CN203312828U - Microgrid coordinated control system - Google Patents

Abstract

The utility model provides a micro-grid coordination control system, the micro-grid coordination controller of the micro-grid coordination control system is respectively connected to the distributed power supply terminal, the micro-grid protection measurement and control device and the intelligent electric energy meter through the Ethernet; the micro-grid coordination The controller monitors the distributed power supply terminal in real time, and sends control instructions to the distributed power supply terminal and the micro-grid protection measurement and control device according to the distributed power supply monitoring information, so as to realize the optimal operation of the micro-grid. Compared with the prior art, the micro-grid coordination control system provided by the utility model realizes the maintenance-free and practical operation of the micro-grid connected to various distributed power sources.

Description

A Microgrid Coordinated Control System

technical field

The utility model belongs to the field of electric power systems, and in particular relates to a micro-grid coordination control system.

Background technique

At present, in the field of power system, the scale of the power grid is continuously expanding, and it has gradually developed into a super-large interconnected network system with centralized power generation and long-distance power transmission. However, with the continuous increase of long-distance power transmission, the dependence of the receiving power grid on external power continues to increase, the stability and security of power grid operation tend to decline, and it is difficult to meet diversified power supply needs. At the same time, problems such as the gradual depletion of global conventional energy sources and environmental pollution have become increasingly prominent, and environmentally friendly, efficient and flexible distributed power generation is widely favored. Distributed power generation has the characteristics of flexible location and decentralization, which perfectly adapts to the decentralized power demand and resource distribution, and delays the huge investment required for the upgrading of the transmission and distribution network; it is also a backup with the large power grid, which also improves the reliability of power supply .

Distributed power generation mainly includes various types of renewable energy power generation systems (wind energy, solar energy, biomass energy, etc.), and its clean and environmentally friendly characteristics meet the requirements of low-carbon economic development. However, the access of a single distributed power source to the grid has brought certain impacts on the grid due to its own characteristics such as intermittency, volatility, and randomness. The disturbance ability is poor, and the abandonment of light and wind is very serious, which leads to the decrease of the annual utilization hours of distributed power supply, which affects the economics of distributed power supply investment.

In order to coordinate the contradiction between the large power grid and distributed power, and fully exploit the value and benefits brought by distributed power to the power grid and users, the concept of microgrid (Microgrid) is proposed and continuously developed. The United States Association for Electrical Reliability Technology Measures Solutions defines the microgrid as follows: a microgrid is a system composed of loads and micro power sources, which can provide power and heat at the same time; the power supply inside the microgrid is mainly composed of power electronics. The device is responsible for energy conversion and provides necessary control; the microgrid is a single controllable unit compared to the external large grid, and at the same time meets the user's requirements for power quality, power supply reliability and security. The EU microgrid project defines the microgrid as follows: using primary energy, using a micro-distributed power generation system, which is divided into three types: uncontrollable, partially controllable and fully controllable, and can be combined with cold, heat and electricity; equipped with Energy storage devices; energy conversion and control using power electronics. In short, the microgrid has the characteristics of independence, flexibility, interaction, and economy. It is a brand-new power supply method and one of the main development directions of the future power grid.

Therefore, it is very important to provide a micro-grid coordinated control system for distributed power sources based on a typical micro-grid operating structure composed of multiple distributed power sources.

Contents of the invention

In order to meet the needs of the prior art, the utility model provides a micro-grid coordination control system, the micro-grid coordination control system includes a micro-grid coordination controller connected to a distributed power supply terminal through Ethernet; the micro-grid coordination The controller is respectively connected to the micro-grid protection measurement and control device and the smart energy meter through Ethernet;

The micro-grid coordination controller monitors the distributed power supply terminal in real time, and sends control instructions to the distributed power supply terminal and the micro-grid protection measurement and control device according to the distributed power supply monitoring information, so as to realize the optimal operation of the micro-grid.

