A design method for transmission fee considering high proportion of distributed generation access

Abstract

The present invention discloses a method for designing a transmission fee that takes into account a high proportion of distributed power access, and relates to the field of fee design in the power market. Specifically, it includes: setting a power supply guarantee coefficient, stipulating the fee collection situation in different scenarios; obtaining shared network data, calculating the theoretical transmission and distribution price based on the price forward method, and obtaining the transmission fee; comparing the power generation of distributed power sources with the agreed power volume, and determining the fees that users need to bear; calculating the power supply reliability of distributed power sources according to the degree of power balance at each time point, and obtaining the power supply guarantee fee paid by distributed power sources, and determining the fees that distributed power sources need to bear. The present invention can ensure the recovery of power grid costs, and distributed power sources and power users will bear the responsibility for power stability fairly, which is conducive to promoting distributed power generation and improving the level of safe and stable operation. At the same time, it can improve the electricity consumption behavior of power users and increase their enthusiasm for participating in the consumption of new energy.

Description

Technical Field

[0001] The present invention relates to the field of fee design in the power market, and in particular to a method for designing a transmission fee taking into account access of a high proportion of distributed power sources. Background Art

[0002] A large number of new user-side entities, led by distributed power generation (DGs), are emerging, integrating production and consumption, and possessing legal power sales qualifications. Distributed trading models, characterized by numerous participants and low barriers to entry for individual power transactions, are gradually becoming a new trading trend. At the same time, due to the fragmented and difficult-to-control nature of various user-side entities, users are participating in distributed trading through aggregated methods such as load aggregators and microgrids, impacting the traditional electricity market. Against this backdrop, key questions, such as the scale of costs grid companies must bear, how to manage the costs necessary to ensure the safe and stable operation of the power system, and how to coordinate efforts across markets, remain largely unresolved, lacking comprehensive and objective quantification or systematic and in-depth understanding. This makes it difficult to specifically incorporate these costs into transmission and distribution prices.

[0003] While significant progress has been made in establishing transmission and distribution prices, numerous challenges remain, particularly the impact of distributed power trading on transmission and distribution prices, which urgently need to be addressed. On the one hand, transmission and distribution prices for each voltage level fail to reflect the true costs of that voltage level. On the other hand, for distributed power trading entities and users, the grid company's minimum power supply guarantee responsibility and obligation is unlimited. Transmission fees are fees charged by grid companies to distributed power sources connected to the grid to compensate for grid operation and maintenance costs and safety risk. Too low a fee could result in the grid failing to recoup the investment in securing distributed power sources, while too high a fee could exacerbate the financial difficulties of distributed power sources. Current policy requires that transmission fees be charged based on transmission and distribution price differentials. However, current provincial grid transmission and distribution prices incorporate policy-driven cross-subsidies. When the transmission and distribution prices of two voltage levels are subtracted, these cross-subsidies are directly offset, meaning that grid companies cannot cover their operating costs and reasonable profits through transmission fees. At the same time, the integration of a high proportion of distributed power generation requires the power system to have greater flexibility and adjustability. The power system needs to have sufficient adjustment capabilities to cope with the fluctuations in the output of distributed power generation to balance supply and demand. However, the current transmission fee mechanism cannot enable the power grid to recover its power supply guarantee costs. Therefore, it is necessary to improve the current transmission fee mechanism and propose a reasonable transmission method for transmission and distribution fees to mobilize the enthusiasm of new users and take into account the interests of power grid companies. Summary of the Invention

[0004] In order to solve the problem that when a high proportion of distributed power sources are connected to the power system, the power system's regulation capacity is insufficient, resulting in fluctuations in the output of distributed power sources and an inability to balance supply and demand well, and the grid fee mechanism is unable to enable the power grid to recover the power to ensure power supply balance, the present invention provides a grid fee design method that takes into account the access of a high proportion of distributed power sources.

[0005] The present invention provides a method for designing a transmission fee that takes into account a high proportion of distributed power generation access. This method separates cross-subsidy from transmission and distribution costs, restores the transmission and distribution cost attributes of the transmission fee, avoids differences in transmission fees caused by different cross-subsidy situations, reflects the actual distribution network absorption cost, and promotes the participation of distributed renewable energy in distributed transactions.

[0006] The present invention is achieved through the following technical solution: a method for designing a transmission fee taking into account a high proportion of distributed power supply access, comprising the following steps:

[0007] S1: Set the power supply guarantee coefficient and specify the fee collection in different scenarios; the details are as follows:

[0008] For distributed power generation participating in distributed transactions, the grid can recover its investment costs by charging a grid access fee plus a power supply guarantee fee. The grid access fee refers to the theoretical transmission and distribution price of the provincial grid public network corresponding to the voltage level of the power user's access (excluding policy-based cross-subsidies), minus the theoretical transmission and distribution price of the highest voltage level involved in the distributed generation market transaction (excluding policy-based cross-subsidies).

