CN110544953B - Method and system for checking steady-state voltage after extra-high voltage direct current fault - Google Patents

Method and system for checking steady-state voltage after extra-high voltage direct current fault Download PDF

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CN110544953B
CN110544953B CN201910743974.1A CN201910743974A CN110544953B CN 110544953 B CN110544953 B CN 110544953B CN 201910743974 A CN201910743974 A CN 201910743974A CN 110544953 B CN110544953 B CN 110544953B
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current
steady
converter station
state voltage
bus
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CN110544953A (en
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贺静波
邱威
王超
赵兵
孙华东
易俊
刘明松
张书瑀
吴晨曦
贾俊川
王歆
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State Grid Corp of China SGCC
China Electric Power Research Institute Co Ltd CEPRI
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State Grid Corp of China SGCC
China Electric Power Research Institute Co Ltd CEPRI
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16533—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
    • G01R19/16538—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
    • G01R19/16576—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing DC or AC voltage with one threshold
    • 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
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • 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
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • 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)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses a method and a system for checking steady-state voltage after an extra-high voltage direct current fault, which comprise the following steps: determining the minimum input amount of inductive reactive compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition, and performing reactive configuration of the alternating current-direct current hybrid system; under the current reactive power configuration mode, calculating the difference value of the steady-state voltage of the converter station bus after the fault and the maximum value of steady-state voltage fluctuation as the minimum value of the steady-state voltage of the converter station bus before the fault; comparing the converter station bus voltage under the current direct-current power level with the converter station bus steady-state voltage minimum value before the fault to obtain a check result; and when the check result indicates that the converter station bus voltage at the current direct current power level is equal to the minimum value of the steady state voltage of the converter station bus before the fault, taking the current direct current power as the maximum direct current transmission power under the constraint of the steady state voltage. The implementation method is simple and easy to implement, and can obviously improve the calculation efficiency.

Description

Method and system for checking steady-state voltage after extra-high voltage direct current fault
Technical Field
The invention relates to the field of safe and stable operation of an alternating-current and direct-current hybrid power grid, in particular to a method and a system for checking steady-state voltage after an extra-high voltage direct-current fault.
Background
In a large alternating current-direct current hybrid power grid, power impact caused by direct current faults becomes a key factor influencing the safe and stable operation of a power system. After a bipolar blocking fault occurs in the direct current and the matched power supply and the direct current filter are cut off, if an operation mode of under-compensation of the direct current system (the direct current absorbs reactive power from the alternating current system) is initially adopted, the situation that the steady-state voltage of the system is increased often occurs. With the large-scale development of extra-high voltage direct current. The overvoltage problem of the power grid becomes more and more prominent after the ultrahigh voltage direct current is locked, and the power transmission capacity of the ultrahigh voltage direct current is severely limited.
However, in the current simulation calculation of an actual power grid, a unified reactive power configuration principle of a direct current system, selection of an initial reactive power exchange mode of an alternating current and direct current system, a steady-state voltage fluctuation judgment standard and the like are not formed, and a steady-state voltage fluctuation related checking method after direct current disturbance of the alternating current and direct current hybrid power grid needs to be developed urgently.
Disclosure of Invention
The invention provides a method and a system for checking steady-state voltage after an extra-high voltage direct current fault, which are used for solving the problem of how to check the steady-state voltage of an alternating current-direct current hybrid power grid after direct current disturbance so as to determine the maximum direct current transmission power in the alternating current-direct current hybrid power grid.
In order to solve the above problem, according to an aspect of the present invention, there is provided a steady-state voltage checking method after an extra-high voltage dc fault, the method including:
determining the minimum input amount of inductive reactive compensation of the alternating current system by taking the maximum value of the bus steady-state voltage of the converter station as a constraint condition, and performing reactive configuration of the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive compensation of the alternating current system;
under the current reactive power configuration mode, calculating the difference value between the steady-state voltage of the converter station bus after the fault and the maximum value of the steady-state voltage fluctuation, and taking the difference value as the minimum value of the steady-state voltage of the converter station bus before the fault;
comparing the converter station bus voltage under the current set direct current power level with the converter station bus steady-state voltage minimum value before the fault to obtain a check result;
and when the check result indicates that the bus voltage of the converter station under the current direct-current power level is equal to the minimum value of the steady-state voltage of the bus of the converter station before the fault, taking the current direct-current power as the maximum direct-current transmission power under the constraint of the steady-state voltage.
