CN210899205U - Distributed energy storage access terminal - Google Patents
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- CN210899205U CN210899205U CN201921824532.1U CN201921824532U CN210899205U CN 210899205 U CN210899205 U CN 210899205U CN 201921824532 U CN201921824532 U CN 201921824532U CN 210899205 U CN210899205 U CN 210899205U
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Abstract
The application discloses distributed energy storage access terminal includes: the CPU module, the alternating current sampling module, the direct current sampling module and the input-output module carry out information interaction through an internal bus; the CPU module comprises a main control CPU core and an auxiliary CPU core which are used for carrying out interaction of shared data through a shared memory; the main control CPU core is used for calculating the operation parameters of the energy storage device and carrying out corresponding logic control according to an operation control optimization strategy and algorithm based on the operation data of the energy storage access terminal according to a received control instruction of the remote master station, and carrying out coordination control optimization on the energy storage device; or responding to a control instruction of the remote master station to perform aggregation control on the energy storage device; and the auxiliary CPU core is used for carrying out communication management and protocol conversion on the energy storage access terminal. The distributed energy storage access terminal solves the technical problems that a single distributed energy storage system in the prior art is small in capacity and single in function.
Description
Technical Field
The application relates to the technical field of power system energy storage, in particular to a distributed energy storage access terminal.
Background
New energy sources represented by wind power, solar power generation and the like have intermittency, volatility and randomness, and large-scale consumption of the new energy sources becomes a worldwide problem. The energy storage technology is a key technology for improving the capacity of a power system for absorbing new energy. The energy storage can realize the migration of energy in time and space, and based on a flexible operation control technology, the energy storage can play a diversified role in the aspects of peak regulation, frequency modulation, blockage relieving, voltage supporting and reactive power control, emergency standby failure and the like in the operation of a power system. In recent years, the electrochemical energy storage technology is rapidly developed, the industrial scale is continuously enlarged, the cost is rapidly reduced, and related policies are continuously provided at the national level, so that the energy storage technology innovation, the energy storage equipment development and popularization and application are supported, and good conditions are created for promoting the energy storage technology in the power system.
In a large number of existing energy storage systems, information management of the existing energy storage systems is usually implemented by a communication manager or a local energy management system that can communicate with a communication master station or a cloud platform in real time, and the communication manager or the local energy management system is connected with the communication master station or the cloud platform and the like in an upward direction and is connected with an energy storage converter, a battery management system, an auxiliary unit and the like in each distributed energy storage system in a downward direction through a switch or other communication connection forms and the like. The communication management system is mainly equipment derived from the field of substation automation application, is mainly used for communication link management of various equipment, mainly aims at collecting and sorting operation data of each distributed energy storage system and then transmitting the operation data to a remote master station, and often does not have a coordination optimization control function. The current distributed energy storage is widely applied, but the capacity of a single distributed energy storage system is small, the function is single, if on the basis of information management, aggregation and coordination optimization control of the distributed energy storage system are realized, the diversified application of the distributed energy storage system is facilitated, and the utilization efficiency of energy storage resources is improved.
SUMMERY OF THE UTILITY MODEL
The application provides a distributed energy storage access terminal, which is used for carrying out data calculation and implementing a current optimal control mode based on an optimal control strategy and algorithm and acquired operation control data of an energy storage system so as to improve the equipment utilization rate and application value of the energy storage system and solve the technical problems of small capacity and single function of a single distributed energy storage system in the prior art.
The application provides a distributed energy storage access terminal, include: the system comprises a CPU module, an alternating current sampling module, a direct current sampling module, an input and output module and a communication module;
the CPU module, the alternating current sampling module, the direct current sampling module and the input and output module carry out information interaction through an internal bus;
the CPU module comprises a main control CPU core and an auxiliary CPU core which are used for carrying out interaction of shared data through a shared memory;
the main control CPU core is used for calculating the operation parameters of the energy storage device and carrying out corresponding logic control according to the operation control optimization strategy and algorithm of the energy storage device designed by software based on the received control instruction of the remote master station and the operation data of the energy storage access terminal, and carrying out coordination control optimization on the energy storage device; or responding to the control instruction of the remote master station to perform aggregation control on the energy storage device;
the auxiliary CPU core is used for carrying out communication management and protocol conversion on the energy storage access terminal, carrying out communication management on the outside and carrying out communication and display on an internal bus;
the alternating current sampling module is used for converting commercial power into direct current;
the direct current sampling module is used for supplying direct current when the energy storage access terminal is powered off;
the opening-in and opening-out module is used for providing opening-in signal acquisition of a tripping outlet, a control relay outlet and a hard pressing plate or opening-in signal acquisition of a switch position;
the communication module is connected with the main control CPU core and used for transmitting upgrading software to the main control CPU core so as to upgrade the main control unit.
