An ordered black start method and system of a new energy power generation unit

Abstract

The present disclosure belongs to the technical field of power system restoration, and particularly relates to an orderly black start method and system of a new energy power generation unit, comprising: acquiring system parameters of the new energy power generation unit; constructing a black start system model of the new energy power generation unit based on the acquired system parameters; evaluating the black start capability of the constructed black start system model to obtain a black start utility output of the new energy power generation unit; and optimizing the start order of the new energy power generation unit according to the acquired system parameters of the new energy power generation unit and the obtained black start utility output, combining an orderly participation algorithm to complete the orderly black start of the new energy power generation unit.

Description

Technical Field

[0001] This disclosure belongs to the field of power system restoration technology, specifically relating to an orderly black start method and system for a new energy power generation unit. Background Technology

[0002] The statements in this section are merely background information relating to this disclosure and do not necessarily constitute prior art.

[0003] In power outages, renewable energy sources are expected to participate in black start operations because they can significantly accelerate the recovery of the power system. Black start is the first stage of power restoration after a major power outage; in this process, black start power sources provide initial power to outaged generator units that lack self-starting capabilities, gradually completing the startup and grid connection of power sources and loads. Black start power sources should generally meet the following requirements: possess self-starting capability, be able to provide sufficient starting power to the generator units being started, and maintain strong voltage and frequency support capabilities during the 3-4 hour black start process.

[0004] Conventional black-start power sources mainly consist of pumped-storage hydroelectric synchronous generators. These power sources offer controllable output and strong disturbance immunity, making them ideal for black-starting. However, due to limitations in resource distribution, investment, and maintenance costs, the number of these power sources is limited, restricting further improvements in the black-start capability of the power system. With the increasing penetration of wind and solar power in the power grid, utilizing the low power requirement and fast start-up speed of combined wind-solar-storage power sources can improve the grid's recovery capability after major power outages.

[0005] The self-starting and regulation capabilities of wind-solar-storage combined power sources participating in black starts need to be accurately assessed to ensure the safety and stability of the recovery process. Based on the recovery system's capacity to support the combined power source, and considering constraints such as generator frequency and voltage regulation capabilities, power regulation margin, and line transmission capacity, the maximum capacity and grid connection timing of the combined power source for recovery are determined. This method primarily analyzes the recovery capability of the combined power source from the perspective of maximum grid-connected capacity, based on overall system indicators. It lacks quantification of the dynamic characteristics of the combined power source, cannot assess the stability of the system during recovery, and is unsuitable for situations where the combined power source dominates the black start process.

[0006] According to the inventors, compared to synchronous generators, wind-solar-storage combined power supplies have poor overcurrent capacity and disturbance rejection capabilities. During black start-up, they are prone to recovery failure due to inverter current limiting, line closing overvoltage, transformer inrush current, and starting load power surges. Combining wind-solar-storage combined power supplies with diesel generators improves disturbance rejection capabilities. Diesel generators can provide grid-connected voltage and reference frequency for the wind-solar-storage combined power supply, which can respond to frequency changes through virtual inertia control, improving active power regulation capabilities. However, the capacity of a single diesel generator unit is small, and as wind and solar power output increases, the stabilizing effect of the diesel generator on wind and solar power power fluctuations is difficult to maintain. Energy storage has excellent controllability and can smooth out fluctuations in the output of wind-solar-storage combined power supplies, but its regulation capability is constrained by power and capacity configuration. By optimizing the capacity and power configuration of energy storage, the fluctuations in wind and solar power output can be smoothed out. However, existing methods address relatively simple black start scenarios and do not consider the differences and coordination among different participants in long-term, multi-timescale black start-up processes. Summary of the Invention

[0007] To address the aforementioned issues, this disclosure proposes an orderly black-start method and system for new energy power generation units. By utilizing the orderly control of new energy power generation stations such as wind power or photovoltaic power plants, the black-start function of the power grid is realized, which is used for online decision-making of black-start plans and can improve the system robustness and stability of black-start for wind power and photovoltaic power generation.

[0008] According to some embodiments, the first solution of this disclosure provides an ordered black start method for a new energy power generation unit, which adopts the following technical solution:

[0009] An ordered black start method for a new energy power generation unit includes:

[0010] Obtain system parameters of the new energy power generation unit;

[0011] A black-start system model of the new energy power generation unit is constructed based on the obtained system parameters;

[0012] The black-start capability of the constructed black-start system model is evaluated to obtain the black-start utility output of the new energy power generation unit;

[0013] Based on the obtained system parameters of the new energy power generation unit and the obtained black start utility output, combined with the ordered participation algorithm, the start-up sequence of the new energy power generation unit is optimized to complete the ordered black start of the new energy power generation unit.

