A wind-solar-storage coordinated frequency regulation optimization control method

Abstract

The present invention relates to a novel wind, light and storage coordinated frequency modulation optimization control method, including: constructing a small microgrid system based on a small wind turbine generator set, rooftop photovoltaic, and electric energy storage device, connecting the small microgrid system to the extended analog quantity IO of the DCS system through hard wiring, and assisting the frequency modulation optimization control of the coal-fired unit through the synergistic effect of wind, light and electric energy storage; based on the energy management system, according to the acquired real-time data signal, using a probability prediction algorithm to evaluate the load space capacity and rate of the generator set and predict the grid frequency, and comprehensively judge, for the frequency modulation compensation with a probability prediction frequency modulation time less than 20s, preferably frequency difference compensation, for the frequency modulation compensation less than 60s, preferably interval electric energy storage compensation. The present invention can ensure the best response of the primary frequency modulation of the coal-fired unit, while reducing the primary frequency modulation hardware requirements of the unit, and compensate for electricity from the perspective of green energy, making full use of green electricity, and effectively reducing dependence on fossil energy.

Description

Technical Field

[0001] The present invention relates to the application field of frequency regulation of coal-fired units, and in particular to a wind-solar-storage coordinated frequency regulation optimization control method. Background Art

[0002] Primary frequency regulation is an important technical guarantee for generator sets to ensure that the grid frequency is stable within the allowable frequency deviation range. The grid relies more on traditional coal-fired units to adjust the grid frequency. At present, the typical technical means of primary frequency regulation optimization rely more on the original turbine rotational inertia, which is quickly compensated by the DEH system according to certain constraints, and then the load is adjusted synchronously through the coordination system to achieve fast and stable regulation. However, due to the inherent characteristics of the unit, the quality of primary frequency regulation cannot meet the adjustment needs and is often subject to grid assessment, which is undoubtedly a further blow to the survival and operation of coal-fired enterprises at this stage.

[0003] In summary, typical primary frequency regulation optimization techniques cannot fundamentally and truly achieve accurate compensation of load adjustment. Summary of the invention

[0004] The purpose of the present invention is to provide a wind-solar-storage coordinated frequency regulation optimization control method, which adopts efficient and fast new energy technology means to assist coal-fired units in implementing precise frequency regulation control, reduce the reciprocating disturbance and pressure fluctuation of the units under traditional primary frequency regulation, and effectively improve the primary frequency regulation response level. At the same time, natural energy such as wind and solar energy are used for energy storage to achieve carbon emissions.

[0005] The present invention provides a wind-solar-storage coordinated frequency regulation optimization control method, comprising the following steps:

[0006] Step 1: Build a small microgrid system based on small wind turbines, rooftop photovoltaics, and electric energy storage devices, and connect the small microgrid system to the extended analog IO of the DCS system through hard wiring to assist the frequency modulation optimization control of coal-fired units through the synergistic effect of wind, light, and electric energy storage;

[0007] Step 2: Based on the energy management system and according to the acquired real-time data signals, a probability prediction algorithm is used to evaluate the load space capacity and rate of the generator set and predict the grid frequency. After comprehensive evaluation, for frequency compensation with probability prediction frequency regulation time less than 20s, frequency difference compensation is preferred, and for frequency compensation less than 60s, interval electric energy storage compensation is preferred.

[0008] Furthermore, the step 2 comprises:

[0009] Take the AGC load instruction Ls, actual power Lr, and grid frequency f, set the sampling period to 1s, extract the PT signal to obtain the actual frequency of the generator outlet, that is, the grid frequency f, and perform dead zone judgment on the signal to determine the positive and negative directions of the frequency modulation. If the grid frequency f>50+δ, the energy management system triggers the charging mechanism, and if the grid frequency f<50-δ, the discharging mechanism is triggered.

