CN114243711A - Large-scale power grid voltage sag evaluation method based on change branch influence domain - Google Patents

Large-scale power grid voltage sag evaluation method based on change branch influence domain Download PDF

Info

Publication number
CN114243711A
CN114243711A CN202111588779.XA CN202111588779A CN114243711A CN 114243711 A CN114243711 A CN 114243711A CN 202111588779 A CN202111588779 A CN 202111588779A CN 114243711 A CN114243711 A CN 114243711A
Authority
CN
China
Prior art keywords
power grid
node
voltage
evaluated
sag
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202111588779.XA
Other languages
Chinese (zh)
Other versions
CN114243711B (en
Inventor
张逸
章书旗
黄佳铭
贾荣
吴逸帆
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fuzhou University
Original Assignee
Fuzhou University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fuzhou University filed Critical Fuzhou University
Priority to CN202111588779.XA priority Critical patent/CN114243711B/en
Publication of CN114243711A publication Critical patent/CN114243711A/en
Application granted granted Critical
Publication of CN114243711B publication Critical patent/CN114243711B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation

Abstract

The invention relates to a large-scale power grid voltage sag evaluation method based on a variable branch influence domain, which comprises the following steps of: the method comprises the following steps of S1, determining a regional power grid range W to be evaluated as a whole grid, S2, carrying out whole grid load flow calculation and generating a load flow calculation result file, S3, setting line fault positions, fault types and fault duration time in the regional power grid range W to be evaluated, S4, calculating sag expected values and outputting risk severity grades of all buses; and S5, judging whether the power grid topological structure is changed, and when the power grid topological structure is changed, performing load flow calculation on the changed whole power grid again, wherein the load flow calculation step S6 is to keep the severity grade of each bus voltage sag risk outside the power grid range W of the area to be evaluated unchanged, and arrange the severity grade of each bus voltage sag risk inside and outside the power grid range of the area to be evaluated to obtain the severity grade of each bus voltage sag risk in the whole power grid range.

