Fire coal and battery energy storage virtual power plant frequency modulation method based on power and rate cooperative control

Abstract

The invention discloses a fire coal and battery energy storage virtual power plant frequency modulation method based on power and rate cooperative control. The fire coal and battery energy storage virtual power plant frequency modulation method comprises a power cooperative frequency control strategy and a rate cooperative frequency control strategy. According to the power cooperative frequency control strategy, the available power of each coal-fired power generation subsystem and the available power of each battery energy storage subsystem are calculated to carry out proportional distribution on frequency deviation to generate a frequency deviation correction signal, and the frequency deviation correction signal and the frequency deviation are summed and substituted into primary frequency modulation for calculation; power output of the coal-fired power generation subsystem and the battery energy storage subsystem is obtained; according to the rate cooperative frequency control strategy, the actual frequency of a power grid is compared with a frequency standard value 50 Hz, the charge and discharge power of a battery is adjusted in real time through a PID controller, the frequency modulation effect on the power grid is achieved, and power grid frequency fluctuation caused by internal power deviation of the virtual power plant can be responded in a cooperative mode. According to the invention, the power support of the coal-fired power generation subsystem to the power grid frequency is realized, and the adaptive capacity of the battery energy storage subsystem to the power grid frequency fluctuation is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of automatic power generation control of power systems, and specifically relates to a frequency regulation method for a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control, which is suitable for frequency stability control of power grids with a high proportion of renewable energy. Background Art

[0002] In the context of developing a new power system, building a system that supplies and consumes a high proportion of renewable energy has become a core development goal. However, renewable energy generation has inherent characteristics such as high output volatility and poor controllability, which pose a serious challenge to the frequency security and stability of the power system.

[0003] In this context, virtual power plants, as an innovative energy management model, provide effective technical support for ensuring the safe and stable operation of the power grid through their precise frequency regulation capabilities and flexible power control characteristics. Currently, with the rapid development and continuous increase of various frequency regulation units, how to better utilize the large output power of coal-fired power generation subsystems and the rapid frequency response capabilities of battery energy storage subsystems for frequency regulation has become a focus of industry attention. To this end, it is urgent to establish a scientific coordination mechanism that comprehensively considers the available power of different frequency regulation units and the rapid frequency response capabilities of battery energy storage subsystems, and comprehensively improves the virtual power plant's ability to cope with frequency fluctuations by optimizing its operating strategy. Summary of the Invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a frequency regulation method for a virtual power plant of coal-fired and battery energy storage based on coordinated control of power and rate. The frequency regulation method for a virtual power plant of coal-fired and battery energy storage based on coordinated control of power and rate of the present invention fully utilizes the power support capability of the high-power coal-fired power generation subsystem and the rapid response capability of the battery energy storage subsystem to improve the frequency regulation capability of the virtual power plant, and significantly improves the frequency regulation performance of the virtual power plant.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for frequency regulation of a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control, comprising the following steps:

[0007] Step S1: Establish a virtual power plant frequency regulation control model including a coal-fired power generation subsystem and a battery energy storage subsystem to obtain the output power and grid frequency of the coal-fired power generation subsystem and the battery energy storage subsystem;

[0008] Step S2: adopt the rate-coordinated frequency control strategy, and calculate the output power correction signal of the battery energy storage subsystem after the rate-coordinated frequency control strategy through the PID controller; at the same time, determine whether the power-coordinated frequency control strategy needs to be adopted according to the difference between the grid frequency and the standard frequency of 50Hz. If the absolute value of the difference is greater than 0.03Hz, then adopt the power-coordinated frequency control strategy and the rate-coordinated frequency control strategy at the same time, calculate the frequency deviation correction signal of the coal-fired power generation subsystem and the battery energy storage subsystem according to the available power, and bring the calculated frequency deviation correction signal into the primary frequency modulation calculation to obtain the output power correction signal of the coal-fired power generation subsystem and the output power correction signal of the battery energy storage subsystem respectively; if the absolute value of the difference is less than or equal to 0.03Hz, then do not adopt the power-coordinated frequency control strategy;

[0009] Step S3: Summing the output power correction signal of the coal-fired power generation subsystem calculated by the power-coordinated frequency control strategy with the actual output power of the coal-fired power generation subsystem to obtain the output power of the coal-fired power generation subsystem. Summing the output power correction signal of the battery energy storage subsystem calculated by the power-coordinated frequency control strategy, the output power correction signal of the battery energy storage subsystem calculated by the rate-coordinated frequency control strategy, and the actual output power of the battery energy storage subsystem to obtain the output power of the battery energy storage subsystem.

