阅读说明：本技术 一种基于电动工程车的配电网保供电方法 (Power distribution network power protection and supply method based on electric engineering vehicle ) 是由 杜兆斌 黄俊杰 吴佳润 玉少华 覃鸿钧 黄润烽 徐征 于 2021-07-08 设计创作，主要内容包括：本发明公开了一种基于电动工程车的配电网保供电方法,该方法包括下述步骤：结合检修环境、类型、影响用户程度的历史数据和电动汽车市场情况,配置不同规模、车型、电池容量的电动汽车作为电动工程车；预设电动工程车充电方式；根据电动工程车出行抢检修和停电负荷需求,建立电动工程车优化调度模型；结合电动工程车荷电状态、路况信息,采用模拟退火算法规划最优的行驶路线；电动工程车电源接入用户低压配电系统,电动工程车电源切换到逆变放电模式向负荷供电；根据电网公司调度中心预测的停电区域负荷曲线,计算设定约束下最小功率偏差,计算最优电动工程车电池输出功率。本发明有利于保障用户在停电期间的电能需求,从而提高配电网供电可靠性。(The invention discloses a power distribution network power protection and supply method based on an electric engineering truck, which comprises the following steps: configuring electric automobiles with different scales, vehicle types and battery capacities as electric engineering vehicles by combining the maintenance environment, the type, the historical data influencing the user degree and the market condition of the electric automobiles; presetting a charging mode of the electric engineering truck; establishing an optimized dispatching model of the electric engineering truck according to the trip maintenance and power failure load requirements of the electric engineering truck; planning an optimal driving route by adopting a simulated annealing algorithm in combination with the charge state and road condition information of the electric engineering vehicle; the power supply of the electric engineering truck is connected to a user low-voltage power distribution system, and the power supply of the electric engineering truck is switched to an inversion discharge mode to supply power to a load; and calculating the minimum power deviation under the set constraint according to the load curve of the power failure area predicted by the dispatching center of the power grid company, and calculating the optimal battery output power of the electric engineering vehicle. The invention is beneficial to guaranteeing the electric energy requirement of a user during the power failure, thereby improving the power supply reliability of the power distribution network.)

1. A power distribution network power protection and supply method based on an electric engineering vehicle is characterized by comprising the following steps:

configuring electric automobiles with different scales, vehicle types and battery capacities as electric engineering vehicles by combining the maintenance environment, the type, the historical data influencing the user degree and the market condition of the electric automobiles;

presetting a charging mode of the electric engineering truck;

establishing an optimized dispatching model of the electric engineering truck according to the requirements of trip maintenance and power failure load of the electric engineering truck;

planning an optimal driving route by adopting a simulated annealing algorithm in combination with the charge state and road condition information of the electric engineering vehicle;

the power supply of the electric engineering truck is connected to a user low-voltage power distribution system, and the power supply of the electric engineering truck is switched to an inversion discharge mode to supply power to a load;

and calculating the minimum power deviation under the set constraint according to the load curve of the power failure area predicted by the dispatching center of the power grid company, and calculating the optimal battery output power of the electric engineering vehicle.

2. The power protection and supply method for the power distribution network based on the electric engineering vehicle as claimed in claim 1, wherein the preset charging mode of the electric engineering vehicle is a combination of slow charging and fast charging, an electric quantity threshold value for switching the charging mode is set, when the preset electric quantity threshold value is lower than the preset electric quantity threshold value, the electric quantity threshold value is charged in a fast charging mode, and when the preset electric quantity threshold value is higher than the preset electric quantity threshold value, the electric quantity threshold value is charged in a slow charging mode until the next trip task is started or the electric quantity reaches the preset upper limit value.

3. The power protection and supply method for the power distribution network based on the electric engineering vehicle as claimed in claim 1, wherein the optimal scheduling model of the electric engineering vehicle is established by the following specific calculation formula:

min n

the constraint conditions are as follows:

wherein, C_iIndicates the electric quantity n that the ith electric engineering vehicle can provide_iIndicating the number of the ith electric engineering vehicles connected to the power grid at each time, k_iThe number of times P that the ith electric engineering vehicle needs to move due to the limitation of the battery capacity in the whole process is shown_iThe maximum discharge power of the ith type of electric engineering vehicle is represented, L is the size of the power failure load, k is the percentage of the actual discharge power of the electric engineering vehicle to the maximum discharge power, T is the expected power failure time, i is the type of the ith type of electric engineering vehicle, n_i，min、n_i，maxThe minimum quantity and the maximum quantity of the ith electric engineering truck are respectively; k is a radical of_i，min、k_i，maxThe minimum and maximum running times of the ith electric engineering truck are respectively.

