CN115864447B - Frequency control method and system for photovoltaic energy storage hybrid system - Google Patents
Frequency control method and system for photovoltaic energy storage hybrid system Download PDFInfo
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Abstract
The invention belongs to the technical field of energy system control, and relates to a frequency control method and a frequency control system of a photovoltaic energy storage hybrid system, wherein the method divides the frequency supporting process of an alternating current power grid after active disturbance into two stages of transient frequency supporting and quasi-steady frequency supporting; the transient frequency support stage adopts a frequency emergency control strategy; the quasi-steady frequency support stage adopts a frequency stability control strategy, and the frequency stability control strategy is realized by a stable frequency judgment controller and a frequency correction controller; aiming at different phases of the frequency response of the alternating current power grid after active disturbance, the invention provides two control strategies of transient frequency support and quasi-steady state frequency support, and realizes the whole process support of the photovoltaic energy storage hybrid system on the frequency of the alternating current power grid.
Description
Technical Field
The invention belongs to the technical field of energy system control, and particularly relates to a frequency control method and system of a photovoltaic energy storage hybrid system.
Background
The new energy power generation is accelerated to replace the traditional fossil energy power generation, and the construction of a novel power system becomes a great trend of power system development. Solar energy is widely used as a low-carbon sustainable inexhaustible green energy source. However, due to the output characteristics of the photovoltaic system, the frequency response performance of the photovoltaic generator set is not ideal, the photovoltaic generator set does not have the capability of carrying out inertia response and primary frequency modulation along with the change of the frequency of the power grid, and when the photovoltaic system is subjected to active disturbance, the photovoltaic generator set cannot form effective support for the frequency of the power grid. The energy storage system has the advantages of quick response characteristic, accurate instruction tracking characteristic and the like, and the energy storage system is utilized to assist the photovoltaic system in building the photovoltaic energy storage hybrid system, so that the frequency supporting capacity of the photovoltaic generator set can be effectively improved, photovoltaic power generation fluctuation is stabilized, and the safety and stability of the frequency of the photovoltaic system are further guaranteed.
Due to the characteristics of the energy storage system, the existing frequency control strategy for improving the frequency response performance of the photovoltaic generator set by using the energy storage system can only provide short-term frequency support, and cannot continuously play a role in frequency support in the whole frequency response process from the occurrence of active disturbance until the frequency is restored to the reference value. Increasing the capacity of the energy storage system helps to solve such problems, but also significantly increases the investment cost of the photovoltaic energy storage hybrid system and reduces the economics of the operation of the photovoltaic energy storage hybrid system. Therefore, it is necessary to study how to improve the frequency supporting capability of the photovoltaic power generating unit to the photovoltaic energy storage hybrid system on the basis of comprehensively considering the frequency response performance and the operation economy, and the problem to be solved is urgent.
Disclosure of Invention
The invention aims to provide a frequency control method and a frequency control system for a photovoltaic energy storage hybrid system, which are capable of considering frequency response performance and operation economy. The invention can realize the power adjustment of the whole process of the frequency of the alternating current power grid after the active disturbance, improve the lowest point of the frequency of the alternating current power grid after the active disturbance, and effectively improve the frequency supporting capacity of the alternating current power grid of the photovoltaic generator set.