Optionally, the system further includes a standby CPU, connected to the main control CPU core, and configured to read a heartbeat packet of the main control CPU core and jump to a new main control CPU core when the main control CPU core is abnormal.
Optionally, the system further comprises a signal conversion unit and an uploading unit, which are connected with the master control CPU core; the signal conversion unit is used for converting the alternating current amount at the common contact point into a voltage signal and transmitting the voltage signal to the uploading unit.
Optionally, the system further comprises an upload unit connected to the main control CPU core; and the uploading unit is used for converting the voltage signal into a digital quantity and uploading the digital quantity to the main control CPU core.
Optionally, the mobile terminal further comprises an input unit, configured to input and display the operating parameters of the access terminal.
Optionally, the system further comprises a state display unit, wherein the state display unit is connected with the auxiliary CPU and used for displaying the running state of the connected energy storage device.
Optionally, the operation state specifically includes operation, exception, overhaul, trip, switch-on, grid connection, and grid disconnection.
Optionally, the coordination control optimization specifically includes a peak clipping and valley filling mode, a power demand charge management mode, a primary frequency modulation mode, and a dynamic reactive power regulation mode.
Optionally, the CPU module is specifically a chip TI OMAP 138.
Optionally, the system further comprises an ethernet communication unit connected with the CPU module, and is used for performing data interactive transmission with a remote master station and a distribution network scheduling center through IEC-60870-5-104, and supports Modbus-TCP and IEC-60870-5-103 communication protocols.
According to the technical scheme, the embodiment of the application has the following advantages:
the application provides a distributed energy storage access terminal, include: the system comprises a CPU module, an alternating current sampling module, a direct current sampling module, an input and output module and a communication module; the CPU module, the alternating current sampling module, the direct current sampling module and the input and output module carry out information interaction through an internal bus; the CPU module comprises a main control CPU core and an auxiliary CPU core which are used for carrying out interaction of shared data through a shared memory; the main control CPU core is used for calculating the operation parameters of the energy storage device and carrying out corresponding logic control according to the operation control optimization strategy and algorithm of the energy storage device designed by software based on the received control instruction of the remote master station and the operation data of the energy storage access terminal, and carrying out coordination control optimization on the energy storage device; or responding to the control instruction of the remote master station to perform aggregation control on the energy storage device; the auxiliary CPU core is used for carrying out communication management and protocol conversion on the energy storage access terminal, carrying out communication management on the outside and carrying out communication and display on an internal bus; the alternating current sampling module is used for converting commercial power into direct current; the direct current sampling module is used for supplying direct current when the energy storage access terminal is powered off; the opening-in and opening-out module is used for providing opening-in signal acquisition of a tripping outlet, a control relay outlet and a hard pressing plate or opening-in signal acquisition of a switch position; the communication module is connected with the main control CPU core and used for transmitting upgrading software to the main control CPU core so as to upgrade the main control unit.
The distributed energy storage access terminal can access energy storage systems of different types and different capacities into a cloud platform, and can implement coordinated control optimization on the connected energy storage systems or respond to a control instruction of a remote master station to perform aggregation control on the energy storage systems. The control modes are diversified, and based on the multiple control modes and the acquired operation data of the energy storage system, data calculation is carried out and the current most suitable control mode is implemented so as to improve the equipment utilization rate of the energy storage system; based on an optimization control strategy and algorithm and the acquired operation control data of the energy storage system, data calculation is carried out and the current optimal control mode is implemented, so that the equipment utilization rate and the application value of the energy storage system are improved, and the technical problems of small capacity and single function of a single distributed energy storage system in the prior art are solved.
Drawings
Fig. 1 is a schematic flowchart of a connection between a distributed energy storage access terminal and an energy storage system according to an embodiment of the present disclosure;
fig. 2 is a schematic connection diagram of a distributed energy storage access terminal and a cloud platform according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a distributed energy storage access terminal according to an embodiment of the present application;
fig. 4 is a flowchart of a control mode of a distributed energy storage access terminal according to an embodiment of the present application;
reference numerals:
a master CPU core 101; an auxiliary CPU core 102; a standby CPU 103; an ethernet communication unit 104; an input unit 105; a communication module 106; a signal conversion unit 107; an upload unit 108; a status display unit 110.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The distributed energy storage access terminal provided by the embodiment of the application can access energy storage systems of different types and different capacities into a cloud platform, and can implement coordinated control optimization on the connected energy storage systems or respond to a control instruction of a remote master station to perform aggregation control on the energy storage systems. The control modes are diversified, and based on the multiple control modes and the acquired operation data of the energy storage system, data calculation is carried out and the current most suitable control mode is implemented so as to improve the equipment utilization rate of the energy storage system; based on an optimization control strategy and algorithm and the acquired operation control data of the energy storage system, data calculation is carried out and the current optimal control mode is implemented, so that the equipment utilization rate and the application value of the energy storage system are improved, and the technical problems of small capacity and single function of a single distributed energy storage system in the prior art are solved.
