Power transformer and photovoltaic and energy storage integrated electric energy regulation and control system

Abstract

The invention belongs to the field of power system control, and particularly discloses a power transformer, photovoltaic and energy storage integrated electric energy regulation and control system which comprises a power generation and energy storage optimization scheduling module, a load balance control module, a fault diagnosis and processing module cabinet and a communication module. The system can monitor the operation states of the power transformer, the photovoltaic power station and the energy storage device in real time, and controls the power directions of the photovoltaic inverter and the energy storage converter in real time according to the load condition of the power transformer in combination with the current power grid policy, the peak-valley time period and the electricity price policy, so as to solve the overload problem of the power transformer and improve the safety of the power transformer. And the most economical and environment-friendly electric energy distribution and utilization are realized.

Description

Technical Field

[0001] The present invention belongs to the field of power system control, and specifically relates to a power transformer, photovoltaic and energy storage integrated power control system. Background Art

[0002] Photovoltaic power generation is one of the most mature and promising renewable energy sources. With the increasing proportion of installed capacity of photovoltaic power stations, the impact of photovoltaic power generation system grid connection on the power grid has become more prominent. Common impacts include the random fluctuation of active power output when it passes through the nearby power grid and long-distance transmission channels, which will affect the reactive balance characteristics of the power grid. It has maintained a strong development momentum in recent years. During photovoltaic power generation, since solar panels are affected by light and temperature, when the external environment changes rapidly, the photovoltaic power generation power will also change rapidly, and it is impossible to ensure stable power output to the power grid. Usually, the active power of the power grid is adjusted by controlling the access and exit of photovoltaic inverters. The existing power control system cannot control the power relationship between power transformers, photovoltaics and energy storage, and cannot effectively combine relevant conditions such as power grid policies and peak and valley periods to effectively utilize electricity, resulting in reduced power generation efficiency of photovoltaic power stations and unstable grid connection. Summary of the invention

[0003] In order to address the deficiencies of the prior art, the present invention aims to provide an integrated power control system of power transformers, photovoltaics and energy storage. The system can monitor the operating status of power transformers, photovoltaic power stations and energy storage devices in real time, and control the power direction of photovoltaic inverters and energy storage converters in real time according to the load of the power transformer and in combination with the current grid policy, peak and valley time periods and electricity price policy, so as to solve the problem of power transformer overload and achieve the most economical and environmentally friendly power distribution and utilization.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: An integrated power control system of power transformer, photovoltaic and energy storage, which collects data of equipment including power transformer, converter, inverter and battery management system in real time, analyzes their working data, judges the state of power grid and load; calculates active power, reactive power and power flow, and generates control instructions for each device; also has a recording function, uploads equipment data and working status through the network, and accurately controls and manages the energy storage system; the control system includes power generation and energy storage optimization scheduling module, load balancing control module and fault diagnosis, processing module cabinet and communication module; The power generation and energy storage optimization scheduling module is used to determine the power flow direction according to the current time and the state of the energy storage system, calculate the power generation of the photovoltaic power generation system, the load demand of the power transformer and the state of the energy storage system, and configure and schedule the photovoltaic power generation and energy storage devices to improve energy utilization efficiency; The load balancing control module adjusts the operation mode of the photovoltaic power generation and energy storage system by real-time monitoring of the photovoltaic output power and the charge state of the energy storage battery group, realizes load balancing control, and controls the charge and discharge rate and depth of the energy storage battery group to avoid overcharging, overdischarging and overloading of the energy storage battery group; The fault diagnosis and processing module monitors and analyzes the operating data of photovoltaic modules, energy storage battery group BMS, energy storage converter, and photovoltaic inverter to timely detect and handle faults and ensure the safe and reliable operation of the system; The communication module is used for communication between devices and between the system and the background.

[0005] Furthermore, the power generation and energy storage optimization scheduling module adjusts the power flow according to different time periods and includes: During the daytime peak hours, the rooftop photovoltaic panels and energy storage battery packs are simultaneously converted into AC power and fed back to the grid; during the evening peak hours, the energy storage battery pack supplies power to the grid; During the daytime, the rooftop photovoltaic modules supply power to the grid and the energy storage battery pack; during the evening, if the energy storage battery is fully charged, it supplies power to the grid. During off-peak hours, the AC power on the grid is converted into DC power to charge the energy storage battery pack.

