Seamless transfer control method, system and device for access of multiple emergency power supply vehicles to power distribution network and storage medium

Abstract

The invention discloses a seamless transfer control method, system and device for multiple emergency power supply vehicles to access a power distribution network and a storage medium, and the method comprises the steps: enabling each emergency power supply vehicle to output power proportionally according to the own capacity under the condition that the multiple emergency power supply vehicles operate in parallel and access through a voltage control method based on a virtual impedance method; through a synchronous control method based on bus voltage tracking, synchronous control of each emergency power supply vehicle in a commercial power supply mode and an emergency power supply vehicle power supply mode is realized, and pre-synchronous control of switching the emergency power supply vehicle access mode and the emergency power supply vehicle power supply mode into the commercial power supply mode is realized. Combined power supply and switching of multiple emergency power supply vehicles can be safely, reliably, flexibly and efficiently controlled, and emergency power protection work such as user zero-perception non-power-cut maintenance or temporary power supply is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-stop operation of low-voltage distribution networks, and in particular to a seamless power transfer control method, system, device and storage medium for connecting multiple emergency power supply vehicles to a distribution network. Background Art

[0002] With the rapid development of social economy and the continuous improvement of people's living standards, users have higher and higher requirements for power supply reliability. To improve power supply reliability, it is necessary to reduce power outages, and carrying out power distribution without power outages is the most direct and effective measure to improve power supply reliability.

[0003] In the process of non-stop power distribution operations, the use of emergency power supply vehicles to carry out load operations can fully meet the non-stop power distribution network operations, emergency power supply guarantees, and temporary capacity expansion of the distribution network, becoming one of the important technical means to further improve power supply reliability. However, when the emergency power supply vehicle is connected to or exits the user-side busbar, it is likely to force the user to experience multiple short-term power outages. The overall application process presents a "late-coming, passive limitation" characteristic, which reduces the access efficiency and violates the meaning of power protection; at the same time, for substations with large-capacity loads, a single emergency power supply vehicle will not be able to meet the power supply needs. In summary, there is an urgent need for a seamless power transfer control method, system, device and storage medium for multiple emergency power supply vehicles to access the distribution network.

[0004] The patent with the authorization announcement number CN116742787B in the prior art document discloses a non-stop switching control method and system for the access of an emergency power supply vehicle to a distribution network. The method verifies the remote control operation instructions for the opening and closing of the grid-side circuit breaker QF1 and the emergency power supply side circuit breaker QF2. If the remote control operation instruction causes a power outage in the load branch, the corresponding remote control operation is locked; the synchronous grid connection conditions are judged for the closing remote control operation instruction of the circuit breaker, and the closing operation of the circuit breaker is executed when the conditions are met; after the successful closing of QF1 or QF2, the corresponding emergency power supply vehicle power adjustment control instruction is triggered, and after a preset delay, the opening remote control instruction of the circuit breaker on the other side is triggered. After the opening remote control operation instruction is verified, the corresponding opening remote control operation is executed to realize the automatic switching control between the emergency power supply vehicle and the power grid without power outage. However, it is aimed at the access control scenario of a single emergency power supply vehicle, and cannot be applied to the joint access control of multiple emergency power supply vehicles, let alone the power control of each of the multiple emergency power supply vehicles. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a seamless power transfer control method, system, device and storage medium for connecting multiple emergency power supply vehicles to a distribution network. Without human intervention, it can automatically control the activation and deactivation of multiple emergency power supply vehicles safely, reliably, flexibly and efficiently, and coordinate the control of each emergency power supply vehicle to output power in proportion to its own capacity, thereby realizing emergency power supply maintenance or temporary power supply without user perception.