[0010] Furthermore, if the grid frequency f>50+δ, the actual load Lr of the unit is lower than the set value Ls, and the grid frequency f is greater than the frequency regulation dead zone δ, the unit starts to reduce the load, and the trend of the grid frequency f is judged based on the built-in algorithm module of the energy management system:

[0011] 1) The adjustment time is within 20s. The generator set is preferably charged to the energy storage device. It is determined that Δ=|Lr-Ls|≤δ, where δ takes a certain limit value, which is automatically calculated by the system. The DCS load instruction remains unchanged. At this time, the frequency regulation function of the DCS system of the unit is cut off. If the energy storage device does not meet the charging conditions, the DCS system frequency regulation mode is used to reduce the load.

[0012] 2) The adjustment time is between 20s and 60s, mainly based on frequency difference adjustment, and the integrated power is calculated in real time. After 10s, the charging mode of the energy storage device is started for 5s. During this period, the load command is locked, and then the DCS system continues to adjust.

[0013] Furthermore, if the grid frequency f>50+δ, the actual load Lr of the unit is higher than the set value Ls, and the grid frequency f is greater than the dead zone δ, the unit starts to increase the load rapidly; the energy management system evaluates the trend of the grid frequency f:

[0014] 1) The adjustment time is within 20s, triggering the charging mechanism of the electric energy storage device, judging Δ=|Lr-Ls|≤δ, δ takes a certain limit value, which is automatically calculated by the system. At this time, the frequency regulation function of the unit DCS system is cut off. If the electric energy storage device does not have the charging conditions, the DCS system frequency regulation mode is used to reduce the load, increase the frequency regulation gain, and superimpose the pressure setting value offset;

[0015] 2) Between 20s and 60s, the frequency difference adjustment is the main focus, with charging of the energy storage device as a supplement.

[0016] Furthermore, if the grid frequency f<50-δ, the actual load Lr of the unit is greater than the set value Ls, and the grid frequency f is less than the dead zone δ, the unit starts to increase the load; the energy management system judges the trend of the grid frequency f:

[0017] 1) Within 20 seconds, the DCS system frequency modulation method is used to increase the load and increase the frequency modulation gain;

[0018] 2) Between 20s and 60s, the real-time load deviation is calculated. At 10s, the wind-solar combined energy storage switch is switched to charge the electric energy storage device. The electric energy storage device quickly compensates the load deviation for 5s. Then, the electric energy storage device performs fixed value compensation based on the deviation β between the load command and the expected target command after DCS superimposed compensation.

[0019] Furthermore, if the grid frequency f<50-δ, the actual load Lr of the unit is less than the set value Ls, the grid frequency f is less than the dead zone δ, and the unit quickly increases the load; the energy management system evaluates the trend of the grid frequency f:

[0020] 1) Within 20 seconds, the discharge mechanism of the electric energy storage device is triggered. At this time, the frequency regulation function of the DCS system of the unit is cut off, and the wind-solar combined energy storage switch is switched to charge the electric energy storage device. If the electric energy storage device does not meet the discharge conditions, the DCS system frequency regulation method is used to increase the load, increase the frequency regulation gain, and superimpose the pressure setting value bias;

[0021] 2) Between 20s and 60s, the frequency difference adjustment is the main focus, with charging of the energy storage device as a supplement.

[0022] Furthermore, when the grid frequency f exceeds the dead zone range, a frequency modulation action is completed, and then the whole process is repeated according to the change of the grid frequency f.

