Group electric heating load peak time shifting method suitable for relieving transformer area overload problem

Abstract

The invention discloses a group electric heating load peak time shifting method suitable for relieving the transformer area overload problem, and belongs to the technical field of temperature control loads. According to the method, the requirements of three residents such as resident comfort and the same electricity consumption and electricity cost are equivalent by operation constraints such as peak shifting-valley shifting, unchanged electric quantity before and after adjustment and peak shifting relay-adjustment duration limitation, and the transformer area over-capacity target is equivalently relieved by taking the minimum daily peak load as the target; based on data cleaning and a 01 integer linear programming method, rapid optimization solution is realized, an individual user name, a start-stop time period optimization scheme, group aggregation adjustment power and a peak load suppression effect picture which are expected to be adjusted are output, and statistics is performed on the number and the overload rate of a transformer area which still has overload after optimization regulation. And a theoretical support is provided for the accurate capacity expansion and the orderly capacity expansion of the transformer in the transformer area from urgent to slow.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature control loads, and in particular relates to a method for time shifting a group electric heating load peak suitable for alleviating the problem of overload in a distribution area. Background Art

[0002] As people's demand for safety and comfort increases, coal stove heating in rural areas is gradually replaced by electric heating. In pursuit of economical electricity use, electric heating equipment is often set to be put into operation around 8:00 and 21:00 when the peak electricity price is handed over. For example, it is put into operation during the valley electricity price period from 21:00 to 22:00 to enjoy the comfortable indoor temperature at the first time; it is put into operation from 07:00 to 08:00 to maximize the use of low electricity prices during the valley period to heat and store heat to maintain the comfortable indoor temperature for a long time, resulting in double peaks in daily load, which in turn leads to the problem of transformers in the substation area being easily damaged by overcapacity, which needs to be solved urgently.

[0003] Therefore, a new technical solution is urgently needed in the prior art to solve this problem. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for shifting the peak of group electric heating load suitable for alleviating the problem of overload in the substation, so as to solve the technical problem that the electric heating equipment is often put into operation around 8:00 and 21:00 when the peak electricity price is transferred, resulting in double peaks of daily load, which in turn makes the transformer in the substation easily damaged by overcapacity.

[0005] A method for shifting the peak load of group electric heating suitable for alleviating the overload problem of a transformer area comprises the following steps, and the following steps are performed in sequence:

[0006] Step 1: Collect relevant user information obtained by the data supervision platform within 24 hours in a 24-hour cycle, and perform the operations of the subsequent steps once in a cycle;

[0007] The data supervision platform is set to ensure that each area it supervises has only one transformer and one area meter for measuring the power of the transformer, each area has N users, and each user has only one electric heating device;

[0008] The user information includes the maximum capacity S of each transformer area tf , the power data P of each area meter at each sampling time tf 、Number of electric heating equipment in each area e2h 、Number of electric heating equipment in each area e2h , corresponding to the electric heating equipment name and the electric heating equipment number, the power data P of the electric heating load group at each sampling time e2h, where tf stands for transformer, and e2h is the abbreviation of electricity to heat;

[0009] Step 2: Set the heavy load power limit of the transformer in the substation area, obtain the assigned substation meter power at each sampling time and the residential user power at each sampling time;

[0010] Step 3: Obtain the power curve of each electric heating device through the collected historical operation data of each electric heating device, and judge the operation status of each electric heating device through the power curve; the operation status of the electric heating device is marked with 0 or 1, 0 means shutdown, and 1 means operation;

[0011] On the power curve, the operating power of the electric heating equipment in operation fluctuates around the same mean value, which is the capacity Pe of the electric heating equipment.

[0012] The load mean value of the same electric heating equipment at each sampling time in operation is defined as the rated power of the electric heating equipment.

[0013] Record the start and end times of each electric heating device in operation, and obtain the power consumption period of each electric heating device;

[0014] Step 4: Develop a group electric heating load peak time shifting strategy based on 01 integer linear programming to alleviate the overload problem in the substation area

[0015] 1) By assigning the power of the area meter Divide by the rated capacity of the transformer in the substation to obtain the overload rate of each substation at each sampling point at each sampling time (hereinafter referred to as each time point);

[0016] 2) According to the maximum overload rate of the substation relative to the set overload power limit of the transformer in the substation, the substation is judged as "substation operation safe", "substation operation overload" or "substation operation seriously overloaded";

[0017] 3) For the substations that output "substation operation overload" or "substation operation severe overload", the following strategies are activated to advance or lag the electricity usage sequence of some electric heating loads during the peak load period;

