, the load rate of 220 kV substations in the power system is relatively high under normal operation, and the load pressure of 220 kV substations is relatively large. Moreover, when the main transformer N-1 of the 220 kV substation fails, even if the load transfer of the lower-level grid is considered, the remaining main transformers of the 220 kV substation may still be overloaded. This situation has greatly affected the safe and stable operation of the power system.

[0004] Therefore, it is of great significance to expand the capacity of 220 kV substations. However, the current expansion plans for 220 kV substations are all formulated by power system staff based on the short-term and long-term planning plans of the power grid. However, this method does not take into account the actual situation of 220 kV substations, so its reliability and accuracy are poor. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for determining a 220 kV substation expansion plan that is highly reliable, accurate and scientifically reasonable and takes power supply capacity into consideration.

[0006] A second object of the present invention is to provide a system for implementing the method for determining a 220 kV substation expansion plan that takes power supply capacity into consideration.

[0007] The method for determining a 220 kV substation expansion plan considering power supply capacity provided by the present invention comprises the following steps:

[0008] S1. Obtain data information of the target power system;

[0009] S2. According to the data information obtained in step S1, the load rate of each 220 kV substation in the target power system after the failure of the maximum capacity main transformer N-1 is calculated;

[0010] S3. According to the load rate obtained in step S2, determine the expansion demand and main transformer capacity demand of each 220 kV substation in the target power system;

[0011] S4. Determine several expansion plans based on the data information and parameter information of the 220 kV substation determined in step S3;

[0012] S5. Calculate the comprehensive evaluation coefficient of each expansion plan according to the expansion plan obtained in step S4;

[0013] S6. Determine the final 220 kV substation expansion plan based on the comprehensive evaluation coefficients of each expansion plan obtained in step S5.

[0014] The step S2 of calculating the load rate of each 220 kV substation in the target power system after the maximum capacity main transformer N-1 fails according to the data information obtained in the step S1 specifically includes the following steps:

[0015] The following formula is used to calculate the rated capacity S of the remaining transformers in a 220 kV substation after the rated maximum capacity main transformer N-1 fails: total,N-1 :

[0016]

[0017] Where S i is the rated capacity of the ith main transformer in the 220 kV substation; n is the number of main transformers in the 220 kV substation; max{S1,S2,...,S n} represents the maximum rated capacity of each main transformer in a 220 kV substation;

[0018] The following formula is used to calculate the load rate β of the 220 kV substation after the rated maximum capacity main transformer N-1 fails, taking into account the load transferred from the lower power grid:

[0019]

[0020] Where P 0,max is the maximum load of a 220 kV substation in normal operation; P trans It is the transferable load of the lower-level power grid.

[0021] The step S3, according to the load rate obtained in step S2, determines the capacity expansion requirements and main transformer capacity requirements of each 220 kV substation in the target power system, and specifically includes the following steps:

[0022] According to the load rate β of the 220 kV substation, the capacity expansion demand and main transformer capacity demand of the 220 kV substation are determined by the following rules:

[0023] If β < 100%, it is determined that the 220 kV substation does not need to be expanded;

[0024] If β ≥ 100%, it is determined that the 220 kV substation needs to be expanded and the main transformer needs to have expanded capacity.

[0025] Step S4, according to the data information determined in step S3 and the parameter information of the 220 kV substation, determines several capacity expansion plans, which specifically includes the following steps:

[0026] The number of main transformers in a 220 kV substation is set to be less than or equal to 3, and the capacity specifications of the main transformers in a 220 kV substation are 120,000 kVA, 180,000 kVA and 240,000 kVA;

[0027] Scenario 1 - 220 kV substation with 1 main transformer:

[0028] The first expansion plan: add one main transformer;

[0029] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 1,supply :

[0030] P 1,supply =min{S expand,capacity ,S1}

[0031] Where S expand,capacity is the capacity of a newly added main transformer; S1 is the capacity of the existing main transformer of the 220 kV substation;

[0032] Scenario 2 - 220 kV substation with 2 main transformers:

[0033] (1) When (β-1)S total,N-1 ≥0 and S1=S2, the expansion plan includes the second expansion plan and the third expansion plan:

[0034] The second expansion plan: add one more main transformer;

[0035] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 2,supply :

[0036] P 2,supply =min{S expand,capacity ,S1,S2}

[0037] Where S expand,capacity is the capacity of a newly added main transformer; S1 is the capacity of the first main transformer currently in the 220 kV substation; S2 is the capacity of the second main transformer currently in the 220 kV substation;

[0038] The third expansion plan: replace the existing two main transformers with larger capacity main transformers;

[0039] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 3,supply :

[0040] P 3,supply =S replaced -min{S1,S2}

[0041] Where S replaced The main transformer capacity of the 220 kV substation after the main transformer is replaced;

[0042] (2) When (β-1)S total,N-1 ≤6 and S1≠S2, the expansion plans include the fourth expansion plan and the fifth expansion plan:

[0043] The fourth expansion plan: replace the existing two main transformers with smaller ones with larger ones;

