CN115967120B - 220 KV power grid on-line transformer substation judging method and capacity-to-load ratio calculating method - Google Patents

Abstract

The invention discloses a 220 KV power grid on-line substation judging method, which comprises the steps of obtaining substation data information of a 220 KV regional power grid; calculating the ratio of the power on the network to the power off the network of the transformer substation, and the probability of new energy or conventional power supply power; and judging the online substation according to the data information and the selected maximum load time period. The invention also discloses a capacity-to-load ratio calculation method comprising the 220 KV power grid on-line substation judgment method. According to the invention, different factors are comprehensively considered so as to judge whether the transformer substation belongs to an internet-surfing transformer substation or not; therefore, the invention has high reliability, good accuracy and higher efficiency; meanwhile, the invention can provide accurate data reference for the calculation process of the capacity-to-load ratio, so that the calculation process of the capacity-to-load ratio is more accurate and reliable.

Description

220 kV grid-connected substation determination method and capacity load ratio calculation method

Technical Field

The present invention belongs to the technical field of electrical automation, and in particular relates to a method for determining a 220 kV grid-connected substation and a method for calculating a capacity-load ratio.

Background Art

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.

At present, with the rapid development of new energy power generation systems, new energy power generation systems have begun to be integrated into 110 kV and below voltage level power grids on a large scale. In new energy-rich areas, large-scale grid connection of new energy will lead to the transmission of new energy to the upper grid through the main transformer of the 220 kV substation. At this time, the substation mainly undertakes the task of transmitting new energy electricity, rather than the load supply function. Therefore, when analyzing the regional load supply capacity, it is necessary to calculate the 220 kV regional power grid offline capacity-load ratio, that is, it is necessary to reasonably determine the 220 kV substation capacity of the region at the time of calculation. Therefore, how to accurately eliminate the substations that mainly undertake the task of transmitting electricity in the 220 kV substation, that is, to determine the 220 kV grid-connected substations, is of great significance for accurately calculating the 220 kV offline capacity-load ratio in the region.

However, in the current calculation process of the offline capacity-load ratio of the 220 kV regional power grid, the above-mentioned special situation is not taken into account, that is, the substations that are mainly responsible for the task of sending power in the 220 kV substations are excluded, or the 220 kV grid-connected substations are not judged. Therefore, the existing technology does not judge the 220 kV grid-connected substations; this makes the existing capacity-load ratio calculation scheme lead to the calculated offline capacity-load ratio being too large or too small, and cannot truly and accurately reflect the problems existing in the power supply of the grid.

Summary of the invention

One of the purposes of the present invention is to provide a method for determining a 220 kV grid-connected substation with high reliability, good accuracy and high efficiency.

A second object of the present invention is to provide a method for calculating the capacity-load ratio that includes the method for determining a 220 kV grid-connected substation.

The 220 kV power grid on-grid substation determination method provided by the present invention comprises the following steps:

S1. Obtain substation data information of 220 kV regional power grid;

S2. According to the data information obtained in step S1, the ratio of the on-grid power of the substation to the off-grid power and the probability of sending new energy or conventional power are calculated;

S3. According to the data information calculated in step S2 and the selected maximum load period, the grid-connected substation is determined.

Step S2, according to the data information obtained in step S1, calculates the ratio of the on-grid power to the off-grid power of the substation and the probability of sending up new energy or conventional power, which specifically includes the following steps:

Based on the 8760 operating hours data of the current substation last year, the annual online power consumption of the current substation last year is counted P _i ≤ 0 and off-grid power P _i > 0, where W _up is the amount of electricity online, ΔT is the length of the time period, P _i is the power of the substation at the i-th hour, and P _i ≤ 0 means that the substation is sending electricity, and P _i > 0 means that the substation is supplying load normally;

The ratio of the current on-grid power to the off-grid power of the substation is calculated as

Calculate the probability p of the current substation sending new energy or conventional power supply power as follows: P _i ≤ 0 and i∈(1,35040), where N _up,year is the number of loads less than 0 in the current substation operation data throughout the year, and N _year is the total number of current substation operation data points throughout the year.

