CN108847692B - Method and system for improving static stability limit of large-area interconnected power grid tie line - Google Patents
Method and system for improving static stability limit of large-area interconnected power grid tie line 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
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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
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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
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Abstract
The invention discloses a method and a system for improving the static stability limit of a large-area interconnected network tie line, which comprises the following steps: equating the large-area interconnected power grid into a two-machine model by using a Thevenin equivalence method, and respectively determining Thevenin equivalent potentials of a transmitting-end power grid and a receiving-end power grid; determining a potential amplitude according to the Thevenin equivalent potentials of the transmitting end power grid and the receiving end power grid, comparing the potential amplitude with a preset threshold, and dividing the power grid of the region into two generator groups according to the internal transmission section of the regional power grid when the potential amplitude is smaller than the preset threshold; performing inertia center equivalence on the two clusters, and respectively calculating the rotating speed and the power angle of the leading generator cluster and the lagging generator cluster; the unit output of the leading generator group is reduced, the unit output of the lagging generator group is correspondingly increased, and the power angle difference of the two generator groups is reduced, so that the integral equivalent Thevenin potential amplitude of the regional power grid is increased, and the static stability limit of the regional interconnected power grid tie line is improved.
Description
Technical Field
The invention relates to the technical field of power systems, in particular to a method and a system for improving the static stability limit of a large-area interconnected power grid tie line.
Background
Aiming at the characteristic that energy resources and energy consumption are distributed reversely in regions, China vigorously pushes the development of extra-high voltage alternating current and direct current, realizes large-scale and large-scale resource optimization configuration, and exerts the advantages of extra-high voltage alternating current and direct current large-capacity and long-distance power transmission. In 2009, a Changzhi-south sun-Jingmen extra-high voltage alternating current test demonstration project is put into operation formally to form a North-China two major interconnected synchronous power system which comprises 12 provincial (municipal) power grids. In 2011, an extra-high voltage alternating current test demonstrates the formal commissioning of the engineering extension project, and the transmission capacity of the north-China central line is further improved. The safety and stability of the power system are specified in the guide rule: for a large power supply outgoing line, a large-area or provincial internetwork connecting line is crossed, and a weak section in a network and the like need to be subjected to static stability analysis. The transmission section static stability limit plays an important role in the operation personnel of the power system to master the transmission capacity of the transmission section.
The main idea for improving the static stability limit of a large-area interconnected power grid tie line is as follows: by reducing the electrical connection between the two regional power grids, such as newly building a parallel connection line, increasing series capacitance compensation and the like, the connection reactance of the interconnected power grids is reduced, so that the aim of improving the static stability limit is fulfilled. Under the condition that the grid structure of the power grid is determined, the condition that the static stability limit of the interconnected power grid in a large area is improved by adjusting the operation mode is not considered, so that the static safety stability margin of the power grid is ensured.
Therefore, a method for solving the problem of how to increase the static stability limit of the large interconnected area power grid in the actual operation of the power grid is needed.
Disclosure of Invention
The invention provides a method and a system for improving the static stability limit of a large-area interconnected network tie line, which aim to solve the problem of how to improve the static stability limit of the large-area interconnected network tie line.
In order to solve the above problem, according to an aspect of the present invention, there is provided a method for raising a static stability limit of a large area interconnected network tie, the method comprising:
equating the large-area interconnected power grid into a two-machine model by using a Thevenin equivalent method, and respectively determining the Thevenin equivalent potential of a transmitting-end power grid and the Thevenin equivalent potential of a receiving-end power grid;
determining a potential amplitude according to the Thevenin equivalent potential of the transmitting-end power grid and the Thevenin equivalent potential of the receiving-end power grid, comparing the potential amplitude with a preset threshold, and dividing the power grid of the region into two generator groups according to the internal transmission section of the region power grid when the potential amplitude is smaller than the preset threshold;
performing inertia center equivalence on the two clusters, and respectively calculating the rotating speed and the power angle of the leading generator cluster and the lagging generator cluster;
the unit output of the leading generator group is reduced, the unit output of the lagging generator group is correspondingly increased, and the power angle difference of the two generator groups is reduced, so that the integral equivalent Thevenin potential amplitude of the regional power grid is increased, and the static stability limit of the regional interconnected power grid tie line is improved.
