CN112653170A - Direct-current locking optimization cutting method for rigid weak cross-linking combined delivery system - Google Patents
Direct-current locking optimization cutting method for rigid weak cross-linking combined delivery system Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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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
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- 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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Abstract
The application discloses a method for optimizing a cutter of a rigid weak crosslinking outgoing system after direct current locking. Wherein, the method comprises the following steps: monitoring the running state of the direct current transmission system in real time, and determining the direct current power loss amount transmitted by the direct current transmission system before and after the direct current lockout fault according to the running state; determining the total amount of units which need to be cut off after the direct current blocking fault in order to keep the frequency of the alternating current system stable according to the loss amount of the direct current power and the maximum power unbalance amount which can be born by the power grid; determining a first priority of the alternating current transmission end power grid after the direct current blocking fault to cut off power of the thermal power generating unit; determining the power of the first priority cut thermal power generating unit to be a cut amount which ensures stable power angle and stable frequency under the condition that the power of the first priority cut thermal power generating unit is greater than or equal to the total amount of the thermal power generating units; and under the condition that the power of the thermal power generating unit is cut off in a first priority mode and is smaller than the total power of the thermal power generating unit, increasing the power cut amount to ensure that the frequency of the alternating current system is stable after the direct current blocking fault occurs.
Description
Technical Field
The application relates to the technical field of operation and control of power systems, in particular to a method for optimizing a cutting machine of a strong-direct-weak cross-linking combined delivery system after direct current locking.
Background
Energy resources and energy consumption in China are distributed in a reverse direction in geography, energy bases of thermal power, wind power and the like are mainly concentrated in western and northern regions except hydroelectric resources, the distance from load centers to east and middle load centers is far more than thousands of kilometers, and objective requirements of large-scale centralized development and large-capacity long-distance conveying exist. In recent years, with the rapid development of new energy power generation technology, the wind power and photovoltaic grid-connected capacity in China is continuously increased, and by combining the practical requirements of energy conservation and emission reduction in China and the practical requirements of large-scale power transmission of energy bases, the outward transmission of coal power, wind power and other types of power supplies in the west and north areas through an alternating current and direct current transmission line becomes common reality. At present, China has been put into operation one after another and continuously established multi-return-air-fire bundling extra-high voltage direct current transmission projects, the sending ends of the extra-high voltage direct current transmission projects are all typical weak sending end alternating current and direct current outgoing systems, a long chain type grid structure is connected into a main grid, new energy and thermal power are collected to achieve alternating current and direct current outgoing, and the characteristics of power supply support lack and weak sending ends are obvious.
After the direct current blocking fault, the output power is greatly reduced to be zero because the direct current channel is blocked, the direct current power is transferred through the alternating current outgoing channel, huge impact is caused to an alternating current system, the power angle swing of the units on two sides of the outgoing channel is caused, and if the initial outgoing power of the alternating current is high, the power angle instability of the units on two sides of the alternating current outgoing channel is caused. In order to ensure the stable power angle after the direct current blocking fault, a large number of generator sets at the sending end need to be cut off as soon as possible. On the other hand, due to the fact that the output power of the extra-high voltage direct current transmission system is large, after the extra-high voltage direct current transmission system is subjected to fault disturbance such as single-pole blocking and double-pole blocking, the frequency of a direct current sending end power grid is rapidly and greatly increased, and in order to guarantee the frequency of the sending end power grid after the direct current blocking fault is stable, sufficient safety control tripping measures are required.
The short-circuit capacity of the converter station after the safety control generator tripping is reduced, and the voltage of the bus of the direct current converter station and the bus of the near-area transformer substation of the alternating current outgoing channel is increased due to large-range retroversion of tide, so that the voltage may exceed the upper limit of the normal operation voltage of equipment, and the electrical equipment is damaged; in addition, if the frequency-stabilized cutting machine is not properly positioned, the power angle stability on both sides of the ac cross section will be deteriorated. Therefore, how to select the generator tripping position and sequence after the direct current blocking fault ensures the stability of the frequency of the power grid and simultaneously considers the transient stability of the system, can reduce the reduction degree of the short-circuit capacity of the converter station, and can reduce a series of secondary problems such as voltage instability, steady overvoltage and the like of a local area after large-range power float caused by generator tripping, and has great practical significance for the formulation of safety control generator tripping measures, the stable operation of an ultra-high voltage direct current transmission system and the power grid.
