CN101728835A - Battery power energy storing device for smoothing output power of wind power generation - Google Patents

Abstract

The invention discloses a battery electric energy storage device for smoothing the output power of wind power generation, in particular to a battery electric energy storage system for smoothing the output power of wind power generation. A battery electric energy storage device for smoothing the output power of wind power generation, including an energy storage battery pack and a monitoring system), the energy storage battery pack and the output line of the wind power system are connected in parallel to an AC bus, and it is characterized in that the energy storage battery pack and the AC A power distribution device is connected between the busbars, and a power protection device is connected to the monitoring system. The invention coordinates the output power of wind power generation through the energy storage device, which not only effectively reduces the impact and impact on the grid when wind power is connected to the grid, but also improves the consistency between the output power of wind power and the prediction, and ensures the reliability of power supply. It also reduces the reserve capacity of the power system, improves the economy of the power system operation, and improves the ability of the power system to accept wind power.

Description

A battery electric energy storage device for smoothing the output power of wind power generation

technical field

The invention relates to a wind power generation energy storage system, in particular to a battery power storage system that smoothly outputs wind power generation power.

Background technique

As a clean and renewable energy, wind energy has been paid more and more attention by countries all over the world. China's wind energy reserves are large and widely distributed. The wind energy reserves on land alone are about 253 million kilowatts. In recent years, China's grid-connected wind power has developed rapidly. Due to the randomness and intermittent nature of wind energy, the output of wind turbines fluctuates frequently, and the reliability of wind farm output is also poor. If the proportion of wind power is too large, the pressure on frequency regulation and peak regulation of the power grid will increase, and the long-distance power transmission of the power grid will increase. The technical requirements and operating costs of electricity have increased dramatically. Therefore, the large-scale grid connection of wind farms also brings some new problems to the operation of the power system:

(1) The randomness and uncontrollability of wind power bring new challenges to power system planning and stable operation;

(2) The fluctuation characteristics of wind power and grid load are difficult to be consistent, which makes the peak regulation problem of the power grid more prominent, and puts forward higher requirements for peak regulation capacity and response speed;

(3) Due to changes in wind speed, wind turbines are likely to cause grid voltage and power fluctuations, as well as reactive voltage control and power quality problems brought about by them.

The current energy storage technology in the power system provides a new way to solve some existing problems in the power supply chain (fuel, power generation, transmission, distribution, and power consumption) and to achieve sustainable development of the power grid. Energy technology can effectively alleviate the contradiction between power supply and demand, improve power grid security and stability, improve power supply quality, and promote the utilization and development of renewable energy.

Contents of the invention

In order to solve the problem of short-term fluctuations in wind power generation power in the prior art, the present invention provides a battery power energy storage device that can smooth the output power of wind power generation. It includes an energy storage battery pack and a monitoring system. The energy storage battery pack is connected in parallel with the output line of the wind power system on an AC bus. It is characterized in that a power distribution device is connected between the energy storage battery pack and the AC bus bar, and the monitoring system is connected with power protection. device.

Another preferred mode of the present invention: the energy storage battery pack includes multiple parallel and/or series sub-battery packs, and the sub-battery pack includes multiple parallel and/or series-connected single cells.

Another preferred mode of the present invention: the single battery includes a flow battery, a sodium-sulfur battery, and a lithium-ion battery, and the batteries in each sub-battery group are of the same type, and the flow battery is connected with cold water for temperature regulation of the electrolyte As for the unit, the sodium-sulfur battery is connected with a heating power supply to ensure its internal temperature, and the lithium-ion battery is connected with a temperature alarm and a smoke sensor.

Another preferred mode of the present invention: the energy storage battery pack includes a capacity expansion interface and a communication interface.

Another preferred mode of the present invention: a converter is connected between the energy storage battery pack and the power distribution device.

Another preferred mode of the present invention: there are multiple converters and they are respectively connected to each sub-battery group.

