CN108233409B - Fault ride-through control method and system for new energy island flexible direct delivery system - Google Patents
Fault ride-through control method and system for new energy island flexible direct delivery system Download PDFInfo
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- CN108233409B CN108233409B CN201711389634.0A CN201711389634A CN108233409B CN 108233409 B CN108233409 B CN 108233409B CN 201711389634 A CN201711389634 A CN 201711389634A CN 108233409 B CN108233409 B CN 108233409B
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- H02J3/386—
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
Abstract
A fault ride-through control method and system for a new energy island flexible direct delivery system comprise the following steps: when the flexible direct current power grid fails: the flexible direct current converter station sends a control signal to the energy storage equipment according to the detected fault type; the energy storage equipment performs power control according to the control signal; after the fault of the flexible direct current power grid is cleared: the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid; the new energy power station controls whether the wind turbine generator is cut off or not according to the active control signal; and the energy storage equipment controls the active power sent out according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid, so as to complete fault ride-through. According to the technical scheme, the rapid control of power is realized, and after fault recovery, the protection and the removal of surplus wind power are started according to the refined control requirement, so that the crossing is completed.
Description
Technical Field
The application relates to the technical field of new energy fault ride-through control of island delivery, in particular to a fault ride-through control method and system of a new energy island flexible direct delivery system.
Background
The traditional large-scale wind power long-distance transmission, whether the traditional LCC type direct current or alternating current is adopted, needs a strong synchronous power supply support at a transmitting end, and sometimes needs to provide support even at a receiving end. And with the national energy strategy transformation, the difficulty lies in developing wind power and simultaneously matching with the development of the traditional synchronous power supply. Aiming at a ms-level control wind turbine, an island is difficult to respond to related control requirements in time when connected with a flexible direct current power grid, particularly when a direct current power grid breaks down and cuts off partial direct current lines, wind power injected into the flexible direct current system needs to be limited rapidly, and the power control and protection switching scheme of the conventional wind turbine are difficult to meet the requirements of accurate power reduction control of 6-8 ms. In addition, the active power injected into the converter station is controlled by adopting the energy consumption device arranged on the alternating-current side bus of the flexible direct-current converter station, so that the loss of wind power during faults can be caused, and the wind power consumption can be influenced.
For this reason, the adoption of flexible direct grid delivery is based on the situation that will be one of the hot spots and alternative development schemes for research. Aiming at how to ensure that an island connected wind turbine generator achieves fault ride-through after a flexible direct current power grid breaks down, the application provides a method for coordinating a flexible direct current converter station with a machine-side super capacitor energy storage device.
Disclosure of Invention
In order to solve the defects in the prior art, the application provides a fault ride-through control method and system for a new energy island flexible and straight delivery system.
The technical scheme provided by the application is as follows:
a fault ride-through control method of a new energy island flexible direct delivery system comprises the following steps:
when the flexible direct current power grid fails:
the flexible direct current converter station sends a control signal to the energy storage equipment according to the detected fault type;
the energy storage equipment performs power control according to the control signal;
after the fault of the flexible direct current power grid is cleared:
the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid;
the new energy power station controls whether the wind turbine generator is cut off or not according to the active control signal;
and the energy storage equipment controls the active power sent out according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid, so as to complete fault ride-through.
Preferably, the fault types include monopolar faults and bipolar faults;
the monopolar fault, comprising: voltage drop of direct current bus of single-pole converter station;
the bipolar failure, comprising: the voltage of the direct current bus of the bipolar converter station drops.
Preferably, the flexible dc converter station sends a control signal to the energy storage device according to the detected fault type, including:
when the flexible direct current converter station detects a single pole fault, the flexible direct current converter station transmits an active power control signal to an energy storage device, the active power control signal comprising: the upper limit value of the total wind power output is half of the conveying capacity of the flexible direct current power grid;
when the flexible direct current converter station detects a bipolar fault, the flexible direct current converter station transmits an active power control signal to an energy storage device, the active power control signal comprising: the upper limit value of the total wind power output is 0.
