Generating electric substation load transfer control parameters

A method for generating electric substation load transfer control parameters includes adjusting elements in a fundamental scale matrix according to a condition change of a power grid, wherein the fundamental scale matrix is constructed based on the topology structure of the power grid, and the elements in the fundamental scale matrix represent switch information and risk values of paths between nodes of the power grid, wherein the switch information represents number of switching times required for connecting two nodes of the power grid; and performing operations on the adjusted fundamental scale matrix to generate switch information and risk values of paths for electric substation load transfer control, as electric substation load transfer control parameters.

FOREIGN PRIORITY

This application claims priority to Chinese Patent Application No. 201410034931.3, filed Jan. 24, 2014, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in its entirety are herein incorporated by reference.

BACKGROUND

The present invention relates generally to electric substation load transfer control, and more specifically, to a method for generating electric substation load transfer control parameters, a device for generating electric substation load transfer control parameters, and an electric substation load transfer control system.

Power supply reliability of electric power grids is one of the important aspects of daily life and normal business operation. However, there are a lot of outages that occur on a daily basis for main substations due to, for example, routine maintenance of the substations, accident examinations, repairs and so on. Outages may generally result in large-area blackouts or even large-area power cut accidents. Therefore, for the requirement of maintenance without blackout, it is required to switch the load of an outage electric substation to other substation. In this case, the load transfer strategy applied between electric substations will become critical. A substation load transfer strategy involves the determination of an optimal load transfer path, which means minimizing security risk (including transfer risk and operation risk). This requires meeting with a criterion of minimized load transfer risk.

In the prior art, transfer paths and their risks are analyzed manually. Manual analysis may be only performed for specific load or a transfer task for a specific electric substation. Once the transfer task is changed, it must be re-analyzed manually. Further, in the prior art, it is unable to process multiple load transfer tasks simultaneously. Also, in the design of load transfer control parameters, it is very difficult to take path risk (i.e., transfer risk) and switch risk (i.e., operation risk) into account at the same time. Further, for solutions in the prior art, power flow reverse examination is a very difficult task. Further, because power grids are generally on large scale and complicated, it is difficult to effectively provide parameters for transfer control unless the above factors are considered in an effective and comprehensive manner.

There is not a method provided in the prior art, which may effectively provide parameters for substation load transfer control.

SUMMARY

According to a first aspect of the present invention, there is provided a method for generating electric substation load transfer control parameters, comprising: adjusting elements in a fundamental scale matrix according to a condition change of a power grid, wherein the fundamental scale matrix is constructed based on the topology structure of the power grid, and the elements in the fundamental scale matrix represent switch information and risk values of paths between nodes of the power grid, wherein the switch information represents number of switching times required for connecting two nodes of the power grid; and performing operations on the adjusted fundamental scale matrix to generate switch information and risk values of paths for electric substation load transfer control, which are used as electric substation load transfer control parameters.

According to a second aspect of the present invention, there is provided a device for generating electric substation load transfer control parameters, comprising: an adjustment unit, configured to adjust elements in a fundamental scale matrix according to a condition change of a power grid, wherein the fundamental scale matrix is constructed based on the topology structure of the power grid, and the elements in the fundamental scale matrix represent switch information and risk values of paths between nodes of the power grid, wherein the switch information represents number of switching times required for connecting two nodes of the power grid; and an operation unit, configured to perform operations on the adjusted fundamental scale matrix to generate switch information and risk values of paths for electric substation load transfer control, which are used as electric substation load transfer control parameters.

According to a third aspect of the present invention, there is provided an electric substation load transfer control system, comprising the device for generating electric substation load transfer control parameters according to the present invention, and a transfer control device configured to control transfer operations in the power grid according to the switch information and risk values of paths generated by the device for generating electric substation load transfer control parameters.

