Power distribution network dominant demand response mode selection method, system, equipment and medium

Abstract

The invention belongs to the field of power distribution network operation, and discloses a power distribution network dominant demand response mode selection method, system and device and a medium, and the method comprises the steps: generating a division result of a demand response trigger signal event according to an event demand judgment criterion of a power distribution network operation state; calculating priority indexes of various demand response trigger signal events to obtain priority index evaluation values; scoring the feature indexes according to an evaluation criterion to obtain feature index scoring results, and summing the feature index scoring results to obtain a comprehensive coefficient; and comparing and judging the comprehensive value of the operation trigger signal of the power distribution network to obtain a to-be-solved operation event of the power distribution network so as to define a dominant demand response mode of the power distribution network. According to the power distribution network dominant demand response mode selection method provided by the invention, the operation problem in the power distribution network is comprehensively judged based on the actually measured data, and the demand response mode selection under the complex operation state of the power distribution network is realized in combination with the proposed criterion.

Description

Technical Field

[0001] The present invention relates to the field of distribution network operation, and in particular to a method, system, device and medium for selecting a dominant demand response mode of a distribution network. Background Art

[0002] With the advancement of the construction of new power systems, distributed energy such as photovoltaics and wind turbines are connected to the distribution system on a large scale, and the integration and interaction of source-grid-load-storage in the system are strengthened, but at the same time, the randomness and volatility of the distribution network operation are greatly increased. Since the access of distributed sources and loads will affect the operational stability of the distribution network, the distribution network needs to regulate resources in the region to respond to demand and improve the operation level of the distribution network. However, in the actual operation of the distribution network, due to the diversity of operational problems, there are many demand response tasks, such as voltage over-limit management and reducing network losses. Traditional distribution network management is difficult to make a global comprehensive judgment based on the real-time operation data of the distribution network, and it is impossible to select the demand response mode efficiently. The current distribution network management urgently needs a more scientific demand response mode selection method to improve the scientificity and effectiveness of decision-making in the operation and control of the distribution network.

[0003] At present, there have been studies on demand response strategies for distribution network operation. The common method is to establish corresponding demand response strategies for controllable loads such as electric vehicle charging stations, large industrial users with energy storage, and air conditioning clusters to improve the distribution network's control capabilities and operational flexibility. At present, the focus of research on demand response strategies for distribution network operation is on various controllable resource control strategies under a single demand response mode. However, these strategies are often not flexible enough and cannot effectively respond to the multi-type demand response needs generated during the operation of the distribution network. There is still a lack of methods for efficient selection of multi-type operating problems during the operation of the distribution network based on real-time data. If a more scientific demand response mode selection method is not proposed for the operation of the distribution network, it will affect the operation and control efficiency of the distribution network, resulting in reduced user satisfaction and economic losses, and restricting the further construction and development of new power systems.

[0004] Therefore, how to provide a method, system, equipment and medium for selecting a dominant demand response mode in a distribution network is an urgent problem to be solved. Summary of the invention

[0005] The embodiments of the present invention provide a method, system, device and medium for selecting a dominant demand response mode of a distribution network to solve the problem in the prior art that it is difficult to make a global comprehensive judgment based on the real-time operation data of the distribution network.

[0006] In order to have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended to be a general review, nor is it intended to identify key / important components or to delineate the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a preface to the detailed description that follows.

[0007] According to a first aspect of an embodiment of the present invention, a method for selecting a dominant demand response mode in a distribution network is provided.

[0008] In one embodiment, the distribution network-led demand response mode selection method includes:

[0009] Acquire the real-time operation monitoring data of the distribution network, obtain the distribution network operation status according to the predefined trigger condition criteria of the distribution network operation trigger signal, and generate the division result of the demand response trigger signal event according to the event demand judgment criteria of the distribution network operation status;

[0010] Calculate the priority index of each type of demand response trigger signal event, obtain the priority index evaluation value, and perform priority evaluation on each type of demand response trigger signal event based on the priority index evaluation value;

[0011] Based on the evaluation results, an evaluation criterion for the characteristic indicators is defined, and the characteristic indicators are scored according to the evaluation criterion to obtain a characteristic indicator scoring result, and the characteristic indicator scoring results are summed to obtain a comprehensive coefficient;

[0012] The weight coefficient of the characteristic index is calculated based on the comprehensive coefficient, and the comprehensive value of the distribution network operation trigger signal is compared and judged according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network.

[0013] In one embodiment, the real-time operation monitoring data of the distribution network is obtained, the operation status of the distribution network is obtained according to the trigger condition criteria of the predefined distribution network operation trigger signal, and the division result of the demand response trigger signal event is generated according to the event demand judgment criteria of the distribution network operation status, including:

[0014] Acquire the real-time operation monitoring data of the distribution network, extract the data information of various demand response trigger signal events from the real-time operation monitoring data of the distribution network, and obtain the operation status of the distribution network according to the trigger condition criteria of the predefined distribution network operation trigger signal;

[0015] Based on the data information of various demand response trigger signal events, the judgment criteria of various demand response trigger signal events are defined to obtain the trigger signals corresponding to various demand response trigger signal events;

[0016] A distribution network node set is generated based on the trigger signal, and the distribution network operation status is divided based on the distribution network node set.