[0009] Since there are deviations between the output forecast and load forecast of distributed power generation, this poses a challenge to the power supply guarantee of the power grid. The present invention calculates the power supply reliability by calculating the difference between the declared power generation of new energy and the actual power generation, divided by the declared power generation of new energy. The impact of the unstable output of distributed power generation on the power grid is compensated by increasing the power supply guarantee fee for distributed power generation. According to the real-time power supply reliability of distributed power generation, the power supply guarantee fee is obtained by multiplying the power difference by the cost coefficient under different power supply guarantee reliability. The formula is as follows:

[0010] (1)

[0011] (2)

[0012] Where K g For power supply reliability, Q d Reporting electricity consumption for new energy, Q g is the actual power generation of new energy, F g is the power supply guarantee fee, k g It is the reliability cost coefficient of power supply.

[0013] S2: Obtain shared network data and calculate the theoretical transmission and distribution price based on the forward price method to derive the transmission fee. First, according to the provisions of the "Provincial Power Grid Transmission and Distribution Price Pricing Method", the grid company's permitted income is the transmission and distribution network cost borne by power users. The provincial power grid public network transmission and distribution price cost calculation method is as follows:

[0014] S2-1: Calculate the shared network licensing revenue, which consists of licensing costs, licensing benefits, and taxes. The formula is as follows:

[0015] (3)

[0016] (4)

[0017] (5)

[0018] Where, Allowing income for shared networks, To allow costs, To allow income, For taxes; represents the base period allowable cost of the transmission and distribution network, represents the permitted cost of additions or subtractions to the transmission and distribution network; It represents the effective assets of the transmission and distribution network that can accrue income. represents the permitted rate of return;

[0019] S2-2: Calculate the transmission and distribution costs for each voltage level. Allowable costs are aggregated based on the amount of electricity transmitted and allocated to each voltage level. Allowable income and taxes are aggregated based on the net value of fixed assets and allocated to each voltage level. The formula is as follows:

[0020] (6)

[0021] (7)

[0022] (8)

[0023] Where, for Voltage level transmission and distribution costs, for The proportion of electricity delivered by voltage level, for Percentage of fixed assets by voltage level; for Voltage level total transmission power, for Total amount of power transmitted by voltage level; for Net value of fixed assets at voltage level, for Net value of fixed assets at voltage level;

[0024] S2-3: Calculate the permitted revenue of transmission and distribution prices at each voltage level, where the total permitted revenue of a voltage level is composed of the permitted revenue of the current voltage level and the permitted revenue transmitted from the previous voltage level;

[0025] Electricity users at different voltage levels also have varying degrees of occupancy of the transmission and distribution network. Since power flows are transferred from the high-voltage transmission and distribution network to the low-voltage transmission and distribution network, electricity users connected to the high-voltage transmission and distribution network do not use the low-voltage transmission and distribution network. However, when high-voltage electricity users transmit electricity, in addition to supplying electricity users at their own voltage level, some electricity is also transmitted to low-voltage electricity users after being stepped down by transformers. Therefore, electricity users on the low-voltage transmission and distribution network not only use the transmission and distribution network at their own voltage level, but also occupy the high-voltage transmission and distribution network.

[0026] Considering the rationality of allocating transmission and distribution network costs, electricity users at lower voltage levels should, while bearing the transmission and distribution costs of their own voltage level, also share a portion of the costs of the higher-voltage transmission and distribution network that delivers electricity to that voltage level. Therefore, when calculating the permissible revenue for transmission and distribution prices at each voltage level, it is necessary to consider the power flow transmission relationship between different voltage levels.

[0027] Based on the power flow transmission relationship between transmission and distribution networks of different voltage levels, the cost transmission relationship between power grids of different voltage levels is determined as follows: 66 kV power users share the transmission and distribution network costs of 220 kV power users; 20 kV power users share the transmission and distribution network costs of 220 kV and 66 kV power users; 10 kV power users share the transmission and distribution network costs of 220 kV, 66 kV, and 20 kV power users; 1 kV and below power users only share the transmission and distribution network costs of 10 kV power users. The formula is:

[0028] (9)

[0029] Where, for Permitted income from voltage level transmission and distribution prices, for Voltage level transmission and distribution costs, for Voltage level transmission and distribution costs, for The amount of electricity delivered by the voltage level to users of this voltage level, for Voltage level Voltage level The amount of electricity delivered by the user, for Total amount of power transmitted by voltage level;

[0030] S2-4: Calculate the transmission and distribution price for industrial and commercial users at each voltage level using the following formula:

[0031] (10)

[0032] Where, for The transmission and distribution price for industrial and commercial users with a single voltage level system is for Voltage level single system industrial and commercial users share The proportion of permitted income from power transmission and distribution at each voltage level, for Electricity consumption of industrial and commercial users with a single voltage level system;