[0014] As a further technical limitation, the system parameters of the new energy power generation unit include the actual value of power generation output, the predicted value of power generation output, the voltage change value, the frequency response power, and the load growth.

[0015] As a further technical limitation, the black start system of the new energy power generation unit includes a wind power system, a photovoltaic system, an energy storage system, a transmission line, and a black start load. During the black start process, the black start load and the wind-solar-storage combined power supply composed of the wind power system, photovoltaic system, and energy storage system are all connected to the main power grid and continuously start up. During the continuous start-up process, the wind-solar-storage combined power supply continuously withstands the impact of transient power.

[0016] Furthermore, in evaluating the black-start capability of the constructed black-start system model, assessments are conducted from both transient and steady-state stability perspectives; the output uncertainty set of the wind-solar-storage combined power source is as follows:

[0017]

[0018]

[0019]

[0020] P G,t =P w,t +P p,t +P e,t

[0021] Among them, P w,t P p,t and P e,t These represent the output of the wind power system, photovoltaic system, and energy storage system, respectively. This represents the predicted output values ​​of wind power systems and photovoltaic systems. and These represent the uplink and downlink power adjustment margins of wind power systems and photovoltaic systems, or the discharge and charging power of energy storage, respectively. and Both represent adjustment factors;

[0022] Considering the long-process characteristics of black-start, the steady-state energy uncertainty set EBS,t+1 of the black-start power source is:

[0023] E BS,t+1 =E BS,t +P BS,t Δt

[0024] The energy of the battery is constrained by its charge and discharge capacity as follows:

[0025] Furthermore, the black-start effect output of the new energy power generation unit is the stable output range that the black-start power supply can maintain, i.e., the confidence range.

[0026] Furthermore, the confidence interval for

[0027]

[0028] Where Pr(·) represents probability calculation, and 1-α represents the confidence level;

[0029] The ramp margin, Prap,t, for the combined wind-solar-storage power generation is:

[0030]

[0031]

[0032] Where Pinc,t represents the load increase and E represents the expected value.

[0033] As a further technical constraint, considering the black-start capability and system stability at different time scales, the frequency and voltage regulation capability of the power supply is evaluated through an ordered participation algorithm on a short-term transient time scale to screen out new energy power generation combinations that can withstand sequential transient impacts. On a long-term steady-state time scale, the startup sequence of the new energy power generation combinations is determined through an ordered participation algorithm to ensure the smoothness of load growth during the black-start process.

[0034] According to some embodiments, the second solution of this disclosure provides an ordered black-start system for a new energy power generation unit, which adopts the following technical solution:

[0035] An ordered black-start system for a new energy power generation unit includes:

[0036] The acquisition module is configured to acquire system parameters of the new energy power generation unit;

[0037] The modeling module is configured to construct a black-start system model of the new energy power generation unit based on the acquired system parameters;

[0038] The evaluation module is configured to evaluate the black-start capability of the constructed black-start system model and obtain the black-start utility output of the new energy power generation unit.

[0039] The optimization module is configured to optimize the startup sequence of the new energy power generation units based on the acquired system parameters and the obtained black-start utility output, combined with the ordered participation algorithm, to complete the ordered black start of the new energy power generation units.

[0040] According to some embodiments, a third aspect of this disclosure provides a computer-readable storage medium, employing the following technical solution:

[0041] A computer-readable storage medium having a program stored thereon that, when executed by a processor, implements the steps in the ordered black-start method for a new energy power generation unit as described in the first aspect of this disclosure.

[0042] According to some embodiments, the fourth solution of this disclosure provides an electronic device that adopts the following technical solution:

[0043] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the ordered black-start method for a new energy power generation unit as described in the first aspect of this disclosure.

[0044] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0045] This disclosure proposes an ordered black-start participation strategy to improve robustness to uncertainties in wind and solar power generation; proposes a multi-timescale framework for optimizing and arranging participation targets for different wind-solar-storage power combinations; considers both short-term control capabilities and long-term power output slope levels; and proposes an ordered participation algorithm for online decision-making in black-start planning to improve the system robustness and stability of black-start for wind and solar power generation. Attached Figure Description

[0046] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure.

