Power distribution network planning method based on micro-grid and flexible resource collaborative optimization

Abstract

The application relates to the field of new energy grid connection technology, and particularly discloses a power distribution network planning method for micro-grid and flexible resource coordination optimization, which comprises setting two groups of energy storage devices to store the electric energy of new energy power generation equipment, the two groups of energy storage devices are arranged in parallel with each other, the two groups of energy storage devices are connected with a micro-grid through power electronic interfaces, and a bidirectional energy storage converter is selected as an interface equipment for grid connection operation of the micro-grid and the power distribution network. According to the technical scheme, the two groups of energy storage devices are designed to be used for alternate energy storage and continuous and smooth power supply, so that the electric energy of the new energy power generation equipment is prevented from being wasted, the two groups of energy storage devices are designed to be disconnected in time during switching, the electric energy of the energy storage devices is continuously supplied to the micro-grid, the quality of micro-grid power supply is improved, stable electric energy transmission is provided after the micro-grid and the power distribution network are connected in grid, meanwhile, a monitoring device is arranged to monitor the electric power data of the micro-grid in real time, the micro-grid is disconnected in time and the power distribution network is started to transmit electric power, so that the user electric power stability is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy grid connection technology, in particular to a power distribution network planning method based on micro-grid and flexible resource collaborative optimization. BACKGROUND

[0002] At present, new energy such as solar energy and wind energy has the advantages of being renewable, environmentally friendly, and pollution-free. By connecting these energy sources to microgrids and power distribution networks, energy can be complemented and optimally configured, thereby improving energy utilization efficiency. As an important part of distributed energy systems, microgrids can achieve flexible scheduling and efficient use of energy through connection with power distribution networks, reduce energy waste, and the connection of new energy power can also enhance the security and stability of the power grid. Microgrids have flexible operation control and energy management capabilities, can quickly respond to load fluctuations and emergency situations, and ensure the reliability and stability of power supply. In addition, microgrids can also serve as a useful supplement to large power grids, providing emergency power during power grid failures or power outages to ensure the power needs of important users.

[0003] However, due to the non-continuous nature of new energy generation, there are peak and valley periods of power generation. If the continuity and stability of new energy power transmission are not addressed, new energy power generation cannot be connected to microgrids and power distribution networks for stable operation and use, and improvements are needed. Therefore, we propose a power distribution network planning method based on micro-grid and flexible resource collaborative optimization. SUMMARY

[0004] The purpose of the present application is to provide a power distribution network planning method based on micro-grid and flexible resource collaborative optimization, which solves the problems raised in the background art.

[0005] To achieve the above purpose, the present application provides the following technical solution: a power distribution network planning method based on micro-grid and flexible resource collaborative optimization, comprising the following steps: S1: setting two groups of energy storage devices to store the power of new energy power generation equipment, and the two groups of energy storage devices are arranged in parallel with each other;

[0006] S2: the two groups of energy storage devices are connected to the micro-grid through separate power electronic interfaces, and a bidirectional energy storage converter is selected as the power electronic interface equipment for the grid-connected operation of the micro-grid and the power distribution network;

[0007] S3: setting an electric energy detection device to monitor the electric energy storage capacity of the energy storage device, and setting a power switching structure one between the two groups of energy storage devices and the new energy power generation equipment, and setting a power switching structure two between the two groups of energy storage devices and the micro-grid;

[0008] S4: the electric energy storage of the energy storage device is uploaded to the control center through the electric energy detection device, the two groups of energy storage devices include energy storage device one and energy storage device two, the initial state is that the energy storage device one is in communication with the new energy power generation equipment for electric energy storage, at this time the energy storage device two is in a disconnected state with the new energy power generation equipment, when the energy storage device one reaches the set value, the power switching structure one acts, so that the energy storage device one is disconnected with the new energy power generation equipment, and the energy storage device two is in communication with the new energy power generation equipment for electric energy storage;