Another preferred mode of the present invention: the converter is an AD/DC conversion module and/or a DC/DC conversion module.

Another preferred mode of the present invention: the power protection device is composed of a UPS power supply, and the power distribution device is a step-up box-type transformer.

Another preferred mode of the present invention: the sub-battery pack is equipped with a low-voltage relay protection device, including the following protection functions: overload protection, short-circuit protection, over-temperature protection, low-frequency protection, under-voltage protection, low-voltage protection, Balance protection, high frequency protection and phase sequence protection, grounding protection and other functions.

The invention coordinates the output power of wind power generation through the energy storage device, which not only effectively reduces the impact and impact on the grid when wind power is connected to the grid, but also improves the consistency between the output power of wind power and the prediction, ensuring the reliability of power supply. It also reduces the reserve capacity of the power system, improves the economy of the power system operation, and improves the ability of the power system to accept wind power. It lays the foundation for the impact of grid-connected wind farms on the power grid and corresponding countermeasures, the orderly development of grid-connected wind power, and the extensive application of energy storage in renewable power generation. A variety of different types of single batteries can be integrated and used, the converter can be used to ensure the voltage balance between the output voltage and the AC bus, and the use of the power protection device can always be used by the control system to control the use of the energy storage battery pack.

Description of drawings

Fig. 1 schematic diagram of the connection of the energy storage device of the present invention

Detailed ways

This energy storage device is mainly used to smooth the short-term (less than tens of minutes) fluctuation of the wind farm, or cooperate with the auxiliary output according to the predicted output power curve of the wind farm, so that the power output of the wind power system is close to the previous prediction, and the power output of the wind power system is improved. Reliability and consistency capabilities, the energy storage device can also carry out various combination experiments with wind turbines or wind power clusters, and consider the reactive power adjustment requirements of wind turbines.

As shown in Figure 1, the energy storage battery pack 1 of the energy storage device and the output line of the wind power system 5 are connected in parallel to an AC bus 4, and a power distribution device 6 is installed between the energy storage battery pack and the AC bus. For the pressure box transformer, the monitoring system 2 adjusts the output power of the wind power system smoothly by calling the power output of the energy storage device.

According to the characteristics of the energy storage battery, the energy storage battery group is further divided into multiple sub-battery groups, and each sub-battery group is equipped with a high-voltage switch. According to the different switching modes of the high-voltage switch group, the energy storage device and the wind turbine are on the same AC bus. , can form sub-battery packs and wind turbines for independent combination, and can also form a combination of the entire energy storage device with wind turbines and/or wind power clusters. Each sub-battery group 8 is equipped with a 380V low-voltage relay and a converter 7. The converter is composed of an AC/DC conversion module and a DC/DC conversion module. The AC-side AC/DC conversion module adopts a three-phase voltage source rectifier. Realize the bidirectional active rectification function, because the current of the energy storage device is required to have bidirectional mobility in its main circuit, so that the AC/DC conversion module can work in different states, so the controllable four-quadrant operation of the AC and DC sides is adopted. For the converter device, when the rectifier absorbs energy from the grid, it operates in the rectification state; on the contrary, when the rectifier transmits energy to the grid, the rectifier works in the active reverse state.

Since the DC bus voltage after rectification is about 600V, and the voltage of the single battery is relatively low, generally between 200V and 600V after being connected in series, some sub-battery packs need a DC/DC conversion module for voltage adjustment, and the DC side adopts bidirectional The topological structure of the DC/DC conversion module realizes the DC step-down and boost functions, and the main circuit of the bidirectional DC/DC conversion module realizes Buck step-down or Boost step-up mode.