[0006] Furthermore, the equipment used for regulation by the regulation system includes an integrated power regulation cabinet, a power transformer, a rooftop photovoltaic system, a photovoltaic grid-connected inverter, and a storage battery pack; the power transformer, the rooftop photovoltaic system, the photovoltaic grid-connected inverter, and the storage battery pack are all connected to the integrated power regulation cabinet.

[0007] Preferably, the integrated power control cabinet integrates bidirectional DC / AC, HMI, communication hub, and AC / DC power distribution devices.

[0008] Furthermore, the control modes of the control system for regulating power equipment include timing mode, peak-valley arbitrage mode, voltage maintenance mode, transformer capacity expansion mode, load capacity expansion mode, power limitation mode, peak shaving mode and backup power supply mode.

[0009] Furthermore, the control system executes a timing mode: setting the energy storage system to charge or discharge in different time periods every day; Execute the peak-valley arbitrage model: discharge during peak hours and charge during valley hours; Execute voltage maintenance mode: The energy storage system outputs active power and reactive power to offset the voltage drop in the circuit and adjust the grid-connected voltage; Execute transformer expansion mode: When the load power consumption is higher than the transformer discharge percentage value, the energy storage system discharges to supplement the excess load power consumption; when the load power consumption is lower than the transformer charging percentage, the grid charges the energy storage system; Execute load expansion mode: When the load power consumption is too high, an alarm will be sent, and the battery discharge can be set to reduce the power purchased from the grid; Execute power restriction mode: set a fixed time period to limit the power purchased from the power grid; outside the limited power purchase time period, the energy storage system charging time and charging power can be set; when the load power usage exceeds the limited power purchase, the energy storage system discharges to supplement the excess power; Execute peak shaving mode: When the load power consumption is higher than the maximum control point, the energy storage system discharges to supplement and reduce the power purchased by the power grid, so that the power purchased by the power grid is maintained below the maintenance point; when the load power consumption is lower than the idle point, the power grid charges the energy storage system; due to the small capacity of the energy storage battery system, the working time of the peak shaving mode can be adjusted according to the load; Execute backup power mode: Set the energy storage system discharge SOC when the grid is out of power. When it is lower than this value, the energy storage system stops discharging and switches to standby mode. When the grid resumes power supply, the energy storage system charges to maintain the SOC range.

[0010] Furthermore, the communication module communicates between devices via CAN or RS485 communication, and the communicating devices include bidirectional AC / DC converters, DC / DC converters, electrochemical energy storage battery packs BMS, and power transformer multi-function meters; the communication module connects the control system with the background monitoring center and NTP server via Ethernet communication.

[0011] The beneficial effects of the present invention are: The power transformer, photovoltaic and energy storage integrated power control system provided by the present invention collects data of power transformers, converters, inverters, battery management systems and other equipment in real time, including parameters such as power, current, voltage, etc., analyzes their working data, and determines the power grid and load status; calculates active power, reactive power and power flow, generates control instructions for each device, and sends them to the corresponding equipment via the field bus to perform corresponding actions; the system has a recording function, and can upload equipment data and working status through the network to achieve precise control and management of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram of the energy storage system of the present invention; Figure 2 It is a human-computer interaction menu structure diagram of the system management interface of the present invention; Figure 3 This is a diagram of the electric energy regulation mode of the present invention; Figure 4 It is the system control logic diagram of the present invention; Figure 5 is a timing mode logic diagram of the present invention; Figure 6It is the logic diagram of the peak-valley arbitrage model of the present invention; Figure 7 It is a logic diagram of the transformer capacity expansion mode of the present invention; Figure 8 It is a logic diagram of the load expansion mode of the present invention; Fig. 9 It is the logic diagram of the power-limiting mode of the present invention; Fig.10 It is the peak shaving mode logic diagram of the present invention; Fig.11 This is a logic diagram of the backup power mode of the present invention. DETAILED DESCRIPTION

[0013] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of use of the present invention.

[0014] like Figure 1-11 As shown, the present invention proposes an integrated power control system of power transformer, photovoltaic and energy storage, which can monitor the operating status of power transformer, photovoltaic power station and energy storage device in real time, and control the power direction of photovoltaic inverter and energy storage converter in real time according to the load of power transformer and in combination with current grid policy, peak and valley time period and electricity price policy, so as to solve the overload problem of power transformer and realize the most economical and environmentally friendly power distribution and utilization.

[0015] The control system provided by the present invention collects data from devices including power transformers, converters, inverters, and battery management systems in real time, analyzes their working data, and determines the power grid and load status; and calculates active power, reactive power, and power flow, and generates control instructions for each device; it also has a recording function, and uploads device data and working status through the network to accurately control and manage the energy storage system.