4. The electric engineering vehicle-based power distribution network power protection and supply method according to claim 1, wherein the optimal driving route is planned by adopting a simulated annealing algorithm, and the specific steps comprise:

setting random path initial solution x₀Initial temperature T₀Attenuation coefficient K, termination temperature threshold T_th；

Obtaining a new driving route p by adopting an exchange method_i+1And the total running distance S_i+1；

If S_i+1-S_iWhen p is less than or equal to 0, p is added_i+1Substituting the new solution into the original calculation step to continue iterative solution;

if S_i+1-S_iIf > 0, thenProbability of accepting p_i+1As a new solution, otherwise still with p_iAs the solution for the next iteration;

from T₀At first, slowly lowering the temperature according to T (i +1) ═ KT (i), and continuously weighingRepeating the iterative process until the temperature T is equal to T_thAnd stopping calculation, and outputting the optimal solution to obtain the optimal route result of the electric engineering truck.

5. The power protection and supply method for the power distribution network based on the electric engineering vehicle as claimed in claim 1, wherein a power supply of the electric engineering vehicle is connected to a user low-voltage power distribution system by adopting a quick plug connector, an outgoing cable and a portable access device;

the electric engineering truck is connected with a quick plugging connector, the quick plugging connector is connected with an outgoing cable, the outgoing cable is connected with a portable access device, and the portable access device is connected with a low-voltage distribution transformer of a user low-voltage distribution system.

6. The power protection and supply method for the power distribution network based on the electric engineering vehicle as claimed in claim 1, wherein the step of calculating the optimal battery output power of the electric engineering vehicle comprises the following specific steps:

the constraint conditions are as follows:

wherein, L (t) represents a power failure area load curve obtained by forecasting of a dispatching center of a power grid company, P_max、P_minThe maximum output power and the minimum output power of the battery of the electric engineering vehicle are respectively, and delta t is a time interval.

Technical Field

The invention relates to the technical field of power distribution network power protection, in particular to a power distribution network power protection method based on an electric engineering vehicle.

Background

With the development of electrification and intellectualization, electric power plays an extremely important role in the fields of construction and development. However, in life, the possibility of a power outage for the user always exists. At present, measures for improving the power supply reliability of a low-voltage distribution network mainly comprise: the method has the advantages of improving the automation level of the distribution network, perfecting the framework of the distribution network, adopting a substation pavilion or box type transformer to replace a rod frame type distribution transformer, configuring energy storage equipment at a user side, protecting and supplying power for a power generation car and the like. The partial measures of the scheme have large scale and high cost, and are difficult to be completely realized in a short time; for the power generation cars, power supply departments are equipped, but the power generation cars are difficult to go deep into narrow blocks due to large appearance, and the use scenes are limited.

Disclosure of Invention

In order to overcome the defects and shortcomings in the prior art, the invention provides the power protection and supply method for the power distribution network based on the electric engineering vehicle.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a power distribution network power protection and supply method based on an electric engineering vehicle, which comprises the following steps:

configuring electric automobiles with different scales, vehicle types and battery capacities as electric engineering vehicles by combining the maintenance environment, the type, the historical data influencing the user degree and the market condition of the electric automobiles;

presetting a charging mode of the electric engineering truck;

establishing an optimized dispatching model of the electric engineering truck according to the requirements of trip maintenance and power failure load of the electric engineering truck;

planning an optimal driving route by adopting a simulated annealing algorithm in combination with the charge state and road condition information of the electric engineering vehicle;

the power supply of the electric engineering truck is connected to a user low-voltage power distribution system, and the power supply of the electric engineering truck is switched to an inversion discharge mode to supply power to a load;

and calculating the minimum power deviation under the set constraint according to the load curve of the power failure area predicted by the dispatching center of the power grid company, and calculating the optimal battery output power of the electric engineering vehicle.

