A direct current fault-based new energy power generation unit power control method and system

Abstract

The application relates to a new energy power generation unit power control method and system based on DC faults, and the method comprises the following steps: detecting a fault mode of a high-voltage DC power transmission system; determining an active power reference value of a new energy power generation unit according to the fault mode of the high-voltage DC power transmission system; and adjusting the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit. The technical scheme provided by the application makes the output active power of the new energy power generation unit change along with the fault mode of the high-voltage DC power transmission system, thereby avoiding accidents caused by excessive new energy active power when the high-voltage DC power transmission channel is blocked, improving the transient stability operation capability of the high-voltage DC power transmission system under DC faults, and realizing reliable transmission of the active power sent by the new energy power generation unit under DC faults.

Description

Technical Field

[0001] This invention relates to the field of new energy power transmission technology, specifically to a power control method and system for new energy power generation units based on DC faults. Background Technology

[0002] High-voltage direct current (HVDC) transmission is a core technology for building the future smart grid, facilitating the integration of new energy sources and long-distance power transmission. Large-scale new energy transmission over long distances using HVDC grids has already begun in practice, and multiple HVDC transmission lines have been constructed to address the power transmission needs of large-scale new energy bases.

[0003] Because the time scale of the alternating current of renewable energy generation is inconsistent with the time scale of the DC voltage of the high-voltage direct current (HVDC) grid, the transient response times of renewable energy and the HVDC grid differ. Furthermore, the DC converter station provides isolation. This leads to a situation where, after a fault-induced blockage on the HVDC side, the transmission channel of the HVDC transmission system is obstructed, but the renewable energy generation units do not perceive this change and continue generating electricity normally. The DC power transmitted by the renewable energy generation units exceeds the capacity limit of the HVDC voltage. Consequently, the current on the renewable energy generation side of the HVDC transmission system drops rapidly, the system voltage rises, and the transmission continuity of the HVDC transmission system deteriorates. In addition, because the active power of renewable energy cannot be transmitted, the electromagnetic power of renewable energy generation drops sharply. While the mechanical power of renewable energy generation may be considered constant in the short term, over a long period, this leads to an imbalance between the mechanical power and electromagnetic power of renewable energy generation, causing the renewable energy generation units to malfunction.

[0004] DC-side short-circuit faults are a serious type of fault that must be considered in the operation of high-voltage direct current transmission systems. Overhead transmission lines have exposed conductors outdoors, making them prone to temporary faults such as short circuits and flashovers. The ability to clear and cross DC faults urgently needs to be improved.

[0005] In response to the problem of reduced transmission capacity of high-voltage direct current (HVDC) transmission channels and the resulting obstruction of large-scale renewable energy power transmission leading to the expansion of accidents under DC-side faults, many scholars have conducted extensive research. Currently, two methods have been proposed. One method is based on triggering the fault ride-through control mode by measuring the renewable energy variable threshold. However, this method requires creating a voltage drop on the power supply side to trigger the renewable energy fault ride-through control threshold. Creating a new voltage drop may affect the stable operation of the power grid on the power supply side and poses a risk of generating other accidents. At the same time, this method does not meet the requirements of rapid response of HVDC power grids.

[0006] One approach is to configure large-capacity energy-consuming resistors on the renewable energy side to consume excess renewable energy. However, this method requires large-scale equipment, and the configuration and operation of large energy-consuming devices will increase the cost on the power supply side. Furthermore, the energy-consuming devices have limited power consumption capacity, ultimately requiring the power supply to adjust the active power output.

[0007] How to control the active power of new energy power generation units to adapt to the operating conditions of high-voltage direct current transmission channels, so as to achieve the goal of stable system operation after a fault, while avoiding the risks of configuring large equipment and causing other accidents, is an urgent problem to be solved. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the purpose of this invention is to propose a power control method for new energy power generation units based on DC faults. This method enables the output active power of the new energy power generation unit to change with the fault mode of the high-voltage direct current transmission system, thereby avoiding accidents caused by excessive active power of new energy sources when the high-voltage direct current transmission channel is blocked, improving the transient stability operation capability of the high-voltage direct current transmission system under DC faults, and realizing the reliable transmission of active power sent by the new energy power generation unit under DC faults.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] This invention provides a power control method for a new energy power generation unit based on DC faults, the improvement of which is that the method includes:

[0011] Detecting fault modes in high-voltage direct current transmission systems;

[0012] The active power reference value of the new energy power generation unit is determined based on the fault mode of the high voltage direct current transmission system.

[0013] The active power of the new energy power generation unit is adjusted according to the active power reference value of the new energy power generation unit.

[0014] Preferably, the detection of fault modes in the high-voltage direct current transmission system includes:

[0015] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that time is no fault, then the fault mode of the high-voltage direct current transmission system at that time is no fault.

[0016] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault.

[0017] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent negative pole blocking fault;

[0018] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault.

[0019] Among them, permanent unipolar blockage faults include permanent negative blockage faults and permanent positive blockage faults; U dc It is the absolute value of the rated DC voltage of the high-voltage DC grid in the high-voltage DC transmission system.

[0020] Preferably, determining the active power reference value of the new energy power generation unit based on the fault mode of the high-voltage direct current transmission system at the current time t includes:

[0021] If the fault mode of the HVDC transmission system at current time t is no fault, the fault mode of the HVDC transmission system at current time t is different from the fault mode at the previous time t, and the fault mode of the HVDC transmission system is the same from current time t to time t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at time t+Δt. ref =P s (t);

[0022] If the fault mode of the HVDC transmission system at the current time t is a permanent unipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value of the new energy power generation unit will be adjusted at t+Δt.

[0023] If the fault mode of the HVDC transmission system at the current time t is a permanent bipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from that at the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at t+Δt. ref =0;

[0024] Among them, P s (t) represents the active power output value of the new energy power generation unit at the current time t; P f Δt represents the transmission capacity of the high-voltage direct current (HVDC) grid in the HVDC transmission system; N represents the total number of new energy power generation units; and Δt represents the time required to determine a permanent fault in the HVDC transmission system.