Aiming at the problems of converter station and near-zone voltage safety or local area voltage instability and the like caused by the fact that short-circuit capacity of the converter station is greatly reduced after a safety control switch-off machine after direct-current blocking fault exists in the prior art and the technical problem that power angle stability of two sides of an alternating-current section can be deteriorated due to improper frequency stability switch-off machine position, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the disclosure provides a method for optimizing a tripping operation of a strong-direct-weak cross-linking combined delivery system after direct-current blocking, and aims to solve the technical problems that the safety of a converter station and near-zone voltage or the voltage instability of a local area and the like caused by the large reduction of the short-circuit capacity of the converter station after the safety control tripping operation after the direct-current blocking fault exists in the prior art, and the stability of power angles at two sides of an alternating-current section can be deteriorated due to the improper position of a frequency-stable tripping operation.
According to an aspect of an embodiment of the present disclosure, there is provided a method for optimizing a cutting machine of a rigid weak cross-linking and delivering system after dc blocking, including: monitoring the running state of the direct current transmission system in real time, and determining the direct current power loss amount transmitted by the direct current transmission system before and after the direct current lockout fault according to the running state; determining the total amount of units which need to be cut off after the direct current blocking fault in order to keep the frequency of the alternating current system stable according to the loss amount of the direct current power and the maximum power unbalance amount which can be born by the power grid; determining first priority cut-off of thermal power generating unit power of an alternating current sending end power grid after the direct current blocking fault, wherein the first priority cut-off of the thermal power generating unit power is used for ensuring that the power angle of an alternating current system is stable after the direct current blocking fault, and the thermal power generating unit power of the alternating current sending end power grid after the direct current blocking fault is cut off for the first time; determining the power of the first priority cut thermal power generating unit to be a cut amount which ensures stable power angle and stable frequency under the condition that the power of the first priority cut thermal power generating unit is greater than or equal to the total amount of the thermal power generating units; and under the condition that the power of the thermal power generating unit is cut off in a first priority mode and is smaller than the total power of the thermal power generating unit, increasing the power cut amount to ensure that the frequency of the alternating current system is stable after the direct current blocking fault occurs.
According to another aspect of the embodiments of the present disclosure, there is also provided a system for optimizing a cutting machine of a rigid weak cross-linking and delivering system after dc blocking, including: the power loss determining module is used for monitoring the running state of the direct current transmission system in real time and determining the direct current power loss transmitted by the direct current transmission system before and after the direct current lockout fault according to the running state; the system comprises a unit total quantity determining module, a unit total quantity determining module and a unit total quantity determining module, wherein the unit total quantity determining module is used for determining the total quantity of the units which need to be cut off after the direct current blocking fault in order to keep the frequency of an alternating current system stable according to the direct current power loss quantity and the maximum power unbalance quantity which can be borne by a power grid; the method comprises the steps that a first thermal power generating unit power removing module is determined and used for determining first thermal power generating unit power of an alternating current sending end power grid after direct current blocking faults, and the first thermal power generating unit power removing module is used for ensuring that the power angle of an alternating current system is stable after the direct current blocking faults and the thermal power generating unit power of the alternating current sending end power grid after the direct current blocking faults is removed firstly; the system comprises a power cut quantity determining module, a power cut quantity determining module and a power cut quantity determining module, wherein the power cut quantity determining module is used for determining the power of the first priority cut thermal power generating unit to be the power cut quantity which ensures stable power angle and stable frequency under the condition that the power of the first priority cut thermal power generating unit is larger than or equal to the total power generating unit quantity; and the generator tripping quantity increasing module is used for increasing the generator tripping quantity to ensure the frequency stability of the alternating current system after the direct current blocking fault is ensured under the condition that the first priority is used for cutting off the power of the thermal power generating unit and is smaller than the total power of the thermal power generating unit.
In the invention, the cutting method is optimized after direct current locking through a strong weak cross-linking and outward conveying system. The method comprises the steps of firstly analyzing effectiveness of generator tripping positions for ensuring power angle stability and frequency stability after direct current blocking faults respectively, preferably providing generator tripping measures aiming at power angle instability after faults, further providing additional generator tripping measures aiming at frequency stability problems, and providing an optimization method for safety control generator tripping after direct current blocking faults from the viewpoint of avoiding secondary problems such as steady-state overvoltage and the like caused after generator tripping.