[0018] Based on the three requirements of household comfort, equal power consumption and electricity cost, the dispatch optimization model is subjected to equivalent operation constraints of peak shifting, peak-valley shifting, unchanged power before and after regulation, and peak shifting relay-regulation time limit:

[0019] Taking the minimum daily power of the area after the electric heating load is adjusted as the goal, the direct heating electric heating load group peak shifting scheduling model based on 01 integer linear programming to alleviate the overcapacity of the area is shown in formula (7):

[0020]

[0021] Where: is the electricity consumption identification variable after adjustment of the electric heating load group; N t It is the advance / lag period limit of the electric heating load set to ensure that the indoor temperature is within the comfortable temperature limit; It is the maximum daily power of the area meter after adjusting the electric heating load;

[0022] Among them, the adjusted area meter power is equal to the adjusted electric heating load group aggregate power plus the total residential load power, as shown in formula (6):

[0023]

[0024] Where: It is the power at each time point of the area meter after the electric heating load is adjusted; is the residential user power at time t; It is the daily maximum power of the area meter after the electric heating load is adjusted;

[0025] Step 5: Data coverage determines that the power consumption information of "station operation is safe" to reduce the amount of user adjustment

[0026] If it is determined as "safe operation of the substation", the substation is not over-capacitated. For the period when the substation is not over-capacitated, the power data of the substation meter before regulation is calculated using the dispatching model shown in formula (7): and the operating power of electric heating equipment i at sampling time t And the electricity consumption identification variable after the electric heating load group is adjusted Cover the current corresponding operation data, output the total power of the area meter and the aggregate power curve of the electric heating load group before and after the adjustment, observe the moving peak effect through the curve and output the switch status of each electric heating equipment that needs to be mobilized before and after the regulation;

[0027] Step 6: Output the electric heating equipment adjustment plan, prompt the area that is still overloaded after adjustment, and expand the transformer capacity

[0028] In order to guide the staff to implement the electric heating load scheduling plan, calculate and obtain the individual electric heating power adjustment of the electric heating household and the aggregate power adjustment of the electric heating load group of the electric heating household, and calculate the maximum daily power of the area after the electric heating load adjustment. And the capacity parameter S of the transformer in the substation tf , solve and obtain the maximum load rate of the area load after the electric heating load is adjusted, and then evaluate the overload state of the area after the electric heating load is adjusted;

[0029] By using formula (7), the optimal values ​​of all independent variables are solved at one time. The independent variables include the number i of the electric heating equipment to be adjusted, the time period when the electric heating equipment is controlled to be turned on or off, and the power of the area meter before the regulation. The power of the area meter after the regulation The power of the area meter after the regulation The maximum value is compared with the set overload power limit of the transformer in the substation area. If it is greater than the limit, it is judged that it is still over-capacity; if it is less than the limit, it is judged that there is no over-capacity problem after regulation;

[0030] Finally, the output is adjusted to form a peak load suppression effect diagram of the substation meter, which is composed of the number of electric heating household equipment, the optimization plan for the start and stop periods, including the time period information of controlled opening and controlled closing, the aggregated power adjustment amount of the electric heating load group of the electric heating household, and the comparison curve of the substation meter power before and after the load regulation. The substation number and the transformer overload rate that still have overcapacity after the electric heating load adjustment are counted and output. When the daily maximum power value of the substation meter is between 80% and 100% of the rated power of the substation transformer, it is displayed as to be expanded. When the daily maximum power value of the substation meter is above 100% of the rated power of the substation transformer, it is displayed as urgently needed to expand. This provides a basis for the precise expansion of the substation transformer and the orderly expansion of the urgent first and then the slow.

[0031] The step 2 is specifically as follows:

[0032] 1) Set 80% of the maximum capacity of the transformer in the substation as the heavy load power limit of the transformer in the substation;

[0033] 2) The larger value of the two values, the table power of the area and the aggregate power of the electric heating load group at the same sampling time, is used as the assigned table power of the area

[0034] The solution formula for the aggregate power of the electric heating load group is:

[0035]

[0036] In the formula, i is the number of the electric heating equipment; represents the operating power of electric heating equipment i at sampling time t;

[0037] 3) Calculate and obtain the residential user power at each sampling time according to the following formula; the residential user power is equal to the assigned area meter power Subtract the aggregate power of the electric heating load group:

[0038]

[0039] Where: It is the heavy load power limit of the transformer in the substation area; is the power of residential users at time t; i is the number of electric heating equipment.