[0025] Preferably, adjusting the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit includes:

[0026] If the new energy power generation unit is a doubly-fed wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0027]

[0028] In the formula, K d T is the proportional coefficient of the inner current loop for doubly-fed wind turbines. d i is the integral time constant of the inner loop current of the doubly-fed wind turbine; rd_ref (x) represents the actual d-axis current output value of the rotor-side current control loop of the doubly-fed wind turbine before it participates in regulation at time x; i rd (x) represents the d-axis current of the rotor-side current control loop of the doubly-fed wind turbine at time x; α represents the induction coefficient of the doubly-fed wind turbine; and s represents the Laplace operator.

[0029] The d-axis current i of the rotor-side current control loop of the doubly-fed wind turbine at time x is determined by the following formula. rd (x):

[0030]

[0031] In the formula, K p T is the power outer ring proportional coefficient of the doubly-fed wind turbine; p P is the power outer loop integral time constant of the doubly-fed wind turbine; ref (x) represents the reference value of active power of the doubly-fed wind turbine at time x; P gen (x) represents the actual active power output of the doubly fed wind turbine unit before it participates in regulation at time x;

[0032] The induction coefficient α of the doubly-fed wind turbine is determined by the following formula:

[0033]

[0034] In the formula, L s For the stator self-inductance of a doubly-fed wind turbine; L r For the self-inductance of the doubly-fed wind turbine rotor; L m The mutual inductance between the stator and rotor of a doubly-fed wind turbine;

[0035] If the new energy power generation unit is a direct-drive wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0036]

[0037] In the formula, K dz T is the current inner loop proportional coefficient for direct-drive wind turbines; dz The current inner loop integral time constant of the direct-drive wind turbine; This is the d-axis current reference value for the current control loop of the direct-drive wind turbine at time x. This represents the actual d-axis current output value of the direct-drive wind turbine before it participates in the current control circuit at time x, before it is regulated.

[0038] The d-axis current reference value of the current control loop of the direct-drive wind turbine at time x is determined by the following formula.

[0039]

[0040] In the formula, P meas-z (x) represents the actual active power output of the direct-drive wind turbine before it participates in regulation at time x; T pz K represents the power outer loop integral time constant of a direct-drive wind turbine; pz This is the power outer ring proportional coefficient for direct-drive wind turbine units;

[0041] If the new energy power generation unit is a photovoltaic power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0042]

[0043] In the formula, K dg T is the current inner loop proportionality coefficient of the photovoltaic power generation unit; dg Let be the time constant of the inner loop current of the photovoltaic power generation unit; This is the d-axis current reference value for the current control loop of the photovoltaic power generation unit at time x; This represents the actual d-axis current output value of the current control loop of the photovoltaic power generation unit before it participates in regulation at time x.

[0044] The d-axis current reference value of the current control loop of the photovoltaic power generation unit at time x is determined by the following formula.

[0045]

[0046] In the formula, P meas-g (x) represents the actual active power output of the photovoltaic power generation unit before it participates in regulation at time x; T pg K represents the power outer-loop integral time constant of the photovoltaic power generation unit; pg This is the power outer loop ratio coefficient of the photovoltaic power generation unit.

[0047] This invention provides a power control system for a new energy power generation unit based on DC faults, the improvement of which is that the system includes:

[0048] Detection module: Used to detect fault modes in high-voltage direct current transmission systems;

[0049] Determining module: Used to determine the active power reference value of the new energy power generation unit based on the fault mode of the high voltage direct current transmission system;

[0050] Adjustment module: used to adjust the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit.

[0051] Preferably, the detection module is used for:

[0052] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that time is no fault, then the fault mode of the high-voltage direct current transmission system at that time is no fault.

[0053] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault.

[0054] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent negative pole blocking fault;

[0055] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault.

[0056] Among them, permanent unipolar blockage faults include permanent negative blockage faults and permanent positive blockage faults; U dc It is the absolute value of the rated DC voltage of the high-voltage DC grid in the high-voltage DC transmission system.

[0057] Preferably, the determining module is used for:

[0058] If the fault mode of the HVDC transmission system at current time t is no fault, the fault mode of the HVDC transmission system at current time t is different from the fault mode at the previous time t, and the fault mode of the HVDC transmission system is the same from current time t to time t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at time t+Δt. ref =P s (t);

[0059] If the fault mode of the HVDC transmission system at the current time t is a permanent unipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value of the new energy power generation unit will be adjusted at t+Δt.

[0060] If the fault mode of the HVDC transmission system at the current time t is a permanent bipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from that at the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at t+Δt. ref =0;

[0061] Among them, P s (t) represents the active power output value of the new energy power generation unit at the current time t; P fΔt represents the transmission capacity of the high-voltage direct current (HVDC) grid in the HVDC transmission system; N represents the total number of new energy power generation units; and Δt represents the time required to determine a permanent fault in the HVDC transmission system.

[0062] Preferably, the adjustment module is used for:

[0063] If the new energy power generation unit is a doubly-fed wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0064]

[0065] In the formula, K d T is the proportional coefficient of the inner current loop for doubly-fed wind turbines. d i is the integral time constant of the inner loop current of the doubly-fed wind turbine; rd_ref (x) represents the actual d-axis current output value of the rotor-side current control loop of the doubly-fed wind turbine before it participates in regulation at time x; i rd (x) represents the d-axis current of the rotor-side current control loop of the doubly-fed wind turbine at time x; α represents the induction coefficient of the doubly-fed wind turbine; and s represents the Laplace operator.

