A unit commitment method for primary frequency modulation of a new type of power system assisted by liquid hydrogen superconducting co-melting energy storage

Abstract

The application belongs to the technical field of power grid regulation, and discloses a unit combination method for primary frequency modulation of a new type of power system assisted by liquid hydrogen superconducting eutectic energy storage, which comprises the following steps: obtaining data of the power system, establishing a primary frequency modulation unit combination model, including an objective function and constraint conditions, the objective function being to minimize the total economic cost, and the constraint conditions being to make the operation of the new type of power system meet the system maximum frequency change rate constraint, the system frequency minimum point constraint and the system quasi-steady frequency constraint, solving the primary frequency modulation unit combination model, and outputting a primary frequency modulation unit combination control strategy. The above three constraints are obtained through complex analysis and deduction of the new type of power system, which can greatly reduce the complexity while ensuring effectiveness. Simulation verification shows that when the above method is used for primary frequency modulation of the liquid hydrogen superconducting eutectic energy storage assisted system, the system maximum frequency change rate, the maximum frequency deviation and the quasi-steady frequency deviation are all improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power grid regulation, and more particularly to a unit combination method for liquid hydrogen superconducting eutectic energy assisted primary frequency modulation of a new power system. BACKGROUND

[0002] To achieve the goal of "carbon peak and carbon neutral", the new power system is developing steadily, and the scale of wind and solar energy grid-connected is increasing day by day. The significant volatility and randomness of new energy cause potential problems such as increased difficulty in system frequency modulation. The response speed of traditional synchronous units is slow and the climbing power is limited, and frequent frequency modulation instructions cause mechanical equipment wear and tear, thereby affecting the service life of the equipment. Although existing research focuses on the method and control of energy storage technology participating in the frequency modulation process, the control effect is not ideal. Moreover, in addition to traditional units and renewable energy, the new power system usually has liquid hydrogen superconducting eutectic energy storage equipment, and there is currently no application of liquid hydrogen superconducting eutectic energy storage participating in the auxiliary system primary frequency modulation.

[0003] Therefore, based on the characteristics of hydrogen energy storage and superconducting magnetic energy storage in liquid hydrogen superconducting eutectic energy storage, combined with the dynamic frequency modulation characteristics of the power system, the coordination of liquid hydrogen superconducting eutectic energy storage and traditional synchronous units is considered on the economic level of the system to achieve efficient frequency support, which still needs further research. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the application provides a unit combination method for liquid hydrogen superconducting eutectic energy assisted primary frequency modulation of a new power system, which aims to consider the coordination of liquid hydrogen superconducting eutectic energy storage and traditional synchronous units on the economic level of the system to achieve efficient frequency support based on the characteristics of hydrogen energy storage and superconducting magnetic energy storage in liquid hydrogen superconducting eutectic energy storage, combined with the dynamic frequency modulation characteristics of the power system.

[0005] To achieve the above-mentioned purpose, according to the first aspect of the application, a unit combination method for liquid hydrogen superconducting eutectic energy assisted primary frequency modulation of a new power system is provided, which comprises:

[0006] acquiring data of a new power system, the new power system comprising traditional synchronous units, renewable energy generating units and liquid hydrogen superconducting eutectic energy storage equipment;

[0007] establishing a primary frequency modulation unit combination model of the new power system, the model comprising an objective function and constraint conditions, the objective function being to minimize the total economic cost of the system, and the constraint conditions being to make the operation of the system meet the traditional unit combination constraint conditions while meeting the system maximum frequency change rate constraint, the system frequency minimum point constraint and the system quasi-steady frequency constraint:

[0008] the system maximum frequency change rate constraint comprises:

[0009] The system's minimum frequency constraint includes:

[0010] The quasi-steady-state frequency constraints of the system include:

[0011] In the formula: the subscripts k, t, i, and j represent the k-th frequency regulation cycle, time t within the frequency regulation cycle, the i-th synchronous generator, and the j-th liquid hydrogen superconducting co-existing energy storage device, respectively. f represents the power disturbance at t=0s during the k-th cycle of power system frequency regulation; 0 The system's rated frequency; This is a binary variable for the synchronous generator unit's switch; a value of 1 indicates that the synchronous generator unit is in operation, and a value of 0 indicates that the synchronous generator unit is not in operation. These are the inertia coefficients of the synchronous generator and the superconducting magnetic energy storage device, respectively. This represents the system's maximum rate of frequency change. This refers to the primary frequency regulation power of the synchronous generator unit; These are the gain coefficients for the synchronous generator unit and the liquid hydrogen superconducting co-existing energy storage device, respectively. The system damping coefficient; The threshold for the lowest frequency point; The quasi-steady-state frequency threshold of the system;

[0012] Solve the primary frequency regulation unit combination model and output the unit combination control strategy for each cycle.