Step S3, according to the data information calculated in step S2 and the selected maximum load period, determines the grid-connected substation, specifically including the following steps:

According to the ratio η of the grid-connected power to the grid-connected power of the substation obtained in step S2 and the probability p of the substation transmitting renewable energy or conventional power, the grid-connected substation is determined;

Select the maximum load period, calculate the net grid-connected power of the current substation during the maximum load period, the probability of the substation sending power during the maximum load period, and the ratio of the maximum up-sending power to the maximum down-sending power during the maximum load period, so as to determine the grid-connected substation;

When the installed capacity of the power source connected to the current substation is greater than or equal to the current maximum load of the substation, the grid-connected substation is judged based on the relationship between the load and the maximum load of the substation and the relationship between the regional load and the regional maximum load during the maximum load period.

The determination of the grid-connected substation based on the ratio η of the grid-connected power to the grid-connected power obtained in step S2 and the probability p of the substation transmitting renewable energy or conventional power is specifically performed including the following steps:

The following rules are used for judgment:

If η≥1 and p＞0.5, it means that the current substation’s annual online power generation is greater than the offline power generation, and the annual online operation probability is greater than the offline operation probability, then the current substation is determined to be an online substation;

If η<1 or η>1, and p<0.5, the current substation is determined to be a grid-connected substation.

The selected maximum load period, calculating the net grid-connected power of the current substation during the maximum load period, the probability of the substation sending power during the maximum load period, and the ratio of the maximum sending power to the maximum sending power during the maximum load period, so as to determine the grid-connected substation, specifically includes the following steps:

Select the maximum load and take the maximum as the dividing point, take X days before and after, and a total of 2X days as the maximum load segment; X is a set real number;

Calculate the net on-grid power of the current substation during the maximum load period W _N,up Where _Pi is the power of the substation at the i-th hour;

The probability p of the substation transmitting power during the maximum load period is calculated as P _i ≤0; N _up is the number of data points less than 0, which indicates that the substation is transmitting power; N is the number of data points collected by the substation during the maximum load period;

The ratio α of the maximum uplink power to the maximum downlink power during the maximum load period is calculated as Where P _i,up,max is the maximum up-transmission power of the substation during the maximum load period; P _i,down,max is the maximum down-transmission power of the substation during the maximum load period;

The following rules are used for judgment:

If p＞0.5 and W _N,up ＜0, the current substation is determined to be an on-grid substation;

If p＞0.5 and α＞1, the current substation is determined to be an on-grid substation.

When the installed capacity of the power source connected to the current substation is greater than or equal to the maximum load of the current substation, the on-grid substation is determined according to the relationship between the load and the maximum load of the substation and the relationship between the regional load and the regional maximum load during the maximum load period, specifically including the following steps:

Based on the historical operation data, obtain the moment when the current regional load P _load,j is greater than Y% of the regional maximum load P _load,max during the maximum load period, P _load,j ≥0.85P _load,max ,j∈(1,N ₁ ); then, obtain the load P _j of the current substation at the corresponding j-th moment, and obtain the relationship between the load P _j and 10% of the maximum load of the substation, P _j ≤0 or P _j ≤0.1P _{load,station,max} ,j∈(1,N ₂ ); where P _{load,station,max} is the maximum load that the current substation can carry; N ₁ is the number of data at which the current regional load P _load,j is greater than Y% of the regional maximum load P _load,max during the maximum load period; N ₂ is the number of data satisfying P _j ≤0 or P _j ≤0.1P _{load,station,max} ;

Calculate the probability p as P _j ≤0 or P _j ≤0.1P _{load,station,max} ;

The following rules are used for judgment:

If p＞0.5, the current substation is determined to be an on-grid substation.

The present invention also provides a method for calculating the capacity-load ratio including the method for determining a 220 kV grid-connected substation, which specifically includes the following steps:

A. Using the above-mentioned 220 kV grid-connected substation determination method, the grid-connected substations in the area are scheduled;

B. When calculating the regional 220 kV grid capacity-load ratio, exclude the capacity of the grid-connected substation obtained in step A;

C. Based on the data information obtained in step B, calculate the off-grid capacity load ratio of the 220 kV regional power grid.