[0006] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0007] The first aspect of the present invention provides a seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network, comprising:

[0008] Through the voltage control method based on the virtual impedance method, the virtual impedance is adjusted to control multiple emergency power supply vehicles to output power in proportion to their own capacity when they are connected to the distribution network in parallel;

[0009] Through the synchronous control method based on bus voltage tracking, each emergency power supply vehicle that has adjusted its virtual impedance to control its output power in proportion is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when the emergency power supply vehicle is in access mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode, so that the voltage of each emergency power supply vehicle always tracks the bus voltage, which is used to seamlessly convert the mains power to each emergency power supply vehicle or multiple emergency power supply vehicles to the mains power supply.

[0010] Preferably, a voltage control method based on the virtual impedance method is used to control multiple emergency power supply vehicles to output power in proportion to their own capacity when they are connected to the distribution network in parallel operation by adjusting the virtual impedance. Specifically, the emergency power supply vehicle is set to the voltage source control mode in both the mains power supply mode and the emergency power supply vehicle power supply mode, and the no-load output voltage of each emergency power supply vehicle is controlled to be equal. The virtual impedance R of each emergency power supply vehicle is set to the same value. i Make settings so that each emergency power supply vehicle can output power in proportion to its own capacity.

[0011] Preferably, the active power P output by the i-th emergency power supply vehicle when it is connected to the distribution network is i and reactive power Q i The calculation formula is:

[0012]

[0013] Where, U0 is the effective value of bus voltage; U i is the effective value of the no-load output voltage of the i-th emergency power supply vehicle; R i is the virtual impedance between the i-th emergency power supply vehicle and the bus; Output voltage phase of the i-th emergency power supply vehicle;

[0014] No-load output voltage U of each emergency power supply vehicle i Equal to the collected AC bus voltage U0, when the output voltage phase of each emergency power supply vehicle is When the active power P of each emergency power supply vehicle is equal, i and reactive power Q i Both with virtual impedance R i The virtual impedance is inversely proportional to the capacity and power ratio of each emergency power supply vehicle.

[0015] Preferably, the synchronous control method based on bus voltage tracking performs synchronous control on each emergency power supply vehicle in the mains power supply mode and the emergency power supply vehicle power supply mode, specifically:

[0016] Construct a virtual bus voltage;

[0017] In the mains power supply mode, the bus voltage and virtual bus voltage are provided by the main grid, and each emergency power supply vehicle tracks the virtual bus voltage to output the specified reactive power to achieve synchronous control;

[0018] In the emergency power supply vehicle power supply mode, the bus voltage and the virtual bus voltage are jointly generated by each emergency power supply vehicle. The emergency power supply vehicle tracks the virtual bus voltage to achieve synchronous control. Among them, the voltage phase difference between the emergency power supply vehicle and the bus and the reactive power output of the emergency power supply vehicle are determined by the load.

[0019] Preferably, through a synchronous control method based on bus voltage tracking, each emergency power supply vehicle is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when the emergency power supply vehicle is connected to the mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode; specifically, step 1, assuming that the initial phase angle of the output voltage of each emergency power supply vehicle is

[0020] Step 2, wait for the interruption. After the interruption is satisfied, check whether the emergency power supply vehicle i has received the pre-synchronization instruction. If the pre-synchronization instruction is not received, it is determined that it is in the mains power supply mode or the emergency power supply vehicle power supply mode at this time, and step 3 is executed; otherwise, it is determined that it is in the emergency power supply vehicle access mode or the emergency power supply vehicle power supply mode is switched to the mains power supply mode, and step 4 is executed;

[0021] Step 3, construct the virtual bus voltage, execute the set synchronization algorithm, each emergency power supply vehicle tracks the virtual bus voltage phase, realizes synchronization control, and returns to step 2;

[0022] Step 4: Set the grid voltage to the synchronous voltage, start pre-synchronization control, and calculate the iterative angle difference between the tth interruption and the t+1th interruption and Determine whether it is satisfied ε sets the threshold value. If yes, the pre-synchronization is completed and step 5 is executed. Otherwise, it returns to step 2.