As a preferred technical scheme, the preset charging mode of the electric engineering truck specifically adopts a mode of combining slow charging and fast charging, the electric quantity threshold value for switching the charging mode is set, when the electric quantity threshold value is lower than the set electric quantity threshold value, the electric quantity threshold value is charged by adopting the fast charging mode, and when the electric quantity threshold value is higher than the set electric quantity threshold value, the electric quantity threshold value is charged by adopting the slow charging mode to the next trip task or the electric quantity reaches the set upper limit value.

As a preferred technical scheme, the establishing of the optimal scheduling model of the electric engineering truck has a specific calculation formula as follows:

min n

the constraint conditions are as follows:

wherein, C_iIndicates the electric quantity n that the ith electric engineering vehicle can provide_iIndicating the number of the ith electric engineering vehicles connected to the power grid at each time, k_iElectric engineering of i-th kind for representing whole processNumber of required trips of vehicle due to battery capacity limitation, P_iThe maximum discharge power of the ith type of electric engineering vehicle is represented, L is the size of the power failure load, k is the percentage of the actual discharge power of the electric engineering vehicle to the maximum discharge power, T is the expected power failure time, i is the type of the ith type of electric engineering vehicle, n_i,min、n_i,maxThe minimum quantity and the maximum quantity of the ith electric engineering truck are respectively; k is a radical of_i,min、k_i,maxThe minimum and maximum running times of the ith electric engineering truck are respectively.

As a preferred technical scheme, the planning of the optimal driving route by using the simulated annealing algorithm specifically comprises the following steps:

setting random path initial solution x₀Initial temperature T₀Attenuation coefficient K, termination temperature threshold T_th；

Obtaining a new driving route p by adopting an exchange method_i+1And the total running distance S_i+1；

If S_i+1-S_iWhen p is less than or equal to 0, p is added_i+1Substituting the new solution into the original calculation step to continue iterative solution;

if S_i+1-S_iIf > 0, thenProbability of accepting p_i+1As a new solution, otherwise still with p_iAs the solution for the next iteration;

from T₀Starting, slowly reducing the temperature according to T (i +1) ═ KT (i), and continuously repeating the iteration process until the temperature T ═ T_thAnd stopping calculation, and outputting the optimal solution to obtain the optimal route result of the electric engineering truck.

As a preferred technical scheme, a power supply of the electric engineering truck is connected to a user low-voltage power distribution system and is connected with a quick plug-in connector, a wire outlet cable and a portable access device;

the electric engineering truck is connected with a quick plugging connector, the quick plugging connector is connected with an outgoing cable, the outgoing cable is connected with a portable access device, and the portable access device is connected with a low-voltage distribution transformer of a user low-voltage distribution system.

As a preferred technical scheme, the calculating of the optimal battery output power of the electric engineering truck specifically comprises the following steps:

the constraint conditions are as follows:

wherein, L (t) represents a power failure area load curve obtained by forecasting of a dispatching center of a power grid company, P_max、P_minThe maximum output power and the minimum output power of the battery of the electric engineering vehicle are respectively, and delta t is a time interval.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention provides a power distribution network power-guaranteeing and supplying method based on an electric engineering vehicle for exploring the power distribution network power-guaranteeing and supplying method, provides a set of power distribution network power-supplying reliability improvement scheme from vehicle configuration to reverse power transmission by combining the characteristics of the electric engineering vehicle, and provides reference for formulating a power supply department method for improving power supply reliability.

(2) According to the invention, the electric engineering truck is used as a mobile power supply to supply power to the affected user during power failure, and compared with the traditional maintenance scheme without the electric engineering truck, the power supply reliability of the user is effectively improved. For the power supply department, the economic benefit and the maintenance efficiency are improved; for a user, the power utilization level and the power utilization experience are improved, the electric engineering vehicle replaces a traditional fuel engineering vehicle and a power generation vehicle, the small sedan type and SUV type electric engineering vehicles with small sizes replace a large-scale electric engineering vehicle, most streets can be deeply penetrated, and the power supply is ensured to be in place.

