CN211790791U - An automated microgrid system - Google Patents

Abstract

An automated micro-grid system relates to a power grid technology, in particular to an automated micro-grid system. It is integrated into the low-voltage power supply bus of the micro-grid through the grid-connected inverter, and then boosted to 10KV through the power supply transformer, and then integrated into the national grid. This kind of micro-grid system can not only realize stable power supply in the network, but also can smoothly connect to the large power grid system. Including photovoltaic power generation system, diesel generator system, battery energy storage system, of which photovoltaic power generation system and diesel generator are used as distributed power supply, battery energy storage system; the whole microgrid system is divided into six modules: namely the reference power module, photovoltaic power generation With the grid-connected control module, diesel generator and its intelligent control system module, energy storage system and its intelligent management module, load intelligent management module, system grid-connected module, as a complete power system, it relies on its own control and management to supply energy. Power balance control, system operation optimization, fault detection and protection, power quality management and other functions.

Description

An automated microgrid system

technical field

The utility model relates to a power grid technology, in particular to an automated micro-grid system.

Background technique

Power balance is the basis for the stable operation of the power system. Once the power is seriously unbalanced due to a fault, the system may lose its stability and lead to large-scale power outages, resulting in significant economic losses and serious social impacts. In order to solve this problem, the traditional method It is to use relay protection and safety and stability control devices to perform operations such as machine cutting, load shedding or system decoupling when the system fails, so as to alleviate the power imbalance problem caused by faults in the system as much as possible. This kind of stable control measures is called Passive stabilization, if there is such a device, it can feel the unbalanced power of the system online and real-time, and directly compensate and adjust it, so as to solve the problem of power system stability caused by power imbalance after failure. This kind of stability control It is called active stabilization.

The main method to achieve active self-stabilization is to control various energy storage technologies with the stability of the power system. At present, most of the research is on superconducting magnetic energy storage technology, SMES, fuel capacitor energy storage technology, supercapacitor energy storage technology and Energy storage flywheel energy storage technology, from the current research progress, superconducting magnetic energy storage technology, SMES, super capacitor energy storage technology, energy storage flywheel energy storage technology may reach maturity and industrialization in the power system. Studies have shown that the superconducting magnetic energy storage technology SMES is very suitable for power system stability control, but SMES is expensive, device design, operation and maintenance are very different from the existing various radiation equipment in the power system. Safe and stable operation is under exploration, and the supercapacitor energy storage technology has not yet reached the experimental stage due to the high cost of counterfeiting and the low energy storage density of a single capacitor.

SUMMARY OF THE INVENTION

The purpose of the utility model is to provide an automated micro-grid system, which adopts a photovoltaic power generation system and a diesel power generation system as a distributed power source, adopts a vanadium flow battery as an energy storage system, and uses a synchronous generator for energy storage flywheel energy storage to generate a parallel connection of the system. The grid reference power supply is merged into the micro-grid AC bus through the grid-connected inverter, and then boosted to 10KV by the power supply transformer, and merged into the national grid. This kind of micro-grid system can not only realize stable power supply in the network, but also can smoothly connect to the large power grid system.

The technical scheme of the utility model is: an automated micro-grid system, comprising a photovoltaic power generation system, a diesel power generation system, and a battery energy storage system, wherein the photovoltaic power generation system and the diesel power generation system are used as distributed power sources; the entire micro-grid system is divided into six modules : namely the reference power module, photovoltaic power generation and grid-connected control module, diesel power generation and its intelligent control system module, energy storage system and its intelligent management module, load intelligent management module, system grid-connected module, characterized in that: the reference power supply The module includes photovoltaic array A, CCS intelligent control center, motor, energy storage flywheel, and synchronous generator. The photovoltaic array A is connected to the CCS intelligent control center, the CCS intelligent control center is connected to the motor, the motor output shaft is connected to the energy storage flywheel, and the flywheel shaft is connected. The other end is connected to the synchronous generator. The synchronous generator is merged into the AC bus through the grid-connected inverter for power supply in the micro-grid. At the same time, the AC bus is boosted to the grid voltage by the power supply transformer and merged into the national grid. The principle is that the photovoltaic array The electric energy generated by A starts the source power through CCS, and the source power drives the motor to drive the energy storage flywheel to store energy and drive the synchronous generator to emit 380V/50Hz alternating current; when the load power fluctuates greatly, the energy storage flywheel is used to store energy to stabilize the system voltage and frequency , in order to achieve the power balance of the micro-grid system; while providing the grid-connected reference power supply, it also provides a certain amount of electrical energy to the system; when the solar power is insufficient in rainy weather, the intelligent energy storage system is used to discharge to maintain the grid-connected reference power supply stability. , and automatically turn on the diesel generator as needed to supplement the energy of the micro-grid system, so as to ensure the stable and reliable supply of power to the system.