A frequency control method of a photovoltaic energy storage hybrid system divides the frequency supporting process of an alternating current power grid after active disturbance into two stages of transient frequency supporting and quasi-steady frequency supporting;
the transient frequency support stage adopts a frequency emergency control strategy: in a normal running state, the photovoltaic energy storage hybrid system continuously monitors the real-time frequency f of the alternating current power grid; when disturbance occurs in the alternating current power grid and the frequency deviation delta f exceeds a set range, the frequency emergency control function generates a control signal to the energy storage, the energy storage is required to be controlled proportionally, the power is increased according to the frequency deviation delta f, and the coefficient of the proportional control is the frequency emergency control coefficient k r The power of the increased power is k r XΔf, the increased power is denoted as P sp The method comprises the steps of carrying out a first treatment on the surface of the In the process, the energy storage releases the stored energy according to the control signal to provide energy support; furthermore, the frequency emergency control coefficient k r Dynamically changing during control, frequency emergency control coefficient k r In direct proportion to the frequency change rate f 'of the alternating current power grid, when the value of the frequency change rate f' of the alternating current power grid is overlarge, the frequency emergency control coefficient k is formed r The value of which exceeds the maximum frequency emergency control coefficient k r-max When k is r Let k be r-max The method comprises the steps of carrying out a first treatment on the surface of the Comparing the alternating current power grid frequency change rate f' with the reference frequency change rate f set by the photovoltaic energy storage hybrid system and used for exiting frequency emergency control set 'and counting by a counter, when the frequency change rate f' of the continuous five times alternating current power grid is smaller than the reference frequency change rate f set by the photovoltaic energy storage hybrid system and exiting the frequency emergency control set ' when the energy storage enable holding module maintains the current power output as P sp No additional frequency emergency support is provided, and the frequency emergency control is exited;
the quasi-steady frequency support stage adopts a frequency stability control strategy, and the frequency stability control strategy is realized by a stable frequency judgment controller and a frequency correction controller; judging whether the frequency emergency control is finished or not by the stable frequency judging controller; the stable frequency judging controller monitors whether the absolute value of the frequency change rate of the alternating current power grid is smaller than a preset value, if so, the stable frequency judging controller outputs a signal, the frequency correction controller is started, and otherwise, the frequency correction controller is not started;
the frequency correction controller monitors whether the frequency of the stabilized alternating current power grid can be within a safe range; if the stabilized AC network frequency is within the safe range, the frequency correction controller is not started, and if the stabilized AC network frequency is not within the safe range, the frequency correction controller is started, and at the moment, the energy storage starts to be carried out at a rated rate k s-max And (3) increasing the power output to the alternating current power grid until the frequency of the alternating current power grid enters a safe range, and stopping increasing the output power by the energy storage and maintaining the power.
Further preferably, in the process of continuously outputting the stored energy, whether the frequency of the alternating current power grid enters a safety range is monitored in real time, and a frequency margin is set, wherein the frequency margin ensures that the frequency of the alternating current power grid can maintain a continuously rising state and finally is stabilized in the safety range when the frequency of the alternating current power grid exceeds the lower limit of the safety range for the first time in the process of supporting the stored energy, so that the frequency of the alternating current power grid is ensured to be continuously stabilized.
Further preferably, the total revenue of the photovoltaic energy storage hybrid system is expressed as:
b is the total income of the photovoltaic energy storage hybrid system, B ct To keep service revenue for spinning reserve, B f To provide revenue for FM services, B ct.pen Deficiency for rotating reserve of actual capacity not meeting system requirements, B f.pen Deficit to provide frequency response compensation, C is contract capacity to provide spinning reserve, C rt1 、C rt2 The capacity of primary frequency modulation and secondary frequency modulation respectively, p is the reserve price of rotation, p f1 、p f2 Respectively is one-time adjustmentPrice per unit capacity, k, of frequency-modulated services ct To penalty coefficients for rotational redundancy that do not meet system requirements, p LBMP The marginal electricity price of the node;
capacity C of photovoltaic energy storage hybrid system for primary frequency modulation and secondary frequency modulation rt1 、C rt2 Respectively with the maximum frequency emergency control coefficient k of the stored energy r-max Rated rate k s-max A positive correlation exists between the two;
wherein m is 1 、m 2 Respectively, correlation coefficients, and delta P is obtained through off-line simulation D The maximum expected disturbance of the alternating current power grid; in the rotation reserve clearing price p, primary frequency modulation and secondary frequency modulation service unit capacity price p f1 、p f2 Dynamically adjusting the maximum frequency emergency control coefficient k of the stored energy by calculating the total revenue B of the expected photovoltaic stored energy hybrid system under expected disturbance under the condition of fluctuation r-max Rated rate k s-max The primary and secondary frequency modulation control parameters for maximizing the operation economy of the photovoltaic energy storage hybrid system are obtained, namely:
。
the invention also provides a frequency control system of the photovoltaic energy storage hybrid system, which comprises,
the monitoring device is used for continuously monitoring the real-time frequency of the alternating current power grid in the photovoltaic energy storage hybrid system;
a proportional controller for requiring proportional control of the stored energy and increasing the power of the transmission according to the amount of frequency deviation;
the comparator is used for comparing the frequency change rate of the alternating current power grid with the reference frequency change rate of the emergency control of the exit frequency set by the photovoltaic energy storage hybrid system and counting the reference frequency change rate by the counter;
the maintaining module is used for enabling the energy storage to maintain the current power output;
a stable frequency judgment controller and a frequency correction controller for realizing a frequency stable control strategy.