Referring to fig. 1 to 4, fig. 1 is a schematic flowchart illustrating a connection process between a distributed energy storage access terminal and an energy storage system according to an embodiment of the present disclosure; fig. 2 is a schematic connection diagram of a distributed energy storage access terminal and a cloud platform according to an embodiment of the present application; fig. 3 is a schematic structural diagram of a distributed energy storage access terminal according to an embodiment of the present application; fig. 4 is a flowchart of a control mode of a distributed energy storage access terminal according to an embodiment of the present application;
the embodiment of the application provides a distributed energy storage access terminal, including:
the system comprises a CPU module, an alternating current sampling module, a direct current sampling module, an input and output module and a communication module;
the CPU module, the alternating current sampling module, the direct current sampling module and the input-output module carry out information interaction through an internal bus;
the CPU module comprises a main control CPU core and an auxiliary CPU core which are used for carrying out interaction of shared data through a shared memory;
the main control CPU core is used for calculating the operation parameters of the energy storage device and carrying out corresponding logic control according to the operation control optimization strategy and algorithm of the energy storage device designed by software based on the received control instruction of the remote master station and the operation data of the energy storage access terminal, and carrying out coordination control optimization on the energy storage device; or responding to a control instruction of the remote master station to perform aggregation control on the energy storage device;
the auxiliary CPU core is used for carrying out communication management and protocol conversion on the energy storage access terminal, carrying out communication management on the outside and carrying out communication and display on an internal bus;
the alternating current sampling module is used for converting commercial power into direct current;
the direct current sampling module is used for supplying direct current when the energy storage access terminal is powered off;
the opening-in and opening-out module is used for providing opening-in signal acquisition of a tripping outlet, a control relay outlet and a hard pressing plate or opening-in signal acquisition of a switch position;
the communication module is connected with the main control CPU core and used for transmitting the upgrading software to the main control CPU core so as to upgrade the main control unit.
It should be noted that, according to fig. 2, the distributed energy storage access terminal provided in the embodiment of the present application is communicatively interconnected with the energy storage device (the energy storage system shown in fig. 1), and the remote master station (i.e., the cloud platform) through ethernet and a standardized protocol. The energy storage device is connected with a power grid through equipment such as an energy storage converter, a transformer and a switch. The interfaces of the ethernet communication module 106104 in the distributed energy storage terminal support multiple communication protocols, so that energy storage devices of different types and different capacities can be connected with the distributed energy storage terminal through the interfaces and access the cloud platform. The ethernet communication unit 104 is connected to the load circuit breaker and the distributed battery management system through a control network, and completes data interaction tasks such as fault detection, real-time data acquisition, power command issuing, and the like. The system supports IEC-60870-5-104 standard protocols, can realize millisecond-level real-time dynamic response control on the microgrid, and simultaneously avoids a large number of IO cable connections among devices. In order to improve the real-time performance of the terminal, double-CPU hierarchical control is adopted, a main control CPU core 101 completes real-time control logics such as system SOC calculation, charging and discharging required current/voltage calculation and control, distributed energy storage system power distribution, residual charging time calculation, insulation detection and the like, and an auxiliary CPU core 102 is used for data monitoring, historical data inquiry, power grid operation state monitoring and display, data uploading and downloading and the like.
The AC sampling module can convert AC mains supply AC220V into a 24V DC power supply, which is a main power supply of the energy storage access terminal. The direct current sampling module absorbs electric energy from a direct current 24V bus when the alternating current commercial power is normally supplied, and can supply power to the energy storage access terminal when the power is cut off. The opening and opening module comprises an opening and opening control unit and an opening and opening acquisition unit, the opening control unit is used for providing a tripping outlet and controlling the outlet of the relay, and the opening and opening acquisition unit is used for acquiring opening and closing signals of the hard pressing plate and the switch position. The opening-in signals of the hard pressing plate and the switch position are electric signals sent by an auxiliary contact of an external switch or an opening-out relay of the device, and the opening-in signals are used for enabling the energy storage access terminal to receive information such as the running state of the on-off state of the external switch.
