Method for multi-tank electrolysis cluster to participate in power grid frequency response interaction

Abstract

The invention discloses a method for a multi-tank electrolysis cluster to participate in power grid frequency response interaction, and belongs to the field of power system operation regulation and control. After an electrolysis cluster receives a frequency response regulation and control instruction, a total droop coefficient D and a total inertia coefficient H are generated according to maximum power reserve and maximum system maximum frequency deviation; secondly, droop coefficients of different electrolytic cells are generated according to the operating power, the power limit and the total droop coefficient of the electrolytic cluster of the different electrolytic cells; finally, generating respective inertia coefficients of different electrolytic cells according to the droop coefficients of the electrolytic cells and the total inertia coefficient of the electrolytic cluster; compared with a traditional frequency response method, the frequency response method considers the difference of operation conditions of different electrolytic cells during frequency response coefficient allocation, and maximizes the power reserve of an electrolysis cluster in frequency response through the optimal allocation of the frequency response coefficients, so that the frequency fluctuation of a power system after power imbalance is reduced, and the service life of the power system is prolonged. And the safety, reliability and stability of the system are improved.

Description

Technical Field

[0001] The present invention belongs to the field of power system operation and regulation, and specifically relates to a method for a multi-tank electrolysis cluster to participate in a power grid frequency response interaction. Background Art

[0002] Climate change is driving the decarbonization of the energy sector. The concept of connecting renewable energy to the power system and converting excess energy into hydrogen through water electrolyzers has attracted much attention due to its environmental and economic benefits. Currently, there are three main types of electrolyzers: alkaline electrolyzers, proton exchange membrane electrolyzers, and solid oxide electrolyzers, of which alkaline electrolyzers are the most widely used in industry.

[0003] As the proportion of renewable energy increases, the key challenge facing the power system is the reduction of system inertia and primary frequency response reserves due to the transition from synchronous machines to inverter-based renewable energy, which threatens the frequency stability of the system. To address this problem, scholars have proposed integrating alkaline electrolyzers into the frequency response of the power system due to its ability to quickly adjust the operating power. However, an alkaline water electrolysis cluster (AWEP) usually consists of multiple electrolyzer stacks, each operating at a different power level. How to fully utilize the power reserve capacity of the electrolysis cluster and effectively distribute the damping and inertia coefficients among these stacks has become a major challenge.

[0004] To this end, the present invention analyzes the operating characteristics of alkaline electrolyzers and proposes a frequency response coefficient allocation method for a multi-tank electrolysis cluster suitable for large-scale electrolysis clusters participating in power system frequency response auxiliary services. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for a multi-tank electrolysis cluster to participate in the interactive frequency response of a power grid, maximize the power reserve provided by the electrolysis cluster in the frequency response, optimize the frequency response capability of the electrolysis cluster, and improve the stability of the power system.

[0006] The object of the present invention can be achieved by the following technical solution: a method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction, the method comprising the following steps:

[0007] Step 1: When the electrolysis cluster receives the frequency response command, the electrolysis cluster generates the total droop coefficient D and the total inertia coefficient H.

[0008] and assigning coefficients to the different electrolysers in operation;

[0009] Step 2: The electrolyzer generates a droop coefficient when the electrolyzer power is reduced and a droop system when the power is increased according to its own power, power limit and the total droop coefficient of the electrolysis cluster;

[0010] Step 3: The electrolyzer obtains the inertia coefficient when the power is increased and the inertia coefficient when the power is decreased according to the droop coefficient and the total inertia coefficient when the power is increased / decreased;

[0011] Step 4: The electrolyzer performs frequency response based on the generated droop coefficient and inertia coefficient.

[0012] As an improvement of the present invention, the method for generating the electrolysis cluster droop coefficient in step 1 is:

[0013]

[0014] In the formula, MPR represents the maximum power support that the electrolysis cluster can provide at this time, Δf max is the maximum frequency fluctuation acceptable to the power system, D awep represents the total droop system of the frequency response of the electrolytic cluster,

[0015] The calculation method of the maximum power support MPR that the electrolysis cluster can provide is:

[0016]

[0017] In the formula, the subscript number represents the number of the electrolytic cell, P max Represents the maximum power of the electrolytic cell, P ini Represents the initial power of the electrolyzer.

[0018] In step 1, when the electrolysis cluster allocates coefficients to different electrolyzers in operation, in order to ensure the overall characteristics of the electrolysis cluster frequency response, there should be:

[0019]

[0020] Where D awep,i With H awep,i represent the droop coefficient and inertia coefficient of the i-th electrolytic cell respectively.

[0021] Step 2: When the electrolyzer generates its own frequency response droop coefficient, in order to ensure that the allocated droop coefficient makes all electrolyzers reach the power limit under the same frequency fluctuation, because the deviation between the operating power of the electrolyzer and the maximum power limit and the minimum power limit is not equal, the droop coefficient D of the electrolyzer when the power rises awep,i,up The droop coefficient D when the power drops awep,down,i The values ​​are different.

[0022] Step 2: When the electrolyzer generates its own frequency response droop coefficient, the droop coefficient D of the electrolyzer when the power increases awep,i,up The calculation method is:

[0023]

[0024] Step 2: When the electrolyzer generates its own frequency response droop coefficient, the droop coefficient D of the electrolyzer when the power decreases awep,i,down The calculation method is:

[0025]

[0026] In the formula, the subscript number represents the number of the electrolytic cell, P min Represents the minimum power of the electrolyzer.

[0027] In step 3, when the electrolyzer generates its own frequency response inertia coefficient, the inertia coefficient when the power rises should be proportional to the droop coefficient when the power rises:

[0028]

[0029] In step 3, when the electrolyzer generates its own frequency response inertia coefficient, the inertia coefficient of the electrolyzer when the power decreases should be proportional to the droop coefficient when the power decreases:

[0030]

[0031] In step 4, when the electrolyzer is performing frequency response, the power should be adjusted up according to the following model:

[0032]

[0033] In the formula, ΔP represents the power change value, Δf is the frequency offset, and ref represents the target value of the frequency response adjustment.

[0034] The following model should be followed when power is reduced:

[0035]

[0036] Beneficial effects of the present invention:

[0037] The method of the present invention fully considers the differences in the operating states (power) of different electrolyzers when the electrolysis cluster participates in the frequency response. Through the optimal allocation between the frequency response system slots, different electrolyzers can reach the operating limit power under the same frequency deviation, maximizing the power reserve that the electrolysis cluster can provide in the frequency response, thereby reducing the frequency deviation of the system after a fault. By using this frequency response coefficient allocation method, the electrolysis cluster operator can obtain more benefits in the ancillary service market.

[0038] The present invention innovatively proposes to consider different droop coefficients and inertia coefficients when adjusting power up and down, so as to maximize the power reserve provided to the power system according to the current operating status of the electrolyzer and improve the frequency response state of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 is a flow chart of the frequency response coefficient slot allocation method of the present invention,

[0041] Figure 2 This is a qualitative comparison chart of the effects of the strategy proposed by the present invention and the general frequency response strategy.

[0042] Figure 3 This is a simulation comparison diagram of the effects of the strategy proposed by the present invention and the general frequency response strategy. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Embodiment: The present invention relates to a method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction, the core features of which are: when the electrolysis cluster receives a frequency response instruction, it is necessary to generate a droop coefficient D and allocate the coefficient to different electrolysis cells in operation;

[0045] To maximize the power reserve provided by the electrolysis cluster in the frequency response, the assigned droop factor should ensure that all electrolyzers reach their power limit under the same frequency fluctuation;

[0046] Since it is related to the electrolysis power limit, the droop coefficients for the same electrolyzer when the power increases and decreases are not equal and need to be considered separately;

[0047] To ensure power synchronization of different electrolyzers, the inertia coefficient should be proportional to its droop coefficient;

[0048] This embodiment assumes an electrolysis cluster consisting of two electrolyzers, the maximum power of the electrolyzers is 14.4MW, the minimum power is 2.4MW, and the initial operating powers of the two electrolyzers are 12.4MW and 4.4MW respectively.

[0049] Combined with the system parameters, the maximum power support MPR that the electrolysis cluster can provide at this time can be obtained as follows:

[0050]

[0051] That is, the maximum power support MPR is 12MW. Assuming the maximum frequency deviation Δf max is 0.1Hz, the droop coefficient D of the electrolytic cluster can be calculated:

[0052]

[0053] The frequency response inertia coefficient H of the electrolytic cluster awep Set to 400.

[0054] Furthermore, the droop coefficient of electrolytic cell 1 when the power is increased can be obtained as:

[0055]

[0056] The droop coefficient of electrolyzer 1 when the power is reduced is:

[0057]

[0058] The droop coefficient of electrolyzer 2 when the power is increased is:

[0059]

[0060] The droop coefficient of electrolyzer 2 when the power is reduced is:

[0061]

[0062] Furthermore, the inertia coefficient of the electrolytic cell 1 when the power is increased can be obtained as:

[0063]

[0064] The inertia coefficient of electrolyzer 1 when the power is reduced is:

[0065]

[0066] The inertia coefficient of electrolyzer 2 when the power is increased is:

[0067]

[0068] The inertia coefficient of electrolyzer 2 when the power is reduced is:

