CN110011352B - Voltage drop control method containing new energy grid connection - Google Patents
Voltage drop control method containing new energy grid connection Download PDFInfo
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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
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
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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
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
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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
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
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Abstract
The invention provides a voltage drop control method containing new energy grid connection, which comprises the following steps: collecting power grid voltage and power grid current data; judging whether the voltage drops, if so, controlling the system to work in a voltage drop mode: i, switching a frequency converter of a motor of the oil pumping well to a voltage drop mode, namely energy storage and power supply; ii, the wind turbine generator is switched to a voltage drop control mode, namely reactive support, and the compensation reactive power is Q1; iii the energy storage system is switched to a voltage control mode-reactive support and active support; the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter; and when the voltage of the power grid is recovered, the parameter switching of the controller is realized, and the control system works in a multi-energy complementary mode. The invention can meet the requirement of the grid side on low voltage ride through of the wind turbine generator, and can also meet the requirement of reliable power supply of the motor load of the oil pumping well, thereby further improving the reliability of the system.
Description
Technical Field
The invention relates to the technical field of new energy power generation applied to oil fields, in particular to a voltage drop control method containing new energy grid connection.
Background
In an oil field power supply system, power supply for an oil pumping well is mainly achieved by driving a variable frequency main motor. On one hand, at the remote oil pumping well location, the capacity of the traditional power grid is limited, the resistance to voltage disturbance is insufficient, and frequent parking is easily caused; on the other hand, how to reduce energy consumption in oil and gas production and increase income become important. One of the most preferred methods for reducing energy consumption at present is to reduce the cost of the production process by means of a self-generating form, a new energy power generation form such as wind power, energy storage and the like, and peak-valley electricity price, electricity selling and the like.
Wind power generation has been widely used as one of the main new energy power generation forms at present, however, due to the power fluctuation characteristic of wind power generation, the wind power generation cannot be compared with a thermal power generating unit on the occasion of reliable power supply, but if the wind power generation and energy storage are combined for application, the technical advantages can be complemented. The wind driven generator can realize single machine high power, the energy storage can realize the improvement of the quality of electric energy, and simultaneously realize the power supply and the support of the voltage recovery of a power grid during the voltage drop of the power grid. The technology is gradually popularized and demonstrated, and how to successfully apply the technology to an oil field power supply system has important significance.
The control method of the voltage drop is one of key technologies for solving the application of new energy such as wind power and the like in an oil field power supply system. The voltage drop control method in the prior art mainly focuses on aspects of increasing a reactive compensator, improving the capacity of a power grid and the like, and does not fully utilize the existing equipment, so that the final control effect is unsatisfactory, and the control cost is high.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a voltage drop control method containing new energy grid connection, which can realize reliable power supply in an oil field power supply system, improve the capacity of coping with power grid voltage fluctuation in the power supply process of an oil pumping well and further improve the reliability of the system.
In order to solve the technical problems, the invention provides the following technical scheme:
the invention provides a voltage drop control method containing new energy grid connection, which comprises the following steps:
s1: initializing system variables, and acquiring power grid voltage and power grid current data;
s2: judging whether the voltage drops according to the voltage and current changes of the power grid, if so, executing S3; otherwise, the control system works in a multi-energy complementary mode: i, storing energy by the energy storage inverter according to peak-valley electricity prices; ii, tracking and controlling the maximum power point of the wind turbine; iii, the load power grid of the pumping well is powered by the energy storage system and the power grid in a time-sharing manner according to the peak-valley electricity price;
s3: after determining the voltage drop, the control system works in the following voltage drop mode: i, switching a frequency converter of a motor of the oil pumping well to a voltage drop mode, namely energy storage and power supply; ii, the wind turbine generator is switched to a voltage drop control mode, namely reactive support, and the compensation reactive power is Q1; iii the energy storage system is switched to a voltage control mode-reactive support and active support; the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter;
s4: and when the voltage of the power grid is recovered, realizing the parameter switching of the controller: i, resetting parameters of an improved PIR power/current controller of the wind power converter; ii, resetting the PIR parameter of the voltage/current controller of the energy storage converter;
s5: after the parameter switching of the controller is completed, the control system works in a multi-energy complementary mode: i, storing energy by the energy storage inverter according to peak-valley electricity prices; ii, tracking and controlling the maximum power point of the wind turbine; iii, the load power grid of the pumping well is powered by the energy storage system and the power grid in a time-sharing manner according to the peak-valley electricity price;
during the voltage drop period, the energy storage converter continuously provides stable electric energy to ensure the normal operation of the motor load of the pumping unit; during the voltage recovery period, the energy storage converter can flexibly adjust the active current besides compensating the reactive power due to the addition of the energy storage battery pack.
