Control methods and systems for central air conditioning loads participating in demand response of power distribution networks

Abstract

This invention discloses a control method and system for central air conditioning load participation in distribution network demand response, belonging to the field of power grid voltage control. A control model for central air conditioning load participation in distribution network demand response and a time-varying room temperature equation are established. First, the control model is solved to obtain the central air conditioning load reduction at each node in the distribution network while ensuring voltage safety. Then, considering the air conditioning load reduction, user comfort requirements, voltage safety, and network active power loss requirements, the time-varying room temperature equation is solved to obtain the cooling start-up and shutdown times of the central air conditioning at each node in the distribution network. Based on this, a central air conditioning scheduling strategy is formulated to regulate the central air conditioning load. This invention effectively reduces the central air conditioning load while ensuring user comfort, compensating for undervoltage at the feeder end and reducing network active power loss, thereby improving the reliability and stability of the power system.

Description

Technical Field

[0001] This invention relates to the field of power grid voltage control, and in particular to a control method and system for central air conditioning loads to participate in the demand response of distribution networks. Background Technology

[0002] Since 2000, China's cooling energy demand has grown rapidly at an average annual rate of 2.5%. In 2020, cooling demand accounted for 16% of China's peak demand, and even more than half on extremely hot days, causing short-lived but sharp peaks in electricity demand in the power distribution network. At the same time, air conditioning load is also an important component of the adjustable resource interaction of the power distribution network, possessing enormous potential for innovation and energy efficiency improvement. It is of great significance for effectively reducing peak grid load, guiding rational electricity consumption by residents, and improving grid stability. Due to rapid economic and social development and the continuous improvement of people's living standards, the production, sales, and ownership of air conditioners have all increased significantly. The year-on-year growth trend and huge growth potential of air conditioning load make it possible for air conditioning load to participate in grid demand response.

[0003] Voltage exceeding limits is a significant factor threatening the safe and stable operation of distribution networks. Because low-voltage distribution networks often have a radial topology, electrical energy flows unidirectionally from the distribution transformer to the user, causing the voltage to gradually decrease from the distribution busbar along the feeders. With increasing load, voltage drops significantly during evening peak hours, sometimes even exceeding the lower limit. Air conditioning load is a major contributing factor to undervoltage during peak summer hours.

[0004] To ensure the safe and stable operation of the power system and the safety of electricity consumption for users, voltage must be maintained within the standard range. Traditional grid-side regulation methods for voltage regulation include adjusting bus voltage through main transformer tap changes in substations and locally boosting voltage by altering power flow distribution through reactive power compensation devices. With the development of new power systems dominated by renewable energy sources, the power system has shifted from "source-following-load" to "source-load interaction." Demand-side resources, with their wide regulation range, fast response speed, and diverse control methods, have enormous potential in distribution network voltage regulation. Although many studies have addressed distribution network voltage management and control through demand-side resources such as electric vehicles and energy storage, these efforts primarily focus on solving overvoltage and reverse power flow problems caused by renewable energy integration. They do not adequately consider undervoltage problems caused by heavy nighttime loads, nor the impact of demand-side resource participation in voltage regulation on network active power losses. Therefore, future research needs to expand the use of new demand-side resources for grid interaction while simultaneously addressing the aforementioned optimization issues.

[0005] Therefore, air conditioning load has remarkable potential for innovation and energy efficiency improvement. Air conditioning load is characterized by a high proportion during peak hours and a response speed within minutes. If the central air conditioning load of public buildings is treated as a demand-side controllable resource and its participation in the power distribution network dispatch on a large scale can effectively achieve grid voltage control during peak electricity consumption periods in summer. Summary of the Invention

[0006] The purpose of this invention is to provide a control method and system for central air conditioning load to participate in the demand response of the power distribution network. This method can effectively reduce the central air conditioning load while ensuring user comfort, thereby compensating for undervoltage problems at the feeder end and reducing network active power loss, thus improving the reliability and stability of the power system.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] A control method for central air conditioning loads participating in demand response of a power distribution network includes:

[0009] Based on the power grid dispatch center's requirements for distribution network voltage and network active power loss, a central air conditioning load participation distribution network demand response control model is established with the optimization objective of minimizing air conditioning load reduction and network active power loss.

