CN114039362A - Combined stability control method and device for power system - Google Patents

Combined stability control method and device for power system Download PDF

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Publication number
CN114039362A
CN114039362A CN202111010635.6A CN202111010635A CN114039362A CN 114039362 A CN114039362 A CN 114039362A CN 202111010635 A CN202111010635 A CN 202111010635A CN 114039362 A CN114039362 A CN 114039362A
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branch
node
phase
node pair
power system
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郑超
孙华东
曲仝
陈怡君
李惠玲
吕思卓
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China Electric Power Research Institute Co Ltd CEPRI
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China Electric Power Research Institute Co Ltd CEPRI
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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
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H02J3/241—The oscillation concerning frequency
    • 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
    • H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
    • H02J3/144—Demand-response operation of the power transmission or distribution network
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
    • 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
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems
    • Y04S20/222—Demand response systems, e.g. load shedding, peak shaving

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Abstract

The invention discloses a combined stability control method of an electric power system and equipment with the combined stability control method, wherein the combined stability control method of the electric power system respectively determines a remote node pair and a key branch node pair by measuring the resistance, the voltage amplitude and the voltage phase of nodes in the system, identifies the running state of a power grid by processing and calculating characteristic data of the two nodes, and takes corresponding control measures. The method utilizes the characteristics of the concave-convex characteristic of the phase frequency track to increase the agility and the reliability of the joint stable control of the power system.

Description

Combined stability control method and device for power system
Technical Field
The invention relates to the field of safety and stability analysis of power systems, in particular to a joint stability control method and device for response information based on wide-area characteristic nodes.
Background
Under the influence of factors such as large-scale grid connection of new energy units such as wind power, photovoltaic and the like, large-scale operation of high-capacity extra-high voltage direct-current transmission projects, continuous increase of novel loads of electric automobiles and the like, the transient power angle stability characteristic of a power system is deeply changed, and new requirements and challenges are provided for power angle stability analysis and control technologies of power grids in China. At present, an 'off-line calculation and implementation matching' control mode widely adopted in China is difficult to deal with actual fault conditions with large matching errors with a preset control strategy table, and a stability control measure is invalid, so that system disconnection is finally even caused, and a large-area power failure accident occurs. To avoid this situation, it is necessary to evaluate the transient stability of the power angle of the system on line and take emergency control measures in time when the pre-determined system is about to be unstable, so as to restore the power angle of the system to be stable and prevent the fault situation from further expanding.
The WAMS can provide abundant large-disturbance transient response information and provides technical support for real-time stability analysis and control of a response-based power system. Among various stability pre-judging methods, stability judgment based on response trajectory features has the technical advantages of simple criterion construction, high judgment speed, high judgment accuracy and the like, and is widely concerned. The key of the transient stability control is characterized in that the characteristic electrical quantity identification and the instability criterion construction are carried out. When power angle instability occurs in a power grid, the electric quantity response tracks of some nodes and lines show obvious difference characteristics, and the electric quantity response tracks can be used as characteristic quantities for power angle instability prejudgment, so that the identification process of the characteristic quantities during power grid disturbance is called as characteristic electric quantity identification. The instability criterion refers to a criterion for judging whether power angle instability of the power grid occurs or is about to occur, is usually in a self-defined form of one or more quantitative calculation indexes based on characteristic electrical quantities, and is called to take effect when the indexes meet certain conditions in numerical value. Transient stability analysis and control methods based on response trajectory features can be divided into two categories, namely, a unit-based response trajectory and a network-based response trajectory, according to WAMS sampling information sources. The unit response track-based method comprises the steps of acquiring unit power, power angle, angular speed and the like as characteristic electrical quantity response data, and acquiring node voltage phase, frequency and the like electrical quantity response data.
