CN112152227A - Direct current blocking sending end power grid overvoltage phase calculation method and device considering phase modulator influence - Google Patents

Direct current blocking sending end power grid overvoltage phase calculation method and device considering phase modulator influence Download PDF

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CN112152227A
CN112152227A CN202010900843.2A CN202010900843A CN112152227A CN 112152227 A CN112152227 A CN 112152227A CN 202010900843 A CN202010900843 A CN 202010900843A CN 112152227 A CN112152227 A CN 112152227A
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direct current
fault
model
overvoltage
current system
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CN112152227B (en
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周友斌
肖繁
周鲲鹏
王涛
张侃君
李鹏
陈堃
黎恒炫
叶庞琪
杜镇安
王婷
文博
饶渝泽
张隆恩
陈永昕
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State Grid Corp of China SGCC
State Grid Hubei Electric Power Co Ltd
Electric Power Research Institute of State Grid Hubei Electric Power Co Ltd
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State Grid Corp of China SGCC
State Grid Hubei Electric Power Co Ltd
Electric Power Research Institute of State Grid Hubei Electric Power 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
    • H02J3/12—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
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1885—Arrangements for adjusting, eliminating or compensating reactive power in networks using rotating means, e.g. synchronous 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
    • H02J3/50—Controlling the sharing of the out-of-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
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • 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]
    • 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

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

Abstract

The invention provides a method and a device for calculating overvoltage stage of a direct current blocking sending end power grid considering the influence of a phase modulator, wherein the method comprises the following steps: step one, judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information, if so, executing a step two, and if so, executing a step three; determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device, and determining a front overvoltage calculation model and a rear overvoltage calculation model of the stabilizing device after direct current locking caused by the fault of a receiving end alternating current system; and step three, determining whether the stabilizing device is switched off or not according to the switching-off time of the stabilizing device, and determining a direct-current system fault to cause a direct-current locked front overvoltage calculation model and a switching-off rear overvoltage calculation model of the stabilizing device. The invention realizes the theoretical analysis of the sending end overvoltage under the working condition of direct current blocking and provides guidance for the optimization of the sending end power grid structure and the adjustment of the operation mode.

Description

Direct current blocking sending end power grid overvoltage phase calculation method and device considering phase modulator influence
Technical Field
The invention relates to the technical field of power systems, in particular to a method and a device for calculating overvoltage stages of a direct current blocking sending end power grid in consideration of the influence of a phase modulator.
Background
With continuous establishment and production of direct current engineering in China, the problem of 'strong and weak intersection' of power grid companies is increasingly highlighted, and higher requirements are put forward on dynamic reactive power support of power grids. Therefore, a national power grid company builds a batch of large phase modulators in the extra-high voltage converter station to improve the voltage stability level of the system. For a sending-end power grid, transient overvoltage of the sending-end alternating current power grid possibly caused by extra-high voltage high-capacity direct current locking can possibly cause large-scale network disconnection of sending-end wind turbine generators and the like in severe cases. The access of a new generation phase modulator can effectively inhibit the sending end overvoltage level, but the existing research on the influence of the phase modulator on the sending end overvoltage is lack of correlation analysis, particularly when a sending end safety control system tripping and direct current locking occur simultaneously, multiple overvoltage phenomena can be generated, and the research on the stable sending end overvoltage level of the phase modulator needs to be evaluated urgently to provide guidance for the subsequent configuration of a sending end power grid reactive power compensation device and the calculation of a system operation mode.
Disclosure of Invention
Aiming at the defects or the improvement requirements of the prior art, the invention provides a phase modulator influence-considered direct current blocking sending end power grid overvoltage phase calculation method, which considers the transient influence of the phase modulator per se and the strong excitation and low excitation effects on the one hand; on the other hand, the influence of the stable system tripping machine and the direct current blocking exit reactive power compensation device is considered. A specific calculation method is provided by analyzing the overvoltage levels of the alternating current power grid in different stages, and a basis is provided for overvoltage calculation and voltage stability analysis, and the result shows that the overvoltage level of the sending end can fully consider the influence of a phase modulator and can also consider the influence of a safety and stability system tripping and a reactive power compensation device quitting under a direct current locking condition on overvoltage.
