CN115411729B - Voltage stability judging method and device for power system - Google Patents
Voltage stability judging method and device for power system Download PDFInfo
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- CN115411729B CN115411729B CN202211213218.6A CN202211213218A CN115411729B CN 115411729 B CN115411729 B CN 115411729B CN 202211213218 A CN202211213218 A CN 202211213218A CN 115411729 B CN115411729 B CN 115411729B
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- 238000000034 method Methods 0.000 title claims abstract description 26
- 230000009191 jumping Effects 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 6
- 238000012850 discrimination method Methods 0.000 claims 1
- 241000334161 Cercis chinensis Species 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 244000144730 Amygdalus persica Species 0.000 description 3
- 235000006040 Prunus persica var persica Nutrition 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 239000010117 shenhua Substances 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000002459 sustained effect Effects 0.000 description 2
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 1
- 235000011613 Pinus brutia Nutrition 0.000 description 1
- 241000018646 Pinus brutia Species 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
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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
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0061—Details of emergency protective circuit arrangements concerning transmission of signals
-
- 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
- H02H7/28—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 for meshed systems
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- Locating Faults (AREA)
Abstract
The invention discloses a voltage stability judging method and device of a power system, wherein the method comprises the following steps: when detecting that a main protection refusing fault occurs to any voltage node, positioning the fault voltage node and selecting an initial low-voltage node from a plurality of voltage nodes; carrying out homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage nodes meeting the preset continuous low-voltage condition as target low-voltage nodes; traversing node topology by taking a fault voltage node as a starting point, and determining node distances between each target low-voltage node and the fault voltage node; and searching node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on the searching result, thereby accurately judging whether the voltage state of the power system is actually stable.
Description
Technical Field
The present invention relates to the field of voltage stability determining technologies, and in particular, to a method and an apparatus for determining voltage stability of an electric power system.
Background
In recent years, voltage stabilization problems in power systems are receiving increasing attention. In the receiving end area, the problem of transient voltage stability of the power system caused by insufficient local reactive power is particularly remarkable, and if the voltage stability of the receiving end area cannot be reliably evaluated and control measures can be timely taken, a large-range voltage breakdown and power failure accidents are likely to be caused.
In the existing power system, it is generally required to ensure that the voltage of each bus is stable after a fault occurs, specifically, the voltage stability is determined by a mode that the voltage level cannot be lower than a certain set value for a period of time, for example, a typical setting scheme sets the set value to 0.75p.u., and the time is set to 1s.
In the prior art, the main protection refusing action is also an important fault, and is different from common single-wire and double-wire tripping faults and the like in that all outgoing lines can jump after the faults, so that at least one bus (namely a main protection refusing action point) is required to be at least one voltage instability caused by becoming an isolated node after an accident. However, the judgment does not consider the factor that the node instability of the separated system does not affect the voltage stability after the fault, and can not accurately judge whether the power system is actually in a voltage stable state.
Disclosure of Invention
The invention provides a voltage stability judging method and device for an electric power system, which solve the technical problems that the voltage stability judgment of faults such as main protection refusal in the prior art does not consider the factor that the node instability of a separated system does not influence the voltage stability after the faults, and can not accurately judge whether the electric power system is actually in a voltage stable state.
The invention provides a voltage stability judging method of a power system, wherein the power system comprises a plurality of voltage nodes, and the voltage nodes form a node topology, and the method comprises the following steps:
when detecting that a main protection refusing fault occurs to any voltage node, positioning the fault voltage node and selecting an initial low voltage node from a plurality of voltage nodes;
carrying out homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage node meeting the preset continuous low-voltage condition as a target low-voltage node;
traversing the node topology by taking the fault voltage node as a starting point, and determining the node distance between each target low voltage node and the fault voltage node;
and searching the node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on a search result.
Optionally, when detecting that a main protection refusal fault occurs in any voltage node, the step of locating the fault voltage node and selecting an initial low voltage node from a plurality of voltage nodes includes:
when detecting that any voltage node has a main protection refusing fault, locating the voltage node with the main protection refusing fault as a fault voltage node;
and selecting a voltage node with the current voltage smaller than a preset voltage per unit value as an initial low voltage node.