Drawings

FIG. 1 is a schematic flow chart of a power distribution network power protection method based on an electric engineering vehicle;

FIG. 2 is a schematic diagram of a calculated route for determining an optimal driving route for the electric engineering truck according to the present invention;

fig. 3 is a structural diagram of a device for connecting the electric engineering vehicle to a power distribution network;

fig. 4 is a schematic diagram of the electric engineering vehicle connected to a low-voltage side power distribution network;

FIG. 5 is a simplified schematic diagram of a connection line between an electric work vehicle and a power distribution grid according to the present invention;

FIG. 6 is a flow chart of the electric engineering truck accessing the power distribution network after arriving at an operation site;

FIG. 7 is a radial wiring diagram of the distribution network of the present invention;

fig. 8 is a schematic diagram of the electric engineering truck battery SOC.

Wherein, 1-copper nose, 2-insulating sleeve, 3-cable, 4-current clamp.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Examples

As shown in fig. 1, the present embodiment provides a method for protecting and supplying power to a power distribution network based on an electric engineering vehicle, which issues an operation plan for an unexpected or planned power failure event; the terminal receives the operation task, and determines the type and the number of the electric engineering vehicles to be driven according to the analysis of the fault condition; analyzing the distance between the accident occurrence place and the power supply department and the road condition through navigation software, and determining an optimal driving route; during the maintenance operation, the electric engineering vehicle is used as a mobile power supply and is connected to a power distribution network through an interface device, and low-power electricity consumption for a period of time is provided for a user. In the embodiment, the electric engineering truck is used as a mobile power supply to supply power to affected users during power failure, and compared with the traditional maintenance scheme without the electric engineering truck, the power supply reliability of the users is effectively improved. For the power supply department, the economic benefit and the maintenance efficiency are improved; for users, the power utilization level and the power utilization experience are improved.

The method specifically comprises the following steps:

s1: considering economic benefits by combining historical data such as maintenance environment, types and influence on user degree and market conditions of electric automobiles, and configuring electric automobiles with different scales, vehicle types and battery capacities as electric engineering vehicles;

the electric engineering vehicle with multiple specifications can select car types and SUV types, the battery types mainly adopt ternary lithium batteries and blade batteries, the running electric energy loss under the general operation condition can be met, and more electric quantity can be reserved to provide electric energy. The embodiment can be provided with the electric engineering vehicles with different specifications by combining various factors such as the fund for purchasing the electric engineering vehicles, the road level and the load level in the controlled area and the distribution condition thereof, the number of equipment and personnel required to be carried in each outgoing operation and the like.

S2: presetting a charging mode of the electric engineering vehicle, executing charging work by the electric engineering vehicle, and waiting for issuing an operation instruction;

the electric engineering vehicle is not only a travel tool and a transport tool during the operation, but also needs to reserve certain electric quantity as a mobile power supply to provide electric energy for power failure load during power failure. Considering that the probability that the operation teams are arranged for maintenance work for many times in one day and the electric engineering vehicle is used for supplying power for the power failure load is low, the electric engineering vehicle selects a slow charging and quick charging combined mode. And when the electric engineering truck returns, the charging is started, the charging mode is selected according to whether the residual electric quantity reaches 60%, the quick charging mode is selected to be charged to 60% below 60%, and the slow charging mode is selected to be charged to the next trip task or the electric quantity reaches the upper limit when the residual electric quantity is higher than 60%.

S3: aiming at operations with different properties, namely prearranged power failure and fault power failure, preliminarily determining a power failure place, analyzing the place environment and the influence scale of the power failure accident, establishing an electric engineering truck optimized dispatching model, and determining electric engineering trucks of corresponding types and proper quantity to carry out maintenance work;

in this embodiment, an optimal scheduling model of the electric engineering vehicle is established, and a specific calculation formula is as follows:

min n

wherein, C_iIndicates the electric quantity n that the ith electric engineering vehicle can provide_iIndicating the number of the ith electric engineering vehicles connected to the power grid at each time, k_iThe number of times P that the ith electric engineering vehicle needs to move due to the limitation of the battery capacity in the whole process is shown_iThe maximum discharge power of the ith type of electric engineering vehicle is shown, and L is the size of a power failure load; k is the percentage of the actual discharge power of the electric engineering vehicle in the maximum discharge power; t is the expected power failure time; i is the ith electric engineering truck type, n_i,min、n_i,maxThe minimum quantity and the maximum quantity of the ith electric engineering truck are respectively; k is a radical of_i,min、k_i,maxRespectively the minimum and maximum running times of the ith electric engineering truck;