[0023] Step 5: Determine whether the emergency power supply vehicle is connected. If so, close the corresponding emergency power supply vehicle interface switch, switch the synchronous voltage to the bus voltage, end the pre-synchronization instruction, and return to step 2; otherwise, close the grid-connected switch, and after completion, disconnect all emergency power supply vehicle interface switches to end the control.

[0024] Among them, the emergency power supply vehicle interface switch is a switch between the emergency power supply vehicle and the distribution network. When closed, the power supply vehicle is connected to the distribution network; the grid-connected switch is a switch between the mains power and the distribution network. When closed, the mains power is connected to the distribution network.

[0025] Preferably, in step 3, the virtual bus voltage is specifically: the amplitude of the virtual bus voltage is set to be equal to the bus voltage amplitude, and the phase of the virtual bus voltage is set to be the leading bus voltage phase Virtual Phase Difference It is equal to the phase difference between the output voltage of the emergency power supply vehicle and the bus voltage set in the case of grid connection, and the virtual bus voltage It is expressed by the following formula:

[0026]

[0027] Where: U0 is the effective value of bus voltage; is the bus voltage phase angle; virtual phase difference The reactive power command value Q * Determine, the formula is:

[0028]

[0029] Among them, R i is the virtual impedance between the i-th emergency power supply vehicle and the busbar, U i is the effective value of the no-load output voltage of the i-th emergency power supply vehicle.

[0030] Preferably, each emergency power supply vehicle in step 3 tracks the virtual bus voltage phase to achieve synchronous control, and its control expression is:

[0031]

[0032] in:

[0033]

[0034] Where: is the voltage phase of the emergency power supply vehicle i when it is interrupted for the tth time, To control the voltage phase of emergency power supply vehicle i when it is interrupted for the t+1th time, k is the proportional coefficient, f0 is the fundamental frequency, and T is the interruption period.

[0035] Preferably, the pre-synchronization control and synchronization control in step 4 use the same control expression:

[0036] The second aspect of the present invention provides a seamless power transfer control system for connecting multiple emergency power supply vehicles to a power distribution network, which is used to implement the method described in the first aspect of the present invention, including:

[0037] Through the voltage control module based on the virtual impedance method, the virtual impedance is adjusted to control multiple emergency power supply vehicles to output power in proportion to their own capacity when they are connected to the distribution network in parallel;

[0038] Through the synchronization module based on bus voltage tracking, each emergency power supply vehicle that has adjusted its virtual impedance to control its output power in proportion is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when it is in the emergency power supply vehicle access mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode, so that the voltage of each emergency power supply vehicle always tracks the bus voltage, which is used to seamlessly convert the mains power to each emergency power supply vehicle or multiple emergency power supply vehicles to the mains power supply.

[0039] The third aspect of the present invention provides a seamless power transfer control device for connecting multiple emergency power supply vehicles to a power distribution network, including a processor and a storage medium:

[0040] The storage medium is used to store instructions;

[0041] The processor is used to operate according to the instructions to execute the method described in the second aspect of the present invention.

[0042] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the second aspect of the present invention.

[0043] The beneficial effects of the present invention are as follows:

[0044] (1) The present invention realizes power decoupling by using a voltage control method based on a virtual impedance method and utilizing equivalent impedance to simulate the effect of actual physical impedance. The power ratio of each emergency power supply vehicle can be dynamically adjusted in a scenario where multiple emergency power supply vehicles are connected in parallel.

[0045] (2) Through the synchronous control method based on bus voltage tracking, the synchronous control of each emergency power supply vehicle in the mains power supply mode and the emergency power supply vehicle power supply mode, as well as the pre-synchronous control of the emergency power supply vehicle access mode and the emergency power supply vehicle power supply mode switching to the mains power supply mode can be achieved.