Optionally, the initial low voltage node is provided with a node name; the step of merging the initial low voltage nodes in the same name and selecting the initial low voltage node meeting the preset continuous low voltage condition as the target low voltage node comprises the following steps:
carrying out homonymy combination on the initial low-voltage nodes according to the node names to obtain a plurality of intermediate low-voltage nodes;
and selecting an intermediate low-voltage node with the voltage level larger than a preset level threshold and the low-voltage duration larger than or equal to a preset time threshold as a target low-voltage node.
Optionally, the step of traversing the node topology with the fault voltage node as a starting point, determining a node distance between each of the target low voltage nodes and the fault voltage node includes:
traversing the node topology by taking the fault voltage node as a starting point, determining a target low voltage node adjacent to the starting point and marking a node distance as a preset node distance;
judging whether a target low-voltage node which does not mark the node distance exists or not;
if yes, taking the target low-voltage node marked with the node distance as a new starting point;
increasing the preset node distance according to a preset distance value;
and skipping to execute the steps of traversing the node topology, determining the target low-voltage nodes adjacent to the starting point and marking the node distance as the preset node distance until no target low-voltage nodes without marking the node distance exist.
Optionally, the step of searching the node topology by using the target low-voltage node to which the maximum node distance belongs and determining the voltage state of the power system based on the search result includes:
traversing the node topology, and judging whether a line connecting the voltage nodes exists in a target low-voltage node to which the maximum node distance belongs;
if the voltage state exists, judging that the voltage state of the power system at the current moment is a voltage instability state;
if not, judging whether the maximum node distance at the current moment is a preset distance threshold value;
if not, deleting all target low-voltage nodes corresponding to the maximum node distance, and jumping to execute the step of judging whether the node distance with the maximum current moment is a preset distance threshold value;
if yes, judging that the voltage state of the power system at the current moment is a voltage stable state.
The invention provides a voltage stability judging device of a power system, the power system comprises a plurality of voltage nodes, the voltage nodes form node topology, the device comprises:
the low-voltage node selection module is used for positioning a fault voltage node and selecting an initial low-voltage node from a plurality of voltage nodes when detecting that a main protection refusal operation fault occurs to any one of the voltage nodes;
the node merging and screening module is used for carrying out homonymous merging on the plurality of initial low-voltage nodes and selecting the initial low-voltage nodes meeting the preset continuous low-voltage condition as target low-voltage nodes;
the node distance determining module is used for traversing the node topology by taking the fault voltage node as a starting point and determining the node distance between each target low voltage node and the fault voltage node;
and the voltage state determining module is used for searching the node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on the searching result.
Optionally, the low voltage node selection module is specifically configured to:
when detecting that any voltage node has a main protection refusing fault, locating the voltage node with the main protection refusing fault as a fault voltage node;
and selecting a voltage node with the current voltage smaller than a preset voltage per unit value as an initial low voltage node.
Optionally, the initial low voltage node is provided with a node name; the node merging and screening module is specifically configured to:
carrying out homonymy combination on the initial low-voltage nodes according to the node names to obtain a plurality of intermediate low-voltage nodes;
and selecting an intermediate low-voltage node with the voltage level larger than a preset level threshold and the low-voltage duration larger than or equal to a preset time threshold as a target low-voltage node.
Optionally, the node distance determining module is specifically configured to:
traversing the node topology by taking the fault voltage node as a starting point, determining a target low voltage node adjacent to the starting point and marking a node distance as a preset node distance;
judging whether a target low-voltage node which does not mark the node distance exists or not;
if yes, taking the target low-voltage node marked with the node distance as a new starting point;
increasing the preset node distance according to a preset distance value;
and skipping to execute the steps of traversing the node topology, determining the target low-voltage nodes adjacent to the starting point and marking the node distance as the preset node distance until no target low-voltage nodes without marking the node distance exist.
Optionally, the voltage state determining module is specifically configured to:
traversing the node topology, and judging whether a line connecting the voltage nodes exists in a target low-voltage node to which the maximum node distance belongs;
if the voltage state exists, judging that the voltage state of the power system at the current moment is a voltage instability state;
if not, judging whether the maximum node distance at the current moment is a preset distance threshold value;
if not, deleting all target low-voltage nodes corresponding to the maximum node distance, and jumping to execute the step of judging whether the node distance with the maximum current moment is a preset distance threshold value;
if yes, judging that the voltage state of the power system at the current moment is a voltage stable state.
