Efficient Transfer and Power Supply Assurance Method for Substation Area Load Based on Hybrid V2G Facilities

Abstract

The present invention relates to the technical field of power system operation reliability and control, and particularly to a method for efficient transfer and power supply guarantee of substation area load based on hybrid V2G facilities. The method includes: determining the power outage range according to the number of power outage substations, and calculating the power outage load capacity; judging the power outage scenario according to the power outage range, and the substation area controller corresponding to the power outage substation determines the power outage situation by comparing the power outage load capacity with the power supply guarantee capacity, so as to determine the collaborative optimization allocation of the type, quantity and power supply guarantee capacity of the V2G facilities required for power supply guarantee, and finally transfer the power outage load of the substation area to the power supply guarantee branch of the V2G facilities; the hybrid V2G facilities participating in power supply guarantee supply power to the power outage branch at the same time, and the hybrid V2G facilities not participating in power supply guarantee maintain the original access, operation mode and functions. Compared with the prior art, the present invention has the advantages of simple and time-saving operation, avoiding excessive delay waiting, and being able to adapt to the power supply guarantee requirements of different power outage ranges, scenarios and power outage capacity situations.

Description

Technical Field

[0001] The present invention relates to the field of power system operation reliability and control technology, and in particular to a method for efficient power transfer and power protection of loads in an area based on a hybrid V2G facility. Background Art

[0002] During peak hours of electricity consumption, distribution network areas are prone to heavy or overload, and the power supply stability of some branches and loads is affected. When equipment or lines in the distribution system fail, the power supply of some loads will be forced to terminate. In order to ensure the continuous operation of basic living or production equipment in the area, some basic or important loads need to be transferred to new power sources in a timely manner to maintain continuous and uninterrupted operation, waiting for the power supply load to transition to a stable state or the distribution network system to return to normal.

[0003] If the switch operation is used to transfer the supply load to the adjacent distribution station area, the load rate of the adjacent distribution station area will increase significantly. If the backup power of the adjacent distribution station area is insufficient, it will easily cause the main transformer outgoing line in the station area to be overloaded or overloaded, making it difficult to achieve continuous and stable power supply guarantee. At the same time, the path and plan for the above load transfer need to be formulated by the power grid dispatching department, and the process will also increase the corresponding delay time.

[0004] If the guaranteed load is transferred to the emergency power supply (vehicle) facilities, the emergency power supply (vehicle) facilities still need to wait for the instructions of the grid dispatching department, drive to the target location, connect the temporary power supply to the distribution network port of the guaranteed supply, and finally start the power supply process. Therefore, the delay and waiting time of the guaranteed supply process are long, which is not conducive to shortening the power outage time of load transfer and reducing power outage losses.

[0005] Even if automatic power transfer paths and plans are set up for important loads in the distribution network system, it is still necessary to ensure that there is sufficient backup power in nearby distribution stations. Otherwise, there is still a possibility of power supply instability or even interruption during the load transfer process.

[0006] In summary, the current load transfer and power supply protection schemes in distribution network substations have multiple problems, such as the need to wait for instructions from the grid dispatching department, long delays in the startup process, and the need for nearby distribution substations to have sufficient backup power. These problems make it impossible to guarantee the timeliness, continuity, and reliability of load transfer.

[0007] How to achieve automatic and efficient transfer and power supply of substation loads has become a technical problem that needs to be solved. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a method for efficient power transfer and power protection of substation loads based on hybrid V2G facilities.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] According to one aspect of the present invention, a method for efficient load transfer and power protection in a substation based on a hybrid V2G facility is provided, wherein the hybrid V2G facility includes a fixed AC V2G facility, a fixed DC V2G facility, and a mobile V2G facility, and the method includes:

[0011] Step 1: Determine the power failure range according to the number of power failure areas, and further determine the power failure load capacity;

[0012] Step 2: Determine the power failure scenario based on the power failure scope, compare the power failure load capacity with the power protection capacity to determine the power failure situation, and thus determine the type and number of V2G facilities required for power protection and the coordinated optimization allocation of the power protection capacity;

[0013] Step 3: according to the result of step 2, the power-off load in the substation is transferred to the power-protection branch of the V2G facility;

[0014] Step 4: The hybrid V2G facilities participating in power supply protection provide power to the corresponding power-lost branches at the same time, and the hybrid V2G facilities not participating in power supply protection continue to maintain the original access, operation mode and functions.

[0015] Preferably, the types and quantities of V2G facilities required for power supply protection determined in step 2 are specifically:

[0016] ,

[0017] ,

[0018] in, n FA , n FD and n M They respectively represent the number of fixed DC V2G facilities, fixed AC V2G facilities and mobile V2G facilities allocated by the substation controller to participate in power supply protection; P FA,max , P FD,max and P M,max Respectively represent the maximum rated power of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities; N FA , N FD and N M They are the number of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities; PLoss is the power failure load capacity;

[0019] The selection priorities of the hybrid V2G facilities are set from high to low as fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities.

[0020] Preferably, judging the power failure scenario according to the power failure range of the substation area includes:

[0021] If the power outage covers part of a branch of a substation, and the substation is not a V2G facility or a public power supply substation, the power outage scenario is scenario 1;

[0022] If the power outage covers part of a branch of a substation, and the substation is a V2G facility and public power supply substation, the power outage scenario is scenario 2;

[0023] If the power outage covers the entire area of ​​1 transformer substation, the power outage scenario is scenario 3;

[0024] If the power outage covers multiple substations, and some branches of each substation lose power, and these substations are not V2G facilities or public power supply substations, the power outage scenario is scenario 4;

[0025] If the power outage covers multiple substations, some branches in each substation lose power, and one of the substations is a V2G facility and public power supply substation, the power outage scenario is scenario 5;

[0026] If the power outage covers multiple substations, all branches in each substation lose power, and these substations are not V2G facilities or public power supply substations, the power outage scenario is scenario 6;

[0027] If the power outage covers multiple substations, all branches in each substation lose power, and one of the substations is a V2G facility and public power supply substation, the power outage scenario is scenario 7;

[0028] If the power outage covers all substations and some branches in each substation lose power, the power outage scenario is scenario 8;

[0029] If the power outage covers all substations and all branches in each substation lose power, the power outage scenario is scenario 9.