Compared with the prior art, through generating electric substation load transfer control parameters based on a fundamental scale matrix, computational complexity may be reduced in the present invention. Further, because electric substation load transfer control parameters are provided by using a matrix, the present invention may provide more comprehensive information about various transfer schemes. Further, because the fundamental scale matrix comprises switch information and path risk values, switch risk and path risk may be taken into account at the same time during the process.

Other features and advantages of the present invention will become more apparent when reading the following detailed description of embodiments of the present invention with reference to drawings.

DETAILED DESCRIPTION

Referring now toFIG. 1, in which an exemplary computer system/server12which is applicable to implement the embodiments of the present invention is shown. Computer system/server12is only illustrative and is not intended to suggest any limitation as to the scope of use or functionality of embodiments of the invention described herein.

Below, embodiments and examples of this invention will be described with reference to drawings, in which repetitive portions may be omitted.

FIG. 2shows a flowchart of a method2000for generating electric substation load transfer control parameters according to an embodiment of this invention.

At step S2010, elements in a fundamental scale matrix are adjusted according to a condition change of a power grid. The fundamental scale matrix is constructed based on the topology structure of the power grid, and the elements in the fundamental scale matrix represent switch information and risk values of paths between nodes of the power grid. The switch information may represent, for example, number of switching times required for connecting two nodes of the power grid. The risk values may be, for example, empirical values. The risk values may be determined by experts based on their empirical knowledge. For example, at least one of the switch information and risk values of the elements may be adjusted according to a condition change of the power grid.

For example, the fundamental scale matrix may be stored in memory. A processor may be configured with instructions to read the fundamental scale matrix from the memory and to adjust corresponding elements in the fundamental scale matrix when the condition of the power grid changes. For example, if an outage occurs on a path of the power grid, a risk value of an element corresponding to the path in the fundamental scale matrix is modified to 0.

For example, the processor may be configured with instructions to store the adjusted fundamental scale matrix into the original memory or to store the adjusted fundamental scale matrix into a cache memory for processing.

At step S2020, operations are performed on the adjusted fundamental scale matrix to generate switch information and risk values of paths used for electric substation load transfer control, which are used as electric substation load transfer control parameters. The switch information and risk values of paths may be used as electric substation load transfer control parameters.

For example, the processor may be configured with instructions to read the adjusted fundamental scale matrix from the memory or cache memory and to then perform operations on the fundamental scale matrix.

The fundamental scale matrix may be defined by users as required. Expansion may be made to the fundamental scale matrix by users as needed. For example, the dimensions of the fundamental scale matrix may be simply adjusted by a user to reflect topology structures of different power grids.

Further, depending on different purposes of analysis, a user may select different operations, or a user may define operations by themselves.

In this invention, through maintaining a fundamental scale matrix to provide parameters for electric substation load transfer control, the complexity of data sources may be greatly reduced. Further, because switch information and risk values of paths are contained in the elements of the fundamental scale matrix, switch and risk factors may be considered at the same time in the operation. Further, because a user may self-define and/or expand the fundamental scale matrix, more flexibility may be provided for the user. Further, a matrix may also be resultant from the operation performed on the adjusted fundamental scale matrix. Switch information and risk values of various paths during the operation may be recorded in the resultant matrix at the same time, and thus this invention may provide more comprehensive information for transfer control.

Next, an example of an improvement made on the base of the embodiment of this invention will be described.

According to an example of this invention, the fundamental scale matrix may be re presented by {right arrow over (M)}=(si,jki,j)n×n, wherein n represents the number of nodes in a power grid, si,jrepresents switch information of a path from node i to node j in the power grid, and ki,jrepresents a risk value of a path from node i to node j. Those skilled in the art may conceive a variety of variants to the matrix {right arrow over (M)}, all of which fall within the scope of protection in this invention so long as these variants may be converted to a matrix {right arrow over (M)} and may be used to generate electric substation load transfer control parameters.

