Port microgrid coordination control method and system

Abstract

A port micro-grid coordination control method comprises the following steps: step 1, establishing four modes of micro-grid autonomy, active support, demand response and isolated grid operation of a port micro-grid, and establishing state transition boundary conditions of the four modes; 2, monitoring operation parameters of various resource devices of the port micro-grid in real time, and evaluating real-time adjustment potential values of the micro-grid and the various resource devices; 3, when the state meets a transition boundary condition, switching to a corresponding operation mode; and step 4, in the corresponding operation mode, performing optimization control on various devices in the port micro-grid.

Description

Technical Field

[0001] The present invention relates to the fields of power system automation and computers, and in particular to a port microgrid coordinated control method and system. Background Art

[0002] In recent years, power system construction has entered a new era. New energy, virtual power plants, new load control methods, and microgrids are key elements in the development of new power systems. Ports are a typical type of power load. With abundant distributed generation resources, unique power load terminals, and interactive energy storage production scenarios, ports are a key load type for new load management. The requirements for new power system construction require loads to be able to participate in flexible grid interaction and achieve coordination with the grid. As a typical load type, port microgrids require the establishment of a coordinated model for various resources to form a friendly interaction mechanism with the grid.

[0003] In this context, the present invention aims at the typical form of port load, establishes the port microgrid's autonomous, active support, demand response, isolated operation mode and automatic switching strategy, and supports the port microgrid's grid connection and coordinated interaction.

[0004] The prior art document (CN105591382A) discloses a network-source coordinated power control method for an isolated photovoltaic DC microgrid, which emphasizes the control process of internal devices of the photovoltaic DC microgrid and is unable to control the microgrid as a whole. Summary of the Invention

[0005] To address the technical challenges of coordinated interaction between port microgrids and power grids, this paper proposes a coordinated control strategy for port microgrids. This strategy categorizes the port microgrid's operating modes into four: autonomous, active support, demand response, and isolated operation. It also establishes boundary conditions and switching strategies for each mode. Furthermore, the control process considers photovoltaic, energy storage, and charging infrastructure, including control modes for heavy truck battery swapping and electric tugboats, optimizing the port microgrid's operational approach.

[0006] A first aspect of the present invention provides a coordinated control method for a port microgrid, comprising the following steps:

[0007] Step 1: Establish four modes for the port microgrid: autonomous, active support, demand response, and isolated grid operation. State assessment mechanisms and state transition boundary conditions for the four modes are also established. Under normal circumstances, the port microgrid is in autonomous operation. When voltage and frequency exceed limits, it switches to active support mode. When the grid initiates demand response, it switches to demand response mode. When the external grid switch is disconnected, it switches to isolated grid operation mode.

[0008] Step 2: Monitor the operating parameters of various resource devices in the port microgrid in real time, and evaluate the real-time regulation potential of the microgrid and various resource devices;

[0009] Step 3: When the state meets the transition boundary conditions, switch to the corresponding operation mode;

[0010] Step 4: Under the corresponding operating mode, optimize the control of various devices in the port microgrid.

[0011] Preferably, in step 1, if the microgrid receives an external real-time demand response instruction or an invitation demand response instruction, it is determined that the grid initiates the demand response.

[0012] Preferably, the regulation potentials to be evaluated for different devices in the microgrid in step 2 are as follows:

[0013] Evaluate the active and reactive regulation potential of photovoltaics, energy storage systems, and heavy truck battery swapping systems;

[0014] Charging piles, the electric tugboat charging system does not perform reactive power modulation, but only evaluates the active power regulation potential;

[0015] Preferably, the power control strategy in step 4 is as follows:

[0016] Step 4.1: Active voltage support strategy. Based on the grid voltage regulation requirements, the port microgrid is used for rapid regulation to support grid voltage stability. The control strategy prioritizes reactive power and then active power adjustment based on maximum power.

[0017] Step 4.2: Active frequency support strategy. Based on the grid frequency regulation requirements, the port microgrid is used for rapid regulation to support grid frequency stability. The control strategy adjusts active power according to the maximum power ranking.

[0018] Step 4.3, demand response control strategy, according to the grid initiates demand response to adjust the target value P total , using the port microgrid for active power regulation;

[0019] Step 4.4: Autonomous operation strategy: During peak and valley load times, the power supply demand is constrained and the main grid power supply load is minimized to ensure economical production operation.

[0020] Step 4.5, off-grid operation strategy: When an emergency such as external power outage occurs, the supercapacitor is immediately switched on, the non-guaranteed load switch is tripped, and the energy storage is switched to VF operation mode. As the main power supply of the microgrid, the photovoltaic power supply should be fully generated before being switched on, serving as the auxiliary power supply to ensure uninterrupted power supply to important loads, forming an off-grid operation mode.