In order to achieve the above object, according to an aspect of the present invention, there is provided a method and an apparatus for calculating an overvoltage phase of a dc blocking transmitting side power grid considering influence of a phase modulator, including the steps of:
step one, judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information, if so, executing a step two, and if so, executing a step three;
determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device, and determining a front overvoltage calculation model and a rear overvoltage calculation model of the stabilizing device after direct current locking caused by the fault of a receiving end alternating current system;
and step three, determining whether the stabilizing device is switched off or not according to the switching-off time of the stabilizing device, and determining a direct-current system fault to cause a direct-current locked front overvoltage calculation model and a switching-off rear overvoltage calculation model of the stabilizing device.
Further, in the step one, the dc control protection information is a time from when the dc control receives the fault information to when the dc control is locked.
Further, in the second step, the receiving end alternating current system fault causes a direct current locked-up post-switching-off overvoltage calculation model of the stabilizing device, and the receiving end alternating current system fault causes a direct current locked-up post-switching-off overvoltage calculation model is obtained through calculation according to a receiving end alternating current system fault phase modulator reactive power increment model, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a direct current bipolar locked-up post-conversion bus voltage rise and reactive power surplus correlation model;
the overvoltage calculation model after the switching-off of the stabilizing device after the direct current locking caused by the fault of the receiving end alternating current system is obtained through calculation according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a reactive power calculation model of the reducing of the alternating current system caused by the switching-off of the stabilizing device, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between the voltage rise and the reactive residual quantity of a converter bus after the direct current bipolar locking.
Further, in the third step, a calculation model of overvoltage of a bus at the front sending end of a generator tripping of the safety and stability device before direct current blocking caused by direct current system faults is obtained through calculation according to a reactive power increment model of a direct current system fault phase modulator, a sending end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive residual quantity of a converter bus after direct current bipolar blocking;
the method comprises the steps that a calculation model of overvoltage of a direct current system fault-caused direct current locked before tripping and after tripping of a stabilizing device is obtained through calculation according to a reactive power increment model of a direct current system fault phase modulator, a reactive power calculation model of an alternating current system reduction caused by tripping of the stabilizing device, a transmission end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive power surplus of a direct current bipolar locked converter bus.
Furthermore, the receiving end AC system fault phase modulator reactive power incremental model delta QTXJThe method is established by considering the sub-transient influence of the phase modulator and the strong excitation and low excitation functions according to a maximum reactive power model emitted by the phase modulator under the strong excitation condition:
Figure RE-GDA0002765837490000031
wherein QTXJcx_maxIs the maximum reactive power value, delta U, emitted by the phase modulator under the condition of forced excitationLFor bus voltage increments, XdIs a stator inductive reactance of a phase modulator;
Figure RE-GDA0002765837490000032
wherein U is the DC bus voltage, XdFor phase modifier stator inductive reactance, E0 is terminal potential under normal operating condition, SNRated capacity, k, for phase-modulatorsfmIs the strong excitation multiple of phase modulator, KCThe phase modulator short-circuit ratio.
Further, the reactive power incremental model of the direct current system fault phase modulator is established according to a reactive power model sent out by the phase modulator in an initial state:
Figure RE-GDA0002765837490000033
wherein QTXJ0Value of reactive power, AU, issued for initial state of phase-modifying machineLFor bus voltage increments, XdIs the stator inductive reactance of the phase modulator.
Further, the stabilizing device cuts off a reactive power calculation model delta Q causing reduction of an alternating current systemacComprises the following steps:
ΔQac＝PQJcotφjz (5)
wherein, PQJFor the value of the DC blocking cutter command, phi, received by the stabilizing devicejzThe power angle for the operation of the alternating current system unit is large;
the model delta Q for calculating the reactive power variation of the transmission end power grid without considering the converter valve is as follows:
ΔQ＝(ΔUL+1)2Bc+Qac+ΔQTXJ (6)
wherein, Delta ULThe bus voltage increment is adopted, and Bc is the equivalent admittance of the alternating current filter at the rectifying side and the reactive compensation capacitor; qacFor exchanging reactive power, Δ Q, between AC and DC systemsTXJThe reactive variable quantity is provided for the phase modulator;
voltage rise delta U of direct-current bipolar locked converter busLAnd the model of the correlation between the reactive residual quantity delta Q is as follows:
Figure RE-GDA0002765837490000041
wherein the content of the first and second substances,
Figure RE-GDA0002765837490000042
Xsis the equivalent impedance of the system, ULIs the bus voltage and SC is the converter station short circuit capacity.