And the problems of safe converter station and near-region voltage or voltage instability of local regions and the like caused by the fact that short-circuit capacity of the converter station is greatly reduced after the safety control switching-off machine after the direct-current blocking fault exists in the prior art and the technical problem that the power angle stability of two sides of an alternating-current section is deteriorated due to the fact that the frequency stability switching-off machine is not properly positioned are solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure. In the drawings:
FIG. 1 is a schematic flow chart of a method for optimizing a cutting machine after DC blocking in a strong-direct-weak cross-linking combined delivery system according to an embodiment of the present disclosure;
FIG. 2 is a schematic flow diagram of an optimal cutting machine after DC blocking according to an embodiment of the present disclosure;
FIG. 3 is a schematic flow diagram of a strong, direct and weak cross-linking delivery system according to an embodiment of the present disclosure;
FIG. 4 is a schematic diagram of a power angle curve of area A relative to area B after a DC bipolar latch-up fault according to an embodiment of the disclosure;
FIG. 5 is a schematic diagram of a power angle curve of area A versus area B after 4300MW of a direct current bipolar latch-up failure, according to an embodiment of the present disclosure; and
fig. 6 is a schematic diagram of a system for optimizing a cutting machine after dc blocking for a strong direct and weak cross-linking and outward conveying system according to an embodiment of the disclosure.
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.
According to a first aspect of the embodiment, a method for optimizing a cutter of a strong weak cross-linking and outward conveying system after direct current blocking is provided. Fig. 1 shows a schematic flow diagram of the method, which, with reference to fig. 1, comprises:
s102: monitoring the running state of the direct current transmission system in real time, and determining the direct current power loss amount transmitted by the direct current transmission system before and after the direct current lockout fault according to the running state;
s104: determining the total amount of units which need to be cut off after the direct current blocking fault in order to keep the frequency of the alternating current system stable according to the loss amount of the direct current power and the maximum power unbalance amount which can be born by the power grid;
s106: determining first priority cut-off of thermal power generating unit power of an alternating current sending end power grid after the direct current blocking fault, wherein the first priority cut-off of the thermal power generating unit power is used for ensuring that the power angle of an alternating current system is stable after the direct current blocking fault, and the thermal power generating unit power of the alternating current sending end power grid after the direct current blocking fault is cut off for the first time;
s108: determining the power of the first priority cut thermal power generating unit to be a cut amount which ensures stable power angle and stable frequency under the condition that the power of the first priority cut thermal power generating unit is greater than or equal to the total amount of the thermal power generating units; and
s110: under the condition that the power of the thermal power generating unit is cut off in a first priority mode and is smaller than the total power of the thermal power generating unit, the power cut amount is increased to ensure that the frequency of the alternating current system is stable after the direct current blocking fault occurs.
Referring to fig. 2, in the present invention, the strong weak cross-linking and outward-sending system includes a dc power transmission system and an ac system, and the ac system includes an ac sending-end power grid and an ac receiving-end power grid. Monitoring the running state of the direct current transmission system in real time, respectively recording the active power transmitted by the direct current transmission system before and after the direct current blocking fault, and obtaining the direct current power loss P before and after the direct current blocking faultd. According to the loss P of DC powerdAnd the maximum power unbalance P that the power grid can bearΔDetermining the total amount P of units to be cut off after the DC blocking fault in order to keep the frequency of the AC system stabled-PΔ。
After the direct current blocking fault occurs, the power angle of the fire generator set in the power grids on two sides of the alternating current outgoing channel is unstable, wherein a converter station near-zone system is defined as an alternating current transmitting end power grid, and the other side of the alternating current channel is defined as an alternating current receiving end power grid. In order to ensure the power angle of the alternating current system to be stable after the direct current blocking fault, the direct current matched thermal power and the residual thermal power generating units in the alternating current transmission end power grid need to be cut off as soon as possible, and the power of the thermal power generating units is supposed to be cut off with the first priority of the alternating current transmission end power grid after the direct current blocking fault, wherein the power of the thermal power generating units is P1。
Further, the power P of the thermal power generating unit is cut off at the first priority1Greater than or equal to total amount P of unitd-PΔUnder the condition of (1), determining that the power P of the thermal power generating unit is cut off with first priority1The power angle and frequency are stable. If P is1≥Pd-PΔAnd the cutting amount is the minimum cutting measure for ensuring the power angle stability and the frequency stability. Cutting off power P of thermal power generating unit at first priority1Less than total amount P of unitd-PΔUnder the condition of (3), the machine cutting amount is increased to ensure the frequency stability of the alternating current system after the direct current locking fault.