[0066] The d-axis current i of the rotor-side current control loop of the doubly-fed wind turbine at time x is determined by the following formula. rd (x):

[0067]

[0068] In the formula, K p T is the power outer ring proportional coefficient of the doubly-fed wind turbine; p P is the power outer loop integral time constant of the doubly-fed wind turbine; ref (x) represents the reference value of active power of the doubly-fed wind turbine at time x; P gen (x) represents the actual active power output of the doubly fed wind turbine unit before it participates in regulation at time x;

[0069] The induction coefficient α of the doubly-fed wind turbine is determined by the following formula:

[0070]

[0071] In the formula, L s For the stator self-inductance of a doubly-fed wind turbine; L r For the self-inductance of the doubly-fed wind turbine rotor; L m The mutual inductance between the stator and rotor of a doubly-fed wind turbine;

[0072] If the new energy power generation unit is a direct-drive wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0073]

[0074] In the formula, K dz T is the current inner loop proportional coefficient for direct-drive wind turbines; dz The current inner loop integral time constant of the direct-drive wind turbine; This is the d-axis current reference value for the current control loop of the direct-drive wind turbine at time x. This represents the actual d-axis current output value of the direct-drive wind turbine before it participates in the current control circuit at time x, before it is regulated.

[0075] The d-axis current reference value of the current control loop of the direct-drive wind turbine at time x is determined by the following formula.

[0076]

[0077] In the formula, P meas-z (x) represents the actual active power output of the direct-drive wind turbine before it participates in regulation at time x; T pz K represents the power outer loop integral time constant of a direct-drive wind turbine; pz This is the power outer ring proportional coefficient for direct-drive wind turbine units;

[0078] If the new energy power generation unit is a photovoltaic power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0079]

[0080] In the formula, K dg T is the current inner loop proportionality coefficient of the photovoltaic power generation unit; dg Let be the time constant of the inner loop current of the photovoltaic power generation unit; This is the d-axis current reference value for the current control loop of the photovoltaic power generation unit at time x; This represents the actual d-axis current output value of the current control loop of the photovoltaic power generation unit before it participates in regulation at time x.

[0081] The d-axis current reference value of the current control loop of the photovoltaic power generation unit at time x is determined by the following formula.

[0082]

[0083] In the formula, P meas-g(x) represents the actual active power output of the photovoltaic power generation unit before it participates in regulation at time x; T pg K represents the power outer-loop integral time constant of the photovoltaic power generation unit; pg This is the power outer loop ratio coefficient of the photovoltaic power generation unit.

[0084] Compared with the closest existing technology, the present invention has the following advantages:

[0085] The technical solution proposed in this invention detects the fault modes of a high-voltage direct current (HVDC) transmission system; determines the active power reference value of a new energy power generation unit based on the fault modes of the HVDC transmission system; adjusts the active power of the new energy power generation unit according to the active power reference value; enables the new energy power generation unit to quickly adjust its active power even without detecting abnormal signals; ensures that the active power transmitted by the new energy power generation unit will always be less than or equal to the transmission capacity of the HVDC transmission system, preventing the HVDC transmission system from overloading due to excess active power at the sending end, thereby avoiding accidents caused by excessive active power from new energy sources due to obstruction of the HVDC transmission channel, improving the transient stability of the HVDC transmission system under DC faults, and achieving reliable transmission of active power transmitted by the new energy power generation unit under DC faults. Attached Figure Description

[0086] Figure 1 This is a flowchart of a power control method for a new energy power generation unit based on DC faults;

[0087] Figure 2 This is a structural diagram of the transient stable system in an embodiment of the present invention;

[0088] Figure 3 This is a control structure diagram of a doubly fed wind turbine in an embodiment of the present invention;

[0089] Figure 4 This is a schematic diagram of the DC voltage on the new energy power station side during a momentary fault in the high-voltage direct current transmission system according to an embodiment of the present invention;

[0090] Figure 5 This is a schematic diagram of the active power transmitted by the high-voltage direct current grid during a momentary fault in the high-voltage direct current transmission system in an embodiment of the present invention;

[0091] Figure 6 This is a schematic diagram of the DC voltage on the new energy power station side when a permanent fault occurs in the high-voltage direct current transmission system according to an embodiment of the present invention;

[0092] Figure 7 This is a schematic diagram of the active power transmitted by the high-voltage direct current grid when a permanent fault occurs in the high-voltage direct current transmission system in an embodiment of the present invention;

[0093] Figure 8This is a structural diagram of a power control system for a new energy power generation unit based on DC faults. Detailed Implementation

[0094] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0095] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0096] This invention provides a power control method for new energy power generation units based on DC faults. It focuses on the differences between the transient characteristics of the AC time scale of the new energy power generation unit and the DC time scale of the high-voltage direct current (HVDC) transmission system. By fully utilizing wide-area measurement technology and high-speed communication technology, as well as the rapid and controllable characteristics of the active power of the new energy power generation unit, a transient stability control process suitable for scenarios where the active power output from the new energy power generation unit is transmitted through the HVDC transmission system is established. Figure 1 As shown, the method includes:

[0097] Step 101. Detect the fault modes of the high-voltage direct current transmission system;

[0098] Step 102. Determine the reference value of active power for the new energy power generation unit based on the fault modes of the high-voltage direct current transmission system;

[0099] Step 103. Adjust the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit.

[0100] Specifically, step 101 includes:

[0101] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that time is no fault, then the fault mode of the high-voltage direct current transmission system at that time is no fault.

[0102] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault.

[0103] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent negative pole blocking fault;

[0104] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault.

[0105] Among them, permanent unipolar blockage faults include permanent negative blockage faults and permanent positive blockage faults; U dc It is the absolute value of the rated DC voltage of the high-voltage DC grid in the high-voltage DC transmission system.

[0106] In the preferred embodiment of the present invention, it can be as follows: Figure 2 In the application scenario shown, step 101 is performed. Figure 2 The system shown includes:

[0107] The real-time wide-area information monitoring module is used to monitor variables that reflect the operating status of the high-voltage DC power grid, such as the positive and negative DC voltage and DC current of the DC side of the high-voltage DC transmission system, as well as variables that reflect the operating status of the new energy power generation unit, such as the active power and terminal voltage of the new energy power generation unit.

