Zone area micro-grid reactive power autonomous method based on new energy grid connection

Abstract

According to the district micro-grid reactive power autonomous method based on new energy grid connection, the district micro-grid reactive power autonomous method is deployed in a district intelligent fusion terminal, and the district intelligent fusion terminal is connected with each piece of side end equipment in a district through different modes and collects operation data of the side end equipment. All the collected data are uploaded to a power distribution main station in a 5g mode; the district micro-grid reactive power autonomous method comprises a master station mode and an autonomous mode. According to the method, the safety production management level of the distribution network is improved, the manual calculation workload is greatly reduced, the labor intensity is reduced, the automation level and the working efficiency of relay protection work of a power dispatching center are improved, and the safety and the stability of a power grid are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid self-control, and in particular to a reactive power autonomy method of a microgrid in an area based on new energy grid connection. Background Art

[0002] With the continuous advancement of energy demand and environmental protection, more and more new energy sources, such as wind energy, solar energy, and hydropower, are being developed and utilized. The emergence of these new energy systems has enabled traditional energy systems to develop in the direction of intelligence and efficiency, and has promoted the development of smart grids. However, due to the instability, instantaneity, and randomness of new energy output, integrating new energy into the power system will lead to a series of technical problems. Among them, the reactive power problem is considered to be one of the most serious impacts of new energy on the power system. Due to the output changes and uncertainty of new energy, the reactive power control of microgrids is greatly challenged. Based on the above situation, in order to solve the problem of reactive power optimization of microgrids, this paper proposes a reactive power autonomy method for a microgrid in a substation under the grid connection of new energy.

[0003] Since 2017, State Grid Corporation of China has gradually promoted the construction of smart substations, and installed smart fusion terminals on the substation distribution transformer side. Therefore, with the smart fusion terminal as the core and the substation reactive power management device as the auxiliary, the substation microgrid voltage autonomy system is installed inside the smart fusion terminal. According to the substation information such as voltage, current, and new energy output power collected by the smart fusion terminal, the substation reactive power control strategy is sent to the reactive power management device. At the same time, according to the control information returned by the reactive power management device, the increase and decrease of distributed photovoltaic reactive power is controlled, and combined with the collected terminal user voltage data, the output voltage and reactive power compensation of the distribution substation are adjusted, thereby achieving terminal user voltage stability, accurate reactive power compensation of the distribution substation, reducing grid losses, and improving user power quality.

[0004] However, traditional voltage and reactive power integrated control is mainly implemented in substations at all levels, which has the following shortcomings: the substation control area is large, and the needs of users in each area cannot be taken into account at the same time; the capacity of a single capacitor group is too large, and operation adjustment is difficult, resulting in low voltage; capacitors need to be frequently switched on and off, and the transformer on-load tap-changing switch is raised and lowered, resulting in poor transient stability and voltage stability of the power grid. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and provide a reactive power autonomy method for a substation microgrid based on new energy grid connection, which improves the level of safe production management of distribution networks, greatly reduces the workload of manual calculations, reduces labor intensity, improves the automation level and work efficiency of relay protection work in the power dispatching center, and improves the safety and stability of the power grid.

[0006] In order to solve the above technical problems, the present invention provides a reactive power autonomy method for a microgrid in a substation area based on new energy grid connection.

[0007] In this method, the reactive power autonomy method of the substation microgrid is deployed in the substation intelligent fusion terminal. The substation intelligent fusion terminal connects to various edge devices in the substation in different ways and collects their operating data, and uploads all collected data to the distribution master station through 5G. The reactive power autonomy method of the substation microgrid includes two operating modes:

[0008] A. Master station mode: The fusion terminal receives control instructions from the master station. The reactive power autonomy method of the microgrid in the substation generates control instructions in the order of first regulating the reactive power management device and then regulating the photovoltaic output according to the instructions issued by the master station, the adjustable margin of the reactive power management device and the adjustable margin information of the photovoltaic device, and completes the reactive power management function;

[0009] B. Autonomous mode, the reactive power autonomy method of the substation microgrid generates a control strategy based on the collected substation equipment data, in the order of reactive power control device first and then photovoltaic device, to control the upper and lower limits of the substation outlet voltage and reactive power compensation.

[0010] Preferably, the method is installed in the reactive autonomous system of the microgrid in the substation, and the system is provided with an electrical detection and early warning module, and the intelligent fusion terminal of the module is connected to the photovoltaic controller, the reactive compensation device, and the intelligent circuit breaker respectively through HPLC; the microgrid reactive autonomous system is installed in the intelligent fusion terminal, and the message is sent to the opposite device according to the agreed modbus, mqtt, and 104 protocols, and the electrical quantity information of the photovoltaic inverter and the reactive management device is read in real time and sent to the data center, and the data includes three-phase voltage and current, active and reactive power, power factor, three-phase total harmonic distortion rate, reactive compensation capacitor switching status, and equipment failure alarm; the data center adopts a timed upload or a variable upload method to upload the above electrical quantities to the distribution master station.