When calculating the regional 220 kV grid-connected capacity-load ratio in step B, the capacity of the grid-connected substation obtained in step A is eliminated, which specifically includes the following steps:

Eliminate the capacity of the grid-connected substation obtained in step A;

When calculating the regional 220 kV grid capacity load ratio, substations that are mainly used by high-energy-consuming users are eliminated; the substations that are mainly used by high-energy-consuming users include substations that serve the iron and steelmaking industries and the electrolytic aluminum industry.

The 220 kV grid-connected substation determination method and load-to-capacity ratio calculation method provided by the present invention take into account the grid-connected power, grid-offline power, the ratio of grid-connected power to grid-offline power of the substation throughout the year, the probability of the substation sending new energy or conventional power, the situation and probability of the substation sending power during the maximum load period in the region, the power sending situation of the substation when the regional load is greater than 85% of the regional maximum load when the installed capacity of the power source connected to the substation is greater than or equal to the maximum load of the substation, and the load characteristic constraints of the substation dominated by high-energy-consuming users, etc., comprehensively consider different factors to determine whether the substation belongs to the grid-connected substation; therefore, the present invention has high reliability, good accuracy and high efficiency; at the same time, the present invention can provide accurate data reference for the load-to-capacity ratio calculation process, so that the load-to-capacity ratio calculation process is more accurate and reliable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a flow chart of a determination method of the present invention.

FIG. 2 is a schematic diagram of a method flow chart of a method for calculating a capacity-load ratio according to the present invention.

DETAILED DESCRIPTION

FIG1 is a schematic diagram of a method flow chart of the determination method of the present invention: The 220 kV grid-connected substation determination method provided by the present invention comprises the following steps:

S1. Obtain substation data information of 220 kV regional power grid;

S2. According to the data information obtained in step S1, the ratio of the on-grid power to the off-grid power of the substation and the probability of sending new energy or conventional power are calculated; specifically, the steps include:

Based on the 8760 operating hours data of the current substation last year, the annual online power consumption of the current substation last year is counted P _i ≤ 0 and off-grid power P _i > 0, where W _up is the amount of electricity online, ΔT is the length of the time period, P _i is the power of the substation at the i-th hour, and P _i ≤ 0 means that the substation is sending electricity, and P _i > 0 means that the substation is supplying load normally;

The ratio of the current on-grid power to the off-grid power of the substation is calculated as

Calculate the probability p of the current substation sending new energy or conventional power supply power as follows: P _i ≤ 0 and i∈(1,35040), where N _up,year is the number of loads less than 0 in the current substation operation data throughout the year, and N _year is the total number of current substation operation data points throughout the year;

S3. According to the data information calculated in step S2 and the selected maximum load period, the grid-connected substation is determined; specifically comprising the following steps:

According to the ratio η of the grid-connected power of the substation to the grid-connected power obtained in step S2 and the probability p of the substation transmitting renewable energy or conventional power, the grid-connected substation is determined; specifically, the following steps are included:

The following rules are used for judgment:

If η≥1 and p＞0.5, it means that the current substation’s annual online power generation is greater than the offline power generation, and the annual online operation probability is greater than the offline operation probability, then the current substation is determined to be an online substation;

If η<1 or η>1, and p<0.5, the current substation is determined to be an off-grid substation;

The maximum load period is selected, and the net grid-connected power of the current substation during the maximum load period, the probability of the substation sending power during the maximum load period, and the ratio of the maximum sending power to the maximum sending power during the maximum load period are calculated, so as to determine the grid-connected substation; specifically, the following steps are included:

Analyze the current situation and probability of the substation sending electricity during the period of regional maximum load. Usually, the daily maximum load period occurs between 6 pm and 11 pm. Affected by the regional climate and electricity consumption habits, the annual maximum load usually occurs in summer or winter. The annual maximum load occurs in different regions in different seasons. Summer is usually from July to August, and winter is usually from January to December of the following year. Since there must be a stable load growth process when the maximum load occurs, therefore, the maximum load is selected, and the maximum is used as the dividing point. X days (preferably 7 days) are taken before and after, and a total of 2X days (preferably 14 days) are taken as the maximum load period; X is a set real number;