[0108] Key variable extraction module: Used to extract the DC voltage at the positive terminal of the HVDC grid in a HVDC transmission system from massive amounts of data. DC voltage at the negative terminal And the active power of each new energy power generation unit;

[0109] Fault identification module: used to identify the time t when the fault mode of the high voltage direct current transmission system changes, the fault mode of the high voltage direct current transmission system at time t, and whether the change in the fault mode of the high voltage direct current transmission system at time t is permanent.

[0110] If the fault modes of the HVDC transmission system are different from the current time t to t+Δt, it indicates that a transient fault has occurred in the HVDC transmission system. The HVDC transmission system will recover to the previous fault mode in a short time. Therefore, no control should be performed, and the operation of the transient stabilization system ends here.

[0111] If the fault modes of the HVDC transmission system are the same from the current time t to t+Δt, it indicates that a permanent fault has occurred in the HVDC transmission system. In this case, the fault identification module sends the fault mode information of the HVDC transmission system at the current time t to the control measure quantification calculation module.

[0112] When the high-voltage direct current (HVDC) transmission system is functioning without faults, its transmission capacity is at its rated capacity. In this case, the upper limit of the active power of new energy power generation should be the rated capacity of the HVDC transmission system. Under normal circumstances, new energy power generation units generate electricity at their maximum output.

[0113] When the bipolar permanent blockade of the high-voltage direct current transmission system occurs, the high-voltage direct current transmission system loses its power transmission capacity, and all new energy power generation needs to be shut down.

[0114] When a single pole of a high-voltage direct current (HVDC) transmission system is permanently blocked, the transmission capacity of the HVDC transmission system is reduced to half of its rated capacity. The upper limit of the active power of new energy power generation should be half of the rated capacity of the HVDC transmission system, and the output of new energy power generation should be controlled below the limit.

[0115] When a permanent fault occurs in the high-voltage direct current (HVDC) grid, the transient stability control system (TSS) determines the grid's transmission capacity during the fault period based on the fault conditions and sends an active power control signal to the renewable energy generation unit. Upon receiving the active power control signal from the TSS, the renewable energy generation unit immediately adjusts its active power output value to adapt to the HVDC grid's transmission capacity during the fault. After the HVDC grid fault is restored, the renewable energy generation unit resumes its active power output according to the active power control requirements issued by the TSS.

[0116] After detecting a fault mode in the high-voltage direct current (HVDC) transmission system, it is necessary to determine the active power reference value of the new energy power generation unit based on the fault mode of the HVDC transmission system. Therefore, step 102 includes:

[0117] If the fault mode of the HVDC transmission system at current time t is no fault, the fault mode of the HVDC transmission system at current time t is different from the fault mode at the previous time t, and the fault mode of the HVDC transmission system is the same from current time t to time t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at time t+Δt. ref =P s (t);

[0118] If the fault mode of the HVDC transmission system at the current time t is a permanent unipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value of the new energy power generation unit will be adjusted at t+Δt.

[0119] If the fault mode of the HVDC transmission system at the current time t is a permanent bipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from that at the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at t+Δt. ref =0;

[0120] Among them, P s (t) represents the active power output value of the new energy power generation unit at the current time t; P f N represents the transmission capacity of the high-voltage direct current (HVDC) grid in the HVDC transmission system; N represents the total number of new energy power generation units; Δt represents the determination time of a permanent fault in the HVDC transmission system; Δt is a very short time, generally not exceeding 20ms.

[0121] In specific embodiments of the present invention, it is possible to, for example Figure 2 In the application scenario shown, step 102 is performed. Figure 2 The system shown includes:

[0122] The control measure quantification calculation module is used to calculate the active power reference value of the new energy power generation unit based on the received fault mode information of the high voltage DC transmission system at the current time t, and send the value to the new energy power generation unit.

[0123] If the high-voltage direct current transmission system does not meet the above conditions, it indicates that the high-voltage direct current transmission system has experienced a transient change in fault mode or no change in fault mode. In such cases, it is not necessary to adjust the active power reference value of the new energy power generation unit.

[0124] Furthermore, step 103 includes:

[0125] If the new energy power generation unit is a doubly-fed wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0126]

[0127] In the formula, K d T is the proportional coefficient of the inner current loop for doubly-fed wind turbines. di is the integral time constant of the inner loop current of the doubly-fed wind turbine; rd_ref (x) represents the actual d-axis current output value of the rotor-side current control loop of the doubly-fed wind turbine before it participates in regulation at time x; i rd (x) represents the d-axis current of the rotor-side current control loop of the doubly-fed wind turbine at time x; α represents the induction coefficient of the doubly-fed wind turbine; and s represents the Laplace operator.

[0128] In the preferred embodiment of the present invention, new energy power generation generally uses a vector control method based on phase-locked loop synchronization, in which the phase-locked loop drives the internal potential phase change to achieve synchronous operation with the power grid.

[0129] The new energy power generation unit can achieve decoupled control of active and reactive power, which means that the active power of the new energy power generation unit can be quickly and flexibly adjusted as needed. Taking a doubly-fed wind turbine as an example, Figure 3 This is a block diagram of the rotor-side converter control for a doubly-fed induction generator (DFIG). The power measurement module measures the active and reactive power generated by the entire DFIG generator and transmits the signals to the rotor-side inverter controller. The current measurement module measures the active and reactive current (dq components) generated by the DFIG generator rotor and transmits the signals to the rotor-side inverter controller.

[0130] P ref and Q ref These are the reference values ​​for reactive power and active power of a doubly-fed induction generator (DFIG) wind turbine, respectively; K p T is the power outer ring proportional coefficient of the doubly-fed wind turbine; p K represents the power outer loop integral time constant of the doubly-fed wind turbine; d T is the proportional coefficient of the inner current loop for doubly-fed wind turbine generators. d i is the integral time constant of the inner loop current of the doubly-fed wind turbine generator; rd_ref and i rq_ref These are the d-axis and q-axis current reference values ​​for the rotor-side current control circuit of a doubly-fed wind turbine, respectively.