[0009] S5: after the energy storage device one is disconnected with the new energy power generation equipment, the power generation mode is started, the energy storage device one stably delivers electric energy to the microgrid, at this time the energy storage device two is in an energy storage state, and the energy storage device two does not deliver electric energy to the microgrid, when the residual electric energy of the energy storage device one is less than the set value, the power switching structure two first connects the energy storage device two with the microgrid, and then the power switching structure one acts, the energy storage device one is in time communication with the new energy power generation equipment, the energy storage device two is in a disconnected state with the new energy power generation equipment, the energy storage device two starts the power generation mode, when the energy storage device two stably delivers electric energy to the microgrid, the power switching structure two disconnects the energy storage device one from the microgrid, and the energy storage device one is in communication with the new energy power generation equipment for energy storage, and the energy storage device two stably supplies power.

[0010] As a preferred embodiment of the technical scheme of the present application, the two groups of energy storage devices are flywheel storage system devices, the flywheel energy storage has good stability and high mechanical energy-electric energy conversion rate.

[0011] As a preferred embodiment of the technical scheme of the present application, the electric energy detection device includes a speed sensor and a signal amplifier, and the speed sensor is any one of an optical encoder and a Hall sensor.

[0012] As a preferred embodiment of the technical scheme of the present application, the power switching structure one includes an industrial-grade remote control relay A connected in series in a circuit between the energy storage device one and the new energy power generation equipment, and an industrial-grade remote control relay B connected in series in a circuit between the energy storage device two and the new energy power generation equipment, and the power switching structure two includes an industrial-grade remote control relay A1 connected in series in a circuit between the energy storage device one and the microgrid, and an industrial-grade remote control relay B2 connected in series in a circuit between the energy storage device two and the microgrid.

[0013] As a preferred embodiment of the technical scheme of the present application, the new energy power generation equipment includes any one of a wind power generation system device and a photovoltaic power generation system device.

[0014] As a preferred embodiment of the technical scheme of the present application, the flywheel speed standard of the energy storage device reaching the set value is 30000 rpm to 60000 rpm, and the flywheel speed standard of the energy storage device with insufficient residual electric energy is 600 rpm to 1200 rpm.

[0015] As a preferred embodiment of the technical scheme of the present application, in step S2, the micro-grid and the power distribution network are connected in series with a high-voltage circuit breaker, and a monitoring device is arranged to monitor the voltage, frequency and harmonic of the output power of the micro-grid, and when the voltage, frequency and harmonic of the output power of the micro-grid do not meet the standard of the power distribution network, the high-voltage circuit breaker timely disconnects the connection with the micro-grid.

[0016] As a preferred embodiment of the technical scheme of the present application, the high-voltage circuit breaker is a remote control high-voltage relay.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] The technical scheme of the present application is designed to store energy alternately and supply power continuously by two groups of energy storage devices, so as to avoid waste of the power of the new energy power generation equipment, and the power of the energy storage devices is continuously supplied to the micro-grid when the two groups of energy storage devices are switched over by using a time delay disconnection design, so as to improve the quality of the power supply of the micro-grid, provide stable power transmission after the micro-grid is connected to the power distribution network, and at the same time, a monitoring device is arranged to monitor the power data of the micro-grid in real time, so as to timely disconnect the micro-grid and enable the power distribution network to transmit power, thereby ensuring the stability of the power use of users. DETAILED DESCRIPTION

[0019] The technical scheme in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments.

[0020] Embodiment 1: The present application provides a technical scheme of a micro-grid and flexible resource collaborative optimization power distribution network planning method, which comprises the following steps:

[0021] S2: The two groups of energy storage devices are connected to the micro-grid through separate power electronic interfaces, and a bidirectional energy storage converter is selected as the power electronic interface equipment for the grid-connected operation of the micro-grid and the power distribution network; in step S2, the micro-grid and the power distribution network are connected in series with a high-voltage circuit breaker, and a monitoring device is arranged to monitor the voltage, frequency and harmonic of the output power of the micro-grid, and when the voltage, frequency and harmonic of the output power of the micro-grid do not meet the standard of the power distribution network, the high-voltage circuit breaker timely disconnects the connection with the micro-grid

[0022] S3: An electric energy detection device is arranged to monitor the electric energy storage capacity of the energy storage devices, and an electric power switching structure one is arranged between the two groups of energy storage devices and the new energy power generation equipment, and an electric power switching structure two is arranged between the two groups of energy storage devices and the micro-grid.