The communication module 106 is specifically a USB communication unit, and can transmit a software program and a programming program to the access terminal through a USB interface, so as to upgrade the main control program. The communication module 106 is provided with a serial port submodule and a network port submodule, and is connected with the CPU module through the network port submodule and is connected with the internal bus through the serial port submodule.
Further, the system further includes a standby CPU103, connected to the main control CPU core 101, and configured to read a heartbeat message of the main control CPU core 101 and jump to a new main control CPU core 101 when the main control CPU core 101 is abnormal.
It should be noted that, in order to improve the stability of the energy storage access terminal in the embodiment of the present application, a standby CPU103 connected to the main control CPU core 101 is further provided, where the standby CPU103 CAN read a CAN heartbeat packet of the main control CPU core 101, and when it is detected that an abnormality occurs in the main control CPU core 101, the standby CPU is switched to a new main control CPU core 101, and the original main control CPU core 101 is switched to a new standby control CPU.
When the power grid is scheduled to send power demands to the micro-grid:
1. the ethernet communication unit 104 connected to the auxiliary CPU core 102 receives the power instruction value issued by the scheduling.
2. The auxiliary CPU core 102 switches the operation mode and changes the liquid crystal display data according to the instruction, and transmits the power instruction value to the main CPU core 101 through CAN communication.
3. After receiving the power instruction value, the main control CPU core 101 inputs information according to the connected ethernet communication unit 104, the access module, the signal conversion unit 107, and the like; after calculation, an output opening signal is output through the opening module and data information is output through the connected Ethernet communication unit 104; storing data and information to be recorded into an SSD of 256G; and transmits the relevant display information to the display screen.
4. If the operation is abnormal due to the abnormal master control, the standby CPU103 is switched to undertake the calculation processing function;
5. if the CPU program needs to be upgraded, the program and the programming program are transmitted through the communication module 106.
Further, the energy storage access terminal specifically further includes a signal conversion unit 107 and an upload unit 108, both of which are connected to the main control unit; the signal conversion unit 107 is used for converting the alternating current amount at the common contact point into a voltage signal and transmitting the voltage signal to the uploading unit 108; the uploading unit 108 is used for converting the voltage signal into a digital quantity and uploading the digital quantity to the main control unit.
Further, the system also comprises a signal conversion unit 107 connected with the master control CPU core 101; the signal conversion unit 107 is used for converting the alternating current amount at the common contact point into a voltage signal and transmitting the voltage signal to the uploading unit.
It should be noted that the signal conversion unit 107 can isolate the ac electric quantities near the common contact point, including the current sensor CT and the voltage sensor PT on the microgrid side and the microgrid side, by the auxiliary converter, and convert the ac electric quantities into voltage signals, which are sent to the uploading unit 108.
Further, the system also comprises an uploading unit which is connected with the master control CPU core; and the uploading unit is used for converting the voltage signal into a digital quantity and uploading the digital quantity to the main control CPU core.
It should be noted that the upload unit 108 converts an analog quantity of the received voltage signal into a digital quantity and uploads the digital quantity to the main control CPU core 101.
Further, an input unit 109 is included for inputting and displaying operating parameters of the access terminal.
It should be noted that the input unit 105 of the energy storage access terminal provided in the embodiment of the present application may be a touch display screen, and the touch display screen may perform human-computer interaction, and may perform operation data display, parameter setting, cluster merging control, grid connection control, operation history data check, alarm display, and the like of the energy storage access terminal.
Further, the state display unit 110 is connected to the auxiliary control unit for displaying the operating state of the connected energy storage device.
It should be noted that the status display unit 110, specifically, the LED operating status light, connected to the auxiliary control unit is provided with a status light in the same common operating status of all energy storage devices, and when the operating status of a certain energy storage device changes, the status light in the changed status will display.
Further, the operation state specifically includes operation, abnormity, overhaul, trip, switch-on, grid connection and grid disconnection.
It should be noted that, the status lights are provided in one-to-one correspondence to all current operating statuses of all energy storage devices, and the operating statuses respectively include operation, abnormality, maintenance, trip, switch-on, grid connection, and grid disconnection. For example, when the state of the energy storage device 1 is running, the led lamp at the running position of the state of the energy storage device 1 will display. When the state of the energy storage device 2 is abnormal, the led lamp at the abnormal position of the state of the energy storage device 2 displays correspondingly.
Further, the coordination control optimization specifically comprises a peak clipping and valley filling mode, a power demand charge management mode, a primary frequency modulation mode and a dynamic reactive power regulation mode.