[0017] In one embodiment, the demand response trigger signal event includes voltage over-limit, network loss, grid frequency, line overload and peak load filling;

[0018] The characteristic indicators contained in the priority indicator include an impact range indicator, a duration indicator, a change amplitude indicator, a loss cost indicator and a node access load indicator.

[0019] In one embodiment, the calculation formula of the priority index of the demand response trigger signal event is:

[0020] G i =ω1Z i +ω2T i +ω3C i +ω4A i +ω5B i i∈Q;

[0021] In the formula, G i is the priority index of the demand response trigger signal event occurring at node i; Z i is the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index; Q is the set of distribution network nodes with trigger signals.

[0022] In one embodiment, the evaluation criteria of the characteristic indicators are defined based on the evaluation results, and the characteristic indicators are scored according to the evaluation criteria to obtain the characteristic indicator scoring results, including:

[0023] Calculate the characteristic indicators contained in the priority indicators based on the evaluation results, and define the evaluation criteria of the characteristic indicators based on the characteristic indicator calculation results;

[0024] The characteristic indicators are scored based on the evaluation criteria of the characteristic indicators to obtain the characteristic indicator scoring results, so as to achieve the standardization and unification of the characteristic indicators.

[0025] In one embodiment, the weight coefficient of the characteristic index is calculated based on the comprehensive coefficient, and the comprehensive value of the distribution network operation trigger signal is compared and judged according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network, including:

[0026] Calculate the weight coefficient of the characteristic indicator based on the evaluation criteria and comprehensive coefficient of the characteristic indicator, and calculate the comprehensive value of the trigger signal corresponding to the demand response trigger signal event;

[0027] The comprehensive values ​​of the trigger signals are compared and judged, and the demand response trigger signal event corresponding to the largest comprehensive value of the trigger signal is selected as the distribution network operation event to be resolved in the preset time period to clarify the dominant demand response mode of the distribution network.

[0028] In one embodiment, the calculation formula of the weight coefficient of the characteristic index is:

[0029]

[0030] In the formula, S i Represents the comprehensive coefficient of characteristic indicators; Z i is the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index respectively.

[0031] According to a second aspect of an embodiment of the present invention, a distribution network dominant demand response mode selection system is provided.

[0032] In one embodiment, the distribution network-led demand response mode selection system comprises:

[0033] The trigger signal judgment and event classification module is used to obtain the real-time operation monitoring data of the distribution network, obtain the distribution network operation status according to the predefined distribution network operation trigger signal trigger condition criteria, and generate the division result of the demand response trigger signal event according to the event demand judgment criteria of the distribution network operation status;

[0034] A trigger signal priority evaluation module is used to calculate the priority index of various demand response trigger signal events, obtain the priority index evaluation value, and perform priority evaluation on various demand response trigger signal events based on the priority index evaluation value;

[0035] The priority indicator scoring calculation module is used to define the evaluation criteria of the characteristic indicators based on the evaluation results, and score the characteristic indicators according to the evaluation criteria to obtain the characteristic indicator scoring results, and sum the characteristic indicator scoring results to obtain the comprehensive coefficient;

[0036] The indicator weight coefficient calculation module is used to calculate the weight coefficient of the characteristic indicator based on the comprehensive coefficient, and compare and judge the comprehensive value of the distribution network operation trigger signal according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network.

[0037] In one embodiment, the trigger signal judgment and event classification module includes a trigger signal definition module, a trigger signal generation module and a trigger signal event classification module, wherein:

[0038] The trigger signal definition module is used to obtain the real-time operation monitoring data of the distribution network, extract the data information of various demand response trigger signal events from the real-time operation monitoring data of the distribution network, and obtain the distribution network operation status according to the predefined trigger condition criteria of the distribution network operation trigger signal;

[0039] A trigger signal generation module is used to define the judgment criteria of various demand response trigger signal events based on the data information of various demand response trigger signal events, and obtain the trigger signals corresponding to various demand response trigger signal events;

[0040] The trigger signal event division module is used to generate a distribution network node set based on the trigger signal, and to realize the division of the distribution network operation status based on the distribution network node set.

[0041] In one embodiment, the demand response trigger signal event includes voltage over-limit, network loss, grid frequency, line overload and peak load filling;

[0042] The characteristic indicators contained in the priority indicator include an impact range indicator, a duration indicator, a change amplitude indicator, a loss cost indicator and a node access load indicator.

[0043] In one embodiment, the calculation formula of the priority index of the demand response trigger signal event is:

[0044] G i =ω1Z i +ω2T i +ω3C i +ω4A i +ω5B i i∈Q;

[0045] In the formula, G i is the priority index of the demand response trigger signal event occurring at node i; Z iis the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index; Q is the set of distribution network nodes with trigger signals.

[0046] In one embodiment, the priority index scoring calculation module includes an evaluation criteria definition module and a feature index scoring module, wherein:

[0047] An evaluation criteria definition module is used to calculate the characteristic indicators contained in the priority indicators based on the evaluation results, and define the evaluation criteria of the characteristic indicators based on the characteristic indicator calculation results;

[0048] The feature indicator scoring module is used to score the feature indicators based on the feature indicator evaluation criteria and obtain the feature indicator scoring results to achieve standardization and unification of the feature indicators.