[0040] The specific operation status of each electric heating device in step 3 is determined as follows:

[0041] On the power curve, the operating power of the electric heating equipment approaches 0, and returns to 0 after correction by the electric heating power disturbance limit. This is called the shutdown state or shutdown state, and is marked with 0; the operating power of the electric heating equipment does not approach 0, and fluctuates around the same mean value. This mean value is called the capacity Pe of the electric heating equipment. At the corresponding moment, the electric heating equipment is in operation, and is marked with 1.

[0042] The specific method for determining whether the area is "area operation safe", "area operation overload" or "area operation seriously overloaded" in step 4 is:

[0043] If the maximum overload rate of the area is lower than the overload power limit of the area transformer, the output is "area operation is safe";

[0044] If the maximum overload rate of the area is between the overload power limit of the area transformer and the maximum capacity of the area transformer, then "area operation overload" is output;

[0045] If the maximum overload rate of the substation is above the maximum capacity of the substation transformer, the output is "substation operation is seriously overloaded".

[0046] 5. In step 6, the formula for adjusting the power consumption of individual electric heating of electric heating households is:

[0047]

[0048] The formula for the aggregate power regulation of the electric heating load group of electric heating households is:

[0049]

[0050] The formula for the maximum load rate of the area load after electric heating load adjustment is:

[0051]

[0052] Where: It is the individual electric heating power adjustment of the electric heating household. They are the power regulation of individual and group-aggregated electric heating households; It is the operating status of the electric heating equipment before the electric heating load group is adjusted; is the operating state of the electric heating load group at the tth moment after adjustment; ξ is the maximum load rate of the area after load adjustment.

[0053] Through the above design scheme, the present invention can bring the following beneficial effects:

[0054] The present invention will ensure that the three household demands of "household comfort, same electricity consumption and electricity cost" are equivalent with the operation constraints of "peak shifting to peak-valley shifting, unchanged electricity before and after adjustment, peak shifting relay-adjustment time limit", etc., and take the minimum daily peak load as the goal to alleviate the overcapacity target of the substation, realize fast optimization and solution based on data cleaning and 01 integer linear programming method, and output the name of the individual user who wants to be adjusted, the optimization plan of the start and stop time period, the group aggregation adjustment power, the peak load suppression effect diagram, and count the substation numbers and the overload rate that are still overloaded after optimization and regulation, so as to provide theoretical support for the precise expansion of the transformer in the substation and the orderly expansion of the first urgent and then the slow. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0056] Figure 1 A comparison chart of the results of heavy overload power suppression in the substation area in the scenario where no capacity expansion is required in the present invention;

[0057] Figure 2 A comparison diagram of the results of heavy overload power suppression in the substation area under the scenario where capacity expansion can be temporarily postponed in the present invention;

[0058] Figure 3 This is a comparison chart of the heavy overload power suppression results in the substation area that is still in urgent need of capacity expansion in the present invention. DETAILED DESCRIPTION

[0059] A method for shifting the peak load of group electric heating suitable for alleviating the overload problem of a transformer area comprises the following steps, and the following steps are performed in sequence:

[0060] Step 1: With a 24-hour period, cyclically read the relevant user information obtained by the data supervision platform within 24 hours, and perform the operations of the subsequent steps once;

[0061] The data supervision platform is set to ensure that each area it supervises has only one transformer and one area meter for measuring the power of the transformer, each area has N users, and each user has only one electric heating device;

[0062] The user information includes the maximum capacity S of each transformer area tf , the power data P of each area meter at each sampling time tf , the number of electric heating equipment in each area N e2h 、Number of electric heating equipment in each area e2h , the electric heating equipment number corresponding to the electric heating equipment name, and the power data P of the electric heating load group at each sampling time e2h, where tf stands for transformer in the substation, and e2h is the abbreviation of electricity to heat; taking the sampling time interval of 15 minutes as an example, there are 96 sampling points in 24 hours, that is, the power data P of the substation in one cycle tf There are 96, the power data of the electric heating load group P e2h There are also 96. Because each user has only one electric heating device, the name of the electric heating device can also be considered as the user name.

[0063] Step 2: Preprocess data

[0064] 80% of the maximum capacity of the transformer in the substation is set as the heavy load power limit of the transformer in the substation, as shown in formula (1). The larger value of the two values ​​of the substation meter power and the electric heating load group aggregate power at the same sampling time is selected and assigned to the substation meter power as the assigned substation meter power. As shown in formula (2).

[0065] Calculate and obtain the residential user power at the sampling time t The residential user power is equal to the assigned area meter power Subtract the aggregate power of the electric heating load group, as shown in formula (3).