The invention has the beneficial effects that: firstly, two control strategies of transient frequency support and quasi-steady state frequency support are provided for different phases of the frequency response of the alternating current power grid after active disturbance, and the whole process support of the photovoltaic energy storage hybrid system on the frequency of the alternating current power grid is realized. And secondly, providing an energy storage capacity configuration and parameter setting method for maximizing the frequency modulation income and improving the operation economy of the photovoltaic energy storage hybrid system based on the price difference of different frequency modulation services of an electric power market mechanism, so as to dynamically adjust the maximum frequency emergency control coefficient and the rated speed of the energy storage to obtain primary and secondary frequency modulation control parameters for maximizing the operation economy of the photovoltaic energy storage hybrid system.
Drawings
Fig. 1 is a schematic diagram of control logic of a frequency emergency control strategy.
Fig. 2 is a control flow diagram of a frequency stabilization control strategy.
Fig. 3 is a schematic diagram of a photovoltaic energy storage hybrid system accessing an ac power grid.
Fig. 4 is an ac grid frequency simulation result of a photovoltaic power plant without energy storage and with the photovoltaic power plant configured to participate in frequency modulation through a photovoltaic energy storage hybrid system.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
A frequency control method of a photovoltaic energy storage hybrid system divides the frequency supporting process of an alternating current power grid after active disturbance into two stages of transient frequency supporting and quasi-steady state frequency supporting, wherein the transient frequency supporting stage adopts a frequency emergency control strategy; the quasi-steady-state frequency support stage adopts a frequency stability control strategy, and is a frequency control method for carrying out power compensation on the whole frequency process of an alternating current power grid.
The transient frequency support phase adopts a frequency emergency control strategy,the frequency response method aims to provide rapid frequency response when active disturbance occurs in the alternating current system and the frequency drops beyond a set range, so that the alternating current grid frequency is stabilized as soon as possible, and the frequency supporting capacity of the photovoltaic generator set is improved. The control logic of the frequency emergency control strategy is shown in fig. 1, f ref Is the reference frequency, f is the real-time frequency of the AC power grid, f' is the rate of change of the frequency of the AC power grid, and the value of the rate is equal to the differential of the real-time frequency of the AC power grid, f set ' is the reference frequency change rate of exit frequency emergency control set by the photovoltaic energy storage hybrid system, f s Is a threshold value for starting frequency emergency control, k r Is the frequency emergency control coefficient, k r-max Is the maximum frequency emergency control coefficient, Δf is the frequency deviation amount, and is the difference between the real-time frequency of the alternating current power grid and the reference frequency. The control logic of the frequency emergency control strategy is as follows: in a normal running state, the photovoltaic energy storage hybrid system continuously monitors the real-time frequency f of the alternating current power grid; when disturbance occurs in the AC power grid and the frequency deviation delta f exceeds the set range, the frequency emergency control function generates a control signal to the energy storage, and the energy storage is required to be controlled proportionally and the power is increased according to the frequency deviation delta f, and the coefficient of the proportional control is the frequency emergency control coefficient k r Thus the increased power is k r The power of the increase is denoted as P ×Δf sp The method comprises the steps of carrying out a first treatment on the surface of the In the process, the energy storage releases the stored energy according to the control signal to provide energy support; furthermore, the frequency emergency control coefficient k r Dynamically changing during control, frequency emergency control coefficient k r In direct proportion to the frequency change rate f 'of the