[0016] The control system of the present invention is equipped with a real-time clock to determine the current peak and valley time period; the real-time clock can be calibrated using an NTP server; it is equipped with an Ethernet communication function and communicates with a user application system through the Modus TCP protocol; it is equipped with Modbus RTU and other communication functions and can communicate with an energy storage converter, a photovoltaic inverter, a battery BMS, and a user DCS system to control the operation of the equipment; it is equipped with an event recording function, including converter equipment actions and faults; it can set electricity price policies, peak and valley time periods, and the charge and discharge depth of energy storage devices; it has an electric energy control strategy with two modes, automatic control and manual control; the system reserves an upgrade interface; the management software can be upgraded using tools such as a U disk; it can perform maintenance reminders: regular reminders to clean and maintain photovoltaic components, energy storage converters, grid-connected inverters and other equipment; it can also perform authority management on users to avoid modifying important parameters.

[0017] Specifically, the control system of the present invention includes a power generation and energy storage optimization scheduling module, a load balancing control module, a fault diagnosis and processing module cabinet and a communication module.

[0018] The power generation and energy storage optimization scheduling module is used to determine the power flow according to the current time and the state of the energy storage system, and calculate the power generation of the photovoltaic power generation system, the load demand of the power transformer and the state of the energy storage system, and reasonably configure and schedule the photovoltaic power generation and energy storage devices to maximize the energy utilization efficiency. Adjusting the power flow according to different time periods includes: During the daytime peak hours, the rooftop photovoltaic panels and energy storage battery packs are simultaneously converted into AC power and fed back to the grid; during the evening peak hours, the energy storage battery pack supplies power to the grid; During the daytime, the rooftop photovoltaic modules supply power to the grid and the energy storage battery pack; during the evening, if the energy storage battery is fully charged, it supplies power to the grid. During off-peak hours, the AC power on the grid is converted into DC power to charge the energy storage battery pack.

[0019] The load balancing control module monitors the photovoltaic output power and the charge state of the energy storage battery group in real time, adjusts the operation mode of the photovoltaic power generation and energy storage system, realizes load balance control, and controls the charge and discharge rate and depth of the energy storage battery group to avoid overcharging, over-discharging and overloading of the energy storage battery group.

[0020] The fault diagnosis and processing module monitors and analyzes the operating data of photovoltaic modules, energy storage battery pack BMS, energy storage converter, and photovoltaic inverter to detect and handle faults in a timely manner, ensuring the safe and reliable operation of the system.

[0021] The present invention utilizes energy storage battery groups to absorb electricity from the power grid during off-peak hours and release electricity during peak hours, thereby reducing electricity costs; utilizes rooftop photovoltaic power stations to share a DC bus with energy storage battery groups; and outputs power to the power grid at maximum power when there is sunlight.

[0022] During the day, the control system controls the photovoltaic power station to output at maximum power; according to the electricity price policy, the peak electricity price period is 8 hours a day. Considering the optimal economy of the battery pack, it is configured as two charges and two discharges, that is, charging for 4 hours during the off-peak period at night and discharging during the peak period during the day; charging for 3 hours using photovoltaics and the power grid during the day, discharging during the peak period at night, and discharging during the peak period in summer.

[0023] The power control system charges the battery during the off-peak period from 23:00 to 7:00 the next day, and discharges the battery during the peak period from 10:00 to 14:00. The battery is charged by photovoltaic power and the power grid during the flat period from 14:00 to 17:00, and discharged during the peak period from 18:00 to 21:00.

[0024] There will be peak electricity price periods from July to August and from January to December every year. The local peak periods are already included in the peak periods. The above-mentioned discharge strategy includes discharge during the peak periods to maximize the use of electricity. When the policy and period change, the charging and discharging strategy should be adjusted, and the policy data should be entered into the HMI to achieve automatic matching.

[0025] The communication module of the present invention is used for communication between devices and between the system and the background. The communication module uses CAN or RS485 communication to communicate between devices, and the communicating devices include bidirectional AC / DC converters, DC / DC converters, electrochemical energy storage battery pack BMS, and power transformer multi-function meters; the communication module connects the control system with the background monitoring center and NTP server through Ethernet communication.

[0026] The equipment used by the control system to control includes an integrated power control cabinet (integrated with bidirectional DC / AC, HMI, communication hub, AC / DC distribution devices, etc.), power transformers, rooftop photovoltaics, photovoltaic grid-connected inverters, and energy storage battery packs. The power transformers, rooftop photovoltaics, photovoltaic grid-connected inverters, and energy storage battery packs are all connected to the integrated power control cabinet.