A further described automated micro-grid system is characterized in that: the CCS intelligent control center includes photovoltaic one-way input control, low-voltage power supply bus connection, active load connection and control, variable voltage energy storage, variable voltage discharge, 12-volt power supply , the photovoltaic one-way input control includes a switch and a diode, the switch is connected to the solar panel, the other end of the switch is connected to a diode, and the diode is connected to the bus; the active load is connected and the control is connected to the low-voltage power supply bus; The discharge is connected to the low-voltage power supply bus, in which the step-down control of the transformer energy storage is connected to the energy storage; the transformer discharge boost control is also connected to the energy storage, and the operation process is that the current emitted by the photovoltaic flows into the diode through the switch, It flows into the low-voltage power supply bus, and the low-voltage power supply bus supplies power to the electrical load. When the photovoltaic microgrid has excess power, the charging control connected to the low-voltage power supply bus will also charge the energy storage battery, and at the same time, the active load can be activated to consume the excess power; when the photovoltaic microgrid When the power is insufficient, the discharge control is connected to the low-voltage power supply bus to boost the energy storage battery into the microgrid, and at the same time, the active load will be cut off.

Further, the automatic micro-grid system is characterized in that: the CCS intelligent control center further includes a super capacitor, and the super capacitor is arranged and connected between the low-voltage power supply buses.

Further, an automated micro-grid system is characterized in that: the photovoltaic power generation and grid-connected control module includes photovoltaic array B, photovoltaic DC combiner box, photovoltaic grid-connected inverter; the output end of photovoltaic array B is connected to To the photovoltaic DC combiner box, after the combined, the photovoltaic DC power is connected to the photovoltaic grid-connected inverter through the output of the photovoltaic DC combiner box, and the photovoltaic grid-connected inverter is converted into three-phase AC power, and the photovoltaic grid-connected inverter is connected to the AC bus, that is The current is drawn into the AC bus with the grid referenced power supply.

A further described automated micro-grid system is characterized in that: the diesel power generation and its intelligent control system modules include a diesel generator and an intelligent control system; the diesel generator is connected to the intelligent control system, and the intelligent control system is connected to the belt. The AC bus of the grid-connected reference power supply; its main function is to supplement the micro-grid system with energy when the solar power is insufficient in rainy weather to ensure a stable and reliable supply of power to the system.

Further, an automated microgrid system is characterized in that: the energy storage system and its intelligent management module include an energy storage battery pack and an intelligent energy storage control; the output of the energy storage battery pack is connected to the intelligent energy storage control, and the storage battery The battery pack can be connected and merged into the AC bus with grid-connected reference power supply; the main functions are: used to cope with the short-term shortage of photovoltaic power, to provide energy supplement for the micro-grid system; and to work at night for low-power loads such as LED lamps and lanterns , computers, air conditioners, etc. to provide the required power.

Further, an automated microgrid system is characterized in that: the intelligent load management module includes an intelligent load controller; the intelligent load controller is connected to an AC bus with a grid-connected reference power supply; the main function is to The large electricity load in the grid system is managed intelligently to ensure that the microgrid system can run smoothly when the large load is started; the intelligent load controller is also connected to an active load. , the load intelligent controller automatically starts the active load, which includes heat storage, pressure storage, pumped water storage, ice making and refrigeration, etc.; starting the active load can consume as much photovoltaic power as possible, so that no light is abandoned and less light is abandoned.

A further described automated micro-grid system is characterized in that: the grid-connected module of the system includes an AC bus, a low-voltage control system, a power transformer, and a high-voltage power access facility; the AC bus is electrically connected to the low-voltage control system, and the AC bus is also connected to Power transformers, power transformers are connected to high-voltage power access facilities, so that the system grid-connected module connects the microgrid to the high-voltage power transmission line that has been built in the location, or to the line where the microgrid construction has formed a high-voltage power supply network of a certain scale; that is, it is connected to After the photovoltaic power of each distribution site is boosted by the transformer, the power transmission is carried out by the power line of 10KV and above, and the power is transmitted to each power consumption unit at the same time, forming the line of the local high-voltage power supply network.

