Energy storage power station operation control method, device, equipment and medium

Abstract

The invention relates to the field of energy storage grid-connected control, and discloses an energy storage power station operation control method, device and equipment and a medium. After the energy storage power station is connected to the power grid, the operation condition of the power grid can be monitored according to the electrical quantity of the grid-connected point of the energy storage power station, and when it is monitored that the operation condition of the power grid changes and enters a steady state from the changed condition, the reactive disturbance instruction is sent to the power grid to disturb the electrical quantity of the grid-connected point of the energy storage power station. Determining the short-circuit ratio and harmonic content of the grid-connected point of the energy storage power station according to the disturbed electrical quantity of the grid-connected point of the energy storage power station, and when the short-circuit ratio is smaller than a short-circuit ratio threshold value and the harmonic content is larger than a harmonic content threshold value, performing proportional distribution on the grid-following capacity and the grid-constructing capacity of the energy storage power station according to the short-circuit ratio, and the operation safety and stability of the energy storage power station are enhanced.

Description

Technical Field

[0001] The present invention relates to the field of energy storage grid-connected control, and in particular to an energy storage power station operation control method, device, equipment and medium. Background Art

[0002] With the increase in the scale of new energy power generation such as photovoltaic and wind power, they gradually occupy an important position in the power grid. New energy power generation is random and volatile, which will affect the stable operation of the power grid.

[0003] In order to reduce the impact of renewable energy generation on the power grid, energy storage power stations can be connected to the power grid. Specifically, energy storage power stations can absorb excess energy from the power grid when the renewable energy generation in the power grid is large, and release energy when the renewable energy generation is insufficient, effectively reducing the impact of renewable energy generation on the power grid.

[0004] However, after being connected to the grid, the energy storage power station will also be affected by the grid and have the problem of insufficient stability. Summary of the invention

[0005] The present invention provides an energy storage power station operation control method, device, equipment and medium, which are used to solve the defect of insufficient stability of the energy storage power station due to the influence of the power grid in the related technology, and improve the operation stability of the energy storage power station.

[0006] In a first aspect, the present invention provides an energy storage power station operation control method, comprising: According to the electrical quantity of the energy storage power station grid connection point, if it is monitored that the operating condition of the power grid has changed and entered a steady state from the changed condition, a reactive disturbance instruction is sent to the power grid to disturb the electrical quantity of the energy storage power station grid connection point; wherein the energy storage power station grid connection point is the connection point between the energy storage power station and the power grid; Collecting the disturbed electrical quantities of the energy storage power station grid connection point, and determining the short circuit ratio and harmonic content of the energy storage power station grid connection point according to the disturbed electrical quantities; Determining that the short-circuit ratio is less than a preset short-circuit ratio threshold and the harmonic content is greater than a preset harmonic content threshold, proportionally allocating the grid-following capacity and the grid-building capacity of the energy storage power station based on the short-circuit ratio; If it is determined that the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is greater than the harmonic content threshold, return to execute the step of sending a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point until the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is not greater than the harmonic content threshold.

[0007] Optionally, the monitoring of changes in the operating conditions of the power grid based on the electrical quantity of the energy storage power station grid connection point includes: Periodically collecting the electrical quantity of the energy storage power station grid connection point; When the electrical quantity of the energy storage power station grid connection point is collected each time, the effective value of the voltage and the harmonic content of the energy storage power station grid connection point are determined according to the collected electrical quantity; If the determined voltage effective value is greater than a preset voltage threshold, or the determined harmonic content is greater than the harmonic content threshold, it is determined that the operating condition of the power grid has changed.

[0008] Optionally, monitoring that the power grid enters a steady state from a changed operating condition according to the electrical quantity of the energy storage power station grid connection point includes: If N consecutive voltage change values ​​are all smaller than a preset change threshold, it is determined that the power grid enters a steady state from the changed operating condition; wherein the voltage change value is the absolute value of the difference between the effective voltage value collected this time and the effective voltage value collected last time.

[0009] Optionally, the proportional allocation of the grid-following capacity and the grid-building capacity of the energy storage power station based on the short-circuit ratio includes: determining a relative weakness of the power grid based on the short circuit ratio; Calculate 1 minus the relative weakness of the power grid to obtain a target difference; Determine the relative weakness of the power grid and the target difference as a network construction capacity allocation ratio and a network following capacity allocation ratio respectively; The grid-following capacity and the grid-building capacity of the energy storage power station are proportionally allocated according to the total capacity of the converters of the energy storage power station, the grid-building capacity allocation ratio and the grid-following capacity allocation ratio.

[0010] Optionally, determining the relative weakness of the power grid based on the short-circuit ratio includes: Subtract the short circuit ratio from the short circuit ratio threshold to obtain a short circuit ratio difference; The ratio of the short-circuit ratio difference to the short-circuit ratio threshold is calculated and used as the relative weakness of the power grid.

