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CN115000942A - Short-circuit current calculation method, system, storage medium and calculation device - Google Patents

Short-circuit current calculation method, system, storage medium and calculation device Download PDF

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CN115000942A
CN115000942A CN202210629009.3A CN202210629009A CN115000942A CN 115000942 A CN115000942 A CN 115000942A CN 202210629009 A CN202210629009 A CN 202210629009A CN 115000942 A CN115000942 A CN 115000942A
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short
circuit
circuit current
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component
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周玲
杨长坤
续芷瑄
金超
王艺博
邓昊楠
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Hohai University HHU
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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
    • G—PHYSICS
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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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H02J2103/30—
    • 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
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract

本发明公开了一种短路电流计算方法、系统、存储介质及计算设备，本发明对配电网模型进行网格化划分，对网格化的配电网模型进行等值并简化，基于等值并简化后的配电网模型，实现短路电流计算，可适用于多能源接入配网。

Figure 202210629009

The invention discloses a short-circuit current calculation method, system, storage medium and calculation device. The invention divides the distribution network model into grids, and equivalences and simplifies the gridded distribution network model. And the simplified distribution network model realizes short-circuit current calculation, which can be applied to multi-energy access distribution network.

Figure 202210629009

Description

Short-circuit current calculation method, system, storage medium and calculation device
Technical Field
The invention relates to a short-circuit current calculation method, a short-circuit current calculation system, a storage medium and calculation equipment, and belongs to the field of distribution automation.
Background
With the continuous expansion of the scale of the power distribution network, the energy structure becomes more complex and diversified, and the accurate calculation of the short-circuit current becomes an important component of the distribution network and the protection calculation. At present, the traditional short-circuit current calculation mode of a single-power radial distribution network is a mode of taking manual calculation as a main mode and taking information calculation as an auxiliary mode, and a stage type current protection scheme is determined through short-circuit current calculation, so that the safe and reliable operation of a system is ensured. The traditional single-power radial network structure is only provided with a single power supply, and after the multi-energy access distribution network, because the switching of the distributed power supply is convenient, the output is indefinite, the bidirectional flow of the tide can be caused, the calculation of the short-circuit current is complex, and the traditional short-circuit current calculation mode is not suitable for a novel power system architecture.
Disclosure of Invention
The invention provides a short-circuit current calculation method, a short-circuit current calculation system, a storage medium and a calculation device, which solve the problems disclosed in the background art.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a short circuit current calculation method, comprising:
adopting a gridding technology to perform gridding division on the power distribution network model;
an extended ward equivalence method is adopted to conduct equivalence and simplification on the gridded power distribution network model;
and calculating the short-circuit current according to the equivalent and simplified distribution network model.
Adopting the meshing technology, carrying out meshing division on the power distribution network model, including:
and adopting a gridding technology to perform gridding division on the power distribution network model according to a three-level division principle of a power supply area, a power supply grid and a power supply unit.
In the extended ward equivalence method, the grid where the short circuit point is located is used as a research grid, and other grids irrelevant to the research grid are equivalent to branches between boundary nodes and power injection.
If the short circuit is a symmetrical short circuit, dividing a network where a short circuit fault node is located into a normal operation component network and a fault component network by adopting a superposition principle, and calculating the short circuit current;
and if the short circuit is an asymmetric short circuit, dividing the network where the short circuit fault node is located into a positive sequence network, a negative sequence network and a zero sequence network by adopting a symmetric component method, and calculating the short circuit current.
When the short circuit is symmetrical, the three-phase short circuit current calculation formula is as follows:
Figure BDA0003679075840000021
wherein, I ij Is the short-circuit current of the branch i-j,
Figure BDA0003679075840000022
is I ij Is/are as followsPhasor value，Z ij Is the impedance of branch i-j, Δ U i Is the short-circuit fault voltage component of node i,
Figure BDA0003679075840000023
is Delta U i Is/are as followsPhasor value，ΔU j Is the short-circuit fault voltage component of node j,
Figure BDA0003679075840000024
is Delta U j Is/are as followsPhasor value；
Figure BDA0003679075840000025
Figure BDA0003679075840000026
Wherein f is a short-circuit fault node, I f The current flowing out for the short-circuit fault node in the fault component network,
Figure BDA0003679075840000027
is I f Phasor value of (2), Z if Is the impedance of branch i-f, Z jf The impedances of branches j-f.