For example, referring to fig. 3, fig. 3 is a schematic diagram of an ac/dc combined external transmission system in an energy base in China, where area a is rich in medium-voltage and new energy resources, and is transmitted to area B through one extra-high voltage dc (UHVDC is ± 800kV, 8000MW rated) and an ac transmission channel (DJ-FX double-circuit 750kV line + YH-LC double-circuit 750kV line), where area a is an ac transmitting-end power grid and area B is an ac receiving-end power grid. The matching A, the matching B, the matching C, the matching D and the matching E are all matching power supplies of UHVDC, and the total installed capacity is 7960 MW. According to simulation results and actual knowledge of a power grid, the maximum bearable power unbalance amount of the alternating current system is 2100 MW.
Considering a direct-current matching power supply and a live-wire full-starting mode in area A, when the UHVDC runs at 8000MW, the UHVDC is constrained by the three-permanent-N-1 fault of an alternating-current system, the sending capacity of a DJ-FX double + YH-LC double-circuit line is 2500MW, and the output of new energy in corresponding area A is 2950 MW. In this way, if a bipolar latching fault occurs in the UHVDC, power angle instability of the area a with respect to the area B generator set is caused, and the frequency of the ac system is greatly increased. Fig. 4 is a power angle curve of area a versus area B after a dc bipolar latch-up failure.
And calculating the total amount of the units which need to be cut off to ensure the stable system frequency after the direct current bipolar locking fault is 8000MW-2100 MW-5900 MW.
In order to ensure that the power angle and the frequency of the alternating current system are stable after the direct current blocking fault, the method comprises the following two steps:
(1) the cutting machine is used for ensuring the stability of the power angle after the fault.
In order to ensure that the power angle of the alternating current power grid is stable after the direct current blocking fault, the thermal power generating unit of the power grid at the transmitting end needs to be cut as soon as possible, and calculation shows that 4300MW is needed for cutting the matching and area A medium-power generating units. FIG. 5 is a power angle plot of area A versus area B after a DC bipolar latch-up failure, after a cutter 4300MW was taken.
(2) The cutting machine is used for ensuring the frequency stability after the fault.
Because the number of machine cutting machines ensuring stable power angle in the step (1) is less than the total number of machine cutting machines ensuring stable frequency, the frequency stability after the fault can be ensured only by cutting the machine units in the network, inertia and voltage support are provided for the power grid for reserving the thermal power generating units as much as possible, and at the moment, wind power and photovoltaic machine units in area A and area B are preferentially selected to be cut off. In this way, the total output of the new energy in the area A is 2950MW, and 1600MW photovoltaic units can be cut out.
Therefore, the optimized cutting method of the strong weak cross-linking and outward conveying system after direct current locking is adopted. The method comprises the steps of firstly analyzing effectiveness of generator tripping positions for ensuring power angle stability and frequency stability after direct current blocking faults respectively, preferably providing generator tripping measures aiming at power angle instability after faults, further providing additional generator tripping measures aiming at frequency stability problems, and providing an optimization method for safety control generator tripping after direct current blocking faults from the viewpoint of avoiding secondary problems such as steady-state overvoltage and the like caused after generator tripping.
And the technical problems that the safety of the converter station and the near-zone voltage or the voltage instability of a local area and the like caused by the great reduction of the short-circuit capacity of the converter station after the safety control switching-off machine after the direct-current blocking fault exists in the prior art and the stability of the power angles at two sides of the alternating-current section is deteriorated due to the improper position of the frequency stabilization switching-off machine are solved.
Optionally, the strong and weak cross-linking combined delivery system includes a dc transmission system and an ac system, the ac system includes an ac sending end power grid and an ac receiving end power grid, and after a dc blocking fault, power angle instability of the fire power generation set in the power grids on both sides of the ac delivery channel is caused, where the system in the vicinity of the converter station is the ac sending end power grid, and the other side of the ac channel is defined as the ac receiving end power grid.