[0030] Preferably, the power failure load capacity P Loss Compared with the power-saving capacity, the process of judging the power failure situation includes:

[0031] like P Loss ≤ P FA , it is judged as power failure situation 1;

[0032] like PFA < P Loss ≤ P FD , it is judged as power failure situation 2;

[0033] like P FD < P Loss ≤ P F , it is judged as power failure situation 3;

[0034] like P F < P Loss ≤ P V2G , it is judged as power failure situation 4;

[0035] like P V2G < P Loss , it is judged as power failure situation 5;

[0036] in P FA is the total power of fixed AC V2G facilities; P FD is the total power of fixed DC V2G facilities; P F is the total power of fixed V2G facilities, P F = P FA + P FD ; P V2G The total power of all V2G facilities is: P V2G = P F + P M , P M is the total power of mobile V2G facilities;

[0037] The total power of each V2G facility meets P FA <P FD <P F <P V2G .

[0038] More preferably, in the power outage situation 5, because the total V2G power protection capacity cannot meet the power outage load capacity, some important loads in the substation are selected for power protection, and some non-important loads are discarded.

[0039] Preferably, when the power outage covers more than one area, each area controller calculates the V2G power conservation capacity separately. P V2G Difference with power failure load capacity Δ P IM = P Loss - P V2G , and add up the total difference of each area to get Δ P IM,sum , and based on the total difference Δ P IM,sum According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS , in P GS = P Loss -Δ P IM,sum ;based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required to maintain power, and coordinate the optimal allocation of power maintenance capacity.

[0040] Preferably, the collaborative optimization allocation of the power conservation capacity includes: setting constraints on the V2G facilities, collaboratively optimizing the power allocation of different types of V2G facilities, and minimizing the comprehensive operating cost of the hybrid V2G facilities, specifically:

[0041] ,

[0042] in, P FA,t , P FD,t , P M,t and P T,t They represent the fixed AC V2G facilities, fixed DC V2G facilities, mobile V2G facilities and the load in the substation. t Real-time power at all times; C FA , C FD and C M They represent the operating costs of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities respectively;

[0043] SOC FA,t , SOC FD,t and SOC M,tRespectively represent the fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities in t The real-time state of charge SOC at the moment; the subscripts max and min represent the maximum and minimum values ​​of the real-time state of charge SOC respectively; TH Indicates the total time that V2G facilities participate in power supply protection.

[0044] Preferably, the process of transferring the power-off load in the substation area to the power-protection branch of the V2G facility includes:

[0045] Switch the power-protected V2G facilities to the switch contacts of the corresponding power-protected station area;

[0046] The power protection branch switch of the corresponding substation is closed;

[0047] The corresponding area load protection switch is closed, and the corresponding area load branch switch is opened;

[0048] The power-lost load in the substation is transferred to the power supply branch of the V2G facility.

[0049] More preferably, for power outage situation 5, when the power outage range does not involve V2G facilities and public power supply stations, the power protection branch switches of the V2G facilities and the public power supply stations are turned on.

[0050] More preferably, for power outage situation 5, the station controller calculates the V2G power conservation capacity P V2G Power failure load capacity P Loss The difference Δ P IM = P Loss - P V2G ; Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ,in P GS = P Loss -Δ P IM ;based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required to maintain power, and coordinate the optimal allocation of power maintenance capacity.

[0051] Preferably, when the power outage covers more than one area, each area controller calculates the V2G power conservation capacity separately. P V2G Difference with power failure load capacity Δ PIM = P Loss - P V2G , and add up the total difference of each area to get Δ P IM,sum , and based on the total difference Δ P IM，sum According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ,in P GS = P Loss -Δ P IM,sum ;based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required to maintain power, and coordinate the optimal allocation of power maintenance capacity.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] 1) The present invention uses hybrid V2G facilities of different types and powers as power supply for power protection, determines the power failure area and power failure scenario according to the power failure range, compares the power failure load capacity with the power protection capacity to judge the power failure situation, thereby determining the type and quantity allocation of V2G facilities required for power protection and the coordinated optimization allocation of protection capacity, setting up power protection branches that access and match different substations, transferring the power failure load of the substation to the power protection branch of the V2G facility, and automatically and efficiently meeting the power protection needs of different power failure load capacities in different substations through coordinated optimization combination, effectively ensuring the reliability of power supply in the substation and the continuous and stable operation of the basic life order.

[0054] 2) The present invention conveniently utilizes local V2G facilities as a power supply energy source. The mobile V2G facilities can move flexibly and autonomously, quickly reach the target and avoid the target moving. The service range is wide and is not restricted by geographical location. It effectively expands the limited service range of fixed V2G facilities. While ensuring load transfer and power supply, it also meets the temporary power needs of electric vehicles of a certain capacity and some power facilities in remote areas. It also sets priorities for different V2G facilities to avoid additional time delays caused by waiting for complex dispatching instructions, and efficiently realizes load transfer and power supply.

[0055] 3) Based on the load transfer circuit topology of the hybrid V2G facility, the present invention sets up comprehensive power failure scenarios and power failure situations, and provides targeted load transfer and power protection implementation processes for different scenarios and situations, fully adapting to different power failure scenarios and power failure situations, and improving the comprehensiveness and reliability of power protection.

