CN112018785A - Receiving-end power grid flywheel energy storage frequency modulation method and system based on frequency disturbance complementation - Google Patents

Abstract

The invention provides a method and system for frequency regulation of the power grid _flywheel energy storage frequency at the receiving end based on frequency disturbance complementation, belonging to the technical field of energy storage frequency modulation control of the receiving end power grid. The rated capacity H _FES-N of the energy storage device calculates the required charging capacity H _FES-C of the flywheel energy storage device in real time; according to the frequency fluctuation of the receiving end grid, the real-time computer group needs to change the integral power H _PFC ; according to the frequency disturbance of the receiving end grid , according to the required charging capacity H _FES‑C and the need to change the integral power H _PFC , the flywheel energy storage frequency modulation control is performed. The invention adopts different frequency modulation control modes for the flywheel energy storage device and the unit according to the different frequency disturbances of the power grid, which not only reduces the number of actions of the unit at high frequency, improves the life of the valve and other equipment of the unit, but also can be realized by the flywheel energy storage device. Fast one-time frequency regulation ensures the economical operation of the flywheel energy storage and the integrated frequency regulation system of the unit, and realizes the stable operation of the flywheel energy storage and the integrated frequency regulation system of the unit.

Description

Method and system for frequency regulation of flywheel energy storage in receiving-end power grid based on frequency disturbance complementation

technical field

The invention relates to the technical field of frequency modulation control for energy storage of a receiving end power grid, in particular to a method and a system for frequency modulation of a receiving end power grid flywheel energy storage based on frequency disturbance complementation.

Background technique

Frequency is one of the most important quality indicators in the power grid. For the power grid, the stability of the frequency is achieved by the dynamic balance between the electricity load and the power generation. The change of the system frequency directly reflects the balance of power supply and demand. When the power generation is greater than the load consumption, the system frequency increases, and the load consumption is greater than the power generation, and the system frequency decreases. The power grid frequency must be controlled within an allowable range around 50Hz during operation of the power system, that is, the premise of stable operation of the power system is the real-time balance of power generation and power consumption, otherwise it will cause the power quality of the system to decline, and even lead to system instability in extreme cases. . With a large number of new energy generating units connected to the power grid and the increase of impact loads, in order to ensure the safe and economic operation of the power grid and improve the quality of power consumption of users, the power grid has higher and higher requirements for frequency regulation of units. At present, in China's major regional power grids, large-scale hydropower and thermal power units are the main frequency-modulated power sources, which respond to system frequency changes by continuously adjusting the output of frequency-modulated power sources. However, they each have certain limitations and deficiencies, which affect the frequency of the grid Safety and quality. The problem of insufficient capacity of existing frequency modulation is prominent, and the emergence of new frequency modulation means is urgently needed.

In the event of a UHV transmission line failure, the power supply in the receiving-end power grid needs to be rapidly increased to make up for the frequency drop caused by the power gap. For the grid, the primary frequency control (Primary Frequency Control, PFC) is the key to the grid frequency control. Taking conventional thermal power units as an example, relevant standards such as GB/T 31464 "Grid Operation Guidelines" and GB/T30370 "Guidelines for Primary Frequency Regulation Test and Performance Acceptance of Thermal Power Generator Units" stipulate that the dead zone of units participating in primary frequency regulation should be within the range of ±0.033Hz. . For grid frequency disturbance, after satisfying the effective disturbance conditions, and the frequency exceeds 50.0±0.05Hz and lasts for 1s or more, this disturbance will be defined as a large disturbance, and the maximum continuous evaluation time of the large disturbance is 60s. The effective disturbance that does not meet the standard of large disturbance is defined as small disturbance, and the maximum continuous evaluation time of small disturbance is 30s.

The battery energy storage system has the characteristics of fast response and accurate tracking, making it more efficient than traditional frequency modulation methods. In recent years, the replacement of power plants for frequency regulation by large-scale energy storage systems has attracted the attention of the industry. Compared with traditional power sources, energy storage has obvious technical advantages in providing frequency regulation for power grids, and the economy will gradually appear, which can effectively improve the operating efficiency of the power system. Flywheel Energy Storage (FES) is an advanced physical energy storage technology, which refers to the use of electrical energy to drive the flywheel to rotate at a high speed, convert the electrical energy into mechanical energy, and use the flywheel inertia to drive the motor to generate electricity when needed, and store the stored energy. A form of energy storage in which mechanical energy is converted into electrical output (so-called flywheel discharge). It has the characteristics of high power density, fast response speed, long life, maintenance-free, good scalability, and no pollution. Compared with other types of energy storage methods, such as lithium batteries, lead-acid batteries, pumped storage, etc., the flywheel energy storage power station has the advantages of large output power, fast instantaneous response speed, low long-term operation and maintenance cost, safety and reliability, green environmental protection and no pollution. . In particular, the discharge power response speed of the flywheel energy storage system is fast, reaching the millisecond level, which can meet the requirements of primary frequency modulation control.