[0021] Preferably, the voltage active support strategy in step 4.1 is specifically as follows:

[0022] When the voltage exceeds the limit, the reactive power regulation step ΔQ is set. In order to reduce the number of devices to be regulated, the reactive power regulation potential Q d Sort the devices from largest to smallest, giving priority to regulating devices with large reactive power potential;

[0023] If the voltage continues to exceed the limit, continue to adjust the reactive power of the microgrid with a step size of ΔQ until the reactive power regulation potential Q d The adjustment is completed; if the voltage reaches the qualified range during this process, stop, otherwise start adjusting the active power; set the active power adjustment step ΔP, and adjust the active power by the approaching adjustment method until the active power adjustment potential upper limit P is reached d Stop when

[0024] Preferably, the frequency active support strategy in step 4.2 is specifically as follows:

[0025] According to the frequency limit situation, calculate the adjustment target value P total , the active power demand is used as the total regulation target value to return to the frequency safety range after the frequency exceeds the limit, and the regulation target value is constrained by the microgrid regulation potential, P d =P total , if the regulation target value is greater than the regulation potential, then the regulation target value is equal to the maximum regulation potential of the microgrid;

[0026] Active power decomposition value P adji =P d *P coei , where P d is the total active power regulation potential value, P coei Normalized value of active power regulation potential of each device;

[0027] Control order result set numbers_P = sort(P adji ,descend), where descending order is performed according to the maximum power priority principle, the control order result set numbers_P is saved to the control order table, and control instructions are issued according to the sorting results.

[0028] Preferably, the demand response strategy in step 4.3 is specifically as follows:

[0029] Active power decomposition value P adji =P d *P coei , where P d is the total active power regulation potential value, P coei Normalized value of active power regulation potential of each device;

[0030] Control order result set numbers_P = sort((P adji ,Ki *P capi ),descend), where the maximum power is combined with the adjustment rate K i With the adjustment capacity P capi The product K i *P capi , sort in descending order. And save the control order result set numbers_P to the control order table;

[0031] Control instructions are issued in the order of the sorting results.

[0032] Preferably, the autonomous strategy at the peak load moment in step 4.4 is specifically as follows:

[0033] Photovoltaic power generation should be fully utilized without power adjustment; energy storage should be discharged to the lower limit of SOC; idle battery packs in heavy-duty truck battery swapping systems should be discharged to the lower limit of SOC; electric tugboats, heavy-duty truck battery swapping systems, and charging piles should not be subject to power adjustment.

[0034] Preferably, the autonomous strategy for the load valley moment in step 4.4 is as follows:

[0035] No power generation will be carried out during photovoltaic off-peak hours; energy storage will be charged to the upper limit of the SOC; the idle battery packs of the heavy-duty truck battery swap system will be charged to the upper limit of the SOC; no power adjustment will be performed on the electric tugboat, heavy-duty truck battery swap, or charging piles.

[0036] A second aspect of the present invention provides a port microgrid coordinated control system, which runs the above-mentioned port microgrid coordinated control method, including:

[0037] The mode establishment module is used to establish the four modes of the port microgrid: microgrid autonomy, active support, demand response, and isolated grid operation, as well as the state transition boundary conditions of the four modes;

[0038] The monitoring and evaluation module is used to monitor the operating parameters of various resource equipment in the port microgrid in real time, and to evaluate the status indicators of the microgrid and various resources in real time;

[0039] The mode switching module is used to switch the mode of various devices in the microgrid when they meet the mode change conditions;

[0040] The power control module is used to perform power decomposition control in different operating modes according to the regulation potential of the microgrid.

[0041] The beneficial effect of the present invention is that, compared with the existing technology, the present invention establishes four modes and a status evaluation mechanism for the port microgrid, realizes active switching of various modes based on evaluation indicators, and at the same time, in the coordinated control strategy, takes into account the port-specific heavy truck battery replacement and electric tugboat loads, thereby optimizing the operation mode of the port microgrid energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the four modes of microgrid changes;

[0043] Figure 2 It is a flow chart of the transition of microgrid operation modes;

[0044] Figure 3 It is a flow chart of the coordinated control method of the port microgrid;

[0045] Figure 4 It is a schematic diagram of the power decomposition process. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without making creative efforts are all within the scope of protection of the present invention.

[0047] The present invention provides a flow chart of a coordinated control method for a port microgrid, such as Figure 3 shown.

[0048] Step 4: Under the corresponding operating mode, optimize the control of various devices in the port microgrid.