From the above technical scheme, the invention has the following advantages:
when detecting that a main protection refusing fault occurs to any voltage node, positioning the fault voltage node and selecting an initial low voltage node from a plurality of voltage nodes; carrying out homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage nodes meeting the preset continuous low-voltage condition as target low-voltage nodes; traversing node topology by taking a fault voltage node as a starting point, and determining node distances between each target low-voltage node and the fault voltage node; and searching node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on the searching result, thereby accurately judging whether the voltage state of the power system is actually stable.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a flowchart of a voltage stability determining method of an electric power system according to an embodiment of the present invention;
fig. 2 is a step flowchart of a voltage stability determining method of a power system according to a second embodiment of the present invention;
fig. 3 is a schematic node topology diagram of an electric power system according to an embodiment of the present invention;
fig. 4 is a schematic node topology diagram of an electric power system according to another embodiment of the present invention;
fig. 5 is a block diagram of a voltage stability determining device of a power system according to a third embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a voltage stability judging method and device for an electric power system, which are used for solving the technical problems that in the prior art, voltage instability judgment of faults such as main protection refusal is not carried out, the factor that node instability of a separated system does not influence voltage stability after the faults are not considered, and whether the electric power system is actually in a voltage stable state cannot be accurately judged.
In order to make the objects, features and advantages of the present invention more comprehensible, the technical solutions in the embodiments of the present invention are described in detail below with reference to the accompanying drawings, and it is apparent that the embodiments described below are only some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, fig. 1 is a flowchart illustrating a voltage stability determining method of an electric power system according to an embodiment of the invention.
The invention provides a voltage stability judging method of an electric power system, wherein the electric power system comprises a plurality of voltage nodes, the voltage nodes form node topology, and the method comprises the following steps:
step 101, when detecting that a main protection refusing fault occurs in any voltage node, positioning the fault voltage node and selecting an initial low voltage node from a plurality of voltage nodes;
the main protection refusing action fault refers to the fault type that faults can be cut off in the shortest time in the whole protection range of a protected element, other non-fault parts in the system are guaranteed to continue to operate, and after tripping or closing signals are sent out when tripping is needed for protection, the circuit breaker does not act.
In the embodiment of the application, when the voltage node in the power system is detected to have the main protection refusing fault, the voltage node with the main protection refusing fault is positioned to serve as a fault voltage node, and an initial low-voltage node lower than a threshold value is selected from a plurality of voltage nodes according to the voltage amplitude of each voltage node at the current moment.
Before the power system is detected, the simulation of all outgoing lines of the main protection rejection fault jump can be performed on a certain designated voltage node, and an initial low-voltage node is selected while the fault voltage node is determined.
102, carrying out homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage nodes meeting the preset continuous low-voltage condition as target low-voltage nodes;
and carrying out homonymy combination on the node topology of each initial low-voltage node according to the node name of each initial low-voltage node, and simultaneously selecting the initial low-voltage node meeting the continuous low-voltage condition to determine the initial low-voltage node as the target low-voltage node.
Wherein the sustained low voltage condition includes, but is not limited to, a limitation of voltage class and a limitation of sustained low voltage time.
Step 103, traversing node topology by taking a fault voltage node as a starting point, and determining node distances between each target low voltage node and the fault voltage node;
after determining the fault voltage node, traversing the node topology by taking the position of the fault voltage node in the node topology as a starting point, taking the position of the fault voltage node as 0, and determining the node distance between each target low voltage node and the fault voltage node according to the node topology.
And 104, searching node topology by adopting a target low-voltage node to which the maximum node distance belongs, and determining the voltage state of the power system based on the searching result.
After the distances of all the nodes are determined, searching for node topology from a target low-voltage node farthest from the fault voltage node, judging whether a line connected to other voltage nodes exists in the target low-voltage node to which the largest node distance belongs according to the node topology, if so, judging that the voltage state of the power system is unstable, if not, further judging whether the largest node distance is a preset distance threshold, and if so, judging that the power state of the power system is stable.
In the embodiment of the application, when detecting that a main protection refusal fault occurs in any voltage node, positioning the fault voltage node and selecting an initial low-voltage node from a plurality of voltage nodes; carrying out homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage nodes meeting the preset continuous low-voltage condition as target low-voltage nodes; traversing node topology by taking a fault voltage node as a starting point, and determining node distances between each target low-voltage node and the fault voltage node; and searching node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on the searching result, thereby accurately judging whether the voltage state of the power system is actually stable.
Referring to fig. 2, fig. 2 is a flowchart illustrating a voltage stability determining method of an electric power system according to a second embodiment of the present invention.