[0131] The power outer loop of the rotor-side converter is based on the active power reference value P of the doubly-fed wind turbine. ref The d-axis current reference value i of the rotor-side current control loop of the doubly-fed wind turbine can be obtained. rd_ref Based on i rd_ref and i rd This allows us to obtain the rotor current control value of the doubly-fed wind turbine. The active power of the doubly-fed wind turbine can be expressed by the following formula:

[0132]

[0133] Among them, P G P represents the active power of the doubly-fed wind turbine generator; genThis refers to the measured active power value of a doubly-fed induction generator (DFIG) wind turbine. rd This refers to the d-axis measurement value of the current in a doubly-fed wind turbine generator; i rd_ref This refers to the q-axis measurement value of the doubly-fed induction generator current; ω s L is the stator synchronous speed of the doubly-fed wind turbine; m For the mutual inductance between the stator and rotor of a doubly-fed wind turbine; L s For the stator self-inductance of the doubly-fed wind turbine; L r This refers to the rotor self-inductance of a doubly fed wind turbine.

[0134] pass Figure 3 As can be seen from the above formula, the active power output value of the doubly-fed wind turbine can be adjusted by adjusting the active power reference value of the doubly-fed wind turbine.

[0135] After the HVDC converter station in the HVDC transmission system restarts, the transmission channel for renewable energy power generation is restored. However, at the moment the renewable energy power generation transmission channel is restored upon restarting the HVDC converter station, there will be a certain amount of overcurrent in the renewable energy power generation. Afterward, the renewable energy power generation gradually returns to the state before the HVDC converter station was locked in the HVDC transmission system.

[0136] The d-axis current i of the rotor-side current control loop of the doubly-fed wind turbine at time x is determined by the following formula. rd (x):

[0137]

[0138] In the formula, K p T is the power outer ring proportional coefficient of the doubly-fed wind turbine; p P is the power outer loop integral time constant of the doubly-fed wind turbine; ref (x) represents the reference value of active power of the doubly-fed wind turbine at time x; P gen (x) represents the actual active power output of the doubly fed wind turbine unit before it participates in regulation at time x;

[0139] The induction coefficient α of the doubly-fed wind turbine is determined by the following formula:

[0140]

[0141] In the formula, L s For the stator self-inductance of a doubly-fed wind turbine; L r For the self-inductance of the doubly-fed wind turbine rotor; L m The mutual inductance between the stator and rotor of a doubly-fed wind turbine;

[0142] If the new energy power generation unit is a direct-drive wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0143]

[0144] In the formula, K dz T is the current inner loop proportional coefficient for direct-drive wind turbines; dz The current inner loop integral time constant of the direct-drive wind turbine; This is the d-axis current reference value for the current control loop of the direct-drive wind turbine at time x. This represents the actual d-axis current output value of the direct-drive wind turbine before it participates in the current control circuit at time x, before it is regulated.

[0145] The d-axis current reference value of the current control loop of the direct-drive wind turbine at time x is determined by the following formula.

[0146]

[0147] In the formula, P meas-z (x) represents the actual active power output of the direct-drive wind turbine before it participates in regulation at time x; T pz K represents the power outer loop integral time constant of a direct-drive wind turbine; pz This is the power outer ring proportional coefficient for direct-drive wind turbine units;

[0148] If the new energy power generation unit is a photovoltaic power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0149]

[0150] In the formula, K dg T is the current inner loop proportionality coefficient of the photovoltaic power generation unit; dg Let be the time constant of the inner loop current of the photovoltaic power generation unit; This is the d-axis current reference value for the current control loop of the photovoltaic power generation unit at time x; This represents the actual d-axis current output value of the current control loop of the photovoltaic power generation unit before it participates in regulation at time x.

[0151] The d-axis current reference value of the current control loop of the photovoltaic power generation unit at time x is determined by the following formula.

[0152]

[0153] In the formula, P meas-g (x) represents the actual active power output of the photovoltaic power generation unit before it participates in regulation at time x; T pg K represents the power outer-loop integral time constant of the photovoltaic power generation unit; pgThis is the power outer loop ratio coefficient of the photovoltaic power generation unit.

[0154] In the preferred embodiment of the present invention, the new energy power generation unit receives an active power reference value instruction and immediately adjusts the output of the new energy power generation unit; and for a period of time thereafter, it controls the output of the new energy power generation unit according to the received active power reference value instruction until the new energy power generation unit receives the next active power reference value instruction.

[0155] In the preferred embodiment of the present invention, a new energy power plant with an installed capacity of 100MW is transmitted through a high-voltage direct current transmission system and connected to the receiving-end AC power grid.

[0156] The new energy power station has 50 2MW generating units, operating at full capacity, with an active power output of 100MW; the high-voltage direct current transmission system has a rated DC voltage of 100kV and a rated transmission capacity of 100MW. Simulations are performed for both transient and permanent fault scenarios.

[0157] Transient fault. Assume that a transient short-circuit fault occurs on the positive DC line of the high-voltage direct current transmission system at 1 second, and the fault is cleared after 20 ms, and normal operation is restored. Figure 4 The DC voltage on the new energy power station side when a transient short-circuit fault occurs on the positive DC line of a high-voltage direct current transmission system. Figure 5 This refers to the active power transmitted by the high-voltage direct current (HVDC) grid when a transient short-circuit fault occurs in the positive DC line of the HVDC transmission system.

[0158] Following the fault, the DC voltage of the HVDC power grid in the HVDC transmission system drops, and the active power decreases. Because it is a transient fault, the HVDC power grid can quickly resume operation; therefore, it can be assumed that the HVDC power grid can maintain its rated transmission capacity, and the new energy power generation units do not need to adjust their active power output. After the fault is quickly cleared, the DC voltage recovers, and the active power of the HVDC power grid returns to its pre-fault level.

