High-proportion new energy power system dynamic adjustment demand quantitative evaluation method

Abstract

The invention provides a high-proportion new energy power system dynamic regulation demand quantitative evaluation method. The high-proportion new energy power system dynamic regulation demand quantitative evaluation method comprises the following steps: step (1), constructing a frequency response model of a high-proportion new energy power system; step (2), constructing a power system frequency stability demand evaluation model; and step (3), processing the maximum frequency deviation constraint. According to the high-proportion new energy power system dynamic regulation demand quantitative evaluation method provided by the invention, nonlinear constraints such as a frequency modulation dead zone are considered, a system frequency response analysis model under high-proportion new energy access is constructed, and a frequency response result is obtained through solving; and a high-proportion new energy power system dynamic adjustment demand quantitative evaluation model is established, and system adjustment demand evaluation considering multi-resource collaborative participation is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy grid-connected operation and control, and in particular relates to a method for quantitatively evaluating dynamic regulation demand of a high-proportion new energy power system. Background Art

[0002] The 9th meeting of the Central Financial and Economic Commission proposed to build a new power system, which pointed out the scientific direction for the development of energy and power systems in the new era. New energy units, mainly large-scale photovoltaics, are connected to the power system on a large scale through converters. New energy units without any control strategy attached to the converters cannot provide any inertia support for the power system, resulting in the continuous improvement of the system's power electronics level and a sharp decline in the proportion of synchronous generators. The rotational inertia in the system is seriously insufficient, posing a huge threat to the system frequency stability. The system dynamic adjustment demand has thus become a key parameter for the inertia configuration of future power systems. At present, there are few studies on the evaluation of system dynamic adjustment demand. Foreign studies mainly use system frequency deviation and frequency change rate (RoCoF) as the main constraints for the evaluation of minimum inertia dynamic adjustment demand, and consider the role of fast frequency response (FFR). However, existing domestic research is mainly aimed at the models of the two key parameters of system frequency deviation and RoCoF under system disturbance. Among them, RoCoF can be directly obtained through the rotor motion equation, while the system frequency deviation is more complicated to obtain. For example, some studies divide the numerical calculation method of the minimum frequency value into three models: climbing model, dynamic response model and response time model. Existing studies have mainly established a frequency response model combined with a group optimization algorithm to conduct a large-scale search to obtain the minimum inertia of the system in order to obtain the maximum frequency deviation of the system's dynamic regulation needs. However, the existing methods of obtaining the maximum frequency deviation through analytical expressions do not consider the situation where new energy units participate in inertia response and primary frequency regulation. Therefore, this patent proposes a quantitative assessment method for the dynamic regulation demand of a high-proportion new energy power system, taking into account nonlinear constraints such as frequency regulation dead zones, constructing an analytical model of the system frequency response under a high proportion of new energy access and solving it to obtain the frequency response result, and then establishing a quantitative assessment model for the dynamic regulation demand of a high-proportion new energy power system, to achieve system regulation demand assessment that considers the collaborative participation of multiple resources. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a method for quantitatively evaluating the dynamic regulation demand of a high-proportion renewable energy power system, taking into account nonlinear constraints such as frequency regulation dead zones, constructs an analytical model of system frequency response under high-proportion renewable energy access and solves it to obtain frequency response results, and then establishes a quantitative evaluation model for the dynamic regulation demand of a high-proportion renewable energy power system, so as to realize the system regulation demand evaluation considering the collaborative participation of multiple resources.

[0004] The present invention specifically provides a method for quantitatively evaluating the dynamic regulation demand of a high-proportion new energy power system, and the method for quantitatively evaluating the dynamic regulation demand of a high-proportion new energy power system comprises the following steps:

[0005] Step (1): construct a frequency response model of a high-proportion renewable energy power system;

[0006] Step (2): construct a power system frequency stability demand assessment model;

[0007] Step (3): Processing of the maximum frequency deviation constraint.

[0008] Furthermore, in step (1), a frequency response model of a high-proportion renewable energy power system is constructed, specifically including a frequency response model of a thermal power unit, a renewable energy grid-connected frequency response model considering virtual synchronous machine control, and a renewable energy system frequency response aggregation model considering the impact of a primary frequency regulation dead zone.