[0056] 4) Under power outage situation 5, because the total V2G power protection capacity cannot meet the power outage load capacity, the present invention selects some important loads in the substation area for power protection and abandons some non-important loads, which effectively ensures the reliability of power supply in the substation area and the continuous and stable operation of basic life order, avoids life obstacles and economic losses caused by power supply terminals, and has significant economic and social benefits.

[0057] 5) The present invention utilizes the advantages of mobile V2G facilities, such as flexible and autonomous movement, quick arrival at the target and avoiding target movement, wide service range and no geographical restrictions, to effectively expand the limited service range of fixed V2G facilities. While ensuring load transfer and power supply, the present invention can also meet the temporary power needs of electric vehicles of a certain capacity and some power facilities in remote areas.

[0058] 6) The configuration and layout of the power supply branch based on the hybrid V2G facility of the present invention is simple and intuitive, requires few auxiliary facilities, has low construction and operation and maintenance costs, and has broad prospects for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A schematic diagram of a topological structure of a typical residential area power supply system in an embodiment of the present invention;

[0060] Figure 2 It is a flow chart of the technical method for load transfer and power protection in the substation area based on the hybrid V2G facility in the present invention;

[0061] Figure 3 It is a schematic diagram of the configuration of the substation controller in the topology of the power supply system in the present invention. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0063] The purpose of the present invention is to ensure the continuous operation of basic living or production equipment in the substation area, some basic or important loads need to be transferred to the new power supply in time to maintain continuous and uninterrupted operation, waiting for the power supply load to transition to a stable state or the distribution network system to return to normal, and realize automatic and efficient transfer and power supply protection of the substation area load based on the hybrid V2G facilities.

[0064] This embodiment relates to a method for efficient load transfer and power protection in a substation based on hybrid V2G facilities. A load transfer and power protection branch with V2G facilities as the power supply is designed for each substation. Different types of V2G facilities are converted to different distribution network substation branches through intelligent conversion switches as a joint power supply for emergency power protection. On the one hand, this solution makes full use of the local V2G power supply in the substation to drive load transfer and power protection. The transfer path and conversion operation are simple and time-saving. There is no need to wait for instructions from the power grid dispatching department, avoiding additional delays and power outages, and effectively improving the transfer efficiency. On the other hand, V2G power protection facilities of different powers and types are accurately matched according to the transfer load requirements of different substation branches, optimizing the allocation of transfer capacity and improving the utilization rate of power supply for power protection.

[0065] This embodiment designs a typical residential area power supply system topology including three power supply areas and corresponding load transfer and power protection branches, such as Figure 1 , and designed the control strategies for key processes and functions such as triggering, V2G facility quantity allocation and power coordinated optimization allocation in the load transfer and power protection technology controlled by the substation controller. According to the different power outage ranges of the substation, all possible typical power outage scenarios are set, and then the power outage load and power protection capacity are compared. Finally, the substation load transfer and power protection schemes and their main implementation steps for different scenarios and different power outage situations are designed. Finally, the complete flow chart of the implementation of the technical scheme is summarized for theoretical reference and application implementation.

[0066] like Figure 1 A typical residential power distribution system includes three distribution substations, among which substation 1 and substation 2 are used as living power supply substations for the residential unit buildings, and substation 3 is used as the V2G facility and public power supply substation.

[0067] The power load capacity of a unit building in the community is P L , if a certain area contains N L If there are 1 unit building, the load capacity of this area is P Z =N L · P L In this embodiment, a hybrid V2G (Vehicle to Grid) facility is used as a combined power source for load transfer and power protection in three distribution substations.

[0068] Hybrid V2G facilities are divided into fixed V2G facilities and mobile V2G facilities. Fixed V2G facilities are divided into fixed AC V2G facilities and fixed DC V2G facilities. The power of DC V2G facilities is usually greater than that of AC V2G facilities. Figure 1FA1-V2G and FA2-V2G in the field), fixed DC V2G facilities ( Figure 1 FD1-V2G and FD2-V2G in the Figure 1 The power of each unit of M1-V2G and M2-V2G is P FAi , P FDj , P Mk , ( i , j , k The configuration quantities of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities are respectively N FA , N FD and N M .

[0069] The total power of AC V2G facilities is: ;

[0070] The total power of a DC V2G facility is: ;

[0071] The total power of mobile V2G facilities is: .

[0072] In this embodiment, both area 1 and area 2 include N L = 6 unit building branches, then P Z1 = P Z2 =6 P L ,in P Z1 and P Z2 The total capacity of the area. P L Substation 3 includes public power loads such as distribution room, monitoring, garage, fire water pump, domestic water pump, etc. Substation 3 is equipped with 2 sets of fixed AC V2G facilities (FA1-V2G and FA2-V2G), 2 sets of fixed DC V2G facilities (FD1-V2G and FD2-V2G), and 2 sets of mobile V2G facilities (M1-V2G and M2-V2G).

[0073] The total power of a fixed AC V2G facility is: P FA = P FA1+ P FA2 ;

[0074] The total power of a fixed DC V2G facility is: P FD = P FD1 + P FD2 ;

[0075] The total power of a fixed V2G facility is: P F = P FA + P FD ;

[0076] The total power of mobile V2G facilities is: P M = P M1 + P M2 ;

[0077] The total power of all V2G facilities is: P V2G = P F + P M .

[0078] According to the above settings, there is the following relationship: P FA <P FD <P F <P V2G The rated power of fixed AC V2G facilities is lower than that of fixed DC V2G facilities. Mobile V2G facilities need to be used as flexible backup facilities to meet the temporary power needs of electric vehicles of a certain capacity and power facilities in remote locations.

[0079] according to Figure 1 The power distribution system topology design of the V2G facility is as follows: V2G facility → SA transfer switch (SA) of the V2G facility → electric energy meter → power branch switch (QS v )→Power-off load protection switch (QS) in the substation→Power-off load in the substation.