Preferably, the determining the minimum input amount of the inductive reactive compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition to perform reactive configuration of the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive compensation of the alternating current system includes:
adjusting the input amount of inductive reactive power compensation of the alternating current system until the bus voltage of the converter station is lower than the maximum value of the steady-state voltage of the bus of the converter station, and taking the current input amount of the inductive reactive power compensation of the alternating current system as the minimum input amount of the inductive reactive power compensation of the alternating current system;
and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of inductive reactive power compensation of the alternating current system.
Preferably, wherein the method further comprises:
when the check result indicates that the converter station bus voltage at the current direct current power level is larger than the converter station bus steady-state voltage minimum value before the fault, increasing the current direct current power according to a preset adjustment strategy, and recalculating until the check result indicates that the converter station bus voltage at the current direct current power level is equal to the converter station bus steady-state voltage minimum value before the fault; and
and when the check result indicates that the bus voltage of the converter station at the current direct current power level is smaller than the minimum value of the steady state voltage of the bus of the converter station before the fault, reducing the current direct current power according to a preset adjustment strategy, and recalculating until the check result indicates that the bus voltage of the converter station at the current direct current power level is equal to the minimum value of the steady state voltage of the bus of the converter station before the fault.
According to another aspect of the present invention, there is provided a steady-state voltage checking system after an extra-high voltage dc fault, the system comprising:
the reactive power configuration unit is used for determining the minimum input amount of inductive reactive power compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition, and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive power compensation of the alternating current system;
the steady-state voltage minimum value determining unit is used for calculating the difference value between the steady-state voltage of the converter station bus after the fault and the steady-state voltage fluctuation maximum value under the current reactive power configuration mode, and taking the difference value as the steady-state voltage minimum value of the converter station bus before the fault;
the check result obtaining unit is used for comparing the converter station bus voltage under the current set direct current power level with the converter station bus steady-state voltage minimum value before the fault so as to obtain a check result;
and the maximum direct-current transmission power determining unit is used for taking the current direct-current power as the maximum direct-current transmission power under the constraint of the steady-state voltage when the checking result indicates that the bus voltage of the converter station under the current direct-current power level is equal to the minimum value of the steady-state voltage of the bus of the converter station before the fault.
Preferably, the reactive power configuration unit, which uses the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition, determines the minimum input amount of the inductive reactive power compensation of the ac system, so as to perform reactive power configuration of the ac-dc hybrid system according to the minimum input amount of the inductive reactive power compensation of the ac system, includes:
adjusting the input amount of inductive reactive power compensation of the alternating current system until the bus voltage of the converter station is lower than the maximum value of the steady-state voltage of the bus of the converter station, and taking the current input amount of the inductive reactive power compensation of the alternating current system as the minimum input amount of the inductive reactive power compensation of the alternating current system;
and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of inductive reactive power compensation of the alternating current system.
Preferably, wherein the system further comprises:
the direct current power adjusting unit is used for increasing the current direct current power according to a preset adjusting strategy when the checking result indicates that the converter station bus voltage under the current direct current power level is larger than the minimum value of the converter station bus steady-state voltage before the fault, and the current direct current power is input into the direct current power setting unit; and
and when the check result indicates that the converter station bus voltage under the current direct current power level is smaller than the converter station bus steady-state voltage minimum value before the fault, reducing the current direct current power according to a preset adjustment strategy, and entering a direct current power setting unit.