[0009] Furthermore, the specific method for constructing the frequency response model of the thermal power unit is:

[0010] The primary frequency regulation power linear growth model is used to simulate the frequency regulation process of thermal power units, and its expression is:

[0011]

[0012] In the formula Provide primary frequency regulation power for a single thermal power unit, MW; is the primary frequency regulation capacity of a single thermal power unit, MW; T G With t d They are respectively the time when the primary frequency regulation capacity of the synchronous unit is fully put into use and the primary frequency regulation dead zone time of the thermal power unit, s.

[0013] Furthermore, the specific method for constructing a new energy grid-connected frequency response model considering virtual synchronous machine control is as follows:

[0014] Since new energy and energy storage units cannot participate in the inertia response and frequency regulation of the power system without adding any control measures to the converter, the frequency stability of the highly electronic power system is greatly reduced when disturbances occur. New energy power generation devices and energy storage units using virtual synchronization technology can provide inertial response and primary frequency regulation services for the system, which can make up for the defects of the highly electronic power system in frequency stability. This paper considers adding virtual inertia control based on frequency change rate and primary frequency regulation control based on frequency deviation to the inverters of new energy generators and energy storage devices. After adding the above control links to the inverter, the instantaneous support power of the virtual inertia provided by all new energy generators and energy storage devices in area k is:

[0015]

[0016] Where: is the total power of all virtual synchronous machines participating in the inertial response in area k, MW; is the inertia time constant of all renewable energy generating units and energy storage devices in region k, MW·s; is the frequency deviation of the leading unit in region k, Hz; f N is the system reference frequency, Hz.

[0017] At this time, the total inertia of area k is H k It can be expressed as:

[0018]

[0019] Where: is the inertia time constant of all thermal power units in area k, s. After adding the above control links to the inverter, the primary frequency modulation power provided by a single VSM is:

[0020]

[0021] Where: Primary frequency regulation power provided for a single VSM, MW; is the primary frequency regulation capacity of a single VSM, MW; Δf d is the dead zone frequency, Hz; Adjust the power per unit for a single VSM unit.

[0022] Furthermore, the specific method for constructing a frequency response aggregation model of a new energy system considering the influence of the primary frequency modulation dead zone is as follows:

[0023] During the normal operation of the system, the system frequency is not completely constant. As the load power and renewable energy output fluctuate, the rotor speed of the generator set also changes slightly, resulting in changes in the system frequency. If the influence of the VSM primary frequency regulation dead zone is completely ignored: First, under the primary frequency regulation without dead zone restrictions, the frequency fluctuations of the power system during normal operation will cause the VSM primary frequency regulation to frequently operate; secondly, without considering the frequency regulation dead zone, the evaluation results of indicators such as the actual frequency deviation of the system may be too optimistic, which will affect the configuration parameters of the relay protection equipment, prolong the action time of the safety protection measures, and is not conducive to improving the stability of the power system. This paper considers the influence of the primary frequency regulation dead zone of thermal power units and VSM at the same time. The total power of the primary frequency regulation in area k is:

[0024]

[0025] Where: is the total primary frequency modulation power in area k in MW; k G and kVSM are the total number of single thermal power units and VSM in area k; ΔP Gi (t) and ΔP VSMi (t) are the primary frequency regulation powers provided by the i-th thermal power unit and VSM in region k, MW.

[0026] Before the system frequency deviation is greater than the dead zone frequency, all primary frequency regulation units in area k are not started. After the system frequency deviation is greater than the dead zone frequency, the dead zone frequency is brought into the synchronous unit and VSM primary frequency regulation model. At this time, the sum of the primary frequency regulation power of all synchronous units and VSM units in area k can be expressed as:

[0027]

[0028] Where: is the overall coefficient of all synchronous units in region k, MW / s; is the overall frequency modulation coefficient of all VSMs in area k, MW / Hz; n G is the number of all synchronous units in area k.