[0066]

[0067] Where: It is the heavy load power limit of the transformer in the substation area; is the residential user power at time t; i is the number of the electric heating equipment; represents the operating power of electric heating equipment i at sampling time t;

[0068] Step 3: Identify the electricity consumption period and equipment capacity Pe of each electric heating household

[0069] Through the historical operation data collected from each electric heating device, it can be observed that the power curve of each electric heating device presents two states. The first is that the operating power of the electric heating device is extremely small and close to 0. The value is corrected by the electric heating power disturbance limit and returns to 0. This is called the closed state or shutdown state. The second is that the operating power of the electric heating device is large and fluctuates slightly around the same mean value. This mean value is called the capacity Pe of the electric heating device. At the corresponding moment, the electric heating device is in operation. The operating state of the electric heating device is marked with 0 or 1, 0 means shutdown, and 1 means operation, as shown in formula (4);

[0070] Record the start and end times of each electric heating device in operation, and then obtain the power consumption period of each electric heating device;

[0071] The average load of the electric heating equipment with the same equipment number at each sampling time under the running state of 1 is defined as the rated power of the user's electric heating equipment. As shown in formula (5);

[0072]

[0073] Where: P error is the electric heating power disturbance limit; It is the operating status mark of the electric heating equipment before regulation, 0 means shutdown and 1 means operation; is the rated power of the electric heating equipment i.

[0074] The power consumption of the electric heating equipment can be obtained by multiplying the operating status identification value of the electric heating equipment by the capacity Pe of the electric heating equipment; the operating status identification of the electric heating equipment 0, 1 here is the theoretical basis for using 01 integer linear programming to formulate the control strategy in step 4.

[0075] Step 4: Establish a group electric heating load peak time shifting method based on 01 integer linear programming to alleviate the overload problem in the substation area

[0076] By assigning the power of the area meter Divided by the rated power of the transformer in the substation, the overload rate of each sampling point at each sampling time can be calculated. When the maximum overload rate is lower than the overload power limit of the transformer in the substation, "substation operation is safe" is output;

[0077] If the maximum overload rate is between the overload power limit of the transformer in the substation and the transformer capacity in the substation, the output is "substation operation overload";

[0078] If the maximum overload rate is above the transformer capacity of the substation, the output is "substation operation is seriously overloaded";

[0079] When it is identified that the substation is overloaded or seriously overloaded, the optimization strategy is activated to advance or lag the power usage sequence of some electric heating loads during the peak load period;

[0080] Based on the three requirements of household comfort, equal power consumption and electricity cost, the dispatch optimization model is subjected to equivalent operation constraints of peak shifting, peak-valley shifting, unchanged power before and after regulation, and peak shifting relay-regulation time limit:

[0081] The adjusted power of the area is equal to the adjusted aggregate power of the electric heating load group plus the total residential load power, as shown in formula (6):

[0082]

[0083] Where: It is the power at each time point of the area meter after the electric heating load is adjusted; Electric heating load group adjustment

[0084] The operating status at the tth moment after the holiday, 0 means shutdown, 1 means operation; It is the daily maximum power of the area meter after the electric heating load is adjusted;

[0085] Taking the minimum daily power of the area after the electric heating load is adjusted as the goal, the direct heating electric heating load group peak shifting scheduling model based on 01 integer linear programming to alleviate the overcapacity of the area is shown in formula (7):

[0086]

[0087] Where: N t It is the advance / lag period limit of the electric heating load set to ensure that the indoor temperature is within the comfortable temperature limit; It is the maximum daily power of the area meter after adjusting the electric heating load;

[0088] Step 5: Data coverage of electricity consumption information without transformer overcapacity problems to reduce user adjustment

[0089] According to formula (1), the transformer heavy load power limit of the substation is 0.8×S tf , determine the power of the area meter at time t Whether the transformer overload power limit of the substation is exceeded. If not, for the period when the substation is not overloaded, the power data of the substation table before the dispatching model is used to adjust the power of the substation Power and switch status data of electric heating equipment Cover the current operation data, output the total power of the area meter and the aggregate power curve of the electric heating load group before and after the adjustment, observe the moving peak effect and output the switch status of each electric heating equipment that needs to be mobilized before and after the regulation;

[0090] Step 6: Output the electric heating equipment adjustment plan and prompt the area that is still overloaded after adjustment to expand the transformer capacity in time

[0091] In order to guide the staff to implement the electric heating load scheduling plan, the individual electric heating power adjustment of the electric heating household and the aggregate power adjustment of the electric heating load group of the electric heating household are calculated and obtained. Among them, the individual electric heating power adjustment of the electric heating household is shown in formula (8) and the aggregate power adjustment of the electric heating load group of the electric heating household is shown in formula (9).