The invention provides a method and a system for checking steady-state voltage after an extra-high voltage direct current fault, which comprise the following steps: determining the minimum input amount of inductive reactive compensation of the alternating current system by taking the maximum value of the bus steady-state voltage of the converter station as a constraint condition, and performing reactive configuration of the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive compensation of the alternating current system; under the current reactive power configuration mode, calculating the difference value between the steady-state voltage of the converter station bus after the fault and the maximum value of the steady-state voltage fluctuation, and taking the difference value as the minimum value of the steady-state voltage of the converter station bus before the fault; comparing the converter station bus voltage under the current direct-current power level with the converter station bus steady-state voltage minimum value before the fault to obtain a check result; and when the check result indicates that the bus voltage of the converter station under the current direct-current power level is equal to the minimum value of the steady-state voltage of the bus of the converter station before the fault, taking the current direct-current power as the maximum direct-current transmission power under the constraint of the steady-state voltage. The realization method is simple and easy to implement, and the calculation efficiency can be obviously improved in the check of the direct-current steady-state voltage of the converter station of the alternating-current and direct-current hybrid power grid after the alternating-current and direct-current disturbance, so that the manpower and material resources are saved, and the obvious economic benefit is created; and the method is suitable for checking the steady-state voltage after various direct-current faults, such as direct-current bipolar locking, direct-current bipolar twice full-voltage restarting and the like.
Drawings
A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
FIG. 1 is a flow diagram of a steady state voltage check method 100 after an extra-high voltage DC fault according to an embodiment of the invention;
FIG. 2 is a flow diagram of steady state voltage check after a DC bipolar latch-up fault according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a TITANGTAI DC-sending end system according to an embodiment of the invention;
FIG. 4 is a schematic diagram of AC system voltage with low total rejection in the near zone without DC commissioning according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of AC system voltages with 1 set of low impedance in DC non-commissioning according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of AC system voltages with 2 sets of low impedance in the DC off-stream mode according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of the AC system initial voltage at 3600MW maximum DC transmission power, in accordance with an embodiment of the present invention; and
fig. 8 is a schematic structural diagram of a steady-state voltage checking system 800 after an extra-high voltage dc fault according to an embodiment of the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Fig. 1 is a flowchart of a steady-state voltage checking method 100 after an extra-high voltage dc fault according to an embodiment of the present invention. As shown in fig. 1, the steady-state voltage check method after the extra-high voltage dc fault provided by the embodiment of the invention is simple and easy to implement, and can obviously improve the calculation efficiency, save manpower and material resources, and create obvious economic benefits in the check of the dc steady-state voltage of the converter station of the ac/dc hybrid power grid after the ac/dc disturbance; and the method is suitable for checking the steady-state voltage after various direct-current faults, such as direct-current bipolar locking, direct-current bipolar twice full-voltage restarting and the like. The steady-state voltage checking method 100 after the extra-high voltage direct current fault provided by the embodiment of the invention starts from step 101, determines the minimum input amount of inductive reactive power compensation of an alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition in step 101, and performs reactive power configuration of an alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive power compensation of the alternating current system.
Preferably, the determining the minimum input amount of the inductive reactive compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition to perform reactive configuration of the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive compensation of the alternating current system includes:
adjusting the input amount of inductive reactive power compensation of the alternating current system until the bus voltage of the converter station is lower than the maximum value of the steady-state voltage of the bus of the converter station, and taking the current input amount of the inductive reactive power compensation of the alternating current system as the minimum input amount of the inductive reactive power compensation of the alternating current system;
and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of inductive reactive power compensation of the alternating current system.
Because the reactive exchange principle in the design of the direct current system is to absorb reactive power from the system as much as possible (the reactive power can be provided by a matched power supply and the like, the filter has high manufacturing cost and is good in economic view, so that Q is goodrefIn generalIs a non-negative number. At present, for different reactive power exchange modes, considering economic factors such as filter manufacturing cost and the like, the reactive power exchange between direct current and a system is generally determined as follows.