[0049] In one embodiment, the indicator weight coefficient calculation module includes a comprehensive value calculation module and a demand response mode clarification module, wherein:

[0050] A comprehensive value calculation module, used to calculate the weight coefficient of the characteristic indicator based on the evaluation criteria and comprehensive coefficient of the characteristic indicator, and calculate the comprehensive value of the trigger signal corresponding to the demand response trigger signal event;

[0051] The demand response mode clarification module is used to compare and judge the comprehensive value of the trigger signal, select the demand response trigger signal event corresponding to the largest comprehensive value of the trigger signal as the distribution network operation event to be resolved in the preset time period, so as to clarify the dominant demand response mode of the distribution network.

[0052] In one embodiment, the calculation formula of the weight coefficient of the characteristic index is:

[0053]

[0054] In the formula, S i Represents the comprehensive coefficient of characteristic indicators; Z i is the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; iB is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index respectively.

[0055] According to a third aspect of an embodiment of the present invention, a computer device is provided.

[0056] In one embodiment, the computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0057] According to a fourth aspect of embodiments of the present invention, a computer-readable storage medium is provided.

[0058] In one embodiment, the computer-readable storage medium stores a computer program, and the computer program implements the steps of the above method when executed by a processor.

[0059] The technical solution provided by the embodiment of the present invention may have the following beneficial effects:

[0060] 1. The distribution network dominant demand response mode selection method provided by the present invention makes a comprehensive judgment on the operation problems in the distribution network based on the measured data, and combines the proposed criteria to realize the selection of the demand response mode under the complex operation state of the distribution network.

[0061] 2. The present invention takes into account the power characteristics of sources and loads and the characteristics of their temporal and spatial distribution, and proposes five types of distribution network demand-side response events, namely, voltage over-limit events, network loss events, grid frequency events, line overload events, and peak shaving and valley filling events, and develops alternative modes for multi-dimensional demand response in distribution network operation.

[0062] 3. The present invention considers the analysis of the distribution network operation characteristics of the interaction between distributed energy and load, calculates the priority indicators of signal nodes triggered by various events, fully explores the characteristics of demand response in terms of impact range, duration, change amplitude, loss cost and node load, and realizes the comprehensive evaluation of demand response events.

[0063] 4. The present invention can dynamically adapt to changes in the operating status of the distribution network through multi-dimensional judgment of demand-side response events, and more accurately reflect the operating environment and demand changes of the distribution network in practical applications. Through systematic priority evaluation and comprehensive analysis, it can comprehensively evaluate and optimize demand response strategies, and effectively improve the response speed and processing capabilities to emergencies. The distribution network dominant demand response mode selection method provided by the present invention has a wide range of applications and can be applied to the field of power systems to improve the efficiency and flexibility of distribution network operation demand response decisions in power systems.

[0064] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0066] Figure 1 is a flow chart of a method for selecting a dominant demand response mode in a distribution network according to an exemplary embodiment;

[0067] Figure 2 is a principle block diagram of a distribution network dominant demand response mode selection system according to an exemplary embodiment;

[0068] Figure 3 is a structural schematic diagram of a computer device according to an exemplary embodiment;

[0069] Figure 4 is a schematic diagram of an implementation of a method for selecting a dominant demand response mode in a distribution network according to an exemplary embodiment;

[0070] Figure 5 It is a schematic diagram of dividing demand response trigger signal events in a method for selecting a dominant demand response mode in a distribution network according to an exemplary embodiment;

[0071] Figure 6 is a schematic diagram of priority characteristic indicators in a method for selecting a dominant demand response mode in a distribution network according to an exemplary embodiment;

[0072] Figure 7 It is a schematic diagram of a change trend of a weight coefficient corresponding to a priority characteristic indicator in a method for selecting a dominant demand response mode of a distribution network according to an exemplary embodiment;

[0073] Figure 8 The present invention is a schematic diagram of decision-making of distribution network operation events to be solved in a method for selecting a distribution network dominant demand response mode according to an exemplary embodiment. DETAILED DESCRIPTION

[0074] The following description and accompanying drawings fully illustrate the specific embodiments of this article so that those skilled in the art can practice them. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments of this article includes the entire scope of the claims, as well as all available equivalents of the claims. Herein, the terms "first", "second", etc. are only used to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the structure, device or equipment including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to such structure, device or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the structure, device or equipment including the elements. Each embodiment is described in a progressive manner herein, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other.

[0075] The terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. in this document indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this document and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of this document, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, it can also be the internal communication of two elements, it can be a direct connection, or it can be an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0076] As used herein, the term "plurality" means two or more than two, unless otherwise specified.

[0077] In this document, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0078] In this article, the term "and / or" is a description of the association relationship between objects, indicating that three relationships may exist. For example, A and / or B means: A or B, or, A and B.

[0079] It should be understood that, although the various steps in the flow chart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0080] Each module in the device or system of the present application can be implemented in whole or in part by software, hardware, or a combination thereof. The above modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above modules.