State of charge SOC (State of Charge), also known as the remaining power, represents the ratio of the remaining dischargeable power after the energy storage device is used for a period of time or left unused for a long time to the power in the fully charged state, usually expressed as a percentage. It is generally represented by one byte, that is, two-digit hexadecimal (value range is 0 to 100), which means that the remaining energy is 0% to 100%. When SOC=0%, it means that the battery is fully discharged. =100% means the battery is fully charged. For flywheel energy storage control, it is also necessary to monitor its energy state, and adjust it in combination with grid frequency changes and SOC states. For the overall frequency modulation control system, the ideal situation is that the SOC of the energy storage device is 50%, that is, the energy storage device is in the middle position where it can both increase the absorbed energy and decrease the compensation energy, but this brings about the scale of energy storage investment. of increase. For the receiving-end power grid, the large frequency disturbance is generally caused by the sudden drop in the frequency of the power grid caused by the sudden drop of the external power supply, that is, the power supply in the receiving-end power grid needs to perform fast frequency regulation compensation at this time, that is, an energy storage device is required. Perform energy compensation action. At the same time, the small-frequency disturbance generators that appear in the receiving-end power grid can meet the requirements of power grid standards by themselves, that is to say, the flywheel energy storage device can be in a state of full capacity SOC=100%. In addition, when a large frequency disturbance occurs in the power grid, after the flywheel energy storage device releases energy, how to recover to the full capacity state cost-effectively is a practical problem that needs to be studied and realized.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method and system for frequency regulation of flywheel energy storage in the receiving-end power grid based on the complementation of frequency disturbances, which can realize the linkage between the energy storage device and the unit through the complementation of large and small disturbances, and effectively meet the frequency regulation requirements of the power grid, so as to solve the above problems. At least one technical problem exists in the background art.

In order to achieve the above object, the present invention has adopted the following technical solutions:

On the one hand, the present invention provides a method for frequency modulation based on the complementary frequency disturbance of the receiving end power grid flywheel energy storage, the method includes:

When it is judged that the remaining power SOC _FES of the flywheel energy storage device is less than 100%, the required charging capacity H _FES-C of the flywheel energy storage device is calculated in real time in combination with the rated capacity H _FES-N of the flywheel energy storage device;

According to the frequency fluctuation of the receiving end power grid, the real-time computer group needs to change the integral power H _PFC ;

According to the frequency disturbance of the power grid at the receiving end, the flywheel energy storage frequency modulation control is carried out according to the required charging capacity H _FES-C and the need to change the integral power H _PFC .

preferably,

When the frequency of the receiving end grid is not less than the first threshold, the unit needs to reduce the integral power H _PFC ;

When the frequency of the receiving end grid is not greater than the second threshold, the unit needs to increase the integral power H _PFC ;

Wherein, the first threshold is greater than the second threshold;

t₀表示频率超过一次调频动作死区的时刻，t_t表示一次调频计算结束时刻，P₀为机组频率超出死区时机组负荷值，P_t为t时刻机组实际发电有功出力。

t ₀ represents the moment when the frequency exceeds the dead zone of the primary frequency regulation action, t _t represents the end time of the primary frequency regulation calculation, P ₀ is the unit load value when the unit frequency exceeds the dead zone, and P _t is the actual generating power output of the unit at time t.

preferably,

When the frequency of the receiving end grid fluctuates higher than the first threshold, determine the size of the H _FES-C of the flywheel energy storage device and the integral power H _PFC to be reduced by the unit;

If H _FES-C ≥ H _PFC , the unit load remains unchanged, and the integral power H _PFC to be reduced by the unit is charged to the flywheel energy storage device;

If H _FES-C < H _PFC , the unit and the flywheel energy storage device jointly complete the primary frequency modulation, the flywheel energy storage device charges H _FES-C , and the unit reduces the integral power of H _PFC -H _FES-C .

Preferably, when the frequency of the power grid at the receiving end fluctuates below the second threshold, the frequency modulation control of the unit and the flywheel energy storage device is performed according to the type of disturbance.

preferably,

When it is a small disturbance, the unit itself completes the increase of the primary frequency modulation integral power;

When it is a large disturbance, if (H _FES-N -H _FES-C )≥H _PFC , the unit load remains unchanged, and the integral power H _PFC that the unit needs to increase is compensated by the flywheel energy storage device; if (H _FES-N -H _FES-C )<H _PFC , the primary frequency modulation is completed by the unit and the flywheel energy storage device, the flywheel energy storage device discharges H _FED-N -H _FES-C , and the unit adds H _PFC -(H _FES-N - H _FES-C ) integrated power.

Preferably, the calculated charging capacity is:

H _FES-C =(100%-SOC _FES )×H _FES-N .

