CN113036796A - Method and system for optimizing direct current restart control parameters - Google Patents

Method and system for optimizing direct current restart control parameters Download PDF

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Publication number
CN113036796A
CN113036796A CN202110262062.XA CN202110262062A CN113036796A CN 113036796 A CN113036796 A CN 113036796A CN 202110262062 A CN202110262062 A CN 202110262062A CN 113036796 A CN113036796 A CN 113036796A
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direct current
trigger angle
parameters
fan
initial
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CN113036796B (en
Inventor
段瑶
余浩
陈鸿琳
彭穗
宫大千
李惠玲
郑超
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Guangdong Power Grid Co Ltd
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Guangdong Power Grid Co Ltd
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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
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
    • H02H9/025—Current limitation using field effect transistors
    • 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
    • H02J3/381—Dispersed generators
    • 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
    • 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
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • 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
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • 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
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention discloses a method and a system for optimizing direct current restart control parameters, wherein the method comprises the steps of establishing a power grid steady-state and transient-state simulation model according to parameters and topological structures of power transmission and transformation elements; initializing and setting an initial value, a gear, an adjustment amplitude and a maximum value of the DC restart initial trigger angle; then carrying out direct current monopole twice restarting process simulation; when the fan enters low voltage ride through, increasing the gear of the initial trigger angle according to a preset value, and judging whether the value of the current initial trigger angle reaches the maximum value; if so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain an optimization result of the initial trigger angle; if not, returning to execute the DC monopole twice restarting process simulation step. The method can inhibit direct current impact generated in the restarting process during the period of non-clearing of the direct current line fault, reduce the descending amplitude of the bus voltage of the converter station, and relieve the threat of the fan to the system safety caused by entering low voltage ride through.

Description

Method and system for optimizing direct current restart control parameters
Technical Field
The invention relates to the technical field of power systems, in particular to a method and a system for optimizing direct current restart control parameters.
Background
At present, in order to realize the optimal configuration of energy resources, an extra-high voltage direct current transmission technology suitable for long-distance large-capacity transmission is widely applied in China. In practical application, when an alternating current power grid or a direct current system has fault disturbance, active power and reactive power exchanged between a converter station and the alternating current power grid of the extra-high voltage direct current transmission system which takes a converter composed of a semi-controlled thyristor as a core component fluctuate greatly, and therefore the grid-connected safety of new energy power generation bases such as wind power and photovoltaic in the vicinity of the converter station is threatened. And in an extra-high voltage direct current transmission system, the probability of the fault of the direct current line is higher. In view of this, a dc restart function that is similar to the function of an ac line reclosing and can effectively improve the operational reliability of a dc system is widely used.
However, in actual operation, a fault and a restart process of the dc system will cause a rapid and large change in dc active power, and therefore cause a significant fluctuation in converter station reactive power, so as to cause an impact on the ac power grid at the transmitting end and the receiving end. In a scene that new energy is large-scale grid-connected and extra-high voltage direct current feed-in coexist, direct current faults and reactive fluctuation of a converter station caused in a restarting process can cause a low voltage ride through chain reaction of a near-zone fan at a rectification side so as to threaten the operation safety of a power grid at a sending end. Therefore, how to provide an optimization method for dc restart control parameters to alleviate the low voltage ride through effect is one of the technical problems to be solved in the art.
Disclosure of Invention
The invention aims to provide a method and a system for optimizing direct current restart control parameters, which can inhibit direct current impact generated in a restart process during the period of non-clearing of direct current line faults, reduce the reduction amplitude of bus voltage of a converter station and relieve the threat of a fan to system safety caused by entering low voltage ride through by optimizing the size of a direct current restart initial trigger angle.
In order to overcome the defects in the prior art, the invention provides a method for optimizing direct current restart control parameters, which comprises the following steps:
establishing a power grid steady-state and transient-state simulation model according to the parameters and the topological structure of the power transmission and transformation element; the power transmission and transformation element is from a high-voltage direct-current power transmission system and a fan grid-connected system;
initializing and setting an initial value, a gear, an adjustment amplitude and a maximum value of the DC restart initial trigger angle;
performing direct current monopole twice restarting process simulation according to the initialization setting result;
when the fan enters low voltage ride through, increasing the gear of the initial trigger angle according to a preset value, and judging whether the value of the current initial trigger angle reaches the maximum value;
if so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle;
if not, returning to execute the step of simulating the direct current monopole twice restarting process.