[0033] At the same voltage level, the peak load responsibility method and the maximum load method are usually used to allocate the transmission and distribution permitted revenue to different types of power users. However, both methods will lead to a lack of fairness in the allocation results of the transmission and distribution permitted revenue. Therefore, considering the dynamic changes in the load of different types of power users in different time periods, the comprehensive load method is used to calculate the permitted revenue allocation ratio for industrial and commercial users. :

[0034] (11)

[0035] Where, 、 、 and Represents residential users, agricultural users, single-system industrial and commercial users, and two-system industrial and commercial users in The annual maximum electricity load at the time, express Voltage level electricity users The ratio of the annual maximum electricity load at a certain time to the sum of the annual maximum electricity loads of power users of this voltage level at all times;

[0036] S2-5: Calculate the two-part transmission and distribution price for industrial and commercial users at each voltage level;

[0037] (12)

[0038] (13)

[0039] (14)

[0040] (15)

[0041] Where, 、 、 They are The electricity transmission and distribution price for industrial and commercial users with two voltage levels, namely, electricity quantity, capacity and demand. 、 、 The proportion of electricity consumption, capacity and demand transmission and distribution charges of industrial and commercial users in the total transmission and distribution charges is respectively for Voltage level two-part system shared by industrial and commercial users The proportion of permitted income from power transmission and distribution at each voltage level, for The electricity consumption of industrial and commercial users with two voltage levels is for Transformer capacity for industrial and commercial users with two voltage levels, for The annual maximum electricity load of industrial and commercial users with two voltage levels.

[0042] S3: Compare the power generation of distributed power generation with the agreed power generation to determine the fees to be borne by the user; calculate the power supply reliability of distributed power generation based on the power balance degree at each time point, obtain the power supply guarantee fee paid by distributed power generation, and determine the fees to be borne by distributed power generation, as follows:

[0043] Based on the principle that the grid access fee is borne by the user and the power supply guarantee fee is borne by the distributed power generation, the scenarios for the fees paid by users and distributed power generation are divided into four situations:

[0044] Ⅰ. The power generation of distributed generation is equal to the agreed power, and the power is balanced at each time point: the user pays the full amount of power purchase transmission fee;

[0045] II. The power generation of distributed generation is equal to the agreed power, and there is a power imbalance at a certain point in time: the user pays the full amount of power purchase transmission fee; the distributed generation bears the power supply guarantee fee corresponding to the power imbalance point in time, which is calculated using formulas (1) and (2);

[0046] III. The power generation of distributed generation is less than the agreed power, and the power is balanced at each time point: the user pays the transmission fee for the actual transaction between the user and the distributed generation; the user pays the corresponding voltage level transmission and distribution price for the part of the power purchased from the grid that is less than the agreed power; the distributed generation bears the power supply guarantee fee for the power that fails to fulfill the agreement, which is calculated using formulas (1) and (2);

[0047] IV. The power generation of distributed power generation is less than the agreed power generation, and the power is unbalanced at each time point: the user pays the transmission fee for the portion of the power actually traded between the user and the distributed power generation; the user pays the corresponding voltage level transmission and distribution price for the portion of the power purchased from the grid that is less than the agreed power generation; the distributed power generation bears the power supply guarantee fee for the portion of the power generation that fails to fulfill the agreement, and the distributed power generation bears the power supply guarantee fee for the power generation corresponding to the power generation at the time point of power imbalance in the agreed power generation, both of which are calculated using formulas (1) and (2).

[0048] Preferably, in step S1, K g and k g The method to determine is: K g =0%, k g is 0; when 0%< K g When ≤5%, k g is 0.02; when 5%< K g When ≤10%, k g is 0.03; when 10%< K g When ≤15%, k g is 0.04; when 15%< K g When ≤20%, k g is 0.05; when 20%< K g When ≤25%, k g is 0.06; when 25%< K g When ≤30%, k g is 0.07; when 30%< K g When ≤35%, k g is 0.08; when 35%< K g When ≤40%, k g is 0.09.

[0049] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a method for designing a transmission fee that takes into account a high proportion of distributed power access. Based on the transmission and distribution price of the third regulatory period, the theoretical transmission and distribution price is calculated using forward price deduction. The results show that the theoretical transmission and distribution price of industrial and commercial users of each voltage level is lower than the transmission and distribution price implemented in the first two regulatory periods. Compared with the calculation of the transmission and distribution price in the first two regulatory periods, the third regulatory period is more perfect in the determination of the transmission and distribution price, and the original transmission and distribution price is refined, which is conducive to further reducing cross-subsidies and ultimately achieving fair determination of the transmission and distribution price. At the same time, according to the transmission fee mechanism proposed by the present invention, the recovery of grid costs can be guaranteed, and distributed power sources and power users will bear the responsibility for power stability fairly, which is conducive to promoting distributed power generation and improving the level of safe and stable operation. At the same time, it can improve the electricity consumption behavior of power users and increase their enthusiasm for participating in the consumption of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is the distributed power output curve and system load curve of Example 1.

[0051] Figure 2 This is the distributed power output curve and system load curve of Example 2.

[0052] Figure 3 This is the distributed power output curve and system load curve of Example 3.