Preferably, the first threshold is 50.033 Hz, and the second threshold is 49.967 Hz.

In a second aspect, the present invention also provides a receiving-end power grid flywheel energy storage frequency modulation system based on frequency disturbance complementation, the system comprising:

The first calculation module is used to calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time in combination with the rated capacity H _FES-N of the flywheel energy storage device when the remaining power SOC _FES of the flywheel energy storage device is less than 100%;

The second calculation module is used for according to the frequency fluctuation of the receiving end power grid, the real-time computer group needs to change the integral power H _PFC ;

The frequency modulation control module is used for frequency modulation control of flywheel energy storage according to the frequency disturbance of the receiving end power grid, according to the required charging capacity H _FES-C and the need to change the integral power H _PFC .

preferably,

The first calculation module includes a first judgment unit and a chargeable capacity calculation unit;

The first judgment unit is used to judge whether the remaining power SOC _FES of the flywheel energy storage device is less than 100%, and when it is judged that the remaining power SOC _FES of the flywheel energy storage device is less than 100%, the remaining power SOC _FES of the flywheel energy storage device is determined. Send to the charging capacity calculation unit;

The required charging capacity calculation unit is configured to calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time in combination with the rated capacity H _FES-N and the remaining power SOC _FES of the flywheel energy storage device.

preferably,

The second calculation module includes a second judgment unit, and the second judgment unit is used for judging the frequency fluctuation range of the receiving-end power grid;

When the frequency of the receiving end grid is not less than the first threshold, the unit needs to reduce the integral power _HPFC ; when the frequency of the receiving end grid is not greater than the second threshold, the unit needs to increase the integral power _HPFC .

preferably,

The frequency modulation control module includes a third judgment unit and a control unit;

The third judging unit is used for judging the size of the H _FES-C of the flywheel energy storage device and the integral power H _PFC to be reduced by the unit when the frequency of the receiving end grid fluctuates higher than the first threshold;

The control unit is used to control the integral power H _PFC to be reduced by the unit to charge the flywheel energy storage device when H FES- _C ≥ H _PFC ; when H _FES-C < H _PFC , control the flywheel energy storage device to charge H _FES-C , the unit reduces the integral power of _HPFC -H _FES-C .

preferably,

The frequency regulation control module further includes a fourth determination unit, configured to determine the type of frequency disturbance of the receiving-end power grid when the frequency of the receiving-end power grid fluctuates lower than the second threshold.

preferably,

The control unit is further configured to, when the frequency disturbance type of the receiving end power grid is a small disturbance, control the unit itself to complete the increase of the primary frequency modulation integral electric quantity.

preferably,

The frequency regulation control module further includes a fifth judgment unit for judging the difference between the rated capacity and the capacity to be charged and the size of the integral power to be changed when the frequency disturbance type of the receiving end power grid is a small disturbance.

preferably,

The control unit is also used to, when (H _FES-N- H _FES-C )≥H _PFC , control the flywheel energy storage device to compensate the integral power H _PFC that the unit needs to increase; when (H _FES-N- H _FES- When _C )<H _PFC , the flywheel energy storage device is controlled to discharge H _FED-N -H _FES-C , and the unit increases the integral power of H _PFC -(H _FES-N -H _FES-C ).

In a third aspect, the present invention also provides a computer device comprising a memory and a processor, the processor and the memory communicate with each other, the memory stores program instructions executable by the processor, the processor The program instructions are invoked to execute the method as described above.

In a fourth aspect, the present invention also provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, implements the above-mentioned method.

The beneficial effects of the invention are as follows: according to the different frequency disturbances of the power grid, different frequency modulation control modes are adopted for the flywheel energy storage device and the unit, which not only reduces the number of operations of the unit at high frequency, improves the life of the unit valve and other equipment, but also can store the energy through the flywheel. The device can realize fast one-time frequency regulation, ensure the economical operation of the flywheel energy storage and the integrated frequency regulation system of the unit, and realize the stable operation of the flywheel energy storage and the integrated frequency regulation system of the unit.

Additional aspects and advantages of the present invention will be set forth in part in the following description, which will be apparent from the following description, or may be learned by practice of the present invention.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic block diagram of the flywheel energy storage frequency modulation system based on frequency disturbance complementation at the receiving end according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart of the method for frequency modulation of the flywheel energy storage in the receiving-end power grid based on the complementary frequency disturbance according to Embodiment 2 of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below through the accompanying drawings are exemplary and are only used to explain the present invention, but not to be construed as a limitation of the present invention.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should also be understood that terms such as those defined in the general dictionary should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as herein, are not to be taken in an idealized or overly formal sense. explain.

It will be understood by those skilled in the art that the singular forms "a", "an", "the" and "the" as used herein can include the plural forms as well, unless expressly stated otherwise. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of stated features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements and/or groups thereof.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

In order to facilitate the understanding of the present invention, the present invention will be further explained and described below with reference to the accompanying drawings with specific embodiments, and the specific embodiments do not constitute limitations to the embodiments of the present invention.