[0080] If the power supply area cannot continue to guarantee power supply or the power failure load capacity is lost during the peak power consumption or power supply system failure P Loss Expressed as P Loss =N Loss · P L ,P L is the power load capacity, N Loss is the number of de-energized branches.

[0081] According to the power outage range of different substations, all possible typical power outage scenarios are set, and then the power outage load and power protection capacity are compared, and finally the load transfer path and power protection plan corresponding to different power outage scenarios and different power outage conditions are determined.

[0082] In the process of load transfer and power protection, the selection priority of the V2G facility type is set from high to low as fixed AC V2G facilities, fixed DC V2G facilities, and mobile V2G facilities. The power failure scenarios are summarized in Table 1. The power failure scenarios of the comparison between the power failure load and the V2G power protection capacity are shown in Table 2.

[0083] Table 1

[0084] Power failure range Power failure scenario Power failure scenario description 1 station Scenario 1 One branch of Area 1 (or Area 2) loses power or several branches lose power at the same time 1 station Scenario 2 One of the public load branches in the substation 3 loses power or several public load branches lose power at the same time 1 station Scene 3 The main transformer or busbar in the substation is faulty or under maintenance, causing a total power outage in the substation 2 stations Scene 4 Several branches in Area 1 and Area 2 lose power at the same time 2 stations Scene 5 Several branches of Area 1 and Area 3 (or Area 2 and Area 3) lose power at the same time 2 stations Scene 6 The main transformer and busbar of area 1 and area 2 are faulty or under maintenance, causing the entire area to lose power. 2 stations Scene 7 The main transformer or busbar of Area 1 and Area 3 (or Area 2 and Area 3) is faulty or under maintenance, causing a total power outage in the area. 3 stations Scene 8 Several branches in Area 1, Area 2 and Area 3 lose power at the same time 3 stations Scene 9 The main transformer or busbar of Area 1, Area 2 and Area 3 is faulty or under maintenance, causing a total power outage in the area

[0085] Table 2

[0086] Power failure Judgment conditions Power failure situation 1 <![CDATA[ P Loss ≤ P FA ]]> Power failure 2 <![CDATA[ P FA < P Loss ≤ P FD ]]> Power failure situation 3 <![CDATA[ P FD < P Loss ≤ P F ]]> Power failure situation 4 <![CDATA[ P F < P Loss ≤ P V2G ]]> Power failure situation 5 <![CDATA[ P V2G < P Loss ]]>

[0087] All V2G facilities are powered by area 3. Therefore, in normal state, the transfer switches (SM) of all V2G facilities are connected to contact 3, and the power branch switch QS v 3 In closed state.

[0088] In case of power failure 5, due to the full V2G power conservation capacity P V2G Unable to meet power failure load capacity P Loss At this time, each area controller should select some important loads in the area to protect power supply, and abandon some non-important loads.

[0089] In case of power outage in the entire substation, or power outage in multiple branches of two or more substations, P Loss The scale of power outages is larger, and the probability of power outages with smaller numbers will become smaller.

[0090] Mobile V2G facilities have many advantages, such as flexible and autonomous movement, quick arrival at the target and avoiding target movement, wide service range and no geographical restrictions. They can effectively expand the limited service range of fixed V2G facilities, appropriately increase the number of mobile V2G facilities M according to the load scale and power supply demand of the substation, and expand the spare capacity for load transfer and power supply. Especially during the process of load transfer and power supply, it can still meet the temporary power demand of electric vehicles of a certain capacity and power supply facilities in remote locations.

[0091] The substation controller is the core equipment for implementing intelligent management of distribution network substations. The configuration of the substation controller in the power supply system is as follows: Figure 3 The functions of the area controller cover power balance and distribution, area data collection and monitoring, fault detection and processing, demand response and load control. This embodiment designs the control strategy of key processes and functions such as triggering of load transfer and power protection technology, V2G facility quantity allocation and power coordinated optimization allocation, which are controlled by the area controller, including:

[0092] 1) Trigger control strategy for hybrid V2G facilities

[0093] When a power outage occurs in the substation, the substation controller first collects and analyzes the changes in the substation voltage, frequency and power (i.e. rated capacity), and sends a trigger signal to the hybrid V2G facility, as shown in the following formula:

[0094] ,

[0095] in, C Trigger Indicates the V2G facility trigger signal (1 is a trigger signal, 0 is a non-trigger signal); V T Indicates the bus voltage of the substation area. V T,max and V T,min They represent the maximum and minimum thresholds of the bus voltage in the substation under normal conditions respectively; f T Indicates the frequency of the station area. f T,max and f T,min They respectively represent the maximum and minimum thresholds of the frequency in the area under normal conditions; P T Indicates the rated capacity of the area. P T,th Indicates the rated capacity threshold of the substation; Δ P T Indicates the fluctuation of the rated capacity of the station area, Δ P T,th Indicates the fluctuation threshold of the rated capacity of the substation; S em Signals other types of emergency power outages.

[0096] 2) Quantity allocation control strategy for hybrid V2G facilities

[0097] Fixed V2G facilities have faster response and higher reliability than mobile V2G facilities. The rated power of fixed AC V2G facilities is smaller than that of DC. In order to save the power supply capacity of V2G facilities and improve the capacity utilization of V2G facilities in power supply, in the process of load transfer and power supply, the priority of V2G facility types is set from high to low to fixed DC V2G facilities, fixed AC V2G facilities and mobile V2G facilities. The algorithm setting of this control strategy is shown in the following formula:

[0098] ,

[0099] in, n FA , n FD , n M They respectively represent the number of fixed DC V2G facilities, fixed AC V2G facilities, and mobile V2G facilities allocated by the substation controller to participate in power supply protection; P FA,max , P FD,max and P M,max They respectively represent the maximum rated power of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities.