Preferably, the energy storage device performs power control according to the control signal, including:
the energy storage equipment judges the conveying capacity of the flexible direct current power grid according to the detected fault types, determines the upper limit value of the output of the wind turbine generator under different fault types by combining the number of the wind turbine generator, and calculates the absorbed active power according to the following formula:
wherein P is se : an active power value that the energy storage device should absorb; p (P) 0 : the actual output value of the wind turbine generator before failure; p (P) lim : calculating according to the capacity of the flexible direct current power grid and the number of wind turbine generatorsAnd obtaining the upper limit value of the output of the wind turbine under different fault conditions.
Preferably, the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid, and the method comprises the following steps:
after the monopole faults of the flexible direct current power grid are cleared, the fault pole is recovered to operate or the fault pole cannot be recovered to operate;
and after the bipolar faults of the flexible direct current power grid are cleared, the bipolar operation is recovered, and the bipolar operation is recovered or the bipolar operation cannot be recovered.
Preferably, the new energy power station controls whether the wind turbine generator is cut off according to the active control signal, including:
when the fault pole is recovered to run, keeping the wind power output before the fault; the method comprises the steps of carrying out a first treatment on the surface of the
And when the fault pole can not be recovered to operate, judging and cutting off the number of the wind turbine generators.
Preferably, when the fault pole cannot be recovered to operate, judging and cutting off the number of the wind turbine generator sets includes:
when a monopole fails, the fault pole cannot recover to operate, and the number of the wind turbine generators is judged and cut off;
and when the bipolar fault occurs, judging and cutting off the number of the wind turbine generator sets according to the fact that the operation is recovered by the single pole or the operation cannot be recovered by the double pole.
Preferably, when a monopole fails, the failure pole cannot resume operation, and judging and cutting off the number of wind turbine generators includes:
when the wind power output before failure is lower than or equal to half of the rated transmission capacity of the flexible direct current power grid, the new energy power station does not need to cut off the wind turbine generator;
when the wind power output before failure is higher than half of the rated transmission capacity of the flexible direct current power grid, the new energy power station cuts off the corresponding wind power generation set.
Preferably, when the bipolar fault occurs, judging that the number of the wind turbine generator sets is cut off according to the fact that the monopolar operation is recovered or the bipolar operation cannot be recovered comprises:
the monopole recovery operation comprises that when the wind power output before failure is less than or equal to half of the rated transmission capacity of the flexible direct current power grid, the wind power plant does not need to cut off the wind power generation set; when the wind power output before failure is greater than half of the rated transmission capacity of the flexible direct current power grid, the new energy power station cuts off the corresponding number of wind power units;
the bipolar operation can not be recovered, the upper limit of the total wind power output of the new energy power station is 0, and all wind power units need to be cut off by the new energy power station.
Preferably, the energy storage device controls the active power sent out according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid, and calculates the active power value allowed to be sent out by the energy storage device after the fault according to the following formula:
wherein P is seo : allowing an active power value sent by the energy storage equipment after the fault; p (P) 0a : the actual output value of the wind turbine after the failure; p (P) lima : calculating the output upper limit value of the wind turbine according to the transmission capacity of the flexible direct current power grid after the fault and the number of the wind turbine running in a grid connection mode after the fault; Σp 0a : total wind power output after failure; p (P) DClim : and the flexible direct current power grid conveying capacity after failure.
Another object of the present application is to provide a fault ride-through control system for a new energy island flexible and direct delivery system, including: the system comprises a fault detection module, a fault coping module, a recovery control module, a removal coping module and a fault traversing module;
the fault detection module is used for when the flexible direct current power grid breaks down:
the flexible direct current converter station sends a control signal to the energy storage equipment according to the detected fault type;
the fault coping module is used for controlling the power of the energy storage equipment according to the control signal;
the recovery control module is used for, after the fault of the flexible direct current power grid is cleared:
the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid;
the cutting-off coping module is used for controlling whether the wind turbine generator is cut off or not by the new energy power station according to the active control signal;
the fault ride-through module is used for controlling the active power sent by the energy storage equipment according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid to complete fault ride-through.
Preferably, the fault detection module includes: a detection sub-module and a transmission sub-module;
the detection submodule is used for detecting the fault type of the flexible direct current converter station;
and the transmitting submodule is used for transmitting an active power control signal to the energy storage equipment according to the fault type.
Preferably, the fault handling module comprises an absorption sub-module;
the absorption submodule is used for judging the conveying capacity of the flexible direct current power grid according to the detected fault type by the energy storage equipment, determining the upper limit value of the output of the wind turbine under different fault types by combining the number of the wind turbine, and determining the absorbed active power.
