CN106786695A - Sodium-sulphur battery power station - Google Patents

Abstract

The present invention relates to a kind of sodium-sulphur battery power station, including sodium-sulfur battery energy storage device, energy conversion system, battery management system, Power Station Monitored Control System, energy storage device heap storage, power station basic platform, sodium-sulfur battery energy storage device includes some sodium sulphur energy-storage module groups, battery management system includes direct current administrative unit, battery management unit, Power Station Monitored Control System includes key-course on the spot, central control level, scheduling controlling layer, key-course includes power conversion subsystem monitoring module on the spot, battery management subsystem, on-site monitoring equipment, power information harvester, central control level includes collection control server, collection controlled switching system, collection control human-computer interaction device, scheduling controlling layer includes some scheduling controlling terminal devices, sodium sulphur energy-storage module group includes some sodium sulphur energy-storage module strings, sodium sulphur energy-storage module string includes some sodium sulphur energy-storage modules.The invention provides a kind of sodium-sulphur battery power station with practicality, directiveness, with good commercial application prospect.

Description

Sodium sulfur battery power station

technical field

The invention relates to a battery power station, in particular to a sodium-sulfur battery power station, which belongs to the field of energy storage power stations.

Background technique

Energy storage refers to the process of storing energy through a medium or device, using chemical or physical methods, and releasing it in a specific form of energy according to the needs of the application. Generally speaking, energy storage refers to energy storage for electrical energy. Power energy storage technology provides a package solution to achieve the goal of sustainable development of the power grid, solve the imbalance between power supply and demand, and improve the reliability of power supply. The use of large-scale energy storage devices can reduce and delay investment in power generation, transmission, transformation, and distribution equipment, improve the utilization rate of existing power equipment and power supply reliability, and reduce power generation coal consumption and power supply line losses. At the same time, the development of the power grid itself is also facing problems such as the gradual increase in peak-to-valley difference in power consumption, the increased risk of safe operation of the power grid after the scale of the power grid increases, the increased requirements for power quality in metropolitan power grids, and the new requirements for new energy grid-connected operation technologies. The construction of smart grids for these problems also puts forward urgent requirements for the development of electric energy storage technology. Among the key core technologies of the smart grid, energy storage technology started relatively late, and there are obvious deficiencies in technology maturity and industrialization research. It is still in its infancy in China and needs to be vigorously promoted. Energy storage is divided into three categories according to the energy storage medium: physical energy storage, chemical energy storage and other forms of energy storage. Physical energy storage mainly includes pumped water storage, compressed air energy storage, flywheel energy storage, etc. Chemical energy storage mainly includes energy storage in the form of lead-acid batteries, lithium batteries, flow batteries, sodium-sulfur batteries, nickel-cadmium batteries, etc. Other forms of energy storage include supercapacitors, superconducting electromagnetic energy storage, etc.

As society's demand for electricity and production continue to grow, the installed capacity, coverage area, and load peak-to-valley difference in the power grid continue to expand. Such a large amount of power demand puts forward higher requirements for the stability, security, and intelligence of the power grid. . Therefore, there is an urgent need for such a power storage system to be matched with it to balance the power load, improve equipment operation efficiency and economy, reduce or delay the investment in power construction, improve the ability to respond to sudden accidents in the power grid, and ensure the safety of power system operation. . More importantly, the electric energy storage system can "stitch" intermittent renewable energy together, improve the stability of the power system, and thus solve the bottleneck problem of the development of renewable energy. As a load balancing device and backup power source, electric energy storage system is also a key technology necessary for smart grid and distributed energy system, which is used to solve the problems of high failure rate, small system capacity and large load fluctuation.

Sodium-sulfur energy storage battery (hereinafter referred to as sodium-sulfur battery) is very suitable for power energy storage due to its advantages of large capacity, small size, high energy storage and conversion efficiency, long life, and no geographical restrictions. After comprehensive comparative analysis, sodium-sulfur battery is currently one of the energy storage methods with the highest energy density and power density, and is currently the only energy storage battery that is completely suitable for both power-type energy storage and energy-type energy storage. As a new member of the family of chemical power sources, sodium-sulfur batteries have received great attention and development in many countries in the world. Since sodium-sulfur batteries have a series of characteristics of high-energy batteries, since the late 1980s and early 1990s, foreign countries have focused on the development of sodium-sulfur batteries as applications in fixed occasions (such as power station energy storage), and their superiority has increasingly shown. Sodium-sulfur batteries have been successfully used in peak shaving and valley filling, emergency power supply, wind power and other renewable energy sources, and improving power quality. Sodium-sulfur battery technology and production process have been relatively mature, but the current engineering application of sodium-sulfur battery energy storage system lacks practical experience, and the charging and discharging operation characteristics, cycle operation characteristics, and series-parallel operation characteristics of sodium-sulfur battery energy storage systems are still lacking. Practical understanding, there is still a lack of guiding norms in the system design of grid access.

Contents of the invention

The sodium-sulfur battery power station of the invention discloses a new solution, provides a practical and instructive sodium-sulfur battery power station, and solves the problem of lack of practical solutions in the prior art.

The sodium-sulfur battery power station of the present invention includes a sodium-sulfur battery energy storage device, an energy conversion system, a battery management system, a power station monitoring system, an energy storage device stack, and a power station foundation platform, and the sodium-sulfur battery energy storage device includes several sodium-sulfur energy storage module groups The sodium-sulfur energy storage module group is connected to the grid bus through the energy conversion system. The battery management system includes a DC management unit and a battery management unit. The DC management unit is set in the combiner cabinet. The dispatching control layer, the local control layer is connected to the centralized control layer by communication, the centralized control layer is connected to the dispatching control layer by communication, and the local control layer includes the energy conversion subsystem monitoring module, the battery management subsystem, the on-site monitoring equipment, and the power information collection device , the centralized control layer includes a centralized control server, a centralized control switch, and a centralized control human-computer interaction device. The dispatching control layer includes a number of dispatching control terminal devices. The dispatching control terminal device includes a dispatching control server and a dispatching control workstation. The sodium-sulfur energy storage module group includes Several sodium-sulfur energy storage module strings, the sodium-sulfur energy storage module strings are connected to the energy conversion system through the confluence cabinet, the sodium-sulfur energy storage module strings include several sodium-sulfur energy storage modules, and the sodium-sulfur energy storage modules include sodium-sulfur battery modules, battery management unit, the sodium-sulfur energy storage module is installed in the energy storage device stack, and the energy storage device stack is set on the basic platform of the power station.