[0100] 3) Power Co-optimization Allocation of Hybrid V2G Facilities

[0101] In order to minimize the comprehensive operating cost of hybrid V2G facilities, it is necessary to further optimize the power allocation of different types of V2G facilities according to the constraints of various types of V2G facilities during the load transfer and power supply process, as shown in the following formula:

[0102] ,

[0103] in, P FA,t , P FD,t , P M,t and P T,t They represent the fixed AC V2G facilities, fixed DC V2G facilities, mobile V2G facilities and the load in the substation. t Real-time power at all times; C FA , C FD and C MRespectively represent the operating costs of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities; SOC FA,t , SOC FD,t and SOC M,t Respectively represent the fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities in t The real-time state of charge (SOC) at the moment; the subscripts max and min represent the maximum and minimum values ​​of the real-time state of charge SOC, respectively.

[0104] For different power failure ranges and power failure situations, such as Figure 2 The main implementation steps of load transfer and power supply protection in the substation area include:

[0105] Step 1: Determine the power failure range according to the number of power failure areas, and further calculate the power failure load capacity;

[0106] Step 2: Determine the power failure scenario based on the power failure scope. The substation controller corresponding to the power failure substation compares the power failure load capacity with the power protection capacity to determine the power failure situation, thereby determining the type and number of V2G facilities required for power protection.

[0107] For power outage situation 5, the substation controller calculates the difference between the V2G power conservation capacity and the power outage load Δ P IM = P Loss - P V2G ; Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss - Δ P IM );based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required to maintain power, and the coordinated optimization allocation of power maintenance capacity;

[0108] When the power failure range exceeds one area, each area controller calculates the difference between the V2G power protection capacity and the power failure load Δ P IM = P Loss - P V2G , and add up the total difference of each area to get Δ P IM,sum , and based on the total difference ΔP IM,sum According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss -Δ P IM,sum ),based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required for power protection and the coordinated and optimized allocation of power protection capacity to different substations.

[0109] Step 3: The power-off load in the substation is transferred to the power-protection branch of the V2G facility, which includes:

[0110] Switch the power-protected V2G facilities to the switch contacts of the corresponding power-protected station area;

[0111] The power protection branch switch of the corresponding substation is closed;

[0112] The corresponding area load protection switch is closed, and the corresponding area load branch switch is opened;

[0113] The power-lost load in the substation area is transferred to the power-protection branch of the V2G facility;

[0114] For power outage situation 5, when the power outage range does not include the branch of the substation that supplies power to the V2G facility, the power protection branch switch of the substation that supplies power to the V2G facility is opened.

[0115] Step 4: The V2G facilities participating in the power supply protection are supplied with power at the same time, and the V2G facilities not participating in the power supply protection continue to be connected to the substation that supplies power to the V2G facilities through the switch contacts, and continue to maintain the original power supply mode and function.

[0116] This embodiment also relates to a method for efficiently transferring and protecting power supply in a substation area based on a hybrid V2G facility. Figure 1 Taking the residential power supply system topology as an example, the main implementation steps of load transfer and power supply protection in the substation area are as follows:

[0117] a) The power failure range is 1 station area

[0118] Based on the classification and summary of the power outage situations in the substations described in Table 1, taking the power outage of L2 and L3 units in substation 1 due to a fault as an example, the main implementation steps of load transfer and power protection in the substation in scenario 1 are as follows:

[0119] (a1) The main implementation steps of load transfer and power protection in the substation in case 1 are: Substation 1 controller P LossDetermine the power failure situation and determine the number of FA-V2G facilities required to maintain power → FA1-V2G or FA2-V2G (or FA1-V2G and FA2-V2G at the same time) switch to switch contact 1 → power branch switch QS v 1 Close → load protection switch QS 12 With QS 13 Close → load branch switch S 12 With S 13 Open → The power-off load in the substation is transferred to the power-saving branch of the V2G facility → FA1-V2G or FA2-V2G (or FA1-V2G and FA2-V2G at the same time, determined according to the actual situation) supplies power → The V2G facilities that are not involved in the power protection can continue to be connected to the substation 3 through the switch contact 3 to continue to maintain the original power supply mode and function;

[0120] (a2) The main implementation steps of load transfer and power protection in the substation in case 2 are: Substation 1 controller P Loss Determine the power failure situation and determine the number of FD-V2G facilities required to maintain power → FD1-V2G or FD2-V2G (or FD1-V2G and FD2-V2G at the same time) switch to switch contact 1 → power branch switch QS v 1 Close → load protection switch QS 12 With QS 13 Close → load branch switch S 12 With S 13 Open → The power-off load in the substation is transferred to the power-saving branch of the V2G facility → FD1-V2G or FD2-V2G (or FD1-V2G and FD2-V2G at the same time) supplies power → The V2G facilities that are not involved in the power protection can continue to be connected to the substation 3 through the switch contact 3 to continue to maintain the original power supply mode and function;

[0121] (a3) The main implementation steps of load transfer and power protection in the substation in case 3 are: Substation 1 controller P Loss Determine the power outage situation and determine the number of FA-V2G and FD-V2G facilities required to maintain power (e.g. P Loss Requires 2 FD-V2Gs and 1 FA-V2G) → FD1-V2G, FD2-V2G and any FA-V2G switch to switch contact 1 at the same time → power branch switch QS v 1 Close → load protection switch QS 12 With QS 13 Close → load branch switch S 12 With S 13Open → The power-off load in the substation is transferred to the power-saving branch of the V2G facility → FD1-V2G, FD2-V2G and any one FA-V2G discharge at the same time → The V2G facilities not participating in the power-saving can continue to be connected to the substation 3 through the switch contact 3 to continue to maintain the original power supply mode and function;