[0029] Furthermore, the specific method for constructing the power system frequency stability demand assessment model in step (2) is:

[0030] The optimization objective of establishing the regional k-frequency stability demand assessment model is:

[0031]

[0032] in:

[0033]

[0034] Where: Optimize the objective function for the regional k-frequency stability demand assessment model; and They are the minimum inertia requirement optimization objective function of area k and the primary frequency modulation power optimization objective function of area k respectively; is the minimum inertia required for zone k, MW / s.

[0035] The following constraints are mainly considered:

[0036] (1) Regional overall inertia level constraint

[0037] The minimum inertia of area k must be maintained between the maximum inertia that all dispatchable units can provide when the area is operating normally and the minimum inertia that can be provided by the dispatchable units when a disturbance occurs and there is no virtual inertia, which can be expressed as:

[0038]

[0039] Where: is the lower limit of the overall inertia time constant of all operating synchronous units (including VSM) in area k, s; The upper limit of the total time constant that can be provided by all synchronous machines (including VSM) in area k that can provide inertia, s.

[0040] (2) Frequency stability constraints

[0041] The frequency stability constraint is a constraint set to ensure that the system frequency always runs within the system's allowable range. This article mainly considers the RoCoF constraint and the maximum frequency deviation constraint.

[0042] ①RoCoF constraints

[0043] The maximum frequency change rate in area k generally occurs at the moment when the disturbance occurs. Under the premise of ensuring that the safety protection measures of the power system do not act, the maximum frequency change rate in area k must be less than the maximum safe frequency change rate specified by the system, which can be expressed as:

[0044]

[0045] Where: and They are respectively the maximum frequency change rate of the representative unit in area k and the upper limit of the maximum frequency change rate set for the entire system to ensure safe and stable operation, Hz / s.

[0046] Since the frequency modulation in the area was not started immediately after the disturbance, this constraint can be transformed into the following form:

[0047]

[0048] Where: is the size of the disturbance assigned to region k, MW.

[0049] ②Maximum frequency deviation constraint

[0050] The frequency deviation of region k should always be kept within the maximum frequency deviation allowed by the system:

[0051]

[0052] Where: and are the maximum frequency deviation of region k and the maximum frequency deviation allowed by the system, Hz respectively.

[0053] (3) Quasi-steady-state frequency deviation constraint

[0054] After one frequency modulation, the frequency of region k reaches a quasi-steady state, which can be expressed as:

[0055]

[0056] Where: and are the quasi-steady-state frequency deviation of the representative unit in region k at the end of a frequency modulation and the maximum quasi-steady-state frequency deviation upper limit set for the entire system to ensure safe and stable operation, Hz; D k Damping size in region k, MW / Hz

[0058] (4) Power capacity limitation

[0059] For thermal power units and VSM units, the primary frequency regulation power will be affected by the capacity of their own backup power supply. Under the limitation of the adjustable capacity of the power supply, the primary frequency regulation output limit expression of thermal power units and VSM units is as follows:

[0060]

[0061] Where: and are the power output after primary frequency regulation and amplitude limiting of the power supply of the thermal power unit and the VSM unit respectively; R Gi,min With R VSMi,min They are the power limit reduction limits of various power supplies; R Gi,max With R VSMi,max They are respectively the power limit upward adjustment limits for each type of power supply.

[0062] Furthermore, the specific method for processing the maximum frequency deviation constraint in step (3) is:

[0063] In the above constraint formula, after adding a frequency modulation dead zone, the rotor motion equation becomes a piecewise form, which makes this constraint a piecewise nonlinear constraint. It is necessary to discuss it piecewise on the original basis and solve the equation according to the critical conditions of the dividing point.

[0064] (31) Before the center frequency of region k reaches the frequency dead zone, all units have not acted on the primary frequency regulation. At this time, the rotor motion equation of region k can be expressed as:

[0065]

[0066] It can be obtained that the central frequency deviation expression of region n before a frequency modulation action is:

[0067]

[0068] When the frequency in region k reaches the dead zone frequency, the frequency deviation of the critical point can be obtained:

[0069]

[0070] (32) After the center frequency of region k reaches the frequency dead zone, assuming that all regions have sufficient frequency regulation capacity, the maximum frequency deviation of each region can be reached before the thermal power unit reaches the maximum frequency regulation power. Substituting into the rotor motion equation, we can get:

[0071]

[0072] It can be obtained that the central frequency deviation expression of region k after one frequency modulation action is:

[0073]

[0074] in: C is an arbitrary constant.