[0053] Figure 4 This is the distributed power output curve and system load curve of Example 4. DETAILED DESCRIPTION

[0054] The present invention will be further described below with reference to specific embodiments.

[0055] A method for designing a transmission fee taking into account a high proportion of distributed power generation access includes the following steps:

[0056] S1: Set the power supply guarantee coefficient and specify the fee collection in different scenarios; the details are as follows:

[0057] For distributed power generation participating in distributed transactions, the grid can recover its investment costs by charging a grid access fee plus a power supply guarantee fee. The grid access fee refers to the theoretical transmission and distribution price of the provincial grid public network corresponding to the voltage level of the power user's access (excluding policy-based cross-subsidies), minus the theoretical transmission and distribution price of the highest voltage level involved in the distributed generation market transaction (excluding policy-based cross-subsidies).

[0058] Since there are deviations between the output forecast and load forecast of distributed power generation, this poses a challenge to the power supply guarantee of the power grid. The present invention calculates the power supply reliability by calculating the difference between the declared power generation of new energy and the actual power generation, divided by the declared power generation of new energy. The impact of the unstable output of distributed power generation on the power grid is compensated by increasing the power supply guarantee fee for distributed power generation. According to the real-time power supply reliability of distributed power generation, the power supply guarantee fee is obtained by multiplying the power difference by the cost coefficient under different power supply guarantee reliability. The formula is as follows:

[0059] (1)

[0060] (2)

[0061] Where K g For power supply reliability, Q d Reporting electricity consumption for new energy, Q g is the actual power generation of new energy, F g is the power supply guarantee fee, k g K is the power supply reliability cost coefficient. g With k g The determination method is shown in Table 1.

[0062] Table 1 Power supply guarantee coefficient

[0063]

[0064] S2: Obtain shared network data and calculate the theoretical transmission and distribution price based on the forward price method to derive the transmission fee. First, according to the provisions of the "Provincial Power Grid Transmission and Distribution Price Pricing Method", the grid company's permitted income is the transmission and distribution network cost borne by power users. The provincial power grid public network transmission and distribution price cost calculation method is as follows:

[0065] S2-1: Calculate the shared network licensing revenue, which consists of licensing costs, licensing benefits, and taxes. The formula is as follows:

[0066] (3)

[0067] (4)

[0068] (5)

[0069] Where, Allowing income for shared networks, To allow costs, To allow income, For taxes; represents the base period allowable cost of the transmission and distribution network, represents the permitted cost of additions or subtractions to the transmission and distribution network; It represents the effective assets of the transmission and distribution network that can accrue income. represents the permitted rate of return;

[0070] S2-2: Calculate the transmission and distribution costs for each voltage level. Allowable costs are aggregated based on the amount of electricity transmitted and allocated to each voltage level. Allowable income and taxes are aggregated based on the net value of fixed assets and allocated to each voltage level. The formula is as follows:

[0071] (6)

[0072] (7)

[0073] (8)

[0074] Where, for Voltage level transmission and distribution costs, for The proportion of electricity delivered by voltage level, for Percentage of fixed assets by voltage level; for Voltage level total transmission power, for Total amount of power transmitted by voltage level; for Net value of fixed assets at voltage level, for Net value of fixed assets at voltage level;

[0075] S2-3: Calculate the permitted revenue of transmission and distribution prices at each voltage level, where the total permitted revenue of a voltage level is composed of the permitted revenue of the current voltage level and the permitted revenue transmitted from the previous voltage level;

[0076] Electricity users at different voltage levels also have varying degrees of occupancy of the transmission and distribution network. Since power flows are transferred from the high-voltage transmission and distribution network to the low-voltage transmission and distribution network, electricity users connected to the high-voltage transmission and distribution network do not use the low-voltage transmission and distribution network. However, when high-voltage electricity users transmit electricity, in addition to supplying electricity users at their own voltage level, some electricity is also transmitted to low-voltage electricity users after being stepped down by transformers. Therefore, electricity users on the low-voltage transmission and distribution network not only use the transmission and distribution network at their own voltage level, but also occupy the high-voltage transmission and distribution network.

[0077] Considering the rationality of allocating transmission and distribution network costs, electricity users at lower voltage levels should, while bearing the transmission and distribution costs of their own voltage level, also share a portion of the costs of the higher-voltage transmission and distribution network that delivers electricity to that voltage level. Therefore, when calculating the permissible revenue for transmission and distribution prices at each voltage level, it is necessary to consider the power flow transmission relationship between different voltage levels.