Optionally, determining, according to the operation state, a loss amount of dc power transmitted by the dc power transmission system before the dc blocking fault and after the dc blocking fault includes: according to the operation state, determining the active power transmitted by the direct current transmission system before the direct current blocking fault and the active power transmitted by the direct current transmission system after the direct current blocking fault; and determining the direct current power loss amount before and after the direct current blocking fault according to the active power transmitted by the direct current power transmission system before the direct current blocking fault and the active power transmitted by the direct current power transmission system after the direct current blocking fault.
Optionally, when the first priority cut-off of the thermal power generating unit is smaller than the total amount of the thermal power generating unit, increasing the cut-off amount to ensure the frequency stability of the ac system after the dc blocking fault includes: and under the condition that the power of the thermal power generating unit is cut off preferentially to be smaller than the total power of the thermal power generating unit, determining the power of the cut-off new energy source unit according to the new energy source unit of the alternating current transmitting end power grid and the new energy source unit of the alternating current receiving end power grid.
Specifically, the power P of the thermal power generating unit is cut off at the first priority1Less than total amount P of unitd-PΔUnder the condition of (1), determining the power P of the removed new energy source unit according to the new energy source unit of the alternating current transmitting end power grid and the new energy source unit of the alternating current receiving end power grid2The new energyPower P of source unit2The sum of the power of the new energy source unit of the alternating current transmitting end power grid and the power of the new energy source unit of the alternating current receiving end power grid.
Optionally, when the first priority cut-off of the thermal power generating unit is smaller than the total amount of the thermal power generating unit, increasing the cut-off amount to ensure the frequency stability of the ac system after the dc blocking fault, further comprising: determining the sum of the power of the new energy unit and the power of the first prior cutoff thermal power generating unit; and determining that the alternating current system is stable under the condition that the sum of the power of the new energy source unit and the power of the first priority cutoff thermal power generating unit is larger than or equal to the total amount of the units.
In particular, the new energy bank power P is determined2Cutting off power P of thermal power generating unit with first priority1Summing; and at the new energy unit power P2Cutting off power P of thermal power generating unit with first priority1The sum is more than or equal to the total amount P of the unitd-PΔIn the case of (2), it is determined that the ac system is stable.
Optionally, when the first priority cut-off of the thermal power generating unit is smaller than the total amount of the thermal power generating unit, increasing the cut-off amount to ensure the frequency stability of the ac system after the dc blocking fault, further comprising: determining the power of a second thermal power generating unit of the alternating current transmission end power grid under the condition that the sum of the power of the new energy source unit and the power of the first priority cutoff thermal power generating unit is smaller than the total amount of the units; determining the sum of the power of the new energy unit, the power of the first priority cut-off thermal power generating unit and the power of the second priority cut-off thermal power generating unit; and determining that the alternating current system is stable under the condition that the sum of the power of the new energy source unit, the power of the first priority cutoff thermal power generating unit and the power of the second priority cutoff thermal power generating unit is larger than or equal to the total amount of the units.
In particular, at the new energy bank power P2The sum of the power of the thermal power generating unit and the first priority cut-off power is less than the total amount P of the thermal power generating unitd-PΔUnder the condition of (1), determining the second priority of the alternating current transmission end power grid to cut off the power P of the thermal power generating unit3And the power P of the thermal power generating unit is cut off firstly3The thermal power generating unit power is used for firstly cutting off the power of the thermal power generating unit for the second time of the alternating current sending end power grid after the direct current blocking fault in order to ensure that the power angle of the alternating current system is stable after the direct current blocking fault; determining new energy module functionRate P2The power P of the thermal power generating unit is cut off firstly1And the second priority cuts off the power P of the thermal power generating unit3Summing; and at the new energy unit power P2The power P of the thermal power generating unit is cut off firstly1And the second priority cuts off the power P of the thermal power generating unit3The sum is more than or equal to the total amount P of the unitd-PΔIn the case of (2), it is determined that the ac system is stable.