[0011] Optionally, after determining the short-circuit ratio and harmonic content of the energy storage power station grid connection point according to the post-disturbance electrical quantity, the method further includes: If it is determined that the short-circuit ratio of the energy storage power station grid-connected point is not less than the short-circuit ratio threshold, or the harmonic content of the energy storage power station grid-connected point is not greater than the harmonic content threshold, then the step of collecting the disturbed electrical quantity of the energy storage power station grid-connected point is returned to.

[0012] Optionally, after determining the voltage effective value and harmonic content of the energy storage power station grid connection point according to the collected electrical quantity, the method further includes: If the determined voltage effective value is not greater than the preset voltage threshold, or the determined harmonic content is greater than the harmonic content threshold, it is determined that the operating condition of the power grid has not changed; After determining that the operating condition of the power grid has changed, the method further includes: If at least one of the N consecutive voltage change values ​​is not less than the preset change threshold, it is determined that the power grid has not entered a steady state.

[0013] In a second aspect, the present invention provides an energy storage power station operation control device, comprising: The command sending unit is used to send a reactive disturbance command to the power grid to disturb the electrical quantity of the energy storage power station grid connection point, based on the electrical quantity of the energy storage power station grid connection point, if it is monitored that the operating condition of the power grid has changed and entered a steady state from the changed condition; wherein the energy storage power station grid connection point is the connection point between the energy storage power station and the power grid; A collection unit, used to collect the post-disturbance electrical quantity of the energy storage power station grid connection point; A first determination unit is used to determine the short circuit ratio and harmonic content of the energy storage power station grid connection point according to the post-disturbance electrical quantity; A proportional allocation unit, configured to determine that the short-circuit ratio is less than a preset short-circuit ratio threshold and the harmonic content is greater than a preset harmonic content threshold, and then proportionally allocate the grid-following capacity and the grid-building capacity of the energy storage power station based on the short-circuit ratio; The second determination unit is used to determine that the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is greater than the harmonic content threshold, and then return to execute the step of sending a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point until the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is not greater than the harmonic content threshold.

[0014] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the energy storage power station operation control method of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the energy storage power station operation control method of the first aspect or any corresponding embodiment thereof.

[0016] The energy storage power station operation control method, device, equipment and medium provided by the present invention can monitor the operating condition of the power grid according to the electrical quantity of the energy storage power station grid connection point after the energy storage power station is connected to the power grid, and when it is monitored that the operating condition of the power grid has changed and entered a steady state from the changed condition, send a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point, determine the short-circuit ratio and harmonic content of the energy storage power station grid connection point according to the disturbed electrical quantity of the energy storage power station grid connection point, and when it is determined that the short-circuit ratio is less than the short-circuit ratio threshold and the harmonic content is greater than the harmonic content threshold, proportionally allocate the grid-following capacity and the grid-building capacity of the energy storage power station according to the short-circuit ratio, thereby enhancing the operating safety and stability of the energy storage power station. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A flow chart of an energy storage power station operation control method provided by an embodiment of the present invention; Figure 2 A topological diagram of an energy storage power station connected to a power grid provided in an embodiment of the present invention; Figure 3 A flowchart of another energy storage power station operation control method provided by an embodiment of the present invention; Figure 4 A schematic diagram of the structure of an energy storage power station operation control device provided by an embodiment of the present invention; Figure 5 A schematic diagram of the structure of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] According to different operating modes, the control system of energy storage power stations can be divided into grid-following energy storage (GFL-ES) and grid-forming energy storage (GFM-ES). The two have the same hardware topology but different control methods.

[0021] Grid-connected energy storage is essentially equivalent to a current source. It uses grid voltage-oriented vector control and needs to lock the grid voltage phase through a phase locked loop (PLL) to control the dq axis current vector phase to complete grid-connected power regulation. Due to the dependence of grid-connected energy storage on grid voltage, sub- / super-synchronous oscillation problems are easily caused when the grid strength is weak.

[0022] Grid-connected energy storage is essentially equivalent to a voltage source. It can establish voltage and frequency by itself using a virtual synchronous machine control strategy. It has the ability to adjust frequency and control voltage, is less dependent on the grid, and can be used in weak grids or island conditions. However, in strong grid conditions, it increases the difficulty of control and is prone to instability problems.

[0023] The inventor of the present invention has found that the prerequisite for selecting the ratio of grid-following and grid-building energy storage capacity in energy storage power stations is to determine the strength of the regional power grid. The strength of the power grid is generally measured by the short-circuit ratio. With the large-scale access of new energy power electronic equipment, the operating conditions of the regional power grid are complex, and the strength of the power grid will also change. Therefore, it is necessary to calculate the short-circuit ratio at the grid connection point of the energy storage power station in real time and allocate the grid-following and grid-building capacity of the energy storage system to ensure the safe and stable operation of the energy storage system.