Further, in the grid-connected side control of the wind power converter, the reactive support during the voltage drop of the power grid is realized by adopting the directional vector control of the voltage of the power grid and the support of the reactive Q1.
Further, in the control of the energy storage converter of the grid voltage drop, the double closed-loop grid voltage directional vector control is adopted, and reactive support during the grid voltage drop is realized through the support of the reactive Q2.
Further, the wind power converter adopts a proportional integral resonance controller PIR, and judges that the wind turbine generator is switched to a voltage drop control mode-reactive support Q1 according to a current vector extreme value.
Further, after the voltage of the power grid drops, the energy storage system is switched to a voltage control mode, namely reactive support and active support, and the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter.
Further, the voltage state is judged according to the real-time conditions of the voltage and the current, and the three-phase voltage after the power grid fault is as follows:
in formula (II) U'A、U'BAnd U'CThree-phase network phase voltages after a fault, respectively; u'mIs the grid voltage amplitude after the fault;
determining the voltage drop amplitude according to the effective voltage value, and calculating the unbalance degree:
in formula (II) U'AB、U'BCAnd U'CAThe three-phase grid line voltages after the fault are respectively;
the condition of overcurrent of converter equipment is directly caused after the voltage of a power grid drops, so that a current condition is added as a second condition for confirming the judgment of the voltage state, and the instantaneous current overcurrent is generated at a higher speed according to the hardware overcurrent I of the convertermaxSetting: max [ i'A,i'B,i'C]≥ImaxIn the formula (II), i'A、i'B、i'CRespectively, the current transients.
Further, the improved PIR controller is a PIR controller determined by the following expression:
in the formula, kpIs the proportionality coefficient, kiIs the integral coefficient, TiIs the integration time constant, krIs the resonant gain, kprIs the resonant gain adjustment coefficient, ωcThe resonant controller cuts off the frequency.
Further, reactive powers Q1 and Q2 are given by the PIR tuner as follows:
in the formula (I), the compound is shown in the specification,
and
active current and reactive current under a synchronous rotation dq coordinate system corresponding to the wind power converter;
and
active current and reactive current under a synchronous rotation dq coordinate system corresponding to the energy storage converter; i.e. iglimit1And iglimit2The limit currents are respectively a wind power converter and an energy storage converter.