Therefore, the method for optimizing the cutting machine after direct current locking by the strong and weak cross-linking and outward conveying system is adopted. The method comprises the steps of firstly analyzing effectiveness of generator tripping positions for ensuring power angle stability and frequency stability after direct current blocking faults respectively, preferably providing generator tripping measures aiming at power angle instability after faults, further providing additional generator tripping measures aiming at frequency stability problems, and providing an optimization method for safety control generator tripping after direct current blocking faults from the viewpoint of avoiding secondary problems such as steady-state overvoltage and the like caused after generator tripping.
And the technical problems that the safety of the converter station and the near-zone voltage or the voltage instability of a local area and the like caused by the great reduction of the short-circuit capacity of the converter station after the safety control switching-off machine after the direct-current blocking fault exists in the prior art and the stability of the power angles at two sides of the alternating-current section is deteriorated due to the improper position of the frequency stabilization switching-off machine are solved.
According to another aspect of this embodiment, a system 600 is provided for cutting a rigid weak cross-linking delivery system after DC blocking. The system 600 includes: a power loss determining module 610, configured to monitor an operating state of the dc power transmission system in real time, and determine, according to the operating state, a dc power loss amount transmitted by the dc power transmission system before and after the dc blocking fault; a unit total amount determining module 620, configured to determine, according to the amount of dc power loss and the maximum power imbalance that can be borne by the power grid, a total amount of units that need to be removed to keep the frequency of the ac system stable after the dc blocking fault; determining a first priority thermal power unit power removal module 630, configured to determine a first priority thermal power unit power removal of the ac sending-end power grid after the dc blocking fault, where the first priority thermal power unit power removal is used to ensure that the power angle of the ac system is stable after the dc blocking fault, and the thermal power unit power of the ac sending-end power grid after the dc blocking fault is removed first time; a determining machine switching amount module 640, configured to determine that the power of the first priority cut thermal power generating unit is the machine switching amount that ensures stable power angle and stable frequency when the power of the first priority cut thermal power generating unit is greater than or equal to the total amount of the thermal power generating units; and an increase generator tripping amount module 650, configured to increase a generator tripping amount to ensure that the frequency of the ac system is stable after the dc blocking fault, when the first priority is to cut off the power of the thermal power generating unit less than the total power of the thermal power generating unit.
Optionally, the determining power loss amount module 610 includes: the active power sub-module is used for determining the active power transmitted by the direct current power transmission system before the direct current blocking fault and the active power transmitted by the direct current power transmission system after the direct current blocking fault according to the operation state; and the power loss determining submodule is used for determining the direct current power loss before and after the direct current blocking fault according to the active power transmitted by the direct current power transmission system before the direct current blocking fault and the active power transmitted by the direct current power transmission system after the direct current blocking fault.
Optionally, the increase amount of cutting module 650 includes: and determining a power submodule of the new energy source unit, and determining the power of the removed new energy source unit according to the new energy source unit of the alternating current transmitting end power grid and the new energy source unit of the alternating current receiving end power grid under the condition that the power of the thermal power generating unit is cut to be smaller than the total power of the units preferentially.
Optionally, the increase cutting amount module 650 further includes: the first power sum submodule is used for determining the sum of the power of the new energy source unit and the power of the first prior cutoff thermal power generating unit; and the first stability determining submodule is used for determining that the alternating current system is stable under the condition that the sum of the power of the new energy unit and the power of the first priority cut-off thermal power generating unit is greater than or equal to the total amount of the units.
Optionally, the increase cutting amount module 650 further includes: determining a second-priority thermal power unit power removal submodule for determining second-priority thermal power unit power removal of the alternating-current transmission end power grid under the condition that the sum of the new energy power unit power and the first-priority thermal power unit power removal is smaller than the total power unit amount, wherein the second-priority thermal power unit power removal is used for ensuring that the power angle of the alternating-current system is stable after the direct-current blocking fault, and the second-priority thermal power unit power removal of the alternating-current transmission end power grid after the direct-current blocking fault is performed; the second power sum submodule is used for determining the sum of the power of the new energy source unit, the power of the first priority cutoff thermal power generating unit and the power of the second priority cutoff thermal power generating unit; and the second determining and stabilizing submodule is used for determining that the alternating current system is stable under the condition that the sum of the new energy unit power, the first priority cut-off thermal power generating unit power and the second priority cut-off thermal power generating unit power is larger than or equal to the total amount of the thermal power generating units.