[0046] (3) In both the mains power supply mode and the emergency power supply vehicle power supply mode, all emergency power supply vehicles always collect virtual bus voltage phase information for synchronous control, and the synchronous control and pre-synchronous control use the same control algorithm, without the need to switch control strategies; it can safely, reliably, flexibly and efficiently control the joint power supply and withdrawal of multiple emergency power supply vehicles, realizing zero-perception, non-stop maintenance or temporary power supply and other emergency power supply operations for users.

[0047] (4) Each emergency power supply vehicle has an equal status, and the shutdown of any emergency power supply vehicle will not affect the normal operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a seamless power transfer control flow chart of multiple emergency power supply vehicles connected to a power distribution network of the present invention;

[0049] Figure 2 It is a schematic diagram of the topological structure of multiple emergency power supply vehicles connected to the power distribution network of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the 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 creative work are all within the scope of protection of the present invention.

[0051] like Figure 1 As shown, embodiment 1 of the present invention provides a seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network, such as Figure 2 Taking the topology structure shown in the figure and the connection scenario of two emergency power supply vehicles as an example, the method includes the following steps:

[0052] Through the voltage control method based on the virtual impedance method, the virtual impedance is adjusted to control multiple emergency power supply vehicles to output power in proportion to their own capacity when they are connected to the distribution network in parallel;

[0053] Preferably, the voltage control based on the virtual impedance method sets the emergency power supply vehicle to the voltage source control mode in both the mains power supply mode and the emergency power supply vehicle power supply mode, controls the no-load output voltage of each emergency power supply vehicle to be equal, and sets the virtual impedance R of each emergency power supply vehicle to the same value. i Make settings so that each emergency power supply vehicle can output power in proportion to its own capacity.

[0054] Preferably, the voltage control method based on the virtual impedance method is used to control multiple emergency power supply vehicles to output power in proportion to their own capacity when connected in parallel. The specific scheme is:

[0055] The active power P output when the i-th emergency power supply vehicle is connected to the distribution network i and reactive power Q i The calculation formula is:

[0056]

[0057] Where: U0 is the effective value of bus voltage; U i is the effective value of the no-load output voltage of the i-th emergency power supply vehicle; R i is the virtual impedance between the i-th emergency power supply vehicle and the bus; Output voltage phase of the i-th emergency power supply vehicle;

[0058] No-load output voltage U of each emergency power supply vehicle i Equal to the collected AC bus voltage U0, when the output voltage phase of each emergency power supply vehicle is When the active power P of each emergency power supply vehicle is equal, i and reactive power Q i Both with virtual impedance R i The equivalent impedance is set inversely proportional to the capacity and power ratio of each emergency power supply vehicle. Specifically, the capacity ratio of the two emergency power supply vehicles is 2:1, and the virtual impedance connected to the two emergency power supply vehicles is set to R1:R2=1:2. According to the above formula, P1:P2=2:1; similarly, if it is guaranteed at this time Then Q1:Q2=2:1.

[0059] Through the synchronous control method based on bus voltage tracking, each emergency power supply vehicle that has adjusted its virtual impedance to control its output power in proportion is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when the emergency power supply vehicle is in access mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode, so that the voltage of each emergency power supply vehicle always tracks the bus voltage, which is used to seamlessly convert the mains power to each emergency power supply vehicle or multiple emergency power supply vehicles to the mains power supply.

[0060] Preferably, the synchronous control method based on bus voltage tracking performs synchronous control on each emergency power supply vehicle in the mains power supply mode and the emergency power supply vehicle power supply mode, specifically: constructing a virtual bus voltage. In the mains power supply mode, the bus voltage and the virtual bus voltage are provided by the main grid. At this time, the synchronous control is that each emergency power supply vehicle tracks the virtual bus voltage, thereby outputting a specified reactive power; while in the emergency power supply vehicle power supply mode, the bus voltage and the virtual bus voltage are jointly generated by each emergency power supply vehicle. Although the emergency power supply vehicle is still tracking the virtual bus voltage at this time, the voltage phase difference between the emergency power supply vehicle and the bus and the reactive power output by the emergency power supply vehicle are determined by the load.