The invention provides a voltage stability judging method of an electric power system, wherein the electric power system comprises a plurality of voltage nodes, the voltage nodes form node topology, and the method comprises the following steps:
step 201, when detecting that a main protection refusal operation fault occurs in any voltage node, positioning the fault voltage node and selecting an initial low voltage node from a plurality of voltage nodes;
optionally, step 201 may comprise the sub-steps of:
when detecting that a main protection refusal fault occurs in any voltage node, locating the voltage node with the main protection refusal fault as a fault voltage node;
and selecting a voltage node with the current voltage smaller than a preset voltage per unit value as an initial low voltage node.
In the embodiment of the application, when detecting that a main protection refusing fault occurs in any voltage node, the voltage node with the main protection refusing fault is located to serve as a fault voltage node, and meanwhile, a voltage node with the current voltage smaller than a preset voltage threshold value, such as a voltage per unit value, is selected from all the voltage nodes to be determined as an initial low voltage node.
Wherein the voltage per unit value may be set to 0.75p.u.
Step 202, performing homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage nodes meeting a preset continuous low-voltage condition as target low-voltage nodes;
optionally, the initial low voltage node is provided with a node name, step 202 may comprise the sub-steps of:
carrying out homonymous combination on the initial low-voltage nodes according to the node names to obtain a plurality of intermediate low-voltage nodes;
and selecting an intermediate low-voltage node with the voltage level larger than a preset level threshold and the low-voltage duration larger than or equal to a preset time threshold as a target low-voltage node.
In this embodiment, node names are respectively set on each initial low-voltage node, the initial low-voltage nodes are combined in the same name according to each node name, the initial low-voltage nodes with the same node name are combined, meanwhile, the obtained plurality of intermediate low-voltage nodes are screened, and the intermediate low-voltage node with the voltage level greater than the preset level threshold and the low-voltage duration greater than or equal to the preset time threshold is selected as the target low-voltage node.
For example, table 1, which is formed by removing nodes on the order of 110kV and below (mainly focusing on nodes of 220kV and above), and removing some nodes with insufficient low voltage time (i.e., less than 1 s), may be as follows:
| numbering device | Node name | Low voltage threshold | Starting time (second) | Duration (seconds) |
| 292 | Gui Hechi K1525 | 0.750 | 0.200 | 1.400 |
| 293 | Gui Hechi K2525 | 0.750 | 0.200 | 1.400 |
| 614 | Gui Hechi 505225 | 0.750 | 0.210 | 1.390 |
| 615 | Gui Hechi D1525 | 0.750 | 0.300 | 0.810 |
| 2002 | Gui Qingyuan 1115 and 1115 | 0.750 | 0.380 | 0.780 |
| 616 | Gui Hechi D2525 | 0.750 | 0.300 | 0.750 |
| 2032 | Gui Duoji D1115 | 0.750 | 0.370 | 0.470 |
TABLE 1
From the table, after the initial low-voltage nodes are combined in the same name, the obtained intermediate low-voltage node is a cassia-river pool, the voltage levels of the celebration stations and the multi-Ji stations are low, the duration is insufficient, the obtained target low-voltage node is a cassia-river pool, the low-voltage threshold is 0.750, the duration is 1.400, and the starting time is 0.200.
Step 203, traversing the node topology by taking the fault voltage node as a starting point, and determining the node distance between each target low voltage node and the fault voltage node;
optionally, step 203 may comprise the sub-steps of:
traversing node topology by taking a fault voltage node as a starting point, determining a target low voltage node adjacent to the starting point and marking the node distance as a preset node distance;
judging whether a target low-voltage node with an unlabeled node distance exists or not;
if yes, taking the target low-voltage node with the marked node distance as a new starting point;
increasing a preset node distance according to a preset distance value;
and skipping to execute the steps of traversing the node topology, determining the target low-voltage nodes adjacent to the starting point and marking the node distances as preset node distances until no target low-voltage nodes with unmarked node distances exist.
In the embodiment of the application, the position of the fault voltage node in the node topology is used as a starting point, the node topology is traversed, the target low voltage node adjacent to the starting point is determined, the node distance of the target low voltage node is marked as the preset node distance, whether the target low voltage node with the unmarked node distance exists is further judged, if yes, the target low voltage node with the marked node distance is used as a new starting point, meanwhile, the preset node distance is increased to be used as a new preset node distance according to the preset distance value, the residual node topology is traversed again from the new starting point, the target low voltage node adjacent to the new starting point is determined, the new preset node distance is marked, and the preset node distance is marked until all the target low voltage nodes are marked.