[0044] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 4,supply :

[0045] P 4,supply =min{S 1-replaced ,S 2-replaced}-min{S1,S2}

[0046] Where S 1-replaced and S 2-replaced The capacity of the two main transformers of the replaced 220 kV substation;

[0047] The fifth expansion plan: add one more main transformer;

[0048] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 5,supply :

[0049] P 5,supply =min{max{S1,S2},S expand,capacity}

[0050] Where max{S1,S2} represents the capacity value of the main transformer with larger capacity among the two existing main transformers;

[0051] (3) When (β-1)S total,N-1 >6 and S1≠S2, the expansion plans include the sixth expansion plan and the seventh expansion plan:

[0052] The sixth expansion plan: add one more main transformer;

[0053] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 6,supply :

[0054] P 6,supply =min{max{S1,S2},S expand,capacity}

[0055] Where max{S1,S2} represents the capacity value of the main transformer with larger capacity among the two existing main transformers;

[0056] The seventh expansion plan: replace the existing two main transformers with larger capacity main transformers;

[0057] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 7,supply :

[0058] P 7,supply =min{S 1-replaced ,S 2-replaced}-min{S1,S2}

[0059] Where S 1-replaced and S 2-replaced The capacity of the two main transformers of the replaced 220 kV substation;

[0060] Scenario 3 - 220 kV substation with 3 main transformers:

[0061] (1) When (β-1)S total,N-1 ≥0 and the capacities of the three main transformers are all equal, the capacity expansion plans include the eighth capacity expansion plan and the ninth capacity expansion plan:

[0062] The eighth expansion plan: add one main transformer;

[0063] The power supply capacity increase value P of the 220 kV substation is calculated 8,supply P 8,supply =S expand,capacity ;

[0064] The ninth expansion plan: replace the existing three main transformers with larger capacity main transformers;

[0065] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 9,supply :

[0066] P 9,supply =S replaced -S now

[0067] Where S replaced The capacity and S of the two main transformers of the 220 kV substation after the main transformer is replaced. now To replace the capacity of the two main transformers of the 220 kV substation before the main transformer;

[0068] (2) When (β-1)S total,N-1 When ≤6 and the capacities of the three main transformers are not completely equal, the capacity expansion plans include the tenth capacity expansion plan and the eleventh capacity expansion plan:

[0069] The tenth capacity expansion plan: among the three main transformers, replace the main transformer with the smallest capacity with a main transformer with a larger capacity;

[0070] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 10,supply :

[0071] P 10,supply =(S replaced -max{S 1-replace ,S 2-replace ,S 3-replace})-(S now -max{S1,S2,S3})

[0072] Where S 1-replace ,S 2-replace ,S 3-replace They are the capacity and S of the three main transformers of the 220 kV substation after the main transformer is replaced. now To replace the capacity of the three main transformers of the 220 kV substation before the main transformer;

[0073] Eleventh expansion plan: add one more main transformer;

[0074] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 11,supply :

[0075] P 11,supply =min{max{S1,S2,S3},S expand,capacity}

[0076] Where max{S1, S2, S3} represents the capacity of the main transformer with the largest capacity among the existing three main transformers;

[0077] (3) When (β-1)S total,N-1 >6 and the capacities of the three main transformers are not completely equal, the capacity expansion plans include the twelfth and thirteenth expansion plans:

[0078] The twelfth expansion plan: among the three main transformers, the two with smaller capacity will be replaced with main transformers with larger capacity;

[0079] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 12,supply :

[0080] P12,supply =(S replaced -max{S 1-replace ,S 2-replace ,S 3-replace})-(S now -max{S1,S2,S3})

[0081] Where S 1-replace ,S 2-replace ,S 3-replace They are the capacity and S of the three main transformers of the 220 kV substation after the main transformer is replaced. now To replace the capacity of the three main transformers of the 220 kV substation before the main transformer;

[0082] Thirteenth expansion plan: add one more main transformer;

[0083] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 13,supply :

[0084] P 13,supply =min{max{S1,S2,S3},S expand,capacity}

[0085] In the formula, max{S1, S2, S3} represents the capacity value of the main transformer with the largest capacity among the existing three main transformers.

[0086] Step S5, according to the expansion plan obtained in step S4, calculates the comprehensive evaluation coefficient of each expansion plan, which specifically includes the following steps:

[0087] The comprehensive evaluation coefficient δ of each expansion plan is calculated using the following formula:

[0088]

[0089] Where M k,i,j is the investment value of expanding the jth capacity main transformer of the ith main transformer of the 220 kV substation under the kth capacity demand plan; x i,j is a binary variable indicating whether the i-th main transformer of the 220 kV substation adopts the j-th capacity main transformer, and x i,j =1 means that the i-th main transformer of the 220 kV substation adopts the j-th capacity main transformer, x i,j =0 means that the i-th main transformer of the 220 kV substation does not use the j-th capacity main transformer; P k,supply is the power supply capacity improvement value corresponding to the kth expansion plan; M' is the other investment cost brought by expanding the capacity of the main transformer; ε kis the power supply safety margin after the failure of the largest main transformer capacity transformer N-1 of the 220 kV substation after expansion according to the kth expansion plan, and S' i is the capacity of the i-th main transformer in the 220 kV substation after expansion according to the k-th expansion plan, and N is the number of main transformers in the 220 kV substation after expansion according to the k-th expansion plan.