[0047] Figure 1 This is a flowchart of the ordered black start method for the new energy power generation unit in Embodiment 1 of this disclosure;

[0048] Figure 2 This is a schematic diagram of a black-start system model dominated by a wind-solar-storage combined power source in Embodiment 1 of this disclosure;

[0049] Figure 3 This is a schematic diagram of the connection between the transmission line and the transformer in Embodiment 1 of this disclosure;

[0050] Figure 4 This is a flowchart of the ordered participation algorithm in Embodiment 1 of this disclosure;

[0051] Figure 5 This is a structural block diagram of the ordered black start system of the new energy power generation unit in Embodiment 2 of this disclosure. Detailed Implementation

[0052] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0053] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0054] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0055] In this disclosure, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationship of the various components or elements in this disclosure, and do not specifically refer to any component or element in this disclosure, nor should they be construed as limiting this disclosure.

[0056] In this disclosure, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this disclosure based on the specific circumstances, and they should not be construed as limitations on this disclosure.

[0057] Where there is no conflict, the embodiments and features described herein can be combined with each other.

[0058] Example 1

[0059] Embodiment 1 of this disclosure introduces an ordered black start method for a new energy power generation unit.

[0060] like Figure 1 The method for ordered black start of a new energy power generation unit, as shown, includes:

[0061] Obtain system parameters of the new energy power generation unit;

[0062] A black-start system model of the new energy power generation unit is constructed based on the obtained system parameters;

[0063] The black-start capability of the constructed black-start system model is evaluated to obtain the black-start utility output of the new energy power generation unit;

[0064] Based on the obtained system parameters of the new energy power generation unit and the obtained black start utility output, combined with the ordered participation algorithm, the start-up sequence of the new energy power generation unit is optimized to complete the ordered black start of the new energy power generation unit.

[0065] This embodiment proposes a black-start strategy to improve the robustness of black-start to the uncertainty of new energy power generation units. Specifically, it is achieved through a short-term simulation model and a long-term ordered participation model: the short-term model involves transient frequency and voltage stability under black-start disturbances, simulates the regulation capability of power plants, and determines whether they can withstand the impact of black-start events; the long-term model involves the power and energy balance of the steady state during black-start, considers the uncertainty of wind and photovoltaic power generation, and calculates a reliable power output range, thereby preventing insufficient power generation caused by renewable energy power fluctuations.

[0066] This embodiment takes a wind-solar-storage combined power source as an example for detailed explanation.

[0067] like Figure 2 The illustrated black-start system, dominated by a wind-solar-storage combined power source, includes a wind power system, a photovoltaic system, an energy storage system, transmission lines, and black-start loads. Due to its inherent characteristics and external uncertainties, the wind-solar-storage combined power source requires appropriate energy storage to enable self-starting and a continuous, stable, and reliable power supply. During the black-start process, the loads and power source will continuously start and connect to the grid. The black-start power source must withstand transient power surges during this period (typically several hours).

[0068] Due to the uncertainty of wind and solar power output and the constraints of energy storage capacity, black-start power supplies must also maintain steady-state energy balance to avoid black-start failure caused by insufficient power output. Therefore, the black-start capability of wind-solar-storage power supplies is evaluated from both transient and steady-state stability perspectives.

[0069] The set of uncertain output power of a black-start power supply can be represented as:

[0070]

[0071]

[0072]

[0073] P G,t =P w,t +P p,t +P e,t (4)

[0074] Among them, P w,t P p,t and P e,t These are the outputs from wind farms, solar power, and energy storage batteries, respectively. These are the predicted values ​​for wind and solar power output. and It refers to the uplink / downlink power adjustment margin of wind / solar power or the discharge / charging power of energy storage. and It is a regulating factor, and is a binary variable.

[0075] Considering the long-process characteristics of the black-start process, the steady-state energy uncertainty set of the power source can be expressed as:

[0076] E BS,t+1 =E BS,t +P BS,t Δt (5)

[0077] The energy of the battery is constrained by its charge and discharge capacity as follows:

[0078]

[0079] like Figure 3 As shown, when a transmission line and a transformer are connected, the inrush current will cause voltage changes. The voltage change of the transmission line is mainly determined by the line inductive reactance. The voltage change of the transformer is composed of two superimposed parts: one part is the voltage drop caused by the transformer leakage reactance, which is similar to the line voltage drop; the other part is the induced electromotive force at both ends of the winding, which is much greater than the leakage reactance voltage drop at the moment of line connection, and may even cause the bus voltage to be too high and trigger the protection action.