[0092] The maximum daily power of the area after adjusting the electric heating load And the capacity parameter S of the transformer in the substation tf, solve the maximum load rate of the area load after the electric heating load is adjusted, and then evaluate the overload state of the area after the electric heating load is adjusted. The maximum load rate of the area load after the electric heating load is adjusted is shown in formula (10):

[0093]

[0094] Where: It is the individual electric heating power adjustment of the electric heating household. They are the power regulation of individual and group-aggregated electric heating households; is the operating status of the electric heating equipment before the electric heating load group is adjusted, 0 means shutdown, 1 means operation; ξ is the maximum load rate of the area after load adjustment;

[0095] The function minimization sub-problem model under inequality constraints constructed by the objective function and constraint conditions of formula (7) can solve the optimal values ​​of all independent variables at one time. The independent variables include the number i of the electric heating equipment to be adjusted, the time period to be controlled to be turned on or off, and the power of the area meter before and after the regulation. The power of the area meter after the regulation The maximum value is equal to the heavy load power limit of the transformer in the area 0.8×S tf If it is greater than, it is still over-capacity, and if it is less than, there is no over-capacity problem after regulation. Among them, the period that needs to be controlled to open or close is calculated by the formula The result of this formula is obtained. If the result of this formula is 1, it means that the mark is controlled to be turned on, and if the result is -1, it means that the mark is controlled to be turned off.

[0096] Finally, the output is a peak load suppression effect diagram of the substation meter, which is composed of the equipment number of the household that adjusts the electric heating, the optimization plan for the start and stop periods, including the time period information of the controlled opening and controlled closing of the electric heating equipment, the aggregated power adjustment amount of the electric heating load group of the household that uses electric heating, and the comparison curve of the substation meter power before and after the load regulation. The substation number and the transformer overload rate that are still overloaded after the electric heating load is adjusted are counted and output. When the daily maximum power value of the substation meter is between 80% and 100% of the rated power of the substation transformer, it is displayed as to be expanded. When the daily maximum power value of the substation meter is above 100% of the rated power of the substation transformer, it is displayed as urgently needed to expand. This provides theoretical support for the precise expansion of the substation transformer and the orderly expansion of the urgent first and then the slow.

[0097] Example:

[0098] Three direct-heating rural electric heating substations with different overload levels are designed to fully verify the effectiveness and universality of the group electric heating load peak time shifting method proposed in this paper to alleviate the overload problem of the substation. tIt is the electric heating load advance / lag period limit set to ensure that the indoor temperature is within the comfortable temperature limit, and the value is 1 hour; the peak and valley period parameters are as follows:

[0099] Table 1 Peak and valley electricity price periods for electric heating load

[0100]

[0101] ①Read relevant user information from the data supervision platform

[0102] Read the heavy-load area number, area capacity, 96-point power data of the area table, number of electric heating equipment, name of electric heating equipment, and 96-point power data of the electric heating load group.

[0103] ②Preprocessing data

[0104] 80% of the transformer capacity in the substation is used as the heavy load power limit, as shown in formula (1). When the substation meter power < the aggregate power of the electric heating load group, the larger value of the two is assigned to the substation meter power, as shown in formula (2). The power of the residential user is calculated to be equal to the substation meter power minus the aggregate power of the electric heating load group, as shown in formula (3).

[0105] ③ Identify the electricity consumption period and equipment capacity Pe of each electric heating household

[0106] When the individual electric heating power is less than the disturbance limit, the electric heating equipment is marked as out of service. When the individual electric heating power is greater than the disturbance limit, the equipment is marked as in operation, as shown in formula (4). The load mean at each time point when the operation state is 1 is defined as the rated power of the user's electric heating equipment, as shown in formula (5).

[0107] ④ A method for shifting the peak time of group electric heating load based on 01 integer linear programming to alleviate the overload problem in the substation area

[0108] In order to facilitate the monitoring system to analyze the severity of overload in the substation before optimizing scheduling, it is necessary to calculate the overload rate at each time point. When the maximum overload rate is lower than 80%, the output substation is operating safely; when the maximum overload rate is between 80% and 100%, the output substation is operating overloaded; when the maximum overload rate is above 100%, the output substation is operating seriously overloaded.