[0061] Preferably, through a synchronous control method based on bus voltage tracking, each emergency power supply vehicle is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when the emergency power supply vehicle is connected to the mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode; specifically:

[0062] Step 1: Assume that the initial phase angle of the output voltage of each emergency power supply vehicle is

[0063] Specifically, connect two emergency power supply vehicles to Figure 2 The emergency power supply vehicle interface shown in the figure, at this time, the circuit breakers QF1 and QF2 are both in the closed state, and the switches at the interfaces of each emergency power supply vehicle are in the open state; start each emergency power supply vehicle and set it to the voltage source control mode, and set the initial phase angle to

[0064] Step 2, wait for the interruption. After the interruption is satisfied, check whether the emergency power supply vehicle i has received the pre-synchronization instruction. If the pre-synchronization instruction is not received, it is determined that it is in the mains power supply mode or the emergency power supply vehicle power supply mode at this time, and step 3 is executed; otherwise, it is determined that it is in the emergency power supply vehicle access mode or the emergency power supply vehicle power supply mode is switched to the mains power supply mode, and step 4 is executed;

[0065] Specifically, a pre-synchronization control instruction of the emergency power supply vehicle access mode is triggered, and step 4 is executed after receiving the pre-synchronization control instruction.

[0066] Step 3, construct the virtual bus voltage, execute the set synchronization algorithm, each emergency power supply vehicle tracks the virtual bus voltage phase, realizes synchronous control, and returns to step 2.

[0067] Preferably, the virtual bus voltage in step 3 is specifically as follows: construct a virtual bus voltage, the amplitude of the virtual bus voltage is set to be equal to the bus voltage amplitude, and the phase of the virtual bus voltage is set to be the leading bus voltage phase Virtual Phase Difference It is equal to the phase difference between the output voltage of the emergency power supply vehicle and the bus voltage set in the case of grid connection, and the virtual bus voltage It is expressed by the following formula:

[0068]

[0069] Where: U0 is the effective value of bus voltage; is the bus voltage phase angle; virtual phase difference The reactive power command value Q * Determine, the formula is:

[0070]

[0071] Among them, R i is the virtual impedance between the i-th emergency power supply vehicle and the busbar, U i is the effective value of the no-load output voltage of the i-th emergency power supply vehicle.

[0072] Preferably, each emergency power supply vehicle in step 3 tracks the virtual bus voltage phase to achieve synchronous control, and its control expression is:

[0073]

[0074] in:

[0075]

[0076] Where: is the voltage phase of the emergency power supply vehicle i when it is interrupted for the tth time, To control the voltage phase of emergency power supply vehicle i when it is interrupted for the t+1th time, k is the proportional coefficient, f0 is the fundamental frequency, and T is the interruption period.

[0077] Step 4: Set the grid voltage to the synchronous voltage, start pre-synchronization control, and calculate the iterative angle difference between the tth interruption and the t+1th interruption and Determine whether it is satisfied Where ε is the set threshold. If yes, the pre-synchronization is completed and step 5 is executed. Otherwise, return to step 2.

[0078] Specifically, ε is set to 10 -5 .

[0079] Preferably, the pre-synchronization control and synchronization control in step 4 use the same control expression.

[0080] Specifically, the grid voltage (at sampling point 1) is set as the synchronization voltage to perform pre-synchronization control; after the pre-synchronization is completed (i.e. )Go to step 5;

[0081] Step 5, determine whether the emergency power supply vehicle is connected. If so, close the corresponding emergency power supply vehicle interface switch, switch the synchronous voltage to the bus voltage, end the pre-synchronization instruction at the same time, and return to step 2; otherwise, close the grid-connected switch, and after completion, disconnect all emergency power supply vehicle interface switches to end the control, wherein the emergency power supply vehicle interface switch is the switch between the emergency power supply vehicle and the distribution network. When closed, the power supply vehicle is connected to the distribution network; the grid-connected switch is the switch between the mains and the distribution network. When closed, the mains is connected to the distribution network.