[0080] The voltage changes at both ends of the line are as follows:

[0081] ΔU L =jX L I L (7)

[0082] The transformer voltage change is as follows:

[0083]

[0084]

[0085] The reactive power regulation of a black-start power supply can improve bus voltage fluctuations, and their relationship can be expressed as:

[0086]

[0087] Simplifying formula (10), we get:

[0088]

[0089] Bus voltage variations are constrained by upper and lower voltage limits.

[0090]

[0091] The main purpose of black start is to supply power to the load, restoring the power supply and load to normal operation. Since load startup causes a frequency drop, a black start power supply should have frequency response capability.

[0092] The frequency response of wind power consists of two parts: inertial control and pitch angle control. The output change due to inertial control is as follows:

[0093]

[0094] The output change due to pitch angle control is as follows:

[0095]

[0096] It is worth noting that pitch angle control requires changing the direction of the wind turbine blades, and the response speed is affected by the mechanical adjustment speed. Compared with inertial response, the adjustment speed is slower, with response time typically ranging from several seconds to tens of seconds.

[0097] The power output variation of wind power is the sum of the inertial control frequency variation and the pitch control frequency variation:

[0098] ΔP W =ΔP W,ω +ΔP W,β (15)

[0099] The frequency response power of a photovoltaic power station is:

[0100]

[0101] The frequency response power of battery energy storage is:

[0102]

[0103] During a black start, the power supply should limit frequency variations to within the maximum permissible frequency offset:

[0104]

[0105] During black start, the power source must possess a smooth ramp-up capability to accommodate the continuous increase in load. For conventional black start power sources, such as pumped storage hydroelectric generators, this condition is easily met. However, the output of wind and solar power is uncertain; therefore, it is necessary to estimate whether the output level of the combined wind-solar-storage power source can meet the black start requirements over a future period. This involves determining the stable output range that the power source can maintain over a future period T. This is expressed as utility output, i.e.

[0106]

[0107] Where PG,t As defined by formula (4), Pr(·) is the probability calculation, and 1-α is the confidence level. Due to the uncertainty of the power source, the utility output is a confidence interval, and the conservatism of the decision can be adjusted by the parameter α.

[0108] The ramp-up margin of a combined wind-solar-storage power source should meet the needs of load growth:

[0109]

[0110]

[0111] Among them, P ramp,t It is the power supply ramp-up margin, P inc,t E represents the expected increase in load.

[0112] The stability of traditional black-start systems relies on the output reserve and voltage / frequency support capabilities of the black-start power source, assuming that the power output can continuously increase positively, and that the system stability is positively correlated with the size of the generating unit. However, combined wind-solar-storage power systems are affected by output fluctuations, making it impossible to guarantee continuous positive growth in output over the future, and their regulation capabilities are also constrained by multiple factors.

[0113] Therefore, considering the black-start capability and system stability at different time scales, this embodiment employs an ordered participation algorithm for online decision-making in black-start plans. This can improve the system robustness and stability of black-start for wind and solar power generation. The specific process is as follows: Figure 4 As shown.

[0114] On a short-term transient timescale, the ordered participation algorithm evaluates the frequency and voltage regulation capabilities of each power source and selects wind-solar-storage power sources that can withstand sequential transient impacts. On a long-term steady-state timescale, the ordered participation algorithm optimizes the startup sequence of the wind-solar-storage power sources to ensure the stability of load growth during black start.

[0115] This embodiment introduces an ordered black-start participation strategy to improve robustness to uncertainties in wind and solar power generation; proposes a multi-timescale framework for optimizing and arranging participation targets for different wind-solar-storage power combinations; considers both short-term control capabilities and long-term power output slope levels; and proposes an ordered participation algorithm for online decision-making in black-start planning to improve the system robustness and stability of black-start for wind and solar power generation.

[0116] Example 2

[0117] Embodiment 2 of this disclosure introduces an ordered black start system for a new energy power generation unit.

[0118] like Figure 5An ordered black-start system for a new energy power generation unit, as shown, includes:

[0119] The acquisition module is configured to acquire system parameters of the new energy power generation unit;

[0120] The modeling module is configured to construct a black-start system model of the new energy power generation unit based on the acquired system parameters;

[0121] The evaluation module is configured to evaluate the black-start capability of the constructed black-start system model and obtain the black-start utility output of the new energy power generation unit.

[0122] The optimization module is configured to optimize the startup sequence of the new energy power generation units based on the acquired system parameters and the obtained black-start utility output, combined with the ordered participation algorithm, to complete the ordered black start of the new energy power generation units.