[0122] (a4) The main implementation steps of load transfer and power protection in the substation in case 4 are: Substation 1 controller P Loss Determine the power outage situation and determine the number of FA-V2G, FD-V2G and FM-V2G facilities required to maintain power (e.g. P Loss Requires 2 FA-V2G, 2 FA-V2G and 1 FM-V2G) → 2 FA-V2G, 2 FA-V2G and 1 FM-V2G and any 1 FM-V2G switch to switch contact 1 at the same time → power branch switch QS v 1 Close → load protection switch QS 12 With QS 13 Close → load branch switch S 12 With S 13 Open → The power-off load in the substation is transferred to the power-saving branch of the V2G facility → 2 FA-V2Gs, 2 FA-V2Gs and 1 FM-V2G are discharged at the same time → The V2G facilities that are not involved in the power-saving can continue to be connected to the substation 3 through the switch contact 3 to continue to maintain the original power supply mode and function;

[0123] (a5) The main implementation steps of load transfer and power protection in the substation in case 5 are as follows: Substation 1 controller calculates the difference between V2G power protection capacity and power loss load Δ P IM = P Loss - P V2G →Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss -Δ P IM ) → Based on P GS Determine the power failure situation, so as to determine the type and quantity of V2G facilities required for power protection and the coordinated optimization allocation of power protection capacity → V2G facilities involved in power protection are switched to switch contact 1 at the same time → Power protection branch switch QS v 3 Open → Power-saving branch switch QSv 1 Close → load protection switch QS 12 With QS 13 Close → load branch switch S 12 With S 13 Open → The power-lost load in the substation is transferred to the power-saving branch of the V2G facility → All V2G facilities involved in power protection discharge at the same time.

[0124] The main difference between scenario 2 and scenario 1 is that the power supply area 3 of the lost station is the power supply area of ​​the V2G facility and other power supply loads belong to public power facilities. Therefore, the main implementation steps of the load transfer and power protection in the area of ​​scenario 2 are basically the same as those in scenario 1. The main difference is that the load conversion method of the power supply branch of the V2G facility area in area 3 is different from the power flow conversion of the V2G facility.

[0125] Assume that the power supply branch of the monitoring and fire pump in substation 3 loses power due to a fault. Taking situation 5 as an example, the main implementation steps of load transfer and power protection at this time are: the controller of substation 3 calculates the difference between the V2G power protection capacity and the power failure load Δ P IM = P Loss - P V2G →Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss -Δ P IM ) → Based on P GS Determine the power failure situation, so as to determine the type and quantity of V2G facilities required for power protection and the coordinated optimization allocation of power protection capacity → V2G facilities involved in power protection are switched to switch contact 1 at the same time → Power protection branch switch QS v 3 Keep closed → load protection switch QS 36 Close → load protection switch QS 32 With QS 33 Close → load branch switch S 32 With S 33 Open → The power-losing load in the substation is transferred to the power-saving branch of the V2G facility → All V2G facilities involved in power protection discharge at the same time → Electric vehicle charging or other remote power loads in the community are temporarily implemented by the remaining mobile V2G facilities (if there are sufficient mobile V2G facilities).

[0126] In scenario 3, the main transformer or busbar in the substation fails or is under maintenance, causing a total power outage in the substation. The main difference between the load transfer and power protection operations in scenario 3 and the previous two scenarios is that all substation power supply branches need to be transferred to the power protection branches of the V2G facilities, and the substation controller evaluates and allocates the corresponding power protection capacity.

[0127] Taking the power outage situation 5 of the substation 1 in scenario 3 as an example, the main implementation steps of load transfer and power protection at this time are: the controller of substation 1 calculates the difference between the V2G power protection capacity and the power outage load Δ P IM = P Loss - P V2G →Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS →Based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required for power protection and the power protection capacity allocation of all power-off branches → V2G facilities involved in power protection are switched to switch contact 1 at the same time → Power protection branch switch QS v 3 Open → Power-saving branch switch QS v 1 Close → switch QS 12 ~QS 16 All closed → load branch switch S 11 ~S 16 All are turned on → All power-lost loads in the substation area are transferred to the power supply branch of the V2G facility → All V2G facilities participating in the power supply are supplied at the same time → Electric vehicle charging or other remote power loads in the community are temporarily implemented by mobile V2G facilities that are not involved in the power supply (if there are sufficient mobile V2G facilities).

[0128] b) The power failure range is 2 stations

[0129] The power outage covers two substations, including four power outage scenarios. The main implementation steps of Scenario 4 and Scenario 1, Scenario 5 and Scenario 2 are basically the same, and the main implementation steps of Scenario 6 and Scenario 7 are basically the same as Scenario 3. The main difference between the above scenarios is that Scenarios 4 to 7 require the substation controller to simultaneously allocate the power conservation power of the V2G facilities to two different substations.

[0130] b1) Taking the power outage situation 5 in scenario 4 as an example, the main implementation steps of load transfer and power protection at this time are: the controllers of the substations 1 and 2 respectively calculate the difference between the V2G power protection capacity and the power outage load Δ P IM = PLoss - P V2G , and add up the total difference between the two areas Δ P IM,sum →Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss -Δ P IM，sum ) → Based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required for power protection and the coordinated optimization allocation of power protection capacity to different substations → V2G facilities participating in power protection in substation 1 are switched to switch contact 1 at the same time, and V2G facilities participating in power protection in substation 2 are switched to switch contact 2 at the same time → Power protection branch switch QS v 3 Open → Power-saving branch switch QS v 1 With QS v 2 Close → The corresponding load protection switches (QS) of the power-off load branches in substations 1 and 2 are closed → The corresponding load branch switches (S) of the power-off load branches in substations 1 and 2 are opened → The power-off load in the substation is transferred to the power protection branch of the V2G facility → All V2G facilities participating in the power protection supply power at the same time → Electric vehicle charging or other remote power loads in the community are temporarily implemented by mobile V2G facilities that are not involved in the power protection (if there are sufficient mobile V2G facilities).