[0013] In some embodiments, the system frequency minimum point constraint is converted into a reconstructed system frequency minimum point constraint after linearization:

[0014]

[0015] In the formula: The primary frequency regulation power of the synchronous generator unit after linearization. Approximate value, This represents the minimum total inertia coefficient of the system. This is the response time constant of the synchronous generator unit.

[0016] In some embodiments, the constraints that enable the operation of the system to simultaneously satisfy the system maximum rate of change constraint, the system minimum frequency constraint, and the system quasi-steady-state frequency constraint can be reconfigured within the unit combination model as synchronous generator constraints, liquid hydrogen superconducting co-existing energy storage device constraints, deformed system minimum frequency constraint, and deformed system quasi-steady-state frequency constraint.

[0017] Before the combination model of the primary frequency modulation unit is established, the current system frequency is acquired, and the operation state of the liquid hydrogen superconducting co-melting energy storage device is selected according to the current system frequency, and the corresponding constraint condition is constructed;

[0018] When the system frequency is lower than the rated value, the fuel cell in the liquid hydrogen superconducting co-melting energy storage device is put into operation to perform positive frequency modulation:

[0019] The synchronous generator constraint comprises:

[0020]

[0021] In the formula: is the actual reserved capacity of the synchronous unit for adjusting the lowest point of the system frequency, is the actual reserved capacity of the synchronous unit for adjusting the quasi-steady frequency of the system, is the power generated by the synchronous unit, is the maximum power generated by the synchronous unit;

[0022] The liquid hydrogen superconducting co-melting energy storage device constraint is a fuel cell device constraint, comprising:

[0023]

[0024] In the formula: is the actual reserved capacity of the fuel cell device for adjusting the lowest point of the system frequency, is the actual reserved capacity of the fuel cell device for adjusting the quasi-steady frequency of the system, is the gain coefficient of the fuel cell, is the working power of the fuel cell device, is the maximum working power of the fuel cell device;

[0025] The deformed system frequency lowest point constraint comprises:

[0026]

[0027] The deformed system quasi-steady frequency constraint comprises:

[0028]

[0029] In some embodiments, when the system frequency is higher than the rated value, the water electrolysis hydrogen production device in the liquid hydrogen superconducting co-melting energy storage device is put into operation to perform negative frequency modulation:

[0030] The synchronous generator constraint comprises:

[0031]

[0032] The liquid hydrogen superconducting co-melting energy storage device constraint is a water electrolysis hydrogen production device constraint, comprising:

[0033]

[0034] In the formula: is the actual reserved capacity of the water electrolysis hydrogen production device for adjusting the minimum point of the system frequency, is the actual reserved capacity of the water electrolysis hydrogen production device for adjusting the quasi-steady frequency of the system, is the working power of the water electrolysis hydrogen production device, is the maximum working power of the water electrolysis hydrogen production device; is the gain coefficient of the fuel cell;

[0035] The deformed system frequency minimum point constraint comprises:

[0036]

[0037] The deformed system quasi-steady frequency constraint comprises:

[0038]

[0039] In some embodiments, the objective function is:

[0040]

[0041] In the formula: are the generation cost, start-up cost, and shut-down cost of the synchronous unit, respectively, is the working power of the fuel cell device, is the working power of the water electrolysis hydrogen production device, FC is the unit working cost of the fuel cell device, EL is the unit working cost of the water electrolysis hydrogen production device, cur is the power unit penalty cost of abandoning renewable energy, is the renewable energy abandonment ratio, is the renewable energy power abandoned, and subscript w is the wth renewable energy generator.

[0042] In some embodiments, the constraint condition further comprises:

[0043] The system power balance constraint, the system spinning reserve constraint, the unit output upper and lower limit constraint, the liquid hydrogen superconducting co-melting energy storage device power upper and lower limit constraint, the synchronous unit minimum start-stop time constraint, and the synchronous unit power ramping rate constraint.

[0044] In some embodiments, the inertia coefficient of the superconducting magnetic energy storage device The rated power of the superconducting magnetic energy storage device and the system maximum frequency change rate satisfies:

[0045]

[0046] According to a second aspect of the present application, an electronic device is provided, comprising a memory and a processor, the memory storing a computer program, and the processor implementing the steps of the method according to any one of the above when executing the computer program.

[0047] According to a third aspect of the present application, a computer readable storage medium is provided, storing a computer program, the computer program being executed by a processor to implement the steps of the method according to any one of the above.

[0048] According to a fourth aspect of the present application, a computer program product is provided, comprising a computer program or instructions, the computer program or instructions being executed by a processor to implement the steps of the method according to any one of the above.