Description

Large-scale power grid voltage sag evaluation method based on change branch influence domain
Technical Field
The invention relates to the field of voltage sag assessment, in particular to a large-scale power grid voltage sag assessment method based on a variable branch influence domain.
Background
In current power systems, the problem of voltage sag in terms of power quality is increasingly highlighted. Since voltage sag causes a great amount of economic loss for high-tech enterprises and industrial users, the requirement of modern loads on the quality of electric energy is more and more strict. Under the background, the method has important significance for the evaluation and treatment research of the voltage sag. In practice, the voltage sag monitoring device cannot be installed in a large number in the whole network, the monitored data cannot cover the whole network, and the severity of the voltage sag risk of the whole network is difficult to be comprehensively evaluated.
Disclosure of Invention
In view of this, the present invention provides a large-scale grid voltage sag evaluation method based on a variable branch influence domain, so as to realize efficient evaluation of large-scale grid voltage sag.
In order to achieve the purpose, the invention adopts the following technical scheme:
a large-scale power grid voltage sag assessment method based on a variable branch influence domain comprises the following steps:
step S1, determining the regional power grid range W to be evaluated as a whole grid;
step S2, carrying out load flow calculation of the whole network and generating a load flow calculation result file;
step S3, setting the line fault position, the fault type and the fault duration within the power grid range W of the area to be evaluated;
step S4, calculating the voltage sag amplitudes of each bus under different conditions, calculating sag expected values and outputting the risk severity grade of each bus by using the obtained voltage sag amplitudes;
step S5, judging whether the power grid topological structure changes, when the power grid topological structure changes, carrying out load flow calculation on the changed whole power grid again to generate a new load flow result file, carrying out steps S3 and S4 in the newly determined area power grid range to be evaluated, calculating and analyzing to obtain sag expected values of all buses in the area and outputting a voltage sag risk severity grade;
and step S6, keeping the severity grade of each bus voltage sag risk outside the power grid range W of the area to be evaluated unchanged. And sorting the bus voltage sag risk severity grades inside and outside the power grid range of the area to be evaluated to obtain the bus voltage sag risk severity grades in the whole power grid range.
Further, the step S1 is specifically:
defining the regional power grid range W to be evaluated as the whole grid, i.e.
W＝[a1,a2···an] (1)
Wherein W is the regional power grid range to be evaluated of the voltage sag, aiIs the name of the node; n is the number of nodes in the whole network.
Further, the step S3 is specifically: respectively setting single-phase short-circuit faults, two-phase grounding short-circuit faults, interphase short-circuit faults and three-phase short-circuit faults at 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of each line in the power grid range W of the area to be evaluated; the fault duration is set according to different voltage grades of the line, and the line with the voltage grade of 220kV is set to be 120 ms; setting a line with a voltage level of 110kV to be 300 ms; setting the line with the voltage level of 35kV as 700 ms; the line with a voltage level of 10kV was set to 0.5 s.
Further, the calculating of the sag expectation value and the outputting of the risk severity level of each bus are as follows:
1) calculating the sag expected value of each bus, wherein the formula is as follows:
Figure BDA0003429049050000031
in the formula: e (i) is the sag expected value of the i bus; n is the total simulation times; u shapeijThe minimum residual voltage amplitude of the i bus is obtained in the j simulation;
2) arranging the buses from small to large according to the sag expected values of the buses;
3) the first 20% of the buses are taken as a severe grade, 20% -40% are taken as a medium grade, 40% -60% are taken as a slight grade, and 60% -100% are taken as a good grade.