[0131] b2) Taking the power outage situation 5 of area 1 and area 3 in scenario 7 as an example, the main implementation steps of load transfer and power protection at this time are: the controllers of area 1 and area 3 respectively calculate the difference Δ between the V2G power protection capacity and the power outage load P IM = P Loss - P V2G , and add up to get the total difference Δ P IM,sum →Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss -Δ PIM,sum ) → Based on P GS Determine the power outage situation, and determine the type and quantity of V2G facilities required for power protection, as well as the power protection capacity allocation to all power-off branches in different substations → V2G facilities participating in power protection in substation 1 are switched to switch contact 1 at the same time → Power protection branch switch QS v 3 Keep closed → power-saving branch switch QS v 1 Close → All corresponding load protection switches QS of all power-off load branches in substations 1 and 3 are closed → All corresponding load branch switches (S) of power-off load branches in substations 1 and 3 are opened → All power-off loads in the substation are transferred to the power protection branch of the V2G facilities → All V2G facilities participating in the power protection supply power at the same time → Electric vehicle charging or other remote power loads in the community are temporarily implemented by mobile V2G facilities that are not involved in the power protection (if there are sufficient mobile V2G facilities).

[0132] c) The power failure range is 3 stations

[0133] The power outage covers 3 substations, which includes 2 power outage scenarios. The main implementation steps of Scenario 8 are basically the same as those of Scenario 1, Scenario 2, Scenario 4, and Scenario 5. The main implementation steps of Scenario 9 are basically the same as those of Scenario 3, Scenario 6, and Scenario 7. The main difference from the above scenarios is that Scenario 8 and Scenario 9 require the substation controller to simultaneously allocate the power conservation power of the V2G facilities to 3 different substations.

[0134] Taking the power outage situation 5 in scenario 8 as an example, the main implementation steps of load transfer and power protection at this time are: the controllers of substations 1, 2 and 3 calculate the difference between the V2G power protection capacity and the power outage load Δ P IM = P Loss - P V2G , and add up to get the total difference Δ P IM,sum →Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss -Δ P IM,sum ) → Based on P GSDetermine the power outage situation, so as to determine the type and quantity of V2G facilities required for power protection and the coordinated optimization allocation of power protection capacity to different substations → V2G facilities participating in power protection in substation 1 are switched to switch contact 1 at the same time, and V2G facilities participating in power protection in substation 2 are switched to switch contact 2 at the same time → Switch QS v 3 Keep closed → switch QS v 1 With QS v 2 Close → The corresponding load protection switches QS of the power-off load branches in substations 1, 2 and 3 are closed → The corresponding load branch switches S of the power-off load branches in substations 1, 2 and 3 are opened → The power-off load in the substation is transferred to the power protection branch of the V2G facility → All V2G facilities participating in the power protection supply power at the same time → Electric vehicle charging or other remote power loads in the community are temporarily implemented by mobile V2G facilities that are not involved in the power protection (if the number of mobile V2G facilities is sufficient).

[0135] Taking the power outage situation 5 in scenario 9 as an example, the main implementation steps of load transfer and power protection at this time are: the controllers of substations 1, 2 and 3 respectively calculate the difference between the V2G power protection capacity and the power outage load Δ P IM = P Loss - P V2G , and add up to get the total difference Δ P IM,sum →Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ( P GS = P Loss -Δ P IM,sum ) → Based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required for power protection and the allocation of power protection capacity to all power-lost branches in different substations → V2G facilities participating in power protection in substation 1 are switched to switch contact 1 at the same time, and V2G facilities participating in power protection in substation 2 are switched to switch contact 2 at the same time → Switch QS v 3 Keep closed → switch QS v 1 With QS v 2Close → All corresponding area load protection switches QS of all power-off load branches in area 1, area 2 and area 3 are closed → All corresponding area load branch switches S of all power-off load branches in area 1, area 2 and area 3 are opened → All power-off loads in the area are transferred to the power protection branch of the V2G facility → All V2G facilities participating in the power protection supply power at the same time → Electric vehicle charging or other remote power loads in the community are temporarily implemented by mobile V2G facilities that are not involved in the power protection (if there are sufficient mobile V2G facilities).

[0136] The V2G load transfer circuit topology and conversion technology assisted by hybrid V2G facilities has a load transfer and power protection implementation process for different power outages in different areas, fully adapting to different power outage scenarios and power outages, and improving the comprehensiveness and reliability of power protection. V2G users and suppliers can obtain corresponding benefits from load transfer and power protection in the area, which can significantly increase the enthusiasm of users to participate in load dedicated supply and power protection, and bring additional economic and social benefits.