Those skilled in the art should understand that the accompanying drawings are only schematic diagrams of the embodiments, and the components in the accompanying drawings are not necessarily necessary to implement the present invention.

Example 1

As shown in FIG. 1 , Embodiment 1 of the present invention provides a receiving-end power grid flywheel energy storage and frequency regulation system based on frequency disturbance complementation, and the system includes:

The first calculation module is used to calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time in combination with the rated capacity H _FES-N of the flywheel energy storage device when the remaining power SOC _FES of the flywheel energy storage device is less than 100%.

The second calculation module is used for the real-time computer group to change the integral power H _PFC according to the frequency fluctuation of the receiving end power grid.

The frequency modulation control module is used for frequency modulation control of flywheel energy storage according to the frequency disturbance of the receiving end power grid, according to the required charging capacity H _FES-C and the need to change the integral power H _PFC .

In this embodiment 1, the first calculation module includes a first judgment unit and a chargeable capacity calculation unit.

The first judging unit is used to judge whether the remaining power SOC _FES of the flywheel energy storage device is less than 100%, and when it is judged that the remaining power SOC _FES of the flywheel energy storage device is less than 100%, send the remaining power SOC _FES of the flywheel energy storage device. Calculating unit for required charging capacity.

The required charging capacity calculation unit is configured to calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time in combination with the rated capacity H _FES-N and the remaining power SOC _FES of the flywheel energy storage device.

In this embodiment 1, the second calculation module includes a second judgment unit, and the second judgment unit is used for judging the frequency fluctuation range of the receiving-end power grid;

When the frequency of the receiving end grid is not less than the first threshold, the unit needs to reduce the integral power _HPFC ; when the frequency of the receiving end grid is not greater than the second threshold, the unit needs to increase the integral power _HPFC .

In this embodiment 1, the frequency modulation control module includes a third judgment unit and a control unit.

The third judging unit is used for judging the size of the _HFES-C of the flywheel energy storage device and the integral power H _PFC to be reduced by the unit when the frequency of the receiving end grid fluctuates higher than the first threshold.

The control unit is used to control the integral power H _PFC to be reduced by the unit to charge the flywheel energy storage device when H FES- _C ≥ H _PFC ; when H _FES-C < H _PFC , control the flywheel energy storage device to charge H PFC _FES-C , the unit reduces the integral power of _HPFC -H _FES-C .

In Embodiment 1, the frequency regulation control module further includes a fourth determination unit, configured to determine the type of frequency disturbance of the receiving-end power grid when the frequency of the receiving-end power grid fluctuates lower than the second threshold.

In this embodiment 1, when the fourth judgment unit judges that the frequency disturbance of the receiving end power grid is a small disturbance, the control unit controls the unit itself to complete the increase of the primary frequency modulation integral power. When the fourth judging unit judges that the frequency disturbance of the power grid at the receiving end is a large disturbance, the fifth judging unit judges the size of (H _FES-N -H _FES-C ) and H _PFC , if (H _FES-N -H _{FES-C )} )≥H _PFC , the control unit controls the flywheel energy storage device to compensate the integral power H _PFC that the unit needs to increase; if (H _FES-N -H _FES-C )<H _PFC , the control unit controls the flywheel energy storage device to discharge H _FED-N -H _FES-C , the unit increases the integral power of _HPFC -(H _FES-N -H _FES-C ).

In the present embodiment 1, the control method process for frequency modulation using the above-mentioned system is:

When the first judgment unit judges that the remaining power SOC _FES of the flywheel energy storage device is less than 100%, the required charging capacity calculation unit combines the rated capacity H _FES-N of the flywheel energy storage device to calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time. . The required charging capacity is: H _FES-C =(100%-SOC _FES )×H _FES-N .

t₀表示频率超过一次调频动作死区的时刻，t_t表示一次调频计算结束时刻，P₀为机组频率超出死区时机组负荷值，P_t为t时刻机组实际发电有功出力。其中，第一阈值大于第二阈值。The second judging unit judges that the frequency of the receiving end power grid fluctuates when the frequency of the receiving end power grid is not less than the first threshold, the unit needs to reduce the integral power H _PFC ; when the second judgment unit judges that the frequency of the receiving end power grid is not greater than the second threshold, the unit needs to Increase the integral power H _PFC .

t ₀ represents the moment when the frequency exceeds the dead zone of the primary frequency regulation action, t _t represents the end time of the primary frequency regulation calculation, P ₀ is the unit load value when the unit frequency exceeds the dead zone, and P _t is the actual generating power output of the unit at time t. Wherein, the first threshold is greater than the second threshold.