It should be noted that energy flowing of the energy storage device connected to the energy storage access terminal has a bidirectional property, so that the energy storage device can be used as a power supply to output energy, and can also be used as a load to adjust power. As shown in fig. 4, after the power-on initialization and the security self-check are completed, the distributed energy storage access terminal controls each distributed energy storage device to respond to power control commands from an upper computer (in-situ mode) or a power grid dispatching center (aggregation control) on the basis of meeting the local load demand, where the power control commands include a total power command, an active command, a reactive command, and the like. The coordination control optimization, namely the local control mode, comprises peak clipping and valley filling, demand electric charge management, primary frequency modulation, dynamic reactive power regulation and the like. The aggregation control mode includes AGC automatic voltage control service and AVC automatic power generation control.
The core control algorithm of each sub-process is described in detail, and the principle of the core control algorithm lies in that a micro-grid system shows a certain load characteristic to the whole power grid by adjusting the load characteristics of an energy storage device, mainly including total power, active power, reactive power and the like, and after the total active power and the total reactive power of the energy storage device are determined, the energy storage device is subjected to power distribution by adopting an energy storage system SOC (system on chip) weighted control method based on a fuzzy control theory. In particular, fuzzy control is control based on fuzzy set theory, fuzzy language and fuzzy logic, is an application of fuzzy mathematics in a control system, and is nonlinear intelligent control. The process of the fuzzy control algorithm is as follows: the microcomputer samples and obtains the accurate value of the controlled quantity, and then compares the quantity with the given value to obtain an error signal E; generally selecting an error signal E as an input quantity of a fuzzy controller, carrying out fuzzy quantization on the accurate quantity of the E to obtain a fuzzy quantity, wherein the fuzzy quantity of the error E can be represented by a corresponding fuzzy language; thus obtaining a subset E of the fuzzy linguistic set of errors E (E is actually a fuzzy vector); and then carrying out fuzzy decision by e and a fuzzy control rule R (fuzzy relation) according to a reasoning synthesis rule to obtain a fuzzy control quantity u as follows: u ═ eR.
(1) The peak clipping and valley filling strategy makes a charging and discharging plan curve of the energy storage device according to a historical load curve of the energy storage device and a peak-valley electricity price difference of a power grid, adopts a strategy of charging in a valley and discharging in a peak value, reduces the load of the power grid in the peak value, fills the valley of the electricity price, and finally reduces the energy cost. The load shifting needs to be taken as a predicted load curve on the same day according to a load historical curve, large-range load fluctuation caused by holidays, summer work time, winter work time and the like is not considered for the moment, and the power utilization curves of the loads in a certain period are determined to have similarity. The algorithm flow is stored in the main control unit 101:
step 1, acquiring a power utilization curve n days before a load, and taking a load average value at a certain moment n days before the load as a power utilization value of the load at the moment.
And 2, taking the comprehensive load curve of the n days as a predicted load curve of the current day.
Step 3, extracting a time-of-use electricity price guide curve provided by a power grid, and dividing a peak value section I, II in the electricity price curve, wherein the peak time is 7: 00-11: 00, and the peak time is 19: 00-23: 00; the ordinary time period is 11: 00-19: 00; the low-valley period is 23: 00-7: 00.
Step 4, sorting the descending values at all times according to the electricity prices in the peak time period;
and 5, taking the minimum value of the load power P charge and the energy storage rated power P at the corresponding moment as the energy storage planned power at each moment in the arrangement of the step 4, additionally accumulating and calculating the total energy E0X η (unit MWh) or the time exceeding peak value section of the energy storage system consumed by the energy storage system from the electric energy E1 and the electric energy E2, and calculating the corresponding energy storage electricity price gains C1 and C2.
Step 6, subtracting the sum of E1 and E2 from E0 to obtain the electric quantity delta E which should be supplemented by the stored energy in ordinary time, and turning to step 7 if the delta E is regular; if Δ E is negative, proceed to step 8.
Step 7, the delta E is that the regular surface energy storage system needs to supplement power at the time of low price relative to the ordinary time of the electricity price, the ordinary time intervals are sorted according to the ascending value of the electricity price, and the energy storage system starts to supplement power with rated power from the time of low price until the power supplement electric quantity is equal to the delta E or exceeds the ordinary time intervals; the power supply cost of the section is calculated to be C3.