[0082] Specifically, it is determined that the emergency power supply vehicle is connected, the corresponding emergency power supply vehicle interface switch is closed, the synchronous voltage is switched to the bus voltage (at sampling point 2), and the pre-synchronization instruction is terminated at the same time, and the process returns to step 2. After the interruption is satisfied, if no pre-synchronization instruction is received, 2.3 synchronization control is performed. After waiting for all emergency power supply vehicle interface switches to be closed, the grid-connected switch (circuit breaker QF1) is opened to switch to the emergency power supply vehicle power supply mode;

[0083] The above completes the access process of the emergency power supply vehicle and completes the switching from the mains power supply mode to the emergency power supply vehicle power supply mode. During this period, the pre-synchronization control of switching the access mode of each emergency power supply vehicle to the mains power supply mode and the synchronization control of each emergency power supply vehicle in the mains power supply mode and the emergency power supply vehicle power supply mode are realized.

[0084] After the maintenance work or the main network fault is eliminated, the pre-synchronization control instruction is triggered to switch the power supply mode of the emergency power supply vehicle to the mains power supply mode, and then go to step 4.

[0085] Specifically, at this time, QF1 is in the disconnected state, and the grid voltage (at sampling point 1) is set to the synchronous voltage to perform pre-synchronization control; after waiting for all emergency power supply vehicles to complete pre-synchronization (i.e. ) and go to step 5.

[0086] Specifically, it is determined that the emergency power supply vehicle is not connected at this moment, and the grid-connected switch (circuit breaker QF1) is closed. After completion, all emergency power supply vehicle interface switches are disconnected. The above completes the process of disconnecting and connecting the emergency power supply vehicle, and completes the switching from the emergency power supply vehicle power supply mode to the mains power supply mode. During this period, pre-synchronization control of switching the power supply mode of each emergency power supply vehicle to the mains power supply mode is realized.

[0087] Embodiment 2 of the present invention provides a seamless power transfer control system for connecting multiple emergency power supply vehicles to a power distribution network, including:

[0088] Through the voltage control module based on the virtual impedance method, the virtual impedance is adjusted to control multiple emergency power supply vehicles to output power in proportion to their own capacity when they are connected to the distribution network in parallel;

[0089] Through the synchronization module based on bus voltage tracking, each emergency power supply vehicle that has adjusted its virtual impedance to control its output power in proportion is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when it is in the emergency power supply vehicle access mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode, so that the voltage of each emergency power supply vehicle always tracks the bus voltage, which is used to seamlessly convert the mains power to each emergency power supply vehicle or multiple emergency power supply vehicles to the mains power supply.

[0090] Embodiment 3 of the present invention provides a seamless power transfer control device for connecting multiple emergency power supply vehicles to a distribution network, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method described in Embodiment 1.

[0091] Embodiment 4 of the present invention provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method described in Embodiment 1 of the present invention are implemented.

[0092] The beneficial effects of the present invention are as follows:

[0093] (1) The present invention realizes power decoupling by using a voltage control method based on a virtual impedance method and utilizing equivalent impedance to simulate the effect of actual physical impedance. The power ratio of each emergency power supply vehicle can be dynamically adjusted in a scenario where multiple emergency power supply vehicles are connected in parallel.

[0094] (2) Through the synchronous control method based on bus voltage tracking, the synchronous control of each emergency power supply vehicle in the mains power supply mode and the emergency power supply vehicle power supply mode, as well as the pre-synchronous control of the emergency power supply vehicle access mode and the emergency power supply vehicle power supply mode switching to the mains power supply mode can be achieved.

[0095] (3) In both the mains power supply mode and the emergency power supply vehicle power supply mode, all emergency power supply vehicles always collect virtual bus voltage phase information for synchronous control, and the synchronous control and pre-synchronous control use the same control algorithm, without the need to switch control strategies; it can safely, reliably, flexibly and efficiently control the joint power supply and withdrawal of multiple emergency power supply vehicles, realizing zero-perception, non-stop maintenance or temporary power supply and other emergency power supply operations for users.