[0075] When the frequency modulation in region k starts, substituting equation (18) as the initial condition into equation (19) yields:

[0076]

[0077] According to the obtained frequency deviation expression, it can be seen that before reaching the dead time, due to Causes frequency deviation And as time goes by Will continue to increase; after reaching the dead time, due to And as time goes by, Increases exponentially, and finally This change pattern is consistent with the frequency change of the system under the action of primary frequency modulation.

[0078] make The time when region k reaches the maximum frequency deviation can be obtained

[0079]

[0080] Substituting formula (21) into formula (20), we can obtain:

[0081]

[0082] In formula (22), H k and Separation, we can get:

[0083]

[0084] Finally, the separated formula (23) is substituted into the constraint formula to obtain:

[0085]

[0086] After the above processing, the original nonlinear inequality constraints have been transformed into linear inequality constraints, which greatly increases the complexity of model solution and improves computational efficiency.

[0087] Compared with the prior art, the beneficial effects are:

[0088] 1. The present invention proposes a method for quantitatively evaluating the dynamic regulation demand of a high-proportion renewable energy power system. The method considers nonlinear constraints such as frequency regulation dead zone, constructs an analytical model of system frequency response under high-proportion renewable energy access, and solves the model to obtain the frequency response result. Then, a quantitative evaluation model for dynamic regulation demand of a high-proportion renewable energy power system is established to realize the evaluation of system regulation demand considering the collaborative participation of multiple resources.

[0089] 2. The present invention proposes a quantitative evaluation method for the dynamic regulation demand of a high-proportion renewable energy power system, clarifies the regulation demand of the system under the high-proportion renewable energy access, and provides a theoretical basis for the formulation of frequency regulation control schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 It is a schematic diagram of a system frequency response model when VSM participates in inertia response, primary frequency modulation, and dead zone influence in an embodiment of the present invention. DETAILED DESCRIPTION

[0091] The specific implementation method of a method for quantitatively evaluating dynamic regulation demand of a high-proportion new energy power system of the present invention is described in detail below with reference to the accompanying drawings.

[0092] like Figure 1 As shown, the method for quantitatively evaluating the dynamic regulation demand of a high-proportion new energy power system of the present invention comprises the following steps:

[0093] Step (1): construct a frequency response model of a high-proportion renewable energy power system;

[0094] Step (2): construct a power system frequency stability demand assessment model;

[0095] Step (3): Processing of the maximum frequency deviation constraint.

[0096] In step (1), a frequency response model of a high-proportion renewable energy power system is constructed, specifically including a frequency response model of a thermal power unit, a renewable energy grid-connected frequency response model considering virtual synchronous machine control, and a renewable energy system frequency response aggregation model considering the impact of a primary frequency regulation dead zone.

[0097] The specific method for constructing the frequency response model of thermal power units is:

[0098] Thermal power units are the main source of frequency adjustment in the power system. Their adjustment space and response speed will affect the dynamic recovery of system frequency. This paper uses a linear growth model of primary frequency regulation power to simulate the frequency regulation process of thermal power units, and its expression is:

[0099]

[0100] In the formula Provide primary frequency regulation power for a single thermal power unit, MW; is the primary frequency regulation capacity of a single thermal power unit, MW; T G With t d They are respectively the time when the primary frequency regulation capacity of the synchronous unit is fully put into use and the primary frequency regulation dead zone time of the thermal power unit, s.

[0101] The specific method for constructing a new energy grid-connected frequency response model considering virtual synchronous machine control is:

[0102] Since new energy and energy storage units cannot participate in the inertia response and frequency regulation of the power system without adding any control measures to the converter, the frequency stability of the highly electronic power system is greatly reduced when disturbances occur. New energy power generation devices and energy storage units using virtual synchronization technology can provide inertial response and primary frequency regulation services for the system, which can make up for the defects of the highly electronic power system in frequency stability. This paper considers adding virtual inertia control based on frequency change rate and primary frequency regulation control based on frequency deviation to the inverters of new energy generators and energy storage devices. After adding the above control links to the inverter, the instantaneous support power of the virtual inertia provided by all new energy generators and energy storage devices in area k is:

[0103]

[0104] Where: is the total power of all virtual synchronous machines participating in the inertial response in area k, MW; is the inertia time constant of all renewable energy generating units and energy storage devices in region k, MW·s; is the frequency deviation of the leading unit in region k, Hz; f N is the system reference frequency, Hz.