And 8, if the delta E is negative, indicating that the energy storage system can still discharge in the electricity price ordinary period, sequencing the ordinary periods according to the electricity price descending value, discharging the energy storage system from the high price moment according to the minimum value of the load power and the quota power until the discharge electric quantity is equal to the delta E or the period exceeding the ordinary period is over, and calculating the discharge income of the period to be C3.
And 9, sequencing the electricity prices of the valley sections from small to large, supplementing electricity by the energy storage system at rated power at each moment until the electric quantity of the energy storage system is equal to E0, and calculating the electricity supplementing cost to be C4.
And 10, calculating the difference between the sum of C1, C2 and C3 and C4 to obtain the 'peak clipping and valley filling' income of the day, wherein C3 is a signed number.
And 11, performing charge and discharge control on the energy storage system according to the charge and discharge plans formulated in the steps 1 to 9.
In particular, the load curve of the previous n days in the distributed energy storage access terminal is temporarily set as the load electricity curve of the previous 5 days, and η is temporarily 95%.
(2) Active and reactive power distribution strategy: when considering dynamic power distribution, the microgrid as a whole needs to consider not only the energy storage device but also the energy consumption of the load. In systems such as electric power market support services AGC and AVC, load changes can sometimes reduce the output of the energy storage device and sometimes increase the power output of the energy storage device due to the presence of the load, which need to be taken into account in formulating the active and reactive power allocations.
(3) Capacity electric charge management algorithm: the capacity charge management characteristics aiming at large-scale industrial and commercial users are formulated aiming at the power grid, in order to smooth the power load curve of the users to the power grid, the energy storage system absorbs electric energy when the power consumption of the users is low, and the electric energy is released when the power consumption is high, so that the power consumption peak value of the users to the power grid is reduced, and the capacity charge is low. The capacity electric charge management aims at an electric load curve, the energy storage device discharges in a load peak value section to control the maximum power demand of the load on the power grid not to exceed a set value, and the charging control is preferably performed when the power grid is low-priced in the rest time.
Two conditions required for capacity charge management are: the difference between the instantaneous maximum load power Pmax and the P cannot exceed the rated power P of the energy storage system; the initial energy E of the energy storage system in the compensation interval must be greater than or equal to the energy storage to-be-compensated electric quantity Ei, otherwise, the system power is greater than P. Firstly, evaluating the demand electric charge management according to a historical load curve, and performing power compensation in a load peak value section when the capacity management is met, so that the load of the micro-grid on the power grid as a whole does not exceed a set capacity management limit value; otherwise, the user is prompted to increase or change the capacity of the energy storage device or adjust the same-energy plan.
The specific implementation steps of the capacity electric charge management are as follows:
step 1, obtaining the comprehensive load curve of the previous 5 days, namely the maximum value of a certain moment in [ 0-24 h ] is the value of the point of the comprehensive load curve of the previous 5 days.
Step 2, judging whether the difference between the maximum value of the historical power load and the set capacity value is less than or equal to the rated input power of the energy storage system or not, and exiting if not; if so, continue with step 3.
And 3, dividing a region needing power compensation according to the load curve, and setting the discharge power of the stored energy to be the minimum value between the P charge-0.95P and the rated power of the stored energy in order to prevent the small range from exceeding the P set caused by actual load fluctuation.
And 4, integrating the Pt to calculate the electric quantity E released by the energy storage system in the interval.
And 5, performing energy absorption integral calculation of the energy storage system between the current interval and the next compensation interval, wherein the calculation requires that Pt is equal to P and the difference between P and P is multiplied by 0.95, wherein 0.05 is a safety margin. And (4) requiring Pt to be less than or equal to P, and adding the sum of the obtained energy through integration and the initial value of the integration to ensure that the electric energy cannot exceed the rated capacity E0 of the energy storage system.
And 6, judging whether E0 is greater than or equal to E1, whether E0-E1+ E1' is greater than E2, and the like, and exiting if one is not greater than the E2.
And 7, making a required electric charge management discharge plan curve of the energy storage system according to the previous 6 steps.
And 8, starting a charging plan when power compensation is not needed for 5 minutes or more continuously according to the fluctuation characteristic of the actual load of the capacity and electricity charge manager.
And 9, during charging, the charging power of the energy storage system is the minimum value of 0.95(P is set to-P charge) and P, wherein 0.05 is a safety margin.
(4) The primary frequency modulation is auxiliary frequency modulation control aiming at the quality of electric energy output by a power plant, and is beneficial to the droop characteristic between the frequency of a power grid and active power. However, the generator set has slow response speed, poor primary frequency modulation dynamic characteristics, and the energy storage device has fast response speed. Therefore, the dynamic response characteristic of primary frequency modulation can be greatly improved by combining the energy storage device, a standby generator set is usually used for completing the low-frequency part in the frequency modulation command of the power grid, and the energy storage system is used for completing the high-frequency part in the frequency modulation command. The specific control flow is as follows:
step 1, initializing the device.