[0049] Step 1: Establish four modes of port microgrid operation: microgrid autonomy, active support, demand response, and isolated grid operation, and establish the state transition boundary conditions of the four modes;

[0050] In a preferred but non-limiting embodiment of the present invention, step 1 specifically comprises:

[0051] Step 1.1: Establish four operation modes of the port microgrid, including: microgrid autonomy, active support, demand response, and isolated grid operation. Among them, microgrid autonomy means that when no external control commands are received and the grid connection point is in normal state, the microgrid will optimize the operation status of internal equipment according to the internal equipment resource status; the active support operation mode means that the microgrid actively detects the frequency and voltage changes of the grid connection point, and when the frequency and voltage are abnormal, it quickly starts the frequency support and voltage support control strategies to support the operation of the upper power grid; demand response means receiving the demand response command of the upper power grid, mobilizing internal resources, and responding to the control state of the target; isolated grid operation means the operation state when the external power grid encounters a fault and the microgrid is disconnected from the grid. The status changes of the four modes are as follows: Figure 1 shown.

[0052] Step 1.2: Establish the state transition conditions of the four modes and switch the operating mode by judging the microgrid operating state and transition boundary conditions.

[0053] The transition conditions are as follows: Under normal circumstances, the port microgrid is in an autonomous operation state. The operation of various energy sources in the port microgrid is coordinated through the autonomous operation strategy; at the same time, the voltage and frequency changes at the grid connection point are detected in real time. When the voltage and frequency exceed the limit, it actively switches to the active support operation mode; when the grid initiates a demand response, the port microgrid participates in the demand response, automatically adjusts the microgrid output within the specified time period, or accepts the real-time demand response adjustment of the grid. After the adjustment is completed, it returns to the autonomous operation state. During the operation of the microgrid, if the external power supply is detected to be lost, it switches to the isolated grid operation state. The overall flow chart is as follows Figure 2 shown.

[0054] Step 2: Based on step 1, monitor the operating parameters of various resource equipment in the port microgrid in real time, evaluate the status indicators of the microgrid and various resources in real time, and establish a real-time monitoring and evaluation indicator system for the port microgrid. Figure 4 As shown. Real-time monitoring of the operating parameters of the port microgrid and various resources, including grid connection point frequency f, grid connection point voltage U, microgrid demand response instructions S, active power P, reactive power Q, capacity, and status. The system also evaluates the real-time adjustment potential of the microgrid and various resources, whether they are controllable, and the operating mode. Whether they are controllable represents the controllability of each type of resource. The main judgment criteria include the constraints of the resource itself, as well as whether the communication is normal, whether it has remote control functions, and whether it is locked (locking is mainly caused by alarm information generated by the system. For example, when an alarm such as resource damage occurs, the resource will be locked and cannot be controlled; the lock will be automatically released after the alarm is resolved.)

[0055] The real-time regulation potential value is divided into real-time active regulation potential P d and real-time reactive power regulation potential Q d , which can be expressed by the following formula:

[0056]

[0057] Where: P di Indicates the active regulation potential of each type of equipment in the microgrid, Q di It represents the reactive power regulation potential of each type of equipment in the microgrid, and n represents the number of resources.

[0058] For each type of load, the power regulation potential P di , Q di The calculation is as follows:

[0059] 1) Photovoltaic system: According to the photovoltaic power generation status, photovoltaic active power, adjustable P diu = 0, P can be reduced did is the current power generation P pvi . Take a negative value relative to the load power.

[0060] Photovoltaic reactive power, according to the power factor of 0.9, the maximum reactive power and minimum reactive power range that can be provided, the reactive power increase potential Q pv_diu and reactive power reduction potential Q pv_did It can be expressed by the following formula:

[0061] Q pv_diu =Q dmaxi -Q di (3)

[0062] Q pv_did =Q dmini -Q di (4)

[0063] where Q dmaxi Indicates the maximum photovoltaic reactive power, Q di Indicates the current reactive power; Q dmini It is the minimum reactive power of photovoltaic power generation; it takes a negative value relative to the load power.

[0064] 2) Energy storage system: According to the energy storage operation status, when the energy storage is active, the active power increase potential P ess_diu and active power reduction potential P ess_did It can be expressed by the following formula:

[0065] P ess_diu =P stcmaxi -P sti (5)

[0066] P ess_did =P stemaxi -P sti (6)

[0067] Among them, P stcmaxi Indicates the maximum discharge power of energy storage, P sti Indicates the current active power; P stemaxi It is the maximum charging power of energy storage; relative to the load power, it takes a negative value.

