CN115133505A - Method and system for quickly inhibiting short-circuit current fed into alternating current system by flexible direct current converter valve - Google Patents
Method and system for quickly inhibiting short-circuit current fed into alternating current system by flexible direct current converter valve Download PDFInfo
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- CN115133505A CN115133505A CN202210744754.2A CN202210744754A CN115133505A CN 115133505 A CN115133505 A CN 115133505A CN 202210744754 A CN202210744754 A CN 202210744754A CN 115133505 A CN115133505 A CN 115133505A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
- H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/16—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass
- H02H3/162—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass for ac systems
- H02H3/165—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass for ac systems for three-phase systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
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Abstract
The invention relates to a method and a system for quickly inhibiting short-circuit current of a flexible direct current converter valve fed-in alternating current system, wherein the method comprises the following steps: determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the parameters of the controller; when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of preset controller parameters, and reducing the output reactive power instruction value of the converter valve to zero; and after the alternating current system fault is cleared, adjusting a reactive power instruction value, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to a steady-state operation value according to the preset feasible range of the controller parameter. According to the invention, after the alternating current system fails, the level of short-circuit current fed in by the flexible direct current converter valve can be quickly reduced, and further, the equipment stress of the alternating current breaker for breaking the short-circuit current is reduced.
Description
Technical Field
The invention relates to the technical field of current suppression, in particular to a method and a system for quickly suppressing short-circuit current of a soft direct current converter valve feed-in alternating current system.
Background
Flexible direct current transmission using a modular multilevel converter is a new generation of transmission technology and has been rapidly developed in the last decade. As the level of flexible dc technology and equipment manufacturing matures, the voltage and power levels of flexible dc engineering are gradually increasing. The MMC is formed by cascading a series of submodules, and an Insulated Gate Bipolar Transistor (IGBT) adopted by each submodule has the independent turn-off capability, so that the defects of dynamic voltage sharing and static voltage sharing of the IGBT of the traditional two-level converter are overcome, high-frequency electromagnetic interference is reduced, a low-order harmonic filter is omitted, the floor area of the converter station is reduced, active power and reactive power can be independently controlled, and voltage and reactive power support can be provided for a weak alternating current power grid. Just because MMC-HVDC has this kind of unique voltage support ability, have important technical advantage in cross regional connection alternating current synchronous power grid and asynchronous power grid and isolation alternating current big power grid trouble.
The control system of the flexible direct current converter valve is mainly divided into a pole control part and a valve control part, wherein the pole control part generally adopts a double closed loop control mode, namely an outer loop part and an inner loop part. In polar control, the outer ring d-axis channel generally controls direct voltage or active power, and the outer ring q-axis channel generally controls alternating voltage or reactive power. And d-axis and q-axis of the polar control outer ring respectively output reference values of d-axis and q-axis of the current inner ring. The inner ring receives the current reference value output by the outer ring, performs difference operation with the d-axis component and the q-axis component of the actual current, and then sends the difference value to the inner ring proportional-integral controller, and finally outputs reference voltage and sends the reference voltage to the valve control, so that the purpose of controlling direct current voltage, active power, alternating current voltage and reactive power is achieved by controlling the voltage on the alternating current side.
The flexible direct current converter valve has alternating current fault ride-through capability, active power and reactive power are maintained to be transmitted in the fault process, and then short-circuit current is injected into an alternating current system, so that the level of the system short-circuit current is possibly caused to exceed the breaking capability of an alternating current breaker. Therefore, considering the control method, how to quickly suppress the short-circuit current fed into the flexible direct converter valve becomes a technical problem which needs to be solved urgently at present.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method and a system for quickly suppressing a short-circuit current fed into an ac system by a flexible-direct converter valve, which can quickly reduce the level of the short-circuit current fed into the flexible-direct converter valve after an ac system fault occurs, thereby reducing the stress on the ac circuit breaker to break the short-circuit current.
In order to achieve the purpose, the invention adopts the following technical scheme: a method for quickly suppressing short-circuit current fed into an alternating current system by a flexible direct current converter valve comprises the following steps: determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the parameters of the controller; when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of preset controller parameters, and reducing the output reactive power instruction value of the converter valve to zero; and after the alternating current system fault is cleared, adjusting a reactive power instruction value, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to a steady-state operation value according to the preset feasible range of the controller parameter.