[0010] Step S4: According to the solved output powers of the coal-fired power generation subsystem and the battery energy storage subsystem, the output power of the coal-fired power generation subsystem and the battery energy storage subsystem are dispatched.

[0011] Advantages of the present invention:

[0012] (1) The present invention establishes a power-coordinated frequency control strategy, which updates the frequency deviation correction signal in real time through the available power of the coal-fired power generation subsystem and the battery energy storage subsystem, and adds it to the primary frequency modulation for calculation. This can more effectively utilize the coal-fired power generation subsystem with larger available power, thereby achieving maximum utilization of the frequency modulation unit.

[0013] (2) This invention establishes a rate-coordinated frequency control strategy, employing a PID controller to calculate the power correction signal of the battery energy storage subsystem. Through precise data feedback and regulation, the battery energy storage subsystem can flexibly respond to changes such as external load disturbances, ensuring the safe and stable operation of the virtual power plant. This control strategy better utilizes the rapid frequency response capability of the battery energy storage subsystem and further optimizes the utilization efficiency of the frequency-regulating units.

[0014] (3) The present invention scientifically combines the above two frequency regulation strategies, which not only effectively utilizes the high-power coal-fired power generation subsystem to effectively support the grid frequency, but also realizes the rapid response of the battery energy storage subsystem to changes in the grid frequency, greatly improving the frequency regulation capability of the virtual power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of the frequency regulation method of a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control proposed by the present invention.

[0016] Figure 2 This is the operating logic diagram of the PID controller of the rate coordinated frequency control strategy proposed in the present invention. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown in the figure, a method for frequency regulation of a coal-fired and energy storage virtual power plant based on coordinated power and rate control takes advantage of the high power characteristics of the coal-fired power generation subsystem to enable it to output more power during the frequency regulation process, thereby improving the power support capacity of the coal-fired power generation subsystem. The battery energy storage subsystem's ability to quickly respond to frequency fluctuations is fully utilized during the frequency regulation process, thereby maximizing the utilization of the coal-fired power generation subsystem and the battery energy storage subsystem. The specific steps of a method for frequency regulation of a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control are as follows:

[0019] Step S1: Establish a virtual power plant frequency regulation control model including a coal-fired power generation subsystem and a battery energy storage subsystem to obtain the output power and grid frequency of the coal-fired power generation subsystem and the battery energy storage subsystem.

[0020] Step S2: By comparing the actual frequency of the power grid with the standard frequency value of 50Hz, the power correction signal P of the battery energy storage subsystem is calculated by the PID controller. bess * At the same time, the control system determines whether to adopt the power coordinated frequency control strategy based on the difference between the grid frequency and the standard frequency of 50Hz. If the absolute value of the difference is less than or equal to 0.03Hz, only the rate coordinated frequency control strategy is adopted, and the power coordinated frequency control strategy is not adopted; if the absolute value of the difference is greater than 0.03Hz, both the power coordinated frequency control strategy and the rate coordinated frequency control strategy are adopted;

[0021] The operating logic of the rate coordinated frequency control strategy PID controller is as follows:

[0022] like Figure 2As shown, the real-time frequency of the power grid is transmitted to the PID controller. The PID controller determines whether the power grid frequency is in a steady state of 50Hz, and then adjusts the output power of the battery energy storage subsystem. The final output power of the battery energy storage subsystem is obtained by adding the power correction signal calculated by the power coordinated frequency control strategy. The calculated output power of the battery energy storage subsystem is used to dispatch the power of the battery energy storage subsystem, affecting the power grid frequency. If the absolute value of the power grid frequency deviation is greater than 0.03Hz, the frequency deviation correction signal of the coal-fired power generation subsystem and the battery energy storage subsystem is calculated based on the available power:

[0023]

[0024]

[0025] Where: Δf coal is the frequency deviation correction signal of the coal-fired power generation system, Hz; Δf bess is the frequency deviation correction signal of the battery energy storage subsystem, Hz; Δf sys is the grid frequency deviation, Hz; ΔP coal is the available power of the coal-fired power generation system, Hz; ΔP bess is the available power of the battery energy storage subsystem, Hz;

[0026] Step S3: Substitute the power deviation correction signal calculated above into a frequency modulation calculation to obtain the output power signal of the coal-fired power generation subsystem and the output power signal of the battery energy storage subsystem:

[0027] P coal '=(Δf sys +Δf coal )×P coal

[0028] P bess '=(Δf sys +Δf bess )×P bess

[0029] Where: P coal ' is the output power correction signal of the coal-fired power generation system after the power coordinated frequency control strategy, MW; P bess ' is the output power correction signal of the battery energy storage subsystem after the power coordinated frequency control strategy, MW; Δf coal is the frequency deviation correction signal of the coal-fired power generation system, Hz; Δf bess is the frequency deviation correction signal of the battery energy storage subsystem, Hz; Δf sys is the grid frequency deviation, Hz; P coal is the rated power of the coal-fired power generation system, MW; P bessis the rated power of the battery energy storage subsystem, MW.

[0030] The output power of the coal-fired power generation subsystem is obtained by summing the power output signals obtained from the above calculations:

[0031] P newcoal =P coal '+P coal

[0032] Where: P newcoal Output power of the updated coal-fired power generation system, MW; P coal ' is the frequency output power correction signal of the coal-fired power generation system calculated by the power coordinated frequency control strategy, MW; P coal is the output power of the current coal-fired power generation system, MW.

[0033] The output power of the battery energy storage subsystem is obtained as:

[0034] P newbess =P bess '+P bess * +P bess

[0035] Where: P newbess Output power of the updated coal-fired power generation system, MW; P bess ' is the frequency output power correction signal of the battery energy storage subsystem calculated by the power coordinated frequency control strategy, MW; P bess * is the frequency output power correction signal of the battery energy storage subsystem calculated by the rate coordinated frequency control strategy, MW; P bess is the current output power of the battery energy storage subsystem, MW.

[0036] Step S4: According to the solved output powers of the coal-fired power generation subsystem and the battery energy storage subsystem, the output power of the coal-fired power generation subsystem and the battery energy storage subsystem are dispatched.

[0037] In summary, the method of the present invention includes a power-coordinated frequency control strategy and a rate-coordinated frequency control strategy. The power-coordinated frequency control strategy calculates the available power of each coal-fired power generation subsystem and the battery energy storage subsystem to proportionally distribute the frequency deviation to generate a frequency deviation correction signal. Finally, the frequency deviation correction signal is summed with the frequency deviation and brought into the primary frequency modulation for calculation to obtain the power output of the coal-fired power generation subsystem and the battery energy storage subsystem; the rate-coordinated frequency control strategy compares the actual frequency of the power grid with the frequency standard value of 50Hz, and adjusts the battery charging and discharging power in real time through PID control to achieve the effect of power grid frequency modulation, which can coordinately respond to power grid frequency fluctuations caused by power deviations within the virtual power plant. The present invention not only realizes the power support of the coal-fired power generation subsystem for the power grid frequency, but also significantly improves the adaptability of the battery energy storage subsystem to power grid frequency fluctuations. This method fully utilizes the high-power characteristics of the coal-fired power generation subsystem and the fast frequency response characteristics of the battery energy storage subsystem, and provides an innovative solution for maximizing the utilization of each frequency modulation unit in the frequency modulation process. It has important practical value and broad market application potential. The present invention dynamically adjusts the real-time output power of the coal-fired power generation subsystem and the battery energy storage subsystem according to the fluctuation of the grid frequency, so as to quickly restore the grid frequency, maintain the grid stability and improve the security of the grid.