Calculate the net on-grid power of the current substation during the maximum load period W _N,up Where _Pi is the power of the substation at the i-th hour;

The probability p of the substation transmitting power during the maximum load period is calculated as P _i ≤0; N _up is the number of data points less than 0, which indicates that the substation is transmitting power; N is the number of data points collected by the substation during the maximum load period;

The ratio α of the maximum uplink power to the maximum downlink power during the maximum load period is calculated as Where P _i,up,max is the maximum up-transmission power of the substation during the maximum load period; P _i,down,max is the maximum down-transmission power of the substation during the maximum load period;

The following rules are used for judgment:

If p＞0.5 and W _N,up ＜0, the current substation is determined to be an on-grid substation;

If p＞0.5 and α＞1, the current substation is determined to be an on-grid substation;

When the installed capacity of the power source connected to the current substation is greater than or equal to the current maximum load of the substation, the online substation is determined based on the relationship between the load and the maximum load of the substation and the relationship between the regional load during the maximum load period and the regional maximum load. The specific steps include:

Based on the historical operation data, obtain the moment when the current regional load P _load,j is greater than Y% (preferably 85%) of the regional maximum load P _load,max during the maximum load period, P _load,j ≥0.85P _load,max ,j∈(1,N ₁ ); then, obtain the load P _j of the current substation at the corresponding j-th moment, and obtain the relationship between the load P _j and 10% of the maximum load of the substation, P _j ≤0 or P _j ≤0.1P _{load,station,max} ,j∈(1,N ₂ ); wherein P _{load,station,max} is the maximum load that the current substation can carry; N ₁ is the number of data at which the current regional load P _load,j is greater than Y% of the regional maximum load P _load,max during the maximum load period; N ₂ is the number of data satisfying P _j ≤0 or P _j ≤0.1P _{load,station,max} ;

Calculate the probability p as P _j ≤0 or P _j ≤0.1P _{load,station,max} ;

The following rules are used for judgment:

If p＞0.5, the current substation is determined to be an on-grid substation.

The determination method of the present invention is described below in conjunction with an embodiment:

Take a prefecture-level city in a new energy-rich area in a provincial power grid as an example. The city has a total of 15 220 kV substations. As of the end of 2021, the main transformer capacity of the 220 kV substation in the region was 4.2 million kVA. The maximum load in the region in 2021 occurred in winter, with a regional maximum load of 2.2172 million kW and a 220 kV grid-connected maximum load of 1.3389 million kW. At this time, the loads of the 15 substations are all positive numbers, and these substations all transmit electricity to the lower-level power grid at the moment of maximum load. However, some of these substations have a small supply load, and they are in operation 365 days a year, and most of the time they are transmitting electricity to the upper-level power grid. If the 220 kV grid-connected substations are not excluded when analyzing the 220 kV grid-connected capacity-load ratio in the region, the calculated grid-connected capacity-load ratio is 3.14. This capacity-load ratio is too large and cannot accurately reflect the problems existing in the power grid, so it is necessary to reasonably eliminate the upstream network and then obtain the minimum capacity-load ratio of the 220 kV downstream network based on the substation capacity and downstream load.

Based on the above analysis, the operating data of 15 220 kV substations in the city in 2021 were analyzed to determine the number of online stations and the capacity of main transformers in the area.