Further, the sodium-sulfur battery energy storage device of this solution includes sodium-sulfur energy storage module group A and sodium-sulfur energy storage module group B, and sodium-sulfur energy storage module group A includes sodium-sulfur energy storage module string A, sodium-sulfur energy storage module string B, sodium-sulfur energy storage module string A includes ten 5kW energy-type sodium-sulfur energy storage modules, sodium-sulfur energy storage module string B includes ten 5kW energy-type sodium-sulfur energy storage modules, sodium-sulfur energy storage module group B includes sodium-sulfur Energy storage module string C, sodium-sulfur energy storage module string D, sodium-sulfur energy storage module string C includes 10 5kW power type sodium-sulfur energy storage modules, sodium-sulfur energy storage module string D includes 2 25kW power type sodium-sulfur energy storage modules module. The storage bins of energy storage devices include stacker group A and stacker group B. Stacker group A includes two 5kW module stacks arranged side by side back to back. The 5kW module stacker includes three 5kW module stacks. Group B includes three 5kW module stacks and one 25kW module stack. The 5kW module stack is a two-story "Tian"-shaped cabinet structure. There are four 5kW For the storage space of the module, the 25kW module stacking warehouse is a two-story "Day"-shaped warehouse structure. There are two 25kW module warehouses in the upper and lower two-story "Day"-shaped warehouse structure.

Further, the energy conversion system of this solution includes a dual-mode energy storage converter and a number of bidirectional DC converters. The inverter sides of the above-mentioned bidirectional DC converters are connected in parallel to the DC side of the dual-mode energy storage converter. The AC side of the energy storage converter is connected to the grid bus, and the sodium-sulfur energy storage module string is connected to the dual-mode energy storage converter through a bidirectional DC converter. The dual-mode energy storage converter includes a DC-side EMI filter, a three-phase PWM rectifier, a transformer, and an AC-side BMI filter. The dual-mode energy storage converter converts the DC output from the bidirectional DC converter into a three-phase AC input to the grid or To supply power to the electric load, the dual-mode energy storage converter converts the alternating current in the grid into direct current, which is stepped down by the bidirectional direct current converter and then input to the sodium-sulfur energy storage module string. Bidirectional DC converter includes input DC circuit breaker QF1, output DC circuit breaker QF2, input DC contactor KA1, output DC contactor KA3, input capacitor C1, output capacitor C2, DC EMI filter, pre-charging resistor R1, pre-charging contact KA2, reactor L1, half-bridge IGBT module, fuse FU1, the bidirectional DC converter will step down the electric energy on the inverter side and input the sodium-sulfur energy storage module string, and the bidirectional DC converter will connect the sodium-sulfur energy storage module string After the boosted electric energy is input into the dual-mode energy storage converter through the inverter side.

Further, the battery management unit of this solution includes a battery voltage detection module, a battery temperature detection control module, and the DC management unit includes a loop voltage detection module, a loop current detection module, a battery management unit control module, and a data communication interface. The interface transmits function signals to the upper computer and the energy conversion system. The DC management unit receives operation instructions and setting information from the upper computer monitoring system through the data communication interface. The DC management unit transmits the above operation instructions and settings to the battery management unit through the battery management unit control module. information. The DC management unit communicates with the battery management unit through the RS485 bus, and the DC management unit communicates with the host computer monitoring system and the energy conversion system through MODBUS.

Further, the energy conversion subsystem monitoring module of this solution includes a converter voltage monitoring module, a converter current monitoring module, a converter temperature monitoring module, and a converter switch monitoring module. The current monitoring module of the converter collects the current signal of the converter, the temperature monitoring module of the converter collects the temperature signal of the converter, and the switch monitoring module of the converter monitors the switch of the converter state.

Further, the energy storage device bin of this solution includes an environmental monitoring device, and the environmental monitoring device includes a temperature sensor, a humidity sensor, and an exhaust fan. The temperature sensor and the humidity sensor are arranged in the energy storage device bin, and the exhaust fan is arranged in the energy storage device On the top of the bin, the environmental monitoring device activates the exhaust fan according to the comparison result of the temperature sensor and the humidity sensor detection value being greater than the set value, and the exhaust fan discharges the heat and moisture in the storage bin of the energy storage device through air flow.

Furthermore, the storage bin of the energy storage device in this scheme also includes a fire alarm control system, which includes a main controller, a smoke sensor, a smoke removal filter, an audible and visual alarm device, and a backup battery power supply. The main controller is located in the secondary In the equipment room, the smoke sensor is installed in the storage bin of the energy storage device. The smoke removal filter includes a smoke exhaust pipe and a closed filter chamber, and a spray filter is installed in the closed filter chamber. Trigger the sound and light alarm device and the exhaust fan, and the exhaust fan discharges the smoke through the smoke exhaust pipe into the closed filter chamber for filtration.

Further, the basic platform of the power station in this scheme includes the outdoor storage platform and the equipment indoor space. The storage storage device is installed on the outdoor storage platform. The equipment indoor space is equipped with a confluence cabinet, an energy conversion system, and a grid AC There is a firewall between the busbar, the indoor space of the equipment and the outdoor storage platform of the storage warehouse, and a fence device is installed around the storage outdoor storage platform. The ground level of the foundation platform of the power station is higher than the ground level around the foundation platform of the power station. A drainage pipe system is arranged inside the foundation platform of the power station. Drainage facilities to the foundation around the foundation platform of the power station.