[0081] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0082] Figure 1 An embodiment of the method for selecting a distribution network dominant demand response mode of the present invention is shown.

[0083] In this optional embodiment, the distribution network-dominated demand response mode selection method includes:

[0084] Step S101, obtaining real-time operation monitoring data of the distribution network, obtaining the operation status of the distribution network according to the predefined trigger condition criteria of the distribution network operation trigger signal, and generating the division result of the demand response trigger signal event according to the event demand judgment criteria of the distribution network operation status;

[0085] Step S103, calculating the priority index of each type of demand response trigger signal event, obtaining a priority index evaluation value, and performing a priority evaluation on each type of demand response trigger signal event based on the priority index evaluation value;

[0086] Step S105, defining an evaluation criterion for the characteristic index based on the evaluation result, and scoring the characteristic index according to the evaluation criterion to obtain a characteristic index scoring result, and summing the characteristic index scoring results to obtain a comprehensive coefficient;

[0087] Step S107, calculate the weight coefficient of the characteristic index based on the comprehensive coefficient, and compare and judge the comprehensive value of the distribution network operation trigger signal according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network.

[0088] In this optional embodiment, the real-time operation monitoring data of the distribution network is obtained, the operation status of the distribution network is obtained according to the trigger condition criteria of the predefined distribution network operation trigger signal, and the division result of the demand response trigger signal event is generated according to the event demand judgment criteria of the distribution network operation status, including: obtaining the real-time operation monitoring data of the distribution network, extracting data information of various demand response trigger signal events from the real-time operation monitoring data of the distribution network, and obtaining the operation status of the distribution network according to the trigger condition criteria of the predefined distribution network operation trigger signal; based on the data information of various demand response trigger signal events, defining the judgment criteria of various demand response trigger signal events, and obtaining the trigger signals corresponding to various demand response trigger signal events; generating a distribution network node set based on the trigger signal, and realizing the division of the distribution network operation status based on the distribution network node set.

[0089] In this optional embodiment, the demand response trigger signal events include voltage exceeding the limit, network loss, grid frequency, line overload and peak shaving and valley filling; the characteristic indicators contained in the priority indicators include impact range indicator, duration indicator, change amplitude indicator, loss cost indicator and node access load indicator.

[0090] In this optional embodiment, the calculation formula of the priority index of the demand response trigger signal event is:

[0091] G i =ω1Z i +ω2T i +ω3C i +ω4A i +ω5B i i∈Q;

[0092] In the formula, G i is the priority index of the demand response trigger signal event occurring at node i; Z i is the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index; Q is the set of distribution network nodes with trigger signals.

[0093] In this optional embodiment, the evaluation criteria of the characteristic indicators are defined based on the evaluation results, and the characteristic indicators are scored according to the evaluation criteria to obtain the characteristic indicator scoring results, including: calculating the characteristic indicators contained in the priority indicators based on the evaluation results, and defining the evaluation criteria of the characteristic indicators based on the characteristic indicator calculation results; scoring the characteristic indicators based on the evaluation criteria of the characteristic indicators to obtain the characteristic indicator scoring results, so as to achieve standardization and unification of the characteristic indicators.

[0094] In this optional embodiment, the weight coefficient of the characteristic indicator is calculated based on the comprehensive coefficient, and the comprehensive value of the distribution network operation trigger signal is compared and judged according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network, including: calculating the weight coefficient of the characteristic indicator based on the evaluation criteria of the characteristic indicator and the comprehensive coefficient, and calculating the comprehensive value of the trigger signal corresponding to the demand response trigger signal event; comparing and judging the comprehensive values ​​of the trigger signal, selecting the demand response trigger signal event corresponding to the largest comprehensive value of the trigger signal as the distribution network operation event to be solved in the preset time period, so as to clarify the dominant demand response mode of the distribution network.

[0095] In this optional embodiment, the calculation formula of the weight coefficient of the characteristic index is:

[0096]

[0097] In the formula, S i Represents the comprehensive coefficient of characteristic indicators; Z i is the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index respectively.

[0098] Figure 2 An embodiment of the distribution network-dominated demand response mode selection system of the present invention is shown.

[0099] In this optional embodiment, the distribution network leading demand response mode selection system includes:

[0100] The trigger signal judgment and event classification module 201 is used to obtain the real-time operation monitoring data of the distribution network, obtain the distribution network operation state according to the predefined distribution network operation trigger signal trigger condition criteria, and generate the division result of the demand response trigger signal event according to the event demand judgment criteria of the distribution network operation state;

[0101] The trigger signal priority evaluation module 203 is used to calculate the priority index of each type of demand response trigger signal event, obtain the priority index evaluation value, and perform priority evaluation on each type of demand response trigger signal event based on the priority index evaluation value;

[0102] The priority index scoring calculation module 205 is used to define the evaluation criteria of the characteristic index based on the evaluation results, and score the characteristic index according to the evaluation criteria to obtain the characteristic index scoring results, and sum the characteristic index scoring results to obtain the comprehensive coefficient;

[0103] The indicator weight coefficient calculation module 207 is used to calculate the weight coefficient of the characteristic indicator based on the comprehensive coefficient, and compare and judge the comprehensive value of the distribution network operation trigger signal according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network.