[0049] Overall, compared with the prior art, the unit combination method for liquid hydrogen superconducting co-melting energy assisted primary frequency modulation of a new type of power system provided by the present application mainly has the following beneficial effects:

[0050] 1. The unit combination method for liquid hydrogen superconducting co-melting energy assisted primary frequency modulation of a new type of power system provided by the present application introduces liquid hydrogen superconducting co-melting energy equipment for auxiliary frequency modulation. In liquid hydrogen superconducting co-melting energy, the superconducting magnetic energy storage device has extremely fast response speed but short working time, can realize system frequency inertia support, and reduce the system frequency change rate, while the liquid hydrogen energy storage device can be used to control the system frequency minimum point and quasi-steady frequency due to its large energy storage capacity, thereby guaranteeing the safety and stability of the system frequency. Through the coordination of the liquid hydrogen superconducting co-melting energy equipment and the traditional synchronous unit, the frequency safety constraint of the primary frequency modulation system is constructed, so that when a frequency safety event occurs, the system simultaneously satisfies the system maximum frequency change rate constraint, the system frequency minimum point constraint and the system quasi-steady frequency constraint. The above three constraints are obtained through complex analysis and derivation of the new type of power system containing liquid hydrogen superconducting co-melting energy, and can reflect the complex dynamic frequency modulation process of the system, while guaranteeing effectiveness and greatly reducing complexity. Simulation verification shows that when liquid hydrogen superconducting co-melting energy is used to assist primary frequency modulation based on the above method, compared with a system that does not use liquid hydrogen superconducting co-melting energy to assist primary frequency modulation, when a system frequency safety event occurs, the system maximum frequency change rate, maximum frequency deviation and quasi-steady frequency deviation are improved, effectively proving the outstanding advantages of liquid hydrogen superconducting co-melting energy in maintaining the safety and stability of the system frequency, improving power quality, etc.

[0051] 2. In some embodiments, the system frequency minimum point constraint is reconstructed by using a linearization frequency method to solve the problem of high degree of model nonlinearity, which can reduce the difficulty of solving.

[0052] 3. In some embodiments, based on the three security constraints, combined with the working state of the synchronous unit, the synchronous generator constraint, the liquid hydrogen superconducting co-melting energy storage device constraint, the deformed system frequency minimum point constraint and the deformed system quasi-steady frequency constraint that meet the above three security constraints can be constructed, which can further simplify the calculation and improve the accuracy of the model. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a step flow chart of the frequency modulation method of the liquid hydrogen superconducting co-melting energy storage auxiliary primary frequency modulation in an embodiment of the present application;

[0054] Figure 2 is a framework diagram of the power system in an embodiment of the present application;

[0055] Figure 3 is a comparison diagram of the maximum frequency change rate under three different frequency modulation methods when the system is forward frequency modulated in an embodiment of the present application;

[0056] Figure 4 is a comparison diagram of the maximum frequency deviation under three different frequency modulation methods when the system is forward frequency modulated in an embodiment of the present application;

[0057] Figure 5 is a comparison diagram of the quasi-steady frequency deviation under three different frequency modulation methods when the system is forward frequency modulated in an embodiment of the present application;

[0058] Figure 6 is a comparison diagram of the maximum frequency change rate under three different frequency modulation methods when the system is negative frequency modulated in an embodiment of the present application;

[0059] Figure 7 is a comparison diagram of the maximum frequency deviation under three different frequency modulation methods when the system is negative frequency modulated in an embodiment of the present application;

[0060] Figure 8 is a comparison diagram of the quasi-steady frequency deviation under three different frequency modulation methods when the system is negative frequency modulated in an embodiment of the present application. DETAILED DESCRIPTION

[0061] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0062] Embodiment 1

[0063] As Figure 1 shown is a step flow chart of a unit combination method for primary frequency modulation of a liquid hydrogen superconducting co-melting energy storage assisted new power system in an embodiment of the present application, and the core steps thereof will be described in detail below.

[0064] Step S1: Obtain the data of the new power system, which includes traditional synchronous units, renewable energy generator units and liquid hydrogen superconducting co-melting energy storage devices.

[0065] As Figure 2 shown is a frame diagram of the power system in an embodiment of the present application, which exemplarily shows six nodes 1-6, node 1 is connected to synchronous unit (steam turbine) G1, node 2 is connected to synchronous unit G3 and wind power W3, node 3 is connected to synchronous unit G2 and wind power W2, node 4 is connected to liquid hydrogen superconducting co-melting energy storage device L1QHYSMES2, and node 5 is connected to liquid hydrogen superconducting co-melting energy storage device L1QHYSMES1.

[0066] Among them, the liquid hydrogen superconducting co-melting energy storage device mainly includes three core sub-components: superconducting magnetic energy storage device, water electrolysis hydrogen production device and fuel cell device.

[0067] The data of the power system that needs to be obtained includes: system network structure, parameters of traditional synchronous units, parameters of liquid hydrogen superconducting co-melting energy storage devices and parameters of renewable energy generator units. The system network structure includes the number of nodes and the installation position of each device. The parameters of the liquid hydrogen superconducting co-melting energy storage device include the capacity, inertia coefficient and droop control coefficient of the three core sub-components. The parameters of the traditional synchronous unit include the capacity, minimum power generation, climbing limit, start-stop machine cost, minimum start (stop) time, inertia coefficient, droop control coefficient and response time coefficient. The parameters of the renewable energy generator unit include the power generation.