[0137] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for efficient power transfer and power protection of loads in a substation based on hybrid V2G facilities, characterized in that: The hybrid V2G facility includes a fixed AC V2G facility, a fixed DC V2G facility and a mobile V2G facility, and the method includes: Step 1: Determine the power failure range according to the number of power failure areas, and further determine the power failure load capacity; Step 2: Determine the power failure scenario based on the power failure scope, compare the power failure load capacity with the power protection capacity to determine the power failure situation, and thus determine the type and number of V2G facilities required for power protection and the coordinated optimization allocation of the power protection capacity; Step 3: according to the result of step 2, the power-off load in the substation is transferred to the power-protection branch of the V2G facility; Step 4: The hybrid V2G facilities participating in power protection provide power to the corresponding power-lost branches at the same time, and the hybrid V2G facilities not participating in power protection maintain the original access, operation mode and functions; The load capacity will be lost P Loss Compared with the power-saving capacity, the process of judging the power failure situation includes: like P Loss ≤ P FA , it is judged as the first power failure situation; like P FA < P Loss ≤ P FD , it is judged as the second power failure situation; like P FD < P Loss ≤ P F , it is judged as the third power failure situation; like P F < P Loss ≤ P V2G , it is judged as the fourth power failure situation; like P V2G < P Loss , it is judged as the fifth power failure situation; in P FA is the total power of fixed AC V2G facilities; P FD is the total power of fixed DC V2G facilities; P F is the total power of fixed V2G facilities, P F = P FA + P FD ; P V2G The total power of all V2G facilities is: P V2G = P F + P M , P M is the total power of mobile V2G facilities; The total power of each V2G facility meets P FA <P FD <P F <P V2G； The types and quantities of V2G facilities required for power supply protection in step 2 are as follows: ， ， in, n FA , n FD and n M They respectively represent the number of fixed DC V2G facilities, fixed AC V2G facilities and mobile V2G facilities allocated by the substation controller to participate in power supply protection; P FA,max , P FD,max and P M,max Respectively represent the maximum rated power of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities; N FA , N FD and N M They are the number of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities; P Loss is the power-off load capacity; [ ] is the rounding symbol; The selection priorities of the hybrid V2G facilities are set from high to low as fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities.

2. According to claim 1, a method for efficient power transfer and power protection of load in a substation based on hybrid V2G facilities is characterized in that: The power failure scenario is determined according to the power failure range of the substation area, including: If the power outage covers part of a branch of a substation, and the substation is not a V2G facility or a public power supply substation, the power outage scenario is the first scenario; If the power outage covers part of a branch of a substation, and the substation is a V2G facility and public power supply substation, the power outage scenario is the second scenario; If the power outage covers the entire area of ​​a transformer substation, the power outage scenario is the third scenario; If the power outage covers multiple substations, and some branches of each substation lose power, and these substations are not V2G facilities or public power supply substations, then the power outage scenario is the fourth scenario; If the power outage covers multiple substations, some branches of each substation lose power, and one of the substations is a V2G facility and public power supply substation, the power outage scenario is the fifth scenario; If the power outage covers multiple substations, all branches in each substation lose power, and these substations are not V2G facilities or public power supply substations, the power outage scenario is the sixth scenario; If the power outage covers multiple substations, all branches in each substation lose power, and one of the substations is a V2G facility and public power supply substation, the power outage scenario is scenario 7; If the power outage covers all substations and some branches in each substation lose power, the power outage scenario is scenario 8; If the power outage covers all substations and all branches in each substation lose power, the power outage scenario is scenario nine.

3. According to claim 1, a method for efficient power transfer and power protection of load in a substation based on hybrid V2G facilities is characterized in that: In the fifth power outage situation, since the total V2G power protection capacity cannot meet the power outage load capacity, some important loads in the substation are selected for power protection, and some non-important loads are discarded.

4. According to claim 1, a method for efficient power transfer and power protection of load in a substation based on hybrid V2G facilities is characterized in that: The collaborative optimization allocation of the power conservation capacity includes: setting constraints on V2G facilities, collaboratively optimizing the power allocation of different types of V2G facilities, and minimizing the comprehensive operating cost of hybrid V2G facilities, specifically: ， in, P FA,t , P FD,t , P M,t and P T,t They represent the fixed AC V2G facilities, fixed DC V2G facilities, mobile V2G facilities and the load in the substation. t Real-time power at all times; C FA , C FD and C M They represent the operating costs of fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities respectively; SOC FA,t , SOC FD,t and SOC M,t Respectively represent the fixed AC V2G facilities, fixed DC V2G facilities and mobile V2G facilities in t The real-time state of charge SOC at the moment; the subscripts max and min represent the maximum and minimum values ​​of the real-time state of charge SOC respectively; TH Indicates the total time that V2G facilities participate in power supply protection.

5. According to claim 1, a method for efficient power transfer and power protection of load in a substation based on hybrid V2G facilities is characterized in that: The process of transferring the power-lost load in the substation area to the power-protection branch of the V2G facility includes: Switch the power-protected V2G facilities to the switch contacts of the corresponding power-protected station area; The power protection branch switch of the corresponding substation is closed; The corresponding area load protection switch is closed, and the corresponding area load branch switch is opened; The power-lost load in the substation is transferred to the power supply branch of the V2G facility.

6. The method for efficient power transfer and power protection of load in a substation area based on hybrid V2G facilities according to claim 1 is characterized in that: For the fifth power outage situation, when the power outage does not involve V2G facilities and public power supply stations, the power protection branch switches of the V2G facilities and public power supply stations are opened.

7. The method for efficient power transfer and power protection of load in a substation area based on hybrid V2G facilities according to claim 1 is characterized in that: For the fifth power outage situation, the substation controller calculates the V2G power conservation capacity P V2G Power failure load capacity P Loss The difference Δ P IM = P Loss - P V2G ; Based on Δ P IM According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ,in P GS = P Loss - Δ P IM ;based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required to maintain power, and coordinate the optimal allocation of power maintenance capacity.

8. The method for efficient power transfer and power protection of load in a substation area based on hybrid V2G facilities according to claim 1 is characterized in that: When the power outage range exceeds one area, each area controller calculates the V2G power conservation capacity separately. P V2G Difference with power failure load capacity Δ P IM = P Loss - P V2G , and add up the total difference of each area to get Δ P IM,sum , and based on the total difference Δ P IM，sum According to the load importance assessment, the load capacity that can be abandoned and the new load that needs to be protected can be P GS ,in P GS = P Loss -Δ P IM,sum ;based on P GS Determine the power outage situation, so as to determine the type and quantity of V2G facilities required to maintain power, and coordinate the optimal allocation of power maintenance capacity.

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