Preferably, the smart energy meter is connected to the concentrator through the communication interface RS485 and then connected to the microgrid coordination controller;

Preferably, the micro-grid coordination controller includes a digital input module, a digital output module, an analog measurement module, an Ethernet expansion module, a power supply module and a man-machine interface module connected to the CPU module; the CPU module is used for Perform logic control, communication protocol processing, and configuration management on the microgrid coordination control system;

Preferably, the distributed power supply terminal includes a wind power generation terminal, a photovoltaic power generation terminal, a fuel cell power generation terminal, an energy storage terminal and a V2G terminal; The current signal and the power signal are sent to the micro-grid coordination controller, and the control instructions issued by the micro-grid coordination controller are received; The input and withdrawal control commands and power control commands sent by the PCS, the fuel cell PCS and the V2G converter PCS; the operating status signals include grid-connected status signals, grid-connected/off-grid switching status signals, off-grid status signals, and off-grid/grid-connected Switch state signal Four kinds of running state signals;

Preferably, the micro-grid protection measurement and control device includes an overcurrent protection unit, an overvoltage protection unit, an overfrequency protection unit, an undervoltage protection unit, an underfrequency protection unit, a synchronous closing protection unit, a reverse power protection unit, and a circuit breaker remote control Unit and circuit breaker remote signaling control unit.

The beneficial effects of the utility model are:

1. In the technical solution of the utility model, the energy storage terminal improves the stability of the microgrid system during operation and realizes seamless switching of important loads;

2. In the technical solution of the utility model, the human-machine interface module includes a large-screen liquid crystal display and a touch screen input, which makes the operation of the micro-grid coordination controller simpler and faster;

3. In the technical solution of the utility model, Ethernet is used as the communication method, which has the advantages of good openness, high transmission rate and low cost;

4. A micro-grid coordination control system provided by the utility model realizes maintenance-free and practical operation of micro-grids connected to various distributed power sources.

Description of drawings

Below in conjunction with accompanying drawing, the utility model is further described.

Figure 1 is a schematic structural diagram of a micro-grid coordinated control system provided by the utility model;

Figure 2 is: a connection diagram of a micro-grid coordinated control system provided by the utility model;

Fig. 3 is a schematic diagram of the structure of the microgrid coordination controller.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

Fig. 1 and Fig. 2 have shown a kind of microgrid coordination control system structural diagram provided by the present invention; Distributed power supply terminal, microgrid protection measurement and control device and smart electric energy meter are respectively connected with described microgrid coordination controller through Ethernet; The micro-grid coordination controller monitors the distributed power supply terminal in real time, and sends control instructions to the distributed power supply terminal and the micro-grid protection measurement and control device according to the distributed power supply monitoring information, so as to realize the optimal operation of the micro-grid;

Distributed power terminals include wind power generation terminals, photovoltaic power generation terminals, fuel cell power generation terminals, energy storage terminals and V2G terminals; execution instructions include converting currents to photovoltaic inverters, wind turbine inverters, energy storage PCS, fuel cell PCS and V2G The switching control command and power control command sent by the controller PCS; the distributed power terminal sends the collected distributed power running status signal, voltage signal, current signal and power signal to the micro-grid coordination controller, and receives the micro-grid coordination control The control command issued by the controller; the operating status signal includes four operating status signals: grid-connected status signal, grid-connected/off-grid switching status signal, off-grid status signal, and off-grid switching status signal;

The smart energy meter is connected to the concentrator through the communication interface RS485 and then connected to the micro-grid coordination controller to realize the power metering function of the metering point; the micro-grid protection measurement and control device includes an over-current protection unit, an over-voltage protection unit, and an over-frequency protection unit. unit, undervoltage protection unit, underfrequency protection unit, synchronous closing protection unit, reverse power protection unit, circuit breaker remote control unit and circuit breaker remote signaling control unit; the overcurrent protection unit, overvoltage protection unit, overfrequency protection The unit, undervoltage protection unit, underfrequency protection unit, synchronous closing protection unit and reverse power protection unit perform overcurrent protection, overvoltage protection, overfrequency protection, undervoltage protection, underfrequency protection, synchronous Closing protection and reverse power protection;

Figure 3 shows a schematic diagram of the structure of the micro-grid coordination controller; the micro-grid coordination controller includes a digital input module, a digital output module, an analog measurement module, an Ethernet expansion module, a power supply module and a man-machine interface connected to the CPU module module; the CPU module is used for logic control, communication protocol processing and configuration management of the micro-grid coordinated control system; the Ethernet expansion module realizes the expansion of the Ethernet network interface, and is used to realize the access of the communication system based on Ethernet and realize the coordinated control of the micro-grid The information interaction between the distributed power supply terminal or the smart energy meter; the human-machine interface module includes a large-screen LCD display and a touch screen input, which can observe the operating status and operating data of the micro-grid coordination control system, set parameters, and display micro-grid in real time. Network running status.