[0068] Step S2: Establish a primary frequency modulation unit combination model of the liquid hydrogen superconducting co-melting energy storage assisted new power system, the model includes an objective function and constraint conditions, the objective function is to minimize the total economic cost of the system, and the constraint conditions make the operation of the system meet the system maximum frequency change rate constraint, the system frequency minimum point constraint and the system quasi-steady frequency constraint on the basis of meeting the traditional unit combination constraint condition.

[0069] The system maximum frequency change rate constraint includes:

[0070]

[0071] The system frequency minimum constraint includes:

[0072]

[0073] The system quasi-steady frequency constraint includes:

[0074]

[0075] In the formula, the subscripts k, t, i, j respectively represent the kth frequency modulation period, the t moment in the frequency modulation period, the ith synchronous generator unit, and the jth liquid hydrogen superconducting co-melting energy storage device; is the power disturbance at t=0s in the kth frequency modulation period of the power system; f 0 is the system rated frequency; is a synchronous generator unit switch binary variable, taking 1 indicates that the synchronous generator unit is put into operation, and taking 0 indicates that the synchronous generator unit is not put into operation; are respectively the inertia coefficients of the synchronous generator unit and the superconducting magnetic energy storage device, is the system maximum frequency change rate; is the primary frequency modulation power of the synchronous generator unit; are respectively the gain coefficients of the synchronous generator unit and the liquid hydrogen superconducting co-melting energy storage device; is the system damping coefficient; is the frequency minimum threshold; is the system quasi-steady frequency threshold.

[0076] The frequency minimum threshold The system quasi-steady frequency threshold The system maximum frequency change rate are all set values, the inertia coefficients, the rated power, and the gain coefficients are all known parameters, in order to guarantee that the superconducting magnet output is within a safe range, the inertia coefficient of the superconducting magnetic energy storage device The rated power of the superconducting magnetic energy storage device and the system maximum frequency change rate are set values, and satisfy:

[0077]

[0078] As the liquid hydrogen superconducting co-melting energy storage device contains three core sub-components of superconducting magnetic energy storage device, water electrolysis hydrogen production device and fuel cell device, it can be understood that when the load demand of the power system is higher than the power generation of the system, the system frequency decreases, at this time, the fuel cell device in the liquid hydrogen superconducting co-melting energy storage device should be operated, that is, the fuel cell device participates in frequency modulation, the water electrolysis hydrogen production device only participates in power balance without reserving frequency modulation capacity, hydrogen combustion generates electric energy to supply power and perform positive frequency modulation; when the load demand is lower than the power generation of the system, the system frequency increases, at this time, the water electrolysis hydrogen production device in the liquid hydrogen superconducting co-melting energy storage device should be operated, and water is used to produce hydrogen by using electric energy to realize energy storage, that is, the water electrolysis hydrogen production device participates in frequency modulation, the fuel cell device only participates in power balance without reserving frequency modulation capacity, and performs negative frequency modulation.

[0079] Therefore, for system frequency safety constraints, different operating modes of liquid hydrogen superconducting co-melting energy storage need to be reasonably selected according to different types of system frequency safety events:

[0080] When the system frequency is lower than the rated value, the fuel cell participates in frequency modulation and performs positive frequency modulation, at this time,

[0081] The system frequency minimum point constraint in formula (2) is specifically:

[0082]

[0083] The system quasi-steady frequency constraint in formula (3) is:

[0084]

[0085] In the formula, is the gain coefficient of the fuel cell.

[0086] When the system frequency is higher than the rated frequency, the water electrolysis hydrogen production device participates in frequency modulation and performs negative frequency modulation, at this time,

[0087] The system frequency minimum point constraint in formula (2) is specifically:

[0088]

[0089] The system quasi-steady frequency constraint in formula (3) is:

[0090]

[0091] In the formula, is the gain coefficient of the water electrolysis hydrogen production device.

[0092] The above three constraints are derived from the complex analysis and derivation of a new power system that includes liquid hydrogen superconducting co-existing energy storage equipment. They can reflect the complex dynamic frequency regulation process of the system and greatly reduce the complexity while ensuring effectiveness.

[0093] In actual modeling, considering that the minimum frequency constraint of the above system has extremely high nonlinearity, the model solution is too complex. In order to reduce the difficulty of the solution, in one embodiment, the minimum frequency constraint of the system is reconstructed based on linearized frequency to solve the problem of high nonlinearity of the model.

