A method and system for evaluating security margin of a power spot market

Abstract

The application discloses a kind of electric power spot market safety margin evaluation method and system, obtain the clearing related data in the clearing cycle needing to carry out electric power spot market clearing safety margin evaluation;Input to the active static safety distance calculation model of pre-constructed electric power spot market clearing, calculate to obtain the active static safety distance of each time period unit output plan to each power transmission equipment;Determine the minimum value of the active static safety distance of each time period unit output plan to all power transmission equipment, obtain the minimum value index of static safety distance of unit output plan in clearing cycle;According to minimum value index, determine the average value of active static safety distance, obtain the average value index of static safety distance of unit output plan in clearing cycle;Calculate the grid safety margin comprehensive evaluation index under the environment of electric power spot market.The advantage: the safety margin of different clearing results can be accurately evaluated, and the grid safety operation guarantee capability under the environment of spot market is greatly improved.

Description

TECHNICAL FIELD

[0001] The application relates to a power spot market safety margin evaluation method and system, and belongs to the technical field of power system dispatch automation. BACKGROUND

[0002] Operation of the spot market has a wide and profound impact on the entire power industry. The power grid flow pattern under the spot market environment is quite different from that under the planning model. There are many power transaction participants, and each party may participate in power market transactions in various forms and adopt various bidding strategies to maximize their own interests, which will lead to variable power grid flow and make the system closer to the safe boundary, and there is a risk of safe operation of the system. The safety margin of the power grid is an important indicator in the operation of the power grid, and has been the focus of attention of power grid dispatching and operation personnel. Adequate safety margin is an important guarantee for the safe operation of the power grid under the action of various uncertain factors. Building a reasonable power grid safety margin evaluation index can guarantee the safety and efficiency of the operation of power grid equipment and improve the safe operation level of the power grid under the condition of the power spot market.

[0003] In the past, steady-state flow safety checking and static safety analysis were mostly carried out by using the point-by-point method. This method can only check point by point and cannot give the safety margin of the system. The safety margin of the line is usually measured by its load rate or available transmission capacity, but the load rate of some branches may be high, but the fluctuation of the system operation will not cause the flow to deviate significantly. These branches are actually very safe in operation. For active static safety margin evaluation, the security region analysis method can depict the feasible region formed by the set of system operating points that meet the operating conditions. By using the boundary information of the feasible region, it can not only judge whether the operating point is safe, but also give the distance from the operating point to the safety boundary as the evaluation index of the safety margin.

[0004] However, the safety margin evaluation under the spot market environment needs to consider multiple time periods of the calculation period. The existing method ignores the time sequence and trend of the power grid operation, divides the power grid operation into various separate time sections, does not consider the coupling constraints such as ramping between time periods when calculating the static safety distance, ignores the continuity of the power grid operation, and only analyzes the flow under a single time period. Therefore, the power grid cannot be evaluated as a whole, intuitively and effectively. SUMMARY

[0005] The technical problem to be solved by the application is to overcome the defects of the prior art and provide a power spot market safety margin evaluation method and system. The safety margin evaluation index of the power grid under the spot market environment is constructed according to the clearing result of the power spot market, which is convenient for operation personnel to understand the operation of the power grid in time, identify the safety risk of the clearing result of the spot market in advance, and improve the safety operation guarantee capability of the power grid under the market environment.

[0006] To solve the above technical problems, the present application provides 1. A power spot market safety margin evaluation method, comprising:

[0007] Obtaining the dispatch cycle that needs to carry out the dispatch safety margin evaluation of the power spot market, obtaining the load of each period in the dispatch cycle, obtaining the unit output limit, the line transmission limit, and the unit output plan of the dispatch of the power spot market;

[0008] Inputting the load, the unit output limit, the line transmission limit, and the unit output plan into a pre-constructed active static safety distance calculation model of the dispatch of the power spot market to calculate the active static safety distance from the unit output plan of each period to each transmission device;

[0009] The constraint conditions of the active static safety distance calculation model include system balance constraints, unit operation constraints, and power grid safety constraints; the optimization objective of the active static safety distance calculation model is to minimize the Euclidean distance between the unit output plan and the limit operating point of the transmission device;

[0010] According to the active static safety distance from the unit output plan of each period to each transmission device, the minimum value of the active static safety distance from the unit output plan of each period to all transmission devices is determined;

[0011] According to the minimum value of the active static safety distance from the unit output plan of each period to all transmission devices, the minimum value of the active static safety distance of all transmission devices is determined to obtain the minimum value index of the static safety distance of the unit output plan in the dispatch cycle; according to the minimum value of the active static safety distance from the unit output plan of each period to all transmission devices, the average value of the active static safety distance is determined to obtain the average value index of the static safety distance of the unit output plan in the dispatch cycle;

[0012] Based on the minimum value index and the average value index, the comprehensive evaluation index of the power grid safety margin in the power spot market environment is calculated.