Furthermore, the change of the power grid topological structure considers the connection or disconnection of a line, a main transformer and a bus, and the electrical distance between the change node and other nodes of the power grid needs to be calculated; the change of the power grid topological structure is divided into two conditions of disconnection of an old branch and connection of a new branch: when an old branch is disconnected, selecting a node of the old branch still connected with the large power grid as a change node; and when a new branch is accessed, selecting a new access large power grid node as a change node.
Further, the electrical distance represents a coupling relationship between two nodes, and the electrical distance is represented by sensitivity, which is selected as follows:
the polar coordinate form of the Newton Raphson method power flow equation of the N-node system is as follows:
Figure BDA0003429049050000032
wherein, Pi、QiRespectively injecting active power and reactive power into the node i; viIs the voltage amplitude of node i; thetaijIs the phase angle difference between the voltage vectors of the node i and the node j; gij、BijAre respectively node admittance matrix elements YijThe real part and the imaginary part of (c); j belongs to i and represents that the node j is directly connected with the node i;
the above formula is converted to obtain:
Figure BDA0003429049050000041
wherein, Δ Pi、ΔQiInjecting unbalance amounts of active power and reactive power into the node i respectively; pGi、QGiInjecting active power and reactive power for a power supply at a node i; pLi、QLiActive power and reactive power consumed by the load at the node i;
based on the Taylor principle, the above formula is linearized to obtain a conventional trend equation as follows:
Figure BDA0003429049050000042
wherein, the delta P and the delta Q are unbalance matrixes of node injection active power and node injection reactive power respectively; H. n, K, L are the four plates of the Jacobian matrix respectively; Δ θ, Δ V are the increments of the node voltage phase angle and voltage amplitude, respectively;
the relation between active power, reactive power, voltage and phase angle is considered, and the relation is obtained as follows:
Figure BDA0003429049050000043
wherein the content of the first and second substances,
Figure BDA0003429049050000044
sensitivity to reactive injection for voltage amplitude.
Further, the newly determined area power grid range to be evaluated is obtained based on a threshold value α, and specifically includes:
from a in the original to-be-evaluated regional power grid range W1,a2···anAnd screening the node to obtain the changed branch influence domain, namely the new regional power grid range to be evaluated:
W＝[a’1,a’2···a’m] (7)
wherein, a'iThe nodes are selected according to the threshold value alpha; m is the number of nodes contained in the change leg influence domain.
Compared with the prior art, the invention has the following beneficial effects:
1. in the invention, on the premise of ensuring the accuracy of voltage sag evaluation for a large-scale power grid with quick change, a reasonable change node influence domain is selected, and the power grid range W of a region to be evaluated is reduced;
2. the method greatly improves the high efficiency of voltage sag evaluation and strengthens the utilization of the existing historical data.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a system diagram of an IEEE30 node in accordance with an embodiment of the present invention;
fig. 3 is a system diagram of access of a node 31 in an embodiment of the present invention;
FIG. 4 is an impact domain of branches 7-31 in an embodiment of the present invention;
FIG. 5 is a diagram of an 18-19 disconnect system in accordance with an embodiment of the present invention;
FIG. 6 is an exemplary embodiment of the impact domain of the change branches 18-19.
Detailed Description
The invention is further explained below with reference to the drawings and the embodiments.
Referring to fig. 1, the present invention provides a large-scale grid voltage sag evaluation method based on a variable branch influence domain, including the following steps:
and step S1, determining the regional power grid range W to be evaluated as a whole grid, namely:
W＝[a1,a2···an] (1)
wherein W is the regional power grid range to be evaluated of the voltage sag, aiIs the name of the node; n is the number of nodes in the whole network.
Step S2, carrying out load flow calculation of the whole network and generating a load flow calculation result file;
step S3, setting the line fault position, the fault type and the fault duration within the power grid range W of the area to be evaluated;
