CN-122026475-A - Rural light storage cooperative power distribution equipment with wide voltage adaptation and off-grid self-healing capacity and operation method

CN122026475ACN 122026475 ACN122026475 ACN 122026475ACN-122026475-A

Abstract

The invention discloses rural optical storage cooperative power distribution equipment with wide voltage adaptation and off-grid self-healing capacity and an operation method thereof, and belongs to the technical field of rural power distribution network and distributed energy cooperative control. The device integrates six functional modules of wide-voltage photovoltaic access, modularized energy storage, intelligent switching protection, load classified power supply, edge self-adaptive control and dual-channel communication into an integrated outdoor cabinet. The operation method realizes high-efficiency absorption and active voltage support in a grid-connected state through real-time coordination of a local edge controller, and realizes quick off-grid self-healing and continuous power supply of key loads in the case of grid faults. The invention effectively solves the problems of severe voltage fluctuation, poor power supply reliability and lack of professional operation and maintenance of the rural power grid caused by high-proportion photovoltaic access, has the characteristics of instant assembly and use, no network autonomy and key power supply, and remarkably improves the toughness of the weak rural power grid.

Inventors

JI XIAOTONG
GE LEIJIAO
JIN YUHAN
CAO KAN
ZHU XIAOQIAN
LI ZHE
SU LEI
Xiong Liangli
CAI XUAN
WEI MINGJIANG
FENG WANLI

Assignees

国网湖北省电力有限公司电力科学研究院

Dates

Publication Date: 20260512
Application Date: 20260117

Claims (10)

1. Rural light stores up cooperative distribution equipment that possesses wide voltage adaptation and off-grid self-healing ability, its characterized in that, equipment is whole to be integrated in the standardized outdoor rack that the protection level is not less than IP54, and inside constitutes rated current 250A's main alternating current busbar through high conductivity copper bar to realize the intermodule control signal interaction through industrial level CAN 2.0B bus, the equipment includes: The input end of the photovoltaic access unit is connected with the photovoltaic module array, and the output end of the photovoltaic access unit is connected to the intelligent switching and protecting unit through the main alternating current bus and is used for converting photovoltaic direct current into alternating current and feeding the alternating current into the system; the direct current side of the modularized energy storage unit is connected to the photovoltaic access unit and the energy storage converter through a high-voltage direct current busbar, and the alternating current side of the modularized energy storage unit is connected to the intelligent switching and protecting unit through the main alternating current busbar; The intelligent switching and protecting unit is connected in series between the incoming line of the power grid and the main alternating current bus, is used for switching between grid-connected and off-grid modes and providing residual current and surge protection, and a control end of the intelligent switching and protecting unit receives an instruction of the edge self-adaptive control unit to execute switching action; The key load grading power supply unit comprises a plurality of intelligent miniature circuit breakers, a main alternating current bus and a main alternating current bus, wherein the input end of the key load grading power supply unit is connected with the main alternating current bus, and the output end of the key load grading power supply unit is respectively connected with a primary load loop, a secondary load loop and a tertiary load loop; The edge self-adaptive control unit is used as a core controller, a signal acquisition end of the edge self-adaptive control unit is connected to a voltage/current sensor of the main alternating current bus, and an instruction output end of the edge self-adaptive control unit is connected with a photovoltaic access unit, a modularized energy storage unit, an intelligent switching and protecting unit, a key load grading power supply unit and a virtual load unit through the CAN 2.0B bus; And the input end of the virtual load unit is connected with the main alternating current bus, and the control end of the virtual load unit receives the instruction of the edge self-adaptive control unit and is used for inputting a resistive load when overvoltage occurs and the energy storage unit cannot continuously absorb power, so that more residual photovoltaic power generation is consumed in situ.
2. The device of claim 1, wherein the photovoltaic access unit is provided with a low voltage ride through circuit and a dynamic reactive power regulation module, supports 160-280V wide voltage input and can provide reactive power support when the power grid voltage is abnormal, maintains grid-connected operation when the power grid voltage drops to 20% of rated value and lasts for 0.15 seconds, meets the standard requirements of GB/T19964-2012, and can stably operate for more than 0.5 seconds under the 30% voltage drop condition.
3. The device of claim 1, wherein the modular energy storage unit adopts a lithium iron phosphate battery module, the single module has a capacity of 5-10 kWh and supports parallel expansion of 2-10 modules, the battery management system monitors the voltage, temperature, state of charge and health of the single module in real time and executes active equalization control, the heat dissipation mode is natural air cooling, a diversion air duct and a temperature control shutter are arranged in the heat dissipation mode, and the working temperature range is-20 ℃ to +55 ℃.
4. The optical storage cooperative power distribution device according to claim 1, wherein the intelligent switching and protection unit integrates a residual current operation protector, a multi-stage lightning surge protector and a dual power supply switch, the operation threshold of the residual current operation protector is not more than 30 mA, and the nominal discharge current of the surge protector is not less than 20 kA.
5. The device of claim 1, wherein the key load grading power supply unit realizes remote switching-on and switching-off and current monitoring of a load loop through the intelligent breaker array, supports temporary lifting of the load level of a user loop through a village level mobile management terminal, has a lifting effective period of 1-24 hours, and automatically restores the original level after expiration.
6. The apparatus of claim 1, wherein the edge adaptive control unit is configured to generate and issue coordination control instructions to dynamically coordinate reactive output of the photovoltaic access unit, charging and discharging of the energy storage unit, mode switching of the intelligent switching and protection unit, switching of the load grading power supply unit, and input of the virtual load unit by collecting grid voltage and frequency information in real time and combining the photovoltaic output and the energy storage state, so as to execute overall process control logic of grid connection absorption, voltage active support, off-grid self-healing operation and grid connection recovery.
7. The device of claim 6, wherein the edge adaptive control unit is configured to perform the following voltage regulation strategy: when the line termination voltage is detected to be continuously above 253V or below 198V for more than 10 seconds, If the voltage is overvoltage, controlling the modularized energy storage unit to absorb active power and send out inductive reactive power, and starting the virtual load unit to consume more residual photovoltaic power on site if necessary; If the voltage is under-voltage, controlling the modularized energy storage unit to release active power and send out capacitive reactive power; the voltage is stabilized in the range of 220V plus or minus 7 percent by dynamically adjusting the active/reactive output.
8. The device of claim 1, wherein the device is integrally packaged in a standardized outdoor cabinet with a protection level not lower than IP54, the cabinet is made of galvanized steel plates or stainless steel, cable inlet holes and grounding terminals are reserved at the bottom, a ventilation and heat dissipation grid is arranged at the top, the device supports integral hoisting or forklift carrying, and the on-site deployment time is not longer than 4 hours, and a concrete foundation is not needed.
9. A method of operating rural optical power storage and distribution facilities with wide voltage adaptation and off-grid self-healing capability, characterized by the application of the facility according to any one of claims 1 to 7, comprising the steps of: The method comprises the following steps of S1, grid-connected optimization operation and consumption, wherein in a grid-connected operation state, the output power of a photovoltaic access unit is preferentially supplied to a local load; the edge self-adaptive control unit acquires the output power of the photovoltaic access unit and the total power of the local load in real time, if the photovoltaic output power is greater than the load demand, the surplus electric energy is charged to the modularized energy storage unit preferentially, and when the energy storage charge state reaches 90%, the surplus photovoltaic power generation amount is fed into the power grid after being measured; S2, voltage out-of-limit active support, namely, an edge self-adaptive control unit continuously monitors the voltage of a grid-connected point, and when the voltage is continuously higher than 253V or lower than 198V for 10 seconds, a voltage support strategy is started, namely, aiming at overvoltage, an energy storage unit is instructed to absorb active power and send inductive reactive power, and whether a virtual load unit needs to be started or not is judged based on the real-time charge state of energy storage; S3, grid fault detection and off-grid self-healing, namely dynamically adjusting an island detection threshold value based on online identified grid impedance parameters and executing compound criterion detection when an edge self-adaptive control unit detects that grid voltage is interrupted, frequency is suddenly changed or serious distortion continuously exceeds 200 ms, sending a disconnection instruction to an intelligent switching and protecting unit after confirming island to control the intelligent switching and protecting unit to disconnect a grid point, then controlling an energy storage unit to switch to a voltage source mode to establish an off-grid voltage reference, and instructing a photovoltaic access unit to switch to an off-grid mode, simultaneously supplying power to only one stage of critical load through a critical load grading power supply unit, and further cutting off part of one stage load and pushing alarm when the energy storage charge state is monitored to be lower than 20 percent and the predicted support time is less than 30 minutes; S4, grid recovery and automatic synchronization grid connection, namely when the edge self-adaptive control unit monitors that the voltage and the frequency of an external grid are continuously recovered to a normal range for 10 seconds, synchronous detection is executed, after the voltage, the frequency and the phase deviation are confirmed to meet the synchronous conditions, a closing instruction is sent to the intelligent switching and protecting unit to recover grid connection, and a key load grading power supply unit is instructed to gradually recover the power supply of each level of load according to the priority order; And S5, uploading the whole-course data and performing remote interaction, namely uploading the running state, the event and the alarm data generated in the steps S1 to S4 to a remote management platform through a 4G or Beidou dual-channel by an edge self-adaptive control unit, and simultaneously receiving and executing a remote instruction from a village mobile management terminal to realize temporary adjustment of the load level.
10. The method of claim 9, wherein the synchronization conditions are satisfied by the voltage, frequency, and phase deviations identified in S4, specifically, the voltage amplitude deviation <5V, the frequency deviation <0.2Hz, and the phase difference <5 °.

Description

Rural light storage cooperative power distribution equipment with wide voltage adaptation and off-grid self-healing capacity and operation method Technical Field The invention relates to the technical field of rural power distribution network and distributed energy cooperative control, in particular to rural optical storage cooperative power distribution equipment with wide voltage adaptation and off-grid self-healing capacity and an operation method thereof, which have wide voltage adaptation, fault self-healing, key load guarantee and professional-free operation and maintenance capacity and are suitable for remote and weak rural power grid environments. Background With the implementation of "whole county advancing" distributed photovoltaic policies, rural photovoltaic installation is rapidly growing. However, rural distribution networks generally have the problems of long line, large impedance, low short-circuit capacity, severe voltage fluctuation and the like. High permeability photovoltaic is easy to cause voltage out-of-limit, harmonic distortion, reverse tide and island risk, and power supply safety is threatened. The existing micro-grid or energy storage equipment is dependent on stable communication, professional operation and maintenance and standard grid environment, and is difficult to operate reliably under the conditions of no signal, no electricity, unstable voltage and dispersed load in rural areas. In addition, the traditional power distribution system adopts a distributed equipment combination, wiring is complex, unified control is lacked, and independent key load differentiation is guaranteed to be manufactured, all loads are synchronously powered off when a power grid fails, and the life and emergency response are affected. Therefore, a complete light storage collaborative power distribution solution with high integration, strong self-adaption, convenient deployment and easy operation and maintenance is needed. Disclosure of Invention The invention aims to provide light storage cooperative power distribution equipment specially customized for typical characteristics of weak, scattered, far and variable rural power grids and an operation method thereof. The device can realize the high-efficiency on-site consumption of local energy, the active support of power grid voltage, the rapid self-healing under fault state and the continuous and reliable power supply of key civil load under the background of high-proportion distributed photovoltaic access without structural transformation or large-scale investment upgrading of the existing rural power distribution network. Meanwhile, the system has offline autonomous capability under the conditions of no external communication and no professional operation and maintenance personnel on duty, so that the dependence of rural areas on technical manpower is obviously reduced, and the technical targets of instant assembly and use, no network autonomous, key supply protection and remote visualization are truly realized. In order to achieve the aim, the invention provides the light storage cooperative power distribution equipment which is adaptive to the rural power grid, The invention effectively solves the core pain points of severe voltage fluctuation, frequent power interruption, weak operation and maintenance strength and the like caused by rural high-proportion photovoltaic access through three innovations of high integration of hardware, localization of control algorithm and light interactive mode, and provides a complete technical solution for constructing a novel rural power system which is safe, reliable, intelligent and general. Rural light storage cooperative distribution equipment with wide voltage adaptation and off-grid self-healing capacity, wherein the equipment is integrally integrated in a standardized outdoor cabinet with protection level not lower than IP54, a main alternating current bus with rated current of 250A is formed inside through a high-conductivity copper bar, and control signal interaction among modules is realized through an industrial CAN 2.0B bus, and the equipment comprises: The input end of the photovoltaic access unit is connected with the photovoltaic module array, and the output end of the photovoltaic access unit is connected to the intelligent switching and protecting unit through the main alternating current bus and is used for converting photovoltaic direct current into alternating current and feeding the alternating current into the system; the direct current side of the modularized energy storage unit is connected to the photovoltaic access unit and the energy storage converter through a high-voltage direct current busbar, and the alternating current side of the modularized energy storage unit is connected to the intelligent switching and protecting unit through the main alternating current busbar; The intelligent switching and protecting unit is connected in series between the incoming line of the power grid