According to the technical scheme, the voltage drop control method containing the new energy grid connection provided by the invention comprises the steps of firstly collecting power grid voltage and power grid current data; and then judging whether the voltage drops according to the voltage and current changes of the power grid, if so, controlling the system to work in the following voltage drop mode: i, switching a frequency converter of a motor of the oil pumping well to a voltage drop mode, namely energy storage and power supply; ii, the wind turbine generator is switched to a voltage drop control mode, namely reactive support, and the compensation reactive power is Q1; iii the energy storage system is switched to a voltage control mode-reactive support and active support; the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter; and when the voltage of the power grid is recovered, realizing the parameter switching of the controller: i, resetting parameters of an improved PIR power/current controller of the wind power converter; ii, resetting the PIR parameter of the voltage/current controller of the energy storage converter; after the parameter switching of the controller is completed, the control system works in a multi-energy complementary mode: i, storing energy by the energy storage inverter according to peak-valley electricity prices; ii, tracking and controlling the maximum power point of the wind turbine; iii, the load power grid of the pumping well is powered by the energy storage system and the power grid in a time-sharing manner according to the peak-valley electricity price; during the voltage drop period, the energy storage converter continuously provides stable electric energy to ensure the normal operation of the motor load of the pumping unit; during the voltage recovery period, the energy storage converter can flexibly adjust the active current besides compensating the reactive power due to the addition of the energy storage battery pack. Therefore, the control method provided by the invention meets the requirement of the power grid side on low voltage ride through of the wind turbine generator, and improves the capability of coping with power grid voltage fluctuation in the power supply process of the pumping well by means of an improved PIR controller, effective judgment of voltage state and the like, meets the requirement of reliable power supply of the motor load of the pumping well, and further improves the reliability of the system. By implementing the control method, the transition of the voltage drop process of the power grid can be realized. The control method provided by the invention can be popularized to other similar application occasions.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic diagram of power generation and load applied to a voltage sag control method including new energy grid connection according to an embodiment of the present invention;
fig. 2 is a flowchart of a voltage droop control method including new energy grid connection according to an embodiment of the present invention;
FIG. 3 is a control block diagram of a grid-connected side of a wind power converter with grid voltage dropping;
FIG. 4 is a block diagram of the energy storage converter control for grid voltage sag;
the meaning of the reference symbols in figure 1 above is explained as follows:
1 represents a pumping unit motor 1; 2 denotes a frequency converter 1; 3 represents an energy storage battery pack; 4 denotes an energy storage converter; 5 denotes a step-down transformer; 6 denotes a pumping unit motor 2; 7 denotes a frequency converter 2; 8 denotes a step-up transformer; 9 denotes a wind power generator 1; 10 denotes a wind power converter; 11 denotes an upper computer PLC controller; 12 denotes a step-down transformer; and 13 denotes an uninterruptible power supply.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Aiming at the defects in the prior art, the embodiment of the invention provides a voltage drop control method containing new energy grid connection, which is applied to occasions where new energy is applied to power generation in oil fields.
Before describing the control method provided by the present embodiment, a power generation and load scenario to which the control method provided by the present embodiment is applied will be described with reference to fig. 1. In fig. 1, 1 denotes a pumping unit motor 1; 2 denotes a frequency converter 1; 3 represents an energy storage battery pack; 4 denotes an energy storage converter; 5 denotes a step-down transformer; 6 denotes a pumping unit motor 2; 7 denotes a frequency converter 2; 8 denotes a step-up transformer; 9 denotes a wind power generator 1; 10 denotes a wind power converter; 11 denotes an upper computer PLC controller; 12 denotes a step-down transformer; and 13 denotes an uninterruptible power supply. As shown in fig. 1, 2 is used as a driver to drive a pumping unit motor 1; 7 as a driver drive 6; 1 and 7 are connected to a power supply bus 2; 4, a charge-discharge controller serving as a controller 3 is connected to the power supply bus 2; the power supply bus 2 is connected with the power supply bus 1 through 5; 9, wind-electricity energy conversion is realized through the control of 10, and finally the wind-electricity energy conversion is connected to the power supply bus 1 through the step-up transformer 8; the added 13 is used as an emergency power supply and is connected into a power supply bus 8 through a 12; all control devices realize cooperative control through 11.
Referring to fig. 2, the control method provided in this embodiment specifically includes the following steps:
step 101: initializing system variables, and collecting data of the voltage and current of the power grid.
This is done at 11 in fig. 1.
Step 102: judging whether the voltage drops according to the voltage of the power grid and the current change of the power grid, if so, executing a step 103; otherwise, step 106 is performed.
In the step, the voltage state is judged according to the change of the voltage and the current of the power grid; this is done independently from 4 and 10 in fig. 1.
