A method and system for monitoring the status of new energy power generation

Abstract

This invention relates to the field of new energy power generation technology, and provides a method and system for monitoring the status of new energy power generation. The method includes: constructing a grid connection point voltage model; obtaining the upper and lower limits of the grid connection voltage based on the allowable range of the grid connection point voltage and instructions from the power grid dispatch center; determining whether the grid connection point voltage exceeds the limits; if the grid connection point voltage is greater than the upper limit, obtaining the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices; if the grid connection point voltage is less than the lower limit, obtaining the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, and the reactive power of several compensation devices; determining whether the expected grid connection point voltage exceeds the limits; and establishing the reactive power output mode within the predicted time period. By adopting the above method, the power generation status can be monitored in a targeted and efficient manner, and adjustments can be made to the grid connection point voltage.

Description

Technical Field

[0001] This invention relates to the field of new energy power generation technology, and in particular to a method and system for monitoring the status of new energy power generation. Background Technology

[0002] With the advancement of new power system construction, both new energy power generation technologies and the number of power plants built have seen significant development. Because new energy power generation is highly dependent on the natural environment and suffers from unstable and uncontrollable output, new energy power plants typically integrate energy storage stations and various other equipment with the generator sets, forming combined power plants.

[0003] When a renewable energy power plant is connected to the grid, it must comply with the voltage range of the grid connection point. Adjusting the grid connection point voltage is typically done by compensating for reactive power. For combined power plants with multiple equipment stations, each type of equipment within the station has reactive power regulation capabilities.

[0004] Combined power plants should not only maintain a standard grid connection voltage, but also be subject to temporary adjustments to the grid connection voltage to a specified value during grid system dispatching. In these combined renewable energy power plants, the power output of the generator units is also affected by complex natural factors such as weather and sunlight. Furthermore, areas rich in renewable energy resources are often remote, located at the end of the grid, or in areas with underdeveloped grid infrastructure, leading to significant fluctuations in grid-connected power generation. For multi-unit combined renewable energy power plants, regulating the grid connection voltage is particularly challenging. Existing technologies lack targeted monitoring of key data affecting continuous grid connection voltage regulation, resulting in insufficient control over reactive power output distribution within the plant and low efficiency in data collection and analysis. Consequently, control effectiveness is poor under conditions of weak grid infrastructure, dispatching changes, and variations in natural factors. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for monitoring the status of new energy power generation. This invention constructs a grid connection point voltage model, monitors key parameters within the combined new energy power plant, and combines this with ultra-short-term power forecasting to achieve targeted and efficient monitoring of the power generation status within the plant. This allows for efficient control of various equipment within the plant based on the allowable range of the grid connection point voltage and dispatch instructions. The present invention aims to solve the technical problems in existing technologies, such as the difficulty in regulating the grid connection point voltage and the lack of targeted monitoring of key data affecting the continuous regulation of the grid connection point voltage, leading to insufficient control over the output distribution of reactive power within the plant.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A method for monitoring the status of new energy power generation includes the following steps:

[0008] Obtain the equivalent power source voltage vector, equivalent grid resistance, equivalent grid inductance, and grid-connected active power of the new energy combined power station; construct the grid connection point voltage model of the new energy combined power station, which includes generator sets, energy storage devices, several compensation devices, and induction filter transformers.

[0009] Obtain the ultra-short-term predicted power, the prediction period corresponding to the ultra-short-term predicted power, the allowable range of grid connection point voltage, and the instructions from the power grid dispatch center. Based on the allowable range of grid connection point voltage and the instructions from the power grid dispatch center, obtain the upper limit and lower limit of grid connection voltage.

[0010] Collect the grid connection point voltage of the new energy combined power station, and determine whether the grid connection point voltage exceeds the limit based on the grid connection point voltage, the upper limit of the grid connection voltage, and the lower limit of the grid connection voltage;

[0011] If the grid connection point voltage exceeds the limit and the grid connection point voltage is greater than the upper limit of the grid connection voltage, then the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices are obtained. Based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, the first maximum voltage difference is calculated, so as to perform reactive power compensation adjustment according to the first maximum voltage difference and the ultra-short-term predicted power.

[0012] If the grid connection point voltage exceeds the limit and the grid connection point voltage is less than the lower limit of the grid connection voltage, then the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, and the reactive power of several compensation devices are obtained. Based on the grid connection point voltage, the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, the second maximum voltage difference is calculated, so as to perform reactive power compensation adjustment according to the second maximum voltage difference and the ultra-short-term predicted power.

[0013] If the grid connection point voltage does not exceed the limit, then based on the grid-connected active power, the ultra-short-term predicted power and the grid connection point voltage model, the expected grid connection point voltage is calculated, and based on the expected grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage, it is determined whether the expected grid connection point voltage exceeds the limit.