Preferably, the recovery control module includes: the sub-module is identified and the sub-module,
and the identification sub-module is used for identifying the recovery condition of the fault pole after the fault of the flexible direct current power grid is cleared.
Compared with the closest prior art, the technical scheme provided by the application has the following beneficial effects:
according to the technical scheme, when the flexible direct current power grid breaks down and needs to limit the injected power, an active power control signal is sent out, the super capacitor arranged at the motor end of the wind turbine generator is used for starting power storage, so that rapid power adjustment is realized, after the fault is recovered, whether part of the wind turbine generator needs to be cut off is judged according to the limit requirement of the transmission capacity of the flexible direct current power grid, the wind power output is ensured not to exceed the transmission capacity of the flexible direct current power grid, and the active power stored in the energy storage equipment is timely sent out on the premise that the flexible direct current power grid does not run in an overload mode, so that fault crossing is completed.
According to the technical scheme, wind power is directly connected into the flexible direct current power grid through alternating current collection without being connected with a main network, and active power output can be adjusted according to the fact that wind power cannot timely track the change of the conveying capacity of the flexible direct current power grid after faults, and the risk that the power injected into the flexible direct current power grid is excessive, so that the flexible direct current power grid is overloaded and quits operation is likely to be caused.
Drawings
Fig. 1 is a flow of a fault ride-through control method of a new energy island flexible direct delivery system based on coordination of a flexible direct current converter station and a machine-side super capacitor energy storage device;
fig. 2 is a schematic diagram of wind power access flexible direct current power grid with super capacitor at the machine end.
Detailed Description
For a better understanding of the present application, reference is made to the following description, drawings and examples.
Wind power is directly connected into a flexible direct-current power grid through alternating-current collection without being connected with a main network and direct-current conversion, synchronous power supply support is not needed, flexibility of wind power grid connection is improved, but the problem of control coordination between flexible direct-current ms-level control and wind power also exists, and when wind power cannot timely react to power change, excessive power injected into the direct-current power grid can possibly be caused, and accordingly the whole converter station is blocked and exits. The active power injected into the converter station is controlled by adopting the energy consumption device arranged on the alternating-current side bus of the flexible direct-current converter station, so that the loss of wind power during faults can be caused, and the wind power consumption can be influenced.
Aiming at the problems that the flexible direct current power grid breaks down and the power injected into the converter station is required to be controlled within ms, and the wind turbine generator is difficult to respond in time, on the premise of reducing wind power loss caused by faults as much as possible, the fault ride-through control method of the new energy island flexible direct current delivery system based on coordination of the flexible direct current converter station and the super capacitor energy storage equipment at the machine end is provided, namely when the direct current power grid breaks down and needs to limit the injected power, a control signal is sent, the super capacitor arranged at the machine end of the wind turbine generator starts power storage, the rapid control of the power is realized, the active power injected into the flexible direct current converter station is reduced, the overload operation of the flexible direct current power grid is avoided, the delivery capacity of the flexible direct current power grid is judged according to the recovery condition of the flexible direct current converter station, whether surplus wind power needs to be cut off is determined, so that the wind power does not exceed the delivery capacity of the flexible direct current power grid is ensured, and the whole ride-through is realized.
A schematic diagram of wind power access flexible direct current power grid with the super capacitor arranged at the machine end is shown in fig. 2.
Super-capacitors are an electrochemical element that stores energy by polarizing an electrolyte. It is different from traditional chemical power supply, is a power supply with special performance between traditional capacitor and battery, and mainly relies on electric double layer and redox false capacitance charge to store electric energy. The basic principle is that the electric double layer structure composed of active carbon porous electrode and electrolyte is utilized to obtain super-large capacity as other kinds of electric double layer capacitors. The outstanding advantages are high power density, short charge and discharge time, long cycle life and wide working temperature range. Supercapacitors can be considered as two non-reactive porous electrode plates suspended in an electrolyte, powered on, positive plates attracting negative ions in the electrolyte, negative plates attracting positive ions, in effect forming two capacitive storage layers, separated positive ions near the negative plates, and negative ions near the positive plates. The supercapacitor stores energy in the separated charges, and the larger the area for storing the charges is, the denser the separated charges are, and the larger the capacitance is. The area of a conventional capacitor is the planar area of the conductor, which is made in long rolls in order to obtain a large capacity, sometimes with special tissue structures to increase its surface area. Conventional capacitors are formed by separating their two plates with an insulating material, typically plastic film, paper, etc., which is typically required to be as thin as possible. The area of the supercapacitor is based on a porous carbon material, the porous structure of which allows its area to reach 2000m 2 By means of several measures, a larger surface area can be achieved. The distance separating the supercapacitor charge is determined by the size of the electrolyte ions attracted to the charged electrode. This distance is equal to the distance that can be achieved with conventional capacitor film materialsThe separation is smaller. The large surface area combined with the very small charge separation distance makes supercapacitors a surprisingly large electrostatic capacity than conventional capacitors, which is also the "super" location.