Further, the determining upper and lower limits of the proportional coefficient and the integral time constant of the inner ring controller in the control system comprises:
determining the upper limit of a proportional coefficient and an integral time constant of an inner ring controller according to the stability requirements of a flexible direct current converter valve and an alternating current system;
and determining the lower limits of the proportional coefficient and the integral time constant of the inner ring controller according to the short-circuit current level of an alternating current system accessed by the flexible direct current converter valve and the dynamic performance of the flexible direct current converter valve.
And further, detecting the fault of the alternating current system according to the voltage characteristic of the flexible direct current conversion bus.
Further, the ac system fault includes:
when the amplitude of the three-phase alternating current voltage is smaller than a first set value
Judging that the two-phase or three-phase metal grounding serious fault exists;
when the algebraic sum of the three-phase alternating voltages is larger than a third set value
Judging the single-phase metal grounding fault;
when the amplitude change rate of the three-phase alternating voltage is greater than a second set value
And judging the fault to be high-resistance or far-end grounding fault.
Further, the switching of the proportional coefficient and the integral time constant of the inner-loop controller according to the feasible range of the preset controller parameter comprises:
when the alternating current system stably runs, the proportional coefficient and the integral time constant of the inner ring controller adopt lower limit values;
and after the alternating current system is judged to be in fault, switching the proportional coefficient and the integral time constant of the inner ring controller to an upper limit value.
Further, the ac system fault clearing comprises:
when the amplitude of the three-phase alternating current voltage is larger than a first set value
Judging that the two-phase or three-phase metal grounding serious fault is cleared;
when the algebraic sum of three-phase AC voltages is less than the third set value
When the fault is detected, the single-phase metal grounding fault is cleared;
when the amplitude variation rate of the three-phase alternating current voltage is less than a second set value
And judging that the high-resistance or far-end ground fault is cleared.
Further, the adjusting the reactive power instruction value and recovering the voltage of the commutation bus includes:
when the fault disappears and the voltage of the alternating current bus is recovered slowly, the flexible direct current converter valve switches the reactive power instruction value into output reactive power to support the voltage of the alternating current system to rise;
when the fault disappears and the alternating current bus has overvoltage, the flexible direct current converter valve switches the reactive power instruction value into reactive power absorption to help the voltage of the alternating current system to recover stably.
A short-circuit current rapid suppression system for a flexible direct current converter valve feed-in alternating current system comprises: the parameter determination module is used for determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in the control system and determining the feasible range of the controller parameter; the fault parameter adjusting module is used for switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of the preset controller parameter when the alternating current system has a fault, and reducing the output reactive power instruction value of the converter valve to zero; and the fault clearing parameter adjusting module is used for adjusting the reactive power instruction value after the alternating current system fault is cleared, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to the steady-state operation value according to the feasible range of the preset controller parameter.
A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform any of the above methods.
A computing device, comprising: one or more processors, memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods described above.
Due to the adoption of the technical scheme, the invention has the following advantages:
1. the invention considers the short-circuit current level of the alternating current system, the response characteristic of the controller and the stability of the alternating current and direct current system, determines the feasible range of the inner ring control parameter, dynamically switches in the steady state and transient state periods, and realizes the rapid control of the reactive power on the premise of ensuring the stability of the system.
2. According to the invention, after the AC system fault occurs, the reactive control speed of the flexible direct converter valve is improved by switching the parameters of the inner ring controller, the reactive power exchanged between the converter valve and the system is reduced to zero before the AC breaker acts, the short-circuit current level of the system is effectively reduced, and the breaking current stress of the breaker is reduced.
3. After the fault is cleared, the reactive instruction value of the converter valve is quickly adjusted according to the type and the requirement of the system, and the voltage of the system is quickly recovered.
Drawings
Fig. 1 is a schematic diagram of a method for rapidly suppressing short-circuit current fed into an ac system by a flexible-direct converter valve in accordance with an embodiment of the present invention;
FIG. 2 is a diagram illustrating fast switching of controller parameters in accordance with the present invention;
fig. 3 is a schematic diagram of a method for judging a fault of an ac system in the embodiment of the present invention.
Detailed Description
In order to make the objects, 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 drawings of the embodiments of the present invention. It should be apparent that the described embodiments are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be derived by a person skilled in the art from the description of the embodiments of the invention given above, are within the scope of protection of the invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The invention provides a method and a system for quickly inhibiting a short-circuit current fed into an alternating current system by a flexible-direct converter valve. The invention comprises the following steps: determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the controller parameters; when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of preset controller parameters, and reducing the output reactive power instruction value of the converter valve to zero; and after the alternating current system fault is cleared, adjusting a reactive power instruction value, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to a steady-state operation value according to the preset feasible range of the controller parameter. According to the invention, after the alternating current system fails, the level of short-circuit current fed in by the flexible direct current converter valve can be quickly reduced, and further, the equipment stress of the alternating current breaker for breaking the short-circuit current is reduced.
In an embodiment of the invention, a method for quickly suppressing a short-circuit current fed into an alternating current system by a flexible direct current converter valve is provided. In this embodiment, as shown in fig. 1, the method includes the following steps:
1) determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the controller parameters;
2) when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of preset controller parameters, and reducing the output reactive power instruction value of the converter valve to zero;
3) after the fault of the alternating current system is cleared, the reactive power instruction value is rapidly adjusted according to the system requirement, and support is provided for alternating current voltage recovery; and recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to the steady-state operation value according to the preset feasible range of the controller parameter.
In the step 1), determining the upper limit and the lower limit of the proportional coefficient and the integral time constant of the inner ring controller in the control system comprises the following steps:
1.1) determining the upper limit of a proportional coefficient and an integral time constant of an inner ring controller according to the stability requirements of a flexible direct converter valve and an alternating current system;
1.2) determining the lower limits of the proportional coefficient and the integral time constant of the inner ring controller according to the short-circuit current level of an alternating current system accessed by the flexible direct current converter valve and the dynamic performance of the flexible direct current converter valve, and further determining the feasible range of the inner ring parameters of the flexible direct current converter valve.
And in the step 2), detecting the fault of the alternating current system according to the voltage characteristic of the flexible direct current conversion bus.
Wherein, exchanging the system fault and including:
when the amplitude of the three-phase AC voltage
Is less than the first set value
Judging that the two-phase or three-phase metal grounding serious fault exists;
when the three-phase AC voltages are summed algebraically
Greater than a third set value
Judging the single-phase metal grounding fault;
rate of change of amplitude of three-phase AC voltage
Is greater than the second set value
And judging the fault as high-resistance or far-end ground fault.
In the step 2), the switching of the proportionality coefficient and the integral time constant of the inner-loop controller according to the preset feasible range of the controller parameter comprises the following steps:
2.1) when the alternating current system stably runs, the proportional coefficient and the integral time constant of the inner ring controller adopt lower limit values;
2.2) switching the proportional coefficient and the integral time constant of the inner ring controller to an upper limit value after judging that the alternating current system has a fault;
and 2.3) after the parameters of the inner ring controller are finished, switching the instruction value to zero through a selection switching module of the reactive instruction value.
In the step 3), whether the alternating current system fault is cleared is detected according to the voltage characteristics of the current conversion bus; according to the characteristic requirements of the alternating current system, the converter valve is quickly adjusted to output a reactive power instruction value, and the voltage recovery of the alternating current system is supported.
Wherein, exchanging the system fault clearance and including:
when amplitude of three-phase AC voltage
Greater than the first set value
Judging that the two-phase or three-phase metal grounding serious fault is cleared;
when the three-phase AC voltages are summed algebraically
Is less than the third set value
When the fault is detected, the single-phase metal grounding fault is cleared;
rate of change of amplitude of three-phase AC voltage
Is less than the second set value
And judging that the high-resistance or far-end ground fault is cleared.
In the step 3), adjusting the reactive power instruction value and recovering the voltage of the commutation bus includes the following steps:
3.1) when the fault disappears and the voltage of the alternating current bus is recovered slowly, the flexible-direct converter valve switches the reactive power instruction value into output reactive power to support the voltage of the alternating current system to rise;
3.2) when the fault disappears and the alternating current bus has overvoltage, the flexible direct current converter valve switches the reactive power instruction value into reactive power absorption to help the voltage of the alternating current system to recover stably.
The embodiment is as follows:
as shown in fig. 2, the method for quickly suppressing short-circuit current fed into an ac system by using a flexible dc converter valve of the present invention specifically includes the following steps:
1) determining the proportional coefficient of the inner ring controller according to the stability requirements of the flexible direct current converter valve and the alternating current systemK p And integral time constantT i And taking the value as the upper limit of the AC system fault transient periodParameters of the ring controller, i.e.K p2 AndT i2 ；
2) determining the lower limits of the proportional coefficient and the integral time constant of the inner ring controller according to the short-circuit current level of an alternating current system accessed by the flexible direct current converter valve and the dynamic performance of the flexible direct current converter valve, and taking the values as the parameters of the inner ring controller during the steady-state operation period of the flexible direct current converter valve, namely
And
；
in this embodiment, the inner loop controller parameters are employed during soft-straight steady state operation
And
the control selector selects branch 1 as control loop and outputs
And
then, respectively with
And
and the algebraic sum of the coupling terms is used as a modulation wave and sent to a converter valve control system.
3) As shown in fig. 3, the commutating bus voltage
Performing abc/α β transformation, specifically:
to obtain
Then, the RMS value is taken to obtain the AC voltage amplitude, and
comparing, when the value is lower than the above-mentioned value, judging that two-phase or three-phase metal grounding serious fault is existed, at the same time, making comparison with
And comparing, and judging as high-resistance or far-end ground fault when the value is larger than the value. After the three-phase voltage is taken out of the algebraic sum, the
And comparing, and judging as the single-phase metal earth fault when the value is larger than the value. Once any fault is determined, the ACFLT signal changes from 0 to 1.
4) Switching inner loop controller parameters toK p2 AndT i2 the control selector selects branch 2 as control loop and outputs△U td And△U tq then, respectively with△U td And△U tq and the algebraic sum of the coupling terms is used as a modulation wave and sent to a converter valve control system. Meanwhile, the reactive power instruction value is reduced to zero, the reactive power output by the flexible direct current converter valve is rapidly reduced, and the short-circuit current fed into the alternating current system is further reduced.
5) Voltage of current conversion busU t After the AC voltage is judged to disappear, the AC bus voltage is recoveredWhen the speed is slow, the flexible direct current converter valve switches the reactive power instruction value into output reactive power to support the voltage of the alternating current system to rise; when the fault disappears and the alternating current bus has overvoltage, the flexible direct current converter valve switches the reactive power instruction value into reactive power absorption to help the voltage of the alternating current system to recover stably.
Wherein, the failure determination method is the same as that in step 3), and is not described herein again.
6) After the voltage of the current conversion bus is recovered, the proportional coefficient and the integral time constant of the inner ring controller are switched back to the steady state operation valueK p1 AndT i1 。
in one embodiment of the present invention, a short-circuit current fast suppressing system for ac system fed by a flexible direct current converter valve is provided, which includes:
the parameter determination module is used for determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in the control system and determining the feasible range of the controller parameter;
the fault parameter adjusting module is used for switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of the preset controller parameter when the alternating current system has a fault, and reducing the output reactive power instruction value of the converter valve to zero;
and the fault clearing parameter adjusting module is used for adjusting the reactive power instruction value after the alternating current system fault is cleared, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to the steady-state operation value according to the preset feasible range of the controller parameter.
In the above embodiment, the determining, in the parameter determining module, the upper limit and the lower limit of the proportional coefficient and the integral time constant of the inner-loop controller in the control system includes:
the upper limit determining module is used for determining the upper limit of a proportional coefficient and an integral time constant of the inner ring controller according to the stability requirements of the flexible direct converter valve and the alternating current system;
and the lower limit determining module is used for determining the lower limit of the proportional coefficient and the integral time constant of the inner ring controller according to the short-circuit current level of the alternating current system accessed by the flexible direct current converter valve and the dynamic performance of the flexible direct current converter valve.
In the above embodiment, in the parameter adjusting module during fault, the fault of the ac system is detected according to the voltage characteristic of the flexible dc converter bus.
Wherein, exchange system fault includes:
a critical failure module, when the amplitude of the three-phase AC voltage is less than a first set value
Judging that the two-phase or three-phase metal grounding serious fault exists;
a single-phase metal earth fault module, when the sum of three-phase AC voltage is greater than a third set value
Judging the single-phase metal grounding fault;
a high resistance or far end ground fault module, when the amplitude change rate of the three-phase alternating current voltage is greater than a second set value
And judging the fault as high-resistance or far-end ground fault.
In the above embodiment, in the parameter adjusting module during the fault, the switching of the proportional coefficient and the integral time constant of the inner-loop controller according to the preset feasible range of the controller parameter includes:
when the alternating current system stably runs, the proportional coefficient and the integral time constant of the inner ring controller adopt lower limit values;
and after the alternating current system is judged to be in fault, switching the proportional coefficient and the integral time constant of the inner ring controller to an upper limit value.
In the above embodiment, in the fault clearing parameter adjusting module, the ac system fault clearing includes:
a serious fault clearing module for clearing the serious fault when the amplitude of the three-phase alternating current voltage is larger than a first set value
Judging that the two-phase or three-phase metal grounding serious fault is cleared;
single phase metal groundingA fault clearing module for clearing the fault when the sum of three-phase AC voltage algebra is less than a third set value
When the fault is detected, the single-phase metal grounding fault is cleared;
a high resistance or far end earth fault clearing module, when the amplitude change rate of the three-phase alternating current voltage is less than a second set value
And judging that the high-resistance or far-end ground fault is cleared.
In the above embodiment, in the fault clearing parameter adjusting module, adjusting the reactive power instruction value and recovering the voltage of the commutation bus includes:
when the fault disappears and the voltage of the alternating current bus is recovered slowly, the flexible direct current converter valve switches the reactive power instruction value into output reactive power to support the voltage of the alternating current system to rise;
when the fault disappears and the alternating current bus has overvoltage, the flexible direct current converter valve switches the reactive power instruction value into reactive power absorption to help the voltage of the alternating current system to recover stably.
The system provided in this embodiment is used for executing the above method embodiments, and for details of the process and the details, reference is made to the above embodiments, which are not described herein again.
In the computing device structure provided in an embodiment of the present invention, the computing device may be a terminal, and the computing device may include: a processor (processor), a communication Interface (Communications Interface), a memory (memory), a display screen, and an input device. The processor, the communication interface and the memory are communicated with each other through a communication bus. The processor is used to provide computing and control capabilities. The memory includes a non-volatile storage medium, an internal memory, the non-volatile storage medium storing an operating system and a computer program that when executed by the processor implements a throttling method; the internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The communication interface is used for carrying out wired or wireless communication with an external terminal, and the wireless communication can be realized through WIFI, a manager network, NFC (near field communication) or other technologies. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on a shell of the computing equipment, an external keyboard, a touch pad or a mouse and the like. The processor may call logic instructions in memory to perform the following method: determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the parameters of the controller; when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of preset controller parameters, and reducing the output reactive power instruction value of the converter valve to zero; and after the alternating current system fault is cleared, adjusting a reactive power instruction value, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to a steady-state operation value according to the preset feasible range of the controller parameter.
In addition, the logic instructions in the memory may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk, and various media capable of storing program codes.
Those skilled in the art will appreciate that the configurations of the above-described computing devices are merely some of the configurations associated with the present application and do not constitute limitations on the computing devices to which the present application may be applied, as a particular computing device may include more or fewer components, or some of the components may be combined, or have a different arrangement of components.
In one embodiment of the invention, a computer program product is provided, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions that, when executed by a computer, enable the computer to perform the methods provided by the above-described method embodiments, for example, comprising: determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the controller parameters; when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of preset controller parameters, and reducing the output reactive power instruction value of the converter valve to zero; and after the alternating current system fault is cleared, adjusting a reactive power instruction value, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to a steady-state operation value according to the preset feasible range of the controller parameter.
In one embodiment of the invention, a non-transitory computer-readable storage medium is provided, which stores server instructions that cause a computer to perform the methods provided by the above embodiments, for example, including: determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the controller parameters; when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of the preset controller parameter, and reducing the output reactive power instruction value of the converter valve to zero; and after the alternating current system fault is cleared, adjusting a reactive power instruction value, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to a steady-state operation value according to the preset feasible range of the controller parameter.
The implementation principle and technical effect of the computer-readable storage medium provided by the above embodiments are similar to those of the above method embodiments, and are not described herein again.
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 flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams 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.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; 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 (10)
1. A method for quickly suppressing short-circuit current fed into an alternating current system by a flexible direct current converter valve is characterized by comprising the following steps:
determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in a control system, and determining the feasible range of the controller parameters;
when the alternating current system fails, switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of preset controller parameters, and reducing the output reactive power instruction value of the converter valve to zero;
and after the alternating current system fault is cleared, adjusting a reactive power instruction value, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to a steady-state operation value according to the preset feasible range of the controller parameter.
2. The method for rapidly suppressing short-circuit current fed into an alternating current system by using a flexible direct current converter valve as claimed in claim 1, wherein the determining upper limits and lower limits of a proportional coefficient and an integral time constant of an inner loop controller in a control system comprises:
determining the upper limit of a proportional coefficient and an integral time constant of an inner ring controller according to the stability requirements of a flexible direct current converter valve and an alternating current system;
and determining the lower limits of the proportional coefficient and the integral time constant of the inner ring controller according to the short-circuit current level of an alternating current system accessed by the flexible direct current converter valve and the dynamic performance of the flexible direct current converter valve.
3. The method for rapidly suppressing short-circuit current fed into an alternating current system by using the flexible direct current converter valve as claimed in claim 1, wherein the alternating current system fault is detected according to the voltage characteristics of a flexible direct current converter bus.
4. The method for rapidly suppressing short-circuit current of a flexible direct current converter valve fed alternating current system according to claim 3, wherein the detecting the fault of the alternating current system according to the voltage characteristic of the flexible direct current converter bus comprises:
when three phases are crossedThe amplitude of the current voltage is less than the first set value
Judging that the two-phase or three-phase metal grounding serious fault exists;
when the algebraic sum of the three-phase alternating voltages is larger than a third set value
Judging the single-phase metal grounding fault;
when the amplitude variation rate of the three-phase alternating current voltage is greater than a second set value
And judging the fault as high-resistance or far-end ground fault.
5. The method for rapidly suppressing short-circuit current in an ac system fed by a flexible direct current converter valve according to claim 1, wherein the switching of the proportionality coefficient and the integral time constant of the inner loop controller according to the feasible range of the preset controller parameters comprises:
when the alternating current system stably runs, the proportional coefficient and the integral time constant of the inner ring controller adopt lower limit values;
and after the alternating current system is judged to be in fault, switching the proportional coefficient and the integral time constant of the inner ring controller to an upper limit value.
6. The method for rapidly suppressing short-circuit current in an AC system fed by a flexible direct current converter valve according to claim 1, wherein the fault clearing of the AC system comprises:
when the amplitude of the three-phase alternating current voltage is larger than a first set value
Judging that the two-phase or three-phase metal grounding serious fault is cleared;
when the algebraic sum of three-phase AC voltages is less than the third set value
When the single-phase metal grounding fault is cleared, judging that the single-phase metal grounding fault is cleared;
when the amplitude variation rate of the three-phase alternating current voltage is less than a second set value
And judging that the high-resistance or far-end ground fault is cleared.
7. The method for rapidly suppressing short-circuit current fed into an alternating current system by using a flexible direct current converter valve according to claim 1, wherein the adjusting the reactive power instruction value and the recovering of the voltage of a converter bus comprise:
when the fault disappears and the voltage of the alternating current bus is recovered slowly, the flexible direct current converter valve switches the reactive power instruction value into output reactive power to support the voltage of the alternating current system to rise;
when the fault disappears and the alternating current bus has overvoltage, the flexible direct current converter valve switches the reactive power instruction value into reactive power absorption to help the voltage of the alternating current system to recover stably.
8. A quick suppression system of gentle straight converter valve feed-in alternating current system short-circuit current, its characterized in that includes:
the parameter determination module is used for determining the upper limit and the lower limit of a proportional coefficient and an integral time constant of an inner ring controller in the control system and determining the feasible range of the controller parameter;
the fault parameter adjusting module is used for switching the proportional coefficient and the integral time constant of the inner ring controller according to the feasible range of the preset controller parameter when the alternating current system has a fault, and reducing the output reactive power instruction value of the converter valve to zero;
and the fault clearing parameter adjusting module is used for adjusting the reactive power instruction value after the alternating current system fault is cleared, recovering the voltage of the current conversion bus, and switching the proportional coefficient and the integral time constant of the inner ring controller back to the steady-state operation value according to the preset feasible range of the controller parameter.
9. A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-7.
10. A computing device, comprising: one or more processors, memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods of claims 1-7.
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