When the short circuit is asymmetric, the calculation formula of each sequence component of the short circuit current is as follows:
Figure BDA0003679075840000028
wherein, I ij1 Being the short circuit current positive sequence component of branch i-j,
Figure BDA0003679075840000031
is I ij1 Phasor value of (I) ij2 Being the negative sequence component of the short-circuit current of branch i-j,
Figure BDA0003679075840000032
is I ij2 Phasor value of (I) ij0 Is the short-circuit current zero-sequence component of branch i-j,
Figure BDA0003679075840000033
is I ij0 Phasor value of, Z ij1 Is the impedance positive sequence component, Z, of branch i-j ij2 Is the negative sequence component of the impedance of branch i-j, Z ij0 Impedance zero sequence rolling, U for branch i-j i1 Is the positive sequence component of the voltage at node i,
Figure BDA0003679075840000034
is U i1 Phasor value of U j1 Is the positive sequence component of the voltage at node j,
Figure BDA0003679075840000035
is U j1 Phasor value of (U) i2 Is the negative sequence component of the voltage at node i,
Figure BDA0003679075840000036
is U i2 Phasor value of U j2 Is the negative sequence component of the voltage at node j,
Figure BDA0003679075840000037
is U j2 Phasor value of (U) i0 Is the zero-sequence component of the voltage at node i,
Figure BDA0003679075840000038
is U i0 Phasor value of (U) j0 Is the zero-sequence component of the voltage at node j,
Figure BDA0003679075840000039
is U j0 The phasor value of (a).
The method is implemented by means of a digital twin system of a power distribution network.
A short circuit current calculation system comprising:
the division module is used for carrying out gridding division on the power distribution network model by adopting a gridding technology;
the equivalence simplifying module is used for equating and simplifying the gridded power distribution network model by adopting an extended ward equivalence method;
and the calculation module is used for calculating the short-circuit current according to the equivalent and simplified power distribution network model.
A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform a short circuit current calculation method.
A computing device comprising one or more processors, one or more memories, and one or more programs stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing a short circuit current calculation method.
The invention has the following beneficial effects: the method disclosed by the invention is used for gridding and dividing the power distribution network model, equating and simplifying the gridded power distribution network model, realizing short-circuit current calculation based on the equivalent and simplified power distribution network model, and being suitable for multi-energy access distribution networks.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a diagram of the power distribution network model after equivalence;
FIG. 3 is a simplified scheme;
FIG. 4(a) is a three-phase short-circuit network;
fig. 4(b) is a normal operation component network;
FIG. 4(c) is a fault component network;
FIG. 5(a) is a positive sequence network;
FIG. 5(b) is a negative sequence network;
fig. 5(c) is a zero sequence network.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
As shown in fig. 1, a short-circuit current calculation method includes the following steps:
step 1, adopting a gridding technology to perform gridding division on a power distribution network model;
step 2, equating and simplifying the gridded power distribution network model by adopting an extended ward equivalence method;
and 3, calculating the short-circuit current according to the equivalent and simplified power distribution network model.
The power distribution network model is divided in a gridding mode, the gridded power distribution network model is equivalent and simplified, short-circuit current calculation is achieved based on the equivalent and simplified power distribution network model, and the method is applicable to a multi-energy access power distribution network.
The method is implemented by means of a power distribution network digital twin platform, namely all steps of the method are carried out in the platform.
The digital twin platform of the power distribution network realizes the integrated modeling of a diagram, a model and a library on the basis of CIM, completes the primary modeling and the secondary modeling and maintenance of the system through the diagram, and completes the modeling and the library building of equipment by taking the drawing as a guide. The integrated graphical modeling tool of the digital twin platform graph model of the power distribution network supports the modeling of the distribution network, fully considers the characteristics of the distribution network and provides uniform graphical modeling support for various applications such as SCADA, PAS, DTS, DA, DPAS and the like.
When drawing a graph, the definition and the creation of the graphic elements of the interface are used for realizing the definition of the required equipment and the corresponding attributes in the power system. And automatically generating the electrical connection property between the devices according to the connection definition of the graphics between the graphics primitives, and realizing the correspondence between the devices and the secondary information according to the mapping of the quantity measurement between the devices. And according to the graph page, all the measurement quantities are classified, layered, uniformly managed and inquired. The method can support the detection of the connection rationality between the devices and the topology analysis of the network according to the graphic page.