The instability judging method based on the unit response track generally depends on the real-time grouping and phase track segmentation aggregation results of the generators, and unreasonable coherent grouping results can cause system stability misjudgment and cause misoperation of a stability control device. In the aspect of judging the instability of the system based on the network response track, the existing method has the problems of difficult setting of a judging threshold value, misjudgment of power angle instability of a non-coherent system in a group, short emergency control time margin and the like, so that the engineering application is difficult.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a combined stable control method for an electric power system, which can provide an accurate and agile electric power system control method and is suitable for an electric power system with complex components.
The invention also provides equipment, a terminal and a storage medium with the power system joint stability control method.
According to a first aspect of the present invention, a power system joint stability control method is provided, which includes the steps of:
measuring the voltage phase of each node in the system, and identifying a farthest distance node pair according to the voltage phase of each node;
measuring the voltage amplitude and the voltage phase of each branch in the system, and calculating the transient transmission capacity index of each simplified branch according to the voltage amplitude and the voltage phase;
identifying key branch node pairs according to the simplified branch transient state power transmission capacity index of each branch;
extracting the phase difference and the frequency difference of the farthest distance node pair, and extracting the phase difference and the frequency difference of the key branch node pair;
judging whether the transient state of the power system is stable or not according to the frequency difference of the key branch node pair and the frequency difference of the farthest node pair;
if the power system is in the condition of power angle instability, respectively carrying out quadratic curve fitting on the phase-frequency sampling filtering data of the key branch node pair and the farthest distance node pair by adopting a least square method to obtain a piecewise fitting phase-frequency track at the current moment;
calculating the concave-convex coefficient of the phase frequency track of the farthest distance characteristic node pair and the key branch node pair;
judging whether power angle instability occurs in the power system according to the concave-convex characteristics of the phase frequency tracks of the farthest distance characteristic node pairs and the key branch node pairs;
if the power angle of the power system is unstable, measures of emergency power cutting and load shedding and direct current power control are taken for the power system.
The combined stable control method of the power system according to the embodiment of the invention at least has the following beneficial effects: NP with farthest node pairsmθAnd a critical branch node pair NPkbIdentifying, and respectively identifying two types of characteristic node pairs by using the maximum and minimum phase tracks and the sBTTC index curve as judgment bases, wherein in the aspect of a instability criterion construction method, the equipment utilizes the maximum and minimum distance node pair NPmθAnd a critical branch node pair NPkbThe phase frequency track concavity and convexity are used as a stability criterion, and due to the rapidity advantage of track concavity and convexity judgment, the transient stability emergency control can be implemented in time, so that the method has quite high accuracy and agility.
According to some embodiments of the invention, the method starts after waiting a preset time before starting.
According to some embodiments of the present invention, the step of measuring the voltage phase of each node in the system and identifying the farthest node pair according to the voltage phase of each node specifically includes:
measuring the voltage phase of each node in the system;
and sequencing each node according to the voltage phase of each node, and taking the node with the maximum voltage phase and the node with the minimum voltage phase as a farthest distance node pair.
According to some embodiments of the present application, the step of identifying a key branch node pair according to the simplified branch transient transmission capability index of each branch comprises:
sorting the transient state transmission capacity indexes of the simplified branches of each branch according to the size;
and taking the branch with the minimum simplified branch transient state transmission capacity index as a key branch, and taking nodes on two sides of the key branch as key branch node pairs.
According to some embodiments of the present application, the simplified branch transient transmission capability index sBTTC is calculated by:
Figure BDA0003238846270000031
wherein subscripts m and n respectively represent tributary BRmnTwo end measurement nodes, UmIs a branch BRmnAmplitude of voltage at upper node m, UnIs a branch BRmnAmplitude of voltage at upper node n, thetamIs a branch BRmnPhase of voltage at upper node m, thetanIs a branch BRmnThe voltage phase of the upper node n.
According to some embodiments of the present application, the step of determining the destabilization state of the power system according to the change of the frequency difference of the key branch node pair and the frequency difference of the farthest node pair specifically includes:
and when the frequency difference of the key branch node pair and the frequency difference of the farthest distance node pair do not change the frequency symbol, the power angle instability of the power system occurs, otherwise, the power system operates normally.