[0013] Further, the constraint conditions are:

[0014]

[0015] Wherein, P i,t is the output of unit i at time t; P i,max , P i,min are the upper and lower limits of the output power of unit i; Δ i is the ramp rate of unit i; l i,t is the node load power; L j represents the upper limit of the branch j flow; M is the set of nodes calculated by the power grid; S i,j,tThe sensitivity of the injection power of node i to branch j; I is the number of units participating in dispatch in the system; L t The total load of the system at time t; S i,q,t The sensitivity of the injection power of node i to the power transmission equipment q to be calculated for the active static security distance; L q Indicates the power flow limit of the power transmission equipment q.

[0016] Further, the objective function of the optimization objective is:

[0017]

[0018] Wherein, D q,t The active static security distance of the unit output plan at time t to the qth power transmission equipment; P i,t Is an extreme operating point vector to be solved to satisfy the qth constraint; P 0 i,t The unit output plan vector obtained by clearing.

[0019] Further, the minimum value index of the static security distance of the unit output plan in the clearing cycle is represented as:

[0020] D min = min{D1,D2,...D t ,...,D T}

[0021] Wherein, D min The minimum value index of the static security distance of the unit output plan in the clearing cycle, D t The minimum value of the active static security distance of the unit output plan at time t to all power transmission equipment, t = 1, 2, …, T, T is the number of time periods included in the clearing calculation of the spot market.

[0022] Further, the average value index of the static security distance of the unit output plan in the clearing cycle is represented as:

[0023]

[0024] Wherein, D avg The average value of the static security distance of the unit output plan in the clearing cycle.

[0025] Further, the comprehensive evaluation index of the power grid safety margin in the electricity spot market environment is represented as:

[0026]

[0027] Wherein, D s The safety margin comprehensive evaluation index of the clearing example s of the spot market; D maxK is the normalized standard distance for static safety distance; K takes an integer less than 1.

[0028] A safety margin assessment system for the electricity spot market, comprising:

[0029] The acquisition module is used to acquire the clearing period for which a safety margin assessment of the electricity spot market clearing needs to be carried out, acquire the load and reserve demand for each period within the clearing period, acquire the unit output limit and the line transmission limit, and acquire the unit output plan for the electricity spot market clearing.

[0030] The calculation module is used to input the previously obtained load, unit output limit, line transmission limit, and unit output plan into the pre-built active static safety distance calculation model for the clearing of the electricity spot market, and calculate the active static safety distance from the unit output plan to each transmission equipment for each time period.

[0031] The constraints of the active power static safety distance calculation model include: system balance constraints, unit operation constraints, and power grid safety constraints; the optimization objective of the active power static safety distance calculation model is to minimize the Euclidean distance between the unit output plan and the transmission equipment at the limit operation point.

[0032] The indicator determination module is used to determine the minimum active static safety distance from the unit output plan to all transmission equipment in each time period based on the active static safety distance from the unit output plan to each transmission equipment in each time period, thereby obtaining the minimum static safety distance indicator of the unit output plan within the clearing cycle; and to determine the average active static safety distance based on the active static safety distance from the unit output plan to each transmission equipment in each time period, thereby obtaining the average static safety distance indicator of the unit output plan within the clearing cycle.

[0033] The evaluation module is used to calculate a comprehensive evaluation index of grid security margin under the electricity spot market environment based on the minimum value index and the average value index.

[0034] A computer-readable storage medium storing one or more programs, said one or more programs including instructions that, when executed by a computing device, cause the computing device to perform any of the methods described.

[0035] A computing device, comprising,

[0036] One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for performing any of the methods described.

[0037] The beneficial effects achieved by this invention are as follows:

[0038] 1) Based on the clearing results of the spot market, and taking into account various factors related to the static safety margin of the power grid, a static safety distance assessment model considering time-period coupling is established to obtain the power grid safety margin under the spot market environment;

[0039] 2) It proposes minimum and average values ​​for static safety distance in multiple time periods under the spot market environment, evaluates the static safety margin in multiple time periods from multiple different perspectives, ensures the rationality of the assessment results, and avoids the one-sidedness of assessment caused by a single indicator.