The specific embodiment of the microgrid coordination control system provided by the present invention is as follows:

The distributed power terminal includes a 189kW photovoltaic power generation system, a 6kW wind power generation system, a 10kW fuel cell power generation system, a set of 100kW battery energy storage system, and a 30kW V2G device control system; The total load capacity is about 1000kVA; the photovoltaic power generation system consists of one 125kW three-phase grid-connected inverter, two 30kW three-phase inverters and one 4kW three-phase inverter; the wind power generation system consists of six 1kW single-phase grid-connected inverter; the fuel cell power generation system consists of a 10kW three-phase grid-connected inverter;

The micro-grid coordinated control system adopts the master-slave control strategy mode; ①: When running off-grid, the battery energy storage system is the main power source for the micro-grid operation, using VF operation mode (Volt Frequency), and other distributed power sources are slave power sources, using PQ operation mode; the fuel cell power generation system provides electric energy to the load; the photovoltaic system and wind power generation system operate normally according to the voltage/frequency reference value provided by the battery energy storage system; V2G device control system does not participate in off-grid system power regulation;

②: When the off-grid operation is converted to grid-connected operation, the micro-grid coordination controller tracks the main grid voltage and the micro-grid voltage to realize simultaneous input; the main power supply (100kW battery energy storage system) is based on the grid-connected switch PCC ( Point of Common Coupling) state switching operation mode; that is, after the PCC is closed, the main power supply immediately switches to the PQ operation mode according to the PCC state;

③: During grid-connected operation, the grid provides voltage/frequency reference values, and other distributed power sources adopt PQ operation mode; the fuel cell power generation system does not work, and it is used as power support in case of emergency;

④: When grid-connected operation is converted to off-grid operation, the micro-grid coordination controller sends a trip command to the controllable load and the load that can be shed after receiving the off-grid switching signal to disconnect it from the micro-grid. At the same time, the main power supply (100kW battery Energy storage system) adopts the VF operation mode to establish the voltage and frequency reference value of the microgrid system, and then adjust the output of the distributed power supply, switch the load, realize the uninterrupted power supply of the sensitive load, and finally realize the stability of the voltage frequency within a reasonable range .

Finally, it should be noted that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Claims (5)

1. A micro-grid coordination control system, the micro-grid coordination control system includes a micro-grid coordination controller connected to a distributed power supply terminal through an Ethernet, it is characterized in that the micro-grid coordination controller is connected to a distributed power supply terminal through an Ethernet respectively The micro-grid protection measurement and control device is connected to the smart energy meter; The micro-grid coordination controller monitors the distributed power supply terminal in real time, and sends control instructions to the distributed power supply terminal and the micro-grid protection measurement and control device according to the distributed power supply monitoring information, so as to realize the optimal operation of the micro-grid. 2. A micro-grid coordination control system according to claim 1, wherein the smart energy meter is connected to the concentrator through the communication interface RS485 and then connected to the micro-grid coordination controller. 3. A kind of microgrid coordination control system as claimed in claim 1, is characterized in that, described microgrid coordination controller comprises the digital quantity input module that links to each other with CPU module, digital quantity output module, analog quantity measurement module, Ethernet A network expansion module, a power supply module and a man-machine interface module; the CPU module is used for logic control, communication protocol processing and configuration management of the micro-grid coordination control system. 4. A micro-grid coordinated control system according to claim 1, wherein the distributed power supply terminals include wind power generation terminals, photovoltaic power generation terminals, fuel cell power generation terminals, energy storage terminals and V2G terminals; The distributed power supply terminal sends the collected operating status signal, voltage signal, current signal and power signal of the distributed power supply to the micro-grid coordination controller, and receives the control instruction issued by the micro-grid coordination controller; The control instructions include switching control instructions and power control instructions sent to photovoltaic inverters, wind turbine inverters, energy storage PCS, fuel cell PCS and V2G converter PCS; the operating status signals include grid-connected status signals , On/off-grid switching status signal, off-grid status signal, and off-grid switching status signal on four operating status signals. 5. A microgrid coordinated control system as claimed in claim 1, wherein the microgrid protection measurement and control device includes an overcurrent protection unit, an overvoltage protection unit, an overfrequency protection unit, an undervoltage protection unit, an undervoltage protection unit, and an undervoltage protection unit. Frequency protection unit, synchronous closing protection unit, reverse power protection unit, circuit breaker remote control unit and circuit breaker remote signaling control unit.

Images