[0090] Step S6, according to the comprehensive evaluation coefficients of the various expansion plans obtained in step S5, determines the final 220 kV substation expansion plan, which specifically includes the following steps:

[0091] According to the comprehensive evaluation coefficients of the various expansion plans obtained in step S5, the expansion plan corresponding to the minimum comprehensive evaluation coefficient δ is selected as the final 220 kV substation expansion plan.

[0092] The present invention also provides a system for implementing the method for determining the expansion plan of a 220 kV substation taking into account the power supply capacity, comprising a data acquisition module, a load rate calculation module, a demand determination module, a plan construction module, an evaluation module and a plan determination module; the data acquisition module, the load rate calculation module, the demand determination module, the plan construction module, the evaluation module and the plan determination module are connected in series in sequence; the data acquisition module is used to acquire data information of the target power system, and upload the data information to the load rate calculation module; the load rate calculation module is used to calculate the load rate of each 220 kV substation in the target power system after the maximum capacity main transformer N-1 fails according to the received data information and the acquired data information, and upload the data information to the demand determination module; the demand determination module The determination module is used to determine the capacity expansion demand and main transformer capacity demand of each 220 kV substation in the target power system according to the received data information and the obtained load rate, and upload the data information to the solution construction module; the solution construction module is used to determine several capacity expansion plans according to the received data information, the determined data information and the parameter information of the 220 kV substation, and upload the data information to the evaluation module; the evaluation module is used to calculate the comprehensive evaluation coefficient of each capacity expansion plan according to the received data information and the obtained capacity expansion plan, and upload the data information to the solution determination module; the solution determination module is used to determine the final 220 kV substation capacity expansion plan according to the received data information and the obtained comprehensive evaluation coefficients of each capacity expansion plan.

[0093] The method and system for determining a 220 kV substation expansion plan taking into account the power supply capacity provided by the present invention evaluates the power supply capacity of the 220 kV substation based on the load rate, and constructs a corresponding expansion plan according to the evaluation result and the existing parameter information of the 220 kV substation, and evaluates the expansion plan. Therefore, the present invention can not only realize the determination of the 220 kV substation expansion plan taking into account the power supply capacity, but also has higher reliability, better accuracy, and a more scientific and reasonable plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Figure 1 The figure is a schematic diagram of the method flow of the present invention.

[0095] Figure 2 Schematic diagram of the functional modules of the system of the present invention. DETAILED DESCRIPTION

[0096] like Figure 1 The method flow chart of the method of the present invention is shown as follows: the method for determining the expansion plan of a 220 kV substation considering the power supply capacity disclosed in the present invention comprises the following steps:

[0097] S1. Obtain data information of the target power system;

[0098] S2. According to the data information obtained in step S1, the load rate of each 220 kV substation in the target power system after the failure of the maximum capacity main transformer N-1 is calculated; specifically, the following steps are included:

[0099] The following formula is used to calculate the rated capacity S of the remaining transformers in a 220 kV substation after the rated maximum capacity main transformer N-1 fails: total,N-1 :

[0100]

[0101] Where S i is the rated capacity of the ith main transformer in the 220 kV substation; n is the number of main transformers in the 220 kV substation; max{S1,S2,...,S n} represents the maximum rated capacity of each main transformer in a 220 kV substation;

[0102] The following formula is used to calculate the load rate β of the 220 kV substation after the rated maximum capacity main transformer N-1 fails, taking into account the load transferred from the lower power grid:

[0103]

[0104] Where P 0,max is the maximum load of a 220 kV substation in normal operation; P transIt is the transferable load of the lower-level power grid;

[0105] S3. According to the load rate obtained in step S2, determine the expansion demand and main transformer capacity demand of each 220 kV substation in the target power system; specifically comprising the following steps:

[0106] According to the load rate β of the 220 kV substation, the capacity expansion demand and main transformer capacity demand of the 220 kV substation are determined by the following rules:

[0107] If β < 100%, it is determined that the 220 kV substation does not need to be expanded;

[0108] If β ≥ 100%, it is determined that the 220 kV substation needs to be expanded and the main transformer needs to have expanded capacity;

[0109] S4. According to the data information determined in step S3 and the parameter information of the 220 kV substation, several expansion plans are determined; specifically comprising the following steps:

[0110] At present, the commonly used 220 kV substation main transformer capacities are 120,000 kVA, 180,000 kVA and 240,000 kVA. According to the actual situation of the power grid, the number of main transformers in most existing 220 kV substations is less than or equal to 3.