Claims

1. A frequency modulation method for a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control, characterized in that: The following steps are involved: Step S1: Establish a virtual power plant frequency regulation control model including a coal-fired power generation subsystem and a battery energy storage subsystem to obtain the output power and grid frequency of the coal-fired power generation subsystem and the battery energy storage subsystem; Step S2: adopt the rate coordinated frequency control strategy, and calculate the output power correction signal of the battery energy storage subsystem through the rate coordinated frequency control strategy through the PID controller; at the same time, judge whether it is necessary to adopt the power coordinated frequency control strategy based on the difference between the grid frequency and the standard frequency of 50Hz. If the absolute value of the difference is greater than 0.03Hz, the power coordinated frequency control strategy and the rate coordinated frequency control strategy are adopted at the same time. The frequency deviation correction signal of the coal-fired power generation subsystem and the battery energy storage subsystem is calculated according to the available power, and the calculated frequency deviation correction signal is brought into the primary frequency modulation calculation to obtain the output power correction signal of the coal-fired power generation subsystem and the battery energy storage subsystem. The energy storage subsystem output power correction signal; if the absolute value of the difference is less than or equal to 0.03Hz, the power coordinated frequency control strategy is not adopted; Step S3: summing the output power correction signal of the coal-fired power generation subsystem calculated by the power coordinated frequency control strategy and the actual output power of the coal-fired power generation subsystem to obtain the output power of the coal-fired power generation subsystem; summing the output power correction signal of the battery energy storage subsystem calculated by the power coordinated frequency control strategy, the output power correction signal of the battery energy storage subsystem calculated by the rate coordinated frequency control strategy, and the actual output power of the battery energy storage subsystem to obtain the output power of the battery energy storage subsystem; Step S4: According to the solved output powers of the coal-fired power generation subsystem and the battery energy storage subsystem, the output power of the coal-fired power generation subsystem and the battery energy storage subsystem are dispatched.

2. A method for frequency modulation of a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control according to claim 1, characterized in that: The power coordinated frequency control strategy and rate coordinated frequency control strategy described in step S2, the power coordinated frequency control strategy calculates the output power signal through the available power of the coal-fired power generation subsystem and the battery energy storage subsystem, and the rate coordinated frequency control strategy controls the output power signal of the battery energy storage subsystem through PID.

3. The method for frequency modulation of a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control according to claim 1, characterized in that: In step S2, if the absolute value of the grid frequency deviation is greater than 0.03 Hz, the frequency deviation correction signal of the coal-fired power generation subsystem and the battery energy storage subsystem is calculated based on the available power: Where: Δf coal is the frequency deviation correction signal of the coal-fired power generation system, Hz; Δf bess is the frequency deviation correction signal of the battery energy storage subsystem, Hz; Δf sys is the grid frequency deviation, Hz; ΔP coal is the available power of the coal-fired power generation system, MW; ΔP bess is the available power of the battery energy storage subsystem, MW.

4. The method for frequency modulation of a coal-fired and battery energy storage virtual power plant based on coordinated power and rate control according to claim 1, characterized in that: In step S2, the calculated frequency deviation correction signal is brought into the primary frequency modulation calculation to obtain the output power signals of the coal-fired power generation subsystem and the battery energy storage subsystem respectively: P coal '=(Δf sys +Δf coal )×P coal P bess '=(Δf sys +Δf bess )×P bess Where: P coal ' is the output power correction signal of the coal-fired power generation system after the power coordinated frequency control strategy, MW; P bess ' is the output power correction signal of the battery energy storage subsystem after the power coordinated frequency control strategy, MW; Δf coal is the frequency deviation correction signal of the coal-fired power generation system, Hz; Δf bess is the frequency deviation correction signal of the battery energy storage subsystem, Hz; Δf sys is the grid frequency deviation, Hz; P coal is the rated power of the coal-fired power generation system, MW; P bess is the rated power of the battery energy storage subsystem, MW.

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