Furthermore, the roof of the energy storage device warehouse of this scheme is a "herringbone" structure, and the edge of the roof is provided with a rain gutter structure, and the rain gutter structure and the drainage pipe system are connected through pipelines, and the precipitation falling into the roof of the warehouse After entering the rain gutter structure, it is discharged from the foundation platform of the power station through the drainage pipe system.

Further, the basic platform of the power station in this program also includes a remote viewing technical defense system, which includes electronic fences, camera devices, access control systems, sound and light alarms, network switches, and monitoring terminals. The device collects and stores on-site video information through the camera, and the upper computer of the remote viewing technology defense system can access the on-site video information through the monitoring terminal at any time.

The sodium-sulfur battery power station of the invention provides a practical and instructive sodium-sulfur battery power station, and has good commercial application prospects.

Description of drawings

Figure 1 is a schematic diagram of the principle of a sodium-sulfur battery power station in this scheme.

Fig. 2 is a schematic diagram of the principle of the sodium-sulfur energy storage subsystem.

FIG. 3 is a schematic diagram of the principle of a bidirectional DC converter.

Fig. 4 is a schematic diagram of the principle of a dual-mode energy storage converter.

Fig. 5 is a schematic diagram of the principle of the power station monitoring system.

Fig. 6 is a schematic diagram of a sodium-sulfur battery power station installed on the basic platform of the power station.

Among them, PCS is an energy conversion system, BMS is a battery management system, BMU is a battery management unit, and DMU is a DC management unit.

detailed description

The main equipment of the energy storage power station includes battery modules, combiner cabinets, PCS and other various control equipment. The sodium-sulfur battery is characterized by high-temperature operation. It needs an incubator to maintain its working temperature. It has low requirements on the external environment temperature and can be used in various indoor and outdoor installation environments. Batteries are energy storage bodies. Sodium-sulfur batteries operate in high-temperature environments. Safety issues have always been one of the most important issues for sodium-sulfur batteries. In addition to adding intrinsically safe designs to the battery body and modules, the design of safety protection module stacks is also One of the indispensable security means. An isolation protection plate is installed between each module to effectively prevent the failure of individual batteries from affecting the safe operation of other equipment. The battery modules used in the power station include two types of 5kW and 25kW. Based on the design principles of saving land, rationally utilizing land, and improving land utilization, the modules are placed in stacks. There are 4 5kW or 2 25kW battery modules in a stack. When installing, use the method of upper and lower layers. The power station is divided into 2 groups with a total of 4 circuits. The 4 circuit stacks are arranged side by side. A space of about 3 meters needs to be reserved between the 2 groups for operation. The sodium-sulfur battery is at about 300°C during normal operation. Considering safety reasons, a firewall or guardrail is built around the warehouse (reserving a safe space). The battery module is cubic. The size of the 5kW module is 92cm×81cm×105cm and the weight is about 1000kg. The size of the 25kW module is 2020cm×1510cm×1100cm and the weight is about 3500kg. There is a BMU box on the module, and a certain operating space needs to be reserved. The installation of the stacker and the battery module requires a large amount of operating space, and after the installation is completed, the reserved space cannot be fully utilized, such as stacking. Indoors, it will cause a lot of waste of space. The outdoor installation space is large, and the operation is relatively convenient. It is convenient to use various large-scale equipment, and it is also convenient for the entry and exit of transport vehicles. Therefore, the outdoor method is selected for the storage bin installation.

The battery modules are stacked in layers. In a circuit, the battery modules are connected in series, and the number of modules varies according to the scale of the power station. The stacking of modules adopts a two-layer structure and is arranged in a back-to-back manner, that is, the backs of the two circuits are arranged side by side. This arrangement can greatly improve the utilization of space and avoid reserving operations before and after each string of stacks The space waste caused by the safe space. An iron plate is installed between each module to avoid the possibility that a battery fire will spread to other modules in extreme cases.

In addition to battery modules and stacking bins, the power station is also composed of confluence cabinets, PCS, station power supply and metering cabinets, UPS control panels and other equipment. The combiner cabinet is an electrical device that is directly connected to the battery module. Each circuit is equipped with a combiner cabinet, and the DC trunk lines of all modules are collected in the combiner cabinet. In order to avoid excessive voltage drop on the line due to too long cables during high-current discharge, the distance between the combiner cabinet and the stack must be minimized in design. The size of the confluence cabinet is 800cm×800cm×2000cm, and it can be installed indoors or outdoors. PCS, station power supply and metering cabinet, and UPS control screen are all 800cm×800cm×2000cm in size, requiring frequent operations by staff, and there are touch screens and electrical components installed on the surface of the equipment, which have high requirements for the environment. It is not suitable for outdoor installation, so choose indoor installation.

In order to prevent excessive rainfall in rainy days, the top of the stack adopts a triangular slope design, so that no rainwater will remain on the top of the stack when it rains. Rain eaves are designed on the edge of the sloping surface above the warehouse. When it rains, the rainwater above the warehouse will flow into the rain eaves, along the rain eaves, and finally be discharged to the outside of the guardrail or firewall through pipes, preventing rainwater from being directly poured into the site. , causing the water level at the site to be too high. In some areas, when it enters the rainy season, the rainfall is relatively heavy. In order to ensure that there will be no water accumulation on the site of the power station, the ground of the power station is designed with a slope. The ground of the power station is 20cm higher than the road next to it. One end close to the road has a smaller horizontal slope, and the other end has a larger slope. Rainwater can flow along the ground of the power station to the road next to it, and the rainwater will be retained from the road to other places. For the convenience of wiring, there is a 2.28m×5.72m equipment foundation under the warehouse, and drainage pipes are arranged in the foundation, so that the water level inside the foundation will not be too high due to rain.