[0105] At this time, the total inertia of area k is H k It can be expressed as:

[0106]

[0107] Where: is the inertia time constant of all thermal power units in area k, s. After adding the above control links to the inverter, the primary frequency modulation power provided by a single VSM is:

[0108]

[0109] Where: Primary frequency regulation power provided for a single VSM, MW; is the primary frequency regulation capacity of a single VSM, MW; Δf d is the dead zone frequency, Hz; Adjust the power per unit for a single VSM unit.

[0110] The specific method for constructing a frequency response aggregation model of a new energy system considering the impact of the primary frequency modulation dead zone is as follows:

[0111] During the normal operation of the system, the system frequency is not completely constant. As the load power and renewable energy output fluctuate, the rotor speed of the generator set also changes slightly, resulting in changes in the system frequency. If the influence of the VSM primary frequency regulation dead zone is completely ignored: First, under the primary frequency regulation without dead zone restrictions, the frequency fluctuations of the power system during normal operation will cause the VSM primary frequency regulation to frequently operate; secondly, without considering the frequency regulation dead zone, the evaluation results of indicators such as the actual frequency deviation of the system may be too optimistic, which will affect the configuration parameters of the relay protection equipment, prolong the action time of the safety protection measures, and is not conducive to improving the stability of the power system. This paper considers the influence of the primary frequency regulation dead zone of thermal power units and VSM at the same time. The total power of the primary frequency regulation in area k is:

[0112]

[0113] Where: is the total primary frequency modulation power in area k in MW; k G and k VSM are the total number of single thermal power units and VSM in area k; ΔP Gi (t) and ΔP VSMi (t) are the primary frequency regulation powers provided by the i-th thermal power unit and VSM in region k, MW.

[0114] Before the system frequency deviation is greater than the dead zone frequency, all primary frequency regulation units in area k are not started. After the system frequency deviation is greater than the dead zone frequency, the dead zone frequency is brought into the synchronous unit and VSM primary frequency regulation model. At this time, the sum of the primary frequency regulation power of all synchronous units and VSM units in area k can be expressed as:

[0115]

[0116] Where: is the overall coefficient of all synchronous units in region k, MW / s; is the overall frequency modulation coefficient of all VSMs in area k, MW / Hz; n G is the number of all synchronous units in area k.

[0117] The system frequency response model considering VSM's participation in inertia response, primary frequency modulation, and dead zone is as follows: Figure 1 shown.

[0118] The specific method for constructing the power system frequency stability demand assessment model in step (2) is:

[0119] The optimization objective of establishing the regional k-frequency stability demand assessment model is:

[0120]

[0121] in:

[0122]

[0123] Where: Optimize the objective function for the regional k-frequency stability demand assessment model; and They are the minimum inertia requirement optimization objective function of area k and the primary frequency modulation power optimization objective function of area k respectively; is the minimum inertia required for zone k, MW / s.

[0124] The following constraints are mainly considered:

[0125] (1) Regional overall inertia level constraint

[0126] The minimum inertia of area k must be maintained between the maximum inertia that all dispatchable units can provide when the area is operating normally and the minimum inertia that can be provided by the dispatchable units when a disturbance occurs and there is no virtual inertia, which can be expressed as:

[0127]

[0128] Where: is the lower limit of the overall inertia time constant of all operating synchronous units (including VSM) in area k, s; The upper limit of the total time constant that can be provided by all synchronous machines (including VSM) in area k that can provide inertia, s.

[0129] (2) Frequency stability constraints

[0130] The frequency stability constraint is a constraint set to ensure that the system frequency always runs within the system's allowable range. This article mainly considers the RoCoF constraint and the maximum frequency deviation constraint.