Step 103: the control system operates in the following voltage drop mode: i, switching a frequency converter of a motor of the oil pumping well to a voltage drop mode, namely energy storage and power supply; ii, the wind turbine generator is switched to a voltage drop control mode, namely reactive support, and the compensation reactive power is Q1; iii the energy storage system is switched to a voltage control mode-reactive support and active support; and the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter.
Step 104: and judging whether the power grid voltage is recovered, if so, executing the step 105, otherwise, executing the step 103.
Step 105: realizing the parameter switching of the controller: i, resetting parameters of an improved PIR power/current controller of the wind power converter; ii the voltage/current controller PIR parameter of the energy storage converter is reset.
Step 106: the control system works in a multi-energy complementary mode: i, storing energy by the energy storage inverter according to peak-valley electricity prices; ii, tracking and controlling the maximum power point of the wind turbine; and iii, the load power grid of the pumping well is powered by the energy storage system and the power grid in a time-sharing manner according to the peak-valley electricity price.
In the embodiment, the wind power converter adopts a proportional integral resonant controller PIR, and judges that the wind turbine generator is switched to a voltage drop control mode-reactive support Q1 according to a current vector extreme value; after the voltage of the power grid drops, the energy storage system is switched to a voltage control mode, namely reactive support and active support, and the energy storage converter operates in a reactive compensation mode to compensate reactive power Q2 according to the voltage condition compensated by the wind power converter. And when the voltage of the power grid is recovered, realizing the parameter switching of the controller: i, resetting PIR parameters of a power/current controller of the wind power converter; ii the voltage/current controller PIR parameter of the energy storage converter is reset.
Therefore, during the voltage drop period, the energy storage converter can continuously provide stable electric energy to ensure the normal operation of the motor load of the pumping unit; during the voltage recovery period, due to the addition of the energy storage battery pack, the energy storage converter can flexibly adjust the active current in addition to the compensation of reactive power.
It can be understood that in the grid-connected side control of the wind power converter, the grid voltage directional vector control is adopted, and the reactive support during the grid voltage drop is realized through the support of the reactive Q1.
Fig. 3 shows a control block diagram of a wind power converter with grid voltage sag. Referring to fig. 3, in grid-connected side control of the wind power converter, grid voltage directional vector control is adopted, and reactive support during grid voltage drop is realized through support of reactive Q1; in the figure, the position of the upper end of the main shaft,
and ugqQ-axis voltage reference value and actual value respectively;
and ugdRespectively a d-axis voltage reference value and an actual value; l isgIs a grid-connected reactor reactance; omegagPower grid angular frequency decoupling compensation term
It can be understood that in the control of the energy storage converter of the grid voltage dip, the double closed-loop grid voltage directional vector control is adopted, and the reactive support during the grid voltage dip is realized through the support of the reactive Q2.
The control block diagram of the energy storage converter for the grid voltage sag is shown in fig. 4. Referring to fig. 4, in the control of the energy storage converter for the grid voltage sag, the double closed-loop grid voltage directional vector control is adopted, and reactive support during the grid voltage sag is realized through the support of the reactive Q2; in the figure, the position of the upper end of the main shaft,
and ugq2Q-axis voltage reference value and actual value respectively;
and ugd1Respectively a d-axis voltage reference value and an actual value; l isgIs a grid-connected reactor reactance; omegagPower grid angular frequency decoupling compensation term
Therefore, the control method provided by the embodiment can solve the technical problem of frequent shutdown caused by voltage drop in the power supply system of the oil field pumping well.
It can be understood that the wind power converter adopts a proportional integral resonant controller PIR, and judges that the wind turbine generator is switched to a voltage drop control mode-reactive support Q1 according to a current vector extreme value.
It can be understood that after the voltage of the power grid drops, the energy storage system is switched to a voltage control mode, namely reactive support and active support, and the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter.