[0104] In this optional embodiment, the trigger signal judgment and event division module 201 includes a trigger signal definition module (not shown in the figure), a trigger signal generation module (not shown in the figure) and a trigger signal event division module (not shown in the figure), wherein the trigger signal definition module is used to obtain real-time operation monitoring data of the distribution network, extract data information of various demand response trigger signal events from the real-time operation monitoring data of the distribution network, and obtain the distribution network operation status according to the predefined distribution network operation trigger signal trigger condition criteria; the trigger signal generation module is used to define the judgment criteria of various demand response trigger signal events based on the data information of various demand response trigger signal events, and obtain the trigger signals corresponding to various demand response trigger signal events; the trigger signal event division module is used to generate a distribution network node set based on the trigger signal, and realize the division of the distribution network operation status based on the distribution network node set.

[0105] In this optional embodiment, the demand response trigger signal events include voltage exceeding the limit, network loss, grid frequency, line overload and peak shaving and valley filling; the characteristic indicators contained in the priority indicators include impact range indicator, duration indicator, change amplitude indicator, loss cost indicator and node access load indicator.

[0106] In this optional embodiment, the calculation formula of the priority index of the demand response trigger signal event is:

[0107] G i =ω1Zi +ω2T i +ω3C i +ω4A i +ω5B i i∈Q;

[0108] In the formula, G i is the priority index of the demand response trigger signal event occurring at node i; Z i is the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index; Q is the set of distribution network nodes with trigger signals.

[0109] In this optional embodiment, the priority indicator scoring calculation module 205 includes an evaluation criterion definition module (not shown in the figure) and a characteristic indicator scoring module (not shown in the figure), wherein the evaluation criterion definition module is used to calculate the characteristic indicators contained in the priority indicators based on the evaluation results, and define the evaluation criteria of the characteristic indicators based on the characteristic indicator calculation results; the characteristic indicator scoring module is used to score the characteristic indicators based on the evaluation criteria of the characteristic indicators, and obtain the characteristic indicator scoring results, so as to achieve standardization and unification of the characteristic indicators.

[0110] In this optional embodiment, the indicator weight coefficient calculation module 207 includes a comprehensive value calculation module (not shown in the figure) and a demand response mode clarification module (not shown in the figure), wherein the comprehensive value calculation module is used to calculate the weight coefficient of the characteristic indicator based on the evaluation criteria and comprehensive coefficient of the characteristic indicator, and calculate the comprehensive value of the trigger signal corresponding to the demand response trigger signal event; the demand response mode clarification module is used to compare and judge the comprehensive value of the trigger signal, and select the demand response trigger signal event corresponding to the largest trigger signal comprehensive value as the distribution network operation event to be resolved in the preset time period, so as to clarify the dominant demand response mode of the distribution network.

[0111] In this optional embodiment, the calculation formula of the weight coefficient of the characteristic index is:

[0112]

[0113] In the formula, S i Represents the comprehensive coefficient of characteristic indicators; Z iis the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index respectively.

[0114] The method for selecting the dominant demand response mode of the distribution network provided by the present invention is described in detail below.

[0115] like Figure 4 As shown in the figure, the distribution network dominant demand response mode selection method includes:

[0116] The acquired real-time operation monitoring data of the distribution network is analyzed and calculated, and the operation status of the distribution network nodes (equivalent to the real-time operation voltage, network loss, current, etc. of the distribution network) is obtained according to the triggering condition criteria of the distribution network operation trigger signal. At the same time, according to the various events of the distribution network operation (equivalent to the demand response trigger signal event) demand judgment criteria, such as Figure 5 As shown, the classification results of five types of events are obtained: voltage over-limit, network loss, grid frequency, line overload, and peak shaving and valley filling.

[0117] A trigger signal judgment of the voltage over-limit event is performed based on the data information related to the voltage over-limit event in the acquired time period.

[0118] The judgment criteria for the voltage over-limit event triggering signal D1 are:

[0119]

[0120] Where: V i is the monitored voltage value of node i; V min is the lower limit of the node voltage set; V max The upper limit of the node voltage is set.

[0121] The trigger signal of the network loss event is determined based on the data information related to the network loss event in the acquired time period.

[0122] The judgment criteria for the network loss event triggering signal D2 are:

[0123]

[0124] Where: P ij,loss is the network power loss value on the line between node i and node j; P th,loss The upper limit of the line network loss is set.

[0125] The trigger signal of the power grid frequency event is determined based on the data information related to the power grid frequency event in the acquired time period.

[0126] The judgment criteria for the power grid frequency event trigger signal D3 are:

[0127]

[0128] Where: f is the monitoring frequency value of the system; f min is the lower limit of the system frequency; f max The upper limit of the system frequency is set.

[0129] A trigger signal judgment of the line overload event is performed based on the data information related to the line overload event in the acquired time period.

[0130] The judgment criteria for the line overload event triggering signal D4 are:

[0131]

[0132] Where: I ij is the monitored current value on the line between node i and node j; I th It is the set line current safety threshold, which is generally the line rated current.