The graphical configuration function provided by the graphical modeling tool of the digital twin platform of the power distribution network is more flexible, and comprises primitive definition, graph drawing, physical object and attribute definition thereof, measurement mapping, graph and resource management, object management, graph display and data refreshing, user operation, interface customization, alarm and animation support and the like. The engineering template of the graphic elements can be flexibly defined according to the requirements of users, including the basic definition of the graphic elements, the definition of electric power, the definition of drawing, the definition of connection attributes and the definition of state quantity display. The user can also define the connection relation, the connection effectiveness, the equipment naming rule and the like of the templates through the electric power primitive interface template, for example, through the interval template, the definition of the power distribution station template can provide great convenience for rapidly drawing a plant station wiring diagram, switching station, power distribution station wiring diagram and inputting related equipment parameters.
In the graphical modeling tool presentation page, a menu bar, a tool bar, a primitive window, a property page, a drawing area, and a drawing area are included. The platform is provided with basic primitives, electric primitives, control primitives and the like, and also provides commonly used vector primitives to support the self-definition of primitive attributes. The drawing canvas of the drawing area is displayed in a free scaling mode, a single drawing can be provided with a plurality of layers, a plurality of types and types of panels can be generated on a running state interface by combining scripts, and meanwhile, the canvas drawing area has multiple display modes.
And importing the power distribution network model to be calculated into a power distribution network digital twin platform, and carrying out gridding division. The grid is defined by dividing a certain power supply area into a plurality of grid-shaped small areas according to a certain principle, so that the management of the area is more fine. The grid planning of the power distribution network refers to dividing a certain power distribution area into a plurality of power distribution grids according to the corresponding power utilization property, and subdividing each power distribution grid into a plurality of power supply units which are not overlapped with each other according to different development land depths and land properties, so that one power supply grid is used as a minimum management unit to carry out target planning and scheme making on the power distribution network.
The gridding division can be performed by layering and grading division according to the three-level division principle of the power supply area, the power supply grid and the power supply unit.
The division of the power supply area is mainly determined according to the principles of reliability requirements, load density, administrative division, and the like, and the area may be specifically divided into six power supply areas such as a +, A, B, C, D, E and the like by referring to the importance level of the user, the developed level of economy, and the like, as shown in table 1.
TABLE 1 Power supply zone partitioning
Figure BDA0003679075840000061
The power supply grid is divided into power supply land areas formed by target net racks formed by standardized connecting wires such as a single-ring network, an N-supply one-standby network, a double-ring network and multi-section moderate connection; the standard wiring within the power grid is preferably planned as one set and should not exceed three sets.
The power supply grid is constructed according to the property of land, the progress of land block construction, the load and the power supply; on the premise of ensuring the moderate scale of a power grid, in a long term, 2-4 public transformer substations need to supply power to grids, and the grids with the voltage level of 10kV need to be kept independent; the areas where the power supply grids are located should belong to the same power supply area.
The power distribution network unit division is further refined and perfected by gridding planning, and a plurality of power supply units are definite to form a power supply unit divided by the gridding planning. The power supply unit utilizes obvious and clear geographic characteristics of rivers, main roads and the like in a grid, comprehensively considers the load characteristics and the area of the area, divides the area into a plurality of power supply units, and determines the main power supply line and the standby power supply line in each unit by considering the actual load condition. The power supply unit is located in the same place with approximately same development requirement, and the reliability and development degree of the power supply are consistent.
The gridding layout planning takes a definite target as a primary premise of planning, then determines a required planning range and content, then carries out analysis on the current situation of the power distribution network to be researched, provides some planning methods and evaluation standards, and carries out related planning work on the target power distribution network after the work is finished.
And after the gridding is finished, equating and simplifying the gridded power distribution network model by adopting an extended ward equivalence method.
The extended ward method combines the simplicity of the conventional ward equivalence method and the reactive incremental response of the decoupled ward equivalence method; in the process of deducing the equivalent network, common methods of a conventional ward method, a ward-PV equivalent method and a decoupling ward method are adopted, the PV nodes of an external network are not reserved as the conventional ward method, all parallel branches of an external system are ignored as the ward-PV method, and the decoupling ward method is expanded to carry out external equivalence so as to reflect reactive incremental support of the external system.