[0014] If the expected grid connection point voltage exceeds the limit, the reactive power output of the generator set and the energy storage device at the current moment is obtained to determine the reactive power output mode of the generator set and the energy storage device during the predicted period.

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: By constructing the grid connection point voltage model, the minimum key parameters affecting the grid connection point voltage can be obtained, improving the targeting of new energy power generation status monitoring. The equipment for regulating reactive power within the new energy combined power station is divided, which is beneficial for efficiently changing the reactive power output mode of each device based on status monitoring, and orderly adjusting the reactive power distribution to effectively change the grid connection point voltage to meet grid connection standards and dispatch center instructions. Based on the current grid connection point voltage, it is compared with the expected grid connection standard, and cases exceeding the grid connection voltage limit are analyzed and classified, with lightweight monitoring to avoid collecting a large amount of redundant and irrelevant data, resulting in low monitoring efficiency and reduced data processing speed. Monitoring the ultra-short-term predicted power, even if the current grid connection point voltage meets the grid connection standard, also combines reactive power data monitoring within the station to plan the reactive power output mode in advance for the predicted period, adapting to complex natural factors.

[0016] Furthermore, the formula for the grid connection point voltage model is as follows:

[0017]

[0018] in, Represents the grid connection point voltage model. Indicates grid-connected reactive power. This indicates the grid-connected active power of the new energy combined power station. Represents the equivalent resistance of the power grid. This represents the equivalent inductance of the power grid.

[0019] Furthermore, the step of obtaining the upper limit and lower limit of the grid connection voltage based on the allowable voltage range of the grid connection point and the instructions from the power grid dispatch center includes:

[0020] Determine whether to perform specified voltage control based on the instructions from the power grid dispatch center;

[0021] If a specified voltage control is to be performed, the specified voltage is determined according to the instructions of the power grid dispatch center, and the specified voltage is selected as the upper limit and lower limit of the grid connection voltage.

[0022] If no specific voltage control is performed, the maximum value of the allowable range of the grid connection point voltage is established as the upper limit of the grid connection voltage, and the minimum value of the allowable range of the grid connection point voltage is established as the lower limit of the grid connection voltage.

[0023] Furthermore, the step of calculating the maximum difference in the first voltage based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model includes:

[0024] The first maximum reactive power is obtained based on the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices.

[0025] Based on the first maximum reactive power and the grid connection point voltage model, the first maximum grid connection voltage is calculated, and the difference between the first maximum grid connection voltage and the grid connection point voltage is the first maximum voltage difference.

[0026] Furthermore, the step of adjusting reactive power compensation based on the maximum difference in the first voltage and the ultra-short-term predicted power includes:

[0027] Based on the grid connection point voltage and the upper limit of the grid connection voltage, calculate the actual difference of the first voltage, and compare the actual difference of the first voltage with the maximum difference of the first voltage;

[0028] If the actual difference of the first voltage is greater than the maximum difference of the first voltage, then control the inductive filter transformer to change the reactive power flow distribution;

[0029] If the actual difference of the first voltage is less than the maximum difference of the first voltage, then the active power of the generator set is judged to have a downward trend based on the ultra-short-term predicted power.

[0030] If the active power of the generator set does not show a decreasing trend, then control several of the compensation devices to stop the reactive power output;

[0031] If the active power of the generator set shows a decreasing trend, then the energy storage device, the generator set, and several compensation devices are controlled in sequence to output reactive power.

[0032] Furthermore, the step of adjusting reactive power compensation based on the maximum difference in the second voltage and the ultra-short-term predicted power includes:

[0033] Based on the grid connection point voltage and the lower limit of the grid connection voltage, calculate the actual difference of the second voltage, and compare the actual difference of the second voltage with the maximum difference of the second voltage;

[0034] If the actual difference of the second voltage is greater than the maximum difference of the second voltage, then the inductive filter transformer is controlled to change the reactive power flow distribution.

[0035] If the actual difference of the second voltage is less than the maximum difference of the second voltage, then the active power of the generator set is judged to have an upward trend based on the ultra-short-term predicted power.

[0036] If the active power of the generator set shows an upward trend, then control several of the compensation devices to output reactive power, and control the generator set to stop outputting reactive power.

[0037] If the active power of the generator set does not show an upward trend, then the energy storage device, the generator set, and several compensation devices are sequentially controlled to output reactive power.

[0038] Furthermore, the step of calculating the expected grid connection point voltage based on the grid-connected active power, the ultra-short-term predicted power, and the grid connection point voltage model includes:

[0039] Based on the grid-connected active power and the ultra-short-term predicted power, calculate the expected grid-connected active power;

[0040] Based on the expected grid-connected active power and the grid connection point voltage model, the expected grid connection point voltage is calculated.

[0041] Furthermore, the step of determining the reactive power output mode of the generator set and the energy storage device during the predicted time period includes:

[0042] If the reactive power output is such that both the generator set and the energy storage device output capacitive reactive power, then the capacitive reactive power output by the energy storage device and the generator set is reduced sequentially until the energy storage device and the generator set stop outputting reactive power, and then the inductive reactive power of the generator set and the energy storage device is increased sequentially.