[0109] The total power of the area after regulation is equal to the aggregate power of the electric heating load group after regulation plus the power of the residential load participating in the regulation, as shown in formula (6).

[0110] ⑤ When it is identified that there is an overload or severe overload problem in the substation, it is necessary to start the optimization strategy to advance or lag the electricity consumption sequence of some electric heating loads during the peak load period. In order to meet the electric heating electricity demand of three households such as "resident comfort, electricity consumption and electricity cost are the same", "peak shift peak-valley shift valley, unchanged electricity before and after adjustment, peak shift relay-adjustment time limit" can be used as the operation constraint of the scheduling optimization model. The target is the minimum power value of the substation table after the electric heating load is adjusted in one day. The peak shift scheduling model of the direct heating electric heating load group based on 01 integer linear programming to alleviate the overcapacity of the substation is shown in formula (7).

[0111] For the period when the area is not over-capacity, data coverage is carried out, and the area table and the total power curve of the electric heating equipment group before and after the adjustment are output to observe the moving peak effect. The time points before and after the electric heating of each household that needs to be adjusted are output.

[0112] ⑥ Output electric heating equipment adjustment plan, prompt the area that is still overloaded after adjustment to expand the transformer capacity in time

[0113] In order to guide the staff to implement the electric heating load scheduling plan, it is necessary to calculate the user power that needs to be adjusted for each electric heating device as shown in formula (8), and the group electric heating load aggregate adjustment power as shown in formula (9). In order to accurately evaluate the overload state of the area after the electric heating load is adjusted, it is necessary to solve the maximum load rate of the area load after the electric heating load is adjusted, as shown in formula (10).

[0114] ⑦ Design three direct-heating rural electric heating area calculation system with different overload levels to fully verify the effectiveness and versatility of the group electric heating load peak time shifting method proposed in this paper for alleviating the overload problem of the area. After being brought into the scheduling model for calculation, the output, start-stop period optimization plan, group aggregation adjustment power, peak load suppression effect diagram, and the area number and overload rate that are still overloaded after regulation.

[0115] The scheduling results show that Figure 1 After medium regulation, the peak load is 0-80%, and no capacity expansion is required; Figure 1 (a) is the power curve before the electric heating load is shifted and peak-cut without the need to expand the capacity of the station area; Figure 1 (b) is the power curve and total regulation power diagram after the electric heating load is time-shifted and peak-cut without the need to expand the capacity of the station area; Figure 1 (c) is a schematic diagram of the user names and control actions involved in time-shifting and peak-shaving of electric heating load without the need to expand the capacity of the station area. Figure 2 After medium regulation, the peak load is 80% to 100%, and capacity expansion can be temporarily postponed; Figure 2 (a) is the heavy overload power curve of the electric heating load before peak shaving in the area where capacity expansion can be postponed; Figure 2 (b) The power curve and total regulation power diagram of the electric heating load after time shifting and peak shaving in the area where capacity expansion can be postponed; Figure 2(c) is a schematic diagram of the user names and control actions involved in the time-shifting and peak-shaving of the electric heating load in the area where capacity expansion can be temporarily postponed. Figure 3 After medium regulation, the peak load is >100%, and capacity expansion is still urgently needed; Figure 3 (a) is the heavy overload power curve of the electric heating load before peak shaving in the area where capacity expansion is urgently needed; Figure 3 (b) The power curve and total regulation power diagram of the electric heating load after time shifting and peak shaving in the area where capacity expansion is urgently needed; Figure 3 (c) is a schematic diagram of the user names and control actions involved in the time-shifting and peak-shaving of the electric heating load in the area where capacity expansion is urgently needed.

[0116] Depend on Figure 1 (a) It can be seen that the transformer is the interactive device between the substation and the power grid. When the electric heating load surges in the severe winter, the total load peak of the substation will be large, exceeding the transformer overload power limit (i.e. 80% of the maximum capacity of the substation transformer). The transformer capacity and overload line value in the substation are marked with dotted lines.

[0117] Figure 1 (b) In order to reduce the load peak and avoid the problem of transformer burning caused by the peak load exceeding the transformer overload limit, the time-shiftable characteristics of the electric heating load are used. With the help of the electric heating load time-shifting strategy in this article, part of the electric heating load during the peak period is shifted back and forth to reduce the load peak. In order to more intuitively observe the suppression effect of the total load peak power (i.e., the table power of the area) before and after the electric heating load response regulation, the table power of the area before and after the electric heating load regulation is plotted respectively, and the difference between the two is the total regulation power of the cluster electric heating load.