The application provides a fault ride-through control method of a new energy island flexible direct-delivery system based on coordination of a flexible direct-current converter station and a machine-side super-capacitor energy storage device, and the flow is shown in a figure 1.
A fault ride-through control method of a new energy island flexible direct delivery system comprises the following steps:
when the flexible direct current power grid fails:
the flexible direct current converter station sends a control signal to the energy storage equipment according to the detected fault type;
the energy storage equipment performs power control according to the control signal;
after the fault of the flexible direct current power grid is cleared:
the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid;
the new energy power station controls whether the wind turbine generator is cut off or not according to the active control signal;
and the energy storage equipment controls the active power sent out according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid, so as to complete fault ride-through.
In particular, the method comprises the steps of,
I. after the flexible direct current power grid fails, the flexible direct current converter station senses the falling of direct current voltage, and the flexible direct current converter station sends a control signal to the energy storage equipment;
II. During the fault period, the energy storage equipment performs power control according to the control signal;
III, the flexible direct current power grid protection element acts to clear faults, and after the flexible direct current power grid resumes operation, the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid;
and IV, the energy storage equipment participates in an active power control system of the new energy power station, and takes the actual output level of the new energy power station into consideration, and on the premise that the transmission capacity of the flexible direct current power grid is not exceeded, the energy storage equipment releases active power to complete crossing.
Further, in the step I:
when the flexible direct current power grid fails, the direct current voltage of the flexible direct current power grid drops, at the moment, the flexible direct current converter station senses the direct current voltage drop, judges the failure condition and sends an active power control signal to the energy storage equipment through the communication system.
Specifically, when the flexible direct current power grid breaks down, the fault condition is judged according to the detected direct current bus voltage of the bipolar converter station, when the direct current bus voltage of the unipolar converter station drops, the fault condition is confirmed to be a unipolar fault, the other pole can normally operate, the conveying capacity of the flexible direct current power grid is reduced to half of the original conveying capacity, and at the moment, the flexible direct current converter station sends an active power control signal to the energy storage equipment: the upper limit value of the total wind power output is half of the conveying capacity of the flexible direct current power grid; when the voltage of the direct current bus of the bipolar converter station drops, confirming that the fault condition is a bipolar fault, reducing the conveying capacity of the flexible direct current power grid to 0, and sending an active power control signal to the energy storage equipment by the flexible direct current converter station at the moment: the upper limit value of the total wind power output is 0.
Further, in the step II:
and judging the conveying capacity of the flexible direct current power grid in the fault period according to the fault condition, and determining the upper limit value of the output of the wind turbine under different fault conditions by combining the number of the wind turbine. If the flexible direct current power grid conveying capacity is 1000MW in normal operation, 500 2MW wind turbines are connected, and if a single pole fails, the flexible direct current power grid conveying capacity is 500MW in normal operation, and the upper limit of the wind turbine output is 1MW; when the bipolar fault occurs, the transmission capacity of the flexible direct current power grid is 0, and the upper limit of the output of the wind turbine generator is 0. After the energy storage equipment receives the active power control signal, an active control system of the equipment is started, active power control is carried out according to the wind power output value monitored in real time before the fault, and the wind power output is ensured not to exceed the conveying capacity of the flexible direct current power grid in the fault period. The active power control expression of the energy storage device is as follows.
Wherein P is se : an active power value that the energy storage device should absorb; p (P) 0 : the actual output value of the wind turbine generator before failure; p (P) lim : and calculating the output upper limit value of the wind turbine under different fault conditions according to the capacity of the flexible direct current power grid and the number of the wind turbine.