[0043] If the reactive power output is such that both the generator set and the energy storage device output inductive reactive power, then the inductive reactive power output by the energy storage device and the generator set is reduced sequentially until the energy storage device and the generator set stop outputting reactive power, and then the capacitive reactive power of the generator set and the energy storage device is increased sequentially.

[0044] A new energy power generation status monitoring system, employing the new energy power generation status monitoring method described in the above technical solution, the system comprising:

[0045] The module is used to obtain the equivalent power source voltage vector of the power grid, the equivalent resistance of the power grid, the equivalent inductance of the power grid, and the grid-connected active power of the new energy combined power station, and to construct the grid connection point voltage model of the new energy combined power station, which includes generator sets, energy storage devices, several compensation devices, and induction filter transformers.

[0046] The limiting module is used to obtain the ultra-short-term predicted power, the prediction period corresponding to the ultra-short-term predicted power, the allowable range of grid connection point voltage, and the instructions from the power grid dispatch center. Based on the allowable range of grid connection point voltage and the instructions from the power grid dispatch center, the upper limit of grid connection voltage and the lower limit of grid connection voltage are obtained.

[0047] The judgment module is used to collect the grid connection point voltage of the new energy combined power station, and determine whether the grid connection point voltage exceeds the limit based on the grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage;

[0048] The first over-limit module is used to, if the grid connection point voltage exceeds the limit and the grid connection point voltage is greater than the upper limit of the grid connection voltage, obtain the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices, and calculate the first maximum voltage difference based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, so as to perform reactive power compensation adjustment according to the first maximum voltage difference and the ultra-short-term predicted power;

[0049] The second over-limit module is used to obtain the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, and the reactive power of several compensation devices if the grid connection point voltage exceeds the limit and the grid connection point voltage is less than the lower limit of the grid connection voltage. Based on the grid connection point voltage, the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, the second voltage maximum difference is calculated so as to perform reactive power compensation adjustment according to the second voltage maximum difference and the ultra-short-term predicted power.

[0050] The prediction module is used to calculate the expected grid connection point voltage based on the grid-connected active power, the ultra-short-term predicted power and the grid connection point voltage model if the grid connection point voltage does not exceed the limit, and to determine whether the expected grid connection point voltage exceeds the limit based on the expected grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage.

[0051] The module is configured to, if the expected grid connection point voltage exceeds the limit, obtain the reactive power output of the generator set and the energy storage device at the current moment, so as to determine the reactive power output mode of the generator set and the energy storage device during the predicted period. Attached Figure Description

[0052] Figure 1 This is a flowchart of the new energy status monitoring method in the first embodiment of the present invention;

[0053] Figure 2This is a structural block diagram of the new energy status monitoring system in the second embodiment of the present invention.

[0054] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0055] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0056] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0058] Please see Figure 1 A method for monitoring the status of new energy power generation according to the first embodiment of the present invention includes the following steps:

[0059] Step S10: Obtain the grid equivalent power source voltage vector, grid equivalent resistance, grid equivalent inductance and grid-connected active power of the new energy combined power station, and construct the grid connection point voltage model of the new energy combined power station. The new energy combined power station includes generator sets, energy storage devices, several compensation devices and induction filter transformers.

[0060] Preferably, the output of new energy power generation is unstable and uncontrollable. Taking wind power as an example, wind resources are difficult to predict accurately, exhibiting randomness and intermittency. Moreover, wind resources in different regions have different characteristics, and traditional wind power stations have a high wind curtailment rate. Furthermore, the construction sites of new energy power stations are usually located in relatively remote areas, often at the end of the power grid system, with weak grid infrastructure and low grid load. Under the fluctuation of new energy power generation, the voltage fluctuation at the grid connection point is very strong. Therefore, constructing a multi-equipment combined power station, by configuring energy storage facilities and transformer facilities, namely the energy storage device, several compensation devices, and the induction filter transformer, forms a peak shaving and valley filling effect. At the same time, multiple devices have reactive power regulation functions, and multi-level composite regulation of multiple devices is beneficial to make the grid connection point voltage of the new energy combined power station stable and meet the grid connection requirements.

[0061] The formula for the grid connection point voltage model is:

[0062]

[0063] in, Represents the grid connection point voltage model. Indicates grid-connected reactive power. This indicates the grid-connected active power of the new energy combined power station. Represents the equivalent resistance of the power grid. This represents the equivalent inductance of the power grid.

[0064] Step S20: Obtain the ultra-short-term predicted power, the prediction period corresponding to the ultra-short-term predicted power, the allowable range of grid connection point voltage, and the grid dispatch center instruction; based on the allowable range of grid connection point voltage and the grid dispatch center instruction, obtain the upper limit of grid connection voltage and the lower limit of grid connection voltage.