[0010] Establish the time-varying equation of room temperature for central air conditioning load;

[0011] Collect network data and load data of the power distribution network, user comfort requirements, central air conditioning load data, and outdoor environmental data of the location of the central air conditioning unit;

[0012] Based on the network data and load data of the distribution network, the central air conditioning load participation in the distribution network demand response control model is solved to obtain the central air conditioning load reduction amount of each node in the distribution network when voltage safety is satisfied.

[0013] Based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, the time-varying room temperature equation is solved to obtain the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network.

[0014] The central air conditioning scheduling strategy is determined based on the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the distribution network.

[0015] During periods when demand response is required, the central air conditioning load is regulated according to the aforementioned central air conditioning scheduling strategy.

[0016] A control system for central air conditioning load participating in demand response of a power distribution network includes:

[0017] The control model establishment module is used to establish a central air conditioning load participation distribution network demand response control model based on the power grid dispatch center's demand for distribution network voltage and network active power loss, with the optimization objective of minimizing the reduction of air conditioning load and network active power loss.

[0018] The room temperature time-varying equation establishment module is used to establish the room temperature time-varying equation for the central air conditioning load;

[0019] The data acquisition module is used to collect network data and load data of the power distribution network, user comfort requirements, central air conditioning load data, and outdoor environmental data of the location of the central air conditioning unit.

[0020] The load reduction calculation module is used to solve the central air conditioning load participation in the distribution network demand response control model based on the network data and load data of the distribution network, and obtain the central air conditioning load reduction of each node in the distribution network when voltage safety is satisfied.

[0021] The cooling time calculation module is used to solve the time-varying room temperature equation based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, to obtain the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network.

[0022] The scheduling strategy determination module is used to determine the central air conditioning scheduling strategy based on the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the distribution network.

[0023] The control module is used to control the central air conditioning load according to the central air conditioning scheduling strategy during the time period when demand response is required.

[0024] A control device for central air conditioning loads participating in demand response of a power distribution network, including a dispatch center;

[0025] The dispatch center is used to execute the aforementioned control method for central air conditioning load to participate in the distribution network demand response.

[0026] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0027] This invention discloses a control method and system for central air conditioning load participation in distribution network demand response. It establishes a control model for central air conditioning load participation in distribution network demand response and a time-varying room temperature equation. First, the control model is solved to obtain the central air conditioning load reduction at each node in the distribution network while ensuring voltage safety. Then, considering the load reduction, user comfort requirements, voltage safety, and network active power loss requirements, the time-varying room temperature equation is solved to obtain the cooling start-up and shutdown times of the central air conditioning at each node in the distribution network. Based on this, a central air conditioning scheduling strategy is formulated to regulate the central air conditioning load. This invention effectively reduces the central air conditioning load while ensuring user comfort, compensating for undervoltage problems at the feeder ends and reducing network active power loss, thereby improving the reliability and stability of the power system. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A flowchart of a control method for central air conditioning load participating in the demand response of a power distribution network, provided in Embodiment 1 of the present invention;

[0030] Figure 2 This is a control principle diagram of a control device for central air conditioning load participating in the demand response of a power distribution network, provided in Embodiment 3 of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] like Figure 1 As shown, this embodiment of the invention provides a control method for central air conditioning load to participate in the demand response of a power distribution network, including:

[0035] Step 1: Based on the power grid dispatch center's requirements for distribution network voltage and network active power loss, establish a central air conditioning load participation distribution network demand response control model with the optimization objective of minimizing air conditioning load reduction and network active power loss.

[0036] For example, the process of establishing a demand response control model for central air conditioning loads in the power distribution network is as follows:

[0037] Step 1.1: Determine the time period during which a demand response is required.

[0038] Step 1.2: Based on the requirements of the scheduling center in Step 1.1, establish the objective function of the model as shown in equations (1)-(2):

[0039]

[0040]

[0041] Among them, P deair,j R represents the reduction in active power of air conditioning at node j, N represents the set of all nodes in the distribution network, and R represents the reduction in active power of air conditioning at node j. ij P represents the resistance value of the line between node i and node j. ij Q ij V represents the active and reactive power flowing from node i to node j, respectively. i Let i be the voltage magnitude at node i, and i→j represent the relationship between nodes.