A further described automated micro-grid system is characterized in that: the micro-grid system is provided with multiple groups of photovoltaic power generation systems connected in parallel on the AC bus and multiple groups of diesel power generation systems on the parallel bus, and multiple groups of battery energy storage systems are formed on the parallel AC bus. .

An intelligent energy management method for an automated microgrid system, which is characterized by:

1) The reference power supply is controlled by the reference power management module to generate the reference standard AC power supply, which is input to the bus; 2) The distributed power supply includes the photovoltaic power generation system and the diesel generator set to find the output current standard on the AC bus through the inverter, and then pass the inverter Electric energy of different frequencies is smoothly converted into AC electric energy of the same frequency as the reference power supply, and the inverter is controlled by the controller to control the output of the distributed power supply, so that the distributed power supply can control the output according to the specified voltage and frequency or active and reactive power; 3) The busbar transmits the current to the electric load and the energy storage system. When the power is surplus, the controller starts the active load power consumption; if it has been connected to the power grid, the busbar will transmit it to the large power grid through the step-up transformer. 4) The microgrid energy management system predicts the output of photovoltaic power generation, and formulates the dispatching plan of dispatchable units according to the predicted output, fuel consumption of fuel units, thermal power demand, etc.; when it is sunny, it relies on photovoltaic power generation to supply the load in the microgrid system during the day, and there is excess electricity. Stored in the energy storage system, if the power is still excess, the controller starts the active load and the diesel generator set stops; if the sunlight is slightly insufficient, the controller starts the diesel generator set, or turns on the energy storage system to discharge to supplement the electricity used by the microgrid; photovoltaic power generation at night Stop, the workload in the microgrid system stops operating, and the diesel generator set and the energy storage system discharge electricity to supply electricity for daily life in the microgrid system.

Further, the method for intelligent energy management of an automated microgrid system is characterized in that: the area covered by the microgrid is relatively large, such as covering the entire industrial park, and the load distribution of each power consumer in the area is not uniform. The same, that is, in the same household electrical unit, the electrical equipment also has different rated power and different start and stop times; especially in the initial stage of microgrid construction or the independent microgrid of electricity consumption units and factories, the power supply scale is small. In order to realize automatic switching such as single operation or parallel operation of diesel generator sets, the intelligent management system needs to automatically select the appropriate unit to generate power according to the load in the microgrid; when the load in the microgrid changes, it will automatically start and The matching unit should not only make the unit work in a reasonable efficiency area, but also realize the uninterrupted power supply, ensure the normal production of the factory, and achieve "seamless connection"; the "reservation registration" intelligent load management mode is adopted:

The load management mode of "reservation registration" mainly includes the following aspects.

1) Register all production equipment with a power of 10KW and above in the microgrid, enter its basic information into the electrical equipment management database of the microgrid intelligent management center, and number it.

2) Set up on-site network in each production area, and conduct on-site management of production equipment.

3) Each production equipment is equipped with an automatic switching distribution box. Install red and green indicator lights and "reservation registration" button on the distribution box.

4) Before the production equipment is put into operation, the red indicator light of the power distribution box is on. After pressing the "Reservation Registration" button, the Microgrid Intelligent Management Center receives the application for "Reservation Registration" and identifies its basic information. The power generation capacity of the system and the capacity of the running diesel generators should be prepared accordingly. If the rated power of the reserved production equipment meets the power supply conditions, the micro-grid intelligent management center will immediately send a notification of permission to put in, and the power supply switch of the distribution box will be automatically put into operation through the on-site network, and the green indicator light will be on. At this time, the user can start the equipment for production. .

5) If the rated power of the production equipment registered in the reservation will exceed the power generation capacity of the photovoltaic power generation system and the load capacity of the running diesel generator, the microgrid intelligent management center will start another diesel generator with a suitable capacity, and the start is completed. . After the operation is stable, a notification for allowing input will be issued, and the power supply switch of the distribution box will be automatically input through the on-site network. At the same time, the green light will be on, and the user can start the equipment for production.

6) After the production equipment registered by appointment starts production, the "registration appointment" procedure is completed, and the micro-grid system will supply power to it stably.

7) In the following cases, a new "appointment registration" is required:

(1) The "reservation registration" is successful, that is, the green indicator light of the power distribution box is on, and the equipment has not been started for more than 10 minutes;

(2) After the production equipment has been shut down, if it needs to be turned on again, it is necessary to make a new "reservation registration".

The above management achieves the purpose of optimizing load usage and energy saving through demand-side management or demand-side response; when the microgrid construction reaches a certain scale, its power supply capacity will become stronger and stronger, and the impact of the start of high-power loads on the microgrid will be less and less obvious.