[0023] S4: The electric energy storage of the energy storage device is uploaded to the control center through the electric energy detection device, the two groups of energy storage devices include energy storage device one and energy storage device two, the initial state is that the energy storage device one is in communication with the new energy power generation equipment for electric energy storage, at this time the energy storage device two is in a disconnected state with the new energy power generation equipment, when the energy storage device one reaches the set value, the power switching structure one acts, so that the energy storage device one is disconnected with the new energy power generation equipment, and the energy storage device two is in communication with the new energy power generation equipment for electric energy storage;

[0024] S5: After the energy storage device one is disconnected with the new energy power generation equipment, the power generation mode is started, the energy storage device one stably delivers electric energy to the micro-grid, at this time the energy storage device two is in an energy storage state, and the energy storage device two does not deliver electric energy to the micro-grid, when the residual electric energy of the energy storage device one is lower than the set value, the power switching structure two first connects the energy storage device two with the micro-grid, then the power switching structure one acts, the energy storage device one is in time communication with the new energy power generation equipment, the energy storage device two is in a disconnected state with the new energy power generation equipment, the energy storage device two starts the power generation mode, when the energy storage device two stably delivers electric energy to the micro-grid, the power switching structure two disconnects the energy storage device one with the micro-grid, and the energy storage device one is in communication with the new energy power generation equipment for energy storage, and the energy storage device two stably supplies power.

[0025] In one specific embodiment of the present application, the new energy power generation equipment is a wind power generation system component, and the key components include a wind wheel, a generator and a power transmission cable, the mechanical energy generated by the wind wheel drives the generator, the magnetic field induction principle in the generator generates electric energy, and the electric energy is transmitted to the energy storage device through the cable;

[0026] The energy storage device is a flywheel energy storage device, which is composed of a flywheel, a bearing system, a vacuum chamber, a motor and a monitoring system, the flywheel is the core component of the energy storage device and is responsible for storing energy, the bearing system is used to support the flywheel and reduce the friction loss during rotation, and the bearing type includes mechanical bearings and magnetic bearings. The magnetic bearing suspends the flywheel by magnetic force, further reduces the friction loss and improves the energy storage efficiency, the vacuum chamber provides a low vacuum environment to reduce the influence of air resistance on the rotation of the flywheel, thereby reducing the friction loss and improving the energy storage efficiency, the motor plays a dual role in the flywheel energy storage device. In the charging stage, it drives the flywheel to rotate as a motor, and in the discharging stage, it converts the mechanical energy of the flywheel into electric energy as a generator, a direct current permanent magnet brushless synchronous motor is adopted to realize high-efficiency and stable energy conversion, and the monitoring system is used to monitor various parameters of the flywheel energy storage device in real time, such as the flywheel speed, the motor temperature and the vacuum degree, and provides fault early warning and alarm functions;

[0027] The wind power generation of new energy power generation equipment generates direct current, while the driving motor needs alternating current, so an inverter is needed to convert direct current to alternating current, which drives the flywheel of the energy storage device to rotate and converts electrical energy into mechanical energy of the flywheel rotation;