The specific steps for constructing the extended ward method are as follows:
set to find
Figure BDA0003679075840000081
The following were used:
Figure BDA0003679075840000082
wherein,
Figure BDA0003679075840000083
is a node admittance matrix [ G 'added after the boundary node equivalence' EQ ]The conductance part of the node admittance matrix [ B 'added after the elimination of the external node and the equivalence of the boundary nodes' EQ ]The susceptance portion of the node admittance matrix added after the elimination of the external node and the equivalence of the boundary node, [ 2 ]]This is represented in matrix form.
Voltage modulus U at boundary node B And phase angle theta B When the change occurs, the boundary is automatically givenInjected active and reactive variables on the nodes:
Figure BDA0003679075840000084
Figure BDA0003679075840000085
wherein, U B In order to be the boundary node voltage magnitude,
Figure BDA0003679075840000086
the injected active variation on the back boundary node is simplified for the conventional Ward method.
Similar to the decoupled Ward method, it can be proved
Figure BDA0003679075840000087
And the reactive response equation of a good boundary node is as follows:
Figure BDA0003679075840000088
wherein,
Figure BDA0003679075840000089
for decoupling the injected reactive variables on the back boundary nodes simplified by the Ward method, [ B EQ ]The nanoarray is a nanoarray which eliminates all PV nodes in rows and columns.
Similar to the ward decoupling method, the equivalent effect of the ward node injection method is similar to that of the ward-PV equivalent method, and the model after equivalence according to the method is shown in FIG. 2.
It can be seen that when a decoupling warp equivalence method and an extension warp equivalence method are adopted, in order to support necessary reactive power increment, each boundary node needs to be added with an imaginary PV-type bus, so that the number of nodes of the equivalent network is greatly increased. In order to omit these imaginary nodes and obtain the same reactive power increment, it can be represented by fig. 3, where the self susceptance of the node i in fig. 3 is:
Figure BDA0003679075840000091
wherein, B i ′ i ' is the self susceptance of node i, and l represents the nodes l, B i ′ j ' is the susceptance value of branch ij, B i ′ i ' self susceptance for node i, B i ″ F The susceptance values of the branches i-F.
Therefore, the extended Ward equivalence method is combined with the gridding technology, in the extended Ward equivalence method, a grid where a short-circuit point is located serves as a research grid, namely an internal system, other grids irrelevant to the research grid are equivalent to branches and power injection between boundary nodes, namely other irrelevant grids serve as external systems, and the external systems in calculation are replaced by simplified branches, so that the calculation scale can be greatly reduced, and the calculation time is greatly shortened.
On the basis of the equivalent and simplified power distribution network model, corresponding short-circuit current calculation can be carried out according to different short-circuit types.
In the short circuit types, a single-phase ground short circuit, a two-phase interphase short circuit and the like belong to asymmetric short circuits, and a three-phase short circuit belongs to symmetric short circuits.
If the short circuit is a symmetrical short circuit, namely a three-phase short circuit, the network where the short circuit fault node is located is divided into a normal operation component network and a fault component network by adopting a superposition principle, and short circuit current calculation is carried out.
FIG. 4(a) is a three-phase short-circuit equivalent network, in which G is a generator (subscripts 1-n represent n generator numbers), E 'is an equivalent potential of the generator (subscripts 1-n represent n generator numbers), and X' d The reactance of the generator (subscripts 1 to n represent n generator numbers), the load (subscripts 1 to n represent n load numbers), and the fault node f.
Fig. 4(a) is divided into a normal operation component network fig. 4(b) and a failure component network fig. 4(c) using the superposition principle. Fig. 4(b) can be solved by load flow calculation, and fig. 4(c) can be solved by short circuit current calculation.
In the actual engineering calculation, approximate calculation is adopted, the influence of load is not considered, the normal state is set to be no-load, the voltage of each point of the network is set to be 1, in the fault component network,
Figure BDA0003679075840000101
U f0 is the open circuit voltage of the short circuit point,
Figure BDA0003679075840000102
is U f|0| The phasor value of (a). Therefore, only the calculation for the faulty component network is needed.
The specific calculation process is as follows:
firstly, solving a linear equation set through a node admittance matrix:
Figure BDA0003679075840000103
wherein Y is ii Is the self-admittance of node i, whose value is the sum of the admittances of all branches connected to node i, Y ij Is the mutual admittance of the node i and the node j, and the value is the negative value of the branch admittance between the node i and the node j, U 1 ～U n The voltage values of the nodes 1-n.