in the present embodiment, preferably, a single-phase short-circuit fault, a two-phase ground short-circuit fault, an inter-phase short-circuit fault, and a three-phase short-circuit fault are respectively set at 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of each line of the regional power grid range W to be evaluated. The fault duration time needs to be set according to different voltage grades of the line, and the line with the voltage grade of 220kV is set to be 120 ms; setting a line with a voltage level of 110kV to be 300 ms; setting the line with the voltage level of 35kV as 700 ms; the line with a voltage level of 10kV was set to 0.5 s.
Step S4, calculating the voltage sag amplitudes of each bus under different conditions, calculating sag expected values and outputting the risk severity grade of each bus by using the obtained voltage sag amplitudes;
preferably, the risk severity level is calculated as follows:
1) calculating the sag expected value of each bus, wherein the formula is as follows:
Figure BDA0003429049050000061
in the formula: e (i) is the sag expected value of the i bus; n is the total simulation times; u shapeijThe minimum residual voltage amplitude of the i bus is obtained in the j simulation;
2) arranging the buses from small to large according to the sag expected values of the buses;
3) the first 20% of the buses are taken as a severe grade, 20% -40% are taken as a medium grade, 40% -60% are taken as a slight grade, and 60% -100% are taken as a good grade.
Step S5, judging whether the power grid topological structure changes, when the power grid topological structure changes, carrying out load flow calculation on the changed whole power grid again to generate a new load flow result file, carrying out steps S3 and S4 in the newly determined area power grid range to be evaluated, calculating and analyzing to obtain sag expected values of all buses in the area and outputting a voltage sag risk severity grade;
the change of the power grid topological structure is divided into two conditions of disconnection of an old branch and connection of a new branch: when an old branch is disconnected, selecting a node of the old branch still connected with a large power grid as a change node (1 or 2 nodes can be selected); and when a new branch is accessed, selecting a new access large power grid node as a change node.
The electrical distance represents the coupling relationship between two nodes, but the strength of the two-point coupling is not clear. Therefore, it is necessary to express the coupling relationship between two variables respectively belonging to two nodes, and the sensitivity is a value obtained on the basis of linearizing the coupling relationship between the two variables, so that the sensitivity is selected to express the electrical distance.
The polar coordinate form of the Newton Raphson method power flow equation of the N-node system is as follows:
Figure BDA0003429049050000071
wherein, Pi、QiRespectively injecting active power and reactive power into the node i; viIs the voltage amplitude of node i; thetaijIs the phase angle difference between the voltage vectors of the node i and the node j; gij、BijAre respectively node admittance matrix elements YijThe real part and the imaginary part of (c); j e i indicates that node j and node i are directly connected.
The above formula is converted to obtain:
Figure BDA0003429049050000072
wherein, Δ Pi、ΔQiInjecting unbalance amounts of active power and reactive power into the node i respectively; pGi、QGiInjecting active power and reactive power for a power supply at a node i; pLi、QLiActive and reactive power consumed by the load at node i.
Based on the Taylor principle, the above formula is linearized to obtain a conventional trend equation as follows:
Figure BDA0003429049050000081
wherein, the delta P and the delta Q are unbalance matrixes of node injection active power and node injection reactive power respectively; H. n, K, L are the four plates of the Jacobian matrix respectively; Δ θ, Δ V are increments of the node voltage phase angle and voltage magnitude, respectively.
Considering the relationship between active and reactive power and the voltage and phase angle, the relationship can be obtained as follows:
Figure BDA0003429049050000082
wherein the content of the first and second substances,
Figure BDA0003429049050000083
sensitivity to reactive injection for voltage amplitude.
(7) In practical engineering application, the influence domain of the changed branch is screened by setting a certain threshold value alpha. The larger the sensitivity is, the smaller the electrical distance between two nodes is, and the stronger the node coupling relation is. Thus for nodes with a sensitivity less than or equal to the threshold α, i.e.
Figure BDA0003429049050000085