[0065] Preferably, although the output of new energy power generation is difficult to form a long-term pattern, the existing new energy power plants all have a certain ultra-short-term prediction capability. For example, for intermittent wind power, ultra-short-term wind power prediction can be completed by combining historical data and weather. The prediction period in this embodiment is 2 hours.

[0066] Step S20 includes:

[0067] S210: Determine whether to perform specified voltage control based on the instructions from the power grid dispatch center;

[0068] S220: If specified voltage control is to be performed, the specified voltage is determined according to the instructions of the power grid dispatch center, and the specified voltage is selected as the upper limit of grid connection voltage and the lower limit of grid connection voltage.

[0069] S230: If no specified voltage control is performed, the maximum value of the allowable range of the grid connection point voltage is established as the upper limit of the grid connection voltage, and the minimum value of the allowable range of the grid connection point voltage is established as the lower limit of the grid connection voltage.

[0070] In steps S210~S230, when a specified voltage control is performed, the grid connection point voltage is no longer controlled within a specific range. Instead, the grid connection point voltage is adjusted to be equal to the specified voltage. That is, at this time, the upper limit of the grid connection voltage, the lower limit of the grid connection voltage, and the specified voltage are all equal. It can be understood that in addition to meeting the fixed grid connection voltage standard, the temporary designation by the power grid dispatch center is also very important. The new energy power generation status monitoring method adjusts the upper limit of the grid connection voltage and the lower limit of the grid connection voltage in response to the dispatch center's instructions, which is beneficial to improving the power plant's ability to handle temporary dispatch.

[0071] Step S30: Collect the grid connection point voltage of the new energy combined power station, and determine whether the grid connection point voltage exceeds the limit based on the grid connection point voltage, the upper limit of the grid connection voltage, and the lower limit of the grid connection voltage;

[0072] By comparing the values ​​of the grid connection point voltage, the upper limit of the grid connection voltage, and the lower limit of the grid connection voltage, it can be determined whether the grid connection point voltage exceeds the limit, and specifically, which limit it exceeds.

[0073] Step S40: If the grid connection point voltage exceeds the limit and the grid connection point voltage is greater than the upper limit of the grid connection voltage, then obtain the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices. Based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, calculate the first maximum voltage difference, and adjust the reactive power compensation according to the first maximum voltage difference and the ultra-short-term predicted power.

[0074] Understandably, by specifically analyzing the over-limit situation of the grid connection point voltage, current data is collected in a targeted manner. Among the several compensation devices, there are compensation devices in operation and those not in operation. The reactive power of the compensation devices is obtained. Based on the maximum difference of the first voltage, it is determined whether the current reactive power handling scheme and equipment operation scheme can handle the difference between the grid connection point voltage and the target grid connection point voltage value. Furthermore, combined with the ultra-short-term predicted power, the reactive power adjustment trend of the generator set and the energy storage device is further analyzed.

[0075] Step S40 includes:

[0076] S410: Based on the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices, obtain the first maximum reactive power;

[0077] S420: Based on the first maximum reactive power and the grid connection point voltage model, calculate the first maximum grid connection voltage. The difference between the first maximum grid connection voltage and the grid connection point voltage is the first maximum voltage difference.

[0078] Preferably, in steps S410~S420, the first maximum reactive power is substituted into the grid connection point voltage model formula to calculate the first maximum grid connection voltage.

[0079] S430: Based on the grid connection point voltage and the grid connection voltage upper limit, calculate the actual difference of the first voltage, and compare the actual difference of the first voltage with the maximum difference of the first voltage;

[0080] S440: If the actual difference of the first voltage is greater than the maximum difference of the first voltage, then control the inductive filter transformer to change the reactive power flow distribution.

[0081] S450: If the actual difference of the first voltage is less than the maximum difference of the first voltage, then determine whether the active power of the generator set has a downward trend based on the ultra-short-term predicted power.

[0082] S460: If the active power of the generator set does not show a decreasing trend, then control several of the compensation devices to stop the reactive power output;

[0083] S470: If the active power of the generator set is decreasing, then the energy storage device, the generator set and several compensation devices are controlled in sequence to output reactive power.

[0084] Preferably, in steps S430~S470, if the actual difference of the first voltage is greater than the maximum difference of the first voltage, it indicates that the current reactive power flow distribution cannot meet the grid connection voltage requirements. The induction filter transformer is switched on to change the reactive power flow distribution. If the active power of the generator set does not show a significant downward trend, the compensation device currently in operation can be switched off first. Specifically, multiple compensation devices are switched off sequentially. The remaining reactive power deficit is covered by the energy storage station, the generator set, and the compensation devices that have not yet switched off. When the reactive power deficit is still not met after the previous reactive power compensation device has processed it, the next device will output power. When the compensation device does not meet the condition for priority switch-off, that is, the active power of the generator set shows a significant downward trend, the operation status of the compensation device is maintained, and reactive power compensation is preferentially carried out through the energy storage device. The reactive power compensation method of the generator set and the energy storage device includes gradually converting inductive reactive power into capacitive reactive power.