[0069]

[0070] Furthermore, the frequency response model of the electrolytic cell 1 when the power is increased can be obtained as:

[0071]

[0072] The frequency response model of electrolyzer 1 when the power is reduced is:

[0073]

[0074] The frequency response model of electrolyzer 2 when the power is increased is:

[0075]

[0076] The frequency response model of electrolyzer 2 when the power is reduced is:

[0077]

[0078] To further illustrate the superiority of the proposed method, the effects of the proposed electrolyzer cluster frequency response strategy and the general strategy are compared when the 100MW power system encounters a 10MW power imbalance. The results are shown in the attached figure. Figure 3 As shown in the figure, after the system power is unbalanced, the steady-state frequency deviation is 0.071Hz under the proposed strategy, and the steady-state frequency deviation is 0.104Hz under the general strategy, which proves that the electrolyzer cluster can provide more power reserve and reduce frequency deviation under the proposed strategy.

[0079] Attached Figure 2 The proposed cluster frequency response strategy is qualitatively compared with the general frequency response strategy. As shown in the figure, under power imbalance, the proposed frequency response strategy can achieve power balance with smaller frequency changes, reducing the system frequency deviation, which proves the superiority of the proposed strategy.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0081] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for multi-tank electrolysis clusters to participate in grid frequency response interaction, characterized in that: The method comprises the following steps: Step 1: When the electrolysis cluster receives the frequency response command, it generates the total droop coefficient D and the total inertia coefficient H, and distributes the coefficients to the different electrolyzers in operation; Step 2: The electrolyzer generates a droop coefficient when the electrolyzer power is reduced and a droop system when the power is increased according to its own power, power limit and the total droop coefficient of the electrolysis cluster; Step 3: The electrolyzer obtains the inertia coefficient when the power is increased and the inertia coefficient when the power is decreased according to the droop coefficient and the total inertia coefficient when the power is increased / decreased; Step 4: The electrolyzer performs frequency response based on the generated droop coefficient and inertia coefficient.

2. According to claim 1, a method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction is characterized in that: The electrolysis cluster droop coefficient generation method in step 1 is: In the formula, MPR represents the maximum power support that the electrolysis cluster can provide at this time, Δf max is the maximum frequency fluctuation acceptable to the power system, D awep represents the total droop system of the frequency response of the electrolytic cluster, The calculation method of the maximum power support MPR that the electrolysis cluster can provide is: In the formula, the subscript number represents the number of the electrolytic cell, P max Represents the maximum power of the electrolytic cell, P ini Represents the initial power of the electrolyzer.

3. The method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction according to claim 1, characterized in that: Step 1: When the electrolysis cluster allocates coefficients to different electrolyzers in operation, in order to ensure the overall characteristics of the electrolysis cluster frequency response, there should be: Where D awep,i With H awep,i represent the droop coefficient and inertia coefficient of the i-th electrolytic cell respectively.

4. A method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction according to claim 1, characterized in that: Step 2: When the electrolyzer generates its own frequency response droop coefficient, in order to ensure that the allocated droop coefficient makes all electrolyzers reach the power limit under the same frequency fluctuation, because the deviation between the operating power of the electrolyzer and the maximum power limit and the minimum power limit is not equal, the droop coefficient D of the electrolyzer when the power rises awep,i,up The droop coefficient D when the power decreases awep,down,i The values ​​are different.

5. The method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction according to claim 1, characterized in that: Step 2: When the electrolyzer generates its own frequency response droop coefficient, the droop coefficient D of the electrolyzer when the power increases awep,i,up The calculation method is:

6. A method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction according to claim 1, characterized in that: Step 2: When the electrolyzer generates its own frequency response droop coefficient, the droop coefficient D of the electrolyzer when the power decreases awep,i,down The calculation method is: In the formula, the subscript number represents the number of the electrolytic cell, P min Represents the minimum power of the electrolyzer.

7. A method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction according to claim 1, characterized in that: In step 3, when the electrolyzer generates its own frequency response inertia coefficient, the inertia coefficient when the power rises should be proportional to the droop coefficient when the power rises:

8. The method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction according to claim 1, characterized in that: In step 3, when the electrolyzer generates its own frequency response inertia coefficient, the inertia coefficient of the electrolyzer when the power decreases should be proportional to the droop coefficient when the power decreases:

9. The method for a multi-tank electrolysis cluster to participate in a grid frequency response interaction according to claim 1, characterized in that: In step 4, when the electrolyzer is performing frequency response, the power should be adjusted up according to the following model: In the formula, ΔP represents the power change value, Δf is the frequency offset, and ref represents the target value of the frequency response adjustment. The following model should be followed when power is reduced:

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