For example, in this example, the step of performing operations on the adjusted fundamental scale matrix may comprise: according to a specified order N, performing N−1 scale operations on the adjusted fundamental scale matrix {right arrow over (M)}, wherein the scale operation is as follows:

Θ is a specified meta operation. For example, depending on different purposes of analysis, the specified meta operation may be addition or multiplication. For example, when the determined risk values are failure probability values, the meta operation may be addition or multiplication, or when the determined risk values are conditional failure probability values depending on surrounding paths, the meta operation may be multiplication.

Performing operations on the fundamental scale matrix may further comprise: generating switch information and risk values of paths for electric substation load transfer control from the resultant matrix {right arrow over (MI)} obtained from the N−1 scale operations.

For example, the resultant matrix {right arrow over (MI)} itself may be used as parameters for electric substation load transfer control, to provide comprehensive information of various paths (for example, switch information and risk values of all paths). For example, switch information and risk values of paths may be searched in a target row or a target column of the resultant matrix {right arrow over (MI)}, as parameters for electric substation load transfer control. For example, paths with a minimum number of switching times may be searched at first, and then a path having a minimum risk value may be selected from the paths with the minimum number of switching times and is used as a transfer path.

In this example, the order N may represent the section number of a path from a node to another node, or (N−1) represents the number of intermediate nodes passed through from a node to another node. Thus, the largest range of N is from 1 to the section number of the longest path in the power grid. Users may specify order N as required. If a user wants to look up transfer states of direct paths, N may be set to 1. If a user wants to look up transfer states of paths passing through one intermediate node, N may be set to 2, and so on.

According to another example of this invention, the previous example may be partially improved. In this example, the fundamental scale matrix may further base on voltage levels of the power grid. In the fundamental scale matrix, sub-matrixes of various voltage levels are arranged in sequence on the main diagonal of the fundamental scale matrix according to their voltage levels.

In this example, before performing scale operations, the adjusted fundamental scale matrix is scanned to determine and mark elements causing reverse power flow paths. The scanned parts comprise various elements in sub-matrixes above sub-matrixes of various voltage levels in the adjusted fundamental scale matrix.

In this example, the scale operation may be redefined as follows:

In this example, elements marked as causing reverse power flow path are ignored in the scale operations.

In this example, through designing the structure of the fundamental scale matrix, this invention makes a reverse power flow examination easier. Further, elements causing reverse power flow are marked to enable the consideration of reverse power flow in the operations.

FIG. 3shows a block diagram of a device3000for generating electric substation load transfer control parameters according to an embodiment of this invention.

As shown inFIG. 3, the transfer control parameter generating device3000comprises an adjustment unit3010and an operation unit3020.

The adjustment unit3010is configured to adjust elements in a fundamental scale matrix according to a condition change of a power grid. The fundamental scale matrix is constructed based on the topology structure of the power grid, and the elements in the fundamental scale matrix represent switch information and risk values of paths between nodes of the power grid. The switch information represents number of switching times required for connecting two nodes of the power grid. The risk values may be, for example, empirical values. For example, the adjustment unit may be configured to adjust at least one of switch information and risk values for the elements according to a condition change of the power grid.

The operation unit3020is configured to perform operations on the adjusted fundamental scale matrix to generate switch information and risk values of paths for electric substation load transfer control, which are used as electric substation load transfer control parameters.

Those skilled in the art may understand that the adjustment unit3010and the operation unit3020may be implemented in various ways. For example, the adjustment unit3010and the operation unit3020may be realized by configuring a processor with instructions. For example, instructions may be stored in ROM. When a device is booted, instructions may be loaded into a programming device thereof from the ROM to realize the adjustment unit3010and the operation unit3020. For example, the adjustment unit3010and the operation unit3020may be firmware of a special device.

For example, the adjustment unit3010may read the fundamental scale matrix from memory and then adjust the fundamental scale matrix as described above. For example, the adjustment unit3010may directly send the adjusted fundamental scale matrix to the operation unit3020. Or the adjustment unit3010, for example, may store the adjusted fundamental scale matrix into memory and the operation unit3020may read the adjusted fundamental scale matrix from memory later.