[0068] When energy storage is reactive, the reactive power adjustment potential Q ess_diu and reactive power reduction potential Q ess_did It can be expressed by the following formula:

[0069] Q ess_diu =Q stcmaxi -Q sti (7)

[0070] Q ess_did =Q stemaxi -Q sti (8)

[0071] where Q stcmaxi Indicates the maximum reactive power of energy storage, Qsti Indicates the current reactive power; Q stemaxi It is the minimum reactive power of energy storage; relative to the load power, it takes a negative value.

[0072] Constraints on the operation of energy storage systems: SOC maxi >SOC i >SOC mini ,SOC maxi ,SOC mini They are the upper and lower limits of the energy storage system SOC, SOC i is the current SOC value.

[0073] 3) Charging pile equipment: Charging pile equipment is mainly for power load, which can be adjusted to increase P ev_diu k*(P polemaxi -P polei ), where P polemaxi is the maximum charging power of the charging pile, P polei Is the current charging power. Can be adjusted to reduce P ev_did P polei , that is, shut down the charging piles.

[0074] The controllable variable k indicates whether it is controllable. When k=1, it means it is controllable, and when k=0, it means it is uncontrollable.

[0075] Charging piles are similar to general power loads and do not perform reactive power regulation and control.

[0076] 4) Heavy-duty truck battery swap system: The main adjustable capacity of the heavy-duty truck battery swap system is composed of the battery pack in the battery swap station. Its potential calculation model is similar to that of the energy storage system. However, since the heavy-duty truck battery swap system is related to the port production process, adjusting the charging and discharging power will affect the business process. Therefore, the following calculation model is used for the heavy-duty truck battery swap system:

[0077] Active power increase potential: P diu =k1*P maxi , where P maxi Indicates the maximum discharge power of the battery pack at the battery swap station;

[0078] Active power reduction potential: P did =k1*P mini , where P mini Indicates the maximum charging power of the battery pack at the battery swap station; relative to the load power, it takes a negative value.

[0079] Reactive power increase potential: Q diu =k1*Q maxi , where Q maxi Indicates the maximum reactive power of the battery pack at the battery swap station;

[0080] Reactive power reduction potential: Q did =k1*Qmini , where Q mini Indicates the minimum reactive power of the battery pack in the battery swap station; relative to the load power, it takes a negative value.

[0081] k1 represents the number of idle battery packs.

[0082] 5) Electric tugboat charging system: The electric tugboat charging system mainly consists of an electric tugboat and a charging box. Its potential calculation model is similar to that of the charging pile system. However, since the electric tugboats in the port are related to the tidal regularity signal, the electric tugboats operate at high tide and can be charged at other times. Therefore, the following calculation model is used for the electric tugboat charging system:

[0083] Active power increase potential: P diu =k2*(P maxi -P polei ), where P maxi Indicates the maximum charging power of the electric tugboat charging system; P polei Indicates the current charging power.

[0084] Active power reduction potential: P did P polei , that is, shutting down the electric tugboat charging system.

[0085] k2 represents the tidal timing coefficient, which is 0 at high tide and 1 at charging time.

[0086] The electric tugboat charging system is similar to general electrical loads and does not perform reactive power regulation and control.

[0087] 6) General load equipment:

[0088] According to the operating status of the equipment, the power increase can be adjusted: P diu =k*(P avgmaxi -P polei ), where P polemaxi P is the average maximum power of general load equipment in the past 7 days. polei is the current load power, k is the adjustable coefficient, which is set to 1 if adjustable and 0 if not.

[0089] Adjustable power reduction: P diu =k*(P avgmini -P polei ), where P avgmini It is the average minimum power of general load equipment in the past 7 days.

[0090] Generally, reactive power regulation and control is not performed on load equipment.

[0091] Step 3: Based on the above steps 1 and 2, the microgrid real-time monitoring and index evaluation system is used to determine the microgrid mode transition boundary conditions. When the transition boundary conditions are met, the operation mode is switched to the corresponding operation mode. Mode switching includes:

[0092] Operation mode 1 indicates active support mode, monitoring the voltage U and frequency f of the microgrid connection point. When the voltage exceeds the limit, that is, U>U max Or U min When the frequency exceeds the limit, that is, f>f max or f <f min , enter the frequency support strategy.

[0093] Operation mode 2 indicates isolated grid operation mode, and the external power switch K s When the switch is disconnected, it indicates external power failure and enters the isolated grid operation strategy.

[0094] Operation mode 3 indicates demand response mode. When receiving external real-time demand response instructions or invitation demand response, the microgrid performs demand response regulation and control and enters the demand response strategy.

[0095] Operation mode 4 indicates the autonomous operation mode of the microgrid. When no external control command is received and the grid connection point is in normal state, the microgrid will optimize the operation status of the internal equipment according to the internal equipment resource status.