The battery module is at a high temperature of 300°C during operation, and the weather in some areas is relatively hot in summer, which will cause the temperature in the stack to be too high and affect the operation of electrical equipment in the stack. In order to solve this problem, an environmental monitoring device and an exhaust fan are installed on the top of the stacker. A temperature sensor is installed in the device to monitor the temperature in the stacker in real time. When the temperature is higher than the set value, the exhaust fan starts automatically, and the stacker The heat will be discharged to the outside of the stacker with the air, and the outside air will enter the stacker from the vents under the door panel of the stacker or the equipment foundation, so that the air in the stacker and the outside air form a cycle to take away the heat to achieve The purpose of cooling the warehouse. The environmental monitoring device is also equipped with a humidity sensor. When the humidity in the stack is higher than the set value, the exhaust fan can also be activated to circulate the air in the stack with the outside air and take away the humid air in the stack.

The safe operation of the power station is the prerequisite for the operation of the power station, including the safety of personnel and equipment. Safety protection measures are divided into three categories: electrical protection measures, physical protection measures and safety system protection measures. In terms of electrical protection, the energy storage capacity of the power station is 200kW, so according to the "QGDW480-2010 Technical Regulations on Connecting Distributed Power to the Grid", the overcurrent tripping protection of the air circuit breaker is adopted, and no additional protection device is required. In order to ensure the safety of personnel, when the operator performs electrical operations, a high-voltage insulating pad will be placed underneath. The temperature of the sodium-sulfur battery is about 300°C during normal operation, and firewalls and fences are set up around the power station. The firewall is set to be 1 meter away from the storage bin. Considering the operating range of equipment installation, the on-site firewall is 2 meters away from the storage bin. On the other side without a firewall, a fence is set up 3 meters away from the warehouse to ensure the safety of personnel in the event of a fire. If a fire breaks out in the power station, water cannot be used for fire fighting, and yellow sand and fire extinguishers are equipped inside the power station. Once a fire occurs in the power station, the battery module emits a large amount of smoke after it catches fire, which will touch the smoke sensor on the environmental monitoring device, and the exhaust fan in the stacker will start at the same time, and the smoke and volatile harmful substances will enter the filter along with the pipeline, and the spray pump will start at the same time , After the water flow enters the filter, water mist is formed, and volatile harmful substances are integrated into the water, avoiding damage to the surrounding environment. The air conditioning and ventilation system of the substation is linked with the fire alarm system. The fire alarm control system is composed of the main controller, various detectors, manual alarm buttons, alarm bells, cables and other equipment. When a fire occurs, the detector sends the fire signal to the main controller, and the main controller can display the fire alarm. The time and place of the occurrence, and an audible and visual alarm signal will be issued. The main controller is located in the secondary equipment room, which is responsible for the monitoring of the fire protection system of the whole station. Install air sampling smoke detectors in the secondary equipment room and converter room, and lay linear constant temperature detectors in the cable trench, and at the same time send fire alarm signals to the monitoring system in the station for remote transmission. The AC 220V power supply used by the fire alarm control device is directly powered by an uninterruptible power supply, and the device itself has a battery as a backup power source for the AC power supply.

The monitoring system is connected to the internal network of the power company through optical fiber, and cameras are installed in the warehouse and the control room, covering every corner of the demonstration power station. The video captured by the camera is stored in the monitoring system cabinet in the control room. The power company can remotely check the operation data of the power station at any time, and can read the video shot by the camera to check the situation of the demonstration power station in real time. Once the power station is abnormal, you can know the specific situation at the first time and take urgent measures. There is a GPRS device in the combiner cabinet, and the basic data of the battery module sent by the DMU can be viewed remotely through a computer with a client installed and connected to the network, so as to grasp the operation status of the power station at any time. A set of remote viewing technology defense system is configured in the power station, and the remote viewing technology defense equipment only involves the scope of the energy storage power station. The remote viewing technical defense system consists of electronic fence, camera, infrared alarm, access control system, sound and light alarm, connecting cable, monitoring screen cabinet, embedded hard disk video recorder, liquid crystal display, alarm host, integrated power supply, network switch, monitoring terminal and other equipment.

The power station mainly consists of three parts: sodium-sulfur energy storage subsystem, energy conversion subsystem and monitoring system. The sodium-sulfur energy storage subsystem mainly includes sodium-sulfur energy storage battery modules, battery management systems, confluence cabinets, stacking bins and other electrical equipment, which mainly realize the operation control and online detection of sodium-sulfur batteries. The energy conversion subsystem includes bidirectional direct current conversion (DC/DC) and dual-mode energy storage conversion (AC/DC), which realizes bidirectional energy transfer between the DC battery of the battery energy storage system and the AC grid. The monitoring system is a computer-based process control and scheduling automation system, mainly composed of on-site workstations and servers.

The sodium-sulfur energy storage subsystem is the most important subsystem in the power station, including sodium-sulfur battery modules, battery management systems (BMS) and confluence cabinets. It is composed of sodium-sulfur battery energy storage modules, battery management subsystems, confluence cabinets and stackers. Constitute an energy storage module stack. The sodium-sulfur energy storage subsystem consists of 2 sets of 4-series sodium-sulfur energy storage modules, connected to 2 PCSs, each module is equipped with a DC management unit DMU and a confluence cabinet in series, and each module is equipped with a battery management unit Unit BMU. The first group consists of 20 5kW energy type MCN-5E sodium-sulfur battery modules, which are divided into 2 strings, with 10 sets in each string, connected to the grid or load after being connected to the PCSA. The second group is 10 sets of 5kW power type MCN-5P sodium-sulfur battery modules to form the first string, and two sets of 25kW power type MCN-25P type sodium-sulfur battery modules to form the second string, which are respectively connected to the PCSB and then connected to the grid or load. The external dimensions of the 5kW battery module are 907mm×986mm×1038mm, and the external dimensions of the 25kW module are 2120mm×1630mm×1100mm.

The sodium-sulfur battery management system (BMS) is mainly composed of two parts: the DC management unit (DMU) and the battery management unit (BMU). The BMU is mainly responsible for the detection of the voltage and temperature of the battery module, and the operation control of the module temperature. For current detection, the battery status is analyzed and judged according to the voltage and temperature of the battery module detected by the BMU, and when a fault occurs, a fault alarm signal and a disable signal are sent to the host computer and the energy conversion system (PCS), and the DMU is also responsible for receiving Monitor system operation instructions and setting information, and send the received instructions and information to the BMU for execution. The communication between DMU and BMU is through RS485 bus, and the communication between DMU and upper computer monitoring system and PCS is through MODBUS.