A dc blocking transmit side power grid overvoltage phase calculation apparatus that accounts for phase modulator effects, comprising:
the fault type judging module is used for judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information;
the first overvoltage calculation model determining module is used for determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device when the fault type judging module judges that the power grid fault is the fault of the receiving-end alternating current system, and determining a front overvoltage calculation model of the stabilizing device after direct current locking and a rear overvoltage calculation model after the switching off caused by the fault of the receiving-end alternating current system;
and the second overvoltage calculation model determining module is used for determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device when the fault type judging module judges that the power grid fault is the fault of the receiving-end alternating current system, and determining a front overvoltage calculation model of the stabilizing device after direct current locking and a rear overvoltage calculation model after switching off caused by the fault of the receiving-end alternating current system.
Further, the overvoltage calculation model before the tripping of the stabilizing device after the direct current locking caused by the fault of the receiving end alternating current system is obtained by calculation according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between the voltage rise and the reactive residual quantity of a converter bus after the direct current bipolar locking;
the overvoltage calculation model after the switching-off of the stabilizing device after the direct current locking caused by the fault of the receiving end alternating current system is obtained through calculation according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a reactive power calculation model of the reducing of the alternating current system caused by the switching-off of the stabilizing device, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between the voltage rise and the reactive residual quantity of a converter bus after the direct current bipolar locking.
Further, a calculation model of overvoltage of a bus at the front transmitting end of the generator tripping of the safety and stability device before direct current blocking caused by direct current system faults is obtained through calculation according to a reactive power increment model of a direct current system fault phase modulator, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive residual quantity of a converter bus after direct current bipolar blocking;
the method comprises the steps that a calculation model of overvoltage of a direct current system fault-caused direct current locked before tripping and after tripping of a stabilizing device is obtained through calculation according to a reactive power increment model of a direct current system fault phase modulator, a reactive power calculation model of an alternating current system reduction caused by tripping of the stabilizing device, a transmission end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive power surplus of a direct current bipolar locked converter bus.
The embodiment of the invention provides a phase-modulator-influence-considered overvoltage phase calculation method for a direct-current blocking sending-end power grid, and aims to solve the problems that the current direct-current sending-end power grid overvoltage does not consider the influence of phase modulator access and the influence of a safety stabilizing device tripping, so that the calculated result has larger deviation from the actual result.
Drawings
Fig. 1 is a schematic diagram of a power grid structure of a phase modulator connected to a dc transmission terminal according to an embodiment of the present invention;
fig. 2 is a flowchart of a method for calculating an overvoltage phase of a dc blocking transmitting end power grid considering the influence of a phase modulator in the embodiment of the present invention.
Fig. 3 is a schematic diagram comparing an overvoltage simulation value and a calculated value of a dc transmitting end power grid under the condition that a stabilizing device does not switch off when the power grid fails in the embodiment of the invention, wherein a black curve is the simulation value, and a dotted line is the calculated value;
fig. 4 is a schematic diagram comparing a simulated value and a calculated value of the overvoltage of the dc transmitting end power grid under the tripping condition of the stabilizing device in the case of the power grid fault in the embodiment of the present invention, wherein a black curve is the simulated value, and a dotted line is the calculated value.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention relates to a phase modifier influence considered direct current blocking sending end power grid overvoltage phase calculation method, which comprises the following steps:
step one, judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information, if the receiving end alternating current system fault is detected, executing step two, and if the receiving end alternating current system fault is detected, executing step three; the dc control protection information may be a time from when the dc control receives the fault information to when the dc control locks, the dc locking time caused by the fault of the receiving-end ac system is s-level, and the dc locking time caused by the fault of the dc system is about 100 ms.
And step two, determining whether the stabilizing device is switched off or not according to the switching-off time of the stabilizing device, and determining a switching-off front overvoltage calculation model and a switching-off rear overvoltage calculation model of the stabilizing device after direct current locking caused by the fault of the receiving-end alternating current system.