[0096] Step 4: Based on the formed microgrid regulation potential P d and Q d , power decomposition control is performed in different operating modes, the power decomposition process is as follows Figure 4 .

[0097] Step 4.1: Active voltage support strategy. Based on the grid voltage regulation requirements, the port microgrid is used for rapid regulation to support grid voltage stability. The control strategy prioritizes reactive power and then adjusts active power based on maximum power. The specific process is as follows:

[0098] a) When the voltage exceeds the limit, set the reactive power regulation step ΔQ. In order to reduce the number of equipment adjustments, according to the reactive power regulation potential Q d Sort the devices from largest to smallest, giving priority to regulating devices with large reactive power potential.

[0099] b) If the voltage continues to exceed the limit, continue to adjust the reactive power of the microgrid with a step size of ΔQ until the reactive power regulation potential Q d Adjustment is complete. If the voltage reaches the qualified range during this process, stop. Otherwise, go to c).

[0100] ​c) Start regulating active power, set the active power regulation step ΔP, use the approximate regulation method to regulate active power, and perform power decomposition control and distribution based on the maximum power priority principle until the voltage reaches the qualified range or reaches the upper limit of active power regulation potential P d Stop when

[0101] Step 4.2, the active frequency support strategy, uses the port microgrid to quickly adjust the frequency according to the grid frequency regulation requirements to support grid frequency stability. The control strategy adjusts active power according to the maximum power ranking. The specific process is as follows:

[0102] a) When the frequency exceeds the upper limit, calculate the adjustment target value P total , the total regulation target value for returning to the frequency safety range after the frequency exceeds the limit is reduced by the active power demand. When the frequency exceeds the lower limit, the total regulation target value for returning to the frequency safety range after the frequency exceeds the limit is increased by the active power demand. The regulation target value is constrained by the microgrid regulation potential, that is, P d =P total , if the regulation target value is greater than the regulation potential, then the regulation target value is equal to the maximum regulation potential of the microgrid.

[0103] b) Active power decomposition value P adji =P d *P coei , where P d is the total active power regulation potential value, P coei It is the normalized value of active power regulation potential of each device.

[0104] c) Control the order result set numbers_P = sort(P adji , descending), where the control order is sorted in descending order according to the principle of maximum power first. The control order result set, numbers_P, is saved to the control order table. Control instructions are issued based on the sorting results and written to memory.

[0105] Step 4.3, demand response control strategy, according to the grid initiates demand response to adjust the target value P total The target value is constrained by the microgrid regulation potential, and the port microgrid is used to regulate active power. The specific process is as follows:

[0106] a) Active power decomposition value P adji =P d *P coei , where P d is the total active power regulation potential value, P coei It is the normalized value of active power regulation potential of each device.

[0107] b) Control the order result set numbers_P = sort((P adji ,Ki *P capi ),descend), where the maximum power is combined with the adjustment rate K i With the adjustment capacity P capi The product K i *P capi , sort in descending order. And save the control order result set numbers_P to the control order table. The adjustment rate K of each device in the microgrid i It can be set according to engineering value experience. The adjustment rate range is 0-1, energy storage 1, photovoltaic 1, heavy truck battery replacement 1, charging pile 0.8, electric tugboat 0.2, and general load 0.1.

[0108] c) Issue control instructions according to the sorting results and write them into memory.

[0109] Step 4.4: Autonomous operation strategy, with meeting power supply demand as the constraint and minimizing main grid power load as the goal, to ensure economical production operation. In this mode, the control strategies of various microgrid resources are as follows:

[0110] Photovoltaic: During peak load periods, full power generation should be applied without power regulation. During low load periods, no power generation should be applied.

[0111] Electric tugboat: Charge and discharge according to production mode; no power adjustment.

[0112] Energy storage: When photovoltaic power generation is reversed, the energy storage is charged; when the load is low at night, the energy storage is charged. During daily electricity consumption, at peak load times, the energy storage is discharged to the lower limit of SOC, and at low load times, the energy storage is charged to the upper limit of SOC; therefore, the energy storage active power decomposition value P adji =K*P di , where P di The energy storage system issues control instructions based on different timings.

[0113] Heavy truck battery swap system: Combined with the port capacity, the idle battery pack can be adjusted for charging and discharging. During peak load periods, the idle battery pack is discharged to the lower limit of SOC; during low load periods, the idle battery pack is charged to the upper limit of SOC. Therefore, the active power decomposition value P of the heavy truck battery swap is adji =K*P di , where P di The energy storage system sends control instructions based on different timings and writes them into memory.

[0114] No power adjustment is performed for electric tugboats, heavy truck battery replacement, charging piles and general loads.