[0028] When the flywheel of the energy storage device reaches the set speed, it is easy to cause safety accidents if it continues to speed up, so the stored mechanical energy needs to be released as electrical energy and delivered to the microgrid. In the flywheel energy storage device, the flywheel stores a large amount of kinetic energy when rotating at high speed. When it is necessary to release electrical energy, the flywheel starts to rotate at a slower speed, and its kinetic energy is converted into electrical energy. The flywheel energy storage device converts the generated electrical energy into alternating current or direct current that meets the requirements of the microgrid through power electronic equipment (such as an inverter). The flywheel energy storage device is connected to the microgrid through a connection line (such as a cable). In the microgrid, the energy management system (EMS) is responsible for monitoring and controlling the operating state of each distributed power source and energy storage system. When the flywheel energy storage device releases electrical energy, the EMS will monitor and adjust it to ensure that it works cooperatively with other components in the microgrid. In grid-connected operation mode, the electrical energy released by the flywheel energy storage device is transmitted directly to the microgrid through the connection line and exchanged with the main grid. At this time, the EMS will ensure that the output power of the flywheel energy storage device matches the demand of the microgrid. In off-grid operation mode (also known as island operation), the microgrid is disconnected from the distribution network, and the distributed power source and energy storage device work together to supply power to the load. At this time, the electrical energy released by the flywheel energy storage device becomes one of the important power sources in the microgrid. The EMS will monitor the load demand and adjust the output power of the flywheel energy storage device to ensure the stable operation of the microgrid.

[0029] The specific steps of alternating charging of the two groups of energy storage devices and stable supply of the microgrid are as follows:

[0030] In the initial state, the industrial-grade remote control relay A is in the closed state, the industrial-grade remote control relay B is in the open state, the industrial-grade remote control relay A1 is in the closed state, the industrial-grade remote control relay B2 is in the open state, the motor of the energy storage device one is in the charging function, the energy storage device one stores the electric energy of the new energy power generation equipment and converts it into mechanical energy, the speed of the flywheel of the energy storage device one is continuously improved, and the speed of the flywheel of the energy storage device one is set to 50000r / min as the limit speed, when the speed of the flywheel is monitored to reach 50000r / min by the speed sensor of the energy storage device one, the controller of the control center connected with the power switching structure one remotely controls the industrial-grade remote control relay A to be in the open state and the industrial-grade remote control relay B to be in the closed state, at this time, the motor of the energy storage device two is in the charging function and continues to store the electric energy into the flywheel of the energy storage device two, the electric energy of the energy storage device one is converted into alternating current or direct current meeting the requirements of the micro-grid through the power electronic equipment, the micro-grid first delivers the electric energy to the nearby area, if the power consumption of the nearby area is much lower than the power generation, the excess electric energy is delivered to the power distribution network, the speed of the flywheel of the energy storage device one is monitored in real time by the speed sensor, when the speed of the flywheel of the energy storage device one is lower than 1000r / min, there is a risk of power failure of the micro-grid if the power supply continues, at this time, the power switching structure two is needed to connect the energy storage device two with the micro-grid (that is, the industrial-grade remote control relay B2 is controlled to be in the closed state), then the power switching structure one acts, the energy storage device one is connected with the new energy power generation equipment in a time delay (it is set that the energy storage device two is connected after stable power supply), the energy storage device two is in the open state with the new energy power generation equipment, the energy storage device two starts the power generation mode, when the energy storage device two stably delivers the electric energy to the micro-grid, the power switching structure two disconnects the energy storage device one with the micro-grid, the energy storage device one is connected with the new energy power generation equipment for energy storage, and the energy storage device two stably supplies power; when the flywheel of the energy storage device two is lower than the above speed, the switching is performed according to the above steps to ensure the continuity of the electric energy delivered by the energy storage device; if the power generation of the new energy power generation equipment is lower than the power consumption of the micro-grid area, the remote control high-voltage relay between the micro-grid and the power distribution network is disconnected to avoid the instability of the micro-grid affecting the power distribution network, wherein the remote control high-voltage relay is a reliable remote control device suitable for electric energy control in various harsh environments, which has multiple input and output control terminals, can be easily connected to the light energy circuit, and can be controlled by remote signals to open and close, the industrial-grade remote control relay supports multiple communication protocols and interface modes, and can be easily connected to various control systems and communication networks.

[0031] In summary, the embodiment of the present application introduces in detail the design of two groups of energy storage devices for alternating energy storage and continuous and smooth power supply, avoiding the waste of the electric energy of the new energy power generation equipment, using the time delay opening design when the two groups of energy storage devices are switched, so that the electric energy of the energy storage device is continuously supplied to the micro-grid, improving the quality of the micro-grid power supply, so that the micro-grid and the distribution network are connected in grid to provide stable electric energy transmission, and at the same time, the monitoring device is arranged to monitor the electric power data of the micro-grid in real time, and the distribution network is disconnected and started in time to transmit electric power, ensuring the stability of the user power consumption.

