A method for ranking transient voltage stability support capabilities of generator sets based on grid structure

Abstract

The present invention discloses a method for ranking the transient voltage stability support capacity of a unit based on a grid structure, which belongs to the technical field of safe and stable control of electric power systems. The method comprises the following steps: obtaining the system's transient stability control fault and the load bus whose voltage recovers the slowest after the control fault occurs; calculating the transfer impedance of different generator sets to the fault occurrence point based on the system grid structure parameters before the fault, and calculating the electrical distance of different generator sets to the load bus whose voltage recovers the slowest based on the grid parameters of the system after the fault; obtaining the transient voltage stability support capacity index of the unit based on the two parameters of transfer impedance and electrical distance, and ranking the transient voltage stability support capacity of the unit. The present invention can achieve the ranking of the transient voltage stability support capacity of the unit without a large number of time domain simulation calculations, which is convenient for power grid operators to reasonably arrange the startup mode of the unit and ensure the safe operation of the power grid.

Description

Technical Field

[0001] The invention belongs to the technical field of power system safety and stability control, and in particular relates to a method for ranking transient voltage stability supporting capabilities of generator sets based on a grid structure. Background Art

[0002] The transient voltage stability problem is an important factor affecting the safety and stability level of the power grid and the power supply capacity. Maintaining a reasonable startup method is an important means to improve the transient voltage stability level of the power grid. Therefore, in order to improve the safety and stability level of the power grid, it is necessary to fully understand the transient voltage stability support capacity of each unit in the power grid, and select the appropriate unit to start up according to the transient voltage stability support capacity of the unit. However, the calculation of the transient voltage stability support capacity of the unit considering the grid structure requires a large amount of time-domain simulation calculation, which is time-consuming and costly. Summary of the invention

[0003] In order to solve the above technical problems existing in the transient voltage stability of the existing power grid, the present invention provides a method for ranking the transient voltage stability support capacity of the units based on the grid structure. The present invention is conducive to the grid dispatching staff to reasonably arrange the startup mode of the units to ensure the safe operation of the power grid.

[0004] The technical solution of the present invention to solve the above technical problem is: a method for ranking the transient voltage stability support capacity of a unit based on a grid structure, comprising the following steps:

[0005] Step 1: Obtain the bus node i where the temporary stability control fault of the power system occurs and the load bus node j that recovers the slowest when the temporary stability control fault occurs in the power system;

[0006] Step 2: Calculate the transfer impedance from group k to fault bus node i

[0007] Step 3: The electrical distance from computer group k to the load bus j where the voltage recovers the slowest when a temporary stability control fault occurs

[0008] Step 4: Transient voltage stability support capability index K of computer group k k , and according to the transient voltage stability support capability index K k Rank the units' transient voltage stability support capabilities.

[0009] The transfer impedance of computer group k to fault point i in step 2 It is based on the grid before the temporary stability control failure occurs. The calculation formula is as follows:

[0010]

[0011] in, is the voltage-boosting impedance of the kth power supply, Z ij (i, j = 1, 2, ..., n) are the elements of the node impedance matrix written with the high voltage side of the generator step-up transformer as the node column.

[0012] In step 3, the computer group k is the electrical distance of the load bus j with the slowest voltage recovery when the temporary stability control fault occurs. It is based on the grid after the temporary stability control failure occurs.

[0013] The transient voltage stability support capability index K of unit k in step 4 k The calculation formula is as follows:

[0014]

[0015] K of the unit k The larger the index value, the stronger the unit's ability to support the system's transient voltage stability.

[0016] Beneficial effects of the present invention: The present invention ranks the transient voltage stability supporting capabilities of the units based on grid data, without requiring a large amount of transient stability calculations, and can effectively reduce the computational workload of grid operation analysts, providing convenience for arranging grid operation modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0019] Principle of the present invention: The transient voltage stability support capability of the unit is mainly affected by the grid structure. The different positions of the unit in the power grid and the different changes in the grid after a fault occur will affect the unit's support capability for transient voltage.

[0020] like Figure 1 As shown, the present invention proposes a method for ranking the transient voltage stability supporting capacity of a unit based on a grid structure, comprising the following steps:

[0021] Step 1: First, obtain the bus node i where the temporary stability control fault of the system occurs and the load bus node j that recovers the slowest when the temporary stability control fault occurs in the system;

[0022] Step 2: Calculate the transfer impedance from group k to fault bus node i

[0023] Step 3: The electrical distance from computer group k to the load bus j where the voltage recovers the slowest when a temporary stability control fault occurs

[0024] Step 4: Transient voltage stability support capability index K of the computer group k , and according to the indicator K k Rank the units' transient voltage stability support capabilities.

[0025] In step 1 of the present invention, there are many methods for obtaining the bus node i where the temporary stability control fault of the system occurs and the load bus node j that recovers the slowest when the temporary stability control fault occurs in the system, and the present invention does not limit the specific implementation method. Generally, the bus node i where the temporary stability control fault of the system occurs and the load bus node j that recovers the slowest when the temporary stability control fault occurs in the system can be obtained by time domain simulation.

[0026] The transfer impedance of computer group k to fault point i in step 2 of the present invention is It is based on the grid before the temporary stability control failure occurs. The calculation formula is as follows:

[0027]

[0028] in, is the voltage-boosting impedance of the kth power supply, Z ij (i, j = 1, 2, ..., n) are the elements of the node impedance matrix written with the high voltage side of the generator step-up transformer as the node column.

[0029] The electrical distance from the computer group k in step 3 of the present invention to the load bus j whose voltage recovers the slowest when a temporary stability control fault occurs It is based on the grid after the temporary stability control failure occurs. There are many methods for calculating the electrical distance. The present invention does not limit the specific calculation method of the electrical distance. Generally, the electrical distance can be calculated by the Thevenin equivalent method.

[0030] The transient voltage stability support capability index K of unit k in step 4 of the present invention is k The calculation formula is as follows:

[0031]

[0032] When ranking the transient voltage stability support capabilities of the units, the K k The larger the index value, the stronger the unit's ability to support the system's transient voltage stability.

[0033] The transient voltage stability support capability index K of the grid parameter computer group is calculated based on the present invention. k, without the need for large-scale time-domain simulation analysis, the transient voltage stability support characteristics of the units can be sorted, reducing the workload of grid operators, providing guidance for grid operation mode arrangements, and ensuring safe and stable operation of the grid.

[0034] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A method for ranking transient voltage stability support capabilities of power generating units based on grid structure, characterized in that: The following steps are involved: Step 1: Obtain the bus node where the temporary stability control fault of the system occurs i The load bus node that recovers the slowest when a temporary stability restriction fault occurs in the system j ; Step 2: Computer Group k To the fault bus node i The transfer impedance ; The calculation formula is as follows: (1)； in, For the k The boost impedance of a power supply is changed. ( i ,j=1,2,……, n ) are the elements of the node impedance matrix written with the high voltage side of the generator step-up transformer as the node; Step 3: Computer Group k To the load bus whose voltage recovers the slowest when a temporary stability restriction fault occurs j Electrical distance ; Step 4: Computer Group k Transient voltage stability support capability index , and according to the indicators Rank the units' transient voltage stability support capabilities; Transient voltage stability support capability index The calculation formula is as follows: (2)。 2. The method according to claim 1, characterized in that In step 3, the computer group k To the load bus whose voltage recovers the slowest when a temporary stability restriction fault occurs j Electrical distance It is based on the grid after the temporary stability control failure occurs.

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