[0115] 5) Isolated grid operation strategy: When an emergency such as power failure in the external grid occurs, the system will automatically give a strategy. The supercapacitor will be immediately switched on and off, the non-guaranteed load switch will be tripped, and the energy storage will switch to VF operation mode. As the main power supply of the microgrid, photovoltaic power should be fully generated before switching on and off, and as an auxiliary power supply, it will ensure uninterrupted power supply to important loads and form an off-grid operation mode.

[0116] This paper primarily designs the operational states and state transition patterns of the port microgrid as a whole, emphasizing the regulation range of different modes rather than the control of internal devices. Based on the four operational states of the port microgrid as a whole, different state transition patterns are designed to measure the power regulation range in different states.

[0117] A second embodiment of the present invention discloses a port microgrid coordinated control system, which executes the port microgrid coordinated control method described in embodiment 1, including:

[0118] The mode establishment module is used to establish the four modes of the port microgrid: microgrid autonomy, active support, demand response, and isolated grid operation, as well as the state transition boundary conditions of the four modes;

[0119] The monitoring and evaluation module is used to monitor the operating parameters of various resource equipment in the port microgrid in real time, and to evaluate the status indicators of the microgrid and various resources in real time;

[0120] The mode switching module is used to switch the mode when the microgrid meets the mode transition conditions;

[0121] The power control module is used to perform power decomposition control in different operating modes according to the regulation potential of the microgrid.

[0122] The above steps are explained with examples, and the operation of each mode is described in detail:

[0123] For example, the port's adjustable resources include a photovoltaic capacity of 100kW, with a current active power of 60kW; reactive power upper and lower limits of ±50kvar, and a current reactive power of 0kvar.

[0124] Energy storage capacity is 8000kWh, rated active power is 4000kW, current active power is 1000kW; reactive power upper and lower limits are ±2000kvar, current reactive power is 0kvar; energy storage SOC upper limit is 90%, lower limit is 20%, current SOC is 90%.

[0125] The heavy-duty truck has a battery swap capacity of 4000kWh, a rated active power of 800kW, 8 battery packs, a current active power of 200kW, and two battery packs are charging; the upper and lower limits of reactive power are ±400kvar, and the current reactive power is 0kvar.

[0126] The charging pile capacity is 500kW and the current active power is 300kW.

[0127] The electric tugboat charging system has a capacity of 2000kW. It is currently non-high tide period and the current active power is 1000kW.

[0128] The general load capacity is 2000kW, and the current power is 1200kW; the average maximum power in the past 7 days is 1600kW, and the average minimum power is 900kW.

[0129] According to the above process, the adjustable potential of microgrid and various resources is calculated as follows:

[0130] Photovoltaic: Active power, adjustable P diu =0kW; adjustable P did =60kW; reactive power, adjustable Q diu =50kvar; adjustable Q did =50kvar.

[0131] Energy storage: active power, adjustable P diu =3000kW; adjustable P did =5000kW; reactive power, adjustable Q diu =2000kvar; adjustable Q did =2000kvar.

[0132] Heavy truck battery replacement: active power, adjustable P diu =600kW; adjustable P did =600kW; reactive power, adjustable Q diu =400kvar; adjustable Q did =400kvar.

[0133] Charging pile: active power, adjustable P diu =200kW; adjustable P did =300kW.

[0134] Electric tugboat: active power, adjustable P diu =1000kW; adjustable P did =1000kW.

[0135] General load: active power, adjustable P diu =400kW; adjustable P did =300kW.

[0136] Microgrid: Active power, adjustable P diu =5200kW; adjustable P did =7260kW; reactive power, adjustable Qdiu =2450kvar; adjustable Q did =2450kvar.

[0137] Then the mode is judged. When the state meets the transition boundary conditions, it switches to the corresponding operation mode. And according to the potential P of the microgrid and various resources formed, d and Q d , perform power decomposition control under different strategies. For example:

[0138] Active voltage support strategy: When the voltage exceeds the limit, the reactive power is adjusted in 100kW steps until Q d = 2450kvar. Then, the active power is adjusted in steps of 100kW, and power decomposition control is performed based on the principle of maximum power priority until the voltage reaches the qualified range.

[0139] Active frequency support strategy: When the frequency exceeds the upper limit, the active power demand is reduced by 8000kW as the total regulation target value to return to the frequency safety range after the frequency exceeds the limit. The regulation target value is constrained by the microgrid regulation potential. If the current regulation target value is greater than the regulation potential, the regulation target value is equal to the maximum regulation potential of the microgrid, that is, P d = 7260kW. Power was distributed and controlled based on the principle of maximum power priority, reducing energy storage active power by 5000kW, electric tugboat active power by 1000kW, heavy truck battery swap active power by 600kW, charging pile active power by 300kW, general load active power by 300kW, and photovoltaic active power by 60kW. The return result indicated that the adjustment target was not achieved.