The electricity load in the microgrid includes heat storage load: such as electric water heater, heat transfer oil heater, pressure storage load: air pump and air storage tank, water storage load: such as water pump, ice making and refrigeration equipment, etc. We put these loads Set to Active Load. When the photovoltaic power generation conditions are good, the load in the grid is insufficient, and the surplus power is large, the microgrid intelligent management center will automatically start these active loads, and store heat, pressure, pumped water, ice making and cooling in advance, and try to make as much as possible. Consume more photovoltaic power, try not to abandon light, reduce light; reduce battery discharge at night and the power supply of diesel generators, effectively reducing the operating cost of the microgrid.

Further, an intelligent energy management method for an automated microgrid system is characterized in that: the CCS intelligent control center, the working method is as follows: using a solar 12-volt power supply, provided with super capacitor control, and battery energy storage is stable The power supply of the reference power supply is stable through the energy storage flywheel, and the power generation output of the reference power supply is stable.

Distributed power generation is divided into non-dispatchable units and dispatchable units according to controllability; photovoltaic power generation mainly depends on the natural environment, has randomness and volatility, belongs to non-dispatchable units, and has a certain degree of predictability, but it still has a certain degree of predictability. Large prediction error; fuel engine diesel units are dispatchable units; the power in the microgrid system mainly comes from photovoltaic power generation, followed by diesel generator sets; among them, diesel generator sets are used as backup power or power supplementary equipment, with automatic start, automatic Grid connection, automatic adjustment of output load and other functions, realize automatic switching of single or multiple diesel generator sets in parallel, so as to ensure the stability of power supply in the area covered by the micro-grid system; the intelligent management system needs to automatically select the appropriate power supply according to the size of the load in the network When the load in the network changes, the matching unit will be automatically started, not only to make the unit work in a reasonable efficiency area, but also to realize the uninterrupted power supply, to ensure the normal production of the factory, and to achieve "seamless connection" .

In the microgrid, the energy storage system mainly includes batteries, energy storage flywheels, and super capacitors; the batteries play the role of peak shaving and valley filling and energy dispatching when connected to the grid, and serve as the central storage unit in the isolated grid to maintain the frequency and voltage stability of the microgrid. ; The energy storage flywheel is used to smooth the instantaneous power fluctuations in the microgrid; due to the low inertia of the super capacitor, the energy storage system can smooth the power fluctuations of the distributed power and load in the microgrid, maintain the real-time power balance of the system, and at the same time It can provide instantaneous power support when the microgrid is connected to the grid and the state of the isolated grid is switched to maintain the stability of the system. The energy storage system is connected to the microgrid through the inverter, and accepts the instructions of the microgrid energy management system to determine the working mode and discharge power. The management goal of the energy storage system depends on the working mode of the microgrid; in the grid-connected mode, it is mainly to ensure the stable output of the distributed power supply, and when the capacity is sufficient, it can play an auxiliary role in peak shaving and valley filling and energy dispatching; in the isolated grid In the mode, the energy storage system is mainly to maintain the stability of the system and reduce the power fluctuation of the end user.

The power load in the coverage area of the microgrid system is different, and the start-up time should also be determined according to the needs of life and production. In order to ensure the stability and reliability of the intelligent micro-grid system and prevent the impact on the intelligent micro-grid system due to the instantaneous increase of the electricity load, the intelligent management system should classify and manage all loads in the area. Manage the electricity used for living, office and production separately to achieve reasonable scheduling.

The load of the microgrid coverage area is divided into ordinary load and controllable load. Common loads mainly include those electrical equipment with small rated power and relatively scattered, such as lighting, door guards, security, communications, elevators and other office power and relatively small power for domestic use. When the solar power is insufficient, this kind of load is mainly powered by the battery through the inverter, and is equipped with a diesel generator of the corresponding capacity for supplementary power supply. Set the priority on the management of electrical equipment. For domestic electrical equipment and production equipment with relatively large power in the area, they are classified as controllable loads.