[0094] This method introduces a linearized frequency bias:

[0095]

[0096] The primary frequency regulation power of the synchronous generator can be determined by the inverse Laplace transform. The approximate expression is:

[0097]

[0098] because The value is always less than The constraint on the lowest point of the system frequency can be rewritten as:

[0099]

[0100] Will The expression is for both sides By taking the derivative, we can see that:

[0101]

[0102] in:

[0103]

[0104] The derivative result shows that... Will follow As the system's minimum inertia coefficient increases, the constraint at the lowest system frequency point in equation (2) is reconstructed as follows:

[0105]

[0106] Therefore, the minimum frequency constraint of the system after linearization can be divided into two cases:

[0107] When the system frequency is lower than the rated value, the fuel cell participates in frequency regulation, and the constraint of the lowest system frequency point in equation (5) is reconstructed as follows:

[0108]

[0109] When the system frequency is higher than the rated frequency, the electrolytic water hydrogen production device participates in frequency modulation, and the minimum system frequency constraint in formula (7) is reconstructed as:

[0110]

[0111] In actual modeling, the working state of the unit is considered, and the following specific constraints are constructed to equivalently realize the above three safety constraints, that is, based on the above three safety constraints, the working state of the synchronous unit is combined to construct the synchronous generator constraint, the liquid hydrogen superconducting eutectic energy storage device constraint, the transformed system frequency minimum constraint and the transformed system quasi-steady frequency constraint which satisfy the above three safety constraints and are more simple and more consistent with actual operation, and in different system frequency states, the operating state of the liquid hydrogen superconductive eutectic energy storage device is selected according to the system frequency safety event and the corresponding constraint condition is constructed:

[0112] When the system frequency is lower than the rated value, the fuel cell in the liquid hydrogen superconducting eutectic energy storage device is put into operation for forward frequency modulation:

[0113] The synchronous generator constraint includes:

[0114]

[0115] In the formula: is the actual reserved capacity of the synchronous unit for adjusting the minimum system frequency, is the actual reserved capacity of the synchronous unit for adjusting the quasi-steady system frequency, is the synchronous unit power, is the maximum synchronous unit power;

[0116] The liquid hydrogen superconducting eutectic energy storage device constraint is the fuel cell device constraint, which includes:

[0117]

[0118] In the formula: is the actual reserved capacity of the fuel cell device for adjusting the minimum system frequency, is the actual reserved capacity of the fuel cell device for adjusting the quasi-steady system frequency, is the gain coefficient of the fuel cell, is the fuel cell device working power, is the maximum fuel cell device working power;

[0119] The transformed system frequency minimum constraint includes:

[0120]

[0121] The deformed system quasi-steady frequency constraint includes:

[0122]

[0123] When the system frequency is higher than the rated value, the electrolytic water hydrogen production device in the liquid hydrogen superconducting eutectic energy storage device is put into operation, and negative frequency modulation is performed:

[0124] The synchronous generator constraint includes:

[0125]

[0126] The liquid hydrogen superconducting eutectic energy storage device constraint for the electrolytic water hydrogen production device includes:

[0127]

[0128] In the formula: is the actual reserved capacity of the electrolytic water hydrogen production device for adjusting the system frequency minimum point, is the actual reserved capacity of the electrolytic water hydrogen production device for adjusting the system quasi-steady frequency, is the working power of the electrolytic water hydrogen production device, is the maximum working power of the electrolytic water hydrogen production device; is the gain coefficient of the fuel cell;

[0129] The deformed system frequency minimum point constraint includes:

[0130]

[0131] The deformed system quasi-steady frequency constraint includes:

[0132]

[0133] Based on the above, the system frequency safety constraint can be realized.

[0134] When the system frequency is lower than the rated value, the system frequency safety constraint can be formula (1), (5), (6), or formula (1), (17), (6) obtained by reconfiguring on the basis of formula (1), (5), (6), or formula (19), (20), (21), (22) obtained by further considering the state of the traditional unit on the basis of formula (1), (17), (6), whether it is formula (1), (17), (6) or formula (19), (20), (21), (22), it is within the scope constrained by formula (1), (5), (6).

[0135] When the system frequency is higher than the rated value, the system frequency safety constraint can be formula (1), (7), (8), or formula (1), (7), (8) after reconstruction, or formula (23), (24), (25), (26) further considering the state of the traditional unit based on formula (1), (18), (8). Whether it is formula (1), (18), (8) or formula (23), (24), (25), (26), it is within the scope of formula (1), (7), (8).

[0136] In addition to the above-mentioned system frequency safety constraint, the remaining conventional unit combination constraints can also be added, such as system power balance constraint, system spinning reserve constraint, unit output upper and lower limit constraint, liquid hydrogen superconducting eutectic energy storage device upper and lower limit constraint, synchronous unit minimum start-stop time constraint, and synchronous unit power ramp rate constraint.

[0137] (1) System power balance constraint

[0138] System power balance refers to the output of traditional synchronous units, wind turbine generators, and liquid hydrogen superconducting eutectic energy storage devices in the system must equal the sum of system load and network loss. In the case of not considering system network loss, the system power balance constraint is:

[0139]

[0140] Wherein: P is the system load.