The reactive power configuration principle of the direct current system is as follows: if the direct current adopts an under-compensation mode, namely the direct current absorbs reactive power from the alternating current system, the reactive power between the direct current system and the alternating current system is switched as follows: qex＝Qref+Q0Namely, the range of a group of filters is increased on the basis of the original dead zone; if the direct current adopts an overcomplete mode, the reactive power exchange between the direct current system and the alternating current system is as follows: qex＝Qref-Q0Wherein Q isrefRepresenting the reactive exchange between the dc system and the system. The principle is to try not to compensate too much, especially when the dc power is large, to control within the range of a set of filters (in terms of economy).
In the embodiment of the invention, the input amount of the inductive reactive power compensation of the alternating current system is continuously adjusted according to the constraint condition of the maximum value Usmax of the steady-state voltage of the bus of the converter station in the existing design book until the bus voltage of the converter station is lower than the Usmax, and the current input amount of the inductive reactive power compensation of the alternating current system is used as the minimum input amount of the inductive reactive power compensation of the alternating current system to determine the reactive power configuration principle.
After the dc bipolar blocking, the steady state voltage of the converter station is determined entirely by the initial reactive configuration, with the dc filter and the associated power supply all switched off. And the only factor for limiting the steady-state voltage of the converter station bus is that the steady-state voltage of the converter station bus does not exceed the maximum voltage of the converter station bus specified in the direct-current complete design book, so that the minimum input amount of inductive reactive compensation of the alternating-current system can be determined by taking the maximum value of the voltage of the converter station bus as a constraint.
In step 102, under the current reactive power configuration mode, a difference value between the steady-state voltage of the converter station bus after the fault and the maximum value of the steady-state voltage fluctuation is calculated, and the difference value is used as the minimum value of the steady-state voltage of the converter station bus before the fault.
Taking the dc bipolar blocking as an example, the steady-state voltage fluctuation of the bus of the converter station after the dc bipolar blocking is equal to the dc blocking, and the steady-state voltage after the measures are taken is subtracted from the steady-state voltage before the fault, that is:
ΔU＝US-U0，
wherein U represents steady state voltage fluctuation, Us represents the converter station bus steady state voltage after the fault, and U represents the converter station bus steady state voltage after the fault0Representing the converter station bus steady state voltage before the fault.
By modifying the above formula, one can obtain: u shape0＝US- Δ U; when the delta U is the maximum value of the steady-state voltage fluctuation in the complete set of design books, the steady-state voltage U of the converter station bus before the fault0Taking the minimum value, namely:
U0min＝US-ΔUmax。
therefore, under the premise of unchanged Us, U can be judged0Whether or not to take the minimum value U0minTo determine whether the steady-state voltage fluctuation reaches the upper limit DeltaUmax。
In step 103, the converter station bus voltage at the current set direct current power level is compared with the converter station bus steady-state voltage minimum value before the fault, so as to obtain a check result.
In step 104, when the check result indicates that the converter station bus voltage at the current dc power level is equal to the minimum value of the converter station bus steady-state voltage before the fault, the current dc power is taken as the maximum dc transmission power under the constraint of the steady-state voltage.
Preferably, wherein the method further comprises:
when the check result indicates that the converter station bus voltage at the current direct current power level is larger than the converter station bus steady-state voltage minimum value before the fault, increasing the current direct current power according to a preset adjustment strategy, and recalculating until the check result indicates that the converter station bus voltage at the current direct current power level is equal to the converter station bus steady-state voltage minimum value before the fault; and
and when the check result indicates that the converter station bus voltage at the current direct current power level is smaller than the converter station bus steady-state voltage minimum value before the fault, reducing the current direct current power according to a preset adjustment strategy, and recalculating until the check result indicates that the converter station bus voltage at the current direct current power level is equal to the converter station bus steady-state voltage minimum value before the fault.
In the embodiment of the invention, after the minimum input amount of inductive reactive power of the alternating-current system is determined, the maximum direct-current transmission power is determined by taking the minimum value of the steady-state voltage of the converter station bus before the fault as a constraint, and the transient overvoltage is not considered.