The system comprises a receiving end alternating current system fault, a direct current locked-out post-stabilizer device generator tripping overvoltage calculation model, a receiving end alternating current system fault phase modulator reactive power increment model, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a direct current bipolar locked-out post-converter bus voltage rise and reactive power surplus correlation model, wherein the receiving end alternating current system fault causes the direct current locked-out post-stabilizer device generator tripping overvoltage calculation model to be obtained through calculation;
the overvoltage calculation model after the switching-off of the stabilizing device after the direct current locking caused by the fault of the receiving end alternating current system is obtained through calculation according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a reactive power calculation model of the reducing of the alternating current system caused by the switching-off of the stabilizing device, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between the voltage rise and the reactive residual quantity of a converter bus after the direct current bipolar locking.
And step three, determining whether the stabilizing device is switched off or not according to the switching-off time of the stabilizing device, and determining a direct-current system fault to cause a direct-current locked front overvoltage calculation model and a switching-off rear overvoltage calculation model of the stabilizing device.
The direct-current system fault causes a calculation model of overvoltage of a bus at the front sending end of a generator tripping of the safety and stability device before direct-current blocking, and the calculation model is obtained by calculation according to a reactive power increment model of a direct-current system fault phase modulator, a sending end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive residual quantity of a converter bus after direct-current bipolar blocking;
the method comprises the steps that a calculation model of overvoltage of a direct current system fault-caused direct current locked before tripping and after tripping of a stabilizing device is obtained through calculation according to a reactive power increment model of a direct current system fault phase modulator, a reactive power calculation model of an alternating current system reduction caused by tripping of the stabilizing device, a transmission end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive power surplus of a direct current bipolar locked converter bus.
Referring to fig. 1 and fig. 2, the second embodiment of the method for calculating the overvoltage phase of the dc blocking transmitting end power grid considering the influence of the phase modulator includes the following steps:
step (1) establishing the maximum reactive power value Q emitted under the condition of forced excitation of the phase modulatorTXJcx_maxAnd (4) modeling.
Figure RE-GDA0002765837490000071
Wherein U is the DC bus voltage, XdFor phase modifier stator inductive reactance, E0 is terminal potential under normal operating condition, SNRated capacity, k, for phase-modulatorsfmIs the strong excitation multiple of phase modulator, KCThe phase modulator short-circuit ratio.
Step (2) respectively establishing reactive power increment delta Q provided by a camera under the condition that the fault of a receiving end alternating current system and the fault of a direct current system cause overvoltage of voltage of a sending end bus according to the maximum reactive power model sent out under the condition of forced excitation of the phase modulator in the step (1) and the reactive power value sent out by the phase modulator in the initial stateTXJNamely a receiving end AC system fault phase modulator reactive power increment model and a DC system fault phase modulator reactive power increment model. The concrete description is as follows:
(a) under the condition of a fault of a receiving end alternating current system, the bus voltage of a transmitting end power grid is reduced, and then the bus voltage is increased after direct current locking. The phase modulator will then strongly excite to emit a maximum QTXJcx_maxAnd then enters a low excitation state. Thus, it is possible to provideReactive power increment delta Q provided by fault phase modulator of receiving end alternating current systemTXJThe reactive power incremental model of the fault phase modulator of the receiving end alternating current system comprises the following steps:
Figure RE-GDA0002765837490000081
(b) during the dc blocking process caused by the dc system fault, the voltage of the sending-side bus will rise after a short drop because the dc blocking will be caused very quickly by the dc fault. Thus, the reactive power delta Q provided by the fault phase modulator of the DC systemTXJThe reactive power incremental model of the direct current system fault phase modulator comprises the following steps:
Figure RE-GDA0002765837490000082
wherein QTXJ0Value of reactive power, AU, issued for initial state of phase-modifying machineLFor bus voltage increments, XdIs the stator inductive reactance of the phase modulator.
Step (3) establishing a reactive power calculation model delta Q of the steady device which causes the reduction of the alternating current system due to the trippingac。
ΔQac＝PQJcotφjz (5)
Wherein, PQJFor the value of the DC blocking cutter command, phi, received by the stabilizing devicejzThe power angle of the running of the alternating current system unit is large.