[0118] Figure 1 (c) is to facilitate the distribution and execution of the control instructions for the cluster electric heating load, and the drawing intuitively shows the equipment number that needs to be adjusted and the time period of the controlled switch (corresponding to increase and decrease respectively).

[0119] The above examples illustrate the feasibility and effectiveness of the method for time-shifting group electric heating load peaks for alleviating the problem of overload in substations described in the present invention. It can be used to effectively smooth out peak loads in substations with different degrees of overload, and the output can be used together with the information on substation peak loads after regulation, providing theoretical support for the precise expansion of transformers in substations and the orderly expansion of the capacity from urgent to slow.

[0120] The above description is only a preferred example of the present invention and does not limit the present invention in any form. Simple modifications, equivalent changes or modifications made by those skilled in the art using the above disclosed technical contents all fall within the protection scope of the present invention.

Claims

1. A method for shifting the peak load of group electric heating, which is suitable for alleviating the overload problem in the substation, is characterized by: The process includes the following steps, which are performed in sequence: Step 1: Collect relevant user information obtained by the data supervision platform within 24 hours in a 24-hour cycle, and perform the operations of the subsequent steps once in a cycle; The data supervision platform is set to ensure that each area it supervises has only one transformer and one area meter for measuring the power of the transformer, each area has N users, and each user has only one electric heating device; The user information includes the maximum capacity S of each transformer area tf , the power data P of each area meter at each sampling time tf 、Number of electric heating equipment in each area e2h 、Number of electric heating equipment in each area e2h , corresponding to the electric heating equipment name and the electric heating equipment number, the power data P of the electric heating load group at each sampling time e2h , where tf stands for transformer, and e2h is the abbreviation of electricity to heat; Step 2: Set the heavy load power limit of the transformer in the substation area, obtain the assigned substation meter power at each sampling time and the residential user power at each sampling time; Step 3: Obtain the power curve of each electric heating device through the collected historical operation data of each electric heating device, and judge the operation status of each electric heating device through the power curve; the operation status of the electric heating device is marked with 0 or 1, 0 means shutdown, and 1 means operation; On the power curve, the operating power of the electric heating equipment in operation fluctuates around the same mean value, which is the capacity Pe of the electric heating equipment. The load mean value of the same electric heating equipment at each sampling time in operation is defined as the rated power of the electric heating equipment. Record the start and end times of each electric heating device in operation, and obtain the power consumption period of each electric heating device; Step 4: Develop a group electric heating load peak time shifting strategy based on 01 integer linear programming to alleviate the overload problem in the substation area 1) By assigning the power of the area meter Divide by the rated power of the transformer in the substation to obtain the overload rate of each substation at each sampling point at each sampling time; 2) According to the maximum overload rate of the substation relative to the set overload power limit of the transformer in the substation, the substation is judged as "substation operation is safe", "substation operation is overloaded" or "substation operation is seriously overloaded"; 3) For the output areas of "area operation overload" or "area operation seriously overload", the following strategies are activated to advance or lag the electricity usage sequence of some electric heating loads during the peak load period; Based on the three requirements of household comfort, equal power consumption and electricity cost, the dispatch optimization model is subjected to equivalent operation constraints of peak shifting, peak-valley shifting, unchanged power before and after regulation, and peak shifting relay-regulation time limit: Taking the minimum daily power of the area after the electric heating load is adjusted as the goal, the direct heating electric heating load group peak shifting scheduling model based on 01 integer linear programming to alleviate the overcapacity of the area is shown in formula (7): Where: is the electricity consumption identification variable after adjustment of the electric heating load group; N t It is the advance / lag period limit of the electric heating load set to ensure that the indoor temperature is within the comfortable temperature limit; It is the maximum daily power of the area meter after adjusting the electric heating load; Among them, the adjusted area meter power is equal to the adjusted electric heating load group aggregate power plus the total residential load power, as shown in formula (6): Where: It is the power of the area meter at each time point after the electric heating load is adjusted; is the residential user power at time t; It is the daily maximum power of the area meter after the electric heating load is adjusted; Step 5: Data coverage determines that the power consumption information of "station operation safety" is to reduce the amount of user adjustment If it is determined as "safe operation of the substation", the substation is not over-capacitated. For the period when the substation is not over-capacitated, the power data of the substation meter before regulation is calculated using the dispatching model shown in formula (7): and the operating power of electric heating equipment i at sampling time t And the electricity consumption identification variable after the electric heating load group is adjusted Cover the current corresponding operation data, output the total power of the area meter and the aggregate power curve of the electric heating load group before and after the adjustment, observe the moving peak effect through the curve and output the switch status of each electric heating equipment that needs to be mobilized before and after the regulation; Step 6: Output the electric heating equipment adjustment plan, prompt the area that is still overloaded after adjustment, and expand the transformer capacity In order to guide the staff to implement the electric heating load scheduling plan, calculate and obtain the individual electric heating power adjustment of the electric heating household and the aggregate power adjustment of the electric heating load group of the electric heating household, and calculate the maximum daily power of the area after the electric heating load adjustment. And the capacity parameter S of the transformer in the substation tf , solve and obtain the maximum load rate of the area load after the electric heating load is adjusted, and then evaluate the overload state of the area after the electric heating load is adjusted; By using formula (7), the optimal values ​​of all independent variables are solved at one time. The independent variables include the number i of the electric heating equipment to be adjusted, the time period when the electric heating equipment is controlled to be turned on or off, and the power of the area meter before the regulation. The power of the area meter after the regulation The power of the area meter after the regulation The maximum value is compared with the set overload power limit of the transformer in the substation area. If it is greater than the limit, it is judged that it is still over-capacity; if it is less than the limit, it is judged that there is no over-capacity problem after regulation; Finally, the output is adjusted to include the number of household electric heating equipment, the optimization plan for start and stop periods, including the time period information of controlled opening and controlled closing, the aggregated power adjustment amount of the electric heating load group of the electric heating household, and the comparison curve of the power of the substation meter before and after the load regulation. The substation number and transformer overload rate that are still overloaded after the electric heating load is adjusted are counted and output. The daily maximum power value of the substation meter is between 80% and 100% of the rated power of the substation transformer, indicating that expansion is pending. The daily maximum power value of the substation meter is above 100% of the rated power of the substation transformer, indicating that expansion is urgently needed, providing a basis for the precise expansion of the substation transformer and the orderly expansion of the urgent first and the slow later.