The BMU is installed on the battery module, and its main functions and technical parameters are as follows:

⑴Detect battery or battery string voltage, range: 0~18V; measurement accuracy: ±0.020V, each channel is collected independently, without interfering with each other;

(2) Measure the total output voltage of the module, and the measurement accuracy is ±0.1FS%mV;

(3) Continuous temperature inspection, range: 0-500°C, temperature control accuracy ±5°C. The default factory temperature rise setting; the change of time and temperature can be intelligently set;

⑷The temperature control adopts PWM pulse width adjustment, and the optical isolation controls the solid state relay to adjust the heating power;

(5) The monitoring module switches to the automatic temperature compensation operation mode when it is in the charging and discharging state;

⑹Communicate with DMU through external RS485/CAN bus, the communication rate is 250kb/s, and send battery data, battery status and alarm information;

⑺There are 2 switch output control functions;

⑻There are 6 switch input monitoring functions;

⑼ Body fault self-test function;

⑽ Immunity level: IEC Ⅳ level.

The DMU is installed in the combiner cabinet. DMU is the upper-level management system of BMU, which can manage up to 12 BMUs. The main technical parameters and functions are as follows:

⑴Sodium-sulfur energy storage module string total voltage measurement, range: 0-640V, accuracy: ±0.1V;

⑵ Charge and discharge current measurement, range: 0～±1000A, test accuracy: ±1.5A (depending on sensor accuracy);

⑶Completely independent RS485 and CAN/LAN interface;

(4) The bus can communicate with up to 12 BMU modules to read battery voltage and temperature information;

⑸By two-way communication between CAN and PCS, it can control the charge and discharge of the DC branch;

⑹The LAN interface communicates with the system monitoring PC through the TCP/IP protocol, reports the branch battery voltage, temperature and other information, and receives commands from the control platform;

⑺SOC estimation and SOH, SOC estimation accuracy is less than 10%;

⑻Provide 14 channels of digital input monitoring function;

⑼Provide 6 switch output control functions;

⑽Fault diagnosis and online alarm (voltage, current, temperature, and SOC);

⑾Realize real-time monitoring of battery operating status: including charging process control commands, discharging process control commands, battery pack temperature control, and battery complete management;

⑿ Realize battery fault diagnosis and safety protection: including battery fault diagnosis and failure control instructions;

⒀With self-test and self-diagnosis functions: it can diagnose and deal with various BMU faults;

⒁Battery safety: prevent battery overcharge and overdischarge; monitor battery operating status in real time, and send prompt information such as maintenance request, repair request, and disable request in time;

⒂ After the battery has been used for a period of time, it is necessary to check the capacity of the battery, and the capacity of the used battery can be tested through the capacity inspection mode;

⒃Fault and maintenance status upload: During the operation of the system, if the BMU fails or needs to be repaired, the fault and maintenance status upload function of the device itself can be used to upload the device’s own fault and maintenance signals to the energy storage module stack monitoring system.

The combiner cabinet is an important part of the sodium-sulfur energy storage subsystem. It collects the DC cables of all battery modules in the circuit, connects the energy conversion system through the combiner cabinet, and controls the service/decommissioning of the battery modules. In addition, the combiner cabinet is also responsible for the distribution and control of the working power and auxiliary power of the battery modules in the loop. The DMU installed in the combiner cabinet realizes the operation control and management of the BMU, and collects data from the BMU for processing and transmission. When the battery module fails, it sends out an alarm and disable signal.

The battery modules are installed in the stack. The stack is divided into upper and lower layers and installed back to back. The first and second circuits are installed together for the first group, and the third and fourth circuits are installed together for the second group. Each stacker can hold 4 sets of 5kW battery modules, which are arranged in upper and lower layers, and the module numbers are defined clockwise from the bottom left of the stacker. There are two 25kW battery modules in this power station, which are installed in a stacking group and installed separately.

In addition to serving as a carrier for battery modules, the stacker also has the function of protecting and regulating the environment of battery modules. Its main functions are as follows:

⑴The warehouse adopts modular and standardized design, and is transported by parts and installed on site;

⑵Basic stacking bins can be assembled back-to-back or parallel or vertical into multi-position stacking bins. A protective isolation plate can be set between each module, and a fixing device needs to be set after the module is in place;

(3) Ventilation openings and smoke (temperature and humidity) monitoring devices are installed in appropriate positions for each basic storage bin, and axial flow fans are installed on the upper part for forced ventilation of the basic storage bin;

⑷Stack protection level is not less than IP54.

⑸Stacks can be installed directly on the concrete foundation with a flatness of less than 2mm, or on the channel steel foundation reserved in the electrical room.

An important part of the battery energy storage system is the power conversion system (Power Conversion System). The two-way energy transfer between the battery module of the sodium-sulfur energy storage subsystem and the AC grid can be realized through PCS, the charge and discharge management of the battery module can be realized through the control strategy, the tracking of the load power of the grid side, and the charge and discharge power of the battery energy storage system can be realized. control, control of the grid-side voltage in the off-grid operation mode, etc. The PCS is mainly composed of a bidirectional direct current converter (DC/DC) and a dual-mode energy storage converter (AC/DC) to realize bidirectional energy transfer between the sodium-sulfur energy storage subsystem and the AC grid. The function of the DC/DC bidirectional DC converter is to raise the voltage of the loop to a voltage level suitable for the AC/DC dual-mode energy storage converter. One loop uses a 50kW bidirectional DC converter (DC/DC), and the converter consists of The three modules work in parallel and alternately, and the three modules share the charge and discharge power of the battery module in the circuit equally. The inverter side of the DC/DC bidirectional DC converter is connected in parallel to the DC side of the AC/DC converter.