[0131] ①RoCoF constraints

[0132] The maximum frequency change rate in area k generally occurs at the moment when the disturbance occurs. Under the premise of ensuring that the safety protection measures of the power system do not act, the maximum frequency change rate in area k must be less than the maximum safe frequency change rate specified by the system, which can be expressed as:

[0133]

[0134] Where: and They are respectively the maximum frequency change rate of the representative unit in area k and the upper limit of the maximum frequency change rate set for the entire system to ensure safe and stable operation, Hz / s.

[0135] Since the frequency modulation in the area was not started immediately after the disturbance, this constraint can be transformed into the following form:

[0136]

[0137] Where: is the size of the disturbance assigned to region k, MW.

[0138] ②Maximum frequency deviation constraint

[0139] The frequency deviation of region k should always be kept within the maximum frequency deviation allowed by the system:

[0140]

[0141] Where: and are the maximum frequency deviation of region k and the maximum frequency deviation allowed by the system, Hz respectively.

[0142] (3) Quasi-steady-state frequency deviation constraint

[0143] After one frequency modulation, the frequency of region k reaches a quasi-steady state, which can be expressed as:

[0144]

[0145] Where: and are the quasi-steady-state frequency deviation of the representative unit in region k at the end of a frequency modulation and the maximum quasi-steady-state frequency deviation upper limit set for the entire system to ensure safe and stable operation, Hz; D k Damping magnitude in region k, MW / Hz.

[0147] (4) Power capacity limitation

[0148] For thermal power units and VSM units, the primary frequency regulation power will be affected by the capacity of their own backup power supply. Under the limitation of the adjustable capacity of the power supply, the primary frequency regulation output limit expression of thermal power units and VSM units is as follows:

[0149]

[0150] Where: and are the power output after primary frequency regulation and amplitude limiting of the power supply of the thermal power unit and the VSM unit respectively; R Gi,min With R VSMi,min They are the power limit reduction limits of various power supplies; R Gi,max With R VSMi,max They are respectively the power limit upward adjustment limits for each type of power supply.

[0151] The specific method for processing the maximum frequency deviation constraint in step (3) is:

[0152] In the above constraint formula, after adding a frequency modulation dead zone, the rotor motion equation becomes a piecewise form, which makes this constraint a piecewise nonlinear constraint. It is necessary to discuss it piecewise on the original basis and solve the equation according to the critical conditions of the dividing point.

[0153] (31) Before the center frequency of region k reaches the frequency dead zone, all units have not acted on the primary frequency regulation. At this time, the rotor motion equation of region k can be expressed as:

[0154]

[0155] It can be obtained that the central frequency deviation expression of region n before a frequency modulation action is:

[0156]

[0157] When the frequency in region k reaches the dead zone frequency, the frequency deviation of the critical point can be obtained:

[0158]

[0159] (32) After the center frequency of region k reaches the frequency dead zone, assuming that all regions have sufficient frequency regulation capacity, the maximum frequency deviation of each region can be reached before the thermal power unit reaches the maximum frequency regulation power. Substituting into the rotor motion equation, we can get:

[0160]

[0161] It can be obtained that the central frequency deviation expression of region k after one frequency modulation action is:

[0162]

[0163] in: C is an arbitrary constant.

[0164] When the frequency modulation in region k starts, substituting equation (18) as the initial condition into equation (19) yields:

[0165]

[0166] According to the obtained frequency deviation expression, it can be seen that before reaching the dead time, due to Causes frequency deviation And as time goes by Will continue to increase; after reaching the dead time, due to And as time goes by, Increases exponentially, and finally This change pattern is consistent with the frequency change of the system under the action of primary frequency modulation.

[0167] make The time when region k reaches the maximum frequency deviation can be obtained

[0168]

[0169] Substituting formula (21) into formula (20), we can obtain:

[0170]

[0171] In formula (22), H k and Separation, we can get:

[0172]

[0173] Finally, the separated formula (23) is substituted into the constraint formula to obtain:

[0174]

[0175] After the above processing, the original nonlinear inequality constraints have been transformed into linear inequality constraints, which greatly increases the complexity of model solution and improves computational efficiency.