Preferably, the method for optimizing the dc restart control parameter further includes: and when the fan does not enter low voltage ride through, directly adding the initial value to the product of the gear of the initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle.
Preferably, the parameters of the power transmission and transformation element include:
the system comprises a generator, excitation and speed regulation system data of the generator, alternating current transmission line parameters, transformer parameters, a network interconnection topological structure, a direct current transmission system control mode and controller parameters, fan low voltage ride through control protection parameters, regional generation power, load power and critical section exchange power operation data.
Preferably, the grid steady-state and transient-state simulation models comprise a grid load flow calculation model and a stability calculation model.
Preferably, the basis for determining whether the fan enters the low voltage ride through is as follows:
when the voltage of the fan outlet is lower than 0.9pu, the fan enters low voltage ride through;
when the voltage of the fan outlet is greater than or equal to 0.9pu, the fan does not enter low voltage ride through.
The invention also provides a direct current restart control parameter optimization system, which comprises:
the simulation model building unit is used for building a power grid steady-state and transient-state simulation model according to the parameters and the topological structure of the power transmission and transformation elements; the power transmission and transformation element is from a high-voltage direct-current power transmission system and a fan grid-connected system;
the initialization setting unit is used for carrying out initialization setting on an initial value, a gear, an adjustment amplitude value and a maximum value of the direct current restart initial trigger angle;
the simulation unit is used for simulating the direct current monopole twice restarting process according to the initialization setting result;
the first optimization unit is used for increasing the gear of the initial trigger angle according to a preset value when the fan enters low voltage ride through, and judging whether the value of the current initial trigger angle reaches the maximum value or not; if so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle; if not, returning to execute the step of simulating the direct current monopole twice restarting process.
Preferably, the dc restart control parameter optimization system further includes a second optimization unit, configured to directly add the initial value to a product of a gear of the initial firing angle and an adjustment amplitude when the fan does not enter a low voltage ride through, so as to obtain an optimization result of the initial firing angle.
Preferably, the parameters of the power transmission and transformation element include:
the system comprises a generator, excitation and speed regulation system data of the generator, alternating current transmission line parameters, transformer parameters, a network interconnection topological structure, a direct current transmission system control mode and controller parameters, fan low voltage ride through control protection parameters, regional generation power, load power and critical section exchange power operation data.
The present invention also provides a computer terminal device, comprising:
one or more processors;
a memory coupled to the processor for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement a method for DC restart control parameter optimization as in any above.
The present invention also provides a computer-readable storage medium having stored thereon a computer program for execution by a processor to implement the dc restart control parameter optimization method as defined in any of the above.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, by optimizing the size of the initial trigger angle of the direct current restart, the direct current impact generated in the restart process during the period of the direct current line fault which is not cleared can be inhibited, the reduction amplitude of the bus voltage of the converter station is reduced, and the threat to the safe operation of the system caused by the condition that the active power output is remarkably reduced because a fan in the vicinity of the converter station enters a low-voltage ride-through control process is effectively relieved.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic flowchart of a method for optimizing dc restart control parameters according to an embodiment of the present invention;
FIG. 2 is a schematic flow chart illustrating a method for optimizing DC restart control parameters according to another embodiment of the present invention;
FIG. 3 is a schematic diagram of an emulation simulation of a DC restart process according to yet another embodiment of the present invention;
FIG. 4 is a graph illustrating rectifier trigger lag angle response during a DC restart operation according to another embodiment of the present invention;
FIG. 5 is a graph of the AC bus voltage of the DC restart converter before and after parameter optimization according to yet another embodiment of the present invention;
FIG. 6 is a graph of the active power output of the DC restart fan before and after the parameter optimization according to yet another embodiment of the present invention;
fig. 7 is a schematic structural diagram of a dc restart control parameter optimization system according to an embodiment of the present invention.