According to a second aspect of the present invention, a power system joint stability control apparatus is provided, including:
the farthest distance node pair identification module can measure the voltage phase of each node in the system and identify the farthest distance node pair according to the voltage phase of each node;
the simplified branch transient state power transmission capacity calculation module can measure the voltage amplitude and the voltage phase of each branch in the system and calculate the simplified branch transient state power transmission capacity index of each branch according to the voltage amplitude and the voltage phase;
the key branch node pair identification module can identify a key branch node pair according to the simplified branch transient power transmission capacity index of each branch;
the phase difference and frequency difference extraction module can extract the phase difference and the frequency difference of the farthest distance node pair and extract the phase difference and the frequency difference of the key branch node pair;
the first stability judgment module judges whether the transient state of the power system is stable or not according to the frequency difference of the key branch node pair and the change of the frequency difference of the farthest distance node pair;
the phase frequency fitting module is used for respectively performing quadratic curve fitting on the phase-frequency sampling filtering data of the key branch node pair and the farthest distance node pair by adopting a least square method to obtain a piecewise fitting phase frequency track at the current moment if the power system is in the condition of power angle instability;
the concave-convex coefficient calculation module can calculate concave-convex coefficients of phase frequency tracks of the farthest distance characteristic node pairs and the key branch node pairs;
the second stability judgment module can judge whether the power angle instability of the power system occurs according to the concave-convex characteristics of the phase frequency tracks of the farthest distance characteristic node pair and the key branch node pair;
and the emergency control module is used for taking measures of emergency power-off load cutting and direct-current power control on the power system if the power angle of the power system is unstable.
The combined stable control device of the power system according to the embodiment of the invention at least has the following beneficial effects: the method comprises the steps of respectively determining a key branch node pair and a farthest distance node pair through a farthest distance node pair identification module and a key branch node pair identification module, then determining the stable state of a system according to a simplified branch transient power transmission capacity calculation module, a phase difference frequency difference extraction module, a first stability judgment module, a phase frequency fitting module, a concave-convex coefficient calculation module and a second stability judgment module, and finally processing the power system through an emergency control module.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
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The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic step diagram of a power system joint stability control method according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
With the increasing proportion of clean energy in the power system, the components of the power system become more complex, and when the power system is unstable, if no measures are taken, the system may be disconnected, and even a large-scale power failure may occur. There is a need for an agile and efficient power system control method.
The first embodiment,
Referring to fig. 1, an embodiment of the present application provides a power system joint stability control method, including the following steps:
and step S100, waiting for a preset time.
The power system joint stability control method described in the present application is arranged in a power system, and needs to monitor the system for a long time, so the method needs to be arranged to operate circularly. So at the beginning of the step, i.e. at the end of the last cycle. Typically the initial stage after the fault is cleared.
In order to avoid misjudgment of the subsequent judgment process caused by insufficient data in the initial stage during sampling, a preset waiting time is usually set, meanwhile, the execution time of a judgment process is also lengthened, and the pressure of the judgment process on the system is reduced.
Preferably, the control parameter T may be set firstc，TcAnd (4) sampling window time for the characteristic electrical quantity segmented phase-frequency trajectory fitting. If the current time is less than TcThen wait until the current time is greater than or equal to Tc。
And S200, measuring the voltage phase of each node in the system, and identifying the farthest distance node pair according to the voltage phase of each node.
Measuring voltage phase theta of each node i in power systemiAnd identifying the farthest distance node pair according to the voltage phase of each node. The method specifically comprises the following steps:
and step S201, measuring the voltage phase of each node in the system.
For a power system, where all node sets are denoted Nnode. Measuring the voltage phase θ of each node ii，i∈Nnode。
Step S202, sequencing each node according to the voltage phase of each node, and taking the node with the maximum voltage phase and the node with the minimum voltage phase as a farthest distance node pair.
According to the formula (1), the voltage phases of all nodes are sorted from small to large, a maximum phase node p and a minimum phase node q are extracted, and a node pair NP formed by the maximum phase node p and the minimum phase node q ispqIdentified as a furthest away node pair NPm。
Figure BDA0003238846270000071
Wherein, thetapq＝|θp-θq|(NPpq∈N2 node，N2 nodeFor a set of node pairs within a system) represents a node pair NPpqPhase difference of the node voltages on the two sides. ThetapIs the voltage phase of node p, θqIs the voltage phase at node q.
Step S300, measuring the voltage amplitude and the voltage phase of each branch in the system, and calculating the transient state transmission capacity index of each branch according to the voltage amplitude and the voltage phase.
For each tributary BRmn，(BRmn∈Nline，NlineFor a set of branches within a system) measures the voltage amplitude U at nodes m and n across itm、UnAnd voltage phase thetamn. An sBTTC (simplified Branch Transient Transmission Capability index) index of each Branch BRmn is calculated according to equation (2).
Figure BDA0003238846270000072
Wherein, thetamn＝|θm-θn|(BRmn∈Nline) Indicating branch BRmnThe phase difference of the voltages of the nodes at the two ends. Subscripts m, n denote branches BRmnTwo ends measure the nodes. U shapemIs a branch BRmnAmplitude of voltage at upper node m, UnIs a branch BRmnAmplitude of voltage at upper node n, thetamIs a branch BRmnPhase of voltage at upper node m, thetanIs a branch BRmnThe voltage phase of the upper node n.
And S400, identifying key branch node pairs according to the simplified branch transient state power transmission capacity index of each branch.
According to some preferred embodiments of the present application, the steps specifically include:
step S401, the transient state power transmission capacity indexes of the simplified branches are sorted according to the size.
Ranking each branch sBTTC index from small to large according to equation (3):
Figure BDA0003238846270000081
and S402, taking the branch with the minimum simplified branch transient state power transmission capacity index as a key branch, and taking nodes on two sides of the key branch as key branch node pairs.
Identifying the branch with the smallest sBTTC index value as the critical branch BRkbMarking branch BRkbThe node pair formed by the nodes at two ends is a key branch node pair NPkb。
Step S500, extracting the phase difference and the frequency difference of the farthest distance node pair, and extracting the phase difference and the frequency difference of the key branch node pair.
When determining the farthest distance node NPkbAnd a critical branch node pair NPmθThereafter, they are extracted for the preceding waiting period TcPhase-frequency sampling of the filtered data thetakb、fkb、θmθ、fmθ。
Wherein, thetakbRepresenting a key branch node pair NPkbPhase difference of node voltages at both sides, fkbRepresenting a key branch node pair NPkbFrequency difference of node voltages on both sides, thetamθRepresenting a furthest away node pair NPmθPhase difference of node voltages at both sides, fmθRepresenting a furthest away node pair NPmθThe difference in frequency between the node voltages on both sides.
And S600, judging whether the transient state of the power system is stable or not according to the frequency difference of the key branch node pair and the frequency difference of the farthest node pair.
When the power system is stable, the frequency symbol of the wide area node pair is changed at a certain moment, and the corresponding phase frequency track crosses the abscissa axis.
If a destabilization condition occurs when the power system is disturbed, the frequency sign of the wide area node pair does not change during the disturbance. Whether the transient stability of the power grid occurs can be judged by the following formula (4):
Figure RE-GDA0003462015940000082
and if the state of the power grid is in a condition of satisfying the formula 4, indicating that the power system is unstable, and entering the next step. If the formula 4 is not satisfied, the power system is stable in operation, and the process is ended.
And S700, respectively carrying out quadratic curve fitting on the phase-frequency sampling filtering data of the key branch node pair and the farthest distance node pair by adopting a least square method, and obtaining a piecewise fitting phase-frequency track at the current moment.
And (3) respectively carrying out quadratic curve fitting on the phase-frequency sampling filtering data of the key branch node pair and the farthest distance node pair by a formula (5):
Figure BDA0003238846270000092
wherein f iskbf(t) represents the critical branch at the current time tNode pair NPkbFrequency value on piecewise fitting curve, fmθf(t) represents the farthest node pair NP at time tmθFrequency values on the piecewise fitting curve, a, b and c are coefficients of each secondary term of the fitting curve respectively, subscripts k and m represent key branch node pairs NP respectivelykbAnd a farthest node pair NPmθ。
And step S800, calculating the concave-convex coefficient of the phase frequency track of the farthest distance characteristic node pair and the key branch node pair.
The formula used is as follows:
Figure BDA0003238846270000093
wherein, CkbRepresenting a key branch node pair NPkbCoefficient of concavity and convexity of (C)mθRepresenting the farthest distance node pair N PmθThe coefficient of concavity and convexity of (2).
And S900, judging whether the power angle instability of the power system occurs or not according to the concave-convex characteristics of the phase frequency tracks of the farthest distance characteristic node pairs and the key branch node pairs.
In order to increase the reliability of the algorithm and avoid misjudging the operation state of the power system, step S900 is introduced for further confirmation to ensure that power angle instability of the power system occurs, and emergency stability control is required.
When unbalanced power in the system cannot be timely absorbed, the power angle is continuously increased, the rotation speed difference between the units rapidly rises after being temporarily reduced, so that the power angle instability of the system occurs, and the power angle-rotation speed difference phase plane track between the units is subjected to concave-convex conversion in the disturbed period of the system. And because the phase-frequency response between the wide area node pair crossing the oscillation center and the unit group has consistent geometric characteristics, if the system has power angle instability, the key branch node pair NPkbAnd a farthest node pair NPmθThe phase frequency locus of (a) will exhibit a convex characteristic at a certain time. The judgment is according to reference formula (7):
Figure BDA0003238846270000101
when the equation (7) is not satisfied, it indicates that the power angle instability has not occurred in the system, and the process jumps back to step S100 to perform the next determination again.
If the equation (7) is met, the power angle instability of the system is generated, and emergency measures are required.
And S1000, if the power angle of the power system is unstable, taking measures of emergency power cutting load cutting and direct current power control on the power system.
When the above procedure determines that power angle instability occurs in the power system, measures of emergency tripping load shedding and direct current power are used for the power system, the measures described herein are control methods commonly used in the art, and detailed descriptions of specific principles and operation modes are omitted.
Another embodiment of the present application provides a power system joint stability control apparatus, including: the system comprises a farthest distance node pair identification module, a simplified branch transient state power transmission capacity calculation module, a key branch node pair identification module, a phase difference frequency difference extraction module, a first stability judgment module, a phase frequency fitting module, a concave-convex coefficient calculation module, a second stability judgment module and an emergency control module.
The farthest distance node pair identification module can measure the voltage phase of each node in the system and identify the farthest distance node pair according to the voltage phase of each node;
the simplified branch transient state power transmission capacity calculation module can measure the voltage amplitude and the voltage phase of each branch in the system and calculate the simplified branch transient state power transmission capacity index of each branch according to the voltage amplitude and the voltage phase;
the key branch node pair identification module can identify a key branch node pair according to the simplified branch transient power transmission capacity index of each branch;
the phase difference and frequency difference extraction module can extract the phase difference and the frequency difference of the farthest distance node pair and extract the phase difference and the frequency difference of the key branch node pair;
the first stability judgment module judges whether the transient state of the power system is stable or not according to the frequency difference of the key branch node pair and the change of the frequency difference of the farthest distance node pair;
the phase frequency fitting module is used for respectively performing quadratic curve fitting on the phase-frequency sampling filtering data of the key branch node pair and the farthest distance node pair by adopting a least square method to obtain a piecewise fitting phase frequency track at the current moment if the power system is in the condition of power angle instability;
the concave-convex coefficient calculation module can calculate concave-convex coefficients of phase frequency tracks of the farthest distance characteristic node pairs and the key branch node pairs;
the second stability judgment module can judge whether the power angle instability of the power system occurs according to the concave-convex characteristics of the phase frequency tracks of the farthest distance characteristic node pair and the key branch node pair;
and the emergency control module is used for taking measures of emergency power-off load cutting and direct-current power control on the power system if the power angle of the power system is unstable.
The embodiment of the application provides a joint stability control method for response information based on wide area characteristic nodes. In the aspect of characteristic electrical quantity identification, the application defines two characteristic electrical quantities, namely a farthest distance node pair NPmθAnd a critical branch node pair NPkbIt is proposed to identify two types of feature node pairs using the maximum and minimum phase trajectories and the sBTTC index curves, respectively. In the aspect of a instability criterion construction method, the patent provides an NP (network processor) based on a remote node pairmθAnd a critical branch node pair NPkbThe stability criterion of the unevenness of the phase frequency track is characterized in that due to the rapidity advantage of the judgment of the unevenness of the track, the emergency control of the transient stability can be implemented in time, and the accuracy is quite high.
An embodiment of the present application provides a terminal, including: the system comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor executes the computer program to realize the power system joint stability control method.
In particular, the processor may be a CPU, general purpose processor, DSP, ASIC, FPGA or other programmable logic device, transistor logic device, hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. A processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, a DSP and a microprocessor, or the like.
In particular, the processor is coupled to the memory via a bus, which may include a path for communicating information. The bus may be a PCI bus or an EISA bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc.
The memory may be, but is not limited to, a ROM or other type of static storage device that can store static information and instructions, a ram or other type of dynamic storage device that can store information and instructions, an EEPROM, a CD-ROM or other optical disk storage, optical disk storage (including compact disk, laser disk, optical disk, digital versatile disk, blu-ray disk, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
Optionally, the memory is used for storing codes of computer programs for executing the scheme of the application, and the processor is used for controlling the execution. The processor is used for executing the application program codes stored in the memory so as to realize the action of the power system joint stable control of the application program provided by the embodiment shown in the figure 1.
An embodiment of the present application provides a computer-readable storage medium, which stores computer-executable instructions for executing the power system joint stability control method of the application program shown in fig. 1.
The embodiment of the application is based on the joint stability control equipment of the wide area characteristic node for the response information. NP with farthest node pairsmθAnd a critical branch node pair NPkbIdentification is carried out, and the identification of two types by utilizing the maximum and minimum phase tracks and the sBTTC index curve respectively is proposedThe characteristic node pair is used as a judgment basis, and in the aspect of a instability criterion construction method, the equipment is used for carrying out node pair NP by using the farthest distancemθAnd a critical branch node pair NPkbThe phase frequency track concavity and convexity are used as a stability criterion, and due to the rapidity advantage of track concavity and convexity judgment, the transient stability emergency control can be implemented in time, so that the method has quite high accuracy and agility.
One of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as is well known to those of ordinary skill in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by a computer. In addition, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media as known to those skilled in the art.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.

Claims (7)

1. A combined stability control method for a power system is characterized by comprising the following steps:
measuring the voltage phase of each node in the system, and identifying a farthest distance node pair according to the voltage phase of each node;
measuring the voltage amplitude and the voltage phase of each branch in the system, and calculating the transient transmission capacity index of each simplified branch according to the voltage amplitude and the voltage phase;
identifying key branch node pairs according to the simplified branch transient state power transmission capacity index of each branch;
extracting the phase difference and the frequency difference of the farthest distance node pair, and extracting the phase difference and the frequency difference of the key branch node pair;
judging whether the transient state of the power system is stable or not according to the frequency difference of the key branch node pair and the frequency difference of the farthest node pair;
if the power system is in the condition of power angle instability, respectively carrying out quadratic curve fitting on the phase-frequency sampling filtering data of the key branch node pair and the farthest distance node pair by adopting a least square method to obtain a piecewise fitting phase-frequency track at the current moment;
calculating the concave-convex coefficient of the phase frequency track of the farthest distance characteristic node pair and the key branch node pair;
judging whether power angle instability occurs in the power system according to the concave-convex characteristics of the phase frequency tracks of the farthest distance characteristic node pairs and the key branch node pairs;
if the power angle of the power system is unstable, measures of emergency power cutting and load shedding and direct current power control are taken for the power system.
2. The power system joint stability control method of claim 1, wherein the method is started after waiting a preset time before starting.
3. The power system joint stability control method according to claim 1, wherein the step of measuring the voltage phase of each node in the system and identifying the farthest node pair according to the voltage phase of each node specifically comprises:
measuring the voltage phase of each node in the system;
and sequencing each node according to the voltage phase of each node, and taking the node with the maximum voltage phase and the node with the minimum voltage phase as a farthest distance node pair.
4. The method of claim 1, wherein the step of identifying key branch node pairs based on the simplified branch transient transmissibility index for each branch comprises:
sorting the transient state transmission capacity indexes of the simplified branches of each branch according to the size;
and taking the branch with the minimum simplified branch transient state transmission capacity index as a key branch, and taking nodes on two sides of the key branch as key branch node pairs.
5. The power system joint stability control method according to claim 1 or 4, wherein the simplified branch transient state power transmission capability index sBTTC is calculated by the following formula:
Figure FDA0003238846260000021
wherein subscripts m and n respectively represent tributary BRmnTwo end measurement nodes, UmIs a branch BRmnAmplitude of voltage at upper node m, UnIs a branch BRmnAmplitude of voltage at upper node n, thetamIs a branch BRmnPhase of voltage at upper node m, thetanIs a branch BRmnThe voltage phase of the upper node n.
6. The power system joint stability control method according to claim 1, wherein the step of determining the destabilization state of the power system according to the change of the frequency difference of the key branch node pair and the frequency difference of the farthest node pair specifically comprises:
and when the frequency difference of the key branch node pair and the frequency difference of the farthest distance node pair do not change the frequency symbol, the power angle instability of the power system occurs, otherwise, the power system operates normally.
7. An electric power system joint stability control device, comprising:
the farthest distance node pair identification module can measure the voltage phase of each node in the system and identify the farthest distance node pair according to the voltage phase of each node;
the simplified branch transient state power transmission capacity calculation module can measure the voltage amplitude and the voltage phase of each branch in the system and calculate the simplified branch transient state power transmission capacity index of each branch according to the voltage amplitude and the voltage phase;
the key branch node pair identification module can identify a key branch node pair according to the simplified branch transient power transmission capacity index of each branch;
the phase difference and frequency difference extraction module can extract the phase difference and the frequency difference of the farthest distance node pair and extract the phase difference and the frequency difference of the key branch node pair;
the first stability judgment module judges whether the transient state of the power system is stable or not according to the frequency difference of the key branch node pair and the change of the frequency difference of the farthest distance node pair;
the phase frequency fitting module is used for respectively performing quadratic curve fitting on the phase-frequency sampling filtering data of the key branch node pair and the farthest distance node pair by adopting a least square method to obtain a piecewise fitting phase frequency track at the current moment if the power system is in the condition of power angle instability;
the concave-convex coefficient calculation module can calculate concave-convex coefficients of phase frequency tracks of the farthest distance characteristic node pairs and the key branch node pairs;
the second stability judgment module can judge whether the power angle instability of the power system occurs according to the concave-convex characteristics of the phase frequency tracks of the farthest distance characteristic node pair and the key branch node pair;
and the emergency control module is used for taking measures of emergency power-off load cutting and direct-current power control on the power system if the power angle of the power system is unstable.
CN202111010635.6A 2021-08-31 2021-08-31 Combined stability control method and device for power system Pending CN114039362A (en)

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Publication number Priority date Publication date Assignee Title
CN116320043A (en) * 2023-05-24 2023-06-23 深圳龙电华鑫控股集团股份有限公司 Method and system for improving transmission efficiency of multi-carrier communication system

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Title
郑超等: "基于广域支路响应特征的失稳预判与紧急控制", 《中国电机工程学报》, vol. 41, no. 17, pages 5866 - 5877 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116320043A (en) * 2023-05-24 2023-06-23 深圳龙电华鑫控股集团股份有限公司 Method and system for improving transmission efficiency of multi-carrier communication system

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