Preferably, wherein the thevenin equivalent potential is determined using the formula:
wherein the content of the first and second substances,
is the thevenin equivalent potential of the external equivalent system at the moment k; zkIs the impedance of the same value as the impedance,
in order to be the bus voltage,
is the current injected into the bus.
Preferably, the rotation speed and power angle of the leading generator group are calculated using the following formulas:
wherein, ω issTo advance the speed of the generator group, deltasTo advance the power angle, omega, of the generator groupiFor leading the first in the generator groupRotational speed, delta, of i generator setsiThe power angle of the ith generator set in the advanced generator group is set, and S is the total number of the generator sets in the advanced generator group; mSTo advance the inertia time constant of the generator group, and
Mithe inertia time constant of the ith generating set in the leading generating set group.
Preferably, the rotation speed and the power angle of the lag generator group are calculated using the following equations:
wherein, ω isATo retard the speed of rotation, delta, of the generator groupAFor retarding the power angle, omega, of the generator groupjFor retarding the speed, delta, of the jth generator set in the generator groupjThe power angle of the jth generator set in the lag generator group is A, and the total number of the generator sets in the lag generator group is A; mAIs a lag of the inertia time constant of the generator group, and
Mjis the inertia time constant of the jth generating set in the lag generating set.
According to another aspect of the present invention, there is provided a system for raising the limit of static stability of a large area interconnected network tie, the system comprising:
the Thevenin equivalent potential determining unit is used for equating the large-area interconnected power grid into a two-machine model by utilizing a Thevenin equivalent method and respectively determining the Thevenin equivalent potential of a transmitting-end power grid and the Thevenin equivalent potential of a receiving-end power grid;
the generator group division unit is used for determining a potential amplitude according to the Thevenin equivalent potential of the transmitting-end power grid and the Thevenin equivalent potential of the receiving-end power grid, comparing the potential amplitude with a preset threshold value, and dividing the power grid of the region into two generator groups according to the internal power transmission section of the region power grid when the potential amplitude is smaller than the preset threshold value;
the rotating speed and power angle calculating unit is used for performing inertia center equivalence on the two clusters and respectively calculating the rotating speed and the power angle of the leading generator cluster and the lagging generator cluster;
and the static stability limit lifting unit is used for reducing the unit output of the leading generator group, correspondingly increasing the unit output of the lagging generator group, and reducing the power angle difference of the two generator groups, so that the integral equivalent Thevenin potential amplitude of the regional power grid is increased, and the static stability limit of the regional interconnected power grid tie line is improved.
Preferably, wherein at the thevenin equivalent potential determining unit, thevenin equivalent potential is determined using the following formula:
wherein the content of the first and second substances,
is the thevenin equivalent potential of the external equivalent system at the moment k; zkIs the impedance of the same value as the impedance,
in order to be the bus voltage,
is the current injected into the bus.
Preferably, in the rotation speed and power angle calculation unit, the rotation speed and power angle of the leading generator group are calculated by using the following formulas:
wherein, ω issTo advance the speed of the generator group, deltasTo advance the power angle, omega, of the generator groupiIn order to advance the rotational speed of the ith generator set in the generator set,δithe power angle of the ith generator set in the advanced generator group is set, and S is the total number of the generator sets in the advanced generator group; mSTo advance the inertia time constant of the generator group, and
Mithe inertia time constant of the ith generating set in the leading generating set group.