Detailed Description
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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
It should be understood that the step numbers used herein are for convenience of description only and are not intended as limitations on the order in which the steps are performed.
It is to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The terms "comprises" and "comprising" indicate the presence of the described features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The term "and/or" refers to and includes any and all possible combinations of one or more of the associated listed items.
Referring to fig. 1, in an embodiment of the present invention, a method for optimizing dc restart control parameters is provided, including:
s10, establishing a power grid steady-state and transient-state simulation model according to the parameters and the topological structure of the power transmission and transformation elements; the power transmission and transformation element is from a high-voltage direct-current power transmission system and a fan grid-connected system;
in this embodiment, static and dynamic parameters of power transmission and transformation elements in the high-voltage direct-current power transmission system and the fan grid-connected system are collected, wherein the static and dynamic parameters mainly include data of a generator and an excitation and speed regulation system thereof, parameters of an alternating-current power transmission line, parameters of a transformer, a network interconnection topological structure, control modes and controller parameters of a direct-current power transmission system, low-voltage ride-through control protection parameters of a fan, and regional generated power, load power and critical section exchange power operation data.
For ease of understanding, various parameters present in the present embodiment are explained:
the generator excitation system: the power supply for supplying excitation current to a synchronous generator and its accessories are generally referred to, and generally comprise two main parts, namely an excitation power unit and an excitation regulator.
A generator speed regulation system: the rotating speed of the generator and the output frequency of the generator are controlled by the speed regulator.
Parameters of the alternating-current transmission line: the method is important basic data of power flow calculation, stable calculation, transient calculation, relay protection and line fault location of the power system, and the data quality directly influences the safe operation of the power system. The parameters of the alternating-current transmission line mainly comprise: positive sequence impedance, positive sequence capacitance, zero sequence impedance, zero sequence capacitance, zero sequence mutual impedance among loops, zero sequence mutual capacitance among loops, an alternating-current ultrahigh voltage transmission line phase parameter matrix and the like.
Transformer parameters: including rated capacity, capacity ratio, rated voltage, voltage ratio. Rated current, etc.
Network interconnection topology: the topology map is formed by the distribution situation and the connection state of the power system equipment, and information such as the position where the equipment is located, the name type of the equipment, the type of the connection medium between the equipment and the like can be obtained from the map.
Controlling a direct-current power transmission system: the method is mainly applied to the field of high-voltage direct-current transmission control protection.
The controller parameters are as follows: the relevant parameters of a PID controller, or a PI controller, are common.
Low voltage ride through: the LVRT is short, namely the low voltage transition capability, and refers to the capability of a small power generation system to bear the low voltage of a power grid with a certain limit value within a certain time without running out.
The section of power transmission: under a certain ground state power flow, a transmission line in which the directions of active power flows exhibited in the power system are identical if the directions are identical and the distances between different electric bodies are basically similar is called a transmission section.
And (3) power flow calculation of the power system: it is a basic electrical calculation for studying the steady-state operation of an electric power system and its task is to determine the operation state of the whole system, such as the voltage (amplitude and phase angle) on each bus, the power distribution and power loss in the network, etc., according to given operating conditions and network structure
Further, in this embodiment, a power grid steady-state and transient-state simulation model is established in the power grid large system simulation software PSD-BPA according to the topological structure of the power transmission and transformation element and the static and dynamic parameters through the power grid load flow calculation model and the stability calculation model.
S20, carrying out initialization setting on the initial value, the gear, the adjustment amplitude and the maximum value of the direct current restart initial trigger angle;
in this embodiment, the dc restart initial firing angle is initialized, and the initial value of the dc restart initial firing angle is set to α0Setting the gear k of the initial DC restart trigger angle to 0, and adjusting the amplitude of the initial DC restart trigger angle to delta alpha0The maximum value of the initial trigger angle of the DC restart is alpha0max。
S30, simulating the direct current monopole twice restarting process according to the initialization setting result;
in this embodiment, the simulation process of the dc single-pole twice-restarting process is shown in fig. 3, and specifically includes the following steps:
a) at tfWhen the direct current line is in short circuit fault at the moment, the triggering lag angle alpha of the rectifier is increased to be larger than 90 DEG, and the restarting phase shift angle alpha isfAnd continues for Δ T1And time, the direct current voltage and the current are controlled to be reduced so as to carry out line deionization, and further, the short-circuit fault is cleared.