[0085] Step S50: If the grid connection point voltage exceeds the limit and the grid connection point voltage is less than the lower limit of the grid connection voltage, then obtain the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, and the reactive power of several compensation devices. Based on the grid connection point voltage, the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, calculate the second maximum voltage difference, and adjust the reactive power compensation according to the second maximum voltage difference and the ultra-short-term predicted power.

[0086] Understandably, in conjunction with step S40, different data monitoring methods are planned for the two cases of grid connection point voltage exceeding the limit, and different monitoring data are collected in a targeted manner to prevent the collection of too much irrelevant and redundant data from reducing monitoring and control efficiency.

[0087] Step S50 includes:

[0088] S510: Based on the grid connection point voltage and the lower limit of the grid connection voltage, calculate the actual difference of the second voltage, and compare the actual difference of the second voltage with the maximum difference of the second voltage;

[0089] S520: If the actual difference of the second voltage is greater than the maximum difference of the second voltage, then control the inductive filter transformer to change the reactive power flow distribution;

[0090] S530: If the actual difference of the second voltage is less than the maximum difference of the second voltage, then determine whether the active power of the generator set has an upward trend based on the ultra-short-term predicted power.

[0091] S540: If the active power of the generator set shows an upward trend, then control several of the compensation devices to output reactive power, and control the generator set to stop outputting reactive power.

[0092] S550: If the active power of the generator set does not show an upward trend, then the energy storage device, the generator set, and several compensation devices are sequentially controlled to output reactive power.

[0093] Preferably, the calculation method of the second maximum voltage difference is the same as that of the first maximum voltage difference. If the active power of the generator set is on an upward trend, the non-operational compensation devices among the compensation devices are specifically controlled to perform reactive power compensation. Furthermore, it is necessary to determine whether the full output of the reactive power margin of the generator set at this time will affect the active power output. If it will, then the multiple generators in the generator set are prohibited from outputting power according to the reactive power margin. The same applies to the energy storage device.

[0094] Step S60: If the grid connection point voltage does not exceed the limit, calculate the expected grid connection point voltage based on the grid-connected active power, the ultra-short-term predicted power and the grid connection point voltage model, and determine whether the expected grid connection point voltage exceeds the limit based on the expected grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage.

[0095] Understandably, even if the grid connection point voltage at the current moment meets the grid connection standard, the ultra-short-term predicted power is still monitored, and the reactive power output mode during the predicted period is planned in advance to adapt to complex natural factors. Furthermore, it can better adapt to future changes in power grid dispatch.

[0096] Step S60 includes:

[0097] S610: Calculate the expected grid-connected active power based on the grid-connected active power and the ultra-short-term predicted power;

[0098] S620: Calculate the desired grid-connected point voltage based on the desired grid-connected active power and the grid-connected point voltage model.

[0099] Preferably, the desired grid-connected active power is substituted into the formula of the grid connection point voltage model, specifically into the position of the grid-connected active power.

[0100] Step S70: If the expected grid connection point voltage exceeds the limit, obtain the reactive power output of the generator set and the energy storage device at the current moment to determine the reactive power output mode of the generator set and the energy storage device during the predicted period.

[0101] Preferably, by monitoring the current data within the station and combining it with ultra-short-term forecasting technology, a power output strategy for future periods is planned.

[0102] Step S70 includes:

[0103] S710: If the reactive power output situation is that both the generator set and the energy storage device output capacitive reactive power, then the capacitive reactive power output by the energy storage device and the generator set is reduced sequentially until the energy storage device and the generator set stop outputting reactive power, and then the inductive reactive power of the generator set and the energy storage device is increased sequentially.

[0104] S720: If the reactive power output is such that both the generator set and the energy storage device output inductive reactive power, then the inductive reactive power output by the energy storage device and the generator set is reduced sequentially until the energy storage device and the generator set stop outputting reactive power, and then the capacitive reactive power of the generator set and the energy storage device is increased sequentially.

[0105] Preferably, when neither the energy storage device nor the generator set outputs reactive power, it is determined whether the range of changeable grid voltage can meet the grid connection point voltage deficit for the next time period. The grid connection point voltage deficit for the next time period is related to the ultra-short-term predicted power and grid dispatch. If it cannot meet the requirements, the inductive reactive power or capacitive reactive power of the generator set and the energy storage device is increased sequentially. The inductive-capacitive conversion process is specifically based on the currently monitored changes in reactive power within the station.