[0141] (2) System spinning reserve constraint

[0142] System spinning reserve is an important measure to ensure reliable power supply. It not only provides adjustment capacity to make up for load deviation caused by inaccurate load prediction, but also quickly transfers load to other units in the system when a large unit fails, preventing serious load shortage and causing system frequency to drop sharply, threatening system safety. The system spinning reserve constraint is:

[0143]

[0144] Wherein: δ l0ad is the spinning reserve coefficient, is the maximum power generation of the synchronous generator set, is the minimum power generation of the synchronous generator set.

[0145] (3) Unit output upper and lower limit constraint

[0146] The output of the unit must be greater than or equal to its allowed maximum output, and less than or equal to its allowed minimum output to ensure the safe and stable operation of the unit:

[0147]

[0148] (4) Upper and lower limits of constraints on liquid hydrogen superconducting co-existing energy storage devices

[0149] To ensure the safe and stable operation of the liquid hydrogen superconducting syngas energy storage device and extend its service life, the operating power of the electro-hydrogen energy conversion device must be within the allowable range of the equipment and meet the following constraints:

[0150]

[0151] in: This represents the maximum power generation of the fuel cell device. Minimum power generation for fuel cell devices

[0152] quantity, This represents the maximum power generation of the water electrolysis hydrogen production unit. This is the minimum power generation capacity for the water-to-hydrogen production device.

[0153] Meanwhile, the operation of the electro-hydrogen energy conversion equipment will directly lead to changes in the mass of liquid hydrogen inside the Dewar. As the direct cooling medium for the superconducting magnetic energy storage device, liquid hydrogen should always be kept within a safe range to fully absorb the operating losses of the superconducting magnetic energy storage device, ensure a low-temperature environment, and prevent the superconducting magnet from losing its quench.

[0154] The mass of hydrogen produced by the water electrolysis hydrogen production device is:

[0155]

[0156] The mass of liquid hydrogen consumed by the fuel cell device is:

[0157]

[0158] in: For the hydrogen production of the water electrolysis hydrogen production unit, η EL / FC To improve the working efficiency of the electricity-hydrogen energy conversion device. HHV represents the operating power of the water electrolysis hydrogen production device and the fuel cell device, HHV represents the higher calorific value of hydrogen, and Δk represents the length of the cycle time window.

[0159] The mass of liquid hydrogen inside the liquid hydrogen dewar is:

[0160]

[0161] in: Total mass of liquid hydrogen in Dewar

[0162] At this point, the mass of liquid hydrogen inside the Dewar should meet the following constraints:

[0163]

[0164] wherein: is the minimum liquid hydrogen mass in the Dewar, is the maximum liquid hydrogen mass in the Dewar.

[0165] (5) Minimum start-up and shut-down time constraint of synchronous units

[0166] Due to the technical requirements in the synchronous units, once the unit is started (stopped), it must be operated for a period of time and cannot be immediately stopped (started), therefore, when planning the start-up and shut-down of the synchronous units, the minimum start-up and shut-down time constraint should be met:

[0167]

[0168] wherein: is the number of continuous start-up time periods of the synchronous units, is the number of continuous shut-down time periods of the synchronous units, is the minimum operation time of the synchronous units, is the minimum shut-down time of the synchronous units.

[0169] (6) Power ramp rate constraint of synchronous units

[0170] The ramp constraint rate refers to the output that can be increased or decreased by the synchronous units in each time period, wherein the output that can be increased by the unit per minute is referred to as the uphill rate, and vice versa, which is referred to as the downhill rate, and the power ramp rate constraint of the synchronous units is:

[0171]

[0172] wherein: is the maximum uphill ramp rate of the synchronous units, is the maximum downhill ramp rate of the synchronous units.

[0173] The objective function of the frequency security constrained unit commitment model of the liquid hydrogen-containing superconducting co-melting energy storage primary frequency regulation is to minimize the system traditional unit power generation cost, start-up and shut-down cost, electric-hydrogen energy conversion equipment operation cost and wind curtailment loss cost on the premise of meeting the system load, reserve, unit operation limit, frequency safety limit and other constraints, and the expression of the objective function is:

[0174]

[0175] wherein: in the formula: are the power generation cost, start-up cost and shut-down cost of the synchronous units, respectively, is the working power of the fuel cell device, is the working power of the water electrolysis hydrogen production device, c FC is the unit working cost of the fuel cell device, cEL c is the unit work cost of the water electrolysis hydrogen production device cur c is the unit penalty cost of abandoning renewable energy power, c is the renewable energy abandonment rate, c is the renewable energy electric power, subscript w is the wth renewable energy.

[0176] In the electricity market, the generation cost and the synchronous unit generation capacity have a quadratic function relationship:

[0177]

[0178] wherein a, b, and c are constant coefficients, c is the synchronous unit generation power, and the quadratic function can be linearized by using a segmented function:

[0179]

[0180] Step S3: solving the liquid hydrogen superconducting co-melting energy storage assisted new type power system primary frequency modulation unit combination model, and outputting the unit combination control strategy of each cycle.