[0176] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. A person skilled in the art should understand that the specific implementation of the present invention can be modified or replaced by equivalents, but these modifications or changes are within the scope of protection of the pending claims.

Claims

1. A quantitative evaluation method for dynamic regulation demand of a high-proportion renewable energy power system, characterized in that: The method for quantitatively evaluating the dynamic regulation demand of a high-proportion new energy power system comprises the following steps: Step (1): construct a frequency response model of a high-proportion renewable energy power system; Step (2): construct a power system frequency stability demand assessment model; Step (3): Processing of the maximum frequency deviation constraint.

2. According to claim 1, a method for quantitatively evaluating dynamic regulation demand of a high-proportion new energy power system is characterized in that: In step (1), a frequency response model of a high-proportion renewable energy power system is constructed, specifically including a frequency response model of a thermal power unit, a renewable energy grid-connected frequency response model considering virtual synchronous machine control, and a renewable energy system frequency response aggregation model considering the impact of a primary frequency regulation dead zone.

3. According to claim 2, a method for quantitatively evaluating dynamic regulation demand of a high-proportion new energy power system is characterized in that: The specific method for constructing the frequency response model of the thermal power unit is: The primary frequency regulation power linear growth model is used to simulate the frequency regulation process of thermal power units, and its expression is: In the formula Provide primary frequency regulation power for a single thermal power unit, MW; is the primary frequency regulation capacity of a single thermal power unit, MW; T G With t d They are respectively the time when the primary frequency regulation capacity of the synchronous unit is fully put into use and the primary frequency regulation dead zone time of the thermal power unit, s.

4. According to claim 3, a method for quantitatively evaluating dynamic regulation demand of a high-proportion new energy power system is characterized in that: The specific method for constructing the new energy grid-connected frequency response model considering virtual synchronous machine control is: After adding the above control links to the inverter, the virtual inertia instantaneous support power provided by all new energy generating sets and energy storage devices in area k is: Where: is the total power of all virtual synchronous machines participating in the inertial response in area k, MW; is the inertia time constant of all renewable energy generating units and energy storage devices in region k, MW·s; is the frequency deviation of the leading unit in region k, Hz; f N is the system reference frequency, Hz; At this time, the total inertia of area k is H k It is expressed as: Where: is the inertia time constant of all thermal power units in area k, s; after adding the above control links to the inverter, the primary frequency modulation power provided by a single VSM is: Where: Primary frequency regulation power provided for a single VSM, MW; is the primary frequency regulation capacity of a single VSM, MW; Δf d is the dead zone frequency, Hz; Adjust the power per unit value for a single VSM unit.

5. According to claim 4, a method for quantitatively evaluating dynamic regulation demand of a high-proportion new energy power system is characterized in that: The specific method for constructing the frequency response aggregation model of the new energy system considering the influence of the primary frequency modulation dead zone is: Considering the influence of the primary frequency regulation dead zone of thermal power units and VSM, the total primary frequency regulation power of area k is: Where: is the total primary frequency modulation power in area k in MW; k G and k VSM are the total number of single thermal power units and VSM in area k; ΔP Gi (t) and ΔP VSMi (t) are the primary frequency regulation power provided by the i-th thermal power unit and VSM in region k, MW; Before the system frequency deviation is greater than the dead zone frequency, all primary frequency regulation units in area k are not started. After the system frequency deviation is greater than the dead zone frequency, the dead zone frequency is brought into the synchronous unit and VSM primary frequency regulation model. At this time, the sum of the primary frequency regulation powers of all synchronous units and VSM units in area k is expressed as: Where: is the overall coefficient of all synchronous units in region k, MW / s; is the overall frequency modulation coefficient of all VSMs in area k, MW / Hz; n G is the number of all synchronous units in area k.