[0042] By assigning weights to the two objectives and then adding them together, the multi-objective optimization problem is transformed into a single-objective optimization problem.

[0043]

[0044] Among them, M dis M is the scheduling weight for the reduction of active power load in air conditioning. loss The weight for network active power loss.

[0045] The constraints include power flow constraints, node voltage constraints, user comfort constraints, and central air conditioning load constraints.

[0046] The power flow constraints of the distribution network are shown in equation (4):

[0047]

[0048] in:

[0049]

[0050]

[0051] The power flow equation is the DistFlow model, where Rij X ij V represents the resistance and reactance of the line between node i and node j, respectively; i The voltage amplitude at node i; Equation (5) represents the net load active power P. j and net load reactive power Q j The expression, P j Let Q be the net load active power of node j. j P represents the net reactive power of node j. L,j Let P be the active power of the load at node j. air,j Let P be the active power of the central air conditioning load at node j. deair,j Q represents the reduction in active power of the air conditioning at node j. L,j Let be the reactive power of the load at node j.

[0052] Because the constraint contains a nonlinear equality constraint (6), the DistFlow model is nonconvex and it is difficult to find a global optimal solution. The nonlinear equality constraint can be relaxed into an inequality constraint, as shown in equation (7):

[0053]

[0054] The DistFlow model is relaxed to a second-order cone programming model, which is a typical convex optimization problem and can be solved using a general solver.

[0055] The node voltage constraint is shown in equation (8):

[0056]

[0057] Where V0 is the voltage reference value; ε is the allowable deviation, determined according to the national standard GB / T12325—2008 "Power Quality—Power Supply Voltage Deviation".

[0058] User comfort constraints are shown in equation (9):

[0059] T min ≤T k,in ≤T max (9)

[0060] Where T k,in For the indoor temperature of building k with central air conditioning load, T min T max These are the minimum and maximum indoor temperatures required to meet user comfort requirements, respectively.

[0061] User thermal comfort is characterized by the Thermal Sensation Vote (TSV) index. The relationship between the TSV value and indoor temperature is shown in Equation (10):

[0062] TSV = 0.24T in -5.37 (10)

[0063] Taking into account factors such as region, economic conditions, and energy-saving requirements, the scope of TSV is determined according to the provisions of Chinese National Standard GB 50736-2012 "Code for Design of Heating, Ventilation and Air Conditioning of Civil Buildings", thereby obtaining T min T max .

[0064] Establish central air conditioning load constraints and determine the model and method for central air conditioning load participation in the distribution network demand response control:

[0065] The air conditioning load constraint is shown in equation (11).

[0066]

[0067] In the formula, t on,j Let t be the cooling time of the floor where the central air conditioning system at node j participates in the scheduling. off,j N represents the downtime of the floors where the central air conditioning system at node j participates in the scheduling. j Let n be the total number of floors in the central air conditioning system at node j. j Let j be the number of floors on which the central air conditioning system starts and stops each time.

[0068] Step 2: Establish the time-varying equation for room temperature of the central air conditioning load.

[0069] The time-varying equation for room temperature under central air conditioning load is shown in equation (12):

[0070]

[0071] In the formula The real-time indoor temperature during the period when the central air conditioning at node j stops cooling. The real-time indoor temperature during the central air conditioning cooling period at node j. The initial temperature at which the central air conditioning unit at node j stops cooling. Let P be the initial temperature at which the central air conditioning system at node j begins cooling. air,j -P deair,j A represents the rated power of the central air conditioning unit at node j; j B j ,X j The time-varying coefficient of room temperature for the central air conditioning system at node j is determined by both building parameters and air conditioning parameters.

[0072]

[0073] In the formula:

[0074] T QCalculate the temperature for the hourly cooling load of the exterior walls and roof, t q To adjust parameters for other cities, T C The temperature for calculating the hourly cooling load of heat transfer through exterior windows in a typical city is T. out Outdoor temperature For the fresh air volume of the central air conditioning system at node j, α j β j γ j These are the first, second, and third intermediate variables, respectively.