[0123] The detailed steps are the same as the ordered black start method for the new energy power generation unit provided in Example 1, and will not be repeated here.

[0124] Example 3

[0125] Embodiment 3 of this disclosure provides a computer-readable storage medium.

[0126] A computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps in the ordered black-start method for a new energy power generation unit as described in Embodiment 1 of this disclosure.

[0127] The detailed steps are the same as the ordered black start method for the new energy power generation unit provided in Example 1, and will not be repeated here.

[0128] Example 4

[0129] Embodiment 4 of this disclosure provides an electronic device.

[0130] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the ordered black start method for a new energy power generation unit as described in Embodiment 1 of this disclosure.

[0131] The detailed steps are the same as the ordered black start method for the new energy power generation unit provided in Example 1, and will not be repeated here.

[0132] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

[0133] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. An ordered black-start method for a new energy power generation unit, characterized in that, include: Obtain system parameters of the new energy power generation unit; A black-start system model of the new energy power generation unit is constructed based on the obtained system parameters; The black-start capability of the constructed black-start system model is evaluated to obtain the black-start utility output of the new energy power generation unit; Based on the obtained system parameters of the new energy power generation unit and the obtained black start utility output, combined with the ordered participation algorithm, the start-up sequence of the new energy power generation unit is optimized to complete the ordered black start of the new energy power generation unit. In evaluating the black-start capability of the constructed black-start system model, assessments were conducted from both transient and steady-state stability perspectives. The output uncertainty set of the wind-solar-storage combined power source is as follows: in, , and These represent the output of the wind power system, photovoltaic system, and energy storage system, respectively. This represents the predicted output values ​​of wind power systems and photovoltaic systems. and These represent the uplink and downlink power adjustment margins of wind power systems and photovoltaic systems, or the discharge and charging power of energy storage, respectively. and Both represent adjustment factors; Considering the long-process characteristics of black-start, the set of uncertain steady-state energies of the black-start power source is... for: The energy of the battery is constrained by its charge and discharge capacity as follows: ; The black-start effect output of the new energy power generation unit is the stable output range that the black-start power supply can maintain, i.e., the confidence range. The confidence interval for in, Indicates probability calculation. Indicates the confidence level; Ramp-up margin of wind-solar-storage combined power generation for: in, E represents the load increase, and E represents the expected increase.

2. The ordered black start method for a new energy power generation unit as described in claim 1, characterized in that, The system parameters of the new energy power generation unit include the actual value of power generation output, the predicted value of power generation output, the voltage change value, the frequency response power, and the load growth.

3. The ordered black start method for a new energy power generation unit as described in claim 1, characterized in that, The black start system of the new energy power generation unit includes a wind power system, a photovoltaic system, an energy storage system, a transmission line, and a black start load. During the black start process, the black start load and the wind-solar-storage combined power supply composed of the wind power system, photovoltaic system, and energy storage system are connected to the main power grid and continuously start. During the continuous start process, the wind-solar-storage combined power supply continuously withstands transient power impacts.

4. The ordered black start method for a new energy power generation unit as described in claim 1, characterized in that, Taking into account the black-start capability and system stability at different time scales, in the short-term transient time scale, the frequency and voltage regulation capability of the power source is evaluated by the ordered participation algorithm to screen out the new energy power generation combination power sources that can withstand the sequential transient impact; in the long-term steady-state time scale, the startup sequence of the new energy power generation combination power sources is determined by the ordered participation algorithm to ensure the smoothness of load growth during the black start process.

5. An ordered black-start system for a new energy power generation unit, used in the ordered black-start method for a new energy power generation unit according to any one of claims 1-4, characterized in that, include: The acquisition module is configured to acquire system parameters of the new energy power generation unit; The modeling module is configured to construct a black-start system model of the new energy power generation unit based on the acquired system parameters; The evaluation module is configured to evaluate the black-start capability of the constructed black-start system model and obtain the black-start utility output of the new energy power generation unit. The optimization module is configured to optimize the startup sequence of the new energy power generation units based on the acquired system parameters and the obtained black-start utility output, combined with the ordered participation algorithm, to complete the ordered black start of the new energy power generation units.

6. A computer-readable storage medium having a program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the ordered black start method of the new energy power generation unit as described in any one of claims 1-4.

7. An electronic device comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the ordered black start method of the new energy power generation unit as described in any one of claims 1-4.

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