[0140] When the frequency exceeds the lower limit, the active power demand is increased by 2250kvar as the total regulation target value to return to the frequency safety range after the frequency exceeds the limit. The regulation target value is constrained by the microgrid regulation potential, that is, Q d =2250kvar. Power decomposition control is implemented based on the principle of maximum power priority, reducing energy storage reactive power by 2000kvar, heavy truck battery replacement reactive power by 250kvar, and photovoltaic reactive power without adjustment.

[0141] Isolated grid operation strategy: External grid switch status K s Disconnect, the system immediately switches to the isolated grid operation mode, the system automatically gives a strategy, adjusts the energy storage supercapacitor to switch immediately, adjusts the non-guaranteed load switches K1, K2, K3, K n When the power is tripped, the energy storage switches to the VF operation mode. As the main power supply of the microgrid, photovoltaic power should be fully utilized, and as the auxiliary power supply, it can ensure uninterrupted power supply to important loads and form an off-grid operation mode.

[0142] Demand response strategy: Receive the demand response command from the upper power grid, reduce the active power by 7000kW, and adjust the target value based on the microgrid regulation potential, that is, P d =7000kW. The control order is numbers_P=sort((P adji ,K i *P capi ),descend) formula calculation results are used to perform power decomposition control and delivery, where the maximum power is combined with the adjustment rate K i *Regulating capacity P capi Sort by descending order, where the adjustment rate K of each resource in the microgrid is i Based on engineering experience, the control order and values are: energy storage 1, photovoltaic 1, heavy truck battery swap 1, charging pile 0.8, electric tugboat 0.2, and general load 0.1. Using the above formula, the control order and values are: energy storage 5000kW, heavy truck battery swap 600kW, electric tugboat 1000kW, charging pile 300kW, general load 100kW, and no photovoltaic control.

[0143] Microgrid autonomous operation strategy: Based on the constraints of meeting power supply demand, the goal is to minimize the main grid power supply load and reduce the peak-to-valley difference to ensure economical production operation. In this mode, the various resource control strategies of the microgrid are as follows:

[0144] During peak load periods, PV power generation should be maximized; no power regulation is performed. Energy storage: Energy storage is discharged at 2000kW / h to the lower SOC limit, which can support 2.8 hours of peak load. Heavy-duty truck battery swapping system: Idle battery packs are discharged at 600kW / h to the lower SOC limit, which can support 5 hours of peak load. No power regulation is performed for electric tugboats, heavy-duty truck battery swapping, charging stations, and general loads.

[0145] During low-load periods, energy storage is used: Energy storage is discharged to the lower SOC limit during peak load periods. Therefore, energy storage is charged at 2000kW / h to the upper SOC limit, which can support a 2.8-hour low-load period. Heavy-duty truck battery swapping systems: Idle battery packs are charged at 600kW / h to the upper SOC limit, which can support a 5-hour low-load period. No photovoltaic power generation occurs during low-load periods. No power regulation is performed for electric tugboats, heavy-duty truck battery swapping, charging stations, and general loads.

[0146] The present disclosure may be a system, method and / or computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A coordinated control method for a port microgrid, characterized in that: include: Four modes of operation are established for the port microgrid: autonomous operation, active support, demand response, and isolated operation. State transition boundary conditions for the four modes are also established. Under normal circumstances, the port microgrid is in autonomous operation. When voltage and frequency exceed the limit, it switches to active support operation mode. When the grid initiates demand response, it switches to demand response mode. When the external grid switch is disconnected, it switches to isolated operation mode. Real-time monitoring of the operating parameters of various resource equipment in the port microgrid, and evaluation of the real-time adjustment potential of the microgrid and various resource equipment; When the microgrid operating state meets the transition boundary conditions, it switches to the corresponding operating mode; Under the corresponding operating mode, the power of various equipment in the port microgrid is controlled.

2. A coordinated control method for a port microgrid according to claim 1, characterized in that: If the microgrid receives an external real-time demand response instruction or an invitation demand response instruction, it is determined that the grid initiates the demand response.

3. A coordinated control method for a port microgrid according to claim 1, characterized in that: Evaluation of the real-time regulation potential of microgrids and various resource devices includes: Evaluate the active and reactive regulation potential of photovoltaics, energy storage systems, and heavy truck battery swapping systems; Charging piles, electric tugboat charging systems and no reactive power modulation are performed, only active power regulation potential is evaluated.