[0075] C a V is the specific heat of air at constant pressure. j Let ρ be the cooling space volume of the central air conditioning unit at node j. a air density, Let S be the area of ​​the inner wall of node j. j Let j be the heat storage coefficient of the inner wall surface at node j;

[0076] Let J be the area of ​​the exterior walls and roof of the central air conditioning unit at node j. Let be the heat transfer coefficient of the exterior wall and roof at node j;

[0077] Let J be the area of ​​the exterior windows of the central air conditioning unit at node j. Let J be the heat transfer coefficient of the glass window at node j. is the correction factor for node j, and I is the number of exterior facades of the building where the central air conditioning load is located;

[0078] The cooling load is generated by the solar heat gain entering the room through the glass windows. The cooling load generated by heat dissipation from office and electronic equipment The cooling load generated by lighting heat dissipation The cooling load generated by heat dissipation from the human body;

[0079] This represents the maximum total solar irradiance. Let be the correction factor for the window glass of the central air conditioning unit at node j. The cooling load coefficient of the window glass;

[0080] Let ρ be the area of ​​the central air conditioning zone at node j. j,e C represents the power density of electrical equipment. LQ-e The sensible heat dissipation cooling load coefficient of equipment and appliances;

[0081] ρ j,l For lighting power density, C LQ-l Lighting heat dissipation cooling load coefficient;

[0082] q sFor the sensible heat loss of an adult male, q l For latent heat loss in adult males, C LQ-p ρ is the coefficient of sensible heat dissipation and cooling load of the human body. R Φ represents the population density and the clustering coefficient.

[0083] Step 3: Collect network data and load data of the power distribution network, user comfort requirements, central air conditioning load data, and outdoor environmental data of the location of the central air conditioning unit.

[0084] Network data for the distribution network includes: line impedance, topology, and node type. Load data for the distribution network represents the active and reactive power demand over a given day. User comfort requirements are the highest and lowest indoor temperatures that meet user comfort needs. Central air conditioning load data includes: node location, rated cooling capacity, building parameters of the building where the central air conditioning is located, population density, lighting power, and electrical equipment power. Outdoor environmental data includes: hourly calculated temperatures for cooling load on exterior walls and roofs, and hourly calculated temperatures for cooling load through window heat transfer.

[0085] Step 4: Based on the network data and load data of the distribution network, solve the central air conditioning load participation distribution network demand response control model to obtain the central air conditioning load reduction amount of each node in the distribution network when voltage safety is satisfied.

[0086] Based on the network data and load data of the distribution network, and according to equations (3), (4), (5), (7), (8), (9), (10) and (11), determine the central air conditioning load reduction of each node in the distribution network when voltage safety is met.

[0087] Step 5: Based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, solve the time-varying room temperature equation to obtain the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network.

[0088] The specific implementation steps are as follows:

[0089] Step 5.1: According to the time-varying equation for room temperature, under the condition that... The expression for the cooling start-up time and cooling shutdown time of the central air conditioning system within a control cycle is as follows:

[0090]

[0091] In the formula, t on,j t off,j These are the cooling start-up time and cooling shutdown time of the central air conditioning system within a control cycle.

[0092] Step 5.2: Based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, use the time-varying room temperature equation, the expression for the central air conditioning shutdown time and cooling time within a control cycle, and the user comfort constraints to determine the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network.

[0093] That is, using the load reduction amount obtained in step 4, the cooling and shutdown time t of the central air conditioning user k at node j is determined according to equations (12), (14), and (9). on,j t off,j .

[0094] Step 6: Determine the central air conditioning scheduling strategy based on the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the distribution network.

[0095] The central air conditioning load is regulated by the dispatch center. The regulation strategy is as follows: Since the central air conditioning cannot be frequently started and stopped, it is assumed that the cooling capacity of the central air conditioning chiller is evenly distributed across all floors. When the load is reduced, the start and stop are controlled through the floor terminals. The terminal equipment is set according to the start time t. on,j The shutdown time is t. off,j The central air conditioning system operates on a rotating shutdown basis. When the number of floors is even, only N central air conditioning units participate in load reduction. j Cooling is carried out on the 2nd floor, t on,j After time and with another N j / 2 floor states are swapped; when the number of floors is odd, it can be agreed that one floor will not participate in the rotation stop, and the remaining N floors... j -1 Even-numbered floors will be turned off in rotation as the floor number becomes even, thus ensuring that the entire central air conditioning system always operates at (P) air,j -P deair,j ) power operation.