[0111] Therefore, the number of main transformers in a 220 kV substation is set to be less than or equal to 3, and the capacity specifications of the main transformers in a 220 kV substation are 120,000 kVA, 180,000 kVA and 240,000 kVA;

[0112] Scenario 1 - 220 kV substation with 1 main transformer:

[0113] The first expansion plan: add one main transformer;

[0114] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 1,supply :

[0115] P 1,supply =min{S expand,capacity ,S1}

[0116] Where S expand,capacity is the capacity of a newly added main transformer, which may be 12, 18 or 24; S1 is the capacity of the existing main transformer of the 220 kV substation;

[0117] Scenario 2 - 220 kV substation with 2 main transformers:

[0118] (1) When (β-1)S total,N-1 ≥0 and S1=S2, the expansion plan includes the second expansion plan and the third expansion plan:

[0119] The second expansion plan: add one more main transformer;

[0120] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 2,supply :

[0121] P 2,supply =min{S expand,capacity ,S1,S2}

[0122] Where S expand,capacity is the capacity of a newly added main transformer, which may be 12, 18 or 24; S1 is the capacity of the first main transformer currently in the 220 kV substation; S2 is the capacity of the second main transformer currently in the 220 kV substation;

[0123] The third expansion plan: replace the existing two main transformers with larger capacity main transformers;

[0124] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 3,supply :

[0125] P 3,supply =S replaced -min{S1,S2}

[0126] Where S replaced is the capacity of the main transformer of the 220 kV substation after the main transformer is replaced; the power supply capacity increase value P at this time 3,supply The value of may be 6 or 12;

[0127] (2) When (β-1)S total,N-1 ≤6 and S1≠S2, the expansion plans include the fourth expansion plan and the fifth expansion plan:

[0128] The fourth expansion plan: replace the existing two main transformers with smaller ones with larger ones;

[0129] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 4,supply :

[0130] P 4,supply =min{S 1-replaced ,S 2-replaced}-min{S1,S2}

[0131] Where S 1-replaced and S 2-replaced is the capacity of the two main transformers of the 220 kV substation after replacement; the power supply capacity increase value P 4,supply The value of may be 6 or 12;

[0132] The fifth expansion plan: add one more main transformer;

[0133] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 5,supply :

[0134] P 5,supply =min{max{S1,S2},S expand,capacity}

[0135] Where max{S1,S2} represents the capacity value of the main transformer with larger capacity among the two existing main transformers;

[0136] (3) When (β-1)S total,N-1 >6 and S1≠S2, the expansion plans include the sixth expansion plan and the seventh expansion plan:

[0137] The sixth expansion plan: add one more main transformer;

[0138] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 6,supply :

[0139] P 6,supply =min{max{S1,S2},S expand,capacity}

[0140] Where max{S1,S2} represents the capacity value of the main transformer with larger capacity among the two existing main transformers;

[0141] The seventh expansion plan: replace the existing two main transformers with larger capacity main transformers;

[0142] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 7,supply :

[0143] P 7,supply =min{S 1-replaced ,S 2-replaced}-min{S1,S2}

[0144] Where S 1-replaced and S 2-replaced is the capacity of the two main transformers of the 220 kV substation after replacement; the power supply capacity increase value P 7,supply The value of may be 6 or 12;

[0145] Scenario 3 - 220 kV substation with 3 main transformers:

[0146] (1) When (β-1)S total,N-1≥0 and the capacities of the three main transformers are all equal, the capacity expansion plans include the eighth capacity expansion plan and the ninth capacity expansion plan:

[0147] The eighth expansion plan: add one main transformer;

[0148] The power supply capacity increase value P of the 220 kV substation is calculated 8,supply P 8,supply =S expand,capacity ;

[0149] The ninth expansion plan: replace the existing three main transformers with larger capacity main transformers;

[0150] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 9,supply :

[0151] P 9,supply =S replaced -S now

[0152] Where S replaced The capacity and S of the two main transformers of the 220 kV substation after the main transformer is replaced. now The capacity of the two main transformers of the 220 kV substation before the replacement of the main transformer; the power supply capacity increase value P at this time 9,supply The value of may be 12 or 24;

[0153] (2) When (β-1)S total,N-1 When ≤6 and the capacities of the three main transformers are not completely equal, the capacity expansion plans include the tenth capacity expansion plan and the eleventh capacity expansion plan:

[0154] The tenth capacity expansion plan: among the three main transformers, replace the main transformer with the smallest capacity with a main transformer with a larger capacity;

[0155] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 10,supply :

[0156] P 10,supply =(S replaced -max{S 1-replace ,S 2-replace ,S 3-replace})-(S now -max{S1,S2,S3})

[0157] Where S 1-replace ,S 2-replace ,S 3-replace They are the capacity and S of the three main transformers of the 220 kV substation after the main transformer is replaced. nowThe capacity and power supply capacity of the three main transformers of the 220 kV substation before the main transformer is replaced; the power supply capacity increase value P 10,supply The value of may be 6 or 12;

[0158] Eleventh expansion plan: add one more main transformer;

[0159] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 11,supply :

[0160] P 11,supply =min{max{S1,S2,S3},S expand,capacity}

[0161] Where max{S1, S2, S3} represents the capacity of the main transformer with the largest capacity among the existing three main transformers;