[0106] Please see Figure 2 The second embodiment of the present invention provides a new energy power generation status monitoring system, which applies the new energy power generation status monitoring method described in the first embodiment above. The system includes:

[0107] Module 10 is used to obtain the grid equivalent power source voltage vector, grid equivalent resistance, grid equivalent inductance and grid-connected active power of the new energy combined power station, and to construct the grid connection point voltage model of the new energy combined power station. The new energy combined power station includes generator set, energy storage device, several compensation devices and induction filter transformer.

[0108] The formula for the grid connection point voltage model is:

[0109]

[0110] in, Represents the grid connection point voltage model. Indicates grid-connected reactive power. This indicates the grid-connected active power of the new energy combined power station. Represents the equivalent resistance of the power grid. This represents the equivalent inductance of the power grid.

[0111] The limiting module 20 is used to obtain the ultra-short-term predicted power, the prediction period corresponding to the ultra-short-term predicted power, the allowable range of grid connection point voltage and the instructions of the power grid dispatch center, and to obtain the upper limit of grid connection voltage and the lower limit of grid connection voltage based on the allowable range of grid connection point voltage and the instructions of the power grid dispatch center.

[0112] The limiting module 20 includes:

[0113] The first unit is used to determine whether to perform specified voltage control based on the instructions from the power grid dispatch center.

[0114] The second unit is used to determine the specified voltage according to the instructions of the power grid dispatch center if specified voltage control is to be performed, and to select the specified voltage as the upper limit and lower limit of the grid connection voltage.

[0115] The third unit is used to establish the maximum value of the allowable range of the grid connection point voltage as the upper limit of the grid connection voltage and the minimum value of the allowable range of the grid connection point voltage as the lower limit of the grid connection voltage if no specified voltage control is performed.

[0116] The judgment module 30 is used to collect the grid connection point voltage of the new energy combined power station, and determine whether the grid connection point voltage exceeds the limit based on the grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage;

[0117] The first over-limit module 40 is used to, if the grid connection point voltage exceeds the limit and the grid connection point voltage is greater than the upper limit of the grid connection voltage, obtain the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices, and calculate the first maximum voltage difference based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, so as to perform reactive power compensation adjustment according to the first maximum voltage difference and the ultra-short-term predicted power.

[0118] The first over-limit module 40 includes:

[0119] The fourth unit is used to obtain the first maximum reactive power based on the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices.

[0120] The fifth unit is used to calculate the first maximum grid-connected voltage based on the first maximum reactive power and the grid connection point voltage model. The difference between the first maximum grid-connected voltage and the grid connection point voltage is the first maximum voltage difference.

[0121] The sixth unit is used to calculate the actual difference of the first voltage based on the grid connection point voltage and the upper limit of the grid connection voltage, and compare the actual difference of the first voltage with the maximum difference of the first voltage.

[0122] The seventh unit is used to control the inductive filter transformer to change the reactive power flow distribution if the actual difference of the first voltage is greater than the maximum difference of the first voltage.

[0123] The eighth unit is used to determine whether the active power of the generator set is declining based on the ultra-short-term predicted power if the actual difference of the first voltage is less than the maximum difference of the first voltage.

[0124] The ninth unit is used to control several compensation devices to stop reactive power output if the active power of the generator set does not show a decreasing trend.

[0125] The tenth unit is used to sequentially control the energy storage device, the generator set, and several compensation devices to output reactive power if the active power of the generator set shows a decreasing trend.

[0126] The second over-limit module 50 is used to, if the grid connection point voltage exceeds the limit and the grid connection point voltage is less than the lower limit of the grid connection voltage, obtain the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, and the reactive power of several compensation devices, and calculate the second maximum voltage difference based on the grid connection point voltage, the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, so as to perform reactive power compensation adjustment according to the second maximum voltage difference and the ultra-short-term predicted power;

[0127] The second over-limit module 50 includes:

[0128] The eleventh unit is used to calculate the actual difference of the second voltage based on the grid connection point voltage and the lower limit of the grid connection voltage, and compare the actual difference of the second voltage with the maximum difference of the second voltage.

[0129] The twelfth unit is used to control the inductive filter transformer to change the reactive power flow distribution if the actual difference of the second voltage is greater than the maximum difference of the second voltage.

[0130] The thirteenth unit is used to determine whether the active power of the generator set has an upward trend if the actual difference of the second voltage is less than the maximum difference of the second voltage, based on the ultra-short-term predicted power.

[0131] The fourteenth unit is used to control several of the compensation devices to output reactive power and control the generator set to stop outputting reactive power if the active power of the generator set shows an upward trend.

[0132] The fifteenth unit is used to sequentially control the energy storage device, the generator set, and several compensation devices to output reactive power if the active power of the generator set does not show an upward trend.

[0133] The prediction module 60 is used to calculate the expected grid connection point voltage based on the grid-connected active power, the ultra-short-term predicted power and the grid connection point voltage model if the grid connection point voltage does not exceed the limit, and to determine whether the expected grid connection point voltage exceeds the limit based on the expected grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage.