[0159] Permanent Fault. Assume that a permanent short-circuit fault occurs on the positive DC line of the high-voltage DC power grid in the high-voltage DC transmission system at time 1 second. The positive line is blocked and taken out of operation, while the negative line continues to operate normally. Figure 6 This refers to the DC voltage on the new energy power station side when a permanent short-circuit fault occurs on the positive DC line of the high-voltage DC grid in a high-voltage DC transmission system. Figure 7 This refers to the active power transmitted by the high-voltage direct current (HVDC) grid when a permanent short-circuit fault occurs on the positive DC line of the HVDC grid in a HVDC transmission system.

[0160] After the fault occurs, the positive terminal of the HVDC grid is locked out and taken out of operation, while the negative terminal continues to operate normally. The transient stability control system detects that the voltage at the positive terminal of the HVDC grid drops to 0, while the voltage at the negative terminal remains normal. The fault mode is identified as M1, i.e., a unipolar fault. It is determined that the transmission capacity of the HVDC grid is reduced to half of its rated capacity, i.e., 50MW. The active power limit for each renewable energy generation unit can be calculated to be 50MW / 50 = 1MW. The transient stability control system sends an active power control signal to each generation unit, with a reference value of 1MW for each unit. Upon receiving the reference value, the renewable energy generation unit adjusts its active power output to match the transmission capacity of the HVDC grid, thus ensuring reliable transmission of renewable energy through the HVDC grid.

[0161] This invention provides a power control system for a new energy power generation unit based on DC faults, such as... Figure 8 As shown, the system includes:

[0162] Detection module: Used to detect fault modes in high-voltage direct current transmission systems;

[0163] Determining module: Used to determine the active power reference value of the new energy power generation unit based on the fault mode of the high voltage direct current transmission system;

[0164] Adjustment module: used to adjust the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit.

[0165] Specifically, the detection module is used for:

[0166] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that time is no fault, then the fault mode of the high-voltage direct current transmission system at that time is no fault.

[0167] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is permanent positive pole blocking fault.

[0168] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is permanent negative pole blocking fault;

[0169] When the absolute value of the positive DC voltage of the high-voltage DC grid in the high-voltage DC transmission system at the current moment satisfy Furthermore, the absolute value of the negative DC voltage of the high-voltage DC grid at the current moment in the high-voltage DC transmission system. satisfy If the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault, then the fault mode of the high-voltage direct current transmission system at that moment is a permanent bipolar blocking fault.

[0170] Among them, permanent unipolar blockage faults include permanent negative blockage faults and permanent positive blockage faults; U dc It is the absolute value of the rated DC voltage of the high-voltage DC grid in the high-voltage DC transmission system.

[0171] Specifically, the determining module is used for:

[0172] If the fault mode of the HVDC transmission system at current time t is no fault, the fault mode of the HVDC transmission system at current time t is different from the fault mode at the previous time t, and the fault mode of the HVDC transmission system is the same from current time t to time t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at time t+Δt. ref =P s (t);

[0173] If the fault mode of the HVDC transmission system at the current time t is a permanent unipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value of the new energy power generation unit will be adjusted at t+Δt.

[0174] If the fault mode of the HVDC transmission system at the current time t is a permanent bipolar blocking fault, and the fault mode of the HVDC transmission system at the current time t is different from that at the time before t, but the fault mode of the HVDC transmission system is the same from the current time t to t+Δt, then the active power reference value P of the new energy power generation unit will be adjusted at t+Δt. ref =0;

[0175] Among them, P s (t) represents the active power output value of the new energy power generation unit at the current time t; P fΔt represents the transmission capacity of the high-voltage direct current (HVDC) grid in the HVDC transmission system; N represents the total number of new energy power generation units; and Δt represents the time required to determine a permanent fault in the HVDC transmission system.

[0176] Specifically, the adjustment module is used for:

[0177] If the new energy power generation unit is a doubly-fed wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0178]

[0179] In the formula, K d T is the proportional coefficient of the inner current loop for doubly-fed wind turbines. d i is the integral time constant of the inner loop current of the doubly-fed wind turbine; rd_ref (x) represents the actual d-axis current output value of the rotor-side current control loop of the doubly-fed wind turbine before it participates in regulation at time x; i rd (x) represents the d-axis current of the rotor-side current control loop of the doubly-fed wind turbine at time x; α represents the induction coefficient of the doubly-fed wind turbine; and s represents the Laplace operator.

[0180] The d-axis current i of the rotor-side current control loop of the doubly-fed wind turbine at time x is determined by the following formula. rd (x):

[0181]

[0182] In the formula, K p T is the power outer ring proportional coefficient of the doubly-fed wind turbine; p P is the power outer loop integral time constant of the doubly-fed wind turbine; ref (x) represents the reference value of active power of the doubly-fed wind turbine at time x; P gen (x) represents the actual active power output of the doubly fed wind turbine unit before it participates in regulation at time x;

[0183] The induction coefficient α of the doubly-fed wind turbine is determined by the following formula:

[0184]

[0185] In the formula, L s For the stator self-inductance of a doubly-fed wind turbine; L r For the self-inductance of the doubly-fed wind turbine rotor; L m The mutual inductance between the stator and rotor of a doubly-fed wind turbine;

[0186] If the new energy power generation unit is a direct-drive wind turbine power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0187]

[0188] In the formula, K dz T is the current inner loop proportional coefficient for direct-drive wind turbines; dz The current inner loop integral time constant of the direct-drive wind turbine; This is the d-axis current reference value for the current control loop of the direct-drive wind turbine at time x. This represents the actual d-axis current output value of the direct-drive wind turbine before it participates in the current control circuit at time x, before it is regulated.

[0189] The d-axis current reference value of the current control loop of the direct-drive wind turbine at time x is determined by the following formula.