[0181] Taking the power system framework in Figure 2 as an example, the above frequency modulation method is verified, and the following three different frequency modulation methods are compared:

[0182] Case1: traditional unit combination model without considering the effect of energy storage;

[0183] Case2: unit combination model considering lithium battery frequency modulation. The lithium battery is installed at node 4 and node 5, and the maximum capacity is 15MW, the inertia coefficient is 3s, and the droop control coefficient is 15. The unit combination state of Case2 is the same as that of Case1, and only when the system power disturbance occurs, the lithium battery participates in the charging and discharging to assist the traditional synchronous unit to adjust the system frequency change;

[0184] Case3: the frequency modulation method of the liquid hydrogen superconducting co-melting energy storage assisted primary frequency modulation proposed in the application.

[0185] Table 1 is the parameter of the traditional synchronous unit, and Table 2 is the parameter of the liquid hydrogen superconducting co-melting energy storage.

[0186] Table 1: Parameters of traditional synchronous units

[0187]

[0188] Table 2: Parameters of liquid hydrogen superconducting co-melting energy storage

[0189]

[0190] The simulation results of the power system frequency modulation safety index in the whole period are as followsFigures 3 to 8 As shown in FIG. 6, Figures 3 to 5 The simulation result of the positive frequency modulation safety index of the system is shown in FIG. 6, Figures 6 to 8 The simulation result of the negative frequency modulation safety index of the system is shown in FIG. 6. In Case 1 and Case 2, the maximum frequency change rate, the maximum frequency deviation and the quasi-steady-state frequency deviation of the system all exceed the threshold to different degrees, which is caused by the large load and the small reserved capacity of the synchronous generator for frequency modulation, and the addition of the energy storage device such as lithium battery can obviously improve the occurrence of the safety index exceeding the threshold. In Case 3, the maximum frequency change rate, the maximum frequency deviation and the quasi-steady-state frequency deviation of the system are all within the threshold range, which is because, compared with the lithium battery, the liquid hydrogen superconducting co-melting energy storage device can cooperate with the traditional synchronous generator, the fuel cell device, the hydrogen production device by electrolysis of water and the superconducting magnetic energy storage device to change the output of each component of the system by reasonably responding to the load change, so as to ensure that the frequency safety index of the system is always within the threshold range. In comparison, the frequency modulation effect of the frequency modulation method of the liquid hydrogen superconducting co-melting energy storage assisted primary frequency modulation proposed in the application is the best.

[0191] Embodiment 2

[0192] The application also relates to an electronic device comprising a memory and a processor, the memory storing a computer program, and the processor implementing the steps of the above method when executing the computer program.

[0193] The electronic device can be a desktop computer, a notebook computer, a palm computer, a cloud server and the like. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components and the like. The memory can be used to store computer programs and / or modules, and the processor can implement various functions of the electronic device by running or executing the computer programs and / or modules stored in the memory, and calling data stored in the memory.

[0194] Embodiment 3

[0195] The application also relates to a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the steps of the above method.

[0196] In particular, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one disk storage device, a flash memory device, or other volatile solid-state memory device.

[0197] Embodiment 4

[0198] The embodiment of the present application provides a computer program product or computer program, the computer program product or computer program comprising computer instructions stored in a computer readable storage medium. The processor of the computer equipment reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions, so that the computer equipment executes the steps of the method of the above-mentioned embodiment of the present application.

[0199] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered that it is within the scope of the present application. It should be noted that the "in an embodiment of the present application", "for example", "such as" and the like of the present application are intended to illustrate the present application, and are not used to limit the present application.

[0200] The above-mentioned embodiments only express several embodiments of the present application, the description is more specific and detailed, but it should not be understood as limiting the scope of the application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application.