[0134] The prediction module 60 includes:

[0135] The sixteenth unit is used to calculate the expected grid-connected active power based on the grid-connected active power and the ultra-short-term predicted power.

[0136] The seventeenth unit is used to calculate the desired grid connection point voltage based on the desired grid-connected active power and the grid connection point voltage model.

[0137] The module 70 is configured to obtain the reactive power output of the generator set and the energy storage device at the current moment if the expected grid connection point voltage exceeds the limit, so as to determine the reactive power output mode of the generator set and the energy storage device during the predicted period.

[0138] The establishing module 70 includes:

[0139] The eighteenth unit is used to, if the reactive power output situation is that both the generator set and the energy storage device output capacitive reactive power, then sequentially reduce the capacitive reactive power output by the energy storage device and the generator set until the energy storage device and the generator set stop outputting reactive power, and then sequentially increase the inductive reactive power of the generator set and the energy storage device.

[0140] The nineteenth unit is used to, if the reactive power output situation is that both the generator set and the energy storage device output inductive reactive power, sequentially reduce the inductive reactive power output by the energy storage device and the generator set until the energy storage device and the generator set stop outputting reactive power, and then sequentially increase the capacitive reactive power of the generator set and the energy storage device.

[0141] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0142] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for monitoring the status of new energy power generation, characterized in that, Includes the following steps: Obtain the equivalent power source voltage vector, equivalent grid resistance, equivalent grid inductance, and grid-connected active power of the new energy combined power station; construct the grid connection point voltage model of the new energy combined power station, which includes generator sets, energy storage devices, several compensation devices, and induction filter transformers. Obtain the ultra-short-term predicted power, the prediction period corresponding to the ultra-short-term predicted power, the allowable range of grid connection point voltage, and the instructions from the power grid dispatch center. Based on the allowable range of grid connection point voltage and the instructions from the power grid dispatch center, obtain the upper limit and lower limit of grid connection voltage. Collect the grid connection point voltage of the new energy combined power station, and determine whether the grid connection point voltage exceeds the limit based on the grid connection point voltage, the upper limit of the grid connection voltage, and the lower limit of the grid connection voltage; If the grid connection point voltage exceeds the limit and the grid connection point voltage is greater than the upper limit of the grid connection voltage, then the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices are obtained. Based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, the first maximum voltage difference is calculated, so as to perform reactive power compensation adjustment according to the first maximum voltage difference and the ultra-short-term predicted power. If the grid connection point voltage exceeds the limit and the grid connection point voltage is less than the lower limit of the grid connection voltage, then the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, and the reactive power of several compensation devices are obtained. Based on the grid connection point voltage, the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, the second maximum voltage difference is calculated, so as to perform reactive power compensation adjustment according to the second maximum voltage difference and the ultra-short-term predicted power. If the grid connection point voltage does not exceed the limit, then based on the grid-connected active power, the ultra-short-term predicted power and the grid connection point voltage model, the expected grid connection point voltage is calculated, and based on the expected grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage, it is determined whether the expected grid connection point voltage exceeds the limit. If the expected grid connection point voltage exceeds the limit, the reactive power output of the generator set and the energy storage device at the current moment is obtained to determine the reactive power output mode of the generator set and the energy storage device during the predicted period.

2. The method for monitoring the status of new energy power generation according to claim 1, characterized in that, The steps of obtaining the upper limit and lower limit of the grid connection voltage based on the allowable voltage range of the grid connection point and the instructions from the power grid dispatch center include: Determine whether to perform specified voltage control based on the instructions from the power grid dispatch center; If a specified voltage control is to be performed, the specified voltage is determined according to the instructions of the power grid dispatch center, and the specified voltage is selected as the upper limit and lower limit of the grid connection voltage. If no specific voltage control is performed, the maximum value of the allowable range of the grid connection point voltage is established as the upper limit of the grid connection voltage, and the minimum value of the allowable range of the grid connection point voltage is established as the lower limit of the grid connection voltage.

3. The method for monitoring the status of new energy power generation according to claim 1, characterized in that, The step of calculating the maximum difference in the first voltage based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model includes: The first maximum reactive power is obtained based on the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices. Based on the first maximum reactive power and the grid connection point voltage model, the first maximum grid connection voltage is calculated, and the difference between the first maximum grid connection voltage and the grid connection point voltage is the first maximum voltage difference.

4. The method for monitoring the status of new energy power generation according to claim 1, characterized in that, The step of adjusting reactive power compensation based on the first voltage maximum difference and the ultra-short-term predicted power includes: Based on the grid connection point voltage and the upper limit of the grid connection voltage, calculate the actual difference of the first voltage, and compare the actual difference of the first voltage with the maximum difference of the first voltage; If the actual difference of the first voltage is greater than the maximum difference of the first voltage, then control the inductive filter transformer to change the reactive power flow distribution; If the actual difference of the first voltage is less than the maximum difference of the first voltage, then the active power of the generator set is judged to have a downward trend based on the ultra-short-term predicted power. If the active power of the generator set does not show a decreasing trend, then control several of the compensation devices to stop the reactive power output; If the active power of the generator set shows a decreasing trend, then the energy storage device, the generator set, and several compensation devices are sequentially controlled to output reactive power.