The influence of the change of the power grid topological structure on the branch voltage sag evaluation can be considered to be negligible; for nodes with sensitivity greater than the threshold α
Figure BDA0003429049050000084
The voltage sag evaluation result of the node can be considered to be influenced by the change of the topological structure of the power grid, so that the node a is connectediClassified as a change leg impact domain. By the method, a in the original to-be-evaluated regional power grid range W can be selected1,a2···anAnd screening the node to obtain the changed branch influence domain, namely the new regional power grid range to be evaluated:
W＝[a’1,a’2···a’m] (7)
wherein, a'iThe nodes are selected according to the threshold value alpha; m is the number of nodes contained in the change leg influence domain. At this time, a new one is to be evaluatedThe regional grid extent W will be greatly reduced compared to the full grid.
And step S6, keeping the severity grade of each bus voltage sag risk outside the power grid range W of the area to be evaluated unchanged. And sorting the bus voltage sag risk severity grades inside and outside the power grid range of the area to be evaluated to obtain the bus voltage sag risk severity grades in the whole power grid range.
Example 1:
in this embodiment, as shown in fig. 2, the IEEE30 node system model includes 6 infinite power supplies and 6 transformers.
(1) Determining that the area range of the power grid to be evaluated is a 30-node system, namely:
W＝[1,2···30]
(2) and carrying out load flow calculation of the whole network and generating a load flow calculation result file.
(3) And setting the line fault position, the fault type and the fault duration time within the range of the power grid area to be evaluated, and performing simulation.
(4) And obtaining the voltage sag amplitudes of the buses under different conditions through the calculation process. Using the obtained voltage sag amplitude value according to the formula
Figure BDA0003429049050000091
And calculating the sag expected value. And sequencing the sag expected values of all nodes in the regional power grid range W to be evaluated to obtain the risk severity level corresponding to each node.
(5) The change of the power grid topological structure is divided into two conditions of disconnection of an old branch and connection of a new branch:
1) access of new tributaries
When a new node 31 accesses the IEEE30 node system, as shown in fig. 3, the grid topology changes. Determining the branch circuits 7-31 as changed branch circuits and the node 31 as a changed node, and performing load flow calculation analysis on the whole network again. The sensitivity between each node and the change node 31 is calculated according to equations (3) to (6).
And screening out the influence domain of the change branch 7-31 through a set transfer coefficient threshold value alpha, and taking the influence domain as a new regional power grid range W to be evaluated. Suppose that the influence domains of the screened change branches 7-31, as shown in fig. 4, include nodes: 2,4,5,6,7,8,9,28, 31. The regional grid area to be evaluated is W ═ 2,4,5,6,7,8,9,28, 31.
2) Disconnection of old branch
When the transformers on the branches 18-19 are shut down, the branches 18-19 are disconnected, as shown in fig. 5, and the grid topology changes. And determining the branch 18-19 as a changed branch, and performing load flow calculation analysis on the whole network again, wherein the 18 node and the 19 node are changed nodes. According to equations (3) to (6), the sensitivity between each node and the change node 18 and the change node 19 is calculated.
And screening out the influence domain of the change branches 18-19 through a set transfer coefficient threshold value alpha, and taking the influence domain as a new regional power grid range W to be evaluated. Suppose that the influence domains of the screened change branches 18-19, as shown in fig. 6, contain nodes: 10,12,14,15,18,19,20,21,22,23, 24. The regional grid area W to be evaluated is W ═ 10,12,14,15,18,19,20,21,22,23, 24.
(6) And (5) repeating the steps (3) and (4) to obtain a new node voltage sag risk severity grade within the regional power grid range W to be evaluated.
(7) And keeping the severity grade of each bus voltage sag risk outside the power grid range W of the area to be evaluated unchanged. And sorting the bus voltage sag risk severity grades inside and outside the power grid range of the area to be evaluated to obtain the bus voltage sag risk severity grades in the whole power grid range.
The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