The beneficial effect of the present utility model is that: the micro-grid system of the present utility model has a relatively stable local high-voltage power supply network, and then more distributed power sources can be incorporated into it according to the actual electricity demand, thus gradually forming a more and more coverage area. Larger and stronger high-voltage power supply network. Specifically:

1. The micro-grid of the present invention is an autonomous system that can realize self-control, protection and management, and can operate either with an external power grid or in isolation. It is a small power generation and distribution system that brings together distributed power sources, energy storage devices, energy replacement devices, related loads and monitoring and protection devices. As a complete power system, relying on its own control and management of energy supply to achieve power balance control, system operation optimization, fault detection and protection, power quality management and other functions;

2. The utility model microgrid realizes flexible and efficient application and grid connection of distributed power sources such as photovoltaic power generation systems and diesel generator sets through photovoltaic power generation and grid-connected control modules, diesel power generation and its intelligent control system modules;

3. The microgrid of the present invention can fully realize the access of distributed power sources of various scales, and realize high and reliable power supply to the load. Through the system grid-connected module, the utility model can realize the company's self-generation and self-use of electric energy, and can also sell the surplus electricity on the grid; on the other hand, when the mains power supply system is out of power, because the system has its own grid-connected reference power supply, the micro-grid system can also be normal. work to provide stable and reliable electric energy for the production and life of the company;

4. The power sources in the microgrid of the present invention are distributed power sources with small capacity, photovoltaic power generation systems, diesel generator sets, and energy storage devices such as super capacitors, energy storage flywheels, and batteries. They are connected to the user side and have the characteristics of low cost, low voltage and low pollution;

5. The microgrid energy storage buffer of the present utility model includes variable voltage energy storage and variable voltage energy storage discharge, and its function is to avoid the instantaneous fluctuation of photovoltaic power and ensure the reliable operation of the equipment; alarm when the photovoltaic power is insufficient and the energy storage discharge reaches a predetermined value, Allow the operator time to react to stop the load.

Description of drawings

Fig. 1 is the schematic diagram of the overall networking mechanism of the present utility model

Fig. 2 is the circuit schematic diagram of CCS intelligent control center in the utility model

Fig. 3 is the control flow schematic diagram of the present utility model

In the figure: reference power module 1, CCS intelligent control center 11, photovoltaic array control point 111, active load control point 112, grid load control point 113, grid load 114, reactor 1141, inverter 1142, control box 1143, transformer Energy storage control 115, transformer energy storage 1151, transformer energy storage discharge 1152, energy storage 1154, CCS control power supply 116, super capacitor 117, grounding device 118, arrester 119, motor 12, energy storage flywheel 13, synchronous generator 14. Brushless exciter 15, grid-connected cabinet A16, photovoltaic array A17, active load 19, photovoltaic power generation system and grid-connected control module 2, photovoltaic array B21, string inverter A22, diesel power generation and its intelligent control system module 3. Diesel generator 31 , grid-connected cabinet B32 , energy storage system and its intelligent management module 4 , energy storage controller 41 , energy storage battery pack 42 , load intelligent management module 5 , system grid-connected module 6 , and AC bus 7 .

Detailed ways

An automated microgrid system in Figure 1, the whole system can be divided into six modules according to their functions, namely the reference power module 1, photovoltaic power generation and grid-connected control module 2, diesel power generation and its intelligent control system module 3, energy storage system and its intelligent management module 4 , load intelligent management module 5 , and system grid-connected module 6 .

The reference power module includes photovoltaic array A17, CCS intelligent control center 11, motor 12, energy storage flywheel 13, synchronous generator 14, photovoltaic array A17 is connected to CCS intelligent control center 11, CCS intelligent control center 11 is connected to motor 12, and motor 12 The output shaft is connected to the energy storage flywheel 13, the other end of the shaft of the energy storage flywheel 13 is connected to the synchronous generator 14, and the synchronous generator 14 is merged into the AC bus 7 through the grid-connected inverter;

The photovoltaic power generation and grid-connected control module includes a photovoltaic array B21, a photovoltaic DC combiner box, and a photovoltaic grid-connected inverter 22; the output end of the photovoltaic array B21 is connected to the DC power through the photovoltaic DC combiner box. After the convergence, the DC power passes through the photovoltaic DC combiner box. The output is connected to the photovoltaic grid-connected inverter 22, which is converted into three-phase alternating current by the photovoltaic grid-connected inverter 22. The photovoltaic grid-connected inverter 22 is connected to the AC bus 7, that is, the current is merged into the AC bus 7 with the grid-connected reference power supply ;

Diesel power generation and its intelligent control system module include diesel generator 31 and intelligent control system 32; diesel generator 31 is connected to intelligent control system 32, and intelligent control system 32 is connected and merged into AC bus 7 with grid-connected reference power supply; its main functions are , when the solar power is insufficient in rainy weather, the micro-grid system will be supplemented with energy to ensure the stable and reliable supply of power to the system;

The energy storage system and its intelligent management module include an energy storage battery pack 42 and its intelligent energy storage control 41; the output of the energy storage battery pack 42 is connected to the intelligent energy storage control 41, and is connected and merged into an AC bus with a grid-connected reference power supply. 7. The main functions are: to cope with the short-term shortage of photovoltaic power, to provide energy supplement for the micro-grid system; and to provide the required electrical energy for low-power loads such as LED lamps, computers, and air conditioners that work at night.