alternating current power grid, when the value of the frequency change rate f' of the alternating current power grid is overlarge, the frequency emergency control coefficient k is formed r The value of which exceeds the maximum frequency emergency control coefficient k r-max When k is r Let k be r-max This means that the stored energy can provide faster energy support for faster frequency drops, providing an emergency support controlled output power P sp To stabilize the frequency of the AC network, but taking into account the energy storage capacity limitation, using a maximum frequency emergency control coefficient k r-max The excessive release of stored energy in a scene with excessive disturbance is avoided; comparing ac grid frequency changes by a comparatorThe conversion rate f' and the reference frequency change rate f of the emergency control of the exit frequency set by the photovoltaic energy storage hybrid system set 'and counting by a counter, when the frequency change rate f' of the continuous five times alternating current power grid is smaller than the reference frequency change rate f set by the photovoltaic energy storage hybrid system and exiting the frequency emergency control set ' when the energy storage enable holding module maintains the current power output as P sp No additional frequency emergency support is provided, and the frequency emergency control is exited.
And in the quasi-steady-state frequency support stage, a frequency stability control strategy is adopted, and power support is continuously provided through energy storage, so that the frequency of the disturbed power grid is ensured to be in a safe range after the stability. The control flow of the frequency stabilization control strategy is shown in fig. 2, and the frequency stabilization control strategy adjusts the frequency of the disturbed power grid within a safe range after the disturbed power grid is stabilized.
The frequency stabilization control strategy is realized by a stabilization frequency judgment controller and a frequency correction controller; and judging whether the frequency emergency control is finished or not by the stable frequency judging controller. The stable frequency judging controller monitors whether the absolute value of the frequency change rate of the alternating current power grid (namely, the differential of the real-time frequency of the alternating current power grid) is smaller than a preset value, if so, the stable frequency judging controller outputs a signal, the frequency correcting controller is started, and otherwise, the frequency correcting controller is not started;
the frequency correction controller monitors whether the stabilized ac grid frequency is within a safe range. If the stabilized AC network frequency is within the safe range, the frequency correction controller is not started, and if the stabilized AC network frequency is not within the safe range, the frequency correction controller is started, and at the moment, the energy storage starts to be carried out at a rated rate k s-max And (3) increasing the power output to the alternating current power grid until the frequency of the alternating current power grid enters a safe range, and stopping increasing the output power by the energy storage and maintaining the power.
In consideration of the fact that the frequency of the alternating current power grid adjusted by the frequency correction controller has an error with the set steady-state minimum value of the frequency of the alternating current power grid capable of safely running, whether the frequency of the alternating current power grid enters a safety range or not is monitored in real time in the process of continuously outputting stored energy, and a frequency margin is set, the frequency margin can ensure that the frequency of the alternating current power grid can maintain a continuously rising state and finally is stabilized in the safety range when the frequency of the alternating current power grid exceeds the lower limit of the safety range for the first time in the process of supporting energy storage, and therefore the frequency of the alternating current power grid is ensured to be continuously stabilized.
The frequency control method provided by the invention is based on price difference of different frequency modulation services of an electric power market mechanism, and the energy storage capacity configuration and parameter setting method for maximizing frequency modulation income and improving the operation economy of the photovoltaic energy storage hybrid system is provided.