[0023] Through the above scheme, through the wind, light and storage coordinated frequency regulation optimization control method, by building small wind turbines, roof and carport photovoltaics, and integrated electric energy storage in the factory area, the frequency regulation auxiliary compensation of the steam turbine generator set is realized. The control terminal is connected to the real-time data signals such as the actual power of the generator set and the grid frequency. The probability prediction algorithm is used to evaluate the load space capacity and rate of the generator set to increase / decrease and predict the grid frequency. After comprehensive evaluation, for the frequency regulation compensation with a probability prediction frequency regulation time of less than 20s, "frequency difference compensation" is preferred, and for the frequency regulation compensation of less than 60s, "interval electric energy storage compensation" is preferred. Finally, the instantaneous reliable action of the primary frequency regulation of the unit is realized, and the interval stable compensation is used to ensure the stability of the grid frequency. At the same time, the situation of primary frequency regulation being assessed is minimized. Based on the energy management system, the controllable charging of the energy storage device by wind-light complementarity is realized, and the dependence of the energy storage device on the unit's electric energy is minimized. Green energy storage is preferred, the rapid charging and discharging mechanism of the energy storage system is reduced, and the output is smooth and stable, which effectively increases the utilization hours of the energy storage device. The present invention proposes a flexible adjustment strategy for regionalized load compensation, which can ensure the optimal response of the primary frequency regulation of the coal-fired unit, while reducing the demand for the primary frequency regulation hardware of the unit, performing electricity compensation from the perspective of green energy, making full use of green electricity, and effectively reducing dependence on fossil energy, which is of great significance to achieving carbon emission reduction. Effectively reducing dependence on fossil energy is of great significance to achieving carbon emission reduction.

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of an embodiment of the wind-solar-storage coordinated frequency regulation optimization control method of the present invention. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] This embodiment provides a wind-solar-storage coordinated frequency regulation optimization control method, comprising the following steps:

[0028] Step 1: Build a small microgrid system based on small wind turbines, rooftop photovoltaics, and electric energy storage devices, and connect the small microgrid system to the extended analog IO of the DCS system through hard wiring to assist the frequency modulation optimization control of coal-fired units through the synergistic effect of wind, light, and electric energy storage;

[0029] Step 2: Based on the energy management system and according to the acquired real-time data signals, a probability prediction algorithm is used to evaluate the load space capacity and rate of the generator set and predict the grid frequency. After comprehensive evaluation, for frequency compensation with probability prediction frequency regulation time less than 20s, frequency difference compensation is preferred, and for frequency compensation less than 60s, interval electric energy storage compensation is preferred.

[0030] Ginseng Figure 1 As shown, step 2 includes:

[0031] Take the AGC load instruction Ls, actual power Lr, and grid frequency f, set the sampling period to 1s, extract the PT signal to obtain the actual frequency of the generator outlet, that is, the grid frequency f, and perform dead zone judgment on the signal to determine the positive and negative directions of the frequency modulation. If the grid frequency f>50+δ, the energy management system triggers the charging mechanism, and if the grid frequency f<50-δ, the discharging mechanism is triggered.

[0032] If the grid frequency f>50+δ, the actual load Lr of the unit is lower than the set value Ls, and the grid frequency f is greater than the frequency regulation dead zone δ, the unit starts to reduce the load. The trend of the grid frequency f is judged based on the built-in algorithm module of the energy management system:

[0033] 1) The adjustment time is within 20s. The generator set is preferably charged to the energy storage device. It is determined that Δ=|Lr-Ls|≤δ, where δ takes a certain limit value, which is automatically calculated by the system. The DCS load instruction remains unchanged. At this time, the frequency regulation function of the DCS system of the unit is cut off. If the energy storage device does not meet the charging conditions, the DCS system frequency regulation mode is used to reduce the load.

[0034] 2) The adjustment time is between 20s and 60s, mainly based on traditional frequency difference adjustment, and the integrated power is calculated in real time. After 10s, the charging mode of the energy storage device is started for 5s. During this period, the load command is locked, and then the DCS system continues to adjust.

[0035] If the grid frequency f>50+δ, the actual load Lr of the unit is higher than the set value Ls, and the grid frequency f is greater than the dead zone δ, the unit starts to increase the load rapidly; the energy management system evaluates the trend of the grid frequency f:

[0036] 1) If the adjustment time is within 20s, the charging mechanism of the electric energy storage device is triggered, and it is judged that Δ=|Lr-Ls|≤δ, where δ takes a certain limit value, which is automatically calculated by the system. At this time, the original DCS system frequency regulation function of the unit is cut off. If the electric energy storage device does not have the charging conditions, the traditional DCS system frequency regulation method is used to reduce the load, increase the frequency regulation gain, and superimpose the pressure setting value bias (negative value);

[0037] 2) Between 20s and 60s, the frequency difference adjustment is mainly carried out (according to the fixed value compensation), and the charging of the energy storage device is supplemented (according to the slope compensation).