And (4) establishing a transmitting end power grid reactive power variation calculation model delta Q without considering the converter valve.
ΔQ＝(ΔUL+1)2Bc+Qac+ΔQTXJ (6)
Wherein, Delta ULThe bus voltage increment is adopted, and Bc is the equivalent admittance of the alternating current filter at the rectifying side and the reactive compensation capacitor; qacFor exchanging reactive power, Δ Q, between AC and DC systemsTXJThe reactive variable quantity is provided for the phase modulator.
Step (5) exchanging according to the converter stationDC network structure for building voltage rise delta U of DC bipolar locked converter busLAnd a correlation model between the reactive residual quantity Δ Q.
Figure RE-GDA0002765837490000083
Wherein the content of the first and second substances,
Figure RE-GDA0002765837490000084
Xsis the equivalent impedance of the system, ULIs the bus voltage and SC is the converter station short circuit capacity.
Step (6), judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information (for example, the time from the receiving of the fault information by the direct current control to the locking) and entering step (7) if the power grid fault is the receiving end alternating current system fault; if the direct current system fails, the method enters (10). The DC blocking time caused by the fault of the receiving end AC system is s-level, and the DC blocking time caused by the fault of the DC system is about 100 ms.
And (7) judging whether the stabilizing device is cut off, specifically, determining whether the stabilizing device is cut off after direct current locking according to the cutting time of the stabilizing device: judging whether the DC blocking time t is less than tawWherein t isawThe typical value for the shut down time of the safety device after receiving the dc blocking command is 160 ms. If t < tawIf yes, judging that the stabilizing device is not switched off, entering the step (8), and calculating the overvoltage level of the power grid at the sending end; if t > tawAnd (4) judging that the stabilizing device is switched off, and entering the step (9) to calculate the sending end overvoltage level.
And (8) calculating a model of overvoltage of a bus at the front sending end of the safety and stability device generator tripping after the fault of the alternating current system at the receiving end according to the reactive power increment model of the alternating current system at the receiving end in the step (2), the model of calculating the reactive power variation of the power grid at the sending end without considering the converter valve in the step (4) and the correlation model between the voltage rise and the reactive residual quantity of the converter bus after the direct current bipolar blocking in the step (5), namely calculating the overvoltage of the bus at the front sending end of the safety and stability device generator tripping after the fault of the alternating current system at the receiving end is caused according to the.
Figure RE-GDA0002765837490000091
Figure RE-GDA0002765837490000092
Wherein the content of the first and second substances,
Figure RE-GDA0002765837490000093
and (9) calculating a reactive power increment model of a receiving end alternating current system fault phase modulator according to the step (2), a reactive power calculation model of the alternating current system reduction caused by the switching of the stabilizing device in the step (3), a transmitting end power grid reactive power variation calculation model of the step (4) without considering a converter valve, and a correlation model between the voltage rise and the reactive residual quantity of the converter bus after the direct current bipolar locking in the step (5), namely calculating a calculation model of the overvoltage of the transmitting end bus after the switching of the stabilizing device caused by the direct current locking after the receiving end alternating current system fault according to the formula (3), the formula (5), the formula (6) and the formula (7).
Figure RE-GDA0002765837490000101
Figure RE-GDA0002765837490000102
Wherein the content of the first and second substances,
Figure RE-GDA0002765837490000103
Figure RE-GDA0002765837490000104
and (10) judging whether the stabilizing device is cut off, specifically, determining whether the stabilizing device is cut off after direct current locking according to the cutting time of the stabilizing device: judgment ofWhether the DC blocking time t is less than tawIf t < tawEntering the step (11), and calculating the overvoltage level of the power grid at the front sending end of the tripping machine of the stabilizing device; if t > tawAnd (5) entering the step (12) to calculate the overvoltage level of the sending end of the stabilizing device after the switching-off.
And (11) calculating a direct current system fault leading-end bus overvoltage of the safety and stability device generator tripping according to the direct current system fault phase modulator reactive power increment model in the step (2), the transmitting-end power grid reactive power variation calculation model in the step (4) without considering the converter valve and a correlation model between the voltage rise and the reactive residual quantity of the converter bus after direct current bipolar blocking in the step (5), namely calculating a direct current system fault leading-end bus overvoltage of the safety and stability device generator tripping according to the formula (4), the formula (6) and the formula (7).