[0096] (4) Each emergency power supply vehicle has an equal status, and the shutdown of any emergency power supply vehicle will not affect the normal operation of the system.

[0097] The present disclosure may be a system, a method and / or a 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.

[0098] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0099] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0100] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0101] 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 relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A seamless power transfer control method for multiple emergency power supply vehicles connected to a distribution network, characterized in that: include: Through the voltage control method based on the virtual impedance method, the virtual impedance is adjusted to control multiple emergency power supply vehicles to output power in proportion to their own capacity when they are connected to the distribution network in parallel; Through the synchronous control method based on bus voltage tracking, each emergency power supply vehicle that has adjusted its virtual impedance to control its output power in proportion is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when the emergency power supply vehicle is in access mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode, so that the voltage of each emergency power supply vehicle always tracks the bus voltage, which is used to seamlessly convert the mains power to each emergency power supply vehicle or multiple emergency power supply vehicles to the mains power supply.

2. According to claim 1, a seamless power transfer control method for multiple emergency power supply vehicles connected to a power distribution network is characterized in that: Through the voltage control method based on the virtual impedance method, by adjusting the virtual impedance, multiple emergency power supply vehicles are controlled to output power in proportion to their own capacity when connected to the distribution network in parallel. Specifically: In both the mains power supply mode and the emergency power supply vehicle power supply mode, the emergency power supply vehicle is set to the voltage source control mode, and the no-load output voltage of each emergency power supply vehicle is set to Controlled to be equal, the virtual impedance R of each emergency power supply vehicle i Make settings so that each emergency power supply vehicle can output power in proportion to its own capacity.

3. A seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network according to claim 2, characterized in that: The active power P output when the i-th emergency power supply vehicle is connected to the distribution network i and reactive power Q i The calculation formula is: Where, U0 is the effective value of bus voltage; U i is the effective value of the no-load output voltage of the i-th emergency power supply vehicle; R i is the virtual impedance between the i-th emergency power supply vehicle and the bus; Output voltage phase of the i-th emergency power supply vehicle; No-load output voltage U of each emergency power supply vehicle i Equal to the collected AC bus voltage U0, when the output voltage phase of each emergency power supply vehicle is When the active power P of each emergency power supply vehicle is equal, i and reactive power Q i Both with virtual impedance R i The virtual impedance is inversely proportional to the capacity and power ratio of each emergency power supply vehicle.

4. A seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network according to claim 1, characterized in that: The synchronous control method based on bus voltage tracking performs synchronous control on each emergency power supply vehicle whose output power is proportionally controlled after adjusting the virtual impedance, in the mains power supply mode and the emergency power supply vehicle power supply mode, specifically: Construct a virtual bus voltage; In the mains power supply mode, the bus voltage and virtual bus voltage are provided by the main grid, and each emergency power supply vehicle tracks the virtual bus voltage to output the specified reactive power to achieve synchronous control; In the emergency power supply vehicle power supply mode, the bus voltage and the virtual bus voltage are jointly generated by each emergency power supply vehicle. The emergency power supply vehicle tracks the virtual bus voltage to achieve synchronous control. Among them, the voltage phase difference between the emergency power supply vehicle and the bus and the reactive power output of the emergency power supply vehicle are determined by the load.