5. The method for monitoring the status of new energy power generation according to claim 1, characterized in that, The step of adjusting reactive power compensation based on the maximum difference of the second voltage and the ultra-short-term predicted power includes: Based on the grid connection point voltage and the lower limit of the grid connection voltage, calculate the actual difference of the second voltage, and compare the actual difference of the second voltage with the maximum difference of the second voltage; If the actual difference of the second voltage is greater than the maximum difference of the second voltage, then the inductive filter transformer is controlled to change the reactive power flow distribution. If the actual difference of the second voltage is less than the maximum difference of the second voltage, then the active power of the generator set is judged to have an upward trend based on the ultra-short-term predicted power. If the active power of the generator set shows an upward trend, then control several of the compensation devices to output reactive power, and control the generator set to stop outputting reactive power. If the active power of the generator set does not show an upward trend, then the energy storage device, the generator set, and several compensation devices are sequentially controlled to output reactive power.

6. The method for monitoring the status of new energy power generation according to claim 1, characterized in that, The step of calculating the expected grid connection point voltage based on the grid-connected active power, the ultra-short-term predicted power, and the grid connection point voltage model includes: Based on the grid-connected active power and the ultra-short-term predicted power, calculate the expected grid-connected active power; Based on the expected grid-connected active power and the grid connection point voltage model, the expected grid connection point voltage is calculated.

7. The method for monitoring the status of new energy power generation according to claim 1, characterized in that, The step of determining the reactive power output mode of the generator set and the energy storage device during the predicted time period includes: If the reactive power output is such that both the generator set and the energy storage device output capacitive reactive power, then the capacitive reactive power output by the energy storage device and the generator set is reduced sequentially until the energy storage device and the generator set stop outputting reactive power, and then the inductive reactive power of the generator set and the energy storage device is increased sequentially. If the reactive power output is such that both the generator set and the energy storage device output inductive reactive power, then the inductive reactive power output by the energy storage device and the generator set is reduced sequentially until the energy storage device and the generator set stop outputting reactive power, and then the capacitive reactive power of the generator set and the energy storage device is increased sequentially.

8. A new energy power generation status monitoring system, employing the new energy power generation status monitoring method as described in any one of claims 1 to 7, characterized in that, The system includes: The module is used to obtain the equivalent power source voltage vector of the power grid, the equivalent resistance of the power grid, the equivalent inductance of the power grid, and the grid-connected active power of the new energy combined power station, and to construct the grid connection point voltage model of the new energy combined power station, which includes generator sets, energy storage devices, several compensation devices, and induction filter transformers. The limiting module is used to obtain the ultra-short-term predicted power, the prediction period corresponding to the ultra-short-term predicted power, the allowable range of grid connection point voltage, and the instructions from the power grid dispatch center. Based on the allowable range of grid connection point voltage and the instructions from the power grid dispatch center, the upper limit of grid connection voltage and the lower limit of grid connection voltage are obtained. The judgment module is used to collect the grid connection point voltage of the new energy combined power station, and determine whether the grid connection point voltage exceeds the limit based on the grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage; The first over-limit module is used to, if the grid connection point voltage exceeds the limit and the grid connection point voltage is greater than the upper limit of the grid connection voltage, obtain the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, and the reactive power of several compensation devices, and calculate the first maximum voltage difference based on the grid connection point voltage, the maximum inductive reactive power of the generator set, the maximum inductive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, so as to perform reactive power compensation adjustment according to the first maximum voltage difference and the ultra-short-term predicted power; The second over-limit module is used to obtain the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, and the reactive power of several compensation devices if the grid connection point voltage exceeds the limit and the grid connection point voltage is less than the lower limit of the grid connection voltage. Based on the grid connection point voltage, the maximum capacitive reactive power of the generator set, the maximum capacitive reactive power of the energy storage device, the reactive power of several compensation devices, and the grid connection point voltage model, the second voltage maximum difference is calculated so as to perform reactive power compensation adjustment according to the second voltage maximum difference and the ultra-short-term predicted power. The prediction module is used to calculate the expected grid connection point voltage based on the grid-connected active power, the ultra-short-term predicted power and the grid connection point voltage model if the grid connection point voltage does not exceed the limit, and to determine whether the expected grid connection point voltage exceeds the limit based on the expected grid connection point voltage, the upper limit of the grid connection voltage and the lower limit of the grid connection voltage. The module is configured to, if the expected grid connection point voltage exceeds the limit, obtain the reactive power output of the generator set and the energy storage device at the current moment, so as to determine the reactive power output mode of the generator set and the energy storage device during the predicted period.

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