Claims (7)

1. A large-scale power grid voltage sag assessment method based on a variable branch influence domain is characterized by comprising the following steps:
step S1, determining the regional power grid range W to be evaluated as a whole grid;
step S2, carrying out load flow calculation of the whole network and generating a load flow calculation result file;
step S3, setting the line fault position, the fault type and the fault duration within the power grid range W of the area to be evaluated;
step S4, calculating the voltage sag amplitudes of each bus under different conditions, calculating sag expected values and outputting the risk severity grade of each bus by using the obtained voltage sag amplitudes;
step S5, judging whether the power grid topological structure changes, when the power grid topological structure changes, carrying out load flow calculation on the changed whole power grid again to generate a new load flow result file, carrying out steps S3 and S4 in the newly determined area power grid range to be evaluated, calculating and analyzing to obtain sag expected values of all buses in the area and outputting a voltage sag risk severity grade;
and S6, keeping the severity grade of each bus voltage sag risk outside the power grid range W of the area to be evaluated unchanged, and sorting the severity grade of each bus voltage sag risk inside and outside the power grid range of the area to be evaluated to obtain the severity grade of each bus voltage sag risk within the whole power grid range.
2. The large-scale grid voltage sag evaluation method based on the changed branch influence domain according to claim 1, wherein the step S1 specifically comprises:
defining the regional power grid range W to be evaluated as the whole grid, i.e.
W＝[a1,a2…an] (1)
Wherein W is the regional power grid range to be evaluated of the voltage sag, aiIs the name of the node; n is the number of nodes in the whole network.
3. The large-scale grid voltage sag evaluation method based on the changed branch influence domain according to claim 1, wherein the step S3 specifically comprises: respectively setting single-phase short-circuit faults, two-phase grounding short-circuit faults, interphase short-circuit faults and three-phase short-circuit faults at 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of each line in the power grid range W of the area to be evaluated; the fault duration is set according to different voltage grades of the line, and the line with the voltage grade of 220kV is set to be 120 ms; setting a line with a voltage level of 110kV to be 300 ms; setting the line with the voltage level of 35kV as 700 ms; the line with a voltage level of 10kV was set to 0.5 s.
4. The large-scale grid voltage sag evaluation method based on the changing branch influence domain according to claim 1, wherein the sag expectation value is calculated and the risk severity level of each bus is output, specifically as follows:
1) calculating the sag expected value of each bus, wherein the formula is as follows:
Figure FDA0003429049040000021
in the formula: e (i) is the sag expected value of the i bus; n is the total simulation times; u shapeijThe minimum residual voltage amplitude of the i bus is obtained in the j simulation;
2) arranging the buses from small to large according to the sag expected values of the buses;
3) the first 20% of the buses are taken as a severe grade, 20% -40% are taken as a medium grade, 40% -60% are taken as a slight grade, and 60% -100% are taken as a good grade.
5. The method for evaluating voltage sag of a large power grid based on a changing branch circuit influence domain according to claim 1, wherein the change of the power grid topology takes into account the connection or disconnection of lines, main transformers and buses, and the electrical distance between the changing node and other nodes of the power grid needs to be calculated; the change of the power grid topological structure is divided into two conditions of disconnection of an old branch and connection of a new branch: when an old branch is disconnected, selecting a node of the old branch still connected with the large power grid as a change node; and when a new branch is accessed, selecting a new access large power grid node as a change node.
6. The method according to claim 5, wherein the electrical distance represents a coupling relationship between two nodes, and the electrical distance is represented by sensitivity, and is specifically as follows:
the polar coordinate form of the Newton Raphson method power flow equation of the N-node system is as follows:
Figure FDA0003429049040000031
wherein, Pi、QiRespectively injecting active power and reactive power into the node i; viIs the voltage amplitude of node i; thetaijIs the phase angle difference between the voltage vectors of the node i and the node j; gij、BijAre respectively node admittance matrix elements YijThe real part and the imaginary part of (c); j belongs to i and represents that the node j is directly connected with the node i;
the above formula is converted to obtain:
Figure FDA0003429049040000032
wherein, Δ Pi、ΔQiInjecting unbalance amounts of active power and reactive power into the node i respectively; pGi、QGiInjecting active power and reactive power for a power supply at a node i; pLi、QLiActive power and reactive power consumed by the load at the node i;
based on the Taylor principle, the above formula is linearized to obtain a conventional trend equation as follows:
Figure FDA0003429049040000033
wherein, the delta P and the delta Q are unbalance matrixes of node injection active power and node injection reactive power respectively; H. n, K, L are the four plates of the Jacobian matrix respectively; Δ θ, Δ V are the increments of the node voltage phase angle and voltage amplitude, respectively;
the relation between active power, reactive power, voltage and phase angle is considered, and the relation is obtained as follows:
Figure FDA0003429049040000041
wherein the content of the first and second substances,
Figure FDA0003429049040000042
sensitivity to reactive injection for voltage amplitude.
7. The large-scale grid voltage sag evaluation method based on the changing branch influence domain according to claim 6, wherein the newly determined area grid range to be evaluated is obtained based on a threshold α, and specifically comprises:
from a in the original to-be-evaluated regional power grid range W1,a2…anAnd screening the node to obtain the changed branch influence domain, namely the new regional power grid range to be evaluated:
W＝[a′1,a′2…a′m] (7)
wherein, a'iThe nodes are selected according to the threshold value alpha; m is the number of nodes contained in the change leg influence domain.
CN202111588779.XA 2021-12-23 2021-12-23 Large-scale power grid voltage sag evaluation method based on change branch influence domain Active CN114243711B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111588779.XA CN114243711B (en) 2021-12-23 2021-12-23 Large-scale power grid voltage sag evaluation method based on change branch influence domain