It can be understood that the voltage state is judged according to the real-time conditions of the voltage and the current, and the three-phase voltage after the power grid fault is as follows:
in formula (II) U'A、U'BAnd U'CThree-phase network phase voltages after a fault, respectively; u'mIs the grid voltage amplitude after the fault;
determining the voltage drop amplitude according to the effective voltage value, and calculating the unbalance degree:
in formula (II) U'AB、U'BCAnd U'CAThe three-phase grid line voltages after the fault are respectively;
the condition of overcurrent of converter equipment is directly caused after the voltage of a power grid drops, so that a current condition is added as a second condition for confirming the judgment of the voltage state, and the instantaneous current overcurrent is generated at a higher speed according to the hardware overcurrent I of the convertermaxSetting: max [ i'A,i'B,i'C]≥ImaxIn the formula (II), i'A、i'B、i'CRespectively, the current transients.
It will be appreciated that the improved PIR controller is a PIR controller determined by the expression:
in the formula, kpIs the proportionality coefficient, kiIs the integral coefficient, TiIs the integration time constant, krIs the resonant gain, kprIs the resonant gain adjustment coefficient, ωcThe resonant controller cuts off the frequency. It can be seen that the improved PIR controller increases the resonant gain adjustment coefficient kprTherefore, the controller can improve the dynamic response speed according to the change of the proportionality coefficient, and can realize no static difference in a steady state by matching with an integral controller.
It will be appreciated that the reactive powers Q1 and Q2 are given by the PIR trimmers as follows:
in the formula (I), the compound is shown in the specification,
and
active current and reactive current under a synchronous rotation dq coordinate system corresponding to the wind power converter;
and
active current and reactive current under a synchronous rotation dq coordinate system corresponding to the energy storage converter; i.e. iglimit1And iglimit2The limit currents are respectively a wind power converter and an energy storage converter.
According to the technical scheme, the voltage drop control method with the new energy grid connection provided by the embodiment comprises the steps of firstly collecting power grid voltage and power grid current data; and then judging whether the voltage drops according to the voltage and current changes of the power grid, if so, controlling the system to work in the following voltage drop mode: i, switching a frequency converter of a motor of the oil pumping well to a voltage drop mode, namely energy storage and power supply; ii, the wind turbine generator is switched to a voltage drop control mode, namely reactive support, and the compensation reactive power is Q1; iii the energy storage system is switched to a voltage control mode-reactive support and active support; the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter; and when the voltage of the power grid is recovered, realizing the parameter switching of the controller: i, resetting parameters of an improved PIR power/current controller of the wind power converter; ii, resetting the PIR parameter of the voltage/current controller of the energy storage converter; after the parameter switching of the controller is completed, the control system works in a multi-energy complementary mode: i, storing energy by the energy storage inverter according to peak-valley electricity prices; ii, tracking and controlling the maximum power point of the wind turbine; iii, the load power grid of the pumping well is powered by the energy storage system and the power grid in a time-sharing manner according to the peak-valley electricity price; during the voltage drop period, the energy storage converter continuously provides stable electric energy to ensure the normal operation of the motor load of the pumping unit; during the voltage recovery period, the energy storage converter can flexibly adjust the active current besides compensating the reactive power due to the addition of the energy storage battery pack. Therefore, the control method provided by the embodiment meets the requirement of the power grid side on low voltage ride through of the wind turbine generator, and improves the capability of coping with power grid voltage fluctuation in the power supply process of the pumping well by means of an improved PIR controller, effective judgment of voltage states and the like, meets the requirement of reliable power supply of the motor load of the pumping well, and further improves the reliability of the system. By implementing the control method, the transition of the voltage drop process of the power grid can be realized. The control method provided by the embodiment can be popularized to other similar application occasions.