[0162] (3) When (β-1)S total,N-1 >6 and the capacities of the three main transformers are not completely equal, the capacity expansion plans include the twelfth and thirteenth expansion plans:

[0163] The twelfth expansion plan: among the three main transformers, the two with smaller capacity will be replaced with main transformers with larger capacity;

[0164] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 12,supply :

[0165] P 12,supply =(S replaced -max{S 1-replace ,S 2-replace ,S 3-replace})-(S now -max{S1,S2,S3})

[0166] Where S 1-replace ,S 2-replace ,S 3-replace They are the capacity and S of the three main transformers of the 220 kV substation after the main transformer is replaced. now The capacity and power supply capacity of the three main transformers of the 220 kV substation before the main transformer is replaced; the power supply capacity increase value P 12,supply The possible values ​​of are 12, 18, or 24;

[0167] Thirteenth expansion plan: add one more main transformer;

[0168] The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 13,supply :

[0169] P13,supply =min{max{S1,S2,S3},S expand,capacity}

[0170] Where max{S1, S2, S3} represents the capacity of the main transformer with the largest capacity among the existing three main transformers;

[0171] S5. According to the expansion plan obtained in step S4, the comprehensive evaluation coefficient of each expansion plan is calculated; specifically, the steps include:

[0172] In actual projects, the economic benefits and long-term adaptability of 220 kV substation capacity expansion also need to be considered. Therefore, the comprehensive evaluation coefficient δ of each expansion plan is calculated using the following formula:

[0173]

[0174] Where M k,i,j is the investment value of expanding the j-th capacity main transformer of the i-th main transformer of the 220 kV substation under the k-th capacity demand plan, where the value of j is 1, 2 or 3, corresponding to 120,000 kVA capacity, 180,000 kVA capacity and 240,000 kVA capacity respectively; x i,j is a binary variable indicating whether the i-th main transformer of the 220 kV substation adopts the j-th capacity main transformer, and x i,j =1 means that the i-th main transformer of the 220 kV substation adopts the j-th capacity main transformer, x i,j =0 means that the i-th main transformer of the 220 kV substation does not use the j-th capacity main transformer; P k,supply is the power supply capacity improvement value corresponding to the kth expansion plan, and the value of k ranges from 1 to 13; M' is the other investment cost brought about by expanding the capacity of the main transformer; ε k is the power supply safety margin after the failure of the largest main transformer capacity transformer N-1 of the 220 kV substation after expansion according to the kth expansion plan, and S' i is the capacity of the i-th main transformer in the 220 kV substation after expansion according to the k-th expansion plan, and N is the number of main transformers in the 220 kV substation after expansion according to the k-th expansion plan;

[0175] For actual projects, while ensuring the investment in increasing the power supply capacity of every 10,000 kW, the substation needs to have better long-term adaptability after capacity expansion. This long-term adaptability is reflected in the power supply margin ε after the maximum main transformer capacity transformer N-1 after the capacity expansion of the 220 kV substation. k ;

[0176] S6. According to the comprehensive evaluation coefficients of the various expansion plans obtained in step S5, determine the final 220 kV substation expansion plan; specifically comprising the following steps:

[0177] According to the comprehensive evaluation coefficients of the various expansion plans obtained in step S5, the expansion plan corresponding to the minimum comprehensive evaluation coefficient δ is selected as the final 220 kV substation expansion plan.

[0178] The method of the present invention is further described below in conjunction with an embodiment:

[0179] The effectiveness and adaptability of the proposed method are analyzed by taking an actual 220 kV substation in a certain province as an example.

[0180] Substation A has two 220 kV main transformers with a transformer capacity of 2×180,000 kVA. The maximum load in 2023 is 301,900 kW, and the load rate α=83.86%. After the main transformer N-1, the remaining capacity of the substation main transformer S total,N-1 =180,000 kVA.

[0181] After the failure of the largest main transformer N-1 in the 220 kV substation, the load rate of the substation β=117.15%≥100% considering the load transferred from the lower power grid. Therefore, the main transformer capacity demand scenario analysis of the substation is scenario 2. In this scenario:

[0182] (β-1)S total,N-1 =3.09≥0

[0183] S1=S2=180,000 kVA

[0184] S sub,require =180,000 kVA

[0185] When the first option "adding a new transformer" is adopted, the power supply capacity of the 220 kV substation is increased to: P supply =min{S expand,capacity ,S1,S2}=180,000 kW;

[0186] When the second option "replacing two transformers with larger capacity" is adopted, the power supply capacity of the 220 kV substation is increased to: P supply =60,000 kilowatts;

[0187] From the above analysis, we can know that:

[0188] When Plan 1 is adopted, the capacity of the main transformer will be expanded to 180,000 kVA.