[0078] Based on the power flow transmission relationship between transmission and distribution networks of different voltage levels, the cost transmission relationship between power grids of different voltage levels is determined as follows: 66 kV power users share the transmission and distribution network costs of 220 kV power users; 20 kV power users share the transmission and distribution network costs of 220 kV and 66 kV power users; 10 kV power users share the transmission and distribution network costs of 220 kV, 66 kV, and 20 kV power users; 1 kV and below power users only share the transmission and distribution network costs of 10 kV power users. The formula is:

[0079] (9)

[0080] Where, for Permitted income from voltage level transmission and distribution prices, for Voltage level transmission and distribution costs, for Voltage level transmission and distribution costs, for The amount of electricity delivered by the voltage level to users of this voltage level, for Voltage level Voltage level The amount of electricity delivered by the user, for Total amount of power transmitted by voltage level;

[0081] S2-4: Calculate the transmission and distribution price for industrial and commercial users at each voltage level using the following formula:

[0082] (10)

[0083] Where, for The transmission and distribution price for industrial and commercial users with a single voltage level system is for Voltage level single system industrial and commercial users share The proportion of permitted income from power transmission and distribution at each voltage level, for Electricity consumption of industrial and commercial users with a single voltage level system;

[0084] At the same voltage level, the peak load responsibility method and the maximum load method are usually used to allocate the transmission and distribution permitted revenue to different types of power users. However, both methods will lead to a lack of fairness in the allocation results of the transmission and distribution permitted revenue. Therefore, considering the dynamic changes in the load of different types of power users in different time periods, the comprehensive load method is used to calculate the permitted revenue allocation ratio for industrial and commercial users. :

[0085] (11)

[0086] Where, 、 、 and Represents residential users, agricultural users, single-system industrial and commercial users, and two-system industrial and commercial users in The annual maximum electricity load at the time, express Voltage level electricity users The ratio of the annual maximum electricity load at a certain time to the sum of the annual maximum electricity loads of power users of this voltage level at all times;

[0087] S2-5: Calculate the two-part transmission and distribution price for industrial and commercial users at each voltage level;

[0088] (12)

[0089] (13)

[0090] (14)

[0091] (15)

[0092] Where, 、 、 They are The electricity transmission and distribution price for industrial and commercial users with two-part voltage level system, including electricity quantity, capacity and demand, 、 、 The proportion of electricity consumption, capacity and demand transmission and distribution charges of industrial and commercial users in the total transmission and distribution charges is respectively for Voltage level two-part system shared by industrial and commercial users The proportion of permitted income from power transmission and distribution at each voltage level, for The electricity consumption of industrial and commercial users with two voltage levels is for Transformer capacity for industrial and commercial users with two voltage levels, for The annual maximum electricity load of industrial and commercial users with two voltage levels.

[0093] S3: Compare the power generation of distributed power generation with the agreed power generation to determine the fees to be borne by the user; calculate the power supply reliability of distributed power generation based on the power balance degree at each time point, obtain the power supply guarantee fee paid by distributed power generation, and determine the fees to be borne by distributed power generation, as follows:

[0094] Based on the principle that the grid access fee is borne by the user and the power supply guarantee fee is borne by the distributed power generation, the scenarios for the fees paid by users and distributed power generation are divided into four situations:

[0095] Ⅰ. The power generation of distributed generation is equal to the agreed power, and the power is balanced at each time point: the user pays the full amount of power purchase transmission fee;

[0096] II. The power generation of distributed generation is equal to the agreed power, and there is a power imbalance at a certain point in time: the user pays the full amount of power purchase transmission fee; the distributed generation bears the power supply guarantee fee corresponding to the power imbalance point in time, which is calculated using formulas (1) and (2);

[0097] III. The power generation of distributed generation is less than the agreed power, and the power is balanced at each time point: the user pays the transmission fee for the actual transaction between the user and the distributed generation; the user pays the corresponding voltage level transmission and distribution price for the part of the power purchased from the grid that is less than the agreed power; the distributed generation bears the power supply guarantee fee for the power that fails to fulfill the agreement, which is calculated using formulas (1) and (2);

[0098] IV. The power generation of distributed power generation is less than the agreed power generation, and the power is unbalanced at each time point: the user pays the transmission fee for the portion of the power actually traded between the user and the distributed power generation; the user pays the corresponding voltage level transmission and distribution price for the portion of the power purchased from the grid that is less than the agreed power generation; the distributed power generation bears the power supply guarantee fee for the portion of the power generation that fails to fulfill the agreement, and the distributed power generation bears the power supply guarantee fee for the power generation corresponding to the power generation at the time point of power imbalance in the agreed power generation, both of which are calculated using formulas (1) and (2).

[0099] The following example selects Province S as the research object and collects financial and electricity data from the province's power companies in 2022 through field research. The above method is used to design network fees, where the permitted costs, permitted revenues, and price-inclusive taxes for the transmission and distribution network at each voltage level are shown in Table 2, the power consumption of each type of user at each voltage level is shown in Table 3, and the current conduction relationship can be determined from the proportion of power supply to the current level and the lower level at each voltage level, as shown in Table 4. Based on the permitted costs, permitted revenues, and price-inclusive taxes for transmission and distribution at each voltage level in Province S, and considering the cost conduction relationship between different voltage levels, the transmission and distribution network costs for each voltage level in the province are calculated. Furthermore, the proportion of transmission and distribution network costs shared by different types of users at each voltage level is calculated, resulting in the permitted revenue for the transmission and distribution price at each voltage level, as shown in Table 5.