The above examples are only for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (7)
1. A voltage drop control method containing new energy grid connection is characterized by comprising the following steps:
s1: initializing system variables, and acquiring power grid voltage and power grid current data;
s2: judging whether the voltage drops according to the voltage and current changes of the power grid, if so, executing S3; otherwise, the control system works in a multi-energy complementary mode: i, storing energy by the energy storage converter according to peak-valley electricity prices; ii, tracking and controlling the maximum power point of the wind turbine; iii, the load power grid of the pumping well is powered by the energy storage system and the power grid in a time-sharing manner according to the peak-valley electricity price;
s3: after determining the voltage drop, the control system works in the following voltage drop mode: i, switching a frequency converter of a motor of the oil pumping well to a voltage drop mode, namely energy storage and power supply; ii, the wind turbine generator is switched to a voltage drop control mode, namely reactive support, and the compensation reactive power is Q1; iii the energy storage system is switched to a voltage control mode-reactive support and active support; the energy storage converter operates in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter;
s4: and when the voltage of the power grid is recovered, realizing the parameter switching of the controller: i, resetting parameters of an improved PIR controller of the wind power converter; ii, resetting the PIR parameter of the voltage/current controller of the energy storage converter;
s5: after the parameter switching of the controller is completed, the control system works in a multi-energy complementary mode: i, storing energy by the energy storage converter according to peak-valley electricity prices; ii, tracking and controlling the maximum power point of the wind turbine; iii, the load power grid of the pumping well is powered by the energy storage system and the power grid in a time-sharing manner according to the peak-valley electricity price;
during the voltage drop period, the energy storage converter continuously provides stable electric energy to ensure the normal operation of the motor load of the pumping unit; during the voltage recovery period, the energy storage converter can flexibly adjust active current besides compensating reactive power due to the addition of the energy storage battery pack;
wherein the improved PIR controller is a PIR controller determined by the following expression:
in the formula, kpIs the proportionality coefficient, kiIs the integral coefficient, TiIs the integration time constant, krIs the resonant gain, kprIs the resonant gain adjustment coefficient, ωcIs the resonant controller cutoff frequency.
2. The method as claimed in claim 1, characterized in that in grid-connected side control of the wind power converter, reactive support during grid voltage sag is achieved by support of reactive Q1 using grid voltage directional vector control.
3. Method according to claim 1, characterized in that in the control of the energy storage converter for grid voltage sag, a double closed-loop grid voltage directed vector control is used, with support by reactive Q2, to achieve reactive support during grid voltage sag.
4. The method according to claim 1, characterized in that the wind power converter adopts a proportional integral resonance controller PIR, and judges that the wind turbine generator is switched to a voltage sag control mode-reactive support Q1 according to a current vector extreme value.
5. The method according to claim 1, characterized in that after the grid voltage drops, the energy storage system is switched to a voltage control mode-reactive support and active support, and the energy storage converter is operated in a reactive compensation mode to compensate the reactive power Q2 according to the voltage condition compensated by the wind power converter.
6. The method according to claim 1, characterized in that the voltage state is judged according to the real-time conditions of voltage and current, and the three-phase voltage after the grid fault is:
in formula (II) U'A、U'BAnd U'CThree-phase network phase voltages after a fault, respectively; u'mIs the grid voltage amplitude after the fault;
determining the voltage drop amplitude according to the effective voltage value, and calculating the unbalance degree:
in formula (II) U'AB、U'BCAnd U'CAThe three-phase grid line voltages after the fault are respectively;
since a situation in which the converter device is over-current is directly caused after the grid voltage has dropped,therefore, the current condition is added, and as the second condition for confirming the voltage state judgment, the instantaneous current overcurrent generation speed is high, and the hardware overcurrent I is judged according to the convertermaxSetting: max [ i'A,i'B,i'C]≥ImaxIn the formula (II), i'A、i'B、i'CRespectively, the current transients.
7. Method according to claim 4 or 5, characterized in that the reactive powers Q1 and Q2 are given by a PIR tuner as follows:
in the formula igd1And igq1Active current and reactive current under a synchronous rotation dq coordinate system corresponding to the wind power converter; i.e. igd2And igq2Active current and reactive current under a synchronous rotation dq coordinate system corresponding to the energy storage converter; i.e. iglimit1And iglimit2The limit currents are respectively a wind power converter and an energy storage converter.
Priority Applications (1)
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