[0189]

[0190] According to the actual project, the investment in expanding a 180,000 kVA main transformer is about M1,i,2 = 22 million yuan, the investment in expanding a 240,000 kVA main transformer is about M 1i3 = 33 million yuan. Therefore, the comprehensive evaluation index of benefits and long-term adaptability is:

[0191]

[0192] When adopting the second option, two larger capacity transformers are replaced, with a transformer capacity of 240,000 kVA;

[0193]

[0194] Combined with the actual construction situation of the 220 kV substation, the substation does not have good construction conditions for the time being when adopting Plan 1, that is, the other cost investment for expanding the capacity of the substation main transformer is relatively large M1'>>M2'. After calculating the comprehensive evaluation index, δ2<δ1 is obtained. Therefore, Plan 2 is selected as the expansion plan for the capacity of the main transformer A of the substation.

[0195] Substation B has three 220 kV main transformers with a transformer capacity of 2×12+1×180,000 kVA. The maximum load in 2023 is 349,900 kW, and the load rate α=83.31%. After the main transformer N-1, the remaining capacity of the substation main transformer S total,N-1 =240,000 kVA.

[0196] After the failure of the largest main transformer N-1 in the 220 kV substation, the load rate of the substation β=109.25%≥100% considering the load transferred from the lower power grid. Therefore, the main transformer capacity demand scenario analysis of the substation is scenario 3. In this scenario:

[0197] 0<(β-1)S total,N-1 =2.22<6

[0198] S sub,require =60,000 kVA

[0199] When the existing small-capacity main transformer is replaced with a 240,000 kVA main transformer, the power supply capacity of the substation is increased by P supply = 60,000 kilowatts; then

[0200]

[0201] If a new 180,000 kVA main transformer is added in Plan 2, the power supply capacity of the 220 kV substation will be increased by P after expansion. supply =min{max{S1,S2,S3},S expand,capacity}=180,000 kilowatts; then

[0202]

[0203] Combined with the actual construction situation of the 220 kV substation, the substation does not have good construction conditions when adopting Plan ②, that is, the other cost investment for expanding the capacity of the substation main transformer is relatively large M1'CM2'. After calculating the comprehensive evaluation index, it is obtained that δ2>δ1, so Plan 1 is selected as the expansion plan for the capacity of the main transformer A of the substation.

[0204] The scheme of the present invention can consider the improvement of the power supply capacity of 220 kV substations, calculate the capacity requirements in different scenarios, and evaluate the capacity demand calculation methods in different scenarios. Combined with the actual project and the construction of 220 kV substations, the cost of substation capacity expansion is considered, and a comprehensive evaluation index of benefits and long-term adaptability is proposed, and then a capacity expansion plan suitable for 220 kV substations is selected. This method provides a reasonable analysis basis for power grid planning and operation personnel, and at the same time combines the actual project, which is of great significance, and is conducive to improving the safe and stable operation level of the power grid and improving the power supply capacity of regional 220 kV substations.

[0205] like Figure 2 The functional module diagram of the system of the present invention is shown as follows: the system disclosed in the present invention for realizing the method for determining the expansion plan of a 220 kV substation taking into account the power supply capacity comprises a data acquisition module, a load rate calculation module, a demand determination module, a plan construction module, an evaluation module and a plan determination module; the data acquisition module, the load rate calculation module, the demand determination module, the plan construction module, the evaluation module and the plan determination module are connected in series in sequence; the data acquisition module is used to acquire data information of the target power system and upload the data information to the load rate calculation module; the load rate calculation module is used to calculate the load rate of each 220 kV substation in the target power system after the maximum capacity main transformer N-1 fails according to the received data information and the acquired data information, and upload the data information to the demand Determination module; the demand determination module is used to determine the expansion demand and main transformer capacity demand of each 220 kV substation in the target power system according to the received data information and the obtained load rate, and upload the data information to the solution construction module; the solution construction module is used to determine several expansion plans according to the received data information, the determined data information and the parameter information of the 220 kV substation, and upload the data information to the evaluation module; the evaluation module is used to calculate the comprehensive evaluation coefficient of each expansion plan according to the received data information and the obtained expansion plan, and upload the data information to the solution determination module; the solution determination module is used to determine the final 220 kV substation expansion plan according to the received data information and the obtained comprehensive evaluation coefficients of each expansion plan.

Claims

1. A method for determining a 220 kV substation expansion plan considering power supply capacity, comprising the following steps: S1. Obtain data information of the target power system; S2. According to the data information obtained in step S1, the load rate of each 220 kV substation in the target power system after the failure of the maximum capacity main transformer N-1 is calculated; S3. According to the load rate obtained in step S2, determine the expansion demand and main transformer capacity demand of each 220 kV substation in the target power system; S4. Determine several expansion plans based on the data information and parameter information of the 220 kV substation determined in step S3; S5. Calculate the comprehensive evaluation coefficient of each expansion plan according to the expansion plan obtained in step S4; S6. Determine the final 220 kV substation expansion plan based on the comprehensive evaluation coefficients of each expansion plan obtained in step S5.