[0040] 3) The minimum and average values ​​and other dispersed indicators were integrated to construct a comprehensive evaluation index for the safety margin of the clearing cycle based on a nonlinear exponential function. The evaluation index is also more likely to characterize the safety margin level of different clearing results.

[0041] This invention evaluates the power grid safety margin under the spot market operating environment, can prevent the safety risks of spot market clearing results in advance, can deeply perceive the safety boundary of clearing results under the current operating environment, and can accurately evaluate the safety margin of different clearing results, thus greatly improving the power grid's ability to ensure safe operation under the spot market environment. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the safety margin assessment method for the electricity spot market of the present invention. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0044] like Figure 1 As shown, this invention discloses a method for assessing the safety margin of the electricity spot market. Below is a preferred embodiment of this invention, which includes a safety margin assessment process for a day-ahead spot market using the method of this invention. Its features, objectives, and advantages can be seen from the description of the embodiments.

[0045] The clearing mechanism of the electricity spot market is based on the market member declaration information and the grid operation boundary conditions, and uses the security constrained unit commitment (SCUC) and the security constrained economic dispatch (SCED) program for optimization calculation, and after the alternating current safety check, the market transaction results are cleared, including the output curve and price of the generator set. The clearing result under the environment of the spot market contains multiple operation periods. Taking the day-ahead market as an example, every 15 minutes is a calculation period, and the clearing result contains 96 periods. At this time, the safety margin assessment under the environment of the electricity spot market is carried out, the online automatic calculation and analysis of the safety margin of the electricity spot market clearing are realized, the safety risk of the clearing result is identified in advance by the operation personnel, and the safety operation guarantee capability of the grid under the market environment is improved.

[0046] The grid operation state is constantly changing, and each period operation point has its own operation state and operation trend. In the past, the safety margin assessment based on the static safety distance usually only considers the operation state information of the current section, and ignores the continuity of the grid operation, and only analyzes the static safety under a single power flow section. The actual grid operation state is changing all the time, and the operation state information at each moment can be regarded as an information point. The continuous grid operation state can be regarded as the process of the information point continuously operating in the operation space, and the connection of the information points in sequence can depict the operation trajectory of the grid.

[0047] The method comprises the following steps:

[0048] 1) Data preparation, obtaining the load and reserve demand of the 96 periods of the day-ahead market of the electricity spot market, obtaining the unit output limit, obtaining the line transmission limit, and obtaining the unit output plan of the electricity spot market clearing;

[0049] 2) Constructing an active static safety distance calculation model of the electricity spot market clearing, and calculating the active static safety distance from the unit output plan to each transmission device in each period;

[0050] The constraint conditions of the optimization model include: system balance constraint, unit operation constraint and grid safety constraint:

[0051]

[0052] Wherein, P i,t is the output of unit i at time t; P i,max , P i,min are the upper and lower limits of the output power of unit i; Δ i is the climbing rate of unit i; l i,t is the node load power; L j represents the power flow upper limit of branch j; M is the set of nodes of the grid; S i,j,t is the sensitivity of the injection power of node i to branch j; I is the number of units participating in dispatch in the system; Lt is the total load of the system at time t. Calculate the active static security distance of the unit output plan in period t to the transmission device q, S i,q,t is the injection power of node i to the sensitivity of transmission device q; L q represents the flow limit of transmission device q.

[0053] The optimization objective is to minimize the Euclidean distance between the unit output plan and the limit operating point of the transmission device:

[0054]

[0055] where D q,t is the static security distance of the unit output plan in period t to the qth transmission device; P i,t is an extreme operating point vector to be solved that satisfies the qth constraint; P 0 i,t is the unit output plan vector in period t obtained by clearing.

[0056] 3) Obtain the active static security distance of each period of the electricity spot market, and construct the time series of the active static security distance of the electricity spot market: the minimum value of the active static security distance of the unit output plan in a single period to all transmission devices is the active static security distance of the unit output plan in that period;

[0057] The time series of the static security distance is:

[0058] D = {D1, D2,..., D t ..., D T}

[0059] where D is the static security distance vector of the calculation period of the spot market; D t is the active static security distance of period t; T is the number of periods included in the clearing calculation of the spot market.

[0060] 4) Calculate the minimum value index and the average value index of the active static security distance of all periods in the clearing period, which are used to evaluate the extreme value and distribution of the static security distance of the unit output plan in the clearing period;

[0061] The minimum static security distance index of the clearing period is: D min = min{D1, D2,..., D t ..., D T}, where D min is the minimum static security distance of the clearing result of the spot market; The average static security distance index of the clearing period is: where D avg is the average static security distance of the clearing result of the spot market.