And 2, reading the voltage frequency of the power grid and the state of charge (SOC) of the energy storage device.
And 3, calculating a voltage frequency difference value delta f and a state of charge difference value delta SOC.
And 4, bringing the voltage frequency difference value delta f and the state of charge difference value delta SOC into a Proportional Integral (PI) control algorithm to respectively obtain an active power instruction delta Qf related to the frequency f and a power instruction delta QSOC related to the SOC.
And 5, acquiring a high-frequency part of the delta Qf through discrete Fourier transform, and distributing a low-frequency part to a standby generator set.
And 6, the power Qref to be distributed by the energy storage system is equal to the sum of the active instruction, the delta Qf high-frequency part and k × delta QSOC at the last moment.
And 7, an active power distribution strategy of the energy storage system.
In particular, the value of k is 0.1 in the embodiment of the present application, which mainly includes maintaining the energy balance of the energy storage system by adding a control quantity related to the SOC; the SOC is set as a set SOC balance value, and 0.65 is selected temporarily in the application for preventing the energy storage device from being overcharged and overdischarged.
(5) Due to the presence of reactive power, the apparent power of the system increases, which increases the capacity of the associated electrical equipment, resulting in increased volume and cost of the electrical equipment. When the reactive power increases, the electrical equipment and the line loss increase due to the increase of the total current, thereby reducing the operation efficiency of the electrical equipment. The reactive power compensation improves the power factor of a power grid and stabilizes the voltage of the power grid by reducing the reactive power of a system, at the moment, an energy storage converter PCS in an energy storage device is a PWM rectifier without a load at a direct current side in the topology, and the reactive power compensation emphasizes the control performance of the reactive current at the power grid side different from the control requirement of a common PWM rectifier. The reactive compensation control algorithm flow in the application is as follows:
step 1, initializing the device.
And 2, reading the relation between the voltage and current of the power grid and the phase thereof.
And 3, calculating the difference between the power factor q of the power grid and the set power factor qET.
And 4, obtaining the reactive power difference delta d by a PI control algorithm.
And 5, a reactive power distribution strategy.
And 6, returning.
The distributed energy storage access terminal responds to a control instruction from a power grid dispatching center (DMS) in a micro-grid under an aggregation control mode, and outputs specified active and reactive instructions to the power grid. In the mode, the energy storage system is set to meet the energy utilization requirement of a local user firstly, and then the aggregation control from the dispatching center is responded. And when the active power instruction is positive, part of energy of the energy storage system is uploaded to a power grid, and when the active power instruction is negative, each distributed energy storage device is controlled to absorb energy.
Further, the master CPU core 101 is further configured to implement an aggregation control mode on all energy storage devices in response to an instruction of the cloud platform.
It should be noted that the distributed access terminal provided by the embodiment of the present application is also capable of responding to power control commands from a grid loudness center (aggregation control mode), including a total power command, an active command, and a reactive command. The aggregation control mode specifically includes an AGC power market assistance service and an AVC power market assistance service. The AGC power market auxiliary service specifically comprises an AGC algorithm flow: the electric power market auxiliary frequency modulation service AGC utilizes the droop characteristics of the active power and the power grid frequency of the power grid, namely the power grid frequency is reduced when the active power is high, and the power grid frequency is increased when the active power is low. Therefore, the active power command distribution of the energy storage device to the power grid is mainly aimed at this time, energy is output when the active power is positive, and energy is absorbed when the active power is negative.
The AVC electric power market auxiliary service is specifically an AVC algorithm flow: the AVC utilizes the drooping characteristics of the reactive power and the voltage amplitude of the power grid, namely the amplitude of the power grid is reduced when the reactive power is high, and the amplitude of the power grid is increased when the active power is low. Therefore, the reactive power instruction distribution of the energy storage device to the power grid is mainly aimed at the moment, when the reactive power is positive, the micro-power grid is inductive, and the current flowing into the power grid of the energy storage system lags the voltage of the power grid; when the reactive power is negative, the micro-grid is capacitive, and the current on the side of the grid leads the voltage of the grid.
Further, the Ethernet communication module 104 is used for performing data interactive transmission with the cloud platform through an IEC-60870-5-104 protocol, and simultaneously supports a Modbus-TCP or an IEC-60870-5-103 communication protocol.