[0011] Preferably, the parameter setting logic of the method is: the reactive power autonomy method of the substation microgrid in the substation intelligent fusion terminal obtains the parameters issued by the distribution master station from the data center; the parameters issued by the master station include the upper and lower limits of the strategic voltage regulation, the upper and lower limits of the strategic reactive compensation, and the reactive compensation device parameters; wherein, the upper and lower limits of the strategic voltage regulation and the upper and lower limits of the strategic reactive compensation have time marks, which divide the 24 hours of a day into several time periods. When the system runs to the marked time point, the microgrid voltage autonomy system will execute the parameters of the corresponding time period; the distribution master station refers to the collected user voltage data, and issues the time-divided voltage regulation threshold parameters according to the fluctuations of user voltage in different time periods.

[0012] Compared with the related art, the present invention has the following beneficial effects:

[0013] The present invention proposes a reactive power autonomy method for a substation microgrid based on new energy grid connection, which utilizes functions such as intelligent fusion terminal information collection, Internet of Things agent, edge computing, etc., assisted by reactive power management devices, photovoltaic controllers, photovoltaic inverters, smart meters and distribution master stations. A reactive power autonomy method for a substation microgrid is proposed, which uses the fusion terminal to issue control strategies to the reactive power management device, and uses the photovoltaic controller and photovoltaic inverter to add the reactive power of photovoltaic power generation to the reactive power control resources, thereby improving the level of safe production management of the distribution network, greatly reducing the workload of manual calculations, reducing labor intensity, improving the automation level and work efficiency of relay protection work in the power dispatching center, and improving the safety and stability of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a framework diagram of the reactive power autonomy method of the substation microgrid of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0016] The present invention provides a reactive power autonomy method for a microgrid in a substation area based on new energy grid connection, and the operation process is as follows:

[0017] The reactive power autonomy method of the substation microgrid is deployed in the substation intelligent fusion terminal. The substation intelligent fusion terminal connects to each edge device in the substation in different ways and collects its operation data, and uploads all the collected data to the distribution main station through 5G. There are two operating modes of the substation microgrid reactive autonomy method. One is the master station mode. The fusion terminal receives the control instructions from the master station. The substation microgrid reactive autonomy method generates control instructions in the order of prioritizing the reactive power management device and then adjusting the photovoltaic output according to the instructions issued by the master station, the adjustable margin of the reactive power management device and the adjustable margin of the photovoltaic device, and completes the reactive power management function; the second operating mode is the autonomous mode. In this mode, the substation microgrid reactive autonomy method generates a control strategy in the order of reactive power management device first and then photovoltaic device according to the collected substation equipment data, and controls the output voltage of the substation, the upper and lower limits of reactive power compensation, etc., so as to improve the power supply quality of end users.

[0018] The intelligent fusion terminal is connected to the photovoltaic controller, reactive power compensation device, and intelligent circuit breaker through HPLC. The intelligent fusion terminal is equipped with a microgrid reactive autonomous system. It sends messages to the end device according to the agreed modbus, mqtt, 104 and other protocols, reads the electrical quantity information of the photovoltaic inverter and reactive power management device in real time and sends it to the data center. The data includes three-phase voltage and current, active and reactive power, power factor, three-phase harmonic total distortion rate, reactive power compensation capacitor switching status, equipment fault alarm, etc. The data center sends the above electrical quantities to the distribution master station in a timed or variable manner, thereby realizing the node electrical quantity data collection of the intelligent distribution station area, the power supply quality alarm of the station area, and the operating status monitoring of the terminal equipment. At the same time, the distribution master station can extract the uploaded data for visual display.

[0019] The reactive power autonomy method of the microgrid in the substation intelligent fusion terminal obtains the parameters issued by the distribution master station from the data center. The parameters issued by the master station include the upper and lower limits of the strategy voltage regulation, the upper and lower limits of the strategy reactive compensation, and the parameters of the reactive compensation device. Among them, the upper and lower limits of the strategy voltage regulation and the upper and lower limits of the strategy reactive compensation have time marks, which can divide the 24 hours of a day into several time periods. When the system runs to the marked time point, the microgrid voltage autonomy system will execute the parameters of the corresponding time period. The distribution master station refers to the collected user voltage data and issues the time-divided voltage regulation threshold parameters for the fluctuation of user voltage in different time periods. For example, a certain substation is far away from the end user and there are many power supply users, resulting in a high voltage requirement at the outlet of the substation. At this time, through the time-divided parameter setting function, higher upper and lower voltage regulation thresholds can be set during the peak period of electricity consumption to increase the outlet voltage of the substation to ensure that the user voltage will not be low, and lower upper and lower voltage regulation thresholds can be set during the low period of electricity consumption to reduce the outlet voltage of the substation to avoid excessive voltage of the user. In this way, the user voltage can be maintained stable and the quality of electricity consumption can be guaranteed.