Preferably, in the rotation speed and power angle calculation unit, the rotation speed and power angle of the lag generator group are calculated by using the following formulas:
wherein, ω isATo retard the speed of rotation, delta, of the generator groupAFor retarding the power angle, omega, of the generator groupjFor retarding the speed, delta, of the jth generator set in the generator groupjThe power angle of the jth generator set in the lag generator group is A, and the total number of the generator sets in the lag generator group is A; mAIs a lag of the inertia time constant of the generator group, and
Mjis the inertia time constant of the jth generating set in the lag generating set.
The invention provides a method and a system for improving the static stability limit of a tie line of a large-area interconnected power grid, and aims to provide reference for arranging an operation mode for power grid operation personnel, improve the static stability limit of the large-area interconnected power grid and guarantee the safe and stable operation of the large-area interconnected power grid. The invention researches the influence factor of the static stability limit of the interconnection line of the large-area interconnected network, indicates that the static stability limit of the interconnection line of the interconnected system is influenced by the output of different clusters in the regional power network, and does not have a definite value but fluctuates in a certain range; the power angle position relation of the cluster in the regional power grid directly influences the equivalent potential amplitude of the regional power grid, and further influences the static stability limit of the connecting line. The invention achieves the purpose of improving the static stability limit of the interconnection network tie line by changing the output of different machine groups in the regional power grid by utilizing the change of the system operation mode, ensures the safe and stable operation of the interconnection network tie line, solves the problems of how to improve the static stability margin of the large-area interconnection network tie line and improve the static stability limit in the actual operation of the power grid, and improves the power transmission capacity of the interconnection network tie line.
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A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
fig. 1 is a flow chart of a method 100 for raising a static stability limit of a large area interconnected network tie line according to an embodiment of the present invention;
FIG. 2 is a three-machine model of a target interconnected power system according to an embodiment of the invention;
FIG. 3 is a region A iso-model according to an embodiment of the present invention;
FIG. 4 is a power characteristic curve when the equivalent potential amplitude is reduced according to an embodiment of the present invention;
FIG. 5 is a power characteristic curve when the magnitude of the equivalent potential becomes larger according to the embodiment of the present invention;
FIG. 6 is a block diagram of a grid architecture of a system according to an embodiment of the present invention;
FIG. 7A is an equivalent power angle curve for each cluster after increasing the output of the cluster 2 according to the embodiment of the present invention;
FIG. 7B is a graph of equivalent power angle difference between the cluster 1 and the cluster 2 after increasing the cluster 2 output according to the embodiment of the present invention;
fig. 7C is a power curve of the interconnected grid system tie-line after increasing the fleet 2 output, according to an embodiment of the present invention;
FIG. 8A is an equivalent power angle curve for each cluster after increasing the output of the cluster 1 according to the embodiment of the present invention;
fig. 8B is an equivalent power angle difference curve of the cluster 1 and the cluster 2 after increasing the output of the cluster 1 according to the embodiment of the present invention;
fig. 8C is a power curve of the interconnected grid system tie-line after increasing the cluster 1 output, according to an embodiment of the present invention; and
fig. 9 is a schematic structural diagram of a system 900 for raising the static stability limit of a large area interconnected network tie line according to an embodiment of the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Fig. 1 is a flow chart of a method 100 for raising a static stability limit of a large area interconnected network tie line according to an embodiment of the present invention. As shown in fig. 1, the method for improving the static stability limit of the tie line of the large-area interconnected power grid according to the embodiment of the present invention is to provide a reference for the power grid operator to arrange the operation mode, improve the static stability limit of the large-area interconnected power grid, and ensure the safe and stable operation of the large-area interconnected power grid. The implementation mode of the invention achieves the purpose of improving the static stability limit of the interconnection network by changing the output of different clusters in the regional power grid by using the change of the system operation mode, ensures the safe and stable operation of the interconnection network, solves the problems of how to improve the static stability margin of the large-region interconnection network in the actual operation of the power grid and improve the static stability limit, and improves the power transmission capacity of the interconnection network. The method 100 for improving the static stability limit of the large-area interconnected network connecting line provided by the embodiment of the invention starts from step 101, and in step 101, the large-area interconnected network is equalized into a two-machine model by using a Thevenin equivalent method, and the Thevenin equivalent potential of a transmitting-end power grid and the Thevenin equivalent potential of a receiving-end power grid are respectively determined.