[0096] Step 7: During the time period when demand response is required, regulate the central air conditioning load according to the central air conditioning scheduling strategy.

[0097] The nodal voltage constraints and user comfort constraints in the constraints define the safe voltage range and indoor temperature, avoiding sacrificing user comfort for the sake of voltage safety. To ensure voltage safety, according to the solved scheduling strategy, the central air conditioning load is partially reduced during periods when demand response is required.

[0098] The present invention has the following effects:

[0099] (1) Establish the time-varying equation of room temperature of central air conditioning load, so as to effectively reduce the central air conditioning load to compensate for the undervoltage problem at the end of the feeder and reduce the active power loss of the network while ensuring user comfort, thereby improving the reliability and stability of the power system.

[0100] (2) Taking into account the reduction of air conditioning load, voltage safety and network active power loss requirements, a control method for central air conditioning load to participate in the demand response of distribution network is provided.

[0101] This method is general in its modeling approach, has no special application conditions, does not have any requirements for system parameters, and has a wide range of applications. It is applicable to air conditioning load reduction under different dispatch center requirements and distribution network parameters. In addition to the objective function and satisfactory solution selection method given in this invention, in engineering practice, the optimization objective can be adjusted according to the dispatch requirements given by the dispatch center, and the model can be modeled and solved according to the method of this invention.

[0102] Example 2

[0103] In order to execute the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, this embodiment of the invention provides a control system for central air conditioning load to participate in the demand response of the power distribution network, including:

[0104] The control model establishment module is used to establish a central air conditioning load participation distribution network demand response control model based on the power grid dispatch center's requirements for distribution network voltage and network active power loss, with the optimization objective of minimizing the reduction of air conditioning load and network active power loss.

[0105] The room temperature time-varying equation establishment module is used to establish the room temperature time-varying equation for the central air conditioning load.

[0106] The data acquisition module is used to collect network data and load data of the power distribution network, user comfort requirements, central air conditioning load data, and outdoor environmental data of the location of the central air conditioning unit.

[0107] The load reduction calculation module is used to solve the central air conditioning load participation in the distribution network demand response control model based on the network data and load data of the distribution network, and obtain the central air conditioning load reduction of each node in the distribution network when voltage safety is satisfied.

[0108] The cooling time calculation module is used to solve the time-varying room temperature equation based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, to obtain the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network.

[0109] The scheduling strategy determination module is used to determine the central air conditioning scheduling strategy based on the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the distribution network.

[0110] The control module is used to control the central air conditioning load according to the central air conditioning scheduling strategy during the time period when demand response is required.

[0111] The control system for central air conditioning load to participate in the demand response of the distribution network provided in this embodiment of the invention is similar in working principle and beneficial effect to the control method for central air conditioning load to participate in the demand response of the distribution network described in the above embodiments, so it will not be described in detail here. For details, please refer to the introduction of the above method embodiments.

[0112] Example 3

[0113] This invention provides a control device for central air conditioning loads to participate in the demand response of a power distribution network, such as... Figure 2 As shown, it includes a dispatch center. The dispatch center is used to execute the control method for central air conditioning load to participate in the distribution network demand response as described in Embodiment 1.

[0114] Compared with existing technologies, this invention fully utilizes the regulation capability of central air conditioning load, comprehensively considering the reduction amount of air conditioning load, voltage safety, and network active power loss requirements. It provides a control method for central air conditioning load to participate in distribution network demand response, thereby effectively reducing central air conditioning load to compensate for undervoltage problems at the feeder end and reducing network active power loss while ensuring user comfort, thus improving the reliability and stability of the power system. Furthermore, this invention optimizes network active power loss by combining the efficiency and stability of power production, making it more aligned with engineering realities and facilitating efficient control of demand-side resources by the dispatch center, further promoting the development of demand response.