And (3) solving the voltage value of each node:
Figure BDA0003679075840000104
wherein,
Figure BDA0003679075840000105
is the voltage magnitude of node f, Z ff Is the self-impedance of the node f, the value of which is the voltage value of the short-circuit point when the unit current injected into the system at the short-circuit point f and the current injected into other nodes is zero, Z fn The mutual impedance between the node f and the node n is the voltage value of the node i when unit current is injected into the network at the short-circuit point f and the current of other nodes is zero.
The short-circuit current of the short-circuit fault node is:
Figure BDA0003679075840000111
as can be seen from the figure, the short-circuit fault node in the fault component network injects a current of-I f The fault voltage component of each node can be found by the following formula:
Figure BDA0003679075840000112
the voltage value after each node is shorted is as follows:
Figure BDA0003679075840000113
Figure BDA0003679075840000114
Figure BDA0003679075840000115
the short-circuit current for branch i-j is then:
Figure BDA0003679075840000116
wherein, I ij Is the short-circuit current of the branch i-j,
Figure BDA0003679075840000117
is I ij Is/are as followsPhasor value，Z ij Is the impedance of branch i-j, Δ U i Is the short-circuit fault voltage component of node i,
Figure BDA0003679075840000118
is Delta U i Is/are as followsPhasor value，ΔU j Is the short-circuit fault voltage component of node j,
Figure BDA0003679075840000119
is Delta U j Is/are as followsPhasor value；
Figure BDA00036790758400001110
Figure BDA00036790758400001111
Wherein f is a short-circuit fault node, I f The current flowing out for the short-circuit fault node in the fault component network,
Figure BDA00036790758400001112
is I f Phasor value of, Z if Is the impedance of branch i-f, Z jf The impedance of branch j-f.
The impedance of the power system except the fault point is three-phase symmetrical, if the short circuit is an asymmetric short circuit, a symmetrical component method is adopted, and the network where the short circuit fault node is located can be divided into a positive sequence network diagram 5(a), a negative sequence network diagram 5(b) and a zero sequence network diagram 5(c) for short circuit current calculation.
According to the superposition theorem, the three-sequence voltage of the power distribution network can be as follows:
Figure BDA0003679075840000121
Figure BDA0003679075840000122
Figure BDA0003679075840000123
wherein, U f1 、U f2 、U f0 Positive sequence voltage values, negative sequence voltage values and zero sequence voltage values of fault points,
Figure BDA0003679075840000124
are respectively U f1 、U f2 、U f0 Phasor value of U f(0) Is the value of the open circuit voltage at the short circuit point,
Figure BDA0003679075840000125
is U f(0) Phasor value of, Δ U f1 、ΔU f2 、ΔU f0 The positive sequence, negative sequence and zero sequence voltage values of the fault components,
Figure BDA0003679075840000126
are respectively Delta U f1 、ΔU f2 、ΔU f0 The phasor value of (a).
In normal operation, the distribution network contains only positive-sequence components, so in negative-sequence and zero-sequence networks
Figure BDA0003679075840000127
The fault component expression of each node voltage is:
Figure BDA0003679075840000128
Figure BDA0003679075840000129
Figure BDA00036790758400001210
wherein,
Figure BDA00036790758400001211
a three-sequence current phasor value of a fault point;
Figure BDA00036790758400001212
is the combined impedance of the fault point.
Thus, it is possible to obtain:
Figure BDA00036790758400001213
Figure BDA00036790758400001214
Figure BDA00036790758400001215
the above equation has 3n equations, the unknown quantity includes n positive, negative and zero sequence voltages and three-sequence short circuit currents of short circuit points, and the unknown quantity has 3n more than the equation number.
Considering various short-circuit fault boundary conditions (taking two-phase grounding short circuit as an example), the three-sequence current components of the special phase at the fault point can be obtained as follows:
Figure BDA0003679075840000131
where z is the ground impedance.
The voltage formula of each sequence of the fault port is the same as the above formula
Figure BDA0003679075840000132
The phasor value of each sequence component of the voltage of any node m is
Figure BDA0003679075840000133
Wherein,
Figure BDA0003679075840000134
the phasor value of the node m voltage in normal operation is generally approximately 1; z mf0 ～Z mf2 Is three-sequence network impedanceA column of elements in the matrix associated with the failure point f.