[0100] Table 2 Permitted costs, permissible revenues, and taxes included in the price of transmission and distribution networks at various voltage levels (100 million yuan)

[0101]

[0102] Table 3 Electricity consumption of industrial and commercial users at each voltage level (100 million kWh)

[0103]

[0104] Table 4 The proportion of power supply to the same level and the lower level at each voltage level

[0105]

[0106] Table 5 Permitted revenue from power transmission and distribution for users at each voltage level (100 million yuan)

[0107]

[0108] Table 5 shows that the permitted transmission and distribution revenues for users at different voltage levels vary significantly before and after accounting for the current conduction relationships between transmission and distribution networks at different voltage levels. Only 20% of the power load transmitted by the 220kV transmission and distribution network is supplied to users at this voltage level; the remaining load is transmitted to users at the 110kV, 35kV, and 10kV levels. After accounting for this current conduction relationship, the permitted transmission and distribution revenues borne by users at the 220kV voltage level are significantly reduced. Meanwhile, users at lower voltage levels, while sharing the permitted transmission and distribution revenues for their own voltage level, also have to share a portion of the permitted revenues for the next higher voltage level. Therefore, the permitted transmission and distribution revenues borne by users at lower voltage levels are significantly higher than those borne by users at higher voltage levels. For example, users at voltage levels below 1kV share 8.69 times the permitted transmission and distribution revenues borne by users at the 220kV voltage level.

[0109] Based on the annual load data of different power users at different voltage levels in Province S, we can obtain the transmission and distribution revenue allocation ratios for different users at different voltage levels, as shown in Table 6. Further calculations yield the single-part transmission and distribution price and the two-part transmission and distribution price for industrial and commercial users at each voltage level, as shown in Table 7.

[0110] Table 6 Apportionment ratio of transmission and distribution revenue allowed to different users at different voltage levels

[0111]

[0112] Table 7 Theoretical transmission and distribution prices for various voltage levels and types of users (yuan / kWh, yuan / kilowatt-month)

[0113]

[0114] Electricity users are connected to the grid at a voltage level of 10 kV, and distributed power generation projects are connected to the high-voltage side 35 kV (transmission and distribution price 0.0998 yuan / kWh, transmission and distribution price difference 0.0071 yuan / kWh) of the substation where the 10 kV line is located.

[0115] The following embodiments are various scenarios.

[0116] Example 1: The power generation of distributed generation is equal to the agreed power, which is the declared transaction power. , the user's power consumption is equal to the agreed power consumption, and the power is balanced at each time point. The user pays the full amount of power purchase and transmission fee. The distributed power output curve and system load curve of Example 1 are as follows Figure 1 As shown, the transmission and distribution fees charged for distributed power sources and users under Example 1 are shown in Table 8:

[0117] Table 8 Fee collection for Example 1

[0118]

[0119] Example 2: The power generation of distributed power generation is equal to the agreed power. , the user's electricity consumption is greater than the agreed electricity consumption. The user pays the grid fee for the actual electricity consumption traded between the user and the distributed power source; the user pays the corresponding voltage level transmission and distribution price for the portion of electricity purchased from the grid that exceeds the agreed electricity consumption. Example 2 Distributed power output curve and system load curve are as follows Figure 2 As shown, the transmission and distribution fees for distributed power sources and users under Example 2 are shown in Table 9:

[0120] Table 9 Fee collection for Example 2

[0121]

[0122] like Figure 2 As shown, from 9:00 to 14:00 and from 23:00 to 24:00, the user's electricity consumption is greater than the agreed electricity consumption. The large power grid needs to purchase electricity from the superior power grid (35kV) to ensure power balance, and the user needs to pay the transmission and distribution price corresponding to the voltage level of this electricity consumption.

[0123] Example 3: The power generation of the distributed power generation is less than the agreed power. , the user's electricity consumption is equal to the agreed electricity consumption. The user pays the grid fee for the actual electricity consumption traded between the user and the distributed power source; the power supply guarantee fee is paid for the part where the distributed power generation output is less than the declared output, and the corresponding voltage level transmission and distribution price is paid for the part where the power consumption is less than the agreed electricity consumption purchased from the grid. Example 2 Distributed power output curve and system load curve are as follows Figure 3 shown.