[0190]

[0191] In the formula, P meas-z (x) represents the actual active power output of the direct-drive wind turbine before it participates in regulation at time x; T pz K represents the power outer loop integral time constant of a direct-drive wind turbine; pz This is the power outer ring proportional coefficient for direct-drive wind turbine units;

[0192] If the new energy power generation unit is a photovoltaic power generation unit, then the active power P of the new energy power generation unit at time x is adjusted according to the following formula. G (x):

[0193]

[0194] In the formula, K dg T is the current inner loop proportionality coefficient of the photovoltaic power generation unit; dg Let be the time constant of the inner loop current of the photovoltaic power generation unit; This is the d-axis current reference value for the current control loop of the photovoltaic power generation unit at time x; This represents the actual d-axis current output value of the current control loop of the photovoltaic power generation unit before it participates in regulation at time x.

[0195] The d-axis current reference value of the current control loop of the photovoltaic power generation unit at time x is determined by the following formula.

[0196]

[0197] In the formula, P meas-g(x) represents the actual active power output of the photovoltaic power generation unit before it participates in regulation at time x; T pg K represents the power outer-loop integral time constant of the photovoltaic power generation unit; pg This refers to the power outer loop ratio coefficient of the photovoltaic power generation unit. Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0198] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0199] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0200] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0201] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A direct current fault-based power control method for a new energy power generation unit, characterized in that, The method comprises: detecting a fault mode of a high-voltage direct-current power transmission system; determining an active power reference value of a new energy power generation unit according to the fault mode of the high-voltage direct-current power transmission system; adjusting the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit; the determining of the active power reference value of the new energy power generation unit according to the fault mode of the high-voltage direct-current power transmission system comprises: If the current moment The fault mode of the high-voltage direct-current power transmission system is not fault, the current moment The fault mode of the high-voltage direct-current power transmission system is different from the previous moment of the current moment to The moment, the active power reference value of the new energy power generation unit is adjusted at The moment ; If the current time The fault modes of the high-voltage direct current transmission system are permanent single-pole blocking faults and current time. With the current moment The fault modes of the high-voltage direct current transmission system were different at the previous moment and from the current moment to If the fault modes of the high-voltage direct current transmission system are the same at any given time, then... Continuously adjust the active power reference value of the new energy power generation unit. ; If the current time The fault mode of the high-voltage direct-current power transmission system is a permanent bipolar blocking fault, the current time is different from the fault mode of the high-voltage direct-current power transmission system at the previous time of the current time and is the same as the fault mode of the high-voltage direct-current power transmission system from the current time to the time , the active power reference value of the new energy power generation unit is adjusted at the time ; wherein, is the current time an active power output value of the new energy power generation unit; is the transmission capacity of the high-voltage direct-current power grid in the high-voltage direct-current power transmission system; is the total number of new energy power generation units; is the high-voltage direct-current power transmission system permanent fault determination time; the adjusting of the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit comprises: If the new energy power generation unit is a doubly-fed wind turbine generator unit, the active power of the new energy power generation unit is adjusted according to the following formula t : In the formula, is a current inner loop proportional coefficient of the doubly-fed wind turbine; is a current inner loop integral time constant of the doubly-fed wind turbine; is a rotor-side current control link of the doubly-fed wind turbine before the time when the doubly-fed wind turbine does not participate in regulation; is an actual output value of the shaft current; is a rotor-side current control link of the doubly-fed wind turbine at the time ; is a shaft current of the doubly-fed wind turbine; is an inductance coefficient of the doubly-fed wind turbine; is a Laplace operator; wherein the rotor-side current control loop of the doubly-fed wind turbine at the time instant t is determined by the following equation : Irotor(t) = Irotor(t - Δt) + Kp * (Iref(t) - Irotor(t - Δt)) + Ki * ∫(Iref(t) - Irotor(t - Δt))dt shaft current In the formula, is a power outer loop proportional coefficient of the doubly-fed wind turbine; is a power outer loop integral time constant of the doubly-fed wind turbine; is an active power reference value of the doubly-fed wind turbine corresponding to the time ; is an actual output value of the active power of the doubly-fed wind turbine before participating in regulation at the time ; The induction factor of the doubly-fed wind power unit is determined by the following formula : wherein is the stator self-inductance of the doubly-fed wind turbine; is the rotor self-inductance of the doubly-fed wind turbine; is the mutual inductance of the stator and rotor of the doubly-fed wind turbine; If the new energy power generation unit is a direct-drive wind turbine generator unit, the active power of the new energy power generation unit is adjusted according to the following formula t: time : In the formula, is a current inner loop proportional coefficient of the direct-drive wind turbine; is a current inner loop integral time constant of the direct-drive wind turbine; is a d-axis current reference value of the current control link of the direct-drive wind turbine at the moment of ; is a d-axis current actual output value of the current control link of the direct-drive wind turbine before participating in the adjustment at the moment of ; The d-axis current reference value of the current control link of the direct- driven wind turbine at the moment is determined as follows ​ In the formula, is the actual output value of the active power before the direct-drive wind turbine participates in the regulation at the moment; is the actual output value of the active power before the direct-drive wind turbine participates in the regulation at the moment; is the power outer loop integral time constant of the direct-drive wind turbine; is the power outer loop proportional coefficient of the direct-drive wind turbine; If the new energy power generation unit is a photovoltaic power generation unit, the active power of the new energy power generation unit is adjusted according to the following formula t: time : In the formula, This is the current inner loop proportional coefficient for the photovoltaic power generation unit; Let be the time constant of the inner loop current of the photovoltaic power generation unit; For photovoltaic power generation units in The d-axis current reference value of the current control loop at any given time; For photovoltaic power generation units in The actual output value of the d-axis current of the current control loop before it participates in the adjustment; The d-axis current reference value of the current control link of the photovoltaic power generation unit at the moment is determined according to the following formula Irefd = Irefd0 + Kp (Id - Id0) + Ki (Id - Id0) dt In the formula, is the actual output value of the active power before the participation of the photovoltaic power generation unit in the regulation at the moment; is the actual output value of the active power before the participation of the photovoltaic power generation unit in the regulation at the moment; is the power outer loop integral time constant of the photovoltaic power generation unit; is the power outer loop proportional coefficient of the photovoltaic power generation unit.