Figure RE-GDA0002765837490000105
Figure RE-GDA0002765837490000106
Wherein the content of the first and second substances,
Figure RE-GDA0002765837490000107
Figure RE-GDA0002765837490000108
and (12) calculating a reactive power increment model of the direct current system fault phase modulator in the step (2), a reactive power calculation model of the alternating current system reduced by the switching machine of the stabilizing device in the step (3), a transmission end power grid reactive power variation calculation model of the step (4) without considering a converter valve, and a correlation model between the voltage rise and the reactive residual quantity of the direct current bipolar locked converter bus in the step (5), namely calculating a model of the overvoltage of the transmission end bus of the stabilizing device switched after the switching machine of the direct current locked by the direct current system fault according to the formula (4), the formula (5), the formula (6) and the formula (7).
Figure RE-GDA0002765837490000111
Figure RE-GDA0002765837490000112
Wherein the content of the first and second substances,
Figure RE-GDA0002765837490000113
Figure RE-GDA0002765837490000114
the embodiment of the invention also provides a direct current blocking sending end power grid overvoltage phase calculation device considering the influence of a phase modulator, which comprises a fault type judgment module, a first overvoltage calculation model determination module and a second overvoltage calculation model determination module;
the fault type judging module is used for judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information; the direct current control protection information can be the time from the time when the direct current control receives the fault information to the time of locking, the direct current locking time caused by the fault of the alternating current system at the receiving end is s level, and the direct current locking time caused by the fault of the direct current system is about 100 ms;
the first overvoltage calculation model determining module is used for determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device when the fault type judging module judges that the power grid fault is the fault of the receiving-end alternating current system, and determining a front overvoltage calculation model of the stabilizing device after direct current locking and a rear overvoltage calculation model after the switching off caused by the fault of the receiving-end alternating current system;
the system comprises a receiving end alternating current system fault, a direct current locked-out post-stabilizer device generator tripping overvoltage calculation model, a receiving end alternating current system fault phase modulator reactive power increment model, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a direct current bipolar locked-out post-converter bus voltage rise and reactive power surplus correlation model, wherein the receiving end alternating current system fault causes the direct current locked-out post-stabilizer device generator tripping overvoltage calculation model to be obtained through calculation;
the overvoltage calculation model after the switching-off of the stabilizing device after the direct current locking caused by the fault of the receiving end alternating current system is obtained through calculation according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a reactive power calculation model of the reducing of the alternating current system caused by the switching-off of the stabilizing device, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between the voltage rise and the reactive residual quantity of a converter bus after the direct current bipolar locking.
And the second overvoltage calculation model determining module is used for determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device when the fault type judging module judges that the power grid fault is the fault of the receiving-end alternating current system, and determining a front overvoltage calculation model of the stabilizing device after direct current locking and a rear overvoltage calculation model after switching off caused by the fault of the receiving-end alternating current system.
The direct-current system fault causes a calculation model of overvoltage of a bus at the front sending end of a generator tripping of the safety and stability device before direct-current blocking, and the calculation model is obtained by calculation according to a reactive power increment model of a direct-current system fault phase modulator, a sending end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive residual quantity of a converter bus after direct-current bipolar blocking;
the method comprises the steps that a calculation model of overvoltage of a direct current system fault-caused direct current locked before tripping and after tripping of a stabilizing device is obtained through calculation according to a reactive power increment model of a direct current system fault phase modulator, a reactive power calculation model of an alternating current system reduction caused by tripping of the stabilizing device, a transmission end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive power surplus of a direct current bipolar locked converter bus.
The embodiment of the invention provides a phase-modulator-influence-considered overvoltage phase calculation method for a direct-current blocking sending-end power grid, and aims to solve the problems that the current direct-current sending-end power grid overvoltage does not consider the influence of phase modulator access and the influence of a safety stabilizing device tripping, so that the calculated result has larger deviation from the actual result. Comparison of the simulated value and the calculated value in fig. 3 shows that the overvoltage calculation method provided by the embodiment of the invention is accurate in calculation, and the effectiveness of the direct-current transmission end power grid overvoltage calculation method under the condition that the stabilizing device does not shut down when the power grid fails is verified. The comparison of the simulated value and the calculated value of the value in fig. 4 shows that the overvoltage calculation method provided by the embodiment of the invention is accurate in calculation, and the effectiveness of the direct-current transmission end power grid overvoltage calculation method under the condition of the tripping of the stabilizing device during the power grid fault is verified.