According to the frequency disturbance of the power grid at the receiving end, the flywheel energy storage frequency modulation control is carried out according to the required charging capacity H _FES-C and the need to change the integral power H _PFC .

When the frequency of the receiving end grid fluctuates not lower than the first threshold, the third judgment unit judges the _HFES-C of the flywheel energy storage device and the size of the integral power H _PFC to be reduced by the unit. If H _FES-C ≥ H _PFC , the load of the unit remains unchanged, and the control unit controls to charge the integral power H _PFC to be reduced by the unit to the flywheel energy storage device; if H _FES-C < H _PFC , the unit and the flywheel energy storage device are charged To complete the primary frequency regulation together, the control unit controls the flywheel energy storage device to charge the H _FES-C , and the unit reduces the integral power of the H _PFC -H _FES-C .

When the frequency of the receiving-end power grid fluctuates lower than the second threshold, the fourth judgment unit judges the type of the frequency disturbance of the receiving-end power grid. When the fourth judgment unit judges that the frequency disturbance of the power grid at the receiving end is a small disturbance, the control unit controls the unit itself to complete the increase of the primary frequency modulation integral power. When the fourth judging unit judges that the frequency disturbance of the power grid at the receiving end is a large disturbance, the fifth judging unit judges the size of (H _FES-N -H _FES-C ) and H _PFC , if (H _FES-N -H _{FES-C )} )≥H _PFC , the control unit controls the flywheel energy storage device to compensate the integral power H _PFC that the unit needs to increase; if (H _FES-N -H _FES-C )<H _PFC , the control unit controls the flywheel energy storage device to discharge H _FED-N -H _FES-C , the unit increases the integral power of _HPFC -(H _FES-N -H _FES-C ).

Example 2

As shown in FIG. 2 , Embodiment 2 of the present invention provides a frequency-disturbance complementary control method for receiving-end power grid flywheel energy storage frequency regulation, which combines the power grid frequency disturbance with the energy management of the flywheel energy storage device to reasonably allocate energy distribution. Ensure the safe, economical and stable operation of the flywheel energy storage and the integrated frequency regulation system of the unit.

As can be seen from Figure 1, the method in this embodiment 2 includes the following processes:

S1: Monitor whether the SOC _FES of the flywheel energy storage device is less than 100% by the first judgment unit.

S2: When the SOC _FES of the flywheel energy storage device monitored by the first judgment unit is less than 100%, the required charging capacity calculation unit calculates the required charging capacity of the flywheel energy storage device in real time according to the rated capacity H _FES-N and SOC _FES of the flywheel energy storage device H _FES-C .

S3: The second judgment unit monitors the frequency fluctuation of the power grid, and calculates the integral power H _PFC-D that needs to be reduced or the integral power H _PFC-I that needs to be increased when the frequency disturbance of the group is real-time.

S4: According to the different frequency disturbance of the power grid, combined with _HFES-C , _HPFC-I , _HPFC-D , etc., the flywheel energy storage and the integrated frequency regulation control of the unit are carried out.

In step S2, the required charging capacity of the flywheel energy storage device: H _FES-C =(100%-SOC _FES )×H _FES-N .

积分电量；第二判断单元判断的电网频率f<49.967Hz时，机组需增加

积分电量。其中，t₀为频率超过一次调频动作死区的时刻，t_t为一次调频计算结束时刻，P₀为机组频率超出死区时机组负荷值，P_t为t时刻机组实际发电有功出力。The primary frequency modulation load compensation value of thermal power units must meet the requirements of relevant technical standards such as GB/T30370 "Guidelines for Primary Frequency Modulation Test and Performance Acceptance of Thermal Power Generation Units", Q/GDW 669 "Guidelines for Primary Frequency Modulation Tests of Thermal Power Generation Units", and the unit participates once The frequency modulation dead zone f _D should be within ±0.033Hz, so in step S3, when the grid frequency f ≥ 50.033Hz judged by the second judgment unit, the unit needs to reduce

Integral power; when the grid frequency f<49.967Hz judged by the second judgment unit, the unit needs to increase

Integral power. Among them, t ₀ is the time when the frequency exceeds the dead zone of the primary frequency regulation action, t _t is the end time of the primary frequency regulation calculation, P ₀ is the unit load value when the unit frequency exceeds the dead zone, and P _t is the actual generating power of the unit at time t.

In step S4, when the grid frequency is disturbed not lower than 50.033Hz, the third judgment unit judges whether the H _FES-C of the flywheel energy storage device is greater than the H _PFC-D of the unit: if H _FES-C ≥ H _PFC-D , the unit load remains unchanged, and the control unit charges the integral power H _PFC-D that the unit needs to reduce to the flywheel energy storage device; if H _FES-C < H _PFC-D , the unit and the flywheel energy storage device jointly complete this time Frequency modulation, the control unit controls the flywheel energy storage device to charge the H _FES-C , and the unit reduces the H _PFC-D -H _FES-C integral power.