Wherein, if the steady state voltage of the bus of the converter station under the given DC power level is higher than the minimum value U of the steady state voltage of the bus of the converter station before the fault0minIf yes, increasing the current direct current power, and going to step 103;
if the steady state voltage of the bus of the converter station at the given direct current power level is higher than the minimum value U of the steady state voltage of the bus of the converter station before the fault0minIf yes, reducing the current direct current power and turning to step 103;
if the steady state voltage of the bus of the converter station at the given direct current power level is higher than the minimum value U of the steady state voltage of the bus of the converter station before the fault0minAnd the current direct-current power is the maximum direct-current transmission power under the constraint of the required steady-state voltage.
The switching converter station filter and the specified matching power supply generator reactive output can regulate voltage, the lowest operation voltage is influenced, the improvement of the direct current power is facilitated, the transient overvoltage needs to be checked further, and the direct current transmission power finally takes the minimum value under the constraint of the transient overvoltage and the steady-state voltage.
Fig. 2 is a flow chart of steady-state voltage check after dc bipolar latch-up fault according to an embodiment of the present invention. As shown in fig. 2, in the embodiment of the present invention, the minimum input amount of inductive reactive power compensation of the ac system is determined according to the highest voltage (maximum value of steady-state voltage) of the bus of the converter station determined in the dc package design book; then, determining a reactive configuration principle of the alternating current-direct current hybrid system, and determining initial direct current power; then, the steady-state voltage of the current converter station bus at the moment and the determined minimum value U of the steady-state voltage of the current converter station bus before the fault0minRatio of performanceThe method comprises the following steps: if the steady-state voltage of the bus of the converter station at the moment is higher than the minimum value U of the steady-state voltage of the bus of the converter station before the fault0minIncreasing the current direct current power; if the steady state voltage of the converter station bus at the moment is higher than the minimum value U of the steady state voltage of the converter station bus before the fault0minIf yes, reducing the current direct current power; if the steady-state voltage of the bus of the converter station at the moment is higher than the minimum value U of the steady-state voltage of the bus of the converter station before the fault0minAnd determining that the current direct-current power is the maximum direct-current transmission power under the constraint of the steady-state voltage.
The following specifically exemplifies embodiments of the present invention
In the embodiment of the present invention, a method for checking a steady-state voltage fluctuation after a dc fault will be described by taking the schematic diagram of the vitta dc sending system shown in fig. 3 as an example.
Firstly, determining inductive reactive minimum input quantity of victory and tin-meng stations according to the highest voltage (maximum value of steady-state voltage) of the bus of the converter station determined in the direct-current complete design book, and calculating results show that the inductive reactive minimum input quantity of the victory and tin-meng stations is not less than-289 x 2 to-578 MVar (inductive). The specific calculation process is as follows:
(1) and considering that the low impedance in the near region completely exits a worse mode, the charging power surplus 2324MVar is obtained after the high impedance is balanced with the charging power. As shown in fig. 4, the maximum 500kV bus voltage is 576kV, which is greater than 550kV of the converter station bus voltage determined in the dc package design book, and the maximum 1136kV of the 1000kV bus voltage.
(2) 1 set of low impedance is added, and the charging power surplus is 2035 MVar. As shown in fig. 5, after verification, the bus voltage of the converter station near zone high impedance, low impedance (1 group) and the line charging power after balance is 555.6kV, which is reduced by 21kV compared with that before no low impedance is applied.
(3) A set of low impedance is further added, and the bus voltage after the high impedance, the low impedance (2 sets) and the charging power are balanced is shown in fig. 6. At the moment, the surplus of charging power is 1746MVar, the bus voltage of the converter station is 544.9kV, and the maximum bus voltage required by the complete set of design specifications is less than 550 kV. For this reason, the initial win and tin union two-station inductive reactive minimum input amount is determined to be-289 MVar 2-578 MVar.