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 (10)

1. A phase modulator influence considered direct current blocking sending end power grid overvoltage phase calculation method is characterized in that: the method comprises the following steps:
step one, judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information, if so, executing a step two, and if so, executing a step three;
determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device, and determining a front overvoltage calculation model and a rear overvoltage calculation model of the stabilizing device after direct current locking caused by the fault of a receiving end alternating current system;
and step three, determining whether the stabilizing device is switched off or not according to the switching-off time of the stabilizing device, and determining a direct-current system fault to cause a direct-current locked front overvoltage calculation model and a switching-off rear overvoltage calculation model of the stabilizing device.
2. The method of claim 1 for calculating an overvoltage phase of a dc blocking transmit side power grid in consideration of influence of a phase modulator, wherein: in the step one, the direct current control protection information is the locking time from the time when the direct current control receives the fault information.
3. The method of claim 1 for calculating an overvoltage phase of a dc blocking transmit side power grid in consideration of influence of a phase modulator, wherein: calculating a model for calculating overvoltage before tripping of the stabilizing device after direct current locking caused by the fault of the receiving end alternating current system according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a model for calculating reactive power variation of a transmitting end power grid without considering a converter valve and a correlation model between voltage rise and reactive residual quantity of a converter bus after direct current bipolar locking;
the overvoltage calculation model after the switching-off of the stabilizing device after the direct current locking caused by the fault of the receiving end alternating current system is obtained through calculation according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a reactive power calculation model of the reducing of the alternating current system caused by the switching-off of the stabilizing device, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between the voltage rise and the reactive residual quantity of a converter bus after the direct current bipolar locking.
4. The method of claim 1 for calculating an overvoltage phase of a dc blocking transmit side power grid in consideration of influence of a phase modulator, wherein: in the third step, a calculation model of overvoltage of a bus at the front transmitting end of the generator tripping of the safety and stability device before direct current blocking caused by direct current system faults is obtained through calculation according to a reactive power increment model of a direct current system fault phase modifier, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive residual quantity of a converter bus after direct current bipolar blocking;
the method comprises the steps that a calculation model of overvoltage of a direct current system fault-caused direct current locked before tripping and after tripping of a stabilizing device is obtained through calculation according to a reactive power increment model of a direct current system fault phase modulator, a reactive power calculation model of an alternating current system reduction caused by tripping of the stabilizing device, a transmission end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive power surplus of a direct current bipolar locked converter bus.
5. A method of calculating the over-voltage phase of a dc blocking transmit side power grid considering the influence of a phase modulator as claimed in claim 3, characterized in that: receiving end AC system fault phase modulator reactive power increment model delta QTXJThe method is established by considering the sub-transient influence of the phase modulator and the strong excitation and low excitation functions according to a maximum reactive power model emitted by the phase modulator under the strong excitation condition:
Figure FDA0002659728140000023
wherein QTXJcx_maxIs the maximum reactive power value, delta U, emitted by the phase modulator under the condition of forced excitationLFor bus voltage increments, XdIs a stator inductive reactance of a phase modulator;
Figure FDA0002659728140000021
wherein U is the DC bus voltage, XdFor phase modifier stator inductive reactance, E0 is terminal potential under normal operating condition, SNRated capacity, k, for phase-modulatorsfmIs the strong excitation multiple of phase modulator, KCThe phase modulator short-circuit ratio.
6. The method of claim 4 for calculating the over-voltage phase of a DC blocking transmit side power grid considering the influence of a phase modulator, wherein: the reactive power incremental model of the direct current system fault phase modulator is established according to a reactive power model sent out by the phase modulator in an initial state:
Figure FDA0002659728140000022
whereinQTXJ0Value of reactive power, AU, issued for initial state of phase-modifying machineLFor bus voltage increments, XdIs the stator inductive reactance of the phase modulator.