2. The method for determining a 220 kV substation expansion plan considering power supply capacity according to claim 1 is characterized in that The step S2 of calculating the load rate of each 220 kV substation in the target power system after the maximum capacity main transformer N-1 fails according to the data information obtained in the step S1 specifically includes the following steps: The following formula is used to calculate the rated capacity S of the remaining transformers in a 220 kV substation after the rated maximum capacity main transformer N-1 fails: total,N-1 : Where S i is the rated capacity of the ith main transformer in the 220 kV substation; n is the number of main transformers in the 220 kV substation; max{S1,S2,...,S n } represents the maximum rated capacity of each main transformer in a 220 kV substation; The following formula is used to calculate the load rate β of the 220 kV substation after the rated maximum capacity main transformer N-1 fails, taking into account the load transferred from the lower power grid: Where P 0,max is the maximum load of a 220 kV substation in normal operation; P trans It is the transferable load of the lower-level power grid.

3. The method for determining a 220 kV substation expansion plan considering power supply capacity according to claim 2 is characterized in that The step S3, according to the load rate obtained in step S2, determines the capacity expansion requirements and main transformer capacity requirements of each 220 kV substation in the target power system, and specifically includes the following steps: According to the load rate β of the 220 kV substation, the capacity expansion demand and main transformer capacity demand of the 220 kV substation are determined by the following rules: If β < 100%, it is determined that the 220 kV substation does not need to be expanded; If β ≥ 100%, it is determined that the 220 kV substation needs to be expanded and the main transformer needs to have expanded capacity.

4. The method for determining a 220 kV substation expansion plan considering power supply capacity according to claim 3 is characterized in that Step S4, according to the data information determined in step S3 and the parameter information of the 220 kV substation, determines several capacity expansion plans, which specifically includes the following steps: The number of main transformers in a 220 kV substation is set to be less than or equal to 3, and the capacity specifications of the main transformers in a 220 kV substation are 120,000 kVA, 180,000 kVA and 240,000 kVA; Scenario 1 - 220 kV substation with 1 main transformer: The first expansion plan: add one main transformer; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 1,supply : P 1,supply =min{S expand,capacity ,S1} Where S expand,capacity is the capacity of a newly added main transformer; S1 is the capacity of the existing main transformer of the 220 kV substation; Scenario 2 - 220 kV substation with 2 main transformers: (1) When (β-1)S total,N-1 ≥0 and S1=S2, the expansion plan includes the second expansion plan and the third expansion plan: The second expansion plan: add one more main transformer; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 2,supply : P 2,supply =min{S expand,capacity ,S1,S2} Where S expand,capacity is the capacity of a newly added main transformer; S1 is the capacity of the first main transformer currently in the 220 kV substation; S2 is the capacity of the second main transformer currently in the 220 kV substation; The third expansion plan: replace the existing two main transformers with larger capacity main transformers; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 3,supply : P 3,supply =S replaced -min{S1,S2} Where S replaced The main transformer capacity of the 220 kV substation after the main transformer is replaced; (2) When (β-1)S total,N-1 ≤6 and S1≠S2, the expansion plans include the fourth expansion plan and the fifth expansion plan: The fourth expansion plan: replace the existing two main transformers with smaller ones with larger ones; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 4,supply : P 4,supply =min{S 1-replaced ,S 2-replaced }-min{S1,S2} Where S 1-replaced and S 2-replaced The capacity of the two main transformers of the replaced 220 kV substation; The fifth expansion plan: add one more main transformer; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 5,supply : P 5,supply =min{max{S1,S2},S expand,capacity } Where max{S1,S2} represents the capacity value of the main transformer with larger capacity among the two existing main transformers; (3) When (β-1)S total,N-1 >6 and S1≠S2, the expansion plans include the sixth expansion plan and the seventh expansion plan: The sixth expansion plan: add one more main transformer; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 6,supply : P 6,supply =min{max{S1,S2},S expand,capacity } Where max{S1,S2} represents the capacity value of the main transformer with larger capacity among the two existing main transformers; The seventh expansion plan: replace the existing two main transformers with larger capacity main transformers; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 7,supply : P 7,supply =min{S 1-replaced ,S 2-replaced }-min{S1,S2} Where S 1-replaced and S 2-replaced The capacity of the two main transformers of the replaced 220 kV substation; Scenario 3 - 220 kV substation with 3 main transformers: (1) When (β-1)S total,N-1 ≥0 and the capacities of the three main transformers are all equal, the capacity expansion plans include the eighth capacity expansion plan and the ninth capacity expansion plan: The eighth expansion plan: add one main transformer; The power supply capacity increase value P of the 220 kV substation is calculated 8,supply P 8,supply =S expand,capacity ; The ninth expansion plan: replace the existing three main transformers with larger capacity main transformers; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 9,supply : P 9,supply =S replaced -S now Where S replaced The capacity and S of the two main transformers of the 220 kV substation after the main transformer is replaced. now To replace the capacity of the two main transformers of the 220 kV substation before the main transformer; (2) When (β-1)S total,N-1 When ≤6 and the capacities of the three main transformers are not completely equal, the expansion plans include the tenth expansion plan and the eleventh expansion plan: The tenth capacity expansion plan: among the three main transformers, replace the main transformer with the smallest capacity with a main transformer with a larger capacity; The tenth capacity expansion plan: among the three main transformers, replace the main transformer with the smallest capacity with a main transformer with a larger capacity; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 10,supply : P 10,supply =(S replaced -max{S 1-replace ,S 2-replace ,S 3-replace })-(S now -max{S1,S2,S3}) Where S 1-replace ,S 2-replace ,S 3-replace They are the capacity and S of the three main transformers of the 220 kV substation after the main transformer is replaced. now To replace the capacity of the three main transformers of the 220 kV substation before the main transformer; Eleventh expansion plan: add one more main transformer; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 11,supply : P 11,supply =min{max{S1,S2,S3},S expand,capacity } Where max{S1, S2, S3} represents the capacity of the main transformer with the largest capacity among the existing three main transformers; (3) When (β-1)S total,N-1 >6 and the capacities of the three main transformers are not completely equal, the capacity expansion plans include the twelfth and thirteenth expansion plans: The twelfth expansion plan: among the three main transformers, the two with smaller capacity will be replaced with main transformers with larger capacity; The twelfth expansion plan: among the three main transformers, the two with smaller capacity will be replaced with main transformers with larger capacity; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 12,supply : P 12,supply =(S replaced -max{S 1-replace ,S 2-replace ,S 3-replace })-(S now -max{S1,S2,S3}) Where S 1-replace ,S 2-replace ,S 3-replace They are the capacity and S of the three main transformers of the 220 kV substation after the main transformer is replaced. now To replace the capacity of the three main transformers of the 220 kV substation before the main transformer; Thirteenth expansion plan: add one more main transformer; The power supply capacity increase value P of the 220 kV substation is calculated using the following formula: 13,supply : P 13,supply =min{max{S1,S2,S3},S expand,capacity } In the formula, max{S1, S2, S3} represents the capacity value of the main transformer with the largest capacity among the existing three main transformers.