Revenue in a photovoltaic energy storage hybrid system can be expressed mathematically as:
wherein B is the total income of the photovoltaic energy storage hybrid system, B ct To keep service revenue for spinning reserve, B f To provide revenue for FM services, B ct.pen Deficiency for rotating reserve of actual capacity not meeting system requirements, B f.pen A deficit created to provide frequency response compensation. B (B) ct、 B f The specific calculation method is as follows:
wherein C is contract capacity to provide spinning reserve, C rt1 、C rt2 The capacity of primary frequency modulation and secondary frequency modulation respectively, p is the reserve price of rotation, p f1 、p f2 The price per unit capacity of primary frequency modulation and secondary frequency modulation services respectively.
In addition, the total income also needs to be considered B ct.pen、 B f.pen Two defects, B ct.pen The calculation method of (2) is generally that the corresponding benefit is multiplied by onePenalty factor greater than 1, and B f.pen The calculation method of (2) is generally as follows:
wherein k is ct To penalty coefficients for rotational redundancy that do not meet system requirements, p LBMP And the marginal electricity price is the node. To sum up, the total revenue of a photovoltaic energy storage hybrid system can be expressed as:
obviously, the capacity C of the photovoltaic energy storage hybrid system for primary frequency modulation and secondary frequency modulation rt1 、C rt2 Respectively with the maximum frequency emergency control coefficient k of the stored energy r-max Rated rate k s-max There is a positive correlation between them, which is expressed in a simplified way as:
wherein m is 1 、m 2 Respectively, correlation coefficients, and delta P is obtained through off-line simulation D Is the most expected disturbance of the ac grid. Substituting the above formula into the calculation equation of the total income B of the photovoltaic energy storage hybrid system, the total income B of the photovoltaic energy storage hybrid system can be approximated to the maximum frequency emergency control coefficient k of energy storage r-max Rated rate k s-max Is a function of (2).
Therefore, the reserve price p is rotated, and the unit capacity price p of the primary frequency modulation and secondary frequency modulation service is rotated f1 、p f2 Dynamically adjusting the maximum frequency emergency control coefficient k of the stored energy by calculating the total revenue B of the expected photovoltaic stored energy hybrid system under expected disturbance under the condition of fluctuation r-max Rated rate k s-max The primary and secondary frequency modulation control parameters for maximizing the operation economy of the photovoltaic energy storage hybrid system can be obtained, namely:
of course, in the implementation process, the control parameters can be obtained by solving the maximum objective function of the total income of the photovoltaic energy storage hybrid system
The method can be simplified by establishing a parameter table through off-line simulation so as to ensure the engineering practicability of the method.
The invention also provides a frequency control system of the photovoltaic energy storage hybrid system, which comprises,
the monitoring device is used for continuously monitoring the real-time frequency of the alternating current power grid in the photovoltaic energy storage hybrid system;
a proportional controller for requiring proportional control of the stored energy and increasing the power of the transmission according to the amount of frequency deviation;
the comparator is used for comparing the frequency change rate of the alternating current power grid with the reference frequency change rate of the emergency control of the exit frequency set by the photovoltaic energy storage hybrid system and counting the reference frequency change rate by the counter;
the maintaining module is used for enabling the energy storage to maintain the current power output;
a stable frequency judgment controller and a frequency correction controller for realizing a frequency stable control strategy.