Then, after the minimum input quantity of inductive reactive power of the winning station and the tin union station is determined, the maximum direct current transmission power (transient overvoltage is not considered temporarily) is determined by taking the steady state minimum voltage of the bus of the converter station as a constraint (510kV or 500kV), the reactive power output of the switching converter station filter and a specified generator can be regulated, the minimum operation voltage is influenced, and the improvement of the direct current power is facilitated (the transient overvoltage needs to be checked, and the direct current power is small). According to the constraint, when the bus voltage of the converter station is determined to be not lower than 500kV and the reactive power output of each generator of 7 matched sets is about 25MVar, the maximum running direct-current transmission power is 3600MW, and the overcompensation of the converter station is 130 MVar. At this time, the initial voltage data of the ac system at the maximum dc transmission power of 3600MW is shown in fig. 7.
Fig. 8 is a schematic structural diagram of a steady-state voltage checking system 800 after an extra-high voltage dc fault according to an embodiment of the present invention. As shown in fig. 8, a steady-state voltage checking system 800 after an extra-high voltage dc fault according to an embodiment of the present invention includes: reactive power configuration unit 801, steady-state voltage minimum value determination unit 802, check result acquisition unit 803, and maximum direct-current transmission power determination unit 804.
Preferably, the reactive power configuration unit 801 is configured to determine a minimum input amount of inductive reactive power compensation of the ac system by using a maximum value of a steady-state voltage of the bus of the converter station as a constraint condition, and perform reactive power configuration of the ac/dc hybrid system according to the minimum input amount of inductive reactive power compensation of the ac system.
Preferably, the reactive power configuration unit 801, taking a maximum value of a steady-state voltage of a bus of a converter station as a constraint condition, determining a minimum input amount of inductive reactive power compensation of an ac system, so as to perform reactive power configuration of an ac-dc hybrid system according to the minimum input amount of inductive reactive power compensation of the ac system, includes:
adjusting the input amount of inductive reactive power compensation of the alternating current system until the bus voltage of the converter station is lower than the maximum value of the steady-state voltage of the bus of the converter station, and taking the current input amount of the inductive reactive power compensation of the alternating current system as the minimum input amount of the inductive reactive power compensation of the alternating current system;
and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of inductive reactive power compensation of the alternating current system.
Preferably, the steady-state voltage minimum value determining unit 802 is configured to, in the current reactive power configuration mode, calculate a difference between the steady-state voltage of the converter station bus after the fault and the maximum steady-state voltage fluctuation value, and use the difference as the minimum steady-state voltage of the converter station bus before the fault.
Preferably, the check result obtaining unit 803 is configured to compare the converter station bus voltage at the currently set dc power level with the converter station bus steady-state voltage minimum value before the fault, so as to obtain a check result.
Preferably, the maximum dc transmission power determining unit 805 is configured to, when the check result indicates that the converter station bus voltage at the current dc power level is equal to the minimum steady-state voltage of the converter station bus before the fault, use the current dc power as the maximum dc transmission power under the steady-state voltage constraint.
Preferably, wherein the system further comprises: the direct current power adjusting unit is used for increasing the current direct current power according to a preset adjusting strategy when the checking result indicates that the converter station bus voltage under the current direct current power level is larger than the minimum value of the converter station bus steady-state voltage before the fault, and the current direct current power is input into the direct current power setting unit; and when the check result indicates that the converter station bus voltage under the current direct current power level is smaller than the converter station bus steady-state voltage minimum value before the fault, reducing the current direct current power according to a preset adjustment strategy, and entering a direct current power setting unit.
The steady-state voltage checking system 800 after the extra-high voltage dc fault according to the embodiment of the present invention corresponds to the steady-state voltage checking method 100 after the extra-high voltage dc fault according to another embodiment of the present invention, and details thereof are not repeated herein.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the 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 embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (6)

1. A steady-state voltage checking method after an extra-high voltage direct current fault is characterized by comprising the following steps:
determining the minimum input amount of inductive reactive compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition, and carrying out reactive power configuration on the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive compensation of the alternating current system;
under the current reactive power configuration mode, calculating the difference value between the steady-state voltage of the converter station bus after the fault and the maximum value of the steady-state voltage fluctuation, and taking the difference value as the minimum value of the steady-state voltage of the converter station bus before the fault;
comparing the converter station bus voltage under the current set direct current power level with the converter station bus steady-state voltage minimum value before the fault to obtain a check result;
and when the check result indicates that the converter station bus voltage at the current direct-current power level is equal to the minimum value of the steady-state voltage of the converter station bus before the fault, taking the current direct-current power as the maximum direct-current transmission power under the constraint of the steady-state voltage.