In step S4, when the grid frequency has a disturbance lower than 49.967 Hz, the fourth determination unit determines the disturbance type. When the disturbance type is small disturbance, the unit itself completes the increase of the primary frequency modulation integral power; when the disturbance type is large disturbance, the fifth judgment unit judges (H _FES-N -H _FES-C ) and H _PFC-I size relationship. If (H _FES-N -H _FES-C )≥H _PFC-I , the unit load remains unchanged, and the control unit compensates the integral power H _PFC-I that the unit needs to increase by the flywheel energy storage device; if (H _FES-N -H _FES-C )<H _PFC-I , the primary frequency modulation is completed by the unit and the flywheel energy storage device together, the control terminal element controls the flywheel energy storage device to discharge H _FED-N -H _FES-C , the unit increases H _{PFC- I} -(H _FES-N -H _FES-C ) integral power.

In this embodiment 2, an example of the application of the above method in an actual power grid is further described by taking the combined frequency modulation of the flywheel energy storage and the unit in a provincial power grid in a power grid area as an example.

The effective disturbance is defined as the frequency that exceeds the primary frequency modulation dead zone (50±0.033Hz) and lasts for 6 seconds or more, while the maximum frequency deviation reaches 50±0.038Hz. After satisfying the effective disturbance conditions, and the frequency exceeds 50.0±0.05Hz and lasts for 1s or more, this disturbance will be defined as a large disturbance, and the maximum continuous evaluation time of the large disturbance is 60s. The effective disturbance that does not meet the standard of large disturbance is defined as small disturbance, and the maximum continuous evaluation time of small disturbance is 30s.

There is a 1000MW ultra-supercritical secondary reheat unit in a power plant in a provincial power grid. At present, the ultra-supercritical secondary reheat unit has the characteristics of high parameters, low energy consumption and more environmental protection. The power of the high-pressure cylinder of the steam turbine of the secondary reheat unit is nearly half lower than that of the primary reheat unit. This feature reduces the throttling loss of the steam turbine to a certain extent and improves the operation efficiency of the steam turbine, but at the same time, it also causes the steam turbine to quickly change the load capacity is poor. It can be seen from the data of a frequency regulation test that after the first frequency regulation action, the load response in the first 15 seconds is not enough, mainly because under the same gate action range, the power of the secondary reheat unit due to the ultra-high pressure cylinder involved in regulation is relatively conventional. The unit is greatly reduced, and the load increase of the unit in a short time cannot meet the requirements of primary frequency regulation. Therefore, the unit is equipped with a flywheel energy storage device to jointly realize the primary frequency modulation function. Considering the economy, the design rated capacity of the flywheel energy storage device is 6MW, which can last for 60s. The flywheel can be charged at any time when the speed is lower than 100% of the rated speed. The output power rise time of the flywheel energy storage device is less than 2ms, and the response delay is less than 5ms.

At a certain time, the SOC _FES of the flywheel energy storage device is 85%. Since the rated capacity P _FES-N = 6MW for 60s, then

H _FES-N =6×60=360MWs,

H _FES-C =(100%-SOC _FES )×H _FES-N =15%×360=54MWs.

The grid frequency fluctuates at the next moment, the frequency is 50.042Hz, and the duration is 8s, which meets the assessment conditions for small grid frequency disturbance, and the load that needs to be reduced for the frequency disturbance of the computer group

Since if H _FES-C > H _PFC-D , the load of the unit remains unchanged at this time, and the integral power H _PFC-D to be reduced by the unit is charged to the flywheel energy storage device, that is, the flywheel energy storage device absorbs 10.8MWs from the power grid in the plant This time, the unit does not need to control and adjust the air, coal, and water. On the one hand, it reduces the life of the unit equipment, and at the same time improves the working efficiency of the unit, and avoids short-term transient fluctuations. Energy consumption caused by insufficient combustion.

Example 3

Embodiment 3 of the present invention provides a computer device, including a memory and a processor, the processor and the memory communicate with each other, the memory stores program instructions that can be executed by the processor, and the processor calls the The program instruction executes a frequency regulation control method for the flywheel energy storage of the receiving end grid based on frequency disturbance complementation, and the method includes:

S1: Monitor whether the SOC _FES of the flywheel energy storage device is less than 100%;

S2: According to the rated capacity H _FES-N and SOC _FES of the flywheel energy storage device, calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time;

S3: monitor the frequency fluctuation of the power grid, the real-time computer group frequency disturbance needs to reduce the integral power H _PFC-D or the need to increase the integral power H _PFC-I ;

S4: According to the different frequency disturbance of the power grid, combined with _HFES-C , _HPFC-I , _HPFC-D , etc., the flywheel energy storage and the integrated frequency regulation control of the unit are carried out.