[0038] If the grid frequency f<50-δ, the actual load Lr of the unit is greater than the set value Ls, and the grid frequency f is less than the dead zone δ, the unit starts to increase the load; the energy management system evaluates the trend of the grid frequency f:

[0039] 1) Within 20 seconds, the load is increased by the traditional frequency modulation method of the DCS system (fixed frequency difference compensation) to increase the frequency modulation gain;

[0040] 2) Between 20s and 60s, the real-time load deviation is calculated. At 10s, the wind-solar combined energy storage switch is switched to charge the electric energy storage device. The electric energy storage device quickly compensates the load deviation for 5s. Then, the electric energy storage device performs fixed value compensation (square wave) based on the deviation β between the load command and the expected target command after DCS superimposed compensation.

[0041] If the grid frequency f<50-δ, the actual load Lr of the unit is less than the set value Ls, the grid frequency f is less than the dead zone δ, and the unit quickly increases the load; the energy management system evaluates the trend of the grid frequency f:

[0042] 1) Within 20 seconds, the discharge mechanism of the electric energy storage device is triggered. At this time, the frequency regulation function of the unit DCS system is cut off, and the wind-solar combined energy storage switch is switched to charge the electric energy storage device. If the electric energy storage device does not meet the discharge conditions, the load is increased by the traditional frequency regulation method of the DCS system (fixed frequency difference compensation), the frequency regulation gain is increased, and the pressure setting value bias (positive value) is superimposed;

[0043] 2) Between 20s and 60s, the frequency difference is mainly adjusted (according to the fixed value compensation), and the charging of the energy storage device is supplemented (according to the slope compensation).

[0044] When the grid frequency f exceeds the dead zone, a frequency modulation action is completed, and then the whole process is repeated according to the change of the grid frequency f.