[0027] To reduce interference, the communication line is separated from the power circuit line, and shielded cables are used, which are led to the integrated cabinet and the background monitoring center through iron wire tubes. Specifically, the output cables of the rooftop photovoltaic grid-connected inverter, the cables of the electrochemical energy storage battery group, the cables of the power transformer, and other primary cables, as well as the secondary cables such as communication, are led out to the integrated power control cabinet through the bridge or cable trench; the lead-out cable of the rooftop photovoltaic grid-connected inverter is sent out together with the output of the AC port of the bidirectional energy storage converter through AC distribution in the integrated power control cabinet; the lead-out cable of the energy storage battery group enters the DC end of the bidirectional energy storage converter through DC distribution in the integrated power control cabinet; the AC port of the bidirectional energy storage converter is connected to the power frequency transformer through AC distribution; the communication cable of the multi-function meter of the power transformer, the communication cable of the photovoltaic inverter, and the BMS communication cable of the battery group are sent to the integrated power control cabinet. The integrated power control cabinet has a communication area, reserved for isolated CAN bus and 485 bus; the communication between devices is converted into 485 bus; this 485 bus is also used as a background communication loop, and the background system can access each device separately through this 485 bus.

[0028] The integrated electric energy control cabinet of the present invention realizes system management by a touch screen, and the touch screen is composed of management software, a human-machine interface, and a communication interface; its 485 interface communicates with the equipment; and its Ethernet interface is used for background communication and NTP server time synchronization.

[0029] The control modes of the control system for power equipment include timing mode, peak-valley arbitrage mode, voltage maintenance mode, transformer capacity expansion mode, load capacity expansion mode, power restriction mode, peak shaving mode and backup power supply mode.

[0030] The control system executes the timing mode: set the energy storage system to charge or discharge at different time periods every day; Execute the peak-valley arbitrage model: discharge during peak hours and charge during valley hours; Execute voltage maintenance mode: The energy storage system outputs active power and reactive power to offset the voltage drop in the circuit and adjust the grid-connected voltage; Execute transformer expansion mode: When the load power consumption is higher than the transformer discharge percentage value, the energy storage system discharges to supplement the excess load power consumption; when the load power consumption is lower than the transformer charging percentage, the grid charges the energy storage system; Execute load expansion mode: When the load power consumption is too high, an alarm will be sent, and the battery discharge can be set to reduce the power purchased from the grid; Execute power restriction mode: set a fixed time period to limit the power purchased from the power grid; outside the limited power purchase time period, the energy storage system charging time and charging power can be set; when the load power usage exceeds the limited power purchase, the energy storage system discharges to supplement the excess power; Execute peak shaving mode: When the load power consumption is higher than the maximum control point, the energy storage system discharges to supplement and reduce the power purchased by the power grid, so that the power purchased by the power grid is maintained below the maintenance point; when the load power consumption is lower than the idle point, the power grid charges the energy storage system; due to the small capacity of the energy storage battery system, the working time of the peak shaving mode can be adjusted according to the load; Execute backup power mode: Set the energy storage system discharge SOC when the grid is out of power. When it is lower than this value, the energy storage system stops discharging and switches to standby mode. When the grid resumes power supply, the energy storage system charges to maintain the SOC range.

[0031] The power transformer, photovoltaic and energy storage integrated power control system provided by the present invention can monitor the operating status of the power transformer, photovoltaic power station and energy storage device in real time, and control the power direction of the photovoltaic inverter and energy storage converter in real time according to the load condition of the power transformer and in combination with the current grid policy, peak and valley time periods and electricity price policy, so as to solve the problem of power transformer overload and realize the most economical and environmentally friendly power distribution and utilization.

[0032] Obviously, the embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to perform equivalent replacement of some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of this application, directly or indirectly used in other related technical fields, is similarly within the scope of patent protection of this application.