5. The method for determining a 220 kV substation expansion plan considering power supply capacity according to claim 4 is characterized in that Step S5, according to the expansion plan obtained in step S4, calculates the comprehensive evaluation coefficient of each expansion plan, which specifically includes the following steps: The comprehensive evaluation coefficient δ of each expansion plan is calculated using the following formula: Where M k,i,j is the investment value of expanding the jth capacity main transformer of the ith main transformer of the 220 kV substation under the kth capacity demand plan; x i,j is a binary variable indicating whether the i-th main transformer of the 220 kV substation adopts the j-th capacity main transformer, and x i,j =1 means that the i-th main transformer of the 220 kV substation adopts the j-th capacity main transformer, x i,j =0 means that the i-th main transformer of the 220 kV substation does not use the j-th capacity main transformer; P k,supply is the power supply capacity improvement value corresponding to the kth expansion plan; M' is the other investment cost caused by expanding the capacity of the main transformer; ε k is the power supply safety margin after the failure of the largest main transformer capacity transformer N-1 of the 220 kV substation after expansion according to the kth expansion plan, and S' i is the capacity of the i-th main transformer in the 220 kV substation after expansion according to the k-th expansion plan, and N is the number of main transformers in the 220 kV substation after expansion according to the k-th expansion plan.

6. The method for determining a 220 kV substation expansion plan considering power supply capacity according to claim 5, characterized in that Step S6, according to the comprehensive evaluation coefficients of the various expansion plans obtained in step S5, determines the final 220 kV substation expansion plan, which specifically includes the following steps: According to the comprehensive evaluation coefficients of the various expansion plans obtained in step S5, the expansion plan corresponding to the minimum comprehensive evaluation coefficient δ is selected as the final 220 kV substation expansion plan.

7. A system for implementing the method for determining a 220 kV substation expansion plan considering power supply capacity as described in any one of claims 1 to 6, characterized in that It includes a data acquisition module, a load rate calculation module, a demand determination module, a solution construction module, an evaluation module and a solution determination module; the data acquisition module, the load rate calculation module, the demand determination module, the solution construction module, the evaluation module and the solution determination module are connected in series in sequence; the data acquisition module is used to acquire data information of the target power system and upload the data information to the load rate calculation module; The load rate calculation module is used to calculate the load rate of each 220 kV substation in the target power system after the maximum capacity main transformer N-1 fails according to the received data information and the acquired data information, and upload the data information to the demand determination module; the demand determination module is used to determine the capacity expansion demand and the main transformer capacity demand of each 220 kV substation in the target power system according to the received data information and the obtained load rate, and upload the data information to the solution construction module; the solution construction module is used to determine several capacity expansion plans according to the received data information, the determined data information and the parameter information of the 220 kV substation, and upload the data information to the evaluation module; The evaluation module is used to calculate the comprehensive evaluation coefficient of each expansion plan according to the received data information and the obtained expansion plan, and upload the data information to the plan determination module; The solution determination module is used to determine the final 220 kV substation expansion plan based on the received data information and the comprehensive evaluation coefficients of various expansion plans.

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