2. The method for shifting the peak load of group electric heating for alleviating the overload problem of the substation according to claim 1 is characterized by: The step 2 is specifically as follows: 1) Set 80% of the maximum capacity of the transformer in the substation as the heavy load power limit of the transformer in the substation; 2) The larger value of the two values, the table power of the area and the aggregate power of the electric heating load group at the same sampling time, is used as the assigned table power of the area The solution formula for the aggregate power of the electric heating load group is: In the formula, i is the number of the electric heating equipment; represents the operating power of electric heating equipment i at sampling time t; 3) Calculate and obtain the residential user power at each sampling time according to the following formula; the residential user power is equal to the assigned area meter power Subtract the aggregate power of the electric heating load group: Where: It is the heavy load power limit of the transformer in the substation area; is the residential user power at time t; i is the number of the electric heating equipment.

3. The method for shifting the peak load of group electric heating for alleviating the overload problem of the substation according to claim 1 is characterized by: The specific operation status of each electric heating device in step 3 is determined as follows: On the power curve, the operating power of the electric heating equipment approaches 0, and returns to 0 after correction by the electric heating power disturbance limit. This is called the shutdown state or shutdown state, and is marked with 0; the operating power of the electric heating equipment does not approach 0, and fluctuates around the same mean value. This mean value is called the capacity Pe of the electric heating equipment. At the corresponding moment, the electric heating equipment is in operation, and is marked with 1.

4. The method for shifting the peak load of group electric heating for alleviating the overload problem of the substation according to claim 1 is characterized by: The specific method for determining whether the area is "area operation safe", "area operation overload" or "area operation seriously overloaded" in step 4 is: If the maximum overload rate of the area is lower than the overload power limit of the area transformer, the output is "area operation is safe"; If the maximum overload rate of the area is between the overload power limit of the area transformer and the maximum capacity of the area transformer, then "area operation overload" is output; If the maximum overload rate of the substation is above the maximum capacity of the substation transformer, the output is "substation operation is seriously overloaded".

5. The method for shifting the peak load of group electric heating for alleviating the overload problem of the substation according to claim 1 is characterized by: In step 6, the formula for adjusting the power consumption of individual electric heating of electric heating households is: The formula for the aggregate power regulation of the electric heating load group of electric heating households is: The formula for the maximum load rate of the area load after electric heating load adjustment is: Where: It is the individual electric heating power adjustment of the electric heating household. They are the power regulation of individual and group-aggregated electric heating households; It is the operating status of the electric heating equipment before the electric heating load group is adjusted; is the operating state of the electric heating load group at the tth moment after adjustment; ξ is the maximum load factor of the substation after load regulation.

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