2. The method of claim 1, wherein, the detecting of the fault mode of the high-voltage direct-current power transmission system comprises: When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is no fault. When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is a permanent positive pole blocking fault. When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is a permanent negative pole blocking fault. When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is a permanent bipolar blocking fault. The permanent single-pole blocking fault includes a permanent negative-pole blocking fault and a permanent positive-pole blocking fault. The absolute value of the rated DC voltage of the high-voltage DC power grid in the high-voltage DC power transmission system.

3. A direct current fault based power control system for a new energy power generation unit, characterized in that, the system comprises: a detection module, configured to detect a fault mode of a high-voltage direct-current power transmission system; a determination module, configured to determine an active power reference value of a new energy power generation unit according to the fault mode of the high-voltage direct-current power transmission system; an adjustment module, configured to adjust the active power of the new energy power generation unit according to the active power reference value of the new energy power generation unit; the determination module is configured to: If the current time The fault mode of the high-voltage direct-current power transmission system is not fault, the current time Different from the fault mode of the high-voltage direct-current power transmission system at the previous time of the current time to of the current time Adjust the active power reference value of the new energy power generation unit at ; If the current time The fault mode of the high-voltage direct-current power transmission system is a permanent single-pole blocking fault, the current time is different from the fault mode of the high-voltage direct-current power transmission system at the previous time of the current time and is the same as the fault mode of the high-voltage direct-current power transmission system from the current time to the time , the active power reference value of the new energy power generation unit is adjusted at the time ; If the current time The fault mode of the high-voltage direct-current power transmission system is a permanent bipolar blocking fault, the current time is different from the fault mode of the high-voltage direct-current power transmission system at the previous time of the current time and is the same as the fault mode of the high-voltage direct-current power transmission system from the current time to the time , the active power reference value of the new energy power generation unit is adjusted at the time ; wherein, is the current time an active power output value of the new energy power generation unit; is the transmission capacity of the high-voltage direct-current power grid in the high-voltage direct-current power transmission system; is the total number of new energy power generation units; is the permanent fault determination time of the high-voltage direct-current power transmission system; the adjustment module is configured to: If the new energy power generation unit is a doubly-fed wind turbine power generation unit, then adjust according to the following formula. Active power of the new energy power generation unit at any time : In the formula, This is the proportional coefficient of the inner loop current of the doubly-fed wind turbine. The time constant of the inner loop current of the doubly-fed wind turbine generator; For doubly fed wind turbine units The rotor-side current control loop that did not participate in the regulation at any time Actual output value of shaft current; For doubly fed wind turbine units Rotor-side current control loop at all times shaft current; The induction coefficient of the doubly-fed wind turbine; For the Laplace operator; wherein the rotor-side current control loop of the doubly-fed wind turbine at the moment t is determined by the following equation shaft current : In the formula, This is the power outer ring proportional coefficient of the doubly-fed wind turbine unit; The power outer loop integral time constant of the doubly-fed wind turbine; For doubly fed wind turbine units The reference value of active power at any given time; For doubly fed wind turbine units The actual output value of active power before it was adjusted; The induction factor of the doubly-fed wind power unit is determined by the following formula : wherein is the stator self-inductance of the doubly-fed wind turbine; is the rotor self-inductance of the doubly-fed wind turbine; is the mutual inductance of the stator and rotor of the doubly-fed wind turbine; If the new energy power generation unit is a direct-drive wind turbine generator unit, the active power of the new energy power generation unit is adjusted according to the following formula t: time : In the formula, This is the current inner loop proportional coefficient for direct-drive wind turbine generators; The current inner loop integral time constant of the direct-drive wind turbine; For direct-drive wind turbines in The d-axis current reference value of the current control loop at any given time; For direct-drive wind turbines in The actual output value of the d-axis current of the current control loop before it participates in the adjustment; The d-axis current reference value of the current control link of the direct- driven wind turbine at the moment is determined as follows ​ In the formula, is the actual output value of the active power before the direct-drive wind turbine participates in the regulation at the moment; is the actual output value of the active power before the direct-drive wind turbine participates in the regulation at the moment; is the power outer loop integral time constant of the direct-drive wind turbine; is the power outer loop proportional coefficient of the direct-drive wind turbine; If the new energy power generation unit is a photovoltaic power generation unit, the active power of the new energy power generation unit is adjusted according to the following formula t: time : In the formula, This is the current inner loop proportional coefficient for the photovoltaic power generation unit; Let be the time constant of the inner loop current of the photovoltaic power generation unit; For photovoltaic power generation units in The d-axis current reference value of the current control loop at any given time; For photovoltaic power generation units in The actual output value of the d-axis current of the current control loop before it participates in the adjustment; The d-axis current reference value of the current control link of the photovoltaic power generation unit at the moment is determined according to the following formula Irefd = Irefd0 + Kp (Id - Id0) + Ki (Id - Id0) dt In the formula, is the actual output value of the active power before the participation of the photovoltaic power generation unit in the regulation at the moment; is the actual output value of the active power before the participation of the photovoltaic power generation unit in the regulation at the moment; is the power outer loop integral time constant of the photovoltaic power generation unit; is the power outer loop proportional coefficient of the photovoltaic power generation unit.

4. The system of claim 3, wherein, the detection module is configured to: When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is no fault. When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is a permanent positive pole blocking fault. When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is a permanent negative pole blocking fault. When the absolute value of the positive direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies and the absolute value of the negative direct current voltage of the high-voltage direct current power grid at the current time in the high-voltage direct current transmission system satisfies , then the fault mode of the high-voltage direct current transmission system at the current time is a permanent bipolar blocking fault. The permanent single-pole blocking fault includes a permanent negative-pole blocking fault and a permanent positive-pole blocking fault. The absolute value of the rated DC voltage of the high-voltage DC power grid in the high-voltage DC power transmission system.

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