In an example according to this invention, the fundamental scale matrix may be represented by {right arrow over (M)}=(si,jki,j)n×n, wherein n represents the number of nodes in a power grid, si,jrepresents switch information of a path from node i to node j in the power grid, and ki,jrepresents a risk value of a path from node i to node j. In this example, the operation unit3020may be configured to perform N−1 scale operations on the adjusted fundamental scale matrix {right arrow over (M)} according to the specified order N. The scale operation is as follows:

The condition represents a minimum value of {|ai1×b1r|, |ai2×b2r|, . . . , |ain×bnr|} under a minimum number of switching times.

Θ is a specified meta operation. For example, depending on different purposes of analysis, the specified meta operation may be addition or multiplication.

In this example, switch information and risk values of paths for electric substation load transfer control may be generated from the resultant matrix {right arrow over (MI)} obtained from the N−1 scale operations.

For example, switch information and risk values of paths in a target row or a target column of the resultant matrix {right arrow over (MI)} may be used as parameters for electric substation load transfer control.

For example, the largest range of N may be from 1 to the section number of the longest path in the power grid.

In an example according to this invention, the fundamental scale matrix may further be based on voltage levels of the power grid. In the fundamental scale matrix, sub-matrixes of various voltage levels are arranged in sequence on the main diagonal of the fundamental scale matrix according to their voltage levels.

In this example, the adjustment unit3010is further configured to scan various elements in sub-matrixes above sub-matrixes of various voltage levels in the adjusted fundamental scale matrix, so as to determine and mark elements that may cause reverse power flow paths.

In this example, the scale operation may be redefined as follows:

In this example, elements marked as causing reverse power flow paths are ignored in the scale operations.

FIG. 4shows a block diagram of an electric substation load transfer control system4000according to an embodiment of this invention. As shown inFIG. 4, the transfer control system4000may comprise a transfer control parameter generating device3000and a transfer control device4200according to this invention.

The transfer control parameter generating device3000generates switch information and risk values of paths for electric substation load transfer control.

For example, based on the switch information and risk values of paths for electric substation load transfer control, the transfer control device4200may be manually controlled to perform a transfer operation. For example, the transfer control parameter generating device3000may directly send switch information and risk values of paths for electric substation load transfer control to the transfer control device4200to automatically perform a transfer operation. For example, the transfer control device4200may select a path having the lowest risk value with a minimum number of switching times from the resultant matrix generated by the transfer control parameter generating device3000, as a transfer path for the transfer control operation.

FIG. 5shows an example according to this invention. A power grid shown inFIG. 5comprises three voltage levels: 220 KV, 110 KV and 35 KV, respectively. There are three 220 KV nodes A, B, C. There are three 110 KV nodes D, E, F. There is one 35 KV node G.FIG. 5shows paths between various nodes, as well as switch information and risk values of various paths.

A fundamental scale matrix on the right ofFIG. 5may be obtained from the power grid shown inFIG. 5. In this fundamental scale matrix, switch information is represented by “-”. One “-” represents one switch operation to be performed. In the fundamental scale matrix, the values represent risk values between two nodes.

The fundamental scale matrix shown inFIG. 5comprises three sub-matrixes: a 220 KV sub-matrix, a 110 KV sub-matrix and a 35 KV sub-matrix, respectively. These three sub-matrixes are arranged on the main diagonal of the fundamental scale matrix.

The fundamental scale matrix may be stored in memory. Those skilled in the art may understand that the matrix may be stored in many ways. For example, for a sparse matrix, instead of storing all elements in the matrix, it is only required to store some elements of the matrix. For example, various elements in the matrix may be sequentially stored in memory and may be accessed in a two dimensional manner when the matrix is to be read.

As shown inFIG. 6, an outage occurs on a path between node C and node D, and an outage occurs on a path between node F and node G.

Corresponding elements in the fundamental scale matrix may be adjusted by a processor configured with instructions or by a specific device. In the example shown inFIG. 6, risk value 0.8 from C to D is adjusted to 0 and risk value 0.9 from F to G is adjusted to 0.