Step 204, traversing the node topology, and judging whether a line for connecting the voltage nodes exists in the target low-voltage node to which the maximum node distance belongs;
step 205, if yes, determining that the voltage state of the power system at the current moment is a voltage instability state;
step 206, if not, judging whether the maximum node distance at the current moment is a preset distance threshold value;
step 207, if not, deleting all target low-voltage nodes corresponding to the maximum node distance, and jumping to execute the step of judging whether the maximum node distance at the current moment is a preset distance threshold value;
and step 208, if yes, determining that the voltage state of the power system at the current moment is a voltage stable state.
Referring to fig. 3, fig. 3 illustrates a node topology according to an embodiment of the present application.
In the embodiment of the application, when the voltage node of the peach loosening station has a main protection refusing fault, the initial low voltage node is selected and subjected to homonymous combination, the initial low voltage node with the voltage level larger than a preset level threshold and the low voltage duration larger than or equal to a preset time threshold is selected as a target low voltage node,as shown in table 2 below:
| numbering device | Node name | Low voltage threshold | Starting time (second) | Duration (seconds) |
| 8267 | Qiansong peach 51525. | 0.75 | 0.22 | 1.38 |
| 8374 | Qian flower wall D1115. | 0.75 | 0.26 | 1.34 |
| 8351 | Qian changxing D1115. | 0.75 | 0.28 | 1.24 |
| 8382 | Qian Xiushan D1115. | 0.75 | 0.3 | 1.19 |
TABLE 2
In this embodiment, after merging, removing the low voltage class node and removing the low voltage time insufficient node, the remaining nodes include: and calculating the node distance between each target low-voltage node and the pine peach station, determining that each node 1 has a flower wall and a flower mountain, and determining that each node 2 is a giant tree. Judging whether the giant timber station is also connected with other voltage nodes, and judging whether the giant timber station is not connected with other voltage nodes, deleting the giant timber node, judging a flower wall and a beautiful mountain, determining that the two points are not connected with the system, and judging that the voltage state of the power system at the current moment is a voltage stable state.
Referring to fig. 4, fig. 4 is a schematic node topology of an electric power system according to another embodiment of the invention.
In this embodiment, after the single-phase main protection of the Jiulong station refuses to operate, the low-voltage level nodes are combined and removed, and the low-voltage time insufficient nodes are removed, wherein the Jiulong and Jiulong 22 and Fu Cheng Hefu are different in 22 voltage levels, respectively 500kV and 220kV levels, and are connected through a transformer instead of a circuit, and the remaining nodes comprise: cuisine, jiulong, foodinto, zhu city (Shenhua), mound sea, cercis chinensis, pingyang, notching, field safety, sun Dong, and merging and drawing to calculate the corresponding node distances as shown in the following table 3:
| site(s) | Distance of |
| Jiulong (a kind of Jiulong) | 0 |
| Qin two | 1 |
| Good fortune coming | 1 |
| Punching mouth | 1 |
| Pearl city (Shenhua) | 2 |
| Combined type (i.e. combined pump type) | 2 |
| Fall-in-a-field device | 2 |
| Sun Dong | 2 |
| Pingyang | 2 |
| Cercis chinensis | 2 |
| Pier sea | 3 |
TABLE 3 Table 3
The pier sea node with the distance of 3 is only connected with Pingyang and Cercis chinensis, and is arranged in the row of the original low-voltage node, so that the pier sea node is deleted. In the layer with the distance of 2, the Zhu Cheng (Shenhua) is connected with the Meilin, the Cercis chinensis is connected with the Fengshan, and the flushing port is connected with Yan Ling, and the points are not in the range of the original low-voltage node, so that the electric power system is in a voltage instability state after the single-phase main protection of the Jiulong station is refused.
In the embodiment of the application, when detecting that a main protection refusing fault occurs in any voltage node, positioning the fault voltage node and selecting an initial low-voltage node from a plurality of voltage nodes; carrying out homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage nodes meeting the preset continuous low-voltage condition as target low-voltage nodes; traversing node topology by taking a fault voltage node as a starting point, and determining node distances between each target low-voltage node and the fault voltage node; and searching node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on the searching result, thereby accurately judging whether the voltage state of the power system is actually stable.