The intelligent load management module includes an intelligent load controller 5 and an electrical load; the intelligent load controller 5 controls the electrical load to be connected and merged into an AC bus 7 with a grid-connected reference power supply; The intelligent management of the electricity load of the photovoltaic system is carried out to ensure that the micro-grid system can run smoothly when the large load is started; in addition, when the photovoltaic power generation conditions are good, the load in the grid is insufficient, and the surplus power is large, the active load is automatically started, and the active load is activated in advance. Heat storage, pressure storage, pumped water storage, ice-making and refrigeration, etc., consume as much photovoltaic power as possible, and try not to abandon light and less light.

The system grid-connected module 6 includes an AC bus 7, a low-voltage control system, a power transformer, and a high-voltage power access facility; the AC bus 7 is electrically connected to the low-voltage control system, and the AC bus is also connected to a power transformer, which is connected to a high-voltage power access facility; the system The grid-connected module 6 connects the microgrid to the high-voltage power transmission line that has been built in the locality, or to the line that has formed a high-voltage power supply network of a certain scale under the construction of the microgrid; and above power lines for power transmission, and at the same time transmit power to each power unit, forming a line of local high-voltage power supply network.

An intelligent energy management method for an automated microgrid system, which is characterized by:

1) The reference power supply is controlled by the reference power management module 1 to generate a reference standard AC power supply, which is input to the AC bus bar 7; 2) The distributed power supply includes the photovoltaic power generation system 2 to find the output current standard on the AC bus bar 7 through the string inverter A22, and then through the string inverter A22. The string inverter A22 and the diesel generator set smoothly convert the electric energy of different frequencies into the AC electric energy of the same frequency as the reference power supply 1 through the grid-connected cabinet B32, and the controller controls the inverter to control the output of the distributed power supply, so that the distribution 3) The AC bus 7 transmits the current to the electric load 5 and the energy storage system 4, and the controller starts the active load 19 to consume electricity when there is more power; When connected to the power grid, the AC bus 7 is transported to the large power grid through the step-up transformer; 4) The micro-grid energy management system predicts the output of photovoltaic power generation, and formulates the dispatchable unit according to the predicted output, fuel consumption of fuel units, thermal power demand, etc. Scheduling plan; when the day is fine, rely on photovoltaic power generation to supply the load in the microgrid system, and the excess power is stored in the energy storage system, and the power is still excess, the controller starts the active load, and the diesel generator set stops; if the sunlight is slightly insufficient, the controller starts diesel power generation Units, or turn on the energy storage system to discharge, to supplement the electricity used by the microgrid; at night, when the photovoltaic power generation stops, the workload in the microgrid system stops operating, and the diesel generator set and the energy storage system discharge electricity to supply electricity for daily life in the microgrid system.

Further, the method for intelligent energy management of an automated microgrid system is characterized in that: the area covered by the microgrid is relatively large, such as covering the entire industrial park, and the load distribution of each power consumer in the area is not uniform. The same, that is, in the same household electrical unit, the electrical equipment also has different rated power and different start and stop times; or in the initial stage of the microgrid construction or the independent microgrid of the electricity unit or factory, the power supply scale is small. , In order to realize automatic switching such as single operation or parallel operation of diesel generator sets, the intelligent management system needs to automatically select the appropriate generator set to generate electricity according to the size of the load in the microgrid, and adapt to the changes in the load in the microgrid. In the reasonable efficiency area, it is necessary to realize the uninterrupted power supply to ensure the normal production of the factory and achieve "seamless connection"; adopt the "reservation registration" intelligent load management mode:

The load management mode of "reservation registration" mainly includes the following steps:

1) Register all production equipment with power of 10KW and above in the microgrid, enter its basic information into the electrical equipment management database of the microgrid intelligent management center, and number it;

2) Set up on-site network in each production area, and conduct on-site management of production equipment;

3) Each production equipment is equipped with an automatic switching distribution box, and the red and green indicator lights and the "reservation registration" button are installed on the distribution box;