After the node voltage in each sequence network is calculated, the sequence current of any branch can be calculated by the following formula:
Figure BDA0003679075840000135
wherein, I ij1 Being the short circuit current positive sequence component of branch i-j,
Figure BDA0003679075840000136
is I ij1 Phasor value of (I) ij2 Being the negative sequence component of the short-circuit current of branch i-j,
Figure BDA0003679075840000137
is I ij2 Phasor value of (I) ij0 Is the short-circuit current zero-sequence component of branch i-j,
Figure BDA0003679075840000141
is I ij0 Phasor value of, Z ij1 Is the impedance positive sequence component, Z, of branch i-j ij2 Is the negative sequence component of the impedance of branch i-j, Z ij0 Impedance zero sequence rolling, U for branch i-j i1 Is the positive sequence component of the voltage at node i,
Figure BDA0003679075840000142
is U i1 Phasor value of U j1 Is the positive sequence component of the voltage at node j,
Figure BDA0003679075840000143
is U j1 Phasor value of U i2 Is the negative sequence component of the voltage at node i,
Figure BDA0003679075840000144
is U i2 Phasor value of U j2 Is the negative sequence component of the voltage at node j,
Figure BDA0003679075840000145
is U j2 Phasor value of U i0 Is the zero-sequence component of the voltage at node i,
Figure BDA0003679075840000146
is U i0 Phasor value of U j0 Is the zero-sequence component of the voltage at node j,
Figure BDA0003679075840000147
is U j0 The phasor value of (a).
According to the sequence component current, the calculation formula of each phase current can be obtained as follows:
Figure BDA0003679075840000148
wherein,
Figure BDA0003679075840000149
the phasor value of the three-phase current of the branch i-j;
Figure BDA00036790758400001410
Figure BDA00036790758400001411
in order to verify the method, short circuit calculation is carried out on a 10kV power distribution network in Jiangsu, a regional distribution network model is well established by using a graphical modeling tool of a digital twin platform and is stored in each file in a grid mode.
And taking a typical power distribution network mechanism as an object, and respectively calculating current and voltage values of different node positions and three-phase grounding short-circuit faults and interphase short-circuit faults. And comparing the fault current with the real fault current, and analyzing and calculating errors. In addition, the calculation time length of calculating the short-circuit current by analyzing manual calculation, simplifying network calculation without simplifying network calculation and expanding ward algorithm simplification network is shown in the following tables 2-4.
TABLE 2 short-circuit current comparison table for different short-circuit fault types
Figure BDA00036790758400001412
Figure BDA0003679075840000151
TABLE 3 short-circuit current comparison table for different short-circuit fault types
Figure BDA0003679075840000152
Figure BDA0003679075840000161
Table 4 table comparison table of calculated duration under different calculation methods
Figure BDA0003679075840000162
Figure BDA0003679075840000171
Experiments prove that the calculation of the short-circuit current is very accurate, and the daily operation requirement of the power distribution network can be met. Considering the calculation time, compared with the traditional method for manually calculating the short-circuit current, the method can greatly improve the calculation speed of the short-circuit current. In addition, experiments prove that the calculation rate can be obviously improved by simplifying the network structure by using the extended ward method.
Based on the same technical scheme, the invention also discloses a corresponding short-circuit current calculation system, which comprises:
the division module is used for carrying out gridding division on the power distribution network model by adopting a gridding technology;
the equivalence simplifying module is used for equating and simplifying the gridded power distribution network model by adopting an extended ward equivalence method;
and the calculation module is used for calculating the short-circuit current according to the equivalent and simplified power distribution network model.
Based on the same technical solution, the present invention also discloses a computer-readable storage medium storing one or more programs, the one or more programs including instructions, which when executed by a computing device, cause the computing device to execute a short-circuit current calculation method.
A computing device comprising one or more processors, one or more memories, and one or more programs stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing a short circuit current calculation method.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.