The system 600 for cutting the rigid weak cross-linking outgoing system after dc blocking according to the embodiment of the present invention corresponds to the method for cutting the rigid weak cross-linking outgoing system after dc blocking according to another embodiment of the present invention, and is not described herein again.
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 scheme in the embodiment of the application can be implemented by adopting various computer languages, such as object-oriented programming language Java and transliterated scripting language JavaScript.
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.
While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.
Claims (11)
1. A method for optimizing a cutter of a strong weak cross-linking and outward-conveying system after direct current blocking is characterized by comprising the following steps:
monitoring the running state of the direct current transmission system in real time, and determining the direct current power loss amount transmitted by the direct current transmission system before and after the direct current lockout fault according to the running state;
determining the total amount of the units which need to be cut off after the direct current blocking fault in order to keep the frequency of the alternating current system stable according to the direct current power loss and the maximum power unbalance amount which can be borne by the power grid;
determining first priority cut-off thermal power generating unit power of an alternating current sending end power grid after the direct current blocking fault, wherein the first priority cut-off thermal power generating unit power is used for ensuring that the power angle of an alternating current system is stable after the direct current blocking fault, and the thermal power generating unit power of the alternating current sending end power grid after the direct current blocking fault is cut off for the first time;
determining the power of the first priority cut thermal power generating unit to be a cut amount which ensures stable power angle and stable frequency under the condition that the power of the first priority cut thermal power generating unit is greater than or equal to the total amount of the thermal power generating units; and
and under the condition that the power of the first priority cutoff thermal power generating unit is smaller than the total amount of the thermal power generating units, increasing the machine switching amount to ensure the stable frequency of the alternating current system after the direct current blocking fault.
2. The method according to claim 1, wherein the strong weak cross-linking and sending system comprises the direct current transmission system and the alternating current system, the alternating current system comprises the alternating current sending end power grid and an alternating current receiving end power grid, and the power angle instability of the fire electric generating set in the power grids on two sides of the alternating current sending channel is caused after the direct current blocking fault, wherein the converter station near-zone system is the alternating current sending end power grid, and the other side of the alternating current channel is defined as the alternating current receiving end power grid.
3. The method of claim 1, wherein determining, based on the operating state, an amount of DC power loss delivered by the DC power transmission system before and after the DC blocking fault comprises:
according to the operation state, determining the active power transmitted by the direct current transmission system before the direct current blocking fault and the active power transmitted by the direct current transmission system after the direct current blocking fault; and
and determining the direct current power loss amount before and after the direct current blocking fault according to the active power transmitted by the direct current power transmission system before the direct current blocking fault and the active power transmitted by the direct current power transmission system after the direct current blocking fault.
4. The method of claim 3, wherein in the event that the first priority cutoff thermal power generating unit power is less than the total unit capacity, increasing a cutoff amount to ensure AC system frequency stability after DC blocking fault, comprises:
and under the condition that the power of the first priority cut-off thermal power generating unit is smaller than the total amount of the thermal power generating units, determining the power of the cut-off new energy source unit according to the new energy source unit of the alternating current transmitting end power grid and the new energy source unit of the alternating current receiving end power grid.
5. The method of claim 4, wherein in the case that the first priority cut-off thermal power generating unit power is less than the total unit amount, increasing a cut-off amount to ensure the frequency of the alternating current system to be stable after the direct current blocking fault, further comprising:
determining the sum of the power of the new energy unit and the power of the first priority cutoff thermal power generating unit; and
and determining that the alternating current system is stable under the condition that the sum of the power of the new energy unit and the power of the first priority cutoff thermal power generating unit is greater than or equal to the total amount of the units.
6. The method of claim 5, wherein in the event that the first priority cutoff thermal power generating unit power is less than the total unit capacity, increasing a cutoff amount to ensure AC system frequency stability after DC blocking fault, further comprising:
determining second priority thermal power unit cutting power of the alternating current sending end power grid under the condition that the sum of the new energy source unit power and the first priority thermal power unit cutting power is smaller than the total amount of the power units, wherein the second priority thermal power unit cutting power of the alternating current sending end power grid after the direct current blocking fault is used for ensuring the frequency stability and the power angle stability of an alternating current system after the direct current blocking fault, and the second priority thermal power unit cutting power of the alternating current sending end power grid after the direct current blocking fault;
determining the sum of the new energy unit power, the first priority cut-off thermal power generating unit power and the second priority cut-off thermal power generating unit power; and
and determining that the alternating current system is stable under the condition that the sum of the new energy unit power, the first priority cut-off thermal power generating unit power and the second priority cut-off thermal power generating unit power is larger than or equal to the total amount of the units.