4) Before the production equipment is put into operation, the red indicator light of the power distribution box is on. After pressing the "Reservation Registration" button, the Microgrid Intelligent Management Center receives the application for "Reservation Registration" and identifies its basic information. Make corresponding preparations for the power generation capacity of the system and the capacity of the diesel generators in operation; if the rated power of the production equipment registered in the reservation meets the power supply conditions, the microgrid intelligent management center will immediately issue a notification of permission to input, and enable the automatic input of the on-site network. The power switch of the distribution box, the green indicator light is on, at this time, the user can start the equipment for production;

5) If the rated power of the production equipment registered in the reservation will exceed the power generation capacity of the photovoltaic power generation system and the load capacity of the running diesel generator, the microgrid intelligent management center will start another diesel generator with a suitable capacity, and the start is completed. . After the operation is stable, a notification of allowing input is issued, and the power supply switch of the distribution box is automatically turned on through the on-site network. At the same time, the green light is on, and the user can start the equipment for production;

6) For the production equipment registered by appointment, after the production starts, the "reservation registration" procedure is completed, and the micro-grid system will supply power to it stably;

7) In the following cases, a new "appointment registration" is required:

(1) The "reservation registration" is successful, that is, the green indicator light of the power distribution box is on, and the equipment has not been started for more than 10 minutes;

(2) After the production equipment has been shut down, if it needs to be turned on again, it is necessary to make a new "reservation registration".

The above management achieves the purpose of optimizing load usage and energy saving through demand-side management or demand-side response; when the microgrid construction reaches a certain scale, its power supply capacity will become stronger and stronger, and the impact of the start of high-power loads on the microgrid will be less and less obvious.

The electricity load in the microgrid includes heat storage load: such as electric water heater, heat transfer oil heater, pressure storage load: air pump and air storage tank, water storage load: such as water pump, ice making and refrigeration equipment, etc. We put these loads Set to Active Load. When the photovoltaic power generation conditions are good, the load in the grid is insufficient, and the surplus power is large, the microgrid intelligent management center will automatically start these active loads, and store heat, pressure, pumped water, ice making and cooling in advance, and try to make as much as possible. Consume more photovoltaic power, try not to abandon light, reduce light; reduce battery discharge at night and the power supply of diesel generators, effectively reducing the operating cost of the microgrid.

Further, an intelligent energy management method for an automated microgrid system is characterized in that: the CCS intelligent control center, the working method is as follows: using a solar 12-volt power supply, provided with super capacitor control, and battery energy storage is stable The power supply of the reference power supply is stable through the energy storage flywheel, and the power generation output of the reference power supply is stable.

Distributed power generation is divided into non-dispatchable units and dispatchable units according to controllability; photovoltaic power generation mainly depends on the natural environment, has randomness and volatility, belongs to non-dispatchable units, and has a certain degree of predictability, but it still has a certain degree of predictability. Large prediction error; fuel engine diesel units are dispatchable units; the power in the microgrid system mainly comes from photovoltaic power generation, followed by diesel generator sets; among them, diesel generator sets are used as backup power or power supplementary equipment, with automatic start, automatic Grid connection, automatic adjustment of output load and other functions, realize automatic switching of single or multiple diesel generator sets in parallel, so as to ensure the stability of power supply in the area covered by the micro-grid system; the intelligent management system needs to automatically select the appropriate power supply according to the size of the load in the network When the load in the network changes, the matching unit will be automatically started, not only to make the unit work in a reasonable efficiency area, but also to realize the uninterrupted power supply, to ensure the normal production of the factory, and to achieve "seamless connection" .

In the microgrid, the energy storage system mainly includes batteries, energy storage flywheels, and super capacitors; the batteries play the role of peak shaving and valley filling and energy dispatching when connected to the grid, and serve as the central storage unit in the isolated grid to maintain the frequency and voltage stability of the microgrid. ; The energy storage flywheel is used to smooth the instantaneous power fluctuations in the microgrid; due to the low inertia of the super capacitor, the energy storage system can smooth the power fluctuations of the distributed power and load in the microgrid, maintain the real-time power balance of the system, and at the same time It can provide instantaneous power support when the microgrid is connected to the grid and the state of the isolated grid is switched to maintain the stability of the system. The energy storage system is connected to the microgrid through the inverter, and accepts the instructions of the microgrid energy management system to determine the working mode and discharge power. The management goal of the energy storage system depends on the working mode of the microgrid; in the grid-connected mode, it is mainly to ensure the stable output of the distributed power supply, and when the capacity is sufficient, it can play an auxiliary role in peak shaving and valley filling and energy dispatching; in the isolated grid In the mode, the energy storage system is mainly to maintain the stability of the system and reduce the power fluctuation of the end user.