Claims (10)

1.一种短路电流计算方法，其特征在于，包括：1. a short-circuit current calculation method, is characterized in that, comprises: 采用网格化技术，对配电网模型进行网格化划分；Using grid technology, the distribution network model is divided into grid; 采用扩展ward等值法，对网格化的配电网模型进行等值并简化；Using the extended ward equivalence method, the gridded distribution network model is equivalent and simplified; 根据等值并简化后的配电网模型，进行短路电流计算。According to the equivalent and simplified distribution network model, the short-circuit current calculation is carried out. 2.根据权利要求1所述的一种短路电流计算方法，其特征在于，采用网格化技术，对配电网模型进行网格化划分，包括：2. A kind of short-circuit current calculation method according to claim 1, is characterized in that, adopts grid technology, carries out grid division to distribution network model, comprises: 采用网格化技术，按照供电区域、供电网格、供电单元的三级划分原则，对配电网模型进行网格化划分。Using grid technology, according to the three-level division principle of power supply area, power supply grid, and power supply unit, the distribution network model is divided into grid. 3.根据权利要求1所述的一种短路电流计算方法，其特征在于，在扩展ward等值法中，将短路点所在的网格作为研究网格，将与研究网格不相关的其他网格等效为边界节点之间的支路和功率注入。3. a kind of short-circuit current calculation method according to claim 1 is characterized in that, in the extended ward equivalent method, the grid where the short-circuit point is located is used as a research grid, and other grids that are not relevant to the research grid are used. Lattice equivalents are branches and power injections between boundary nodes. 4.根据权利要求1所述的一种短路电流计算方法，其特征在于，若短路为对称短路，采用叠加原理，将短路故障节点所在网络分为成正常运行分量网络和故障分量网络，进行短路电流计算；4. a kind of short-circuit current calculation method according to claim 1, is characterized in that, if short-circuit is symmetrical short-circuit, adopt superposition principle, divide the network where short-circuit fault node is located into normal operation component network and fault component network, carry out short-circuit. current calculation; 若短路为不对称短路，采用对称分量法，将短路故障节点所在网络分为成正序网络、负序网络和零序网络，进行短路电流计算。If the short circuit is an asymmetric short circuit, the symmetrical component method is used to divide the network where the short-circuit fault node is located into a positive-sequence network, a negative-sequence network and a zero-sequence network to calculate the short-circuit current. 5.根据权利要求4所述的一种短路电流计算方法，其特征在于，对称短路时，三相短路电流计算公式为：5. A kind of short-circuit current calculation method according to claim 4, is characterized in that, during symmetrical short-circuit, the three-phase short-circuit current calculation formula is:
Figure FDA0003679075830000011
Figure FDA0003679075830000011
 其中，Iij为支路i-j的短路电流，
Figure FDA0003679075830000012
为Iij的相量值，Zij为支路i-j的阻抗，ΔUi为节点i的短路故障电压分量，
Figure FDA0003679075830000013
为ΔUi的相量值，ΔUj为节点j的短路故障电压分量，
Figure FDA0003679075830000021
为ΔUj的相量值；Among them, I ij is the short-circuit current of branch ij,
Figure FDA0003679075830000012
is the phasor value of I ij , Z ij is the impedance of branch ij, ΔU i is the short-circuit fault voltage component of node i,
Figure FDA0003679075830000013
is the phasor value of ΔU i , ΔU j is the short-circuit fault voltage component of node j,
Figure FDA0003679075830000021
is the phasor value of ΔU j ;
Figure FDA0003679075830000022
Figure FDA0003679075830000022
Figure FDA0003679075830000023
Figure FDA0003679075830000023
 其中，f为短路故障节点，If为故障分量网络中的短路故障节点流出的电流，
Figure FDA0003679075830000024
为If的相量值，Zif为支路i-f的阻抗，Zjf为支路j-f的阻抗。Among them, f is the short-circuit fault node, If is the current flowing out of the short-circuit fault node in the fault component network,
Figure FDA0003679075830000024
is the phasor value of I f , Z if is the impedance of the branch if, and Z jf is the impedance of the branch jf. 6.根据权利要求4所述的一种短路电流计算方法，其特征在于，不对称短路时，短路电流各序分量计算公式为：6. A kind of short-circuit current calculation method according to claim 4, is characterized in that, during asymmetric short-circuit, the short-circuit current each sequence component calculation formula is:
Figure FDA0003679075830000025
Figure FDA0003679075830000025
 其中，Iij1为支路i-j的短路电流正序分量，
Figure FDA0003679075830000026
为Iij1的相量值，Iij2为支路i-j的短路电流负序分量，
Figure FDA0003679075830000027
为Iij2的相量值，Iij0为支路i-j的短路电流零序分量，
Figure FDA0003679075830000028
为Iij0的相量值，Zij1为支路i-j的阻抗正序分量，Zij2为支路i-j的阻抗负序分量，Zij0为支路i-j的阻抗零序疯啦滚，Ui1为节点i的电压正序分量，
Figure FDA0003679075830000029