in the present embodiment, it is assumed that the types of electric working vehicles equipped are a sedan type and an SUV type, which have different maximum discharge powers of 20kW and 30kW, respectively;

the minimum total number of the electric engineering vehicle needing to be driven, namely the minimum n value, is obtained according to the following formula, and an optimized dispatching model is established according to the requirements of electric engineering vehicle for rush repair and power failure load during traveling:

min n

wherein, C₁、C₂The electric quantity can be provided for the sedan type electric engineering vehicle and the SUV type electric engineering vehicle respectively; n is₁、n₂Respectively the number of sedan models and SUV electric engineering vehicles which are connected into the power grid each time; k is a radical of₁、k₂Respectively representing the whole process car model and SUV type electric engineering vehicleThe number of times of tripping due to battery capacity limitation; l is the size of the power failure load; k is the percentage of the actual discharge power of the electric engineering vehicle in the maximum discharge power; t is the expected power failure time; i is the ith type of electric engineering vehicle, wherein 1 represents a sedan type, and 2 represents an SUV type; n is_i,min、n_i,maxThe minimum quantity and the maximum quantity of the ith electric engineering truck are respectively; k is a radical of_i,min、k_i,maxThe minimum and maximum running times of the ith electric engineering truck are respectively.

The following are exemplified: in a certain operation task, a certain feeder line causes 80kW load power failure due to the fault of a power supply main line, the expected power failure time T needs 3 hours, and C₁＝60kW·h，C₂＝80kW·h，n_1,minAnd n_2,minAre all 0, n_1,maxAnd n_2,maxAre all 5, k_1,minAnd k_2,minAre all 1, k_1,maxAnd k_2,maxAll 3, establishing an optimized scheduling model as follows:

min n

in this embodiment, based on the Matlab platform Yalmip tool box and the Cplex solver, the optimal value of the optimal scheduling model is solved to obtain the optimal scheme n₁＝0，n₂＝3，k₁＝1，k₂When n is equal to 3, namely 3 electric engineering vehicles of the SUV type are determined to be launched at one time, the total number of the launched vehicles can be minimized under the condition that the power supply requirement is met.

On the basis of the above formula, the types and the number of the electric engineering vehicles can be flexibly configured according to the actual conditions such as the number and the nature of users in an actual power failure area, the line condition of the power failure area, the distance and the road condition of an overhaul place and a power supply department, the number of operating personnel, the carrying of overhaul equipment and the like.

S4: before and during traveling, by combining the State of Charge (SOC) condition of the electric engineering vehicle, analyzing the route and road condition between the accident occurrence point and the power supply department by adopting navigation software, and determining the optimal planned route before and during traveling;

the following are exemplified: the nodes to be passed through and their coordinates in a certain job task are shown in table 1 below.

TABLE 1 electric engineering vehicle operation must pass node

After the assigned operation task is received, conditions such as SOC (system on chip) and road conditions of the electric engineering vehicle are considered, and nodes (such as fault troubleshooting nodes and charging pile nodes in long-distance operation tasks) which are necessary in the travel route are searched by combining navigation software. Typically, each node described above passes only once, so the problem can be translated into identifying a shortest travel route that passes only once through each must pass node. Then the optimized target mathematical expression is:

wherein x is_iIs the linear distance between two nodes; n is the total segment number of the distance between each node, and if the return route condition is considered, N is the node number.

The embodiment adopts a simulated annealing algorithm to solve the optimal path of the electric engineering truck. Setting random path as initial solution x in simulation degradation algorithm₀Initial temperature T₀Is 10⁴Attenuation coefficient K of 0.99, and termination temperature threshold T_thIs 10^-4。

Firstly, a new driving route p is obtained by using the exchange method_i+1And the total running distance S_i+1By comparison of S_i+1-S_iWhether it is greater than zero, whether it is decided to accept p_i+1As a new solution, if S_i+1-S_iWhen p is less than or equal to 0, p is added_i+1Substituting the new solution into the original calculation step to continue iterative solution; if S_i+1-S_iIf > 0, then Probability of accepting p_i+1As a new solution, otherwise still with p_iAs the solution for the next iteration. From T₀Starting, slowly reducing the temperature according to T (i +1) ═ KT (i), and continuously repeating the iteration process until the temperature T ═ T_thAnd (5) stopping calculation and outputting the optimal solution. And as shown in fig. 2, the optimal route result of the electric engineering vehicle is obtained.