[0133] According to the data information related to the peak shaving and valley filling event in the acquired time period, a trigger signal judgment of the peak shaving and valley filling event is performed.

[0134] The judgment criteria for the peak shaving and valley filling event triggering signal D5 are:

[0135]

[0136] Where: P i is the actual load of node i; P i,base is the benchmark load of node i; P th The threshold for the difference between the two is set.

[0137] Through the judgment criteria of various event requirements in the above distribution network operation, the corresponding trigger signal is obtained to divide the operation status of the distribution network nodes. The expression is as follows:

[0138]

[0139] Where: Q is the set of distribution network nodes with trigger signals; N is the set of distribution network nodes without trigger signals.

[0140] The priority index of the trigger signal nodes of various events in the regional distribution network is calculated to obtain the priority index evaluation values ​​of the trigger signal nodes of various events.

[0141] Considering that the impact scope, duration, change range, loss cost and characteristics of the occurrence nodes of the five types of events, such as voltage over-limit, network loss, grid frequency, line overload, and peak shaving and valley filling, are different, Figure 6 As shown, the trigger signals of various events are evaluated in priority according to these characteristic indicators.

[0142] The above priority index G i The calculation method is:

[0143] G i =ω1Z i +ω2T i +ω3C i +ω4A i +ω5B i i∈Q;

[0144] Where: G i is the priority index of the demand response trigger signal event occurring at node i; Z i is the impact range of the demand response trigger signal event occurring at node i; T i is the duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index. The larger the value, the greater the impact of the corresponding index. Figure 7 As shown, and satisfies ω1+ω2+ω3+ω4+ω5=1.

[0145] A unified standard is established for the impact range, duration, change range, loss cost and characteristics of the occurrence node contained in the calculated priority indicators, and the evaluation criteria for each indicator are obtained to score the impact range indicators within the priority indicators to achieve standardization and unification.

[0146] Calculate the impact range index:

[0147]

[0148] Where: Z i is the impact range indicator, N affected,i is the number of affected devices or users, N total,iThe total number of devices or users in the area.

[0149] The evaluation criteria for the impact range index are as follows, where z1, z2, and z3 are the judgment thresholds of the index, which are determined by the management and control personnel based on the power grid operation requirements:

[0150]

[0151] Score the duration indicators within the priority indicators to achieve standardization and unification.

[0152] Calculations for duration metrics:

[0153] T i =t end -t start ;

[0154] Where: T i is the duration indicator; t end is the time when the event ends, N total,i The time when the event occurred.

[0155] The evaluation criteria for the duration indicator are as follows, where t1, t2, and t3 are the judgment thresholds of the indicator, which are determined by the management and control personnel based on the power grid operation requirements:

[0156]

[0157] The importance index of node access load within the priority index is scored to achieve its standardization and unification.

[0158] Calculate the importance index of node access load:

[0159]

[0160] Where: C i is the importance index of node access load; P vital,i is the important load connected to node i, P total,i is the total load of the i-node access.

[0161] The evaluation criteria for the importance index of node access load are as follows, where c1, c2, and c3 are the judgment thresholds of the index, which are determined by the management and control personnel based on the power grid operation requirements:

[0162]

[0163] Score the change range indicators within the priority indicators to achieve their standardization and unification.

[0164] Calculate the change range indicator:

[0165]

[0166] Where: A i is the change range indicator, V i,t,max 、V i,t,min are the maximum and minimum values ​​of the monitored voltage at node i during period t, respectively. ij,loss,t,max , P ij,loss,t,min are the maximum and minimum network power loss between nodes i and j in period t, respectively. i,t,max 、f i,t,min are the maximum and minimum values ​​of the system monitoring frequency at node i during period t, respectively. ij,t,max ,I ij,t,min are the maximum and minimum values ​​of the monitored current between nodes i and j in period t, respectively. i,t,max , P i,t,min are the maximum and minimum access load of node i in period t, respectively.

[0167] The evaluation criteria for the change range index are as follows, where a1, a2, and a3 are the judgment thresholds of the index, which are determined by the management and control personnel based on the power grid operation requirements:

[0168]

[0169] Score the loss cost indicators within the priority indicators to achieve their standardization and unification.

[0170] The evaluation criteria for the loss cost index are as follows, where b1, b2, and b3 are the judgment thresholds of the index, which are determined by the management and control personnel based on the power grid operation requirements:

[0171]

[0172] The weight coefficient values ​​of the impact range, duration, change range, loss cost and the characteristics of the occurrence node itself are calculated to obtain the weight coefficient corresponding to each indicator.

[0173] First, the scoring results of the five indicators are added together to obtain the comprehensive coefficient S i :

[0174] S i =Z i +T i +C i +A i +B i ;

[0175] The weight coefficients corresponding to each indicator are calculated as follows:

[0176]

[0177] Compare and judge the obtained comprehensive values ​​of the corresponding event trigger signals, and according to the trigger signal priority index of each event at different nodes obtained by the above calculation, obtain the distribution network operation events to be solved in the final period. "Evaluation criteria" refers to the criteria for calculating each part of the priority index; and the "evaluation principle" here refers to an evaluation principle for comparing the priority comprehensive values.