In a bidirectional DC/DC converter, input and output DC circuit breakers QF1, QF2, input and output DC contactors KA1, KA3, input and output capacitors C1, C2, DC EMI, pre-charging resistor R1, pre-charging contactor KA2, reactance Device L1, H-bridge IGBT module, fuse FU1. When the bidirectional Buck/Boost converter (boost-boost converter) works in the forward direction, T1 and D2 work together, and the energy AC/DC inverter flows to the battery, from left to right, in Buck step-down mode. When T1 is turned on, the voltage on C2 side is applied to diodes D1, L1 and output capacitor C1, so D2 is turned off. At this time, the voltage applied to L is U1>U2, so the inductor current increases linearly and the energy is stored in L in the form of magnetic field energy, and at the same time, it charges the battery. When T1 is turned off, the inductor current continues to flow through D2, the inductor current decreases linearly, and the energy stored in L is transferred to C1. When working in reverse, T2 and D1 work together, and energy flows from the battery to the AC/DC inverter, from right to left, in boost mode. When T2 is turned on, all of C1 is added to the inductance, the inductance current increases linearly, the electric energy is stored in L in the form of magnetic field energy, and the diode D1 is cut off. When T2 is turned off, the inductor current flows to the output side through D1, and the energy stored on C1 and L1 is transferred to C2, that is, to charge C2. At this time, the voltage applied to the inductor is U2-U1 is less than zero, so the inductor current is linear decrease. In the process of DC/DC conversion, PI control with voltage and current double closed-loop is adopted. The feedback signal Uo of the actual output voltage is compared with the given value U _dref of the output voltage, and the difference is generated through the PI link to generate the given current signal I _dref of the inner loop (current loop), and I _dref is then compared with the feedback value I of the inductor current Compared with _dl , a PWM control signal is finally generated, and then the switch state of the IGBT in the DC/DC main circuit is controlled to realize a stable voltage output.

The AC/DC dual-mode energy storage converter, as the interface between the grid and the sodium-sulfur energy storage subsystem, is an important part of the energy storage system. Its main function is to convert the direct current output from the DC/DC bidirectional DC converter into three The phase-to-phase alternating current is input to the grid or supplies power to the load, and the alternating current in the grid can also be converted into direct current through a DC/DC bidirectional direct current converter and then stored in the sodium-sulfur battery module to realize bidirectional energy between the sodium-sulfur battery and the grid. flow, and can realize grid-connected and off-grid operation control. The function design of PCS energy storage converter is as follows:

⑴ DC side polarity reverse protection, DC side over and under voltage protection, DC side over current protection, AC side over current protection, short circuit protection, AC side over and under voltage protection, AC side over and under frequency protection, overheat protection, surge Protect;

⑵Limited voltage discharge, constant power discharge, constant current discharge and other functions;

(3) Island detection function;

⑷ Control strategy for seamless switching of micro-grid system on-grid and off-grid based on sodium-sulfur energy storage subsystem;

⑸Active and reactive control functions;

⑹ High-rate discharge function combined with the characteristics of the sodium-sulfur battery itself;

(7) The AC side of the AC/DC dual-mode energy storage converter can be directly connected to off-grid loads and charging equipment in V/F off-grid operation mode, and connected to the grid to charge the battery in P/Q mode;

(8) The DC/DC bidirectional DC converter can be compatible with various configurations and models of sodium-sulfur battery modules;

(9) Multi-machine parallel operation control function on the DC side and the AC side;

⑽Man-machine interface and communication function.

AC/DC dual-mode converters and DC/DC converters are basically the same in hardware structure, mainly including power modules and reactors, contactors and circuit breakers, EMI filters, controllers, isolation transformers, UPS and other components composition.

The monitoring system is a computer-based process control and scheduling automation system. It can monitor the distributed power generation, energy storage devices and load status inside the microgrid. According to the power supply and compliance characteristics, optimize the control of its internal distributed power generation, energy storage devices and loads, realize the safe and stable operation of the microgrid, and improve the energy utilization efficiency of the microgrid. The monitoring system is mainly composed of distributed generation monitoring, energy storage device monitoring, load monitoring, security monitoring and power quality monitoring. The design of the microgrid system adopts a hierarchical control method, which can be logically divided into three layers, namely, the local control layer, the centralized control layer, and the power grid dispatching layer. The power grid dispatching layer is the microgrid and distribution network dispatching system, which coordinates and dispatches the microgrid system from the perspective of the safety and economic operation of the entire power grid. The centralized control layer is the core part of the entire micro-grid system, which centrally manages distributed power sources, energy storage devices and various loads, completes the monitoring and control of the micro-grid, and optimizes the control strategy in real time according to the operation of the micro-grid to achieve grid connection, The smooth transition of off-grid and outage is responsible for realizing the optimization of micro-grid operation during grid-connected operation, and adjusting distributed power generation output and power consumption of various loads during off-grid operation to achieve stable and safe operation of micro-grid. The local control layer consists of protection equipment and local controllers of the microgrid system. The on-site controller of the micro-grid completes the primary adjustment of the frequency and voltage of the distributed power generation, and the on-site protection equipment completes the rapid protection of the micro-grid system failure.

The monitoring system mainly collects and summarizes the information of various subsystems, such as the sodium-sulfur energy storage subsystem, the energy conversion subsystem, and the safety monitoring platform, etc., analyzes and judges the collected information, and helps the operating personnel to make decisions. Optimized control scheme. The monitoring system has data acquisition function, data processing function, control operation function, fault alarm function, event processing function, human-computer interaction function, etc.

⑴Data collection function

Collect the operating state parameters of distributed power generation and energy storage devices, including at least telemetry signals such as group terminal voltage, group terminal current, state of charge, temperature, etc., as well as remote signaling signals such as switch status, accident signals, and abnormal signals. Collect telemetry signals such as voltage, current, and temperature of the converter, as well as remote signaling signals such as switch status, accident signals, and abnormal signals. Collect remote measurement signals such as voltage, current, phase, frequency, active power, reactive power, power factor, active energy, and reactive energy of the distribution network interface, as well as switch status, accident signals, and abnormal signals.

⑵Data processing function

Perform calculation and analysis on the collected data, cross-line alarm, rationality check, etc., and store relevant data.