With a processor configured with instructions or a specific device, a scale operation may be performed on the adjusted fundamental scale matrix {right arrow over (M)} according to Equation 1 or 3, to obtain a resultant matrix {right arrow over (M)}{right arrow over (M)}. The meta operation Θ in the scale computation is multiplication.

For example, element c6,7is taken as an example to explain the above operation, wherein c6,7=min(0.7×0.2, 0.5×0.6) under the condition min(-,- -), and thus c6,7=−0.14.

In the example shown inFIG. 6, for example, a user wants to look up a transfer path from the 220 KV level to the 35 KV level. As shown inFIG. 6, appropriate paths (and their parameters, including risk values and numbers of switching times, for example) are searched in rows A, B, C and column G (shown by blocks inFIG. 6) of the resultant matrix {right arrow over (M)}{right arrow over (M)}. It can be obtained through a search performed on matrix blocks of {right arrow over (M)} and {right arrow over (M)}{right arrow over (M)} that, for outages on the C→D section and the F→G section, all possible load transfer paths are as follows:

A->D->G, with risk value 0.16 and two switch actions (two “-”);

B->E->G, with risk value 0.42 and two switch actions (two “-”);

C->E->G, with risk value 0.18 and two switch actions (two “-”).

For example, switch information and risk values may be directly obtained from {right arrow over (M)}{right arrow over (M)}. For example, path information may be recorded during the operation, or a corresponding path may be determined according to switch information and risk values.

The user may select to transfer from A to G, or from B to G, or from C to G, as desired.

As shown inFIG. 7, an outage occurs on a path between mode F and node G.

Corresponding elements in the fundamental scale matrix may be adjusted by a processor configured with instructions or by a specific device. In the example shown inFIG. 7, risk value 0.9 from F to G is adjusted to 0.

By using a processor configured with instructions or a specific device, a reverse power flow examination may be performed on the adjusted fundamental scale matrix. For example, a reverse power flow examination may be performed on a sub-matrix above the 110 KV sub-matrix (corresponding to nodes D, E, F) and a sub-matrix above the 35 KV sub-matrix (corresponding to node G). It may be found after the examination that there is an element (A→D) causing reverse power flow in the sub-matrix above the 110 KV sub-matrix. This element is marked accordingly.

The adjusted and marked fundamental scale matrix is as follows:

Wherein, the symbol “&” represents that there is a risk of reverse power flow on the path.

By using a processor configured with instructions or a specific device, a scale computation may be performed on the adjusted fundamental scale matrix {right arrow over (M)} according to Equation 2 or 4, to obtain a resultant matrix {right arrow over (M)}{right arrow over (M)}. The meta operation Θ in the scale computation is multiplication.

For example, element c1,7may be taken as an example to explain the above computation, wherein c1,7=min(0.8×0.2) under the condition min(- -) and without elements marked as causing a reverse power flow path (element “−&0.8” indicates the presence of a reverse power flow path and is ignored), and thus c1,7=0.

In the example shown inFIG. 7, for example, a user wants to look up a transfer path from the 220 KV level to the 35 KV level. As shown inFIG. 7, appropriate paths (and their parameters, including risk values and numbers of switching times, for example) are searched in rows A, B, C and column G (shown by blocks inFIG. 7) of the resultant matrix {right arrow over (M)}{right arrow over (M)}. It can be obtained through a search performed on matrix blocks of {right arrow over (M)} and {right arrow over (M)}{right arrow over (M)} that, for the outage on the F→G section, all possible load transfer paths are as follows:

B->E->G, with risk value 0.42 and two switch actions (two “-”);

C->D->G, with risk value 0.16 and one switch actions (one “-”).

For example, switch information and risk values may be directly obtained from {right arrow over (M)}{right arrow over (M)}. For example, path information may be recorded during the computation, or a corresponding path may be determined according to switch information and risk values.

The user may select to transfer from B to G or from C to G as desired.