S5: the method comprises the steps that when the electric engineering vehicle arrives at a power failure site, maintenance is carried out, a power distribution room corresponding to a user forced to have power failure is found, and the electric engineering vehicle is used as a mobile power supply to be connected to a low-voltage busbar of a load user;

in this embodiment, the method for accessing the power supply of the electric engineering truck to the low-voltage power distribution system of the user includes the steps of configuring an access device, determining the configuration of a wire cable, determining the access mode of the electric engineering truck and the like;

s51: configuring access devices

In order to meet the electricity demand of most users and improve the working efficiency, the existing flexible access mode is adopted, and the current portable access device is adopted in the embodiment, as shown in fig. 3, the device mainly comprises a copper nose 1, an insulating sleeve 2, a cable 3 and a current clamp 4. Wherein, current tong 4 adopts industrial pincers to reform transform, and the full insulating parcel of pincers body can pass through 800A electric current at the utmost, and the female arranging of user low pressure can easily be inserted through polishing in the interface face. The current clamp 4, the cable 3 and the copper nose 1 are integrally pressed, and the total length is about 100 cm. The cable is soft and can be crooked, and one section of cable is equipped with tensile insulating sheath to when docking access device and electric engineering car cable, wrap up with insulating sheath 2, prevent that the connection position from exposing outside and producing the mistake and bumping danger.

S52: determining the configuration of an electric cable

The electric engineering vehicle consists of a car type and an SUV type, and the power supply is a battery of the electric engineering vehicle and does not need a generator, so that the electric engineering vehicle is smaller than a common power generation vehicle in volume and can enter and exit most streets, residential districts and the like. Compared with the common power generation vehicle, the power supply power is lower, so that the outgoing cable does not need to be specially customized, and only the outgoing cable of the power supply of the common 0.4kV power generation vehicle needs to be equipped. Because the electric engineering vehicle has different vehicle types and has different space, horsepower and load capacity, cables with different lengths can be configured according to different vehicle types, in the embodiment, a sedan vehicle type is provided with 10 meters of outgoing cables, and an SUV vehicle type is provided with 30 meters of outgoing cables.

S53: determining access mode of electric engineering vehicle

As shown in fig. 4, an inverter module is disposed inside the electric engineering truck, and a three-phase four-wire is led out. After the line is connected on site, the low-voltage side of the low-voltage distribution transformer is connected to supply power to the load only by switching to an inversion discharge mode.

As shown in fig. 5, the connection relationship among the quick plug connector, the outgoing cable, and the portable access device is as follows: electric engineering vehicle-quick plug connector-outlet cable-portable access device-low voltage distribution transformer.

The outlet side of the electric engineering truck adopts the IP68 protection level quick plugging connector, the cable end connected with the user side adopts the portable access device, the plug and play effect of the cable on the engineering truck side and the user side can be realized, and the operation of operators is facilitated.

As shown in fig. 6, the specific steps of the access method using the portable access device are as follows: firstly, a high-low voltage incoming line switch needs to be opened, and a ground wire is hung; secondly, searching the position of a low-voltage bus bolt, and laying a cable; and finally, the outgoing line of the electric engineering truck is connected into the cable through the quick plug connector, the other end of the cable is connected to the copper nose of the portable access device, an operator can hold the access device by hand after insulation protection is performed, current is clamped into the low-voltage busbar, and power can be supplied to a user after the situation that no error exists is confirmed.

S6: and distributing electric energy to the users according to the number of the power failure users and the predicted power consumption and the discharge power of the electric engineering truck, and maintaining the low-power consumption of the users for a period of time.

In order to minimize the deviation between the output power of the electric engineering vehicle and the power failure load, the minimum power deviation delta P meeting the requirement is determined according to the power failure area load curve L (t) predicted by a dispatching center of a power grid company and the constraints of SOC, battery capacity, active output and the like of the electric engineering vehicle so as to determine the optimal battery output power P (t) of the electric engineering vehicle.