⑶ control operation function

Realize on-off control for the corresponding switchgear of the energy storage system, and control the charging and discharging state of the energy storage device.

⑷Fault alarm function

It has functions such as alarm confirmation and clearing of accident signals and abnormal signals, alarm query, custom alarm level, alarm statistical analysis, alarm information storage, etc., and can be realized through graphics, voice, text, printing, etc.

⑸Event processing function

It can realize the functions of sequence recording, location and local fault information query of events.

⑹Human-computer interaction function

Screen display function. It can display the electrical structure diagram of the energy storage system, the charging and discharging curve diagram and the real-time data of the system, and provide graphical display such as data pie chart and histogram according to the needs, and can provide the sequence display of the main events. Interactive operation function. Send remote control, check time, etc., realize manual position, alarm confirmation, listing and other operations on the man-machine interface, edit and modify database, graphics and other information. Report management function. Automatically generate reports for energy storage system data, abnormal and accident information, operation records, etc., edit, store, and query reports, and have functions such as scheduled printing and call printing.

⑺Interconnection with automated information system

It is interconnected with dispatching automation system, power distribution automation system, marketing management system and other related systems to realize data and information exchange.

There are 30 5kW modules and 2 25kW modules in the power station, of which:

(1) 20 sets of MCN-5E modules, configured with 5 groups of stacking bins, forming a 100kW sodium-sulfur energy storage module string group, divided into 2 lines to connect to the DC/DC DC circuit of PCS-A-1 and PCS-A-2 grid-connected devices.

(2) 10 sets of MCN-5P modules, configured with 3 groups of stacking bins, forming a 50kW sodium-sulfur energy storage module string, connected to the PCS-B-1 grid-connected device DC/DC direct current circuit.

(3) 2 sets of MCN-25P modules, equipped with a group of 25kW module stacks, forming a 50kW sodium-sulfur energy storage module string, connected to the PCS-B-2 grid-connected device DC/DC DC circuit.

The location of the energy storage subsystem installation area, the confluence cabinet is placed indoors, and a fire door for maintenance access is installed on the open wall. The installation position of the combiner cabinet is close to the module stack, which is convenient for grouping and maintenance of the module strings, and prevents misoperation.

Unless otherwise specified, the electrical equipment, circuits, modules, and electronic components involved in the above schemes can choose common designs and schemes in the field according to their specific functions, and can also choose other designs and schemes according to actual needs.

The sodium-sulfur battery power station of this scheme starts from the overall design of the demonstration power station, designs the function and structure of the PCS energy conversion system, specifies the technical parameters of the bidirectional DC converter and the dual-mode energy storage converter, and designs the energy storage monitoring system The system structure and hierarchical structure stipulate the basic functions and extended functions of the energy storage monitoring system body, put forward the performance index of the energy storage system connected to the distribution network monitoring system, optimize the communication structure of the system, and carry out the module stacking method design. Based on the above contents and characteristics, the sodium-sulfur battery power station of this scheme has outstanding substantive features and significant progress.

The sodium-sulfur battery power station of this scheme is not limited to the content disclosed in the specific implementation. The technical schemes in the examples can be extended based on the understanding of those skilled in the art. Those skilled in the art can make simple replacements based on this scheme combined with common knowledge The program also falls within the scope of this program.

Claims (10)

1. sodium-sulphur battery power station, it is characterized in that including sodium-sulfur battery energy storage device, energy conversion system, battery management system, electricity Stand monitoring system, energy storage device heap storage, power station basic platform, the sodium-sulfur battery energy storage device includes some sodium sulphur energy-storage modules Group, the sodium sulphur energy-storage module group is connected by the energy conversion system with power network bus, and the battery management system includes Direct current administrative unit, battery management unit, the direct current administrative unit is arranged on confluxes in cabinet, and the Power Station Monitored Control System includes On the spot key-course, central control level, scheduling controlling layer, the key-course on the spot is communicated to connect with the central control level, described Central control level and the scheduling controlling layer communication connection, the key-course on the spot include power conversion subsystem monitoring module, Battery management subsystem, on-site monitoring equipment, power information harvester, the central control level include collection control server, collection Controlled switching system, collection control human-computer interaction device, the scheduling controlling layer include some scheduling controlling terminal devices, the scheduling controlling Terminal device includes scheduling controlling server, scheduling controlling work station, and the sodium sulphur energy-storage module group includes some sodium sulphur energy storage Module string, the sodium sulphur energy-storage module string is connected by the cabinet that confluxes with the energy conversion system, the sodium sulphur energy-storage module string Including some sodium sulphur energy-storage modules, the sodium sulphur energy-storage module includes sodium-sulfur battery module, the battery management unit, the sodium Sulphur energy-storage module is arranged in the energy storage device heap storage, and the energy storage device heap storage is arranged on the power station basic platform.

2. sodium-sulphur battery power station according to claim 1, it is characterised in that the sodium-sulfur battery energy storage device includes sodium sulphur Energy-storage module group first, sodium sulphur energy-storage module group second, the sodium sulphur energy-storage module group first includes that sodium sulphur energy-storage module string A, sodium sulphur are stored up Energy module string B, the sodium sulphur energy-storage module string A include 10 5kW energy type sodium sulphur energy-storage modules, the sodium sulphur energy-storage module string B includes 10 5kW energy type sodium sulphur energy-storage modules, and the sodium sulphur energy-storage module group second includes that sodium sulphur energy-storage module string C, sodium sulphur are stored up Energy module string D, the sodium sulphur energy-storage module string C include 10 5kW power-type sodium sulphur energy-storage modules, the sodium sulphur energy-storage module string D includes 2 25kW power-type sodium sulphur energy-storage modules；The energy storage device heap storage includes heap storage group first, heap storage group second, the heap storage Group first includes the 2 5kW modules heap storages row's first being arranged side by side back-to-back, and the 5kW modules heap storage row first includes 3 5kW modules Heap storage, the heap storage group second includes the heap storage of 3 5kW modules, 1 25kW module heap storage, and the 5kW modules heap storage is upper and lower two-layer Sphere of movements for the elephants shape storehouse cabinet structure, 4 positions in storehouse of 5kW modules, the 25kW are provided with the upper and lower two-layer sphere of movements for the elephants shape storehouse cabinet structure Module heap storage is that upper and lower two-layer " says " font storehouse cabinet structure, and the upper and lower two-layer " is said " and 2 25kW are provided with font storehouse cabinet structure The position in storehouse of module.