[0178] When multiple events occur with a valid trigger signal, only one event can be responded to and processed in the current period. The calculation of the comprehensive values ​​d1, d2, d3, d4, and d5 of the trigger signals of various events is as follows:

[0179]

[0180] Where: d1, d2, d3, d4, and d5 correspond to the comprehensive values ​​of trigger signals under voltage over-limit, network loss, grid frequency, line overload, and peak shaving and valley filling events, respectively; Q is the set of distribution network nodes with trigger signals; D1 is the trigger signal of voltage over-limit event, D2 is the trigger signal of network loss event, D3 is the trigger signal of grid frequency event, D4 is the trigger signal of line overload event, and D5 is the trigger signal of peak shaving and valley filling event.

[0181] The event corresponding to the calculated maximum event trigger signal comprehensive value is selected as the distribution network operation event to be solved in this period, such as Figure 8 As shown, that is:

[0182] max{d1,d2,d3,d4,d5};

[0183] Wherein: d1, d2, d3, d4, and d5 correspond to the comprehensive values ​​of trigger signals under voltage over-limit, network loss, grid frequency, line overload, and peak shaving and valley filling events, respectively.

[0184] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 3 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store static information and dynamic information data. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps in the above method embodiment are implemented.

[0185] Those skilled in the art will understand that Figure 3 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present invention, and does not constitute a limitation on the computer device to which the solution of the present invention is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0186] In addition, the present invention also provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiment when executing the computer program.

[0187] In addition, the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiment are implemented.

[0188] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0189] The present invention is not limited to the structures which have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for selecting a dominant demand response mode in a distribution network, characterized in that: The method includes: Acquire the real-time operation monitoring data of the distribution network, obtain the distribution network operation status according to the predefined trigger condition criteria of the distribution network operation trigger signal, and generate the division result of the demand response trigger signal event according to the event demand judgment criteria of the distribution network operation status; Calculate the priority index of each type of demand response trigger signal event, obtain the priority index evaluation value, and perform priority evaluation on each type of demand response trigger signal event based on the priority index evaluation value; Based on the evaluation results, the evaluation criteria of the characteristic indicators are defined, and the characteristic indicators are scored according to the evaluation criteria to obtain the characteristic indicator scoring results, and the characteristic indicator scoring results are summed to obtain the comprehensive coefficient; The weight coefficient of the characteristic index is calculated based on the comprehensive coefficient, and the comprehensive value of the distribution network operation trigger signal is compared and judged according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network.

2. The method for selecting a distribution network dominant demand response mode according to claim 1, characterized in that: The real-time operation monitoring data of the distribution network is obtained, the operation status of the distribution network is obtained according to the trigger condition criteria of the predefined distribution network operation trigger signal, and the division result of the demand response trigger signal event is generated according to the event demand judgment criteria of the distribution network operation status, including: Acquire the real-time operation monitoring data of the distribution network, extract the data information of various demand response trigger signal events from the real-time operation monitoring data of the distribution network, and obtain the operation status of the distribution network according to the trigger condition criteria of the predefined distribution network operation trigger signal; Based on the data information of various demand response trigger signal events, the judgment criteria of various demand response trigger signal events are defined to obtain the trigger signals corresponding to various demand response trigger signal events; A distribution network node set is generated based on the trigger signal, and the distribution network operation status is divided based on the distribution network node set.

3. The method for selecting a distribution network dominant demand response mode according to claim 2, characterized in that: The demand response trigger signal events include voltage over-limit, network loss, grid frequency, line overload and peak-shaving; The characteristic indicators contained in the priority indicator include an impact range indicator, a duration indicator, a change amplitude indicator, a loss cost indicator and a node access load indicator.

4. The method for selecting a distribution network dominant demand response mode according to claim 3, characterized in that: The calculation formula of the priority index of the demand response trigger signal event is: G i =ω1Z i +ω2T i +ω3C i +ω4A i +ω5B i i∈Q; In the formula, G i is the priority index of the demand response trigger signal event occurring at node i; Z i is the impact range of the demand response trigger signal event occurring at node i; T i The duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index; Q is the set of distribution network nodes with trigger signals.

5. The method for selecting a distribution network dominant demand response mode according to claim 4, characterized in that: The evaluation criteria of the characteristic indicators are defined based on the evaluation results, and the characteristic indicators are scored according to the evaluation criteria. The characteristic indicator scoring results obtained include: Calculate the characteristic indicators contained in the priority indicators based on the evaluation results, and define the evaluation criteria of the characteristic indicators based on the characteristic indicator calculation results; The characteristic indicators are scored based on the evaluation criteria of the characteristic indicators to obtain the characteristic indicator scoring results, so as to achieve the standardization and unification of the characteristic indicators.

6. The method for selecting the dominant demand response mode of the distribution network according to claim 5, characterized in that: The weight coefficient of the characteristic index is calculated based on the comprehensive coefficient, and the comprehensive value of the distribution network operation trigger signal is compared and judged according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network, including: Calculate the weight coefficient of the characteristic indicator based on the evaluation criteria and comprehensive coefficient of the characteristic indicator, and calculate the comprehensive value of the trigger signal corresponding to the demand response trigger signal event; The comprehensive values ​​of the trigger signals are compared and judged, and the demand response trigger signal event corresponding to the largest comprehensive value of the trigger signal is selected as the distribution network operation event to be resolved in the preset time period to clarify the dominant demand response mode of the distribution network.