[0062] 5) Based on the minimum and average static safety distance indicators of the unit output plan during the clearing period, calculate the comprehensive evaluation index of grid safety margin under the electricity spot market environment, and the evaluation ends.

[0063] The comprehensive indicators for assessing the safety margin of the electricity spot market are: Among them, D s A comprehensive evaluation index for the safety margin of clearing cases in the spot market; D max This is the normalized standard distance for static safety distance; K takes an integer less than 1. When K takes a small value (0, 0.2), D... s The decay trend is quite obvious. When K takes a large value (0.8, 1), D s The decline trend is relatively gradual.

[0064] Analysis of the evaluation results reveals that due to varying grid operating conditions at different times during the spot market clearing, the static safety distance differs across time periods. The period with the smallest static safety distance is the key period affecting the safety margin of the clearing results. Analysis shows that the system load is highest during the period with the smallest static safety distance, and the power flow load rate of each branch is relatively high, resulting in a lower grid safety margin. Therefore, the static safety distance can effectively assess the grid safety margin of the spot market clearing results, providing operators with an effective and direct evaluation method. Further analysis of the effectiveness of the comprehensive indicator evaluation shows that the smaller the minimum and average static safety distances for each time period of the spot market clearing results, the lower the grid safety margin assessment, accurately reflecting the overall safety margin level of the grid across multiple time periods under the spot market environment.

[0065] This method enables a comprehensive evaluation and automatic calculation of the power grid safety margin in a spot market environment. It does not require a large amount of human intervention, and the calculation speed can meet the needs of practical applications. It effectively solves the problems of traditional power grid safety margin assessment, which requires a large amount of human intervention, relies on experience, is inefficient, and is difficult to effectively consider the multi-time-coupling operation of the electricity spot market. It has broad prospects for promotion.

[0066] Accordingly, the present invention also provides a method for assessing the safety margin of the electricity spot market, characterized in that it includes:

[0067] Obtain the clearing period for which a safety margin assessment of the electricity spot market clearing needs to be conducted, obtain the load and reserve demand for each period within the clearing period, obtain the unit output limit and line transmission limit, and obtain the unit output plan for the electricity spot market clearing;

[0068] The load, the unit output limit, the line transmission limit and the unit output plan obtained previously are input into a pre-constructed active static security distance calculation model of the power spot market clearing, and active static security distances of the unit output plan to each transmission device in each period are calculated;

[0069] The constraint conditions of the active static security distance calculation model include system balance constraints, unit operation constraints and power grid security constraints, and the optimization objective of the active static security distance calculation model is to minimize the Euclidean distance between the unit output plan and the limit operation point of the transmission device;

[0070] The minimum value of the active static security distances of the unit output plan to all transmission devices in each period is determined according to the active static security distances of the unit output plan to each transmission device in each period, and the minimum value index of the static security distance of the unit output plan in the clearing period is obtained; the average value of the active static security distance is determined according to the minimum value index of the static security distance of the unit output plan in the clearing period, and the average value index of the static security distance of the unit output plan in the clearing period is obtained;

[0071] Based on the minimum value index and the average value index, a comprehensive evaluation index of the power grid security margin in the power spot market environment is calculated.

[0072] Correspondingly, the application also provides a computer readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform any of the methods described above.

[0073] Correspondingly, the application also provides a computing device, including,

[0074] one or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for performing any of the methods described above.

[0075] Those skilled in the art will understand that embodiments of the application can be provided as methods, systems, or computer program products. Therefore, the application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage media, etc.) containing computer-usable program code.

[0076] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0077] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0078] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0079] The above only is the preferred embodiment of the present application, it should be pointed out that, for those skilled in the technical field, without departing from the technical principles of the present application, can also make a number of improvements and variations, these improvements and variations should also be considered as the protection scope of the present application.