[0124] like Figure 3 As shown, from 1:00 to 4:00 and from 18:00 to 21:00, the output of the distributed power generation is less than the declared output. The large power grid needs to purchase electricity from the upper power grid (35kV) to ensure power balance. The distributed power generation must pay the voltage level transmission and distribution price and power supply guarantee fee corresponding to this amount of electricity. The power supply reliability coefficient and power supply guarantee fee at each time point are shown in Table 10. The transmission and distribution fee collection for distributed power generation and users under Example 3 is shown in Table 11:

[0125] Table 10 Power supply reliability coefficient and power supply guarantee cost at each time point

[0126]

[0127] Table 11 Fee collection for Example 3

[0128]

[0129] Example 4: The power generation of the distributed power generation is less than the agreed power. , the user's electricity consumption is greater than the agreed electricity consumption. The user pays the grid fee for the portion of electricity actually traded between the user and the distributed power source; the portion of electricity purchased from the grid that is greater than the agreed electricity consumption is paid the corresponding voltage level transmission and distribution price. The distributed power generation output is less than the declared output, and the user pays the power supply guarantee fee; the portion of electricity purchased from the grid that is less than the agreed electricity consumption is paid the corresponding voltage level transmission and distribution price. Example 4 Distributed power output curve and system load curve are as follows Figure 4 shown.

[0130] like Figure 4As shown, between 10:00 and 1:00 PM, the output of the distributed generation is less than the declared output, and the user's power consumption exceeds the agreed power. The large power grid needs to purchase power from the upper-level power grid (35kV) to ensure power balance. The distributed generation must pay the transmission and distribution price corresponding to the voltage level less than the declared power output and the power supply guarantee fee, while the user must pay the transmission and distribution price corresponding to the voltage level greater than the declared power output. The power supply reliability coefficient of the distributed generation and the power supply guarantee fee at each time point are shown in Table 12.

[0131] Table 12 Power supply reliability coefficient and power supply guarantee cost at each time point

[0132]

[0133] According to Table 12, the transmission and distribution fees charged to the distributed power source and the user under Example 4 are calculated as shown in Table 13:

[0134] Table 13 Example 4 Fee Collection

[0135]

[0136] The comparison of user and distributed power costs under various embodiments is shown in Table 14:

[0137] Table 14 Comparison of costs of various embodiments

[0138]

[0139] It can be seen from the above embodiments that when there is no deviation between the power generation of distributed power sources and the actual power consumption of users and the declared trading power, the user shall bear the transmission fee according to the trading power, and the distributed power source shall not bear any fees; when there is no deviation between the power generation of distributed power sources and the declared trading power, and the actual power consumption of users exceeds the declared power, the user shall bear the transmission and distribution price of the voltage level corresponding to the deviation power, and the distributed power source shall not bear any fees; when there is no deviation between the actual power consumption of users and the declared trading power, and the power generation of distributed power sources is lower than the declared power, the user shall bear the transmission fee according to the trading power, the distributed power source shall pay the power supply guarantee fee for the deviation power, and at the same time bear the transmission and distribution price of the voltage level corresponding to the deviation power.