The power load in the coverage area of the microgrid system is different, and the start-up time should also be determined according to the needs of life and production. In order to ensure the stability and reliability of the intelligent micro-grid system and prevent the impact on the intelligent micro-grid system due to the instantaneous increase of the electricity load, the intelligent management system should classify and manage all loads in the area. Manage the electricity used for living, office and production separately to achieve reasonable scheduling.

The load of the microgrid coverage area is divided into ordinary load and controllable load. Common loads mainly include those electrical equipment with small rated power and relatively scattered, such as lighting, door guards, security, communications, elevators and other office power and relatively small power for domestic use. When the solar power is insufficient, this kind of load is mainly powered by the battery through the inverter, and is equipped with a diesel generator of the corresponding capacity for supplementary power supply. Set the priority on the management of electrical equipment. For domestic electrical equipment and production equipment with relatively large power in the area, they are classified as controllable loads.

Claims (8)

1. An automatic micro-grid system comprises a photovoltaic power generation system, a diesel power generation system and a battery energy storage system, wherein the photovoltaic power generation system and the diesel power generation system are used as distributed power supplies; the micro-grid system is divided into six modules: namely a reference power module, a photovoltaic power generation and grid-connected control module, a diesel power generation and intelligent control system module, an energy storage system and intelligent management module, a load intelligent management module and a system grid-connected module, and is characterized in that: the reference power supply module comprises a photovoltaic array A, CCS intelligent control center, a motor, an energy storage flywheel and a synchronous generator, wherein the photovoltaic array A is connected with the CCS intelligent control center, the CCS intelligent control center is connected with the motor, the motor output shaft is connected with the energy storage flywheel, the other end of an energy storage flywheel shaft is connected with the synchronous generator, the synchronous generator is connected into an alternating current bus through a photovoltaic grid-connected inverter and used for supplying power in the microgrid, and meanwhile, the alternating current bus is boosted to the voltage of a power grid through a power supply transformer and is connected into a national power.

2. The automated microgrid system of claim 1, wherein: the CCS intelligent control center also comprises a super capacitor, and the super capacitor is connected between the low-voltage power supply buses.

3. The automated microgrid system of claim 1, wherein: the photovoltaic power generation and grid-connected control module comprises a photovoltaic array B, a photovoltaic direct current combiner box and a photovoltaic grid-connected inverter; the output end of the photovoltaic array B is connected to a photovoltaic direct current combiner box, after the combination, the photovoltaic direct current is output through the photovoltaic direct current combiner box and connected with a photovoltaic grid-connected inverter, the photovoltaic grid-connected inverter inverts the photovoltaic direct current into three-phase alternating current, the photovoltaic grid-connected inverter is connected with an alternating current bus, and the current is merged into the alternating current bus with a grid-connected reference power supply.

4. The automated microgrid system of claim 1, wherein: the diesel power generation and intelligent control system module comprises a diesel generator and an intelligent control system; the diesel generator is connected with an intelligent control system, and the intelligent control system is connected with an alternating current bus with a grid-connected reference power supply.

5. The automated microgrid system of claim 1, wherein: the energy storage system and the intelligent management module thereof comprise an energy storage battery pack and intelligent energy storage control; the output of the energy storage battery pack is connected with the intelligent energy storage control, and the energy storage battery pack is connected with an alternating current bus with a grid-connected reference power supply.

6. The automated microgrid system of claim 1, wherein: the intelligent load management module comprises an intelligent load controller; the load intelligent controller is connected with an alternating current bus with a grid-connected reference power supply; the load intelligent controller is also connected with an active load, when the photovoltaic power generation illumination is sufficient and the generated energy exceeds the load in the network, the load intelligent controller automatically starts the active load, and the active load is heat storage or pressure storage or water pumping and storage or ice making and refrigeration.

7. The automated microgrid system of claim 1, wherein: the system grid-connected module comprises an alternating current bus, a low-voltage control system, a power transformer and a high-voltage power access facility; the alternating current bus is electrically connected with the low-voltage control system, the alternating current bus is also connected with a power transformer, and the power transformer is connected with a high-voltage power access facility.

8. The automated microgrid system of claim 1, wherein: the micro-grid system is formed by arranging a plurality of groups of photovoltaic power generation system parallel alternating current buses, a plurality of groups of diesel power generation system parallel alternating current buses and a plurality of groups of battery energy storage system parallel buses.

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