Claims

1. A power distribution network planning method for microgrid and flexibility resource coordination optimization, characterized in that: The method comprises the following steps: S1: setting two groups of energy storage devices to store the electric energy of the new energy power generation equipment, and the two groups of energy storage devices are connected in parallel with each other; S2: the two groups of energy storage devices are connected with the micro-grid through separate power electronic interfaces, and a bidirectional energy storage converter is selected as the power electronic interface equipment for the grid-connected operation of the micro-grid and the power distribution network; in step S2, the micro-grid and the power distribution network are connected in series with a high-voltage circuit breaker, and a monitoring device is arranged to monitor the voltage, frequency and harmonic of the output electric energy of the micro-grid; when the voltage, frequency and harmonic of the output electric energy of the micro-grid do not meet the standard of the power distribution network, the high-voltage circuit breaker is disconnected from the micro-grid in time; S3: an electric energy detection device is arranged to monitor the electric energy storage capacity of the energy storage device, and the two groups of energy storage devices are connected with the new energy power generation equipment through a power switching structure one, and the two groups of energy storage devices are connected with the micro-grid through a power switching structure two; S4: the electric energy storage of the energy storage device is uploaded to the control center through the electric energy detection device; the two groups of energy storage devices comprise an energy storage device one and an energy storage device two; in the initial state, the energy storage device one is connected with the new energy power generation equipment to store electric energy, and the energy storage device two is disconnected from the new energy power generation equipment; when the electric energy storage capacity of the energy storage device one reaches a set value, the power switching structure one is actuated to disconnect the energy storage device one from the new energy power generation equipment, and the energy storage device two is connected with the new energy power generation equipment to store electric energy; S5: after the energy storage device one is disconnected from the new energy power generation equipment, a power generation mode is started, and the energy storage device one stably delivers electric energy to the micro-grid; at this time, the energy storage device two is in an energy storage state, and does not deliver electric energy to the micro-grid; when the residual electric energy of the energy storage device one is less than the set value, the power switching structure two is actuated to connect the energy storage device two with the micro-grid, and then the power switching structure one is actuated to connect the energy storage device one with the new energy power generation equipment after a time delay; the energy storage device two is disconnected from the new energy power generation equipment, and the energy storage device two starts the power generation mode; when the energy storage device two stably delivers electric energy to the micro-grid, the power switching structure two is actuated to disconnect the energy storage device one from the micro-grid, the energy storage device one is connected with the new energy power generation equipment to store electric energy, and the energy storage device two stably supplies electric energy.

2. The method of claim 1, wherein: The two groups of energy storage devices are flywheel storage system devices.

3. The method of claim 2, wherein: The electric energy detection device comprises a rotating speed sensor and a signal amplifier, and the rotating speed sensor is any one of an optical encoder and a Hall sensor.

4. The method of claim 1, wherein: The power switching structure one comprises an industrial-grade remote control relay A connected in series with a circuit between the energy storage device one and the new energy power generation equipment, and an industrial-grade remote control relay B connected in series with a circuit between the energy storage device two and the new energy power generation equipment; the power switching structure two comprises an industrial-grade remote control relay A1 connected in series with a circuit between the energy storage device one and the micro-grid, and an industrial-grade remote control relay B2 connected in series with a circuit between the energy storage device two and the micro-grid.

5. The method of claim 1, wherein: The new energy power generation equipment comprises any one of a wind power generation system and a photovoltaic power generation system.

6. The method of claim 3, wherein: The flywheel rotating speed standard of the energy storage device when the electric energy storage capacity reaches the set value is 30000 rpm to 60000 rpm, and the flywheel rotating speed standard of the energy storage device when the residual electric energy is insufficient is 600 rpm to 1200 rpm.

7. The method of claim 1, wherein: The high-voltage circuit breaker is a remote control high-voltage relay.