The 15 substations are named Station 1, Station 2, Station 3, ..., Station 15. First, Station 1 is taken as an example for analysis:

Analyzing the full-year operation data of Station 1, we can see that:

W _up,station1 = -313887337 kWh

W _{down,station1} =251,504,780 kWh

According to the power transmission up and power transmission down, the ratio between the two can be calculated, that is:

According to the value of η and the probability of p(P _i ≤0), it can be determined that the on-grid power of Station 1 substation is greater than the off-grid power throughout the year;

The period of high load is 5 hours in total. The data points are collected at intervals of 15 minutes, and 21 data points can be obtained in one day. The day when the regional maximum load occurs is taken as the node. The actual operation data is analyzed for 7 days before and after, and a total of 315 sets of data are obtained, that is, N = 315. The maximum on-grid load of the substation is 193,780 kilowatts, and the maximum off-grid load is 83,580 kilowatts. It can be calculated as follows:

Therefore, according to the judgment basis, Station 1 substation is judged to be an on-grid substation;

At the end of 2021, the installed capacity of power connected to Station 1 substation was 450,000 kilowatts. The substation has two 180,000 kilowatt-ampere main transformers. The maximum load in 2021 was 95,000 kilowatts. Therefore, the installed capacity of new energy connected to the substation is greater than the maximum load of the substation.

At this time, 85% of the maximum load in the region is 1.8846 million kilowatts. Therefore, according to the analysis of actual operation data, there are 285 data points with a load greater than 1.8846 million kilowatts in the region throughout the year, that is, N ₁ = 285. From this, the load situation of the substation at the corresponding time can be obtained. Through analysis, it can be seen that there are 93 data points with a load less than 0 at the corresponding time, and 50 data points with a load less than 10% of the maximum load of the substation.

According to the judgment condition, that is, p(P _j ≤0or0.1P _{load,station,max} )＞0.5, the substation is considered to be an on-grid substation;

Since there are no high-energy-consuming users under this substation, if this is used as the only basis for judgment, there is no need to exclude the capacity of the 220 kV Station 1 substation when calculating the 220 kV grid load ratio in the area.

Based on the above analysis, it can be seen that when calculating the grid-connected capacity-load ratio in the area, the capacity of the 220 kV Station 1 substation needs to be excluded, that is, the substation is considered to be an online substation for transmitting electricity from renewable energy.

Then take Station 2 as an example for analysis:

Analyzing the full-year operation data of Station 2, we can see that:

W _up,station2 = -824,278,330 kWh

W _{down,station2} =557,684,800 kWh

According to the power transmission up and power transmission down, the ratio between the two can be calculated, that is:

According to the value of η and the probability of p(P _i ≤0), it can be determined that Station 2 is a grid-connected substation.

The period of high load is 5 hours in total. We take data points at intervals of 15 minutes, and get 21 data points in one day. The day when the regional maximum load occurs is taken as the node. We take 7 days before and after and analyze the actual operation data, and get a total of 315 sets of data, that is, N = 315. From this, we can calculate:

Therefore, according to the judgment basis, Station 2 substation is judged to be a grid-connected substation;

At the end of 2021, the installed capacity of power connected to the Station 2 substation was 230,000 kilowatts. The substation has a total of 180,000 kilowatt-ampere main transformer. The maximum load in 2021 was 97,000 kilowatts. Therefore, the installed capacity of power connected to the substation is greater than the maximum load of the substation.

At this time, 85% of the maximum load in the region is 1.8846 million kilowatts. Therefore, according to the analysis of actual operation data, there are 285 data points with a load greater than 1.8846 million kilowatts in the region throughout the year, that is, N ₁ = 285. From this, the load situation of the substation at the corresponding time can be obtained. Through analysis, it can be seen that there are 2 data points with a load less than 0 at the corresponding time, and 50 data points with a load less than 10% of the maximum load of the substation.

According to the judgment condition, the substation does not satisfy p(P _j ≤0or 0.1P _{load,station,max} )＞0.5, and the substation is considered to be an off-grid substation;

Since there are no high-energy-consuming users under this substation, if this is used as the only basis for judgment, there is no need to exclude the capacity of the 220 kV Station 2 substation when calculating the 220 kV grid load ratio in the area.

Based on the above analysis, it can be seen that when calculating the grid-connected capacity-load ratio in the area, the capacity of the 220 kV Station 2 substation needs to be excluded, that is, the substation is considered to be an online substation.