When the flexible direct current power grid has a single-pole fault, after receiving an active power control signal that the upper limit value of the wind power output is half of the transmission capacity of the flexible direct current power grid, and combining the upper limit value of the wind power generation set during the single-pole fault, calculating the active power which the energy storage equipment should absorb, and when the wind power generation set output before the fault is lower than the upper limit value of the wind power generation set output, the energy storage equipment does not act, namely the absorbed active power is 0; when the output of the wind turbine before the fault is higher than the upper limit value of the output of the wind turbine, the energy storage device acts to absorb active power, and the absorbed power value is the difference value between the output of the wind turbine before the fault and the limit value of the output of the wind turbine during the fault.
Further, in the step III:
after the flexible direct current power grid protection element acts to clear the fault, the flexible direct current converter station judges the conveying capacity of the flexible direct current power grid after the fault according to the recovery condition of the flexible direct current power grid, and then sends an active power control signal to the new energy power station, and the new energy power station judges whether to cut off part of wind turbine generator sets according to the wind power output monitored in real time before the fault and the active power control signal so as to ensure that the upper limit of the wind power output does not exceed the conveying capacity of the flexible direct current power grid after the fault.
When the flexible direct current power grid has a monopole fault and clears the fault, if the fault pole resumes operation, the flexible direct current power grid conveying capacity resumes to a rated level, the flexible direct current converter station sends an active power control signal to the new energy power station, the upper limit value of the total wind power output of the new energy power station is the rated conveying capacity of the flexible direct current power grid, the new energy power station does not need to adjust active power output, and the output level before the fault is maintained; when the flexible direct current power grid fails in a single-pole mode and clears the fault, if the fault cannot be recovered and the flexible direct current power grid exits the operation, the transmission capacity of the flexible direct current power grid is reduced to half of the rated transmission capacity of the flexible direct current power grid, the flexible direct current converter station sends an active power control signal to the new energy power station, the upper limit value of the total wind power output of the new energy power station is reduced to half of the rated transmission capacity of the flexible direct current power grid, the new energy power station judges the number of wind power units to be cut off based on the wind power output monitored in real time before the fault by combining the active power control signal, when the wind power output before the fault is lower than or equal to half of the rated transmission capacity of the flexible direct current power grid, the new energy power station does not need to cut off the wind power units, and when the wind power output before the fault is greater than half of the rated transmission capacity of the flexible direct current power grid, the wind power units needing to be cut off are calculated, and the wind power units with corresponding numbers are cut off forcibly, so that the wind power output does not exceed half of the rated transmission capacity of the flexible direct current power grid.
When the flexible direct current power grid has bipolar faults and eliminates the faults, if the bipolar faults are restored to operate, the transmission capacity of the flexible direct current power grid is restored to the rated level, the flexible direct current converter station sends an active power control signal to the new energy power station, the upper limit value of the total wind power output of the new energy power station is the rated transmission capacity of the flexible direct current power grid, the new energy power station does not need to adjust the active power output, and the output level before the faults is maintained; when the flexible direct current power grid has bipolar faults and eliminates the faults, if the other pole cannot be recovered to exit the operation after the bipolar faults are recovered, the flexible direct current power grid conveying capacity is reduced to half of the flexible direct current power grid rated conveying capacity, the flexible direct current converter station sends an active power control signal to the new energy power station, the upper limit value of the total wind power output of the new energy power station is reduced to half of the flexible direct current power grid rated conveying capacity, the new energy power station judges the number of wind power units to be cut off based on the wind power output monitored in real time before the faults by combining the active power control signal, when the wind power output before the faults is lower than or equal to half of the flexible direct current power grid rated conveying capacity, the new energy power station does not need to cut off the wind power units, when the wind power output before the faults is greater than half of the flexible direct current power grid rated conveying capacity, the new energy power station calculates the number of wind power units to be cut off, and cuts off the wind power units corresponding to force the number of the wind power units to ensure that the wind power output does not exceed half of the flexible direct current power grid rated conveying capacity. When the flexible direct current power grid fails in bipolar mode and eliminates the fault, if the bipolar mode cannot be recovered and the flexible direct current power grid exits the operation, the flexible direct current power grid sends an active power control signal to the new energy power station, the upper limit value of the total wind power output of the new energy power station is 0, and all wind power units need to be cut off by the new energy power station.