Claims

1. An integrated power transformer, photovoltaic and energy storage power control system, characterized in that: The control system collects data from devices including power transformers, converters, inverters, and battery management systems in real time, analyzes their working data, and determines the state of the power grid and load; calculates active power, reactive power, and power flow, and generates control instructions for each device; it also has a recording function, uploads device data and working status through the network, and accurately controls and manages the energy storage system; the control system includes power generation and energy storage optimization scheduling modules, load balancing control modules, fault diagnosis, processing module cabinets, and communication modules; The power generation and energy storage optimization scheduling module is used to determine the power flow direction according to the current time and the state of the energy storage system, calculate the power generation of the photovoltaic power generation system, the load demand of the power transformer and the state of the energy storage system, and configure and schedule the photovoltaic power generation and energy storage devices to improve energy utilization efficiency; The load balancing control module adjusts the operation mode of the photovoltaic power generation and energy storage system by real-time monitoring of the photovoltaic output power and the charge state of the energy storage battery group, realizes load balancing control, and controls the charge and discharge rate and depth of the energy storage battery group to avoid overcharging, overdischarging and overloading of the energy storage battery group; The fault diagnosis and processing module monitors and analyzes the operating data of photovoltaic modules, energy storage battery group BMS, energy storage converter, and photovoltaic inverter to timely detect and handle faults and ensure the safe and reliable operation of the system; The communication module is used for communication between devices and between the system and the background.

2. The integrated power control system of power transformer, photovoltaic and energy storage according to claim 1 is characterized in that: The power generation and energy storage optimization scheduling module adjusts the power flow according to different time periods and includes: During the daytime peak hours, the rooftop photovoltaic panels and energy storage battery packs are simultaneously converted into AC power and fed back to the grid; during the evening peak hours, the energy storage battery pack supplies power to the grid; During the daytime, the rooftop photovoltaic modules supply power to the grid and the energy storage battery pack; during the evening, if the energy storage battery is fully charged, it supplies power to the grid. During off-peak hours, the AC power on the grid is converted into DC power to charge the energy storage battery pack.

3. The integrated power control system of power transformer, photovoltaic and energy storage according to claim 1 is characterized in that: The equipment used for regulation by the regulation system includes an integrated power regulation cabinet, a power transformer, a rooftop photovoltaic system, a photovoltaic grid-connected inverter, and an energy storage battery pack. The power transformer, the rooftop photovoltaic system, the photovoltaic grid-connected inverter, and the energy storage battery pack are all connected to the integrated power regulation cabinet.

4. The integrated power control system of power transformer, photovoltaic and energy storage according to claim 3 is characterized in that: The integrated power control cabinet integrates bidirectional DC / AC, HMI, communication hub, and AC / DC power distribution devices.

5. The integrated power control system of power transformer, photovoltaic and energy storage according to claim 1 is characterized in that: The control modes of the control system for regulating power equipment include timing mode, peak-valley arbitrage mode, voltage maintenance mode, transformer capacity expansion mode, load capacity expansion mode, power limitation mode, peak shaving mode and backup power supply mode.

6. The integrated power control system of power transformer, photovoltaic and energy storage according to claim 5 is characterized in that: The control system executes a timing mode: setting the energy storage system to charge or discharge at different time periods every day; Execute the peak-valley arbitrage model: discharge during peak hours and charge during valley hours; Execute voltage maintenance mode: The energy storage system outputs active power and reactive power to offset the voltage drop in the circuit and adjust the grid-connected voltage; Execute transformer expansion mode: When the load power consumption is higher than the transformer discharge percentage value, the energy storage system discharges to supplement the excess load power consumption; when the load power consumption is lower than the transformer charging percentage, the grid charges the energy storage system; Execute load expansion mode: When the load power consumption is too high, an alarm will be sent, and the battery discharge can be set to reduce the power purchased from the grid; Execute power restriction mode: set a fixed time period to limit the power purchased from the power grid; outside the limited power purchase time period, the energy storage system charging time and charging power can be set; when the load power usage exceeds the limited power purchase, the energy storage system discharges to supplement the excess power; Execute peak shaving mode: When the load power consumption is higher than the maximum control point, the energy storage system discharges to supplement and reduce the power purchased by the power grid, so that the power purchased by the power grid is maintained below the maintenance point; when the load power consumption is lower than the idle point, the power grid charges the energy storage system; due to the small capacity of the energy storage battery system, the working time of the peak shaving mode can be adjusted according to the load; Execute backup power mode: Set the energy storage system discharge SOC when the grid is out of power. When it is lower than this value, the energy storage system stops discharging and switches to standby mode. When the grid resumes power supply, the energy storage system charges to maintain the SOC range.

7. The integrated power control system of power transformer, photovoltaic and energy storage according to claim 1 is characterized in that: The communication module communicates between devices via CAN or RS485 communication, and the communicating devices include bidirectional AC / DC converters, DC / DC converters, electrochemical energy storage battery pack BMS, and power transformer multi-function meters; the communication module connects the control system with the background monitoring center and NTP server via Ethernet communication.

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