Preferably, wherein the thevenin equivalent potential is determined using the formula:
wherein the content of the first and second substances,
is the thevenin equivalent potential of the external equivalent system at the moment k; zkIs the impedance of the same value as the impedance,
in order to be the bus voltage,
is the current injected into the bus.
For an actual power grid, if a power transmission section also exists in a regional power grid and a plurality of closely-connected clusters exist, the spatial position relation of the power angles of the clusters directly influences the static stability limit of a connecting line. In the implementation mode of the invention, a Thevenin equivalence method is utilized to equate a large-area interconnected power grid into two machine models, and two generators are respectively equated on two sides of a connecting line. Thevenin equivalent can effectively reflect the running state of the system and simplify the complex system. And for any time k, when one end of a large-area interconnected network connecting line is seen from the system, the system can be equivalent into a Thevenin equivalent two-node system in which a voltage source supplies power to the bus under study through an impedance. The equation for determining thevenin equivalent potential by the equivalent system is as follows:
wherein the content of the first and second substances,
thevenin et al for an external equivalence system at time kA value potential; zkIs the impedance of the same value as the impedance,
in order to be the bus voltage,
is the current injected into the bus; pkAnd QkRespectively the active power and the reactive power of the bus. The obtained Thevenin equivalent potential of the sending end power grid is
Thevenin equivalent potential of a receiving end power grid is
Preferably, in step 102, a potential amplitude is determined according to the thevenin equivalent potential of the transmitting-end power grid and the thevenin equivalent potential of the receiving-end power grid, the potential amplitude is compared with a preset threshold, and when the potential amplitude is smaller than the preset threshold, the power grid of the region is divided into two generator groups according to the internal transmission section of the region power grid.
Preferably, inertia center equivalence is performed on the two clusters in step 103, and the rotational speeds and power angles of the leading and lagging clusters are calculated, respectively.
Preferably wherein the speed and power angle of the lead generator group are calculated using the following equations:
wherein, ω issTo advance the speed of the generator group, deltasTo advance the power angle, omega, of the generator groupiTo advance the speed, delta, of the i-th generator set in the generator groupiThe power angle of the ith generator set in the advanced generator group is set, and S is the total number of the generator sets in the advanced generator group; mSTo advance the inertia time constant of the generator group, and
Mithe inertia time constant of the ith generating set in the leading generating set group.
Preferably, the rotation speed and the power angle of the lag generator group are calculated using the following equations:
wherein, ω isATo retard the speed of rotation, delta, of the generator groupAFor retarding the power angle, omega, of the generator groupjFor retarding the speed, delta, of the jth generator set in the generator groupjThe power angle of the jth generator set in the lag generator group is A, and the total number of the generator sets in the lag generator group is A; mAIs a lag of the inertia time constant of the generator group, and
Mjis the inertia time constant of the jth generating set in the lag generating set.
Preferably, in step 104, the unit output of the leading generator group is reduced, and the unit output of the lagging generator group is correspondingly increased, so that the power angle difference between the two generator groups is reduced, and the overall equivalent thevenin potential amplitude of the regional power grid is increased, thereby improving the static stability limit of the regional interconnected power grid tie line.
In the implementation mode of the invention, the output of the leading cluster machine set is reduced, the output of the lagging cluster machine set is correspondingly increased, so that the power angle difference delta of the two clusters is reduced, the power angle difference of the clusters in the regional power grid is reduced, the integral equivalent Thevenin potential amplitude of the regional power grid is increased, and the aim of improving the static stability limit of the interconnection line of the large-area interconnected power grid is fulfilled. Wherein Δ δ is ═ δ1-δ2|。
Fig. 2 is a three-machine model of a target interconnected power system according to an embodiment of the invention. In the interconnected power system shown in fig. 2, a regional power grid a is a transmitting-end system, and a regional power grid B is a receiving-end system.