[0024] Combine the following Figure 1-Figure 3 The energy storage power station operation control method of the present invention is described.

[0025] like Figure 1 As shown, this embodiment proposes a first energy storage power station operation control method, which may include the following steps: S101. According to the electrical quantity of the energy storage power station grid connection point, if it is monitored that the operating condition of the power grid has changed and entered a steady state from the changed condition, a reactive disturbance instruction is sent to the power grid to disturb the electrical quantity of the energy storage power station grid connection point. The energy storage power station grid connection point is the connection point between the energy storage power station and the power grid.

[0026] Among them, the electrical quantities at the grid connection point of the energy storage power station may include physical parameters such as instantaneous voltage and instantaneous current.

[0027] Specifically, this embodiment can collect the electrical quantity of the energy storage power station grid connection point, and monitor the operating condition of the power grid according to the electrical quantity of the energy storage power station grid connection point. When it is monitored that the operating condition of the power grid has changed and the changed condition enters a steady state, this embodiment can send a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point.

[0028] Optionally, based on the electrical quantity of the energy storage power station grid connection point, changes in the operating conditions of the power grid are monitored, including: Periodically collect the electrical quantity of the energy storage power station grid connection point; When the electrical quantity of the energy storage power station grid connection point is collected each time, the voltage effective value and harmonic content of the energy storage power station grid connection point are determined according to the collected electrical quantity; If the determined voltage effective value is greater than a preset voltage threshold, or the determined harmonic content is greater than a harmonic content threshold, it is determined that the operating condition of the power grid has changed.

[0029] The electrical quantity of the energy storage power station grid connection point may include at least one of the power parameters such as instantaneous voltage value, instantaneous current value, active power, reactive power and effective voltage value.

[0030] The preset voltage threshold and harmonic content threshold may be set by technicians according to actual conditions, and are not limited in this embodiment.

[0031] Specifically, this embodiment can continuously monitor the electrical quantity of the energy storage power station grid connection point, and continuously determine the voltage effective value and harmonic content of the energy storage power station grid connection point based on the monitored electrical quantity.

[0032] Optionally, the grid enters a steady state from a changed operating condition based on the electrical quantity at the grid connection point of the energy storage power station, including: If N consecutive voltage change values ​​are all smaller than the preset change threshold, it is determined that the power grid has entered a steady state from the changed operating condition; wherein the voltage change value is the absolute value of the difference between the effective voltage value collected this time and the effective voltage value collected last time.

[0033] Specifically, in this embodiment, after determining that the operating condition of the power grid has changed, the newly determined voltage effective value A1 can be subtracted from the previously determined voltage effective value A0 to obtain a voltage change value. If the voltage change value is less than the preset change threshold, the voltage effective value A2 can be determined next time, and then the voltage effective value A2 can be subtracted from the voltage effective value A1 to obtain another voltage change value, until N voltage change values ​​are obtained. If the consecutive N voltage change values ​​are all less than the preset change threshold, it can be determined that the power grid has entered a stable condition again from the changed condition.

[0034] Optionally, in other energy storage power station operation control methods proposed in this embodiment, after determining the voltage effective value and harmonic content of the energy storage power station grid connection point according to the collected electrical quantities, the following method may also be included: If the determined voltage effective value is not greater than the preset voltage threshold, or the determined harmonic content is greater than the harmonic content threshold, it is determined that the operating condition of the power grid has not changed; After determining that the operating condition of the power grid has changed, the method further includes: If at least one of the N consecutive voltage change values ​​is not less than a preset change threshold, it is determined that the power grid has not entered a steady state.

[0035] It can be understood that, in this embodiment, when determining whether the power grid has re-entered the stable operating condition from the changed operating condition, if a certain voltage change value calculated is greater than the preset change threshold, it can be determined that the power grid has not yet entered the stable operating condition.

[0036] It should be noted that, after determining that the operating condition of the power grid has changed, this embodiment can continuously monitor the effective value of the voltage at the grid connection point of the energy storage power station and continuously calculate the voltage change value. As long as it is determined that N consecutive voltage change values ​​are all less than the preset change threshold, it is determined that the power grid has entered a steady state from the changed condition.

[0037] This embodiment can be applied to the control system of an energy storage power station. Figure 2 As shown in the figure, the control system of the energy storage power station mainly includes four functions, namely, electrical quantity collection and calculation, operating condition change judgment, short-circuit capacity and short-circuit ratio calculation, and control command communication. The control system can collect the instantaneous values ​​of the three-phase voltage and three-phase current of the energy storage power station grid connection point in real time, and calculate the real-time active power, reactive power, voltage effective value and harmonic content of the energy storage power station grid connection point. When the voltage effective value of the energy storage power station grid connection point exceeds the preset voltage threshold or the harmonic content exceeds the harmonic content threshold, it is judged that the grid operation condition has changed, and the new grid condition will enter a steady state.