Referring to fig. 5, fig. 5 is a block diagram illustrating a voltage stability determining apparatus of a power system according to a third embodiment of the present invention.
The embodiment of the invention provides a voltage stability judging device of a power system, the power system comprises a plurality of voltage nodes, the voltage nodes form a node topology, and the device comprises:
the low-voltage node selection module 401 is configured to locate a faulty voltage node and select an initial low-voltage node from a plurality of voltage nodes when a main protection rejection fault is detected to occur at any voltage node;
the node merging and screening module 402 is configured to perform homonymous merging on a plurality of initial low-voltage nodes, and select an initial low-voltage node that meets a preset continuous low-voltage condition as a target low-voltage node;
a node distance determining module 403, configured to traverse the node topology with the fault voltage node as a starting point, and determine a node distance between each target low voltage node and the fault voltage node;
the voltage state determining module 404 is configured to search the node topology by using the target low-voltage node to which the maximum node distance belongs, and determine the voltage state of the power system based on the search result.
Optionally, the low voltage node selection module 401 is specifically configured to:
when detecting that a main protection refusal fault occurs in any voltage node, locating the voltage node with the main protection refusal fault as a fault voltage node;
and selecting a voltage node with the current voltage smaller than a preset voltage per unit value as an initial low voltage node.
Optionally, the initial low voltage node is provided with a node name; the node merging and screening module 402 is specifically configured to:
carrying out homonymous combination on the initial low-voltage nodes according to the node names to obtain a plurality of intermediate low-voltage nodes;
and selecting an intermediate low-voltage node with the voltage level larger than a preset level threshold and the low-voltage duration larger than or equal to a preset time threshold as a target low-voltage node.
Optionally, the node distance determining module 403 is specifically configured to:
traversing node topology by taking a fault voltage node as a starting point, determining a target low voltage node adjacent to the starting point and marking the node distance as a preset node distance;
judging whether a target low-voltage node with an unlabeled node distance exists or not;
if yes, taking the target low-voltage node with the marked node distance as a new starting point;
increasing a preset node distance according to a preset distance value;
and skipping to execute the steps of traversing the node topology, determining the target low-voltage nodes adjacent to the starting point and marking the node distances as preset node distances until no target low-voltage nodes with unmarked node distances exist.
Optionally, the voltage status determination module 404 is specifically configured to:
traversing node topology, and judging whether a line for connecting voltage nodes exists in a target low-voltage node to which the maximum node distance belongs;
if the voltage state exists, judging that the voltage state of the power system at the current moment is a voltage instability state;
if not, judging whether the maximum node distance at the current moment is a preset distance threshold value;
if not, deleting all target low-voltage nodes corresponding to the maximum node distance, and jumping to execute the step of judging whether the maximum node distance at the current moment is a preset distance threshold value;
if so, judging that the voltage state of the power system at the current moment is a voltage stable state.
It will be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process of the apparatus and modules described above may refer to the corresponding process in the foregoing method embodiment, which is not repeated herein.
In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A voltage stability discrimination method for an electrical power system, the electrical power system including a plurality of voltage nodes, the plurality of voltage nodes comprising a node topology, the method comprising:
when detecting that a main protection refusing fault occurs to any voltage node, positioning the fault voltage node and selecting an initial low voltage node from a plurality of voltage nodes;
carrying out homonymous combination on a plurality of initial low-voltage nodes, and selecting the initial low-voltage node meeting the preset continuous low-voltage condition as a target low-voltage node;
traversing the node topology by taking the fault voltage node as a starting point, and determining the node distance between each target low voltage node and the fault voltage node;
and searching the node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on a search result.
2. The method of claim 1, wherein the step of locating a failed voltage node and selecting an initial low voltage node from a plurality of voltage nodes when a main protection rejection failure is detected for any of the voltage nodes comprises:
when detecting that any voltage node has a main protection refusing fault, locating the voltage node with the main protection refusing fault as a fault voltage node;
and selecting a voltage node with the current voltage smaller than a preset voltage per unit value as an initial low voltage node.
3. The method of claim 1, wherein the initial low voltage node is provided with a node name; the step of merging the initial low voltage nodes in the same name and selecting the initial low voltage node meeting the preset continuous low voltage condition as the target low voltage node comprises the following steps:
carrying out homonymy combination on the initial low-voltage nodes according to the node names to obtain a plurality of intermediate low-voltage nodes;
and selecting an intermediate low-voltage node with the voltage level larger than a preset level threshold and the low-voltage duration larger than or equal to a preset time threshold as a target low-voltage node.