Claims

1. A method for unit commitment of a liquid hydrogen superconducting co-melting energy storage assisted novel power system primary frequency modulation, characterized in that, The method comprises the following steps: acquiring data of a new power system comprising traditional synchronous units, renewable energy generating units and liquid hydrogen superconducting co-melting energy storage devices; establishing a primary frequency modulation unit combination model of the liquid hydrogen superconducting co-melting energy storage assisted new power system, the model comprising an objective function and constraint conditions, the objective function being to minimize the total economic cost of the system, and the constraint conditions being to make the operation of the system meet the system maximum frequency change rate constraint, the system frequency minimum point constraint and the system quasi-steady frequency constraint on the basis of meeting the traditional unit combination constraint conditions; The system maximum frequency change rate constraint includes: ; The system frequency nadir constraint includes: ; The system quasi-steady frequency constraint includes: ; In the formula: subscript k , t , i , j They represent the first k Each frequency modulation cycle, within the frequency modulation cycle t Time, Number i The first synchronous generator unit, the first j A liquid hydrogen superconducting co-existing energy storage device; The first frequency regulation for power systems k Power disturbance at t=0s within a cycle; The system's rated frequency; For the synchronous generator unit switch binary variable, take This indicates that the synchronous generator unit is in operation; a value of 0 indicates that the synchronous generator unit is not in operation. , These are the inertia coefficients of the synchronous generator and the superconducting magnetic energy storage device, respectively. This represents the system's maximum rate of frequency change. This refers to the primary frequency regulation power of the synchronous generator unit; These are the gain coefficients for the synchronous generator unit and the liquid hydrogen superconducting co-existing energy storage device, respectively. The system damping coefficient; The threshold for the lowest frequency point; The quasi-steady-state frequency threshold of the system; solving the primary frequency modulation unit combination model of the liquid hydrogen superconducting co-melting energy storage assisted new power system to output the unit combination control strategy of each cycle; the constraint conditions that make the operation of the system meet the system maximum frequency change rate constraint, the system frequency minimum point constraint and the system quasi-steady frequency constraint can be reconstructed into the synchronous generator constraint, the liquid hydrogen superconducting co-melting energy storage device constraint, the transformed system frequency minimum point constraint and the transformed system quasi-steady frequency constraint in the unit combination model; before the primary frequency modulation unit combination model is established, the current system frequency is acquired, and the operating state of the liquid hydrogen superconducting co-melting energy storage device is selected according to the current system frequency and the corresponding constraint condition is constructed; when the system frequency is lower than the rated value, the fuel cell in the liquid hydrogen superconducting co-melting energy storage device is put into operation to perform positive frequency modulation; the synchronous generator constraint comprises: In the formula: This is the actual reserved capacity for synchronous generators to adjust the lowest point of the system frequency. This is the actual reserved capacity for synchronous generators to adjust the quasi-steady-state frequency of the system. For synchronous generator unit power generation, This represents the maximum generating capacity of the synchronous generator unit. The primary frequency regulation power of the synchronous generator unit after linearization. Approximate value, This represents the minimum total inertia coefficient of the system. The response time constant of the synchronous generator unit; the liquid hydrogen superconducting co-melting energy storage device constraint is the fuel cell device constraint, comprising: wherein: is the actual reserve capacity of the fuel cell device for adjusting the system frequency minimum, is the actual reserve capacity of the fuel cell device for adjusting the system quasi-steady frequency, is the gain coefficient of the fuel cell, is the operating power of the fuel cell device, is the maximum operating power of the fuel cell device; the transformed system frequency minimum point constraint comprises: the transformed system quasi-steady frequency constraint comprises: 。 2. The method of claim 1, wherein, when the system frequency is higher than the rated value, the water electrolysis hydrogen production device in the liquid hydrogen superconducting co-melting energy storage device is put into operation to perform negative frequency modulation; the synchronous generator constraint comprises: the liquid hydrogen superconducting co-melting energy storage device constraint is the water electrolysis hydrogen production device constraint, comprising: In the formula: is the actual reserved capacity of the water electrolysis hydrogen production device for adjusting the minimum point of the system frequency, is the actual reserved capacity of the water electrolysis hydrogen production device for adjusting the quasi-steady frequency of the system, is the working power of the water electrolysis hydrogen production device, is the maximum working power of the water electrolysis hydrogen production device; is the gain coefficient of the fuel cell; the transformed system frequency minimum point constraint comprises: the transformed system quasi-steady frequency constraint comprises: 。 3. The method of claim 1, wherein, the objective function is: wherein: , , are the generation cost, the start-up cost, the shut-down cost of the synchronous units, respectively, is the fuel cell device work power, is the water electrolysis hydrogen production device work power, is the fuel cell device unit work cost, is the water electrolysis hydrogen production device unit work cost, is the power unit penalty cost for discarding renewable energy, is the renewable energy discarding rate, is the renewable energy electric power discarded, subscript w is the wth renewable energy generator.

4. The method of claim 1, wherein, the constraint conditions further comprise: a system power balance constraint, a system rotating reserve constraint, a unit output upper and lower limit constraint, a liquid hydrogen superconducting co-melting energy storage device power upper and lower limit constraint, a synchronous unit minimum start-stop time constraint and a synchronous unit power ramping rate constraint.

5. The method of claim 1, wherein, Inertial coefficient of a superconducting magnetic energy storage device Rated power of a superconducting magnetic energy storage device And system maximum frequency change rate Satisfies: 。 6.An electronic device comprising a memory and a processor, the memory storing a computer program, wherein, The processor executes the computer program to realize the steps of the method of any one of claims 1 to 5.

7. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the method of any one of claims 1 to 5.

8. A computer program product comprising computer programs or instructions, characterized in that, The computer program or instructions are executed by the processor to realize the steps of the method of any one of claims 1 to 5.

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