[0045] The wind-solar-storage coordinated frequency regulation optimization control method realizes auxiliary frequency regulation compensation of steam turbine generator sets by building small wind turbines, roof and carport photovoltaics, and integrated electric energy storage in the factory area. The control terminal is connected to the real-time data signals such as the actual power of the generator set and the grid frequency. The probability prediction algorithm is used to evaluate the load increase / decrease space capacity and rate of the generator set and predict the grid frequency. After comprehensive evaluation, for the frequency regulation compensation with probability prediction frequency regulation time less than 20s, "frequency difference compensation" is preferred, and for the frequency regulation compensation less than 60s, "interval electric energy storage compensation" is preferred. Finally, the instantaneous reliable action of the primary frequency regulation of the unit is realized, and the interval stable compensation is used to ensure the stability of the grid frequency. At the same time, the situation of primary frequency regulation being assessed is minimized. Based on the energy management system, the controllable charging of the energy storage device by wind-solar complementarity is realized, and the dependence of the energy storage device on the unit's electric energy is minimized. Green energy storage is preferred, the rapid charging and discharging mechanism of the energy storage system is reduced, and the output is smooth and stable, which effectively increases the utilization hours of the energy storage device. The present invention proposes a flexible adjustment strategy for regionalized load compensation, which can ensure the optimal response of the primary frequency regulation of the coal-fired unit, while reducing the demand for the primary frequency regulation hardware of the unit, performing electricity compensation from the perspective of green energy, making full use of green electricity, and effectively reducing dependence on fossil energy, which is of great significance to achieving carbon emission reduction. Effectively reducing dependence on fossil energy is of great significance to achieving carbon emission reduction.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A wind-solar-storage coordinated frequency modulation optimization control method, characterized in that: The steps include: Step 1: Build a small microgrid system based on small wind turbines, rooftop photovoltaics, and electric energy storage devices, and connect the small microgrid system to the extended analog IO of the DCS system through hard wiring to assist the frequency modulation optimization control of coal-fired units through the synergistic effect of wind, light, and electric energy storage; Step 2: Based on the energy management system, according to the acquired real-time data signals, a probability prediction algorithm is used to evaluate the load space capacity and rate of the generator set and predict the grid frequency for comprehensive evaluation; The real-time data signal refers to the real-time data signal of the actual power of the generator set and the grid frequency; Take the AGC load command Ls, actual power Lr, and grid frequency f, set the sampling period to 1s, extract the PT signal to obtain the actual frequency of the generator outlet, that is, the grid frequency f, and perform dead zone discrimination on the signal to determine the positive and negative direction of the frequency modulation; If the grid frequency f>50+δ, the energy management system triggers the charging mechanism; δ represents the dead zone of frequency regulation action; If the grid frequency f<50-δ, the discharge mechanism is triggered; If the grid frequency f>50+δ, the actual load Lr of the unit is lower than the set value Ls, the unit starts to reduce the load, and the trend of the grid frequency f is judged based on the built-in algorithm module of the energy management system: 1) If the probability prediction frequency regulation time is within 20s, the generator set is used to charge the electric energy storage, and it is judged that Δ=|Lr-Ls|≤Φ, where Φ represents the power deviation and takes a certain limit value, which is obtained by automatic calculation of the system. The DCS load instruction remains unchanged. At this time, the frequency regulation function of the DCS system of the unit is cut off; if the electric energy storage device does not have the charging conditions, the DCS system frequency regulation method is used to reduce the load; 2) The probability prediction frequency adjustment time is between 20s and 60s, mainly based on frequency difference adjustment, and the integrated power is calculated in real time. After 10s, the charging mode of the energy storage device is started for 5s, during which the load command is locked, and then the DCS system continues to adjust; If the grid frequency f>50+δ, the actual load Lr of the unit is higher than the set value Ls, and the unit starts to reduce the load rapidly; the energy management system evaluates the trend of the grid frequency f: 1) If the probability prediction frequency regulation time is within 20s, the charging mechanism of the electric energy storage device is triggered, and it is judged that Δ=|Lr-Ls|≤Φ, where Φ represents the power deviation and takes a certain limit value, which is obtained by automatic calculation of the system. At this time, the frequency regulation function of the unit DCS system is cut off; if the electric energy storage device does not have the charging conditions, the DCS system frequency regulation mode is used to reduce the load, increase the frequency regulation gain, and set the superimposed pressure to a negative value; 2) The probability prediction frequency modulation time is between 20s and 60s, mainly adjusting the frequency difference and supplemented by charging the energy storage device; If the grid frequency f<50-δ, the actual load Lr of the unit is greater than the set value Ls, and the unit starts to increase the load; the energy management system evaluates the trend of the grid frequency f: 1) If the probability prediction frequency modulation time is within 20s, the DCS system frequency modulation method is used to increase the load and increase the frequency modulation gain; 2) The probability prediction frequency regulation time is between 20s and 60s, and the real-time load deviation is calculated. At 10s, the wind-solar combined energy storage switch is switched to charge the electric energy storage device, and the electric energy storage device quickly compensates the load deviation for 5s. Then, the electric energy storage device compensates the frequency difference according to the deviation β between the load command and the expected target command after DCS superimposed compensation; If the grid frequency f<50-δ, the actual load Lr of the unit is less than the set value Ls, and the unit quickly increases the load; the energy management system evaluates the trend of the grid frequency f: 1) The probability prediction frequency regulation time is within 20s, triggering the discharge mechanism of the electric energy storage device. At this time, the frequency regulation function of the unit DCS system is cut off, and the wind-solar combined energy storage switch is switched to charge the electric energy storage device; If the electric energy storage device does not meet the discharge conditions, the DCS system frequency modulation method is used to increase the load, increase the frequency modulation gain, and set the superimposed pressure to a positive value; 2) The probability prediction frequency modulation time is between 20s and 60s, mainly adjusting the frequency difference and supplemented by charging the energy storage device.

2. The wind-solar-storage coordinated frequency modulation optimization control method according to claim 1 is characterized in that: When the grid frequency f exceeds the dead zone, a frequency modulation action is completed, and then the whole process is repeated according to the change of the grid frequency f.

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