After analyzing the 15 220 kV substations in the city according to the above method, the network connection situation in the area can be obtained, as shown in the following table:

Table 1 Schematic diagram of 220 kV grid-connected substation in a certain city

Substation name Substation capacity (10,000 kVA) Is it an on-grid substation? Station1 36 yes Station 2 18 no Station3 36 yes Station4 18 no Station5 30 yes Station6 36 yes Station7 36 no Station8 twenty four no Station9 twenty four no Station10 twenty four no Station11 twenty four no Station12 36 no Station13 36 no Station14 18 yes Station15 twenty four no

As of the end of 2021, the 15 220 kV substations in the region have a total capacity of 4.2 million kVA, of which 10 220 kV substations are off-grid substations with a substation capacity of 2.64 million kVA; 5 220 kV substations are on-grid substations with a substation capacity of 1.56 million kVA. According to the above method, the minimum load-to-capacity ratio during the maximum load period in winter in the region is 1.77, which meets the requirements of relevant guidelines (the load-to-capacity ratio in the 220 kV area is controlled within the range of 1.7 to 2.0). At this time, the 220 kV off-grid load in the region is 1.1153 million kW, and the 220 kV off-grid substation capacity after excluding the on-grid capacity is 1.98 million kVA.

The grid-connected site obtained by the above method is consistent with the 220 kV grid-connected substation currently considered in actual operation, which verifies the effectiveness of the proposed method. At the same time, the results obtained can also accurately reflect the situation of the 220 kV power grid in the region to ensure load power supply.

FIG2 is a flow chart of the method for calculating the capacity-load ratio of the present invention: The method for calculating the capacity-load ratio provided by the present invention, which includes the method for determining the 220 kV grid-connected substation, specifically includes the following steps:

A. Using the above-mentioned 220 kV grid-connected substation determination method, the grid-connected substations in the area are scheduled;

B. When calculating the regional 220 kV grid-connected capacity-load ratio, the capacity of the grid-connected substation obtained in step A is eliminated; specifically, the following steps are included:

Eliminate the capacity of the grid-connected substation obtained in step A;

When calculating the regional 220 kV grid capacity load ratio, substations with high energy consumption users are excluded; the substations with high energy consumption users are defined as industries such as iron smelting and electrolytic aluminum industries;

The core of this step is that for some substations that are mainly high-energy-consuming users, the user's power load characteristics are mainly determined by the electricity price. The maximum load time of such users usually occurs after 12 o'clock in the evening. During the peak load period of the power grid, the load level of the substation is relatively low due to factors such as electricity prices. Therefore, when analyzing the offline capacity-load ratio, the capacity of such substations needs to be eliminated, but such substations do not belong to online substations.

C. Based on the data information obtained in step B, calculate the off-grid capacity load ratio of the 220 kV regional power grid.

Claims (3)

1. A220 KV power grid on-line transformer substation judging method comprises the following steps:

s1, acquiring substation data information of a 220 kilovolt regional power grid;

S2, calculating the ratio of the power on the network to the power off the network of the transformer substation according to the data information obtained in the step S1, and the probability of the occurrence of new energy or conventional power supply power; the method specifically comprises the following steps:

based on 8760 operation hours data of the current transformer substation in the last year, the annual internet power of the current transformer substation in the last year is counted P _i is less than or equal to 0 and the power of the power supply under the netP _i is more than 0, wherein W _up is the power on line, deltaT is the length of a time period, P _i is the power of the transformer substation in the ith hour, P _i is less than or equal to 0 and represents the power transmitted by the transformer substation, and P _i is more than 0 and represents the normal load supply of the transformer substation;

Calculating the ratio eta of the on-line electric quantity and the off-line electric quantity of the current transformer substation as

Calculating the probability p of new energy or conventional power supply power sent by the current transformer substation asP _i is less than or equal to 0 and i epsilon (1,35040), wherein N _up,year is the number of loads less than 0 in the current transformer substation operation data of the whole year, and N _year is the total number of the current transformer substation operation data points of the whole year;

S3, judging the online substation according to the data information obtained by calculation in the step S2 and the selected maximum load period; the method specifically comprises the following steps:

judging the online substation according to the ratio eta of the online electric quantity and the offline electric quantity of the substation and the probability p of new energy or conventional power supply power sent by the substation, which are obtained in the step S2; the method specifically comprises the following steps:

The following rules are adopted for judgment:

if eta is more than or equal to 1 and p is more than 0.5, the annual online electric quantity of the current transformer substation is larger than the offline electric quantity, the annual online operation probability is larger than the offline operation probability, and the current transformer substation is judged to be the online transformer substation;

if eta is less than 1 or eta is more than 1 and p is less than 0.5, judging that the current transformer substation is an off-grid transformer substation;

selecting a maximum load period, and calculating net surfing electric quantity of a current transformer substation in the maximum load period, probability of power transmission of the transformer substation in the maximum load period and ratio of maximum power transmission to maximum power transmission in the maximum load period, so as to judge the surfing transformer substation; the method specifically comprises the following steps:

selecting the maximum load, taking the maximum as a demarcation point, taking the time of X days before and after, and taking the total time of 2X days as a maximum load section; x is a set real number;

Calculating the net surfing electric quantity W _N,up of the current transformer substation in the maximum load period as Wherein P _i is the power of the transformer station at the ith hour;

calculating the probability p of power transmission of the transformer substation in the maximum load period as P _i is less than or equal to 0; n _up is the number when the data is smaller than 0, and represents the power sent by the transformer substation at the moment; n is the number of data points collected by the transformer substation in the maximum load period;

Calculating the ratio alpha of the maximum upward power to the maximum downward power in the maximum load period as Wherein P _i,up,max is the maximum upward power of the transformer substation in the maximum load period; p _i,down,max is the maximum downward power of the transformer substation in the maximum load period;

The following rules are adopted for judgment:

If p is more than 0.5 and W _N,up is less than 0, judging that the current transformer substation is an online transformer substation;

if p is more than 0.5 and alpha is more than 1, judging that the current transformer substation is an online transformer substation;

when the installed capacity of the power supply accessed by the current transformer substation is larger than or equal to the maximum load of the current transformer substation, judging the online transformer substation according to the relation between the load and the maximum load of the transformer substation and the relation between the regional load and the regional maximum load in the maximum load period; the method specifically comprises the following steps:

Acquiring a moment when the current regional load P _load,j is greater than Y% of the regional maximum load P _load,max in the maximum load period based on the historical operation data, P _load,j≥0.85P_load,max,j∈(1,N₁); then, obtaining the load P _j of the current transformer substation at the corresponding j-th moment, and obtaining the relation between the load P _j and 10% of the maximum load of the transformer substation, wherein P _j is less than or equal to 0 or P _j≤0.1P_{load,station,max},j∈(1,N₂); wherein P _{load,station,max} is the maximum load available for the current transformer substation; n ₁ is the number of data obtained at the moment when the current regional load P _load,j is greater than Y% of the regional maximum load P _load,max in the maximum load period; n ₂ is the number of data meeting the requirement that P _j is less than or equal to 0 or P _j≤0.1P_{load,station,max};

Calculating the probability p as P _j is less than or equal to 0 or P _j≤0.1P_{load,station,max};

The following rules are adopted for judgment:

if p is more than 0.5, the current transformer substation is judged to be the internet transformer substation.

2. A method for calculating a capacity ratio comprising the 220 kv power grid-on-line substation determination method of claim 1, comprising the steps of:

A. Scheduling the network substation in the area by adopting the 220 KV power grid network substation judging method;

B. C, eliminating the capacity of the network substation obtained in the step A when the network capacity-to-load ratio of 220 kilovolts in the area is calculated;

C. And C, calculating the lower network capacity-to-load ratio of the 220 KV regional power grid according to the data information obtained in the step B.

3. The method for calculating the capacity/load ratio according to claim 2, wherein in the step B, when calculating the network capacity/load ratio under 220 kv in the area, the capacity of the network substation obtained in the step a is removed, and the method specifically comprises the following steps:

Removing the capacity of the online substation obtained in the step A;

When the network capacity-load ratio is calculated under 220 kilovolts in the area, eliminating the transformer substation mainly with high-energy-consumption users; the transformer substation mainly comprises transformer substations mainly comprising iron-making industry and electrolytic aluminum industry.