Application cases of the invention: the performance of the proposed photovoltaic energy storage hybrid system frequency control method and system taking into account the large-scale energy storage configuration of the photovoltaic power station is evaluated by modeling in PSCAD/EMTDC. In fig. 3, G1, G2 and G3 are conventional thermal power plants. The capacities of G1, G2 and G3 were 247.5 MW, 212.5 MW and 170MW, respectively. The energy storage is installed in a photovoltaic power station, and the capacity of the energy storage is 50MW. The loads L1, L2 and L3 are constant power loads, and rated active powers of the loads L1, L2 and L3 are 150MW, 135MW and 100MW respectively. Reference frequency f ref 50 to Hz, the reference frequency change rate f of the exit frequency emergency control set by the photovoltaic energy storage hybrid system set ' is 0.05, the frequency safety range of the frequency stability control setting is 49.8Hz-50.2Hz, and the maximum frequency emergency control coefficient k r-max 1. In the initial state, the frequency emergency control coefficient k r Set to 0.2. At t= s, the rated active power of the load L3 is increased by 38.5MW, the rated active powers of the load L1 and the load L2 are not changed, and fig. 4 shows the ac grid frequency simulation results of the photovoltaic power station without energy storage and in the case that the photovoltaic power station is configured to store energy in a frequency modulation manner through the photovoltaic energy storage hybrid system. As shown in fig. 4, in the case of no energy storage, the system was only changed by the conventional thermal power plant response frequency, and at 7.5s, the ac grid frequency curve reached the lowest point, at which the ac grid frequency was 49.20Hz, after which the ac grid frequency reached a steady state value at 20s, at which the ac grid frequency was 49.65Hz. Under the condition that the photovoltaic power station is configured with energy storage, through a frequency emergency control strategy of a photovoltaic energy storage hybrid system, the energy storage rapidly provides energy support for frequency compensation when the frequency deviation delta f exceeds a set range, and at the time of 7.0s, an alternating current power grid frequency curve reaches the lowest point, and at the moment, the alternating current power grid frequency is 49.45Hz, and is improved by about 0.25 Hz compared with the condition without energy storage; in addition, under the action of a frequency stability control strategy of the photovoltaic energy storage hybrid system, the frequency correction controller is started under the condition that the energy storage exceeds a safe range after the frequency of the alternating current power grid is stable, and k is used s-max The power output to the ac grid is increased for a rate until the ac grid frequency falls within a safe range. Under the action of the frequency stability control strategy of the photovoltaic energy storage hybrid system, the frequency of the alternating current power grid reaches a steady state value at 32.5s, and at the moment, the frequency of the alternating current power grid is 49.8Hz, and compared with the condition without energy storage, the frequency of the alternating current power grid is improved by 0.15Hz.
According to simulation results, the invention can realize power adjustment of the whole alternating current power grid frequency process after active disturbance, improve the lowest frequency point of the alternating current power grid after active disturbance, and effectively improve the alternating current power grid frequency supporting capacity of the photovoltaic generator set.
Claims (4)
1. The frequency control method of the photovoltaic energy storage hybrid system is characterized in that the frequency supporting process of an alternating current power grid after active disturbance is divided into two stages of transient frequency supporting and quasi-steady frequency supporting;
the transient frequency support stage adopts a frequency emergency control strategy: in the state of normal operation of the vehicle,the photovoltaic energy storage hybrid system continuously monitors the real-time frequency f of the alternating current power grid; when disturbance occurs in the alternating current power grid and the frequency deviation delta f exceeds a set range, the frequency emergency control function generates a control signal to the energy storage, the energy storage is required to be controlled proportionally, the power is increased according to the frequency deviation delta f, and the coefficient of the proportional control is the frequency emergency control coefficient k r The power of the increased power is k r XΔf, the increased power is denoted as P sp The method comprises the steps of carrying out a first treatment on the surface of the In the process, the energy storage releases the stored energy according to the control signal to provide energy support; furthermore, the frequency emergency control coefficient k r Dynamically changing during control, frequency emergency control coefficient k r In direct proportion to the frequency change rate f 'of the alternating current power grid, when the value of the frequency change rate f' of the alternating current power grid is overlarge, the frequency emergency control coefficient k is formed r The value of which exceeds the maximum frequency emergency control coefficient k r-max When k is r Let k be r-max The method comprises the steps of carrying out a first treatment on the surface of the Comparing the alternating current power grid frequency change rate f' with the reference frequency change rate f set by the photovoltaic energy storage hybrid system and used for exiting frequency emergency control set 'and counting by a counter, when the frequency change rate f' of the continuous five times alternating current power grid is smaller than the reference frequency change rate f set by the photovoltaic energy storage hybrid system and exiting the frequency emergency control set ' when the energy storage enable holding module maintains the current power output as P sp No additional frequency emergency support is provided, and the frequency emergency control is exited;
the quasi-steady frequency support stage adopts a frequency stability control strategy, and the frequency stability control strategy is realized by a stable frequency judgment controller and a frequency correction controller; judging whether the frequency emergency control is finished or not by the stable frequency judging controller; the stable frequency judging controller monitors whether the absolute value of the frequency change rate of the alternating current power grid is smaller than a preset value, if so, the stable frequency judging controller outputs a signal, the frequency correction controller is started, and otherwise, the frequency correction controller is not started;
the frequency correction controller monitors whether the frequency of the stabilized alternating current power grid can be within a safe range; if the stabilized AC power grid frequency is within the safe range, the frequency correction controller is not started, if the stabilized AC power grid frequency is within the safe rangeIf the network frequency is not within the safe range, the frequency correction controller is activated, and the stored energy begins to flow at a nominal rate k s-max And (3) increasing the power output to the alternating current power grid until the frequency of the alternating current power grid enters a safe range, and stopping increasing the output power by the energy storage and maintaining the power.