Example 4

Embodiment 4 of the present invention provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, implements a frequency-disturbance-complementary-based receiving-end power grid flywheel energy storage frequency modulation control method, and the method includes:

S1: Monitor whether the SOC _FES of the flywheel energy storage device is less than 100%;

S2: According to the rated capacity H _FES-N and SOC _FES of the flywheel energy storage device, calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time;

S3: monitor the frequency fluctuation of the power grid, the real-time computer group frequency disturbance needs to reduce the integral power H _PFC-D or the need to increase the integral power H _PFC-I ;

S4: According to the different frequency disturbance of the power grid, combined with _HFES-C , _HPFC-I , _HPFC-D , etc., the flywheel energy storage and the integrated frequency regulation control of the unit are carried out.

To sum up, the system and method for frequency modulation based on the complementary frequency disturbance of the receiving end power grid flywheel energy storage according to the embodiment of the present invention, through the monitored changes in the state of charge of the flywheel energy storage device and the frequency of the power grid, organically The flywheel is combined with the frequency modulation of the unit, and different frequency modulation control methods are adopted according to the different frequency disturbances, which effectively ensures the economical operation of the flywheel energy storage and the integrated frequency modulation system of the unit; the high frequency small disturbance of the unit is used to compensate the needs of the flywheel energy storage device. The charging capacity not only reduces the number of actions of the unit at high frequency, and improves the life of the unit's valves and other equipment, but also realizes a fast one-time frequency regulation through the flywheel energy storage device, realizing the stable operation of the flywheel energy storage and the integrated frequency regulation system of the unit.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included within the protection scope of the present disclosure.

Although the specific embodiments of the present disclosure have been described above in conjunction with the accompanying drawings, they do not limit the protection scope of the present disclosure. Those skilled in the art should understand that on the basis of the technical solutions disclosed in the present invention, those skilled in the art do not need to pay Various modifications or deformations that can be made by creative work shall be covered within the protection scope of the present invention.

Claims (17)

1. a method for frequency modulation based on the receiving end grid flywheel energy storage frequency disturbance complementary, it is characterized in that: When it is judged that the remaining power SOC _FES of the flywheel energy storage device is less than 100%, the required charging capacity H _FES-C of the flywheel energy storage device is calculated in real time in combination with the rated capacity H _FES-N of the flywheel energy storage device; According to the frequency fluctuation of the receiving end power grid, the real-time computer group needs to change the integral power H _PFC ; According to the frequency disturbance of the power grid at the receiving end, the flywheel energy storage frequency modulation control is carried out in combination with the required charging capacity H _FES-C and the need to change the integral power H _PFC . 2. the receiving end power grid flywheel energy storage frequency modulation method based on frequency disturbance complementary according to claim 1, is characterized in that: When the frequency of the receiving end grid is not less than the first threshold, the unit needs to reduce the integral power H _PFC ; When the frequency of the receiving end grid is not greater than the second threshold, the unit needs to increase the integral power H _PFC ; Wherein, the first threshold is greater than the second threshold;