(1) Regional power grid A internal cluster 1 transmits power to cluster 2
Assume that the system cluster 1 and the cluster 2 shown in fig. 2 both supply power to the tie-line, and the power angle of the remote cluster 1 is ahead of that of the cluster 2, i.e. the power supply direction of the internal cross section is from 1 to 2. FIG. 3 is a region A equivalent model according to an embodiment of the present invention. Thevenin equivalence is performed on the regional power grid A as shown in FIG. 3. Then, the output of the machine group 1 is increased, and the output of the machine group in the area B is reduced, so that the power of the interconnection line of the interconnection system is gradually increased and slowly reaches the static stability limit. The transmission power between the cluster 1 and the cluster 2 in the area a increases, and the power angle difference δ 12 increases. As δ 12 becomes progressively larger, the equivalent potential amplitude of the two clusters decreases, causing the power characteristic curve of the interconnected system to decrease, as shown by the curve indicated by the arrow in fig. 4 (which is merely a schematic illustration). It can be seen that the variation of the power characteristic curve directly affects the interconnection system tie quiescent limit.
And when the output of the machine group 2 is increased and the output of the machine group in the area B is reduced, the power of the interconnection line of the interconnection system is gradually increased and slowly reaches the static stability limit. The transmission power between the cluster 1 and the cluster 2 within the area a is unchanged, but as the power angles of the clusters 1 and 2 are increased relative to the other area grid, the delta 12 is reduced to a small extent, and the reduction is related to the variation of the delta 1. The equivalent potential amplitudes of the two clusters are increased, the power characteristic of the interconnected system is improved, and a power characteristic curve is shown in fig. 5 when the equivalent potential amplitude is increased. It can be seen that the quiet limit of the interconnection system tie is greater than that of the former case.
(2) Regional power grid A internal cluster 2 transmits power to cluster 1
It is assumed that the cluster 2 within the area a shown in fig. 2 has a power angle leading the cluster 2, i.e., the power feeding direction of the internal cross-section is from 2 to 1. And when the output of the machine group 1 is increased and the output of the machine group in the area B is reduced, the power of the interconnection line of the interconnection system is gradually increased and slowly reaches the static stability limit. The transmission power between the cluster 1 and the cluster 2 in the area a is reduced, and the power angle difference δ 21 is reduced. As δ 21 is progressively reduced, the equivalent potential amplitude of the two clusters increases, causing the power characteristic curve of the interconnected system to rise, similar to the effect shown by the curve indicated by the arrow in fig. 5.
And when the output of the machine group 2 is increased and the output of the machine group in the area B is reduced, the power of the interconnection line of the interconnection system is gradually increased and slowly reaches the static stability limit. The transmission power between the cluster 1 and the cluster 2 within the area a is unchanged, but as the power angles of the clusters 1 and 2 increase relative to the other area grid, δ 21 increases, with the magnitude of the increase being related to the amount of change in δ 1. The magnitude of the equivalent potential of the two clusters is reduced, lowering the power characteristic curve of the interconnected system, similar to that shown in fig. 4.
The quiescent stability limit of the tie line of the large-area interconnection system is not a fixed value, and is influenced by the operation mode and the selection of switching units on two sides, and usually, the power transmission capacity of the tie line can only be described to a certain extent by a calculated value of engineering analysis.
Fig. 6 is a block diagram of a grid of a system according to an embodiment of the present invention. As shown in fig. 6, the lines 17-18 and the lines 15-16 form a transmission profile of the interconnected network, with the left side being the zone B and the right side zone a comprising the fleet 1 and the fleet 2. The area A comprises 2 clusters, namely a cluster 1 and a cluster 2. Fleet 2 delivers 459MW and fleet 1 delivers 270.4MW over lines 27-17 and is at the grid end on the electrical connection, away from the interconnect system connection. Zone a delivers power to zone B via power delivery links 17-18 and 15-16, with an initial power of 697.2 MW.
The effect of changing the contribution of different fleet forces on the quiet stability limit of the interconnect system link is studied below.
Firstly, the output of the machine set of the machine group 2 is increased, and the output of the machine set of the area B is reduced at the same time, so that the power of the connecting line is gradually increased to reach the static stability limit. As can be seen from fig. 7A and 7B, as the output of the fleet 2 gradually increases, the power angle difference with the fleet 1 gradually decreases, and the calculated tie-line quietness limit is 941MW, as shown in fig. 7C.
And secondly, increasing the output of the machine set of the machine group 1, and simultaneously reducing the output of the machine set in the area B, so that the power of the connecting line is gradually increased to reach the static stability limit. As can be seen from fig. 8A and 8B, as the fleet 1 output increases, its power angle difference with the fleet 2 increases, decreasing to 764MW as compared to the previously calculated tie-line quietness limit, as shown in fig. 8C. This is because the power angle difference between the two groups gradually increases and simultaneously reduces the equivalent potential amplitude of the region a, which causes the power characteristic curve to decrease, and therefore the static stability limit decreases accordingly.
Fig. 9 is a schematic structural diagram of a system 900 for raising the static stability limit of a large area interconnected network tie line according to an embodiment of the present invention. As shown in fig. 9, the system 900 for increasing the static stability limit of the large area interconnected network tie line according to the embodiment of the present invention includes: thevenin isopotential determination unit 901, generator group division unit 902, rotation speed and power angle calculation unit 903, and static stability limit elevation unit 904. Preferably, in the thevenin equivalent potential determination unit 901, the large-area interconnected power grid is equivalent into a two-machine model by using a thevenin equivalent method, and the thevenin equivalent potential of the transmitting-end power grid and the thevenin equivalent potential of the receiving-end power grid are respectively determined.
Preferably, wherein at the thevenin equivalent potential determining unit, thevenin equivalent potential is determined using the following formula:
wherein the content of the first and second substances,
is the thevenin equivalent potential of the external equivalent system at the moment k; zkIs the impedance of the same value as the impedance,
in order to be the bus voltage,
is the current injected into the bus.
Preferably, in the generator group dividing unit 902, a potential amplitude is determined according to the thevenin equivalent potential of the transmitting-end power grid and the thevenin equivalent potential of the receiving-end power grid, the potential amplitude is compared with a preset threshold, and when the potential amplitude is smaller than the preset threshold, the power grid in the area is divided into two generator groups according to the internal transmission section of the area power grid.
Preferably, in the rotation speed and power angle calculation unit 903, inertia center equivalence is performed on the two clusters, and the rotation speed and power angle of the leading cluster and the lagging cluster are calculated respectively.
Preferably, in the rotation speed and power angle calculation unit, the rotation speed and power angle of the leading generator group are calculated by using the following formulas:
wherein, ω issTo advance the speed of the generator group, deltasTo advance the power angle, omega, of the generator groupiTo advance the speed, delta, of the i-th generator set in the generator groupiThe power angle of the ith generator set in the advanced generator group is set, and S is the total number of the generator sets in the advanced generator group; mSTo advance the inertia time constant of the generator group, and
Mithe inertia time constant of the ith generating set in the leading generating set group.
Preferably, in the rotation speed and power angle calculation unit, the rotation speed and power angle of the lag generator group are calculated by using the following formulas:
wherein, ω isATo retard the speed of rotation, delta, of the generator groupAFor retarding the power angle, omega, of the generator groupjFor retarding the speed, delta, of the jth generator set in the generator groupjThe power angle of the jth generator set in the lag generator group is A, and the total number of the generator sets in the lag generator group is A; mAIs a lag of the inertia time constant of the generator group, and
Mjis the inertia time constant of the jth generating set in the lag generating set.
Preferably, in the static stability limit raising unit 904, the unit output of the leading generator group is reduced, and the unit output of the lagging generator group is correspondingly increased, so as to reduce the power angle difference between the two generator groups, so that the overall equivalent thevenin potential amplitude of the regional power grid is increased, and the static stability limit of the regional interconnected power grid tie line is raised.
The system 900 for increasing the static stability limit of the large area interconnected network tie line according to the embodiment of the present invention corresponds to the method 100 for increasing the static stability limit of the large area interconnected network tie line according to another embodiment of the present invention, and is not described herein again.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
Claims (8)
1. A method of raising the limit of static stability of a large area interconnected network tie, the method comprising:
equating the large-area interconnected power grid into a two-machine model by using a Thevenin equivalent method, and respectively determining the Thevenin equivalent potential of a transmitting-end power grid and the Thevenin equivalent potential of a receiving-end power grid;
determining a potential amplitude according to the Thevenin equivalent potential of the transmitting-end power grid and the Thevenin equivalent potential of the receiving-end power grid, comparing the potential amplitude with a preset threshold, and dividing the power grid of the region into two generator groups according to the internal transmission section of the region power grid when the potential amplitude is smaller than the preset threshold;
performing inertia center equivalence on the two clusters, and respectively calculating the rotating speed and the power angle of the leading generator cluster and the lagging generator cluster;
the unit output of the leading generator group is reduced, the unit output of the lagging generator group is correspondingly increased, and the power angle difference of the two generator groups is reduced, so that the integral equivalent Thevenin potential amplitude of the regional power grid is increased, and the static stability limit of the regional interconnected power grid tie line is improved.
2. The method according to claim 1, wherein the thevenin equivalent potential is determined using the formula:
wherein the content of the first and second substances,
is the thevenin equivalent potential of the external equivalent system at the moment k; zkIs the impedance of the same value as the impedance,
in order to be the bus voltage,
is the current injected into the bus.
3. The method of claim 1, wherein the speed and power angle of the lead generator group are calculated using the following equations:
wherein, ω issTo advance the speed of the generator group, deltasTo advance the power angle, omega, of the generator groupiFor leading generator groupRotational speed, delta, of the ith generator setiThe power angle of the ith generator set in the advanced generator group is set, and S is the total number of the generator sets in the advanced generator group; mSTo advance the inertia time constant of the generator group, and
Mithe inertia time constant of the ith generating set in the leading generating set group.
4. The method of claim 1, wherein the speed and power angle of the lag generator group are calculated using the following equations:
wherein, ω isATo retard the speed of rotation, delta, of the generator groupAFor retarding the power angle, omega, of the generator groupjFor retarding the speed, delta, of the jth generator set in the generator groupjThe power angle of the jth generator set in the lag generator group is A, and the total number of the generator sets in the lag generator group is A; mAIs a lag of the inertia time constant of the generator group, and
Mjis the inertia time constant of the jth generating set in the lag generating set.
5. A system for improving the static stability limit of a large area interconnected network tie, the system comprising:
the Thevenin equivalent potential determining unit is used for equating the large-area interconnected power grid into a two-machine model by utilizing a Thevenin equivalent method and respectively determining the Thevenin equivalent potential of a transmitting-end power grid and the Thevenin equivalent potential of a receiving-end power grid;
the generator group division unit is used for determining a potential amplitude according to the Thevenin equivalent potential of the transmitting-end power grid and the Thevenin equivalent potential of the receiving-end power grid, comparing the potential amplitude with a preset threshold value, and dividing the power grid of the region into two generator groups according to the internal power transmission section of the region power grid when the potential amplitude is smaller than the preset threshold value;
the rotating speed and power angle calculating unit is used for performing inertia center equivalence on the two clusters and respectively calculating the rotating speed and the power angle of the leading generator cluster and the lagging generator cluster;
and the static stability limit lifting unit is used for reducing the unit output of the leading generator group, correspondingly increasing the unit output of the lagging generator group, and reducing the power angle difference of the two generator groups, so that the integral equivalent Thevenin potential amplitude of the regional power grid is increased, and the static stability limit of the regional interconnected power grid tie line is improved.
6. The system according to claim 5, characterized in that at the thevenin equipotential determining unit, the thevenin equipotential is determined using the formula:
wherein the content of the first and second substances,
is the thevenin equivalent potential of the external equivalent system at the moment k; zkIs the impedance of the same value as the impedance,
in order to be the bus voltage,
is the current injected into the bus.
7. The system of claim 5, wherein the speed and power angle calculation unit calculates the speed and power angle of the lead generator group using the following equations:
wherein, ω issTo advance the speed of the generator group, deltasTo advance the power angle, omega, of the generator groupiTo advance the speed, delta, of the i-th generator set in the generator groupiThe power angle of the ith generator set in the advanced generator group is set, and S is the total number of the generator sets in the advanced generator group; mSTo advance the inertia time constant of the generator group, and
Mithe inertia time constant of the ith generating set in the leading generating set group.
8. The system of claim 5, wherein the speed and power angle calculation unit calculates the speed and power angle of the lag generator group using the following equations:
wherein, ω isATo retard the speed of rotation, delta, of the generator groupAFor retarding the power angle, omega, of the generator groupjFor retarding the speed, delta, of the jth generator set in the generator groupjThe power angle of the jth generator set in the lag generator group is A, and the total number of the generator sets in the lag generator group is A; mAIs a lag of the inertia time constant of the generator group, and
Mjis the inertia time constant of the jth generating set in the lag generating set.
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| CN109799456B (en) * | 2019-02-28 | 2022-12-13 | 中国电力科学研究院有限公司 | Method and system for determining transient power angle stability of single-machine infinite system |
| CN110514953B (en) * | 2019-03-25 | 2021-11-05 | 中国电力科学研究院有限公司 | Power angle and voltage aliasing-based power grid fault simulation identification method and system |
| CN110601176B (en) * | 2019-08-01 | 2022-04-15 | 中国电力科学研究院有限公司 | Method and system for improving static stability limit of power grid tie line and early warning |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101363885A (en) * | 2008-09-10 | 2009-02-11 | 中国电力科学研究院 | Method for discriminating voltage instability and load angle instability based on thevenin equivalent |
| CN102684187A (en) * | 2012-04-24 | 2012-09-19 | 南京南瑞集团公司 | Power grid static stability analysis method on basis of WAMS and online simulation data |
| CN107732899A (en) * | 2017-09-22 | 2018-02-23 | 中国电力科学研究院 | The optimization method and device of communication channel ability to transmit electricity in AC-DC hybrid power grid |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US9291655B2 (en) * | 2013-05-20 | 2016-03-22 | Quanta Technology, Llc | Monitoring voltage stability of a transmission corridor |
| CN106682407B (en) * | 2016-12-19 | 2019-05-31 | 国网上海市电力公司 | Voltage stability assessment method based on Thevenin's equivalence and branch transmission power limit |
-
2018
- 2018-06-19 CN CN201810628714.5A patent/CN108847692B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101363885A (en) * | 2008-09-10 | 2009-02-11 | 中国电力科学研究院 | Method for discriminating voltage instability and load angle instability based on thevenin equivalent |
| CN102684187A (en) * | 2012-04-24 | 2012-09-19 | 南京南瑞集团公司 | Power grid static stability analysis method on basis of WAMS and online simulation data |
| CN107732899A (en) * | 2017-09-22 | 2018-02-23 | 中国电力科学研究院 | The optimization method and device of communication channel ability to transmit electricity in AC-DC hybrid power grid |
Non-Patent Citations (2)
| Title |
|---|
| 区域电网内弱联机群摆动对互联系统功角稳定性的影响;顾卓远 等;《中国电机工程学报》;20150320;第35卷(第6期);全文 * |
| 基于响应的电力系统暂态稳定控制技术研究;顾卓远;《中国博士学位论文全文数据库工程科技Ⅱ辑》;20141115(第11期);第81-94页 * |
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