6. A quantitative evaluation method for dynamic regulation demand of a high-proportion new energy power system according to claim 5, characterized in that: The specific method for constructing the power system frequency stability demand assessment model in step (2) is: The optimization objective of establishing the regional k-frequency stability demand assessment model is: in: Where: Optimize the objective function for the regional k-frequency stability demand assessment model; and They are the minimum inertia requirement optimization objective function of area k and the primary frequency modulation power optimization objective function of area k respectively; is the minimum inertia required for area k, MW / s; The following constraints are mainly considered: (1) Regional overall inertia level constraint The minimum inertia of area k must be maintained between the maximum inertia that all dispatchable units can provide when the area is operating normally and the minimum inertia that can be provided by the dispatchable units when a disturbance occurs and there is no virtual inertia, which can be expressed as: Where: is the lower limit of the overall inertia time constant of all operating synchronous units (including VSM) in area k, s; The upper limit of the total time constant that can be provided by all synchronous machines (including VSM) in area k that can provide inertia, s; (2) Frequency stability constraints The frequency stability constraint is a constraint set to ensure that the system frequency always runs within the system allowable range, mainly considering the RoCoF constraint and the maximum frequency deviation constraint; ①RoCoF constraints The maximum frequency change rate in area k generally occurs at the moment after the disturbance occurs. Under the premise of ensuring that the safety protection measures of the power system do not act, the maximum frequency change rate in area k must be less than the maximum safe frequency change rate specified by the system, which can be expressed as: Where: and are the maximum frequency change rate of the representative unit in area k and the upper limit of the maximum frequency change rate set for the entire system to ensure safe and stable operation, Hz / s; Since the frequency modulation in the area was not started immediately after the disturbance, this constraint is transformed into the following form: Where: is the size of the disturbance assigned to region k, MW; ②Maximum frequency deviation constraint The frequency deviation of region k should always be kept within the maximum frequency deviation allowed by the system: Where: and are the maximum frequency deviation of region k and the maximum frequency deviation allowed by the system, Hz; (3) Quasi-steady-state frequency deviation constraint After one frequency modulation, the frequency of region k reaches a quasi-steady state, which can be expressed as: Where: and are the quasi-steady-state frequency deviation of the representative unit in region k at the end of a frequency modulation and the maximum quasi-steady-state frequency deviation upper limit set for the entire system to ensure safe and stable operation, Hz; D k Damping size in region k, MW / Hz; (4) Power capacity limitation For thermal power units and VSM units, the primary frequency regulation power will be affected by the capacity of their own backup power supply. Under the limitation of the adjustable capacity of the power supply, the primary frequency regulation output limit expression of thermal power units and VSM units is as follows: Where: and are the power output after primary frequency regulation and amplitude limiting of the power supply of the thermal power unit and the VSM unit respectively; R Gi,min With R VSMi,min They are the power limit reduction limits of various power supplies; R Gi,max With R VSMi,max They are the power limit increase limits for each type of power supply.

7. A quantitative evaluation method for dynamic regulation demand of a high-proportion new energy power system according to claim 6, characterized in that: The specific method for processing the maximum frequency deviation constraint in step (3) is: (31) Before the center frequency of region k reaches the frequency dead zone, all units have not acted on the primary frequency regulation. At this time, the rotor motion equation of region k is expressed as: The central frequency deviation expression of region n before a frequency modulation action is obtained as follows: When the frequency in region k reaches the dead zone frequency, the frequency deviation of the critical point is obtained: (32) After the center frequency of region k reaches the frequency dead zone, assuming that all regions have sufficient primary frequency regulation capacity, the maximum frequency deviation of each region is reached before the thermal power unit reaches the maximum frequency regulation power; substituting into the rotor motion equation, we get: The central frequency deviation expression of region k after one frequency modulation action is obtained as follows: in: C is an arbitrary constant; When the frequency modulation in region k starts, substitute equation (18) as the initial condition into equation (19) to obtain: According to the obtained frequency deviation expression, it can be seen that before reaching the dead time, due to Causes frequency deviation And as time goes by Will continue to increase; after reaching the dead time, due to And as time goes by, Increases exponentially, and finally Gradually decreases; this change law is consistent with the frequency change of the system under the action of primary frequency modulation; make Get the time when region k reaches the maximum frequency deviation Substituting formula (21) into formula (20), we get: In formula (22), H k and Separate and get: Finally, the separated formula (23) is substituted into the constraint formula to obtain: After the above processing, the original nonlinear inequality constraints have been transformed into linear inequality constraints, which greatly increases the complexity of model solution and improves computational efficiency.

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