t ₀ represents the moment when the frequency exceeds the dead zone of the primary frequency regulation action, t _t represents the end time of the primary frequency regulation calculation, P ₀ is the unit load value when the unit frequency exceeds the dead zone, and P _t is the actual generating power output of the unit at time t. 3. the receiving end power grid flywheel energy storage frequency modulation method based on frequency disturbance complementary according to claim 2, is characterized in that: When the frequency of the receiving end grid fluctuates higher than the first threshold, determine the size of the H _FES-C of the flywheel energy storage device and the integral power H _PFC to be reduced by the unit; If H _FES-C ≥ H _PFC , the unit load remains unchanged, and the integral power H _PFC to be reduced by the unit is charged to the flywheel energy storage device; If H _FES-C < H _PFC , the unit and the flywheel energy storage device jointly complete the primary frequency modulation, the flywheel energy storage device charges H _FES-C , and the unit reduces the integral power of H _PFC -H _FES-C . 4. the receiving end power grid flywheel energy storage frequency modulation method based on frequency disturbance complementary according to claim 2, is characterized in that: When the frequency of the receiving end grid fluctuates below the second threshold, the frequency regulation control of the unit and the flywheel energy storage device is performed according to the type of disturbance. 5. the receiving-end power grid flywheel energy storage frequency modulation method based on frequency disturbance complementary according to claim 4, is characterized in that: When it is a small disturbance, the unit itself completes the increase of the primary frequency modulation integral power; When it is a large disturbance, if (H _FES-N -H _FES-C )≥H _PFC , the unit load remains unchanged, and the integral power H _PFC that the unit needs to increase is compensated by the flywheel energy storage device; if (H _FES-N -H _FES-C )<H _PFC , the primary frequency modulation is completed by the unit and the flywheel energy storage device, the flywheel energy storage device discharges H _FED-N -H _FES-C , and the unit adds H _PFC -(H _FES-N - H _FES-C ) integrated power. 6. The receiving-end grid flywheel energy storage frequency modulation method based on frequency disturbance complementation according to any one of claims 1-5, is characterized in that, calculating the required charging capacity is: H _FES-C =(100%-SOC _FES )×H _FES-N . 7. The receiving-end grid flywheel energy storage frequency regulation method based on the complementary frequency disturbance according to any one of claims 2-5, it is characterized in that: The first threshold is 50.033 Hz, and the second threshold is 49.967 Hz. 8. A receiving-end power grid flywheel energy storage frequency regulation system based on frequency disturbance complementation, is characterized in that, comprises: The first calculation module is used to calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time in combination with the rated capacity H _FES-N of the flywheel energy storage device when the remaining power SOC _FES of the flywheel energy storage device is less than 100%; The second calculation module is used for according to the frequency fluctuation of the receiving end power grid, the real-time computer group needs to change the integral power H _PFC ; The frequency modulation control module is used for frequency modulation control of flywheel energy storage according to the frequency disturbance of the receiving end power grid, according to the required charging capacity H _FES-C and the need to change the integral power H _PFC . 9. The receiving-end power grid flywheel energy storage frequency modulation system based on frequency disturbance complementation according to claim 8, is characterized in that: The first calculation module includes a first judgment unit and a chargeable capacity calculation unit; The first judgment unit is used to judge whether the remaining power SOC _FES of the flywheel energy storage device is less than 100%, and when it is judged that the remaining power SOC _FES of the flywheel energy storage device is less than 100%, the remaining power SOC _FES of the flywheel energy storage device is determined. Send to the charging capacity calculation unit; The required charging capacity calculation unit is configured to calculate the required charging capacity H _FES-C of the flywheel energy storage device in real time in combination with the rated capacity H _FES-N and the remaining power SOC _FES of the flywheel energy storage device. 10. The receiving-end power grid flywheel energy storage frequency modulation system based on frequency disturbance complementation according to claim 8, is characterized in that: The second calculation module includes a second judgment unit, and the second judgment unit is used for judging the frequency fluctuation range of the receiving-end power grid; When the frequency of the receiving end grid is not less than the first threshold, the unit needs to reduce the integral power _HPFC ; when the frequency of the receiving end grid is not greater than the second threshold, the unit needs to increase the integral power _HPFC . 11. The receiving-end power grid flywheel energy storage frequency modulation system based on frequency disturbance complementation according to claim 10, is characterized in that: The frequency modulation control module includes a third judgment unit and a control unit; The third judging unit is used for judging the size of the H _FES-C of the flywheel energy storage device and the integral power H _PFC to be reduced by the unit when the frequency of the receiving end grid fluctuates higher than the first threshold; The control unit is used to control the integral power H _PFC to be reduced by the unit to charge the flywheel energy storage device when H FES- _C ≥ H _PFC ; when H _FES-C < H _PFC , control the flywheel energy storage device to charge H _FES-C , the unit reduces the integral power of _HPFC -H _FES-C . 12. The receiving-end power grid flywheel energy storage and frequency regulation system based on frequency disturbance complementation according to claim 11, wherein: The frequency regulation control module further includes a fourth determination unit, configured to determine the type of frequency disturbance of the receiving-end power grid when the frequency of the receiving-end power grid fluctuates lower than the second threshold. 13. The receiving-end power grid flywheel energy storage and frequency regulation system based on frequency disturbance complementarity according to claim 12, characterized in that: The control unit is further configured to, when the frequency disturbance type of the receiving end power grid is a small disturbance, control the unit itself to complete the increase of the primary frequency modulation integral electric quantity. 14. The receiving-end power grid flywheel energy storage frequency regulation system based on frequency disturbance complementation according to claim 13, wherein: The frequency regulation control module further includes a fifth judgment unit for judging the difference between the rated capacity and the capacity to be charged and the size of the integral power to be changed when the frequency disturbance type of the receiving end power grid is a small disturbance. 15. The receiving-end power grid flywheel energy storage and frequency regulation system based on frequency disturbance complementation according to claim 14, characterized in that: The control unit is also used to, when (H _FES-N- H _FES-C )≥H _PFC , control the flywheel energy storage device to compensate the integral power H _PFC that the unit needs to increase; when (H _FES-N- H _FES- When _C )<H _PFC , the flywheel energy storage device is controlled to discharge H _FED-N -H _FES-C , and the unit increases the integral power of H _PFC -(H _FES-N -H _FES-C ). 16. A computer device, comprising a memory and a processor, wherein the processor and the memory communicate with each other, and the memory stores program instructions executable by the processor, wherein the processor calls the The program instructions perform the method of any one of claims 1-7. 17. A computer-readable storage medium storing a computer program, wherein the method according to any one of claims 1-7 is implemented when the computer program is executed by a processor.

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