Further, in the step IV:
after the new energy power station completes active power control, the energy storage device judges the limit value of the active power which can be sent out by the energy storage device according to the transmission capacity of the flexible direct current power grid after the fault and the output level of the new energy power station, and takes the sum of the output of the new energy and the active power sent out by the energy storage device not exceeding the transmission capacity of the flexible direct current power grid as constraint, and combines the active power stored in the energy storage device to timely send out the active power stored in the energy storage device until the energy storage device sends out all the stored active power, and the energy storage device is restored to an idle state, so that preparation is made for the next fault crossing.
And determining the upper limit value of the output of the wind turbine after the fault according to the conveying capacity of the flexible direct current power grid after the fault and combining the number of the wind turbine running in a grid connection mode after the fault. The energy storage equipment judges the active power limit value which can be sent out based on the upper limit of the output of the wind turbine and the real-time monitored actual output value of the wind turbine. If the transmission capacity of the flexible direct current power grid is 1000MW, 500 2MW wind turbines are connected, the output of each wind turbine is 0.8MW, when the total output of a new energy power station before failure is 400MW, when a monopole failure is detected, the operation is not recovered after the failure is cleared, and the other pole is in normal operation, the transmission capacity of the flexible direct current power grid after the failure is 500MW, the total output of new energy after the failure is cleared does not exceed the transmission capacity of the flexible direct current power grid, the number of grid-connected operation fans is 500 without cutting off the wind turbines, the upper limit of the output of the wind turbines is 1MW, and the upper limit of the active power output of energy storage equipment is 0.2MW; if the wind power output before the fault is 600MW, the number of wind power sets in grid-connected operation is 500, the output of each wind power set is 1.2MW, the single-pole fault is removed and the operation is not recovered after the fault is cleared, and when the other pole is in normal operation, the flexible direct current power grid conveying capacity after the fault is 500MW, and the total output of new energy after the fault is cleared exceeds the flexible direct current power grid conveying capacity, so that the new energy power station needs to cut off the output of 100MW wind power sets, the output of each wind power set is considered to be 1.2MW, the number of the folded wind power sets is 83.3, the number of wind power sets needs to be cut off to be 84, the number of wind power sets in grid-connected operation after the fault is 416, the upper limit of the wind power sets is 1.2MW at the moment, the actual output of each wind power set is 1.2MW, and the energy storage equipment cannot generate active power.
The active power control expression and constraints issued by the energy storage device are shown below.
Wherein P is seo : allowing an active power value sent by the energy storage equipment after the fault; p (P) 0a : the actual output value of the wind turbine after the failure; p (P) lima : calculating the output upper limit value of the wind turbine according to the transmission capacity of the flexible direct current power grid after the fault and the number of the wind turbine running in a grid connection mode after the fault; Σp 0a : total wind power output after failure; p (P) DClim : and the flexible direct current power grid conveying capacity after failure.
On the premise that the sum of the output of the new energy power station and the active output of the energy storage device does not exceed the transmission capacity of the flexible direct current power grid, the energy storage device sends out active power according to the calculated active power output limit value until the energy storage device sends out all the stored active power, and the energy storage device is restored to an idle state and is ready for the next fault ride through.
Another object of the present application is to provide a fault ride-through control system for a new energy island flexible and direct delivery system, including: the system comprises a fault detection module, a fault coping module, a recovery control module, a removal coping module and a fault traversing module;
the five modules described above are further explained below:
the fault detection module is used for when the flexible direct current power grid breaks down:
the flexible direct current converter station sends a control signal to the energy storage equipment according to the detected fault type;
the fault coping module is used for controlling the power of the energy storage equipment according to the control signal;
and the recovery control module is used for after the fault of the flexible direct current power grid is cleared:
the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid;
the cutting-off coping module is used for controlling whether the wind turbine generator is cut off or not by the new energy power station according to the active control signal;
and the fault ride-through module is used for controlling the active power sent by the energy storage equipment according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid to complete fault ride-through.
A fault detection module comprising: a detection sub-module and a transmission sub-module;
the detection submodule is used for detecting the fault type of the flexible direct current converter station;
and the transmitting submodule is used for transmitting an active power control signal to the energy storage equipment according to the fault type.