5. According to claim 1, a seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network is characterized in that: Through the synchronous control method based on bus voltage tracking, each emergency power supply vehicle whose output power is proportionally controlled after adjusting the virtual impedance is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when the emergency power supply vehicle is connected to the mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode; specifically: Step 1: Assume that the initial phase angle of the output voltage of each emergency power supply vehicle is Step 2, wait for the interruption. After the interruption is satisfied, check whether the emergency power supply vehicle i has received the pre-synchronization instruction. If the pre-synchronization instruction is not received, it is determined that it is in the mains power supply mode or the emergency power supply vehicle power supply mode at this time, and step 3 is executed; otherwise, it is determined that it is in the emergency power supply vehicle access mode or the emergency power supply vehicle power supply mode is switched to the mains power supply mode, and step 4 is executed; Step 3, construct the virtual bus voltage, execute the set synchronization algorithm, each emergency power supply vehicle tracks the virtual bus voltage phase, realizes synchronization control, and returns to step 2; Step 4: Set the grid voltage to the synchronous voltage, start pre-synchronization control, and calculate the iterative angle difference between the tth interruption and the t+1th interruption and Determine whether it is satisfied ε sets the threshold value. If yes, the pre-synchronization is completed and step 5 is executed. Otherwise, it returns to step 2. Step 5: Determine whether the emergency power supply vehicle is connected. If so, close the corresponding emergency power supply vehicle interface switch, switch the synchronous voltage to the bus voltage, end the pre-synchronization instruction at the same time, and return to step 2; otherwise, close the grid-connected switch, and after completion, disconnect all emergency power supply vehicle interface switches to end the control; Among them, the emergency power supply vehicle interface switch is a switch between the emergency power supply vehicle and the distribution network. When closed, the power supply vehicle is connected to the distribution network; the grid-connected switch is a switch between the mains power and the distribution network. When closed, the mains power is connected to the distribution network.

6. A seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network according to claim 5, characterized in that: In step 3, the virtual bus voltage is specifically: the amplitude of the virtual bus voltage is set to be equal to the bus voltage amplitude, and the phase of the virtual bus voltage is set to be the leading bus voltage phase Virtual Phase Difference It is equal to the phase difference between the output voltage of the emergency power supply vehicle and the bus voltage set in the case of grid connection, and the virtual bus voltage It is expressed by the following formula: Where: U0 is the effective value of bus voltage; is the bus voltage phase angle; virtual phase difference The reactive power command value Q * Determine, the formula is: Among them, R i is the virtual impedance between the i-th emergency power supply vehicle and the busbar, U i is the effective value of the no-load output voltage of the i-th emergency power supply vehicle.

7. A seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network according to claim 6, characterized in that: In step 3, each emergency power supply vehicle tracks the virtual bus voltage phase to achieve synchronous control, and its control expression is: in: Where: is the voltage phase of the emergency power supply vehicle i when it is interrupted for the tth time, To control the voltage phase of emergency power supply vehicle i at the t+1th interruption, k is the proportional coefficient, f0 is the fundamental frequency, and T is the interruption period.

8. A seamless power transfer control method for connecting multiple emergency power supply vehicles to a power distribution network according to claim 7, characterized in that: The pre-synchronization control and synchronization control described in step 4 use the same control expression.

9. A seamless power transfer control system for multiple emergency power supply vehicles connected to a distribution network, used to implement the method described in any one of claims 1 to 8, characterized in that: The system comprises: Through the voltage control module based on the virtual impedance method, the virtual impedance is adjusted to control multiple emergency power supply vehicles to output power in proportion to their own capacity when they are connected to the distribution network in parallel; Through the synchronous control module based on bus voltage tracking, each emergency power supply vehicle that has adjusted its virtual impedance to control its output power in proportion is synchronously controlled in the mains power supply mode and the emergency power supply vehicle power supply mode, and the emergency power supply vehicle is pre-synchronized when the emergency power supply vehicle is in access mode and when the emergency power supply vehicle power supply mode is switched to the mains power supply mode, so that the voltage of each emergency power supply vehicle always tracks the bus voltage, which is used to seamlessly convert the mains power to each emergency power supply vehicle or multiple emergency power supply vehicles to the mains power supply.

10. A seamless power transfer control device for multiple emergency power supply vehicles connected to a distribution network, comprising a processor and a storage medium, characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-8.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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