Claims

1. A method for assessing the safety margin of the electricity spot market, characterized in that, include: Obtain the clearing period for which a safety margin assessment of the electricity spot market clearing needs to be conducted, obtain the load for each period within the clearing period, obtain the unit output limit, the transmission line limit, and the unit output plan for the electricity spot market clearing; The load, unit output limit, line transmission limit, and unit output plan are input into a pre-built active static safety distance calculation model for the clearing of the electricity spot market, and the active static safety distance from the unit output plan to each transmission equipment in each time period is calculated. The constraints of the active power static safety distance calculation model include: system balance constraints, unit operation constraints, and power grid safety constraints; the optimization objective of the active power static safety distance calculation model is to minimize the Euclidean distance between the unit output plan and the transmission equipment at the limit operation point. The minimum value of the active static safety distance from the unit output plan to all transmission equipment in each time period is determined based on the active static safety distance from each unit output plan to each transmission equipment in each time period. Based on the minimum active power static safety distance from the generating units' planned output to all transmission equipment in each time period, the minimum active power static safety distance of all transmission equipment is determined, thus obtaining the minimum static safety distance index of the generating units' planned output within the clearing cycle. ,in, D min The minimum static safety distance indicator for the unit's output plan during the clearing cycle. D t For time period t The minimum active static safety distance from the unit's planned output to all transmission equipment. t= 1,2,…, T , T The number of time periods included in the calculation for spot market clearing; The average active power static safety distance is determined based on the minimum active power static safety distance from the planned unit output to all transmission equipment in each time period, thus obtaining the average static safety distance index of the planned unit output during the clearing cycle. ,in, D avg The average static safety distance of the unit's planned output during the clearing cycle; Based on the minimum value index and the average value index, a comprehensive assessment index for grid security margin in the electricity spot market environment is calculated. ,in, D s Settlement rules for the spot market s Comprehensive evaluation index of safety margin; D max K is the normalized standard distance for static safety distance; K takes an integer less than 1.

2. The method for assessing the safety margin of the electricity spot market according to claim 1, characterized in that, The constraints are as follows: ； in, P i,t For the unit i exist t Efforts made at all times; P i,max , P i,min The units i Upper and lower limits of output power; ∆ i For the unit i The rate of ascent; l i,t For node load power; L j Indicates a branch j The upper limit of the trend; M It is the set of computing nodes for the power grid; S i,j,t For nodes i Injected power for branch j Sensitivity; I This represents the number of units participating in scheduling within the system. L t For the system t Total load at any given time; S i,q,t For nodes i The injected power is for the transmission equipment for which the active static safety distance is to be calculated. q Sensitivity; L q Indicates power transmission equipment q The trend is limited.

3. The method for assessing the safety margin of the electricity spot market according to claim 1, characterized in that, The objective function for the optimization objective is: ;in, D q,t for t The planned output of the generator units during the specified period will be up to the next period. q Active static safety distance of transmission equipment; P i,t It is the unmet need. q A vector of extreme running points under one constraint; P 0 i,t Obtained from clearing t Time-period unit output plan vector.

4. A safety margin assessment system for the electricity spot market, characterized in that, include: The acquisition module is used to acquire the clearing period for which a safety margin assessment of the electricity spot market clearing needs to be carried out, acquire the load and reserve demand for each period within the clearing period, acquire the unit output limit and the line transmission limit, and acquire the unit output plan for the electricity spot market clearing. The calculation module is used to input the previously obtained load, unit output limit, line transmission limit, and unit output plan into the pre-built active static safety distance calculation model for the clearing of the electricity spot market, and calculate the active static safety distance from the unit output plan to each transmission equipment for each time period. The constraints of the active power static safety distance calculation model include: system balance constraints, unit operation constraints, and power grid safety constraints; the optimization objective of the active power static safety distance calculation model is to minimize the Euclidean distance between the unit output plan and the transmission equipment at the limit operation point. The indicator determination module is used to determine the minimum active static safety distance from the planned unit output to all transmission equipment for each time period based on the active static safety distance from the planned unit output to each transmission equipment for each time period, thus obtaining the minimum static safety distance indicator of the planned unit output within the clearing cycle. ,in, D min The minimum static safety distance indicator for the unit's output plan during the clearing cycle. D t For time period t The minimum active static safety distance from the unit's planned output to all transmission equipment. t= 1,2,…, T , T The number of time periods included in the calculation for spot market clearing; The average active power static safety distance is determined based on the minimum active power static safety distance from the planned unit output to all transmission equipment in each time period, thus obtaining the average static safety distance index of the planned unit output during the clearing cycle. ,in, D avg The average static safety distance of the unit's planned output during the clearing cycle; Based on the minimum value index and the average value index, a comprehensive assessment index for grid security margin in the electricity spot market environment is calculated. ,in, D s Settlement rules for the spot market s Comprehensive evaluation index of safety margin; D max K is the normalized standard distance for static safety distance; K takes an integer less than 1.

5. A computer-readable storage medium for storing one or more programs, characterized in that, The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods according to claims 1 to 3.

6. A computing device, characterized in that, include, One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods according to claims 1 to 3.

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