It should be noted that the ethernet communication module 104 performs data interactive transmission with a cloud platform, a remote master station, a distribution network scheduling center, and the like through IEC-60870-5-104, so as to meet the standard interoperability requirement. Meanwhile, the Modbus-TCP, IEC-60870-5-103 and other communication protocols can be selectively supported, and sufficient flexibility and compatibility are provided.
Further, the CPU module is specifically a chip TI OMAP 138.
It should be noted that the CPU module is a dual-core chip, and particularly, the chip used in this application is tiomac 138, and another dual-core chip may be applied to the CPU module of this application in place of the chip.
Further, the ethernet communication unit 104 also includes a software communication unit for processing different protocols.
It should be noted that the ethernet communication unit 104 includes a plurality of ethernet interfaces and stores software communication processing programs, so that the ethernet communication unit 104 supports a plurality of communication protocols for processing functions of different protocols by the software programs.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (10)
1. A distributed energy storage access terminal, comprising: the system comprises a CPU module, an alternating current sampling module, a direct current sampling module, an input and output module and a communication module;
the CPU module, the alternating current sampling module, the direct current sampling module and the input and output module carry out information interaction through an internal bus;
the CPU module comprises a main control CPU core and an auxiliary CPU core which are used for carrying out interaction of shared data through a shared memory;
the main control CPU core is used for calculating the operation parameters of the energy storage device and carrying out corresponding logic control according to the operation control optimization strategy and algorithm of the energy storage device designed by software based on the received control instruction of the remote master station and the operation data of the energy storage access terminal, and carrying out coordination control optimization on the energy storage device; or responding to the control instruction of the remote master station to perform aggregation control on the energy storage device;
the auxiliary CPU core is used for carrying out communication management and protocol conversion on the energy storage access terminal, carrying out communication management on the outside and carrying out communication and display on an internal bus;
the alternating current sampling module is used for converting commercial power into direct current;
the direct current sampling module is used for supplying direct current when the energy storage access terminal is powered off;
the opening-in and opening-out module is used for providing opening-in signal acquisition of a tripping outlet, a control relay outlet and a hard pressing plate or opening-in signal acquisition of a switch position;
the communication module is connected with the main control CPU core and used for transmitting upgrading software to the main control CPU core so as to upgrade the main control CPU core.
2. The distributed energy storage access terminal according to claim 1, further comprising a standby CPU, connected to the main control CPU core, and configured to read a heartbeat packet of the main control CPU core and jump to a new main control CPU core when the main control CPU core is abnormal.
3. The distributed energy storage access terminal according to claim 1, further comprising a signal conversion unit connected to the main control CPU core; the signal conversion unit is used for converting the alternating current amount at the common contact point into a voltage signal and transmitting the voltage signal to the uploading unit.
4. The distributed energy storage access terminal according to claim 3, further comprising an upload unit connected to the main control CPU core; and the uploading unit is used for converting the voltage signal into a digital quantity and uploading the digital quantity to the main control CPU core.
5. The distributed energy storage access terminal of claim 1, further comprising an input unit configured to input and display an operating parameter of the access terminal.
6. The distributed energy storage access terminal according to claim 1, further comprising a status display unit, connected to the auxiliary CPU, for displaying an operation status of the connected energy storage device.
7. The distributed energy storage access terminal according to claim 6, wherein the operation status specifically includes operation, exception, maintenance, trip, switch-on, grid-connection, and off-grid.
8. The distributed energy storage access terminal according to claim 1, wherein the coordination control optimization specifically includes a peak clipping and valley filling mode, a power demand management mode, a primary frequency modulation mode, and a dynamic reactive power regulation mode.
9. The distributed energy storage access terminal according to claim 1, wherein the CPU module is specifically a chip TI OMAP 138.
10. The distributed energy storage access terminal of claim 1, further comprising an ethernet communication unit connected to the CPU module, configured to perform data interactive transmission with a remote master station and a distribution network scheduling center through IEC-60870-5-104, and support Modbus-TCP and IEC-60870-5-103 communication protocols.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110880985A (en) * | 2019-10-28 | 2020-03-13 | 广东电网有限责任公司 | Distributed energy storage access terminal |
| CN112953599A (en) * | 2021-03-29 | 2021-06-11 | 广东电网有限责任公司电力科学研究院 | Energy storage access terminal with power broadband carrier function |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110880985A (en) * | 2019-10-28 | 2020-03-13 | 广东电网有限责任公司 | Distributed energy storage access terminal |
| CN112953599A (en) * | 2021-03-29 | 2021-06-11 | 广东电网有限责任公司电力科学研究院 | Energy storage access terminal with power broadband carrier function |
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