7. The utility model provides a system of optimization cutter of strong weak cross-linking system of sending out after direct current shutting which characterized in that includes:
the power loss determining module is used for monitoring the running state of the direct current transmission system in real time and determining the direct current power loss transmitted by the direct current transmission system before and after the direct current lockout fault according to the running state;
the unit total amount determining module is used for determining the total amount of the units which need to be cut off after the direct current blocking fault in order to keep the frequency of the alternating current system stable according to the direct current power loss amount and the maximum power unbalance amount which can be borne by the power grid;
the method comprises the steps that a first priority thermal power unit power removal module is determined and is used for determining first priority thermal power unit power removal of an alternating current sending end power grid after direct current blocking faults, wherein the first priority thermal power unit power removal is used for ensuring that the power angle of an alternating current system is stable after the direct current blocking faults, and the first priority thermal power unit power removal of the alternating current sending end power grid after the direct current blocking faults is performed;
a generator tripping amount determining module, configured to determine that the power of the first priority thermal power generating unit is a generator tripping amount that ensures stable power angle and stable frequency when the power of the first priority thermal power generating unit is greater than or equal to the total amount of the thermal power generating units; and
and the generator tripping quantity increasing module is used for increasing the generator tripping quantity to ensure the frequency stability of the alternating current system after the direct current blocking fault under the condition that the first priority for cutting off the power of the thermal power generating unit is smaller than the total amount of the thermal power generating unit.
8. The system of claim 7, wherein the means for determining the amount of power loss comprises:
the active power sub-module is used for determining the active power transmitted by the direct current power transmission system before the direct current blocking fault and the active power transmitted by the direct current power transmission system after the direct current blocking fault according to the operation state; and
and the power loss determining submodule is used for determining the direct current power loss before and after the direct current blocking fault according to the active power transmitted by the direct current power transmission system before the direct current blocking fault and the active power transmitted by the direct current power transmission system after the direct current blocking fault.
9. The system of claim 8, wherein the increase cut amount module comprises:
and determining a new energy unit power submodule, which is used for determining the power of the removed new energy unit according to the new energy unit of the alternating current transmitting end power grid and the new energy unit of the alternating current receiving end power grid under the condition that the power of the first priority removed thermal power generating unit is smaller than the total amount of the thermal power generating units.
10. The system of claim 9, wherein the increase generator tripping amount module further comprises:
a first power sum submodule is determined and used for determining the sum of the new energy unit power and the first priority cut-off thermal power generating unit power; and
and the first stability determining submodule is used for determining that the alternating current system is stable under the condition that the sum of the new energy unit power and the first priority cut-off thermal power generating unit power is larger than or equal to the total amount of the units.
11. The system of claim 10, wherein the increase generator tripping amount module further comprises:
determining a second-priority-cut-off thermal power generating unit power submodule, which is used for determining the second-priority-cut-off thermal power generating unit power of the alternating-current sending-end power grid under the condition that the sum of the new energy unit power and the first-priority-cut-off thermal power generating unit power is smaller than the total power generating unit amount, and is used for ensuring the second-priority-cut-off thermal power generating unit power of the alternating-current sending-end power grid after the direct-current blocking fault in order to ensure the frequency stability and the power angle stability of an alternating-current system after the direct-current blocking fault;
a second power sum submodule is determined and used for determining the sum of the new energy unit power, the first priority cut-off thermal power generating unit power and the second priority cut-off thermal power generating unit power; and
and the second stability determining submodule is used for determining that the alternating current system is stable under the condition that the sum of the new energy unit power, the first priority cut-off thermal power generating unit power and the second priority cut-off thermal power generating unit power is larger than or equal to the total amount of the units.
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| CN109802417A (en) * | 2017-11-16 | 2019-05-24 | 中国电力科学研究院有限公司 | Reply DC Line Fault impacts the power grid emergency control method and device of weak communication channel |
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