[0020] The key points of the present invention are: when the microgrid reactive autonomy system starts running, it first reads the parameters sent from the master station to the data center, and judges the operation mode entered by the microgrid reactive autonomy method according to the corresponding parameters; if the microgrid reactive autonomy method is in the master station mode, then the remote signaling and telemetry information of the photovoltaic inverter and the reactive power management device are read at a regular interval, and sent to the master station, waiting for the master station control command, and the terminal equipment is not actively controlled; if the microgrid reactive autonomy method is in the autonomous mode, then the microgrid voltage autonomy method reads the electrical quantity information of the substation after reading the remote signaling and telemetry information of the terminal equipment, combines the upper and lower limit parameters of voltage and reactive power, and uses the photovoltaic controller, photovoltaic inverter and reactive power management control device to comprehensively adjust the substation voltage and reactive power.

[0021] In the present invention, the intelligent fusion terminal in the substation area performs data aggregation and instruction forwarding of distributed photovoltaic and reactive power control devices through HPLC communication. Alternative solutions:

[0022] 1. Use RS485 line communication to directly connect the intelligent fusion terminal, photovoltaic inverter and reactive power control device;

[0023] 2. Use network cable communication to directly connect the intelligent fusion terminal, photovoltaic inverter and reactive power control device;

[0024] 3. Use 4G / 5G / micropower and other wireless communication methods to connect intelligent fusion terminals, photovoltaic inverters and reactive power control devices.

[0025] Finally, all the parts not described in the present invention adopt mature technical means in the prior art.

[0026] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A reactive power autonomy method for a microgrid in an area based on new energy grid connection, characterized by: The reactive power autonomy method of the substation microgrid is deployed in the substation intelligent fusion terminal. The substation intelligent fusion terminal connects to various edge devices in the substation in different ways and collects their operating data, and uploads all collected data to the distribution master station through 5G. The reactive power autonomy method of the substation microgrid includes two operating modes: A. Master station mode: The fusion terminal receives control instructions from the master station. The reactive power autonomy method of the microgrid in the substation generates control instructions in the order of first regulating the reactive power management device and then regulating the photovoltaic output according to the instructions issued by the master station, the adjustable margin of the reactive power management device and the adjustable margin information of the photovoltaic device, and completes the reactive power management function; B. Autonomous mode, the reactive power autonomy method of the substation microgrid generates a control strategy based on the collected substation equipment data, in the order of reactive power control device first and then photovoltaic device, to control the upper and lower limits of the substation outlet voltage and reactive power compensation.

2. According to claim 1, a method for reactive power autonomy of a microgrid in a substation area based on new energy grid connection is characterized by: The method is installed in the reactive power autonomous system of the microgrid in the substation area. The system is equipped with an electrical detection and early warning module. The intelligent fusion terminal of the module is connected to the photovoltaic controller, the reactive power compensation device and the intelligent circuit breaker through HPLC. The intelligent fusion terminal is equipped with a microgrid reactive autonomous system, which sends messages to the opposite device according to the agreed modbus, mqtt and 104 protocols, reads the electrical quantity information of the photovoltaic inverter and reactive power management device in real time and sends it to the data center. The data includes three-phase voltage and current, active and reactive power, power factor, three-phase total harmonic distortion rate, reactive compensation capacitor switching status, and equipment fault alarm; the data center sends the above electrical quantities to the distribution master station by scheduled or variable sending.

3. According to claim 1, a method for reactive power autonomy of a microgrid in a substation area based on new energy grid connection is characterized in that: The parameter setting logic of the method is as follows: the reactive power autonomy method of the substation microgrid in the substation intelligent fusion terminal obtains the parameters issued by the distribution master station from the data center; the parameters issued by the master station include the upper and lower limits of strategic voltage regulation, the upper and lower limits of strategic reactive compensation, and the parameters of the reactive compensation device; among them, the upper and lower limits of strategic voltage regulation and the upper and lower limits of strategic reactive compensation have time marks, which divide the 24 hours of a day into several time periods. When the system runs to the marked time point, the microgrid voltage autonomy system will execute the parameters of the corresponding time period; the distribution master station refers to the collected user voltage data, and issues the time-divided voltage regulation threshold parameters according to the fluctuations of user voltage in different time periods.

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