[0038] Among them, this embodiment continuously calculates the effective value of the grid voltage in real time, starts counting when it is determined that the grid operating conditions have changed, and when it is determined that the difference between two adjacent calculation results is less than the threshold Q. After the difference between the calculation results for C consecutive times is less than the threshold Q, it can be determined that the grid has entered a steady state.

[0039] Specifically, this embodiment can actively send a reactive disturbance instruction to the power grid, that is, actively inject a certain amount of reactive power into the power grid. The injected reactive power will cause changes in the grid voltage and related electrical quantities.

[0040] S102, collecting the post-disturbance electrical quantity of the energy storage power station grid connection point.

[0041] Specifically, the post-disturbance electrical quantity of the grid-connected point of the energy storage power station is the electrical quantity of the grid-connected point of the energy storage power station after the reactive power disturbance is applied to the power grid.

[0042] S103. Determine the short-circuit ratio and harmonic content of the energy storage power station grid connection point based on the electrical quantity after the disturbance.

[0043] like Figure 2 The topological diagram of the new energy and energy storage power station connected to the power grid is shown. The energy storage power station is equipped with a control device and multiple energy storage converters (Power Conversion System, PCS). This embodiment can collect the electrical quantity of the grid connection point, that is, the electrical quantity of the grid connection point of the energy storage power station. L s and R s They are the grid equivalent reactance and grid equivalent resistance respectively, and the two are combined into the grid equivalent impedance Z s , E s is the equivalent electromotive force of the power grid.

[0044] It should be noted that the following formula (1) can be derived from Kirchhoff's law and the Pythagorean theorem of triangles: .

[0045] in, , and They are voltage RMS, active power and reactive power respectively.

[0046] Under different working conditions of the power grid, according to the electrical quantities collected and calculated under the steady state of the working conditions at that time {( U 1, P 1, Q 1), ( U 2, P 2, Q 2), ( U 3. P 3. Q 3), … ( U n , P n , Q n )}, multiple groups of electrical quantities are substituted into formula (1) to establish redundant equations, and the least squares method is used to fit and solve them, and the equivalent electromotive force of the grid in steady state can be obtained: E s and grid equivalent impedance Z s The short-circuit capacity of the energy storage power station grid connection point is equal to the three-phase short-circuit current at that point and the rated voltage ( U N), that is, formula (2): .

[0047] Short circuit ratio (SCR) is the short circuit capacity of the system Capacity of electrical equipment The ratio between them is formula (3): .

[0048] It should be noted that, in this embodiment, after a certain amount of reactive power is injected into the power grid, the injected reactive power will cause the power grid voltage and other quantities in formula (1) to change. The electrical quantities before and after the reactive power injection can be collected and then calculated using formula (1). The short-circuit ratio is calculated using the least squares method combined with formulas (1), (2) and (3) based on the electrical quantities before and after the disturbance.

[0049] S104: If it is determined that the short-circuit ratio is less than a preset short-circuit ratio threshold and the harmonic content is greater than a preset harmonic content threshold, the grid-following capacity and the grid-building capacity of the energy storage power station are proportionally allocated based on the short-circuit ratio.

[0050] The short circuit ratio threshold may be a critical short circuit ratio set by a technician according to actual conditions.

[0051] It should be noted that this embodiment can solve the grid equivalent impedance and equivalent electromotive force of the energy storage power station grid connection point based on the least squares method, so as to calculate the corresponding short-circuit ratio, and according to the real-time value of the short-circuit ratio and harmonic content, perform capacity allocation for different operation modes of the energy storage PCS following the grid and building the grid.

[0052] Specifically, this embodiment can determine that the grid characteristic is a weak grid when it is determined that the short-circuit ratio is less than the short-circuit ratio threshold, and when it is determined that the harmonic content is greater than the harmonic content threshold, it is determined that the allocation of the grid-following capacity and the grid-forming capacity in the energy storage power station is unreasonable. At this time, the total capacity of the energy storage converter of the energy storage power station can be proportionally allocated according to the short-circuit ratio.

[0053] It should be noted that, in this embodiment, when allocating the energy storage capacity ratio, the control object is not limited to the energy storage converter, but may be extended to power electronic devices such as wind turbine converters and photovoltaic inverters that support both grid-following and grid-building modes as needed.

[0054] Optionally, the grid-following capacity and grid-building capacity of the energy storage power station are proportionally allocated based on the short-circuit ratio, including: Determine the relative weakness of the grid based on the short-circuit ratio; Calculate 1 minus the relative weakness of the grid to get the target difference; The relative weakness of the power grid and the target difference are determined as the capacity allocation ratio of the network construction and the capacity allocation ratio of the network following respectively; According to the total capacity of the converters of the energy storage power station, the allocation ratio of the grid-building capacity and the allocation ratio of the grid-following capacity, the grid-following capacity and the grid-building capacity of the energy storage power station are proportionally allocated.

[0055] Optionally, the determining of the relative weakness of the power grid based on the short-circuit ratio includes: Subtract the short circuit ratio from the short circuit ratio threshold to obtain the short circuit ratio difference; The ratio of the short-circuit ratio difference to the short-circuit ratio threshold is calculated and used as the relative weakness of the power grid.

[0056] It should be noted that under a strong power grid, the grid-following PCS can better ensure the stability of the power grid system. However, due to the large-scale access of new energy power electronic equipment, the equivalent impedance of the power grid changes, which in turn causes the short-circuit ratio to change. After the power grid presents the characteristics of a weak power grid, the grid-following PCS is not conducive to ensuring the stability of the weak power grid. On the contrary, the grid-building PCS is essentially equivalent to a voltage source. It can establish voltage and frequency by itself using a virtual synchronous machine control strategy. It has the ability to regulate frequency and control voltage, and is less dependent on the power grid. It can be applied to weak power grids or island conditions. Therefore, when the power grid becomes weak, the original grid-following energy storage needs to change the control strategy. After becoming a grid-building energy storage, the stability of the system can be enhanced. This embodiment allocates the grid-building and grid-following capacity to the total capacity of the PCS of the energy storage power station according to the short-circuit ratio and harmonic content, which can effectively enhance the operating safety and stability of the energy storage power station.

[0057] Specifically, this embodiment can take a critical short circuit ratio SCR c (i.e. short circuit ratio threshold), when the short circuit ratio is greater than SCR c When the short-circuit ratio is less than SCR c When the grid characteristic is weak, the relative weakness of the grid is defined as P% = ( SCR c - SCR ) / SCR c ,When the short-circuit ratio is used to determine that the power grid is a weak power grid at this time, and it is determined that the harmonic content is greater than the harmonic content threshold, the relative weakness P% of the power grid can be calculated, and P% of the total capacity of the energy storage power station PCS will be operated in the grid-building mode, and the rest will be operated in the grid-following mode. When the short-circuit ratio is small enough, that is, the P% calculation result is approximately equal to 100%, all PCS of the energy storage power station must be operated in the grid-building mode.

[0058] S105. If it is determined that the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is greater than the harmonic content threshold, then return to the above step of sending a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point until the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is not greater than the harmonic content threshold.

[0059] Specifically, in this embodiment, after the grid-following capacity and the grid-building capacity of the energy storage power station are proportionally allocated for the first time, the harmonic content of the grid-connected point of the energy storage power station after the first proportional allocation can be determined, and it can be judged whether the harmonic content of the grid-connected point of the energy storage power station after the first proportional allocation is greater than the harmonic content. If it is determined that the harmonic content of the grid-connected point of the energy storage power station after the first proportional allocation is greater than the harmonic content threshold, it can be determined that the proportional allocation is unreasonable. At this time, the above-mentioned step of collecting the disturbed electrical quantity of the grid-connected point of the energy storage power station can be returned to execute, so as to calculate the short-circuit ratio and the harmonic content of the grid-connected point of the energy storage power station again, and the grid-following capacity and the grid-building capacity of the energy storage power station are proportionally allocated for the second time according to the calculated short-circuit ratio and the harmonic content, until the harmonic content of the grid-connected point of the energy storage power station after the proportional allocation is completed is not greater than the harmonic content threshold.

[0060] Specifically, this embodiment can make a preliminary allocation of capacity for the PCS operation mode of the energy storage power station according to the short-circuit ratio. In order to ensure the rapidity and synchronization of the control instructions, the control instructions are issued in the form of Ethernet control communication. After the initial allocation of capacity, it is necessary to perform the next step of judgment logic again according to the harmonic content. That is, if the harmonic content is not greater than the harmonic content threshold at this time, it proves that the capacity allocation is reasonable and the power grid returns to a stable operation mode. If the harmonic content is still greater than the harmonic content threshold at this time, it proves that the capacity allocation is unreasonable, and it is necessary to recalculate the short-circuit ratio at this time and perform a secondary allocation until the harmonic content of the energy storage power station grid connection point is not greater than the harmonic content threshold after the proportional allocation is completed.

[0061] It should be noted that this embodiment can increase the access capacity of new energy grid-connected capacity and improve the stability of regional power grids by flexibly adjusting the operation of different energy storage modes. The control function of the energy storage power station can be integrated into the coordination controller used in the energy storage power station, making the coordination controller more functional without increasing the hardware cost.

[0062] The energy storage power station operation control method proposed in this embodiment can monitor the operation condition of the power grid according to the electrical quantity of the energy storage power station grid connection point after the energy storage power station is connected to the power grid, and when it is monitored that the operation condition of the power grid has changed and entered a steady state from the changed condition, send a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point, determine the short-circuit ratio and harmonic content of the energy storage power station grid connection point according to the disturbed electrical quantity of the energy storage power station grid connection point, and when it is determined that the short-circuit ratio is less than the short-circuit ratio threshold and the harmonic content is greater than the harmonic content threshold, proportionally allocate the grid-following capacity and the grid-building capacity of the energy storage power station according to the short-circuit ratio, so as to enhance the operation safety and stability of the energy storage power station.

[0063] based on Figure 1 This embodiment proposes a second energy storage power station operation control method. After determining the short-circuit ratio and harmonic content of the energy storage power station grid connection point according to the post-disturbance electrical quantity, the method further includes: If it is determined that the short-circuit ratio of the energy storage power station grid connection point is not less than the short-circuit ratio threshold, or the harmonic content of the energy storage power station grid connection point is not greater than the harmonic content threshold, then return to the step of collecting the disturbed electrical quantity of the energy storage power station grid connection point.

[0064] Specifically, in this embodiment, when it is determined that the short-circuit ratio of the energy storage power station grid connection point is not less than the short-circuit ratio threshold, the power grid can be determined to be a strong power grid, and there is no need to adjust the proportion of the grid-following capacity and the grid-building capacity in the energy storage power station.

[0065] Specifically, in this embodiment, when it is determined that the harmonic content of the grid connection point of the energy storage power station is not greater than the harmonic content threshold, it can be determined that the ratio of grid-connected capacity to grid-connected capacity in the energy storage power station is at a reasonable level, and there is no need to adjust the ratio.

[0066] The energy storage power station operation control method proposed in this embodiment can, when it is determined that the short-circuit ratio of the energy storage power station grid connection point is not less than the short-circuit ratio threshold, or when it is determined that the harmonic content of the energy storage power station grid connection point is not greater than the harmonic content threshold, there is no need to adjust the proportional distribution of the grid-following capacity and the grid-building capacity in the energy storage power station, thereby reducing the consumption of proportional distribution resources.

[0067] like Figure 3 As shown, this embodiment proposes a third energy storage power station operation control method, which may include the following steps: S301, collecting the electrical quantity of the energy storage power station grid connection point.

[0068] S302, calculating electrical parameters such as active power, reactive power, voltage effective value and harmonic content of the energy storage power station grid connection point.

[0069] S303: Determine whether the operating condition of the power grid has changed. If not, return to step S302. If yes, execute step S304.

[0070] S304: Determine whether the grid operation condition has entered a steady state. If not, return to step S302. If yes, execute step S305.

[0071] S305, actively send disturbance reactive power instructions to the energy storage PCS, and calculate the equivalent impedance and equivalent electromotive force of the power grid based on the data before and after the disturbance.

[0072] S306: Calculate the short circuit ratio.

[0073] S307, determine whether the short circuit ratio change exceeds the threshold. If not, return to step S306. If yes, execute step S308.

[0074] S308: Determine whether the harmonic content exceeds the threshold. If not, return to step S306. If yes, execute step S309.

[0075] S309. Adjust the capacity ratio of the inverters in the following and forming modes according to the change of the short-circuit ratio.

[0076] S310, the allocation instruction is sent to the energy storage PCS via Ethernet control communication (Ethernet for Control Automation, EtherCAT).

[0077] S311, determine whether the harmonic content exceeds the threshold. If yes, return to step S305. If no, end.

[0078] The energy storage power station operation control method proposed in this embodiment can effectively enhance the operation stability of the energy storage power station.

[0079] like Figure 4 As shown, this embodiment provides an energy storage power station operation control device, including: The instruction sending unit 401 is used to send a reactive disturbance instruction to the grid to disturb the electrical quantity of the energy storage power station grid connection point, based on the electrical quantity of the energy storage power station grid connection point, if it is detected that the operating condition of the grid changes and enters a steady state from the changed condition; wherein the energy storage power station grid connection point is the connection point between the energy storage power station and the grid; A collection unit 402 is used to collect the post-disturbance electrical quantity of the energy storage power station grid connection point; The first determination unit 403 is used to determine the short circuit ratio and harmonic content of the energy storage power station grid connection point according to the post-disturbance electrical quantity; A proportional allocation unit 404 is used to determine that the short-circuit ratio is less than a preset short-circuit ratio threshold and the harmonic content is greater than a preset harmonic content threshold, and then proportionally allocate the grid-following capacity and the grid-building capacity of the energy storage power station based on the short-circuit ratio; The second determination unit 405 is used to determine that the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is greater than the harmonic content threshold, and then return to execute the step of sending a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point until the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is not greater than the harmonic content threshold.

[0080] It should be noted that the processing of the instruction sending unit 401, the collection unit 402, the first determination unit 403, the ratio allocation unit 404 and the second determination unit 405 and the beneficial effects thereof can be respectively referred to in Figure 1 Steps S101 to S105 in the above are not described in detail.

[0081] Optionally, the instruction sending unit 401 is further configured to: Periodically collect the electrical quantity of the energy storage power station grid connection point; When the electrical quantity of the energy storage power station grid connection point is collected each time, the voltage effective value and harmonic content of the energy storage power station grid connection point are determined according to the collected electrical quantity; If the determined voltage effective value is greater than a preset voltage threshold, or the determined harmonic content is greater than a harmonic content threshold, it is determined that the operating condition of the power grid has changed.

[0082] Optionally, the instruction sending unit 401 is further configured to: If N consecutive voltage change values ​​are all smaller than the preset change threshold, it is determined that the power grid has entered a steady state from the changed operating condition; wherein the voltage change value is the absolute value of the difference between the effective voltage value collected this time and the effective voltage value collected last time.

[0083] Optionally, the proportion allocation unit 404 is further configured to: Determine the relative weakness of the grid based on the short-circuit ratio; Calculate 1 minus the relative weakness of the grid to get the target difference; The relative weakness of the power grid and the target difference are determined as the capacity allocation ratio of the network construction and the capacity allocation ratio of the network following respectively; According to the total capacity of the converters of the energy storage power station, the allocation ratio of the grid-building capacity and the allocation ratio of the grid-following capacity, the grid-following capacity and the grid-building capacity of the energy storage power station are proportionally allocated.

[0084] Optionally, the proportion allocation unit 404 is further configured to: Subtract the short circuit ratio from the short circuit ratio threshold to obtain the short circuit ratio difference; The ratio of the short-circuit ratio difference to the short-circuit ratio threshold is calculated and used as the relative weakness of the power grid.

[0085] Optionally, the above device further comprises: The third determination unit is used to determine the short-circuit ratio and harmonic content of the energy storage power station grid-connected point according to the post-disturbance electrical quantity, and determine that the short-circuit ratio of the energy storage power station grid-connected point is not less than the short-circuit ratio threshold, or the harmonic content of the energy storage power station grid-connected point is not greater than the harmonic content threshold, thereby triggering the acquisition unit 402.

[0086] Optionally, the above device further comprises: A fourth determination unit is used to determine the voltage effective value and harmonic content of the energy storage power station grid connection point according to the collected electrical quantity, and if the determined voltage effective value is not greater than a preset voltage threshold, or the determined harmonic content is greater than the harmonic content threshold, determine that the operating condition of the power grid has not changed; The fifth determination unit is used to determine that the power grid has not entered a steady state if at least one of N consecutive voltage change values ​​is not less than a preset change threshold after determining that the operating condition of the power grid has changed.

[0087] The energy storage power station operation control device proposed in this embodiment can monitor the operation condition of the power grid according to the electrical quantity of the energy storage power station grid connection point after the energy storage power station is connected to the power grid, and when it is monitored that the operation condition of the power grid has changed and entered a steady state from the changed condition, send a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point, determine the short-circuit ratio and harmonic content of the energy storage power station grid connection point according to the disturbed electrical quantity of the energy storage power station grid connection point, and when it is determined that the short-circuit ratio is less than the short-circuit ratio threshold and the harmonic content is greater than the harmonic content threshold, proportionally allocate the grid-following capacity and the grid-building capacity of the energy storage power station according to the short-circuit ratio, so as to enhance the operation safety and stability of the energy storage power station.

[0088] The energy storage power station operation control device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0089] The embodiment of the present invention also provides a computer device having the above Figure 4 The energy storage power station operation control device shown.

[0090] See also Figure 5, a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed in the computer device, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 5 A processor 10 is taken as an example.

[0091] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0092] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0093] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function. The data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage devices. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0094] The memory 20 may include a volatile memory, such as a random access memory. The memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive. The memory 20 may also include a combination of the above-mentioned types of memory.