7. The method for selecting a distribution network dominant demand response mode according to claim 6, characterized in that: The calculation formula of the weight coefficient of the characteristic index is: In the formula, S i Represents the comprehensive coefficient of characteristic indicators; Z i is the impact range of the demand response trigger signal event occurring at node i; T i The duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index respectively.

8. A distribution network dominant demand response mode selection system, characterized in that: The system includes: The trigger signal judgment and event classification module is used to obtain the real-time operation monitoring data of the distribution network, obtain the distribution network operation status according to the predefined distribution network operation trigger signal trigger condition criteria, and generate the division result of the demand response trigger signal event according to the event demand judgment criteria of the distribution network operation status; A trigger signal priority evaluation module is used to calculate the priority index of various demand response trigger signal events, obtain the priority index evaluation value, and perform priority evaluation on various demand response trigger signal events based on the priority index evaluation value; The priority indicator scoring calculation module is used to define the evaluation criteria of the characteristic indicators based on the evaluation results, and score the characteristic indicators according to the evaluation criteria to obtain the characteristic indicator scoring results, and sum the characteristic indicator scoring results to obtain the comprehensive coefficient; The indicator weight coefficient calculation module is used to calculate the weight coefficient of the characteristic indicator based on the comprehensive coefficient, and compare and judge the comprehensive value of the distribution network operation trigger signal according to the weight coefficient to obtain the distribution network operation event to be solved, so as to clarify the dominant demand response mode of the distribution network.

9. The distribution network dominant demand response mode selection system according to claim 8, characterized in that: The trigger signal judgment and event division module includes a trigger signal definition module, a trigger signal generation module and a trigger signal event division module, wherein: The trigger signal definition module is used to obtain the real-time operation monitoring data of the distribution network, extract the data information of various demand response trigger signal events from the real-time operation monitoring data of the distribution network, and obtain the distribution network operation status according to the predefined trigger condition criteria of the distribution network operation trigger signal; A trigger signal generation module is used to define the judgment criteria of various demand response trigger signal events based on the data information of various demand response trigger signal events, and obtain the trigger signals corresponding to various demand response trigger signal events; The trigger signal event division module is used to generate a distribution network node set based on the trigger signal, and to realize the division of the distribution network operation status based on the distribution network node set.

10. The distribution network dominant demand response mode selection system according to claim 9, characterized in that: The demand response trigger signal events include voltage over-limit, network loss, grid frequency, line overload and peak-shaving; The characteristic indicators contained in the priority indicator include an impact range indicator, a duration indicator, a change amplitude indicator, a loss cost indicator and a node access load indicator.

11. The distribution network dominant demand response mode selection system according to claim 10, characterized in that: The calculation formula of the priority index of the demand response trigger signal event is: G i =ω1Z i +ω2T i +ω3C i +ω4A i +ω5B i i∈Q; In the formula, G i is the priority index of the demand response trigger signal event occurring at node i; Z i is the impact range of the demand response trigger signal event occurring at node i; T i The duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index; Q is the set of distribution network nodes with trigger signals.

12. The distribution network dominant demand response mode selection system according to claim 11, characterized in that: The priority index scoring calculation module includes an evaluation criteria definition module and a feature index scoring module, wherein: An evaluation criteria definition module is used to calculate the characteristic indicators contained in the priority indicators based on the evaluation results, and define the evaluation criteria of the characteristic indicators based on the characteristic indicator calculation results; The feature indicator scoring module is used to score the feature indicators based on the feature indicator evaluation criteria and obtain the feature indicator scoring results to achieve standardization and unification of the feature indicators.

13. The distribution network dominant demand response mode selection system according to claim 12, characterized in that: The indicator weight coefficient calculation module includes a comprehensive value calculation module and a demand response mode clarification module, wherein: A comprehensive value calculation module, used to calculate the weight coefficient of the characteristic indicator based on the evaluation criteria and comprehensive coefficient of the characteristic indicator, and calculate the comprehensive value of the trigger signal corresponding to the demand response trigger signal event; The demand response mode clarification module is used to compare and judge the comprehensive value of the trigger signal, select the demand response trigger signal event corresponding to the largest comprehensive value of the trigger signal as the distribution network operation event to be resolved in the preset time period, so as to clarify the dominant demand response mode of the distribution network.

14. The distribution network dominant demand response mode selection system according to claim 13, characterized in that: The calculation formula of the weight coefficient of the characteristic index is: In the formula, S i Represents the comprehensive coefficient of characteristic indicators; Z i is the impact range of the demand response trigger signal event occurring at node i; T i The duration of the demand response trigger signal event occurring at node i; C i A is the importance of node i access load; i B is the change amplitude of the demand response trigger signal event occurring at node i; i is the loss cost of the demand response trigger signal event occurring at node i; ω1, ω2, ω3, ω4 and ω5 are the weight coefficients corresponding to each characteristic index respectively.

15. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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