2. The method according to claim 1, wherein during the continuous output of the stored energy, whether the ac grid frequency enters a safety range is monitored in real time, and a frequency margin is set, wherein the frequency margin ensures that the ac grid frequency can maintain a continuous rising state and finally stabilize within the safety range when the ac grid frequency exceeds a lower limit of the safety range for the first time during the energy storage supporting process, thereby ensuring the continuous stability of the ac grid frequency.
3. The method of claim 1, wherein the total revenue of the photovoltaic energy storage hybrid system is expressed as:
b is the total income of the photovoltaic energy storage hybrid system, B ct To keep service revenue for spinning reserve, B f To provide revenue for FM services, B ct.pen Deficiency for rotating reserve of actual capacity not meeting system requirements, B f.pen Deficit to provide frequency response compensation, C is contract capacity to provide spinning reserve, C rt1 、C rt2 The capacity of primary frequency modulation and secondary frequency modulation respectively, p is the reserve price of rotation, p f1 、p f2 The price per unit capacity, k, of primary frequency modulation and secondary frequency modulation services respectively ct To penalty coefficients for rotational redundancy that do not meet system requirements, p LBMP The marginal electricity price of the node;
capacity C of photovoltaic energy storage hybrid system for primary frequency modulation and secondary frequency modulation rt1 、C rt2 Respectively with the storageMaximum frequency emergency control coefficient k of energy r-max Rated rate k s-max A positive correlation exists between the two;
wherein m is 1 、m 2 Respectively, correlation coefficients, and delta P is obtained through off-line simulation D The maximum expected disturbance of the alternating current power grid; in the rotation reserve clearing price p, primary frequency modulation and secondary frequency modulation service unit capacity price p f1 、p f2 Dynamically adjusting the maximum frequency emergency control coefficient k of the stored energy by calculating the total revenue B of the expected photovoltaic stored energy hybrid system under expected disturbance under the condition of fluctuation r-max Rated rate k s-max And obtaining primary and secondary frequency modulation control parameters for maximizing the operation economy of the photovoltaic energy storage hybrid system.
4. A system for implementing the photovoltaic energy storage hybrid system frequency control method of claim 1, comprising,
the monitoring device is used for continuously monitoring the real-time frequency of the alternating current power grid in the photovoltaic energy storage hybrid system;
a proportional controller for requiring proportional control of the stored energy and increasing the power of the transmission according to the amount of frequency deviation;
the comparator is used for comparing the frequency change rate of the alternating current power grid with the reference frequency change rate of the emergency control of the exit frequency set by the photovoltaic energy storage hybrid system and counting the reference frequency change rate by the counter;
the maintaining module is used for enabling the energy storage to maintain the current power output;
a stable frequency judgment controller and a frequency correction controller for realizing a frequency stable control strategy.
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