b) At tr1The time system is started again for the first time, and the trigger lag angle alpha of the rectifier is alphafDown-regulated to restart initial firing angle alpha0When the rectifier enters a constant power control mode, the direct current system is ready to be put into operation again; because of the setting of the simulation program, the short-circuit fault is not cleared at the moment, so that the restart cannot be successful, and the trigger lag angle alpha of the rectifier continues to delta T2After time by0Increased to alpha againfThe line is decarburized, and in order to increase the success probability of the second restart, the decarburized time delta T is3Is greater than Δ T1。
c) At tfcAt the moment, the direct current line fault is cleared, and the system controls the trigger lag angle alpha of the rectifier to be maintained at alphafAnd continues for Δ T3After time at tr2The second restart process is carried out at any moment, the DC start is successfully carried out, and the DC power passes through delta T4Climbing after time and recovering to the original power transmission power Pd。
S40, when the fan enters low voltage ride through, increasing the gear of the initial trigger angle according to a preset value, and judging whether the value of the current initial trigger angle reaches the maximum value;
in the step, manual gear shifting is mainly carried out when the fan enters low voltage ride through so as to realize parameter optimization, specifically, a gear k of a direct current restart initial trigger angle is increased, and the direct current restart initial trigger angle is increased by delta alpha0And step S30 is executed again until the fan does not enter the low voltage ride through;
furthermore, after each gear shifting is finished, whether the current initial trigger angle is adjusted to the maximum value alpha needs to be judged0maxAnd the judgment result further comprises:
s401, if so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle, namely, the parameter optimization value is alpha0+kΔα0(ii) a And the adverse effect of the DC restart disturbance on the bus voltage of the converter station is relieved by optimally adjusting the restart initial trigger angle gear.
And S402, if not, returning to the step S30 and executing the steps sequentially.
According to the embodiment of the invention, the size of the initial trigger angle of the direct current restart is optimized, so that direct current impact generated in the restart process during the period of the direct current line fault which is not cleared can be inhibited, the reduction amplitude of the bus voltage of the converter station is reduced, and the threat of the fan to the system safety caused by the fact that the fan enters low voltage ride through is relieved.
Referring to fig. 2, in one embodiment of the present invention, when the fan does not enter the low voltage ride through, the product of the gear of the initial trigger angle that is initially set and the adjustment amplitude is directly added to the initial value of the initial trigger angle without performing the gear increasing operation, and the result is used as the optimization result of the initial trigger angle.
In one embodiment of the present invention, the basis for determining whether the fan enters the low voltage ride through is as follows:
when the voltage of the fan outlet is lower than 0.9pu, the fan enters low voltage ride through;
when the voltage of the fan outlet is greater than or equal to 0.9pu, the fan does not enter low voltage ride through.
In this embodiment, it should be noted that, according to the transient voltage response at the wind turbine end after the simulation of the dc monopole twice restart process and in combination with the low voltage ride through control protection setting parameter of the wind turbine generator, it is evaluated whether the wind turbine generator enters the low voltage ride through control process, that is, when the wind turbine outlet voltage is lower than 0.9pu, the wind turbine may enter the low voltage ride through in the restart disturbance process to cause a substantial reduction in the active power output, otherwise, the wind turbine may not enter the low voltage ride through.
For convenience of understanding, in one embodiment of the present invention, the implementation steps of the dc restart control parameter optimization method provided by the present invention are described by taking an actual power grid as an example:
(1) collecting AC/DC power grid parameters, and establishing a power grid simulation calculation model:
the method is characterized in that a practical new energy grid-connected system for transmitting power of an extra-high voltage direct current system to a certain wind power base is taken as an example, static and dynamic parameters of power transmission and transformation elements in a high-voltage direct current transmission system and a fan grid-connected system are collected, wherein the static and dynamic parameters comprise data of a generator and an excitation and speed regulation system of the generator, parameters of an alternating current transmission line, parameters of a transformer, a network interconnection topological structure, a control mode and controller parameters of the direct current transmission system, low voltage ride-through control protection parameters of the fan, and regional power generation power, load power and key. And establishing a power grid steady-state load flow and electromechanical transient simulation calculation model.
(2) Setting a direct current restart initial trigger angle:
restarting the DC to the initial trigger angle initial value alpha0Setting the angle to be 15 degrees, setting the gear k of the initial trigger angle of the direct current restart to be 0, and adjusting the amplitude value delta alpha of the initial trigger angle of the direct current restart0Is set to 5 degrees, and the maximum value alpha of the initial triggering angle of the direct current restart0maxSet at 60.
(3) Simulating a direct-current monopole twice restarting process:
at tfWhen the direct current line is short-circuited at 0.1s, the fault process lasts for 0.6s, and alpha is increased to alpha after the fault occursfWhen the direct current voltage at the sending end is controlled to be reduced to zero at 164 degrees, the corresponding direct current is reduced to zero, and the system continues to perform the first 0.15sThe minor line is dissociated and at tr1The first restart is carried out at a time of 0.25s, the initial firing angle α0The direct current voltage is set to be 15 degrees, the direct current is instantly and greatly improved by acting on the direct current line with the short-circuit fault, and large power impact is generated; duration of DeltaT2After 0.15s, the system detects that the restart was unsuccessful, then adjusts α up to 164 ° and performs the fault line deionization again; by Delta T3After 0.55s, at tr2A second restart is performed at time t, due to line fault, 0.95sfWhen the time is 0.7s, the direct current system is cleared up, and the direct current system is started successfully; by Delta T4After 0.05s, the dc power quickly climbs and recovers to the pre-fault level. The transient response of the rectifier trigger lag angle in response to the dc fault and restart process described above is shown in fig. 4.
(4) Evaluating whether the fan is triggered to enter low voltage ride through or not in the process of direct current restart disturbance:
in the process of first restarting, the direct current rapidly increases and exceeds a steady-state value, so that the reactive demand of the rectifier is greatly increased, therefore, the rectifier station absorbs a large amount of reactive power from an alternating current power grid, the bus voltage of the converter station is obviously reduced, the voltage of the converter bus at the direct current rectifier side falls to 0.82pu, the voltage of the wind power plant fan outlet falls to 0.88pu, and the fan enters low voltage ride through, so that the active power rapidly falls and can be recovered to the initial power only through the climbing process of about 1 s.
(5) Optimized adjustment restart initial trigger angle gear
The initial DC restart trigger angle gear k is increased by one, the initial DC restart trigger angle is sequentially increased by 5 degrees, and the step (3) is executed again until the fan does not enter low voltage ride through or the initial trigger angle is adjusted to the maximum value, the optimization process is finished, the initial DC restart trigger angle parameter is optimized to be 60 degrees, and fan end voltage response curves before and after the initial DC restart trigger angle parameter is optimized are shown in fig. 5. Will be alpha0The value is optimally adjusted to 60 degrees, the voltage of a commutation bus at the rectifying side and the voltage of the outlet of the fan can be increased to be more than 0.9pu, and the fan cannot be triggered to enter a low-voltage ride-through control process. The graph of the active power output response of the wind turbine before and after the optimization of the initial triggering angle parameter of the direct current restart is shown in fig. 6.
In the embodiment, the optimized parameters are adopted, so that the active power of the fan is quickly restored to the initial power after the direct current restarting process is finished, and the impact threat of the fan chain reaction caused by the direct current restarting process to the system is effectively relieved.
Referring to fig. 7, in an embodiment of the present invention, a dc restart control parameter optimization system is further provided, including:
the simulation model building unit 01 is used for building a power grid steady-state and transient-state simulation model according to the parameters and the topological structure of the power transmission and transformation elements; the power transmission and transformation element is from a high-voltage direct-current power transmission system and a fan grid-connected system;
the initialization setting unit 02 is used for performing initialization setting on an initial value, a gear, an adjustment amplitude value and a maximum value of the direct current restart initial trigger angle;
the simulation unit 03 is used for simulating the direct-current monopole twice restarting process according to the initialization setting result; specifically, the simulation process of the dc monopole twice restarting process is shown in fig. 3, and includes the following steps:
a) at tfWhen the direct current line is in short circuit fault at the moment, the triggering lag angle alpha of the rectifier is increased to be larger than 90 DEG, and the restarting phase shift angle alpha isfAnd continues for Δ T1And time, the direct current voltage and the current are controlled to be reduced so as to carry out line deionization, and further, the short-circuit fault is cleared.
b) At tr1The time system is started again for the first time, and the trigger lag angle alpha of the rectifier is alphafDown-regulated to restart initial firing angle alpha0When the rectifier enters a constant power control mode, the direct current system is ready to be put into operation again; because of the setting of the simulation program, the short-circuit fault is not cleared at the moment, so that the restart cannot be successful, and the trigger lag angle alpha of the rectifier continues to delta T2After time by0Increased to alpha againfThe line is decarburized, and in order to increase the success probability of the second restart, the decarburized time delta T is3Is greater than Δ T1。
c) At tfcAt the moment, the direct current line fault is cleared, and the system controls the trigger lag angle alpha of the rectifier to be maintained at alphafAnd continues for Δ T3After time at tr2The second restart process is carried out at any moment, the DC start is successfully carried out, and the DC power passes through delta T4Climbing after time and recovering to the original power transmission power Pd。
The first optimization unit 04 is configured to increase the gear of the initial trigger angle according to a preset value when the fan enters a low voltage ride through, and determine whether the value of the current initial trigger angle reaches a maximum value; if so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle; if not, returning to execute the step of simulating the direct current monopole twice restarting process.
In this embodiment, the first optimization unit 04 is configured to execute step S40, specifically, perform manual gear shifting when the fan enters a low voltage ride through to achieve parameter optimization, and specifically, increase the dc restart initial trigger angle gear k, and increase the dc restart initial trigger angle by Δ α0And step S30 is executed again until the fan does not enter the low voltage ride through; furthermore, after each gear shifting is finished, whether the current initial trigger angle is adjusted to the maximum value alpha needs to be judged0maxIf so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle, namely, the parameter optimization value is alpha0+kΔα0(ii) a And the adverse effect of the DC restart disturbance on the bus voltage of the converter station is relieved by optimally adjusting the restart initial trigger angle gear. If not, the simulation unit 03 is called again to return to the step S30, and the steps are executed from S30.
According to the system provided by the embodiment of the invention, the size of the initial trigger angle of the direct current restart is optimized, so that direct current impact generated in the restart process during the period that the direct current line fault is not cleared can be inhibited, the reduction amplitude of the bus voltage of the converter station is reduced, and the threat of the fan to the system safety caused by the fact that the fan enters low voltage ride through is relieved.
In an embodiment of the present invention, the dc restart control parameter optimization system further includes a second optimization unit, configured to directly add the initial value to a product of a gear of the initial firing angle and an adjustment amplitude when the fan does not enter a low voltage ride through, so as to obtain an optimization result of the initial firing angle.
In an embodiment of the present invention, there is further provided a computer terminal device, including:
one or more processors;
a memory coupled to the processor for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the direct current restart control parameter optimization method as described above.
The processor is used for controlling the overall operation of the computer terminal equipment so as to complete all or part of the steps of the direct current restart control parameter optimization method. The memory is used to store various types of data to support the operation at the computer terminal device, which data may include, for example, instructions for any application or method operating on the computer terminal device, as well as application-related data. The Memory may be implemented by any type of volatile or non-volatile Memory device or combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic Memory, flash Memory, magnetic disk, or optical disk.
The computer terminal Device may be implemented by one or more Application Specific integrated circuits (AS 1C), a Digital Signal Processor (DSP), a Digital Signal Processing Device (DSPD), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is configured to perform the dc restart control parameter optimization method according to any of the embodiments described above, and achieve technical effects consistent with the above methods.
In an embodiment of the present invention, a computer-readable storage medium including program instructions is further provided, and the program instructions, when executed by a processor, implement the steps of the dc restart control parameter optimization method according to any one of the above embodiments. For example, the computer readable storage medium may be the above memory including program instructions, which are executable by a processor of a computer terminal device to perform the dc restart control parameter optimization method according to any of the above embodiments, and achieve the technical effects consistent with the above method.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims (10)

1. A method for optimizing direct current restart control parameters is characterized by comprising the following steps:
establishing a power grid steady-state and transient-state simulation model according to the parameters and the topological structure of the power transmission and transformation element; the power transmission and transformation element is from a high-voltage direct-current power transmission system and a fan grid-connected system;
initializing and setting an initial value, a gear, an adjustment amplitude and a maximum value of the DC restart initial trigger angle;
performing direct current monopole twice restarting process simulation according to the initialization setting result;
when the fan enters low voltage ride through, increasing the gear of the initial trigger angle according to a preset value, and judging whether the value of the current initial trigger angle reaches the maximum value;
if so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle;
if not, returning to execute the step of simulating the direct current monopole twice restarting process.
2. The method of optimizing direct current restart control parameters according to claim 1, further comprising:
and when the fan does not enter low voltage ride through, directly adding the initial value to the product of the gear of the initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle.
3. The method of optimizing dc restart control parameters according to any one of claims 1 or 2, wherein the parameters of the electric transmission and transformation elements include:
the system comprises a generator, excitation and speed regulation system data of the generator, alternating current transmission line parameters, transformer parameters, a network interconnection topological structure, a direct current transmission system control mode and controller parameters, fan low voltage ride through control protection parameters, regional generation power, load power and critical section exchange power operation data.
4. The method of optimizing direct current restart control parameters according to claim 1 or 2, wherein the grid steady-state and transient-state simulation models include a grid load flow calculation model and a stability calculation model.
5. The direct current restart control parameter optimization method according to any one of claims 1 or 2, wherein the criterion for determining whether the fan enters a low voltage ride through is:
when the voltage of the fan outlet is lower than 0.9pu, the fan enters low voltage ride through;
when the voltage of the fan outlet is greater than or equal to 0.9pu, the fan does not enter low voltage ride through.
6. A dc restart control parameter optimization system, comprising:
the simulation model building unit is used for building a power grid steady-state and transient-state simulation model according to the parameters and the topological structure of the power transmission and transformation elements; the power transmission and transformation element is from a high-voltage direct-current power transmission system and a fan grid-connected system;
the initialization setting unit is used for carrying out initialization setting on an initial value, a gear, an adjustment amplitude value and a maximum value of the direct current restart initial trigger angle;
the simulation unit is used for simulating the direct current monopole twice restarting process according to the initialization setting result;
the first optimization unit is used for increasing the gear of the initial trigger angle according to a preset value when the fan enters low voltage ride through, and judging whether the value of the current initial trigger angle reaches the maximum value or not; if so, adding the initial value to the product of the gear of the current initial trigger angle and the adjustment amplitude to obtain the optimization result of the initial trigger angle; if not, returning to execute the step of simulating the direct current monopole twice restarting process.
7. The dc restart control parameter optimization system of claim 6, further comprising:
and the second optimization unit is used for directly adding the initial value to the product of the gear of the initial trigger angle and the adjustment amplitude value when the fan does not enter low voltage ride through to obtain the optimization result of the initial trigger angle.
8. The dc restart control parameter optimization system of any of claims 6 or 7, wherein the parameters of the electric transmission and transformation elements comprise:
the system comprises a generator, excitation and speed regulation system data of the generator, alternating current transmission line parameters, transformer parameters, a network interconnection topological structure, a direct current transmission system control mode and controller parameters, fan low voltage ride through control protection parameters, regional generation power, load power and critical section exchange power operation data.
9. A computer terminal device, comprising:
one or more processors;
a memory coupled to the processor for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the direct current restart control parameter optimization method of any of claims 1 to 5.
10. A computer-readable storage medium, on which a computer program is stored, the computer program being executed by a processor to implement the dc restart control parameter optimization method according to any of claims 1 to 5.
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