The sub-batteries in each energy storage battery pack can be connected together in parallel or in series, or both ways can coexist. Each sub-battery can be classified according to the type of the single battery. The individual batteries in the battery pack can also be connected together in parallel and/or in series. The types of individual batteries include flow batteries, sodium-sulfur batteries, lithium-ion batteries, etc. In order to ensure the normal operation of various types of batteries, According to the different characteristics of various types of batteries, it is necessary to provide battery maintenance systems and protection systems. For flow batteries, it is equipped with chillers to adjust the temperature of the electrolyte. For sodium-sulfur batteries, it is equipped with a heating power supply to ensure its internal temperature. For The lithium-ion battery is equipped with alarm systems such as temperature alarm and smoke sensor. At the same time, the monitoring system 2 can realize the measurement and reporting of parameters such as current, voltage, SOC, and internal resistance of the single battery.

In order to ensure the safe operation of each sub-battery group, various low-voltage relay protection devices are installed in each sub-battery group, mainly with the following protection functions: overload protection, short-circuit protection, over-temperature protection, low-frequency protection, under-voltage protection, low-voltage protection , Phase unbalance protection, high frequency protection and phase sequence protection, grounding protection and other functions.

In order to ensure that the energy storage device can adapt to the grid connection of more wind power in the future, an expansion interface 9 is left on the energy storage device. When the energy storage device cannot adapt to the development of the power grid, it only needs to be connected to one or more sub-batteries. Achieve capacity growth.

The energy storage device is equipped with a number of different communication interfaces. The communication interface is connected to the monitoring system of the entire energy storage device, and provides various current data of the energy storage device to the monitoring system. These data include actual power generation, capacity, line status, current , Active power, reactive power, power coefficient and average value, automatically or manually control the power distribution switchgear through PLC. Through the collected data, the monitoring system realizes functions such as power output adjustment of the energy storage device, battery system management, real-time data sampling of wind turbine power generation, data upload, communication protocol conversion, calculation of AC and DC current command values required for converter control, and other functions. Control signals for transformer tap changers and circuit breakers that control energy storage devices.

In order to ensure that the monitoring system manages and controls the energy storage device under any circumstances, a power protection device 3 composed of multiple UPS power supplies is equipped.

Claims (9)

1. A battery electric energy storage device for smoothing the output power of wind power generation, comprising an energy storage battery pack (1) and a monitoring system (2), the energy storage battery pack and the output line of the wind power system (5) are connected in parallel to an AC busbar (4 ), characterized in that a power distribution device (6) is connected between the energy storage battery pack and the AC busbar, and the monitoring system (2) is connected with a power protection device (3). 2. The battery electric energy storage device according to claim 1, characterized in that, the energy storage battery group includes a plurality of parallel and/or series sub-battery groups (8), and the sub-battery group includes a plurality of parallel-connected and/or single cells in series. 3. The battery power energy storage device according to claim 2, wherein the single battery includes a liquid flow battery, a sodium-sulfur battery, and a lithium-ion battery, and the batteries in each sub-battery group are of the same type, and the liquid The flow battery is connected with a chiller for temperature regulation of the electrolyte, the sodium-sulfur battery is connected with a heating power supply to ensure its internal temperature, and the lithium-ion battery is connected with a temperature alarm and a smoke sensor. 4. The battery electric energy storage device according to claim 1, characterized in that, the energy storage battery pack includes a capacity expansion interface (9) and a communication interface. 5. The battery electric energy storage device according to claim 1, wherein a converter is connected between the energy storage battery pack and the power distribution device. 6. The battery electric energy storage device according to claim 5, characterized in that there are multiple converters (7) and are respectively connected to each sub-battery group. 7. The battery power energy storage device according to claim 6, wherein the converter is an AD/DC conversion module and/or a DC/DC conversion module. 8. The battery power energy storage device according to claim 1, characterized in that, the power guarantee device (3) is composed of a UPS power supply, and the power distribution device is a step-up box-type transformer. 9. The battery power energy storage device according to claim 1, wherein the sub-battery pack is equipped with a low-voltage relay protection device, which mainly has the following protection functions: overload protection, short-circuit protection, over-temperature protection, low-frequency Protection, undervoltage protection, low voltage protection, phase unbalance protection, high frequency protection and phase sequence protection, grounding protection and other functions.