[0095] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0096] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the operation of an energy storage power station, characterized in that: include: According to the electrical quantity of the energy storage power station grid connection point, if it is monitored that the operating condition of the power grid has changed and entered a steady state from the changed condition, a reactive disturbance instruction is sent to the power grid to disturb the electrical quantity of the energy storage power station grid connection point; wherein the energy storage power station grid connection point is the connection point between the energy storage power station and the power grid; Collecting the disturbed electrical quantities of the energy storage power station grid connection point, and determining the short circuit ratio and harmonic content of the energy storage power station grid connection point according to the disturbed electrical quantities; Determining that the short-circuit ratio is less than a preset short-circuit ratio threshold and the harmonic content is greater than a preset harmonic content threshold, proportionally allocating the grid-following capacity and the grid-building capacity of the energy storage power station based on the short-circuit ratio; If it is determined that the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is greater than the harmonic content threshold, return to execute the step of sending a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point until the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is not greater than the harmonic content threshold.

2. The method according to claim 1, characterized in that The above-mentioned monitoring of the operation condition of the power grid based on the electrical quantity of the energy storage power station grid connection point changes includes: Periodically collecting the electrical quantity of the energy storage power station grid connection point; When the electrical quantity of the energy storage power station grid connection point is collected each time, the effective value of the voltage and the harmonic content of the energy storage power station grid connection point are determined according to the collected electrical quantity; If the determined voltage effective value is greater than a preset voltage threshold, or the determined harmonic content is greater than the harmonic content threshold, it is determined that the operating condition of the power grid has changed.

3. The method according to claim 2, characterized in that According to the electrical quantity of the energy storage power station grid connection point, the grid is monitored to enter a steady state from the changed working condition, including: If N consecutive voltage change values ​​are all smaller than a preset change threshold, it is determined that the power grid enters a steady state from the changed operating condition; wherein the voltage change value is the absolute value of the difference between the effective voltage value collected this time and the effective voltage value collected last time.

4. The method according to claim 1, characterized in that: The proportional allocation of the grid-following capacity and the grid-building capacity of the energy storage power station based on the short-circuit ratio includes: determining a relative weakness of the power grid based on the short circuit ratio; Calculate 1 minus the relative weakness of the power grid to obtain a target difference; Determine the relative weakness of the power grid and the target difference as a network construction capacity allocation ratio and a network following capacity allocation ratio respectively; The grid-following capacity and the grid-building capacity of the energy storage power station are proportionally allocated according to the total capacity of the converters of the energy storage power station, the grid-building capacity allocation ratio and the grid-following capacity allocation ratio.

5. The method according to claim 4, characterized in that Determining the relative weakness of the power grid based on the short-circuit ratio includes: Subtract the short circuit ratio from the short circuit ratio threshold to obtain a short circuit ratio difference; The ratio of the short-circuit ratio difference to the short-circuit ratio threshold is calculated and used as the relative weakness of the power grid.

6. The method according to claim 1, characterized in that After determining the short-circuit ratio and harmonic content of the energy storage power station grid connection point according to the post-disturbance electrical quantity, the method further includes: If it is determined that the short-circuit ratio of the energy storage power station grid-connected point is not less than the short-circuit ratio threshold, or the harmonic content of the energy storage power station grid-connected point is not greater than the harmonic content threshold, then the step of collecting the disturbed electrical quantity of the energy storage power station grid-connected point is returned to.

7. The method according to claim 3, characterized in that After determining the voltage effective value and harmonic content of the energy storage power station grid connection point according to the collected electrical quantity, the method further includes: If the determined voltage effective value is not greater than the preset voltage threshold, or the determined harmonic content is greater than the harmonic content threshold, it is determined that the operating condition of the power grid has not changed; After determining that the operating condition of the power grid has changed, the method further includes: If at least one of the N consecutive voltage change values ​​is not less than the preset change threshold, it is determined that the power grid has not entered a steady state.

8. An energy storage power station operation control device, characterized in that: include: The command sending unit is used to send a reactive disturbance command to the power grid to disturb the electrical quantity of the energy storage power station grid connection point, based on the electrical quantity of the energy storage power station grid connection point, if it is monitored that the operating condition of the power grid has changed and entered a steady state from the changed condition; wherein the energy storage power station grid connection point is the connection point between the energy storage power station and the power grid; A collection unit, used to collect the post-disturbance electrical quantity of the energy storage power station grid connection point; A first determination unit is used to determine the short circuit ratio and harmonic content of the energy storage power station grid connection point according to the post-disturbance electrical quantity; A proportional allocation unit, configured to determine that the short-circuit ratio is less than a preset short-circuit ratio threshold and the harmonic content is greater than a preset harmonic content threshold, and then proportionally allocate the grid-following capacity and the grid-building capacity of the energy storage power station based on the short-circuit ratio; The second determination unit is used to determine that the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is greater than the harmonic content threshold, and then return to execute the step of sending a reactive disturbance instruction to the power grid to disturb the electrical quantity of the energy storage power station grid connection point until the harmonic content of the energy storage power station grid connection point after the proportional distribution is completed is not greater than the harmonic content threshold.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the energy storage power station operation control method according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the energy storage power station operation control method according to any one of claims 1 to 7.

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