4. A coordinated control method for a port microgrid according to claim 1, characterized in that: Control the power of various devices in the port microgrid, including: Active voltage support strategy: Based on the grid voltage regulation requirements, the port microgrid is used to adjust the voltage to support grid voltage stability. The control strategy prioritizes reactive power and then adjusts active power according to the maximum power. Active frequency support strategy: Based on the grid frequency regulation requirements, the port microgrid is used to adjust the frequency to support grid frequency stability. The control strategy adjusts active power according to the maximum power ranking. Demand response control strategy, based on the grid-initiated demand response, adjusts the target value P total , using the port microgrid for active power regulation; Autonomous operation strategy, during peak load and low load periods, is based on meeting power supply demand and aims to minimize main grid power supply load; Off-grid operation strategy: when an emergency such as power failure in the external power grid occurs, the supercapacitor is immediately switched on and off, the non-guaranteed load switch is tripped, and the energy storage is switched to VF operation mode. As the main power supply of the microgrid, photovoltaic power should be fully generated before being switched on and off, serving as an auxiliary power supply to ensure uninterrupted power supply to important loads, forming an off-grid operation mode.

5. A coordinated control method for a port microgrid according to claim 3, characterized in that: Active voltage support strategies include: When the voltage exceeds the limit, the reactive power regulation step ΔQ is set. In order to reduce the number of devices to be regulated, the reactive power regulation potential Q d Sort the devices from largest to smallest, giving priority to regulating devices with large reactive power potential; If the voltage continues to exceed the limit, continue to adjust the reactive power of the microgrid with a step size of ΔQ until the reactive power regulation potential Q d The adjustment is completed; if the voltage reaches the qualified range during this process, stop, otherwise start adjusting the active power; set the active power adjustment step ΔP, and adjust the active power by the approaching adjustment method until the active power adjustment potential upper limit P is reached d Stop when 6. A coordinated control method for a port microgrid according to claim 3, characterized in that: Frequency active support strategies include: According to the frequency limit situation, calculate the adjustment target value P total , the active power demand is used as the total regulation target value to return to the frequency safety range after the frequency exceeds the limit, and the regulation target value is constrained by the microgrid regulation potential, P d =P total , if the regulation target value is greater than the regulation potential, then the regulation target value is equal to the maximum regulation potential of the microgrid; Active power decomposition value P adji =P d *P coei , where P d is the total active power regulation potential value, P coei Normalized value of active power regulation potential of each device; Control order result set numbers_P = sort(P adji ,descend), where descending order is performed according to the maximum power priority principle, the control order result set numbers_P is saved to the control order table, and control instructions are issued according to the sorting results.

7. A coordinated control method for a port microgrid according to claim 3, characterized in that: Demand response strategies include: Active power decomposition value P adji =P d *P coei , where P d is the total active power regulation potential value, P coei Normalized value of active power regulation potential of each device; Control order result set numbers_P = sort((P adji ,K i *P capi ),descend), where the maximum power is combined with the adjustment rate K i With the adjustment capacity P capi The product K i *P capi , sort in descending order. And save the control order result set numbers_P to the control order table; Control instructions are issued in the order of the sorting results.

8. A coordinated control method for a port microgrid according to claim 3, characterized in that: Autonomous strategies for peak load periods include: Photovoltaic power generation should be fully utilized without power adjustment; energy storage should be discharged to the lower limit of SOC; idle battery packs in heavy-duty truck battery swapping systems should be discharged to the lower limit of SOC; electric tugboats, heavy-duty truck battery swapping systems, and charging piles should not be subject to power adjustment.

9. A coordinated control method for a port microgrid according to claim 8, characterized in that: Autonomous strategies for low-load periods include: No power generation will be carried out during photovoltaic off-peak hours; energy storage will be charged to the upper limit of the SOC; the idle battery packs of the heavy-duty truck battery swap system will be charged to the upper limit of the SOC; no power adjustment will be performed on the electric tugboat, heavy-duty truck battery swap, or charging piles.

10. A port microgrid coordinated control system, running a port microgrid coordinated control method according to any one of claims 1 to 9, characterized in that: include: The mode establishment module is used to establish the four modes of the port microgrid: microgrid autonomy, active support, demand response, and isolated grid operation, as well as the state transition boundary conditions of the four modes; The monitoring and evaluation module is used to monitor the operating parameters of various resource equipment in the port microgrid in real time, and to evaluate the status indicators of the microgrid and various resources in real time; The mode switching module is used to switch the mode of various devices in the microgrid when they meet the mode change conditions; The power control module is used to perform power decomposition control in different operating modes according to the regulation potential of the microgrid.

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