[0140] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various variations and modifications. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for designing a transmission fee taking into account a high proportion of distributed power generation access, characterized by: The steps include: S1: Set the power supply guarantee coefficient and specify the fee collection in different scenarios; the details are as follows: The power supply reliability is calculated by calculating the difference between the declared power generation of renewable energy and the actual power generation, divided by the declared power generation of renewable energy. The impact of the unstable output of distributed power generation on the power grid is compensated by increasing the power supply guarantee fee for distributed power generation. Based on the real-time power supply reliability of distributed power generation, the power supply guarantee fee is calculated by multiplying the power difference by the cost coefficient under different power supply guarantee reliability. The formula is as follows: F g =(Q d -Q g )·k g (2) Where K g For power supply reliability, Q d Reporting electricity consumption for new energy, Q g is the actual power generation of new energy, F g is the power supply guarantee fee, k g Cost factor for ensuring reliability of power supply; S2: Obtain the shared network data, calculate the theoretical transmission and distribution price based on the forward price method, and derive the transmission fee; the details are as follows: According to the permitted income of the power grid enterprise, which is the transmission and distribution network cost borne by the power users, the cost calculation method of the provincial power grid public network transmission and distribution price is as follows: S2-1: Calculate the shared network licensing revenue, which consists of licensing costs, licensing benefits, and taxes. The formula is as follows: C z =C c +C e +E (3) C e =A·k A (5) Where C z For shared network permission income, C c is the allowable cost, C e is the allowed income, E is the tax; represents the base period allowable cost of the transmission and distribution network, represents the permitted cost of the transmission and distribution network; A represents the effective asset of the transmission and distribution network that can be used to accrue income, k A represents the permitted rate of return; S2-2: Calculate the transmission and distribution costs for each voltage level. Allowable costs are aggregated based on the amount of electricity transmitted and allocated to each voltage level. Allowable income and taxes are aggregated based on the net value of fixed assets and allocated to each voltage level. The formula is as follows: Where, F m is the transmission and distribution cost of voltage level m, is the proportion of electricity delivered at voltage level m, is the proportion of fixed assets at voltage level m; Q m is the total transmission power of voltage level m, Q i is the total transmission power of voltage level i; A m is the net value of fixed assets at voltage level m, A i is the net value of fixed assets at voltage level i; S2-3: Calculate the permitted revenue of transmission and distribution prices at each voltage level, where the total permitted revenue of a voltage level is composed of the permitted revenue of the current voltage level and the permitted revenue transmitted from the previous voltage level; According to the power flow transmission relationship between transmission and distribution networks of different voltage levels, the cost transmission relationship between power grids of different voltage levels is determined as follows: 66kV power users share the transmission and distribution network costs of 220kV power users; 20kV power users share the transmission and distribution network costs of 220kV and 66kV power users; 10kV power users share the transmission and distribution network costs of 220kV, 66kV, and 20kV power users; 1kV and below power users only share the transmission and distribution network costs of 10kV power users. The formula is: Where C m is the permitted income from transmission and distribution price for voltage level m, F l is the transmission and distribution cost of voltage level l, F m is the transmission and distribution cost of voltage level m, q m is the amount of electricity delivered from voltage level m to users at this voltage level, q lm Q is the amount of electricity delivered from voltage level l to voltage level m users, l is the total transmission power of voltage level 1; S2-4: Calculate the transmission and distribution price for industrial and commercial users at each voltage level using the following formula: Where, is the transmission and distribution price for industrial and commercial users with a single voltage level of m, The proportion of the permitted revenue from transmission and distribution of voltage level m allocated to industrial and commercial users of voltage level m, The electricity consumption of industrial and commercial users with a single voltage level of m; Taking into account the dynamic changes in load of different types of electricity users in different time periods, the comprehensive load method is used to calculate the allowable income sharing ratio of industrial and commercial users. Where, and are the annual maximum electricity loads of residential users, agricultural users, single-system industrial and commercial users, and two-system industrial and commercial users at time i, ξ m,i It represents the ratio of the annual maximum electricity load of the power users of voltage level m at time i to the sum of the annual maximum electricity loads of the power users of voltage level m at all times; S2-5: Calculate the two-part transmission and distribution price for industrial and commercial users at each voltage level; Where, They are the electricity, capacity and demand transmission and distribution prices for industrial and commercial users of two-part system with m voltage level, The proportion of electricity consumption, capacity and demand transmission and distribution charges of industrial and commercial users in the total transmission and distribution charges is respectively The proportion of the permitted revenue from transmission and distribution of voltage level m shared by industrial and commercial users of the two-part system of voltage level m, The electricity consumption of industrial and commercial users with two-part system at voltage level m is: The transformer capacity of two-part industrial and commercial users of voltage level m is: The annual maximum electricity load of two-part industrial and commercial users at voltage level m; S3: Compare the power generation of distributed power generation with the agreed power generation to determine the fees to be borne by the user; calculate the power supply reliability of distributed power generation based on the power balance degree at each time point, obtain the power supply guarantee fee paid by distributed power generation, and determine the fees to be borne by distributed power generation; the details are as follows: Based on the principle that the grid access fee is borne by the user and the power supply guarantee fee is borne by the distributed power generation, the scenarios for the fees paid by users and distributed power generation are divided into four situations: Ⅰ. The power generation of distributed generation is equal to the agreed power, and the power is balanced at each time point: the user pays the full amount of power purchase transmission fee; II. The distributed generation capacity is equal to the agreed capacity, and there is a power imbalance at a certain point in time: the user pays the full amount of the purchased electricity transmission fee; The distributed generation bears the power supply guarantee cost corresponding to the power imbalance point, which is calculated using formulas (1) and (2); III. If the power generation of the distributed generation is less than the agreed power, and the power is balanced at all times: the user pays the transmission fee for the actual power transaction between the user and the distributed generation; for the power purchased from the grid that is less than the agreed power, the user pays the transmission and distribution price for the corresponding voltage level; The distributed generation shall bear the power supply guarantee costs for the electricity volume that fails to fulfill the agreement, which shall be calculated using formulas (1) and (2); IV. If the power generation of the distributed generation is less than the agreed amount and there is an imbalance in power at different points in time: the user pays the transmission fee for the actual amount of power traded between the user and the distributed generation; and pays the transmission and distribution price for the corresponding voltage level for the amount of power purchased from the grid that is less than the agreed amount. The distributed generation shall bear the power supply guarantee costs for the electricity quantity that is not fulfilled in the agreement, and the distributed generation shall bear the power supply guarantee costs for the electricity quantity corresponding to the power imbalance point in the agreed electricity quantity, both of which are calculated using formulas (1) and (2).

2. The method for designing a transmission fee taking into account a high proportion of distributed power generation access according to claim 1, characterized in that: In step S1, K g is power supply reliability; k g K is the power supply reliability cost coefficient, g With k g The method of determining is: when K g =0%, k g is 0; when 0% <K g When ≤5%, k g is 0.02; when 5% <K g When ≤10%, k g is 0.03; when 10% <K g When ≤15%, k g is 0.04; when 15% <K g When ≤20%, k g is 0.05; when 20% <K g When ≤25%, k g is 0.06; when 25% <K g When ≤30%, k g is 0.07; when 30% <K g When ≤35%, k g is 0.08; when 35% <K g When ≤40%, k g is 0.09.

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