Wherein, P_max、P_minRespectively outputting the maximum and minimum output power of the battery of the electric engineering truck; Δ t is the time interval, which is 0.5 hour in this example.

The following are exemplified: as shown in fig. 7, in the small-sized distribution network, the load 2 is powered off due to a line fault, and the load 2 is continuously supplied with electricity for at least 3 hours by using a car-type electric working vehicle having a battery capacity C of 70kW · h, and the SOC lower limit value m is set to 20% in accordance with the traveling route of the electric working vehicle. Based on the load history data of the blackout area, the grid company dispatching center predicts a load curve of the load 2 within 3 hours of the electric engineering vehicle performing the task, as shown in table 2 below.

TABLE 2 load 2 predicted load curve parameter Table

t/h	0～0.5	0.5～1.0	1.0～1.5	1.5～2.0	2.0～2.5	2.5～3.0
							L(t)/kW	15	20	25	20	22	18

The data are substituted into the above equation, and optimization calculation is performed to obtain the output power of the electric working vehicle at different times, as shown in table 3 below, and the average output power P is 18.67kW, the minimum power deviation Δ P is 8kW, and the minimum electric quantity deviation Δ W is 4kW · h.

TABLE 3 discharge power curve parameter table for electric engineering vehicle

t/h	0～0.5	0.5～1.0	1.0～1.5	1.5～2.0	2.0～2.5	2.5～3.0
							P(t)/kW	15	20	20	20	19	18

After the operation is finished, the operation team returns, and as shown in fig. 8, the SOC condition of the storage battery of the electric engineering vehicle is obtained.

In this embodiment, a failure mode consequence analysis method is adopted, and the feasibility of the method is demonstrated by evaluating the influence of the electric engineering vehicle on the power supply reliability of the power distribution network of the power system. The invention adopts the fault rate lambda and the average fault duration r in the element reliability index and compares the annual user power failure frequency (ACI), the total user power failure duration time (CID), the average system power failure frequency (SAIFI), the average system power failure duration time (SAIDI) and the average power supply availability (ASAI) in the system reliability index.

In this embodiment, a typical structure, that is, a radial structure with single-end power supply, multiple segments, and a backup power supply is selected, AS shown in fig. 7, which is described by a load transfer probability in consideration of the load capacity of the backup power supply and is set to 0.5, where QF is a breaker, QS1, QS2, and QS3 are disconnectors, F1, F2, and F3 are fuses, left MS is a bus, and right AS is the backup power supply. Meanwhile, assuming that an SUV-type electric engineering vehicle is started, the battery capacity is selected to be 100 kW.h, the maximum discharge power can reach 30kW, the electric quantity is kept at least by 10%, and 80 kW.h can be reserved for discharging in consideration of the 10 kW.h consumption of the general starting task in driving.

In the present example, it is assumed that the average power consumption of the user load 1 is 0.5kW, the average power consumption of the load 2 is 1kW, and the average power consumption of the load 3 is 2 kW. During the power failure, the electricity power of common residential users is set to different values according to the difference of the number of users, but the total power value does not exceed the maximum power output by the electric engineering vehicle. The present embodiment considers only line faults, and the relevant reliability calculation parameters are shown in table 4.

TABLE 4 RELATED RELIABILITY CALCULATION PARAMETERS TABLE

Whether electric engineering vehicle power supply protection measures are added in the power distribution network or not is considered, all possible faults and the resulting consequences of the power distribution network power elements are listed and analyzed based on a fault mode consequence analysis method, for example: when a power supply trunk line fails for 2km, the bus breaker QF is disconnected, and the main power supply MS stops supplying power; then, an isolating switch QS1 is manually separated, the isolating switch QS3 is manually closed, a standby power supply AS is connected, the load 2 and the load 3 can recover power supply, the load 1 is in a power failure state until power is restored after fault processing and repairing are completed, and the power failure time is 3 hours. By analogy, all possible situations and the consequences thereof are listed, and through the power distribution network power supply reliability calculation process based on the failure mode consequence analysis method, the power supply reliability index difference of the existing or existing electric engineering vehicles is shown in the following table 5:

TABLE 5 comparison of power supply reliability indexes with and without electric engineering vehicle

Therefore, the power supply reliability of the power distribution network can be improved by adopting the method and the device.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.