[0115] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0116] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A control method for a central air conditioning load participating in demand response of a power distribution network, characterized in that, include: Based on the power grid dispatch center's requirements for distribution network voltage and network active power loss, a central air conditioning load participation in distribution network demand response control model is established with the optimization objectives of minimizing air conditioning load reduction and network active power loss. The objective function of the central air conditioning load participation in distribution network demand response control model is: In the formula, Let be the objective function. The scheduling weight for the reduction of active power load for air conditioning. Weights for network active power loss. Represents a node j The reduction in the active power of the air conditioner. Represents the set of all nodes in the distribution network. Represents a node i and nodes j The resistance value of the circuit. , They represent the nodes respectively i To the node j The outflow of active and reactive power, For nodes i voltage amplitude, Indicates the relationship between nodes; Establish the time-varying equation of room temperature for central air conditioning load; Collect network data and load data of the power distribution network, user comfort requirements, central air conditioning load data, and outdoor environmental data of the location of the central air conditioning unit; Based on the network data and load data of the distribution network, the central air conditioning load participation in the distribution network demand response control model is solved to obtain the central air conditioning load reduction amount of each node in the distribution network when voltage safety is satisfied. Based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, the time-varying room temperature equation is solved to obtain the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network. The central air conditioning scheduling strategy is determined based on the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the distribution network. During periods when demand response is required, the central air conditioning load is regulated according to the aforementioned central air conditioning scheduling strategy.

2. The control method of claim 1, wherein, The constraints of the central air conditioning load participating in the distribution network demand response control model include: distribution network power flow constraints, node voltage constraints, user comfort constraints, and air conditioning load constraints. The power flow constraints of the distribution network are: In the formula, , They are nodes i and nodes j The resistance and reactance of the circuit, For nodes j Net load active power, For nodes j Net load reactive power, , They represent the nodes respectively j To the node l The outflow of active and reactive power, For nodes j The voltage amplitude; , For nodes j The active power of the load, For nodes j The reactive power of the load; For nodes i and nodes j The impedance of the line, ; The node voltage constraint is In the formula, For the allowable deviation, This is the voltage reference value; The user comfort constraint is as follows: In the formula, For buildings with central air conditioning load k Indoor temperature, These are the minimum and maximum indoor temperatures required to meet user comfort requirements, respectively. The air conditioning load constraint is In the formula, For nodes j Cooling time for floors affected by central air conditioning system. For nodes j The downtime of the floors where the central air conditioning system is involved in the scheduling. For nodes j The total number of floors with central air conditioning. For nodes j The number of floors on which the central air conditioning system is turned on and off each time.

3. The control method for central air conditioning load participating in distribution network demand response according to claim 2, characterized in that, The time-varying equation for room temperature is: ； In the formula, For nodes j Real-time indoor temperature during periods when the central air conditioning system is not cooling. For nodes j Real-time indoor temperature during central air conditioning cooling period For nodes j The initial temperature at which the central air conditioning system stops cooling. For nodes j The initial temperature at which the central air conditioning system begins to cool. For nodes j The rated power of the central air conditioning system, They are nodes j The time-varying coefficients of the first, second, and third room temperatures of the central air conditioning system: ； Calculate the temperature for the hourly cooling load of the exterior walls and roof. Adjust parameters for other cities. Calculate the hourly cooling load for heat transfer through exterior windows in a typical city. Outdoor temperature For nodes j The fresh air volume of the central air conditioning system , , These are the first, second, and third intermediate variables, respectively. The specific heat of air at constant pressure. For nodes j The volume of the cooling space in a central air conditioning system. air density, For nodes j Interior wall area, For nodes j Heat storage coefficient of interior walls; For nodes j The area of ​​the exterior walls and roof of the central air conditioning unit. For nodes j Heat transfer coefficients of exterior walls and roofs; For nodes j The exterior window area of ​​the central air conditioning system For nodes j The heat transfer coefficient of glass windows, For nodes j Correction factor, I The number of building facades where the central air conditioning load is located; The cooling load is generated by the solar heat gain entering the room through the glass windows. The cooling load generated by heat dissipation from office and electronic equipment The cooling load generated by lighting heat dissipation The cooling load generated by heat dissipation from the human body; This represents the maximum total solar irradiance. For nodes j Correction factor for window glass in central air conditioning systems. The cooling load coefficient of the window glass; For nodes j The area of ​​the central air conditioning zone. For the power density of electrical equipment, The sensible heat dissipation cooling load coefficient of equipment and appliances; For lighting power density, Lighting heat dissipation cooling load coefficient; Sensible heat loss for an adult male. For latent heat loss in adult males, The coefficient of performance for sensible heat dissipation and cooling load of the human body. For personnel density, This represents the clustering coefficient.