The fault handling module comprises an absorption sub-module;
and the absorption sub-module is used for judging the conveying capacity of the flexible direct current power grid according to the detected fault type by the energy storage equipment, combining the number of the wind turbine generators, determining the upper limit value of the output of the wind turbine generators under different fault types, and determining the absorbed active power.
A recovery control module comprising: the sub-module is identified and the sub-module,
and the identification sub-module is used for identifying the recovery condition of the fault pole after the fault of the flexible direct current power grid is cleared.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may 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, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing is illustrative of the present application and is not to be construed as limiting thereof, but rather as providing for the use of additional embodiments and advantages of all such modifications, equivalents, improvements and similar to the present application are intended to be included within the scope of the present application as defined by the appended claims.
Claims (10)
1. The fault ride-through control method of the new energy island flexible direct delivery system is characterized by comprising the following steps of: when the flexible direct current power grid fails:
the flexible direct current converter station sends a control signal to the energy storage equipment according to the detected fault type;
the energy storage equipment performs power control according to the control signal;
after the fault of the flexible direct current power grid is cleared:
the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid;
the new energy power station controls whether the wind turbine generator is cut off or not according to the active control signal;
the energy storage equipment controls the active power sent out according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid, and fault ride-through is completed;
the fault type includes: monopolar faults and bipolar faults;
the monopolar fault, comprising: voltage drop of direct current bus of single-pole converter station;
the bipolar failure, comprising: the voltage of the direct current bus of the bipolar converter station drops;
the flexible direct current converter station sends a control signal to the energy storage device according to the detected fault type, and the flexible direct current converter station comprises:
when the flexible direct current converter station detects a single pole fault, the flexible direct current converter station transmits an active power control signal to an energy storage device, the active power control signal comprising: the upper limit value of the total wind power output is half of the conveying capacity of the flexible direct current power grid;
when the flexible direct current converter station detects a bipolar fault, the flexible direct current converter station transmits an active power control signal to an energy storage device, the active power control signal comprising: the upper limit value of the total wind power output is 0.
2. The fault ride-through control method of the new energy island flexible direct delivery system according to claim 1, wherein the energy storage device performs power control according to the control signal, and the method comprises the following steps:
the energy storage equipment judges the conveying capacity of the flexible direct current power grid according to the detected fault types, determines the upper limit value of the output of the wind turbine generator under different fault types by combining the number of the wind turbine generator, and calculates the absorbed active power according to the following formula:
wherein P is se : an active power value that the energy storage device should absorb; p (P) 0 : the actual output value of the wind turbine generator before failure; p (P) lim : and calculating the output upper limit value of the wind turbine under different fault conditions according to the capacity of the flexible direct current power grid and the number of the wind turbine.
3. The fault ride-through control method of the new energy island flexible direct delivery system according to claim 1, wherein the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid, comprising:
after the monopole faults of the flexible direct current power grid are cleared, the fault pole is recovered to operate or the fault pole cannot be recovered to operate;
and after the bipolar faults of the flexible direct current power grid are cleared, the bipolar operation is recovered, and the bipolar operation is recovered or the bipolar operation cannot be recovered.
4. The fault ride-through control method of the new energy island flexible direct delivery system according to claim 1, wherein the new energy power station controls whether a wind turbine generator is cut off according to the active control signal, and the method comprises the following steps:
when the fault pole is recovered to run, keeping the wind power output before the fault;
and when the fault pole can not be recovered to operate, judging and cutting off the number of the wind turbine generators.
5. The method for controlling fault ride through of the new energy island flexible direct delivery system according to claim 4, wherein the judging and cutting off the number of wind turbines when the fault pole cannot resume operation comprises:
when a monopole fails, the fault pole cannot recover to operate, and the number of the wind turbine generators is judged and cut off;
and when the bipolar fault occurs, judging and cutting off the number of the wind turbine generator sets according to the fact that the operation is recovered by the single pole or the operation cannot be recovered by the double pole.
6. The fault ride-through control method of the new energy island flexible direct delivery system according to claim 5, wherein when the monopole fails, the fault pole cannot resume operation, and the judging and cutting off the number of wind turbines comprises:
when the wind power output before failure is lower than or equal to half of the rated transmission capacity of the flexible direct current power grid, the new energy power station does not need to cut off the wind turbine generator;
when the wind power output before failure is higher than half of the rated transmission capacity of the flexible direct current power grid, the new energy power station cuts off the corresponding wind power generation set.
7. The fault ride-through control method of the new energy island flexible direct delivery system according to claim 5, wherein when the bipolar fault occurs, judging that the number of wind turbine generator sets is cut off according to that the operation is recovered by a single pole or the operation cannot be recovered by a double pole comprises:
the monopole recovery operation comprises that when the wind power output before failure is less than or equal to half of the rated transmission capacity of the flexible direct current power grid, the wind power plant does not need to cut off the wind power generation set; when the wind power output before failure is greater than half of the rated transmission capacity of the flexible direct current power grid, the new energy power station cuts off the corresponding number of wind power units;
the bipolar operation can not be recovered, the upper limit of the total wind power output of the new energy power station is 0, and all wind power units need to be cut off by the new energy power station.
8. The fault ride-through control method of the new energy island flexible direct delivery system according to claim 1, wherein the energy storage device controls the active power sent out according to the output of the new energy power station after the fault and the delivery capacity of the flexible direct current power grid, and calculates the active power value allowed to be sent out by the energy storage device after the fault according to the following formula:
wherein P is seo : allowing an active power value sent by the energy storage equipment after the fault; p (P) 0a : the actual output value of the wind turbine after the failure; p (P) lima : calculating the output upper limit value of the wind turbine according to the transmission capacity of the flexible direct current power grid after the fault and the number of the wind turbine running in a grid connection mode after the fault; Σp 0a : total wind power output after failure; p (P) DClim : and the flexible direct current power grid conveying capacity after failure.
9. The utility model provides a fault ride-through control system of new forms of energy island gentle straight delivery system which characterized in that includes: the system comprises a fault detection module, a fault coping module, a recovery control module, a removal coping module and a fault traversing module;
the fault detection module is used for when the flexible direct current power grid breaks down:
the flexible direct current converter station sends a control signal to the energy storage equipment according to the detected fault type;
the fault coping module is used for controlling the power of the energy storage equipment according to the control signal;
the recovery control module is used for, after the fault of the flexible direct current power grid is cleared:
the flexible direct current converter station sends an active control signal to the new energy power station according to the recovery condition of the flexible direct current power grid;
the cutting-off coping module is used for controlling whether the wind turbine generator is cut off or not by the new energy power station according to the active control signal;
the fault ride-through module is used for controlling the active power sent by the energy storage equipment according to the output of the new energy power station after the fault and the conveying capacity of the flexible direct current power grid to complete fault ride-through;
the fault detection module comprises: a detection sub-module and a transmission sub-module;
the detection submodule is used for detecting the fault type of the flexible direct current converter station;
the transmitting submodule is used for transmitting an active power control signal to the energy storage equipment according to the fault type;
the fault coping module comprises an absorption sub-module;
the absorption submodule is used for judging the conveying capacity of the flexible direct current power grid according to the detected fault type by the energy storage equipment, determining the upper limit value of the output of the wind turbine under different fault types by combining the number of the wind turbine, and determining the absorbed active power.
10. The fault ride-through control system of the new energy island flexible direct delivery system according to claim 9, wherein the recovery control module comprises: the sub-module is identified and the sub-module,
and the identification sub-module is used for identifying the recovery condition of the fault pole after the fault of the flexible direct current power grid is cleared.
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| CN109659965B (en) * | 2018-11-13 | 2023-01-13 | 许继电气股份有限公司 | Active power control method and system for flexible direct current transmission system |
| CN110460096B (en) * | 2019-08-07 | 2021-12-03 | 国网山东省电力公司电力科学研究院 | Fault ride-through control method and device for new energy island flexible direct-sending system |
| CN113452011B (en) * | 2020-03-25 | 2022-12-02 | 许继电气股份有限公司 | Double-connection transformer offshore wind power direct current sending-out system and control method |
| CN113300405B (en) * | 2021-06-24 | 2022-05-10 | 广东电网有限责任公司 | Island protection method and system with island fault ride-through capability |
| CN113964864A (en) * | 2021-10-19 | 2022-01-21 | 广东电网有限责任公司 | Flexible direct grid-connected system receiving end converter station island fault ride-through control method and system |
| CN114047442B (en) * | 2021-12-27 | 2022-04-26 | 西安德纳检验检测有限公司 | Fault ride-through detection method, device and system for new energy station |
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