3. sodium-sulphur battery power station according to claim 1, it is characterised in that the energy conversion system includes double mode storage Energy current transformer, some two-way DC converters, the inverter side of some two-way DC converters are connected in parallel to the bimodulus The DC side of formula energy accumulation current converter, the AC of the double mode energy accumulation current converter accesses power network bus, the sodium sulphur energy storage mould Block string is connected by the two-way DC converter with the double mode energy accumulation current converter；The double mode energy accumulation current converter includes DC side electromagnetic interface filter, Three-Phase PWM Rectifier, transformer, AC BMI wave filters, the double mode energy accumulation current converter is by institute The direct current for stating two-way DC converter output is converted into three-phase alternating current input power network or is powered to power load, the bimodulus Alternating current in power network is converted into direct current and is input into the sodium after the two-way DC converter is depressured by formula energy accumulation current converter Sulphur energy-storage module string；The two-way DC converter includes that input direct-current circuit breaker Q F1, output dc circuit breaker QF2, input are straight Stream contactor KA1, output D.C. contactor KA3, input capacitor C1, output capacitor C2, direct current electromagnetic interface filter, precharge Resistance R1, pre-charge contactor KA2, reactor L1, half-bridge IGBT module, fuse FU1, the two-way DC converter will be inverse Become the electric energy step-down input sodium sulphur energy-storage module string of device side, the two-way DC converter is by the sodium sulphur energy-storage module string Electric energy boosting after the double mode energy accumulation current converter is input into by inverter side.

4. sodium-sulphur battery power station according to claim 1, it is characterised in that the battery management unit includes cell voltage Detection module, battery temperature detection control module, the direct current administrative unit include that loop voltage detection module, loop current are examined Module, battery management unit control module, data communication interface are surveyed, the direct current administrative unit passes through the data communication interface To host computer, energy conversion system transmitting function signal, the direct current administrative unit is by the data communication interface from upper Machine monitoring system receives operating instruction, configuration information, and the direct current administrative unit is by the battery management unit control module The operating instruction, configuration information are transmitted to the battery management unit；The direct current administrative unit and the battery management list Unit is passed through by RS485 bus communications, the direct current administrative unit with the Monitor Computer Control System, energy conversion system MODBUS communicates.

5. sodium-sulphur battery power station according to claim 1, it is characterised in that the power conversion subsystem monitoring module bag Include current transformer voltage monitoring module, current transformer current monitoring module, current transformer temperature monitoring module, converter switches monitoring mould Block, the current transformer voltage monitoring module gathers DC side, the voltage signal of AC of the current transformer, the current transformer electricity Flow monitoring module gathers the current signal of the current transformer, and the current transformer temperature monitoring module gathers the temperature of the current transformer Signal, the converter switches monitoring module monitors the on off state of the current transformer.

6. sodium-sulphur battery power station according to claim 1, it is characterised in that the energy storage device heap storage includes environmental monitoring Device, the environmental monitoring installation includes temperature sensor, humidity sensor, exhaust blower, the temperature sensor, humidity sensor Device is located in the energy storage device heap storage, and the exhaust blower is located at the top of the energy storage device heap storage, the environmental monitoring dress Put and the air draft is started more than the comparison result of setting value with the detected value of the humidity sensor according to the temperature sensor Machine, the exhaust blower derives the heat in the energy storage device heap storage, moisture by air flow.

7. sodium-sulphur battery power station according to claim 6, it is characterised in that the energy storage device heap storage also includes fire report Alert control system, the fire alarm control system includes master controller, Smoke Sensor, smoke abatement filter, sound and light alarm dress Put, standby battery power supply, the master controller is located in secondary equipped chamber, and the Smoke Sensor is located at the energy storage device In heap storage, the smoke abatement filter includes smoke discharging pipe, closed filtering chamber, and spray is provided with the closed filtering chamber Filter, the master controller triggers the acoustic-optic alarm, the air draft according to the alarm signal of the Smoke Sensor Smog is entered and filtered in the closed filtering chamber by machine, the exhaust blower by the smoke discharging pipe.

8. sodium-sulphur battery power station according to claim 1, it is characterised in that the power station basic platform is included outside heap storage room Platform for placing, the equipment interior space, platform for placing is provided with the energy storage device heap storage outside the heap storage room, in the canyon The cabinet that confluxes, energy conversion system, power network ac bus are provided with space, are put outside the equipment interior space and the heap storage room Fire wall is provided between platform, fence apparatus are equipped with around platform for placing outside the heap storage room；The ground of the power station basic platform Face level height is laid with draining higher than the ground level around the power station basic platform in the power station basic platform Piping, the entrance of the Sewer System is located in the basis of the energy storage device heap storage, and institute is led in the outlet of the Sewer System State the pumping equipment of ground around the basic platform of power station.

9. sodium-sulphur battery power station according to claim 8, it is characterised in that the silo roof of the energy storage device heap storage is " people " Character form structure, the edge of the silo roof is provided with rain gutter construction, and the rain gutter construction is connected with the Sewer System by pipeline It is logical, the Sewer System discharge power station basis is passed through after the precipitation remittance rain gutter construction for falling into the silo roof flat Platform.

10. sodium-sulphur battery power station according to claim 8, it is characterised in that the power station basic platform also includes remote viewing Technical precaution system, the remote viewing technical precaution system includes that fence, camera head, gate control system, audible-visual annunciator, networking exchange Machine, monitor terminal, the camera head include some cameras, and the camera head is gathered by the camera, storage is existing Field video information, the host computer of the remote viewing technical precaution system has access to the live video information by the monitor terminal at any time.