4. The method of claim 1, wherein the step of traversing the node topology starting from the failed voltage node, determining a node distance between each of the target low voltage nodes and the failed voltage node comprises:
traversing the node topology by taking the fault voltage node as a starting point, determining a target low voltage node adjacent to the starting point and marking a node distance as a preset node distance;
judging whether a target low-voltage node which does not mark the node distance exists or not;
if yes, taking the target low-voltage node marked with the node distance as a new starting point;
increasing the preset node distance according to a preset distance value;
and skipping to execute the steps of traversing the node topology, determining the target low-voltage nodes adjacent to the starting point and marking the node distance as the preset node distance until no target low-voltage nodes without marking the node distance exist.
5. The method of claim 1, wherein the step of searching the node topology using the target low voltage node to which the largest node distance belongs, and determining the voltage state in which the power system is based on the search result, comprises:
traversing the node topology, and judging whether a line connecting the voltage nodes exists in a target low-voltage node to which the maximum node distance belongs;
if the voltage state exists, judging that the voltage state of the power system at the current moment is a voltage instability state;
if not, judging whether the maximum node distance at the current moment is a preset distance threshold value;
if not, deleting all target low-voltage nodes corresponding to the maximum node distance, and jumping to execute the step of judging whether the node distance with the maximum current moment is a preset distance threshold value;
if yes, judging that the voltage state of the power system at the current moment is a voltage stable state.
6. A voltage stability discrimination apparatus for an electrical power system, the electrical power system including a plurality of voltage nodes, the plurality of voltage nodes comprising a node topology, the apparatus comprising:
the low-voltage node selection module is used for positioning a fault voltage node and selecting an initial low-voltage node from a plurality of voltage nodes when detecting that a main protection refusal operation fault occurs to any one of the voltage nodes;
the node merging and screening module is used for carrying out homonymous merging on the plurality of initial low-voltage nodes and selecting the initial low-voltage nodes meeting the preset continuous low-voltage condition as target low-voltage nodes;
the node distance determining module is used for traversing the node topology by taking the fault voltage node as a starting point and determining the node distance between each target low voltage node and the fault voltage node;
and the voltage state determining module is used for searching the node topology by adopting a target low-voltage node with the largest node distance, and determining the voltage state of the power system based on the searching result.
7. The apparatus of claim 6, wherein the low voltage node selection module is specifically configured to:
when detecting that any voltage node has a main protection refusing fault, locating the voltage node with the main protection refusing fault as a fault voltage node;
and selecting a voltage node with the current voltage smaller than a preset voltage per unit value as an initial low voltage node.
8. The apparatus of claim 6, wherein the initial low voltage node is provided with a node name; the node merging and screening module is specifically configured to:
carrying out homonymy combination on the initial low-voltage nodes according to the node names to obtain a plurality of intermediate low-voltage nodes;
and selecting an intermediate low-voltage node with the voltage level larger than a preset level threshold and the low-voltage duration larger than or equal to a preset time threshold as a target low-voltage node.
9. The apparatus of claim 6, wherein the node distance determination module is specifically configured to:
traversing the node topology by taking the fault voltage node as a starting point, determining a target low voltage node adjacent to the starting point and marking a node distance as a preset node distance;
judging whether a target low-voltage node which does not mark the node distance exists or not;
if yes, taking the target low-voltage node marked with the node distance as a new starting point;
increasing the preset node distance according to a preset distance value;
and skipping to execute the steps of traversing the node topology, determining the target low-voltage nodes adjacent to the starting point and marking the node distance as the preset node distance until no target low-voltage nodes without marking the node distance exist.
10. The apparatus of claim 6, wherein the voltage state determination module is specifically configured to:
traversing the node topology, and judging whether a line connecting the voltage nodes exists in a target low-voltage node to which the maximum node distance belongs;
if the voltage state exists, judging that the voltage state of the power system at the current moment is a voltage instability state;
if not, judging whether the maximum node distance at the current moment is a preset distance threshold value;
if not, deleting all target low-voltage nodes corresponding to the maximum node distance, and jumping to execute the step of judging whether the node distance with the maximum current moment is a preset distance threshold value;
if yes, judging that the voltage state of the power system at the current moment is a voltage stable state.
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