2. The method according to claim 1, wherein the determining the minimum input amount of the inductive reactive power compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition to perform the reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive power compensation of the alternating current system comprises:
adjusting the input amount of inductive reactive power compensation of the alternating current system until the bus voltage of the converter station is lower than the maximum value of the steady-state voltage of the bus of the converter station, and taking the current input amount of the inductive reactive power compensation of the alternating current system as the minimum input amount of the inductive reactive power compensation of the alternating current system;
and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of inductive reactive power compensation of the alternating current system.
3. The method of claim 1, further comprising:
when the check result indicates that the converter station bus voltage at the current direct current power level is larger than the converter station bus steady-state voltage minimum value before the fault, increasing the current direct current power according to a preset adjustment strategy, and recalculating until the check result indicates that the converter station bus voltage at the current direct current power level is equal to the converter station bus steady-state voltage minimum value before the fault; and
and when the check result indicates that the bus voltage of the converter station at the current direct current power level is smaller than the minimum value of the steady state voltage of the bus of the converter station before the fault, reducing the current direct current power according to a preset adjustment strategy, and recalculating until the check result indicates that the bus voltage of the converter station at the current direct current power level is equal to the minimum value of the steady state voltage of the bus of the converter station before the fault.
4. A steady state voltage check system after an extra-high voltage direct current fault is characterized by comprising:
the reactive power configuration unit is used for determining the minimum input amount of inductive reactive power compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition, and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of the inductive reactive power compensation of the alternating current system;
the steady-state voltage minimum value determining unit is used for calculating the difference value between the steady-state voltage of the converter station bus after the fault and the steady-state voltage fluctuation maximum value under the current reactive power configuration mode, and taking the difference value as the steady-state voltage minimum value of the converter station bus before the fault;
the check result obtaining unit is used for comparing the converter station bus voltage under the current set direct current power level with the converter station bus steady-state voltage minimum value before the fault so as to obtain a check result;
and the maximum direct-current transmission power determining unit is used for taking the current direct-current power as the maximum direct-current transmission power under the constraint of the steady-state voltage when the checking result indicates that the bus voltage of the converter station under the current direct-current power level is equal to the minimum value of the steady-state voltage of the bus of the converter station before the fault.
5. The system according to claim 4, wherein the reactive power configuration unit determines the minimum input amount of inductive reactive power compensation of the alternating current system by taking the maximum value of the steady-state voltage of the bus of the converter station as a constraint condition, so as to perform reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of inductive reactive power compensation of the alternating current system, and the reactive power configuration unit comprises:
adjusting the input amount of inductive reactive power compensation of the alternating current system until the bus voltage of the converter station is lower than the maximum value of the steady-state voltage of the bus of the converter station, and taking the current input amount of the inductive reactive power compensation of the alternating current system as the minimum input amount of the inductive reactive power compensation of the alternating current system;
and performing reactive power configuration of the alternating current-direct current hybrid system according to the minimum input amount of inductive reactive power compensation of the alternating current system.
6. The system of claim 4, further comprising:
the direct current power adjusting unit is used for increasing the current direct current power according to a preset adjusting strategy when the checking result indicates that the converter station bus voltage under the current direct current power level is larger than the minimum value of the converter station bus steady-state voltage before the fault, and the current direct current power is input into the direct current power setting unit; and
and when the check result indicates that the converter station bus voltage under the current direct current power level is smaller than the converter station bus steady-state voltage minimum value before the fault, reducing the current direct current power according to a preset adjustment strategy, and entering a direct current power setting unit.
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CN111162529B (en) * 2020-01-13 2022-12-09 国家电网有限公司 Method and device for calculating alternating current bus voltage operating range of series-parallel power grid
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