7. A method of calculating the overvoltage phase of a DC blocking transmit side power grid taking into account the effects of a phase modifier as claimed in claim 3 or 4, characterized by: reactive power calculation model delta Q for reducing alternating current system caused by switching off of stabilizing deviceacComprises the following steps:
ΔQac＝PQJcotφjz (5)
wherein, PQJFor the value of the DC blocking cutter command, phi, received by the stabilizing devicejzThe power angle for the operation of the alternating current system unit is large;
the model delta Q for calculating the reactive power variation of the transmission end power grid without considering the converter valve is as follows:
ΔQ＝(ΔUL+1)2Bc+Qac+ΔQTXJ (6)
wherein, Delta ULThe bus voltage increment is adopted, and Bc is the equivalent admittance of the alternating current filter at the rectifying side and the reactive compensation capacitor; qacFor exchanging reactive power, Δ Q, between AC and DC systemsTXJThe reactive variable quantity is provided for the phase modulator;
voltage rise delta U of direct-current bipolar locked converter busLAnd the model of the correlation between the reactive residual quantity delta Q is as follows:
Figure FDA0002659728140000031
wherein the content of the first and second substances,
Figure FDA0002659728140000032
Xsis the equivalent impedance of the system, ULIs the bus voltage and SC is the converter station short circuit capacity.
8. A direct current blocking sending end power grid overvoltage phase calculation device considering influence of a phase modulator is characterized in that: comprises that
The fault type judging module is used for judging whether the power grid fault is a receiving end alternating current system fault or a direct current system fault according to the direct current control protection information;
the first overvoltage calculation model determining module is used for determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device when the fault type judging module judges that the power grid fault is the fault of the receiving-end alternating current system, and determining a front overvoltage calculation model of the stabilizing device after direct current locking and a rear overvoltage calculation model after the switching off caused by the fault of the receiving-end alternating current system;
and the second overvoltage calculation model determining module is used for determining whether the stabilizing device is switched off or not according to the machine time of the stabilizing device when the fault type judging module judges that the power grid fault is the fault of the receiving-end alternating current system, and determining a front overvoltage calculation model of the stabilizing device after direct current locking and a rear overvoltage calculation model after switching off caused by the fault of the receiving-end alternating current system.
9. A dc blocking transmit side power grid overvoltage phase calculation apparatus considering influence of a phase modulator as claimed in claim 8, wherein:
the method comprises the steps that a receiving end alternating current system fault causes a direct current locked-up post-switching overvoltage calculation model of the stabilizing device, and the receiving end alternating current system fault causes a direct current locked-up post-switching overvoltage calculation model is obtained through calculation according to a receiving end alternating current system fault phase modulator reactive power increment model, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a direct current bipolar locked-up post-switching busbar voltage rise and reactive power surplus correlation model;
the overvoltage calculation model after the switching-off of the stabilizing device after the direct current locking caused by the fault of the receiving end alternating current system is obtained through calculation according to a reactive power increment model of a fault phase modulator of the receiving end alternating current system, a reactive power calculation model of the reducing of the alternating current system caused by the switching-off of the stabilizing device, a transmitting end power grid reactive power variation calculation model without considering a converter valve and a correlation model between the voltage rise and the reactive residual quantity of a converter bus after the direct current bipolar locking.
10. A dc blocking transmit side power grid overvoltage phase calculation apparatus considering influence of a phase modulator as claimed in claim 8, wherein:
the direct-current system fault causes a calculation model of overvoltage of a bus at the front sending end of a generator tripping of the safety and stability device before direct-current blocking, and the calculation model is obtained by calculation according to a reactive power increment model of a direct-current system fault phase modulator, a sending end power grid reactive power variation calculation model without considering a converter valve and a correlation model between voltage rise and reactive residual quantity of a converter bus after direct-current bipolar blocking;
the calculation model of the overvoltage of the bus at the sending end after the tripping of the stabilizing device before the direct current system fault causes the direct current locking is obtained by calculation according to a reactive power increment model of a direct current system fault phase modulator, a reactive power calculation model of the alternating current system caused by the tripping of the stabilizing device, a sending end power grid reactive power variation calculation model without considering the converter valve and a correlation model between the voltage rise and the reactive residual quantity of the converter bus after the direct current bipolar locking.
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