4. The control method for central air conditioning load participating in distribution network demand response according to claim 1, characterized in that, The network data of the distribution network includes: line impedance, topology, and node type; The load data of the distribution network is the active and reactive power demand of the distribution network within a day; The user comfort requirements are the highest and lowest indoor temperatures that meet the user's comfort needs. The central air conditioning load data includes: the location of the node, the rated cooling power, the building parameters of the building where the central air conditioning is located, the population density in the building, the lighting power, and the power of electrical equipment; The outdoor environmental data includes: hourly values ​​of the hourly cooling load calculation temperature of the exterior walls and roof, hourly cooling load calculation temperature of the exterior window heat transfer, and hourly cooling load calculation temperature of the exterior window heat transfer.

5. The control method for central air conditioning load participating in distribution network demand response according to claim 3, characterized in that, Based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, the time-varying room temperature equation is solved to obtain the cooling start-up and cooling shutdown times of the central air conditioning at each node in the power distribution network, specifically including: According to the aforementioned time-varying equation for room temperature, when satisfying The expression for the cooling start-up time and cooling shutdown time of the central air conditioning system within a control cycle is as follows: ； ； In the formula, , These are the cooling start-up time and cooling shutdown time of the central air conditioning system within a control cycle; Based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network are determined using the time-varying room temperature equation, the expression for the central air conditioning shutdown time and cooling time within a control cycle, and the user comfort constraints.

6. The control method for central air conditioning load participating in distribution network demand response according to claim 5, characterized in that, The central air conditioning scheduling strategy includes: When the total number of floors for central air conditioning is even, only The central air conditioning system on each floor participates in load reduction for cooling. After time and another The floor status is swapped; When the total number of floors in the central air conditioning system is odd, one floor is pre-selected not to participate in the rotational shutdown, and the remaining floors... Even-numbered floors will rotate their operation based on the total number of floors covered by the central air conditioning system.

7. A control system for central air conditioning load participating in demand response of a power distribution network, characterized in that, include: The control model establishment module is used to establish a central air conditioning load participation in the distribution network demand response control model based on the power grid dispatch center's requirements for distribution network voltage and network active power loss, with the optimization objective of minimizing the reduction of air conditioning load and network active power loss. The objective function of the central air conditioning load participation in the distribution network demand response control model is: In the formula, Let be the objective function. The scheduling weight for the reduction of active power load for air conditioning. Weights for network active power loss. Represents a node j The reduction in the active power of the air conditioner. Represents the set of all nodes in the distribution network. Represents a node i and nodes j The resistance value of the circuit. , They represent the nodes respectively i To the node j The outflow of active and reactive power, For nodes i voltage amplitude, Indicates the relationship between nodes; The room temperature time-varying equation establishment module is used to establish the room temperature time-varying equation for the central air conditioning load; The data acquisition module is used to collect network data and load data of the power distribution network, user comfort requirements, central air conditioning load data, and outdoor environmental data of the location of the central air conditioning unit. The load reduction calculation module is used to solve the central air conditioning load participation in the distribution network demand response control model based on the network data and load data of the distribution network, and obtain the central air conditioning load reduction of each node in the distribution network when voltage safety is satisfied. The cooling time calculation module is used to solve the time-varying room temperature equation based on the central air conditioning load reduction, user comfort requirements, central air conditioning load data, and outdoor environmental data of the central air conditioning location, to obtain the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the power distribution network. The scheduling strategy determination module is used to determine the central air conditioning scheduling strategy based on the cooling start-up time and cooling shutdown time of the central air conditioning at each node in the distribution network. The control module is used to control the central air conditioning load according to the central air conditioning scheduling strategy during the time period when demand response is required.

8. A control device for central air conditioning load participating in demand response of a power distribution network, characterized in that, Including the dispatch center; The dispatch center is used to execute the control method for central air conditioning load to participate in the demand response of the distribution network as described in any one of claims 1 to 6.

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