为Ui1的相量值，Uj1为节点j的电压正序分量，
Figure FDA00036790758300000210
为Uj1的相量值，Ui2为节点i的电压负序分量，
Figure FDA00036790758300000211
为Ui2的相量值，Uj2为节点j的电压负序分量，
Figure FDA00036790758300000212
为Uj2的相量值，Ui0为节点i的电压零序分量，
Figure FDA00036790758300000213
为Ui0的相量值，Uj0为节点j的电压零序分量，
Figure FDA00036790758300000214
为Uj0的相量值。Among them, I ij1 is the positive sequence component of the short-circuit current of the branch ij,
Figure FDA0003679075830000026
is the phasor value of I ij1, I ij2 is the negative sequence component of the short-circuit current of the branch ij,
Figure FDA0003679075830000027
is the phasor value of I ij2 , I ij0 is the zero-sequence component of the short-circuit current of the branch ij,
Figure FDA0003679075830000028
is the phasor value of I ij0 , Z ij1 is the positive-sequence impedance component of the branch ij, Z ij2 is the negative-sequence impedance component of the branch ij, Z ij0 is the zero-sequence impedance of the branch ij, and U i1 is the node The positive sequence component of the voltage of i,
Figure FDA0003679075830000029
is the phasor value of U i1 , U j1 is the voltage positive sequence component of node j,
Figure FDA00036790758300000210
is the phasor value of U j1 , U i2 is the voltage negative sequence component of node i,
Figure FDA00036790758300000211
is the phasor value of U i2 , U j2 is the voltage negative sequence component of node j,
Figure FDA00036790758300000212
is the phasor value of U j2 , U i0 is the voltage zero-sequence component of node i,
Figure FDA00036790758300000213
is the phasor value of U i0 , U j0 is the voltage zero-sequence component of node j,
Figure FDA00036790758300000214
is the phasor value of U j0 . 7.根据权利要求1～6任意一项所述的一种短路电流计算方法，其特征在于，所述方法依托配电网数字孪生系统实施。7 . The short-circuit current calculation method according to claim 1 , wherein the method is implemented by relying on a digital twin system of a distribution network. 8 . 8.一种短路电流计算系统，其特征在于，包括：8. A short-circuit current calculation system, characterized in that, comprising: 划分模块，采用网格化技术，对配电网模型进行网格化划分；The division module adopts grid technology to divide the distribution network model into grid; 等值简化模块，采用扩展ward等值法，对网格化的配电网模型进行等值并简化；Equivalent simplification module, using extended ward equivalence method to equivalence and simplify the gridded distribution network model; 计算模块，根据等值并简化后的配电网模型，进行短路电流计算。The calculation module performs short-circuit current calculation according to the equivalent and simplified distribution network model. 9.一种存储一个或多个程序的计算机可读存储介质，其特征在于，所述一个或多个程序包括指令，所述指令当由计算设备执行时，使得所述计算设备执行根据权利要求1至7所述的方法中的任一方法。9. A computer-readable storage medium storing one or more programs, characterized in that the one or more programs comprise instructions that, when executed by a computing device, cause the computing device to perform according to the claims Any of the methods described in 1 to 7. 10.一种计算设备，其特征在于，包括：10. A computing device, comprising: 一个或多个处理器、一个或多个存储器以及一个或多个程序，其中一个或多个程序存储在所述一个或多个存储器中并被配置为由所述一个或多个处理器执行，所述一个或多个程序包括用于执行根据权利要求1至7所述的方法中的任一方法的指令。one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and are configured to be executed by the one or more processors, The one or more programs comprise instructions for performing any of the methods of claims 1-7.
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CN106786536A (en) * 2016-12-29 2017-05-31 广东电网有限责任公司电力调度控制中心 Consider the method for estimating state of outer net extended Ward equivalent
CN109274127A (en) * 2018-11-27 2019-01-25 山西金鹤电力设计有限公司 Electrical simulation calculation method for distribution network with distributed power supply
CN110224385A (en) * 2019-06-21 2019-09-10 武汉大学 An optimal configuration method of superconducting fault current limiter in active distribution network

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103529275A (en) * 2013-10-25 2014-01-22 国家电网公司 Short-circuit current analysis method and device of regional power grid
CN106786536A (en) * 2016-12-29 2017-05-31 广东电网有限责任公司电力调度控制中心 Consider the method for estimating state of outer net extended Ward equivalent
CN109274127A (en) * 2018-11-27 2019-01-25 山西金鹤电力设计有限公司 Electrical simulation calculation method for distribution network with distributed power supply
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