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111588779.XA CN114243711B (en) 2021-12-23 2021-12-23 Large-scale power grid voltage sag evaluation method based on change branch influence domain

Publications (2)

Publication Number Publication Date
CN114243711A true CN114243711A (en) 2022-03-25
CN114243711B CN114243711B (en) 2022-11-08

Family

ID=80761835

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111588779.XA Active CN114243711B (en) 2021-12-23 2021-12-23 Large-scale power grid voltage sag evaluation method based on change branch influence domain

Country Status (1)

Country Link
CN (1) CN114243711B (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014173131A1 (en) * 2013-04-23 2014-10-30 国家电网公司 Large power grid overall situation on-line integrated quantitative evaluation method based on response
CN104281892A (en) * 2014-10-15 2015-01-14 国家电网公司 New construction and reconstruction planning cooperative optimization method for main equipment in power distribution network
CN105550947A (en) * 2016-02-04 2016-05-04 陆如 Power distribution network reconstruction method
CN108832606A (en) * 2018-06-21 2018-11-16 东南大学 It is a kind of meter and region measurement capability active distribution network protection scheme
CN112345853A (en) * 2020-10-30 2021-02-09 广东电网有限责任公司广州供电局 Method for evaluating improvement degree of voltage sag characteristic of transformer substation bus by fault current limiter
CN113011026A (en) * 2021-03-19 2021-06-22 福州大学 Power grid voltage sag simulation method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014173131A1 (en) * 2013-04-23 2014-10-30 国家电网公司 Large power grid overall situation on-line integrated quantitative evaluation method based on response
CN104281892A (en) * 2014-10-15 2015-01-14 国家电网公司 New construction and reconstruction planning cooperative optimization method for main equipment in power distribution network
CN105550947A (en) * 2016-02-04 2016-05-04 陆如 Power distribution network reconstruction method
CN108832606A (en) * 2018-06-21 2018-11-16 东南大学 It is a kind of meter and region measurement capability active distribution network protection scheme
CN112345853A (en) * 2020-10-30 2021-02-09 广东电网有限责任公司广州供电局 Method for evaluating improvement degree of voltage sag characteristic of transformer substation bus by fault current limiter
CN113011026A (en) * 2021-03-19 2021-06-22 福州大学 Power grid voltage sag simulation method

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
ZHANG YI,ET AL.: "The Design and Field Test of a Shunt Unified Power Quality Controller for Mitigating Voltage Sags", 《2020 IEEE 3RD STUDENT CONFERENCE ON ELECTRICAL MACHINES AND SYSTEMS》 *
吴奇珂等: "基于蒙特卡洛的电网节点电压暂降风险分析", 《电气应用》 *
胡文曦等: "电网结构对电压暂降传播的影响及其量化分析方法", 《电力自动化设备》 *

Also Published As

Publication number Publication date
CN114243711B (en) 2022-11-08

Similar Documents

Publication Publication Date Title
Schneider et al. Analytic considerations and design basis for the IEEE distribution test feeders
Balamurugan et al. Review of power flow studies on distribution network with distributed generation
Khalid et al. Existing developments in adaptive smart grid protection: A review
CN104281979B (en) Distribution transformer platform area low voltage failure type detection method and system
CN109687436B (en) Grid optimization algorithm considering limitation of short-circuit current
CN103208797B (en) Estimation method for new-energy-containing power distribution network state based on intelligent optimization technology
Qin et al. Impact of system inherent characteristics on initial-stage short-circuit current of MMC-based MTDC transmission systems
Seifi et al. Power flow study and comparison of FACTS: Series (SSSC), Shunt (STATCOM), and Shunt-Series (UPFC)
Salimon et al. Load flow analysis of nigerian radial distribution network using backward/forward sweep technique
Xie et al. Wide-area stability control for damping interarea oscillations of interconnected power systems
CN104156531A (en) Fault current limiter distribution point optimization and capacity selection method taking operation loss into consideration
CN108631278A (en) The Optimal Configuration Method of breaker and fault current limiter in a kind of looped network formula direct-current micro-grid
CN112966364B (en) Photovoltaic power station equivalent model modeling method and device for characteristic value calculation
CN111756075B (en) Method for designing and testing power distribution system examples containing distributed power supply
CN114243711B (en) Large-scale power grid voltage sag evaluation method based on change branch influence domain
Lu et al. An optimal reactive power compensation allocation method considering the economic value affected by voltage sag
Liwei et al. New techniques for enhancing accuracy of EMTP/TSP hybrid simulation algorithm
Jiehao et al. Dynamic VAR configuration of receiving-end power grid based on improved trajectory sensitivity index
Uwho et al. Implementing Artificial Neural Network Based DVR to Improve Power Quality of Rumuola-Rumuomoi 11kV Distribution Network
Li et al. A methodology for power quality evaluation in distribution network with distributed generation
Tian et al. Harmonic reduction via optimal power flow and the frequency coupling matrix
Lu et al. A unified power flow model for three-phase transformers in medium and low voltage distribution networks
Ma et al. Harmonie evaluation of grid with multiple harmonic sources based on DIgSILENT
Bracale et al. Comparison of Frequency Domain Modelling Techniques for Assessing the Harmonic Emissions of Low Voltage Photovoltaic Plants
CN114362181B (en) Uniform harmonic state estimation method suitable for alternating current-direct current hybrid power grid

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant